From mboxrd@z Thu Jan 1 00:00:00 1970 From: raj@tardy.usa.hp.com (Rick Jones) Subject: [PATCH net-next] net: track success and failure of TCP PMTU probing Date: Tue, 21 Jul 2015 16:14:13 -0700 (PDT) Message-ID: <20150721231413.9BCA62900711@tardy> Cc: To: Return-path: Received: from g2t1383g.austin.hp.com ([15.217.136.92]:48846 "EHLO g2t1383g.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932830AbbGUXOX (ORCPT ); Tue, 21 Jul 2015 19:14:23 -0400 Received: from g1t5424.austin.hp.com (g1t5424.austin.hp.com [15.216.225.54]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by g2t1383g.austin.hp.com (Postfix) with ESMTPS id F2E835729 for ; Tue, 21 Jul 2015 23:14:15 +0000 (UTC) Sender: netdev-owner@vger.kernel.org List-ID: From: Rick Jones Track success and failure of TCP PMTU probing. Signed-off-by: Rick Jones --- Tested by loading-up into an OpenStack instance and kicking the MTU out from under it in the corresponding router namespace. diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h index eee8968..25a9ad8 100644 --- a/include/uapi/linux/snmp.h +++ b/include/uapi/linux/snmp.h @@ -278,6 +278,8 @@ enum LINUX_MIB_TCPACKSKIPPEDCHALLENGE, /* TCPACKSkippedChallenge */ LINUX_MIB_TCPWINPROBE, /* TCPWinProbe */ LINUX_MIB_TCPKEEPALIVE, /* TCPKeepAlive */ + LINUX_MIB_TCPMTUPFAIL, /* TCPMTUPFail */ + LINUX_MIB_TCPMTUPSUCCESS, /* TCPMTUPSuccess */ __LINUX_MIB_MAX }; diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c index da5d483..3abd9d7 100644 --- a/net/ipv4/proc.c +++ b/net/ipv4/proc.c @@ -300,6 +300,8 @@ static const struct snmp_mib snmp4_net_list[] = { SNMP_MIB_ITEM("TCPACKSkippedChallenge", LINUX_MIB_TCPACKSKIPPEDCHALLENGE), SNMP_MIB_ITEM("TCPWinProbe", LINUX_MIB_TCPWINPROBE), SNMP_MIB_ITEM("TCPKeepAlive", LINUX_MIB_TCPKEEPALIVE), + SNMP_MIB_ITEM("TCPMTUPFail", LINUX_MIB_TCPMTUPFAIL), + SNMP_MIB_ITEM("TCPMTUPSuccess", LINUX_MIB_TCPMTUPSUCCESS), SNMP_MIB_SENTINEL }; diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 1578fc2..cda3ffe 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2593,6 +2593,7 @@ static void tcp_mtup_probe_failed(struct sock *sk) icsk->icsk_mtup.search_high = icsk->icsk_mtup.probe_size - 1; icsk->icsk_mtup.probe_size = 0; + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMTUPFAIL); } static void tcp_mtup_probe_success(struct sock *sk) @@ -2612,6 +2613,7 @@ static void tcp_mtup_probe_success(struct sock *sk) icsk->icsk_mtup.search_low = icsk->icsk_mtup.probe_size; icsk->icsk_mtup.probe_size = 0; tcp_sync_mss(sk, icsk->icsk_pmtu_cookie); + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMTUPSUCCESS); } /* Do a simple retransmit without using the backoff mechanisms in