diff options
| -rw-r--r-- | net/dns.c | 12 |
1 files changed, 11 insertions, 1 deletions
@@ -58,6 +58,7 @@ struct header { static struct net_connection *dns_con; static uint64_t dns_timer_start; +static uint16_t dns_req_id; static int dns_state; static IPaddr_t dns_ip; @@ -70,9 +71,12 @@ static int dns_send(const char *name) unsigned char *p, *s, *fullname, *dotptr; const unsigned char *domain; + /* generate "difficult" to predict transaction id */ + dns_req_id = dns_timer_start + (dns_timer_start >> 16); + /* Prepare DNS packet header */ header = (struct header *)packet; - header->tid = 1; + header->tid = htons(dns_req_id); header->flags = htons(0x100); /* standard query */ header->nqueries = htons(1); /* Just one query */ header->nanswers = 0; @@ -127,6 +131,12 @@ static void dns_recv(struct header *header, unsigned len) pr_debug("%s\n", __func__); + /* Only accept responses with the expected request id */ + if (ntohs(header->tid) != dns_req_id) { + pr_debug("DNS response with incorrect id\n"); + return; + } + /* We sent 1 query. We want to see more that 1 answer. */ if (ntohs(header->nqueries) != 1) return; |