Merge branch 'listen_refactor_part_13'

Eric Dumazet says:

====================
inet: tcp listener refactoring, part 13

inet_hash functions are in a bad state : Too much IPv6/IPv4 copy/pasting.

Lets refactor a bit.

Idea is that we do not want to have an equivalent of inet_csk(sk)->icsk_af_ops
for request socks in order to be able to use the right variant.

In this patch series, I started to let IPv6/IPv4 converge to common helpers.

Idea is to use ipv6_addr_set_v4mapped() even for AF_INET sockets, so that
we can test
       if (sk->sk_family == AF_INET6 &&
           !ipv6_addr_v4mapped(&sk->sk_v6_daddr))
to tell if we deal with an IPv6 socket, or IPv4 one, at least in slow paths.

Ideally, we could save 8 bytes per struct sock_common, if we
alias skc_daddr & skc_rcv_saddr to skc_v6_daddr[3]/skc_v6_rcv_saddr[3].
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/udp.h

@@ -34,7 +34,7 @@ static inline struct udphdr *inner_udp_hdr(const struct sk_buff *skb)
 
 #define UDP_HTABLE_SIZE_MIN		(CONFIG_BASE_SMALL ? 128 : 256)
 
-static inline int udp_hashfn(struct net *net, unsigned num, unsigned mask)
+static inline u32 udp_hashfn(const struct net *net, u32 num, u32 mask)
 {
 	return (num + net_hash_mix(net)) & mask;
 }

include/net/inet6_hashtables.h

@@ -38,8 +38,6 @@ static inline unsigned int __inet6_ehashfn(const u32 lhash,
 	return jhash_3words(lhash, fhash, ports, initval);
 }
 
-int __inet6_hash(struct sock *sk, struct inet_timewait_sock *twp);
-
 /*
  * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
  * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM

include/net/inet_hashtables.h

@@ -221,8 +221,8 @@ inet_bind_bucket_create(struct kmem_cache *cachep, struct net *net,
 void inet_bind_bucket_destroy(struct kmem_cache *cachep,
 			      struct inet_bind_bucket *tb);
 
-static inline int inet_bhashfn(struct net *net, const __u16 lport,
-			       const int bhash_size)
+static inline u32 inet_bhashfn(const struct net *net, const __u16 lport,
+			       const u32 bhash_size)
 {
 	return (lport + net_hash_mix(net)) & (bhash_size - 1);
 }
@@ -231,7 +231,7 @@ void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
 		    const unsigned short snum);
 
 /* These can have wildcards, don't try too hard. */
-static inline int inet_lhashfn(struct net *net, const unsigned short num)
+static inline u32 inet_lhashfn(const struct net *net, const unsigned short num)
 {
 	return (num + net_hash_mix(net)) & (INET_LHTABLE_SIZE - 1);
 }
@@ -249,6 +249,7 @@ void inet_put_port(struct sock *sk);
 void inet_hashinfo_init(struct inet_hashinfo *h);
 
 int __inet_hash_nolisten(struct sock *sk, struct inet_timewait_sock *tw);
+int __inet_hash(struct sock *sk, struct inet_timewait_sock *tw);
 void inet_hash(struct sock *sk);
 void inet_unhash(struct sock *sk);
 
@@ -383,13 +384,32 @@ static inline struct sock *__inet_lookup_skb(struct inet_hashinfo *hashinfo,
 				     iph->daddr, dport, inet_iif(skb));
 }
 
+u32 sk_ehashfn(const struct sock *sk);
+u32 inet6_ehashfn(const struct net *net,
+		  const struct in6_addr *laddr, const u16 lport,
+		  const struct in6_addr *faddr, const __be16 fport);
+
+static inline void sk_daddr_set(struct sock *sk, __be32 addr)
+{
+	sk->sk_daddr = addr; /* alias of inet_daddr */
+#if IS_ENABLED(CONFIG_IPV6)
+	ipv6_addr_set_v4mapped(addr, &sk->sk_v6_daddr);
+#endif
+}
+
+static inline void sk_rcv_saddr_set(struct sock *sk, __be32 addr)
+{
+	sk->sk_rcv_saddr = addr; /* alias of inet_rcv_saddr */
+#if IS_ENABLED(CONFIG_IPV6)
+	ipv6_addr_set_v4mapped(addr, &sk->sk_v6_rcv_saddr);
+#endif
+}
+
 int __inet_hash_connect(struct inet_timewait_death_row *death_row,
 			struct sock *sk, u32 port_offset,
 			int (*check_established)(struct inet_timewait_death_row *,
 						 struct sock *, __u16,
-						 struct inet_timewait_sock **),
-			int (*hash)(struct sock *sk,
-				    struct inet_timewait_sock *twp));
+						 struct inet_timewait_sock **));
 
 int inet_hash_connect(struct inet_timewait_death_row *death_row,
 		      struct sock *sk);

include/net/netns/hash.h

@@ -5,15 +5,15 @@
 
 struct net;
 
