Re: [PATCH v2 02/22] inany: Helper to test for various address types

[Stefano Brivio <sbrivio@redhat.com>]

On Tue,  6 Feb 2024 12:17:14 +1100
David Gibson <david@gibson.dropbear.id.au> wrote:

> Add helpers to determine if an inany is loopback, unspecified or multicast,
> regardless of whether it's a "true" IPv6 address or an IPv4 address
> represented as v4-mapped.
> Sometimes we need to know if an inany is a loopback address, unspecified or
> some other particular kind of address, but we don't really care if it is
> IPv4.
> 
> Use the loopback helper to simplify tcp_splice_conn_from_sock() slightly.
> 
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> ---
>  inany.h      | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  tcp_splice.c | 15 +++------------
>  2 files changed, 53 insertions(+), 12 deletions(-)
> 
> diff --git a/inany.h b/inany.h
> index fe652ff7..2058f145 100644
> --- a/inany.h
> +++ b/inany.h
> @@ -55,6 +55,56 @@ static inline bool inany_equals(const union inany_addr *a,
>  	return IN6_ARE_ADDR_EQUAL(&a->a6, &b->a6);
>  }
>  
> +/** inany_is_loopback - Check if address is loopback

Nit: inany_is_loopback() (and four occurrences below).

> + * @a:		IPv[46] address
> + *
> + * Return: true if @a is either ::1 or in 127.0.0.1/8
> + */
> +static inline bool inany_is_loopback(const union inany_addr *a)
> +{
> +	const struct in_addr *v4 = inany_v4(a);
> +
> +	return IN6_IS_ADDR_LOOPBACK(&a->a6) || (v4 && IN4_IS_ADDR_LOOPBACK(v4));
> +}
> +
> +/** inany_is_unspecified - Check if address is unspecified
> + * @a:		IPv[46] address
> + *
> + * Return: true if @a is either :: or 0.0.0.0
> + */
> +static inline bool inany_is_unspecified(const union inany_addr *a)
> +{
> +	const struct in_addr *v4 = inany_v4(a);
> +
> +	return IN6_IS_ADDR_UNSPECIFIED(&a->a6) ||
> +		(v4 && IN4_IS_ADDR_UNSPECIFIED(v4));
> +}
> +
> +/** inany_is_multicast - Check if address is multicast or broadcast
> + * @a:		IPv[46] address
> + *
> + * Return: true if @a is IPv6 multicast or IPv4 multicast or broadcast
> + */
> +static inline bool inany_is_multicast(const union inany_addr *a)
> +{
> +	const struct in_addr *v4 = inany_v4(a);
> +
> +	return IN6_IS_ADDR_MULTICAST(&a->a6) ||
> +		(v4 && (IN4_IS_ADDR_MULTICAST(v4) ||
> +			IN4_IS_ADDR_BROADCAST(v4)));
> +}
> +
> +/** inany_is_unicast - Check if address is specified and unicast
> + * @a:		IPv[46] address
> + *
> + * Return: true if @a is specified and a unicast address
> + */
> +/* cppcheck-suppress unusedFunction */
> +static inline bool inany_is_unicast(const union inany_addr *a)
> +{
> +	return !inany_is_unspecified(a) && !inany_is_multicast(a);
> +}
> +
>  /** inany_from_af - Set IPv[46] address from IPv4 or IPv6 address
>   * @aa:		Pointer to store IPv[46] address
>   * @af:		Address family of @addr
> diff --git a/tcp_splice.c b/tcp_splice.c
> index cc9745e8..4ecc178b 100644
> --- a/tcp_splice.c
> +++ b/tcp_splice.c
> @@ -440,29 +440,20 @@ bool tcp_splice_conn_from_sock(const struct ctx *c,
>  			       struct tcp_splice_conn *conn, int s,
>  			       const struct sockaddr *sa)
>  {
> -	const struct in_addr *a4;
>  	union inany_addr aany;
>  	in_port_t port;
>  
>  	ASSERT(c->mode == MODE_PASTA);
>  
>  	inany_from_sockaddr(&aany, &port, sa);
> -	a4 = inany_v4(&aany);
> -
> -	if (a4) {
> -		if (!IN4_IS_ADDR_LOOPBACK(a4))
> -			return false;
> -		conn->flags = 0;
> -	} else {
> -		if (!IN6_IS_ADDR_LOOPBACK(&aany.a6))
> -			return false;
> -		conn->flags = SPLICE_V6;
> -	}
> +	if (!inany_is_loopback(&aany))
> +		return false;
>  
>  	if (setsockopt(s, SOL_TCP, TCP_QUICKACK, &((int){ 1 }), sizeof(int)))
>  		flow_trace(conn, "failed to set TCP_QUICKACK on %i", s);
>  
>  	conn->f.type = FLOW_TCP_SPLICE;
> +	conn->flags = inany_v4(&aany) ? 0 : SPLICE_V6;
>  	conn->s[0] = s;
>  
>  	if (tcp_splice_new(c, conn, ref.port, ref.pif))