ref: 79b256df5c397a83037909a9a62a0ebc008d66a4
parent: bbcc1334e0b4d1b58b7ee679b296a8e8eb1bf8fd
author: Ralph Giles <giles@mozilla.com>
date: Mon Aug 27 11:44:49 EDT 2012
Move some of the header parsing logic into functions. The code is a little cleaner now. Also fixes a new warning created by the previous warning fix.
--- a/src/opusrtp.c
+++ b/src/opusrtp.c
@@ -4,11 +4,17 @@
*
*/
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
+#ifdef HAVE_PCAP
#include <pcap.h>
+#endif
#include <ogg/ogg.h>
/* state struct for passing around our handles */
@@ -141,12 +147,12 @@
while (ogg_stream_pageout(params->stream, &page)) {written = fwrite(page.header, 1, page.header_len, params->out);
- if (written != page.header_len) {+ if (written != (size_t)page.header_len) {fprintf(stderr, "Error writing Ogg page header\n");
return -2;
}
written = fwrite(page.body, 1, page.body_len, params->out);
- if (written != page.body_len) {+ if (written != (size_t)page.body_len) {fprintf(stderr, "Error writing Ogg page body\n");
return -3;
}
@@ -167,12 +173,12 @@
while (ogg_stream_flush(params->stream, &page)) {written = fwrite(page.header, 1, page.header_len, params->out);
- if (written != page.header_len) {+ if (written != (size_t)page.header_len) {fprintf(stderr, "Error writing Ogg page header\n");
return -2;
}
written = fwrite(page.body, 1, page.body_len, params->out);
- if (written != page.body_len) {+ if (written != (size_t)page.body_len) {fprintf(stderr, "Error writing Ogg page body\n");
return -3;
}
@@ -181,11 +187,13 @@
return 0;
}
+#define ETH_HEADER_LEN 14
typedef struct {unsigned char src[6], dst[6]; /* ethernet MACs */
int type;
} eth_header;
+#define IP_HEADER_MIN 20
typedef struct {int version;
int header_size;
@@ -193,11 +201,13 @@
int protocol;
} ip_header;
+#define UDP_HEADER_LEN 8
typedef struct {int src, dst; /* ports */
int size, checksum;
} udp_header;
+#define RTP_HEADER_MIN 12
typedef struct {int version;
int type;
@@ -204,15 +214,127 @@
int pad, ext, cc, mark;
int seq, time;
int ssrc;
+ int *csrc;
int header_size;
int payload_size;
} rtp_header;
+/* helper, read a big-endian 16 bit int from memory */
+static int rbe16(const unsigned char *p)
+{+ int v = p[0] << 8 | p[1];
+ return v;
+}
+
+/* helper, read a big-endian 32 bit int from memory */
+static int rbe32(const unsigned char *p)
+{+ int v = p[0] << 24 | p[1] << 16 | p[2] << 8 | p[3];
+ return v;
+}
+
+int parse_eth_header(const unsigned char *packet, int size, eth_header *eth)
+{+ if (!packet || !eth) {+ return -2;
+ }
+ if (size < ETH_HEADER_LEN) {+ fprintf(stderr, "Packet too short for eth\n");
+ return -1;
+ }
+ memcpy(eth->src, packet + 0, 6);
+ memcpy(eth->dst, packet + 6, 6);
+ eth->type = rbe16(packet + 12);
+
+ return 0;
+}
+
+int parse_ip_header(const unsigned char *packet, int size, ip_header *ip)
+{+ if (!packet || !ip) {+ return -2;
+ }
+ if (size < IP_HEADER_MIN) {+ fprintf(stderr, "Packet too short for ip\n");
+ return -1;
+ }
+
+ ip->version = (packet[0] >> 4) & 0x0f;
+ if (ip->version != 4) {+ fprintf(stderr, "unhandled ip version %d\n", ip->version);
