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Commit a207a4b2 authored by David S. Miller's avatar David S. Miller
Browse files

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: default avatarDavid S. Miller <davem@davemloft.net>
parent 58050fce

net/ipv4/fib_frontend.c

+21 −13
Original line number Original line Diff line number Diff line
@@ -185,28 +185,36 @@ __be32 fib_compute_spec_dst(struct sk_buff *skb) 
	struct net_device *dev = skb->dev;

	struct net_device *dev = skb->dev;

	struct in_device *in_dev;

	struct in_device *in_dev;

	struct fib_result res;

	struct fib_result res;

	struct rtable *rt;

	struct flowi4 fl4;

	struct flowi4 fl4;

	struct net *net;

	struct net *net;

	int scope;





	if (skb->pkt_type != PACKET_BROADCAST &&

	rt = skb_rtable(skb);

	    skb->pkt_type != PACKET_MULTICAST)

	if (!(rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)))

		return ip_hdr(skb)->daddr;

		return ip_hdr(skb)->daddr;





	in_dev = __in_dev_get_rcu(dev);

	in_dev = __in_dev_get_rcu(dev);

	BUG_ON(!in_dev);

	BUG_ON(!in_dev);



	net = dev_net(dev);



	scope = RT_SCOPE_UNIVERSE;

	if (!ipv4_is_zeronet(ip_hdr(skb)->saddr)) {

		fl4.flowi4_oif = 0;

		fl4.flowi4_oif = 0;

	fl4.flowi4_iif = 0;

		fl4.flowi4_iif = net->loopback_dev->ifindex;

		fl4.daddr = ip_hdr(skb)->saddr;

		fl4.daddr = ip_hdr(skb)->saddr;

	fl4.saddr = ip_hdr(skb)->daddr;

		fl4.saddr = 0;

		fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos);

		fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos);

	fl4.flowi4_scope = RT_SCOPE_UNIVERSE;

		fl4.flowi4_scope = scope;

		fl4.flowi4_mark = IN_DEV_SRC_VMARK(in_dev) ? skb->mark : 0;

		fl4.flowi4_mark = IN_DEV_SRC_VMARK(in_dev) ? skb->mark : 0;



	net = dev_net(dev);

		if (!fib_lookup(net, &fl4, &res))

		if (!fib_lookup(net, &fl4, &res))

			return FIB_RES_PREFSRC(net, res);

			return FIB_RES_PREFSRC(net, res);

	else

	} else {

		return inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);

		scope = RT_SCOPE_LINK;

	}



	return inet_select_addr(dev, ip_hdr(skb)->saddr, scope);

}

}





/* Given (packet source, input interface) and optional (dst, oif, tos):

/* Given (packet source, input interface) and optional (dst, oif, tos):