Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757853AbbEEKoA (ORCPT ); Tue, 5 May 2015 06:44:00 -0400 Received: from mta-out1.inet.fi ([62.71.2.195]:60233 "EHLO kirsi1.inet.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752532AbbEEKnx (ORCPT ); Tue, 5 May 2015 06:43:53 -0400 X-Greylist: delayed 376 seconds by postgrey-1.27 at vger.kernel.org; Tue, 05 May 2015 06:43:52 EDT From: Markus Stenberg Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Subject: [PATCH] ipv6: Fixed source specific default route handling. Date: Tue, 5 May 2015 13:36:59 +0300 Message-Id: <7922B483-7EA7-4B50-BF1C-7681EB7CC454@iki.fi> Cc: Markus Stenberg To: "David S. Miller" , Alexey Kuznetsov , James Morris , Hideaki YOSHIFUJI , Patrick McHardy , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2098\)) X-Mailer: Apple Mail (2.2098) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3349 Lines: 104 If there are only IPv6 source specific default routes present, the host gets -ENETUNREACH on e.g. connect() because ip6_dst_lookup_tail calls ip6_route_output first, and given source address any, it fails, and ip6_route_get_saddr is never called. The change is to use the ip6_route_get_saddr, even if the initial ip6_route_output fails, and then doing ip6_route_output _again_ after we have appropriate source address available. Note that this is '99% fix' to the problem; a correct fix would be to do route lookups only within addrconf.c when picking a source address, and never call ip6_route_output before source address has been populated. Signed-off-by: Markus Stenberg --- net/ipv6/ip6_output.c | 39 +++++++++++++++++++++++++++++++-------- net/ipv6/route.c | 5 +++-- 2 files changed, 34 insertions(+), 10 deletions(-) diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 7fde1f2..c217775 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -886,22 +886,45 @@ static int ip6_dst_lookup_tail(struct sock *sk, #endif int err; - if (!*dst) - *dst = ip6_route_output(net, sk, fl6); - - err = (*dst)->error; - if (err) - goto out_err_release; + /* The correct way to handle this would be to do + * ip6_route_get_saddr, and then ip6_route_output; however, + * the route-specific preferred source forces the + * ip6_route_output call _before_ ip6_route_get_saddr. + * + * In source specific routing (no src=any default route), + * ip6_route_output will fail given src=any saddr, though, so + * that's why we try it again later. + */ + if (ipv6_addr_any(&fl6->saddr) && (!*dst || !(*dst)->error)) { + struct rt6_info *rt; + bool had_dst = *dst != NULL; - if (ipv6_addr_any(&fl6->saddr)) { - struct rt6_info *rt = (struct rt6_info *) *dst; + if (!had_dst) + *dst = ip6_route_output(net, sk, fl6); + rt = (*dst)->error ? NULL : (struct rt6_info *)*dst; err = ip6_route_get_saddr(net, rt, &fl6->daddr, sk ? inet6_sk(sk)->srcprefs : 0, &fl6->saddr); if (err) goto out_err_release; + + /* If we had an erroneous initial result, pretend it + * never existed and let the SA-enabled version take + * over. + */ + if (!had_dst && (*dst)->error) { + dst_release(*dst); + *dst = NULL; + } } + if (!*dst) + *dst = ip6_route_output(net, sk, fl6); + + err = (*dst)->error; + if (err) + goto out_err_release; + #ifdef CONFIG_IPV6_OPTIMISTIC_DAD /* * Here if the dst entry we've looked up diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 5c48293..d358888 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -2245,9 +2245,10 @@ int ip6_route_get_saddr(struct net *net, unsigned int prefs, struct in6_addr *saddr) { - struct inet6_dev *idev = ip6_dst_idev((struct dst_entry *)rt); + struct inet6_dev *idev = + rt ? ip6_dst_idev((struct dst_entry *)rt) : NULL; int err = 0; - if (rt->rt6i_prefsrc.plen) + if (rt && rt->rt6i_prefsrc.plen) *saddr = rt->rt6i_prefsrc.addr; else err = ipv6_dev_get_saddr(net, idev ? idev->dev : NULL, -- 2.3.2 (Apple Git-55) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/