ipv4: Cache input routes in fib_info nexthops.

Caching input routes is slightly simpler than output routes, since we
don't need to be concerned with nexthop exceptions.  (locally
destined, and routed packets, never trigger PMTU events or redirects
that will be processed by us).

However, we have to elide caching for the DIRECTSRC and non-zero itag
cases.

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index fb62c590360ed289a4534f02fe01c6962308168f..e69c3a47153de4826fdbdd8a42d64a0bb2eed974 100644 (file)
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -82,6 +82,7 @@ struct fib_nh {
        __be32                  nh_saddr;
        int                     nh_saddr_genid;
        struct rtable           *nh_rth_output;
+       struct rtable           *nh_rth_input;
        struct fnhe_hash_bucket *nh_exceptions;
 };
 

diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 83d0f42b619a439bacd59b6173a86e100524a457..e55171f184f9731274c568345b9b74c14b2e63cc 100644 (file)
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -173,6 +173,8 @@ static void free_fib_info_rcu(struct rcu_head *head)
                        free_nh_exceptions(nexthop_nh);
                if (nexthop_nh->nh_rth_output)
                        dst_release(&nexthop_nh->nh_rth_output->dst);
+               if (nexthop_nh->nh_rth_input)
+                       dst_release(&nexthop_nh->nh_rth_input->dst);
        } endfor_nexthops(fi);
 
        release_net(fi->fib_net);

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 8a0260010ea1c30a212af73d43780a3deebcd4f1..97cca8a03d94a8c3a40c2f5d070d15131b1afb2f 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1231,6 +1231,9 @@ static void rt_cache_route(struct fib_nh *nh, struct rtable *rt)
 {
        struct rtable *orig, *prev, **p = &nh->nh_rth_output;
 
+       if (rt_is_input_route(rt))
+               p = &nh->nh_rth_input;
+
        orig = *p;
 
        prev = cmpxchg(p, orig, rt);
@@ -1241,6 +1244,11 @@ static void rt_cache_route(struct fib_nh *nh, struct rtable *rt)
        }
 }
 
+static bool rt_cache_valid(struct rtable *rt)
+{
+       return (rt && rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK);
+}
+
 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
                           const struct fib_result *res,
                           struct fib_nh_exception *fnhe,
@@ -1257,8 +1265,7 @@ static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
 #ifdef CONFIG_IP_ROUTE_CLASSID
                rt->dst.tclassid = nh->nh_tclassid;
 #endif
-               if (!(rt->dst.flags & DST_HOST) &&
-                   rt_is_output_route(rt))
+               if (!(rt->dst.flags & DST_HOST))
                        rt_cache_route(nh, rt);
        }
 
@@ -1384,11 +1391,11 @@ static int __mkroute_input(struct sk_buff *skb,
                           __be32 daddr, __be32 saddr, u32 tos,
                           struct rtable **result)
 {
-       struct fib_nh_exception *fnhe;
        struct rtable *rth;
        int err;
        struct in_device *out_dev;
        unsigned int flags = 0;
+       bool do_cache;
        u32 itag;
 
        /* get a working reference to the output device */
@@ -1431,13 +1438,21 @@ static int __mkroute_input(struct sk_buff *skb,
                }
        }
 
-       fnhe = NULL;
-       if (res->fi)
-               fnhe = find_exception(&FIB_RES_NH(*res), daddr);
+       do_cache = false;
+       if (res->fi) {
+               if (!(flags & RTCF_DIRECTSRC) && !itag) {
+                       rth = FIB_RES_NH(*res).nh_rth_input;
+                       if (rt_cache_valid(rth)) {
+                               dst_use(&rth->dst, jiffies);
+                               goto out;
+                       }
+                       do_cache = true;
+               }
+       }
 
        rth = rt_dst_alloc(out_dev->dev,
                           IN_DEV_CONF_GET(in_dev, NOPOLICY),
-                          IN_DEV_CONF_GET(out_dev, NOXFRM), false);
+                          IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
        if (!rth) {
                err = -ENOBUFS;
                goto cleanup;
@@ -1456,8 +1471,8 @@ static int __mkroute_input(struct sk_buff *skb,
        rth->dst.input = ip_forward;
        rth->dst.output = ip_output;
 
-       rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag);
-
+       rt_set_nexthop(rth, daddr, res, NULL, res->fi, res->type, itag);
+out:
        *result = rth;
        err = 0;
  cleanup:
@@ -1509,6 +1524,7 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
        struct rtable   *rth;
        int             err = -EINVAL;
        struct net    *net = dev_net(dev);
+       bool do_cache;
 
        /* IP on this device is disabled. */
 
@@ -1522,6 +1538,7 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
        if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
                goto martian_source;
 
+       res.fi = NULL;
        if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
                goto brd_input;
 
@@ -1597,8 +1614,20 @@ brd_input:
        RT_CACHE_STAT_INC(in_brd);
 
 local_input:
+       do_cache = false;
+       if (res.fi) {
+               if (!(flags & RTCF_DIRECTSRC) && !itag) {
+                       rth = FIB_RES_NH(res).nh_rth_input;
+                       if (rt_cache_valid(rth)) {
+                               dst_use(&rth->dst, jiffies);
+                               goto set_and_out;
+                       }
+                       do_cache = true;
+               }
+       }
+
        rth = rt_dst_alloc(net->loopback_dev,
-                          IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
+                          IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
        if (!rth)
                goto e_nobufs;
 
@@ -1622,6 +1651,9 @@ local_input:
                rth->dst.error= -err;
                rth->rt_flags   &= ~RTCF_LOCAL;
        }
+       if (do_cache)
+               rt_cache_route(&FIB_RES_NH(res), rth);
+set_and_out:
        skb_dst_set(skb, &rth->dst);
        err = 0;
        goto out;
@@ -1756,8 +1788,7 @@ static struct rtable *__mkroute_output(const struct fib_result *res,
                fnhe = find_exception(&FIB_RES_NH(*res), fl4->daddr);
                if (!fnhe) {
                        rth = FIB_RES_NH(*res).nh_rth_output;
-                       if (rth &&
-                           rth->dst.obsolete == DST_OBSOLETE_FORCE_CHK) {
+                       if (rt_cache_valid(rth)) {
                                dst_use(&rth->dst, jiffies);
                                return rth;
                        }