ipv6: fix problem with expired dst cache
authorGao feng <gaofeng@cn.fujitsu.com>
Fri, 6 Apr 2012 00:13:10 +0000 (00:13 +0000)
committerDavid S. Miller <davem@davemloft.net>
Fri, 13 Apr 2012 16:58:29 +0000 (12:58 -0400)
If the ipv6 dst cache which copy from the dst generated by ICMPV6 RA packet.
this dst cache will not check expire because it has no RTF_EXPIRES flag.
So this dst cache will always be used until the dst gc run.

Change the struct dst_entry,add a union contains new pointer from and expires.
When rt6_info.rt6i_flags has no RTF_EXPIRES flag,the dst.expires has no use.
we can use this field to point to where the dst cache copy from.
The dst.from is only used in IPV6.

rt6_check_expired check if rt6_info.dst.from is expired.

ip6_rt_copy only set dst.from when the ort has flag RTF_ADDRCONF
and RTF_DEFAULT.then hold the ort.

ip6_dst_destroy release the ort.

Add some functions to operate the RTF_EXPIRES flag and expires(from) together.
and change the code to use these new adding functions.

Changes from v5:
modify ip6_route_add and ndisc_router_discovery to use new adding functions.

Only set dst.from when the ort has flag RTF_ADDRCONF
and RTF_DEFAULT.then hold the ort.

Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
include/net/dst.h
include/net/ip6_fib.h
net/ipv6/addrconf.c
net/ipv6/ip6_fib.c
net/ipv6/ndisc.c
net/ipv6/route.c

index 59c5d18cc3857da85690627b085e1065eeeb78ad..ff4da42fcfc6e1440e5bc5aca3ffffdb376d2a18 100644 (file)
@@ -36,7 +36,11 @@ struct dst_entry {
        struct net_device       *dev;
        struct  dst_ops         *ops;
        unsigned long           _metrics;
-       unsigned long           expires;
+       union {
+               unsigned long           expires;
+               /* point to where the dst_entry copied from */
+               struct dst_entry        *from;
+       };
        struct dst_entry        *path;
        struct neighbour __rcu  *_neighbour;
 #ifdef CONFIG_XFRM
index b26bb810198169c9b0d10462c282d284a6ad1bca..c64778fd5e135a7222518be0ebc3b018b8154d02 100644 (file)
@@ -123,6 +123,48 @@ static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst)
        return ((struct rt6_info *)dst)->rt6i_idev;
 }
 
+static inline void rt6_clean_expires(struct rt6_info *rt)
+{
+       if (!(rt->rt6i_flags & RTF_EXPIRES) && rt->dst.from)
+               dst_release(rt->dst.from);
+
+       rt->rt6i_flags &= ~RTF_EXPIRES;
+       rt->dst.expires = 0;
+}
+
+static inline void rt6_set_expires(struct rt6_info *rt, unsigned long expires)
+{
+       if (!(rt->rt6i_flags & RTF_EXPIRES) && rt->dst.from)
+               dst_release(rt->dst.from);
+
+       rt->rt6i_flags |= RTF_EXPIRES;
+       rt->dst.expires = expires;
+}
+
+static inline void rt6_update_expires(struct rt6_info *rt, int timeout)
+{
+       if (!(rt->rt6i_flags & RTF_EXPIRES) && rt->dst.from)
+               dst_release(rt->dst.from);
+
+       dst_set_expires(&rt->dst, timeout);
+       rt->rt6i_flags |= RTF_EXPIRES;
+}
+
+static inline void rt6_set_from(struct rt6_info *rt, struct rt6_info *from)
+{
+       struct dst_entry *new = (struct dst_entry *) from;
+
+       if (!(rt->rt6i_flags & RTF_EXPIRES) && rt->dst.from) {
+               if (new == rt->dst.from)
+                       return;
+               dst_release(rt->dst.from);
+       }
+
+       rt->rt6i_flags &= ~RTF_EXPIRES;
+       rt->dst.from = new;
+       dst_hold(new);
+}
+
 struct fib6_walker_t {
        struct list_head lh;
        struct fib6_node *root, *node;
index 6a3bb6077e19715bf2732bbce3d1c09d06aed104..7d5cb975cc6f8e6c22581daaa638b6b3df5a52d2 100644 (file)
@@ -803,8 +803,7 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp)
                                ip6_del_rt(rt);
                                rt = NULL;
                        } else if (!(rt->rt6i_flags & RTF_EXPIRES)) {
-                               rt->dst.expires = expires;
-                               rt->rt6i_flags |= RTF_EXPIRES;
+                               rt6_set_expires(rt, expires);
                        }
                }
                dst_release(&rt->dst);
@@ -1887,11 +1886,9 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)
                                rt = NULL;
                        } else if (addrconf_finite_timeout(rt_expires)) {
                                /* not infinity */
-                               rt->dst.expires = jiffies + rt_expires;
-                               rt->rt6i_flags |= RTF_EXPIRES;
+                               rt6_set_expires(rt, jiffies + rt_expires);
                        } else {
-                               rt->rt6i_flags &= ~RTF_EXPIRES;
-                               rt->dst.expires = 0;
+                               rt6_clean_expires(rt);
                        }
                } else if (valid_lft) {
                        clock_t expires = 0;
index 5b27fbcae346677a28db262c5ffc1a272e1b1cd5..93717435013e0a146c10bc8cf3ea4cbddb627f9b 100644 (file)
@@ -673,11 +673,10 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
                                            &rt->rt6i_gateway)) {
                                if (!(iter->rt6i_flags & RTF_EXPIRES))
                                        return -EEXIST;
-                               iter->dst.expires = rt->dst.expires;
-                               if (!(rt->rt6i_flags & RTF_EXPIRES)) {
-                                       iter->rt6i_flags &= ~RTF_EXPIRES;
-                                       iter->dst.expires = 0;
-                               }
+                               if (!(rt->rt6i_flags & RTF_EXPIRES))
+                                       rt6_clean_expires(iter);
+                               else
+                                       rt6_set_expires(iter, rt->dst.expires);
                                return -EEXIST;
                        }
                }
index 3dcdb81ec3e8abdb934627cd243aed0e5ce3b5a3..176b469322acd0b63b6e8d7ad0f095129b165868 100644 (file)
@@ -1264,8 +1264,7 @@ static void ndisc_router_discovery(struct sk_buff *skb)
        }
 
