| /* $Id$ */ |
| /* |
| * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com) |
| * Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| */ |
| #include <pjmedia/rtp.h> |
| #include <pjmedia/errno.h> |
| #include <pj/log.h> |
| #include <pj/sock.h> /* pj_htonx, pj_htonx */ |
| #include <pj/assert.h> |
| #include <pj/rand.h> |
| #include <pj/string.h> |
| |
| |
| #define THIS_FILE "rtp.c" |
| |
| #define RTP_VERSION 2 |
| |
| #define RTP_SEQ_MOD (1 << 16) |
| #define MAX_DROPOUT ((pj_int16_t)3000) |
| #define MAX_MISORDER ((pj_int16_t)100) |
| #define MIN_SEQUENTIAL ((pj_int16_t)2) |
| |
| static void pjmedia_rtp_seq_restart(pjmedia_rtp_seq_session *seq_ctrl, |
| pj_uint16_t seq); |
| |
| |
| PJ_DEF(pj_status_t) pjmedia_rtp_session_init( pjmedia_rtp_session *ses, |
| int default_pt, |
| pj_uint32_t sender_ssrc ) |
| { |
| PJ_LOG(5, (THIS_FILE, |
| "pjmedia_rtp_session_init: ses=%p, default_pt=%d, ssrc=0x%x", |
| ses, default_pt, sender_ssrc)); |
| |
| /* Check RTP header packing. */ |
| if (sizeof(struct pjmedia_rtp_hdr) != 12) { |
| pj_assert(!"Wrong RTP header packing!"); |
| return PJMEDIA_RTP_EINPACK; |
| } |
| |
| /* If sender_ssrc is not specified, create from random value. */ |
| if (sender_ssrc == 0 || sender_ssrc == (pj_uint32_t)-1) { |
| sender_ssrc = pj_htonl(pj_rand()); |
| } else { |
| sender_ssrc = pj_htonl(sender_ssrc); |
| } |
| |
| /* Initialize session. */ |
| pj_bzero(ses, sizeof(*ses)); |
| |
| /* Initial sequence number SHOULD be random, according to RFC 3550. */ |
| /* According to RFC 3711, it should be random within 2^15 bit */ |
| ses->out_extseq = pj_rand() & 0x7FFF; |
| ses->peer_ssrc = 0; |
| |
| /* Build default header for outgoing RTP packet. */ |
| ses->out_hdr.v = RTP_VERSION; |
| ses->out_hdr.p = 0; |
| ses->out_hdr.x = 0; |
| ses->out_hdr.cc = 0; |
| ses->out_hdr.m = 0; |
| ses->out_hdr.pt = (pj_uint8_t) default_pt; |
| ses->out_hdr.seq = (pj_uint16_t) pj_htons( (pj_uint16_t)ses->out_extseq ); |
| ses->out_hdr.ts = 0; |
| ses->out_hdr.ssrc = sender_ssrc; |
| |
| /* Keep some arguments as session defaults. */ |
| ses->out_pt = (pj_uint16_t) default_pt; |
| |
| return PJ_SUCCESS; |
| } |
| |
| PJ_DEF(pj_status_t) pjmedia_rtp_session_init2( |
| pjmedia_rtp_session *ses, |
| pjmedia_rtp_session_setting settings) |
| { |
| pj_status_t status; |
| int pt = 0; |
| pj_uint32_t sender_ssrc = 0; |
| |
| if (settings.flags & 1) |
| pt = settings.default_pt; |
| if (settings.flags & 2) |
| sender_ssrc = settings.sender_ssrc; |
| |
| status = pjmedia_rtp_session_init(ses, pt, sender_ssrc); |
| if (status != PJ_SUCCESS) |
| return status; |
| |
| if (settings.flags & 4) { |
| ses->out_extseq = settings.seq; |
| ses->out_hdr.seq = pj_htons((pj_uint16_t)ses->out_extseq); |
| } |
| if (settings.flags & 8) |
| ses->out_hdr.ts = pj_htonl(settings.ts); |
| |
| return PJ_SUCCESS; |
| } |
| |
| |
| PJ_DEF(pj_status_t) pjmedia_rtp_encode_rtp( pjmedia_rtp_session *ses, |
| int pt, int m, |
| int payload_len, int ts_len, |
| const void **rtphdr, int *hdrlen ) |
| { |
| /* Update timestamp */ |
| ses->out_hdr.ts = pj_htonl(pj_ntohl(ses->out_hdr.ts)+ts_len); |
