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-rw-r--r--include/net/inet_hashtables.h479
1 files changed, 479 insertions, 0 deletions
diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
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--- /dev/null
+++ b/include/net/inet_hashtables.h
@@ -0,0 +1,479 @@
+/* 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.
+ *
+ * Authors: Lotsa people, from code originally in tcp
+ */
+
+#ifndef _INET_HASHTABLES_H
+#define _INET_HASHTABLES_H
+
+
+#include <linux/interrupt.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/socket.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+
+#include <net/inet_connection_sock.h>
+#include <net/inet_sock.h>
+#include <net/ip.h>
+#include <net/sock.h>
+#include <net/route.h>
+#include <net/tcp_states.h>
+#include <net/netns/hash.h>
+
+#include <linux/refcount.h>
+#include <asm/byteorder.h>
+
+/* This is for all connections with a full identity, no wildcards.
+ * The 'e' prefix stands for Establish, but we really put all sockets
+ * but LISTEN ones.
+ */
+struct inet_ehash_bucket {
+ struct hlist_nulls_head chain;
+};
+
+/* There are a few simple rules, which allow for local port reuse by
+ * an application. In essence:
+ *
+ * 1) Sockets bound to different interfaces may share a local port.
+ * Failing that, goto test 2.
+ * 2) If all sockets have sk->sk_reuse set, and none of them are in
+ * TCP_LISTEN state, the port may be shared.
+ * Failing that, goto test 3.
+ * 3) If all sockets are bound to a specific inet_sk(sk)->rcv_saddr local
+ * address, and none of them are the same, the port may be
+ * shared.
+ * Failing this, the port cannot be shared.
+ *
+ * The interesting point, is test #2. This is what an FTP server does
+ * all day. To optimize this case we use a specific flag bit defined
+ * below. As we add sockets to a bind bucket list, we perform a
+ * check of: (newsk->sk_reuse && (newsk->sk_state != TCP_LISTEN))
+ * As long as all sockets added to a bind bucket pass this test,
+ * the flag bit will be set.
+ * The resulting situation is that tcp_v[46]_verify_bind() can just check
+ * for this flag bit, if it is set and the socket trying to bind has
+ * sk->sk_reuse set, we don't even have to walk the owners list at all,
+ * we return that it is ok to bind this socket to the requested local port.
+ *
+ * Sounds like a lot of work, but it is worth it. In a more naive
+ * implementation (ie. current FreeBSD etc.) the entire list of ports
+ * must be walked for each data port opened by an ftp server. Needless
+ * to say, this does not scale at all. With a couple thousand FTP
+ * users logged onto your box, isn't it nice to know that new data
+ * ports are created in O(1) time? I thought so. ;-) -DaveM
+ */
+#define FASTREUSEPORT_ANY 1
+#define FASTREUSEPORT_STRICT 2
+
+struct inet_bind_bucket {
+ possible_net_t ib_net;
+ int l3mdev;
+ unsigned short port;
+ signed char fastreuse;
+ signed char fastreuseport;
+ kuid_t fastuid;
+#if IS_ENABLED(CONFIG_IPV6)
+ struct in6_addr fast_v6_rcv_saddr;
+#endif
+ __be32 fast_rcv_saddr;
+ unsigned short fast_sk_family;
+ bool fast_ipv6_only;
+ struct hlist_node node;
+ struct hlist_head owners;
+};
+
+struct inet_bind2_bucket {
+ possible_net_t ib_net;
+ int l3mdev;
+ unsigned short port;
+#if IS_ENABLED(CONFIG_IPV6)
+ unsigned short family;
+#endif
+ union {
+#if IS_ENABLED(CONFIG_IPV6)
+ struct in6_addr v6_rcv_saddr;
+#endif
+ __be32 rcv_saddr;
+ };
+ /* Node in the bhash2 inet_bind_hashbucket chain */
+ struct hlist_node node;
+ /* List of sockets hashed to this bucket */
+ struct hlist_head owners;
+ /* bhash has twsk in owners, but bhash2 has twsk in
+ * deathrow not to add a member in struct sock_common.
+ */
+ struct hlist_head deathrow;
+};
+
+static inline struct net *ib_net(const struct inet_bind_bucket *ib)
+{
+ return read_pnet(&ib->ib_net);
+}
+
+static inline struct net *ib2_net(const struct inet_bind2_bucket *ib)
+{
+ return read_pnet(&ib->ib_net);
+}
+
+#define inet_bind_bucket_for_each(tb, head) \
+ hlist_for_each_entry(tb, head, node)
+
+struct inet_bind_hashbucket {
+ spinlock_t lock;
+ struct hlist_head chain;
+};
+
+/* Sockets can be hashed in established or listening table.
