+/* The authentication protocol is described in detail in doc/SECURITY2,
+ the rest will be described in doc/PROTOCOL. */
+
+int send_id(connection_t *c)
+{
+cp
+ return send_request(c, "%d %s %d", ID, myself->connection->name, myself->connection->protocol_version);
+}
+
+int id_h(connection_t *c)
+{
+ char name[MAX_STRING_SIZE];
+int bla;
+cp
+ if(sscanf(c->buffer, "%*d "MAX_STRING" %d", name, &c->protocol_version) != 2)
+ {
+ syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "ID", c->name, c->hostname);
+ return -1;
+ }
+
+ /* Check if identity is a valid name */
+
+ if(check_id(name))
+ {
+ syslog(LOG_ERR, _("Got bad %s from %s (%s): %s"), "ID", c->name, c->hostname, "invalid name");
+ return -1;
+ }
+
+ /* If we set c->name in advance, make sure we are connected to the right host */
+
+ if(c->name)
+ {
+ if(strcmp(c->name, name))
+ {
+ syslog(LOG_ERR, _("Peer %s is %s instead of %s"), c->hostname, name, c->name);
+ return -1;
+ }
+ }
+ else
+ c->name = xstrdup(name);
+
+ /* Check if version matches */
+
+ if(c->protocol_version != myself->connection->protocol_version)
+ {
+ syslog(LOG_ERR, _("Peer %s (%s) uses incompatible version %d"),
+ c->name, c->hostname, c->protocol_version);
+ return -1;
+ }
+
+ 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((bla = read_connection_config(c)))
+ {
+ syslog(LOG_ERR, _("Peer %s had unknown identity (%s)"), c->hostname, c->name);
+ return -1;
+ }
+ }
+
+ if(read_rsa_public_key(c))
+ {
+ return -1;
+ }
+
+ c->allow_request = METAKEY;
+cp
+ return send_metakey(c);
+}
+
+int send_metakey(connection_t *c)
+{
+ char *buffer;
+ int len, x;
+cp
+ len = RSA_size(c->rsa_key);
+
+ /* Allocate buffers for the meta key */
+
+ buffer = xmalloc(len*2+1);
+
+ if(!c->outkey)
+ c->outkey = xmalloc(len);
+
+ if(!c->outctx)
+ c->outctx = xmalloc(sizeof(*c->outctx));
+cp
+ /* Copy random data to the buffer */
+
+ RAND_bytes(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;
+
+ if(debug_lvl >= DEBUG_SCARY_THINGS)
+ {
+ bin2hex(c->outkey, buffer, len);
+ buffer[len*2] = '\0';
+ syslog(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, c->outkey, buffer, c->rsa_key, RSA_NO_PADDING) != len)
+ {
+ syslog(LOG_ERR, _("Error during encryption of meta key for %s (%s)"), c->name, c->hostname);
+ free(buffer);
+ return -1;
+ }
+cp
+ /* 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 %s", METAKEY, buffer);
+ free(buffer);
+
+ /* Further outgoing requests are encrypted with the key we just generated */
+
+ EVP_EncryptInit(c->outctx, EVP_bf_cfb(),
+ c->outkey + len - EVP_bf_cfb()->key_len,
+ c->outkey + len - EVP_bf_cfb()->key_len - EVP_bf_cfb()->iv_len);
+
+ c->status.encryptout = 1;
+cp
+ return x;
+}
+
+int metakey_h(connection_t *c)
+{
+ char buffer[MAX_STRING_SIZE];
+ int len;
+cp
+ if(sscanf(c->buffer, "%*d "MAX_STRING, buffer) != 1)
+ {
+ syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "METAKEY", c->name, c->hostname);
+ return -1;
+ }
+
+ len = RSA_size(myself->connection->rsa_key);
+
+ /* Check if the length of the meta key is all right */
+
+ if(strlen(buffer) != len*2)
+ {
+ syslog(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, "wrong keylength");
+ return -1;
+ }
+
+ /* Allocate buffers for the meta key */
+
+ if(!c->inkey)
+ c->inkey = xmalloc(len);
+
+ if(!c->inctx)
+ c->inctx = xmalloc(sizeof(*c->inctx));
+
+ /* Convert the challenge from hexadecimal back to binary */
+
+ hex2bin(buffer,buffer,len);
+
+ /* Decrypt the meta key */
+
+ if(RSA_private_decrypt(len, buffer, c->inkey, myself->connection->rsa_key, RSA_NO_PADDING) != len) /* See challenge() */
+ {
