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[libpcap] / pcap-rpcap.c

/*
 * Copyright (c) 2002 - 2005 NetGroup, Politecnico di Torino (Italy)
 * Copyright (c) 2005 - 2008 CACE Technologies, Davis (California)
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the Politecnico di Torino, CACE Technologies
 * nor the names of its contributors may be used to endorse or promote
 * products derived from this software without specific prior written
 * permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "ftmacros.h"

#include <string.h>             /* for strlen(), ... */
#include <stdlib.h>             /* for malloc(), free(), ... */
#include <stdarg.h>             /* for functions with variable number of arguments */
#include <errno.h>              /* for the errno variable */
#include "sockutils.h"
#include "pcap-int.h"
#include "rpcap-protocol.h"
#include "pcap-rpcap.h"

/*
 * This file contains the pcap module for capturing from a remote machine's
 * interfaces using the RPCAP protocol.
 *
 * WARNING: All the RPCAP functions that are allowed to return a buffer
 * containing the error description can return max PCAP_ERRBUF_SIZE characters.
 * However there is no guarantees that the string will be zero-terminated.
 * Best practice is to define the errbuf variable as a char of size
 * 'PCAP_ERRBUF_SIZE+1' and to insert manually a NULL character at the end
 * of the buffer. This will guarantee that no buffer overflows occur even
 * if we use the printf() to show the error on the screen.
 *
 * XXX - actually, null-terminating the error string is part of the
 * contract for the pcap API; if there's any place in the pcap code
 * that doesn't guarantee null-termination, even at the expense of
 * cutting the message short, that's a bug and needs to be fixed.
 */

#define PCAP_STATS_STANDARD     0       /* Used by pcap_stats_rpcap to see if we want standard or extended statistics */
#ifdef _WIN32
#define PCAP_STATS_EX           1       /* Used by pcap_stats_rpcap to see if we want standard or extended statistics */
#endif

/*
 * \brief Keeps a list of all the opened connections in the active mode.
 *
 * This structure defines a linked list of items that are needed to keep the info required to
 * manage the active mode.
 * In other words, when a new connection in active mode starts, this structure is updated so that
 * it reflects the list of active mode connections currently opened.
 * This structure is required by findalldevs() and open_remote() to see if they have to open a new
 * control connection toward the host, or they already have a control connection in place.
 */
struct activehosts
{
        struct sockaddr_storage host;
        SOCKET sockctrl;
        uint8 protocol_version;
        struct activehosts *next;
};

/* Keeps a list of all the opened connections in the active mode. */
static struct activehosts *activeHosts;

/*
 * Keeps the main socket identifier when we want to accept a new remote
 * connection (active mode only).
 * See the documentation of pcap_remoteact_accept() and
 * pcap_remoteact_cleanup() for more details.
 */
static SOCKET sockmain;

/*
 * Private data for capturing remotely using the rpcap protocol.
 */
struct pcap_rpcap {
        /*
         * This is '1' if we're the network client; it is needed by several
         * functions (such as pcap_setfilter()) to know whether they have
         * to use the socket or have to open the local adapter.
         */
        int rmt_clientside;

        SOCKET rmt_sockctrl;            /* socket ID of the socket used for the control connection */
        SOCKET rmt_sockdata;            /* socket ID of the socket used for the data connection */
        int rmt_flags;                  /* we have to save flags, since they are passed by the pcap_open_live(), but they are used by the pcap_startcapture() */
        int rmt_capstarted;             /* 'true' if the capture is already started (needed to knoe if we have to call the pcap_startcapture() */
        char *currentfilter;            /* Pointer to a buffer (allocated at run-time) that stores the current filter. Needed when flag PCAP_OPENFLAG_NOCAPTURE_RPCAP is turned on. */

        uint8 protocol_version;         /* negotiated protocol version */

        unsigned int TotNetDrops;       /* keeps the number of packets that have been dropped by the network */

        /*
         * This keeps the number of packets that have been received by the
         * application.
         *
         * Packets dropped by the kernel buffer are not counted in this
         * variable. It is always equal to (TotAccepted - TotDrops),
         * except for the case of remote capture, in which we have also
         * packets in flight, i.e. that have been transmitted by the remote
         * host, but that have not been received (yet) from the client.
         * In this case, (TotAccepted - TotDrops - TotNetDrops) gives a
         * wrong result, since this number does not corresponds always to
         * the number of packet received by the application. For this reason,
         * in the remote capture we need another variable that takes into
         * account of the number of packets actually received by the
         * application.
         */
        unsigned int TotCapt;

        struct pcap_stat stat;
        /* XXX */
        struct pcap *next;              /* list of open pcaps that need stuff cleared on close */
};

/****************************************************
 *                                                  *
 * Locally defined functions                        *
 *                                                  *
 ****************************************************/
static struct pcap_stat *rpcap_stats_rpcap(pcap_t *p, struct pcap_stat *ps, int mode);
static int pcap_pack_bpffilter(pcap_t *fp, char *sendbuf, int *sendbufidx, struct bpf_program *prog);
static int pcap_createfilter_norpcappkt(pcap_t *fp, struct bpf_program *prog);
static int pcap_updatefilter_remote(pcap_t *fp, struct bpf_program *prog);
static void pcap_save_current_filter_rpcap(pcap_t *fp, const char *filter);
static int pcap_setfilter_rpcap(pcap_t *fp, struct bpf_program *prog);
static int pcap_setsampling_remote(pcap_t *fp);
static int pcap_startcapture_remote(pcap_t *fp);
static int rpcap_sendauth(SOCKET sock, uint8 *ver, struct pcap_rmtauth *auth, char *errbuf);
static int rpcap_recv_msg_header(SOCKET sock, struct rpcap_header *header, char *errbuf);
static int rpcap_check_msg_ver(SOCKET sock, uint8 expected_ver, struct rpcap_header *header, char *errbuf);
static int rpcap_check_msg_type(SOCKET sock, uint8 request_type, struct rpcap_header *header, uint16 *errcode, char *errbuf);
static int rpcap_process_msg_header(SOCKET sock, uint8 ver, uint8 request_type, struct rpcap_header *header, char *errbuf);
static int rpcap_recv(SOCKET sock, void *buffer, size_t toread, uint32 *plen, char *errbuf);
static void rpcap_msg_err(SOCKET sockctrl, uint32 plen, char *remote_errbuf);
static int rpcap_discard(SOCKET sock, uint32 len, char *errbuf);
static int rpcap_read_packet_msg(SOCKET sock, pcap_t *p, size_t size);

/****************************************************
 *                                                  *
 * Function bodies                                  *
 *                                                  *
 ****************************************************/

/*
 * This function translates (i.e. de-serializes) a 'rpcap_sockaddr'
 * structure from the network byte order to a 'sockaddr_in" or
 * 'sockaddr_in6' structure in the host byte order.
 *
 * It accepts an 'rpcap_sockaddr' structure as it is received from the
 * network, and checks the address family field against various values
 * to see whether it looks like an IPv4 address, an IPv6 address, or
 * neither of those.  It checks for multiple values in order to try
 * to handle older rpcap daemons that sent the native OS's 'sockaddr_in'
 * or 'sockaddr_in6' structures over the wire with some members
 * byte-swapped, and to handle the fact that AF_INET6 has different
 * values on different OSes.
 *
 * For IPv4 addresses, it converts the address family to host byte
 * order from network byte order and puts it into the structure,
 * sets the length if a sockaddr structure has a length, converts the
 * port number to host byte order from network byte order and puts
 * it into the structure, copies over the IPv4 address, and zeroes
 * out the zero padding.
 *
 * For IPv6 addresses, it converts the address family to host byte
 * order from network byte order and puts it into the structure,
 * sets the length if a sockaddr structure has a length, converts the
 * port number and flow information to host byte order from network
 * byte order and puts them into the structure, copies over the IPv6
 * address, and converts the scope ID to host byte order from network
 * byte order and puts it into the structure.
 *
 * The function will allocate the 'sockaddrout' variable according to the
 * address family in use. In case the address does not belong to the
 * AF_INET nor AF_INET6 families, 'sockaddrout' is not allocated and a
 * NULL pointer is returned.  This usually happens because that address
 * does not exist on the other host, or is of an address family other
 * than AF_INET or AF_INET6, so the RPCAP daemon sent a 'sockaddr_storage'
 * structure containing all 'zero' values.
 *
 * Older RPCAPDs sent the addresses over the wire in the OS's native
 * structure format.  For most OSes, this looks like the over-the-wire
 * format, but might have a different value for AF_INET6 than the value
 * on the machine receiving the reply.  For OSes with the newer BSD-style
 * sockaddr structures, this has, instead of a 2-byte address family,
 * a 1-byte structure length followed by a 1-byte address family.  The
 * RPCAPD code would put the address family in network byte order before
 * sending it; that would set it to 0 on a little-endian machine, as
 * htons() of any value between 1 and 255 would result in a value > 255,
 * with its lower 8 bits zero, so putting that back into a 1-byte field
 * would set it to 0.
 *
 * Therefore, for older RPCAPDs running on an OS with newer BSD-style
 * sockaddr structures, the family field, if treated as a big-endian
 * (network byte order) 16-bit field, would be:
 *
 *      (length << 8) | family if sent by a big-endian machine
 *      (length << 8) if sent by a little-endian machine
 *
 * For current RPCAPDs, and for older RPCAPDs running on an OS with
 * older BSD-style sockaddr structures, the family field, if treated
 * as a big-endian 16-bit field, would just contain the family.
 *
 * \param sockaddrin: a 'rpcap_sockaddr' pointer to the variable that has
 * to be de-serialized.
 *
 * \param sockaddrout: a 'sockaddr_storage' pointer to the variable that will contain
 * the de-serialized data. The structure returned can be either a 'sockaddr_in' or 'sockaddr_in6'.
 * This variable will be allocated automatically inside this function.
 *
 * \param errbuf: a pointer to a user-allocated buffer (of size PCAP_ERRBUF_SIZE)
 * that will contain the error message (in case there is one).
 *
 * \return '0' if everything is fine, '-1' if some errors occurred. Basically, the error
 * can be only the fact that the malloc() failed to allocate memory.
 * The error message is returned in the 'errbuf' variable, while the deserialized address
 * is returned into the 'sockaddrout' variable.
 *
 * \warning This function supports only AF_INET and AF_INET6 address families.
 *
 * \warning The sockaddrout (if not NULL) must be deallocated by the user.
 */

/*
 * Possible IPv4 family values other than the designated over-the-wire value,
 * which is 2 (because everybody uses 2 for AF_INET4).
 */
#define SOCKADDR_IN_LEN         16      /* length of struct sockaddr_in */
#define SOCKADDR_IN6_LEN        28      /* length of struct sockaddr_in6 */
#define NEW_BSD_AF_INET_BE      ((SOCKADDR_IN_LEN << 8) | 2)
#define NEW_BSD_AF_INET_LE      (SOCKADDR_IN_LEN << 8)

/*
 * Possible IPv6 family values other than the designated over-the-wire value,
 * which is 23 (because that's what Windows uses, and most RPCAP servers
 * out there are probably running Windows, as WinPcap includes the server
 * but few if any UN*Xes build and ship it).
 *
 * The new BSD sockaddr structure format was in place before 4.4-Lite, so
 * all the free-software BSDs use it.
 */
#define NEW_BSD_AF_INET6_BSD_BE         ((SOCKADDR_IN6_LEN << 8) | 24)  /* NetBSD, OpenBSD, BSD/OS */
#define NEW_BSD_AF_INET6_FREEBSD_BE     ((SOCKADDR_IN6_LEN << 8) | 28)  /* FreeBSD, DragonFly BSD */
#define NEW_BSD_AF_INET6_DARWIN_BE      ((SOCKADDR_IN6_LEN << 8) | 30)  /* macOS, iOS, anything else Darwin-based */
#define NEW_BSD_AF_INET6_LE             (SOCKADDR_IN6_LEN << 8)
#define LINUX_AF_INET6                  10
#define HPUX_AF_INET6                   22
#define AIX_AF_INET6                    24
#define SOLARIS_AF_INET6                26

static int
rpcap_deseraddr(struct rpcap_sockaddr *sockaddrin, struct sockaddr_storage **sockaddrout, char *errbuf)
{
        /* Warning: we support only AF_INET and AF_INET6 */
        switch (ntohs(sockaddrin->family))
        {
        case RPCAP_AF_INET:
        case NEW_BSD_AF_INET_BE:
        case NEW_BSD_AF_INET_LE:
                {
                struct rpcap_sockaddr_in *sockaddrin_ipv4;
                struct sockaddr_in *sockaddrout_ipv4;

                (*sockaddrout) = (struct sockaddr_storage *) malloc(sizeof(struct sockaddr_in));
                if ((*sockaddrout) == NULL)
                {
                        pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
                            errno, "malloc() failed");
                        return -1;
                }
                sockaddrin_ipv4 = (struct rpcap_sockaddr_in *) sockaddrin;
                sockaddrout_ipv4 = (struct sockaddr_in *) (*sockaddrout);
                sockaddrout_ipv4->sin_family = AF_INET;
                sockaddrout_ipv4->sin_port = ntohs(sockaddrin_ipv4->port);
                memcpy(&sockaddrout_ipv4->sin_addr, &sockaddrin_ipv4->addr, sizeof(sockaddrout_ipv4->sin_addr));
                memset(sockaddrout_ipv4->sin_zero, 0, sizeof(sockaddrout_ipv4->sin_zero));
                break;
                }

#ifdef AF_INET6
        case RPCAP_AF_INET6:
        case NEW_BSD_AF_INET6_BSD_BE:
        case NEW_BSD_AF_INET6_FREEBSD_BE:
        case NEW_BSD_AF_INET6_DARWIN_BE:
        case NEW_BSD_AF_INET6_LE:
        case LINUX_AF_INET6:
        case HPUX_AF_INET6:
        case AIX_AF_INET6:
        case SOLARIS_AF_INET6:
                {
                struct rpcap_sockaddr_in6 *sockaddrin_ipv6;
                struct sockaddr_in6 *sockaddrout_ipv6;

