tor

commit 87b2ce6f848ec3a65a7a06ef1edce5a0652ad9a3
parent 4f038d224f5a3df5fb396eff0173bba0eec89127
Author: Alex Xu (Hello71) <alex_y_xu@yahoo.ca>
Date:   Sat, 21 May 2022 15:52:31 -0400

Trigger OOS on bind failures (fixes #40597)

Diffstat:
A
changes/issue40597
 | 
4
++++
M
src/core/mainloop/connection.c
 | 
24
+++++++++++++++---------

2 files changed, 19 insertions(+), 9 deletions(-)
diff --git a/changes/issue40597 b/changes/issue40597
@@ -0,0 +1,4 @@
+  o Minor features (relays):
+    - Trigger OOS when bind fails with EADDRINUSE. This improves fairness when
+      a large number of exit connections are requested, and properly signals
+      exhaustion to the network. Fixes issue 40597; patch by Alex Xu (Hello71).
diff --git a/src/core/mainloop/connection.c b/src/core/mainloop/connection.c
@@ -2224,21 +2224,27 @@ connection_connect_sockaddr,(connection_t *conn,
              tor_socket_strerror(errno));
   }
 
-  /*
-   * We've got the socket open; give the OOS handler a chance to check
-   * against configured maximum socket number, but tell it no exhaustion
-   * failure.
-   */
-  connection_check_oos(get_n_open_sockets(), 0);
-
   if (bindaddr && bind(s, bindaddr, bindaddr_len) < 0) {
     *socket_error = tor_socket_errno(s);
-    log_warn(LD_NET,"Error binding network socket: %s",
-             tor_socket_strerror(*socket_error));
+    if (ERRNO_IS_EADDRINUSE(*socket_error)) {
+      socket_failed_from_resource_exhaustion();
+      connection_check_oos(get_n_open_sockets(), 1);
+    } else {
+      log_warn(LD_NET,"Error binding network socket: %s",
+               tor_socket_strerror(*socket_error));
+      connection_check_oos(get_n_open_sockets(), 0);
+    }
     tor_close_socket(s);
     return -1;
   }
 
+  /*
+   * We've got the socket open and bound; give the OOS handler a chance to
+   * check against configured maximum socket number, but tell it no exhaustion
+   * failure.
+   */
+  connection_check_oos(get_n_open_sockets(), 0);
+
   tor_assert(options);
   if (options->ConstrainedSockets)
     set_constrained_socket_buffers(s, (int)options->ConstrainedSockSize);