Tristan Matthews | 0a329cc | 2013-07-17 13:20:14 -0400 | [diff] [blame] | 1 | /* $Id$ */ |
| 2 | /* |
| 3 | * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com) |
| 4 | * Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; either version 2 of the License, or |
| 9 | * (at your option) any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU General Public License |
| 17 | * along with this program; if not, write to the Free Software |
| 18 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 19 | */ |
| 20 | #include <pjmedia/rtp.h> |
| 21 | #include <pjmedia/errno.h> |
| 22 | #include <pj/log.h> |
| 23 | #include <pj/sock.h> /* pj_htonx, pj_htonx */ |
| 24 | #include <pj/assert.h> |
| 25 | #include <pj/rand.h> |
| 26 | #include <pj/string.h> |
| 27 | |
| 28 | |
| 29 | #define THIS_FILE "rtp.c" |
| 30 | |
| 31 | #define RTP_VERSION 2 |
| 32 | |
| 33 | #define RTP_SEQ_MOD (1 << 16) |
| 34 | #define MAX_DROPOUT ((pj_int16_t)3000) |
| 35 | #define MAX_MISORDER ((pj_int16_t)100) |
| 36 | #define MIN_SEQUENTIAL ((pj_int16_t)2) |
| 37 | |
| 38 | static void pjmedia_rtp_seq_restart(pjmedia_rtp_seq_session *seq_ctrl, |
| 39 | pj_uint16_t seq); |
| 40 | |
| 41 | |
| 42 | PJ_DEF(pj_status_t) pjmedia_rtp_session_init( pjmedia_rtp_session *ses, |
| 43 | int default_pt, |
| 44 | pj_uint32_t sender_ssrc ) |
| 45 | { |
| 46 | PJ_LOG(5, (THIS_FILE, |
| 47 | "pjmedia_rtp_session_init: ses=%p, default_pt=%d, ssrc=0x%x", |
| 48 | ses, default_pt, sender_ssrc)); |
| 49 | |
| 50 | /* Check RTP header packing. */ |
| 51 | if (sizeof(struct pjmedia_rtp_hdr) != 12) { |
| 52 | pj_assert(!"Wrong RTP header packing!"); |
| 53 | return PJMEDIA_RTP_EINPACK; |
| 54 | } |
| 55 | |
| 56 | /* If sender_ssrc is not specified, create from random value. */ |
| 57 | if (sender_ssrc == 0 || sender_ssrc == (pj_uint32_t)-1) { |
| 58 | sender_ssrc = pj_htonl(pj_rand()); |
| 59 | } else { |
| 60 | sender_ssrc = pj_htonl(sender_ssrc); |
| 61 | } |
| 62 | |
| 63 | /* Initialize session. */ |
| 64 | pj_bzero(ses, sizeof(*ses)); |
| 65 | |
| 66 | /* Initial sequence number SHOULD be random, according to RFC 3550. */ |
| 67 | /* According to RFC 3711, it should be random within 2^15 bit */ |
| 68 | ses->out_extseq = pj_rand() & 0x7FFF; |
| 69 | ses->peer_ssrc = 0; |
| 70 | |
| 71 | /* Build default header for outgoing RTP packet. */ |
| 72 | ses->out_hdr.v = RTP_VERSION; |
| 73 | ses->out_hdr.p = 0; |
| 74 | ses->out_hdr.x = 0; |
| 75 | ses->out_hdr.cc = 0; |
| 76 | ses->out_hdr.m = 0; |
| 77 | ses->out_hdr.pt = (pj_uint8_t) default_pt; |
| 78 | ses->out_hdr.seq = (pj_uint16_t) pj_htons( (pj_uint16_t)ses->out_extseq ); |
| 79 | ses->out_hdr.ts = 0; |
| 80 | ses->out_hdr.ssrc = sender_ssrc; |
| 81 | |
| 82 | /* Keep some arguments as session defaults. */ |
| 83 | ses->out_pt = (pj_uint16_t) default_pt; |
| 84 | |
| 85 | return PJ_SUCCESS; |
| 86 | } |
| 87 | |
| 88 | PJ_DEF(pj_status_t) pjmedia_rtp_session_init2( |
