[PATCH net] netlink: specs: mptcp: fix port endianness

[PATCH net] netlink: specs: mptcp: fix port endianness

[Asbjørn Sloth Tønnesen]

The MPTCP port attribute is in host endianness, but was documented
as big-endian in the ynl specification.

Below are two examples from net/mptcp/pm_netlink.c showing that the
attribute is converted to/from host endianness for use with netlink.

Import from netlink:
  addr->port = htons(nla_get_u16(tb[MPTCP_PM_ADDR_ATTR_PORT]))

Export to netlink:
  nla_put_u16(skb, MPTCP_PM_ADDR_ATTR_PORT, ntohs(addr->port))

Where addr->port is defined as __be16.

No functional change intended.

Fixes: bc8aeb2045e2 ("Documentation: netlink: add a YAML spec for mptcp")
Signed-off-by: Asbjørn Sloth Tønnesen <ast@fiberby.net>
---
 Documentation/netlink/specs/mptcp_pm.yaml | 1 -
 1 file changed, 1 deletion(-)

diff --git a/Documentation/netlink/specs/mptcp_pm.yaml b/Documentation/netlink/specs/mptcp_pm.yaml
index af525ed29792..30d8342cacc8 100644
--- a/Documentation/netlink/specs/mptcp_pm.yaml
+++ b/Documentation/netlink/specs/mptcp_pm.yaml
@@ -109,7 +109,6 @@ attribute-sets:
       -
         name: port
         type: u16
-        byte-order: big-endian
       -
         name: flags
         type: u32
-- 
2.45.2

Re: [PATCH net] netlink: specs: mptcp: fix port endianness

[Davide Caratti]

hello Asbjørn,

On Wed, Sep 11, 2024 at 09:10:02AM +0000, Asbjørn Sloth Tønnesen wrote:
> The MPTCP port attribute is in host endianness, but was documented
> as big-endian in the ynl specification.
> 
> Below are two examples from net/mptcp/pm_netlink.c showing that the
> attribute is converted to/from host endianness for use with netlink.
> 
> Import from netlink:
>   addr->port = htons(nla_get_u16(tb[MPTCP_PM_ADDR_ATTR_PORT]))
> 
> Export to netlink:
>   nla_put_u16(skb, MPTCP_PM_ADDR_ATTR_PORT, ntohs(addr->port))
> 
> Where addr->port is defined as __be16.
> 
> No functional change intended.
> 
> Fixes: bc8aeb2045e2 ("Documentation: netlink: add a YAML spec for mptcp")
> Signed-off-by: Asbjørn Sloth Tønnesen <ast@fiberby.net>

not sure why we are doing addresses in network byte order
and ports in host byte order for endpoints. But it's like this since the
very beginning, so this host ordering in spec is correct.

Reviewed-by: Davide Caratti <dcaratti@redhat.com>

Re: [PATCH net] netlink: specs: mptcp: fix port endianness

[Matthieu Baerts]

Hi Asbjørn,

On 11/09/2024 11:10, Asbjørn Sloth Tønnesen wrote:
> The MPTCP port attribute is in host endianness, but was documented
> as big-endian in the ynl specification.
> 
> Below are two examples from net/mptcp/pm_netlink.c showing that the
> attribute is converted to/from host endianness for use with netlink.
> 
> Import from netlink:
>   addr->port = htons(nla_get_u16(tb[MPTCP_PM_ADDR_ATTR_PORT]))
> 
> Export to netlink:
>   nla_put_u16(skb, MPTCP_PM_ADDR_ATTR_PORT, ntohs(addr->port))
> 
> Where addr->port is defined as __be16.
> 
> No functional change intended.

Good catch. Indeed, this port attribute is supposed to be in host
endianness.

Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>

This patch can be applied in netdev directly.

Cheers,
Matt
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Sponsored by the NGI0 Core fund.

Re: [PATCH net] netlink: specs: mptcp: fix port endianness

[patchwork-bot+netdevbpf]

Hello:

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

On Wed, 11 Sep 2024 09:10:02 +0000 you wrote:
> The MPTCP port attribute is in host endianness, but was documented
> as big-endian in the ynl specification.
> 
> Below are two examples from net/mptcp/pm_netlink.c showing that the
> attribute is converted to/from host endianness for use with netlink.
> 
> Import from netlink:
>   addr->port = htons(nla_get_u16(tb[MPTCP_PM_ADDR_ATTR_PORT]))
> 
> [...]

Here is the summary with links:
  - [net] netlink: specs: mptcp: fix port endianness
    https://git.kernel.org/netdev/net/c/09a45a555379

You are awesome, thank you!
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