+ return 1;
+ }
+
+ /* ipv4 header */
+ ip->header_size = 4 * (packet[0] & 0x0f);
+ ip->protocol = packet[9];
+ memcpy(ip->src, packet + 12, 4);
+ memcpy(ip->dst, packet + 16, 4);
+
+ if (size < ip->header_size) {+ fprintf(stderr, "Packet too short for ipv4 with options\n");
+ return -1;
+ }
+
+ return 0;
+}
+
+int parse_udp_header(const unsigned char *packet, int size, udp_header *udp)
+{+ if (!packet || !udp) {+ return -2;
+ }
+ if (size < UDP_HEADER_LEN) {+ fprintf(stderr, "Packet too short for udp\n");
+ return -1;
+ }
+
+ udp->src = rbe16(packet);
+ udp->dst = rbe16(packet + 2);
+ udp->size = rbe16(packet + 4);
+ udp->checksum = rbe16(packet + 6);
+
+ return 0;
+}
+
+
+int parse_rtp_header(const unsigned char *packet, int size, rtp_header *rtp)
+{+ if (!packet || !rtp) {+ return -2;
+ }
+ if (size < RTP_HEADER_MIN) {+ fprintf(stderr, "Packet too short for rtp\n");
+ return -1;
+ }
+ rtp->version = (packet[0] >> 6) & 3;
+ rtp->pad = (packet[0] >> 5) & 1;
+ rtp->ext = (packet[0] >> 4) & 1;
+ rtp->cc = packet[0] & 7;
+ rtp->header_size = 12 + 4 * rtp->cc;
+ rtp->payload_size = size - rtp->header_size;
+
+ rtp->mark = (packet[1] >> 7) & 1;
+ rtp->type = (packet[1]) & 127;
+ rtp->seq = rbe16(packet + 2);
+ rtp->time = rbe32(packet + 4);
+ rtp->ssrc = rbe32(packet + 8);
+ rtp->csrc = NULL;
+ if (size < rtp->header_size) {+ fprintf(stderr, "Packet too short for RTP header\n");
+ return -1;
+ }
+
+ return 0;
+}
+
/* pcap 'got_packet' callback */
void write_packet(u_char *args, const struct pcap_pkthdr *header,
- const u_char *packet)
+ const u_char *data)
{state *params = (state *)args;
+ const unsigned char *packet;
+ int size;
eth_header eth;
ip_header ip;
udp_header udp;
@@ -220,16 +342,13 @@
fprintf(stderr, "Got %d byte packet (%d bytes captured)\n",
header->len, header->caplen);
+ packet = data;
+ size = header->caplen;
- /* eth header is always 14 bytes */
- if (header->caplen < 14) {- fprintf(stderr, "Packet too short for eth\n");
+ if (parse_eth_header(packet, size, ð)) {+ fprintf(stderr, "error parsing eth header\n");
return;
}
- memcpy(eth.src, packet, 6);
- memcpy(eth.dst, packet + 6, 6);
- eth.type = packet[12] << 8 | packet[13];
-
fprintf(stderr, " eth 0x%04x", eth.type);
fprintf(stderr, " %02x:%02x:%02x:%02x:%02x:%02x ->",
eth.src[0], eth.src[1], eth.src[2],
@@ -237,18 +356,13 @@
fprintf(stderr, " %02x:%02x:%02x:%02x:%02x:%02x\n",
eth.dst[0], eth.dst[1], eth.dst[2],
eth.dst[3], eth.dst[4], eth.dst[5]);
+ packet += ETH_HEADER_LEN;
+ size -= ETH_HEADER_LEN;
- /* ipv4 header */
- if (header->caplen < 14 + 20) {- fprintf(stderr, "Packet too short for ipv4\n");
+ if (parse_ip_header(packet, size, &ip)) {+ fprintf(stderr, "error parsing ip header\n");
return;
}
- ip.version = (packet[14+0] >> 4) & 0x0f;
- ip.header_size = 4 * (packet[14+0] & 0x0f);
- ip.protocol = packet[14 + 9];
- memcpy(ip.src, packet + 14 + 12, 4);
- memcpy(ip.dst, packet + 14 + 16, 4);
-
fprintf(stderr, " ipv%d protocol %d", ip.version, ip.protocol);
