Daemon messages processing

Makefile.am

@@ -8,6 +8,7 @@ src_coincerd_SOURCES = \
 	src/crypto.c src/crypto.h \
 	src/daemon_events.c src/daemon_events.h \
 	src/daemon_messages.c src/daemon_messages.h \
+	src/daemon_messages_processor.c src/daemon_messages_processor.h \
 	src/global_state.c src/global_state.h \
 	src/hosts.c src/hosts.h \
 	src/json_parser.c src/json_parser.h \

src/daemon_messages_processor.c

+/*
+ *  Coincer
+ *  Copyright (C) 2017-2018  Coincer Developers
+ *
+ *  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
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <netinet/in.h>
+#include <sodium.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#include "crypto.h"
+#include "daemon_messages.h"
+#include "daemon_messages_processor.h"
+#include "global_state.h"
+#include "hosts.h"
+#include "json_parser.h"
+#include "log.h"
+#include "neighbours.h"
+#include "routing.h"
+
+/** The minimum time in seconds that has to pass between the announcements of
+ *  presence of one identity. */
+#define ADV_GAP_TIME	10
+
+static enum process_message_result process_message(
+						const message_t	*message,
+						neighbour_t	*sender,
+						global_state_t	*global_state);
+
+static int process_p2p_bye(const message_t	*message,
+			   neighbour_t		*sender,
+			   peer_t		*sender_peer,
+			   global_state_t	*global_state);
+static int process_p2p_hello(const message_t	*message,
+			     neighbour_t	*sender,
+			     linkedlist_t	*neighbours,
+			     unsigned short	port);
+static int process_p2p_peers_adv(const message_t *message,
+				 neighbour_t	 *sender,
+				 linkedlist_t	 *hosts);
+static int process_p2p_peers_sol(neighbour_t	    *sender,
+				 const linkedlist_t *hosts);
+static int process_p2p_ping(neighbour_t *sender);
+static int process_p2p_pong(neighbour_t *sender);
+static int process_p2p_route_adv(const message_t *message,
+				 neighbour_t	 *sender,
+				 peer_t		 *sender_peer,
+				 global_state_t	 *global_state);
+static int process_p2p_route_sol(const message_t *message,
+				 neighbour_t	 *sender,
+				 global_state_t	 *global_state);
+
+/**
+ * Process a JSON message received from its forwarder/sender (our neighbour).
+ *
+ * @param	json_message		The received JSON message.
+ * @param	sender			The message sender/forwarder.
+ * @param	global_state		The global state.
+ *
+ * @return	PMR_DONE		The received message was successfully
+ *					processed.
+ * @return	PMR_ERR_INTEGRITY	Someone tampered with the message.
+ * @return	PMR_ERR_INTERNAL	Internal processing error.
+ * @return	PMR_ERR_PARSING		Parsing failure.
+ * @return	PMR_ERR_SEMANTIC	Semantic error.
+ * @return	PMR_ERR_VERSION		The message is of different
+ *					protocol version.
+ */
+enum process_message_result process_encoded_message(
+						const char	*json_message,
+						neighbour_t	*sender,
+						global_state_t	*global_state)
+{
+	char				*json_message_body;
+	message_t			message;
+	enum process_message_result	ret;
+
+	/* decode JSON message; if parsing JSON message into message_t failed */
+	if (decode_message(json_message, &message)) {
+		log_debug("process_encoded_message - decoding a received "
+			  "message has failed");
+		return PMR_ERR_PARSING;
+	}
+
+	if (message.version != PROTOCOL_VERSION) {
+		message_delete(&message);
+		return PMR_ERR_VERSION;
+	}
+
+	/* integrity verification part; get message body in JSON format */
+	if (encode_message_body(&message.body, &json_message_body)) {
+		log_error("Encoding what we've just decoded has failed");
+		message_delete(&message);
+		return PMR_ERR_INTERNAL;
+	}
+	/* if the message integrity is violated */
+	if (verify_signature(json_message_body, message.from, message.sig)) {
+		log_warn("Someone tampered with a received message");
+		free(json_message_body);
+		message_delete(&message);
+		return PMR_ERR_INTEGRITY;
+	}
+	/* integrity verification done */
+	free(json_message_body);
+
+	/* process the message */
+	ret = process_message(&message, sender, global_state);
+
+	message_delete(&message);
+	return ret;
+}
+
+/**
+ * Process a message received from its forwarder/sender (our neighbour).
