int
tcp_parse(const tcp_head_t* tcp, uint32_t sip, uint32_t dip, uint16_t tcpbytes) {
int ret;
// tcp checksum
if (is_local_address(sip)) {
ret = _tcp_checksum(tcp, sip, dip, tcpbytes);
if (ret < 0) { return ret; }
}
// tcp head option
ret = _tcp_head_option(tcp, sip, dip);
if (ret < 0) { return ret; }
// tcpp link
link_key_t key;
link_key_init(&key, sip, dip, ntohs(tcp->sport), ntohs(tcp->dport));
struct link_value_t* val = link_find_insert(&key, is_local_address(sip));
if (!val) return GAZE_TCP_LINK_FAIL;
// tcp flag
ret = _tcp_flag(tcp, &key, val, tcpbytes);
if (ret < 0) { return ret; }
// tcp finish
ret = link_value_is_finish(val);
if (ret == 0) {
link_erase(&key);
}
PRINTF("\n\n");
return GAZE_OK;
}
int
_tcp_head_option(const tcp_head_t* tcp, uint32_t sip, uint32_t dip) {
// tcp port
uint16_t sport, dport;
sport = ntohs(tcp->sport);
dport = ntohs(tcp->dport);
// print address
struct in_addr addr;
addr.s_addr = sip;
if (is_local_address(sip) == 0) {
PRINTF("local[%s:%d] --> peer[", inet_ntoa(addr), sport);
} else {
PRINTF("peer[%s:%d] --> local[", inet_ntoa(addr), sport);
}
addr.s_addr = dip;
PRINTF("%s:%d]\n", inet_ntoa(addr), dport);
// option
int headbytes = (int)(tcp->offx2 >> 4) << 2;
int optbytes = headbytes - sizeof(tcp_head_t);
if (optbytes > 0) {
const unsigned char* start = (const unsigned char*)tcp + sizeof(tcp_head_t);
return _tcp_option(start, optbytes);
}
return 0;
}
int
is_local_address_str(const char *address)
{
char straddress[ADDRESSLEN], *end;
strcpy(straddress, address);
// If address comes with port, remove it
if ((end = strchr(straddress, ':')))
*end = '\0';
return is_local_address(inet_addr(straddress));
}
int
is_local_address_str(const char *address)
{
return is_local_address(inet_addr(address));
}
void
parse_packet(u_char *mode, const struct pcap_pkthdr *header, const u_char *packet)
{
// Datalink Header size
int size_link;
// IP version
uint32_t ip_ver;
// IP header data
struct ip *ip4;
#ifdef WITH_IPV6
// IPv6 header data
struct ip6_hdr *ip6;
#endif
// IP protocol
uint8_t ip_proto;
// IP segment length
uint32_t ip_len;
// IP header size
uint32_t size_ip;
// Fragment offset
uint16_t ip_off = 0;
// Fragmentation flag
uint8_t ip_frag = 0;
// Fragmentation offset
uint16_t ip_frag_off = 0;
//! Source Address
char ip_src[INET6_ADDRSTRLEN + 1];
//! Destination Address
char ip_dst[INET6_ADDRSTRLEN + 1];
// UDP header data
struct udphdr *udp;
// UDP header size
uint16_t udp_size;
// TCP header data
struct tcphdr *tcp;
// TCP header size
uint16_t tcp_size;
// Packet payload data
u_char *msg_payload = NULL;
// Packet payload size
uint32_t size_payload;
// Parsed message data
sip_msg_t *msg;
// Total packet size
uint32_t size_packet;
// SIP message transport
int transport; /* 0 UDP, 1 TCP, 2 TLS */
// Source and Destination Ports
u_short sport, dport;
// 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 link header size from datalink type
size_link = datalink_size(capinfo.link);
// Get IP header
ip4 = (struct ip*) (packet + size_link);
#ifdef WITH_IPV6
// Get IPv6 header
ip6 = (struct ip6_hdr*)(packet + size_link);
#endif
// Get IP version
ip_ver = ip4->ip_v;
switch(ip_ver) {
case 4:
size_ip = ip4->ip_hl * 4;
ip_proto = ip4->ip_p;
ip_len = ntohs(ip4->ip_len);
inet_ntop(AF_INET, &ip4->ip_src, ip_src, sizeof(ip_src));
inet_ntop(AF_INET, &ip4->ip_dst, ip_dst, sizeof(ip_dst));
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;
break;
#ifdef WITH_IPV6
case 6:
size_ip = sizeof(struct ip6_hdr);
ip_proto = ip6->ip6_nxt;
ip_len = ntohs(ip6->ip6_plen);
inet_ntop(AF_INET6, &ip6->ip6_src, ip_src, INET6_ADDRSTRLEN);
inet_ntop(AF_INET6, &ip6->ip6_dst, ip_dst, INET6_ADDRSTRLEN);
if (ip_proto == IPPROTO_FRAGMENT) {
struct ip6_frag *ip6f = (struct ip6_frag *) (ip6 + ip_len);
ip_frag_off = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK);
}
break;
#endif
default:
return;
}
// Only interested in UDP packets