fprintf(stderr, " %d.%d.%d.%d ->",
ip.src[0], ip.src[1], ip.src[2], ip.src[3]);
@@ -255,49 +369,22 @@
fprintf(stderr, " %d.%d.%d.%d",
ip.dst[0], ip.dst[1], ip.dst[2], ip.dst[3]);
fprintf(stderr, " header %d bytes\n", ip.header_size);
- if (header->caplen < 14 + ip.header_size) {- fprintf(stderr, "Packet too short for ipv4 with options\n");
- return;
- }
+ packet += ip.header_size;
+ size -= ip.header_size;
- if (header->caplen < 14 + ip.header_size + 8) {- fprintf(stderr, "Packet too short for udp\n");
+ if (parse_udp_header(packet, size, &udp)) {+ fprintf(stderr, "error parsing udp header\n");
return;
}
- udp.src = packet[14+ip.header_size] << 8 |
- packet[14+ip.header_size + 1];
- udp.dst = packet[14+ip.header_size + 2] << 8 |
- packet[14+ip.header_size + 3];
- udp.size = packet[14+ip.header_size + 4] << 8 |
- packet[14+ip.header_size + 5];
- udp.checksum = packet[14+ip.header_size + 6] << 8 |
- packet[14+ip.header_size + 7];
fprintf(stderr, " udp %d bytes %d -> %d crc 0x%04x\n",
udp.size, udp.src, udp.dst, udp.checksum);
- if (header->caplen < 14 + ip.header_size + 8 + 12) {- fprintf(stderr, "Packet too short for rtp\n");
+ packet += UDP_HEADER_LEN;
+ size -= UDP_HEADER_LEN;
+
+ if (parse_rtp_header(packet, size, &rtp)) {+ fprintf(stderr, "error parsing rtp header\n");
return;
}
- rtp.version = (packet[14+ip.header_size+8 + 0] >> 6) & 3;
- rtp.pad = (packet[14+ip.header_size+8] >> 5) & 1;
- rtp.ext = (packet[14+ip.header_size+8] >> 4) & 1;
- rtp.cc = packet[14+ip.header_size+8] & 7;
- rtp.header_size = 12 + 4 * rtp.cc;
- rtp.payload_size = udp.size - 8 - rtp.header_size;
-
- rtp.mark = (packet[14+ip.header_size+8 + 1] >> 7) & 1;
- rtp.type = (packet[14+ip.header_size+8 + 1]) & 127;
- rtp.seq = packet[14+ip.header_size+8 + 2] << 8 |
- packet[14+ip.header_size+8 + 3];
- rtp.time = packet[14+ip.header_size+8 + 4] << 24 |
- packet[14+ip.header_size+8 + 5] << 16 |
- packet[14+ip.header_size+8 + 6] << 8 |
- packet[14+ip.header_size+8 + 7];
- rtp.ssrc = packet[14+ip.header_size+8 + 8] << 24 |
- packet[14+ip.header_size+8 + 9] << 16 |
- packet[14+ip.header_size+8 + 10] << 8 |
- packet[14+ip.header_size+8 + 11];
-
fprintf(stderr, " rtp 0x%08x %d %d %d",
rtp.ssrc, rtp.type, rtp.seq, rtp.time);
fprintf(stderr, " v%d %s%s%s CC %d", rtp.version,
@@ -305,7 +392,10 @@
rtp.mark ? "M":".", rtp.cc);
fprintf(stderr, " %5d bytes\n", rtp.payload_size);
- if (header->caplen < 14 + ip.header_size + 8 + rtp.header_size) {+ packet += rtp.header_size;
+ size -= rtp.header_size;
+
+ if (size < 0) {fprintf(stderr, "skipping short packet\n");
return;
}
@@ -322,10 +412,8 @@
}
/* write the payload to our opus file */
- int size = header->caplen - 14 - ip.header_size - 8 - rtp.header_size;
- unsigned char *data = packet + 14+ip.header_size+8 + rtp.header_size;
- ogg_packet *op = op_from_pkt(data, size);
- op->granulepos = 960*rtp.seq;
+ ogg_packet *op = op_from_pkt(packet, size);
+ op->granulepos = 960*rtp.seq; // FIXME: get this from the toc byte
ogg_stream_packetin(params->stream, op);
free(op);
ogg_write(params);