[PATCH net-next 0/4] Unmask upper DSCP bits - part 3

[PATCH net-next 0/4] Unmask upper DSCP bits - part 3

[Ido Schimmel]

tl;dr - This patchset continues to unmask the upper DSCP bits in the
IPv4 flow key in preparation for allowing IPv4 FIB rules to match on
DSCP. No functional changes are expected.

The TOS field in the IPv4 flow key ('flowi4_tos') is used during FIB
lookup to match against the TOS selector in FIB rules and routes.

It is currently impossible for user space to configure FIB rules that
match on the DSCP value as the upper DSCP bits are either masked in the
various call sites that initialize the IPv4 flow key or along the path
to the FIB core.

In preparation for adding a DSCP selector to IPv4 and IPv6 FIB rules, we
need to make sure the entire DSCP value is present in the IPv4 flow key.
This patchset continues to unmask the upper DSCP bits, but this time in
the output route path, specifically in the callers of
ip_route_output_ports().

The next patchset (last) will handle the callers of
ip_route_output_key(). Split from this patchset to avoid going over the
15 patches limit.

No functional changes are expected as commit 1fa3314c14c6 ("ipv4:
Centralize TOS matching") moved the masking of the upper DSCP bits to
the core where 'flowi4_tos' is matched against the TOS selector.

Ido Schimmel (4):
  ipv4: Unmask upper DSCP bits in __ip_queue_xmit()
  ipv4: ipmr: Unmask upper DSCP bits in ipmr_queue_xmit()
  ip6_tunnel: Unmask upper DSCP bits in ip4ip6_err()
  ipv6: sit: Unmask upper DSCP bits in ipip6_tunnel_bind_dev()

 net/ipv4/ip_output.c  | 2 +-
 net/ipv4/ipmr.c       | 4 ++--
 net/ipv6/ip6_tunnel.c | 7 +++++--
 net/ipv6/sit.c        | 2 +-
 4 files changed, 9 insertions(+), 6 deletions(-)

-- 
2.46.0

[PATCH net-next 1/4] ipv4: Unmask upper DSCP bits in __ip_queue_xmit()

[Ido Schimmel]

The function is passed the full DS field in its 'tos' argument by its
two callers. It then masks the upper DSCP bits using RT_TOS() when
passing it to ip_route_output_ports().

Unmask the upper DSCP bits when passing 'tos' to ip_route_output_ports()
so that in the future it could perform the FIB lookup according to the
full DSCP value.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
---
 net/ipv4/ip_output.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index eea443b7f65e..49811c9281d4 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -494,7 +494,7 @@ int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
 					   inet->inet_dport,
 					   inet->inet_sport,
 					   sk->sk_protocol,
-					   RT_TOS(tos),
+					   tos & INET_DSCP_MASK,
 					   sk->sk_bound_dev_if);
 		if (IS_ERR(rt))
 			goto no_route;
-- 
2.46.0

Re: [PATCH net-next 1/4] ipv4: Unmask upper DSCP bits in __ip_queue_xmit()

[Guillaume Nault]

On Tue, Sep 03, 2024 at 04:53:24PM +0300, Ido Schimmel wrote:
> The function is passed the full DS field in its 'tos' argument by its
> two callers. It then masks the upper DSCP bits using RT_TOS() when
> passing it to ip_route_output_ports().
> 
> Unmask the upper DSCP bits when passing 'tos' to ip_route_output_ports()
> so that in the future it could perform the FIB lookup according to the
> full DSCP value.

Reviewed-by: Guillaume Nault <gnault@redhat.com>

[PATCH net-next 2/4] ipv4: ipmr: Unmask upper DSCP bits in ipmr_queue_xmit()

[Ido Schimmel]

