ipv6: ignore dst hint for multipath routes

[ Upstream commit 8423be8926aa82cd2e28bba5cc96ccb72c7ce6be ]

Route hints when the nexthop is part of a multipath group causes packets
in the same receive batch to be sent to the same nexthop irrespective of
the multipath hash of the packet. So, do not extract route hint for
packets whose destination is part of a multipath group.

A new SKB flag IP6SKB_MULTIPATH is introduced for this purpose, set the
flag when route is looked up in fib6_select_path() and use it in
ip6_can_use_hint() to check for the existence of the flag.

Fixes: 197dbf24e360 ("ipv6: introduce and uses route look hints for list input.")
Signed-off-by: Sriram Yagnaraman <sriram.yagnaraman@est.tech>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 37dfdcfcdd542fe0efc9a1df967be3da931635d4..15d7529ac95348efb2edcbf2c6379bd6545ee42a 100644 (file)
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -146,6 +146,7 @@ struct inet6_skb_parm {
 #define IP6SKB_JUMBOGRAM      128
 #define IP6SKB_SEG6          256
 #define IP6SKB_FAKEJUMBO      512
+#define IP6SKB_MULTIPATH      1024
 };
 
 #if defined(CONFIG_NET_L3_MASTER_DEV)

diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index d94041bb42872f02eaaa5bd2f64ae2301a8a48a4..b8378814532cead0275e8b7a656f78450993f619 100644 (file)
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -99,7 +99,8 @@ static bool ip6_can_use_hint(const struct sk_buff *skb,
 static struct sk_buff *ip6_extract_route_hint(const struct net *net,
                                              struct sk_buff *skb)
 {
-       if (fib6_routes_require_src(net) || fib6_has_custom_rules(net))
+       if (fib6_routes_require_src(net) || fib6_has_custom_rules(net) ||
+           IP6CB(skb)->flags & IP6SKB_MULTIPATH)
                return NULL;
 
        return skb;

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 960ab43a49c4632b93d1761120e997651334ed38..93957b20fccceed2e1e56432fe76bd9a6dce780f 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -425,6 +425,9 @@ void fib6_select_path(const struct net *net, struct fib6_result *res,
        if (match->nh && have_oif_match && res->nh)
                return;
 
+       if (skb)
+               IP6CB(skb)->flags |= IP6SKB_MULTIPATH;
+
        /* We might have already computed the hash for ICMPv6 errors. In such
         * case it will always be non-zero. Otherwise now is the time to do it.
         */