Re: [PATCH net-next 1/2] inet: returns a bool from inet_sk_get_local_port_range()

[Kuniyuki Iwashima <kuniyu@amazon.com>]

From: Eric Dumazet <edumazet@google.com>
Date: Thu, 14 Dec 2023 19:29:38 +0000
> Change inet_sk_get_local_port_range() to return a boolean,
> telling the callers if the port range was provided by
> IP_LOCAL_PORT_RANGE socket option.
> 
> Adds documentation while we are at it.
> 
> Signed-off-by: Eric Dumazet <edumazet@google.com>

Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>


> ---
>  include/net/ip.h                |  2 +-
>  net/ipv4/inet_connection_sock.c | 21 ++++++++++++++++-----
>  2 files changed, 17 insertions(+), 6 deletions(-)
> 
> diff --git a/include/net/ip.h b/include/net/ip.h
> index b31be912489af8b01cc0393a27ffc80b086feaa0..de0c69c57e3cb7485e3d8473bc0b109e4280d2f6 100644
> --- a/include/net/ip.h
> +++ b/include/net/ip.h
> @@ -356,7 +356,7 @@ static inline void inet_get_local_port_range(const struct net *net, int *low, in
>  	*low = range & 0xffff;
>  	*high = range >> 16;
>  }
> -void inet_sk_get_local_port_range(const struct sock *sk, int *low, int *high);
> +bool inet_sk_get_local_port_range(const struct sock *sk, int *low, int *high);
>  
>  #ifdef CONFIG_SYSCTL
>  static inline bool inet_is_local_reserved_port(struct net *net, unsigned short port)
> diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
> index 70be0f6fe879ea671bf6686b04edf32bf5e0d4b6..bd325b029dd12c9fad754ded266ae232ee7ec260 100644
> --- a/net/ipv4/inet_connection_sock.c
> +++ b/net/ipv4/inet_connection_sock.c
> @@ -117,16 +117,25 @@ bool inet_rcv_saddr_any(const struct sock *sk)
>  	return !sk->sk_rcv_saddr;
>  }
>  
> -void inet_sk_get_local_port_range(const struct sock *sk, int *low, int *high)
> +/**
> + *	inet_sk_get_local_port_range - fetch ephemeral ports range
> + *	@sk: socket
> + *	@low: pointer to low port
> + *	@high: pointer to high port
> + *
> + *	Fetch netns port range (/proc/sys/net/ipv4/ip_local_port_range)
> + *	Range can be overridden if socket got IP_LOCAL_PORT_RANGE option.
> + *	Returns true if IP_LOCAL_PORT_RANGE was set on this socket.
> + */
> +bool inet_sk_get_local_port_range(const struct sock *sk, int *low, int *high)
>  {
> -	const struct inet_sock *inet = inet_sk(sk);
> -	const struct net *net = sock_net(sk);
>  	int lo, hi, sk_lo, sk_hi;
> +	bool local_range = false;
>  	u32 sk_range;
>  
> -	inet_get_local_port_range(net, &lo, &hi);
> +	inet_get_local_port_range(sock_net(sk), &lo, &hi);
>  
> -	sk_range = READ_ONCE(inet->local_port_range);
> +	sk_range = READ_ONCE(inet_sk(sk)->local_port_range);
>  	if (unlikely(sk_range)) {
>  		sk_lo = sk_range & 0xffff;
>  		sk_hi = sk_range >> 16;
> @@ -135,10 +144,12 @@ void inet_sk_get_local_port_range(const struct sock *sk, int *low, int *high)
>  			lo = sk_lo;
>  		if (lo <= sk_hi && sk_hi <= hi)
>  			hi = sk_hi;
> +		local_range = true;
>  	}
>  
>  	*low = lo;
>  	*high = hi;
> +	return local_range;
>  }
>  EXPORT_SYMBOL(inet_sk_get_local_port_range);
>  
> -- 
> 2.43.0.472.g3155946c3a-goog