Re: [PATCH net-next 1/3] sctp: do reuseport_select_sock in __sctp_rcv_lookup_endpoint

[Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>]

On Sun, Oct 21, 2018 at 12:43:36PM +0800, Xin Long wrote:
> This is a part of sk_reuseport support for sctp, and it selects a
> sock by the hashkey of lport, paddr and dport by default. It will
> work until sk_reuseport support is added in sctp_get_port_local()
> in the next patch.
> 
> Signed-off-by: Xin Long <lucien.xin@gmail.com>
> ---
>  net/sctp/input.c | 69 +++++++++++++++++++++++++++++++++-----------------------
>  1 file changed, 41 insertions(+), 28 deletions(-)
> 
> diff --git a/net/sctp/input.c b/net/sctp/input.c
> index 5c36a99..60ede89 100644
> --- a/net/sctp/input.c
> +++ b/net/sctp/input.c
> @@ -57,6 +57,7 @@
>  #include <net/sctp/checksum.h>
>  #include <net/net_namespace.h>
>  #include <linux/rhashtable.h>
> +#include <net/sock_reuseport.h>
>  
>  /* Forward declarations for internal helpers. */
>  static int sctp_rcv_ootb(struct sk_buff *);
> @@ -65,8 +66,10 @@ static struct sctp_association *__sctp_rcv_lookup(struct net *net,
>  				      const union sctp_addr *paddr,
>  				      const union sctp_addr *laddr,
>  				      struct sctp_transport **transportp);
> -static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net,
> -						const union sctp_addr *laddr);
> +static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(
> +					struct net *net, struct sk_buff *skb,
> +					const union sctp_addr *laddr,
> +					const union sctp_addr *daddr);
>  static struct sctp_association *__sctp_lookup_association(
>  					struct net *net,
>  					const union sctp_addr *local,
> @@ -171,7 +174,7 @@ int sctp_rcv(struct sk_buff *skb)
>  	asoc = __sctp_rcv_lookup(net, skb, &src, &dest, &transport);
>  
>  	if (!asoc)
> -		ep = __sctp_rcv_lookup_endpoint(net, &dest);
> +		ep = __sctp_rcv_lookup_endpoint(net, skb, &dest, &src);
>  
>  	/* Retrieve the common input handling substructure. */
>  	rcvr = asoc ? &asoc->base : &ep->base;
> @@ -770,16 +773,35 @@ void sctp_unhash_endpoint(struct sctp_endpoint *ep)
>  	local_bh_enable();
>  }
>  
> +static inline __u32 sctp_hashfn(const struct net *net, __be16 lport,
> +				const union sctp_addr *paddr, __u32 seed)
> +{
> +	__u32 addr;
> +
> +	if (paddr->sa.sa_family == AF_INET6)
> +		addr = jhash(&paddr->v6.sin6_addr, 16, seed);
> +	else
> +		addr = (__force __u32)paddr->v4.sin_addr.s_addr;
> +
> +	return  jhash_3words(addr, ((__force __u32)paddr->v4.sin_port) << 16 |
> +			     (__force __u32)lport, net_hash_mix(net), seed);
> +}
> +
>  /* Look up an endpoint. */
> -static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net,
> -						const union sctp_addr *laddr)
> +static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(
> +					struct net *net, struct sk_buff *skb,
> +					const union sctp_addr *laddr,
> +					const union sctp_addr *paddr)
>  {
>  	struct sctp_hashbucket *head;
>  	struct sctp_ep_common *epb;
>  	struct sctp_endpoint *ep;
> +	struct sock *sk;
> +	__be32 lport;

This could be a __be16 one.

>  	int hash;
>  
> -	hash = sctp_ep_hashfn(net, ntohs(laddr->v4.sin_port));
> +	lport = laddr->v4.sin_port;
> +	hash = sctp_ep_hashfn(net, ntohs(lport));
>  	head = &sctp_ep_hashtable[hash];
>  	read_lock(&head->lock);
>  	sctp_for_each_hentry(epb, &head->chain) {
> @@ -791,6 +813,15 @@ static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net,
>  	ep = sctp_sk(net->sctp.ctl_sock)->ep;
>  
>  hit:
> +	sk = ep->base.sk;
> +	if (sk->sk_reuseport) {
> +		__u32 phash = sctp_hashfn(net, lport, paddr, 0);
> +
> +		sk = reuseport_select_sock(sk, phash, skb,
> +					   sizeof(struct sctphdr));
> +		if (sk)
> +			ep = sctp_sk(sk)->ep;
> +	}
>  	sctp_endpoint_hold(ep);
>  	read_unlock(&head->lock);
>  	return ep;
> @@ -829,35 +860,17 @@ static inline int sctp_hash_cmp(struct rhashtable_compare_arg *arg,
>  static inline __u32 sctp_hash_obj(const void *data, u32 len, u32 seed)
>  {
>  	const struct sctp_transport *t = data;
> -	const union sctp_addr *paddr = &t->ipaddr;
> -	const struct net *net = sock_net(t->asoc->base.sk);
> -	__be16 lport = htons(t->asoc->base.bind_addr.port);
> -	__u32 addr;
> -
> -	if (paddr->sa.sa_family == AF_INET6)
> -		addr = jhash(&paddr->v6.sin6_addr, 16, seed);
> -	else
> -		addr = (__force __u32)paddr->v4.sin_addr.s_addr;
>  
> -	return  jhash_3words(addr, ((__force __u32)paddr->v4.sin_port) << 16 |
> -			     (__force __u32)lport, net_hash_mix(net), seed);
> +	return sctp_hashfn(sock_net(t->asoc->base.sk),
> +			   htons(t->asoc->base.bind_addr.port),
> +			   &t->ipaddr, seed);
>  }
>  
>  static inline __u32 sctp_hash_key(const void *data, u32 len, u32 seed)
>  {
>  	const struct sctp_hash_cmp_arg *x = data;
> -	const union sctp_addr *paddr = x->paddr;
> -	const struct net *net = x->net;
> -	__be16 lport = x->lport;
> -	__u32 addr;
> -
> -	if (paddr->sa.sa_family == AF_INET6)
> -		addr = jhash(&paddr->v6.sin6_addr, 16, seed);
> -	else
> -		addr = (__force __u32)paddr->v4.sin_addr.s_addr;
>  
> -	return  jhash_3words(addr, ((__force __u32)paddr->v4.sin_port) << 16 |
> -			     (__force __u32)lport, net_hash_mix(net), seed);
> +	return sctp_hashfn(x->net, x->lport, x->paddr, seed);
>  }
>  
>  static const struct rhashtable_params sctp_hash_params = {
> -- 
> 2.1.0
>