+ * We must use different 'nulls' end-of-chain value for all hash buckets :
+ * A socket might transition from ESTABLISH to LISTEN state without
+ * RCU grace period. A lookup in ehash table needs to handle this case.
+ */
+#define LISTENING_NULLS_BASE (1U << 29)
+struct inet_listen_hashbucket {
+ spinlock_t lock;
+ struct hlist_nulls_head nulls_head;
+};
+
+/* This is for listening sockets, thus all sockets which possess wildcards. */
+#define INET_LHTABLE_SIZE 32 /* Yes, really, this is all you need. */
+
+struct inet_hashinfo {
+ /* This is for sockets with full identity only. Sockets here will
+ * always be without wildcards and will have the following invariant:
+ *
+ * TCP_ESTABLISHED <= sk->sk_state < TCP_CLOSE
+ *
+ */
+ struct inet_ehash_bucket *ehash;
+ spinlock_t *ehash_locks;
+ unsigned int ehash_mask;
+ unsigned int ehash_locks_mask;
+
+ /* Ok, let's try this, I give up, we do need a local binding
+ * TCP hash as well as the others for fast bind/connect.
+ */
+ struct kmem_cache *bind_bucket_cachep;
+ /* This bind table is hashed by local port */
+ struct inet_bind_hashbucket *bhash;
+ struct kmem_cache *bind2_bucket_cachep;
+ /* This bind table is hashed by local port and sk->sk_rcv_saddr (ipv4)
+ * or sk->sk_v6_rcv_saddr (ipv6). This 2nd bind table is used
+ * primarily for expediting bind conflict resolution.
+ */
+ struct inet_bind_hashbucket *bhash2;
+ unsigned int bhash_size;
+
+ /* The 2nd listener table hashed by local port and address */
+ unsigned int lhash2_mask;
+ struct inet_listen_hashbucket *lhash2;
+
+ bool pernet;
+};
+
+static inline struct inet_hashinfo *tcp_or_dccp_get_hashinfo(const struct sock *sk)
+{
+#if IS_ENABLED(CONFIG_IP_DCCP)
+ return sk->sk_prot->h.hashinfo ? :
+ sock_net(sk)->ipv4.tcp_death_row.hashinfo;
+#else
+ return sock_net(sk)->ipv4.tcp_death_row.hashinfo;
+#endif
+}
+
+static inline struct inet_listen_hashbucket *
+inet_lhash2_bucket(struct inet_hashinfo *h, u32 hash)
+{
+ return &h->lhash2[hash & h->lhash2_mask];
+}
+
+static inline struct inet_ehash_bucket *inet_ehash_bucket(
+ struct inet_hashinfo *hashinfo,
+ unsigned int hash)
+{
+ return &hashinfo->ehash[hash & hashinfo->ehash_mask];
+}
+
+static inline spinlock_t *inet_ehash_lockp(
+ struct inet_hashinfo *hashinfo,
+ unsigned int hash)
+{
+ return &hashinfo->ehash_locks[hash & hashinfo->ehash_locks_mask];
+}
+
+int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo);
+
+static inline void inet_hashinfo2_free_mod(struct inet_hashinfo *h)
+{
+ kfree(h->lhash2);
+ h->lhash2 = NULL;
+}
+
+static inline void inet_ehash_locks_free(struct inet_hashinfo *hashinfo)
+{
+ kvfree(hashinfo->ehash_locks);
+ hashinfo->ehash_locks = NULL;
+}
+
+struct inet_hashinfo *inet_pernet_hashinfo_alloc(struct inet_hashinfo *hashinfo,
+ unsigned int ehash_entries);
+void inet_pernet_hashinfo_free(struct inet_hashinfo *hashinfo);
+
+struct inet_bind_bucket *
+inet_bind_bucket_create(struct kmem_cache *cachep, struct net *net,
+ struct inet_bind_hashbucket *head,
+ const unsigned short snum, int l3mdev);
+void inet_bind_bucket_destroy(struct kmem_cache *cachep,
+ struct inet_bind_bucket *tb);
+
+bool inet_bind_bucket_match(const struct inet_bind_bucket *tb,
+ const struct net *net, unsigned short port,
+ int l3mdev);
+
+struct inet_bind2_bucket *
+inet_bind2_bucket_create(struct kmem_cache *cachep, struct net *net,
