If PMTUDiscovery is not set, do not forward packets via TCP unnecessarily.

[oweals/tinc.git] / src / net_packet.c

diff --git a/src/net_packet.c b/src/net_packet.c
index 544bbde775024a951d85525571406ca6ce0657c6..de6ae550ed24ddeeede7cb7c87a58b36f2d8c27a 100644 (file)
--- a/src/net_packet.c
+++ b/src/net_packet.c
@@ -168,6 +168,18 @@ static void receive_packet(node_t *n, vpn_packet_t *packet)
        route(n, packet);
 }
 
+static bool try_mac(const node_t *n, const vpn_packet_t *inpkt)
+{
+       unsigned char hmac[EVP_MAX_MD_SIZE];
+
+       if(!n->indigest || !n->inmaclength || !n->inkey || inpkt->len < sizeof inpkt->seqno + n->inmaclength)
+               return false;
+
+       HMAC(n->indigest, n->inkey, n->inkeylength, (unsigned char *) &inpkt->seqno, inpkt->len - n->inmaclength, (unsigned char *)hmac, NULL);
+
+       return !memcmp(hmac, (char *) &inpkt->seqno + inpkt->len - n->inmaclength, n->inmaclength);
+}
+
 static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
 {
        vpn_packet_t pkt1, pkt2;
@@ -180,9 +192,15 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
 
        cp();
 
+       if(!n->inkey) {
+               ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Got packet from %s (%s) but he hasn't got our key yet"),
+                                       n->name, n->hostname);
+               return;
+       }
+
        /* Check packet length */
 
-       if(inpkt->len < sizeof(inpkt->seqno) + myself->maclength) {
+       if(inpkt->len < sizeof(inpkt->seqno) + n->inmaclength) {
                ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Got too short packet from %s (%s)"),
                                        n->name, n->hostname);
                return;
@@ -190,12 +208,12 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
 
        /* Check the message authentication code */
 
-       if(myself->digest && myself->maclength) {
-               inpkt->len -= myself->maclength;
-               HMAC(myself->digest, myself->key, myself->keylength,
+       if(n->indigest && n->inmaclength) {
+               inpkt->len -= n->inmaclength;
+               HMAC(n->indigest, n->inkey, n->inkeylength,
                         (unsigned char *) &inpkt->seqno, inpkt->len, (unsigned char *)hmac, NULL);
 
-               if(memcmp(hmac, (char *) &inpkt->seqno + inpkt->len, myself->maclength)) {
+               if(memcmp(hmac, (char *) &inpkt->seqno + inpkt->len, n->inmaclength)) {
                        ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Got unauthenticated packet from %s (%s)"),
                                           n->name, n->hostname);
                        return;
@@ -204,13 +222,13 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
 
        /* Decrypt the packet */
 
-       if(myself->cipher) {
+       if(n->incipher) {
                outpkt = pkt[nextpkt++];
 
-               if(!EVP_DecryptInit_ex(&packet_ctx, NULL, NULL, NULL, NULL)
-                               || !EVP_DecryptUpdate(&packet_ctx, (unsigned char *) &outpkt->seqno, &outlen,
+               if(!EVP_DecryptInit_ex(&n->inctx, NULL, NULL, NULL, NULL)
+                               || !EVP_DecryptUpdate(&n->inctx, (unsigned char *) &outpkt->seqno, &outlen,
                                        (unsigned char *) &inpkt->seqno, inpkt->len)
-                               || !EVP_DecryptFinal_ex(&packet_ctx, (unsigned char *) &outpkt->seqno + outlen, &outpad)) {
+                               || !EVP_DecryptFinal_ex(&n->inctx, (unsigned char *) &outpkt->seqno + outlen, &outpad)) {
                        ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Error decrypting packet from %s (%s): %s"),
                                                n->name, n->hostname, ERR_error_string(ERR_get_error(), NULL));
                        return;
@@ -253,10 +271,10 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
 
        /* Decompress the packet */
 
-       if(myself->compression) {
+       if(n->incompression) {
                outpkt = pkt[nextpkt++];
 
-               if((outpkt->len = uncompress_packet(outpkt->data, inpkt->data, inpkt->len, myself->compression)) < 0) {
+               if((outpkt->len = uncompress_packet(outpkt->data, inpkt->data, inpkt->len, n->incompression)) < 0) {
                        ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while uncompressing packet from %s (%s)"),
                                                 n->name, n->hostname);
                        return;
@@ -315,7 +333,7 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt)
                                   n->name, n->hostname);
 
                if(!n->status.waitingforkey)
-                       send_req_key(n->nexthop->connection, myself, n);
+                       send_req_key(n);
 
                n->status.waitingforkey = true;
 
