1 /* Imported from the dvbstream-0.2 project
2 *
3 * Modified for use with MPlayer, for details see the changelog at
4 * http://svn.mplayerhq.hu/mplayer/trunk/
5 * $Id: rtp.c 29305 2009-05-13 02:58:57Z diego $
6 */
7
8 #include <stdlib.h>
9 #include <string.h>
10 #include <unistd.h>
11 #include <stdlib.h>
12 #include <stdio.h>
13 #include <sys/types.h>
14 #include <ctype.h>
15 #include "config.h"
16 #if !HAVE_WINSOCK2_H
17 #include <netinet/in.h>
18 #include <sys/socket.h>
19 #include <arpa/inet.h>
20 #else
21 #include <winsock2.h>
22 #include <ws2tcpip.h>
23 #endif
24 #include <errno.h>
25 #include "network.h"
26 #include "stream.h"
27
28 /* MPEG-2 TS RTP stack */
29
30 #define DEBUG 1
31 #include "mp_msg.h"
32 #include "rtp.h"
33
34 // RTP reorder routines
35 // Also handling of repeated UDP packets (a bug of ExtremeNetworks switches firmware)
36 // rtpreord procedures
37 // write rtp packets in cache
38 // get rtp packets reordered
39
40 #define MAXRTPPACKETSIN 32 // The number of max packets being reordered
41
42 struct rtpbits {
43 unsigned int v:2; /* version: 2 */
44 unsigned int p:1; /* is there padding appended: 0 */
45 unsigned int x:1; /* number of extension headers: 0 */
46 unsigned int cc:4; /* number of CSRC identifiers: 0 */
47 unsigned int m:1; /* marker: 0 */
48 unsigned int pt:7; /* payload type: 33 for MPEG2 TS - RFC 1890 */
49 unsigned int sequence:16; /* sequence number: random */
50 };
51
52 struct rtpheader { /* in network byte order */
53 struct rtpbits b;
54 int timestamp; /* start: random */
55 int ssrc; /* random */
56 };
57
58 struct rtpbuffer
59 {
60 unsigned char data[MAXRTPPACKETSIN][STREAM_BUFFER_SIZE];
61 unsigned short seq[MAXRTPPACKETSIN];
62 unsigned short len[MAXRTPPACKETSIN];
63 unsigned short first;
64 };
65 static struct rtpbuffer rtpbuf;
66
67 static int getrtp2(int fd, struct rtpheader *rh, char** data, int* lengthData);
68
69 // RTP Reordering functions
70 // Algorithm works as follows:
71 // If next packet is in sequence just copy it to buffer
72 // Otherwise copy it in cache according to its sequence number
73 // Cache is a circular array where "rtpbuf.first" points to next sequence slot
74 // and keeps track of expected sequence
75
76 // Initialize rtp cache
rtp_cache_reset(unsigned short seq)77 static void rtp_cache_reset(unsigned short seq)
78 {
79 int i;
80
81 rtpbuf.first = 0;
82 rtpbuf.seq[0] = ++seq;
83
84 for (i=0; i<MAXRTPPACKETSIN; i++) {
85 rtpbuf.len[i] = 0;
86 }
87 }
88
89 // Write in a cache the rtp packet in right rtp sequence order
rtp_cache(int fd,char * buffer,int length)90 static int rtp_cache(int fd, char *buffer, int length)
91 {
92 struct rtpheader rh;
93 int newseq;
94 char *data;
95 unsigned short seq;
96 static int is_first = 1;
97
98 getrtp2(fd, &rh, &data, &length);
99 if(!length)
100 return 0;
101 seq = rh.b.sequence;
102
103 newseq = seq - rtpbuf.seq[rtpbuf.first];
104
105 if ((newseq == 0) || is_first)
106 {
107 is_first = 0;
108
109 //mp_msg(MSGT_NETWORK, MSGL_DBG4, "RTP (seq[%d]=%d seq=%d, newseq=%d)\n", rtpbuf.first, rtpbuf.seq[rtpbuf.first], seq, newseq);
110 rtpbuf.first = ( 1 + rtpbuf.first ) % MAXRTPPACKETSIN;
111 rtpbuf.seq[rtpbuf.first] = ++seq;
112 goto feed;
113 }
114
115 if (newseq > MAXRTPPACKETSIN)
116 {
117 mp_msg(MSGT_NETWORK, MSGL_DBG2, "Overrun(seq[%d]=%d seq=%d, newseq=%d)\n", rtpbuf.first, rtpbuf.seq[rtpbuf.first], seq, newseq);
118 rtp_cache_reset(seq);
119 goto feed;
120 }
121
122 if (newseq < 0)
123 {
124 int i;
125
126 // Is it a stray packet re-sent to network?
127 for (i=0; i<MAXRTPPACKETSIN; i++) {
128 if (rtpbuf.seq[i] == seq) {
129 mp_msg(MSGT_NETWORK, MSGL_ERR, "Stray packet (seq[%d]=%d seq=%d, newseq=%d found at %d)\n", rtpbuf.first, rtpbuf.seq[rtpbuf.first], seq, newseq, i);
130 return 0; // Yes, it is!
131 }
132 }
133 // Some heuristic to decide when to drop packet or to restart everything
134 if (newseq > -(3 * MAXRTPPACKETSIN)) {
135 mp_msg(MSGT_NETWORK, MSGL_ERR, "Too Old packet (seq[%d]=%d seq=%d, newseq=%d)\n", rtpbuf.first, rtpbuf.seq[rtpbuf.first], seq, newseq);
136 return 0; // Yes, it is!