                (*sockaddrout) = (struct sockaddr_storage *) malloc(sizeof(struct sockaddr_in6));
                if ((*sockaddrout) == NULL)
                {
                        pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
                            errno, "malloc() failed");
                        return -1;
                }
                sockaddrin_ipv6 = (struct rpcap_sockaddr_in6 *) sockaddrin;
                sockaddrout_ipv6 = (struct sockaddr_in6 *) (*sockaddrout);
                sockaddrout_ipv6->sin6_family = AF_INET6;
                sockaddrout_ipv6->sin6_port = ntohs(sockaddrin_ipv6->port);
                sockaddrout_ipv6->sin6_flowinfo = ntohl(sockaddrin_ipv6->flowinfo);
                memcpy(&sockaddrout_ipv6->sin6_addr, &sockaddrin_ipv6->addr, sizeof(sockaddrout_ipv6->sin6_addr));
                sockaddrout_ipv6->sin6_scope_id = ntohl(sockaddrin_ipv6->scope_id);
                break;
                }
#endif

        default:
                /*
                 * It is neither AF_INET nor AF_INET6 (or, if the OS doesn't
                 * support AF_INET6, it's not AF_INET).
                 */
                *sockaddrout = NULL;
                break;
        }
        return 0;
}

/*
 * This function reads a packet from the network socket.  It does not
 * deliver the packet to a pcap_dispatch()/pcap_loop() callback (hence
 * the "nocb" string into its name).
 *
 * This function is called by pcap_read_rpcap().
 *
 * WARNING: By choice, this function does not make use of semaphores. A smarter
 * implementation should put a semaphore into the data thread, and a signal will
 * be raised as soon as there is data into the socket buffer.
 * However this is complicated and it does not bring any advantages when reading
 * from the network, in which network delays can be much more important than
 * these optimizations. Therefore, we chose the following approach:
 * - the 'timeout' chosen by the user is split in two (half on the server side,
 * with the usual meaning, and half on the client side)
 * - this function checks for packets; if there are no packets, it waits for
 * timeout/2 and then it checks again. If packets are still missing, it returns,
 * otherwise it reads packets.
 */
static int pcap_read_nocb_remote(pcap_t *p, struct pcap_pkthdr *pkt_header, u_char **pkt_data)
{
        struct pcap_rpcap *pr = p->priv;        /* structure used when doing a remote live capture */
        struct rpcap_header *header;            /* general header according to the RPCAP format */
        struct rpcap_pkthdr *net_pkt_header;    /* header of the packet, from the message */
        u_char *net_pkt_data;                   /* packet data from the message */
        uint32 plen;
        int retval;                             /* generic return value */
        int msglen;

        /* Structures needed for the select() call */
        struct timeval tv;                      /* maximum time the select() can block waiting for data */
        fd_set rfds;                            /* set of socket descriptors we have to check */

        /*
         * Define the packet buffer timeout, to be used in the select()
         * 'timeout', in pcap_t, is in milliseconds; we have to convert it into sec and microsec
         */
        tv.tv_sec = p->opt.timeout / 1000;
        tv.tv_usec = (p->opt.timeout - tv.tv_sec * 1000) * 1000;

        /* Watch out sockdata to see if it has input */
        FD_ZERO(&rfds);

        /*
         * 'fp->rmt_sockdata' has always to be set before calling the select(),
         * since it is cleared by the select()
         */
        FD_SET(pr->rmt_sockdata, &rfds);

        retval = select((int) pr->rmt_sockdata + 1, &rfds, NULL, NULL, &tv);
        if (retval == -1)
        {
#ifndef _WIN32
                if (errno == EINTR)
                {
                        /* Interrupted. */
                        return 0;
                }
#endif
                sock_geterror("select(): ", p->errbuf, PCAP_ERRBUF_SIZE);
                return -1;
        }

        /* There is no data waiting, so return '0' */
        if (retval == 0)
                return 0;

        /*
         * We have to define 'header' as a pointer to a larger buffer,
         * because in case of UDP we have to read all the message within a single call
         */
        header = (struct rpcap_header *) p->buffer;
        net_pkt_header = (struct rpcap_pkthdr *) ((char *)p->buffer + sizeof(struct rpcap_header));
        net_pkt_data = (u_char *)p->buffer + sizeof(struct rpcap_header) + sizeof(struct rpcap_pkthdr);

        if (pr->rmt_flags & PCAP_OPENFLAG_DATATX_UDP)
        {
                /* Read the entire message from the network */
                msglen = sock_recv_dgram(pr->rmt_sockdata, p->buffer,
                    p->bufsize, p->errbuf, PCAP_ERRBUF_SIZE);
                if (msglen == -1)
                {
                        /* Network error. */
                        return -1;
                }
                if (msglen == -3)
                {
                        /* Interrupted receive. */
                        return 0;
                }
                if ((size_t)msglen < sizeof(struct rpcap_header))
                {
                        /*
                         * Message is shorter than an rpcap header.
                         */
                        pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                            "UDP packet message is shorter than an rpcap header");
                        return -1;
                }
                plen = ntohl(header->plen);
                if ((size_t)msglen < sizeof(struct rpcap_header) + plen)
                {
                        /*
                         * Message is shorter than the header claims it
                         * is.
                         */
                        pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                            "UDP packet message is shorter than its rpcap header claims");
                        return -1;
                }
        }
        else
        {
                int status;

                if ((size_t)p->cc < sizeof(struct rpcap_header))
                {
                        /*
                         * We haven't read any of the packet header yet.
                         * The size we should get is the size of the
                         * packet header.
                         */
                        status = rpcap_read_packet_msg(pr->rmt_sockdata, p,
                            sizeof(struct rpcap_header));
                        if (status == -1)
                        {
                                /* Network error. */
                                return -1;
                        }
                        if (status == -3)
                        {
                                /* Interrupted receive. */
                                return 0;
                        }
                }

                /*
                 * We have the header, so we know how long the
                 * message payload is.  The size we should get
                 * is the size of the packet header plus the
                 * size of the payload.
                 */
                plen = ntohl(header->plen);
                if (plen > p->bufsize - sizeof(struct rpcap_header))
                {
                        /*
                         * This is bigger than the largest
                         * record we'd expect.  (We do it by
                         * subtracting in order to avoid an
                         * overflow.)
                         */
                        pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                            "Server sent us a message larger than the largest expected packet message");
                        return -1;
                }
                status = rpcap_read_packet_msg(pr->rmt_sockdata, p,
                    sizeof(struct rpcap_header) + plen);
                if (status == -1)
                {
                        /* Network error. */
                        return -1;
                }
                if (status == -3)
                {
                        /* Interrupted receive. */
                        return 0;
                }

                /*
                 * We have the entire message; reset the buffer pointer
                 * and count, as the next read should start a new
                 * message.
                 */
                p->bp = p->buffer;
                p->cc = 0;
        }

        /*
         * We have the entire message.
         */
        header->plen = plen;

        /*
         * Did the server specify the version we negotiated?
         */
        if (rpcap_check_msg_ver(pr->rmt_sockdata, pr->protocol_version,
            header, p->errbuf) == -1)
        {
                return 0;       /* Return 'no packets received' */
        }

        /*
         * Is this a RPCAP_MSG_PACKET message?
         */
        if (header->type != RPCAP_MSG_PACKET)
        {
                return 0;       /* Return 'no packets received' */
        }

        if (ntohl(net_pkt_header->caplen) > plen)
        {
                pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                    "Packet's captured data goes past the end of the received packet message.");
                return -1;
        }

        /* Fill in packet header */
        pkt_header->caplen = ntohl(net_pkt_header->caplen);
        pkt_header->len = ntohl(net_pkt_header->len);
        pkt_header->ts.tv_sec = ntohl(net_pkt_header->timestamp_sec);
        pkt_header->ts.tv_usec = ntohl(net_pkt_header->timestamp_usec);

        /* Supply a pointer to the beginning of the packet data */
        *pkt_data = net_pkt_data;

        /*
         * I don't update the counter of the packets dropped by the network since we're using TCP,
         * therefore no packets are dropped. Just update the number of packets received correctly
         */
        pr->TotCapt++;

        if (pr->rmt_flags & PCAP_OPENFLAG_DATATX_UDP)
        {
                unsigned int npkt;

                /* We're using UDP, so we need to update the counter of the packets dropped by the network */
                npkt = ntohl(net_pkt_header->npkt);

                if (pr->TotCapt != npkt)
                {
                        pr->TotNetDrops += (npkt - pr->TotCapt);
                        pr->TotCapt = npkt;
                }
        }

        /* Packet read successfully */
        return 1;
}

/*
 * This function reads a packet from the network socket.
 *
 * This function relies on the pcap_read_nocb_remote to deliver packets. The
 * difference, here, is that as soon as a packet is read, it is delivered
 * to the application by means of a callback function.
 */
static int pcap_read_rpcap(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
{
        struct pcap_rpcap *pr = p->priv;        /* structure used when doing a remote live capture */
        struct pcap_pkthdr pkt_header;
        u_char *pkt_data;
        int n = 0;
        int ret;

        /*
         * If this is client-side, and we haven't already started
         * the capture, start it now.
         */
        if (pr->rmt_clientside)
        {
                /* We are on an remote capture */
                if (!pr->rmt_capstarted)
                {
                        /*
                         * The capture isn't started yet, so try to
                         * start it.
                         */
                        if (pcap_startcapture_remote(p))
                                return -1;
                }
        }

        while (n < cnt || PACKET_COUNT_IS_UNLIMITED(cnt))
        {
                /*
                 * Has "pcap_breakloop()" been called?
                 */
                if (p->break_loop) {
                        /*
                         * Yes - clear the flag that indicates that it
                         * has, and return PCAP_ERROR_BREAK to indicate
                         * that we were told to break out of the loop.
                         */
                        p->break_loop = 0;
                        return (PCAP_ERROR_BREAK);
                }

                /*
                 * Read some packets.
                 */
                ret = pcap_read_nocb_remote(p, &pkt_header, &pkt_data);
                if (ret == 1)
                {
                        /*
                         * We got a packet.  Hand it to the callback
                         * and count it so we can return the count.
                         */
                        (*callback)(user, &pkt_header, pkt_data);
                        n++;
                }
                else if (ret == -1)
                {
                        /* Error. */
                        return ret;
                }
                else
                {
                        /*
                         * No packet; this could mean that we timed
                         * out, or that we got interrupted, or that
                         * we got a bad packet.
                         *
                         * Were we told to break out of the loop?
                         */
                        if (p->break_loop) {
                                /*
                                 * Yes.
                                 */
                                p->break_loop = 0;
                                return (PCAP_ERROR_BREAK);
                        }
                        /* No - return the number of packets we've processed. */
                        return n;
                }
        }
        return n;
}

/*
 * This function sends a CLOSE command to the capture server.
 *
 * It is called when the user calls pcap_close().  It sends a command
 * to our peer that says 'ok, let's stop capturing'.
 *
 * WARNING: Since we're closing the connection, we do not check for errors.
 */
static void pcap_cleanup_rpcap(pcap_t *fp)
{
        struct pcap_rpcap *pr = fp->priv;       /* structure used when doing a remote live capture */
        struct rpcap_header header;             /* header of the RPCAP packet */
        struct activehosts *temp;               /* temp var needed to scan the host list chain, to detect if we're in active mode */
        int active = 0;                         /* active mode or not? */

        /* detect if we're in active mode */
        temp = activeHosts;
        while (temp)
        {
                if (temp->sockctrl == pr->rmt_sockctrl)
                {
                        active = 1;
                        break;
                }
                temp = temp->next;
        }

        if (!active)
        {
                rpcap_createhdr(&header, pr->protocol_version,
                    RPCAP_MSG_CLOSE, 0, 0);

                /*
                 * Send the close request; don't report any errors, as
                 * we're closing this pcap_t, and have no place to report
                 * the error.
                 */
                (void)sock_send(pr->rmt_sockctrl, (char *)&header,
                    sizeof(struct rpcap_header), NULL, 0);
        }
        else
        {
                rpcap_createhdr(&header, pr->protocol_version,
                    RPCAP_MSG_ENDCAP_REQ, 0, 0);

                /*
                 * Send the end capture request; don't report any errors,
                 * as we're closing this pcap_t, and have no place to
                 * report the error.
                 */
                if (sock_send(pr->rmt_sockctrl, (char *)&header,
                    sizeof(struct rpcap_header), NULL, 0) == 0)
                {
                        /*
                         * Wait for the answer; don't report any errors,
                         * as we're closing this pcap_t, and have no
                         * place to report the error.
                         */
                        if (rpcap_process_msg_header(pr->rmt_sockctrl,
                            pr->protocol_version, RPCAP_MSG_ENDCAP_REQ,
                            &header, NULL) == 0)
                        {
                                (void)rpcap_discard(pr->rmt_sockctrl,
                                    header.plen, NULL);
                        }
                }
        }

        if (pr->rmt_sockdata)
        {
                sock_close(pr->rmt_sockdata, NULL, 0);
                pr->rmt_sockdata = 0;
        }

        if ((!active) && (pr->rmt_sockctrl))
                sock_close(pr->rmt_sockctrl, NULL, 0);

        pr->rmt_sockctrl = 0;

        if (pr->currentfilter)
        {
                free(pr->currentfilter);
                pr->currentfilter = NULL;
        }

        /* To avoid inconsistencies in the number of sock_init() */
        sock_cleanup();
}

/*
 * This function retrieves network statistics from our peer;
 * it provides only the standard statistics.
 */
static int pcap_stats_rpcap(pcap_t *p, struct pcap_stat *ps)
{
        struct pcap_stat *retval;

        retval = rpcap_stats_rpcap(p, ps, PCAP_STATS_STANDARD);

        if (retval)
                return 0;
        else
                return -1;
}

#ifdef _WIN32
/*
 * This function retrieves network statistics from our peer;
 * it provides the additional statistics supported by pcap_stats_ex().
 */
static struct pcap_stat *pcap_stats_ex_rpcap(pcap_t *p, int *pcap_stat_size)
{
        *pcap_stat_size = sizeof (p->stat);

