From 872e0dfa86417e89022f84ac78b2d90236cb97d4 Mon Sep 17 00:00:00 2001
From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Mon, 16 Apr 2012 07:29:55 +0200
Subject: Lots of fixes and improvements on the resolver code

---
 src/config.c                  | 18 ++++++++--
 src/fastd.c                   | 80 ++++++++++++++++++++++++++-----------------
 src/fastd.h                   |  8 +++--
 src/peer.c                    | 25 +++++++++++---
 src/peer.h                    |  8 +++++
 src/protocol_ec25519_fhmqvc.c | 29 +++++++++++-----
 src/resolve.c                 | 23 ++++++-------
 7 files changed, 127 insertions(+), 64 deletions(-)

diff --git a/src/config.c b/src/config.c
index e7c8640..d581ccf 100644
--- a/src/config.c
+++ b/src/config.c
@@ -292,20 +292,32 @@ static void count_peers(fastd_context *ctx, fastd_config *conf) {
 	conf->n_floating = 0;
 	conf->n_v4 = 0;
 	conf->n_v6 = 0;
+	conf->n_dynamic = 0;
+	conf->n_dynamic_v4 = 0;
+	conf->n_dynamic_v6 = 0;
 
 	fastd_peer_config *peer;
 	for (peer = conf->peers; peer; peer = peer->next) {
 		switch (peer->address.sa.sa_family) {
 		case AF_UNSPEC:
-			conf->n_floating++;
+			if (peer->hostname)
+				conf->n_dynamic++;
+			else
+				conf->n_floating++;
 			break;
 
 		case AF_INET:
-			conf->n_v4++;
+			if (peer->hostname)
+				conf->n_dynamic_v4++;
+			else
+				conf->n_v4++;
 			break;
 
 		case AF_INET6:
-			conf->n_v6++;
+			if (peer->hostname)
+				conf->n_dynamic_v6++;
+			else
+				conf->n_v6++;
 			break;
 
 		default:
diff --git a/src/fastd.c b/src/fastd.c
index 59e5c54..ee7f03a 100644
--- a/src/fastd.c
+++ b/src/fastd.c
@@ -55,6 +55,9 @@ static void on_terminate(int signo) {
 }
 
 static void on_sigusr1(int signo, siginfo_t *siginfo, void *context) {
+	if (siginfo->si_code != SI_QUEUE || !siginfo->si_value.sival_ptr)
+		return;
+
 	fastd_resolve_return *ret = siginfo->si_value.sival_ptr;
 
 	ret->next = ret->ctx->resolve_returns;
@@ -133,10 +136,10 @@ static void init_sockets(fastd_context *ctx) {
 	struct sockaddr_in6 addr_in6 = ctx->conf->bind_addr_in6;
 
 	if (addr_in.sin_family == AF_UNSPEC && addr_in6.sin6_family == AF_UNSPEC) {
-		if (ctx->conf->n_floating || ctx->conf->peer_dirs || ctx->conf->n_v4)
+		if (ctx->conf->peer_dirs || ctx->conf->n_floating || ctx->conf->n_v4 || ctx->conf->n_dynamic || ctx->conf->n_dynamic_v4)
 			addr_in.sin_family = AF_INET;
 
-		if (ctx->conf->n_floating || ctx->conf->peer_dirs || ctx->conf->n_v6)
+		if (ctx->conf->peer_dirs || ctx->conf->n_floating || ctx->conf->n_v6 || ctx->conf->n_dynamic || ctx->conf->n_dynamic_v6)
 			addr_in6.sin6_family = AF_INET6;
 	}
 
@@ -362,13 +365,15 @@ static void delete_peers(fastd_context *ctx) {
 	}
 }
 
-static void update_time(fastd_context *ctx) {
+static inline void update_time(fastd_context *ctx) {
 	clock_gettime(CLOCK_MONOTONIC, &ctx->now);
 }
 