@@ -324,12 +342,14 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt)
                return;
        }
 
-       if(!n->minmtu && (inpkt->data[12] | inpkt->data[13])) {
+       if(n->options & OPTION_PMTU_DISCOVERY && !n->minmtu && (inpkt->data[12] | inpkt->data[13])) {
                ifdebug(TRAFFIC) logger(LOG_INFO,
                                _("No minimum MTU established yet for %s (%s), forwarding via TCP"),
                                n->name, n->hostname);
 
                send_tcppacket(n->nexthop->connection, origpkt);
+
+               return;
        }
 
        origlen = inpkt->len;
@@ -337,10 +357,10 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt)
 
        /* Compress the packet */
 
-       if(n->compression) {
+       if(n->outcompression) {
                outpkt = pkt[nextpkt++];
 
-               if((outpkt->len = compress_packet(outpkt->data, inpkt->data, inpkt->len, n->compression)) < 0) {
+               if((outpkt->len = compress_packet(outpkt->data, inpkt->data, inpkt->len, n->outcompression)) < 0) {
                        ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while compressing packet to %s (%s)"),
                                   n->name, n->hostname);
                        return;
@@ -356,13 +376,13 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt)
 
        /* Encrypt the packet */
 
-       if(n->cipher) {
+       if(n->outcipher) {
                outpkt = pkt[nextpkt++];
 
-               if(!EVP_EncryptInit_ex(&n->packet_ctx, NULL, NULL, NULL, NULL)
-                               || !EVP_EncryptUpdate(&n->packet_ctx, (unsigned char *) &outpkt->seqno, &outlen,
+               if(!EVP_EncryptInit_ex(&n->outctx, NULL, NULL, NULL, NULL)
+                               || !EVP_EncryptUpdate(&n->outctx, (unsigned char *) &outpkt->seqno, &outlen,
                                        (unsigned char *) &inpkt->seqno, inpkt->len)
-                               || !EVP_EncryptFinal_ex(&n->packet_ctx, (unsigned char *) &outpkt->seqno + outlen, &outpad)) {
+                               || !EVP_EncryptFinal_ex(&n->outctx, (unsigned char *) &outpkt->seqno + outlen, &outpad)) {
                        ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while encrypting packet to %s (%s): %s"),
                                                n->name, n->hostname, ERR_error_string(ERR_get_error(), NULL));
                        goto end;
@@ -374,10 +394,10 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt)
 
        /* Add the message authentication code */
 
-       if(n->digest && n->maclength) {
-               HMAC(n->digest, n->key, n->keylength, (unsigned char *) &inpkt->seqno,
+       if(n->outdigest && n->outmaclength) {
+               HMAC(n->outdigest, n->outkey, n->outkeylength, (unsigned char *) &inpkt->seqno,
                         inpkt->len, (unsigned char *) &inpkt->seqno + inpkt->len, NULL);
-               inpkt->len += n->maclength;
+               inpkt->len += n->outmaclength;
        }
 
        /* Determine which socket we have to use */
@@ -476,6 +496,30 @@ void broadcast_packet(const node_t *from, vpn_packet_t *packet)
        }
 }
 
+static node_t *try_harder(const sockaddr_t *from, const vpn_packet_t *pkt) {
+       avl_node_t *node;
+       edge_t *e;
+       node_t *n = NULL;
+
+       for(node = edge_weight_tree->head; node; node = node->next) {
+               e = node->data;
+
+               if(sockaddrcmp_noport(from, &e->address))
+                       continue;
+
+               if(!n)
+                       n = e->to;
+
+               if(!try_mac(e->to, pkt))
+                       continue;
+
+               n = e->to;
+               break;
+       }
+
+       return n;
+}
+
 void handle_incoming_vpn_data(int sock)
 {
        vpn_packet_t pkt;
@@ -498,11 +542,15 @@ void handle_incoming_vpn_data(int sock)
        n = lookup_node_udp(&from);
 
        if(!n) {
-               hostname = sockaddr2hostname(&from);
-               logger(LOG_WARNING, _("Received UDP packet from unknown source %s"),
-                          hostname);
-               free(hostname);
-               return;
+               n = try_harder(&from, &pkt);
+               if(n)
+                       update_node_udp(n, &from);
+               else {
+                       hostname = sockaddr2hostname(&from);
+                       logger(LOG_WARNING, _("Received UDP packet from unknown source %s"), hostname);
+                       free(hostname);
+                       return;
+               }
        }
 
        receive_udppacket(n, &pkt);