Unmask the upper DSCP bits when calling ip_route_output_ports() so that
in the future it could perform the FIB lookup according to the full DSCP
value.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
---
 net/ipv4/ipmr.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index f1a43199551b..089864c6a35e 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -1869,7 +1869,7 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
 					   vif->remote, vif->local,
 					   0, 0,
 					   IPPROTO_IPIP,
-					   RT_TOS(iph->tos), vif->link);
+					   iph->tos & INET_DSCP_MASK, vif->link);
 		if (IS_ERR(rt))
 			goto out_free;
 		encap = sizeof(struct iphdr);
@@ -1877,7 +1877,7 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
 		rt = ip_route_output_ports(net, &fl4, NULL, iph->daddr, 0,
 					   0, 0,
 					   IPPROTO_IPIP,
-					   RT_TOS(iph->tos), vif->link);
+					   iph->tos & INET_DSCP_MASK, vif->link);
 		if (IS_ERR(rt))
 			goto out_free;
 	}
-- 
2.46.0

Re: [PATCH net-next 2/4] ipv4: ipmr: Unmask upper DSCP bits in ipmr_queue_xmit()

[Guillaume Nault]

On Tue, Sep 03, 2024 at 04:53:25PM +0300, Ido Schimmel wrote:
> Unmask the upper DSCP bits when calling ip_route_output_ports() so that
> in the future it could perform the FIB lookup according to the full DSCP
> value.

Reviewed-by: Guillaume Nault <gnault@redhat.com>

[PATCH net-next 3/4] ip6_tunnel: Unmask upper DSCP bits in ip4ip6_err()

[Ido Schimmel]

Unmask the upper DSCP bits when calling ip_route_output_ports() so that
in the future it could perform the FIB lookup according to the full DSCP
value.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
---
 net/ipv6/ip6_tunnel.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index ec51ab5063e8..b60e13c42bca 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -53,6 +53,7 @@
 #include <net/net_namespace.h>
 #include <net/netns/generic.h>
 #include <net/dst_metadata.h>
+#include <net/inet_dscp.h>
 
 MODULE_AUTHOR("Ville Nuorvala");
 MODULE_DESCRIPTION("IPv6 tunneling device");
@@ -608,7 +609,8 @@ ip4ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 
 	/* Try to guess incoming interface */
 	rt = ip_route_output_ports(dev_net(skb->dev), &fl4, NULL, eiph->saddr,
-				   0, 0, 0, IPPROTO_IPIP, RT_TOS(eiph->tos), 0);
+				   0, 0, 0, IPPROTO_IPIP,
+				   eiph->tos & INET_DSCP_MASK, 0);
 	if (IS_ERR(rt))
 		goto out;
 
@@ -619,7 +621,8 @@ ip4ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 	if (rt->rt_flags & RTCF_LOCAL) {
 		rt = ip_route_output_ports(dev_net(skb->dev), &fl4, NULL,
 					   eiph->daddr, eiph->saddr, 0, 0,
-					   IPPROTO_IPIP, RT_TOS(eiph->tos), 0);
+					   IPPROTO_IPIP,
+					   eiph->tos & INET_DSCP_MASK, 0);
 		if (IS_ERR(rt) || rt->dst.dev->type != ARPHRD_TUNNEL6) {
 			if (!IS_ERR(rt))
 				ip_rt_put(rt);
-- 
2.46.0

Re: [PATCH net-next 3/4] ip6_tunnel: Unmask upper DSCP bits in ip4ip6_err()

[Guillaume Nault]

On Tue, Sep 03, 2024 at 04:53:26PM +0300, Ido Schimmel wrote:
> Unmask the upper DSCP bits when calling ip_route_output_ports() so that
> in the future it could perform the FIB lookup according to the full DSCP
> value.

Reviewed-by: Guillaume Nault <gnault@redhat.com>

[PATCH net-next 4/4] ipv6: sit: Unmask upper DSCP bits in ipip6_tunnel_bind_dev()

[Ido Schimmel]

Unmask the upper DSCP bits when calling ip_route_output_ports() so that
in the future it could perform the FIB lookup according to the full DSCP
value.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
---
 net/ipv6/sit.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 16b90a24c9ba..39bd8951bfca 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -1112,7 +1112,7 @@ static void ipip6_tunnel_bind_dev(struct net_device *dev)
 							  iph->daddr, iph->saddr,
 							  0, 0,
 							  IPPROTO_IPV6,
-							  RT_TOS(iph->tos),
+							  iph->tos & INET_DSCP_MASK,
 							  tunnel->parms.link);
 
 		if (!IS_ERR(rt)) {
-- 
2.46.0

Re: [PATCH net-next 4/4] ipv6: sit: Unmask upper DSCP bits in ipip6_tunnel_bind_dev()

[Guillaume Nault]

On Tue, Sep 03, 2024 at 04:53:27PM +0300, Ido Schimmel wrote:
> Unmask the upper DSCP bits when calling ip_route_output_ports() so that
> in the future it could perform the FIB lookup according to the full DSCP
> value.

