FreeCalypso > hg > gsm-codec-lib
view pcap/rtp-gsmfr-extr.c @ 36:b5726d659915
libgsmefr: rename sidclass.c to sid_class.c,
in preparation for adding sid_insert.c
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Thu, 24 Nov 2022 02:36:47 +0000 |
parents | 851ca64e38e9 |
children | 10f11a2d4042 |
line wrap: on
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/* * This program reads a pcap file, extracts packets belonging to a * particular RTP stream as identified by a source or destination * IP:port, verifies that an unbroken RTP stream is present, in * GSM FR or EFR codec, and writes the FR/EFR frame stream to our * extended-libgsm format binary file, to be fed to decoding test * programs. */ #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <strings.h> #include <pcap/pcap.h> static pcap_t *pcap; static in_addr_t match_ip_addr; static u_short match_udp_port; static unsigned iphdr_addr_offset, udphdr_port_offset; static unsigned link_hdr_len, ethertype_offset; static FILE *outfile; static int stream_init_flag; static unsigned last_seq, last_tstamp, stream_ssrc; static void check_dl_type() { int dltype; dltype = pcap_datalink(pcap); switch (dltype) { case DLT_EN10MB: link_hdr_len = 14; ethertype_offset = 12; break; case DLT_RAW: link_hdr_len = 0; break; case DLT_LINUX_SLL: link_hdr_len = 16; ethertype_offset = 14; break; default: fprintf(stderr, "error: unsupported data link type %d\n", dltype); exit(1); } } static void rtp_stream_logic(rtp_hdr, pkt_idx) u_char *rtp_hdr; unsigned pkt_idx; { unsigned cur_seq, cur_tstamp, cur_ssrc; cur_seq = (rtp_hdr[2] << 8) | rtp_hdr[3]; cur_tstamp = (rtp_hdr[4] << 24) | (rtp_hdr[5] << 16) | (rtp_hdr[6] << 8) | rtp_hdr[7]; cur_ssrc = (rtp_hdr[8] << 24) | (rtp_hdr[9] << 16) | (rtp_hdr[10] << 8) | rtp_hdr[11]; if (stream_init_flag) { if (cur_ssrc != stream_ssrc) { fprintf(stderr, "error in packet #%u: SSRC change from 0x%08X to 0x%08X\n", pkt_idx, stream_ssrc, cur_ssrc); exit(1); } if (cur_seq != last_seq + 1) { fprintf(stderr, "error in packet #%u: seq break from 0x%04X to 0x%04X\n", pkt_idx, last_seq, cur_seq); exit(1); } if (cur_tstamp != last_tstamp + 160) { fprintf(stderr, "error in packet #%u: timestamp break from 0x%08X to 0x%08X\n", pkt_idx, last_tstamp, cur_tstamp); exit(1); } } else { stream_init_flag = 1; stream_ssrc = cur_ssrc; } last_seq = cur_seq; last_tstamp = cur_tstamp; } static void process_packet(pkt, caplen, pkt_idx) u_char *pkt; unsigned caplen, pkt_idx; { unsigned udplen, payload_len; if (caplen < link_hdr_len + 28) return; if (link_hdr_len) { if (pkt[ethertype_offset] != 0x08) return; if (pkt[ethertype_offset+1] != 0x00) return; pkt += link_hdr_len; caplen -= link_hdr_len; } /* check IP header */ if (pkt[0] != 0x45) return; if (pkt[9] != 17) /* UDP */ return; if (bcmp(pkt + iphdr_addr_offset, &match_ip_addr, 4)) return; /* check UDP header */ if (bcmp(pkt + 20 + udphdr_port_offset, &match_udp_port, 2)) return; /* it is our target - now scrutinize it */ udplen = (pkt[24] << 8) | pkt[25]; if (caplen < udplen + 20) { fprintf(stderr, "error: packet #%u is truncated in the capture\n", pkt_idx); exit(1); } if (udplen < 20) { fprintf(stderr, "error in packet #%u: UDP length is too short for RTP header\n", pkt_idx); exit(1); } if (pkt[28] != 0x80) { fprintf(stderr, "error in packet #%u: unsupported RTP header structure\n", pkt_idx); exit(1); } rtp_stream_logic(pkt + 28, pkt_idx); payload_len = udplen - 20; switch (payload_len) { case 2: if (pkt[40] == 0xBF) break; goto bad_payload; case 31: if ((pkt[40] & 0xF0) == 0xC0) break; goto bad_payload; case 33: if ((pkt[40] & 0xF0) == 0xD0) break; /* FALL THRU */ default: bad_payload: fprintf(stderr, "error in packet #%u: unsupported payload\n", pkt_idx); exit(1); } fwrite(pkt + 40, 1, payload_len, outfile); } main(argc, argv) char **argv; { char errbuf[PCAP_ERRBUF_SIZE]; u_char *pkt; struct pcap_pkthdr pkthdr; unsigned pkt_idx; if (argc != 6) { fprintf(stderr, "usage: %s pcap-file src|dest ip-addr udp-port outfile\n", argv[0]); exit(1); } pcap = pcap_open_offline(argv[1], errbuf); if (!pcap) { fprintf(stderr, "%s: %s\n", argv[1], errbuf); exit(1); } check_dl_type(); if (!strcmp(argv[2], "src")) { iphdr_addr_offset = 12; udphdr_port_offset = 0; } else if (!strcmp(argv[2], "dest")) { iphdr_addr_offset = 16; udphdr_port_offset = 2; } else { fprintf(stderr, "error: direction argument must be \"src\" or \"dest\"\n"); exit(1); } match_ip_addr = inet_addr(argv[3]); if (match_ip_addr == INADDR_NONE) { fprintf(stderr, "error: IP address argument is invalid\n"); exit(1); } match_udp_port = htons(strtoul(argv[4], 0, 0)); outfile = fopen(argv[5], "w"); if (!outfile) { perror(argv[5]); exit(1); } for (pkt_idx = 0; ; pkt_idx++) { pkt = pcap_next(pcap, &pkthdr); if (!pkt) break; process_packet(pkt, (unsigned) pkthdr.caplen, pkt_idx); } if (!stream_init_flag) { fprintf(stderr, "error: specified RTP stream not found\n"); exit(1); } fclose(outfile); exit(0); }