Add UDP STUN filter

This commit is contained in:
Vadim Vetrov
2025-08-11 20:59:06 +03:00
parent d85c723bbe
commit 65e3613a65
3 changed files with 45 additions and 0 deletions

View File

@@ -333,6 +333,7 @@ enum {
OPT_UDP_FAKE_PAYLOAD_LEN,
OPT_UDP_FAKING_STRATEGY,
OPT_UDP_DPORT_FILTER,
OPT_UDP_STUN_FILTER,
OPT_UDP_FILTER_QUIC,
OPT_TLS_ENABLED,
OPT_CLS,
@@ -373,6 +374,7 @@ static struct option long_opt[] = {
{"udp-fake-len", 1, 0, OPT_UDP_FAKE_PAYLOAD_LEN},
{"udp-faking-strategy", 1, 0, OPT_UDP_FAKING_STRATEGY},
{"udp-dport-filter", 1, 0, OPT_UDP_DPORT_FILTER},
{"udp-stun-filter", 0, 0, OPT_UDP_STUN_FILTER},
{"udp-filter-quic", 1, 0, OPT_UDP_FILTER_QUIC},
{"no-dport-filter", 0, 0, OPT_NO_DPORT_FILTER},
{"threads", 1, 0, OPT_THREADS},
@@ -440,6 +442,7 @@ void print_usage(const char *argv0) {
printf("\t--udp-fake-len=<size of upd fake>\n");
printf("\t--udp-faking-strategy={checksum|ttl|none}\n");
printf("\t--udp-dport-filter=<5,6,200-500>\n");
printf("\t--udp-stun-filter\n");
printf("\t--udp-filter-quic={disabled|all|parse}\n");
printf("\t--no-dport-filter\n");
printf("\t--threads=<threads number>\n");
@@ -927,6 +930,9 @@ int yparse_args(struct config_t *config, int argc, char *argv[]) {
}
break;
}
case OPT_UDP_STUN_FILTER:
sect_config->udp_stun_filter = 1;
break;
case OPT_UDP_FILTER_QUIC:
if (strcmp(optarg, "disabled") == 0) {
sect_config->udp_filter_quic = UDP_FILTER_QUIC_DISABLED;
@@ -1099,6 +1105,10 @@ static size_t print_config_section(const struct section_config_t *section, char
break;
}
if (section->udp_stun_filter) {
print_cnf_buf("--udp-stun-filter");
}
if (section->udp_dport_range_len != 0) {
print_cnf_raw("--udp-dport-filter=");

View File

@@ -107,6 +107,7 @@ struct section_config_t {
struct udp_dport_range *udp_dport_range;
int udp_dport_range_len;
int udp_stun_filter;
int udp_filter_quic;
};

View File

@@ -426,6 +426,35 @@ out:
return 0;
}
int is_stun_message(const uint8_t *data, size_t dlen) {
size_t left_len = dlen;
const uint8_t *data_ptr = data;
uint16_t message_type;
uint16_t message_length;
if (left_len < 2 + 2 + 4 + 12) {
return 0;
}
message_type = *(uint16_t *)data_ptr;
data_ptr += 2;
left_len -= 2;
message_length = *(uint16_t *)data_ptr;
data_ptr += 2;
left_len -= 2;
data_ptr += 4;
left_len -= 4;
data_ptr += 12;
left_len -= 12;
message_type = ntohs(message_type);
message_length = ntohs(message_length);
return (left_len == message_length);
}
int detect_udp_filtered(const struct section_config_t *section,
const uint8_t *payload, size_t plen) {
const void *iph;
@@ -544,6 +573,11 @@ match_port:
}
}
if (section->udp_stun_filter && is_stun_message(data, dlen)) {
lgtrace_addp("STUN protocol detected");
goto approve;
}
skip:
return 0;
approve: