New consensus params "bwconnrate" and "bwconnburst"

...to let us
rate-limit client connections as they enter the network. It's
controlled in the consensus so we can turn it on and off for
experiments. It's starting out off. Based on proposal 163.

1 files changed, 29 insertions, 2 deletions

diff --git a/src/or/connection_or.c b/src/or/connection_or.c
index 84023f5a7e..6704af8f09 100644
--- a/src/or/connection_or.c
+++ b/src/or/connection_or.c
@@ -320,6 +320,19 @@ connection_or_finished_connecting(or_connection_t *or_conn)
   return 0;
 }
 
+/** Return 1 if identity digest <b>id_digest</b> is known to be a
+ * currently or recently running relay. Otherwise return 0. */
+static int
+connection_or_digest_is_known_relay(const char *id_digest)
+{
+  if (router_get_consensus_status_by_id(id_digest))
+    return 1; /* It's in the consensus: "yes" */
+  if (router_get_by_digest(id_digest))
+    return 1; /* Not in the consensus, but we have a descriptor for
+               * it. Probably it was in a recent consensus. "Yes". */
+  return 0;
+}
+
 /** If we don't necessarily know the router we're connecting to, but we
  * have an addr/port/id_digest, then fill in as much as we can. Start
  * by checking to see if this describes a router we know. */
@@ -331,10 +344,24 @@ connection_or_init_conn_from_address(or_connection_t *conn,
 {
   or_options_t *options = get_options();
   routerinfo_t *r = router_get_by_digest(id_digest);
-  conn->bandwidthrate = (int)options->BandwidthRate;
-  conn->read_bucket = conn->bandwidthburst = (int)options->BandwidthBurst;
   connection_or_set_identity_digest(conn, id_digest);
 
+  if (connection_or_digest_is_known_relay(id_digest)) {
+    /* It's in the consensus, or we have a descriptor for it meaning it
+     * was probably in a recent consensus. It's a recognized relay:
+     * give it full bandwidth. */
+    conn->bandwidthrate = (int)options->BandwidthRate;
+    conn->read_bucket = conn->bandwidthburst = (int)options->BandwidthBurst;
+  } else { /* Not a recognized relay. Squeeze it down based on the
+            * suggested bandwidth parameters in the consensus. */
+    conn->bandwidthrate =
+      (int)networkstatus_get_param(NULL, "bwconnrate",
+                                   (int)options->BandwidthRate);
+    conn->read_bucket = conn->bandwidthburst =
+      (int)networkstatus_get_param(NULL, "bwconnburst",
+                                   (int)options->BandwidthBurst);
+  }
+
   conn->_base.port = port;
   tor_addr_copy(&conn->_base.addr, addr);
   tor_addr_copy(&conn->real_addr, addr);