Get TOS from IP header

Get TOS from IP header

[Naveen B N (nbn)]

Hi All,

I want  to get the TOS field content from IP header at 
my application which is using SCTP protocol.
I know that it can be done by Using RAW socket but 
There is a over head of implementing the sctp at the 
Application layer . 
Is there a better way of getting a TOS field filled
Which we received from IP header.

I taught of adding code in kernel to recognize a socket option at the kernel,
If this option is set just and get TOS contents in receive .

Please let me know if this is the way to go about it or is there 
A better way to achieve the same .

Thanks and Regards
Naveen

Re: Get TOS from IP header

[Eric Dumazet]

Le mardi 22 novembre 2011 à 07:06 +0530, Naveen B N (nbn) a écrit :
> Hi All,
> 
> I want  to get the TOS field content from IP header at 
> my application which is using SCTP protocol.
> I know that it can be done by Using RAW socket but 
> There is a over head of implementing the sctp at the 
> Application layer . 
> Is there a better way of getting a TOS field filled
> Which we received from IP header.
> 
> I taught of adding code in kernel to recognize a socket option at the kernel,
> If this option is set just and get TOS contents in receive .
> 
> Please let me know if this is the way to go about it or is there 
> A better way to achieve the same .
> 

I believe SCTP is not yet described in "man 7 ip", but since its
obviously an IP protocol, all things described in this man page should
work.

       IP_RECVTOS (since Linux 2.2)
              If enabled the IP_TOS ancillary message is passed with  incoming  packets.
              It contains a byte which specifies the Type of Service/Precedence field of
              the packet header.  Expects a boolean integer flag.