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SIP: rework detection
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@IvanNardi
IvanNardi committed Nov 11, 2024
1 parent ccbbcdf commit 9425655
Showing 1 changed file with 99 additions and 133 deletions.
232 changes: 99 additions & 133 deletions src/lib/protocols/sip.c
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Original file line number Diff line number Diff line change
Expand Up @@ -36,18 +36,107 @@ static void ndpi_int_sip_add_connection(struct ndpi_detection_module_struct *ndp

/* ********************************************************** */

#if !defined(WIN32)
static inline
#elif defined(MINGW_GCC)
__mingw_forceinline static
#else
__forceinline static
#endif
static int search_cmd(struct ndpi_detection_module_struct *ndpi_struct)
{
struct ndpi_packet_struct *packet = &ndpi_struct->packet;
const u_int8_t *packet_payload = packet->payload;
u_int32_t payload_len = packet->payload_packet_len;
const char **cs;
size_t length;
const char *cmds_a[] = { "Ack sip",
"Ack tel",
NULL };
const char *cmds_b[] = { "Bye sip",
NULL};
const char *cmds_c[] = { "Cancel sip",
"Cancel tel",
NULL};
const char *cmds_i[] = { "Invite sip",
"Info sip",
NULL};
const char *cmds_m[] = { "Message sip",
NULL};
const char *cmds_n[] = { "Notify sip",
NULL};
const char *cmds_o[] = { "Options sip",
"Options tel",
NULL};
const char *cmds_p[] = { "Publish sip",
"Prack sip",
NULL};
const char *cmds_r[] = { "Register sip",
"Refer sip",
NULL};
const char *cmds_s[] = { "Subscribe sip",
"SIP/2.0", /* Reply; useful with asymmetric flows */
NULL};

switch(packet_payload[0]) {
case 'a':
case 'A':
cs = cmds_a;
break;
case 'b':
case 'B':
cs = cmds_b;
break;
case 'c':
case 'C':
cs = cmds_c;
break;
case 'i':
case 'I':
cs = cmds_i;
break;
case 'm':
case 'M':
cs = cmds_m;
break;
case 'n':
case 'N':
cs = cmds_n;
break;
case 'o':
case 'O':
cs = cmds_o;
break;
case 'p':
case 'P':
cs = cmds_p;
break;
case 'r':
case 'R':
cs = cmds_r;
break;
case 's':
case 'S':
cs = cmds_s;
break;
default:
return 0;
}

while(*cs) {
length = strlen(*cs);
if(payload_len > length &&
strncasecmp((const char *)packet_payload, *cs, length) == 0) {
NDPI_LOG_DBG(ndpi_struct, "Matching with [%s]\n", *cs);
return 1;
}
cs++;
}
return 0;
}



void ndpi_search_sip(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow) {
struct ndpi_packet_struct *packet = &ndpi_struct->packet;
const u_int8_t *packet_payload = packet->payload;
u_int32_t payload_len = packet->payload_packet_len;

NDPI_LOG_DBG(ndpi_struct, "Searching for SIP\n");

if(flow->packet_counter >= 8) {
NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
return;
Expand Down Expand Up @@ -75,135 +164,12 @@ void ndpi_search_sip(struct ndpi_detection_module_struct *ndpi_struct, struct nd
return;
}

if(payload_len >= 14) {
if((memcmp(packet_payload, "NOTIFY ", 7) == 0 || memcmp(packet_payload, "notify ", 7) == 0)
&& (memcmp(&packet_payload[7], "SIP:", 4) == 0 || memcmp(&packet_payload[7], "sip:", 4) == 0)) {

NDPI_LOG_INFO(ndpi_struct, "found sip NOTIFY\n");
ndpi_int_sip_add_connection(ndpi_struct, flow);
return;
}

if((memcmp(packet_payload, "REGISTER ", 9) == 0 || memcmp(packet_payload, "register ", 9) == 0)
&& (memcmp(&packet_payload[9], "SIP:", 4) == 0 || memcmp(&packet_payload[9], "sip:", 4) == 0)) {

NDPI_LOG_INFO(ndpi_struct, "found sip REGISTER\n");
ndpi_int_sip_add_connection(ndpi_struct, flow);
return;
}

if((memcmp(packet_payload, "INVITE ", 7) == 0 || memcmp(packet_payload, "invite ", 7) == 0)
&& (memcmp(&packet_payload[7], "SIP:", 4) == 0 || memcmp(&packet_payload[7], "sip:", 4) == 0)) {
NDPI_LOG_INFO(ndpi_struct, "found sip INVITE\n");
ndpi_int_sip_add_connection(ndpi_struct, flow);
return;
}

/* seen this in second direction on the third position,
* maybe it could be deleted, if somebody sees it in the first direction,
* please delete this comment.
*/

