linux: backport IPv6 SAS fixes for source-specific routes

Signed-off-by: Steven Barth <steven@midlink.org>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@45699 3c298f89-4303-0410-b956-a3cf2f4a3e73

diff --git a/target/linux/generic/patches-3.18/667-ipv6-Fixed-source-specific-default-route-handling.patch b/target/linux/generic/patches-3.18/667-ipv6-Fixed-source-specific-default-route-handling.patch
new file mode 100644 (file)
index 0000000..db93ee1
--- /dev/null
+++ b/target/linux/generic/patches-3.18/667-ipv6-Fixed-source-specific-default-route-handling.patch
@@ -0,0 +1,98 @@
+From e16e888b525503be05b3aea64190e8b3bdef44d0 Mon Sep 17 00:00:00 2001
+From: Markus Stenberg <markus.stenberg@iki.fi>
+Date: Tue, 5 May 2015 13:36:59 +0300
+Subject: [PATCH] ipv6: Fixed source specific default route handling.
+
+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 <markus.stenberg@iki.fi>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ 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
+@@ -897,21 +897,45 @@ static int ip6_dst_lookup_tail(struct so
+ #endif
+       int err;
+ 
+-      if (*dst == NULL)
+-              *dst = ip6_route_output(net, sk, fl6);
+-
+-      if ((err = (*dst)->error))
+-              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
+--- a/net/ipv6/route.c
++++ b/net/ipv6/route.c
+@@ -2215,9 +2215,10 @@ 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,

diff --git a/target/linux/generic/patches-4.0/667-ipv6-Fixed-source-specific-default-route-handling.patch b/target/linux/generic/patches-4.0/667-ipv6-Fixed-source-specific-default-route-handling.patch
new file mode 100644 (file)
index 0000000..b5cc76d
--- /dev/null
+++ b/target/linux/generic/patches-4.0/667-ipv6-Fixed-source-specific-default-route-handling.patch
@@ -0,0 +1,104 @@
+From e16e888b525503be05b3aea64190e8b3bdef44d0 Mon Sep 17 00:00:00 2001
+From: Markus Stenberg <markus.stenberg@iki.fi>
+Date: Tue, 5 May 2015 13:36:59 +0300
+Subject: [PATCH] ipv6: Fixed source specific default route handling.
+
+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 <markus.stenberg@iki.fi>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ 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,
+-- 
+2.1.4
+