X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=src%2Fprotocol_auth.c;h=be4d2ea084688525e34134ec5204343c56fbfe16;hb=a1b50920b9a52f86ca6e33fcb24d7fa34313a1ee;hp=e5c4c1663d70ad5baff2d845de82e3b773da4d4f;hpb=b58d95eb29662bce4388f95dbc5762b9e2999806;p=meshlink

diff --git a/src/protocol_auth.c b/src/protocol_auth.c
index e5c4c166..be4d2ea0 100644
--- a/src/protocol_auth.c
+++ b/src/protocol_auth.c
@@ -1,7 +1,6 @@
 /*
     protocol_auth.c -- handle the meta-protocol, authentication
-    Copyright (C) 1999-2005 Ivo Timmermans,
-                  2000-2012 Guus Sliepen <guus@tinc-vpn.org>
+    Copyright (C) 2014 Guus Sliepen <guus@meshlink.io>
 
     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
@@ -20,455 +19,336 @@
 
 #include "system.h"
 
-#include <openssl/sha.h>
-#include <openssl/rand.h>
-#include <openssl/err.h>
-#include <openssl/evp.h>
-
-#include "avl_tree.h"
 #include "conf.h"
 #include "connection.h"
+#include "ecdsa.h"
 #include "edge.h"
 #include "graph.h"
 #include "logger.h"
+#include "meshlink_internal.h"
 #include "meta.h"
 #include "net.h"
 #include "netutl.h"
 #include "node.h"
+#include "prf.h"
 #include "protocol.h"
+#include "sptps.h"
 #include "utils.h"
 #include "xalloc.h"
+#include "ed25519/sha512.h"
 
-static bool send_proxyrequest(connection_t *c) {
-	switch(proxytype) {
+static bool send_proxyrequest(meshlink_handle_t *mesh, connection_t *c) {
+	switch(mesh->proxytype) {
 		case PROXY_HTTP: {
 			char *host;
 			char *port;
 
 			sockaddr2str(&c->address, &host, &port);
-			send_request(c, "CONNECT %s:%s HTTP/1.1\r\n\r", host, port);
+			send_request(mesh, c, "CONNECT %s:%s HTTP/1.1\r\n\r", host, port);
 			free(host);
 			free(port);
 			return true;
 		}
 		case PROXY_SOCKS4: {
 			if(c->address.sa.sa_family != AF_INET) {
-				logger(LOG_ERR, "Cannot connect to an IPv6 host through a SOCKS 4 proxy!");
+				logger(DEBUG_ALWAYS, LOG_ERR, "Cannot connect to an IPv6 host through a SOCKS 4 proxy!");
 				return false;
 			}
-			char s4req[9 + (proxyuser ? strlen(proxyuser) : 0)];
+			char s4req[9 + (mesh->proxyuser ? strlen(mesh->proxyuser) : 0)];
 			s4req[0] = 4;
 			s4req[1] = 1;
 			memcpy(s4req + 2, &c->address.in.sin_port, 2);
 			memcpy(s4req + 4, &c->address.in.sin_addr, 4);
-			if(proxyuser)
-				strcpy(s4req + 8, proxyuser);
+			if(mesh->proxyuser)
+				memcpy(s4req + 8, mesh->proxyuser, strlen(mesh->proxyuser));
 			s4req[sizeof s4req - 1] = 0;
 			c->tcplen = 8;
-			return send_meta(c, s4req, sizeof s4req);
+			return send_meta(mesh, c, s4req, sizeof s4req);
+		}
+		case PROXY_SOCKS5: {
+			int len = 3 + 6 + (c->address.sa.sa_family == AF_INET ? 4 : 16);
+			c->tcplen = 2;
+			if(mesh->proxypass)
+				len += 3 + strlen(mesh->proxyuser) + strlen(mesh->proxypass);
+			char s5req[len];
+			int i = 0;
+			s5req[i++] = 5;
+			s5req[i++] = 1;
+			if(mesh->proxypass) {
+				s5req[i++] = 2;
+				s5req[i++] = 1;
+				s5req[i++] = strlen(mesh->proxyuser);
+				memcpy(s5req + i, mesh->proxyuser, strlen(mesh->proxyuser));
+				i += strlen(mesh->proxyuser);
+				s5req[i++] = strlen(mesh->proxypass);
+				memcpy(s5req + i, mesh->proxypass, strlen(mesh->proxypass));
+				i += strlen(mesh->proxypass);
+				c->tcplen += 2;
+			} else {
+				s5req[i++] = 0;
+			}
+			s5req[i++] = 5;
+			s5req[i++] = 1;
+			s5req[i++] = 0;
+			if(c->address.sa.sa_family == AF_INET) {
+				s5req[i++] = 1;
+				memcpy(s5req + i, &c->address.in.sin_addr, 4);
+				i += 4;
+				memcpy(s5req + i, &c->address.in.sin_port, 2);
+				i += 2;
+				c->tcplen += 10;
+			} else if(c->address.sa.sa_family == AF_INET6) {
+				s5req[i++] = 3;
+				memcpy(s5req + i, &c->address.in6.sin6_addr, 16);
+				i += 16;
+				memcpy(s5req + i, &c->address.in6.sin6_port, 2);
+				i += 2;
+				c->tcplen += 22;
+			} else {
+				logger(DEBUG_ALWAYS, LOG_ERR, "Address family %hx not supported for SOCKS 5 proxies!", c->address.sa.sa_family);
+				return false;
+			}
+			if(i > len)
+				abort();
+			return send_meta(mesh, c, s5req, sizeof s5req);
 		}
 		case PROXY_SOCKS4A:
-		case PROXY_SOCKS5:
-			logger(LOG_ERR, "Proxy type not implemented yet");
+			logger(DEBUG_ALWAYS, LOG_ERR, "Proxy type not implemented yet");
 			return false;
+		case PROXY_EXEC:
+			return true;
 		default:
-			logger(LOG_ERR, "Unknown proxy type");
+			logger(DEBUG_ALWAYS, LOG_ERR, "Unknown proxy type");
 			return false;
 	}
 }
 
