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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-09-29 23:35:10 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-09-29 23:35:10 -0700 |
| commit | 6d0722a2cec2c23db3b0855ff8bb433175a16b44 (patch) | |
| tree | 228a4d1c34a85e68ab9ca14c153c05b6db374c6e /net/ipv4/ip_gre.c | |
| parent | 9812cb12c9d58c5d9aead84eb2e7864c68c80302 (diff) | |
| download | linux-3.10-6d0722a2cec2c23db3b0855ff8bb433175a16b44.tar.gz linux-3.10-6d0722a2cec2c23db3b0855ff8bb433175a16b44.tar.bz2 linux-3.10-6d0722a2cec2c23db3b0855ff8bb433175a16b44.zip | |
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.c | 8 |
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, |