X-Git-Url: https://tinc-vpn.org/git/browse?a=blobdiff_plain;f=src%2Fprotocol_key.c;h=a0a184622b98c650decea8d8b4b556f395905cc3;hb=e88b3fb52fb375cd8ab233a671f38ed2240ed828;hp=ebc46f32ae3bf57559ecb0d90938d7e8390e66f8;hpb=63daebcd1ec2975c0c2ad8e0ee0fced33b1fbbf0;p=tinc

diff --git a/src/protocol_key.c b/src/protocol_key.c
index ebc46f32..a0a18462 100644
--- a/src/protocol_key.c
+++ b/src/protocol_key.c
@@ -1,7 +1,7 @@
 /*
     protocol_key.c -- handle the meta-protocol, key exchange
     Copyright (C) 1999-2005 Ivo Timmermans,
-                  2000-2013 Guus Sliepen <guus@tinc-vpn.org>
+                  2000-2017 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
@@ -29,6 +29,7 @@
 #include "node.h"
 #include "prf.h"
 #include "protocol.h"
+#include "route.h"
 #include "sptps.h"
 #include "utils.h"
 #include "xalloc.h"
@@ -36,20 +37,25 @@
 static bool mykeyused = false;
 
 void send_key_changed(void) {
+#ifndef DISABLE_LEGACY
 	send_request(everyone, "%d %x %s", KEY_CHANGED, rand(), myself->name);
 
 	/* Immediately send new keys to directly connected nodes to keep UDP mappings alive */
 
 	for list_each(connection_t, c, connection_list)
-		if(c->edge && c->node && c->node->status.reachable && !c->node->status.sptps)
+		if(c->edge && c->node && c->node->status.reachable && !c->node->status.sptps) {
 			send_ans_key(c->node);
+		}
+
+#endif
 
 	/* Force key exchange for connections using SPTPS */
 
 	if(experimental) {
 		for splay_each(node_t, n, node_tree)
-			if(n->status.reachable && n->status.validkey && n->status.sptps)
+			if(n->status.reachable && n->status.validkey && n->status.sptps) {
 				sptps_force_kex(&n->sptps);
+			}
 	}
 }
 
@@ -59,18 +65,19 @@ bool key_changed_h(connection_t *c, const char *request) {
 
 	if(sscanf(request, "%*d %*x " MAX_STRING, name) != 1) {
 		logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "KEY_CHANGED",
-			   c->name, c->hostname);
+		       c->name, c->hostname);
 		return false;
 	}
 
-	if(seen_request(request))
+	if(seen_request(request)) {
 		return true;
+	}
 
 	n = lookup_node(name);
 
 	if(!n) {
 		logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist",
-			   "KEY_CHANGED", c->name, c->hostname, name);
+		       "KEY_CHANGED", c->name, c->hostname, name);
 		return true;
 	}
 
@@ -81,15 +88,20 @@ bool key_changed_h(connection_t *c, const char *request) {
 
 	/* Tell the others */
 
-	if(!tunnelserver)
+	if(!tunnelserver) {
 		forward_request(c, request);
+	}
 
 	return true;
 }
 
-static bool send_initial_sptps_data(void *handle, uint8_t type, const char *data, size_t len) {
+static bool send_sptps_data_myself(void *handle, uint8_t type, const void *data, size_t len) {
+	return send_sptps_data(handle, myself, type, data, len);
+}
+
+static bool send_initial_sptps_data(void *handle, uint8_t type, const void *data, size_t len) {
 	node_t *to = handle;
-	to->sptps.send_data = send_sptps_data;
+	to->sptps.send_data = send_sptps_data_myself;
 	char buf[len * 4 / 3 + 5];
 	b64encode(data, buf, len);
 	return send_request(to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, to->name, REQ_KEY, buf);
@@ -103,17 +115,14 @@ bool send_req_key(node_t *to) {
 			return true;
 		}
 