-bool send_id(connection_t *c) {
-	if(proxytype)
-		if(!send_proxyrequest(c))
+bool send_id(meshlink_handle_t *mesh, connection_t *c) {
+	gettimeofday(&c->start, NULL);
+
+	int minor = mesh->self->connection->protocol_minor;
+
+	if(mesh->proxytype && c->outgoing)
+		if(!send_proxyrequest(mesh, c))
 			return false;
 
-	return send_request(c, "%d %s %d", ID, myself->connection->name,
-						myself->connection->protocol_version);
+	return send_request(mesh, c, "%d %s %d.%d", ID, mesh->self->connection->name, mesh->self->connection->protocol_major, minor);
 }
 
-bool id_h(connection_t *c) {
-	char name[MAX_STRING_SIZE];
-
-	if(sscanf(c->buffer, "%*d " MAX_STRING " %d", name, &c->protocol_version) != 2) {
-		logger(LOG_ERR, "Got bad %s from %s (%s)", "ID", c->name,
-			   c->hostname);
+static bool finalize_invitation(meshlink_handle_t *mesh, connection_t *c, const char *data, uint16_t len) {
+	if(strchr(data, '\n')) {
+		logger(DEBUG_ALWAYS, LOG_ERR, "Received invalid key from invited node %s (%s)!\n", c->name, c->hostname);
 		return false;
 	}
 
-	/* Check if identity is a valid name */
-
-	if(!check_id(name)) {
-		logger(LOG_ERR, "Got bad %s from %s (%s): %s", "ID", c->name,
-			   c->hostname, "invalid name");
+	// Create a new host config file
+	char filename[PATH_MAX];
+	snprintf(filename, sizeof filename, "%s" SLASH "hosts" SLASH "%s", mesh->confbase, c->name);
+	if(!access(filename, F_OK)) {
+		logger(DEBUG_ALWAYS, LOG_ERR, "Host config file for %s (%s) already exists!\n", c->name, c->hostname);
 		return false;
 	}
 