+ syslog(LOG_ERR, _("Error during encryption of meta key for %s (%s)"), c->name, c->hostname);
+ return -1;
+ }
+
+ if(debug_lvl >= DEBUG_SCARY_THINGS)
+ {
+ bin2hex(c->inkey, buffer, len);
+ buffer[len*2] = '\0';
+ syslog(LOG_DEBUG, _("Received random meta key (unencrypted): %s"), buffer);
+ }
+
+ /* All incoming requests will now be encrypted. */
+
+ EVP_DecryptInit(c->inctx, EVP_bf_cfb(),
+ c->inkey + len - EVP_bf_cfb()->key_len,
+ c->inkey + len - EVP_bf_cfb()->key_len - EVP_bf_cfb()->iv_len);
+
+ c->status.decryptin = 1;
+
+ c->allow_request = CHALLENGE;
+cp
+ return send_challenge(c);
+}
+
+int send_challenge(connection_t *c)
+{
+ char *buffer;
+ int len, x;
+cp
+ /* CHECKME: what is most reasonable value for len? */
+
+ len = RSA_size(c->rsa_key);
+
+ /* Allocate buffers for the challenge */
+
+ buffer = xmalloc(len*2+1);
+
+ if(c->hischallenge)
+ free(c->hischallenge);
+
+ c->hischallenge = xmalloc(len);
+cp
+ /* Copy random data to the buffer */
+
+ RAND_bytes(c->hischallenge, len);
+
+cp
+ /* Convert to hex */
+
+ bin2hex(c->hischallenge, buffer, len);
+ buffer[len*2] = '\0';
+
+cp
+ /* Send the challenge */
+
+ x = send_request(c, "%d %s", CHALLENGE, buffer);
+ free(buffer);
+cp
+ return x;
+}
+
+int challenge_h(connection_t *c)
+{
+ char buffer[MAX_STRING_SIZE];
+ int len;
+cp
+ if(sscanf(c->buffer, "%*d "MAX_STRING, buffer) != 1)
+ {
+ syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "CHALLENGE", c->name, c->hostname);
+ return -1;
+ }
+
+ len = RSA_size(myself->connection->rsa_key);
+
+ /* Check if the length of the challenge is all right */
+
+ if(strlen(buffer) != len*2)
+ {
+ syslog(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, "wrong challenge length");
+ return -1;
+ }
+
+ /* Allocate buffers for the challenge */
+
+ if(!c->mychallenge)
+ c->mychallenge = xmalloc(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() */
+cp
+ return send_chal_reply(c);
+}
+
+int send_chal_reply(connection_t *c)
+{
+ char hash[SHA_DIGEST_LENGTH*2+1];
+cp
+ /* Calculate the hash from the challenge we received */
+
+ SHA1(c->mychallenge, RSA_size(myself->connection->rsa_key), hash);
+
+ /* Convert the hash to a hexadecimal formatted string */
+
+ bin2hex(hash,hash,SHA_DIGEST_LENGTH);
+ hash[SHA_DIGEST_LENGTH*2] = '\0';
+
+ /* Send the reply */
+
+cp
+ return send_request(c, "%d %s", CHAL_REPLY, hash);
+}
+
+int chal_reply_h(connection_t *c)
+{
+ char hishash[MAX_STRING_SIZE];
+ char myhash[SHA_DIGEST_LENGTH];
+cp
+ if(sscanf(c->buffer, "%*d "MAX_STRING, hishash) != 1)
+ {
+ syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "CHAL_REPLY", c->name, c->hostname);
+ return -1;
+ }
+
+ /* Check if the length of the hash is all right */
+
+ if(strlen(hishash) != SHA_DIGEST_LENGTH*2)
+ {
+ syslog(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, _("wrong challenge reply length"));
+ return -1;
+ }
+
+ /* Convert the hash to binary format */
+
+ hex2bin(hishash, hishash, SHA_DIGEST_LENGTH);
+
+ /* Calculate the hash from the challenge we sent */
+
+ SHA1(c->hischallenge, RSA_size(c->rsa_key), myhash);
+
+ /* Verify the incoming hash with the calculated hash */
+
+ if(memcmp(hishash, myhash, SHA_DIGEST_LENGTH))
+ {
+ syslog(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, _("wrong challenge reply"));
+ if(debug_lvl >= DEBUG_SCARY_THINGS)
+ {
+ bin2hex(myhash, hishash, SHA_DIGEST_LENGTH);
+ hishash[SHA_DIGEST_LENGTH*2] = '\0';
+ syslog(LOG_DEBUG, _("Expected challenge reply: %s"), hishash);
+ }
+ return -1;
+ }
+
+ /* Identity has now been positively verified.
+ Send an acknowledgement with the rest of the information needed.