+ struct inet_bind_hashbucket *head,
+ unsigned short port, int l3mdev,
+ const struct sock *sk);
+
+void inet_bind2_bucket_destroy(struct kmem_cache *cachep,
+ struct inet_bind2_bucket *tb);
+
+struct inet_bind2_bucket *
+inet_bind2_bucket_find(const struct inet_bind_hashbucket *head,
+ const struct net *net,
+ unsigned short port, int l3mdev,
+ const struct sock *sk);
+
+bool inet_bind2_bucket_match_addr_any(const struct inet_bind2_bucket *tb,
+ const struct net *net, unsigned short port,
+ int l3mdev, const struct sock *sk);
+
+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);
+}
+
+static inline struct inet_bind_hashbucket *
+inet_bhashfn_portaddr(const struct inet_hashinfo *hinfo, const struct sock *sk,
+ const struct net *net, unsigned short port)
+{
+ u32 hash;
+
+#if IS_ENABLED(CONFIG_IPV6)
+ if (sk->sk_family == AF_INET6)
+ hash = ipv6_portaddr_hash(net, &sk->sk_v6_rcv_saddr, port);
+ else
+#endif
+ hash = ipv4_portaddr_hash(net, sk->sk_rcv_saddr, port);
+ return &hinfo->bhash2[hash & (hinfo->bhash_size - 1)];
+}
+
+struct inet_bind_hashbucket *
+inet_bhash2_addr_any_hashbucket(const struct sock *sk, const struct net *net, int port);
+
+/* This should be called whenever a socket's sk_rcv_saddr (ipv4) or
+ * sk_v6_rcv_saddr (ipv6) changes after it has been binded. The socket's
+ * rcv_saddr field should already have been updated when this is called.
+ */
+int inet_bhash2_update_saddr(struct sock *sk, void *saddr, int family);
+void inet_bhash2_reset_saddr(struct sock *sk);
+
+void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
+ struct inet_bind2_bucket *tb2, unsigned short port);
+
+/* Caller must disable local BH processing. */
+int __inet_inherit_port(const struct sock *sk, struct sock *child);
+
+void inet_put_port(struct sock *sk);
+
+void inet_hashinfo2_init(struct inet_hashinfo *h, const char *name,
+ unsigned long numentries, int scale,
+ unsigned long low_limit,
+ unsigned long high_limit);
+int inet_hashinfo2_init_mod(struct inet_hashinfo *h);
+
+bool inet_ehash_insert(struct sock *sk, struct sock *osk, bool *found_dup_sk);
+bool inet_ehash_nolisten(struct sock *sk, struct sock *osk,
+ bool *found_dup_sk);
+int __inet_hash(struct sock *sk, struct sock *osk);
+int inet_hash(struct sock *sk);
+void inet_unhash(struct sock *sk);
+
+struct sock *__inet_lookup_listener(struct net *net,
+ struct inet_hashinfo *hashinfo,
+ struct sk_buff *skb, int doff,
+ const __be32 saddr, const __be16 sport,
+ const __be32 daddr,
+ const unsigned short hnum,
+ const int dif, const int sdif);
+
+static inline struct sock *inet_lookup_listener(struct net *net,
+ struct inet_hashinfo *hashinfo,
+ struct sk_buff *skb, int doff,
+ __be32 saddr, __be16 sport,
+ __be32 daddr, __be16 dport, int dif, int sdif)
+{
+ return __inet_lookup_listener(net, hashinfo, skb, doff, saddr, sport,
+ daddr, ntohs(dport), dif, sdif);
+}
+
+/* Socket demux engine toys. */
+/* What happens here is ugly; there's a pair of adjacent fields in
+ struct inet_sock; __be16 dport followed by __u16 num. We want to
+ search by pair, so we combine the keys into a single 32bit value
+ and compare with 32bit value read from &...->dport. Let's at least
+ make sure that it's not mixed with anything else...
+ On 64bit targets we combine comparisons with pair of adjacent __be32
+ fields in the same way.
