diff mbox

[v6] ipv6: fix problem with expired dst cache

Message ID 1333707190-14075-1-git-send-email-gaofeng@cn.fujitsu.com
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Gao feng April 6, 2012, 10:13 a.m. UTC 
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>
---
 include/net/dst.h     |    6 +++-
 include/net/ip6_fib.h |   42 +++++++++++++++++++++++++++++
 net/ipv6/addrconf.c   |    9 ++----
 net/ipv6/ip6_fib.c    |    9 +++---
 net/ipv6/ndisc.c      |    3 +-
 net/ipv6/route.c      |   71 ++++++++++++++++++++++++++++++------------------
 6 files changed, 99 insertions(+), 41 deletions(-)

Comments

David Miller April 13, 2012, 4:58 p.m. UTC | #1 
From: Gao feng <gaofeng@cn.fujitsu.com>
Date: Fri, 6 Apr 2012 18:13:10 +0800

> 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>

Applied, thanks for doing this work.
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diff mbox

Patch

diff --git a/include/net/dst.h b/include/net/dst.h
index 59c5d18..ff4da42 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -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
diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index b26bb81..c64778f 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -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;
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 6a3bb60..7d5cb97 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -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;
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 5b27fbc..dbf6c10 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -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;
 			}
 		}
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 3dcdb81..176b469 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -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)
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 3992e26..27068be 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -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