Fix check for incorrect or missing sequence mumbers in

This patch fix the incorrect or missing sequence mumbers in ICMP message, add the check for incorrect or missing sequence mumbers in ICMPv6 message.

[PATCH 1/4] DCCP: Fix to check the sequence number in ICMP message correctly [PATCH 2/4] DCCP: Add check for sequence number in ICMPv6 message [PATCH 3/4] DCCP: Fix to check missing sequence number for ICMP message correctly [PATCH 4/4] DCCP: Add check for missing sequence number in ICMPv6 message

| This patch fix the incorrect or missing sequence mumbers in ICMP
| message, add the check for incorrect or missing sequence mumbers in
| ICMPv6 message.
| 
| [PATCH 1/4] DCCP: Fix to check the sequence number in ICMP message correctly
| [PATCH 2/4] DCCP: Add check for sequence number in ICMPv6 message
| [PATCH 3/4] DCCP: Fix to check missing sequence number for ICMP message correctly
| [PATCH 4/4] DCCP: Add check for missing sequence number in ICMPv6 message
| 
| 

Thank you. I will work through these and review. Two comments so far
* they apply not cleanly (to 2.6.26) -- please check your kernel sources;
* in patches 3/4 the "if (skb->len < ihlen + 12" can be omitted, since __dccp_basic_hdr_len() always returns minimally sizeof(struct dccp_hdr) = 12 (the header size of 8 seems to stem from an earlier draft version of DCCP).

Gerrit

Agree, I will fix the patch. I think she header size of 8 may be caome from the tcp code^_^?

Yes, it is the same in tcp_v4_err() in net/ipv4/tcp_ipv4.c and I think that is because of RFC 1122, 3.2.2:
"Every ICMP error message includes the Internet header and at
least the first 8 data octets of the datagram that triggered the error; more than 8 octets MAY be sent; this header and data MUST be unchanged from the received datagram."

In TCP it is possible to get at the sequence number with the first 8 octets, in DCCP this is at least 12 bytes as correctly pointed out by your patch changelog.