        /* PCAP_STATS_EX (third param) means 'extended pcap_stats()' */
        return (rpcap_stats_rpcap(p, &(p->stat), PCAP_STATS_EX));
}
#endif

/*
 * This function retrieves network statistics from our peer.  It
 * is used by the two previous functions.
 *
 * It can be called in two modes:
 * - PCAP_STATS_STANDARD: if we want just standard statistics (i.e.,
 *   for pcap_stats())
 * - PCAP_STATS_EX: if we want extended statistics (i.e., for
 *   pcap_stats_ex())
 *
 * This 'mode' parameter is needed because in pcap_stats() the variable that
 * keeps the statistics is allocated by the user. On Windows, this structure
 * has been extended in order to keep new stats. However, if the user has a
 * smaller structure and it passes it to pcap_stats(), this function will
 * try to fill in more data than the size of the structure, so that memory
 * after the structure will be overwritten.
 *
 * So, we need to know it we have to copy just the standard fields, or the
 * extended fields as well.
 *
 * In case we want to copy the extended fields as well, the problem of
 * memory overflow no longer exists because the structure that's filled
 * in is part of the pcap_t, so that it can be guaranteed to be large
 * enough for the additional statistics.
 *
 * \param p: the pcap_t structure related to the current instance.
 *
 * \param ps: a pointer to a 'pcap_stat' structure, needed for compatibility
 * with pcap_stat(), where the structure is allocated by the user. In case
 * of pcap_stats_ex(), this structure and the function return value point
 * to the same variable.
 *
 * \param mode: one of PCAP_STATS_STANDARD or PCAP_STATS_EX.
 *
 * \return The structure that keeps the statistics, or NULL in case of error.
 * The error string is placed in the pcap_t structure.
 */
static struct pcap_stat *rpcap_stats_rpcap(pcap_t *p, struct pcap_stat *ps, int mode)
{
        struct pcap_rpcap *pr = p->priv;        /* structure used when doing a remote live capture */
        struct rpcap_header header;             /* header of the RPCAP packet */
        struct rpcap_stats netstats;            /* statistics sent on the network */
        uint32 plen;                            /* data remaining in the message */

        /*
         * If the capture has not yet started, we cannot request statistics
         * for the capture from our peer, so we return 0 for all statistics,
         * as nothing's been seen yet.
         */
        if (!pr->rmt_capstarted)
        {
                ps->ps_drop = 0;
                ps->ps_ifdrop = 0;
                ps->ps_recv = 0;
#if defined(_WIN32) && defined(ENABLE_REMOTE)
                if (mode == PCAP_STATS_EX)
                {
                        ps->ps_capt = 0;
                        ps->ps_sent = 0;
                        ps->ps_netdrop = 0;
                }
#endif /* _WIN32 && ENABLE_REMOTE */

                return ps;
        }

        rpcap_createhdr(&header, pr->protocol_version,
            RPCAP_MSG_STATS_REQ, 0, 0);

        /* Send the PCAP_STATS command */
        if (sock_send(pr->rmt_sockctrl, (char *)&header,
            sizeof(struct rpcap_header), p->errbuf, PCAP_ERRBUF_SIZE) < 0)
                return NULL;            /* Unrecoverable network error */

        /* Receive and process the reply message header. */
        if (rpcap_process_msg_header(pr->rmt_sockctrl, pr->protocol_version,
            RPCAP_MSG_STATS_REQ, &header, p->errbuf) == -1)
                return NULL;            /* Error */

        plen = header.plen;

        /* Read the reply body */
        if (rpcap_recv(pr->rmt_sockctrl, (char *)&netstats,
            sizeof(struct rpcap_stats), &plen, p->errbuf) == -1)
                goto error;

        ps->ps_drop = ntohl(netstats.krnldrop);
        ps->ps_ifdrop = ntohl(netstats.ifdrop);
        ps->ps_recv = ntohl(netstats.ifrecv);
#if defined(_WIN32) && defined(ENABLE_REMOTE)
        if (mode == PCAP_STATS_EX)
        {
                ps->ps_capt = pr->TotCapt;
                ps->ps_netdrop = pr->TotNetDrops;
                ps->ps_sent = ntohl(netstats.svrcapt);
        }
#endif /* _WIN32 && ENABLE_REMOTE */

        /* Discard the rest of the message. */
        if (rpcap_discard(pr->rmt_sockctrl, plen, p->errbuf) == -1)
                goto error;

        return ps;

error:
        /*
         * Discard the rest of the message.
         * We already reported an error; if this gets an error, just
         * drive on.
         */
        (void)rpcap_discard(pr->rmt_sockctrl, plen, NULL);

        return NULL;
}

/*
 * This function returns the entry in the list of active hosts for this
 * active connection (active mode only), or NULL if there is no
 * active connection or an error occurred.  It is just for internal
 * use.
 *
 * \param host: a string that keeps the host name of the host for which we
 * want to get the socket ID for that active connection.
 *
 * \param error: a pointer to an int that is set to 1 if an error occurred
 * and 0 otherwise.
 *
 * \param errbuf: a pointer to a user-allocated buffer (of size
 * PCAP_ERRBUF_SIZE) that will contain the error message (in case
 * there is one).
 *
 * \return the entry for this host in the list of active connections
 * if found, NULL if it's not found or there's an error.
 */
static struct activehosts *
rpcap_remoteact_getsock(const char *host, int *error, char *errbuf)
{
        struct activehosts *temp;                       /* temp var needed to scan the host list chain */
        struct addrinfo hints, *addrinfo, *ai_next;     /* temp var needed to translate between hostname to its address */
        int retval;

        /* retrieve the network address corresponding to 'host' */
        addrinfo = NULL;
        memset(&hints, 0, sizeof(struct addrinfo));
        hints.ai_family = PF_UNSPEC;
        hints.ai_socktype = SOCK_STREAM;

        retval = getaddrinfo(host, "0", &hints, &addrinfo);
        if (retval != 0)
        {
                pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "getaddrinfo() %s",
                    gai_strerror(retval));
                *error = 1;
                return NULL;
        }

        temp = activeHosts;

        while (temp)
        {
                ai_next = addrinfo;
                while (ai_next)
                {
                        if (sock_cmpaddr(&temp->host, (struct sockaddr_storage *) ai_next->ai_addr) == 0)
                        {
                                *error = 0;
                                freeaddrinfo(addrinfo);
                                return temp;
                        }

                        ai_next = ai_next->ai_next;
                }
                temp = temp->next;
        }

        if (addrinfo)
                freeaddrinfo(addrinfo);

        /*
         * The host for which you want to get the socket ID does not have an
         * active connection.
         */
        *error = 0;
        return NULL;
}

/*
 * This function starts a remote capture.
 *
 * This function is required since the RPCAP protocol decouples the 'open'
 * from the 'start capture' functions.
 * This function takes all the parameters needed (which have been stored
 * into the pcap_t structure) and sends them to the server.
 *
 * \param fp: the pcap_t descriptor of the device currently open.
 *
 * \return '0' if everything is fine, '-1' otherwise. The error message
 * (if one) is returned into the 'errbuf' field of the pcap_t structure.
 */
static int pcap_startcapture_remote(pcap_t *fp)
{
        struct pcap_rpcap *pr = fp->priv;       /* structure used when doing a remote live capture */
        char sendbuf[RPCAP_NETBUF_SIZE];        /* temporary buffer in which data to be sent is buffered */
        int sendbufidx = 0;                     /* index which keeps the number of bytes currently buffered */
        char portdata[PCAP_BUF_SIZE];           /* temp variable needed to keep the network port for the data connection */
        uint32 plen;
        int active = 0;                         /* '1' if we're in active mode */
        struct activehosts *temp;               /* temp var needed to scan the host list chain, to detect if we're in active mode */
        char host[INET6_ADDRSTRLEN + 1];        /* numeric name of the other host */

        /* socket-related variables*/
        struct addrinfo hints;                  /* temp, needed to open a socket connection */
        struct addrinfo *addrinfo;              /* temp, needed to open a socket connection */
        SOCKET sockdata = 0;                    /* socket descriptor of the data connection */
        struct sockaddr_storage saddr;          /* temp, needed to retrieve the network data port chosen on the local machine */
        socklen_t saddrlen;                     /* temp, needed to retrieve the network data port chosen on the local machine */
        int ai_family;                          /* temp, keeps the address family used by the control connection */

        /* RPCAP-related variables*/
        struct rpcap_header header;                     /* header of the RPCAP packet */
        struct rpcap_startcapreq *startcapreq;          /* start capture request message */
        struct rpcap_startcapreply startcapreply;       /* start capture reply message */

        /* Variables related to the buffer setting */
        int res;
        socklen_t itemp;
        int sockbufsize = 0;
        uint32 server_sockbufsize;

        /*
         * Let's check if sampling has been required.
         * If so, let's set it first
         */
        if (pcap_setsampling_remote(fp) != 0)
                return -1;

        /* detect if we're in active mode */
        temp = activeHosts;
        while (temp)
        {
                if (temp->sockctrl == pr->rmt_sockctrl)
                {
                        active = 1;
                        break;
                }
                temp = temp->next;
        }

        addrinfo = NULL;

        /*
         * Gets the complete sockaddr structure used in the ctrl connection
         * This is needed to get the address family of the control socket
         * Tip: I cannot save the ai_family of the ctrl sock in the pcap_t struct,
         * since the ctrl socket can already be open in case of active mode;
         * so I would have to call getpeername() anyway
         */
        saddrlen = sizeof(struct sockaddr_storage);
        if (getpeername(pr->rmt_sockctrl, (struct sockaddr *) &saddr, &saddrlen) == -1)
        {
                sock_geterror("getsockname(): ", fp->errbuf, PCAP_ERRBUF_SIZE);
                goto error_nodiscard;
        }
        ai_family = ((struct sockaddr_storage *) &saddr)->ss_family;

        /* Get the numeric address of the remote host we are connected to */
        if (getnameinfo((struct sockaddr *) &saddr, saddrlen, host,
                sizeof(host), NULL, 0, NI_NUMERICHOST))
        {
                sock_geterror("getnameinfo(): ", fp->errbuf, PCAP_ERRBUF_SIZE);
                goto error_nodiscard;
        }

        /*
         * Data connection is opened by the server toward the client if:
         * - we're using TCP, and the user wants us to be in active mode
         * - we're using UDP
         */
        if ((active) || (pr->rmt_flags & PCAP_OPENFLAG_DATATX_UDP))
        {
                /*
                 * We have to create a new socket to receive packets
                 * We have to do that immediately, since we have to tell the other
                 * end which network port we picked up
                 */
                memset(&hints, 0, sizeof(struct addrinfo));
                /* TEMP addrinfo is NULL in case of active */
                hints.ai_family = ai_family;    /* Use the same address family of the control socket */
                hints.ai_socktype = (pr->rmt_flags & PCAP_OPENFLAG_DATATX_UDP) ? SOCK_DGRAM : SOCK_STREAM;
                hints.ai_flags = AI_PASSIVE;    /* Data connection is opened by the server toward the client */

                /* Let's the server pick up a free network port for us */
                if (sock_initaddress(NULL, "0", &hints, &addrinfo, fp->errbuf, PCAP_ERRBUF_SIZE) == -1)
                        goto error_nodiscard;

                if ((sockdata = sock_open(addrinfo, SOCKOPEN_SERVER,
                        1 /* max 1 connection in queue */, fp->errbuf, PCAP_ERRBUF_SIZE)) == INVALID_SOCKET)
                        goto error_nodiscard;

                /* addrinfo is no longer used */
                freeaddrinfo(addrinfo);
                addrinfo = NULL;

                /* get the complete sockaddr structure used in the data connection */
                saddrlen = sizeof(struct sockaddr_storage);
                if (getsockname(sockdata, (struct sockaddr *) &saddr, &saddrlen) == -1)
                {
                        sock_geterror("getsockname(): ", fp->errbuf, PCAP_ERRBUF_SIZE);
                        goto error_nodiscard;
                }

                /* Get the local port the system picked up */
                if (getnameinfo((struct sockaddr *) &saddr, saddrlen, NULL,
                        0, portdata, sizeof(portdata), NI_NUMERICSERV))
                {
                        sock_geterror("getnameinfo(): ", fp->errbuf, PCAP_ERRBUF_SIZE);
                        goto error_nodiscard;
                }
        }

        /*
         * Now it's time to start playing with the RPCAP protocol
         * RPCAP start capture command: create the request message
         */
        if (sock_bufferize(NULL, sizeof(struct rpcap_header), NULL,
                &sendbufidx, RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, fp->errbuf, PCAP_ERRBUF_SIZE))
                goto error_nodiscard;

        rpcap_createhdr((struct rpcap_header *) sendbuf,
            pr->protocol_version, RPCAP_MSG_STARTCAP_REQ, 0,
            sizeof(struct rpcap_startcapreq) + sizeof(struct rpcap_filter) + fp->fcode.bf_len * sizeof(struct rpcap_filterbpf_insn));

        /* Fill the structure needed to open an adapter remotely */
        startcapreq = (struct rpcap_startcapreq *) &sendbuf[sendbufidx];

        if (sock_bufferize(NULL, sizeof(struct rpcap_startcapreq), NULL,
                &sendbufidx, RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, fp->errbuf, PCAP_ERRBUF_SIZE))
                goto error_nodiscard;

        memset(startcapreq, 0, sizeof(struct rpcap_startcapreq));

        /* By default, apply half the timeout on one side, half of the other */
        fp->opt.timeout = fp->opt.timeout / 2;
        startcapreq->read_timeout = htonl(fp->opt.timeout);

        /* portdata on the openreq is meaningful only if we're in active mode */
        if ((active) || (pr->rmt_flags & PCAP_OPENFLAG_DATATX_UDP))
        {
                sscanf(portdata, "%d", (int *)&(startcapreq->portdata));        /* cast to avoid a compiler warning */
                startcapreq->portdata = htons(startcapreq->portdata);
        }

        startcapreq->snaplen = htonl(fp->snapshot);
        startcapreq->flags = 0;

        if (pr->rmt_flags & PCAP_OPENFLAG_PROMISCUOUS)
                startcapreq->flags |= RPCAP_STARTCAPREQ_FLAG_PROMISC;
        if (pr->rmt_flags & PCAP_OPENFLAG_DATATX_UDP)
                startcapreq->flags |= RPCAP_STARTCAPREQ_FLAG_DGRAM;
        if (active)
                startcapreq->flags |= RPCAP_STARTCAPREQ_FLAG_SERVEROPEN;

        startcapreq->flags = htons(startcapreq->flags);

