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Commit 6d0722a2 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ip_gre: comments change 



HARD_TX_LOCK no longer protects tunnels from dead loops,
but xmit_recursion percpu counter.

Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9812cb12

net/ipv4/ip_gre.c

+4 −4
Original line number Diff line number Diff line
@@ -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,