Re: [PATCH bpf-next v3 3/7] net: document inet[6]_lookup_reuseport sk_state requirements

[Kuniyuki Iwashima]

From: Lorenz Bauer <lmb@xxxxxxxxxxxxx>
Date: Mon, 26 Jun 2023 16:09:00 +0100
> The current implementation was extracted from inet[6]_lhash2_lookup
> in commit 80b373f74f9e ("inet: Extract helper for selecting socket
> from reuseport group") and commit 5df6531292b5 ("inet6: Extract helper
> for selecting socket from reuseport group"). In the original context,
> sk is always in TCP_LISTEN state and so did not have a separate check.
> 
> Add documentation that specifies which sk_state are valid to pass to
> the function.
> 
> Signed-off-by: Lorenz Bauer <lmb@xxxxxxxxxxxxx>
> ---
>  net/ipv4/inet_hashtables.c  | 14 ++++++++++++++
>  net/ipv6/inet6_hashtables.c | 14 ++++++++++++++
>  2 files changed, 28 insertions(+)
> 
> diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
> index 920131e4a65d..91f9210d4e83 100644
> --- a/net/ipv4/inet_hashtables.c
> +++ b/net/ipv4/inet_hashtables.c
> @@ -332,6 +332,20 @@ static inline int compute_score(struct sock *sk, struct net *net,
>  	return score;
>  }
>  
> +/**
> + * inet_lookup_reuseport() - execute reuseport logic on AF_INET socket if necessary.
> + * @net: network namespace.
> + * @sk: AF_INET socket, must be in TCP_LISTEN state for TCP or TCP_CLOSE for UDP.

nit: " or TCP_CLOSE for UDP"

This part should be added in the next patch,
or this patch should be 4th patch.


> + * @skb: context for a potential SK_REUSEPORT program.
> + * @doff: header offset.
> + * @saddr: source address.
> + * @sport: source port.
> + * @daddr: destination address.
> + * @hnum: destination port in host byte order.
> + *
> + * Return: NULL if sk doesn't have SO_REUSEPORT set, otherwise a pointer to
> + *         the selected sock or an error.
> + */
>  struct sock *inet_lookup_reuseport(struct net *net, struct sock *sk,
>  				   struct sk_buff *skb, int doff,
>  				   __be32 saddr, __be16 sport,
> diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c
> index b7c56867314e..208998694ae3 100644
> --- a/net/ipv6/inet6_hashtables.c
> +++ b/net/ipv6/inet6_hashtables.c
> @@ -111,6 +111,20 @@ static inline int compute_score(struct sock *sk, struct net *net,
>  	return score;
>  }
>  
> +/**
> + * inet6_lookup_reuseport() - execute reuseport logic on AF_INET6 socket if necessary.
> + * @net: network namespace.
> + * @sk: AF_INET6 socket, must be in TCP_LISTEN state for TCP or TCP_CLOSE for UDP.
> + * @skb: context for a potential SK_REUSEPORT program.
> + * @doff: header offset.
> + * @saddr: source address.
> + * @sport: source port.
> + * @daddr: destination address.
> + * @hnum: destination port in host byte order.
> + *
> + * Return: NULL if sk doesn't have SO_REUSEPORT set, otherwise a pointer to
> + *         the selected sock or an error.
> + */
>  struct sock *inet6_lookup_reuseport(struct net *net, struct sock *sk,
>  				    struct sk_buff *skb, int doff,
>  				    const struct in6_addr *saddr,
> 
> -- 
> 2.40.1