X-Git-Url: https://git.librecmc.org/?p=oweals%2Ftinc.git;a=blobdiff_plain;f=src%2Fnet_packet.c;h=31c44771967a2d62f35da6c34eade0f4411cfc9d;hp=c159efb3fc8e7723ec94bc8b7388627aa339ea72;hb=de029ce46056e02908b5390da9b71a6a59133f26;hpb=67df7fb7e1c9eefe4bbc920fdc68b595ef28abd9

diff --git a/src/net_packet.c b/src/net_packet.c
index c159efb..31c4477 100644
--- a/src/net_packet.c
+++ b/src/net_packet.c
@@ -1,7 +1,7 @@
 /*
     net_packet.c -- Handles in- and outgoing VPN packets
     Copyright (C) 1998-2005 Ivo Timmermans,
-                  2000-2006 Guus Sliepen <guus@tinc-vpn.org>
+                  2000-2009 Guus Sliepen <guus@tinc-vpn.org>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -54,7 +54,6 @@
 
 int keylifetime = 0;
 int keyexpires = 0;
-EVP_CIPHER_CTX packet_ctx;
 static char lzo_wrkmem[LZO1X_999_MEM_COMPRESS > LZO1X_1_MEM_COMPRESS ? LZO1X_999_MEM_COMPRESS : LZO1X_1_MEM_COMPRESS];
 
 static void send_udppacket(node_t *, vpn_packet_t *);
@@ -71,6 +70,11 @@ void send_mtu_probe(node_t *n)
 	n->mtuprobes++;
 	n->mtuevent = NULL;
 
+	if(!n->status.reachable) {
+		logger(LOG_DEBUG, _("Trying to send MTU probe to unreachable node %s (%s)"), n->name, n->hostname);
+		return;
+	}
+
 	if(n->mtuprobes >= 10 && !n->minmtu) {
 		ifdebug(TRAFFIC) logger(LOG_INFO, _("No response to MTU probes from %s (%s)"), n->name, n->hostname);
 		return;
@@ -104,15 +108,15 @@ void send_mtu_probe(node_t *n)
 	event_add(n->mtuevent);
 }
 
-void mtu_probe_h(node_t *n, vpn_packet_t *packet) {
+void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
 	ifdebug(TRAFFIC) logger(LOG_INFO, _("Got MTU probe length %d from %s (%s)"), packet->len, n->name, n->hostname);
 
 	if(!packet->data[0]) {
 		packet->data[0] = 1;
 		send_packet(n, packet);
 	} else {
-		if(n->minmtu < packet->len)
-			n->minmtu = packet->len;
+		if(n->minmtu < len)
+			n->minmtu = len;
 	}
 }
 
@@ -168,6 +172,18 @@ 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 +196,15 @@ 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 +212,12 @@ 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 +226,13 @@ 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;
@@ -253,16 +275,20 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
 
 	/* Decompress the packet */
 
-	if(myself->compression) {
+	length_t origlen = inpkt->len;
+
+	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;
 		}
 
 		inpkt = outpkt;
+
+		origlen -= MTU/64 + 20;
 	}
 
 	inpkt->priority = 0;
@@ -271,7 +297,7 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
 		n->connection->last_ping_time = now;
 
 	if(!inpkt->data[12] && !inpkt->data[13])
-		mtu_probe_h(n, inpkt);
+		mtu_probe_h(n, inpkt, origlen);
 	else
 		receive_packet(n, inpkt);
 }
@@ -307,6 +333,11 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt)
 
 	cp();
 
+	if(!n->status.reachable) {
+		ifdebug(TRAFFIC) logger(LOG_INFO, _("Trying to send UDP packet to unreachable node %s (%s)"), n->name, n->hostname);
+		return;
+	}
+
 	/* Make sure we have a valid key */
 
 	if(!n->status.validkey) {
@@ -315,7 +346,7 @@ 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 +355,14 @@ 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 +370,10 @@ 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 +389,13 @@ 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 +407,10 @@ 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 */
@@ -465,9 +498,15 @@ void broadcast_packet(const node_t *from, vpn_packet_t *packet)
 	ifdebug(TRAFFIC) logger(LOG_INFO, _("Broadcasting packet of %d bytes from %s (%s)"),
 			   packet->len, from->name, from->hostname);
 
-	if(from != myself)
+	if(from != myself) {
 		send_packet(myself, packet);
 
+		// In TunnelServer mode, do not forward broadcast packets.
+                // The MST might not be valid and create loops.
+		if(tunnelserver)
+			return;
+	}
+
 	for(node = connection_tree->head; node; node = node->next) {
 		c = node->data;
 
@@ -476,6 +515,30 @@ 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;
@@ -489,7 +552,8 @@ void handle_incoming_vpn_data(int sock)
 	pkt.len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
 
 	if(pkt.len < 0) {
-		logger(LOG_ERR, _("Receiving packet failed: %s"), strerror(errno));
+		if(errno != EAGAIN && errno != EINTR)
+			logger(LOG_ERR, _("Receiving packet failed: %s"), strerror(errno));
 		return;
 	}
 
@@ -498,11 +562,17 @@ 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 ifdebug(PROTOCOL) {
+			hostname = sockaddr2hostname(&from);
+			logger(LOG_WARNING, _("Received UDP packet from unknown source %s"), hostname);
+			free(hostname);
+			return;
+		}
+		else
+			return;
 	}
 
 	receive_udppacket(n, &pkt);