The Tcpdump Group git mirrors - libpcap/blob - rpcap-protocol.c

   1 /*
   2  * Copyright (c) 2002 - 2005 NetGroup, Politecnico di Torino (Italy)
   3  * Copyright (c) 2005 - 2008 CACE Technologies, Davis (California)
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  * notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  * notice, this list of conditions and the following disclaimer in the
  14  * documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the Politecnico di Torino, CACE Technologies
  16  * nor the names of its contributors may be used to endorse or promote
  17  * products derived from this software without specific prior written
  18  * permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  21  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  23  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  24  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  25  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  26  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  30  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  31  *
  32  */
  33
  34 #ifdef HAVE_CONFIG_H
  35 #include <config.h>
  36 #endif
  37
  38 #include <string.h>             /* for strlen(), ... */
  39 #include <stdlib.h>             /* for malloc(), free(), ... */
  40 #include <stdarg.h>             /* for functions with variable number of arguments */
  41 #include <errno.h>              /* for the errno variable */
  42 #include "sockutils.h"
  43 #include "portability.h"
  44 #include "rpcap-protocol.h"
  45 #include <pcap/pcap.h>
  46
  47 /*
  48  * This file contains functions used both by the rpcap client and the
  49  * rpcap daemon.
  50  */
  51
  52 /*
  53  * This function sends a RPCAP error to our peer.
  54  *
  55  * It has to be called when the main program detects an error.
  56  * It will send to our peer the 'buffer' specified by the user.
  57  * This function *does not* request a RPCAP CLOSE connection. A CLOSE
  58  * command must be sent explicitly by the program, since we do not know
  59  * whether the error can be recovered in some way or if it is a
  60  * non-recoverable one.
  61  *
  62  * \param sock: the socket we are currently using.
  63  *
  64  * \param ver: the protocol version we want to put in the reply.
  65  *
  66  * \param errcode: a integer which tells the other party the type of error
  67  * we had.
  68  *
  69  * \param error: an user-allocated (and '0' terminated) buffer that contains
  70  * the error description that has to be transmitted to our peer. The
  71  * error message cannot be longer than PCAP_ERRBUF_SIZE.
  72  *
  73  * \param errbuf: a pointer to a user-allocated buffer (of size
  74  * PCAP_ERRBUF_SIZE) that will contain the error message (in case there
  75  * is one). It could be network problem.
  76  *
  77  * \return '0' if everything is fine, '-1' if some errors occurred. The
  78  * error message is returned in the 'errbuf' variable.
  79  */
  80 int
  81 rpcap_senderror(SOCKET sock, uint8 ver, unsigned short errcode, const char *error, char *errbuf)
  82 {
  83         char sendbuf[RPCAP_NETBUF_SIZE];        /* temporary buffer in which data to be sent is buffered */
  84         int sendbufidx = 0;                     /* index which keeps the number of bytes currently buffered */
  85         uint16 length;
  86
  87         length = (uint16)strlen(error);
  88
  89         if (length > PCAP_ERRBUF_SIZE)
  90                 length = PCAP_ERRBUF_SIZE;
  91
  92         rpcap_createhdr((struct rpcap_header *) sendbuf, ver, RPCAP_MSG_ERROR, errcode, length);
  93
  94         if (sock_bufferize(NULL, sizeof(struct rpcap_header), NULL, &sendbufidx,
  95                 RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, errbuf, PCAP_ERRBUF_SIZE))
  96                 return -1;
  97
  98         if (sock_bufferize(error, length, sendbuf, &sendbufidx,
  99                 RPCAP_NETBUF_SIZE, SOCKBUF_BUFFERIZE, errbuf, PCAP_ERRBUF_SIZE))
 100                 return -1;
 101
 102         if (sock_send(sock, sendbuf, sendbufidx, errbuf, PCAP_ERRBUF_SIZE) < 0)
 103                 return -1;
 104
 105         return 0;
 106 }
 107
 108 /*
 109  * This function fills in a structure of type rpcap_header.
