Implemented filtering based on topdomain

This commit is contained in:
Erik Ekman 2008-08-07 16:49:22 +00:00
parent 6531d5e72b
commit fb3fa24edb

View File

@ -153,17 +153,16 @@ send_version_response(int fd, version_ack_t ack, uint32_t payload, int userid, s
} }
static void static void
handle_null_request(int tun_fd, int dns_fd, struct query *q) handle_null_request(int tun_fd, int dns_fd, struct query *q, int domain_len)
{ {
struct in_addr tempip; struct in_addr tempip;
struct ip *hdr; struct ip *hdr;
unsigned long outlen; unsigned long outlen;
char in[64*1024]; char in[512];
char logindata[16]; char logindata[16];
char out[64*1024]; char out[64*1024];
char unpacked[64*1024]; char unpacked[64*1024];
char *tmp[2]; char *tmp[2];
char *domain;
int userid; int userid;
int touser; int touser;
int version; int version;
@ -171,17 +170,11 @@ handle_null_request(int tun_fd, int dns_fd, struct query *q)
int read; int read;
userid = -1; userid = -1;
domain = strstr(q->name, topdomain);
if (!domain) { memcpy(in, q->name, MIN(domain_len, sizeof(in)));
/* Not for us, discard */
return;
}
read = (int) (domain - q->name);
memcpy(in, q->name, MIN(read, sizeof(in)));
if(in[0] == 'V' || in[0] == 'v') { if(in[0] == 'V' || in[0] == 'v') {
read = unpack_data(unpacked, sizeof(unpacked), &(in[1]), read - 1, b32); read = unpack_data(unpacked, sizeof(unpacked), &(in[1]), domain_len - 1, b32);
/* Version greeting, compare and send ack/nak */ /* Version greeting, compare and send ack/nak */
if (read > 4) { if (read > 4) {
/* Received V + 32bits version */ /* Received V + 32bits version */
@ -212,8 +205,9 @@ handle_null_request(int tun_fd, int dns_fd, struct query *q)
} else { } else {
send_version_response(dns_fd, VERSION_NACK, VERSION, 0, q); send_version_response(dns_fd, VERSION_NACK, VERSION, 0, q);
} }
return;
} else if(in[0] == 'L' || in[0] == 'l') { } else if(in[0] == 'L' || in[0] == 'l') {
read = unpack_data(unpacked, sizeof(unpacked), &(in[1]), read - 1, b32); read = unpack_data(unpacked, sizeof(unpacked), &(in[1]), domain_len - 1, b32);
/* Login phase, handle auth */ /* Login phase, handle auth */
userid = unpacked[0]; userid = unpacked[0];
if (userid < 0 || userid >= USERS) { if (userid < 0 || userid >= USERS) {
@ -246,8 +240,9 @@ handle_null_request(int tun_fd, int dns_fd, struct query *q)
write_dns(dns_fd, q, "LNAK", 4); write_dns(dns_fd, q, "LNAK", 4);
} }
} }
return;
} else if(in[0] == 'P' || in[0] == 'p') { } else if(in[0] == 'P' || in[0] == 'p') {
read = unpack_data(unpacked, sizeof(unpacked), &(in[1]), read - 1, b32); read = unpack_data(unpacked, sizeof(unpacked), &(in[1]), domain_len - 1, b32);
/* Ping packet, store userid */ /* Ping packet, store userid */
userid = unpacked[0]; userid = unpacked[0];
if (userid < 0 || userid >= USERS || ip_cmp(userid, q) != 0) { if (userid < 0 || userid >= USERS || ip_cmp(userid, q) != 0) {
@ -266,7 +261,7 @@ handle_null_request(int tun_fd, int dns_fd, struct query *q)
/* Case conservation check */ /* Case conservation check */
/* Reply with received hostname as data */ /* Reply with received hostname as data */
write_dns(dns_fd, q, in, read); write_dns(dns_fd, q, in, domain_len);
return; return;
} else if((in[0] >= '0' && in[0] <= '9') } else if((in[0] >= '0' && in[0] <= '9')
|| (in[0] >= 'a' && in[0] <= 'f') || (in[0] >= 'a' && in[0] <= 'f')
@ -289,7 +284,7 @@ handle_null_request(int tun_fd, int dns_fd, struct query *q)
write_dns(dns_fd, q, "BADIP", 5); write_dns(dns_fd, q, "BADIP", 5);
} else { } else {
/* decode with this users encoding */ /* decode with this users encoding */
read = unpack_data(unpacked, sizeof(unpacked), &(in[1]), read - 1, read = unpack_data(unpacked, sizeof(unpacked), &(in[1]), domain_len - 1,
users[userid].encoder); users[userid].encoder);
users[userid].last_pkt = time(NULL); users[userid].last_pkt = time(NULL);
@ -340,6 +335,9 @@ tunnel_dns(int tun_fd, int dns_fd)
{ {
struct query q; struct query q;
int read; int read;
char *domain;
int domain_len;
int inside_topdomain;
if ((read = read_dns(dns_fd, &q)) <= 0) if ((read = read_dns(dns_fd, &q)) <= 0)
return 0; return 0;
@ -350,14 +348,27 @@ tunnel_dns(int tun_fd, int dns_fd)
printf("RX: client %s, type %d, name %s\n", inet_ntoa(tempin->sin_addr), q.type, q.name); printf("RX: client %s, type %d, name %s\n", inet_ntoa(tempin->sin_addr), q.type, q.name);
} }
switch (q.type) { domain = strstr(q.name, topdomain);
case T_NULL: inside_topdomain = 0;
handle_null_request(tun_fd, dns_fd, &q); if (domain) {
break; domain_len = (int) (domain - q.name);
default: if (domain_len + strlen(topdomain) == strlen(q.name)) {
break; inside_topdomain = 1;
}
}
if (inside_topdomain) {
/* This is a query we can handle */
switch (q.type) {
case T_NULL:
handle_null_request(tun_fd, dns_fd, &q, domain_len);
break;
default:
break;
}
} else {
/* Forward query to other port ? */
} }
return 0; return 0;
} }