+ *
+ * @param	message			The received message.
+ * @param	sender			The message sender/forwarder.
+ * @param	global_state		The global state.
+ *
+ * @return	PMR_DONE		The received message was successfully
+ *					processed.
+ * @return	PMR_ERR_INTERNAL	Internal processing error.
+ * @return	PMR_ERR_SEMANTIC	Semantic error.
+ */
+static enum process_message_result process_message(
+						const message_t	*message,
+						neighbour_t	*sender,
+						global_state_t	*global_state)
+{
+	int			cmp_val;
+	linkedlist_t		*hosts;
+	linkedlist_t		*identities;
+	identity_t		*identity;
+	const message_body_t	*msg_body;
+	const linkedlist_t	*msg_traces;
+	enum message_type	msg_type;
+	linkedlist_t		*neighbours;
+	uint64_t		nonce_value;
+	linkedlist_t		*peers;
+	int			res;
+	linkedlist_t		*routing_table;
+	peer_t			*sender_peer;
+
+	msg_body    = &message->body;
+	msg_type    = msg_body->type;
+	nonce_value = msg_body->nonce;
+
+	hosts	      = &global_state->hosts;
+	identities    = &global_state->identities;
+	msg_traces    = &global_state->message_traces;
+	neighbours    = &global_state->neighbours;
+	peers	      = &global_state->peers;
+	routing_table = &global_state->routing_table;
+
+	/* if we haven't yet received p2p.hello from the neighbour who's
+	 * sent/forwarded the received message */
+	if (!(sender->flags & NEIGHBOUR_ACTIVE)) {
+		/* and the message is not p2p.hello */
+		if (msg_type != P2P_HELLO) {
+			log_debug("process_message - received non-hello msg "
+				  "before p2p.hello");
+			return PMR_ERR_SEMANTIC;
+		}
+		res = process_p2p_hello(message,
+					sender,
+					neighbours,
+					global_state->port);
+		if (!res) {
+			nonce_store(&sender->pseudonym.nonces, nonce_value);
+			return PMR_DONE;
+		}
+
+		return PMR_ERR_INTERNAL;
+	}
+
+	/* if we've received a message that we've created */
+	if (identity_find(identities, message->from)) {
+		/* and if it is a p2p message */
+		if (!identifier_empty(msg_body->to)) {
+			routing_loop_remove(routing_table,
+					    neighbours,
+					    identities,
+					    msg_body->to);
+		}
+		return PMR_DONE;
+	}
+
+	/* let's get peer representations of the sender and appropriate ours */
+
+	cmp_val	    = 0;
+	sender_peer = NULL;
+	/* all bytes of 'to' are set to 0x0 => we are one of the recipients */
+	if (identifier_empty(msg_body->to)) {
+		/* 'from' different from the neighbour's pseudonym =>
+		 *  the message should be a broadcast (we will check later) */
+		if (memcmp(message->from,
+			   sender->pseudonym.identifier,
+			   crypto_box_PUBLICKEYBYTES)) {
+			/* process the broadcast with the true identity */
+			identity = global_state->true_identity;
+		/* otherwise it is a n2n message */
+		} else {
+			identity = &sender->my_pseudonym;
+			sender_peer = &sender->pseudonym;
+
+			/* for later parity check */
+			cmp_val = memcmp(message->from,
+					 identity->keypair.public_key,
+					 crypto_box_PUBLICKEYBYTES);
+		}
+	/* the message is of type p2p */
+	} else {
+		/* identity will be NULL if the message is not meant for us */
+		identity = identity_find(identities, msg_body->to);
+		/* for later parity check */
+		cmp_val = memcmp(message->from,
+				 msg_body->to,
+				 crypto_box_PUBLICKEYBYTES);
+	}
+
+	/* nonce parity check; the message must have:
+	 * sender ID > our ID => odd nonce; sender ID < our ID => even nonce */
+	if ((cmp_val > 0 && nonce_value % 2 == 0) ||
+	    (cmp_val < 0 && nonce_value % 2 == 1)) {
+		log_debug("process_mesage - wrong nonce parity");
+		return PMR_ERR_SEMANTIC;
+	}
+
+	/* if the message is not n2n */
+	if (!sender_peer) {
+		/* from what peer is this message? */
+		sender_peer = peer_find(peers, message->from);
+	}