-static void send_handshake(fastd_context *ctx, fastd_peer *peer) {
-	pr_debug(ctx, "sending handshake to %P...", peer);
-	ctx->conf->protocol->handshake_init(ctx, peer);
+static inline void send_handshake(fastd_context *ctx, fastd_peer *peer) {
+	if (peer->address.sa.sa_family != AF_UNSPEC) {
+		pr_debug(ctx, "sending handshake to %P...", peer);
+		ctx->conf->protocol->handshake_init(ctx, peer);
+	}
 
 	fastd_task_schedule_handshake(ctx, peer, fastd_rand(ctx, 17500, 22500));
 }
@@ -379,7 +384,7 @@ static void handle_tasks(fastd_context *ctx) {
 		switch (task->type) {
 		case TASK_HANDSHAKE:
 			if (task->peer->state == STATE_RESOLVE)
-				fastd_resolve_peer_handshake(ctx, task->peer);
+				fastd_resolve_peer(ctx, task->peer->config);
 			else
 				send_handshake(ctx, task->peer);
 			break;
@@ -516,7 +521,9 @@ static void handle_socket(fastd_context *ctx, int sockfd) {
 			fastd_buffer_free(buffer);
 		}
 	}
-	else if(ctx->conf->n_floating) {
+	else if(ctx->conf->n_floating || ctx->conf->n_dynamic ||
+		(recvaddr.sa.sa_family == AF_INET && ctx->conf->n_dynamic_v4) ||
+		(recvaddr.sa.sa_family == AF_INET6 && ctx->conf->n_dynamic_v6)) {
 		switch (packet_type) {
 		case PACKET_DATA:
 			peer = fastd_peer_add_temp(ctx, (fastd_peer_address*)&recvaddr);
@@ -570,25 +577,51 @@ static void handle_input(fastd_context *ctx) {
 		handle_socket(ctx, ctx->sock6fd);
 }
 
+static void cleanup_peers(fastd_context *ctx) {
+	fastd_peer *peer, *next;
+
+	for (peer = ctx->peers; peer; peer = next) {
+		next = peer->next;
+
+		if (fastd_peer_is_temporary(peer)) {
+			if (timespec_diff(&ctx->now, &peer->seen) > ctx->conf->peer_stale_time_temp*1000)
+				fastd_peer_reset(ctx, peer);
+		}
+		else if (fastd_peer_is_established(peer)) {
+			if (timespec_diff(&ctx->now, &peer->seen) > ctx->conf->peer_stale_time*1000)
+				fastd_peer_reset(ctx, peer);
+		}
+	}
+}
+
+static void cleanup_peer_with_address(fastd_context *ctx, const fastd_peer_address *addr) {
+	fastd_peer *peer;
+	for (peer = ctx->peers; peer; peer = peer->next) {
+		if (fastd_peer_is_temporary(peer) && fastd_peer_addr_equal(&peer->address, addr)) {
+			fastd_peer_reset(ctx, peer);
+			return;
+		}
+	}
+}
+
 static void handle_resolv_returns(fastd_context *ctx) {
 	while (ctx->resolve_returns) {
 		fastd_peer *peer;
 		for (peer = ctx->peers; peer; peer = peer->next) {
-			if (peer->state != STATE_RESOLVE)
+			if (!peer->config)
 				continue;
 
 			if (!strequal(peer->config->hostname, ctx->resolve_returns->hostname))
 				continue;
 
-			if (peer->config->address.sa.sa_family != AF_UNSPEC &&
-			    peer->config->address.sa.sa_family != ctx->resolve_returns->addr.sa.sa_family)
-				continue;
-
-			if (peer->config->address.in.sin_port != htons(ctx->resolve_returns->port))
+			if (!fastd_peer_config_matches_dynamic(peer->config, &ctx->resolve_returns->constraints))
 				continue;
 
+			cleanup_peer_with_address(ctx, &ctx->resolve_returns->addr);
 			peer->address = ctx->resolve_returns->addr;
-			send_handshake(ctx, peer);
+
+			if (peer->state == STATE_RESOLVE)
+				send_handshake(ctx, peer);
 			break;
 		}
 
@@ -599,23 +632,6 @@ static void handle_resolv_returns(fastd_context *ctx) {
 	}
 }
 
