Trigger handshake when unexpected data is received from a floating peer

7 files changed, 72 insertions, 6 deletions

diff --git a/src/handshake.c b/src/handshake.c
index ce8895d..839951b 100644
--- a/src/handshake.c
+++ b/src/handshake.c
@@ -122,8 +122,10 @@ void fastd_handshake_handle(fastd_context *ctx, fastd_peer *peer, fastd_buffer b
 
 	handshake.req_id = packet->req_id;
 
-	if (handshake.records[RECORD_HANDSHAKE_TYPE].length != 1)
+	if (handshake.records[RECORD_HANDSHAKE_TYPE].length != 1) {
+		pr_debug(ctx, "received handshake without handshake type from %P", peer);
 		goto end_free;
+	}
 
 	handshake.type = AS_UINT8(handshake.records[RECORD_HANDSHAKE_TYPE]);
 
diff --git a/src/peer.c b/src/peer.c
index 7fe8c0e..74f5649 100644
--- a/src/peer.c
+++ b/src/peer.c
@@ -169,6 +169,8 @@ fastd_peer* fastd_peer_set_established_merge(fastd_context *ctx, fastd_peer *per
 		}
 	}
 
+	fastd_task_replace_peer(ctx, temp_peer, perm_peer);
+
 	fastd_peer_reset(ctx, temp_peer);
 
 	pr_info(ctx, "Connection with %P established.", perm_peer);
diff --git a/src/protocol_ec25519_fhmqvc_xsalsa20_poly1305.c b/src/protocol_ec25519_fhmqvc_xsalsa20_poly1305.c
index a7a635c..32c459a 100644
--- a/src/protocol_ec25519_fhmqvc_xsalsa20_poly1305.c
+++ b/src/protocol_ec25519_fhmqvc_xsalsa20_poly1305.c
@@ -561,8 +561,13 @@ static void protocol_handshake_handle(fastd_context *ctx, fastd_peer *peer, cons
 		}
 
 		if (peer->protocol_state->initiating_handshake->peer_config != peer_config) {
-			pr_debug(ctx, "received handshake response with wrong sender key from %P", peer);
-			return;
+			if (peer->protocol_state->initiating_handshake->peer_config) {
+				pr_debug(ctx, "received handshake response with wrong sender key from %P", peer);
+				return;
+			}
+			else {
+				peer->protocol_state->initiating_handshake->peer_config = peer_config;
+			}
 		}
 
 		if (memcmp(peer->protocol_state->initiating_handshake->public_key.p, handshake->records[RECORD_RECEIPIENT_HANDSHAKE_KEY].data, PUBLICKEYBYTES) != 0) {
@@ -606,14 +611,21 @@ static void protocol_handshake_handle(fastd_context *ctx, fastd_peer *peer, cons
 }
 
 static void protocol_handle_recv(fastd_context *ctx, fastd_peer *peer, fastd_buffer buffer) {
-	if (!fastd_peer_is_established(peer))
+	if (!fastd_peer_is_established(peer)) {
+		pr_debug(ctx, "received unexpected packet from %P", peer);
+
+		if (fastd_peer_is_temporary(peer)) {
+			pr_debug(ctx, "sending handshake to temporary peer %P", peer);
+			fastd_task_schedule_handshake(ctx, peer, 0);
+		}
+
 		goto end;
+	}
 
 	if (buffer.len < NONCEBYTES)
 		goto end;
 
 	if (!peer->protocol_state || !is_session_valid(ctx, &peer->protocol_state->session)) {
-		pr_debug(ctx, "received unexpected packet from %P", peer);
 		goto end;
 	}
 
@@ -644,7 +656,7 @@ static void protocol_handle_recv(fastd_context *ctx, fastd_peer *peer, fastd_buf
 
 		if (!is_nonce_valid(nonce, session->receive_nonce)) {
 			pr_debug(ctx, "received packet with invalid nonce from %P", peer);
-
+			fastd_buffer_free(recv_buffer);
 			goto end;
 		}
 