+	/* if we don't know this peer yet */
+	if (!sender_peer) {
+		sender_peer = peer_store(peers, message->from);
+		/* storing the new peer has failed */
+		if (!sender_peer) {
+			return PMR_ERR_INTERNAL;
+		}
+	} else {
+		if (msg_type == P2P_ROUTE_ADV) {
+			/* if it's an old announcement of presence, skip it */
+			if (nonce_value < sender_peer->presence_nonce.value) {
+				return PMR_DONE;
+			}
+		} else {
+			/* have we already processed this message? */
+			if (nonces_find(&sender_peer->nonces, nonce_value)) {
+				/* if broadcast or n2n msg */
+				if (identifier_empty(msg_body->to) ||
+				    identity == &sender->my_pseudonym) {
+					return PMR_DONE;
+				}
+				/* check if there's a routing loop */
+				if (routing_loop_detect(msg_traces,
+							sender,
+							nonce_value)) {
+					routing_loop_remove(routing_table,
+							    neighbours,
+							    identities,
+							    msg_body->to);
+				}
+				return PMR_DONE;
+			}
+			/* if the message smells like replay attack */
+			if (!linkedlist_empty(&sender_peer->nonces) &&
+			     nonce_value <
+			    (nonces_get_first(&sender_peer->nonces))->value) {
+				log_warn("Potential replay attack detected");
+				return PMR_ERR_SEMANTIC;
+			}
+		}
+	}
+
+	/* no corresponding identity to process the message => the message is
+	 * not meant for us */
+	if (!identity) {
+		/* if forwarding succeeded */
+		if (!message_forward(message, sender, global_state)) {
+			/* store message's nonce */
+			nonce_store(&sender_peer->nonces, nonce_value);
+		}
+		return PMR_DONE;
+	} else if (identity->flags & IDENTITY_TMP) {
+		/* no one is supposed to send a message to this identity */
+		return PMR_ERR_SEMANTIC;
+	}
+
+	/* the message is meant for us; process it */
+
+	switch (msg_type) {
+		case P2P_BYE:
+			res = process_p2p_bye(message,
+					      sender,
+					      sender_peer,
+					      global_state);
+			break;
+		case P2P_HELLO:
+			res = process_p2p_hello(message,
+						sender,
+						neighbours,
+						global_state->port);
+			break;
+		case P2P_PEERS_ADV:
+			/* if the message was not sent by the same peer
+			 * pseudonym of the sender as their p2p.hello */
+			if (&sender->pseudonym != sender_peer) {
+				log_debug("process_message - incorrect sender");
+				/* since the message was sent by other ID than
+				 * neighbour's pseudonym, we've treated it as a
+				 * new peer; that's unwanted for n2n messages */
+				peer_delete(sender_peer);
+				return PMR_ERR_SEMANTIC;
+			}
+			res = process_p2p_peers_adv(message, sender, hosts);
+			break;
+		case P2P_PEERS_SOL:
+			res = process_p2p_peers_sol(sender, hosts);
+			break;
+		case P2P_PING:
+			res = process_p2p_ping(sender);
+			break;
+		case P2P_PONG:
+			if (&sender->pseudonym != sender_peer) {
+				log_debug("process_message - incorrect sender");
+				peer_delete(sender_peer);
+				return PMR_ERR_SEMANTIC;
+			}
+			res = process_p2p_pong(sender);
+			break;
+		case P2P_ROUTE_ADV:
+			res = process_p2p_route_adv(message,
+						    sender,
+						    sender_peer,
+						    global_state);
+			break;
+		case P2P_ROUTE_SOL:
+			res = process_p2p_route_sol(message,
+						    sender,
+						    global_state);
+			break;
+		default:
+			log_debug("process_message - unknown message type");
+			return PMR_ERR_SEMANTIC;
+	}
+
+	/* if the message processing has failed */
+	if (res) {
+		return PMR_ERR_INTERNAL;
+	}
+
+	/* sucessfully processed; store message's nonce */
+	if (msg_type == P2P_ROUTE_ADV) {
+		presence_nonce_store(sender_peer, nonce_value);
+	} else if (msg_type != P2P_BYE) {
+		nonce_store(&sender_peer->nonces, nonce_value);
+	}
+
+	sender->failed_pings = 0;
+
+	return PMR_DONE;
+}
+
+/**
+ * Process p2p.bye.
