ip6_tunnel, ip6_gre: fix setting of DSCP on encapsulated packets

PATCH Superseded Peter Dawson 2 participants 8 messages May 23, 2017 – May 26, 2017

Subsystems (3)

Networking Network drivers IPv4/IPv6

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Peter Dawson

author

2017-05-23 04:36 UTC #0 lore raw

PATCH 1/1 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.

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.

Fixes https://bugzilla.kernel.org/show_bug.cgi?id=195661

Signed-off-by Peter Dawson <[email protected]>

---
 net/ipv6/ip6_gre.c    | 13 +++++++------
 net/ipv6/ip6_tunnel.c | 21 +++++++++++++--------
 2 files changed, 20 insertions(+), 14 deletions(-)

net/ipv6/ip6_gre.c +7 -6

index 8d128ba..0c5b4caa 100644
@@ -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

index 6eb2ae5..7ae6c50 100644
@@ -1196,7 +1196,7 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield,
 	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,

Signature · 1 line

2.7.4

David Miller

maintainer

2017-05-25 16:11 UTC #1 lore raw

From: Peter Dawson <[email protected]>
Date: Tue, 23 May 2017 14:36:16 +1000

Quoted 1 line

Fixes https://bugzilla.kernel.org/show_bug.cgi?id=195661

This is not the correct way to use the Fixes: tag.

You should specify the commit that introduced the regression between 4.9.x and 4.10.x, and that you are fixing here.

The correct format for the commit references is the 12 initial digits of the SHA1_ID of the commit, followed by a space, followed by the commit log message header line text enclosed in parentheses and double quotes with no line breaks whatsoever.

Thank you.

Peter Dawson

author

2017-05-25 19:46 UTC #2 lore raw

Quoted 6 lines · On Thu, 25 May 2017 12:11:17 -0400 (EDT) David Miller <[email protected]>…

Quoted 1 line
Fixes https://bugzilla.kernel.org/show_bug.cgi?id=195661
This is not the correct way to use the Fixes: tag.
You should specify the commit that introduced the regression between 4.9.x and 4.10.x, and that you are fixing here.

Thanks for your review Dave. I'll resubmit the patch with the following detail and just reference the bugzilla in the main body of the commit comment.

Commit 90427ef5d2a4 ("ipv6: fix flow labels when the traffic class is non-0") caused the regression by masking out the flowlabel which exposed the incorrect the handling of the DSCP portion of the flowlabel in ip6_tunnel and ip6_gre.

David Miller

maintainer

2017-05-25 19:49 UTC #3 lore raw

From: Peter Dawson <[email protected]>
Date: Fri, 26 May 2017 05:46:27 +1000

Quoted 5 lines

Quoted 2 lines · On Thu, 25 May 2017 12:11:17 -0400 (EDT) David Miller <[email protected]>…
Quoted 1 line
Fixes https://bugzilla.kernel.org/show_bug.cgi?id=195661

Quoted 8 lines

Quoted 4 lines
This is not the correct way to use the Fixes: tag.
You should specify the commit that introduced the regression between 4.9.x and 4.10.x, and that you are fixing here.
Thanks for your review Dave. I'll resubmit the patch with the following detail and just reference the bugzilla in the main body of the commit comment.
Commit 90427ef5d2a4 ("ipv6: fix flow labels when the traffic class is non-0") caused the regression by masking out the flowlabel which exposed the incorrect the handling of the DSCP portion of the flowlabel in ip6_tunnel and ip6_gre.

Still not correct, you need to use a "Fixes: " tag of the form:

Fixes 90427ef5d2a4 ("ipv6: fix flow labels when the traffic class is non-0")

And it must appear of the first line of tags, before signoffs and acks, with no empty lines in between.

Thank you.

Peter Dawson

author

2017-05-25 20:08 UTC #4 lore raw

Quoted 6 lines · On Thu, 25 May 2017 15:49:14 -0400 (EDT) David Miller <[email protected]>…

Still not correct, you need to use a "Fixes: " tag of the form:
Fixes 90427ef5d2a4 ("ipv6: fix flow labels when the traffic class is non-0")
And it must appear of the first line of tags, before signoffs and acks, with no empty lines in between.

Here is my proposed commit message in full. Note that the "Fixes" line extends to 78 chars. Is this OK? Thanks

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

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 90427ef5d2a4 caused the regression by masking out the flowlabel
which exposed the incorrect the handling of the DSCP portion of the flowlabel in ip6_tunnel and ip6_gre.

Fixes 90427ef5d2a4 ("ipv6: fix flow labels when the traffic class is non-0")

Signed-off-by Peter Dawson <[email protected]>

David Miller

maintainer

2017-05-25 20:33 UTC #5 lore raw

From: Peter Dawson <[email protected]>
Date: Fri, 26 May 2017 06:08:42 +1000

Quoted 5 lines

Quoted 2 lines · On Thu, 25 May 2017 15:49:14 -0400 (EDT) David Miller <[email protected]>…
Still not correct, you need to use a "Fixes: " tag of the form:

Quoted 7 lines

Quoted 4 lines
Fixes 90427ef5d2a4 ("ipv6: fix flow labels when the traffic class is non-0")
And it must appear of the first line of tags, before signoffs and acks, with no empty lines in between.
Here is my proposed commit message in full. Note that the "Fixes" line extends to 78 chars. Is this OK?

Yes, that looks perfect.

Peter Dawson

author

2017-05-25 20:35 UTC #6 lore raw

PATCH v2 1/1 ip6_tunnel, ip6_gre: fix setting of DSCP on encapsulated packets

In reply to Peter Dawson

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

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 90427ef5d2a4 ("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 90427ef5d2a4 ("ipv6: fix flow labels when the traffic class is non-0")

Signed-off-by Peter Dawson <[email protected]>

---
 net/ipv6/ip6_gre.c    | 13 +++++++------
 net/ipv6/ip6_tunnel.c | 21 +++++++++++++--------
 2 files changed, 20 insertions(+), 14 deletions(-)

net/ipv6/ip6_gre.c +7 -6

index 8d128ba..0c5b4caa 100644
@@ -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

index 6eb2ae5..7ae6c50 100644
@@ -1196,7 +1196,7 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield,
 	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,

Signature · 1 line

2.7.4

David Miller

maintainer Applied

2017-05-26 18:55 UTC #7 lore raw

From: Peter Dawson <[email protected]>
Date: Fri, 26 May 2017 06:35:18 +1000

Quoted 14 lines

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.

Quoted 7 lines

Commit 90427ef5d2a4 ("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 90427ef5d2a4 ("ipv6: fix flow labels when the traffic class is non-0")
Signed-off-by Peter Dawson <[email protected]>

Applied, thanks.