fib: RCU conversion of fib_lookup()

[linux-2.6-block.git] / net / ipv4 / route.c

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 04e0df82b88cde2573fe30e380a1c5d0ec50f0da..7864d0c489683e985a1a900b66ad1635557dfbbe 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1773,12 +1773,15 @@ void ip_rt_get_source(u8 *addr, struct rtable *rt)
 
        if (rt->fl.iif == 0)
                src = rt->rt_src;
-       else if (fib_lookup(dev_net(rt->dst.dev), &rt->fl, &res) == 0) {
-               src = FIB_RES_PREFSRC(res);
-               fib_res_put(&res);
-       } else
-               src = inet_select_addr(rt->dst.dev, rt->rt_gateway,
+       else {
+               rcu_read_lock();
+               if (fib_lookup(dev_net(rt->dst.dev), &rt->fl, &res) == 0)
+                       src = FIB_RES_PREFSRC(res);
+               else
+                       src = inet_select_addr(rt->dst.dev, rt->rt_gateway,
                                        RT_SCOPE_UNIVERSE);
+               rcu_read_unlock();
+       }
        memcpy(addr, &src, 4);
 }
 
@@ -2081,6 +2084,7 @@ static int ip_mkroute_input(struct sk_buff *skb,
  *     Such approach solves two big problems:
  *     1. Not simplex devices are handled properly.
  *     2. IP spoofing attempts are filtered with 100% of guarantee.
+ *     called with rcu_read_lock()
  */
 
 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
@@ -2102,7 +2106,6 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
        unsigned        hash;
        __be32          spec_dst;
        int             err = -EINVAL;
-       int             free_res = 0;
        struct net    * net = dev_net(dev);
 
        /* IP on this device is disabled. */
@@ -2134,12 +2137,12 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
        /*
         *      Now we are ready to route packet.
         */
-       if ((err = fib_lookup(net, &fl, &res)) != 0) {
+       err = fib_lookup(net, &fl, &res);
+       if (err != 0) {
                if (!IN_DEV_FORWARD(in_dev))
                        goto e_hostunreach;
                goto no_route;
        }
-       free_res = 1;
 
        RT_CACHE_STAT_INC(in_slow_tot);
 
@@ -2148,8 +2151,8 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 
        if (res.type == RTN_LOCAL) {
                err = fib_validate_source(saddr, daddr, tos,
-                                            net->loopback_dev->ifindex,
-                                            dev, &spec_dst, &itag, skb->mark);
+                                         net->loopback_dev->ifindex,
+                                         dev, &spec_dst, &itag, skb->mark);
                if (err < 0)
                        goto martian_source_keep_err;
                if (err)
@@ -2164,9 +2167,6 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
                goto martian_destination;
 
        err = ip_mkroute_input(skb, &res, &fl, in_dev, daddr, saddr, tos);
-done:
-       if (free_res)
-               fib_res_put(&res);
 out:   return err;
 
 brd_input:
@@ -2226,7 +2226,7 @@ local_input:
        rth->rt_type    = res.type;
        hash = rt_hash(daddr, saddr, fl.iif, rt_genid(net));
        err = rt_intern_hash(hash, rth, NULL, skb, fl.iif);
-       goto done;
+       goto out;
 
 no_route:
        RT_CACHE_STAT_INC(in_no_route);
@@ -2249,21 +2249,21 @@ martian_destination:
 
 e_hostunreach:
        err = -EHOSTUNREACH;
-       goto done;
+       goto out;
 
 e_inval:
        err = -EINVAL;
-       goto done;
+       goto out;
 
 e_nobufs:
        err = -ENOBUFS;
-       goto done;
+       goto out;
 
 martian_source:
        err = -EINVAL;
 martian_source_keep_err:
        ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
-       goto done;
+       goto out;
 }
 
 int ip_route_input_common(struct sk_buff *skb, __be32 daddr, __be32 saddr,
@@ -2349,6 +2349,7 @@ skip_cache:
 }
 EXPORT_SYMBOL(ip_route_input_common);
 
+/* called with rcu_read_lock() */
 static int __mkroute_output(struct rtable **result,
                            struct fib_result *res,
                            const struct flowi *fl,
@@ -2373,18 +2374,13 @@ static int __mkroute_output(struct rtable **result,
        if (dev_out->flags & IFF_LOOPBACK)
                flags |= RTCF_LOCAL;
 
-       rcu_read_lock();
        in_dev = __in_dev_get_rcu(dev_out);
-       if (!in_dev) {
-               rcu_read_unlock();
+       if (!in_dev)
                return -EINVAL;
-       }
+
        if (res->type == RTN_BROADCAST) {
                flags |= RTCF_BROADCAST | RTCF_LOCAL;
-               if (res->fi) {
-                       fib_info_put(res->fi);
-                       res->fi = NULL;
-               }
+               res->fi = NULL;
        } else if (res->type == RTN_MULTICAST) {
                flags |= RTCF_MULTICAST | RTCF_LOCAL;
                if (!ip_check_mc(in_dev, oldflp->fl4_dst, oldflp->fl4_src,
@@ -2394,10 +2390,8 @@ static int __mkroute_output(struct rtable **result,
                 * default one, but do not gateway in this case.
                 * Yes, it is hack.
                 */
-               if (res->fi && res->prefixlen < 4) {
-                       fib_info_put(res->fi);
+               if (res->fi && res->prefixlen < 4)
                        res->fi = NULL;
-               }
        }
 
 
@@ -2467,6 +2461,7 @@ static int __mkroute_output(struct rtable **result,
        return 0;
 }
 
+/* called with rcu_read_lock() */
 static int ip_mkroute_output(struct rtable **rp,
                             struct fib_result *res,
                             const struct flowi *fl,
@@ -2509,7 +2504,6 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp,
        struct fib_result res;
        unsigned int flags = 0;
        struct net_device *dev_out = NULL;
-       int free_res = 0;
        int err;
 
 
@@ -2636,15 +2630,12 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp,
                err = -ENETUNREACH;
                goto out;
        }
-       free_res = 1;
 
        if (res.type == RTN_LOCAL) {
                if (!fl.fl4_src)
                        fl.fl4_src = fl.fl4_dst;
                dev_out = net->loopback_dev;
                fl.oif = dev_out->ifindex;
-               if (res.fi)
-                       fib_info_put(res.fi);
                res.fi = NULL;
                flags |= RTCF_LOCAL;
                goto make_route;
@@ -2668,8 +2659,6 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp,
 make_route:
        err = ip_mkroute_output(rp, &res, &fl, oldflp, dev_out, flags);
 
-       if (free_res)
-               fib_res_put(&res);
 out:   return err;
 }