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Lock ip forwarding route cache. While we're at it, remove the global

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variable ipforward_rt by introducing an ip_forward_cacheinval() call
to use to invalidate the cache.

Supported by:	FreeBSD Foundation
This commit is contained in:
sam 2003-10-14 19:19:12 +00:00
parent 5daf1cdd10
commit 5355d8b454
3 changed files with 95 additions and 37 deletions
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9
sys/netinet/in_rmx.c
View File

@ -141,13 +141,10 @@ in_addroute(void *v_arg, void *n_arg, struct radix_node_head *head,
/*
* If the new route created successfully, and we are forwarding,
* and there is a cached route, free it. Otherwise, we may end
* up using the wrong route.
* flush any cached routes to avoid using a stale value.
*/
if (ret != NULL && ipforwarding && ipforward_rt.ro_rt) {
RTFREE(ipforward_rt.ro_rt);
ipforward_rt.ro_rt = 0;
}
if (ret != NULL && ipforwarding)
ip_forward_cacheinval();
return ret;
}

121
sys/netinet/ip_input.c
View File

@ -212,6 +212,40 @@ int fw_one_pass = 1;
/* Dummynet hooks */
ip_dn_io_t *ip_dn_io_ptr;
/*
* One deep route cache for ip forwarding.
*/
static struct rtcache {
struct route rc_ro; /* most recently used route */
struct mtx rc_mtx; /* update lock for cache */
} ip_fwdcache;
#define RTCACHE_LOCK() mtx_lock(&ip_fwdcache.rc_mtx)
#define RTCACHE_UNLOCK() mtx_unlock(&ip_fwdcache.rc_mtx)
#define RTCACHE_LOCK_INIT() \
mtx_init(&ip_fwdcache.rc_mtx, "route cache", NULL, MTX_DEF);
#define RTCACHE_LOCK_ASSERT() mtx_assert(&ip_fwdcache.rc_mtx, MA_OWNED)
/*
* Get the current route cache contents.
*/
#define RTCACHE_GET(_ro) do { \
RTCACHE_LOCK(); \
*(_ro) = ip_fwdcache.rc_ro; \
RTCACHE_UNLOCK(); \
} while (0);
/*
* Update the cache contents. We optimize this using
* the routing table reference. XXX is this safe?
*/
#define RTCACHE_UPDATE(_ro) do { \
if ((_ro)->ro_rt != ip_fwdcache.rc_ro.ro_rt) { \
RTCACHE_LOCK(); \
ip_fwdcache.rc_ro = *(_ro); \
RTCACHE_UNLOCK(); \
} \
} while (0);
/*
* XXX this is ugly -- the following two global variables are
@ -237,7 +271,7 @@ static struct ip_srcrt {
static void save_rte(u_char *, struct in_addr);
static int ip_dooptions(struct mbuf *m, int,
struct sockaddr_in *next_hop);
static void ip_forward(struct mbuf *m, int srcrt,
static void ip_forward(struct mbuf *m, struct route *, int srcrt,
struct sockaddr_in *next_hop);
static void ip_freef(struct ipqhead *, struct ipq *);
static struct mbuf *ip_reass(struct mbuf *, struct ipqhead *,
@ -278,6 +312,9 @@ ip_init()
for (i = 0; i < IPREASS_NHASH; i++)
TAILQ_INIT(&ipq[i]);
bzero(&ip_fwdcache, sizeof(ip_fwdcache));
RTCACHE_LOCK_INIT();
maxnipq = nmbclusters / 32;
maxfragsperpacket = 16;
@ -290,11 +327,21 @@ ip_init()
}
/*
* XXX watch out this one. It is perhaps used as a cache for
* the most recently used route ? it is cleared in in_addroute()
* when a new route is successfully created.
* Invalidate any cached route used for forwarding.
*/
struct route ipforward_rt;
void
ip_forward_cacheinval(void)
{
struct rtentry *rt = NULL;