-	/* If this is an outgoing connection, make sure we are connected to the right host */
-
-	if(c->outgoing) {
-		if(strcmp(c->name, name)) {
-			logger(LOG_ERR, "Peer %s is %s instead of %s", c->hostname, name,
-				   c->name);
-			return false;
-		}
-	} else {
-		if(c->name)
-			free(c->name);
-		c->name = xstrdup(name);
-	}
-
-	/* Check if version matches */
-
-	if(c->protocol_version != myself->connection->protocol_version) {
-		logger(LOG_ERR, "Peer %s (%s) uses incompatible version %d",
-			   c->name, c->hostname, c->protocol_version);
+	FILE *f = fopen(filename, "w");
+	if(!f) {
+		logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to create %s: %s\n", filename, strerror(errno));
 		return false;
 	}
 
-	if(bypass_security) {
-		if(!c->config_tree)
-			init_configuration(&c->config_tree);
-		c->allow_request = ACK;
-		return send_ack(c);
-	}
-
-	if(!c->config_tree) {
-		init_configuration(&c->config_tree);
-
-		if(!read_connection_config(c)) {
-			logger(LOG_ERR, "Peer %s had unknown identity (%s)", c->hostname,
-				   c->name);
-			return false;
-		}
-	}
+	fprintf(f, "ECDSAPublicKey = %s\n", data);
+	fclose(f);
 
-	if(!read_rsa_public_key(c)) {
-		return false;
-	}
+	logger(DEBUG_CONNECTIONS, LOG_INFO, "Key succesfully received from %s (%s)", c->name, c->hostname);
 
-	c->allow_request = METAKEY;
+	//TODO: callback to application to inform of an accepted invitation
 
-	return send_metakey(c);
+	sptps_send_record(&c->sptps, 2, data, 0);
+	return true;
 }
 
-bool send_metakey(connection_t *c) {
-	bool x;
-
-	int len = RSA_size(c->rsa_key);
-
-	/* Allocate buffers for the meta key */
-
-	char buffer[2 * len + 1];
-	
-	c->outkey = xrealloc(c->outkey, len);
+static bool receive_invitation_sptps(void *handle, uint8_t type, const char *data, uint16_t len) {
+	connection_t *c = handle;
+	meshlink_handle_t *mesh = c->mesh;
 
-	if(!c->outctx)
-		c->outctx = xmalloc_and_zero(sizeof(*c->outctx));
+	if(type == 128)
+		return true;
 
-	/* Copy random data to the buffer */
+	if(type == 1 && c->status.invitation_used)
+		return finalize_invitation(mesh, c, data, len);
 
-	RAND_pseudo_bytes((unsigned char *)c->outkey, len);
-
-	/* The message we send must be smaller than the modulus of the RSA key.
-	   By definition, for a key of k bits, the following formula holds:
-
-	   2^(k-1) <= modulus < 2^(k)
-
-	   Where ^ means "to the power of", not "xor".
-	   This means that to be sure, we must choose our message < 2^(k-1).
-	   This can be done by setting the most significant bit to zero.
-	 */
-
-	c->outkey[0] &= 0x7F;
-
-	ifdebug(SCARY_THINGS) {
-		bin2hex(c->outkey, buffer, len);
-		buffer[len * 2] = '\0';
-		logger(LOG_DEBUG, "Generated random meta key (unencrypted): %s",
-			   buffer);
-	}
-
-	/* Encrypt the random data
-
-	   We do not use one of the PKCS padding schemes here.
-	   This is allowed, because we encrypt a totally random string
-	   with a length equal to that of the modulus of the RSA key.
-	 */
-
-	if(RSA_public_encrypt(len, (unsigned char *)c->outkey, (unsigned char *)buffer, c->rsa_key, RSA_NO_PADDING) != len) {
-		logger(LOG_ERR, "Error during encryption of meta key for %s (%s)",
-			   c->name, c->hostname);
+	if(type != 0 || len != 18 || c->status.invitation_used)
 		return false;
-	}
-
-	/* Convert the encrypted random data to a hexadecimal formatted string */
-
-	bin2hex(buffer, buffer, len);
-	buffer[len * 2] = '\0';
 