diff --git a/src/queue.c b/src/queue.c
index 2509538..70ee54b 100644
--- a/src/queue.c
+++ b/src/queue.c
@@ -85,3 +85,13 @@ void fastd_queue_filter(fastd_context *ctx, fastd_queue *queue, bool (*pred)(fas
 			entry = &(*entry)->next;
 	}
 }
+
+bool fastd_queue_has_entry(fastd_context *ctx, fastd_queue *queue, bool (*pred)(fastd_queue_entry*, void*), void *extra) {
+	fastd_queue_entry *entry;
+	for (entry = queue->head; entry; entry = entry->next) {
+		if (pred(entry, extra))
+			return true;
+	}
+
+	return false;
+}
diff --git a/src/queue.h b/src/queue.h
index 50456ee..8e93e0e 100644
--- a/src/queue.h
+++ b/src/queue.h
@@ -50,5 +50,6 @@ void fastd_queue_put(fastd_context *ctx, fastd_queue *queue, fastd_queue_entry *
 fastd_queue_entry* fastd_queue_get(fastd_context *ctx, fastd_queue *queue);
 int fastd_queue_timeout(fastd_context *ctx, fastd_queue *queue);
 void fastd_queue_filter(fastd_context *ctx, fastd_queue *queue, bool (*pred)(fastd_queue_entry*, void*), void *extra);
+bool fastd_queue_has_entry(fastd_context *ctx, fastd_queue *queue, bool (*pred)(fastd_queue_entry*, void*), void *extra);
 
 #endif /* _FASTD_QUEUE_H_ */
diff --git a/src/task.c b/src/task.c
index b4004ef..9526508 100644
--- a/src/task.c
+++ b/src/task.c
@@ -60,7 +60,22 @@ void fastd_task_put_handle_recv(fastd_context *ctx, fastd_peer *peer, fastd_buff
 	fastd_queue_put(ctx, &ctx->task_queue, &task->entry, 0);
 }
 
+static bool is_handshake(fastd_queue_entry *data, void *extra) {
+	fastd_task *task = container_of(data, fastd_task, entry);
+	fastd_peer *peer = extra;
+
+	if (task->peer != peer)
+		return true;
+
+	return (task->type == TASK_HANDSHAKE);
+}
+
 void fastd_task_schedule_handshake(fastd_context *ctx, fastd_peer *peer, int timeout) {
+	if (fastd_queue_has_entry(ctx, &ctx->task_queue, is_handshake, peer)) {
+		pr_debug(ctx, "not sending a handshake to %P, there still is one queued", peer);
+		return;
+	}
+
 	fastd_task *task = malloc(sizeof(fastd_task));
 
 	task->type = TASK_HANDSHAKE;
@@ -69,6 +84,29 @@ void fastd_task_schedule_handshake(fastd_context *ctx, fastd_peer *peer, int tim
 	fastd_queue_put(ctx, &ctx->task_queue, &task->entry, timeout);
 }
 
+typedef struct _replace_peer_extra {
+	fastd_peer *old_peer;
+	fastd_peer *new_peer;
+} replace_peer_extra;
+
+
+static bool replace_peer(fastd_queue_entry *data, void *extra) {
+	replace_peer_extra *e = extra;
+	fastd_task *task = container_of(data, fastd_task, entry);
+	fastd_peer *old_peer = e->old_peer;
+	fastd_peer *new_peer = e->new_peer;
+
+	if (task->peer == old_peer)
+		task->peer = new_peer;
+
+	return true;
+}
+
+void fastd_task_replace_peer(fastd_context *ctx, fastd_peer *old_peer, fastd_peer *new_peer) {
+	replace_peer_extra extra = {old_peer, new_peer};
+	fastd_queue_filter(ctx, &ctx->task_queue, replace_peer, &extra);
+}
+
 typedef struct _delete_task_extra {
 	fastd_peer *peer;
 	bool handshake_only;
diff --git a/src/task.h b/src/task.h
index f5634d9..312c8f9 100644
--- a/src/task.h
+++ b/src/task.h
@@ -78,6 +78,7 @@ void fastd_task_put_handle_recv(fastd_context *ctx, fastd_peer *peer, fastd_buff
 
 void fastd_task_schedule_handshake(fastd_context *ctx, fastd_peer *peer, int timeout);
 
+void fastd_task_replace_peer(fastd_context *ctx, fastd_peer *old_peer, fastd_peer *new_peer);
 void fastd_task_delete_peer(fastd_context *ctx, fastd_peer *peer);
 void fastd_task_delete_peer_handshakes(fastd_context *ctx, fastd_peer *peer);