doc/share/security/patches/SA-18:08/tcp-10.patch
2018-08-06 20:44:33 +00:00

58 lines
2.1 KiB
Diff

--- share/man/man4/tcp.4.orig
+++ share/man/man4/tcp.4
@@ -436,6 +436,20 @@
Reseeding should not be necessary, and will break
.Dv TIME_WAIT
recycling for a few minutes.
+.It Va reass.cursegments
+The current total number of segments present in all reassembly queues.
+.It Va reass.maxsegments
+The maximum limit on the total number of segments across all reassembly
+queues.
+The limit can be adjusted as a tunable.
+.It Va reass.maxqueuelen
+The maximum number of segments allowed in each reassembly queue.
+By default, the system chooses a limit based on each TCP connection's
+receive buffer size and maximum segment size (MSS).
+The actual limit applied to a session's reassembly queue will be the lower of
+the system-calculated automatic limit and the user-specified
+.Va reass.maxqueuelen
+limit.
.It Va rexmit_min , rexmit_slop
Adjust the retransmit timer calculation for
.Tn TCP .
--- sys/netinet/tcp_reass.c.orig
+++ sys/netinet/tcp_reass.c
@@ -96,6 +96,11 @@
static uma_zone_t tcp_reass_zone;
+static u_int tcp_reass_maxqueuelen = 100;
+SYSCTL_UINT(_net_inet_tcp_reass, OID_AUTO, maxqueuelen, CTLFLAG_RWTUN,
+ &tcp_reass_maxqueuelen, 0,
+ "Maximum number of TCP Segments per Reassembly Queue");
+
/* Initialize TCP reassembly queue */
static void
tcp_reass_zone_change(void *tag)
@@ -184,6 +189,10 @@
* socket receive buffer determines our advertised window and grows
* automatically when socket buffer autotuning is enabled. Use it as the
* basis for our queue limit.
+ *
+ * However, allow the user to specify a ceiling for the number of
+ * segments in each queue.
+ *
* Always let the missing segment through which caused this queue.
* NB: Access to the socket buffer is left intentionally unlocked as we
* can tolerate stale information here.
@@ -194,7 +203,8 @@
* is understood.
*/
if ((th->th_seq != tp->rcv_nxt || !TCPS_HAVEESTABLISHED(tp->t_state)) &&
- tp->t_segqlen >= (so->so_rcv.sb_hiwat / tp->t_maxseg) + 1) {
+ tp->t_segqlen >= min((so->so_rcv.sb_hiwat / tp->t_maxseg) + 1,
+ tcp_reass_maxqueuelen)) {
tcp_reass_overflows++;
TCPSTAT_INC(tcps_rcvmemdrop);
m_freem(m);