        /* Pack the capture filter */
        if (pcap_pack_bpffilter(fp, &sendbuf[sendbufidx], &sendbufidx, &fp->fcode))
                goto error_nodiscard;

        if (sock_send(pr->rmt_sockctrl, sendbuf, sendbufidx, fp->errbuf,
            PCAP_ERRBUF_SIZE) < 0)
                goto error_nodiscard;

        /* Receive and process the reply message header. */
        if (rpcap_process_msg_header(pr->rmt_sockctrl, pr->protocol_version,
            RPCAP_MSG_STARTCAP_REQ, &header, fp->errbuf) == -1)
                goto error_nodiscard;

        plen = header.plen;

        if (rpcap_recv(pr->rmt_sockctrl, (char *)&startcapreply,
            sizeof(struct rpcap_startcapreply), &plen, fp->errbuf) == -1)
                goto error;

        /*
         * In case of UDP data stream, the connection is always opened by the daemon
         * So, this case is already covered by the code above.
         * Now, we have still to handle TCP connections, because:
         * - if we're in active mode, we have to wait for a remote connection
         * - if we're in passive more, we have to start a connection
         *
         * We have to do he job in two steps because in case we're opening a TCP connection, we have
         * to tell the port we're using to the remote side; in case we're accepting a TCP
         * connection, we have to wait this info from the remote side.
         */
        if (!(pr->rmt_flags & PCAP_OPENFLAG_DATATX_UDP))
        {
                if (!active)
                {
                        memset(&hints, 0, sizeof(struct addrinfo));
                        hints.ai_family = ai_family;            /* Use the same address family of the control socket */
                        hints.ai_socktype = (pr->rmt_flags & PCAP_OPENFLAG_DATATX_UDP) ? SOCK_DGRAM : SOCK_STREAM;
                        pcap_snprintf(portdata, PCAP_BUF_SIZE, "%d", ntohs(startcapreply.portdata));

                        /* Let's the server pick up a free network port for us */
                        if (sock_initaddress(host, portdata, &hints, &addrinfo, fp->errbuf, PCAP_ERRBUF_SIZE) == -1)
                                goto error;

                        if ((sockdata = sock_open(addrinfo, SOCKOPEN_CLIENT, 0, fp->errbuf, PCAP_ERRBUF_SIZE)) == INVALID_SOCKET)
                                goto error;

                        /* addrinfo is no longer used */
                        freeaddrinfo(addrinfo);
                        addrinfo = NULL;
                }
                else
                {
                        SOCKET socktemp;        /* We need another socket, since we're going to accept() a connection */

                        /* Connection creation */
                        saddrlen = sizeof(struct sockaddr_storage);

                        socktemp = accept(sockdata, (struct sockaddr *) &saddr, &saddrlen);

                        if (socktemp == INVALID_SOCKET)
                        {
                                sock_geterror("accept(): ", fp->errbuf, PCAP_ERRBUF_SIZE);
                                goto error;
                        }

                        /* Now that I accepted the connection, the server socket is no longer needed */
                        sock_close(sockdata, fp->errbuf, PCAP_ERRBUF_SIZE);
                        sockdata = socktemp;
                }
        }

        /* Let's save the socket of the data connection */
        pr->rmt_sockdata = sockdata;

        /*
         * Set the size of the socket buffer for the data socket.
         * It has the same size as the local capture buffer used
         * on the other side of the connection.
         */
        server_sockbufsize = ntohl(startcapreply.bufsize);

        /* Let's get the actual size of the socket buffer */
        itemp = sizeof(sockbufsize);

        res = getsockopt(sockdata, SOL_SOCKET, SO_RCVBUF, (char *)&sockbufsize, &itemp);
        if (res == -1)
        {
                sock_geterror("pcap_startcapture_remote()", fp->errbuf, PCAP_ERRBUF_SIZE);
                SOCK_ASSERT(fp->errbuf, 1);
        }

        /*
         * Warning: on some kernels (e.g. Linux), the size of the user
         * buffer does not take into account the pcap_header and such,
         * and it is set equal to the snaplen.
         *
         * In my view, this is wrong (the meaning of the bufsize became
         * a bit strange).  So, here bufsize is the whole size of the
         * user buffer.  In case the bufsize returned is too small,
         * let's adjust it accordingly.
         */
        if (server_sockbufsize <= (u_int) fp->snapshot)
                server_sockbufsize += sizeof(struct pcap_pkthdr);

        /* if the current socket buffer is smaller than the desired one */
        if ((u_int) sockbufsize < server_sockbufsize)
        {
                /*
                 * Loop until the buffer size is OK or the original
                 * socket buffer size is larger than this one.
                 */
                while (1)
                {
                        res = setsockopt(sockdata, SOL_SOCKET, SO_RCVBUF,
                            (char *)&(server_sockbufsize),
                            sizeof(server_sockbufsize));

                        if (res == 0)
                                break;

                        /*
                         * If something goes wrong, halve the buffer size
                         * (checking that it does not become smaller than
                         * the current one).
                         */
                        server_sockbufsize /= 2;

                        if ((u_int) sockbufsize >= server_sockbufsize)
                        {
                                server_sockbufsize = sockbufsize;
                                break;
                        }
                }
        }

        /*
         * Let's allocate the packet; this is required in order to put
         * the packet somewhere when extracting data from the socket.
         * Since buffering has already been done in the socket buffer,
         * here we need just a buffer whose size is equal to the
         * largest possible packet message for the snapshot size,
         * namely the length of the message header plus the length
         * of the packet header plus the snapshot length.
         */
        fp->bufsize = sizeof(struct rpcap_header) + sizeof(struct rpcap_pkthdr) + fp->snapshot;

        fp->buffer = (u_char *)malloc(fp->bufsize);
        if (fp->buffer == NULL)
        {
                pcap_fmt_errmsg_for_errno(fp->errbuf, PCAP_ERRBUF_SIZE,
                    errno, "malloc");
                goto error;
        }

        /*
         * The buffer is currently empty.
         */
        fp->bp = fp->buffer;
        fp->cc = 0;

        /* Discard the rest of the message. */
        if (rpcap_discard(pr->rmt_sockctrl, plen, fp->errbuf) == -1)
                goto error;

        /*
         * In case the user does not want to capture RPCAP packets, let's update the filter
         * We have to update it here (instead of sending it into the 'StartCapture' message
         * because when we generate the 'start capture' we do not know (yet) all the ports
         * we're currently using.
         */
        if (pr->rmt_flags & PCAP_OPENFLAG_NOCAPTURE_RPCAP)
        {
                struct bpf_program fcode;

                if (pcap_createfilter_norpcappkt(fp, &fcode) == -1)
                        goto error;

                /* We cannot use 'pcap_setfilter_rpcap' because formally the capture has not been started yet */
                /* (the 'pr->rmt_capstarted' variable will be updated some lines below) */
                if (pcap_updatefilter_remote(fp, &fcode) == -1)
                        goto error;

                pcap_freecode(&fcode);
        }

        pr->rmt_capstarted = 1;
        return 0;

error:
        /*
         * When the connection has been established, we have to close it. So, at the
         * beginning of this function, if an error occur we return immediately with
         * a return NULL; when the connection is established, we have to come here
         * ('goto error;') in order to close everything properly.
         */

        /*
         * Discard the rest of the message.
         * We already reported an error; if this gets an error, just
         * drive on.
         */
        (void)rpcap_discard(pr->rmt_sockctrl, plen, NULL);

error_nodiscard:
        if ((sockdata) && (sockdata != -1))             /* we can be here because sockdata said 'error' */
                sock_close(sockdata, NULL, 0);

        if (!active)
                sock_close(pr->rmt_sockctrl, NULL, 0);

        /*
         * We do not have to call pcap_close() here, because this function is always called
         * by the user in case something bad happens
         */
#if 0
        if (fp)
        {
                pcap_close(fp);
                fp= NULL;
        }
#endif

        return -1;
}

/*
 * This function takes a bpf program and sends it to the other host.
 *
 * This function can be called in two cases:
 * - pcap_startcapture_remote() is called (we have to send the filter
 *   along with the 'start capture' command)
 * - we want to udpate the filter during a capture (i.e. pcap_setfilter()
 *   after the capture has been started)
 *
 * This function serializes the filter into the sending buffer ('sendbuf',
 * passed as a parameter) and return back. It does not send anything on
 * the network.
 *
 * \param fp: the pcap_t descriptor of the device currently opened.
 *
 * \param sendbuf: the buffer on which the serialized data has to copied.
 *
 * \param sendbufidx: it is used to return the abounf of bytes copied into the buffer.
 *
 * \param prog: the bpf program we have to copy.
 *
 * \return '0' if everything is fine, '-1' otherwise. The error message (if one)
 * is returned into the 'errbuf' field of the pcap_t structure.
 */
static int pcap_pack_bpffilter(pcap_t *fp, char *sendbuf, int *sendbufidx, struct bpf_program *prog)
{
        struct rpcap_filter *filter;
        struct rpcap_filterbpf_insn *insn;
        struct bpf_insn *bf_insn;
        struct bpf_program fake_prog;           /* To be used just in case the user forgot to set a filter */
        unsigned int i;

        if (prog->bf_len == 0)  /* No filters have been specified; so, let's apply a "fake" filter */
        {
                if (pcap_compile(fp, &fake_prog, NULL /* buffer */, 1, 0) == -1)
                        return -1;

                prog = &fake_prog;
        }

        filter = (struct rpcap_filter *) sendbuf;

        if (sock_bufferize(NULL, sizeof(struct rpcap_filter), NULL, sendbufidx,
                RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, fp->errbuf, PCAP_ERRBUF_SIZE))
                return -1;

        filter->filtertype = htons(RPCAP_UPDATEFILTER_BPF);
        filter->nitems = htonl((int32)prog->bf_len);

        if (sock_bufferize(NULL, prog->bf_len * sizeof(struct rpcap_filterbpf_insn),
                NULL, sendbufidx, RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, fp->errbuf, PCAP_ERRBUF_SIZE))
                return -1;

        insn = (struct rpcap_filterbpf_insn *) (filter + 1);
        bf_insn = prog->bf_insns;

        for (i = 0; i < prog->bf_len; i++)
        {
                insn->code = htons(bf_insn->code);
                insn->jf = bf_insn->jf;
                insn->jt = bf_insn->jt;
                insn->k = htonl(bf_insn->k);

                insn++;
                bf_insn++;
        }

        return 0;
}

/*
 * This function updates a filter on a remote host.
 *
 * It is called when the user wants to update a filter.
 * In case we're capturing from the network, it sends the filter to our
 * peer.
 * This function is *not* called automatically when the user calls
 * pcap_setfilter().
 * There will be two cases:
 * - the capture has been started: in this case, pcap_setfilter_rpcap()
 *   calls pcap_updatefilter_remote()
 * - the capture has not started yet: in this case, pcap_setfilter_rpcap()
 *   stores the filter into the pcap_t structure, and then the filter is
 *   sent with pcap_startcap().
 *
 * WARNING This function *does not* clear the packet currently into the
 * buffers. Therefore, the user has to expect to receive some packets
 * that are related to the previous filter.  If you want to discard all
 * the packets before applying a new filter, you have to close the
 * current capture session and start a new one.
 *
 * XXX - we really should have pcap_setfilter() always discard packets
 * received with the old filter, and have a separate pcap_setfilter_noflush()
 * function that doesn't discard any packets.
 */
static int pcap_updatefilter_remote(pcap_t *fp, struct bpf_program *prog)
{
        struct pcap_rpcap *pr = fp->priv;       /* structure used when doing a remote live capture */
        char sendbuf[RPCAP_NETBUF_SIZE];        /* temporary buffer in which data to be sent is buffered */
        int sendbufidx = 0;                     /* index which keeps the number of bytes currently buffered */
        struct rpcap_header header;             /* To keep the reply message */

        if (sock_bufferize(NULL, sizeof(struct rpcap_header), NULL, &sendbufidx,
                RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, fp->errbuf, PCAP_ERRBUF_SIZE))
                return -1;

        rpcap_createhdr((struct rpcap_header *) sendbuf,
            pr->protocol_version, RPCAP_MSG_UPDATEFILTER_REQ, 0,
            sizeof(struct rpcap_filter) + prog->bf_len * sizeof(struct rpcap_filterbpf_insn));

        if (pcap_pack_bpffilter(fp, &sendbuf[sendbufidx], &sendbufidx, prog))
                return -1;

        if (sock_send(pr->rmt_sockctrl, sendbuf, sendbufidx, fp->errbuf,
            PCAP_ERRBUF_SIZE) < 0)
                return -1;

        /* Receive and process the reply message header. */
        if (rpcap_process_msg_header(pr->rmt_sockctrl, pr->protocol_version,
            RPCAP_MSG_UPDATEFILTER_REQ, &header, fp->errbuf) == -1)
                return -1;

        /*
         * It shouldn't have any contents; discard it if it does.
         */
        if (rpcap_discard(pr->rmt_sockctrl, header.plen, fp->errbuf) == -1)
                return -1;

        return 0;
}

static void
pcap_save_current_filter_rpcap(pcap_t *fp, const char *filter)
{
        struct pcap_rpcap *pr = fp->priv;       /* structure used when doing a remote live capture */