        if (rt)
-               rt->dst.expires = jiffies + (HZ * lifetime);
-
+               rt6_set_expires(rt, jiffies + (HZ * lifetime));
        if (ra_msg->icmph.icmp6_hop_limit) {
                in6_dev->cnf.hop_limit = ra_msg->icmph.icmp6_hop_limit;
                if (rt)
index 3992e26a603987cf8bba458dd4f687af5c900a2f..bc4888d902b2ed904f0ca767ac3e4d9cd35c252c 100644 (file)
@@ -62,7 +62,7 @@
 #include <linux/sysctl.h>
 #endif
 
-static struct rt6_info *ip6_rt_copy(const struct rt6_info *ort,
+static struct rt6_info *ip6_rt_copy(struct rt6_info *ort,
                                    const struct in6_addr *dest);
 static struct dst_entry        *ip6_dst_check(struct dst_entry *dst, u32 cookie);
 static unsigned int     ip6_default_advmss(const struct dst_entry *dst);
@@ -285,6 +285,10 @@ static void ip6_dst_destroy(struct dst_entry *dst)
                rt->rt6i_idev = NULL;
                in6_dev_put(idev);
        }
+
+       if (!(rt->rt6i_flags & RTF_EXPIRES) && dst->from)
+               dst_release(dst->from);
+
        if (peer) {
                rt->rt6i_peer = NULL;
                inet_putpeer(peer);
@@ -329,8 +333,17 @@ static void ip6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 
 static __inline__ int rt6_check_expired(const struct rt6_info *rt)
 {
-       return (rt->rt6i_flags & RTF_EXPIRES) &&
-               time_after(jiffies, rt->dst.expires);
+       struct rt6_info *ort = NULL;
+
+       if (rt->rt6i_flags & RTF_EXPIRES) {
+               if (time_after(jiffies, rt->dst.expires))
+                       return 1;
+       } else if (rt->dst.from) {
+               ort = (struct rt6_info *) rt->dst.from;
+               return (ort->rt6i_flags & RTF_EXPIRES) &&
+                       time_after(jiffies, ort->dst.expires);
+       }
+       return 0;
 }
 
 static inline int rt6_need_strict(const struct in6_addr *daddr)
@@ -620,12 +633,11 @@ int rt6_route_rcv(struct net_device *dev, u8 *opt, int len,
                                 (rt->rt6i_flags & ~RTF_PREF_MASK) | RTF_PREF(pref);
 
        if (rt) {
-               if (!addrconf_finite_timeout(lifetime)) {
-                       rt->rt6i_flags &= ~RTF_EXPIRES;
-               } else {
-                       rt->dst.expires = jiffies + HZ * lifetime;
-                       rt->rt6i_flags |= RTF_EXPIRES;
-               }
+               if (!addrconf_finite_timeout(lifetime))
+                       rt6_clean_expires(rt);
+               else
+                       rt6_set_expires(rt, jiffies + HZ * lifetime);
+
                dst_release(&rt->dst);
        }
        return 0;
@@ -730,7 +742,7 @@ int ip6_ins_rt(struct rt6_info *rt)
        return __ip6_ins_rt(rt, &info);
 }
 
