// 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 <[email protected]>
*/
#include <linux/module.h>
#include <linux/random.h>
#include <net/addrconf.h>
#include <net/hotdata.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>
#include <net/tcp.h>
u32 inet6_ehashfn(const struct net *net,
const struct in6_addr *laddr, const u16 lport,
const struct in6_addr *faddr, const __be16 fport)
{
u32 lhash, fhash;
net_get_random_once(&inet6_ehash_secret, sizeof(inet6_ehash_secret));
net_get_random_once(&tcp_ipv6_hash_secret, sizeof(tcp_ipv6_hash_secret));
lhash = (__force u32)laddr->s6_addr32[3];
fhash = __ipv6_addr_jhash(faddr, tcp_ipv6_hash_secret);
return __inet6_ehashfn(lhash, lport, fhash, fport,
inet6_ehash_secret + net_hash_mix(net));
}
EXPORT_SYMBOL_GPL(inet6_ehashfn);
/*
* 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(const 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, const 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;
}
/**
* inet6_lookup_reuseport() - execute reuseport logic on AF_INET6 socket if necessary.
* @net: network namespace.
* @sk: AF_INET6 socket, must be in TCP_LISTEN state for TCP or TCP_CLOSE for UDP.
* @skb: context for a potential SK_REUSEPORT program.
* @doff: header offset.
* @saddr: source address.
* @sport: source port.
* @daddr: destination address.
* @hnum: destination port in host byte order.
* @ehashfn: hash function used to generate the fallback hash.
*
* Return: NULL if sk doesn't have SO_REUSEPORT set, otherwise a pointer to
* the selected sock or an error.
*/
struct sock *inet6_lookup_reuseport(const 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,
inet6_ehashfn_t *ehashfn)
{
struct sock *reuse_sk = NULL;
u32 phash;
if (sk->sk_reuseport) {
phash = INDIRECT_CALL_INET(ehashfn, udp6_ehashfn, inet6_ehashfn,
net, daddr, hnum, saddr, sport);
reuse_sk = reuseport_select_sock(sk, phash, skb, doff);
}
return reuse_sk;
}
EXPORT_SYMBOL_GPL(inet6_lookup_reuseport);
/* called with rcu_read_lock() */
static struct sock *inet6_lhash2_lookup(const 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 = inet6_lookup_reuseport(net, sk, skb, doff,
saddr, sport, daddr, hnum, inet6_ehashfn);
if (result)
return result;
result = sk;
hiscore = score;
}
}
return result;
}
struct sock *inet6_lookup_run_sk_lookup(const struct net *net,
int protocol,
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,
inet6_ehashfn_t *ehashfn)
{
struct sock *sk, *reuse_sk;
bool no_reuseport;
no_reuseport = bpf_sk_lookup_run_v6(net, protocol, saddr, sport,
daddr, hnum, dif, &sk);
if (no_reuseport || IS_ERR_OR_NULL(sk))
return sk;
reuse_sk = inet6_lookup_reuseport(net, sk, skb, doff,
saddr, sport, daddr, hnum, ehashfn);
if (reuse_sk)
sk = reuse_sk;
return sk;
}
EXPORT_SYMBOL_GPL(inet6_lookup_run_sk_lookup);
struct sock *inet6_lookup_listener(const 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) &&
hashinfo == net->ipv4.tcp_death_row.hashinfo) {
result = inet6_lookup_run_sk_lookup(net, IPPROTO_TCP, skb, doff,
saddr, sport, daddr, hnum, dif,
inet6_ehashfn);
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(const 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 (sk->sk_protocol == IPPROTO_TCP &&
tcp_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);
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