-static void cleanup_peers(fastd_context *ctx) {
-	fastd_peer *peer, *next;
-
-	for (peer = ctx->peers; peer; peer = next) {
-		next = peer->next;
-
-		if (fastd_peer_is_temporary(peer)) {
-			if (timespec_diff(&ctx->now, &peer->seen) > ctx->conf->peer_stale_time_temp*1000)
-				fastd_peer_reset(ctx, peer);
-		}
-		else if (fastd_peer_is_established(peer)) {
-			if (timespec_diff(&ctx->now, &peer->seen) > ctx->conf->peer_stale_time*1000)
-				fastd_peer_reset(ctx, peer);
-		}
-	}
-}
-
 static void maintenance(fastd_context *ctx) {
 	cleanup_peers(ctx);
 
diff --git a/src/fastd.h b/src/fastd.h
index c778b19..1fa4d17 100644
--- a/src/fastd.h
+++ b/src/fastd.h
@@ -103,8 +103,7 @@ struct _fastd_resolve_return {
 	fastd_context *ctx;
 
 	char *hostname;
-	sa_family_t af;
-	uint16_t port;
+	fastd_peer_address constraints;
 
 	fastd_peer_address addr;
 };
@@ -139,6 +138,9 @@ struct _fastd_config {
 	unsigned n_floating;
 	unsigned n_v4;
 	unsigned n_v6;
+	unsigned n_dynamic;
+	unsigned n_dynamic_v4;
+	unsigned n_dynamic_v6;
 
 	fastd_protocol_config *protocol_config;
 
@@ -188,7 +190,7 @@ void fastd_send(fastd_context *ctx, fastd_peer *peer, fastd_buffer buffer);
 void fastd_send_handshake(fastd_context *ctx, fastd_peer *peer, fastd_buffer buffer);
 void fastd_handle_receive(fastd_context *ctx, fastd_peer *peer, fastd_buffer buffer);
 
-void fastd_resolve_peer_handshake(fastd_context *ctx, fastd_peer *peer);
+void fastd_resolve_peer(fastd_context *ctx, const fastd_peer_config *peer);
 
 void fastd_printf(const fastd_context *ctx, const char *format, ...);
 
diff --git a/src/peer.c b/src/peer.c
index 1a6ddd9..1ad4c7f 100644
--- a/src/peer.c
+++ b/src/peer.c
@@ -251,7 +251,7 @@ void fastd_peer_config_purge(fastd_context *ctx, fastd_peer_config *conf) {
 	fastd_peer_config_free(conf);
 }
 
-static bool fastd_peer_addr_equal(const fastd_peer_address *addr1, const fastd_peer_address *addr2) {
+bool fastd_peer_addr_equal(const fastd_peer_address *addr1, const fastd_peer_address *addr2) {
 	if (addr1->sa.sa_family != addr2->sa.sa_family)
 		return false;
 
@@ -330,9 +330,6 @@ fastd_peer* fastd_peer_add(fastd_context *ctx, fastd_peer_config *peer_conf) {
 fastd_peer* fastd_peer_add_temp(fastd_context *ctx, const fastd_peer_address *address) {
 	fastd_peer *peer = add_peer(ctx);
 
-	if (!ctx->conf->n_floating)
-		exit_bug(ctx, "tried to add a temporary peer with no floating remotes defined");
-
 	peer->config = NULL;
 	peer->address = *address;
 	peer->state = STATE_TEMP;
@@ -409,6 +406,26 @@ const fastd_eth_addr* fastd_get_dest_address(const fastd_context *ctx, fastd_buf
 	}
 }
 
+bool fastd_peer_config_matches_dynamic(const fastd_peer_config *config, const fastd_peer_address *addr) {
+	if (!config->hostname)
+		return false;
+
+	if (config->address.sa.sa_family != AF_UNSPEC &&
+	    config->address.sa.sa_family != addr->sa.sa_family)
+		return false;
+
+	if (addr->sa.sa_family == AF_INET6) {
+		if (config->address.in.sin_port != addr->in6.sin6_port)
+			return false;
+	}
+	else {
+		if (config->address.in.sin_port != addr->in.sin_port)
+			return false;
+	}
+
+	return true;
+}
+
 static inline int fastd_eth_addr_cmp(const fastd_eth_addr *addr1, const fastd_eth_addr *addr2) {
 	return memcmp(addr1->data, addr2->data, ETH_ALEN);
 }
diff --git a/src/peer.h b/src/peer.h
index 7521799..f8b0f84 100644
--- a/src/peer.h
+++ b/src/peer.h
@@ -67,6 +67,8 @@ struct _fastd_peer_eth_addr {
 };
 