+ */
+
+ c->allow_request = ACK;
+cp
+ return send_ack(c);
+}
+
+int send_ack(connection_t *c)
+{
+ /* ACK message contains rest of the information the other end needs
+ to create node_t and edge_t structures. */
+
+ struct timeval now;
+
+ /* Estimate weight */
+
+ gettimeofday(&now, NULL);
+ c->estimated_weight = (now.tv_sec - c->start.tv_sec) * 1000 + (now.tv_usec - c->start.tv_usec) / 1000;
+cp
+ return send_request(c, "%d %hd %d", ACK, myself->port, c->estimated_weight);
+}
+
+int ack_h(connection_t *c)
+{
+ port_t port;
+ int weight;
+ node_t *n;
+ subnet_t *s;
+ edge_t *e;
+ connection_t *other;
+ avl_node_t *node, *node2;
+cp
+ if(sscanf(c->buffer, "%*d %hd %d", &port, &weight) != 2)
+ {
+ syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "ACK", c->name, c->hostname);
+ return -1;
+ }
+
+ /* Check if we already have a node_t for him */
+
+ n = lookup_node(c->name);
+
+ if(!n)
+ {
+ n = new_node();
+ n->name = xstrdup(c->name);
+ n->address = c->address;
+ n->hostname = xstrdup(c->hostname);
+ n->port = port;
+
+ /* FIXME: Also check if no other tinc daemon uses the same IP and port for UDP traffic */
+
+ node_add(n);
+ }
+ else
+ {
+ if(n->connection)
+ {
+ /* Oh dear, we already have a connection to this node. */
+ syslog(LOG_DEBUG, _("Established a second connection with %s (%s), closing old connection"), n->name, n->hostname);
+ terminate_connection(n->connection, 0);
+ }
+
+ /* FIXME: check if information in existing node matches that of the other end of this connection */
+ }
+
+ n->connection = c;
+ c->node = n;
+
+ /* Check some options
+
+ if((cfg = get_config_val(c->config, config_indirectdata)))
+ {
+ if(cfg->data.val == stupid_true)
+ c->options |= OPTION_INDIRECT;
+ }
+
+ if((cfg = get_config_val(c->config, config_tcponly)))
+ {
+ if(cfg->data.val == stupid_true)
+ c->options |= OPTION_TCPONLY;
+ }
+
+ if((myself->options | c->options) & OPTION_INDIRECT)
+ c->via = myself;
+ else
+ c->via = c;
+
+ */
+
+ /* Create an edge_t for this connection */
+
+ c->edge = new_edge();
+
+ c->edge->from = myself;
+ c->edge->to = n;
+ c->edge->weight = (weight + c->estimated_weight) / 2;
+ c->edge->connection = c;
+
+ edge_add(c->edge);
+
+ /* Activate this connection */
+
+ c->allow_request = ALL;
+ c->status.active = 1;
+ c->node->cipher = EVP_bf_cbc();
+ c->node->keylength = c->node->cipher->key_len + c->node->cipher->iv_len;
+
+ if(debug_lvl >= DEBUG_CONNECTIONS)
+ syslog(LOG_NOTICE, _("Connection with %s (%s) activated"), c->name, c->hostname);
+
+cp
+ /* Send him our subnets */
+
+ for(node = myself->subnet_tree->head; node; node = node->next)
+ {
+ s = (subnet_t *)node->data;
+ send_add_subnet(c, s);
+ }
+
+ /* And send him all known nodes and their subnets */
+
+ for(node = node_tree->head; node; node = node->next)
+ {
+ n = (node_t *)node->data;
+
+ if(n == c->node || n == myself)
+ continue;
+
+ send_add_node(c, n);
+
+ for(node2 = c->node->subnet_tree->head; node2; node2 = node2->next)
+ {
+ s = (subnet_t *)node2->data;
+ send_add_subnet(c, s);
+ }
+ }
+
+ /* Send all known edges */
+
+ for(node = edge_tree->head; node; node = node->next)
+ {
+ e = (edge_t *)node->data;
+
+ if(e == c->edge)
+ continue;
+
+ send_add_edge(c, e);
+ }
+
+ /* Notify others of this connection */
+
+ for(node = connection_tree->head; node; node = node->next)
+ {
+ other = (connection_t *)node->data;
+
+ if(other == c)
+ continue;
+
+ send_add_node(other, c->node);
+ send_add_edge(other, c->edge);
+ }
+
+ /* Run MST and SSSP algorithms */
+
+ mst_kruskal();
+ sssp_bfs(0);
+cp
+ return 0;
+}
+
+
+
+/* Address and subnet information exchange */