-		if(to->sptps.label)
-			logger(DEBUG_ALWAYS, LOG_DEBUG, "send_req_key(%s) called while sptps->label != NULL!", to->name);
-
 		char label[25 + strlen(myself->name) + strlen(to->name)];
-		snprintf(label, sizeof label, "tinc UDP key expansion %s %s", myself->name, to->name);
+		snprintf(label, sizeof(label), "tinc UDP key expansion %s %s", myself->name, to->name);
 		sptps_stop(&to->sptps);
 		to->status.validkey = false;
 		to->status.waitingforkey = true;
 		to->last_req_key = now.tv_sec;
 		to->incompression = myself->incompression;
-		return sptps_start(&to->sptps, to, true, true, myself->connection->ecdsa, to->ecdsa, label, sizeof label, send_initial_sptps_data, receive_sptps_record);
+		return sptps_start(&to->sptps, to, true, true, myself->connection->ecdsa, to->ecdsa, label, sizeof(label), send_initial_sptps_data, receive_sptps_record);
 	}
 
 	return send_request(to->nexthop->connection, "%d %s %s", REQ_KEY, myself->name, to->name);
@@ -121,85 +130,125 @@ bool send_req_key(node_t *to) {
 
 /* REQ_KEY is overloaded to allow arbitrary requests to be routed between two nodes. */
 
-static bool req_key_ext_h(connection_t *c, const char *request, node_t *from, int reqno) {
-	switch(reqno) {
-		case REQ_PUBKEY: {
-			if(!node_read_ecdsa_public_key(from)) {
-				/* Request their key *before* we send our key back. Otherwise the first SPTPS packet from them will get dropped. */
-				logger(DEBUG_PROTOCOL, LOG_DEBUG, "Preemptively requesting Ed25519 key for %s (%s)", from->name, from->hostname);
-				send_request(from->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, from->name, REQ_PUBKEY);
-			}
-			char *pubkey = ecdsa_get_base64_public_key(myself->connection->ecdsa);
-			send_request(from->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, from->name, ANS_PUBKEY, pubkey);
-			free(pubkey);
+static bool req_key_ext_h(connection_t *c, const char *request, node_t *from, node_t *to, int reqno) {
+	/* If this is a SPTPS packet, see if sending UDP info helps.
+	   Note that we only do this if we're the destination or the static relay;
+	   otherwise every hop would initiate its own UDP info message, resulting in elevated chatter. */
+	if((reqno == REQ_KEY || reqno == SPTPS_PACKET) && to->via == myself) {
+		send_udp_info(myself, from);
+	}
+
+	if(reqno == SPTPS_PACKET) {
+		/* This is a SPTPS data packet. */
+
+		char buf[MAX_STRING_SIZE];
+		int len;
+
+		if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
+			logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s) to %s (%s): %s", "SPTPS_PACKET", from->name, from->hostname, to->name, to->hostname, "invalid SPTPS data");
 			return true;
 		}
 
-		case ANS_PUBKEY: {
-			if(node_read_ecdsa_public_key(from)) {
-				logger(DEBUG_PROTOCOL, LOG_WARNING, "Got ANS_PUBKEY from %s (%s) even though we already have his pubkey", from->name, from->hostname);
-				return true;
+		if(to != myself) {
+			/* We don't just forward the request, because we want to use UDP if it's available. */
+			if(forwarding_mode == FMODE_INTERNAL) {
+				send_sptps_data(to, from, 0, buf, len);
+				try_tx(to, true);
 			}
+		} else {
+			/* The packet is for us */
+			if(!sptps_receive_data(&from->sptps, buf, len)) {
+				/* Uh-oh. It might be that the tunnel is stuck in some corrupted state,
+				   so let's restart SPTPS in case that helps. But don't do that too often
+				   to prevent storms. */
+				if(from->last_req_key < now.tv_sec - 10) {
+					logger(DEBUG_PROTOCOL, LOG_ERR, "Failed to decode TCP packet from %s (%s), restarting SPTPS", from->name, from->hostname);
+					send_req_key(from);
+				}
 
-			char pubkey[MAX_STRING_SIZE];
-			if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !(from->ecdsa = ecdsa_set_base64_public_key(pubkey))) {
-				logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_PUBKEY", from->name, from->hostname, "invalid pubkey");
 				return true;
 			}
 
