# HG changeset patch # User Mychaela Falconia # Date 1672103871 0 # Node ID 9bd01faadaedd3c569e238f3c583bd2306bb6f50 # Parent d284f2ac087d680a0cd085f0c13ccd76e200a4dc rtp-g711-extr program written diff -r d284f2ac087d -r 9bd01faadaed .hgignore --- a/.hgignore Tue Dec 27 00:02:28 2022 +0000 +++ b/.hgignore Tue Dec 27 01:17:51 2022 +0000 @@ -41,5 +41,6 @@ ^miscutil/pcm16-wav2raw$ ^pcap/rtp-cont-check$ +^pcap/rtp-g711-extr$ ^pcap/rtp-gsmfr-extr$ ^pcap/rtp-jitter-view$ diff -r d284f2ac087d -r 9bd01faadaed pcap/Makefile --- a/pcap/Makefile Tue Dec 27 00:02:28 2022 +0000 +++ b/pcap/Makefile Tue Dec 27 01:17:51 2022 +0000 @@ -1,6 +1,6 @@ CC= gcc CFLAGS= -O2 -PROGS= rtp-cont-check rtp-gsmfr-extr rtp-jitter-view +PROGS= rtp-cont-check rtp-g711-extr rtp-gsmfr-extr rtp-jitter-view INSTBIN=/opt/freecalypso/bin all: ${PROGS} @@ -8,6 +8,9 @@ rtp-cont-check: rtp-cont-check.c ${CC} ${CFLAGS} -o $@ $@.c -lpcap +rtp-g711-extr: rtp-g711-extr.c + ${CC} ${CFLAGS} -o $@ $@.c -lpcap + rtp-gsmfr-extr: rtp-gsmfr-extr.c ${CC} ${CFLAGS} -o $@ $@.c -lpcap diff -r d284f2ac087d -r 9bd01faadaed pcap/rtp-g711-extr.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/pcap/rtp-g711-extr.c Tue Dec 27 01:17:51 2022 +0000 @@ -0,0 +1,205 @@ +/* + * This program reads a pcap file, extracts packets belonging to a + * particular RTP stream as identified by a source or destination + * IP:port, and verifies that an unbroken RTP stream is present, + * with 160-byte payloads corresponding to timestamp increments + * of 160 units per packet, as expected for a G.711 (PCMU or PCMA) + * RTP stream with 20 ms packetization. The extracted G.711 stream + * is written to a raw binary file. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +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; + if (payload_len != 160) { + 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); +}