/*
if(memcmp(packet_payload, "SIP/2.0 200 OK", 14) == 0 || memcmp(packet_payload, "sip/2.0 200 OK", 14) == 0) {
NDPI_LOG_INFO(ndpi_struct, "found sip SIP/2.0 0K\n");
ndpi_int_sip_add_connection(ndpi_struct, flow);
return;
}
*/
if(memcmp(packet_payload, "SIP/2.0 ", 8) == 0 || memcmp(packet_payload, "sip/2.0 ", 8) == 0) {
NDPI_LOG_INFO(ndpi_struct, "found sip SIP/2.0 *\n");
ndpi_int_sip_add_connection(ndpi_struct, flow);
return;
}

if((memcmp(packet_payload, "BYE ", 4) == 0 || memcmp(packet_payload, "bye ", 4) == 0)
&& (memcmp(&packet_payload[4], "SIP:", 4) == 0 || memcmp(&packet_payload[4], "sip:", 4) == 0)) {
NDPI_LOG_INFO(ndpi_struct, "found sip BYE\n");
ndpi_int_sip_add_connection(ndpi_struct, flow);
return;
}

if((memcmp(packet_payload, "ACK ", 4) == 0 || memcmp(packet_payload, "ack ", 4) == 0)
&& ((memcmp(&packet_payload[4], "SIP:", 4) == 0 || memcmp(&packet_payload[4], "sip:", 4) == 0) ||
(memcmp(&packet_payload[4], "TEL:", 4) == 0 || memcmp(&packet_payload[4], "tel:", 4) == 0))) {
NDPI_LOG_INFO(ndpi_struct, "found sip ACK\n");
if(payload_len >= 30) { /* Arbitrary value: SIP packets are quite big */
if(search_cmd(ndpi_struct) == 1) {
NDPI_LOG_INFO(ndpi_struct, "found sip command\n");
ndpi_int_sip_add_connection(ndpi_struct, flow);
return;
}

if((memcmp(packet_payload, "CANCEL ", 7) == 0 || memcmp(packet_payload, "cancel ", 7) == 0)
&& ((memcmp(&packet_payload[7], "SIP:", 4) == 0 || memcmp(&packet_payload[7], "sip:", 4) == 0) ||
(memcmp(&packet_payload[7], "TEL:", 4) == 0 || memcmp(&packet_payload[7], "tel:", 4) == 0))) {
NDPI_LOG_INFO(ndpi_struct, "found sip CANCEL\n");
ndpi_int_sip_add_connection(ndpi_struct, flow);
return;
}

if((memcmp(packet_payload, "PUBLISH ", 8) == 0 || memcmp(packet_payload, "publish ", 8) == 0)
&& (memcmp(&packet_payload[8], "SIP:", 4) == 0 || memcmp(&packet_payload[8], "sip:", 4) == 0)) {
NDPI_LOG_INFO(ndpi_struct, "found sip PUBLISH\n");
ndpi_int_sip_add_connection(ndpi_struct, flow);
return;
}

if((memcmp(packet_payload, "SUBSCRIBE ", 10) == 0 || memcmp(packet_payload, "subscribe ", 10) == 0)
&& (memcmp(&packet_payload[10], "SIP:", 4) == 0 || memcmp(&packet_payload[10], "sip:", 4) == 0)) {
NDPI_LOG_INFO(ndpi_struct, "found sip SUBSCRIBE\n");
ndpi_int_sip_add_connection(ndpi_struct, flow);
return;
}

/* SIP message extension RFC 3248 */
if((memcmp(packet_payload, "MESSAGE ", 8) == 0 || memcmp(packet_payload, "message ", 8) == 0)
&& (memcmp(&packet_payload[8], "SIP:", 4) == 0 || memcmp(&packet_payload[8], "sip:", 4) == 0)) {
NDPI_LOG_INFO(ndpi_struct, "found sip MESSAGE\n");
ndpi_int_sip_add_connection(ndpi_struct, flow);
return;
}

/* Courtesy of Miguel Quesada <[email protected]> */
if((memcmp(packet_payload, "OPTIONS ", 8) == 0
|| memcmp(packet_payload, "options ", 8) == 0)
&& ((memcmp(&packet_payload[8], "SIP:", 4) == 0 || memcmp(&packet_payload[8], "sip:", 4) == 0) ||
(memcmp(&packet_payload[8], "TEL:", 4) == 0 || memcmp(&packet_payload[8], "tel:", 4) == 0))) {
NDPI_LOG_INFO(ndpi_struct, "found sip OPTIONS\n");
ndpi_int_sip_add_connection(ndpi_struct, flow);
return;
}

if((memcmp(packet_payload, "REFER ", 6) == 0 || memcmp(packet_payload, "refer ", 6) == 0)
&& (memcmp(&packet_payload[6], "SIP:", 4) == 0 || memcmp(&packet_payload[6], "sip:", 4) == 0)) {
NDPI_LOG_INFO(ndpi_struct, "found sip REFER\n");
ndpi_int_sip_add_connection(ndpi_struct, flow);
return;
}

if((memcmp(packet_payload, "PRACK ", 6) == 0 || memcmp(packet_payload, "prack ", 6) == 0)
&& (memcmp(&packet_payload[6], "SIP:", 4) == 0 || memcmp(&packet_payload[6], "sip:", 4) == 0)) {
NDPI_LOG_INFO(ndpi_struct, "found sip PRACK\n");
ndpi_int_sip_add_connection(ndpi_struct, flow);
return;
}

if((memcmp(packet_payload, "INFO ", 5) == 0 || memcmp(packet_payload, "info ", 5) == 0)
&& (memcmp(&packet_payload[5], "SIP:", 4) == 0 || memcmp(&packet_payload[5], "sip:", 4) == 0)) {
NDPI_LOG_INFO(ndpi_struct, "found sip INFO\n");
ndpi_int_sip_add_connection(ndpi_struct, flow);
return;
}
}

/* add bitmask for tcp only, some stupid udp programs
* send a very few (< 10 ) packets before invite (mostly a 0x0a0x0d, but just search the first 3 payload_packets here */
if(packet->udp != NULL) {
NDPI_LOG_DBG2(ndpi_struct, "need next packet\n");
return;
}

if(payload_len == 4 && get_u_int32_t(packet_payload, 0) == 0) {
NDPI_LOG_DBG2(ndpi_struct, "maybe sip. need next packet\n");
return;
}
}

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