From owner-freebsd-net@freebsd.org  Tue Feb 21 22:50:34 2017
Return-Path: <owner-freebsd-net@freebsd.org>
Delivered-To: freebsd-net@mailman.ysv.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 by mailman.ysv.freebsd.org (Postfix) with ESMTP id 33880CE8200
 for <freebsd-net@mailman.ysv.freebsd.org>;
 Tue, 21 Feb 2017 22:50:34 +0000 (UTC)
 (envelope-from prabhakar.lakhera@gmail.com)
Received: from mail-qk0-x22f.google.com (mail-qk0-x22f.google.com
 [IPv6:2607:f8b0:400d:c09::22f])
 (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits))
 (Client CN "smtp.gmail.com",
 Issuer "Google Internet Authority G2" (verified OK))
 by mx1.freebsd.org (Postfix) with ESMTPS id EADA01D1C
 for <freebsd-net@freebsd.org>; Tue, 21 Feb 2017 22:50:33 +0000 (UTC)
 (envelope-from prabhakar.lakhera@gmail.com)
Received: by mail-qk0-x22f.google.com with SMTP id n127so12386310qkf.0
 for <freebsd-net@freebsd.org>; Tue, 21 Feb 2017 14:50:33 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025;
 h=mime-version:from:date:message-id:subject:to;
 bh=LOSxwyrlieI0UjHGGIYsOql6oLDgVtz/yYkRHOQD+rY=;
 b=R1nGX2BukgbsYVtXSc8ODNKPeXQ6gmqZrtpbK8mReKR8KQv4Sid62hrVREuUNjEWlo
 Ga8CPZy06UVAc1Y9kD7WTu4XAPoYttkR2MgrcdvbinqqKf2eNj9FRgCOb+U2Mz4wAT7d
 A8bWTA+iEEXrHY0ETzx3696eI2+1RzTKdxqlDWXvD/pbir8PtQ1j734Prvwy8IlViqIK
 epbl2jaoH9PZ5pLqtSy1mJEqae2B18qAa0bHjo9x/06Nbyfh8fHUvEVWqb4Ol/1Sn0ax
 kT7KeXxaeq9Obg3IBoHZV0/l8Uzy0u4km+4o1HYqTJPKf1yXRAm1yd68ptir1dib3QGc
 cNYQ==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
 d=1e100.net; s=20161025;
 h=x-gm-message-state:mime-version:from:date:message-id:subject:to;
 bh=LOSxwyrlieI0UjHGGIYsOql6oLDgVtz/yYkRHOQD+rY=;
 b=T3J8t79UbIYu006ii9O4efag/05ZwBpDgvvktD4Mw3J0ADV9TZSB3LWWYSWPFaQrXS
 X20QxmbLJ5JH3qSEDp7y/iMf50b1oimud03KFcdVK0F+9xFJnx/PA0xNwC5Qimwg48NU
 rM+VeN8OY8X7jxxCHo5rB5ox7oTre22yRkPmO555xImaScGPF7PRNGyNDvjKJkDBwi/e
 zyZzXf41t8IvGZKA/69TMQgeuveeHNJFHGsXRDYl8WjpupcLAZHywuoC7/bc9qXPmptd
 8pR6se5D++0FSj8Q6I7E4Q4diXfCOxKy92PF3iVAxGrpsAtY1IvgfqsRWV5dJKkSrcxD
 KBqQ==
X-Gm-Message-State: AMke39lPNVhQ9ejMr7xaK9xpZrLjdw5Iu5yPlgfBzg0bImydCDhQ6FZTFYN0BBHI11i92Pd1NhT/htBbKt1ZqQ==
X-Received: by 10.55.204.197 with SMTP id n66mr26832910qkl.291.1487717433016; 
 Tue, 21 Feb 2017 14:50:33 -0800 (PST)
MIME-Version: 1.0
Received: by 10.140.83.37 with HTTP; Tue, 21 Feb 2017 14:50:32 -0800 (PST)
From: prabhakar lakhera <prabhakar.lakhera@gmail.com>
Date: Tue, 21 Feb 2017 14:50:32 -0800
Message-ID: <CALg+rhUBr7q0jamGgzRbFreMnjRg+-qvNiH95D8O4iO34u=+iA@mail.gmail.com>
Subject: Bug in ICMP redirect handling
To: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>
Content-Type: text/plain; charset=UTF-8
X-Content-Filtered-By: Mailman/MimeDel 2.1.23
X-BeenThere: freebsd-net@freebsd.org
X-Mailman-Version: 2.1.23
Precedence: list
List-Id: Networking and TCP/IP with FreeBSD <freebsd-net.freebsd.org>
List-Unsubscribe: <https://lists.freebsd.org/mailman/options/freebsd-net>,
 <mailto:freebsd-net-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-net/>
List-Post: <mailto:freebsd-net@freebsd.org>
List-Help: <mailto:freebsd-net-request@freebsd.org?subject=help>
List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/freebsd-net>,
 <mailto:freebsd-net-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 21 Feb 2017 22:50:34 -0000

This seems like a bug:

https://svnweb.freebsd.org/base/head/sys/netinet/tcp_subr.c?r1=303457&r2=303456&pathrev=303457

I believe the ordering of if/else checks for cmd value is important as the
last one checks for mapping of PRC* to an error.

Given that the mapping is defined to be 0 for redirects (only cached routes
are supposed to be invalidated), looks like right now we'll simply return
from:

else if ((unsigned)cmd >= PRC_NCMDS || *inetctlerrmap[cmd] == 0)* return;

The above is I guess is only in the head and not in a major version yet.