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Commit a210d01a authored by Julian Anastasov's avatar Julian Anastasov Committed by David S. Miller
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ipv4: Loosen source address check on IPv4 output 



ip_route_output() contains a check to make sure that no flows with
non-local source IP addresses are routed. This obviously makes using
such addresses impossible.

This patch introduces a flowi flag which makes omitting this check
possible. The new flag provides a way of handling transparent and
non-transparent connections differently.

Signed-off-by: default avatarJulian Anastasov <ja@ssi.bg>
Signed-off-by: default avatarKOVACS Krisztian <hidden@sch.bme.hu>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 4edd87ad

include/net/flow.h

+2 −0
Original line number Diff line number Diff line
@@ -47,6 +47,8 @@ struct flowi { 
#define fl4_scope	nl_u.ip4_u.scope



	__u8	proto;

	__u8	flags;

#define FLOWI_FLAG_ANYSRC 0x01

	union {

		struct {

			__be16	sport;

net/ipv4/route.c

+13 −7
Original line number Diff line number Diff line
@@ -2361,11 +2361,6 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp, 
		    ipv4_is_zeronet(oldflp->fl4_src))

			goto out;



		/* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */

		dev_out = ip_dev_find(net, oldflp->fl4_src);

		if (dev_out == NULL)

			goto out;



		/* I removed check for oif == dev_out->oif here.

		   It was wrong for two reasons:

		   1. ip_dev_find(net, saddr) can return wrong iface, if saddr
@@ -2377,6 +2372,11 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp, 
		if (oldflp->oif == 0

		    && (ipv4_is_multicast(oldflp->fl4_dst) ||

			oldflp->fl4_dst == htonl(0xFFFFFFFF))) {

			/* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */

			dev_out = ip_dev_find(net, oldflp->fl4_src);

			if (dev_out == NULL)

				goto out;



			/* Special hack: user can direct multicasts

			   and limited broadcast via necessary interface

			   without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
@@ -2395,10 +2395,16 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp, 
			fl.oif = dev_out->ifindex;

			goto make_route;

		}

		if (dev_out)



		if (!(oldflp->flags & FLOWI_FLAG_ANYSRC)) {

			/* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */

			dev_out = ip_dev_find(net, oldflp->fl4_src);

			if (dev_out == NULL)

				goto out;

			dev_put(dev_out);

			dev_out = NULL;

		}

	}





	if (oldflp->oif) {