| |
| /* If payload_len is zero, bail out. |
| * This is a clock frame; we're not really transmitting anything. |
| */ |
| if (payload_len == 0) |
| return PJ_SUCCESS; |
| |
| /* Update session. */ |
| ses->out_extseq++; |
| |
| /* Create outgoing header. */ |
| ses->out_hdr.pt = (pj_uint8_t) ((pt == -1) ? ses->out_pt : pt); |
| ses->out_hdr.m = (pj_uint16_t) m; |
| ses->out_hdr.seq = pj_htons( (pj_uint16_t) ses->out_extseq); |
| |
| /* Return values */ |
| *rtphdr = &ses->out_hdr; |
| *hdrlen = sizeof(pjmedia_rtp_hdr); |
| |
| return PJ_SUCCESS; |
| } |
| |
| |
| PJ_DEF(pj_status_t) pjmedia_rtp_decode_rtp( pjmedia_rtp_session *ses, |
| const void *pkt, int pkt_len, |
| const pjmedia_rtp_hdr **hdr, |
| const void **payload, |
| unsigned *payloadlen) |
| { |
| int offset; |
| |
| PJ_UNUSED_ARG(ses); |
| |
| /* Assume RTP header at the start of packet. We'll verify this later. */ |
| *hdr = (pjmedia_rtp_hdr*)pkt; |
| |
| /* Check RTP header sanity. */ |
| if ((*hdr)->v != RTP_VERSION) { |
| return PJMEDIA_RTP_EINVER; |
| } |
| |
| /* Payload is located right after header plus CSRC */ |
| offset = sizeof(pjmedia_rtp_hdr) + ((*hdr)->cc * sizeof(pj_uint32_t)); |
| |
| /* Adjust offset if RTP extension is used. */ |
| if ((*hdr)->x) { |
| pjmedia_rtp_ext_hdr *ext = (pjmedia_rtp_ext_hdr*) |
| (((pj_uint8_t*)pkt) + offset); |
| offset += ((pj_ntohs(ext->length)+1) * sizeof(pj_uint32_t)); |
| } |
| |
| /* Check that offset is less than packet size */ |
| if (offset > pkt_len) |
| return PJMEDIA_RTP_EINLEN; |
| |
| /* Find and set payload. */ |
| *payload = ((pj_uint8_t*)pkt) + offset; |
| *payloadlen = pkt_len - offset; |
| |
| /* Remove payload padding if any */ |
| if ((*hdr)->p && *payloadlen > 0) { |
| pj_uint8_t pad_len; |
| |
| pad_len = ((pj_uint8_t*)(*payload))[*payloadlen - 1]; |
| if (pad_len <= *payloadlen) |
| *payloadlen -= pad_len; |
| } |
| |
| return PJ_SUCCESS; |
| } |
| |
| |
| PJ_DEF(void) pjmedia_rtp_session_update( pjmedia_rtp_session *ses, |
| const pjmedia_rtp_hdr *hdr, |
| pjmedia_rtp_status *p_seq_st) |
| { |
| pjmedia_rtp_session_update2(ses, hdr, p_seq_st, PJ_TRUE); |
| } |
| |
| PJ_DEF(void) pjmedia_rtp_session_update2( pjmedia_rtp_session *ses, |
| const pjmedia_rtp_hdr *hdr, |
| pjmedia_rtp_status *p_seq_st, |
| pj_bool_t check_pt) |
| { |
| pjmedia_rtp_status seq_st; |
| |
| /* for now check_pt MUST be either PJ_TRUE or PJ_FALSE. |
| * In the future we might change check_pt from boolean to |
| * unsigned integer to accommodate more flags. |
| */ |
| pj_assert(check_pt==PJ_TRUE || check_pt==PJ_FALSE); |
| |
| /* Init status */ |
| seq_st.status.value = 0; |
| seq_st.diff = 0; |
| |
| /* Check SSRC. */ |
| if (ses->peer_ssrc == 0) ses->peer_ssrc = pj_ntohl(hdr->ssrc); |
| |
| if (pj_ntohl(hdr->ssrc) != ses->peer_ssrc) { |
| seq_st.status.flag.badssrc = 1; |
| ses->peer_ssrc = pj_ntohl(hdr->ssrc); |
| } |
| |
| /* Check payload type. */ |
| if (check_pt && hdr->pt != ses->out_pt) { |
| if (p_seq_st) { |
| p_seq_st->status.value = seq_st.status.value; |
| p_seq_st->status.flag.bad = 1; |
| p_seq_st->status.flag.badpt = 1; |
| } |
| return; |
| } |