-	/* Send the meta key */
-
-	x = send_request(c, "%d %d %d %d %d %s", METAKEY,
-					 c->outcipher ? c->outcipher->nid : 0,
-					 c->outdigest ? c->outdigest->type : 0, c->outmaclength,
-					 c->outcompression, buffer);
-
-	/* Further outgoing requests are encrypted with the key we just generated */
-
-	if(c->outcipher) {
-		if(!EVP_EncryptInit(c->outctx, c->outcipher,
-					(unsigned char *)c->outkey + len - c->outcipher->key_len,
-					(unsigned char *)c->outkey + len - c->outcipher->key_len -
-					c->outcipher->iv_len)) {
-			logger(LOG_ERR, "Error during initialisation of cipher for %s (%s): %s",
-					c->name, c->hostname, ERR_error_string(ERR_get_error(), NULL));
-			return false;
-		}
-
-		c->status.encryptout = true;
+	// Recover the filename from the cookie and the key
+	char *fingerprint = ecdsa_get_base64_public_key(mesh->invitation_key);
+	char hash[64];
+	char hashbuf[18 + strlen(fingerprint)];
+	char cookie[25];
+	memcpy(hashbuf, data, 18);
+	memcpy(hashbuf + 18, fingerprint, sizeof hashbuf - 18);
+	sha512(hashbuf, sizeof hashbuf, hash);
+	b64encode_urlsafe(hash, cookie, 18);
+	free(fingerprint);
+
+	char filename[PATH_MAX], usedname[PATH_MAX];
+	snprintf(filename, sizeof filename, "%s" SLASH "invitations" SLASH "%s", mesh->confbase, cookie);
+	snprintf(usedname, sizeof usedname, "%s" SLASH "invitations" SLASH "%s.used", mesh->confbase, cookie);
+
+	// Atomically rename the invitation file
+	if(rename(filename, usedname)) {
+		if(errno == ENOENT)
+			logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s tried to use non-existing invitation %s\n", c->hostname, cookie);
+		else
+			logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to rename invitation %s\n", cookie);
+		return false;
 	}
 
-	return x;
-}
-
-bool metakey_h(connection_t *c) {
-	char buffer[MAX_STRING_SIZE];
-	int cipher, digest, maclength, compression;
-	int len;
-
-	if(sscanf(c->buffer, "%*d %d %d %d %d " MAX_STRING, &cipher, &digest, &maclength, &compression, buffer) != 5) {
-		logger(LOG_ERR, "Got bad %s from %s (%s)", "METAKEY", c->name,
-			   c->hostname);
+	// Open the renamed file
+	FILE *f = fopen(usedname, "r");
+	if(!f) {
+		logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to open invitation %s\n", cookie);
 		return false;
 	}
 
-	len = RSA_size(myself->connection->rsa_key);
-
-	/* Check if the length of the meta key is all right */
+	// Read the new node's Name from the file
+	char buf[1024];
+	fgets(buf, sizeof buf, f);
+	if(*buf)
+		buf[strlen(buf) - 1] = 0;
+
+	len = strcspn(buf, " \t=");
+	char *name = buf + len;
+	name += strspn(name, " \t");
+	if(*name == '=') {
+		name++;
+		name += strspn(name, " \t");
+	}
+	buf[len] = 0;
 
-	if(strlen(buffer) != len * 2) {
-		logger(LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong keylength");
+	if(!*buf || !*name || strcasecmp(buf, "Name") || !check_id(name)) {
+		logger(DEBUG_ALWAYS, LOG_ERR, "Invalid invitation file %s\n", cookie);
+		fclose(f);
 		return false;
 	}
 
-	/* Allocate buffers for the meta key */
+	free(c->name);
+	c->name = xstrdup(name);
 
-	c->inkey = xrealloc(c->inkey, len);
+	// Send the node the contents of the invitation file
+	rewind(f);
+	size_t result;
+	while((result = fread(buf, 1, sizeof buf, f)))
+		sptps_send_record(&c->sptps, 0, buf, result);
+	sptps_send_record(&c->sptps, 1, buf, 0);
+	fclose(f);
+	unlink(usedname);
 
-	if(!c->inctx)
-		c->inctx = xmalloc_and_zero(sizeof(*c->inctx));
+	c->status.invitation_used = true;
 
-	/* Convert the challenge from hexadecimal back to binary */
-
-	hex2bin(buffer, buffer, len);
+	logger(DEBUG_CONNECTIONS, LOG_INFO, "Invitation %s succesfully sent to %s (%s)", cookie, c->name, c->hostname);
+	return true;
+}
 
-	/* Decrypt the meta key */
+bool id_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
+	char name[MAX_STRING_SIZE];
 
