Avoid calling node_get_all_orports() from node_is_a_configured_bridge()

All node_get_all_orports() does is allocate and return a smartlist
with at most two tor_addr_port_t members that match ORPort's of
node configuration. This is harmful for memory efficiency, as it
allocates the same stuff every time it is called. However,
node_is_a_configured_bridge() does not need to call it, as it
already has all the information to check if there is configured
bridge for a given node.

The new code is arranged in a way that hopefully makes each succeeding
linear search through bridge_list less likely.

2 files changed, 102 insertions, 9 deletions

diff --git a/changes/bug27224 b/changes/bug27224
new file mode 100644
index 0000000000..d43890b818
--- /dev/null
+++ b/changes/bug27224
@@ -0,0 +1,5 @@
+  o Minor bugfixes (performance)::
+    - Rework node_is_a_configured_bridge() to no longer
+      call node_get_all_orports(), which was performing too
+      many memory allocations. Fixes bug 27224; bugfix on
+      0.2.3.9.
diff --git a/src/feature/client/bridges.c b/src/feature/client/bridges.c
index 4bffe16036..7f4422f787 100644
--- a/src/feature/client/bridges.c
+++ b/src/feature/client/bridges.c
@@ -31,6 +31,7 @@
 #include "feature/nodelist/node_st.h"
 #include "feature/nodelist/routerinfo_st.h"
 #include "feature/nodelist/routerstatus_st.h"
+#include "feature/nodelist/microdesc_st.h"
 
 /** Information about a configured bridge. Currently this just matches the
  * ones in the torrc file, but one day we may be able to learn about new
@@ -283,17 +284,105 @@ routerinfo_is_a_configured_bridge(const routerinfo_t *ri)
   return get_configured_bridge_by_routerinfo(ri) ? 1 : 0;
 }
 
-/** Return 1 if <b>node</b> is one of our configured bridges, else 0. */
+/**
+ * Return 1 iff <b>bridge_list</b> contains entry matching
+ * given; IPv4 address in host byte order (<b>ipv4_addr</b>
+ * and <b>port</b> (and no identity digest) OR it contains an
+ * entry whose identity matches <b>digest</b>. Otherwise,
+ * return 0.
+ */
+static int
+bridge_exists_with_ipv4h_addr_and_port(const uint32_t ipv4_addr,
+                                       const uint16_t port,
+                                       const char *digest)
+{
+  tor_addr_t node_ipv4;
+
+  if (tor_addr_port_is_valid_ipv4h(ipv4_addr, port, 0)) {
+    tor_addr_from_ipv4h(&node_ipv4, ipv4_addr);
+
+   bridge_info_t *bridge =
+    get_configured_bridge_by_addr_port_digest(&node_ipv4,
+                                              port,
+                                              digest);
+
+   return (bridge != NULL);
+  }
+
+  return 0;
+}
+
+/**
+ * Return 1 iff <b>bridge_list</b> contains entry matching given
+ * <b>ipv6_addr</b> and <b>port</b> (and no identity digest) OR
+ * it contains an  entry whose identity matches <b>digest</b>.
+ * Otherwise, return 0.
+ */
+static int
+bridge_exists_with_ipv6_addr_and_port(const tor_addr_t *ipv6_addr,
+                                      const uint16_t port,
+                                      const char *digest)
+{
+  if (!tor_addr_port_is_valid(ipv6_addr, port, 0))
+    return 0;
+
+  bridge_info_t *bridge =
+   get_configured_bridge_by_addr_port_digest(ipv6_addr,
+                                             port,
+                                             digest);
+
+  return (bridge != NULL);
+}
+
+/** Return 1 if <b>node</b> is one of our configured bridges, else 0.
+ * More specifically, return 1 iff: a bridge_info_t object exists in
+ * <b>bridge_list</b> such that: 1) It's identity is equal to node
+ * identity OR 2) It's identity digest is zero, but it matches
+ * address and port of any ORPort in the node.
+ */
 int
 node_is_a_configured_bridge(const node_t *node)
 {
-  int retval = 0;
-  smartlist_t *orports = node_get_all_orports(node);
-  retval = get_configured_bridge_by_orports_digest(node->identity,
-                                                   orports) != NULL;
-  SMARTLIST_FOREACH(orports, tor_addr_port_t *, p, tor_free(p));
-  smartlist_free(orports);
-  return retval;
+  /* First, let's try searching for a bridge with matching identity. */
+  if (BUG(tor_digest_is_zero(node->identity)))
+    return 0;
+
+  if (find_bridge_by_digest(node->identity) != NULL)
+    return 1;
+
+  /* At this point, we have established that no bridge exists with
+   * matching identity digest. However, we still pass it into
+   * bridge_exists_* functions because we want further code to
+   * check for absence of identity digest in a bridge.
+   */
+  if (node->ri) {
+    if (bridge_exists_with_ipv4h_addr_and_port(node->ri->addr,
+                                               node->ri->or_port,
+                                               node->identity))
+      return 1;
+
+    if (bridge_exists_with_ipv6_addr_and_port(&node->ri->ipv6_addr,
+                                              node->ri->ipv6_orport,
+                                              node->identity))
+      return 1;
+  } else if (node->rs) {
+    if (bridge_exists_with_ipv4h_addr_and_port(node->rs->addr,
+                                               node->rs->or_port,
+                                               node->identity))
+      return 1;
+
+    if (bridge_exists_with_ipv6_addr_and_port(&node->rs->ipv6_addr,
+                                              node->rs->ipv6_orport,
+                                              node->identity))
+      return 1;
+  }  else if (node->md) {
+    if (bridge_exists_with_ipv6_addr_and_port(&node->md->ipv6_addr,
+                                              node->md->ipv6_orport,
+                                              node->identity))
+      return 1;
+  }
+
+  return 0;
 }
 
 /** We made a connection to a router at <b>addr</b>:<b>port</b>
@@ -934,4 +1023,3 @@ bridges_free_all(void)
   smartlist_free(bridge_list);
   bridge_list = NULL;
 }
-