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o Add syslog logging under LOG_DEBUG to various failures caused by

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bogus segments
o Add more KASSERT()s
o Update comments
This commit is contained in:
Andre Oppermann 2007-05-18 21:13:01 +00:00
parent eefc497257
commit 5df429a002
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=169685
1 changed files with 38 additions and 5 deletions
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43
sys/netinet/tcp_syncache.c
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@ -50,6 +50,7 @@
#include <sys/random.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/syslog.h>
#include <vm/uma.h>
@ -378,6 +379,7 @@ syncache_timer(void *xsch)
struct syncache_head *sch = (struct syncache_head *)xsch;
struct syncache *sc, *nsc;
int tick = ticks;
char *s;
/* NB: syncache_head has already been locked by the callout. */
SCH_LOCK_ASSERT(sch);
@ -398,6 +400,11 @@ syncache_timer(void *xsch)
}
if (sc->sc_rxmits > tcp_syncache.rexmt_limit) {
if ((s = tcp_log_addrs(&sc->sc_inc, NULL, NULL, NULL))) {
log(LOG_DEBUG, "%s; %s: Response timeout\n",
s, __func__);
free(s, M_TCPLOG);
}
syncache_drop(sc, sch);
tcpstat.tcps_sc_stale++;
continue;
@ -553,6 +560,7 @@ syncache_socket(struct syncache *sc, struct socket *lso, struct mbuf *m)
struct inpcb *inp = NULL;
struct socket *so;
struct tcpcb *tp;
char *s;
NET_ASSERT_GIANT();
INP_INFO_WLOCK_ASSERT(&tcbinfo);
@ -566,10 +574,17 @@ syncache_socket(struct syncache *sc, struct socket *lso, struct mbuf *m)
so = sonewconn(lso, SS_ISCONNECTED);
if (so == NULL) {
/*
* Drop the connection; we will send a RST if the peer
* retransmits the ACK,
* Drop the connection; we will either send a RST or
* have the peer retransmit its SYN again after its
* RTO and try again.
*/
tcpstat.tcps_listendrop++;
if ((s = tcp_log_addrs(&sc->sc_inc, NULL, NULL, NULL))) {
log(LOG_DEBUG, "%s; %s: Socket create failed "
"due to limits or memory shortage\n",
s, __func__);
free(s, M_TCPLOG);
}
goto abort2;
}
#ifdef MAC
@ -757,12 +772,15 @@ syncache_expand(struct in_conninfo *inc, struct tcpopt *to, struct tcphdr *th,
struct syncache *sc;
struct syncache_head *sch;
struct syncache scs;
char *s;
/*
* Global TCP locks are held because we manipulate the PCB lists
* and create a new socket.
*/
INP_INFO_WLOCK_ASSERT(&tcbinfo);
KASSERT((th->th_flags & (TH_RST|TH_ACK|TH_SYN)) == TH_ACK,
("%s: can handle only ACK", __func__));
sc = syncache_lookup(inc, &sch); /* returns locked sch */
SCH_LOCK_ASSERT(sch);
@ -778,13 +796,21 @@ syncache_expand(struct in_conninfo *inc, struct tcpopt *to, struct tcphdr *th,
*/
if (!tcp_syncookies) {
SCH_UNLOCK(sch);
if ((s = tcp_log_addrs(inc, th, NULL, NULL)))
log(LOG_DEBUG, "%s; %s: Spurious ACK\n",
s, __func__);
goto failed;
}
bzero(&scs, sizeof(scs));
sc = syncookie_lookup(inc, sch, &scs, to, th, *lsop);
SCH_UNLOCK(sch);
if (sc == NULL)
if (sc == NULL) {
if ((s = tcp_log_addrs(inc, th, NULL, NULL)))
log(LOG_DEBUG, "%s; %s: Segment failed "
"SYNCOOKIE authentication\n",
s, __func__);
goto failed;
}
tcpstat.tcps_sc_recvcookie++;
} else {
/* Pull out the entry to unlock the bucket row. */
@ -795,10 +821,15 @@ syncache_expand(struct in_conninfo *inc, struct tcpopt *to, struct tcphdr *th,
}
/*
* If seg contains an ACK, but not for our SYN/ACK, send a RST.
* Segment validation:
* ACK must match our initial sequence number + 1 (the SYN|ACK).
*/
if (th->th_ack != sc->sc_iss + 1)
if (th->th_ack != sc->sc_iss + 1) {
if ((s = tcp_log_addrs(inc, th, NULL, NULL)))
log(LOG_DEBUG, "%s; %s: ACK %u != ISS+1 %u\n",
s, __func__, th->th_ack, sc->sc_iss);
goto failed;
}
*lsop = syncache_socket(sc, *lsop, m);
@ -813,6 +844,8 @@ syncache_expand(struct in_conninfo *inc, struct tcpopt *to, struct tcphdr *th,
failed:
if (sc != NULL && sc != &scs)
syncache_free(sc);
if (s != NULL)
free(s, M_TCPLOG);
*lsop = NULL;
return (0);
}