FreeCalypso > hg > rtp-debug-utils

comparison rtp-gsmfr-extr.c @ 0:05ff0f7ac977

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initial commit: split from gsm-codec-lib
author Mychaela Falconia <falcon@freecalypso.org>
date Sun, 02 Apr 2023 00:28:28 +0000
parents
children 210dfa39f573
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-1:000000000000 0:05ff0f7ac977
1 /*
2 * This program reads a pcap file, extracts packets belonging to a
3 * particular RTP stream as identified by a source or destination
4 * IP:port, verifies that an unbroken RTP stream is present, in
5 * GSM FR or EFR codec, and writes the FR/EFR frame stream to our
6 * extended-libgsm format binary file, to be fed to decoding test
7 * programs.
8 */
9
10 #include <sys/types.h>
11 #include <sys/socket.h>
12 #include <netinet/in.h>
13 #include <arpa/inet.h>
14 #include <stdio.h>
15 #include <stdlib.h>
16 #include <string.h>
17 #include <strings.h>
18 #include <pcap/pcap.h>
19
20 static pcap_t *pcap;
21 static in_addr_t match_ip_addr;
22 static u_short match_udp_port;
23 static unsigned iphdr_addr_offset, udphdr_port_offset;
24 static unsigned link_hdr_len, ethertype_offset;
25 static FILE *outfile;
26 static int stream_init_flag;
27 static unsigned last_seq, last_tstamp, stream_ssrc;
28
29 static void
30 check_dl_type()
31 {
32 int dltype;
33
34 dltype = pcap_datalink(pcap);
35 switch (dltype) {
36 case DLT_EN10MB:
37 link_hdr_len = 14;
38 ethertype_offset = 12;
39 break;
40 case DLT_RAW:
41 link_hdr_len = 0;
42 break;
43 case DLT_LINUX_SLL:
44 link_hdr_len = 16;
45 ethertype_offset = 14;
46 break;
47 default:
48 fprintf(stderr, "error: unsupported data link type %d\n",
49 dltype);
50 exit(1);
51 }
52 }
53
54 static void
55 rtp_stream_logic(rtp_hdr, pkt_idx)
56 u_char *rtp_hdr;
57 unsigned pkt_idx;
58 {
59 unsigned cur_seq, cur_tstamp, cur_ssrc;
60
61 cur_seq = (rtp_hdr[2] << 8) | rtp_hdr[3];
62 cur_tstamp = (rtp_hdr[4] << 24) | (rtp_hdr[5] << 16) |
63 (rtp_hdr[6] << 8) | rtp_hdr[7];
64 cur_ssrc = (rtp_hdr[8] << 24) | (rtp_hdr[9] << 16) |
65 (rtp_hdr[10] << 8) | rtp_hdr[11];
66 if (stream_init_flag) {
67 if (cur_ssrc != stream_ssrc) {
68 fprintf(stderr,
69 "error in packet #%u: SSRC change from 0x%08X to 0x%08X\n",
70 pkt_idx, stream_ssrc, cur_ssrc);
71 exit(1);
72 }
73 if (cur_seq != last_seq + 1 &&
74 (cur_seq != 0 || last_seq != 0xFFFF)) {
75 fprintf(stderr,
76 "error in packet #%u: seq break from 0x%04X to 0x%04X\n",
77 pkt_idx, last_seq, cur_seq);
78 exit(1);
79 }
80 if (cur_tstamp != last_tstamp + 160) {
81 fprintf(stderr,
82 "error in packet #%u: timestamp break from 0x%08X to 0x%08X\n",
83 pkt_idx, last_tstamp, cur_tstamp);
84 exit(1);
85 }
86 } else {
87 stream_init_flag = 1;
88 stream_ssrc = cur_ssrc;
89 }
90 last_seq = cur_seq;
91 last_tstamp = cur_tstamp;
92 }
93
94 static void
95 process_packet(pkt, caplen, pkt_idx)
96 u_char *pkt;
97 unsigned caplen, pkt_idx;
98 {
99 unsigned udplen, payload_len;