-static struct rt6_info *rt6_alloc_cow(const struct rt6_info *ort,
+static struct rt6_info *rt6_alloc_cow(struct rt6_info *ort,
                                      const struct in6_addr *daddr,
                                      const struct in6_addr *saddr)
 {
@@ -954,10 +966,10 @@ struct dst_entry *ip6_blackhole_route(struct net *net, struct dst_entry *dst_ori
                rt->rt6i_idev = ort->rt6i_idev;
                if (rt->rt6i_idev)
                        in6_dev_hold(rt->rt6i_idev);
-               rt->dst.expires = 0;
 
                rt->rt6i_gateway = ort->rt6i_gateway;
-               rt->rt6i_flags = ort->rt6i_flags & ~RTF_EXPIRES;
+               rt->rt6i_flags = ort->rt6i_flags;
+               rt6_clean_expires(rt);
                rt->rt6i_metric = 0;
 
                memcpy(&rt->rt6i_dst, &ort->rt6i_dst, sizeof(struct rt6key));
@@ -1019,10 +1031,9 @@ static void ip6_link_failure(struct sk_buff *skb)
 
        rt = (struct rt6_info *) skb_dst(skb);
        if (rt) {
-               if (rt->rt6i_flags & RTF_CACHE) {
-                       dst_set_expires(&rt->dst, 0);
-                       rt->rt6i_flags |= RTF_EXPIRES;
-               } else if (rt->rt6i_node && (rt->rt6i_flags & RTF_DEFAULT))
+               if (rt->rt6i_flags & RTF_CACHE)
+                       rt6_update_expires(rt, 0);
+               else if (rt->rt6i_node && (rt->rt6i_flags & RTF_DEFAULT))
                        rt->rt6i_node->fn_sernum = -1;
        }
 }
@@ -1289,9 +1300,12 @@ int ip6_route_add(struct fib6_config *cfg)
        }
 
        rt->dst.obsolete = -1;
-       rt->dst.expires = (cfg->fc_flags & RTF_EXPIRES) ?
-                               jiffies + clock_t_to_jiffies(cfg->fc_expires) :
-                               0;
+
+       if (cfg->fc_flags & RTF_EXPIRES)
+               rt6_set_expires(rt, jiffies +
+                               clock_t_to_jiffies(cfg->fc_expires));
+       else
+               rt6_clean_expires(rt);
 
        if (cfg->fc_protocol == RTPROT_UNSPEC)
                cfg->fc_protocol = RTPROT_BOOT;
@@ -1736,8 +1750,8 @@ again:
                        features |= RTAX_FEATURE_ALLFRAG;
                        dst_metric_set(&rt->dst, RTAX_FEATURES, features);
                }
-               dst_set_expires(&rt->dst, net->ipv6.sysctl.ip6_rt_mtu_expires);
-               rt->rt6i_flags |= RTF_MODIFIED|RTF_EXPIRES;
+               rt6_update_expires(rt, net->ipv6.sysctl.ip6_rt_mtu_expires);
+               rt->rt6i_flags |= RTF_MODIFIED;
                goto out;
        }
 
@@ -1765,9 +1779,8 @@ again:
                 * which is 10 mins. After 10 mins the decreased pmtu is expired
                 * and detecting PMTU increase will be automatically happened.
                 */
-               dst_set_expires(&nrt->dst, net->ipv6.sysctl.ip6_rt_mtu_expires);
-               nrt->rt6i_flags |= RTF_DYNAMIC|RTF_EXPIRES;
-
+               rt6_update_expires(nrt, net->ipv6.sysctl.ip6_rt_mtu_expires);
+               nrt->rt6i_flags |= RTF_DYNAMIC;
                ip6_ins_rt(nrt);
        }
 out:
@@ -1799,7 +1812,7 @@ void rt6_pmtu_discovery(const struct in6_addr *daddr, const struct in6_addr *sad
  *     Misc support functions
  */
 
-static struct rt6_info *ip6_rt_copy(const struct rt6_info *ort,
+static struct rt6_info *ip6_rt_copy(struct rt6_info *ort,
                                    const struct in6_addr *dest)
 {
        struct net *net = dev_net(ort->dst.dev);
@@ -1819,10 +1832,14 @@ static struct rt6_info *ip6_rt_copy(const struct rt6_info *ort,
                if (rt->rt6i_idev)
                        in6_dev_hold(rt->rt6i_idev);
                rt->dst.lastuse = jiffies;
-               rt->dst.expires = 0;
 
                rt->rt6i_gateway = ort->rt6i_gateway;
-               rt->rt6i_flags = ort->rt6i_flags & ~RTF_EXPIRES;
+               rt->rt6i_flags = ort->rt6i_flags;
+               if ((ort->rt6i_flags & (RTF_DEFAULT | RTF_ADDRCONF)) ==
+                   (RTF_DEFAULT | RTF_ADDRCONF))
+                       rt6_set_from(rt, ort);
+               else
+                       rt6_clean_expires(rt);
                rt->rt6i_metric = 0;
 
 #ifdef CONFIG_IPV6_SUBTREES