From aefe87865b47c80b415e2e01ca27b11b208b842d Mon Sep 17 00:00:00 2001
From: Guus Sliepen <guus@meshlink.io>
Date: Thu, 17 Dec 2015 18:44:21 +0100
Subject: [PATCH] Use free_known_addresses() to free memory allocated by
 get_known_addresses().

We know what struct addrinfo looks like, but the standard says nothing about
how it is allocated. So we cannot trust freeaddrinfo() to work correctly on
the struct addrinfo list we allocated ourselves in get_known_addresses().
To make a distinction by allocations from the latter and from str2addrinfo(),
we keep two pointers (*ai and *aip) in struct outgoing, and use the freeing
function that is appropriate for each.
---
 src/net.h        |  3 +-
 src/net_socket.c | 89 ++++++++++++++++++++++++++++--------------------
 2 files changed, 55 insertions(+), 37 deletions(-)

diff --git a/src/net.h b/src/net.h
index 6a361a05..6c5a0a6f 100644
--- a/src/net.h
+++ b/src/net.h
@@ -63,8 +63,9 @@ typedef struct outgoing_t {
 	int timeout;
 	struct splay_tree_t *config_tree;
 	struct config_t *cfg;
-	struct addrinfo *ai;
+	struct addrinfo *ai; // addresses from config files
 	struct addrinfo *aip;
+	struct addrinfo *nai; // addresses known via other online nodes (use free_known_addresses())
 	timeout_t ev;
 	struct meshlink_handle *mesh;
 } outgoing_t;
diff --git a/src/net_socket.c b/src/net_socket.c
index 06394781..b147bfdf 100644
--- a/src/net_socket.c
+++ b/src/net_socket.c
@@ -355,13 +355,55 @@ static void handle_meta_io(event_loop_t *loop, void *data, int flags) {
 		handle_meta_connection_data(mesh, c);
 }
 
+// Find edges pointing to this node, and use them to build a list of unique, known addresses.
+static struct addrinfo *get_known_addresses(node_t *n) {
+	struct addrinfo *ai = NULL;
+
+	for splay_each(edge_t, e, n->edge_tree) {
+		if(!e->reverse)
+			continue;
+
+		bool found = false;
+		for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
+			if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
+				found = true;
+				break;
+			}
+		}
+		if(found)
+			continue;
+
+		// Create a new struct addrinfo, and put it at the head of the list.
+		struct addrinfo *nai = xzalloc(sizeof *nai + SALEN(e->reverse->address.sa));
+		nai->ai_next = ai;
+		ai = nai;
+
+		ai->ai_family = e->reverse->address.sa.sa_family;
+		ai->ai_socktype = SOCK_STREAM;
+		ai->ai_protocol = IPPROTO_TCP;
+		ai->ai_addrlen = SALEN(e->reverse->address.sa);
+		ai->ai_addr = (struct sockaddr *)(nai + 1);
+		memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
+	}
+
+	return ai;
+}
+
+// Free struct addrinfo list from get_known_addresses().
+static void free_known_addresses(struct addrinfo *ai) {
+	for(struct addrinfo *aip = ai, *next; aip; aip = next) {
+		next = aip->ai_next;
+		free(aip);
+	}
+}
+
 bool do_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 	char *address, *port, *space;
 	struct addrinfo *proxyai = NULL;
 	int result;
 
 begin:
-	if(!outgoing->ai) {
+	if(!outgoing->ai && !outgoing->nai) {
 		if(!outgoing->cfg) {
 			logger(mesh, MESHLINK_ERROR, "Could not set up a meta connection to %s", outgoing->name);
 			retry_outgoing(mesh, outgoing);
@@ -395,6 +437,11 @@ begin:
 		if(outgoing->ai)
 			freeaddrinfo(outgoing->ai);
 		outgoing->ai = NULL;
+
+		if(outgoing->nai)
+			free_known_addresses(outgoing->nai);
+		outgoing->nai = NULL;
+
 		goto begin;
 	}
 
@@ -476,39 +523,6 @@ begin:
 	return true;
 }
 
-// Find edges pointing to this node, and use them to build a list of unique, known addresses.
-static struct addrinfo *get_known_addresses(node_t *n) {
-	struct addrinfo *ai = NULL;
-
-	for splay_each(edge_t, e, n->edge_tree) {
-		if(!e->reverse)
-			continue;
-
-		bool found = false;
-		for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
-			if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
-				found = true;
-				break;
-			}
-		}
-		if(found)
-			continue;
-
-		struct addrinfo *nai = xzalloc(sizeof *nai);
-		if(ai)
-			ai->ai_next = nai;
-		ai = nai;
-		ai->ai_family = e->reverse->address.sa.sa_family;
-		ai->ai_socktype = SOCK_STREAM;
-		ai->ai_protocol = IPPROTO_TCP;
-		ai->ai_addrlen = SALEN(e->reverse->address.sa);
-		ai->ai_addr = xmalloc(ai->ai_addrlen);
-		memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
-	}
-
-	return ai;
-}
-
 void setup_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 	bool blacklisted = false;
 	timeout_del(&mesh->loop, &outgoing->ev);
@@ -532,8 +546,8 @@ void setup_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 
 	if(!outgoing->cfg) {
 		if(n)
-			outgoing->aip = outgoing->ai = get_known_addresses(n);
-		if(!outgoing->ai) {
+			outgoing->aip = outgoing->nai = get_known_addresses(n);
+		if(!outgoing->nai) {
 			logger(mesh, MESHLINK_ERROR, "No address known for %s", outgoing->name);
 			return;
 		}
@@ -648,6 +662,9 @@ static void free_outgoing(outgoing_t *outgoing) {
 	if(outgoing->ai)
 		freeaddrinfo(outgoing->ai);
 
+	if(outgoing->nai)
+		free_known_addresses(outgoing->nai);
+
 	if(outgoing->config_tree)
 		exit_configuration(&outgoing->config_tree);
 
-- 
2.39.2