if (ip_proto == IPPROTO_UDP) {
// Set transport UDP
transport = 0;
// Get UDP header
udp = (struct udphdr*) (packet + size_link + size_ip);
udp_size = (ip_frag_off) ? 0 : sizeof(struct udphdr);
// Set packet ports
sport = udp->uh_sport;
dport = udp->uh_dport;
size_payload = htons(udp->uh_ulen) - udp_size;
if ((int32_t)size_payload > 0 ) {
// Get packet payload
msg_payload = malloc(size_payload + 1);
memset(msg_payload, 0, size_payload + 1);
memcpy(msg_payload, (u_char *) (packet + size_link + size_ip + udp_size), size_payload);
}
// Total packet size
size_packet = size_link + size_ip + udp_size + size_payload;
} else if (ip_proto == IPPROTO_TCP) {
// Set transport TCP
transport = 1;
tcp = (struct tcphdr*) (packet + size_link + size_ip);
tcp_size = (ip_frag_off) ? 0 : (tcp->th_off * 4);
// Set packet ports
sport = tcp->th_sport;
dport = tcp->th_dport;
// We're only interested in packets with payload
size_payload = ip_len - (size_ip + tcp_size);
if ((int32_t)size_payload > 0) {
// Get packet payload
msg_payload = malloc(size_payload + 1);
memset(msg_payload, 0, size_payload + 1);
memcpy(msg_payload, (u_char *) (packet + size_link + size_ip + tcp_size), size_payload);
}
// Total packet size
size_packet = size_link + size_ip + tcp_size + size_payload;
#ifdef WITH_OPENSSL
if (!msg_payload || !strstr((const char*) msg_payload, "SIP/2.0")) {
if (capture_get_keyfile()) {
// Allocate memory for the payload
msg_payload = malloc(size_payload + 1);
memset(msg_payload, 0, size_payload + 1);
// Try to decrypt the packet
tls_process_segment(ip4, &msg_payload, &size_payload);
// Check if we have decoded payload
if (size_payload <= 0)
free(msg_payload);
// Set Transport TLS
transport = 2;
}
}
#endif
} else {
// Not handled protocol
return;
}
// Increase capture stats
if (ip4->ip_v == 4 && capinfo.devices) {
if(is_local_address(ip4->ip_src.s_addr)) {
capinfo.local_ports[htons(sport)]++;
capinfo.remote_ports[htons(dport)]++;
} else {
capinfo.remote_ports[htons(sport)]++;
capinfo.local_ports[htons(dport)]++;
}
}
// We're only interested in packets with payload
if (size_payload <= 0)
return;
// Parse this header and payload
msg = sip_load_message(header, ip_src, sport, ip_dst, dport, msg_payload);
free(msg_payload);
// This is not a sip message, Bye!
if (!msg)
return;
// Store Transport attribute
if (transport == 0) {
msg_set_attribute(msg, SIP_ATTR_TRANSPORT, "UDP");
} else if (transport == 1) {
msg_set_attribute(msg, SIP_ATTR_TRANSPORT, "TCP");
} else if (transport == 2) {
msg_set_attribute(msg, SIP_ATTR_TRANSPORT, "TLS");
}
// Set message PCAP data
msg->pcap_packet = malloc(size_packet);
memcpy(msg->pcap_packet, packet, size_packet);
// Store this packets in output file
dump_packet(capinfo.pd, header, packet);
}
int
process_ip(pcap_t *dev, const struct ip *ip, struct timeval tv) {
char src[16], dst[16], *addr;
int incoming;
unsigned len;
addr = inet_ntoa(ip->ip_src);
strncpy(src, addr, 15);
src[15] = '\0';
addr = inet_ntoa(ip->ip_dst);
strncpy(dst, addr, 15);
dst[15] = '\0';
if (is_local_address(ip->ip_src))
incoming = 0;
else if (is_local_address(ip->ip_dst))
incoming = 1;
else
return 1;
len = htons(ip->ip_len);
switch (ip->ip_p) {
struct tcphdr *tcp;
uint16_t sport, dport, lport, rport;
unsigned datalen;
case IPPROTO_TCP:
tcp = (struct tcphdr *) ((unsigned char *) ip + sizeof(struct ip));
#if defined(__FAVOR_BSD)
sport = ntohs(tcp->th_sport);
dport = ntohs(tcp->th_dport);
datalen = len - sizeof(struct ip) - tcp->th_off * 4; // 4 bits offset
#else
sport = ntohs(tcp->source);
dport = ntohs(tcp->dest);
datalen = len - sizeof(struct ip) - tcp->doff * 4;
#endif
// Capture only "data" packets, ignore TCP control
if (datalen == 0)
break;
if (incoming) {
lport = dport;
rport = sport;
inbound(tv, ip->ip_dst, ip->ip_src, lport, rport);
}
else {
lport = sport;
rport = dport;
outbound(tv, ip->ip_src, ip->ip_dst, lport, rport);
}
break;
default:
break;
}
return 0;
}