+ *
+ * @param	message		Process this message.
+ * @param	sender		We've received the message from this neighbour.
+ * @param	sender_peer	Sender's peer representation.
+ * @param	global_state	The global state.
+ *
+ * @return	0		Successfully processed.
+ */
+static int process_p2p_bye(const message_t	*message,
+			   neighbour_t		*sender,
+			   peer_t		*sender_peer,
+			   global_state_t	*global_state)
+{
+	route_delete(&global_state->routing_table, message->from);
+	peer_delete(sender_peer);
+
+	message_forward(message, sender, global_state);
+
+	return 0;
+}
+
+/**
+ * Process p2p.hello.
+ *
+ * @param	message		Process this message.
+ * @param	sender		We've received the message from this neighbour.
+ * @param	neighbours	Our neighbours.
+ * @param	port		Our listening port.
+ *
+ * @return	0		Successfully processed.
+ * @return	1		Failure.
+ */
+static int process_p2p_hello(const message_t	*message,
+			     neighbour_t	*sender,
+			     linkedlist_t	*neighbours,
+			     unsigned short	port)
+{
+	p2p_hello_t *hello;
+	neighbour_t *neighbour;
+
+	/* don't take hello from already active neighbour */
+	if (sender->flags & NEIGHBOUR_ACTIVE) {
+		return 1;
+	}
+
+	/* check self-neighbouring; if we have a neighbour with 'my_pseudonym'
+	 * the same as the received message's sender ID, then we've
+	 * detected self-neighbouring; delete the mentioned neighbour,
+	 * and also delete the message sender (our neighbour representation of
+	 * the sending counterparty)
+	 */
+	if ((neighbour = find_neighbour(neighbours,
+				message->from,
+				compare_neighbour_my_pseudonyms))) {
+		linkedlist_delete_safely(neighbour->node, clear_neighbour);
+		linkedlist_delete_safely(sender->node, clear_neighbour);
+		return 1;
+	}
+
+	hello = (p2p_hello_t *) message->body.data;
+
+	sender->client = (char *) malloc((strlen(hello->client) + 1) *
+					 sizeof(char));
+	if (!sender->client) {
+		log_error("Processing p2p.hello");
+		return 1;
+	}
+	strcpy(sender->client, hello->client);
+
+	/* if the new neighbour is not one of the default hosts */
+	if (sender->host) {
+		sender->host->port = hello->port;
+	}
+
+	memcpy(sender->pseudonym.identifier,
+	       message->from,
+	       crypto_box_PUBLICKEYBYTES);
+
+	set_neighbour_flags(sender, NEIGHBOUR_ACTIVE);
+
+	return send_p2p_hello(sender, port);
+}
+
+/**
+ * Process p2p.peers.adv.
+ *
+ * @param	message		Process this message.
+ * @param	sender		We've received the message from this neighbour.
+ * @param	hosts		Our known hosts.
+ *
+ * @return	0		Successfully processed.
+ * @return	1		Failure.
