commit aba7bb705a69697ade1cff24e6693db2cb87236a Author: Nick Mathewson nickm@torproject.org Date: Tue May 3 22:22:20 2011 -0400

Set SO_REUSEADDR on all sockets, not just listeners

See bug 2850 for rationale: it appears that on some busy exits, the OS decides that every single port is now unusable because they have been all used too recently. --- changes/bug2850 | 5 +++++ src/or/connection.c | 34 +++++++++++++++++++++++----------- 2 files changed, 28 insertions(+), 11 deletions(-)

diff --git a/changes/bug2850 b/changes/bug2850 new file mode 100644 index 0000000..77ccbfa --- /dev/null +++ b/changes/bug2850 @@ -0,0 +1,5 @@ + - Minor features + o Set SO_REUSEADDR on all sockets, not just listeners. This should + help busy exit nodes avoid running out of useable ports just because + all the ports have been used in the near past. Resolves issue 2850. + diff --git a/src/or/connection.c b/src/or/connection.c index 6e7bbd5..e90e13f 100644 --- a/src/or/connection.c +++ b/src/or/connection.c @@ -851,6 +851,25 @@ warn_too_many_conns(void) } }

+/** Tell the TCP stack that it shouldn't wait for a long time after + * <b>sock</b> has closed before reusing its port. */ +static void +make_socket_reuseable(int sock) +{ +#ifdef MS_WINDOWS + (void) sock; +#else + int one=1; + + /* REUSEADDR on normal places means you can rebind to the port + * right after somebody else has let it go. But REUSEADDR on win32 + * means you can bind to the port _even when somebody else + * already has it bound_. So, don't do that on Win32. */ + setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void*) &one, + (socklen_t)sizeof(one)); +#endif +} + /** Bind a new non-blocking socket listening to the socket described * by <b>listensockaddr</b>. * @@ -873,9 +892,6 @@ connection_create_listener(struct sockaddr *listensockaddr, socklen_t socklen,

if (listensockaddr->sa_family == AF_INET) { int is_tcp = (type != CONN_TYPE_AP_DNS_LISTENER); -#ifndef MS_WINDOWS - int one=1; -#endif if (is_tcp) start_reading = 1;

@@ -893,14 +909,7 @@ connection_create_listener(struct sockaddr *listensockaddr, socklen_t socklen, goto err; }

-#ifndef MS_WINDOWS - /* REUSEADDR on normal places means you can rebind to the port - * right after somebody else has let it go. But REUSEADDR on win32 - * means you can bind to the port _even when somebody else - * already has it bound_. So, don't do that on Win32. */ - setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (void*) &one, - (socklen_t)sizeof(one)); -#endif + make_socket_reuseable(s);

if (bind(s,listensockaddr,socklen) < 0) { const char *helpfulhint = ""; @@ -1088,6 +1097,7 @@ connection_handle_listener_read(connection_t *conn, int new_type) "Connection accepted on socket %d (child of fd %d).", news,conn->s);

+ make_socket_reuseable(news); set_socket_nonblocking(news);

if (options->ConstrainedSockets) @@ -1297,6 +1307,8 @@ connection_connect(connection_t *conn, const char *address, log_debug(LD_NET, "Connecting to %s:%u.", escaped_safe_str_client(address), port);

+ make_socket_reuseable(s); + if (connect(s, dest_addr, dest_addr_len) < 0) { int e = tor_socket_errno(s); if (!ERRNO_IS_CONN_EINPROGRESS(e)) {