diff options
| author | Stephen Hemminger <shemminger@vyatta.com> | 2010-01-11 16:28:01 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-01-11 16:28:01 -0800 |
| commit | d218d11133d888f9745802146a50255a4781d37a (patch) | |
| tree | 3b4b163238e19c48f37f3d8a77eb27f3a18691a0 /net/ipv4/tcp_ipv4.c | |
| parent | c8e000604bce02a87742240a9b716a0f1b680c0b (diff) | |
tcp: Generalized TTL Security Mechanism
This patch adds the kernel portions needed to implement
RFC 5082 Generalized TTL Security Mechanism (GTSM).
It is a lightweight security measure against forged
packets causing DoS attacks (for BGP).
This is already implemented the same way in BSD kernels.
For the necessary Quagga patch
http://www.gossamer-threads.com/lists/quagga/dev/17389
Description from Cisco
http://www.cisco.com/en/US/docs/ios/12_3t/12_3t7/feature/guide/gt_btsh.html
It does add one byte to each socket structure, but I did
a little rearrangement to reuse a hole (on 64 bit), but it
does grow the structure on 32 bit
This should be documented on ip(4) man page and the Glibc in.h
file also needs update. IPV6_MINHOPLIMIT should also be added
(although BSD doesn't support that).
Only TCP is supported, but could also be added to UDP, DCCP, SCTP
if desired.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_ipv4.c')
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 65b8ebfd078..382f667238e 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1649,6 +1649,9 @@ int tcp_v4_rcv(struct sk_buff *skb) if (!sk) goto no_tcp_socket; + if (iph->ttl < inet_sk(sk)->min_ttl) + goto discard_and_relse; + process: if (sk->sk_state == TCP_TIME_WAIT) goto do_time_wait; |