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authorEric Dumazet <eric.dumazet@gmail.com>2010-09-29 23:35:10 -0700
committerDavid S. Miller <davem@davemloft.net>2010-09-29 23:35:10 -0700
commit6d0722a2cec2c23db3b0855ff8bb433175a16b44 (patch)
tree228a4d1c34a85e68ab9ca14c153c05b6db374c6e /net/ipv4/ip_gre.c
parent9812cb12c9d58c5d9aead84eb2e7864c68c80302 (diff)
ip_gre: comments change
HARD_TX_LOCK no longer protects tunnels from dead loops, but xmit_recursion percpu counter. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/ip_gre.c')
-rw-r--r--net/ipv4/ip_gre.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 035db635003..fbe2c473a06 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -64,13 +64,13 @@
We cannot track such dead loops during route installation,
it is infeasible task. The most general solutions would be
to keep skb->encapsulation counter (sort of local ttl),
- and silently drop packet when it expires. It is the best
+ and silently drop packet when it expires. It is a good
solution, but it supposes maintaing new variable in ALL
skb, even if no tunneling is used.
- Current solution: HARD_TX_LOCK lock breaks dead loops.
-
-
+ Current solution: xmit_recursion breaks dead loops. This is a percpu
+ counter, since when we enter the first ndo_xmit(), cpu migration is
+ forbidden. We force an exit if this counter reaches RECURSION_LIMIT
2. Networking dead loops would not kill routers, but would really
kill network. IP hop limit plays role of "t->recursion" in this case,