137 }
138
139 mp_msg(MSGT_NETWORK, MSGL_ERR, "Underrun(seq[%d]=%d seq=%d, newseq=%d)\n", rtpbuf.first, rtpbuf.seq[rtpbuf.first], seq, newseq);
140
141 rtp_cache_reset(seq);
142 goto feed;
143 }
144
145 mp_msg(MSGT_NETWORK, MSGL_DBG4, "Out of Seq (seq[%d]=%d seq=%d, newseq=%d)\n", rtpbuf.first, rtpbuf.seq[rtpbuf.first], seq, newseq);
146 newseq = ( newseq + rtpbuf.first ) % MAXRTPPACKETSIN;
147 memcpy (rtpbuf.data[newseq], data, length);
148 rtpbuf.len[newseq] = length;
149 rtpbuf.seq[newseq] = seq;
150
151 return 0;
152
153 feed:
154 memcpy (buffer, data, length);
155 return length;
156 }
157
158 // Get next packet in cache
159 // Look in cache to get first packet in sequence
rtp_get_next(int fd,char * buffer,int length)160 static int rtp_get_next(int fd, char *buffer, int length)
161 {
162 int i;
163 unsigned short nextseq;
164
165 // If we have empty buffer we loop to fill it
166 for (i=0; i < MAXRTPPACKETSIN -3; i++) {
167 if (rtpbuf.len[rtpbuf.first] != 0) break;
168
169 length = rtp_cache(fd, buffer, length) ;
170
171 // returns on first packet in sequence
172 if (length > 0) {
173 //mp_msg(MSGT_NETWORK, MSGL_DBG4, "Getting rtp [%d] %hu\n", i, rtpbuf.first);
174 return length;
175 } else if (length < 0) break;
176
177 // Only if length == 0 loop continues!
178 }
179
180 i = rtpbuf.first;
181 while (rtpbuf.len[i] == 0) {
182 mp_msg(MSGT_NETWORK, MSGL_ERR, "Lost packet %hu\n", rtpbuf.seq[i]);
183 i = ( 1 + i ) % MAXRTPPACKETSIN;
184 if (rtpbuf.first == i) break;
185 }
186 rtpbuf.first = i;
187
188 // Copy next non empty packet from cache
189 mp_msg(MSGT_NETWORK, MSGL_DBG4, "Getting rtp from cache [%d] %hu\n", rtpbuf.first, rtpbuf.seq[rtpbuf.first]);
190 memcpy (buffer, rtpbuf.data[rtpbuf.first], rtpbuf.len[rtpbuf.first]);
191 length = rtpbuf.len[rtpbuf.first]; // can be zero?
192
193 // Reset fisrt slot and go next in cache
194 rtpbuf.len[rtpbuf.first] = 0;
195 nextseq = rtpbuf.seq[rtpbuf.first];
196 rtpbuf.first = ( 1 + rtpbuf.first ) % MAXRTPPACKETSIN;
197 rtpbuf.seq[rtpbuf.first] = nextseq + 1;
198
199 return length;
200 }
201
202
203 // Read next rtp packet using cache
read_rtp_from_server(int fd,char * buffer,int length)204 int read_rtp_from_server(int fd, char *buffer, int length) {
205 // Following test is ASSERT (i.e. uneuseful if code is correct)
206 if(buffer==NULL || length<STREAM_BUFFER_SIZE) {
207 mp_msg(MSGT_NETWORK, MSGL_ERR, "RTP buffer invalid; no data return from network\n");
208 return 0;
209 }
210
211 // loop just to skip empty packets
212 while ((length = rtp_get_next(fd, buffer, length)) == 0) {
213 mp_msg(MSGT_NETWORK, MSGL_ERR, "Got empty packet from RTP cache!?\n");
214 }
215
216 return length;
217 }
218
getrtp2(int fd,struct rtpheader * rh,char ** data,int * lengthData)219 static int getrtp2(int fd, struct rtpheader *rh, char** data, int* lengthData) {
220 static char buf[1600];
221 unsigned int intP;
222 char* charP = (char*) &intP;
223 int headerSize;
224 int lengthPacket;
225 lengthPacket=recv(fd,buf,1590,0);
226 if (lengthPacket<0)
227 mp_msg(MSGT_NETWORK,MSGL_ERR,"rtp: socket read error\n");
228 else if (lengthPacket<12)
229 mp_msg(MSGT_NETWORK,MSGL_ERR,"rtp: packet too small (%d) to be an rtp frame (>12bytes)\n", lengthPacket);
230 if(lengthPacket<12) {
231 *lengthData = 0;
232 return 0;
233 }
234 rh->b.v = (unsigned int) ((buf[0]>>6)&0x03);
235 rh->b.p = (unsigned int) ((buf[0]>>5)&0x01);
236 rh->b.x = (unsigned int) ((buf[0]>>4)&0x01);
237 rh->b.cc = (unsigned int) ((buf[0]>>0)&0x0f);
238 rh->b.m = (unsigned int) ((buf[1]>>7)&0x01);
239 rh->b.pt = (unsigned int) ((buf[1]>>0)&0x7f);
240 intP = 0;
241 memcpy(charP+2,&buf[2],2);
242 rh->b.sequence = ntohl(intP);
243 intP = 0;
244 memcpy(charP,&buf[4],4);
245 rh->timestamp = ntohl(intP);
246
247 headerSize = 12 + 4*rh->b.cc; /* in bytes */
248
249 *lengthData = lengthPacket - headerSize;
250 *data = (char*) buf + headerSize;
251
252 // mp_msg(MSGT_NETWORK,MSGL_DBG2,"Reading rtp: v=%x p=%x x=%x cc=%x m=%x pt=%x seq=%x ts=%x lgth=%d\n",rh->b.v,rh->b.p,rh->b.x,rh->b.cc,rh->b.m,rh->b.pt,rh->b.sequence,rh->timestamp,lengthPacket);
253
254 return 0;
255 }
256