-			logger(DEBUG_PROTOCOL, LOG_INFO, "Learned Ed25519 public key from %s (%s)", from->name, from->hostname);
-			append_config_file(from->name, "Ed25519PublicKey", pubkey);
-			return true;
+			send_mtu_info(myself, from, MTU);
 		}
 
-		case REQ_KEY: {
-			if(!node_read_ecdsa_public_key(from)) {
-				logger(DEBUG_PROTOCOL, LOG_DEBUG, "No Ed25519 key known for %s (%s)", from->name, from->hostname);
-				send_request(from->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, from->name, REQ_PUBKEY);
-				return true;
-			}
+		return true;
+	}
 
-			if(from->sptps.label)
-				logger(DEBUG_ALWAYS, LOG_DEBUG, "Got REQ_KEY from %s while we already started a SPTPS session!", from->name);
+	/* Requests that are not SPTPS data packets are forwarded as-is. */
 
-			char buf[MAX_STRING_SIZE];
-			int len;
+	if(to != myself) {
+		return send_request(to->nexthop->connection, "%s", request);
+	}
 
-			if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
-				logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_SPTPS_START", from->name, from->hostname, "invalid SPTPS data");
-				return true;
-			}
+	/* The request is for us */
+
+	switch(reqno) {
+	case REQ_PUBKEY: {
+		if(!node_read_ecdsa_public_key(from)) {
+			/* Request their key *before* we send our key back. Otherwise the first SPTPS packet from them will get dropped. */
+			logger(DEBUG_PROTOCOL, LOG_DEBUG, "Preemptively requesting Ed25519 key for %s (%s)", from->name, from->hostname);
+			send_request(from->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, from->name, REQ_PUBKEY);
+		}
+
+		char *pubkey = ecdsa_get_base64_public_key(myself->connection->ecdsa);
+		send_request(from->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, from->name, ANS_PUBKEY, pubkey);
+		free(pubkey);
+		return true;
+	}
 
-			char label[25 + strlen(from->name) + strlen(myself->name)];
-			snprintf(label, sizeof label, "tinc UDP key expansion %s %s", from->name, myself->name);
-			sptps_stop(&from->sptps);
-			from->status.validkey = false;
-			from->status.waitingforkey = true;
-			from->last_req_key = now.tv_sec;
-			sptps_start(&from->sptps, from, false, true, myself->connection->ecdsa, from->ecdsa, label, sizeof label, send_sptps_data, receive_sptps_record);
-			sptps_receive_data(&from->sptps, buf, len);
+	case ANS_PUBKEY: {
+		if(node_read_ecdsa_public_key(from)) {
+			logger(DEBUG_PROTOCOL, LOG_WARNING, "Got ANS_PUBKEY from %s (%s) even though we already have his pubkey", from->name, from->hostname);
 			return true;
 		}
 
-		case REQ_SPTPS: {
-			if(!from->status.validkey) {
-				logger(DEBUG_PROTOCOL, LOG_ERR, "Got REQ_SPTPS from %s (%s) but we don't have a valid key yet", from->name, from->hostname);
-				return true;
-			}
+		char pubkey[MAX_STRING_SIZE];
 
-			char buf[MAX_STRING_SIZE];
-			int len;
-			if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
-				logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_SPTPS", from->name, from->hostname, "invalid SPTPS data");
-				return true;
-			}
-			sptps_receive_data(&from->sptps, buf, len);
+		if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !(from->ecdsa = ecdsa_set_base64_public_key(pubkey))) {
+			logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_PUBKEY", from->name, from->hostname, "invalid pubkey");
 			return true;
 		}
 