-	if(RSA_private_decrypt(len, (unsigned char *)buffer, (unsigned char *)c->inkey, myself->connection->rsa_key, RSA_NO_PADDING) != len) {	/* See challenge() */
-		logger(LOG_ERR, "Error during decryption of meta key for %s (%s)",
-			   c->name, c->hostname);
+	if(sscanf(request, "%*d " MAX_STRING " %d.%d", name, &c->protocol_major, &c->protocol_minor) < 2) {
+		logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ID", c->name,
+			   c->hostname);
 		return false;
 	}
 
-	ifdebug(SCARY_THINGS) {
-		bin2hex(c->inkey, buffer, len);
-		buffer[len * 2] = '\0';
-		logger(LOG_DEBUG, "Received random meta key (unencrypted): %s", buffer);
-	}
-
-	/* All incoming requests will now be encrypted. */
-
-	/* Check and lookup cipher and digest algorithms */
+	/* Check if this is an invitation  */
 
-	if(cipher) {
-		c->incipher = EVP_get_cipherbynid(cipher);
-		
-		if(!c->incipher) {
-			logger(LOG_ERR, "%s (%s) uses unknown cipher!", c->name, c->hostname);
+	if(name[0] == '?') {
+		if(!mesh->invitation_key) {
+			logger(DEBUG_ALWAYS, LOG_ERR, "Got invitation from %s but we don't have an invitation key", c->hostname);
 			return false;
 		}
 
-		if(!EVP_DecryptInit(c->inctx, c->incipher,
-					(unsigned char *)c->inkey + len - c->incipher->key_len,
-					(unsigned char *)c->inkey + len - c->incipher->key_len -
-					c->incipher->iv_len)) {
-			logger(LOG_ERR, "Error during initialisation of cipher from %s (%s): %s",
-					c->name, c->hostname, ERR_error_string(ERR_get_error(), NULL));
+		c->ecdsa = ecdsa_set_base64_public_key(name + 1);
+		if(!c->ecdsa) {
+			logger(DEBUG_ALWAYS, LOG_ERR, "Got bad invitation from %s", c->hostname);
 			return false;
 		}
 
-		c->status.decryptin = true;
-	} else {
-		c->incipher = NULL;
-	}
-
-	c->inmaclength = maclength;
-
-	if(digest) {
-		c->indigest = EVP_get_digestbynid(digest);
-
-		if(!c->indigest) {
-			logger(LOG_ERR, "Node %s (%s) uses unknown digest!", c->name, c->hostname);
+		c->status.invitation = true;
+		char *mykey = ecdsa_get_base64_public_key(mesh->invitation_key);
+		if(!mykey)
 			return false;
-		}
-
-		if(c->inmaclength > c->indigest->md_size || c->inmaclength < 0) {
-			logger(LOG_ERR, "%s (%s) uses bogus MAC length!", c->name, c->hostname);
+		if(!send_request(mesh, c, "%d %s", ACK, mykey))
 			return false;
-		}
-	} else {
-		c->indigest = NULL;
-	}
-
-	c->incompression = compression;
+		free(mykey);
 
-	c->allow_request = CHALLENGE;
+		c->protocol_minor = 2;
 
-	return send_challenge(c);
-}
-
-bool send_challenge(connection_t *c) {
-	/* CHECKME: what is most reasonable value for len? */
-
-	int len = RSA_size(c->rsa_key);
-
-	/* Allocate buffers for the challenge */
-
-	char buffer[2 * len + 1];
-
-	c->hischallenge = xrealloc(c->hischallenge, len);
-
-	/* Copy random data to the buffer */
-
-	RAND_pseudo_bytes((unsigned char *)c->hischallenge, len);
-
-	/* Convert to hex */
-
-	bin2hex(c->hischallenge, buffer, len);
-	buffer[len * 2] = '\0';
-
-	/* Send the challenge */
-
-	return send_request(c, "%d %s", CHALLENGE, buffer);
-}
-
-bool challenge_h(connection_t *c) {
-	char buffer[MAX_STRING_SIZE];
-	int len;
-
-	if(sscanf(c->buffer, "%*d " MAX_STRING, buffer) != 1) {
-		logger(LOG_ERR, "Got bad %s from %s (%s)", "CHALLENGE", c->name,
-			   c->hostname);
-		return false;
+		return sptps_start(&c->sptps, c, false, false, mesh->invitation_key, c->ecdsa, "tinc invitation", 15, send_meta_sptps, receive_invitation_sptps);
 	}
 
