1 files changed, 338 insertions, 0 deletions
diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c
new file mode 100644
index 000000000..b64b49012
--- /dev/null
+++ b/net/ipv6/inet6_hashtables.c
@@ -0,0 +1,338 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * INET		An implementation of the TCP/IP protocol suite for the LINUX
+ *		operating system.  INET is implemented using the BSD Socket
+ *		interface as the means of communication with the user level.
+ *
+ *		Generic INET6 transport hashtables
+ *
+ * Authors:	Lotsa people, from code originally in tcp, generalised here
+ *		by Arnaldo Carvalho de Melo <acme@mandriva.com>
+ */
+
+#include <linux/module.h>
+#include <linux/random.h>
+
+#include <net/addrconf.h>
+#include <net/inet_connection_sock.h>
+#include <net/inet_hashtables.h>
+#include <net/inet6_hashtables.h>
+#include <net/secure_seq.h>
+#include <net/ip.h>
+#include <net/sock_reuseport.h>
+
+u32 inet6_ehashfn(const struct net *net,
+		  const struct in6_addr *laddr, const u16 lport,
+		  const struct in6_addr *faddr, const __be16 fport)
+{
+	static u32 inet6_ehash_secret __read_mostly;
+	static u32 ipv6_hash_secret __read_mostly;
+
+	u32 lhash, fhash;
+
+	net_get_random_once(&inet6_ehash_secret, sizeof(inet6_ehash_secret));
+	net_get_random_once(&ipv6_hash_secret, sizeof(ipv6_hash_secret));
+
+	lhash = (__force u32)laddr->s6_addr32[3];
+	fhash = __ipv6_addr_jhash(faddr, ipv6_hash_secret);
+
+	return __inet6_ehashfn(lhash, lport, fhash, fport,
+			       inet6_ehash_secret + net_hash_mix(net));
+}
+
+/*
+ * 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
+ *
+ * The sockhash lock must be held as a reader here.
+ */
+struct sock *__inet6_lookup_established(struct net *net,
+					struct inet_hashinfo *hashinfo,
+					   const struct in6_addr *saddr,
+					   const __be16 sport,
+					   const struct in6_addr *daddr,
+					   const u16 hnum,
+					   const int dif, const int sdif)
+{
+	struct sock *sk;
+	const struct hlist_nulls_node *node;
+	const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
+	/* Optimize here for direct hit, only listening connections can
+	 * have wildcards anyways.
+	 */
+	unsigned int hash = inet6_ehashfn(net, daddr, hnum, saddr, sport);
+	unsigned int slot = hash & hashinfo->ehash_mask;
+	struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
+
+
+begin:
+	sk_nulls_for_each_rcu(sk, node, &head->chain) {
+		if (sk->sk_hash != hash)
+			continue;
+		if (!inet6_match(net, sk, saddr, daddr, ports, dif, sdif))
+			continue;
+		if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))
+			goto out;
+
+		if (unlikely(!inet6_match(net, sk, saddr, daddr, ports, dif, sdif))) {
+			sock_gen_put(sk);
+			goto begin;
+		}
+		goto found;
+	}
+	if (get_nulls_value(node) != slot)
+		goto begin;
+out:
+	sk = NULL;
+found:
+	return sk;
+}
+EXPORT_SYMBOL(__inet6_lookup_established);
+
+static inline int compute_score(struct sock *sk, struct net *net,
+				const unsigned short hnum,
+				const struct in6_addr *daddr,
+				const int dif, const int sdif)
+{
+	int score = -1;
+
+	if (net_eq(sock_net(sk), net) && inet_sk(sk)->inet_num == hnum &&
+	    sk->sk_family == PF_INET6) {
+		if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr))
+			return -1;
+