-		default:
-			logger(DEBUG_ALWAYS, LOG_ERR, "Unknown extended REQ_KEY request from %s (%s): %s", from->name, from->hostname, request);
+		logger(DEBUG_PROTOCOL, LOG_INFO, "Learned Ed25519 public key from %s (%s)", from->name, from->hostname);
+		append_config_file(from->name, "Ed25519PublicKey", pubkey);
+		return true;
+	}
+
+	case REQ_KEY: {
+		if(!node_read_ecdsa_public_key(from)) {
+			logger(DEBUG_PROTOCOL, LOG_DEBUG, "No Ed25519 key known for %s (%s)", from->name, from->hostname);
+			send_request(from->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, from->name, REQ_PUBKEY);
 			return true;
+		}
+
+		if(from->sptps.label) {
+			logger(DEBUG_ALWAYS, LOG_DEBUG, "Got REQ_KEY from %s while we already started a SPTPS session!", from->name);
+		}
+
+		char buf[MAX_STRING_SIZE];
+		int len;
+
+		if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
+			logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_SPTPS_START", from->name, from->hostname, "invalid SPTPS data");
+			return true;
+		}
+
+		char label[25 + strlen(from->name) + strlen(myself->name)];
+		snprintf(label, sizeof(label), "tinc UDP key expansion %s %s", from->name, myself->name);
+		sptps_stop(&from->sptps);
+		from->status.validkey = false;
+		from->status.waitingforkey = true;
+		from->last_req_key = now.tv_sec;
+		sptps_start(&from->sptps, from, false, true, myself->connection->ecdsa, from->ecdsa, label, sizeof(label), send_sptps_data_myself, receive_sptps_record);
+		sptps_receive_data(&from->sptps, buf, len);
+		send_mtu_info(myself, from, MTU);
+		return true;
+	}
+
+	default:
+		logger(DEBUG_ALWAYS, LOG_ERR, "Unknown extended REQ_KEY request from %s (%s): %s", from->name, from->hostname, request);
+		return true;
 	}
 }
 
@@ -211,7 +260,7 @@ bool req_key_h(connection_t *c, const char *request) {
 
 	if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &reqno) < 2) {
 		logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "REQ_KEY", c->name,
-			   c->hostname);
+		       c->hostname);
 		return false;
 	}
 
@@ -224,7 +273,7 @@ bool req_key_h(connection_t *c, const char *request) {
 
 	if(!from) {
 		logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
-			   "REQ_KEY", c->name, c->hostname, from_name);
+		       "REQ_KEY", c->name, c->hostname, from_name);
 		return true;
 	}
 
@@ -232,7 +281,7 @@ bool req_key_h(connection_t *c, const char *request) {
 
 	if(!to) {
 		logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
-			   "REQ_KEY", c->name, c->hostname, to_name);
+		       "REQ_KEY", c->name, c->hostname, to_name);
 		return true;
 	}
 
@@ -240,22 +289,28 @@ bool req_key_h(connection_t *c, const char *request) {
 
 	if(to == myself) {                      /* Yes */
 		/* Is this an extended REQ_KEY message? */
-		if(experimental && reqno)
-			return req_key_ext_h(c, request, from, reqno);
+		if(experimental && reqno) {
+			return req_key_ext_h(c, request, from, to, reqno);
+		}
 
 		/* No, just send our key back */
 		send_ans_key(from);
 	} else {
-		if(tunnelserver)
+		if(tunnelserver) {
 			return true;
+		}
 
 		if(!to->status.reachable) {
 			logger(DEBUG_PROTOCOL, LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
-				"REQ_KEY", c->name, c->hostname, to_name);
+			       "REQ_KEY", c->name, c->hostname, to_name);
 			return true;
 		}
 
-		/* TODO: forwarding SPTPS packets in this way is inefficient because we send them over TCP without checking for UDP connectivity */
+		/* Is this an extended REQ_KEY message? */
+		if(experimental && reqno) {
+			return req_key_ext_h(c, request, from, to, reqno);
+		}
+
 		send_request(to->nexthop->connection, "%s", request);
 	}
 
@@ -263,9 +318,13 @@ bool req_key_h(connection_t *c, const char *request) {
 }
 
 bool send_ans_key(node_t *to) {
-	if(to->status.sptps)
+	if(to->status.sptps) {
 		abort();
+	}
 
+#ifdef DISABLE_LEGACY
+	return false;
+#else
 	size_t keylen = myself->incipher ? cipher_keylength(myself->incipher) : 1;
 	char key[keylen * 2 + 1];
 
