[RESEND PATCH net-next v2 1/4] net/ipv6: flatten ip6_route_get_saddr

[David Lamparter <equinox@diac24.net>]

Inline ip6_route_get_saddr()'s functionality in rt6_fill_node(), to
prepare for replacing the former with a dst based function.

NB: the l3mdev handling introduced by 252442f2ae31 "ipv6: fix source
address selection with route leak" is dropped here - the l3mdev ifindex
was a constant 0 on this call site, so that code was in fact dead.

Signed-off-by: David Lamparter <equinox@diac24.net>
---
 net/ipv6/route.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index aee6a10b112a..9508e46b9e56 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -5822,9 +5822,19 @@ static int rt6_fill_node(struct net *net, struct sk_buff *skb,
 			if (nla_put_u32(skb, RTA_IIF, iif))
 				goto nla_put_failure;
 	} else if (dest) {
-		struct in6_addr saddr_buf;
-		if (ip6_route_get_saddr(net, rt, dest, 0, 0, &saddr_buf) == 0 &&
-		    nla_put_in6_addr(skb, RTA_PREFSRC, &saddr_buf))
+		struct in6_addr saddr_buf, *saddr = NULL;
+
+		if (rt->fib6_prefsrc.plen) {
+			saddr = &rt->fib6_prefsrc.addr;
+		} else {
+			struct net_device *dev = fib6_info_nh_dev(rt);
+
+			if (ipv6_dev_get_saddr(net, dev, dest, 0,
+					       &saddr_buf) == 0)
+				saddr = &saddr_buf;
+		}
+
+		if (saddr && nla_put_in6_addr(skb, RTA_PREFSRC, saddr))
 			goto nla_put_failure;
 	}
 
-- 
2.50.1