Author: andre
Date: Mon Oct 10 18:26:23 2011
New Revision: 226228
URL: http://svn.freebsd.org/changeset/base/226228
Log:
MFC r226113:
Prevent TCP sessions from stalling indefinitely in reassembly
when reaching the zone limit of reassembly queue entries.
Approved by: re (kib)
Modified:
stable/9/sys/netinet/tcp_reass.c
Directory Properties:
stable/9/sys/ (props changed)
stable/9/sys/amd64/include/xen/ (props changed)
stable/9/sys/boot/ (props changed)
stable/9/sys/boot/i386/efi/ (props changed)
stable/9/sys/boot/ia64/efi/ (props changed)
stable/9/sys/boot/ia64/ski/ (props changed)
stable/9/sys/boot/powerpc/boot1.chrp/ (props changed)
stable/9/sys/boot/powerpc/ofw/ (props changed)
stable/9/sys/cddl/contrib/opensolaris/ (props changed)
stable/9/sys/conf/ (props changed)
stable/9/sys/contrib/dev/acpica/ (props changed)
stable/9/sys/contrib/octeon-sdk/ (props changed)
stable/9/sys/contrib/pf/ (props changed)
stable/9/sys/contrib/x86emu/ (props changed)
Modified: stable/9/sys/netinet/tcp_reass.c
==============================================================================
--- stable/9/sys/netinet/tcp_reass.c Mon Oct 10 18:20:36 2011
(r226227)
+++ stable/9/sys/netinet/tcp_reass.c Mon Oct 10 18:26:23 2011
(r226228)
@@ -177,7 +177,9 @@ tcp_reass(struct tcpcb *tp, struct tcphd
struct tseg_qent *nq;
struct tseg_qent *te = NULL;
struct socket *so = tp->t_inpcb->inp_socket;
+ char *s = NULL;
int flags;
+ struct tseg_qent tqs;
INP_WLOCK_ASSERT(tp->t_inpcb);
@@ -215,19 +217,40 @@ tcp_reass(struct tcpcb *tp, struct tcphd
TCPSTAT_INC(tcps_rcvmemdrop);
m_freem(m);
*tlenp = 0;
+ if ((s = tcp_log_addrs(&tp->t_inpcb->inp_inc, th, NULL, NULL)))
{
+ log(LOG_DEBUG, "%s; %s: queue limit reached, "
+ "segment dropped\n", s, __func__);
+ free(s, M_TCPLOG);
+ }
return (0);
}
/*
* Allocate a new queue entry. If we can't, or hit the zone limit
* just drop the pkt.
+ *
+ * Use a temporary structure on the stack for the missing segment
+ * when the zone is exhausted. Otherwise we may get stuck.
*/
te = uma_zalloc(V_tcp_reass_zone, M_NOWAIT);
- if (te == NULL) {
+ if (te == NULL && th->th_seq != tp->rcv_nxt) {
TCPSTAT_INC(tcps_rcvmemdrop);
m_freem(m);
*tlenp = 0;
+ if ((s = tcp_log_addrs(&tp->t_inpcb->inp_inc, th, NULL, NULL)))
{
+ log(LOG_DEBUG, "%s; %s: global zone limit reached, "
+ "segment dropped\n", s, __func__);
+ free(s, M_TCPLOG);
+ }
return (0);
+ } else if (th->th_seq == tp->rcv_nxt) {
+ bzero(&tqs, sizeof(struct tseg_qent));
+ te = &tqs;
+ if ((s = tcp_log_addrs(&tp->t_inpcb->inp_inc, th, NULL, NULL)))
{
+ log(LOG_DEBUG, "%s; %s: global zone limit reached, "
+ "using stack for missing segment\n", s, __func__);
+ free(s, M_TCPLOG);
+ }
}
tp->t_segqlen++;
@@ -304,6 +327,8 @@ tcp_reass(struct tcpcb *tp, struct tcphd
if (p == NULL) {
LIST_INSERT_HEAD(&tp->t_segq, te, tqe_q);
} else {
+ KASSERT(te != &tqs, ("%s: temporary stack based entry not "
+ "first element in queue", __func__));
LIST_INSERT_AFTER(p, te, tqe_q);
}
@@ -327,7 +352,8 @@ present:
m_freem(q->tqe_m);
else
sbappendstream_locked(&so->so_rcv, q->tqe_m);
- uma_zfree(V_tcp_reass_zone, q);
+ if (q != &tqs)
+ uma_zfree(V_tcp_reass_zone, q);
tp->t_segqlen--;
q = nq;
} while (q && q->tqe_th->th_seq == tp->rcv_nxt);
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