+
+int send_add_subnet(connection_t *c, subnet_t *subnet)
+{
+ int x;
+ char *netstr;
+cp
+ x = send_request(c, "%d %s %s", ADD_SUBNET,
+ subnet->owner->name, netstr = net2str(subnet));
+ free(netstr);
+cp
+ return x;
+}
+
+int add_subnet_h(connection_t *c)
+{
+ char subnetstr[MAX_STRING_SIZE];
+ char name[MAX_STRING_SIZE];
+ node_t *owner;
+ connection_t *other;
+ subnet_t *s;
+ avl_node_t *node;
+cp
+ if(sscanf(c->buffer, "%*d "MAX_STRING" "MAX_STRING, name, subnetstr) != 2)
+ {
+ syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "ADD_SUBNET", c->name, c->hostname);
+ return -1;
+ }
+
+ /* Check if owner name is a valid */
+
+ if(check_id(name))
+ {
+ syslog(LOG_ERR, _("Got bad %s from %s (%s): %s"), "ADD_SUBNET", c->name, c->hostname, _("invalid name"));
+ return -1;
+ }
+
+ /* Check if subnet string is valid */
+
+ if(!(s = str2net(subnetstr)))
+ {
+ syslog(LOG_ERR, _("Got bad %s from %s (%s): %s"), "ADD_SUBNET", c->name, c->hostname, _("invalid subnet string"));
+ return -1;
+ }
+
+ /* Check if the owner of the new subnet is in the connection list */
+
+ if(!(owner = lookup_node(name)))
+ {
+ syslog(LOG_ERR, _("Got ADD_SUBNET from %s (%s) for %s which is not in our connection list"),
+ name, c->name, c->hostname);
+ return -1;
+ }
+
+ /* If everything is correct, add the subnet to the list of the owner */
+
+ subnet_add(owner, s);
+
+ /* Tell the rest */
+
+ for(node = connection_tree->head; node; node = node->next)
+ {
+ other = (connection_t *)node->data;
+ if(other->status.active && other != c)
+ send_add_subnet(other, s);
+ }
+cp
+ return 0;
+}
+
+int send_del_subnet(connection_t *c, subnet_t *s)
+{
+ int x;
+ char *netstr;
+cp
+ x = send_request(c, "%d %s %s", DEL_SUBNET, s->owner->name, netstr = net2str(s));
+ free(netstr);
+cp
+ return x;
+}
+
+int del_subnet_h(connection_t *c)
+{
+ char subnetstr[MAX_STRING_SIZE];
+ char name[MAX_STRING_SIZE];
+ node_t *owner;
+ connection_t *other;
+ subnet_t *s, *find;
+ avl_node_t *node;
+cp
+ if(sscanf(c->buffer, "%*d "MAX_STRING" "MAX_STRING, name, subnetstr) != 3)
+ {
+ syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "DEL_SUBNET", c->name, c->hostname);
+ return -1;
+ }
+
+ /* Check if owner name is a valid */
+
+ if(check_id(name))
+ {
+ syslog(LOG_ERR, _("Got bad %s from %s (%s): %s"), "DEL_SUBNET", c->name, c->hostname, _("invalid name"));
+ return -1;
+ }
+
+ /* Check if subnet string is valid */
+
+ if(!(s = str2net(subnetstr)))
+ {
+ syslog(LOG_ERR, _("Got bad %s from %s (%s): %s"), "DEL_SUBNET", c->name, c->hostname, _("invalid subnet string"));
+ return -1;
+ }
+
+ /* Check if the owner of the new subnet is in the connection list */
+
+ if(!(owner = lookup_node(name)))
+ {
+ syslog(LOG_ERR, _("Got %s from %s (%s) for %s which is not in our connection list"),
+ "DEL_SUBNET", c->name, c->hostname, name);
+ return -1;
+ }
+
+ /* If everything is correct, delete the subnet from the list of the owner */
+
+ find = lookup_subnet(owner, s);
+
+ if(!find)
+ {
+ syslog(LOG_ERR, _("Got %s from %s (%s) for %s which does not appear in his subnet tree"),
+ "DEL_SUBNET", c->name, c->hostname, name);
+ return -1;
+ }
+
+ subnet_del(owner, s);
+
+ /* Tell the rest */
+
+ for(node = connection_tree->head; node; node = node->next)
+ {
+ other = (connection_t *)node->data;
+ if(other->status.active && other != c)
+ send_del_subnet(other, s);
+ }
+cp
+ return 0;
+}
+
+/* New and closed connections notification */
+
+int send_add_node(connection_t *c, node_t *n)
+{
+cp
+ return send_request(c, "%d %s %lx:%d", ADD_NODE,
+ n->name, n->address, n->port);
+}
+
+int add_node_h(connection_t *c)