| 89 | pjmedia_rtp_session *ses, |
| 90 | pjmedia_rtp_session_setting settings) |
| 91 | { |
| 92 | pj_status_t status; |
| 93 | int pt = 0; |
| 94 | pj_uint32_t sender_ssrc = 0; |
| 95 | |
| 96 | if (settings.flags & 1) |
| 97 | pt = settings.default_pt; |
| 98 | if (settings.flags & 2) |
| 99 | sender_ssrc = settings.sender_ssrc; |
| 100 | |
| 101 | status = pjmedia_rtp_session_init(ses, pt, sender_ssrc); |
| 102 | if (status != PJ_SUCCESS) |
| 103 | return status; |
| 104 | |
| 105 | if (settings.flags & 4) { |
| 106 | ses->out_extseq = settings.seq; |
| 107 | ses->out_hdr.seq = pj_htons((pj_uint16_t)ses->out_extseq); |
| 108 | } |
| 109 | if (settings.flags & 8) |
| 110 | ses->out_hdr.ts = pj_htonl(settings.ts); |
| 111 | |
| 112 | return PJ_SUCCESS; |
| 113 | } |
| 114 | |
| 115 | |
| 116 | PJ_DEF(pj_status_t) pjmedia_rtp_encode_rtp( pjmedia_rtp_session *ses, |
| 117 | int pt, int m, |
| 118 | int payload_len, int ts_len, |
| 119 | const void **rtphdr, int *hdrlen ) |
| 120 | { |
| 121 | /* Update timestamp */ |
| 122 | ses->out_hdr.ts = pj_htonl(pj_ntohl(ses->out_hdr.ts)+ts_len); |
| 123 | |
| 124 | /* If payload_len is zero, bail out. |
| 125 | * This is a clock frame; we're not really transmitting anything. |
| 126 | */ |
| 127 | if (payload_len == 0) |
| 128 | return PJ_SUCCESS; |
| 129 | |
| 130 | /* Update session. */ |
| 131 | ses->out_extseq++; |
| 132 | |
| 133 | /* Create outgoing header. */ |
| 134 | ses->out_hdr.pt = (pj_uint8_t) ((pt == -1) ? ses->out_pt : pt); |
| 135 | ses->out_hdr.m = (pj_uint16_t) m; |
| 136 | ses->out_hdr.seq = pj_htons( (pj_uint16_t) ses->out_extseq); |
| 137 | |
| 138 | /* Return values */ |
| 139 | *rtphdr = &ses->out_hdr; |
| 140 | *hdrlen = sizeof(pjmedia_rtp_hdr); |
| 141 | |
| 142 | return PJ_SUCCESS; |
| 143 | } |
| 144 | |
| 145 | |
| 146 | PJ_DEF(pj_status_t) pjmedia_rtp_decode_rtp( pjmedia_rtp_session *ses, |
| 147 | const void *pkt, int pkt_len, |
| 148 | const pjmedia_rtp_hdr **hdr, |
| 149 | const void **payload, |
| 150 | unsigned *payloadlen) |
| 151 | { |
| 152 | int offset; |
| 153 | |
| 154 | PJ_UNUSED_ARG(ses); |
| 155 | |
| 156 | /* Assume RTP header at the start of packet. We'll verify this later. */ |
| 157 | *hdr = (pjmedia_rtp_hdr*)pkt; |
| 158 | |
| 159 | /* Check RTP header sanity. */ |
| 160 | if ((*hdr)->v != RTP_VERSION) { |
| 161 | return PJMEDIA_RTP_EINVER; |
| 162 | } |
| 163 | |
| 164 | /* Payload is located right after header plus CSRC */ |
| 165 | offset = sizeof(pjmedia_rtp_hdr) + ((*hdr)->cc * sizeof(pj_uint32_t)); |
| 166 | |
| 167 | /* Adjust offset if RTP extension is used. */ |
| 168 | if ((*hdr)->x) { |
| 169 | pjmedia_rtp_ext_hdr *ext = (pjmedia_rtp_ext_hdr*) |
| 170 | (((pj_uint8_t*)pkt) + offset); |
| 171 | offset += ((pj_ntohs(ext->length)+1) * sizeof(pj_uint32_t)); |
| 172 | } |
| 173 | |
| 174 | /* Check that offset is less than packet size */ |
| 175 | if (offset > pkt_len) |
| 176 | return PJMEDIA_RTP_EINLEN; |