RTCACHE_LOCK();
rt = ip_fwdcache.rc_ro.ro_rt;
ip_fwdcache.rc_ro.ro_rt = 0;
RTCACHE_UNLOCK();
if (rt != NULL)
RTFREE(rt);
}
/*
* Ip input routine. Checksum and byte swap header. If fragmented
@ -312,6 +359,7 @@ ip_input(struct mbuf *m)
struct in_addr pkt_dst;
u_int32_t divert_info = 0; /* packet divert/tee info */
struct ip_fw_args args;
struct route cro; /* copy of cached route */
#ifdef FAST_IPSEC
struct m_tag *mtag;
struct tdb_ident *tdbi;
@ -710,7 +758,8 @@ pass:
goto bad;
}
#endif /* FAST_IPSEC */
ip_forward(m, 0, args.next_hop);
RTCACHE_GET(&cro);
ip_forward(m, &cro, 0, args.next_hop);
}
return;
@ -1308,6 +1357,14 @@ ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop)
struct in_addr *sin, dst;
n_time ntime;
struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET };
struct route cro; /* copy of cached route */
/*
* Grab a copy of the route cache in case we need
* to update to reflect source routing or the like.
* Could optimize this to do it later...
*/
RTCACHE_GET(&cro);
dst = ip->ip_dst;
cp = (u_char *)(ip + 1);
@ -1427,7 +1484,7 @@ dropit:
if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0)
ia = (INA)ifa_ifwithnet((SA)&ipaddr);
} else
ia = ip_rtaddr(ipaddr.sin_addr, &ipforward_rt);
ia = ip_rtaddr(ipaddr.sin_addr, &cro);
if (ia == 0) {
type = ICMP_UNREACH;
code = ICMP_UNREACH_SRCFAIL;
@ -1469,8 +1526,7 @@ dropit:
* use the incoming interface (should be same).
*/
if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 &&
(ia = ip_rtaddr(ipaddr.sin_addr,
&ipforward_rt)) == 0) {
(ia = ip_rtaddr(ipaddr.sin_addr, &cro)) == 0) {
type = ICMP_UNREACH;
code = ICMP_UNREACH_HOST;
goto bad;
@ -1550,7 +1606,7 @@ dropit:
}
}
if (forward && ipforwarding) {
ip_forward(m, 1, next_hop);
ip_forward(m, &cro, 1, next_hop);
return (1);
}
return (0);
@ -1735,7 +1791,8 @@ u_char inetctlerrmap[PRC_NCMDS] = {
* via a source route.
*/
static void
ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop)
ip_forward(struct mbuf *m, struct route *ro,
int srcrt, struct sockaddr_in *next_hop)
{
struct ip *ip = mtod(m, struct ip *);
struct rtentry *rt;
@ -1780,11 +1837,11 @@ ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop)
}
#endif
if (ip_rtaddr(pkt_dst, &ipforward_rt) == 0) {
if (ip_rtaddr(pkt_dst, ro) == 0) {
icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0);
return;
} else
rt = ipforward_rt.ro_rt;
rt = ro->ro_rt;
/*
* Save the IP header and at most 8 bytes of the payload,
@ -1874,9 +1931,13 @@ ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop)
tag.mh_next = m;
m = (struct mbuf *)&tag;
}
error = ip_output(m, (struct mbuf *)0, &ipforward_rt,
IP_FORWARDING, 0, NULL);
error = ip_output(m, (struct mbuf *)0, ro, IP_FORWARDING, 0, NULL);
}
/*
* Update the ip forwarding cache with the route we used.
* We may want to do this more selectively; not sure.
*/
RTCACHE_UPDATE(ro);
if (error)
ipstat.ips_cantforward++;
else {
@ -1885,7 +1946,7 @@ ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop)
ipstat.ips_redirectsent++;
else {
if (mcopy) {
ipflow_create(&ipforward_rt, mcopy);
ipflow_create(ro, mcopy);
m_freem(mcopy);
}
return;
