Date: Thu, 6 Feb 2014 10:48:56 +0000 (UTC) From: "Andrey V. Elsukov" <ae@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r261545 - stable/10/sys/netinet Message-ID: <201402061048.s16Amuqc075717@svn.freebsd.org>
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Author: ae Date: Thu Feb 6 10:48:55 2014 New Revision: 261545 URL: http://svnweb.freebsd.org/changeset/base/261545 Log: MFC r260702 (by melifaro): Fix ipfw fwd for IPv4 traffic broken by r249894. Problem case: Original lookup returns route with GW set, so gw points to rte->rt_gateway. After that we're changing dst and performing lookup another time. Since fwd host is most probably directly reachable, resulting rte does not contain rt_gateway, so gw is not set. Finally, we end with packet transmitted to proper interface but wrong link-layer address. Modified: stable/10/sys/netinet/ip_output.c Directory Properties: stable/10/ (props changed) Modified: stable/10/sys/netinet/ip_output.c ============================================================================== --- stable/10/sys/netinet/ip_output.c Thu Feb 6 10:47:47 2014 (r261544) +++ stable/10/sys/netinet/ip_output.c Thu Feb 6 10:48:55 2014 (r261545) @@ -200,6 +200,13 @@ ip_output(struct mbuf *m, struct mbuf *o hlen = ip->ip_hl << 2; } + /* + * dst/gw handling: + * + * dst can be rewritten but always point to &ro->ro_dst + * gw is readonly but can be pointed either to dst OR rt_gatewy + * therefore we need restore GW if we're re-doing lookup + */ gw = dst = (struct sockaddr_in *)&ro->ro_dst; again: ia = NULL; @@ -219,6 +226,7 @@ again: RO_RTFREE(ro); ro->ro_lle = NULL; rte = NULL; + gw = dst; } if (rte == NULL && fwd_tag == NULL) { bzero(dst, sizeof(*dst));
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