        /*
         * Check if:
         *  - We are on an remote capture
         *  - we do not want to capture RPCAP traffic
         *
         * If so, we have to save the current filter, because we have to
         * add some piece of stuff later
         */
        if (pr->rmt_clientside &&
            (pr->rmt_flags & PCAP_OPENFLAG_NOCAPTURE_RPCAP))
        {
                if (pr->currentfilter)
                        free(pr->currentfilter);

                if (filter == NULL)
                        filter = "";

                pr->currentfilter = strdup(filter);
        }
}

/*
 * This function sends a filter to a remote host.
 *
 * This function is called when the user wants to set a filter.
 * It sends the filter to our peer.
 * This function is called automatically when the user calls pcap_setfilter().
 *
 * Parameters and return values are exactly the same of pcap_setfilter().
 */
static int pcap_setfilter_rpcap(pcap_t *fp, struct bpf_program *prog)
{
        struct pcap_rpcap *pr = fp->priv;       /* structure used when doing a remote live capture */

        if (!pr->rmt_capstarted)
        {
                /* copy filter into the pcap_t structure */
                if (install_bpf_program(fp, prog) == -1)
                        return -1;
                return 0;
        }

        /* we have to update a filter during run-time */
        if (pcap_updatefilter_remote(fp, prog))
                return -1;

        return 0;
}

/*
 * This function updates the current filter in order not to capture rpcap
 * packets.
 *
 * This function is called *only* when the user wants exclude RPCAP packets
 * related to the current session from the captured packets.
 *
 * \return '0' if everything is fine, '-1' otherwise. The error message (if one)
 * is returned into the 'errbuf' field of the pcap_t structure.
 */
static int pcap_createfilter_norpcappkt(pcap_t *fp, struct bpf_program *prog)
{
        struct pcap_rpcap *pr = fp->priv;       /* structure used when doing a remote live capture */
        int RetVal = 0;

        /* We do not want to capture our RPCAP traffic. So, let's update the filter */
        if (pr->rmt_flags & PCAP_OPENFLAG_NOCAPTURE_RPCAP)
        {
                struct sockaddr_storage saddr;          /* temp, needed to retrieve the network data port chosen on the local machine */
                socklen_t saddrlen;                                     /* temp, needed to retrieve the network data port chosen on the local machine */
                char myaddress[128];
                char myctrlport[128];
                char mydataport[128];
                char peeraddress[128];
                char peerctrlport[128];
                char *newfilter;
                const int newstringsize = 1024;
                size_t currentfiltersize;

                /* Get the name/port of our peer */
                saddrlen = sizeof(struct sockaddr_storage);
                if (getpeername(pr->rmt_sockctrl, (struct sockaddr *) &saddr, &saddrlen) == -1)
                {
                        sock_geterror("getpeername(): ", fp->errbuf, PCAP_ERRBUF_SIZE);
                        return -1;
                }

                if (getnameinfo((struct sockaddr *) &saddr, saddrlen, peeraddress,
                        sizeof(peeraddress), peerctrlport, sizeof(peerctrlport), NI_NUMERICHOST | NI_NUMERICSERV))
                {
                        sock_geterror("getnameinfo(): ", fp->errbuf, PCAP_ERRBUF_SIZE);
                        return -1;
                }

                /* We cannot check the data port, because this is available only in case of TCP sockets */
                /* Get the name/port of the current host */
                if (getsockname(pr->rmt_sockctrl, (struct sockaddr *) &saddr, &saddrlen) == -1)
                {
                        sock_geterror("getsockname(): ", fp->errbuf, PCAP_ERRBUF_SIZE);
                        return -1;
                }

                /* Get the local port the system picked up */
                if (getnameinfo((struct sockaddr *) &saddr, saddrlen, myaddress,
                        sizeof(myaddress), myctrlport, sizeof(myctrlport), NI_NUMERICHOST | NI_NUMERICSERV))
                {
                        sock_geterror("getnameinfo(): ", fp->errbuf, PCAP_ERRBUF_SIZE);
                        return -1;
                }

                /* Let's now check the data port */
                if (getsockname(pr->rmt_sockdata, (struct sockaddr *) &saddr, &saddrlen) == -1)
                {
                        sock_geterror("getsockname(): ", fp->errbuf, PCAP_ERRBUF_SIZE);
                        return -1;
                }

                /* Get the local port the system picked up */
                if (getnameinfo((struct sockaddr *) &saddr, saddrlen, NULL, 0, mydataport, sizeof(mydataport), NI_NUMERICSERV))
                {
                        sock_geterror("getnameinfo(): ", fp->errbuf, PCAP_ERRBUF_SIZE);
                        return -1;
                }

                currentfiltersize = pr->currentfilter ? strlen(pr->currentfilter) : 0;

                newfilter = (char *)malloc(currentfiltersize + newstringsize + 1);

                if (currentfiltersize)
                {
                        pcap_snprintf(newfilter, currentfiltersize + newstringsize,
                                "(%s) and not (host %s and host %s and port %s and port %s) and not (host %s and host %s and port %s)",
                                pr->currentfilter, myaddress, peeraddress, myctrlport, peerctrlport, myaddress, peeraddress, mydataport);
                }
                else
                {
                        pcap_snprintf(newfilter, currentfiltersize + newstringsize,
                                "not (host %s and host %s and port %s and port %s) and not (host %s and host %s and port %s)",
                                myaddress, peeraddress, myctrlport, peerctrlport, myaddress, peeraddress, mydataport);
                }

                newfilter[currentfiltersize + newstringsize] = 0;

                /*
                 * This is only an hack to prevent the save_current_filter
                 * routine, which will be called when we call pcap_compile(),
                 * from saving the modified filter.
                 */
                pr->rmt_clientside = 0;

                if (pcap_compile(fp, prog, newfilter, 1, 0) == -1)
                        RetVal = -1;

                /* Undo the hack. */
                pr->rmt_clientside = 1;

                free(newfilter);
        }

        return RetVal;
}

/*
 * This function sets sampling parameters in the remote host.
 *
 * It is called when the user wants to set activate sampling on the
 * remote host.
 *
 * Sampling parameters are defined into the 'pcap_t' structure.
 *
 * \param p: the pcap_t descriptor of the device currently opened.
 *
 * \return '0' if everything is OK, '-1' is something goes wrong. The
 * error message is returned in the 'errbuf' member of the pcap_t structure.
 */
static int pcap_setsampling_remote(pcap_t *fp)
{
        struct pcap_rpcap *pr = fp->priv;       /* structure used when doing a remote live capture */
        char sendbuf[RPCAP_NETBUF_SIZE];/* temporary buffer in which data to be sent is buffered */
        int sendbufidx = 0;                     /* index which keeps the number of bytes currently buffered */
        struct rpcap_header header;             /* To keep the reply message */
        struct rpcap_sampling *sampling_pars;   /* Structure that is needed to send sampling parameters to the remote host */

        /* If no samping is requested, return 'ok' */
        if (fp->rmt_samp.method == PCAP_SAMP_NOSAMP)
                return 0;

        if (sock_bufferize(NULL, sizeof(struct rpcap_header), NULL,
                &sendbufidx, RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, fp->errbuf, PCAP_ERRBUF_SIZE))
                return -1;

        rpcap_createhdr((struct rpcap_header *) sendbuf,
            pr->protocol_version, RPCAP_MSG_SETSAMPLING_REQ, 0,
            sizeof(struct rpcap_sampling));

        /* Fill the structure needed to open an adapter remotely */
        sampling_pars = (struct rpcap_sampling *) &sendbuf[sendbufidx];

        if (sock_bufferize(NULL, sizeof(struct rpcap_sampling), NULL,
                &sendbufidx, RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, fp->errbuf, PCAP_ERRBUF_SIZE))
                return -1;

        memset(sampling_pars, 0, sizeof(struct rpcap_sampling));

        sampling_pars->method = fp->rmt_samp.method;
        sampling_pars->value = htonl(fp->rmt_samp.value);

        if (sock_send(pr->rmt_sockctrl, sendbuf, sendbufidx, fp->errbuf,
            PCAP_ERRBUF_SIZE) < 0)
                return -1;

        /* Receive and process the reply message header. */
        if (rpcap_process_msg_header(pr->rmt_sockctrl, pr->protocol_version,
            RPCAP_MSG_SETSAMPLING_REQ, &header, fp->errbuf) == -1)
                return -1;

        /*
         * It shouldn't have any contents; discard it if it does.
         */
        if (rpcap_discard(pr->rmt_sockctrl, header.plen, fp->errbuf) == -1)
                return -1;

        return 0;
}

/*********************************************************
 *                                                       *
 * Miscellaneous functions                               *
 *                                                       *
 *********************************************************/

/*
 * This function performs authentication and protocol version
 * negotiation.  It first tries to authenticate with the maximum
 * version we support and, if that fails with an "I don't support
 * that version" error from the server, and the version number in
 * the reply from the server is one we support, tries again with
 * that version.
 *
 * \param sock: the socket we are currently using.
 *
 * \param ver: pointer to variable holding protocol version number to send
 * and to set to the protocol version number in the reply.
 *
 * \param auth: authentication parameters that have to be sent.
 *
 * \param errbuf: a pointer to a user-allocated buffer (of size
 * PCAP_ERRBUF_SIZE) that will contain the error message (in case there
 * is one). It could be a network problem or the fact that the authorization
 * failed.
 *
 * \return '0' if everything is fine, '-1' for an error.  For errors,
 * an error message string is returned in the 'errbuf' variable.
 */
static int rpcap_doauth(SOCKET sockctrl, uint8 *ver, struct pcap_rmtauth *auth, char *errbuf)
{
        int status;

        /*
         * Send authentication to the remote machine.
         *
         * First try with the maximum version number we support.
         */
        *ver = RPCAP_MAX_VERSION;
        status = rpcap_sendauth(sockctrl, ver, auth, errbuf);
        if (status == 0)
        {
                //
                // Success.
                //
                return 0;
        }
        if (status == -1)
        {
                /* Unrecoverable error. */
                return -1;
        }

        /*
         * The server doesn't support the version we used in the initial
         * message, and it sent us back a reply either with the maximum
         * version they do support, or with the version we sent, and we
         * support that version.  *ver has been set to that version; try
         * authenticating again with that version.
         */
        status = rpcap_sendauth(sockctrl, ver, auth, errbuf);
        if (status == 0)
        {
                //
                // Success.
                //
                return 0;
        }
        if (status == -1)
        {
                /* Unrecoverable error. */
                return -1;
        }
        if (status == -2)
        {
                /*
                 * The server doesn't support that version, which
                 * means there is no version we both support, so
                 * this is a fatal error.
                 */
                pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "The server doesn't support any protocol version that we support");
                return -1;
        }
        pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "rpcap_sendauth() returned %d", status);
        return -1;
}

/*
 * This function sends the authentication message.
 *
 * It sends the authentication parameters on the control socket.
 * It is required in order to open the connection with the other end party.
 *
 * \param sock: the socket we are currently using.
 *
 * \param ver: pointer to variable holding protocol version number to send
 * and to set to the protocol version number in the reply.
 *
 * \param auth: authentication parameters that have to be sent.
 *
 * \param errbuf: a pointer to a user-allocated buffer (of size
 * PCAP_ERRBUF_SIZE) that will contain the error message (in case there
 * is one). It could be a network problem or the fact that the authorization
 * failed.
 *
 * \return '0' if everything is fine, '-2' if the server didn't reply with
 * the protocol version we requested but replied with a version we do
 * support, or '-1' for other errors.  For errors, an error message string
 * is returned in the 'errbuf' variable.
 */
static int rpcap_sendauth(SOCKET sock, uint8 *ver, struct pcap_rmtauth *auth, char *errbuf)
{
        char sendbuf[RPCAP_NETBUF_SIZE];        /* temporary buffer in which data that has to be sent is buffered */
        int sendbufidx = 0;                     /* index which keeps the number of bytes currently buffered */
        uint16 length;                          /* length of the payload of this message */
        uint16 errcode;
        struct rpcap_auth *rpauth;
        uint16 auth_type;
        struct rpcap_header header;
        size_t str_length;

        if (auth)
        {
                auth_type = auth->type;

                switch (auth->type)
                {
                case RPCAP_RMTAUTH_NULL:
                        length = sizeof(struct rpcap_auth);
                        break;

                case RPCAP_RMTAUTH_PWD:
                        length = sizeof(struct rpcap_auth);
                        if (auth->username)
                        {
                                str_length = strlen(auth->username);
                                if (str_length > 65535)
                                {
                                        pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "User name is too long (> 65535 bytes)");
                                        return -1;
                                }
                                length += (uint16)str_length;
                        }
                        if (auth->password)
                        {
                                str_length = strlen(auth->password);
                                if (str_length > 65535)
                                {
                                        pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "Password is too long (> 65535 bytes)");
                                        return -1;
                                }
                                length += (uint16)str_length;
                        }
                        break;

                default:
                        pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "Authentication type not recognized.");
                        return -1;
                }
        }
        else
        {
                auth_type = RPCAP_RMTAUTH_NULL;
                length = sizeof(struct rpcap_auth);
        }


        if (sock_bufferize(NULL, sizeof(struct rpcap_header), NULL,
                &sendbufidx, RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, errbuf, PCAP_ERRBUF_SIZE))
                return -1;

        rpcap_createhdr((struct rpcap_header *) sendbuf, *ver,
            RPCAP_MSG_AUTH_REQ, 0, length);

        rpauth = (struct rpcap_auth *) &sendbuf[sendbufidx];

        if (sock_bufferize(NULL, sizeof(struct rpcap_auth), NULL,
                &sendbufidx, RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, errbuf, PCAP_ERRBUF_SIZE))
                return -1;

        memset(rpauth, 0, sizeof(struct rpcap_auth));

        rpauth->type = htons(auth_type);

        if (auth_type == RPCAP_RMTAUTH_PWD)
        {
                if (auth->username)
                        rpauth->slen1 = (uint16)strlen(auth->username);
                else
                        rpauth->slen1 = 0;

                if (sock_bufferize(auth->username, rpauth->slen1, sendbuf,
                        &sendbufidx, RPCAP_NETBUF_SIZE, SOCKBUF_BUFFERIZE, errbuf, PCAP_ERRBUF_SIZE))
                        return -1;

                if (auth->password)
                        rpauth->slen2 = (uint16)strlen(auth->password);
                else
                        rpauth->slen2 = 0;

                if (sock_bufferize(auth->password, rpauth->slen2, sendbuf,
                        &sendbufidx, RPCAP_NETBUF_SIZE, SOCKBUF_BUFFERIZE, errbuf, PCAP_ERRBUF_SIZE))
                        return -1;

                rpauth->slen1 = htons(rpauth->slen1);
                rpauth->slen2 = htons(rpauth->slen2);
        }

        if (sock_send(sock, sendbuf, sendbufidx, errbuf, PCAP_ERRBUF_SIZE) < 0)
                return -1;

        /* Receive the reply */
        if (rpcap_recv_msg_header(sock, &header, errbuf) == -1)
                return -1;

        if (rpcap_check_msg_type(sock, RPCAP_MSG_AUTH_REQ, &header,
            &errcode, errbuf) == -1)
        {
                /* Error message - or something else, which is a protocol error. */
                if (header.type == RPCAP_MSG_ERROR &&
                    errcode == PCAP_ERR_WRONGVER)
                {
                        /*
                         * The server didn't support the version we sent,
                         * and replied with the maximum version it supports
                         * if our version was too big or with the version
                         * we sent if out version was too small.
                         *
                         * Do we also support it?
                         */
                        if (!RPCAP_VERSION_IS_SUPPORTED(header.ver))
                        {
                                /*
                                 * No, so there's no version we both support.
                                 * This is an unrecoverable error.
                                 */
                                pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "The server doesn't support any protocol version that we support");
                                return -1;
                        }

                        /*
                         * OK, use that version, and tell our caller to
                         * try again.
                         */
                        *ver = header.ver;
                        return -2;
                }

                /*
                 * Other error - unrecoverable.
                 */
                return -1;
        }

        /*
         * OK, it's an authentication reply, so they're OK with the
         * protocol version we sent.
         *
         * Discard the rest of it.
         */
        if (rpcap_discard(sock, header.plen, errbuf) == -1)
                return -1;

        return 0;
}

/* We don't currently support non-blocking mode. */
static int
pcap_getnonblock_rpcap(pcap_t *p)
{
        pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
            "Non-blocking mode isn't supported for capturing remotely with rpcap");
        return (-1);
}

static int
pcap_setnonblock_rpcap(pcap_t *p, int nonblock _U_)
{
        pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
            "Non-blocking mode isn't supported for capturing remotely with rpcap");
        return (-1);
}

/*
 * This function opens a remote adapter by opening an RPCAP connection and
 * so on.
 *
 * It does the job of pcap_open_live() for a remote interface; it's called
 * by pcap_open() for remote interfaces.
 *
 * We do not start the capture until pcap_startcapture_remote() is called.
 *
 * This is because, when doing a remote capture, we cannot start capturing
 * data as soon as the 'open adapter' command is sent. Suppose the remote
 * adapter is already overloaded; if we start a capture (which, by default,
 * has a NULL filter) the new traffic can saturate the network.
 *
 * Instead, we want to "open" the adapter, then send a "start capture"
 * command only when we're ready to start the capture.
 * This function does this job: it sends an "open adapter" command
 * (according to the RPCAP protocol), but it does not start the capture.
 *
 * Since the other libpcap functions do not share this way of life, we
 * have to do some dirty things in order to make everything work.
 *
 * \param source: see pcap_open().
 * \param snaplen: see pcap_open().
 * \param flags: see pcap_open().
 * \param read_timeout: see pcap_open().
 * \param auth: see pcap_open().
 * \param errbuf: see pcap_open().
 *
 * \return a pcap_t pointer in case of success, NULL otherwise. In case of
 * success, the pcap_t pointer can be used as a parameter to the following
 * calls (pcap_compile() and so on). In case of problems, errbuf contains
 * a text explanation of error.
 *
 * WARNING: In case we call pcap_compile() and the capture has not yet
 * been started, the filter will be saved into the pcap_t structure,
 * and it will be sent to the other host later (when
 * pcap_startcapture_remote() is called).
 */
pcap_t *pcap_open_rpcap(const char *source, int snaplen, int flags, int read_timeout, struct pcap_rmtauth *auth, char *errbuf)
{
        pcap_t *fp;
        char *source_str;
        struct pcap_rpcap *pr;          /* structure used when doing a remote live capture */
        char host[PCAP_BUF_SIZE], ctrlport[PCAP_BUF_SIZE], iface[PCAP_BUF_SIZE];
        struct activehosts *activeconn;         /* active connection, if there is one */
        int error;                              /* '1' if rpcap_remoteact_getsock returned an error */
        SOCKET sockctrl;
        uint8 protocol_version;                 /* negotiated protocol version */
        int active;
        uint32 plen;
        char sendbuf[RPCAP_NETBUF_SIZE];        /* temporary buffer in which data to be sent is buffered */
        int sendbufidx = 0;                     /* index which keeps the number of bytes currently buffered */
        int retval;                             /* store the return value of the functions */

        /* RPCAP-related variables */
        struct rpcap_header header;             /* header of the RPCAP packet */
        struct rpcap_openreply openreply;       /* open reply message */

        fp = pcap_create_common(errbuf, sizeof (struct pcap_rpcap));
        if (fp == NULL)
        {
                return NULL;
        }
        source_str = strdup(source);
        if (source_str == NULL) {
                pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
                    errno, "malloc");
                return NULL;
        }

        /*
         * Turn a negative snapshot value (invalid), a snapshot value of
         * 0 (unspecified), or a value bigger than the normal maximum
         * value, into the maximum allowed value.
         *
         * If some application really *needs* a bigger snapshot
         * length, we should just increase MAXIMUM_SNAPLEN.
         *
         * XXX - should we leave this up to the remote server to
         * do?
         */
        if (snaplen <= 0 || snaplen > MAXIMUM_SNAPLEN)
                snaplen = MAXIMUM_SNAPLEN;

        fp->opt.device = source_str;
        fp->snapshot = snaplen;
        fp->opt.timeout = read_timeout;
        pr = fp->priv;
        pr->rmt_flags = flags;

        /*
         * determine the type of the source (NULL, file, local, remote)
         * You must have a valid source string even if we're in active mode, because otherwise
         * the call to the following function will fail.
         */
        if (pcap_parsesrcstr(fp->opt.device, &retval, host, ctrlport, iface, errbuf) == -1)
        {
                pcap_close(fp);
                return NULL;
        }

        if (retval != PCAP_SRC_IFREMOTE)
        {
                pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "This function is able to open only remote interfaces");
                pcap_close(fp);
                return NULL;
        }

        /*
         * Warning: this call can be the first one called by the user.
         * For this reason, we have to initialize the WinSock support.
         */
        if (sock_init(errbuf, PCAP_ERRBUF_SIZE) == -1)
        {
                pcap_close(fp);
                return NULL;
        }

        /* Check for active mode */
        activeconn = rpcap_remoteact_getsock(host, &error, errbuf);
        if (activeconn != NULL)
        {
                sockctrl = activeconn->sockctrl;
                protocol_version = activeconn->protocol_version;
                active = 1;
        }
        else
        {
                struct addrinfo hints;                  /* temp, needed to open a socket connection */
                struct addrinfo *addrinfo;              /* temp, needed to open a socket connection */

                if (error)
                {
                        /*
                         * Call failed.
                         */
                        pcap_close(fp);
                        return NULL;
                }

                /*
                 * We're not in active mode; let's try to open a new
                 * control connection.
                 */
                memset(&hints, 0, sizeof(struct addrinfo));
                hints.ai_family = PF_UNSPEC;
                hints.ai_socktype = SOCK_STREAM;

                if (ctrlport[0] == 0)
                {
                        /* the user chose not to specify the port */
                        if (sock_initaddress(host, RPCAP_DEFAULT_NETPORT, &hints, &addrinfo, errbuf, PCAP_ERRBUF_SIZE) == -1)
                        {
                                pcap_close(fp);
                                return NULL;
                        }
                }
                else
                {
                        if (sock_initaddress(host, ctrlport, &hints, &addrinfo, errbuf, PCAP_ERRBUF_SIZE) == -1)
                        {
                                pcap_close(fp);
                                return NULL;
                        }
                }

                if ((sockctrl = sock_open(addrinfo, SOCKOPEN_CLIENT, 0, errbuf, PCAP_ERRBUF_SIZE)) == INVALID_SOCKET)
                {
                        freeaddrinfo(addrinfo);
                        pcap_close(fp);
                        return NULL;
                }

                /* addrinfo is no longer used */
                freeaddrinfo(addrinfo);

                if (rpcap_doauth(sockctrl, &protocol_version, auth, errbuf) == -1)
                {
                        sock_close(sockctrl, NULL, 0);
                        pcap_close(fp);
                        return NULL;
                }
                active = 0;
        }

        /*
         * Now it's time to start playing with the RPCAP protocol
         * RPCAP open command: create the request message
         */
        if (sock_bufferize(NULL, sizeof(struct rpcap_header), NULL,
                &sendbufidx, RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, errbuf, PCAP_ERRBUF_SIZE))
                goto error_nodiscard;

        rpcap_createhdr((struct rpcap_header *) sendbuf, protocol_version,
            RPCAP_MSG_OPEN_REQ, 0, (uint32) strlen(iface));

        if (sock_bufferize(iface, (int) strlen(iface), sendbuf, &sendbufidx,
                RPCAP_NETBUF_SIZE, SOCKBUF_BUFFERIZE, errbuf, PCAP_ERRBUF_SIZE))
                goto error_nodiscard;

        if (sock_send(sockctrl, sendbuf, sendbufidx, errbuf,
            PCAP_ERRBUF_SIZE) < 0)
                goto error_nodiscard;

        /* Receive and process the reply message header. */
        if (rpcap_process_msg_header(sockctrl, protocol_version,
            RPCAP_MSG_OPEN_REQ, &header, errbuf) == -1)
                goto error_nodiscard;
        plen = header.plen;

        /* Read the reply body */
        if (rpcap_recv(sockctrl, (char *)&openreply,
            sizeof(struct rpcap_openreply), &plen, errbuf) == -1)
                goto error;

        /* Discard the rest of the message, if there is any. */
        if (rpcap_discard(pr->rmt_sockctrl, plen, errbuf) == -1)
                goto error_nodiscard;

        /* Set proper fields into the pcap_t struct */
        fp->linktype = ntohl(openreply.linktype);
        fp->tzoff = ntohl(openreply.tzoff);
        pr->rmt_sockctrl = sockctrl;
        pr->protocol_version = protocol_version;
        pr->rmt_clientside = 1;

        /* This code is duplicated from the end of this function */
        fp->read_op = pcap_read_rpcap;
        fp->save_current_filter_op = pcap_save_current_filter_rpcap;
        fp->setfilter_op = pcap_setfilter_rpcap;
        fp->getnonblock_op = pcap_getnonblock_rpcap;
        fp->setnonblock_op = pcap_setnonblock_rpcap;
        fp->stats_op = pcap_stats_rpcap;
#ifdef _WIN32
        fp->stats_ex_op = pcap_stats_ex_rpcap;
#endif
        fp->cleanup_op = pcap_cleanup_rpcap;

        fp->activated = 1;
        return fp;

error:
        /*
         * When the connection has been established, we have to close it. So, at the
         * beginning of this function, if an error occur we return immediately with
         * a return NULL; when the connection is established, we have to come here
         * ('goto error;') in order to close everything properly.
         */

        /*
         * Discard the rest of the message.
         * We already reported an error; if this gets an error, just
         * drive on.
         */
        (void)rpcap_discard(pr->rmt_sockctrl, plen, NULL);

error_nodiscard:
        if (!active)
                sock_close(sockctrl, NULL, 0);

        pcap_close(fp);
        return NULL;
}

/* String identifier to be used in the pcap_findalldevs_ex() */
#define PCAP_TEXT_SOURCE_ADAPTER "Network adapter"
/* String identifier to be used in the pcap_findalldevs_ex() */
#define PCAP_TEXT_SOURCE_ON_REMOTE_HOST "on remote node"

static void
freeaddr(struct pcap_addr *addr)
{
        free(addr->addr);
        free(addr->netmask);
        free(addr->broadaddr);
        free(addr->dstaddr);
        free(addr);
}

int
pcap_findalldevs_ex_remote(char *source, struct pcap_rmtauth *auth, pcap_if_t **alldevs, char *errbuf)
{
        struct activehosts *activeconn; /* active connection, if there is one */
        int error;                      /* '1' if rpcap_remoteact_getsock returned an error */
        uint8 protocol_version;         /* protocol version */
        SOCKET sockctrl;                /* socket descriptor of the control connection */
        uint32 plen;
        struct rpcap_header header;     /* structure that keeps the general header of the rpcap protocol */
        int i, j;               /* temp variables */
        int nif;                /* Number of interfaces listed */
        int active;                     /* 'true' if we the other end-party is in active mode */
        int type;
        char host[PCAP_BUF_SIZE], port[PCAP_BUF_SIZE];
        char tmpstring[PCAP_BUF_SIZE + 1];              /* Needed to convert names and descriptions from 'old' syntax to the 'new' one */
        pcap_if_t *lastdev;     /* Last device in the pcap_if_t list */
        pcap_if_t *dev;         /* Device we're adding to the pcap_if_t list */

        /* List starts out empty. */
        (*alldevs) = NULL;
        lastdev = NULL;

        /* Retrieve the needed data for getting adapter list */
        if (pcap_parsesrcstr(source, &type, host, port, NULL, errbuf) == -1)
                return -1;

        /* Warning: this call can be the first one called by the user. */
        /* For this reason, we have to initialize the WinSock support. */
        if (sock_init(errbuf, PCAP_ERRBUF_SIZE) == -1)
                return -1;

        /* Check for active mode */
        activeconn = rpcap_remoteact_getsock(host, &error, errbuf);
        if (activeconn != NULL)
        {
                sockctrl = activeconn->sockctrl;
                protocol_version = activeconn->protocol_version;
                active = 1;
        }
        else
        {
                struct addrinfo hints;          /* temp variable needed to resolve hostnames into to socket representation */
                struct addrinfo *addrinfo;      /* temp variable needed to resolve hostnames into to socket representation */

                if (error)
                {
                        /*
                         * Call failed.
                         */
                        return -1;
                }