100
101 if (caplen < link_hdr_len + 28)
102 return;
103 if (link_hdr_len) {
104 if (pkt[ethertype_offset] != 0x08)
105 return;
106 if (pkt[ethertype_offset+1] != 0x00)
107 return;
108 pkt += link_hdr_len;
109 caplen -= link_hdr_len;
110 }
111 /* check IP header */
112 if (pkt[0] != 0x45)
113 return;
114 if (pkt[9] != 17) /* UDP */
115 return;
116 if (bcmp(pkt + iphdr_addr_offset, &match_ip_addr, 4))
117 return;
118 /* check UDP header */
119 if (bcmp(pkt + 20 + udphdr_port_offset, &match_udp_port, 2))
120 return;
121 /* it is our target - now scrutinize it */
122 udplen = (pkt[24] << 8) | pkt[25];
123 if (caplen < udplen + 20) {
124 fprintf(stderr,
125 "error: packet #%u is truncated in the capture\n",
126 pkt_idx);
127 exit(1);
128 }
129 if (udplen < 20) {
130 fprintf(stderr,
131 "error in packet #%u: UDP length is too short for RTP header\n",
132 pkt_idx);
133 exit(1);
134 }
135 if (pkt[28] != 0x80) {
136 fprintf(stderr,
137 "error in packet #%u: unsupported RTP header structure\n",
138 pkt_idx);
139 exit(1);
140 }
141 rtp_stream_logic(pkt + 28, pkt_idx);
142 payload_len = udplen - 20;
143 switch (payload_len) {
144 case 2:
145 if (pkt[40] == 0xBF)
146 break;
147 goto bad_payload;
148 case 31:
149 if ((pkt[40] & 0xF0) == 0xC0)
150 break;
151 goto bad_payload;
152 case 33:
153 if ((pkt[40] & 0xF0) == 0xD0)
154 break;
155 /* FALL THRU */
156 default:
157 bad_payload:
158 fprintf(stderr, "error in packet #%u: unsupported payload\n",
159 pkt_idx);
160 exit(1);
161 }
162 fwrite(pkt + 40, 1, payload_len, outfile);
163 }
164
165 main(argc, argv)
166 char **argv;
167 {
168 char errbuf[PCAP_ERRBUF_SIZE];
169 u_char *pkt;
170 struct pcap_pkthdr pkthdr;
171 unsigned pkt_idx;
172
173 if (argc != 6) {
174 fprintf(stderr,
175 "usage: %s pcap-file src|dest ip-addr udp-port outfile\n",
176 argv[0]);
177 exit(1);
178 }
179 pcap = pcap_open_offline(argv[1], errbuf);
180 if (!pcap) {
181 fprintf(stderr, "%s: %s\n", argv[1], errbuf);
182 exit(1);
183 }
184 check_dl_type();
185 if (!strcmp(argv[2], "src")) {
186 iphdr_addr_offset = 12;
187 udphdr_port_offset = 0;
188 } else if (!strcmp(argv[2], "dest")) {
189 iphdr_addr_offset = 16;
190 udphdr_port_offset = 2;
191 } else {
192 fprintf(stderr,
193 "error: direction argument must be \"src\" or \"dest\"\n");
194 exit(1);
195 }
196 match_ip_addr = inet_addr(argv[3]);
197 if (match_ip_addr == INADDR_NONE) {
198 fprintf(stderr, "error: IP address argument is invalid\n");
199 exit(1);
200 }
201 match_udp_port = htons(strtoul(argv[4], 0, 0));
202 outfile = fopen(argv[5], "w");
203 if (!outfile) {
204 perror(argv[5]);
205 exit(1);
206 }
207 for (pkt_idx = 0; ; pkt_idx++) {
208 pkt = pcap_next(pcap, &pkthdr);
209 if (!pkt)
210 break;
211 process_packet(pkt, (unsigned) pkthdr.caplen, pkt_idx);
212 }
213 if (!stream_init_flag) {
214 fprintf(stderr, "error: specified RTP stream not found\n");
215 exit(1);
216 }
217 fclose(outfile);
218 exit(0);
219 }