[libpcap] / pcap-nit.c

/*
 * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that: (1) source code distributions
 * retain the above copyright notice and this paragraph in its entirety, (2)
 * distributions including binary code include the above copyright notice and
 * this paragraph in its entirety in the documentation or other materials
 * provided with the distribution, and (3) all advertising materials mentioning
 * features or use of this software display the following acknowledgement:
 * ``This product includes software developed by the University of California,
 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
 * the University 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */
#ifndef lint
static const char rcsid[] _U_ =
    "@(#) $Header: /tcpdump/master/libpcap/pcap-nit.c,v 1.58.2.2 2008-02-02 20:58:31 guy Exp $ (LBL)";
#endif

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <sys/types.h>
#include <sys/time.h>
#include <sys/timeb.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/socket.h>

#include <net/if.h>
#include <net/nit.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/if_ether.h>
#include <netinet/ip_var.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>
#include <netinet/tcp.h>
#include <netinet/tcpip.h>

#include <ctype.h>
#include <errno.h>
#include <stdio.h>

#include "pcap-int.h"

#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif

/*
 * The chunk size for NIT.  This is the amount of buffering
 * done for read calls.
 */
#define CHUNKSIZE (2*1024)

/*
 * The total buffer space used by NIT.
 */
#define BUFSPACE (4*CHUNKSIZE)

/* Forwards */
static int nit_setflags(int, int, int, char *);

static int
pcap_stats_nit(pcap_t *p, struct pcap_stat *ps)
{

        /*
         * "ps_recv" counts packets handed to the filter, not packets
         * that passed the filter.  As filtering is done in userland,
         * this does not include packets dropped because we ran out
         * of buffer space.
         *
         * "ps_drop" presumably counts packets dropped by the socket
         * because of flow control requirements or resource exhaustion;
         * it doesn't count packets dropped by the interface driver.
         * As filtering is done in userland, it counts packets regardless
         * of whether they would've passed the filter.
         *
         * These statistics don't include packets not yet read from the
         * kernel by libpcap or packets not yet read from libpcap by the
         * application.
         */
        *ps = p->md.stat;
        return (0);
}

static int
pcap_read_nit(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
{
        register int cc, n;
        register u_char *bp, *cp, *ep;
        register struct nit_hdr *nh;
        register int caplen;

        cc = p->cc;
        if (cc == 0) {
                cc = read(p->fd, (char *)p->buffer, p->bufsize);
                if (cc < 0) {
                        if (errno == EWOULDBLOCK)
                                return (0);
                        snprintf(p->errbuf, sizeof(p->errbuf), "pcap_read: %s",
                                pcap_strerror(errno));
                        return (-1);
                }
                bp = p->buffer;
        } else
                bp = p->bp;

        /*
         * Loop through each packet.  The increment expression
         * rounds up to the next int boundary past the end of
         * the previous packet.
         */
        n = 0;
        ep = bp + cc;
        while (bp < ep) {
                /*
                 * Has "pcap_breakloop()" been called?
                 * If so, return immediately - if we haven't read any
                 * packets, clear the flag and return -2 to indicate
                 * that we were told to break out of the loop, otherwise
                 * leave the flag set, so that the *next* call will break
                 * out of the loop without having read any packets, and
                 * return the number of packets we've processed so far.
                 */
                if (p->break_loop) {
                        if (n == 0) {
                                p->break_loop = 0;
                                return (-2);
                        } else {
                                p->cc = ep - bp;
                                p->bp = bp;
                                return (n);
                        }
                }

                nh = (struct nit_hdr *)bp;
                cp = bp + sizeof(*nh);

                switch (nh->nh_state) {

                case NIT_CATCH:
                        break;

                case NIT_NOMBUF:
                case NIT_NOCLUSTER:
                case NIT_NOSPACE:
                        p->md.stat.ps_drop = nh->nh_dropped;
                        continue;

                case NIT_SEQNO:
                        continue;

                default:
                        snprintf(p->errbuf, sizeof(p->errbuf),
                            "bad nit state %d", nh->nh_state);
                        return (-1);
                }
                ++p->md.stat.ps_recv;
                bp += ((sizeof(struct nit_hdr) + nh->nh_datalen +
                    sizeof(int) - 1) & ~(sizeof(int) - 1));

                caplen = nh->nh_wirelen;
                if (caplen > p->snapshot)
                        caplen = p->snapshot;
                if (bpf_filter(p->fcode.bf_insns, cp, nh->nh_wirelen, caplen)) {
                        struct pcap_pkthdr h;
                        h.ts = nh->nh_timestamp;
                        h.len = nh->nh_wirelen;
                        h.caplen = caplen;
                        (*callback)(user, &h, cp);
                        if (++n >= cnt && cnt > 0) {
                                p->cc = ep - bp;
                                p->bp = bp;
                                return (n);
                        }
                }
        }
        p->cc = 0;
        return (n);
}

