From: Eric Dumazet <eric.dumazet@gmail•com>
To: thomas yang <lampsu@gmail•com>
Cc: netdev@vger•kernel.org
Subject: Re: IP header identification field is zero, why?
Date: Thu, 08 Oct 2009 11:18:28 +0200 [thread overview]
Message-ID: <4ACDAE64.5020101@gmail.com> (raw)
In-Reply-To: <f4f837ab0910080208g143ceb1dj538680ff62e6bb37@mail.gmail.com>
thomas yang a écrit :
> The IP ID for TCP is non-zero, but for UDP is zero, strange.
>
> I want to make the IP ID (not always zero) for UDP packets, what should I do?
> (I want to use 'IP header ID, flags, offset, protocol' to identify an
> IP packets)
As I said, you can connect() your udp socket, if you send/receive trafic to/from a given destination.
if (connected_sock)
res = connect(sock, (struct sockaddr *)&addr, sizeof(addr));
(Only once)
Then, your sendto() can be faster (because no route lookup is performed)
if (sendto(sock, buffer, psize, 0,
connected_socks ? NULL : (struct sockaddr *)&addr,
sizeof(struct sockaddr_in)) != -1)
Then linux *will* generate an ID for each datagram.
prev parent reply other threads:[~2009-10-08 9:19 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-07 14:04 IP header identification field is zero, why? thomas yang
2009-10-07 14:55 ` Eric Dumazet
2009-10-08 9:08 ` thomas yang
2009-10-08 9:18 ` Eric Dumazet [this message]
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