-static inline unsigned int net_hash_mix(struct net *net)
+static inline u32 net_hash_mix(const struct net *net)
 {
 #ifdef CONFIG_NET_NS
 	/*
 	 * shift this right to eliminate bits, that are
 	 * always zeroed
 	 */
 
-	return (unsigned)(((unsigned long)net) >> L1_CACHE_SHIFT);
+	return (u32)(((unsigned long)net) >> L1_CACHE_SHIFT);
 #else
 	return 0;
 #endif

include/net/request_sock.h

@@ -91,6 +91,11 @@ static inline struct request_sock *inet_reqsk(struct sock *sk)
 	return (struct request_sock *)sk;
 }
 
+static inline struct sock *req_to_sk(struct request_sock *req)
+{
+	return (struct sock *)req;
+}
+
 static inline void reqsk_free(struct request_sock *req)
 {
 	/* temporary debugging */

net/dccp/ipv4.c

@@ -89,10 +89,9 @@ int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 
 	if (inet->inet_saddr == 0)
 		inet->inet_saddr = fl4->saddr;
-	inet->inet_rcv_saddr = inet->inet_saddr;
-
+	sk_rcv_saddr_set(sk, inet->inet_saddr);
 	inet->inet_dport = usin->sin_port;
-	inet->inet_daddr = daddr;
+	sk_daddr_set(sk, daddr);
 
 	inet_csk(sk)->icsk_ext_hdr_len = 0;
 	if (inet_opt)
@@ -408,8 +407,8 @@ struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
 
 	newinet		   = inet_sk(newsk);
 	ireq		   = inet_rsk(req);
-	newinet->inet_daddr	= ireq->ir_rmt_addr;
-	newinet->inet_rcv_saddr = ireq->ir_loc_addr;
+	sk_daddr_set(newsk, ireq->ir_rmt_addr);
+	sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
 	newinet->inet_saddr	= ireq->ir_loc_addr;
 	newinet->inet_opt	= ireq->opt;
 	ireq->opt	   = NULL;
@@ -639,8 +638,8 @@ int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 		goto drop_and_free;
 
 	ireq = inet_rsk(req);
-	ireq->ir_loc_addr = ip_hdr(skb)->daddr;
-	ireq->ir_rmt_addr = ip_hdr(skb)->saddr;
+	sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
+	sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
 	ireq->ireq_family = AF_INET;
 	ireq->ir_iif = sk->sk_bound_dev_if;
 

net/dccp/ipv6.c

@@ -40,19 +40,6 @@
 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped;
 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops;
 
-static void dccp_v6_hash(struct sock *sk)
-{
-	if (sk->sk_state != DCCP_CLOSED) {
-		if (inet_csk(sk)->icsk_af_ops == &dccp_ipv6_mapped) {
-			inet_hash(sk);
-			return;
-		}
-		local_bh_disable();
-		__inet6_hash(sk, NULL);
-		local_bh_enable();
-	}
-}
-
 /* add pseudo-header to DCCP checksum stored in skb->csum */
 static inline __sum16 dccp_v6_csum_finish(struct sk_buff *skb,
 				      const struct in6_addr *saddr,
@@ -470,11 +457,7 @@ static struct sock *dccp_v6_request_recv_sock(struct sock *sk,
 
 		memcpy(newnp, np, sizeof(struct ipv6_pinfo));
 
-		ipv6_addr_set_v4mapped(newinet->inet_daddr, &newsk->sk_v6_daddr);
-
-		ipv6_addr_set_v4mapped(newinet->inet_saddr, &newnp->saddr);
-
-		newsk->sk_v6_rcv_saddr = newnp->saddr;
+		newnp->saddr = newsk->sk_v6_rcv_saddr;
 
 		inet_csk(newsk)->icsk_af_ops = &dccp_ipv6_mapped;
 		newsk->sk_backlog_rcv = dccp_v4_do_rcv;
@@ -592,7 +575,7 @@ static struct sock *dccp_v6_request_recv_sock(struct sock *sk,
 		dccp_done(newsk);
 		goto out;
 	}
-	__inet6_hash(newsk, NULL);
+	__inet_hash(newsk, NULL);
 
 	return newsk;
 
