Apply rate-limiting to the lowest bufferevent in the stack.

When we're doing filtering ssl bufferevents, we want the rate-limits
to apply to the lowest level of the bufferevent stack, so that we're
actually limiting bytes sent on the network. Otherwise, we'll read
from the network aggressively, and only limit stuff as we process it.

diff --git a/changes/bug3804 b/changes/bug3804
new file mode 100644 (file)
index 0000000..d498db8
--- /dev/null
+++ b/changes/bug3804
@@ -0,0 +1,4 @@
+  o Major bugfixes (bufferevents):
+    - Apply rate-limiting only at the bottom of a chain of filtering
+      bufferevents. This prevents us from filling up internal memory
+      buffers. Bugfix on 0.2.3.1-alpha; fixes bug 3804.

diff --git a/src/common/compat_libevent.c b/src/common/compat_libevent.c
index 595742f9619a04f53e3ae009f21eff3482bb44f7..beae9502dae6c300c0693549a84c7622f832e099 100644 (file)
--- a/src/common/compat_libevent.c
+++ b/src/common/compat_libevent.c
@@ -20,6 +20,9 @@
 #ifdef HAVE_EVENT2_EVENT_H
 #include <event2/event.h>
 #include <event2/thread.h>
+#ifdef USE_BUFFEREVENTS
+#include <event2/bufferevent.h>
+#endif
 #else
 #include <event.h>
 #endif
@@ -614,5 +617,28 @@ tor_libevent_get_one_tick_timeout(void)
   }
   return one_tick;
 }
+
+static struct bufferevent *
+tor_get_root_bufferevent(struct bufferevent *bev)
+{
+  struct bufferevent *u;
+  while ((u = bufferevent_get_underlying(bev)) != NULL)
+    bev = u;
+  return bev;
+}
+
+int
+tor_set_bufferevent_rate_limit(struct bufferevent *bev,
+                               struct ev_token_bucket_cfg *cfg)
+{
+  return bufferevent_set_rate_limit(tor_get_root_bufferevent(bev), cfg);
+}
+
+int
+tor_add_bufferevent_to_rate_limit_group(struct bufferevent *bev,
+                                        struct bufferevent_rate_limit_group *g)
+{
+  return bufferevent_add_to_rate_limit_group(tor_get_root_bufferevent(bev), g);
+}
 #endif
 

diff --git a/src/common/compat_libevent.h b/src/common/compat_libevent.h
index bbe105bf403a67cdc8ec3ee4e4d9b9f77e98cd06..15b0fc273b08a1966c4896e9f30e44a352cae388 100644 (file)
--- a/src/common/compat_libevent.h
+++ b/src/common/compat_libevent.h
@@ -10,6 +10,8 @@ struct event;
 struct event_base;
 #ifdef USE_BUFFEREVENTS
 struct bufferevent;
+struct ev_token_bucket_cfg;
+struct bufferevent_rate_limit_group;
 #endif
 
 #ifdef HAVE_EVENT2_EVENT_H
@@ -74,6 +76,10 @@ const char *tor_libevent_get_version_str(void);
 #define TOR_LIBEVENT_TICKS_PER_SECOND 3
 const struct timeval *tor_libevent_get_one_tick_timeout(void);
 int tor_libevent_using_iocp_bufferevents(void);
+int tor_set_bufferevent_rate_limit(struct bufferevent *bev,
+                                   struct ev_token_bucket_cfg *cfg);
+int tor_add_bufferevent_to_rate_limit_group(struct bufferevent *bev,
+                                   struct bufferevent_rate_limit_group *g);
 #endif
 
 #endif

diff --git a/src/or/connection.c b/src/or/connection.c
index f8f82a30ddcfd832d3d906bdb2bf1c0faf30074e..c4cbef4c9dcf1b45461c08d3f551adba0b416302 100644 (file)
--- a/src/or/connection.c
+++ b/src/or/connection.c
@@ -2509,7 +2509,7 @@ connection_enable_rate_limiting(connection_t *conn)
   if (conn->bufev) {
     if (!global_rate_limit)
       connection_bucket_init();
-    bufferevent_add_to_rate_limit_group(conn->bufev, global_rate_limit);
+    tor_add_bufferevent_to_rate_limit_group(conn->bufev, global_rate_limit);
   }
 }
 

diff --git a/src/or/connection_or.c b/src/or/connection_or.c
index e66d36a2f3060a7b56040805b40f6495c9f02bd1..a75444e1ed01121bdd5efca89f1fcd8fee1df555 100644 (file)
--- a/src/or/connection_or.c
+++ b/src/or/connection_or.c
@@ -585,7 +585,7 @@ connection_or_update_token_buckets_helper(or_connection_t *conn, int reset,
                                   burst, tick);
     old_cfg = conn->bucket_cfg;
     if (conn->_base.bufev)
-      bufferevent_set_rate_limit(conn->_base.bufev, cfg);
+      tor_set_bufferevent_rate_limit(conn->_base.bufev, cfg);
     if (old_cfg)
       ev_token_bucket_cfg_free(old_cfg);
     conn->bucket_cfg = cfg;
@@ -1102,7 +1102,7 @@ connection_tls_start_handshake(or_connection_t *conn, int receiving)
     }
     conn->_base.bufev = b;
     if (conn->bucket_cfg)
-      bufferevent_set_rate_limit(conn->_base.bufev, conn->bucket_cfg);
+      tor_set_bufferevent_rate_limit(conn->_base.bufev, conn->bucket_cfg);
     connection_enable_rate_limiting(TO_CONN(conn));
 
     connection_configure_bufferevent_callbacks(TO_CONN(conn));