| 177 | |
| 178 | /* Find and set payload. */ |
| 179 | *payload = ((pj_uint8_t*)pkt) + offset; |
| 180 | *payloadlen = pkt_len - offset; |
| 181 | |
| 182 | /* Remove payload padding if any */ |
| 183 | if ((*hdr)->p && *payloadlen > 0) { |
| 184 | pj_uint8_t pad_len; |
| 185 | |
| 186 | pad_len = ((pj_uint8_t*)(*payload))[*payloadlen - 1]; |
| 187 | if (pad_len <= *payloadlen) |
| 188 | *payloadlen -= pad_len; |
| 189 | } |
| 190 | |
| 191 | return PJ_SUCCESS; |
| 192 | } |
| 193 | |
| 194 | |
| 195 | PJ_DEF(void) pjmedia_rtp_session_update( pjmedia_rtp_session *ses, |
| 196 | const pjmedia_rtp_hdr *hdr, |
| 197 | pjmedia_rtp_status *p_seq_st) |
| 198 | { |
| 199 | pjmedia_rtp_session_update2(ses, hdr, p_seq_st, PJ_TRUE); |
| 200 | } |
| 201 | |
| 202 | PJ_DEF(void) pjmedia_rtp_session_update2( pjmedia_rtp_session *ses, |
| 203 | const pjmedia_rtp_hdr *hdr, |
| 204 | pjmedia_rtp_status *p_seq_st, |
| 205 | pj_bool_t check_pt) |
| 206 | { |
| 207 | pjmedia_rtp_status seq_st; |
| 208 | |
| 209 | /* for now check_pt MUST be either PJ_TRUE or PJ_FALSE. |
| 210 | * In the future we might change check_pt from boolean to |
| 211 | * unsigned integer to accommodate more flags. |
| 212 | */ |
| 213 | pj_assert(check_pt==PJ_TRUE || check_pt==PJ_FALSE); |
| 214 | |
| 215 | /* Init status */ |
| 216 | seq_st.status.value = 0; |
| 217 | seq_st.diff = 0; |
| 218 | |
| 219 | /* Check SSRC. */ |
| 220 | if (ses->peer_ssrc == 0) ses->peer_ssrc = pj_ntohl(hdr->ssrc); |
| 221 | |
| 222 | if (pj_ntohl(hdr->ssrc) != ses->peer_ssrc) { |
| 223 | seq_st.status.flag.badssrc = 1; |
| 224 | ses->peer_ssrc = pj_ntohl(hdr->ssrc); |
| 225 | } |
| 226 | |
| 227 | /* Check payload type. */ |
| 228 | if (check_pt && hdr->pt != ses->out_pt) { |
| 229 | if (p_seq_st) { |
| 230 | p_seq_st->status.value = seq_st.status.value; |
| 231 | p_seq_st->status.flag.bad = 1; |
| 232 | p_seq_st->status.flag.badpt = 1; |
| 233 | } |
| 234 | return; |
| 235 | } |
| 236 | |
| 237 | /* Initialize sequence number on first packet received. */ |
| 238 | if (ses->received == 0) |
| 239 | pjmedia_rtp_seq_init( &ses->seq_ctrl, pj_ntohs(hdr->seq) ); |
| 240 | |
| 241 | /* Check sequence number to see if remote session has been restarted. */ |
| 242 | pjmedia_rtp_seq_update( &ses->seq_ctrl, pj_ntohs(hdr->seq), &seq_st); |
| 243 | if (seq_st.status.flag.restart) { |
| 244 | ++ses->received; |
| 245 | |
| 246 | } else if (!seq_st.status.flag.bad) { |
| 247 | ++ses->received; |
| 248 | } |
| 249 | |
| 250 | if (p_seq_st) { |
| 251 | p_seq_st->status.value = seq_st.status.value; |
| 252 | p_seq_st->diff = seq_st.diff; |
| 253 | } |
| 254 | } |
| 255 | |
| 256 | |
| 257 | |
| 258 | void pjmedia_rtp_seq_restart(pjmedia_rtp_seq_session *sess, pj_uint16_t seq) |
| 259 | { |
| 260 | sess->base_seq = seq; |
| 261 | sess->max_seq = seq; |
| 262 | sess->bad_seq = RTP_SEQ_MOD + 1; |
| 263 | sess->cycles = 0; |
| 264 | } |
| 265 | |