@@ -276,18 +335,26 @@ bool send_ans_key(node_t *to) {
 
 	if(myself->incipher) {
 		to->incipher = cipher_open_by_nid(cipher_get_nid(myself->incipher));
-		if(!to->incipher)
+
+		if(!to->incipher) {
 			abort();
-		if(!cipher_set_key(to->incipher, key, false))
+		}
+
+		if(!cipher_set_key(to->incipher, key, false)) {
 			abort();
+		}
 	}
 
 	if(myself->indigest) {
 		to->indigest = digest_open_by_nid(digest_get_nid(myself->indigest), digest_length(myself->indigest));
-		if(!to->indigest)
+
+		if(!to->indigest) {
 			abort();
-		if(!digest_set_key(to->indigest, key, keylen))
+		}
+
+		if(!digest_set_key(to->indigest, key, keylen)) {
 			abort();
+		}
 	}
 
 	to->incompression = myself->incompression;
@@ -298,14 +365,20 @@ bool send_ans_key(node_t *to) {
 	mykeyused = true;
 	to->received_seqno = 0;
 	to->received = 0;
-	if(replaywin) memset(to->late, 0, replaywin);
+
+	if(replaywin) {
+		memset(to->late, 0, replaywin);
+	}
+
+	to->status.validkey_in = true;
 
 	return send_request(to->nexthop->connection, "%d %s %s %s %d %d %d %d", ANS_KEY,
-						myself->name, to->name, key,
-						cipher_get_nid(to->incipher),
-						digest_get_nid(to->indigest),
-						(int)digest_length(to->indigest),
-						to->incompression);
+	                    myself->name, to->name, key,
+	                    cipher_get_nid(to->incipher),
+	                    digest_get_nid(to->indigest),
+	                    (int)digest_length(to->indigest),
+	                    to->incompression);
+#endif
 }
 
 bool ans_key_h(connection_t *c, const char *request) {
@@ -314,14 +387,14 @@ bool ans_key_h(connection_t *c, const char *request) {
 	char key[MAX_STRING_SIZE];
 	char address[MAX_STRING_SIZE] = "";
 	char port[MAX_STRING_SIZE] = "";
-	int cipher, digest, maclength, compression, keylen;
+	int cipher, digest, maclength, compression;
 	node_t *from, *to;
 
 	if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING,
-		from_name, to_name, key, &cipher, &digest, &maclength,
-		&compression, address, port) < 7) {
+	                from_name, to_name, key, &cipher, &digest, &maclength,
+	                &compression, address, port) < 7) {
 		logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ANS_KEY", c->name,
-			   c->hostname);
+		       c->hostname);
 		return false;
 	}
 
@@ -334,7 +407,7 @@ bool ans_key_h(connection_t *c, const char *request) {
 
 	if(!from) {
 		logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
-			   "ANS_KEY", c->name, c->hostname, from_name);
+		       "ANS_KEY", c->name, c->hostname, from_name);
 		return true;
 	}
 
@@ -342,23 +415,24 @@ bool ans_key_h(connection_t *c, const char *request) {
 
 	if(!to) {
 		logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
-			   "ANS_KEY", c->name, c->hostname, to_name);
+		       "ANS_KEY", c->name, c->hostname, to_name);
 		return true;
 	}
 
 	/* Forward it if necessary */
 
 	if(to != myself) {
-		if(tunnelserver)
+		if(tunnelserver) {
 			return true;
+		}
 
 		if(!to->status.reachable) {
 			logger(DEBUG_ALWAYS, LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
-				   "ANS_KEY", c->name, c->hostname, to_name);
+			       "ANS_KEY", c->name, c->hostname, to_name);
 			return true;
 		}
 
-		if(!*address && from->address.sa.sa_family != AF_UNSPEC) {
+		if(!*address && from->address.sa.sa_family != AF_UNSPEC && to->minmtu) {
 			char *address, *port;
 			logger(DEBUG_PROTOCOL, LOG_DEBUG, "Appending reflexive UDP address to ANS_KEY from %s to %s", from->name, to->name);
 			sockaddr2str(&from->address, &address, &port);
@@ -371,10 +445,15 @@ bool ans_key_h(connection_t *c, const char *request) {
 		return send_request(to->nexthop->connection, "%s", request);
 	}
 
