| 1 | From d11a4dc18bf41719c9f0d7ed494d295dd2973b92 Mon Sep 17 00:00:00 2001
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| 2 | From: =?utf8?q?Timo=20Ter=C3=A4s?= <[email protected]>
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| 3 | Date: Thu, 18 Mar 2010 23:20:20 +0000
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| 4 | Subject: [PATCH] ipv4: check rt_genid in dst_check
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| 5 |
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| 6 | Xfrm_dst keeps a reference to ipv4 rtable entries on each
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| 7 | cached bundle. The only way to renew xfrm_dst when the underlying
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| 8 | route has changed, is to implement dst_check for this. This is
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| 9 | what ipv6 side does too.
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| 10 |
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| 11 | The problems started after 87c1e12b5eeb7b30b4b41291bef8e0b41fc3dde9
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| 12 | ("ipsec: Fix bogus bundle flowi") which fixed a bug causing xfrm_dst
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| 13 | to not get reused, until that all lookups always generated new
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| 14 | xfrm_dst with new route reference and path mtu worked. But after the
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| 15 | fix, the old routes started to get reused even after they were expired
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| 16 | causing pmtu to break (well it would occationally work if the rtable
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| 17 | gc had run recently and marked the route obsolete causing dst_check to
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| 18 | get called).
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| 19 |
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| 20 | Signed-off-by: Timo Teras <[email protected]>
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| 21 | Acked-by: Herbert Xu <[email protected]>
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| 22 | Signed-off-by: David S. Miller <[email protected]>
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| 23 | ---
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| 24 | net/ipv4/route.c | 14 ++++++++++----
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| 25 | 1 files changed, 10 insertions(+), 4 deletions(-)
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| 26 |
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| 27 | diff --git a/net/ipv4/route.c b/net/ipv4/route.c
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| 28 | index a770df2..32d3961 100644
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| 29 | |
| 30 | |
| 31 | @@ -1441,7 +1441,7 @@ void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
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| 32 | dev_hold(rt->u.dst.dev);
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| 33 | if (rt->idev)
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| 34 | in_dev_hold(rt->idev);
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| 35 | - rt->u.dst.obsolete = 0;
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| 36 | + rt->u.dst.obsolete = -1;
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| 37 | rt->u.dst.lastuse = jiffies;
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| 38 | rt->u.dst.path = &rt->u.dst;
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| 39 | rt->u.dst.neighbour = NULL;
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| 40 | @@ -1506,7 +1506,7 @@ static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
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| 41 | struct dst_entry *ret = dst;
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| 42 |
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| 43 | if (rt) {
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| 44 | - if (dst->obsolete) {
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| 45 | + if (dst->obsolete > 0) {
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| 46 | ip_rt_put(rt);
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| 47 | ret = NULL;
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| 48 | } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
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| 49 | @@ -1726,7 +1726,9 @@ static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu)
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| 50 |
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| 51 | static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
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| 52 | {
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| 53 | - return NULL;
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| 54 | + if (rt_is_expired((struct rtable *)dst))
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| 55 | + return NULL;
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| 56 | + return dst;
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| 57 | }
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| 58 |
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| 59 | static void ipv4_dst_destroy(struct dst_entry *dst)
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| 60 | @@ -1888,7 +1890,8 @@ static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
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| 61 | if (!rth)
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| 62 | goto e_nobufs;
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| 63 |
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| 64 | - rth->u.dst.output= ip_rt_bug;
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| 65 | + rth->u.dst.output = ip_rt_bug;
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| 66 | + rth->u.dst.obsolete = -1;
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| 67 |
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| 68 | atomic_set(&rth->u.dst.__refcnt, 1);
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| 69 | rth->u.dst.flags= DST_HOST;
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| 70 | @@ -2054,6 +2057,7 @@ static int __mkroute_input(struct sk_buff *skb,
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| 71 | rth->fl.oif = 0;
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| 72 | rth->rt_spec_dst= spec_dst;
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| 73 |
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| 74 | + rth->u.dst.obsolete = -1;
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| 75 | rth->u.dst.input = ip_forward;
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| 76 | rth->u.dst.output = ip_output;
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| 77 | rth->rt_genid = rt_genid(dev_net(rth->u.dst.dev));
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| 78 | @@ -2218,6 +2222,7 @@ local_input:
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| 79 | goto e_nobufs;
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| 80 |
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| 81 | rth->u.dst.output= ip_rt_bug;
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| 82 | + rth->u.dst.obsolete = -1;
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| 83 | rth->rt_genid = rt_genid(net);
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| 84 |
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| 85 | atomic_set(&rth->u.dst.__refcnt, 1);
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| 86 | @@ -2444,6 +2449,7 @@ static int __mkroute_output(struct rtable **result,
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| 87 | rth->rt_spec_dst= fl->fl4_src;
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| 88 |
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| 89 | rth->u.dst.output=ip_output;
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| 90 | + rth->u.dst.obsolete = -1;
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| 91 | rth->rt_genid = rt_genid(dev_net(dev_out));
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| 92 |
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| 93 | RT_CACHE_STAT_INC(out_slow_tot);
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| 94 | --
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| 95 | 1.7.1
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| 96 |
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