From d218d11133d888f9745802146a50255a4781d37a Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Mon, 11 Jan 2010 16:28:01 -0800 Subject: 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 Signed-off-by: David S. Miller --- include/net/inet_sock.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'include/net/inet_sock.h') diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h index bd4c53f75ac0..83fd34437cf1 100644 --- a/include/net/inet_sock.h +++ b/include/net/inet_sock.h @@ -122,10 +122,12 @@ struct inet_sock { __be32 inet_saddr; __s16 uc_ttl; __u16 cmsg_flags; - struct ip_options *opt; __be16 inet_sport; __u16 inet_id; + + struct ip_options *opt; __u8 tos; + __u8 min_ttl; __u8 mc_ttl; __u8 pmtudisc; __u8 recverr:1, -- cgit v1.2.3