-	len = RSA_size(myself->connection->rsa_key);
-
-	/* Check if the length of the challenge is all right */
-
-	if(strlen(buffer) != len * 2) {
-		logger(LOG_ERR, "Possible intruder %s (%s): %s", c->name,
-			   c->hostname, "wrong challenge length");
-		return false;
-	}
-
-	/* Allocate buffers for the challenge */
-
-	c->mychallenge = xrealloc(c->mychallenge, len);
-
-	/* Convert the challenge from hexadecimal back to binary */
-
-	hex2bin(buffer, c->mychallenge, len);
-
-	c->allow_request = CHAL_REPLY;
-
-	/* Rest is done by send_chal_reply() */
-
-	return send_chal_reply(c);
-}
-
-bool send_chal_reply(connection_t *c) {
-	char hash[EVP_MAX_MD_SIZE * 2 + 1];
-	EVP_MD_CTX ctx;
-
-	/* Calculate the hash from the challenge we received */
+	/* Check if identity is a valid name */
 
-	if(!EVP_DigestInit(&ctx, c->indigest)
-			|| !EVP_DigestUpdate(&ctx, c->mychallenge, RSA_size(myself->connection->rsa_key))
-			|| !EVP_DigestFinal(&ctx, (unsigned char *)hash, NULL)) {
-		logger(LOG_ERR, "Error during calculation of response for %s (%s): %s",
-			c->name, c->hostname, ERR_error_string(ERR_get_error(), NULL));
+	if(!check_id(name)) {
+		logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ID", c->name,
+			   c->hostname, "invalid name");
 		return false;
 	}
 
-	/* Convert the hash to a hexadecimal formatted string */
-
-	bin2hex(hash, hash, c->indigest->md_size);
-	hash[c->indigest->md_size * 2] = '\0';
-
-	/* Send the reply */
-
-	return send_request(c, "%d %s", CHAL_REPLY, hash);
-}
-
-bool chal_reply_h(connection_t *c) {
-	char hishash[MAX_STRING_SIZE];
-	char myhash[EVP_MAX_MD_SIZE];
-	EVP_MD_CTX ctx;
+	/* If this is an outgoing connection, make sure we are connected to the right host */
 
-	if(sscanf(c->buffer, "%*d " MAX_STRING, hishash) != 1) {
-		logger(LOG_ERR, "Got bad %s from %s (%s)", "CHAL_REPLY", c->name,
-			   c->hostname);
-		return false;
+	if(c->outgoing) {
+		if(strcmp(c->name, name)) {
+			logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s is %s instead of %s", c->hostname, name,
+				   c->name);
+			return false;
+		}
+	} else {
+		if(c->name)
+			free(c->name);
+		c->name = xstrdup(name);
 	}
 
-	/* Check if the length of the hash is all right */
+	/* Check if version matches */
 
-	if(strlen(hishash) != c->outdigest->md_size * 2) {
-		logger(LOG_ERR, "Possible intruder %s (%s): %s", c->name,
-			   c->hostname, "wrong challenge reply length");
+	if(c->protocol_major != mesh->self->connection->protocol_major) {
+		logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) uses incompatible version %d.%d",
+			c->name, c->hostname, c->protocol_major, c->protocol_minor);
 		return false;
 	}
 
-	/* Convert the hash to binary format */
-
-	hex2bin(hishash, hishash, c->outdigest->md_size);
+	if(!c->config_tree) {
+		init_configuration(&c->config_tree);
 
-	/* Calculate the hash from the challenge we sent */
+		if(!read_host_config(mesh, c->config_tree, c->name)) {
+			logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s had unknown identity (%s)", c->hostname, c->name);
+			return false;
+		}
 