| 266 | |
| 267 | void pjmedia_rtp_seq_init(pjmedia_rtp_seq_session *sess, pj_uint16_t seq) |
| 268 | { |
| 269 | pjmedia_rtp_seq_restart(sess, seq); |
| 270 | |
| 271 | sess->max_seq = (pj_uint16_t) (seq - 1); |
| 272 | sess->probation = MIN_SEQUENTIAL; |
| 273 | } |
| 274 | |
| 275 | |
| 276 | void pjmedia_rtp_seq_update( pjmedia_rtp_seq_session *sess, |
| 277 | pj_uint16_t seq, |
| 278 | pjmedia_rtp_status *seq_status) |
| 279 | { |
| 280 | pj_uint16_t udelta = (pj_uint16_t) (seq - sess->max_seq); |
| 281 | pjmedia_rtp_status st; |
| 282 | |
| 283 | /* Init status */ |
| 284 | st.status.value = 0; |
| 285 | st.diff = 0; |
| 286 | |
| 287 | /* |
| 288 | * Source is not valid until MIN_SEQUENTIAL packets with |
| 289 | * sequential sequence numbers have been received. |
| 290 | */ |
| 291 | if (sess->probation) { |
| 292 | |
| 293 | st.status.flag.probation = 1; |
| 294 | |
| 295 | if (seq == sess->max_seq+ 1) { |
| 296 | /* packet is in sequence */ |
| 297 | st.diff = 1; |
| 298 | sess->probation--; |
| 299 | sess->max_seq = seq; |
| 300 | if (sess->probation == 0) { |
| 301 | st.status.flag.probation = 0; |
| 302 | } |
| 303 | } else { |
| 304 | |
| 305 | st.diff = 0; |
| 306 | |
| 307 | st.status.flag.bad = 1; |
| 308 | if (seq == sess->max_seq) |
| 309 | st.status.flag.dup = 1; |
| 310 | else |
| 311 | st.status.flag.outorder = 1; |
| 312 | |
| 313 | sess->probation = MIN_SEQUENTIAL - 1; |
| 314 | sess->max_seq = seq; |
| 315 | } |
| 316 | |
| 317 | |
| 318 | } else if (udelta == 0) { |
| 319 | |
| 320 | st.status.flag.dup = 1; |
| 321 | |
| 322 | } else if (udelta < MAX_DROPOUT) { |
| 323 | /* in order, with permissible gap */ |
| 324 | if (seq < sess->max_seq) { |
| 325 | /* Sequence number wrapped - count another 64K cycle. */ |
| 326 | sess->cycles += RTP_SEQ_MOD; |
| 327 | } |
| 328 | sess->max_seq = seq; |
| 329 | |
| 330 | st.diff = udelta; |
| 331 | |
| 332 | } else if (udelta <= (RTP_SEQ_MOD - MAX_MISORDER)) { |
| 333 | /* the sequence number made a very large jump */ |
| 334 | if (seq == sess->bad_seq) { |
| 335 | /* |
| 336 | * Two sequential packets -- assume that the other side |
| 337 | * restarted without telling us so just re-sync |
| 338 | * (i.e., pretend this was the first packet). |
| 339 | */ |
| 340 | pjmedia_rtp_seq_restart(sess, seq); |
| 341 | st.status.flag.restart = 1; |
| 342 | st.status.flag.probation = 1; |
| 343 | st.diff = 1; |
| 344 | } |
| 345 | else { |
| 346 | sess->bad_seq = (seq + 1) & (RTP_SEQ_MOD-1); |
| 347 | st.status.flag.bad = 1; |
| 348 | st.status.flag.outorder = 1; |
| 349 | } |
| 350 | } else { |
| 351 | /* old duplicate or reordered packet. |
| 352 | * Not necessarily bad packet (?) |
| 353 | */ |
| 354 | st.status.flag.outorder = 1; |
| 355 | } |
| 356 | |
| 357 | |
| 358 | if (seq_status) { |
| 359 | seq_status->diff = st.diff; |
| 360 | seq_status->status.value = st.status.value; |
| 361 | } |
| 362 | } |
| 363 | |
| 364 | |