@@ -917,9 +900,7 @@ static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 			sk->sk_backlog_rcv = dccp_v6_do_rcv;
 			goto failure;
 		}
-		ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);
-		ipv6_addr_set_v4mapped(inet->inet_rcv_saddr, &sk->sk_v6_rcv_saddr);
-
+		np->saddr = sk->sk_v6_rcv_saddr;
 		return err;
 	}
 
@@ -1062,7 +1043,7 @@ static struct proto dccp_v6_prot = {
 	.sendmsg	   = dccp_sendmsg,
 	.recvmsg	   = dccp_recvmsg,
 	.backlog_rcv	   = dccp_v6_do_rcv,
-	.hash		   = dccp_v6_hash,
+	.hash		   = inet_hash,
 	.unhash		   = inet_unhash,
 	.accept		   = inet_csk_accept,
 	.get_port	   = inet_csk_get_port,

net/ipv4/devinet.c

@@ -107,7 +107,7 @@ static const struct nla_policy ifa_ipv4_policy[IFA_MAX+1] = {
 
 static struct hlist_head inet_addr_lst[IN4_ADDR_HSIZE];
 
-static u32 inet_addr_hash(struct net *net, __be32 addr)
+static u32 inet_addr_hash(const struct net *net, __be32 addr)
 {
 	u32 val = (__force u32) addr ^ net_hash_mix(net);
 

net/ipv4/inet_diag.c

@@ -742,14 +742,14 @@ static int inet_diag_dump_reqs(struct sk_buff *skb, struct sock *sk,
 
 			if (bc) {
 				/* Note: entry.sport and entry.userlocks are already set */
-				entry_fill_addrs(&entry, (struct sock *)req);
+				entry_fill_addrs(&entry, req_to_sk(req));
 				entry.dport = ntohs(ireq->ir_rmt_port);
 
 				if (!inet_diag_bc_run(bc, &entry))
 					continue;
 			}
 
-			err = inet_req_diag_fill((struct sock *)req, skb,
+			err = inet_req_diag_fill(req_to_sk(req), skb,
 						 NETLINK_CB(cb->skb).portid,
 						 cb->nlh->nlmsg_seq,
 						 NLM_F_MULTI, cb->nlh);

net/ipv4/inet_hashtables.c

@@ -24,9 +24,9 @@
 #include <net/secure_seq.h>
 #include <net/ip.h>
 
-static unsigned int inet_ehashfn(struct net *net, const __be32 laddr,
-				 const __u16 lport, const __be32 faddr,
-				 const __be16 fport)
+static u32 inet_ehashfn(const struct net *net, const __be32 laddr,
+			const __u16 lport, const __be32 faddr,
+			const __be16 fport)
 {
 	static u32 inet_ehash_secret __read_mostly;
 
@@ -36,17 +36,21 @@ static unsigned int inet_ehashfn(struct net *net, const __be32 laddr,
 			      inet_ehash_secret + net_hash_mix(net));
 }
 
-
-static unsigned int inet_sk_ehashfn(const struct sock *sk)
+/* This function handles inet_sock, but also timewait and request sockets
+ * for IPv4/IPv6.
+ */
+u32 sk_ehashfn(const struct sock *sk)
 {
-	const struct inet_sock *inet = inet_sk(sk);
-	const __be32 laddr = inet->inet_rcv_saddr;
-	const __u16 lport = inet->inet_num;
-	const __be32 faddr = inet->inet_daddr;
-	const __be16 fport = inet->inet_dport;
-	struct net *net = sock_net(sk);
-
-	return inet_ehashfn(net, laddr, lport, faddr, fport);
+#if IS_ENABLED(CONFIG_IPV6)
+	if (sk->sk_family == AF_INET6 &&
+	    !ipv6_addr_v4mapped(&sk->sk_v6_daddr))
+		return inet6_ehashfn(sock_net(sk),
+				     &sk->sk_v6_rcv_saddr, sk->sk_num,
+				     &sk->sk_v6_daddr, sk->sk_dport);
+#endif
+	return inet_ehashfn(sock_net(sk),
+			    sk->sk_rcv_saddr, sk->sk_num,
+			    sk->sk_daddr, sk->sk_dport);
 }
 
 /*
@@ -407,13 +411,13 @@ int __inet_hash_nolisten(struct sock *sk, struct inet_timewait_sock *tw)
 {
 	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 	struct hlist_nulls_head *list;
-	spinlock_t *lock;
 	struct inet_ehash_bucket *head;
+	spinlock_t *lock;
 	int twrefcnt = 0;
 
 	WARN_ON(!sk_unhashed(sk));
 