-	if(!EVP_DigestInit(&ctx, c->outdigest)
-			|| !EVP_DigestUpdate(&ctx, c->hischallenge, RSA_size(c->rsa_key))
-			|| !EVP_DigestFinal(&ctx, (unsigned char *)myhash, NULL)) {
-		logger(LOG_ERR, "Error during calculation of response from %s (%s): %s",
-			c->name, c->hostname, ERR_error_string(ERR_get_error(), NULL));
-		return false;
+		read_ecdsa_public_key(mesh, c);
+	} else {
+		if(c->protocol_minor && !ecdsa_active(c->ecdsa))
+			c->protocol_minor = 1;
 	}
 
-	/* Verify the incoming hash with the calculated hash */
-
-	if(memcmp(hishash, myhash, c->outdigest->md_size)) {
-		logger(LOG_ERR, "Possible intruder %s (%s): %s", c->name,
-			   c->hostname, "wrong challenge reply");
-
-		ifdebug(SCARY_THINGS) {
-			bin2hex(myhash, hishash, SHA_DIGEST_LENGTH);
-			hishash[SHA_DIGEST_LENGTH * 2] = '\0';
-			logger(LOG_DEBUG, "Expected challenge reply: %s", hishash);
-		}
+	/* Forbid version rollback for nodes whose ECDSA key we know */
 
+	if(ecdsa_active(c->ecdsa) && c->protocol_minor < 2) {
+		logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) tries to roll back protocol version to %d.%d",
+			c->name, c->hostname, c->protocol_major, c->protocol_minor);
 		return false;
 	}
 
-	/* Identity has now been positively verified.
-	   Send an acknowledgement with the rest of the information needed.
-	 */
-
 	c->allow_request = ACK;
+	char label[25 + strlen(mesh->self->name) + strlen(c->name)];
+
+	if(c->outgoing)
+		snprintf(label, sizeof label, "tinc TCP key expansion %s %s", mesh->self->name, c->name);
+	else
+		snprintf(label, sizeof label, "tinc TCP key expansion %s %s", c->name, mesh->self->name);
 
-	return send_ack(c);
+	return sptps_start(&c->sptps, c, c->outgoing, false, mesh->self->connection->ecdsa, c->ecdsa, label, sizeof label, send_meta_sptps, receive_meta_sptps);
 }
 
-bool send_ack(connection_t *c) {
+bool send_ack(meshlink_handle_t *mesh, connection_t *c) {
 	/* ACK message contains rest of the information the other end needs
 	   to create node_t and edge_t structures. */
 
@@ -482,58 +362,22 @@ bool send_ack(connection_t *c) {
 
 	/* Check some options */
 
-	if((get_config_bool(lookup_config(c->config_tree, "IndirectData"), &choice) && choice) || myself->options & OPTION_INDIRECT)
-		c->options |= OPTION_INDIRECT;
-
-	if((get_config_bool(lookup_config(c->config_tree, "TCPOnly"), &choice) && choice) || myself->options & OPTION_TCPONLY)
-		c->options |= OPTION_TCPONLY | OPTION_INDIRECT;
-
-	if(myself->options & OPTION_PMTU_DISCOVERY)
+	if(mesh->self->options & OPTION_PMTU_DISCOVERY)
 		c->options |= OPTION_PMTU_DISCOVERY;
 
-	choice = myself->options & OPTION_CLAMP_MSS;
-	get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice);
-	if(choice)
-		c->options |= OPTION_CLAMP_MSS;
-
-	get_config_int(lookup_config(c->config_tree, "Weight"), &c->estimated_weight);
-
-	return send_request(c, "%d %s %d %x", ACK, myport, c->estimated_weight, c->options);
+	return send_request(mesh, c, "%d %s %d %x", ACK, mesh->myport, c->estimated_weight, (c->options & 0xffffff) | (PROT_MINOR << 24));
 }
 
-static void send_everything(connection_t *c) {
-	avl_node_t *node, *node2;
-	node_t *n;
-	subnet_t *s;
-	edge_t *e;
-
+static void send_everything(meshlink_handle_t *mesh, connection_t *c) {
 	/* Send all known subnets and edges */
 
