ipv4: Fix bugs in fib_compute_spec_dst().
Based upon feedback from Julian Anastasov.
1) Use route flags to determine multicast/broadcast, not the
packet flags.
2) Leave saddr unspecified in flow key.
3) Adjust how we invoke inet_select_addr(). Pass ip_hdr(skb)->saddr as
second arg, and if it was zeronet use link scope.
4) Use loopback as input interface in flow key.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 63b11ca..1d13217 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -185,28 +185,36 @@
struct net_device *dev = skb->dev;
struct in_device *in_dev;
struct fib_result res;
+ struct rtable *rt;
struct flowi4 fl4;
struct net *net;
+ int scope;
- if (skb->pkt_type != PACKET_BROADCAST &&
- skb->pkt_type != PACKET_MULTICAST)
+ rt = skb_rtable(skb);
+ if (!(rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)))
return ip_hdr(skb)->daddr;
in_dev = __in_dev_get_rcu(dev);
BUG_ON(!in_dev);
- fl4.flowi4_oif = 0;
- fl4.flowi4_iif = 0;
- fl4.daddr = ip_hdr(skb)->saddr;
- fl4.saddr = ip_hdr(skb)->daddr;
- fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos);
- fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
- fl4.flowi4_mark = IN_DEV_SRC_VMARK(in_dev) ? skb->mark : 0;
net = dev_net(dev);
- if (!fib_lookup(net, &fl4, &res))
- return FIB_RES_PREFSRC(net, res);
- else
- return inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
+
+ scope = RT_SCOPE_UNIVERSE;
+ if (!ipv4_is_zeronet(ip_hdr(skb)->saddr)) {
+ fl4.flowi4_oif = 0;
+ fl4.flowi4_iif = net->loopback_dev->ifindex;
+ fl4.daddr = ip_hdr(skb)->saddr;
+ fl4.saddr = 0;
+ fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos);
+ fl4.flowi4_scope = scope;
+ fl4.flowi4_mark = IN_DEV_SRC_VMARK(in_dev) ? skb->mark : 0;
+ if (!fib_lookup(net, &fl4, &res))
+ return FIB_RES_PREFSRC(net, res);
+ } else {
+ scope = RT_SCOPE_LINK;
+ }
+
+ return inet_select_addr(dev, ip_hdr(skb)->saddr, scope);
}
/* Given (packet source, input interface) and optional (dst, oif, tos):