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 #include "rtp_priv.h" 12 13 #include <stdio.h> 14 #include <string.h> 15 16 #include <sys/types.h> 17 #ifdef HAVE_SYS_SOCKET_H 18 # include <sys/socket.h> 19 #endif 20 21 #define PRINT_DEBUG 0 /* set to 1 to print out debugging data */ 22 #define VERBOSE_DEBUG 0 /* set to 1 to print out more data */ 23 24 unsigned int 25 rtp_sendto(rtp_sender_t sender, const void* msg, int len) { 26 int octets_sent; 27 err_status_t stat; 28 int pkt_len = len + RTP_HEADER_LEN; 29 30 /* marshal data */ 31 strncpy(sender->message.body, msg, len); 32 33 /* update header */ 34 sender->message.header.seq = ntohs(sender->message.header.seq) + 1; 35 sender->message.header.seq = htons(sender->message.header.seq); 36 sender->message.header.ts = ntohl(sender->message.header.ts) + 1; 37 sender->message.header.ts = htonl(sender->message.header.ts); 38 39 /* apply srtp */ 40 stat = srtp_protect(sender->srtp_ctx, &sender->message.header, &pkt_len); 41 if (stat) { 42 #if PRINT_DEBUG 43 fprintf(stderr, "error: srtp protection failed with code %d\n", stat); 44 #endif 45 return -1; 46 } 47 #if VERBOSE_DEBUG 48 srtp_print_packet(&sender->message.header, pkt_len); 49 #endif 50 octets_sent = sendto(sender->socket, (void*)&sender->message, 51 pkt_len, 0, (struct sockaddr *)&sender->addr, 52 sizeof (struct sockaddr_in)); 53 54 if (octets_sent != pkt_len) { 55 #if PRINT_DEBUG 56 fprintf(stderr, "error: couldn't send message %s", (char *)msg); 57 perror(""); 58 #endif 59 } 60 61 return octets_sent; 62 } 63 64 unsigned int 65 rtp_recvfrom(rtp_receiver_t receiver, void *msg, int *len) { 66 int octets_recvd; 67 err_status_t stat; 68 69 octets_recvd = recvfrom(receiver->socket, (void *)&receiver->message, 70 *len, 0, (struct sockaddr *) NULL, 0); 71 72 /* verify rtp header */ 73 if (receiver->message.header.version != 2) { 74 *len = 0; 75 return -1; 76 } 77 78 #if PRINT_DEBUG 79 fprintf(stderr, "%d octets received from SSRC %u\n", 80 octets_recvd, receiver->message.header.ssrc); 81 #endif 82 #if VERBOSE_DEBUG 83 srtp_print_packet(&receiver->message.header, octets_recvd); 84 #endif 85 86 /* apply srtp */ 87 stat = srtp_unprotect(receiver->srtp_ctx, 88 &receiver->message.header, &octets_recvd); 89 if (stat) { 90 fprintf(stderr, 91 "error: srtp unprotection failed with code %d%s\n", stat, 92 stat == err_status_replay_fail ? " (replay check failed)" : 93 stat == err_status_auth_fail ? " (auth check failed)" : ""); 94 return -1; 95 } 96 strncpy(msg, receiver->message.body, octets_recvd); 97 98 return octets_recvd; 99 } 100 101 int 102 rtp_sender_init(rtp_sender_t sender, 103 int socket, 104 struct sockaddr_in addr, 105 unsigned int ssrc) { 106 107 /* set header values */ 108 sender->message.header.ssrc = htonl(ssrc); 109 sender->message.header.ts = 0; 110 sender->message.header.seq = (uint16_t) rand(); 111 sender->message.header.m = 0; 112 sender->message.header.pt = 0x1; 113 sender->message.header.version = 2; 114 sender->message.header.p = 0; 115 sender->message.header.x = 0; 116 sender->message.header.cc = 0; 117 118 /* set other stuff */ 119 sender->socket = socket; 120 sender->addr = addr; 121 122 return 0; 123 } 124 125 int 126 rtp_receiver_init(rtp_receiver_t rcvr, 127 int socket, 128 struct sockaddr_in addr, 129 unsigned int ssrc) { 130 131 /* set header values */ 132 rcvr->message.header.ssrc = htonl(ssrc); 133 rcvr->message.header.ts = 0; 134 rcvr->message.header.seq = 0; 135 rcvr->message.header.m = 0; 136 rcvr->message.header.pt = 0x1; 137 rcvr->message.header.version = 2; 138 rcvr->message.header.p = 0; 139 rcvr->message.header.x = 0; 140 rcvr->message.header.cc = 0; 141 142 /* set other stuff */ 143 rcvr->socket = socket; 144 rcvr->addr = addr; 145 146 return 0; 147 } 148 149 int 150 rtp_sender_init_srtp(rtp_sender_t sender, const srtp_policy_t *policy) { 151 return srtp_create(&sender->srtp_ctx, policy); 152 } 153 154 int 155 rtp_receiver_init_srtp(rtp_receiver_t sender, const srtp_policy_t *policy) { 156 return srtp_create(&sender->srtp_ctx, policy); 157 } 158 159 rtp_sender_t 160 rtp_sender_alloc() { 161 return (rtp_sender_t)malloc(sizeof(rtp_sender_ctx_t)); 162 } 163 164 rtp_receiver_t 165 rtp_receiver_alloc() { 166 return (rtp_receiver_t)malloc(sizeof(rtp_receiver_ctx_t)); 167 } 168
