const char *
hostname_from_question(ns_msg msg) {
static char hostname[256] = {0};
ns_rr rr;
int rrnum, rrmax;
const char *result;
int result_len;
rrmax = ns_msg_count(msg, ns_s_qd);
if (rrmax == 0)
return NULL;
for (rrnum = 0; rrnum < rrmax; rrnum++) {
if (local_ns_parserr(&msg, ns_s_qd, rrnum, &rr)) {
logger_log(LOG_ERR, "local_ns_parserr");
return NULL;
}
result = ns_rr_name(rr);
result_len = strlen(result) + 1;
if (result_len > sizeof(hostname)) {
logger_log(LOG_ERR, "hostname too long: %s", result);
}
memset(hostname, 0, sizeof(hostname));
memcpy(hostname, result, result_len);
return hostname;
}
return NULL;
}
static const char *hostname_from_question(ns_msg msg) {
ns_rr rr;
int rrnum, rrmax;
const char *result;
int result_len;
rrmax = ns_msg_count(msg, ns_s_qd);
if (rrmax == 0)
return NULL;
for (rrnum = 0; rrnum < rrmax; rrnum++) {
if (local_ns_parserr(&msg, ns_s_qd, rrnum, &rr)) {
ERR("local_ns_parserr");
return NULL;
}
result = ns_rr_name(rr);
result_len = strlen(result) + 1;
if (result_len > hostname_buflen) {
hostname_buflen = result_len << 1;
hostname_buf = realloc(hostname_buf, hostname_buflen);
}
memcpy(hostname_buf, result, result_len);
return hostname_buf;
}
return NULL;
}
static int should_filter_query(ns_msg msg, struct in_addr dns_addr) {
ns_rr rr;
int rrnum, rrmax;
void *r;
// TODO cache result for each dns server
int dns_is_chn = 0;
int dns_is_foreign = 0;
if (chnroute_file && (dns_servers_len > 1)) {
dns_is_chn = test_ip_in_list(dns_addr, &chnroute_list);
dns_is_foreign = !dns_is_chn;
}
rrmax = ns_msg_count(msg, ns_s_an);
if (rrmax == 0) {
if (compression) {
// Wait for foreign dns
if (dns_is_chn) {
return 1;
} else {
return 0;
}
}
return -1;
}
for (rrnum = 0; rrnum < rrmax; rrnum++) {
if (local_ns_parserr(&msg, ns_s_an, rrnum, &rr)) {
ERR("local_ns_parserr");
return 0;
}
u_int type;
const u_char *rd;
type = ns_rr_type(rr);
rd = ns_rr_rdata(rr);
if (type == ns_t_a) {
if (verbose)
printf("%s, ", inet_ntoa(*(struct in_addr *)rd));
if (!compression) {
r = bsearch(rd, ip_list.ips, ip_list.entries, sizeof(struct in_addr),
cmp_in_addr);
if (r) {
return 1;
}
}
if (test_ip_in_list(*(struct in_addr *)rd, &chnroute_list)) {
// result is chn
if (dns_is_foreign) {
if (bidirectional) {
// filter DNS result from foreign dns if result is inside chn
return 1;
}
}
} else {
// result is foreign
if (dns_is_chn) {
// filter DNS result from chn dns if result is outside chn
return 1;
}
}
} else if (type == ns_t_aaaa) {
if (dns_is_chn) {
// filter DNS result from chn dns if dns is inside chn
return 1;
}
} else if (type == type == ns_t_ptr) {
// if we've got a PTR result, pass
return 0;
}
}
if (rrmax == 1) {
if (compression) {
return 0;
} else {
return -1;
}
}
return 0;
}