                /*
                 * We're not in active mode; let's try to open a new
                 * control connection.
                 */
                memset(&hints, 0, sizeof(struct addrinfo));
                hints.ai_family = PF_UNSPEC;
                hints.ai_socktype = SOCK_STREAM;

                if (port[0] == 0)
                {
                        /* the user chose not to specify the port */
                        if (sock_initaddress(host, RPCAP_DEFAULT_NETPORT, &hints, &addrinfo, errbuf, PCAP_ERRBUF_SIZE) == -1)
                                return -1;
                }
                else
                {
                        if (sock_initaddress(host, port, &hints, &addrinfo, errbuf, PCAP_ERRBUF_SIZE) == -1)
                                return -1;
                }

                if ((sockctrl = sock_open(addrinfo, SOCKOPEN_CLIENT, 0, errbuf, PCAP_ERRBUF_SIZE)) == INVALID_SOCKET)
                {
                        freeaddrinfo(addrinfo);
                        return -1;
                }

                /* addrinfo is no longer used */
                freeaddrinfo(addrinfo);
                addrinfo = NULL;

                if (rpcap_doauth(sockctrl, &protocol_version, auth, errbuf) == -1)
                {
                        sock_close(sockctrl, NULL, 0);
                        return -1;
                }
                active = 0;
        }

        /* RPCAP findalldevs command */
        rpcap_createhdr(&header, protocol_version, RPCAP_MSG_FINDALLIF_REQ,
            0, 0);

        if (sock_send(sockctrl, (char *)&header, sizeof(struct rpcap_header),
            errbuf, PCAP_ERRBUF_SIZE) < 0)
                goto error_nodiscard;

        /* Receive and process the reply message header. */
        if (rpcap_process_msg_header(sockctrl, protocol_version,
            RPCAP_MSG_FINDALLIF_REQ, &header, errbuf) == -1)
                goto error_nodiscard;

        plen = header.plen;

        /* read the number of interfaces */
        nif = ntohs(header.value);

        /* loop until all interfaces have been received */
        for (i = 0; i < nif; i++)
        {
                struct rpcap_findalldevs_if findalldevs_if;
                char tmpstring2[PCAP_BUF_SIZE + 1];             /* Needed to convert names and descriptions from 'old' syntax to the 'new' one */
                size_t stringlen;
                struct pcap_addr *addr, *prevaddr;

                tmpstring2[PCAP_BUF_SIZE] = 0;

                /* receive the findalldevs structure from remote host */
                if (rpcap_recv(sockctrl, (char *)&findalldevs_if,
                    sizeof(struct rpcap_findalldevs_if), &plen, errbuf) == -1)
                        goto error;

                findalldevs_if.namelen = ntohs(findalldevs_if.namelen);
                findalldevs_if.desclen = ntohs(findalldevs_if.desclen);
                findalldevs_if.naddr = ntohs(findalldevs_if.naddr);

                /* allocate the main structure */
                dev = (pcap_if_t *)malloc(sizeof(pcap_if_t));
                if (dev == NULL)
                {
                        pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
                            errno, "malloc() failed");
                        goto error;
                }

                /* Initialize the structure to 'zero' */
                memset(dev, 0, sizeof(pcap_if_t));

                /* Append it to the list. */
                if (lastdev == NULL)
                {
                        /*
                         * List is empty, so it's also the first device.
                         */
                        *alldevs = dev;
                }
                else
                {
                        /*
                         * Append after the last device.
                         */
                        lastdev->next = dev;
                }
                /* It's now the last device. */
                lastdev = dev;

                /* allocate mem for name and description */
                if (findalldevs_if.namelen)
                {

                        if (findalldevs_if.namelen >= sizeof(tmpstring))
                        {
                                pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "Interface name too long");
                                goto error;
                        }

                        /* Retrieve adapter name */
                        if (rpcap_recv(sockctrl, tmpstring,
                            findalldevs_if.namelen, &plen, errbuf) == -1)
                                goto error;

                        tmpstring[findalldevs_if.namelen] = 0;

                        /* Create the new device identifier */
                        if (pcap_createsrcstr(tmpstring2, PCAP_SRC_IFREMOTE, host, port, tmpstring, errbuf) == -1)
                                return -1;

                        stringlen = strlen(tmpstring2);

                        dev->name = (char *)malloc(stringlen + 1);
                        if (dev->name == NULL)
                        {
                                pcap_fmt_errmsg_for_errno(errbuf,
                                    PCAP_ERRBUF_SIZE, errno, "malloc() failed");
                                goto error;
                        }

                        /* Copy the new device name into the correct memory location */
                        strlcpy(dev->name, tmpstring2, stringlen + 1);
                }

                if (findalldevs_if.desclen)
                {
                        if (findalldevs_if.desclen >= sizeof(tmpstring))
                        {
                                pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "Interface description too long");
                                goto error;
                        }

                        /* Retrieve adapter description */
                        if (rpcap_recv(sockctrl, tmpstring,
                            findalldevs_if.desclen, &plen, errbuf) == -1)
                                goto error;

                        tmpstring[findalldevs_if.desclen] = 0;

                        pcap_snprintf(tmpstring2, sizeof(tmpstring2) - 1, "%s '%s' %s %s", PCAP_TEXT_SOURCE_ADAPTER,
                                tmpstring, PCAP_TEXT_SOURCE_ON_REMOTE_HOST, host);

                        stringlen = strlen(tmpstring2);

                        dev->description = (char *)malloc(stringlen + 1);

                        if (dev->description == NULL)
                        {
                                pcap_fmt_errmsg_for_errno(errbuf,
                                    PCAP_ERRBUF_SIZE, errno, "malloc() failed");
                                goto error;
                        }

                        /* Copy the new device description into the correct memory location */
                        strlcpy(dev->description, tmpstring2, stringlen + 1);
                }

                dev->flags = ntohl(findalldevs_if.flags);

                prevaddr = NULL;
                /* loop until all addresses have been received */
                for (j = 0; j < findalldevs_if.naddr; j++)
                {
                        struct rpcap_findalldevs_ifaddr ifaddr;

                        /* Retrieve the interface addresses */
                        if (rpcap_recv(sockctrl, (char *)&ifaddr,
                            sizeof(struct rpcap_findalldevs_ifaddr),
                            &plen, errbuf) == -1)
                                goto error;

                        /*
                         * Deserialize all the address components.
                         */
                        addr = (struct pcap_addr *) malloc(sizeof(struct pcap_addr));
                        if (addr == NULL)
                        {
                                pcap_fmt_errmsg_for_errno(errbuf,
                                    PCAP_ERRBUF_SIZE, errno, "malloc() failed");
                                goto error;
                        }
                        addr->next = NULL;
                        addr->addr = NULL;
                        addr->netmask = NULL;
                        addr->broadaddr = NULL;
                        addr->dstaddr = NULL;

                        if (rpcap_deseraddr(&ifaddr.addr,
                                (struct sockaddr_storage **) &addr->addr, errbuf) == -1)
                        {
                                freeaddr(addr);
                                goto error;
                        }
                        if (rpcap_deseraddr(&ifaddr.netmask,
                                (struct sockaddr_storage **) &addr->netmask, errbuf) == -1)
                        {
                                freeaddr(addr);
                                goto error;
                        }
                        if (rpcap_deseraddr(&ifaddr.broadaddr,
                                (struct sockaddr_storage **) &addr->broadaddr, errbuf) == -1)
                        {
                                freeaddr(addr);
                                goto error;
                        }
                        if (rpcap_deseraddr(&ifaddr.dstaddr,
                                (struct sockaddr_storage **) &addr->dstaddr, errbuf) == -1)
                        {
                                freeaddr(addr);
                                goto error;
                        }

                        if ((addr->addr == NULL) && (addr->netmask == NULL) &&
                                (addr->broadaddr == NULL) && (addr->dstaddr == NULL))
                        {
                                /*
                                 * None of the addresses are IPv4 or IPv6
                                 * addresses, so throw this entry away.
                                 */
                                free(addr);
                        }
                        else
                        {
                                /*
                                 * Add this entry to the list.
                                 */
                                if (prevaddr == NULL)
                                {
                                        dev->addresses = addr;
                                }
                                else
                                {
                                        prevaddr->next = addr;
                                }
                                prevaddr = addr;
                        }
                }
        }

        /* Discard the rest of the message. */
        if (rpcap_discard(sockctrl, plen, errbuf) == 1)
                return -1;

        /* Control connection has to be closed only in case the remote machine is in passive mode */
        if (!active)
        {
                /* DO not send RPCAP_CLOSE, since we did not open a pcap_t; no need to free resources */
                if (sock_close(sockctrl, errbuf, PCAP_ERRBUF_SIZE))
                        return -1;
        }

        /* To avoid inconsistencies in the number of sock_init() */
        sock_cleanup();

        return 0;

error:
        /*
         * In case there has been an error, I don't want to overwrite it with a new one
         * if the following call fails. I want to return always the original error.
         *
         * Take care: this connection can already be closed when we try to close it.
         * This happens because a previous error in the rpcapd, which requested to
         * closed the connection. In that case, we already recognized that into the
         * rpspck_isheaderok() and we already acknowledged the closing.
         * In that sense, this call is useless here (however it is needed in case
         * the client generates the error).
         *
         * Checks if all the data has been read; if not, discard the data in excess
         */
        (void) rpcap_discard(sockctrl, plen, NULL);

error_nodiscard:
        /* Control connection has to be closed only in case the remote machine is in passive mode */
        if (!active)
                sock_close(sockctrl, NULL, 0);

        /* To avoid inconsistencies in the number of sock_init() */
        sock_cleanup();

        /* Free whatever interfaces we've allocated. */
        pcap_freealldevs(*alldevs);

        return -1;
}

/*
 * Active mode routines.
 *
 * The old libpcap API is somewhat ugly, and makes active mode difficult
 * to implement; we provide some APIs for it that work only with rpcap.
 */

SOCKET pcap_remoteact_accept(const char *address, const char *port, const char *hostlist, char *connectinghost, struct pcap_rmtauth *auth, char *errbuf)
{
        /* socket-related variables */
        struct addrinfo hints;                  /* temporary struct to keep settings needed to open the new socket */
        struct addrinfo *addrinfo;              /* keeps the addrinfo chain; required to open a new socket */
        struct sockaddr_storage from;   /* generic sockaddr_storage variable */
        socklen_t fromlen;                              /* keeps the length of the sockaddr_storage variable */
        SOCKET sockctrl;                                /* keeps the main socket identifier */
        uint8 protocol_version;                 /* negotiated protocol version */
        struct activehosts *temp, *prev;        /* temp var needed to scan he host list chain */

        *connectinghost = 0;            /* just in case */

        /* Prepare to open a new server socket */
        memset(&hints, 0, sizeof(struct addrinfo));
        /* WARNING Currently it supports only ONE socket family among ipv4 and IPv6  */
        hints.ai_family = AF_INET;              /* PF_UNSPEC to have both IPv4 and IPv6 server */
        hints.ai_flags = AI_PASSIVE;    /* Ready to a bind() socket */
        hints.ai_socktype = SOCK_STREAM;

        /* Warning: this call can be the first one called by the user. */
        /* For this reason, we have to initialize the WinSock support. */
        if (sock_init(errbuf, PCAP_ERRBUF_SIZE) == -1)
                return -1;

        /* Do the work */
        if ((port == NULL) || (port[0] == 0))
        {
                if (sock_initaddress(address, RPCAP_DEFAULT_NETPORT_ACTIVE, &hints, &addrinfo, errbuf, PCAP_ERRBUF_SIZE) == -1)
                {
                        SOCK_ASSERT(errbuf, 1);
                        return -2;
                }
        }
        else
        {
                if (sock_initaddress(address, port, &hints, &addrinfo, errbuf, PCAP_ERRBUF_SIZE) == -1)
                {
                        SOCK_ASSERT(errbuf, 1);
                        return -2;
                }
        }


        if ((sockmain = sock_open(addrinfo, SOCKOPEN_SERVER, 1, errbuf, PCAP_ERRBUF_SIZE)) == INVALID_SOCKET)
        {
                SOCK_ASSERT(errbuf, 1);
                freeaddrinfo(addrinfo);
                return -2;
        }
        freeaddrinfo(addrinfo);

        /* Connection creation */
        fromlen = sizeof(struct sockaddr_storage);

        sockctrl = accept(sockmain, (struct sockaddr *) &from, &fromlen);

        /* We're not using sock_close, since we do not want to send a shutdown */
        /* (which is not allowed on a non-connected socket) */
        closesocket(sockmain);
        sockmain = 0;

        if (sockctrl == INVALID_SOCKET)
        {
                sock_geterror("accept(): ", errbuf, PCAP_ERRBUF_SIZE);
                return -2;
        }

        /* Get the numeric for of the name of the connecting host */
        if (getnameinfo((struct sockaddr *) &from, fromlen, connectinghost, RPCAP_HOSTLIST_SIZE, NULL, 0, NI_NUMERICHOST))
        {
                sock_geterror("getnameinfo(): ", errbuf, PCAP_ERRBUF_SIZE);
                rpcap_senderror(sockctrl, 0, PCAP_ERR_REMOTEACCEPT, errbuf, NULL);
                sock_close(sockctrl, NULL, 0);
                return -1;
        }

        /* checks if the connecting host is among the ones allowed */
        if (sock_check_hostlist((char *)hostlist, RPCAP_HOSTLIST_SEP, &from, errbuf, PCAP_ERRBUF_SIZE) < 0)
        {
                rpcap_senderror(sockctrl, 0, PCAP_ERR_REMOTEACCEPT, errbuf, NULL);
                sock_close(sockctrl, NULL, 0);
                return -1;
        }

        /*
         * Send authentication to the remote machine.
         */
        if (rpcap_doauth(sockctrl, &protocol_version, auth, errbuf) == -1)
        {
                /* Unrecoverable error. */
                rpcap_senderror(sockctrl, 0, PCAP_ERR_REMOTEACCEPT, errbuf, NULL);
                sock_close(sockctrl, NULL, 0);
                return -3;
        }

