@@ -446,6 +446,28 @@ extern int sysctl_tcp_synack_retries;
EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
+/* Decide when to expire the request and when to resend SYN-ACK */
+static inline void syn_ack_recalc(struct request_sock *req, const int thresh,
+ const int max_retries,
+ const u8 rskq_defer_accept,
+ int *expire, int *resend)
+{
+ if (!rskq_defer_accept) {
+ *expire = req->retrans >= thresh;
+ *resend = 1;
+ return;
+ }
+ *expire = req->retrans >= thresh &&
+ (!inet_rsk(req)->acked || req->retrans >= max_retries);
+ /*
+ * Do not resend while waiting for data after ACK,
+ * start to resend on end of deferring period to give
+ * last chance for data or ACK to create established socket.
+ */
+ *resend = !inet_rsk(req)->acked ||
+ req->retrans >= rskq_defer_accept - 1;
+}
+
void inet_csk_reqsk_queue_prune(struct sock *parent,
const unsigned long interval,
const unsigned long timeout,
@@ -501,9 +523,15 @@ void inet_csk_reqsk_queue_prune(struct s
reqp=&lopt->syn_table[i];
while ((req = *reqp) != NULL) {
if (time_after_eq(now, req->expires)) {
- if ((req->retrans < thresh ||
- (inet_rsk(req)->acked && req->retrans < max_retries))
- && !req->rsk_ops->rtx_syn_ack(parent, req)) {
+ int expire = 0, resend = 0;
+
+ syn_ack_recalc(req, thresh, max_retries,
+ queue->rskq_defer_accept,
+ &expire, &resend);
+ if (!expire &&
+ (!resend ||
+ !req->rsk_ops->rtx_syn_ack(parent, req) ||
+ inet_rsk(req)->acked)) {
unsigned long timeo;
if (req->retrans++ == 0)
Change SYN-ACK retransmitting code for the TCP_DEFER_ACCEPT users to not retransmit SYN-ACKs during the deferring period if ACK from client was received. The goal is to reduce traffic during the deferring period. When the period is finished we continue with sending SYN-ACKs (at least one) but this time any traffic from client will change the request to established socket allowing application to terminate it properly. Also, do not drop acked request if sending of SYN-ACK fails. Signed-off-by: Julian Anastasov <ja@ssi.bg> --- -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html