+#ifndef DISABLE_LEGACY
 	/* Don't use key material until every check has passed. */
 	cipher_close(from->outcipher);
 	digest_close(from->outdigest);
-	from->status.validkey = false;
+#endif
+
+	if(!from->status.sptps) {
+		from->status.validkey = false;
+	}
 
 	if(compression < 0 || compression > 11) {
 		logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus compression level!", from->name, from->hostname);
@@ -389,8 +468,19 @@ bool ans_key_h(connection_t *c, const char *request) {
 		char buf[strlen(key)];
 		int len = b64decode(key, buf, strlen(key));
 
-		if(!len || !sptps_receive_data(&from->sptps, buf, len))
-			logger(DEBUG_ALWAYS, LOG_ERR, "Error processing SPTPS data from %s (%s)", from->name, from->hostname);
+		if(!len || !sptps_receive_data(&from->sptps, buf, len)) {
+			/* Uh-oh. It might be that the tunnel is stuck in some corrupted state,
+			   so let's restart SPTPS in case that helps. But don't do that too often
+			   to prevent storms.
+			   Note that simply relying on handshake timeout is not enough, because
+			   that doesn't apply to key regeneration. */
+			if(from->last_req_key < now.tv_sec - 10) {
+				logger(DEBUG_PROTOCOL, LOG_ERR, "Failed to decode handshake TCP packet from %s (%s), restarting SPTPS", from->name, from->hostname);
+				send_req_key(from);
+			}
+
+			return true;
+		}
 
 		if(from->status.validkey) {
 			if(*address && *port) {
@@ -398,16 +488,17 @@ bool ans_key_h(connection_t *c, const char *request) {
 				sockaddr_t sa = str2sockaddr(address, port);
 				update_node_udp(from, &sa);
 			}
-
-			/* Don't send probes if we can't send UDP packets directly to that node.
-			   TODO: the indirect (via) condition can change at any time as edges are added and removed, so this should probably be moved to graph.c. */
-			if((from->via == myself || from->via == from) && from->options & OPTION_PMTU_DISCOVERY && !(from->options & OPTION_TCPONLY))
-				send_mtu_probe(from);
 		}
 
+		send_mtu_info(myself, from, MTU);
+
 		return true;
 	}
 
+#ifdef DISABLE_LEGACY
+	logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses legacy protocol!", from->name, from->hostname);
+	return false;
+#else
 	/* Check and lookup cipher and digest algorithms */
 
 	if(cipher) {
@@ -435,7 +526,7 @@ bool ans_key_h(connection_t *c, const char *request) {
 
 	/* Process key */
 
-	keylen = hex2bin(key, key, sizeof key);
+	int keylen = hex2bin(key, key, sizeof(key));
 
 	if(keylen != (from->outcipher ? cipher_keylength(from->outcipher) : 1)) {
 		logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses wrong keylength!", from->name, from->hostname);
@@ -444,10 +535,13 @@ bool ans_key_h(connection_t *c, const char *request) {
 
 	/* Update our copy of the origin's packet key */
 
-	if(from->outcipher && !cipher_set_key(from->outcipher, key, true))
+	if(from->outcipher && !cipher_set_key(from->outcipher, key, true)) {
 		return false;
-	if(from->outdigest && !digest_set_key(from->outdigest, key, keylen))
+	}
+
+	if(from->outdigest && !digest_set_key(from->outdigest, key, keylen)) {
 		return false;
+	}
 
 	from->status.validkey = true;
 	from->sent_seqno = 0;
@@ -458,8 +552,6 @@ bool ans_key_h(connection_t *c, const char *request) {
 		update_node_udp(from, &sa);
 	}
 
-	if(from->options & OPTION_PMTU_DISCOVERY && !(from->options & OPTION_TCPONLY))
-		send_mtu_probe(from);
-
 	return true;
+#endif
 }