ipv4: ignore dst hint for multipath routes

[ Upstream commit 6ac66cb03ae306c2e288a9be18226310529f5b25 ]

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 IPSKB_MULTIPATH is introduced for this purpose, set the
flag when route is looked up in ip_mkroute_input() and use it in
ip_extract_route_hint() to check for the existence of the flag.

Fixes: 02b24941619f ("ipv4: use dst hint for ipv4 list receive")
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/net/ip.h b/include/net/ip.h
index 1872f570abeda74066dc6f7c73fb98952622f675..c286344628dbacef0a9657fcdc5df5efe6a65da4 100644 (file)
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -57,6 +57,7 @@ struct inet_skb_parm {
 #define IPSKB_FRAG_PMTU                BIT(6)
 #define IPSKB_L3SLAVE          BIT(7)
 #define IPSKB_NOPOLICY         BIT(8)
+#define IPSKB_MULTIPATH                BIT(9)
 
        u16                     frag_max_size;
 };

diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index e880ce77322aaa5043dd12fbbd487d8361661673..e7196ecffafc65b200d43a2defba0d109a7f870c 100644 (file)
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -584,7 +584,8 @@ static void ip_sublist_rcv_finish(struct list_head *head)
 static struct sk_buff *ip_extract_route_hint(const struct net *net,
                                             struct sk_buff *skb, int rt_type)
 {
-       if (fib4_has_custom_rules(net) || rt_type == RTN_BROADCAST)
+       if (fib4_has_custom_rules(net) || rt_type == RTN_BROADCAST ||
+           IPCB(skb)->flags & IPSKB_MULTIPATH)
                return NULL;
 
        return skb;

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 51bd9a50a1d1dd7c82f241b8c59003a5a248e3e3..a04ffc128e22b260ed5b12f90a86293f6c8750f5 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2146,6 +2146,7 @@ static int ip_mkroute_input(struct sk_buff *skb,
                int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys);
 
                fib_select_multipath(res, h);
+               IPCB(skb)->flags |= IPSKB_MULTIPATH;
        }
 #endif