int
capture_packet_parse(packet_t *packet)
{
// Media structure for RTP packets
rtp_stream_t *stream;
// We're only interested in packets with payload
if (packet_payloadlen(packet)) {
// Parse this header and payload
if (sip_check_packet(packet)) {
return 0;
}
// Check if this packet belongs to a RTP stream
if ((stream = rtp_check_packet(packet))) {
// We have an RTP packet!
packet_set_type(packet, PACKET_RTP);
// Store this pacekt if capture rtp is enabled
if (capture_cfg.rtp_capture) {
call_add_rtp_packet(stream_get_call(stream), packet);
return 0;
}
}
}
return 1;
}
void
parse_packet(u_char *mode, const struct pcap_pkthdr *header, const u_char *packet)
{
// IP header data
struct ip *ip4;
#ifdef WITH_IPV6
// IPv6 header data
struct ip6_hdr *ip6;
#endif
// IP version
uint32_t ip_ver;
// IP protocol
uint8_t ip_proto;
// IP header size
uint32_t ip_hl = 0;
// Fragment offset
uint32_t ip_off = 0;
// Fragmentation flag
uint8_t ip_frag = 0;
// Fragmentation offset
uint16_t ip_frag_off = 0;
//! Source Address
char ip_src[ADDRESSLEN];
//! Destination Address
char ip_dst[ADDRESSLEN];
// Source and Destination Ports
u_short sport, dport;
// UDP header data
struct udphdr *udp;
// UDP header size
uint16_t udp_off;
// TCP header data
struct tcphdr *tcp;
// TCP header size
uint16_t tcp_off;
// Packet payload data
u_char *payload = NULL;
// Packet payload size
uint32_t size_payload = header->caplen;
// SIP message transport
int transport;
// Media structure for RTP packets
rtp_stream_t *stream;
// Captured packet info
capture_packet_t *pkt;
// Ignore packets while capture is paused
if (capture_is_paused())
return;
// Check if we have reached capture limit
if (capinfo.limit && sip_calls_count() >= capinfo.limit)
return;
// Get IP header
ip4 = (struct ip *) (packet + capinfo.link_hl);
#ifdef WITH_IPV6
// Get IPv6 header
ip6 = (struct ip6_hdr *) (packet + capinfo.link_hl);
#endif
// Get IP version
ip_ver = ip4->ip_v;
switch (ip_ver) {
case 4:
ip_hl = ip4->ip_hl * 4;
ip_proto = ip4->ip_p;
ip_off = ntohs(ip4->ip_off);
ip_frag = ip_off & (IP_MF | IP_OFFMASK);
ip_frag_off = (ip_frag) ? (ip_off & IP_OFFMASK) * 8 : 0;
// TODO Get fragment information
inet_ntop(AF_INET, &ip4->ip_src, ip_src, sizeof(ip_src));
inet_ntop(AF_INET, &ip4->ip_dst, ip_dst, sizeof(ip_dst));
break;
#ifdef WITH_IPV6
case 6:
ip_hl = sizeof(struct ip6_hdr);
ip_proto = ip6->ip6_nxt;
if (ip_proto == IPPROTO_FRAGMENT) {
struct ip6_frag *ip6f = (struct ip6_frag *) (ip6 + ip_hl);
ip_frag_off = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK);
// TODO Get fragment information
}
inet_ntop(AF_INET6, &ip6->ip6_src, ip_src, sizeof(ip_src));
inet_ntop(AF_INET6, &ip6->ip6_dst, ip_dst, sizeof(ip_dst));
break;
#endif
default:
return;
}
// Only interested in UDP packets
if (ip_proto == IPPROTO_UDP) {
// Get UDP header
udp = (struct udphdr *)((u_char *)(ip4) + ip_hl);
udp_off = (ip_frag_off) ? 0 : sizeof(struct udphdr);
// Set packet ports
sport = htons(udp->uh_sport);
dport = htons(udp->uh_dport);
// Get actual payload size
size_payload -= capinfo.link_hl + ip_hl + udp_off;
#ifdef WITH_IPV6
if (ip_ver == 6)
size_payload -= ntohs(ip6->ip6_ctlun.ip6_un1.ip6_un1_plen);
#endif
// Get payload start
payload = (u_char *) (udp) + udp_off;
// Set transport UDP
transport = CAPTURE_PACKET_SIP_UDP;
} else if (ip_proto == IPPROTO_TCP) {
// Get TCP header
tcp = (struct tcphdr *)((u_char *)(ip4 )+ ip_hl);
tcp_off = (ip_frag_off) ? 0 : (tcp->th_off * 4);
// Set packet ports
sport = htons(tcp->th_sport);
dport = htons(tcp->th_dport);
// Get actual payload size
size_payload -= capinfo.link_hl + ip_hl + tcp_off;
#ifdef WITH_IPV6
if (ip_ver == 6)
size_payload -= ntohs(ip6->ip6_ctlun.ip6_un1.ip6_un1_plen);
#endif
// Get payload start
payload = (u_char *)(tcp) + tcp_off;
// Set transport TCP
transport = CAPTURE_PACKET_SIP_TCP;
} else {
// Not handled protocol
return;
}
if ((int32_t)size_payload < 0)
size_payload = 0;
// Create a structure for this captured packet
pkt = capture_packet_create(header, packet, header->caplen);
capture_packet_set_type(pkt, transport);
// For TCP and UDP, use payload directly from the packet
capture_packet_set_payload(pkt, NULL, size_payload);
#ifdef WITH_OPENSSL
// Check if packet is TLS
if (capinfo.keyfile && transport == CAPTURE_PACKET_SIP_TCP)
tls_process_segment(ip4, pkt);
#endif
// Check if packet is WS or WSS
if (transport == CAPTURE_PACKET_SIP_TCP)
capture_ws_check_packet(pkt);
// We're only interested in packets with payload
if (capture_packet_get_payload_len(pkt)) {
// Parse this header and payload
if (sip_load_message(pkt, ip_src, sport, ip_dst, dport)) {
// Store this packets in output file
dump_packet(capinfo.pd, header, packet);
return;
}
// Check if this packet belongs to a RTP stream
// TODO Store this packet in the stream
if ((stream = rtp_check_stream(pkt, ip_src, sport, ip_dst, dport))) {
// We have an RTP packet!
capture_packet_set_type(pkt, CAPTURE_PACKET_RTP);
// Store this pacekt if capture rtp is enabled
if (capinfo.rtp_capture) {
call_add_rtp_packet(stream_get_call(stream), pkt);
} else {
capture_packet_destroy(pkt);
}
// Store this packets in output file
dump_packet(capinfo.pd, header, packet);
return;
}
}
// Not an interesting packet ...
capture_packet_destroy(pkt);
}