static int
pcap_inject_nit(pcap_t *p, const void *buf, size_t size)
{
        struct sockaddr sa;
        int ret;

        memset(&sa, 0, sizeof(sa));
        strncpy(sa.sa_data, device, sizeof(sa.sa_data));
        ret = sendto(p->fd, buf, size, 0, &sa, sizeof(sa));
        if (ret == -1) {
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s",
                    pcap_strerror(errno));
                return (-1);
        }
        return (ret);
}                           

static int
nit_setflags(int fd, int promisc, int to_ms, char *ebuf)
{
        struct nit_ioc nioc;

        memset(&nioc, 0, sizeof(nioc));
        nioc.nioc_bufspace = BUFSPACE;
        nioc.nioc_chunksize = CHUNKSIZE;
        nioc.nioc_typetomatch = NT_ALLTYPES;
        nioc.nioc_snaplen = p->snapshot;
        nioc.nioc_bufalign = sizeof(int);
        nioc.nioc_bufoffset = 0;

        if (to_ms != 0) {
                nioc.nioc_flags |= NF_TIMEOUT;
                nioc.nioc_timeout.tv_sec = to_ms / 1000;
                nioc.nioc_timeout.tv_usec = (to_ms * 1000) % 1000000;
        }
        if (promisc)
                nioc.nioc_flags |= NF_PROMISC;

        if (ioctl(fd, SIOCSNIT, &nioc) < 0) {
                snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCSNIT: %s",
                    pcap_strerror(errno));
                return (-1);
        }
        return (0);
}

static void
pcap_close_nit(pcap_t *p)
{
        pcap_close_common(p);
        if (p->device != NULL)
                free(p->device);
}

pcap_t *
pcap_open_live(const char *device, int snaplen, int promisc, int to_ms,
    char *ebuf)
{
        int fd;
        struct sockaddr_nit snit;
        register pcap_t *p;

        p = (pcap_t *)malloc(sizeof(*p));
        if (p == NULL) {
                strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
                return (NULL);
        }

        if (snaplen < 96)
                /*
                 * NIT requires a snapshot length of at least 96.
                 */
                snaplen = 96;

        memset(p, 0, sizeof(*p));
        p->fd = fd = socket(AF_NIT, SOCK_RAW, NITPROTO_RAW);
        if (fd < 0) {
                snprintf(ebuf, PCAP_ERRBUF_SIZE,
                    "socket: %s", pcap_strerror(errno));
                goto bad;
        }
        snit.snit_family = AF_NIT;
        (void)strncpy(snit.snit_ifname, device, NITIFSIZ);

        if (bind(fd, (struct sockaddr *)&snit, sizeof(snit))) {
                snprintf(ebuf, PCAP_ERRBUF_SIZE,
                    "bind: %s: %s", snit.snit_ifname, pcap_strerror(errno));
                goto bad;
        }
        p->snapshot = snaplen;
        nit_setflags(p->fd, promisc, to_ms, ebuf);

        /*
         * NIT supports only ethernets.
         */
        p->linktype = DLT_EN10MB;

        p->bufsize = BUFSPACE;
        p->buffer = (u_char *)malloc(p->bufsize);
        if (p->buffer == NULL) {
                strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
                goto bad;
        }

        /*
         * We need the device name in order to send packets.
         */
        p->device = strdup(device);
        if (p->device == NULL) {
                strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
                free(p->buffer);
                goto bad;
        }

        /*
         * "p->fd" is a socket, so "select()" should work on it.
         */
        p->selectable_fd = p->fd;

        /*
         * This is (presumably) a real Ethernet capture; give it a
         * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
         * that an application can let you choose it, in case you're
         * capturing DOCSIS traffic that a Cisco Cable Modem
         * Termination System is putting out onto an Ethernet (it
         * doesn't put an Ethernet header onto the wire, it puts raw
         * DOCSIS frames out on the wire inside the low-level
         * Ethernet framing).
         */
        p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
        /*
         * If that fails, just leave the list empty.
         */
        if (p->dlt_list != NULL) {
                p->dlt_list[0] = DLT_EN10MB;
                p->dlt_list[1] = DLT_DOCSIS;
                p->dlt_count = 2;
        }

        p->read_op = pcap_read_nit;
        p->inject_op = pcap_inject_nit;
        p->setfilter_op = install_bpf_program;  /* no kernel filtering */
        p->setdirection_op = NULL;      /* Not implemented. */
        p->set_datalink_op = NULL;      /* can't change data link type */
        p->getnonblock_op = pcap_getnonblock_fd;
        p->setnonblock_op = pcap_setnonblock_fd;
        p->stats_op = pcap_stats_nit;
        p->close_op = pcap_close_nit;

        return (p);
 bad:
        if (fd >= 0)
                close(fd);
        free(p);
        return (NULL);
}

int
pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
{
        return (0);
}