 110  *
 111  * It is provided just because the creation of an rpcap header is a common
 112  * task. It accepts all the values that appears into an rpcap_header, and
 113  * it puts them in place using the proper hton() calls.
 114  *
 115  * \param header: a pointer to a user-allocated buffer which will contain
 116  * the serialized header, ready to be sent on the network.
 117  *
 118  * \param ver: a value (in the host byte order) which will be placed into the
 119  * header.ver field and that represents the protocol version number of the
 120  * current message.
 121  *
 122  * \param type: a value (in the host byte order) which will be placed into the
 123  * header.type field and that represents the type of the current message.
 124  *
 125  * \param value: a value (in the host byte order) which will be placed into
 126  * the header.value field and that has a message-dependent meaning.
 127  *
 128  * \param length: a value (in the host by order) which will be placed into
 129  * the header.length field, representing the payload length of the message.
 130  *
 131  * \return Nothing. The serialized header is returned into the 'header'
 132  * variable.
 133  */
 134 void
 135 rpcap_createhdr(struct rpcap_header *header, uint8 ver, uint8 type, uint16 value, uint32 length)
 136 {
 137         memset(header, 0, sizeof(struct rpcap_header));
 138
 139         header->ver = ver;
 140         header->type = type;
 141         header->value = htons(value);
 142         header->plen = htonl(length);
 143 }
 144
 145 /*
 146  * Convert a message type to a string containing the type name.
 147  */
 148 static const char *requests[] =
 149 {
 150         NULL,                           /* not a valid message type */
 151         "RPCAP_MSG_ERROR",
 152         "RPCAP_MSG_FINDALLIF_REQ",
 153         "RPCAP_MSG_OPEN_REQ",
 154         "RPCAP_MSG_STARTCAP_REQ",
 155         "RPCAP_MSG_UPDATEFILTER_REQ",
 156         "RPCAP_MSG_CLOSE",
 157         "RPCAP_MSG_PACKET",
 158         "RPCAP_MSG_AUTH_REQ",
 159         "RPCAP_MSG_STATS_REQ",
 160         "RPCAP_MSG_ENDCAP_REQ",
 161         "RPCAP_MSG_SETSAMPLING_REQ",
 162 };
 163 #define NUM_REQ_TYPES   (sizeof requests / sizeof requests[0])
 164
 165 static const char *replies[] =
 166 {
 167         NULL,
 168         NULL,                   /* this would be a reply to RPCAP_MSG_ERROR */
 169         "RPCAP_MSG_FINDALLIF_REPLY",
 170         "RPCAP_MSG_OPEN_REPLY",
 171         "RPCAP_MSG_STARTCAP_REPLY",
 172         "RPCAP_MSG_UPDATEFILTER_REPLY",
 173         NULL,                   /* this would be a reply to RPCAP_MSG_CLOSE */
 174         NULL,                   /* this would be a reply to RPCAP_MSG_PACKET */
 175         "RPCAP_MSG_AUTH_REPLY",
 176         "RPCAP_MSG_STATS_REPLY",
 177         "RPCAP_MSG_ENDCAP_REPLY",
 178         "RPCAP_MSG_SETSAMPLING_REPLY",
 179 };
 180 #define NUM_REPLY_TYPES (sizeof replies / sizeof replies[0])
 181
 182 const char *
 183 rpcap_msg_type_string(uint8 type)
 184 {
 185         if (type & RPCAP_MSG_IS_REPLY) {
 186                 type &= ~RPCAP_MSG_IS_REPLY;
 187                 if (type >= NUM_REPLY_TYPES)
 188                         return NULL;
 189                 return replies[type];
 190         } else {
 191                 if (type >= NUM_REQ_TYPES)
 192                         return NULL;
 193                 return requests[type];
 194         }
 195 }