[PATCH] netfilter: use fwmark_reflect in nf_send_reset

[Pau Espin Pedrol <pau.espin@tessares.net>]

Otherwise, RST packets generated by ipt_REJECT always have mark 0 when
the routing is checked later in the same code path.

Fixes: e110861f8609 ("net: add a sysctl to reflect the fwmark on replies")
Cc: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: Pau Espin Pedrol <pau.espin@tessares.net>
---
 net/ipv4/netfilter/nf_reject_ipv4.c | 2 ++
 net/ipv6/netfilter/nf_reject_ipv6.c | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/net/ipv4/netfilter/nf_reject_ipv4.c b/net/ipv4/netfilter/nf_reject_ipv4.c
index fd82202..146d861 100644
--- a/net/ipv4/netfilter/nf_reject_ipv4.c
+++ b/net/ipv4/netfilter/nf_reject_ipv4.c
@@ -126,6 +126,8 @@ void nf_send_reset(struct net *net, struct sk_buff *oldskb, int hook)
 	/* ip_route_me_harder expects skb->dst to be set */
 	skb_dst_set_noref(nskb, skb_dst(oldskb));
 
+	nskb->mark = IP4_REPLY_MARK(net, oldskb->mark);
+
 	skb_reserve(nskb, LL_MAX_HEADER);
 	niph = nf_reject_iphdr_put(nskb, oldskb, IPPROTO_TCP,
 				   ip4_dst_hoplimit(skb_dst(nskb)));
diff --git a/net/ipv6/netfilter/nf_reject_ipv6.c b/net/ipv6/netfilter/nf_reject_ipv6.c
index 1009040..1e2cc8e 100644
--- a/net/ipv6/netfilter/nf_reject_ipv6.c
+++ b/net/ipv6/netfilter/nf_reject_ipv6.c
@@ -152,6 +152,7 @@ void nf_send_reset6(struct net *net, struct sk_buff *oldskb, int hook)
 
 	memset(&fl6, 0, sizeof(fl6));
 	fl6.flowi6_proto = IPPROTO_TCP;
+	fl6.flowi6_mark = IP6_REPLY_MARK(net, oldskb->mark);
 	fl6.saddr = oip6h->daddr;
 	fl6.daddr = oip6h->saddr;
 	fl6.fl6_sport = otcph->dest;
@@ -180,6 +181,8 @@ void nf_send_reset6(struct net *net, struct sk_buff *oldskb, int hook)
 
 	skb_dst_set(nskb, dst);
 
+	nskb->mark = fl6.flowi6_mark;
+
 	skb_reserve(nskb, hh_len + dst->header_len);
 	ip6h = nf_reject_ip6hdr_put(nskb, oldskb, IPPROTO_TCP,
 				    ip6_dst_hoplimit(dst));
-- 
2.7.4


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