Reviewed-by: Guillaume Nault <gnault@redhat.com>

Re: [PATCH net-next 0/4] Unmask upper DSCP bits - part 3

[David Ahern]

On 9/3/24 7:53 AM, Ido Schimmel wrote:
> tl;dr - This patchset continues to unmask the upper DSCP bits in the
> IPv4 flow key in preparation for allowing IPv4 FIB rules to match on
> DSCP. No functional changes are expected.
> 
> The TOS field in the IPv4 flow key ('flowi4_tos') is used during FIB
> lookup to match against the TOS selector in FIB rules and routes.
> 
> It is currently impossible for user space to configure FIB rules that
> match on the DSCP value as the upper DSCP bits are either masked in the
> various call sites that initialize the IPv4 flow key or along the path
> to the FIB core.
> 
> In preparation for adding a DSCP selector to IPv4 and IPv6 FIB rules, we
> need to make sure the entire DSCP value is present in the IPv4 flow key.
> This patchset continues to unmask the upper DSCP bits, but this time in
> the output route path, specifically in the callers of
> ip_route_output_ports().
> 
> The next patchset (last) will handle the callers of
> ip_route_output_key(). Split from this patchset to avoid going over the
> 15 patches limit.
> 
> No functional changes are expected as commit 1fa3314c14c6 ("ipv4:
> Centralize TOS matching") moved the masking of the upper DSCP bits to
> the core where 'flowi4_tos' is matched against the TOS selector.
> 
> Ido Schimmel (4):
>   ipv4: Unmask upper DSCP bits in __ip_queue_xmit()
>   ipv4: ipmr: Unmask upper DSCP bits in ipmr_queue_xmit()
>   ip6_tunnel: Unmask upper DSCP bits in ip4ip6_err()
>   ipv6: sit: Unmask upper DSCP bits in ipip6_tunnel_bind_dev()
> 
>  net/ipv4/ip_output.c  | 2 +-
>  net/ipv4/ipmr.c       | 4 ++--
>  net/ipv6/ip6_tunnel.c | 7 +++++--
>  net/ipv6/sit.c        | 2 +-
>  4 files changed, 9 insertions(+), 6 deletions(-)
> 

For the set:

Reviewed-by: David Ahern <dsahern@kernel.org>

Re: [PATCH net-next 0/4] Unmask upper DSCP bits - part 3

[patchwork-bot+netdevbpf]

Hello:

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

On Tue, 3 Sep 2024 16:53:23 +0300 you wrote:
> tl;dr - This patchset continues to unmask the upper DSCP bits in the
> IPv4 flow key in preparation for allowing IPv4 FIB rules to match on
> DSCP. No functional changes are expected.
> 
> The TOS field in the IPv4 flow key ('flowi4_tos') is used during FIB
> lookup to match against the TOS selector in FIB rules and routes.
> 
> [...]

Here is the summary with links:
  - [net-next,1/4] ipv4: Unmask upper DSCP bits in __ip_queue_xmit()
    https://git.kernel.org/netdev/net-next/c/71f1fea4f65d
  - [net-next,2/4] ipv4: ipmr: Unmask upper DSCP bits in ipmr_queue_xmit()
    https://git.kernel.org/netdev/net-next/c/97edbbaad303
  - [net-next,3/4] ip6_tunnel: Unmask upper DSCP bits in ip4ip6_err()
    https://git.kernel.org/netdev/net-next/c/de1fb3e8b053
  - [net-next,4/4] ipv6: sit: Unmask upper DSCP bits in ipip6_tunnel_bind_dev()
    https://git.kernel.org/netdev/net-next/c/c9a1e2629d10

You are awesome, thank you!
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