+		if (!inet_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif))
+			return -1;
+
+		score =  sk->sk_bound_dev_if ? 2 : 1;
+		if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id())
+			score++;
+	}
+	return score;
+}
+
+static inline struct sock *lookup_reuseport(struct net *net, struct sock *sk,
+					    struct sk_buff *skb, int doff,
+					    const struct in6_addr *saddr,
+					    __be16 sport,
+					    const struct in6_addr *daddr,
+					    unsigned short hnum)
+{
+	struct sock *reuse_sk = NULL;
+	u32 phash;
+
+	if (sk->sk_reuseport) {
+		phash = inet6_ehashfn(net, daddr, hnum, saddr, sport);
+		reuse_sk = reuseport_select_sock(sk, phash, skb, doff);
+	}
+	return reuse_sk;
+}
+
+/* called with rcu_read_lock() */
+static struct sock *inet6_lhash2_lookup(struct net *net,
+		struct inet_listen_hashbucket *ilb2,
+		struct sk_buff *skb, int doff,
+		const struct in6_addr *saddr,
+		const __be16 sport, const struct in6_addr *daddr,
+		const unsigned short hnum, const int dif, const int sdif)
+{
+	struct sock *sk, *result = NULL;
+	struct hlist_nulls_node *node;
+	int score, hiscore = 0;
+
+	sk_nulls_for_each_rcu(sk, node, &ilb2->nulls_head) {
+		score = compute_score(sk, net, hnum, daddr, dif, sdif);
+		if (score > hiscore) {
+			result = lookup_reuseport(net, sk, skb, doff,
+						  saddr, sport, daddr, hnum);
+			if (result)
+				return result;
+
+			result = sk;
+			hiscore = score;
+		}
+	}
+
+	return result;
+}
+
+static inline struct sock *inet6_lookup_run_bpf(struct net *net,
+						struct inet_hashinfo *hashinfo,
+						struct sk_buff *skb, int doff,
+						const struct in6_addr *saddr,
+						const __be16 sport,
+						const struct in6_addr *daddr,
+						const u16 hnum, const int dif)
+{
+	struct sock *sk, *reuse_sk;
+	bool no_reuseport;
+
+	if (hashinfo != net->ipv4.tcp_death_row.hashinfo)
+		return NULL; /* only TCP is supported */
+
+	no_reuseport = bpf_sk_lookup_run_v6(net, IPPROTO_TCP, saddr, sport,
+					    daddr, hnum, dif, &sk);
+	if (no_reuseport || IS_ERR_OR_NULL(sk))
+		return sk;
+
+	reuse_sk = lookup_reuseport(net, sk, skb, doff, saddr, sport, daddr, hnum);
+	if (reuse_sk)
+		sk = reuse_sk;
+	return sk;
+}
+
+struct sock *inet6_lookup_listener(struct net *net,
+		struct inet_hashinfo *hashinfo,
+		struct sk_buff *skb, int doff,
+		const struct in6_addr *saddr,
+		const __be16 sport, const struct in6_addr *daddr,
+		const unsigned short hnum, const int dif, const int sdif)
+{
+	struct inet_listen_hashbucket *ilb2;
+	struct sock *result = NULL;
+	unsigned int hash2;
+
+	/* Lookup redirect from BPF */
+	if (static_branch_unlikely(&bpf_sk_lookup_enabled)) {
+		result = inet6_lookup_run_bpf(net, hashinfo, skb, doff,
+					      saddr, sport, daddr, hnum, dif);
+		if (result)
+			goto done;
+	}
+
+	hash2 = ipv6_portaddr_hash(net, daddr, hnum);
+	ilb2 = inet_lhash2_bucket(hashinfo, hash2);
+
+	result = inet6_lhash2_lookup(net, ilb2, skb, doff,
+				     saddr, sport, daddr, hnum,
+				     dif, sdif);
+	if (result)
+		goto done;
+
+	/* Lookup lhash2 with in6addr_any */
+	hash2 = ipv6_portaddr_hash(net, &in6addr_any, hnum);
+	ilb2 = inet_lhash2_bucket(hashinfo, hash2);
+
+	result = inet6_lhash2_lookup(net, ilb2, skb, doff,
+				     saddr, sport, &in6addr_any, hnum,
+				     dif, sdif);
+done:
+	if (IS_ERR(result))
