Add get_interface_address[6]_list for a list of interface IP addresses

Add get_interface_address[6]_list by refactoring
get_interface_address6. Add unit tests for new and existing functions.

Preparation for ticket 17027. Patch by "teor".
Patch on 42b8fb5a1523 (11 Nov 2007), released in 0.2.0.11-alpha.

1 files changed, 87 insertions, 20 deletions

diff --git a/src/common/address.c b/src/common/address.c
index dd336257ef..0614256521 100644
--- a/src/common/address.c
+++ b/src/common/address.c
@@ -1503,7 +1503,7 @@ get_interface_addresses_raw(int severity)
 }
 
 /** Return true iff <b>a</b> is a multicast address.  */
-static int
+STATIC int
 tor_addr_is_multicast(const tor_addr_t *a)
 {
   sa_family_t family = tor_addr_family(a);
@@ -1593,27 +1593,26 @@ get_interface_address6_via_udp_socket_hack(int severity,
   return r;
 }
 
-/** Set *<b>addr</b> to the IP address (if any) of whatever interface
- * connects to the Internet.  This address should only be used in checking
- * whether our address has changed.  Return 0 on success, -1 on failure.
+/** Set *<b>addr</b> to an arbitrary IP address (if any) of an interface that
+ * connects to the Internet.  Prefer public IP addresses to internal IP
+ * addresses.  This address should only be used in checking whether our
+ * address has changed, as it may be an internal IP address.  Return 0 on
+ * success, -1 on failure.
+ * Prefer get_interface_address6_list for a list of all addresses on all
+ * interfaces which connect to the Internet.
  */
 MOCK_IMPL(int,
 get_interface_address6,(int severity, sa_family_t family, tor_addr_t *addr))
 {
-  /* XXX really, this function should yield a smartlist of addresses. */
   smartlist_t *addrs;
   tor_assert(addr);
 
-  /* Try to do this the smart way if possible. */
-  if ((addrs = get_interface_addresses_raw(severity))) {
+  /* Get a list of public or internal IPs in arbitrary order */
+  if ((addrs = get_interface_address6_list(severity, family, 1))) {
     int rv = -1;
+    /* Find the first non-internal address, or the last internal address
+     * Ideally, we want the default route, see #12377 for details */
     SMARTLIST_FOREACH_BEGIN(addrs, tor_addr_t *, a) {
-      if (family != AF_UNSPEC && family != tor_addr_family(a))
-        continue;
-      if (tor_addr_is_loopback(a) ||
-          tor_addr_is_multicast(a))
-        continue;
-
       tor_addr_copy(addr, a);
       rv = 0;
 
@@ -1623,13 +1622,78 @@ get_interface_address6,(int severity, sa_family_t family, tor_addr_t *addr))
         break;
     } SMARTLIST_FOREACH_END(a);
 
-    SMARTLIST_FOREACH(addrs, tor_addr_t *, a, tor_free(a));
-    smartlist_free(addrs);
+    free_interface_address6_list(addrs);
     return rv;
   }
 
+  return -1;
+}
+
+/** Free a smartlist of IP addresses returned by get_interface_address6_list.
+ */
+void free_interface_address6_list(smartlist_t *addrs) {
+  SMARTLIST_FOREACH(addrs, tor_addr_t *, a, tor_free(a));
+  smartlist_free(addrs);
+}
+
+/** Return a smartlist of the IP addresses of type family from all interfaces
+ * on the server. Excludes loopback and multicast addresses. Only includes
+ * internal addresses if include_internal is true. (Note that a relay behind
+ * NAT may use an internal address to connect to the Internet.)
+ * An empty smartlist means that there are no addresses of the selected type
+ * matching these criteria.
+ * Returns NULL on failure.
+ * Use free_interface_address6_list to free the returned list.
+ */
+MOCK_IMPL(smartlist_t *,get_interface_address6_list,(int severity,
+                                                     sa_family_t family,
+                                                     int include_internal))
+{
+  smartlist_t *addrs;
+  tor_addr_t addr;
+
+  /* Try to do this the smart way if possible. */
+  if ((addrs = get_interface_addresses_raw(severity))) {
+    SMARTLIST_FOREACH_BEGIN(addrs, tor_addr_t *, a) {
+      if (family != AF_UNSPEC && family != tor_addr_family(a)){
+        SMARTLIST_DEL_CURRENT(addrs, a);
+        tor_free(a);
+        continue;
+      }
+
+      if (tor_addr_is_loopback(a) ||
+          tor_addr_is_multicast(a)) {
+        SMARTLIST_DEL_CURRENT(addrs, a);
+        tor_free(a);
+        continue;
+      }
+
+      if (!include_internal && tor_addr_is_internal(a, 0)){
+        SMARTLIST_DEL_CURRENT(addrs, a);
+        tor_free(a);
+        continue;
+      }
+    } SMARTLIST_FOREACH_END(a);
+  }
+
+  if (addrs && smartlist_len(addrs) > 0) {
+    return addrs;
+  }
+
+  /* if we removed all entries as unsuitable */
+  if (addrs) {
+    smartlist_free(addrs);
+  }
+
   /* Okay, the smart way is out. */
-  return get_interface_address6_via_udp_socket_hack(severity,family,addr);
+  get_interface_address6_via_udp_socket_hack(severity,family,&addr);
+  if (!include_internal && tor_addr_is_internal(&addr, 0)) {
+    return smartlist_new();
+  } else {
+    addrs = smartlist_new();
+    smartlist_add(addrs, tor_dup_addr(&addr));
+    return addrs;
+  }
 }
 
 /* ======
@@ -1871,10 +1935,13 @@ tor_dup_ip(uint32_t addr)
 }
 
 /**
- * Set *<b>addr</b> to the host-order IPv4 address (if any) of whatever
- * interface connects to the Internet.  This address should only be used in
- * checking whether our address has changed.  Return 0 on success, -1 on
- * failure.
+ * Set *<b>addr</b> to a host-order IPv4 address (if any) of an
+ * interface that connects to the Internet.  Prefer public IP addresses to
+ * internal IP addresses.  This address should only be used in checking
+ * whether our address has changed, as it may be an internal IPv4 address.
+ * Return 0 on success, -1 on failure.
+ * Prefer get_interface_address_list6 for a list of all IPv4 and IPv6
+ * addresses on all interfaces which connect to the Internet.
  */
 MOCK_IMPL(int,
 get_interface_address,(int severity, uint32_t *addr))