@@ -476,7 +476,7 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
*/
if (!ctx || fallback) {
if (fallback_is_fatal)
- goto close_child;
+ goto dispose_child;
if (ctx) {
subflow_ulp_fallback(child, ctx);
@@ -506,11 +506,11 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
owner = mptcp_token_get_sock(ctx->token);
if (!owner)
- goto close_child;
+ goto dispose_child;
ctx->conn = (struct sock *)owner;
if (!mptcp_finish_join(child))
- goto close_child;
+ goto dispose_child;
SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKRX);
tcp_sk(child)->drop_req = true;
@@ -530,11 +530,14 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
!mptcp_subflow_ctx(child)->conn));
return child;
-close_child:
+dispose_child:
+ tcp_sk(child)->drop_req = true;
tcp_send_active_reset(child, GFP_ATOMIC);
- inet_csk_prepare_forced_close(child);
+ inet_csk_prepare_for_destroy_sock(child);
tcp_done(child);
- return NULL;
+
+ /* The last child reference will be released by the caller */
+ return child;
}
static struct inet_connection_sock_af_ops subflow_specific;
Currently, on MP_JOIN failure we reset the child socket, but leave the request socket untouched. tcp_check_req will deal with it according to the 'tcp_abort_on_overflow' sysctl value - by default the req socket will stay alive. The above leads to inconsistent behavior on MP JOIN failure, and bad listener overflow accounting. This patch addresses the issue leveraging the infrastructure just introduced to ask the TCP stack to drop the req on failure. The child socket is not freed anymore by subflow_syn_recv_sock(), instead it's moved to a dead state and will be disposed by the next sock_put done by the TCP stack, so that listener overflow accounting is not affected by MP JOIN failure. Reported-by: Christoph Paasch <cpaasch@apple.com> Fixes: f296234c98a8 ("mptcp: Add handling of incoming MP_JOIN requests") Signed-off-by: Paolo Abeni <pabeni@redhat.com> --- net/mptcp/subflow.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)