From mboxrd@z Thu Jan 1 00:00:00 1970 From: Willem de Bruijn Subject: [PATCH net-next 0/3] ip: add RECVFRAGSIZE cmsg Date: Wed, 2 Nov 2016 11:02:15 -0400 Message-ID: <1478098938-124108-1-git-send-email-willemdebruijn.kernel@gmail.com> Cc: jdorfman@google.com, eric.dumazet@gmail.com, davem@davemloft.net, Willem de Bruijn To: netdev@vger.kernel.org Return-path: Received: from mail-qk0-f195.google.com ([209.85.220.195]:32769 "EHLO mail-qk0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752400AbcKBPCX (ORCPT ); Wed, 2 Nov 2016 11:02:23 -0400 Received: by mail-qk0-f195.google.com with SMTP id x190so1411548qkb.0 for ; Wed, 02 Nov 2016 08:02:22 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: From: Willem de Bruijn On IP datagrams and raw sockets, when packets arrive fragmented, expose the largest received fragment size through a new cmsg. Protocols implemented on top of these sockets may use this, for instance, to inform peers to lower MSS on platforms that silently allow send calls to exceed PMTU and cause fragmentation. Willem de Bruijn (3): ipv4: add IP_RECVFRAGSIZE cmsg ipv6: add IPV6_RECVFRAGSIZE cmsg ipv6: on reassembly, record frag_max_size include/linux/ipv6.h | 5 +++-- include/net/inet_sock.h | 1 + include/uapi/linux/in.h | 1 + include/uapi/linux/in6.h | 1 + net/ipv4/ip_sockglue.c | 26 ++++++++++++++++++++++++++ net/ipv6/datagram.c | 5 +++++ net/ipv6/ipv6_sockglue.c | 8 ++++++++ net/ipv6/reassembly.c | 7 ++++++- 8 files changed, 51 insertions(+), 3 deletions(-) -- 2.8.0.rc3.226.g39d4020