+		return NULL;
+	return result;
+}
+EXPORT_SYMBOL_GPL(inet6_lookup_listener);
+
+struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo,
+			  struct sk_buff *skb, int doff,
+			  const struct in6_addr *saddr, const __be16 sport,
+			  const struct in6_addr *daddr, const __be16 dport,
+			  const int dif)
+{
+	struct sock *sk;
+	bool refcounted;
+
+	sk = __inet6_lookup(net, hashinfo, skb, doff, saddr, sport, daddr,
+			    ntohs(dport), dif, 0, &refcounted);
+	if (sk && !refcounted && !refcount_inc_not_zero(&sk->sk_refcnt))
+		sk = NULL;
+	return sk;
+}
+EXPORT_SYMBOL_GPL(inet6_lookup);
+
+static int __inet6_check_established(struct inet_timewait_death_row *death_row,
+				     struct sock *sk, const __u16 lport,
+				     struct inet_timewait_sock **twp)
+{
+	struct inet_hashinfo *hinfo = death_row->hashinfo;
+	struct inet_sock *inet = inet_sk(sk);
+	const struct in6_addr *daddr = &sk->sk_v6_rcv_saddr;
+	const struct in6_addr *saddr = &sk->sk_v6_daddr;
+	const int dif = sk->sk_bound_dev_if;
+	struct net *net = sock_net(sk);
+	const int sdif = l3mdev_master_ifindex_by_index(net, dif);
+	const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
+	const unsigned int hash = inet6_ehashfn(net, daddr, lport, saddr,
+						inet->inet_dport);
+	struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
+	spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
+	struct sock *sk2;
+	const struct hlist_nulls_node *node;
+	struct inet_timewait_sock *tw = NULL;
+
+	spin_lock(lock);
+
+	sk_nulls_for_each(sk2, node, &head->chain) {
+		if (sk2->sk_hash != hash)
+			continue;
+
+		if (likely(inet6_match(net, sk2, saddr, daddr, ports,
+				       dif, sdif))) {
+			if (sk2->sk_state == TCP_TIME_WAIT) {
+				tw = inet_twsk(sk2);
+				if (twsk_unique(sk, sk2, twp))
+					break;
+			}
+			goto not_unique;
+		}
+	}
+
+	/* Must record num and sport now. Otherwise we will see
+	 * in hash table socket with a funny identity.
+	 */
+	inet->inet_num = lport;
+	inet->inet_sport = htons(lport);
+	sk->sk_hash = hash;
+	WARN_ON(!sk_unhashed(sk));
+	__sk_nulls_add_node_rcu(sk, &head->chain);
+	if (tw) {
+		sk_nulls_del_node_init_rcu((struct sock *)tw);
+		__NET_INC_STATS(net, LINUX_MIB_TIMEWAITRECYCLED);
+	}
+	spin_unlock(lock);
+	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
+
+	if (twp) {
+		*twp = tw;
+	} else if (tw) {
+		/* Silly. Should hash-dance instead... */
+		inet_twsk_deschedule_put(tw);
+	}
+	return 0;
+
+not_unique:
+	spin_unlock(lock);
+	return -EADDRNOTAVAIL;
+}
+
+static u64 inet6_sk_port_offset(const struct sock *sk)
+{
+	const struct inet_sock *inet = inet_sk(sk);
+
+	return secure_ipv6_port_ephemeral(sk->sk_v6_rcv_saddr.s6_addr32,
+					  sk->sk_v6_daddr.s6_addr32,
+					  inet->inet_dport);
+}
+
+int inet6_hash_connect(struct inet_timewait_death_row *death_row,
+		       struct sock *sk)
+{
+	u64 port_offset = 0;
+
+	if (!inet_sk(sk)->inet_num)
+		port_offset = inet6_sk_port_offset(sk);
+	return __inet_hash_connect(death_row, sk, port_offset,
+				   __inet6_check_established);
+}
+EXPORT_SYMBOL_GPL(inet6_hash_connect);
+
+int inet6_hash(struct sock *sk)
+{
+	int err = 0;
+
+	if (sk->sk_state != TCP_CLOSE)
+		err = __inet_hash(sk, NULL);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(inet6_hash);