[PATCH v3 net 0/4] Do not use RT_TOS for IPv6 flowlabel

[PATCH v3 net 0/4] Do not use RT_TOS for IPv6 flowlabel

[Matthias May]

According to Guillaume Nault RT_TOS should never be used for IPv6.

Quote:
RT_TOS() is an old macro used to interprete IPv4 TOS as described in
the obsolete RFC 1349. It's conceptually wrong to use it even in IPv4
code, although, given the current state of the code, most of the
existing calls have no consequence.

But using RT_TOS() in IPv6 code is always a bug: IPv6 never had a "TOS"
field to be interpreted the RFC 1349 way. There's no historical
compatibility to worry about.

---
v1 -> v2:
 - Fix spacing of "Fixes" tag.
 - Add missing CCs
v2 -> v3:
 - Add the info from the cover to the actual patch message (Guillaume Nault)

Matthias May (4):
  geneve: do not use RT_TOS for IPv6 flowlabel
  vxlan: do not use RT_TOS for IPv6 flowlabel
  mlx5: do not use RT_TOS for IPv6 flowlabel
  ipv6: do not use RT_TOS for IPv6 flowlabel

 drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c | 4 ++--
 drivers/net/geneve.c                                | 3 +--
 drivers/net/vxlan/vxlan_core.c                      | 2 +-
 net/ipv6/ip6_output.c                               | 3 +--
 4 files changed, 5 insertions(+), 7 deletions(-)

-- 
2.35.1

[PATCH v3 net 1/4] geneve: do not use RT_TOS for IPv6 flowlabel

[Matthias May]

According to Guillaume Nault RT_TOS should never be used for IPv6.

Quote:
RT_TOS() is an old macro used to interprete IPv4 TOS as described in
the obsolete RFC 1349. It's conceptually wrong to use it even in IPv4
code, although, given the current state of the code, most of the
existing calls have no consequence.

But using RT_TOS() in IPv6 code is always a bug: IPv6 never had a "TOS"
field to be interpreted the RFC 1349 way. There's no historical
compatibility to worry about.

Fixes: 3a56f86f1be6 ("geneve: handle ipv6 priority like ipv4 tos")
Acked-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Matthias May <matthias.may@westermo.com>
---
v1 -> v2:
 - Fix spacing of "Fixes" tag.
 - Add missing CCs
v2 -> v3:
 - Add the info from the cover to the actual patch message (Guillaume Nault)
 - Correct length of fixes-tag from 13 to 12 characters (Guillaume Nault)
---
 drivers/net/geneve.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index 4c380c06f178..e1a4480e6f17 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -877,8 +877,7 @@ static struct dst_entry *geneve_get_v6_dst(struct sk_buff *skb,
 		use_cache = false;
 	}
 
-	fl6->flowlabel = ip6_make_flowinfo(RT_TOS(prio),
-					   info->key.label);
+	fl6->flowlabel = ip6_make_flowinfo(prio, info->key.label);
 	dst_cache = (struct dst_cache *)&info->dst_cache;
 	if (use_cache) {
 		dst = dst_cache_get_ip6(dst_cache, &fl6->saddr);
-- 
2.35.1

[PATCH v3 net 2/4] vxlan: do not use RT_TOS for IPv6 flowlabel

[Matthias May]

According to Guillaume Nault RT_TOS should never be used for IPv6.

Quote:
RT_TOS() is an old macro used to interprete IPv4 TOS as described in
the obsolete RFC 1349. It's conceptually wrong to use it even in IPv4
code, although, given the current state of the code, most of the
existing calls have no consequence.

But using RT_TOS() in IPv6 code is always a bug: IPv6 never had a "TOS"
field to be interpreted the RFC 1349 way. There's no historical
compatibility to worry about.

Fixes: 1400615d64cf ("vxlan: allow setting ipv6 traffic class")
Acked-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Matthias May <matthias.may@westermo.com>
---
v1 -> v2:
 - Fix spacing of "Fixes" tag.
 - Add missing CCs
v2 -> v3:
 - Add the info from the cover to the actual patch message (Guillaume Nault)
---
 drivers/net/vxlan/vxlan_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index 265d4a0245e7..797585fbb004 100644
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -2320,7 +2320,7 @@ static struct dst_entry *vxlan6_get_route(struct vxlan_dev *vxlan,
 	fl6.flowi6_oif = oif;
 	fl6.daddr = *daddr;
 	fl6.saddr = *saddr;
-	fl6.flowlabel = ip6_make_flowinfo(RT_TOS(tos), label);
+	fl6.flowlabel = ip6_make_flowinfo(tos, label);
 	fl6.flowi6_mark = skb->mark;
 	fl6.flowi6_proto = IPPROTO_UDP;
 	fl6.fl6_dport = dport;
-- 
2.35.1

[PATCH v3 net 3/4] mlx5: do not use RT_TOS for IPv6 flowlabel

[Matthias May]

According to Guillaume Nault RT_TOS should never be used for IPv6.

