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 fc05e016be060146c021cb283c91d6297a62801f..e1a93c3391090fc3b6a2c7c4d00f430d74a7a53f 100644 (file)
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -56,6 +56,7 @@ 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 124bf8fdf924a6bf644deaeb8bf78735ae80ecd6..5d0bc0dbdb4d98b3ca966911277f98a9fc09cdc2 100644 (file)
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -581,7 +581,8 @@ 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 ca59b61fd3a3150d91d6ad5375d73d91e526264f..bc6240d327a8ffc5c3c07a4202b3ed2a0fec9e0c 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2151,6 +2151,7 @@ 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