 
+bool fastd_peer_addr_equal(const fastd_peer_address *addr1, const fastd_peer_address *addr2);
+
 fastd_peer_config* fastd_peer_config_new(fastd_context *ctx, fastd_config *conf);
 void fastd_peer_config_free(fastd_peer_config *peer);
 void fastd_peer_config_delete(fastd_context *ctx, fastd_config *conf);
@@ -87,10 +89,16 @@ static inline bool fastd_peer_config_is_floating(const fastd_peer_config *config
 	return (config->hostname == NULL && config->address.sa.sa_family == AF_UNSPEC);
 }
 
+bool fastd_peer_config_matches_dynamic(const fastd_peer_config *config, const fastd_peer_address *addr);
+
 static inline bool fastd_peer_is_floating(const fastd_peer *peer) {
 	return (peer->config && fastd_peer_config_is_floating(peer->config));
 }
 
+static inline bool fastd_peer_is_dynamic(const fastd_peer *peer) {
+	return (peer->config && peer->config->hostname);
+}
+
 static inline bool fastd_peer_is_waiting(const fastd_peer *peer) {
 	return (peer->state == STATE_WAIT);
 }
diff --git a/src/protocol_ec25519_fhmqvc.c b/src/protocol_ec25519_fhmqvc.c
index b4dab07..93fd9c4 100644
--- a/src/protocol_ec25519_fhmqvc.c
+++ b/src/protocol_ec25519_fhmqvc.c
@@ -245,10 +245,6 @@ static void protocol_handshake_init(fastd_context *ctx, fastd_peer *peer) {
 	fastd_send_handshake(ctx, peer, buffer);
 }
 
-static inline bool has_field(const fastd_handshake *handshake, uint8_t type, size_t length) {
-	return (handshake->records[type].length == length);
-}
-
 static void respond_handshake(fastd_context *ctx, fastd_peer *peer, const fastd_handshake *handshake) {
 	pr_debug(ctx, "responding handshake with %P...", peer);
 
@@ -454,20 +450,27 @@ static void handle_finish_handshake(fastd_context *ctx, fastd_peer *peer, const
 		  &peer->protocol_state->accepting_handshake->sigma);
 }
 
-static inline const fastd_peer_config* match_sender_key(fastd_context *ctx, const fastd_peer *peer, const unsigned char key[32]) {
+static inline const fastd_peer_config* match_sender_key(fastd_context *ctx, fastd_peer *peer, const unsigned char key[32]) {
 	if (peer->config) {
 		if (memcmp(peer->config->protocol_config->public_key.p, key, PUBLICKEYBYTES) == 0)
 			return peer->config;
 	}
 
-	if (fastd_peer_is_temporary(peer) || fastd_peer_is_floating(peer)) {
+	if (fastd_peer_is_temporary(peer) || fastd_peer_is_floating(peer) || fastd_peer_is_dynamic(peer)) {
 		fastd_peer_config *config;
 		for (config = ctx->conf->peers; config; config = config->next) {
-			if (!fastd_peer_config_is_floating(config))
+			if (!fastd_peer_config_is_floating(config) && !fastd_peer_config_matches_dynamic(config, &peer->address))
 				continue;
 
-		if (memcmp(config->protocol_config->public_key.p, key, PUBLICKEYBYTES) == 0)
-			return config;
+			if (memcmp(config->protocol_config->public_key.p, key, PUBLICKEYBYTES) == 0) {
+				if (fastd_peer_config_is_floating(config)) {
+					return config;
+				}
+				else { /* matches dynamic */
+					fastd_resolve_peer(ctx, config);
+					return NULL;
+				}
+			}
 		}
 	}
 
@@ -484,6 +487,10 @@ static void kill_handshakes(fastd_context *ctx, fastd_peer *peer) {
 	peer->protocol_state->accepting_handshake = NULL;
 }
 
