Re: [PATCH v6 net-next 4/4] ipv6/udp: Add 4-tuple hash for connected socket

[Philo Lu]

On 2024/10/31 20:45, Philo Lu wrote:
> Implement ipv6 udp hash4 like that in ipv4. The major difference is that
> the hash value should be calculated with udp6_ehashfn(). Besides,
> ipv4-mapped ipv6 address is handled before hash() and rehash().
>
> Core procedures of hash/unhash/rehash are same as ipv4, and udpv4 and
> udpv6 share the same udptable, so some functions in ipv4 hash4 can also
> be shared.
>
> Signed-off-by: Philo Lu <lulie@xxxxxxxxxxxxxxxxx>
> Signed-off-by: Cambda Zhu <cambda@xxxxxxxxxxxxxxxxx>
> Signed-off-by: Fred Chen <fred.cc@xxxxxxxxxxxxxxx>
> Signed-off-by: Yubing Qiu <yubing.qiuyubing@xxxxxxxxxxxxxxx>
> ---
>   net/ipv6/udp.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++++--
>   1 file changed, 94 insertions(+), 2 deletions(-)
>
> diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
> index 1ea99d704e31..64f13f258fca 100644
> --- a/net/ipv6/udp.c
> +++ b/net/ipv6/udp.c
> @@ -110,8 +110,17 @@ void udp_v6_rehash(struct sock *sk)
>   	u16 new_hash = ipv6_portaddr_hash(sock_net(sk),
>   					  &sk->sk_v6_rcv_saddr,
>   					  inet_sk(sk)->inet_num);
> +	u16 new_hash4;
>   
> -	udp_lib_rehash(sk, new_hash, 0); /* 4-tuple hash not implemented */
> +	if (ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr)) {
> +		new_hash4 = udp_ehashfn(sock_net(sk), sk->sk_rcv_saddr, sk->sk_num,
> +					sk->sk_daddr, sk->sk_dport);

Just found udp_ehashfn() used here results in an build error of 
undefined function.

I think the `ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr)` branch can be 
moved into udp_lib_rehash() to fix the issue. So in the worst case, we 
need to calculate the newhash4 twice in ipv6 hash4 rehash, one in 
udp_v6_rehash() and the other in udp_lib_rehash().

> +	} else {
> +		new_hash4 = udp6_ehashfn(sock_net(sk), &sk->sk_v6_rcv_saddr, sk->sk_num,
> +					 &sk->sk_v6_daddr, sk->sk_dport);
> +	}
> +
> +	udp_lib_rehash(sk, new_hash, new_hash4);
>   }
>   

--
Philo