-	if(tunnelserver) {
-		for(node = myself->subnet_tree->head; node; node = node->next) {
-			s = node->data;
-			send_add_subnet(c, s);
-		}
-
-		return;
-	}
-
-	for(node = node_tree->head; node; node = node->next) {
-		n = node->data;
-
-		for(node2 = n->subnet_tree->head; node2; node2 = node2->next) {
-			s = node2->data;
-			send_add_subnet(c, s);
-		}
-
-		for(node2 = n->edge_tree->head; node2; node2 = node2->next) {
-			e = node2->data;
-			send_add_edge(c, e);
-		}
+	for splay_each(node_t, n, mesh->nodes) {
+		for splay_each(edge_t, e, n->edge_tree)
+			send_add_edge(mesh, c, e);
 	}
 }
 
-bool ack_h(connection_t *c) {
+bool ack_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
 	char hisport[MAX_STRING_SIZE];
 	char *hisaddress;
 	int weight, mtu;
@@ -541,28 +385,37 @@ bool ack_h(connection_t *c) {
 	node_t *n;
 	bool choice;
 
-	if(sscanf(c->buffer, "%*d " MAX_STRING " %d %x", hisport, &weight, &options) != 3) {
-		logger(LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name,
+	if(sscanf(request, "%*d " MAX_STRING " %d %x", hisport, &weight, &options) != 3) {
+		logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name,
 			   c->hostname);
 		return false;
 	}
 
 	/* Check if we already have a node_t for him */
 
-	n = lookup_node(c->name);
+	n = lookup_node(mesh, c->name);
 
 	if(!n) {
 		n = new_node();
 		n->name = xstrdup(c->name);
-		node_add(n);
+		node_add(mesh, n);
 	} else {
 		if(n->connection) {
 			/* Oh dear, we already have a connection to this node. */
-			ifdebug(CONNECTIONS) logger(LOG_DEBUG, "Established a second connection with %s (%s), closing old connection",
-					   n->name, n->hostname);
-			terminate_connection(n->connection, false);
-			/* Run graph algorithm to purge key and make sure up/down scripts are rerun with new IP addresses and stuff */
-			graph();
+			logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Established a second connection with %s (%s), closing old connection", n->connection->name, n->connection->hostname);
+
+			if(n->connection->outgoing) {
+				if(c->outgoing)
+					logger(DEBUG_ALWAYS, LOG_WARNING, "Two outgoing connections to the same node!");
+				else
+					c->outgoing = n->connection->outgoing;
+
+				n->connection->outgoing = NULL;
+			}
+
+			terminate_connection(mesh, n->connection, false);
+			/* Run graph algorithm to keep things in sync */
+			graph(mesh);
 		}
 	}
 
@@ -574,35 +427,22 @@ bool ack_h(connection_t *c) {
 	}
 	c->options |= options;
 
-	if(get_config_int(lookup_config(c->config_tree, "PMTU"), &mtu) && mtu < n->mtu)
-		n->mtu = mtu;
-
-	if(get_config_int(lookup_config(config_tree, "PMTU"), &mtu) && mtu < n->mtu)
-		n->mtu = mtu;
-
-	if(get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice)) {
-		if(choice)
-			c->options |= OPTION_CLAMP_MSS;
-		else
-			c->options &= ~OPTION_CLAMP_MSS;
-	}
-
 	/* Activate this connection */
 
 	c->allow_request = ALL;
 	c->status.active = true;
 
-	ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection with %s (%s) activated", c->name,
+	logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection with %s (%s) activated", c->name,
 			   c->hostname);
 
 	/* Send him everything we know */
 
-	send_everything(c);
+	send_everything(mesh, c);
 
 	/* Create an edge_t for this connection */
 
 	c->edge = new_edge();
-	c->edge->from = myself;
+	c->edge->from = mesh->self;
 	c->edge->to = n;
 	sockaddr2str(&c->address, &hisaddress, NULL);
 	c->edge->address = str2sockaddr(hisaddress, hisport);
@@ -611,18 +451,15 @@ bool ack_h(connection_t *c) {
 	c->edge->connection = c;
 	c->edge->options = c->options;
 
-	edge_add(c->edge);
+	edge_add(mesh, c->edge);
 
 	/* Notify everyone of the new edge */
 
-	if(tunnelserver)
-		send_add_edge(c, c->edge);
-	else
-		send_add_edge(everyone, c->edge);
+	send_add_edge(mesh, mesh->everyone, c->edge);
 
 	/* Run MST and SSSP algorithms */
 
-	graph();
+	graph(mesh);
 
 	return true;
 }