+ */
+static int process_p2p_peers_adv(const message_t *message,
+				 neighbour_t	 *sender,
+				 linkedlist_t	 *hosts)
+{
+	struct in6_addr	addr;
+	char		addr_str[INET6_ADDRSTRLEN];
+	size_t		n;
+	p2p_peers_adv_t	*peers_adv;
+	unsigned short	port;
+	char		*pos;
+	char		tuple[55]; /* string address	 = 45 chars,
+				    * string port	 = 5  chars,
+				    * ',' + 3x' ' + '\0' = 5  chars,
+				    * total		 = 55 chars
+				    */
+
+	/* if we haven't asked this neighbour for addresses */
+	if (!(sender->flags & NEIGHBOUR_ADDRS_REQ)) {
+		log_debug("process_p2p_peers_adv - unwanted addrs arrived");
+		return 1;
+	}
+	unset_neighbour_flags(sender, NEIGHBOUR_ADDRS_REQ);
+
+	peers_adv = (p2p_peers_adv_t *) message->body.data;
+
+	/* if the list doesn't have enough chars to be even empty ("[  ]",
+	 * which is 4 chars) */
+	if (strlen(peers_adv->addresses) < 4) {
+		log_debug("process_p2p_peers_adv - wrong addrs format");
+		return 1;
+	}
+
+	/* set initial pointer position; skip the outer list '[' */
+	pos = peers_adv->addresses + 1;
+	/* get position of the first '[' */
+	pos = strchr(pos, '[');
+
+	/* while there is a tuple to be processed */
+	while (pos) {
+		/* get the number of chars between the current '[' and the next
+		 * ']', both boundary chars excluding */
+		n = strcspn(++pos, "]");
+
+		/* the tuple can not have more than 54 chars (plus '\0') */
+		if (n > 54) {
+			log_debug("process_p2p_peers_adv - wrong addrs format");
+			return 1;
+		}
+
+		/* copy the chars between '[' and ']', both boundary
+		 * chars excluding */
+		strncpy(tuple, pos, n);
+		tuple[n] = '\0';
+
+		/* get string addr and numerical port from the tuple */
+		if (sscanf(tuple, " %[^,], %hu ", addr_str, &port) != 2) {
+			log_debug("process_p2p_peers_adv - wrong addrs format");
+			return 1;
+		}
+
+		/* if conversion of addr_str into addr succeeded */
+		if (inet_pton(AF_INET6, addr_str, &addr) == 1) {
+			save_host(hosts, &addr, port, HOST_AVAILABLE);
+		}
+
+		/* go to next tuple */
+		pos = strchr(pos, '[');
+	}
+
+	return 0;
+}
+
+/**
+ * Process p2p.peers.sol.
+ *
+ * @param	sender		We've received the message from this neighbour.
+ * @param	hosts		Hosts known to us.
+ *
+ * @return	0		Successfully processed.
+ * @return	1		Failure.
+ */
+static int process_p2p_peers_sol(neighbour_t *sender, const linkedlist_t *hosts)
+{
+	return send_p2p_peers_adv(sender, hosts);
+}
+
+/**
+ * Process p2p.ping.
+ *
+ * @param	sender		We've received the message from this neighbour.
+ *
+ * @return	0		Successfully processed.
+ * @return	1		Failure.
+ */
+static int process_p2p_ping(neighbour_t *sender)
+{
+	return send_p2p_pong(sender);
+}
+
+/**
+ * Process p2p.pong.
+ *
+ * @param	sender		We've received the message from this neighbour.
+ *
+ * @return	0		Successfully processed.
+ */
+static int process_p2p_pong(neighbour_t *sender)
+{
+	sender->failed_pings = 0;
+
+	return 0;
+}
+
+/**
+ * Process p2p.route.adv.
+ *
+ * @param	message		Process this message.
+ * @param	sender		We've received the message from this neighbour.
+ * @param	sender_peer	Sender's peer representation.
+ * @param	global_state	The global state.
+ *
+ * @return	0		Successfully processed.
+ * @return	1		Failure.
+ */
+static int process_p2p_route_adv(const message_t *message,
+				 neighbour_t	 *sender,
+				 peer_t		 *sender_peer,
+				 global_state_t	 *global_state)
+{
+	route_t		*route;
+	linkedlist_t	*routing_table;
+
+	routing_table = &global_state->routing_table;
+
+	route = route_find(routing_table, message->from);
+	if (!route) {
+		if (!(route = route_add(routing_table, sender_peer, sender))) {
+			log_error("Adding a new route");
+			return 1;
+		}
+	}