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Message-ID: <CAJFZqHy5B8dqJWXBN_hHBdf2=gYjyyjiok=B_3XqbuEEpST07A@mail.gmail.com>
Date: Tue, 6 Mar 2012 15:01:43 +0800
From: RongQing Li <roy.qing.li@...il.com>
To: Gao feng <gaofeng@...fujitsu.com>
Cc: davem@...emloft.net, netdev@...r.kernel.org, eric.dumazet@...il.com
Subject: Re: [PATCH v5] ipv6: Fix problem with expired dst cache
2012/3/5 Gao feng <gaofeng@...fujitsu.com>:
> 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.
>
> In func rt6_check_expired check if rt6_info.dst.from is expired.
>
> In func ip6_rt_copy only set dst.from when the ort has flag RTF_ADDRCONF
> and RTF_DEFAULT.then hold the ort.
>
> In func 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.
>
> Signed-off-by: Gao feng <gaofeng@...fujitsu.com>
> ---
> include/net/dst.h | 7 ++++++-
> include/net/ip6_fib.h | 42 ++++++++++++++++++++++++++++++++++++++++++
> net/ipv6/addrconf.c | 9 +++------
> net/ipv6/ip6_fib.c | 3 +--
> net/ipv6/route.c | 49 +++++++++++++++++++++++++++++++------------------
> 5 files changed, 83 insertions(+), 27 deletions(-)
>
> diff --git a/include/net/dst.h b/include/net/dst.h
> index 344c8dd..864cd18 100644
> --- a/include/net/dst.h
> +++ b/include/net/dst.h
> @@ -35,7 +35,12 @@ 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..07e578e 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;
> +}
> +
Calling dst_set_expires() in rt6_update_expires() will double release
rt->dst.from?
-Roy
> +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 c02280a..b5cb3b1 100644
> --- a/net/ipv6/addrconf.c
> +++ b/net/ipv6/addrconf.c
> @@ -799,8 +799,7 @@ 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);
> @@ -1883,11 +1882,9 @@ 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 b82bcde..9a4f51e 100644
> --- a/net/ipv6/ip6_fib.c
> +++ b/net/ipv6/ip6_fib.c
> @@ -675,8 +675,7 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
> return -EEXIST;
> iter->dst.expires = rt->dst.expires;
> if (!(rt->rt6i_flags & RTF_EXPIRES)) {
> - iter->rt6i_flags &= ~RTF_EXPIRES;
> - iter->dst.expires = 0;
> + rt6_clean_expires(iter);
> }
> return -EEXIST;
> }
> diff --git a/net/ipv6/route.c b/net/ipv6/route.c
> index 8c2e3ab..dd472f3 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);
> @@ -272,6 +272,10 @@ 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);
> @@ -316,8 +320,18 @@ 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)
> @@ -608,10 +622,9 @@ int rt6_route_rcv(struct net_device *dev, u8 *opt, int len,
>
> if (rt) {
> if (!addrconf_finite_timeout(lifetime)) {
> - rt->rt6i_flags &= ~RTF_EXPIRES;
> + rt6_clean_expires(rt);
> } else {
> - rt->dst.expires = jiffies + HZ * lifetime;
> - rt->rt6i_flags |= RTF_EXPIRES;
> + rt6_set_expires(rt, jiffies + HZ * lifetime);
> }
> dst_release(&rt->dst);
> }
> @@ -717,7 +730,7 @@ 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)
> {
> @@ -934,10 +947,10 @@ 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));
> @@ -1000,8 +1013,7 @@ 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;
> + rt6_update_expires(rt, 0);
> } else if (rt->rt6i_node && (rt->rt6i_flags & RTF_DEFAULT))
> rt->rt6i_node->fn_sernum = -1;
> }
> @@ -1716,8 +1728,8 @@ 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;
> }
>
> @@ -1745,8 +1757,8 @@ 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);
> }
> @@ -1779,7 +1791,7 @@ 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);
> @@ -1799,10 +1811,11 @@ 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;
> + rt6_set_from(rt, ort);
> +
> rt->rt6i_metric = 0;
>
> #ifdef CONFIG_IPV6_SUBTREES
> --
> 1.7.5.4
>
> --
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