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o add locking to protect routing table refcnt manipulations

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o add some more debugging help for figuring out why folks are
  getting complaints about releasing routing table entries with
  a zero refcnt
o fix comment that talked about spl's
o remove duplicate define of DUMMYNET_DEBUG

Supported by:	FreeBSD Foundation
This commit is contained in:
Sam Leffler 2003-10-29 19:03:58 +00:00
parent 8dbc9c8bf4
commit 3520e9d61d
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=121699
1 changed files with 18 additions and 16 deletions
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34
sys/netinet/ip_dummynet.c
View File

@ -39,10 +39,7 @@
* + scheduler and dummynet functions;
* + configuration and initialization.
*
* NOTA BENE: critical sections are protected by splimp()/splx()
* pairs. One would think that splnet() is enough as for most of
* the netinet code, but it is not so because when used with
* bridging, dummynet is invoked at splimp().
* NOTA BENE: critical sections are protected by the "dummynet lock".
*
* Most important Changes:
*
@ -152,7 +149,6 @@ SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, red_max_pkt_size,
CTLFLAG_RD, &red_max_pkt_size, 0, "RED Max packet size");
#endif
#define DUMMYNET_DEBUG
#ifdef DUMMYNET_DEBUG
int dummynet_debug = 0;
#ifdef SYSCTL_NODE
@ -180,7 +176,7 @@ static struct mtx dummynet_mtx;
static int config_pipe(struct dn_pipe *p);
static int ip_dn_ctl(struct sockopt *sopt);
static void rt_unref(struct rtentry *);
static void rt_unref(struct rtentry *, const char *);
static void dummynet(void *);
static void dummynet_flush(void);
void dummynet_drain(void);
@ -190,14 +186,16 @@ static void dn_rule_delete(void *);
int if_tx_rdy(struct ifnet *ifp);
static void
rt_unref(struct rtentry *rt)
rt_unref(struct rtentry *rt, const char *where)
{
if (rt == NULL)
return ;
if (rt->rt_refcnt <= 0)
printf("dummynet: warning, refcnt now %ld, decreasing\n",
rt->rt_refcnt);
RTFREE(rt);
RT_LOCK(rt);
if (rt->rt_refcnt <= 0) {
printf("dummynet: warning, refcnt now %ld, decreasing (%s)\n",
rt->rt_refcnt, where);
}
RTFREE_LOCKED(rt);
}
/*
@ -452,7 +450,7 @@ transmit_event(struct dn_pipe *pipe)
switch (pkt->dn_dir) {
case DN_TO_IP_OUT:
(void)ip_output((struct mbuf *)pkt, NULL, NULL, 0, NULL, NULL);
rt_unref (pkt->ro.ro_rt) ;
rt_unref (pkt->ro.ro_rt, __func__) ;
break ;
case DN_TO_IP_IN :
@ -1198,11 +1196,15 @@ dummynet_io(struct mbuf *m, int pipe_nr, int dir, struct ip_fw_args *fwa)
* a pointer into *ro so it needs to be updated.
*/
pkt->ro = *(fwa->ro);
if (fwa->ro->ro_rt)
fwa->ro->ro_rt->rt_refcnt++ ;
if (pkt->ro.ro_rt) {
RT_LOCK(pkt->ro.ro_rt);
pkt->ro.ro_rt->rt_refcnt++ ;
KASSERT(pkt->ro.ro_rt->rt_refcnt > 0,
("bogus refcnt %ld", pkt->ro.ro_rt->rt_refcnt));
RT_UNLOCK(pkt->ro.ro_rt);
}
if (fwa->dst == (struct sockaddr_in *)&fwa->ro->ro_dst) /* dst points into ro */
fwa->dst = (struct sockaddr_in *)&(pkt->ro.ro_dst) ;
pkt->dn_dst = fwa->dst;
pkt->flags = fwa->flags;
}
@ -1303,7 +1305,7 @@ dummynet_io(struct mbuf *m, int pipe_nr, int dir, struct ip_fw_args *fwa)
*/
#define DN_FREE_PKT(pkt) { \
struct dn_pkt *n = pkt ; \
rt_unref ( n->ro.ro_rt ) ; \
rt_unref ( n->ro.ro_rt, __func__ ) ; \
m_freem(n->dn_m); \
pkt = DN_NEXT(n) ; \
free(n, M_DUMMYNET) ; }