1 /* 2 * rtp.c 3 * 4 * library functions for the real-time transport protocol 5 * 6 * David A. McGrew 7 * Cisco Systems, Inc. 8 */ 9 /* 10 * 11 * Copyright (c) 2001-2006, Cisco Systems, Inc. 12 * All rights reserved. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 18 * Redistributions of source code must retain the above copyright 19 * notice, this list of conditions and the following disclaimer. 20 * 21 * Redistributions in binary form must reproduce the above 22 * copyright notice, this list of conditions and the following 23 * disclaimer in the documentation and/or other materials provided 24 * with the distribution. 25 * 26 * Neither the name of the Cisco Systems, Inc. nor the names of its 27 * contributors may be used to endorse or promote products derived 28 * from this software without specific prior written permission. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 31 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 32 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 33 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 34 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 35 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 36 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 37 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 41 * OF THE POSSIBILITY OF SUCH DAMAGE. 42 * 43 */ 44 45 46 #include "rtp_priv.h" 47 48 #include <stdio.h> 49 #include <string.h> 50 51 #include <sys/types.h> 52 #ifdef HAVE_SYS_SOCKET_H 53 # include <sys/socket.h> 54 #endif 55 56 #define PRINT_DEBUG 0 /* set to 1 to print out debugging data */ 57 #define VERBOSE_DEBUG 0 /* set to 1 to print out more data */ 58 59 int 60 rtp_sendto(rtp_sender_t sender, const void* msg, int len) { 61 int octets_sent; 62 err_status_t stat; 63 int pkt_len = len + RTP_HEADER_LEN; 64 65 /* marshal data */ 66 strncpy(sender->message.body, msg, len); 67 68 /* update header */ 69 sender->message.header.seq = ntohs(sender->message.header.seq) + 1; 70 sender->message.header.seq = htons(sender->message.header.seq); 71 sender->message.header.ts = ntohl(sender->message.header.ts) + 1; 72 sender->message.header.ts = htonl(sender->message.header.ts); 73 74 /* apply srtp */ 75 stat = srtp_protect(sender->srtp_ctx, &sender->message.header, &pkt_len); 76 if (stat) { 77 #if PRINT_DEBUG 78 fprintf(stderr, "error: srtp protection failed with code %d\n", stat); 79 #endif 80 return -1; 81 } 82 #if VERBOSE_DEBUG 83 srtp_print_packet(&sender->message.header, pkt_len); 84 #endif 85 octets_sent = sendto(sender->socket, (void*)&sender->message, 86 pkt_len, 0, (struct sockaddr *)&sender->addr, 87 sizeof (struct sockaddr_in)); 88 89 if (octets_sent != pkt_len) { 90 #if PRINT_DEBUG 91 fprintf(stderr, "error: couldn't send message %s", (char *)msg); 92 perror(""); 93 #endif 94 } 95 96 return octets_sent; 97 } 98 99 int 100 rtp_recvfrom(rtp_receiver_t receiver, void *msg, int *len) { 101 int octets_recvd; 102 err_status_t stat; 103 104 octets_recvd = recvfrom(receiver->socket, (void *)&receiver->message, 105 *len, 0, (struct sockaddr *) NULL, 0); 106 107 if (octets_recvd == -1) { 108 *len = 0; 109 return -1; 110 } 111 112 /* verify rtp header */ 113 if (receiver->message.header.version != 2) { 114 *len = 0; 115 return -1; 116 } 117 118 #if PRINT_DEBUG 119 fprintf(stderr, "%d octets received from SSRC %u\n", 120 octets_recvd, receiver->message.header.ssrc); 121 #endif 122 #if VERBOSE_DEBUG 123 srtp_print_packet(&receiver->message.header, octets_recvd); 124 #endif 125 126 /* apply srtp */ 127 stat = srtp_unprotect(receiver->srtp_ctx, 128 &receiver->message.header, &octets_recvd); 129 if (stat) { 130 fprintf(stderr, 131 "error: srtp unprotection failed with code %d%s\n", stat, 132 stat == err_status_replay_fail ? " (replay check failed)" : 133 stat == err_status_auth_fail ? " (auth check failed)" : ""); 134 return -1; 135 } 136 strncpy(msg, receiver->message.body, octets_recvd); 137 138 return octets_recvd; 139 } 140 141 int 142 rtp_sender_init(rtp_sender_t sender, 143 int sock, 144 struct sockaddr_in addr, 145 unsigned int ssrc) { 146 147 /* set header values */ 148 sender->message.header.ssrc = htonl(ssrc); 149 sender->message.header.ts = 0; 150 sender->message.header.seq = (uint16_t) rand(); 151 sender->message.header.m = 0; 152 sender->message.header.pt = 0x1; 153 sender->message.header.version = 2; 154 sender->message.header.p = 0; 155 sender->message.header.x = 0; 156 sender->message.header.cc = 0; 157 158 /* set other stuff */ 159 sender->socket = sock; 160 sender->addr = addr; 161 162 return 0; 163 } 164 165 int 166 rtp_receiver_init(rtp_receiver_t rcvr, 167 int sock, 168 struct sockaddr_in addr, 169 unsigned int ssrc) { 170 171 /* set header values */ 172 rcvr->message.header.ssrc = htonl(ssrc); 173 rcvr->message.header.ts = 0; 174 rcvr->message.header.seq = 0; 175 rcvr->message.header.m = 0; 176 rcvr->message.header.pt = 0x1; 177 rcvr->message.header.version = 2; 178 rcvr->message.header.p = 0; 179 rcvr->message.header.x = 0; 180 rcvr->message.header.cc = 0; 181 182 /* set other stuff */ 183 rcvr->socket = sock; 184 rcvr->addr = addr; 185 186 return 0; 187 } 188 189 int 190 rtp_sender_init_srtp(rtp_sender_t sender, const srtp_policy_t *policy) { 191 return srtp_create(&sender->srtp_ctx, policy); 192 } 193 194 int 195 rtp_sender_deinit_srtp(rtp_sender_t sender) { 196 return srtp_dealloc(sender->srtp_ctx); 197 } 198 199 int 200 rtp_receiver_init_srtp(rtp_receiver_t sender, const srtp_policy_t *policy) { 201 return srtp_create(&sender->srtp_ctx, policy); 202 } 203 204 int 205 rtp_receiver_deinit_srtp(rtp_receiver_t sender) { 206 return srtp_dealloc(sender->srtp_ctx); 207 } 208 209 rtp_sender_t 210 rtp_sender_alloc(void) { 211 return (rtp_sender_t)malloc(sizeof(rtp_sender_ctx_t)); 212 } 213 214 void 215 rtp_sender_dealloc(rtp_sender_t rtp_ctx) { 216 free(rtp_ctx); 217 } 218 219 rtp_receiver_t 220 rtp_receiver_alloc(void) { 221 return (rtp_receiver_t)malloc(sizeof(rtp_receiver_ctx_t)); 222 } 223 224 void 225 rtp_receiver_dealloc(rtp_receiver_t rtp_ctx) { 226 return free(rtp_ctx); 227 } 228