        /* Checks that this host does not already have a cntrl connection in place */

        /* Initialize pointers */
        temp = activeHosts;
        prev = NULL;

        while (temp)
        {
                /* This host already has an active connection in place, so I don't have to update the host list */
                if (sock_cmpaddr(&temp->host, &from) == 0)
                        return sockctrl;

                prev = temp;
                temp = temp->next;
        }

        /* The host does not exist in the list; so I have to update the list */
        if (prev)
        {
                prev->next = (struct activehosts *) malloc(sizeof(struct activehosts));
                temp = prev->next;
        }
        else
        {
                activeHosts = (struct activehosts *) malloc(sizeof(struct activehosts));
                temp = activeHosts;
        }

        if (temp == NULL)
        {
                pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
                    errno, "malloc() failed");
                rpcap_senderror(sockctrl, protocol_version, PCAP_ERR_REMOTEACCEPT, errbuf, NULL);
                sock_close(sockctrl, NULL, 0);
                return -1;
        }

        memcpy(&temp->host, &from, fromlen);
        temp->sockctrl = sockctrl;
        temp->protocol_version = protocol_version;
        temp->next = NULL;

        return sockctrl;
}

int pcap_remoteact_close(const char *host, char *errbuf)
{
        struct activehosts *temp, *prev;        /* temp var needed to scan the host list chain */
        struct addrinfo hints, *addrinfo, *ai_next;     /* temp var needed to translate between hostname to its address */
        int retval;

        temp = activeHosts;
        prev = NULL;

        /* retrieve the network address corresponding to 'host' */
        addrinfo = NULL;
        memset(&hints, 0, sizeof(struct addrinfo));
        hints.ai_family = PF_UNSPEC;
        hints.ai_socktype = SOCK_STREAM;

        retval = getaddrinfo(host, "0", &hints, &addrinfo);
        if (retval != 0)
        {
                pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "getaddrinfo() %s", gai_strerror(retval));
                return -1;
        }

        while (temp)
        {
                ai_next = addrinfo;
                while (ai_next)
                {
                        if (sock_cmpaddr(&temp->host, (struct sockaddr_storage *) ai_next->ai_addr) == 0)
                        {
                                struct rpcap_header header;
                                int status = 0;

                                /* Close this connection */
                                rpcap_createhdr(&header, temp->protocol_version,
                                    RPCAP_MSG_CLOSE, 0, 0);

                                /*
                                 * Don't check for errors, since we're
                                 * just cleaning up.
                                 */
                                if (sock_send(temp->sockctrl,
                                    (char *)&header,
                                    sizeof(struct rpcap_header), errbuf,
                                    PCAP_ERRBUF_SIZE) < 0)
                                {
                                        /*
                                         * Let that error be the one we
                                         * report.
                                         */
                                        (void)sock_close(temp->sockctrl, NULL,
                                           0);
                                        status = -1;
                                }
                                else
                                {
                                        if (sock_close(temp->sockctrl, errbuf,
                                           PCAP_ERRBUF_SIZE) == -1)
                                                status = -1;
                                }

                                /*
                                 * Remove the host from the list of active
                                 * hosts.
                                 */
                                if (prev)
                                        prev->next = temp->next;
                                else
                                        activeHosts = temp->next;

                                freeaddrinfo(addrinfo);

                                free(temp);

                                /* To avoid inconsistencies in the number of sock_init() */
                                sock_cleanup();

                                return status;
                        }

                        ai_next = ai_next->ai_next;
                }
                prev = temp;
                temp = temp->next;
        }

        if (addrinfo)
                freeaddrinfo(addrinfo);

        /* To avoid inconsistencies in the number of sock_init() */
        sock_cleanup();

        pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "The host you want to close the active connection is not known");
        return -1;
}

void pcap_remoteact_cleanup(void)
{
        /* Very dirty, but it works */
        if (sockmain)
        {
                closesocket(sockmain);

                /* To avoid inconsistencies in the number of sock_init() */
                sock_cleanup();
        }

}

int pcap_remoteact_list(char *hostlist, char sep, int size, char *errbuf)
{
        struct activehosts *temp;       /* temp var needed to scan the host list chain */
        size_t len;
        char hoststr[RPCAP_HOSTLIST_SIZE + 1];

        temp = activeHosts;

        len = 0;
        *hostlist = 0;

        while (temp)
        {
                /*int sock_getascii_addrport(const struct sockaddr_storage *sockaddr, char *address, int addrlen, char *port, int portlen, int flags, char *errbuf, int errbuflen) */

                /* Get the numeric form of the name of the connecting host */
                if (sock_getascii_addrport((struct sockaddr_storage *) &temp->host, hoststr,
                        RPCAP_HOSTLIST_SIZE, NULL, 0, NI_NUMERICHOST, errbuf, PCAP_ERRBUF_SIZE) != -1)
                        /*      if (getnameinfo( (struct sockaddr *) &temp->host, sizeof (struct sockaddr_storage), hoststr, */
                        /*              RPCAP_HOSTLIST_SIZE, NULL, 0, NI_NUMERICHOST) ) */
                {
                        /*      sock_geterror("getnameinfo(): ", errbuf, PCAP_ERRBUF_SIZE); */
                        return -1;
                }

                len = len + strlen(hoststr) + 1 /* the separator */;

                if ((size < 0) || (len >= (size_t)size))
                {
                        pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "The string you provided is not able to keep "
                                "the hostnames for all the active connections");
                        return -1;
                }

                strlcat(hostlist, hoststr, PCAP_ERRBUF_SIZE);
                hostlist[len - 1] = sep;
                hostlist[len] = 0;

                temp = temp->next;
        }

        return 0;
}

/*
 * Receive the header of a message.
 */
static int rpcap_recv_msg_header(SOCKET sock, struct rpcap_header *header, char *errbuf)
{
        int nrecv;

        nrecv = sock_recv(sock, (char *) header, sizeof(struct rpcap_header),
            SOCK_RECEIVEALL_YES|SOCK_EOF_IS_ERROR, errbuf,
            PCAP_ERRBUF_SIZE);
        if (nrecv == -1)
        {
                /* Network error. */
                return -1;
        }
        header->plen = ntohl(header->plen);
        return 0;
}

/*
 * Make sure the protocol version of a received message is what we were
 * expecting.
 */
static int rpcap_check_msg_ver(SOCKET sock, uint8 expected_ver, struct rpcap_header *header, char *errbuf)
{
        /*
         * Did the server specify the version we negotiated?
         */
        if (header->ver != expected_ver)
        {
                /*
                 * Discard the rest of the message.
                 */
                if (rpcap_discard(sock, header->plen, errbuf) == -1)
                        return -1;

                /*
                 * Tell our caller that it's not the negotiated version.
                 */
                if (errbuf != NULL)
                {
                        pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
                            "Server sent us a message with version %u when we were expecting %u",
                            header->ver, expected_ver);
                }
                return -1;
        }
        return 0;
}

/*
 * Check the message type of a received message, which should either be
 * the expected message type or RPCAP_MSG_ERROR.
 */
static int rpcap_check_msg_type(SOCKET sock, uint8 request_type, struct rpcap_header *header, uint16 *errcode, char *errbuf)
{
        const char *request_type_string;
        const char *msg_type_string;

        /*
         * What type of message is it?
         */
        if (header->type == RPCAP_MSG_ERROR)
        {
                /*
                 * The server reported an error.
                 * Hand that error back to our caller.
                 */
                *errcode = ntohs(header->value);
                rpcap_msg_err(sock, header->plen, errbuf);
                return -1;
        }

        *errcode = 0;

        /*
         * For a given request type value, the expected reply type value
         * is the request type value with ORed with RPCAP_MSG_IS_REPLY.
         */
        if (header->type != (request_type | RPCAP_MSG_IS_REPLY))
        {
                /*
                 * This isn't a reply to the request we sent.
                 */

                /*
                 * Discard the rest of the message.
                 */
                if (rpcap_discard(sock, header->plen, errbuf) == -1)
                        return -1;

                /*
                 * Tell our caller about it.
                 */
                request_type_string = rpcap_msg_type_string(request_type);
                msg_type_string = rpcap_msg_type_string(header->type);
                if (errbuf != NULL)
                {
                        if (request_type_string == NULL)
                        {
                                /* This should not happen. */
                                pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
                                    "rpcap_check_msg_type called for request message with type %u",
                                    request_type);
                                return -1;
                        }
                        if (msg_type_string != NULL)
                                pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
                                    "%s message received in response to a %s message",
                                    msg_type_string, request_type_string);
                        else
                                pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
                                    "Message of unknown type %u message received in response to a %s request",
                                    header->type, request_type_string);
                }
                return -1;
        }
        
        return 0;
}

/*
 * Receive and process the header of a message.
 */
static int rpcap_process_msg_header(SOCKET sock, uint8 expected_ver, uint8 request_type, struct rpcap_header *header, char *errbuf)
{
        uint16 errcode;

        if (rpcap_recv_msg_header(sock, header, errbuf) == -1)
        {
                /* Network error. */
                return -1;
        }

        /*
         * Did the server specify the version we negotiated?
         */
        if (rpcap_check_msg_ver(sock, expected_ver, header, errbuf) == -1)
                return -1;

        /*
         * Check the message type.
         */
        return rpcap_check_msg_type(sock, request_type, header,
            &errcode, errbuf);
}

/*
 * Read data from a message.
 * If we're trying to read more data that remains, puts an error
 * message into errmsgbuf and returns -2.  Otherwise, tries to read
 * the data and, if that succeeds, subtracts the amount read from
 * the number of bytes of data that remains.
 * Returns 0 on success, logs a message and returns -1 on a network
 * error.
 */
static int rpcap_recv(SOCKET sock, void *buffer, size_t toread, uint32 *plen, char *errbuf)
{
        int nread;

        if (toread > *plen)
        {
                /* The server sent us a bad message */
                pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "Message payload is too short");
                return -1;
        }
        nread = sock_recv(sock, buffer, toread,
            SOCK_RECEIVEALL_YES|SOCK_EOF_IS_ERROR, errbuf, PCAP_ERRBUF_SIZE);
        if (nread == -1)
        {
                return -1;
        }
        *plen -= nread;
        return 0;
}

/*
 * This handles the RPCAP_MSG_ERROR message.
 */
static void rpcap_msg_err(SOCKET sockctrl, uint32 plen, char *remote_errbuf)
{
        char errbuf[PCAP_ERRBUF_SIZE];

        if (plen >= PCAP_ERRBUF_SIZE)
        {
                /*
                 * Message is too long; just read as much of it as we
                 * can into the buffer provided, and discard the rest.
                 */
                if (sock_recv(sockctrl, remote_errbuf, PCAP_ERRBUF_SIZE - 1,
                    SOCK_RECEIVEALL_YES|SOCK_EOF_IS_ERROR, errbuf,
                    PCAP_ERRBUF_SIZE) == -1)
                {
                        // Network error.
                        pcap_snprintf(remote_errbuf, PCAP_ERRBUF_SIZE, "Read of error message from client failed: %s", errbuf);
                        return;
                }

                /*
                 * Null-terminate it.
                 */
                remote_errbuf[PCAP_ERRBUF_SIZE - 1] = '\0';

                /*
                 * Throw away the rest.
                 */
                (void)rpcap_discard(sockctrl, plen - (PCAP_ERRBUF_SIZE - 1), remote_errbuf);
        }
        else if (plen == 0)
        {
                /* Empty error string. */
                remote_errbuf[0] = '\0';
        }
        else
        {
                if (sock_recv(sockctrl, remote_errbuf, plen,
                    SOCK_RECEIVEALL_YES|SOCK_EOF_IS_ERROR, errbuf,
                    PCAP_ERRBUF_SIZE) == -1)
                {
                        // Network error.
                        pcap_snprintf(remote_errbuf, PCAP_ERRBUF_SIZE, "Read of error message from client failed: %s", errbuf);
                        return;
                }

                /*
                 * Null-terminate it.
                 */
                remote_errbuf[plen] = '\0';
        }
}

/*
 * Discard data from a connection.
 * Mostly used to discard wrong-sized messages.
 * Returns 0 on success, logs a message and returns -1 on a network
 * error.
 */
static int rpcap_discard(SOCKET sock, uint32 len, char *errbuf)
{
        if (len != 0)
        {
                if (sock_discard(sock, len, errbuf, PCAP_ERRBUF_SIZE) == -1)
                {
                        // Network error.
                        return -1;
                }
        }
        return 0;
}

/*
 * Read bytes into the pcap_t's buffer until we have the specified
 * number of bytes read or we get an error or interrupt indication.
 */
static int rpcap_read_packet_msg(SOCKET sock, pcap_t *p, size_t size)
{
        u_char *bp;
        int cc;
        int bytes_read;

        bp = p->bp;
        cc = p->cc;

        /*
         * Loop until we have the amount of data requested or we get
         * an error or interrupt.
         */
        while ((size_t)cc < size)
        {
                /*
                 * We haven't read all of the packet header yet.
                 * Read what remains, which could be all of it.
                 */
                bytes_read = sock_recv(sock, bp, size - cc,
                    SOCK_RECEIVEALL_NO|SOCK_EOF_IS_ERROR, p->errbuf,
                    PCAP_ERRBUF_SIZE);
                if (bytes_read == -1)
                {
                        /*
                         * Network error.  Update the read pointer and
                         * byte count, and return an error indication.
                         */
                        p->bp = bp;
                        p->cc = cc;
                        return -1;
                }
                if (bytes_read == -3)
                {
                        /*
                         * Interrupted receive.  Update the read
                         * pointer and byte count, and return
                         * an interrupted indication.
                         */
                        p->bp = bp;
                        p->cc = cc;
                        return -3;
                }
                if (bytes_read == 0)
                {
                        /*
                         * EOF - server terminated the connection.
                         * Update the read pointer and byte count, and
                         * return an error indication.
                         */
                        pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                            "The server terminated the connection.");
                        return -1;
                }
                bp += bytes_read;
                cc += bytes_read;
        }
        p->bp = bp;
        p->cc = cc;
        return 0;
}