@ -1920,11 +1981,10 @@ ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop)
* tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
* XXX quickhack!!!
*/
if (ipforward_rt.ro_rt) {
if (ro->ro_rt) {
struct secpolicy *sp = NULL;
int ipsecerror;
int ipsechdr;
struct route *ro;
sp = ipsec4_getpolicybyaddr(mcopy,
IPSEC_DIR_OUTBOUND,
@ -1932,7 +1992,7 @@ ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop)
&ipsecerror);
if (sp == NULL)
destifp = ipforward_rt.ro_rt->rt_ifp;
destifp = ro->ro_rt->rt_ifp;
else {
/* count IPsec header size */
ipsechdr = ipsec4_hdrsiz(mcopy,
@ -1952,10 +2012,11 @@ ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop)
if (sp->req != NULL
&& sp->req->sav != NULL
&& sp->req->sav->sah != NULL) {
ro = &sp->req->sav->sah->sa_route;
if (ro->ro_rt && ro->ro_rt->rt_ifp) {
struct route *saro;
saro = &sp->req->sav->sah->sa_route;
if (saro->ro_rt && saro->ro_rt->rt_ifp) {
dummyifp.if_mtu =
ro->ro_rt->rt_ifp->if_mtu;
saro->ro_rt->rt_ifp->if_mtu;
dummyifp.if_mtu -= ipsechdr;
destifp = &dummyifp;
}
@ -1971,11 +2032,10 @@ ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop)
* tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
* XXX quickhack!!!
*/
if (ipforward_rt.ro_rt) {
if (ro->ro_rt) {
struct secpolicy *sp = NULL;
int ipsecerror;
int ipsechdr;
struct route *ro;
sp = ipsec_getpolicybyaddr(mcopy,
IPSEC_DIR_OUTBOUND,
@ -1983,7 +2043,7 @@ ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop)
&ipsecerror);
if (sp == NULL)
destifp = ipforward_rt.ro_rt->rt_ifp;
destifp = ro->ro_rt->rt_ifp;
else {
/* count IPsec header size */
ipsechdr = ipsec4_hdrsiz(mcopy,
@ -2003,10 +2063,11 @@ ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop)
if (sp->req != NULL
&& sp->req->sav != NULL
&& sp->req->sav->sah != NULL) {
ro = &sp->req->sav->sah->sa_route;
if (ro->ro_rt && ro->ro_rt->rt_ifp) {
struct route *saro;
saro = &sp->req->sav->sah->sa_route;
if (saro->ro_rt && saro->ro_rt->rt_ifp) {
dummyifp.if_mtu =
ro->ro_rt->rt_ifp->if_mtu;
saro->ro_rt->rt_ifp->if_mtu;
dummyifp.if_mtu -= ipsechdr;
destifp = &dummyifp;
}
@ -2016,8 +2077,8 @@ ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop)
}
}
#else /* !IPSEC && !FAST_IPSEC */
if (ipforward_rt.ro_rt)
destifp = ipforward_rt.ro_rt->rt_ifp;
if (ro->ro_rt)
destifp = ro->ro_rt->rt_ifp;
#endif /*IPSEC*/
ipstat.ips_cantfrag++;
break;

2
sys/netinet/ip_var.h
View File

@ -154,7 +154,6 @@ extern u_short ip_id; /* ip packet ctr, for ids */
#endif
extern int ip_defttl; /* default IP ttl */
extern int ipforwarding; /* ip forwarding */
extern struct route ipforward_rt; /* ip forwarding cached route */
extern u_char ip_protox[];
extern struct socket *ip_rsvpd; /* reservation protocol daemon */
extern struct socket *ip_mrouter; /* multicast routing daemon */
@ -167,6 +166,7 @@ int ip_ctloutput(struct socket *, struct sockopt *sopt);
void ip_drain(void);
int ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu,
u_long if_hwassist_flags, int sw_csum);
void ip_forward_cacheinval(void);
void ip_freemoptions(struct ip_moptions *);
void ip_init(void);
extern int (*ip_mforward)(struct ip *, struct ifnet *, struct mbuf *,