Quote:
RT_TOS() is an old macro used to interprete IPv4 TOS as described in
the obsolete RFC 1349. It's conceptually wrong to use it even in IPv4
code, although, given the current state of the code, most of the
existing calls have no consequence.

But using RT_TOS() in IPv6 code is always a bug: IPv6 never had a "TOS"
field to be interpreted the RFC 1349 way. There's no historical
compatibility to worry about.

Fixes: ce99f6b97fcd ("net/mlx5e: Support SRIOV TC encapsulation offloads for IPv6 tunnels")
Acked-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Matthias May <matthias.may@westermo.com>
---
v1 -> v2:
 - Fix spacing of "Fixes" tag.
 - Add missing CCs
v2 -> v3:
 - Add the info from the cover to the actual patch message (Guillaume Nault)
---
 drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c
index d87bbb0be7c8..e6f64d890fb3 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c
@@ -506,7 +506,7 @@ int mlx5e_tc_tun_create_header_ipv6(struct mlx5e_priv *priv,
 	int err;
 
 	attr.ttl = tun_key->ttl;
-	attr.fl.fl6.flowlabel = ip6_make_flowinfo(RT_TOS(tun_key->tos), tun_key->label);
+	attr.fl.fl6.flowlabel = ip6_make_flowinfo(tun_key->tos, tun_key->label);
 	attr.fl.fl6.daddr = tun_key->u.ipv6.dst;
 	attr.fl.fl6.saddr = tun_key->u.ipv6.src;
 
@@ -620,7 +620,7 @@ int mlx5e_tc_tun_update_header_ipv6(struct mlx5e_priv *priv,
 
 	attr.ttl = tun_key->ttl;
 
-	attr.fl.fl6.flowlabel = ip6_make_flowinfo(RT_TOS(tun_key->tos), tun_key->label);
+	attr.fl.fl6.flowlabel = ip6_make_flowinfo(tun_key->tos, tun_key->label);
 	attr.fl.fl6.daddr = tun_key->u.ipv6.dst;
 	attr.fl.fl6.saddr = tun_key->u.ipv6.src;
 
-- 
2.35.1

[PATCH v3 net 4/4] ipv6: do not use RT_TOS for IPv6 flowlabel

[Matthias May]

According to Guillaume Nault RT_TOS should never be used for IPv6.

Quote:
RT_TOS() is an old macro used to interprete IPv4 TOS as described in
the obsolete RFC 1349. It's conceptually wrong to use it even in IPv4
code, although, given the current state of the code, most of the
existing calls have no consequence.

But using RT_TOS() in IPv6 code is always a bug: IPv6 never had a "TOS"
field to be interpreted the RFC 1349 way. There's no historical
compatibility to worry about.

Fixes: 571912c69f0e ("net: UDP tunnel encapsulation module for tunnelling different protocols like MPLS, IP, NSH etc.")
Acked-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Matthias May <matthias.may@westermo.com>
---
v1 -> v2:
 - Fix spacing of "Fixes" tag.
 - Add missing CCs
v2 -> v3:
 - Add the info from the cover to the actual patch message (Guillaume Nault)
---
 net/ipv6/ip6_output.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 77e3f5970ce4..ec62f472aa1c 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1311,8 +1311,7 @@ struct dst_entry *ip6_dst_lookup_tunnel(struct sk_buff *skb,
 	fl6.daddr = info->key.u.ipv6.dst;
 	fl6.saddr = info->key.u.ipv6.src;
 	prio = info->key.tos;
-	fl6.flowlabel = ip6_make_flowinfo(RT_TOS(prio),
-					  info->key.label);
+	fl6.flowlabel = ip6_make_flowinfo(prio, info->key.label);
 
 	dst = ipv6_stub->ipv6_dst_lookup_flow(net, sock->sk, &fl6,
 					      NULL);
-- 
2.35.1

Re: [PATCH v3 net 0/4] Do not use RT_TOS for IPv6 flowlabel

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net.git (master)
by Jakub Kicinski <kuba@kernel.org>:

On Fri, 5 Aug 2022 21:19:02 +0200 you wrote:
> According to Guillaume Nault RT_TOS should never be used for IPv6.
> 
> Quote:
> RT_TOS() is an old macro used to interprete IPv4 TOS as described in
> the obsolete RFC 1349. It's conceptually wrong to use it even in IPv4
> code, although, given the current state of the code, most of the
> existing calls have no consequence.
> 
> [...]

Here is the summary with links:
  - [v3,net,1/4] geneve: do not use RT_TOS for IPv6 flowlabel
    https://git.kernel.org/netdev/net/c/ca2bb69514a8
  - [v3,net,2/4] vxlan: do not use RT_TOS for IPv6 flowlabel
    https://git.kernel.org/netdev/net/c/e488d4f5d6e4
  - [v3,net,3/4] mlx5: do not use RT_TOS for IPv6 flowlabel
    https://git.kernel.org/netdev/net/c/bcb0da7fffee
  - [v3,net,4/4] ipv6: do not use RT_TOS for IPv6 flowlabel
    https://git.kernel.org/netdev/net/c/ab7e2e0dfa5d

You are awesome, thank you!
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