+*/
+#ifdef __BIG_ENDIAN
+#define INET_COMBINED_PORTS(__sport, __dport) \
+ ((__force __portpair)(((__force __u32)(__be16)(__sport) << 16) | (__u32)(__dport)))
+#else /* __LITTLE_ENDIAN */
+#define INET_COMBINED_PORTS(__sport, __dport) \
+ ((__force __portpair)(((__u32)(__dport) << 16) | (__force __u32)(__be16)(__sport)))
+#endif
+
+#ifdef __BIG_ENDIAN
+#define INET_ADDR_COOKIE(__name, __saddr, __daddr) \
+ const __addrpair __name = (__force __addrpair) ( \
+ (((__force __u64)(__be32)(__saddr)) << 32) | \
+ ((__force __u64)(__be32)(__daddr)))
+#else /* __LITTLE_ENDIAN */
+#define INET_ADDR_COOKIE(__name, __saddr, __daddr) \
+ const __addrpair __name = (__force __addrpair) ( \
+ (((__force __u64)(__be32)(__daddr)) << 32) | \
+ ((__force __u64)(__be32)(__saddr)))
+#endif /* __BIG_ENDIAN */
+
+static inline bool inet_match(struct net *net, const struct sock *sk,
+ const __addrpair cookie, const __portpair ports,
+ int dif, int sdif)
+{
+ if (!net_eq(sock_net(sk), net) ||
+ sk->sk_portpair != ports ||
+ sk->sk_addrpair != cookie)
+ return false;
+
+ /* READ_ONCE() paired with WRITE_ONCE() in sock_bindtoindex_locked() */
+ return inet_sk_bound_dev_eq(net, READ_ONCE(sk->sk_bound_dev_if), dif,
+ sdif);
+}
+
+/* Sockets in TCP_CLOSE state are _always_ taken out of the hash, so we need
+ * not check it for lookups anymore, thanks Alexey. -DaveM
+ */
+struct sock *__inet_lookup_established(struct net *net,
+ struct inet_hashinfo *hashinfo,
+ const __be32 saddr, const __be16 sport,
+ const __be32 daddr, const u16 hnum,
+ const int dif, const int sdif);
+
+static inline struct sock *
+ inet_lookup_established(struct net *net, struct inet_hashinfo *hashinfo,
+ const __be32 saddr, const __be16 sport,
+ const __be32 daddr, const __be16 dport,
+ const int dif)
+{
+ return __inet_lookup_established(net, hashinfo, saddr, sport, daddr,
+ ntohs(dport), dif, 0);
+}
+
+static inline struct sock *__inet_lookup(struct net *net,
+ struct inet_hashinfo *hashinfo,
+ struct sk_buff *skb, int doff,
+ const __be32 saddr, const __be16 sport,
+ const __be32 daddr, const __be16 dport,
+ const int dif, const int sdif,
+ bool *refcounted)
+{
+ u16 hnum = ntohs(dport);
+ struct sock *sk;
+
+ sk = __inet_lookup_established(net, hashinfo, saddr, sport,
+ daddr, hnum, dif, sdif);
+ *refcounted = true;
+ if (sk)
+ return sk;
+ *refcounted = false;
+ return __inet_lookup_listener(net, hashinfo, skb, doff, saddr,
+ sport, daddr, hnum, dif, sdif);
+}
+
+static inline struct sock *inet_lookup(struct net *net,
+ struct inet_hashinfo *hashinfo,
+ struct sk_buff *skb, int doff,
+ const __be32 saddr, const __be16 sport,
+ const __be32 daddr, const __be16 dport,
+ const int dif)
+{
+ struct sock *sk;
+ bool refcounted;
+
+ sk = __inet_lookup(net, hashinfo, skb, doff, saddr, sport, daddr,
+ dport, dif, 0, &refcounted);
+
+ if (sk && !refcounted && !refcount_inc_not_zero(&sk->sk_refcnt))
+ sk = NULL;
+ return sk;
+}
+
+static inline struct sock *__inet_lookup_skb(struct inet_hashinfo *hashinfo,
+ struct sk_buff *skb,
+ int doff,
+ const __be16 sport,
+ const __be16 dport,
+ const int sdif,
+ bool *refcounted)
+{
+ struct sock *sk = skb_steal_sock(skb, refcounted);
+ const struct iphdr *iph = ip_hdr(skb);
+
+ if (sk)
+ return sk;
+
+ return __inet_lookup(dev_net(skb_dst(skb)->dev), hashinfo, skb,
+ doff, iph->saddr, sport,
+ iph->daddr, dport, inet_iif(skb), sdif,
+ refcounted);
+}
+
+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, u64 port_offset,
+ int (*check_established)(struct inet_timewait_death_row *,
+ struct sock *, __u16,
+ struct inet_timewait_sock **));
+
+int inet_hash_connect(struct inet_timewait_death_row *death_row,
+ struct sock *sk);
+#endif /* _INET_HASHTABLES_H */
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