| |
| /* Initialize sequence number on first packet received. */ |
| if (ses->received == 0) |
| pjmedia_rtp_seq_init( &ses->seq_ctrl, pj_ntohs(hdr->seq) ); |
| |
| /* Check sequence number to see if remote session has been restarted. */ |
| pjmedia_rtp_seq_update( &ses->seq_ctrl, pj_ntohs(hdr->seq), &seq_st); |
| if (seq_st.status.flag.restart) { |
| ++ses->received; |
| |
| } else if (!seq_st.status.flag.bad) { |
| ++ses->received; |
| } |
| |
| if (p_seq_st) { |
| p_seq_st->status.value = seq_st.status.value; |
| p_seq_st->diff = seq_st.diff; |
| } |
| } |
| |
| |
| |
| void pjmedia_rtp_seq_restart(pjmedia_rtp_seq_session *sess, pj_uint16_t seq) |
| { |
| sess->base_seq = seq; |
| sess->max_seq = seq; |
| sess->bad_seq = RTP_SEQ_MOD + 1; |
| sess->cycles = 0; |
| } |
| |
| |
| void pjmedia_rtp_seq_init(pjmedia_rtp_seq_session *sess, pj_uint16_t seq) |
| { |
| pjmedia_rtp_seq_restart(sess, seq); |
| |
| sess->max_seq = (pj_uint16_t) (seq - 1); |
| sess->probation = MIN_SEQUENTIAL; |
| } |
| |
| |
| void pjmedia_rtp_seq_update( pjmedia_rtp_seq_session *sess, |
| pj_uint16_t seq, |
| pjmedia_rtp_status *seq_status) |
| { |
| pj_uint16_t udelta = (pj_uint16_t) (seq - sess->max_seq); |
| pjmedia_rtp_status st; |
| |
| /* Init status */ |
| st.status.value = 0; |
| st.diff = 0; |
| |
| /* |
| * Source is not valid until MIN_SEQUENTIAL packets with |
| * sequential sequence numbers have been received. |
| */ |
| if (sess->probation) { |
| |
| st.status.flag.probation = 1; |
| |
| if (seq == sess->max_seq+ 1) { |
| /* packet is in sequence */ |
| st.diff = 1; |
| sess->probation--; |
| sess->max_seq = seq; |
| if (sess->probation == 0) { |
| st.status.flag.probation = 0; |
| } |
| } else { |
| |
| st.diff = 0; |
| |
| st.status.flag.bad = 1; |
| if (seq == sess->max_seq) |
| st.status.flag.dup = 1; |
| else |
| st.status.flag.outorder = 1; |
| |
| sess->probation = MIN_SEQUENTIAL - 1; |
| sess->max_seq = seq; |
| } |
| |
| |
| } else if (udelta == 0) { |
| |
| st.status.flag.dup = 1; |
| |
| } else if (udelta < MAX_DROPOUT) { |
| /* in order, with permissible gap */ |
| if (seq < sess->max_seq) { |
| /* Sequence number wrapped - count another 64K cycle. */ |
| sess->cycles += RTP_SEQ_MOD; |
| } |
| sess->max_seq = seq; |
| |
| st.diff = udelta; |
| |
| } else if (udelta <= (RTP_SEQ_MOD - MAX_MISORDER)) { |
| /* the sequence number made a very large jump */ |
| if (seq == sess->bad_seq) { |
| /* |
| * Two sequential packets -- assume that the other side |
| * restarted without telling us so just re-sync |
| * (i.e., pretend this was the first packet). |
| */ |
| pjmedia_rtp_seq_restart(sess, seq); |
| st.status.flag.restart = 1; |
| st.status.flag.probation = 1; |
| st.diff = 1; |
| } |
| else { |
| sess->bad_seq = (seq + 1) & (RTP_SEQ_MOD-1); |
| st.status.flag.bad = 1; |
| st.status.flag.outorder = 1; |
| } |
| } else { |
| /* old duplicate or reordered packet. |
| * Not necessarily bad packet (?) |
| */ |
| st.status.flag.outorder = 1; |
| } |
| |
| |
| if (seq_status) { |
| seq_status->diff = st.diff; |
| seq_status->status.value = st.status.value; |
| } |
| } |
| |
| |