-	sk->sk_hash = inet_sk_ehashfn(sk);
+	sk->sk_hash = sk_ehashfn(sk);
 	head = inet_ehash_bucket(hashinfo, sk->sk_hash);
 	list = &head->chain;
 	lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
@@ -430,15 +434,13 @@ int __inet_hash_nolisten(struct sock *sk, struct inet_timewait_sock *tw)
 }
 EXPORT_SYMBOL_GPL(__inet_hash_nolisten);
 
-static void __inet_hash(struct sock *sk)
+int __inet_hash(struct sock *sk, struct inet_timewait_sock *tw)
 {
 	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 	struct inet_listen_hashbucket *ilb;
 
-	if (sk->sk_state != TCP_LISTEN) {
-		__inet_hash_nolisten(sk, NULL);
-		return;
-	}
+	if (sk->sk_state != TCP_LISTEN)
+		return __inet_hash_nolisten(sk, tw);
 
 	WARN_ON(!sk_unhashed(sk));
 	ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
@@ -447,13 +449,15 @@ static void __inet_hash(struct sock *sk)
 	__sk_nulls_add_node_rcu(sk, &ilb->head);
 	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 	spin_unlock(&ilb->lock);
+	return 0;
 }
+EXPORT_SYMBOL(__inet_hash);
 
 void inet_hash(struct sock *sk)
 {
 	if (sk->sk_state != TCP_CLOSE) {
 		local_bh_disable();
-		__inet_hash(sk);
+		__inet_hash(sk, NULL);
 		local_bh_enable();
 	}
 }
@@ -484,8 +488,7 @@ EXPORT_SYMBOL_GPL(inet_unhash);
 int __inet_hash_connect(struct inet_timewait_death_row *death_row,
 		struct sock *sk, u32 port_offset,
 		int (*check_established)(struct inet_timewait_death_row *,
-			struct sock *, __u16, struct inet_timewait_sock **),
-		int (*hash)(struct sock *sk, struct inet_timewait_sock *twp))
+			struct sock *, __u16, struct inet_timewait_sock **))
 {
 	struct inet_hashinfo *hinfo = death_row->hashinfo;
 	const unsigned short snum = inet_sk(sk)->inet_num;
@@ -555,7 +558,7 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row,
 		inet_bind_hash(sk, tb, port);
 		if (sk_unhashed(sk)) {
 			inet_sk(sk)->inet_sport = htons(port);
-			twrefcnt += hash(sk, tw);
+			twrefcnt += __inet_hash_nolisten(sk, tw);
 		}
 		if (tw)
 			twrefcnt += inet_twsk_bind_unhash(tw, hinfo);
@@ -577,7 +580,7 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row,
 	tb  = inet_csk(sk)->icsk_bind_hash;
 	spin_lock_bh(&head->lock);
 	if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
-		hash(sk, NULL);
+		__inet_hash_nolisten(sk, NULL);
 		spin_unlock_bh(&head->lock);
 		return 0;
 	} else {
@@ -597,7 +600,7 @@ int inet_hash_connect(struct inet_timewait_death_row *death_row,
 		      struct sock *sk)
 {
 	return __inet_hash_connect(death_row, sk, inet_sk_port_offset(sk),
-			__inet_check_established, __inet_hash_nolisten);
+				   __inet_check_established);
 }
 EXPORT_SYMBOL_GPL(inet_hash_connect);
 

net/ipv4/ping.c

@@ -64,11 +64,11 @@ EXPORT_SYMBOL_GPL(pingv6_ops);
 
 static u16 ping_port_rover;
 
-static inline int ping_hashfn(struct net *net, unsigned int num, unsigned int mask)
+static inline u32 ping_hashfn(const struct net *net, u32 num, u32 mask)
 {
-	int res = (num + net_hash_mix(net)) & mask;
+	u32 res = (num + net_hash_mix(net)) & mask;
 
-	pr_debug("hash(%d) = %d\n", num, res);
+	pr_debug("hash(%u) = %u\n", num, res);
 	return res;
 }
 EXPORT_SYMBOL_GPL(ping_hash);

net/ipv4/syncookies.c

@@ -337,8 +337,8 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
 	req->mss		= mss;
 	ireq->ir_num		= ntohs(th->dest);
 	ireq->ir_rmt_port	= th->source;
-	ireq->ir_loc_addr	= ip_hdr(skb)->daddr;
-	ireq->ir_rmt_addr	= ip_hdr(skb)->saddr;
+	sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
+	sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
 	ireq->ir_mark		= inet_request_mark(sk, skb);
 	ireq->snd_wscale	= tcp_opt.snd_wscale;
 	ireq->sack_ok		= tcp_opt.sack_ok;