+static inline bool has_field(const fastd_handshake *handshake, uint8_t type, size_t length) {
+	return (handshake->records[type].length == length);
+}
+
 static void protocol_handshake_handle(fastd_context *ctx, fastd_peer *peer, const fastd_handshake *handshake) {
 	init_peer_state(ctx, peer);
 
@@ -493,6 +500,10 @@ static void protocol_handshake_handle(fastd_context *ctx, fastd_peer *peer, cons
 	}
 
 	const fastd_peer_config *peer_config = match_sender_key(ctx, peer, handshake->records[RECORD_SENDER_KEY].data);
+	if (!peer_config) {
+		pr_debug(ctx, "ignoring handshake from %P (unknown key or unresolved host)", peer);
+		return;
+	}
 
 	if (handshake->type > 1 && !has_field(handshake, RECORD_RECEIPIENT_KEY, PUBLICKEYBYTES)) {
 		pr_debug(ctx, "received handshake reply without receipient key from %P", peer);
diff --git a/src/resolve.c b/src/resolve.c
index 1fbb1bf..6afea91 100644
--- a/src/resolve.c
+++ b/src/resolve.c
@@ -38,12 +38,11 @@ typedef struct _resolv_arg {
 	fastd_context *ctx;
 	pthread_t master_thread;
 	char *hostname;
-	sa_family_t af;
-	uint16_t port;
+	fastd_peer_address constraints;
 } resolv_arg;
 
 
-static void* fastd_resolve_peer_handshake_do(void *varg) {
+static void* resolve_peer(void *varg) {
 	resolv_arg *arg = varg;
 
 	struct addrinfo hints;
@@ -52,10 +51,10 @@ static void* fastd_resolve_peer_handshake_do(void *varg) {
 	bool error = false;
 
 	char portstr[6];
-	snprintf(portstr, 6, "%u", arg->port);
+	snprintf(portstr, 6, "%u", ntohs(arg->constraints.in.sin_port));
 
 	memset(&hints, 0, sizeof(struct addrinfo));
-	hints.ai_family = arg->af;
+	hints.ai_family = arg->constraints.sa.sa_family;
 	hints.ai_socktype = SOCK_DGRAM;
 	hints.ai_protocol = IPPROTO_UDP;
 	hints.ai_flags = AI_NUMERICSERV | AI_ADDRCONFIG;
@@ -79,8 +78,7 @@ static void* fastd_resolve_peer_handshake_do(void *varg) {
 	ret->ctx = arg->ctx;
 
 	ret->hostname = arg->hostname;
-	ret->af = arg->af;
-	ret->port = arg->port;
+	ret->constraints = arg->constraints;
 
 	if (!error) {
 		pr_debug(arg->ctx, "Resolved host `%s' successfully", arg->hostname);
@@ -101,19 +99,18 @@ static void* fastd_resolve_peer_handshake_do(void *varg) {
 	return NULL;
 }
 
-void fastd_resolve_peer_handshake(fastd_context *ctx, fastd_peer *peer) {
-	pr_debug(ctx, "Resolving host `%s' for peer %P...", peer->config->hostname, peer);
+void fastd_resolve_peer(fastd_context *ctx, const fastd_peer_config *peer) {
+	pr_debug(ctx, "Resolving host `%s' for peer `%s'...", peer->hostname, peer->name);
 
 	resolv_arg *arg = malloc(sizeof(resolv_arg));
 
 	arg->ctx = ctx;
 	arg->master_thread = pthread_self();
-	arg->hostname = strdup(peer->config->hostname);
-	arg->af = peer->config->address.sa.sa_family;
-	arg->port = ntohs(peer->config->address.in.sin_port);
+	arg->hostname = strdup(peer->hostname);
+	arg->constraints = peer->address;
 
 	pthread_t thread;
-	if (pthread_create(&thread, NULL, fastd_resolve_peer_handshake_do, arg) != 0) {
+	if (pthread_create(&thread, NULL, resolve_peer, arg) != 0) {
 		pr_error_errno(ctx, "unable to create resolver thread");
 		free(arg->hostname);
 		free(arg);
-- 
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