FreeCalypso > hg > rtp-debug-utils

comparison pcap-study/rtp-gsmfr-dump.c @ 10:e686bc92c7d8

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revamp for new subdir structure and configure script
author Mychaela Falconia <falcon@freecalypso.org>
date Wed, 15 May 2024 01:44:46 +0000
parents rtp-gsmfr-dump.c@7c85a7a913f7
children 96b37cef5020
comparison
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9:c00510e1ae8b 10:e686bc92c7d8
1 /*
2 * This program is a combination of rtp-gsmfr-extr and gsmrec-dump into
3 * one step: it reads a pcap file, extracts packets belonging to a
4 * particular RTP stream as identified by a source or destination
5 * IP:port, verifies that an unbroken RTP stream is present, which is
6 * expected to be in GSM FR or EFR codec, but instead of writing this
7 * FR/EFR frame stream to a gsmx file, decodes it like gsmrec-dump.
8 *
9 * The advantage of this program over running rtp-gsmfr-extr followed
10 * by gsmrec-dump is that TRAUlike Extension Headers (if present) are
11 * dumped for analysis, rather than discarded.
12 */
13
14 #include <sys/types.h>
15 #include <sys/socket.h>
16 #include <netinet/in.h>
17 #include <arpa/inet.h>
18 #include <stdio.h>
19 #include <stdlib.h>
20 #include <string.h>
21 #include <strings.h>
22 #include <pcap/pcap.h>
23 #include <gsm.h>
24 #include <gsm_efr.h>
25
26 static pcap_t *pcap;
27 static in_addr_t match_ip_addr;
28 static u_short match_udp_port;
29 static unsigned iphdr_addr_offset, udphdr_port_offset;
30 static unsigned link_hdr_len, ethertype_offset;
31 static int stream_init_flag;
32 static unsigned last_seq, last_tstamp, stream_ssrc;
33 static gsm dummy_state;
34
35 static void
36 check_dl_type()
37 {
38 int dltype;
39
40 dltype = pcap_datalink(pcap);
41 switch (dltype) {
42 case DLT_EN10MB:
43 link_hdr_len = 14;
44 ethertype_offset = 12;
45 break;
46 case DLT_RAW:
47 link_hdr_len = 0;
48 break;
49 case DLT_LINUX_SLL:
50 link_hdr_len = 16;
51 ethertype_offset = 14;
52 break;
53 default:
54 fprintf(stderr, "error: unsupported data link type %d\n",
55 dltype);
56 exit(1);
57 }
58 }
59
60 static void
61 rtp_stream_logic(rtp_hdr, pkt_idx)
62 u_char *rtp_hdr;
63 unsigned pkt_idx;
64 {
65 unsigned cur_seq, cur_tstamp, cur_ssrc;
66
67 cur_seq = (rtp_hdr[2] << 8) | rtp_hdr[3];
68 cur_tstamp = (rtp_hdr[4] << 24) | (rtp_hdr[5] << 16) |
69 (rtp_hdr[6] << 8) | rtp_hdr[7];
70 cur_ssrc = (rtp_hdr[8] << 24) | (rtp_hdr[9] << 16) |
71 (rtp_hdr[10] << 8) | rtp_hdr[11];
72 if (stream_init_flag) {
73 if (cur_ssrc != stream_ssrc) {
74 printf(
75 "error in packet #%u: SSRC change from 0x%08X to 0x%08X\n",
76 pkt_idx, stream_ssrc, cur_ssrc);
77 } else if (cur_seq != last_seq + 1 &&
78 (cur_seq != 0 || last_seq != 0xFFFF)) {
79 printf(
80 "error in packet #%u: seq break from 0x%04X to 0x%04X\n",
81 pkt_idx, last_seq, cur_seq);
82 } else if (cur_tstamp != last_tstamp + 160) {
83 printf(
84 "error in packet #%u: timestamp break from 0x%08X to 0x%08X\n",
85 pkt_idx, last_tstamp, cur_tstamp);
86 }
87 } else
88 stream_init_flag = 1;
89 last_seq = cur_seq;
90 last_tstamp = cur_tstamp;
91 stream_ssrc = cur_ssrc;
92 }
93
94 static void
95 process_payload(payload, payload_len)
96 u_char *payload;
97 unsigned payload_len;
98 {
99 gsm_signal params[76];
100 int i, j, n;
101
102 printf("seq 0x%04X ts 0x%08X: ", last_seq, last_tstamp);
103 switch (payload_len) {
104 case 0:
105 printf("zero-length payload\n");
106 return;
107 case 1:
108 if ((payload[0] & 0xF6) != 0xE6)
109 break;
110 printf("TEH 0x%02X\n", payload[0]);
111 return;
112 case 2:
113 if (payload[0] != 0xBF)
114 break;
115 printf("old BFI TAF=%u\n", payload[1] & 1);
116 return;
117 case 31:
118 if ((payload[0] & 0xF0) != 0xC0)
119 break;
120 printf("std EFR SID=%d LPC", EFR_sid_classify(payload));
121 EFR_frame2params(payload, params);
122 print_efr:
123 n = 0;
124 for (i = 0; i < 5; i++)
125 printf(" %d", params[n++]);
126 putchar('\n');
127 for (i = 0; i < 4; i++) {
128 putchar(' ');
129 for (j = 0; j < 13; j++)
130 printf(" %d", params[n++]);
131 putchar('\n');
132 }
133 return;
134 case 32:
135 if ((payload[0] & 0xF4) != 0xE0)
136 break;
137 if ((payload[1] & 0xF0) != 0xC0)
138 break;
139 printf("TEH 0x%02X EFR SID=%d LPC", payload[0],
140 EFR_sid_classify(payload+1));
141 EFR_frame2params(payload+1, params);
142 goto print_efr;
143 case 33:
144 if ((payload[0] & 0xF0) != 0xD0)
145 break;
146 fputs("std FR", stdout);
147 gsm_explode(dummy_state, payload, params);
148 print_fr:
149 n = 0;
150 for (i = 0; i < 8; i++)
151 printf(" %d", params[n++]);
152 putchar('\n');
153 for (i = 0; i < 4; i++) {
154 putchar(' ');
155 for (j = 0; j < 17; j++)
156 printf(" %d", params[n++]);
157 putchar('\n');
158 }
159 return;
160 case 34:
161 if ((payload[0] & 0xF4) != 0xE0)
162 break;
163 if ((payload[1] & 0xF0) != 0xD0)
164 break;
165 printf("TEH 0x%02X FR", payload[0]);
166 gsm_explode(dummy_state, payload+1, params);
167 goto print_fr;
168 }
169 printf("unknown payload format, length=%u\n", payload_len);
170 }
171
172 static void
173 process_packet(pkt, caplen, pkt_idx)
174 u_char *pkt;
175 unsigned caplen, pkt_idx;
176 {
177 unsigned udplen, payload_len;
178
179 if (caplen < link_hdr_len + 28)
180 return;
181 if (link_hdr_len) {
182 if (pkt[ethertype_offset] != 0x08)
183 return;
184 if (pkt[ethertype_offset+1] != 0x00)
185 return;
186 pkt += link_hdr_len;
187 caplen -= link_hdr_len;
188 }
189 /* check IP header */
190 if (pkt[0] != 0x45)
191 return;
192 if (pkt[9] != 17) /* UDP */
193 return;
194 if (bcmp(pkt + iphdr_addr_offset, &match_ip_addr, 4))
195 return;
196 /* check UDP header */
197 if (bcmp(pkt + 20 + udphdr_port_offset, &match_udp_port, 2))
198 return;
199 /* it is our target - now scrutinize it */
200 udplen = (pkt[24] << 8) | pkt[25];
201 if (caplen < udplen + 20) {
202 fprintf(stderr,
203 "error: packet #%u is truncated in the capture\n",
204 pkt_idx);
205 exit(1);
206 }
207 if (udplen < 20) {
208 fprintf(stderr,
209 "error in packet #%u: UDP length is too short for RTP header\n",
210 pkt_idx);
211 exit(1);
212 }
213 if (pkt[28] != 0x80) {
214 fprintf(stderr,
215 "error in packet #%u: unsupported RTP header structure\n",
216 pkt_idx);
217 exit(1);
218 }
219 rtp_stream_logic(pkt + 28, pkt_idx);
220 process_payload(pkt + 40, udplen - 20);
221 }
222
223 main(argc, argv)
224 char **argv;
225 {
226 char errbuf[PCAP_ERRBUF_SIZE];
227 u_char *pkt;
228 struct pcap_pkthdr pkthdr;
229 unsigned pkt_idx;
230
231 if (argc != 5) {
232 fprintf(stderr,
233 "usage: %s pcap-file src|dest ip-addr udp-port\n",
234 argv[0]);
235 exit(1);
236 }
237 pcap = pcap_open_offline(argv[1], errbuf);
238 if (!pcap) {
239 fprintf(stderr, "%s: %s\n", argv[1], errbuf);
240 exit(1);
241 }
242 check_dl_type();
243 if (!strcmp(argv[2], "src")) {
244 iphdr_addr_offset = 12;
245 udphdr_port_offset = 0;
246 } else if (!strcmp(argv[2], "dest")) {
247 iphdr_addr_offset = 16;
248 udphdr_port_offset = 2;
249 } else {
250 fprintf(stderr,
251 "error: direction argument must be \"src\" or \"dest\"\n");
252 exit(1);
253 }
254 match_ip_addr = inet_addr(argv[3]);
255 if (match_ip_addr == INADDR_NONE) {
256 fprintf(stderr, "error: IP address argument is invalid\n");
257 exit(1);
258 }
259 match_udp_port = htons(strtoul(argv[4], 0, 0));
260 dummy_state = gsm_create();
261 if (!dummy_state) {
262 fprintf(stderr, "gsm_create() failed!\n");
263 exit(1);
264 }
265 for (pkt_idx = 0; ; pkt_idx++) {
266 pkt = pcap_next(pcap, &pkthdr);
267 if (!pkt)
268 break;
269 process_packet(pkt, (unsigned) pkthdr.caplen, pkt_idx);
270 }
271 if (!stream_init_flag) {
272 fprintf(stderr, "error: specified RTP stream not found\n");
273 exit(1);
274 }
275 exit(0);
276 }