Stub out connection_handle_oos() and call it from places we can change the socket count or thresholds

This commit is contained in:
Andrea Shepard 2016-06-30 10:43:44 +00:00
parent 1c0c0022d8
commit 34d9d02150
3 changed files with 112 additions and 1 deletions

View File

@ -1358,6 +1358,9 @@ options_act_reversible(const or_options_t *old_options, char **msg)
options->ConnLimit, options->ConnLimit_,
options->ConnLimit_high_thresh,
options->ConnLimit_low_thresh);
/* Give the OOS handler a chance with the new thresholds */
connection_handle_oos(get_n_open_sockets(), 0);
}
goto done;

View File

@ -1090,6 +1090,7 @@ connection_listener_new(const struct sockaddr *listensockaddr,
int start_reading = 0;
static int global_next_session_group = SESSION_GROUP_FIRST_AUTO;
tor_addr_t addr;
int exhaustion = 0;
if (listensockaddr->sa_family == AF_INET ||
listensockaddr->sa_family == AF_INET6) {
@ -1108,6 +1109,11 @@ connection_listener_new(const struct sockaddr *listensockaddr,
int e = tor_socket_errno(s);
if (ERRNO_IS_RESOURCE_LIMIT(e)) {
warn_too_many_conns();
/*
* We'll call the OOS handler at the error exit, so set the
* exhaustion flag for it.
*/
exhaustion = 1;
} else {
log_warn(LD_NET, "Socket creation failed: %s",
tor_socket_strerror(e));
@ -1226,6 +1232,11 @@ connection_listener_new(const struct sockaddr *listensockaddr,
int e = tor_socket_errno(s);
if (ERRNO_IS_RESOURCE_LIMIT(e)) {
warn_too_many_conns();
/*
* We'll call the OOS handler at the error exit, so set the
* exhaustion flag for it.
*/
exhaustion = 1;
} else {
log_warn(LD_NET,"Socket creation failed: %s.", strerror(e));
}
@ -1344,6 +1355,12 @@ connection_listener_new(const struct sockaddr *listensockaddr,
dnsserv_configure_listener(conn);
}
/*
* Normal exit; call the OOS handler since connection count just changed;
* the exhaustion flag will always be zero here though.
*/
connection_handle_oos(get_n_open_sockets(), 0);
return conn;
err:
@ -1352,6 +1369,9 @@ connection_listener_new(const struct sockaddr *listensockaddr,
if (conn)
connection_free(conn);
/* Call the OOS handler, indicate if we saw an exhaustion-related error */
connection_handle_oos(get_n_open_sockets(), exhaustion);
return NULL;
}
@ -1442,21 +1462,34 @@ connection_handle_listener_read(connection_t *conn, int new_type)
if (!SOCKET_OK(news)) { /* accept() error */
int e = tor_socket_errno(conn->s);
if (ERRNO_IS_ACCEPT_EAGAIN(e)) {
return 0; /* they hung up before we could accept(). that's fine. */
/*
* they hung up before we could accept(). that's fine.
*
* give the OOS handler a chance to run though
*/
connection_handle_oos(get_n_open_sockets(), 0);
return 0;
} else if (ERRNO_IS_RESOURCE_LIMIT(e)) {
warn_too_many_conns();
/* Exhaustion; tell the OOS handler */
connection_handle_oos(get_n_open_sockets(), 1);
return 0;
}
/* else there was a real error. */
log_warn(LD_NET,"accept() failed: %s. Closing listener.",
tor_socket_strerror(e));
connection_mark_for_close(conn);
/* Tell the OOS handler about this too */
connection_handle_oos(get_n_open_sockets(), 0);
return -1;
}
log_debug(LD_NET,
"Connection accepted on socket %d (child of fd %d).",
(int)news,(int)conn->s);
/* We accepted a new conn; run OOS handler */
connection_handle_oos(get_n_open_sockets(), 0);
if (make_socket_reuseable(news) < 0) {
if (tor_socket_errno(news) == EINVAL) {
/* This can happen on OSX if we get a badly timed shutdown. */
@ -1661,12 +1694,18 @@ connection_connect_sockaddr,(connection_t *conn,
s = tor_open_socket_nonblocking(protocol_family, SOCK_STREAM, proto);
if (! SOCKET_OK(s)) {
/*
* Early OOS handler calls; it matters if it's an exhaustion-related
* error or not.
*/
*socket_error = tor_socket_errno(s);
if (ERRNO_IS_RESOURCE_LIMIT(*socket_error)) {
warn_too_many_conns();
connection_handle_oos(get_n_open_sockets(), 1);
} else {
log_warn(LD_NET,"Error creating network socket: %s",
tor_socket_strerror(*socket_error));
connection_handle_oos(get_n_open_sockets(), 0);
}
return -1;
}
@ -1676,6 +1715,13 @@ 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 configuured maximum socket number, but tell it no exhaustion
* failure.
*/
connection_handle_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",
@ -4454,6 +4500,66 @@ connection_reached_eof(connection_t *conn)
}
}
/** Out-of-Sockets handler; n_socks is the current number of open
* sockets, and failed is non-zero if a socket exhaustion related
* error immediately preceded this call. This is where to do
* circuit-killing heuristics as needed.
*/
void
connection_handle_oos(int n_socks, int failed)
{
int target_n_socks = 0;
/* Sanity-check args */
tor_assert(n_socks >= 0);
/*
* Make some log noise; keep it at debug level since this gets a chance
* to run on every connection attempt.
*/
log_debug(LD_NET,
"Running the OOS handler (%d open sockets, %s)",
n_socks, (failed != 0) ? "exhaustion seen" : "no exhaustion");
/*
* Check if we're really handling an OOS condition, and if so decide how
* many sockets we want to get down to.
*/
if (n_socks > get_options()->ConnLimit_high_thresh) {
/* Try to get down to the low threshold */
target_n_socks = get_options()->ConnLimit_low_thresh;
log_notice(LD_NET,
"Current number of sockets %d is greater than configured "
"limit %d; OOS handler trying to get down to %d",
n_socks, get_options()->ConnLimit_high_thresh,
target_n_socks);
} else if (failed) {
/*
* If we're not at the limit but we hit a socket exhaustion error, try to
* drop some (but not as aggressively as ConnLimit_low_threshold, which is
* 3/4 of ConnLimit_)
*/
target_n_socks = (n_socks * 9) / 10;
log_notice(LD_NET,
"We saw socket exhaustion at %d open sockets; OOS handler "
"trying to get down to %d",
n_socks, target_n_socks);
}
if (target_n_socks > 0) {
/*
* It's an OOS!
*
* TODO count moribund sockets; it'll be important that anything we decide
* to get rid of here but don't immediately close get counted as moribund
* on subsequent invocations so we don't try to kill too many things if
* this gets called multiple times.
*/
/* TODO pick what to try to close */
}
}
/** Log how many bytes are used by buffers of different kinds and sizes. */
void
connection_dump_buffer_mem_stats(int severity)

View File

@ -247,6 +247,8 @@ void clock_skew_warning(const connection_t *conn, long apparent_skew,
int trusted, log_domain_mask_t domain,
const char *received, const char *source);
void connection_handle_oos(int n_socks, int failed);
#ifdef CONNECTION_PRIVATE
STATIC void connection_free_(connection_t *conn);