Commit 0e9a7095 authored by Peter Dawson's avatar Peter Dawson Committed by David S. Miller
Browse files

ip6_tunnel, ip6_gre: fix setting of DSCP on encapsulated packets 

This fix addresses two problems in the way the DSCP field is formulated
 on the encapsulating header of IPv6 tunnels.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=195661



1) The IPv6 tunneling code was manipulating the DSCP field of the
 encapsulating packet using the 32b flowlabel. Since the flowlabel is
 only the lower 20b it was incorrect to assume that the upper 12b
 containing the DSCP and ECN fields would remain intact when formulating
 the encapsulating header. This fix handles the 'inherit' and
 'fixed-value' DSCP cases explicitly using the extant dsfield u8 variable.

2) The use of INET_ECN_encapsulate(0, dsfield) in ip6_tnl_xmit was
 incorrect and resulted in the DSCP value always being set to 0.

Commit 90427ef5 ("ipv6: fix flow labels when the traffic class
 is non-0") caused the regression by masking out the flowlabel
 which exposed the incorrect handling of the DSCP portion of the
 flowlabel in ip6_tunnel and ip6_gre.

Fixes: 90427ef5 ("ipv6: fix flow labels when the traffic class is non-0")
Signed-off-by: default avatarPeter Dawson <peter.a.dawson@boeing.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 804ec7eb

net/ipv6/ip6_gre.c

+7 −6
Original line number Diff line number Diff line
@@ -537,11 +537,10 @@ static inline int ip6gre_xmit_ipv4(struct sk_buff *skb, struct net_device *dev) 


	memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));



	dsfield = ipv4_get_dsfield(iph);



	if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)

		fl6.flowlabel |= htonl((__u32)iph->tos << IPV6_TCLASS_SHIFT)

					  & IPV6_TCLASS_MASK;

		dsfield = ipv4_get_dsfield(iph);

	else

		dsfield = ip6_tclass(t->parms.flowinfo);

	if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)

		fl6.flowi6_mark = skb->mark;

	else
@@ -598,9 +597,11 @@ static inline int ip6gre_xmit_ipv6(struct sk_buff *skb, struct net_device *dev) 


	memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));



	dsfield = ipv6_get_dsfield(ipv6h);

	if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)

		fl6.flowlabel |= (*(__be32 *) ipv6h & IPV6_TCLASS_MASK);

		dsfield = ipv6_get_dsfield(ipv6h);

	else

		dsfield = ip6_tclass(t->parms.flowinfo);



	if (t->parms.flags & IP6_TNL_F_USE_ORIG_FLOWLABEL)

		fl6.flowlabel |= ip6_flowlabel(ipv6h);

	if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)

net/ipv6/ip6_tunnel.c

+13 −8
Original line number Diff line number Diff line
@@ -1196,7 +1196,7 @@ route_lookup: 
	skb_push(skb, sizeof(struct ipv6hdr));

	skb_reset_network_header(skb);

	ipv6h = ipv6_hdr(skb);

	ip6_flow_hdr(ipv6h, INET_ECN_encapsulate(0, dsfield),

	ip6_flow_hdr(ipv6h, dsfield,

		     ip6_make_flowlabel(net, skb, fl6->flowlabel, true, fl6));

	ipv6h->hop_limit = hop_limit;

	ipv6h->nexthdr = proto;
@@ -1231,8 +1231,6 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) 
	if (tproto != IPPROTO_IPIP && tproto != 0)

		return -1;



	dsfield = ipv4_get_dsfield(iph);



	if (t->parms.collect_md) {

		struct ip_tunnel_info *tun_info;

		const struct ip_tunnel_key *key;
@@ -1246,6 +1244,7 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) 
		fl6.flowi6_proto = IPPROTO_IPIP;

		fl6.daddr = key->u.ipv6.dst;

		fl6.flowlabel = key->label;

		dsfield = ip6_tclass(key->label);

	} else {

		if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))

			encap_limit = t->parms.encap_limit;
@@ -1254,8 +1253,9 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) 
		fl6.flowi6_proto = IPPROTO_IPIP;



		if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)

			fl6.flowlabel |= htonl((__u32)iph->tos << IPV6_TCLASS_SHIFT)

					 & IPV6_TCLASS_MASK;

			dsfield = ipv4_get_dsfield(iph);

		else

			dsfield = ip6_tclass(t->parms.flowinfo);

		if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)

			fl6.flowi6_mark = skb->mark;

		else
@@ -1267,6 +1267,8 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) 
	if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP6))

		return -1;



	dsfield = INET_ECN_encapsulate(dsfield, ipv4_get_dsfield(iph));



	skb_set_inner_ipproto(skb, IPPROTO_IPIP);



	err = ip6_tnl_xmit(skb, dev, dsfield, &fl6, encap_limit, &mtu,
@@ -1300,8 +1302,6 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) 
	    ip6_tnl_addr_conflict(t, ipv6h))

		return -1;



	dsfield = ipv6_get_dsfield(ipv6h);



	if (t->parms.collect_md) {

		struct ip_tunnel_info *tun_info;

		const struct ip_tunnel_key *key;
@@ -1315,6 +1315,7 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) 
		fl6.flowi6_proto = IPPROTO_IPV6;

		fl6.daddr = key->u.ipv6.dst;

		fl6.flowlabel = key->label;

		dsfield = ip6_tclass(key->label);

	} else {

		offset = ip6_tnl_parse_tlv_enc_lim(skb, skb_network_header(skb));

		/* ip6_tnl_parse_tlv_enc_lim() might have reallocated skb->head */
@@ -1337,7 +1338,9 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) 
		fl6.flowi6_proto = IPPROTO_IPV6;



		if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)

			fl6.flowlabel |= (*(__be32 *)ipv6h & IPV6_TCLASS_MASK);

			dsfield = ipv6_get_dsfield(ipv6h);

		else

			dsfield = ip6_tclass(t->parms.flowinfo);

		if (t->parms.flags & IP6_TNL_F_USE_ORIG_FLOWLABEL)

			fl6.flowlabel |= ip6_flowlabel(ipv6h);

		if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
@@ -1351,6 +1354,8 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) 
	if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP6))

		return -1;



	dsfield = INET_ECN_encapsulate(dsfield, ipv6_get_dsfield(ipv6h));



	skb_set_inner_ipproto(skb, IPPROTO_IPV6);



	err = ip6_tnl_xmit(skb, dev, dsfield, &fl6, encap_limit, &mtu,

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