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sock_map.c
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sock_map.c
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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2017 - 2018 Covalent IO, Inc. http://covalent.io */
#include <linux/bpf.h>
#include <linux/btf_ids.h>
#include <linux/filter.h>
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/net.h>
#include <linux/workqueue.h>
#include <linux/skmsg.h>
#include <linux/list.h>
#include <linux/jhash.h>
#include <linux/sock_diag.h>
#include <net/udp.h>
struct bpf_stab {
struct bpf_map map;
struct sock **sks;
struct sk_psock_progs progs;
raw_spinlock_t lock;
};
#define SOCK_CREATE_FLAG_MASK \
(BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)
static int sock_map_prog_update(struct bpf_map *map, struct bpf_prog *prog,
struct bpf_prog *old, u32 which);
static struct sk_psock_progs *sock_map_progs(struct bpf_map *map);
static struct bpf_map *sock_map_alloc(union bpf_attr *attr)
{
struct bpf_stab *stab;
if (!capable(CAP_NET_ADMIN))
return ERR_PTR(-EPERM);
if (attr->max_entries == 0 ||
attr->key_size != 4 ||
(attr->value_size != sizeof(u32) &&
attr->value_size != sizeof(u64)) ||
attr->map_flags & ~SOCK_CREATE_FLAG_MASK)
return ERR_PTR(-EINVAL);
stab = kzalloc(sizeof(*stab), GFP_USER | __GFP_ACCOUNT);
if (!stab)
return ERR_PTR(-ENOMEM);
bpf_map_init_from_attr(&stab->map, attr);
raw_spin_lock_init(&stab->lock);
stab->sks = bpf_map_area_alloc((u64) stab->map.max_entries *
sizeof(struct sock *),
stab->map.numa_node);
if (!stab->sks) {
kfree(stab);
return ERR_PTR(-ENOMEM);
}
return &stab->map;
}
int sock_map_get_from_fd(const union bpf_attr *attr, struct bpf_prog *prog)
{
u32 ufd = attr->target_fd;
struct bpf_map *map;
struct fd f;
int ret;
if (attr->attach_flags || attr->replace_bpf_fd)
return -EINVAL;
f = fdget(ufd);
map = __bpf_map_get(f);
if (IS_ERR(map))
return PTR_ERR(map);
ret = sock_map_prog_update(map, prog, NULL, attr->attach_type);
fdput(f);
return ret;
}
int sock_map_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype)
{
u32 ufd = attr->target_fd;
struct bpf_prog *prog;
struct bpf_map *map;
struct fd f;
int ret;
if (attr->attach_flags || attr->replace_bpf_fd)
return -EINVAL;
f = fdget(ufd);
map = __bpf_map_get(f);
if (IS_ERR(map))
return PTR_ERR(map);
prog = bpf_prog_get(attr->attach_bpf_fd);
if (IS_ERR(prog)) {
ret = PTR_ERR(prog);
goto put_map;
}
if (prog->type != ptype) {
ret = -EINVAL;
goto put_prog;
}
ret = sock_map_prog_update(map, NULL, prog, attr->attach_type);
put_prog:
bpf_prog_put(prog);
put_map:
fdput(f);
return ret;
}
static void sock_map_sk_acquire(struct sock *sk)
__acquires(&sk->sk_lock.slock)
{
lock_sock(sk);
preempt_disable();
rcu_read_lock();
}
static void sock_map_sk_release(struct sock *sk)
__releases(&sk->sk_lock.slock)
{
rcu_read_unlock();
preempt_enable();
release_sock(sk);
}
static void sock_map_add_link(struct sk_psock *psock,
struct sk_psock_link *link,
struct bpf_map *map, void *link_raw)
{
link->link_raw = link_raw;
link->map = map;
spin_lock_bh(&psock->link_lock);
list_add_tail(&link->list, &psock->link);
spin_unlock_bh(&psock->link_lock);
}
static void sock_map_del_link(struct sock *sk,
struct sk_psock *psock, void *link_raw)
{
bool strp_stop = false, verdict_stop = false;
struct sk_psock_link *link, *tmp;
spin_lock_bh(&psock->link_lock);
list_for_each_entry_safe(link, tmp, &psock->link, list) {
if (link->link_raw == link_raw) {
struct bpf_map *map = link->map;
struct bpf_stab *stab = container_of(map, struct bpf_stab,
map);
if (psock->saved_data_ready && stab->progs.stream_parser)
strp_stop = true;
if (psock->saved_data_ready && stab->progs.stream_verdict)
verdict_stop = true;
if (psock->saved_data_ready && stab->progs.skb_verdict)
verdict_stop = true;
list_del(&link->list);
sk_psock_free_link(link);
}
}
spin_unlock_bh(&psock->link_lock);
if (strp_stop || verdict_stop) {
write_lock_bh(&sk->sk_callback_lock);
if (strp_stop)
sk_psock_stop_strp(sk, psock);
if (verdict_stop)
sk_psock_stop_verdict(sk, psock);
if (psock->psock_update_sk_prot)
psock->psock_update_sk_prot(sk, psock, false);
write_unlock_bh(&sk->sk_callback_lock);
}
}
static void sock_map_unref(struct sock *sk, void *link_raw)
{
struct sk_psock *psock = sk_psock(sk);
if (likely(psock)) {
sock_map_del_link(sk, psock, link_raw);
sk_psock_put(sk, psock);
}
}
static int sock_map_init_proto(struct sock *sk, struct sk_psock *psock)
{
if (!sk->sk_prot->psock_update_sk_prot)
return -EINVAL;
psock->psock_update_sk_prot = sk->sk_prot->psock_update_sk_prot;
return sk->sk_prot->psock_update_sk_prot(sk, psock, false);
}
static struct sk_psock *sock_map_psock_get_checked(struct sock *sk)
{
struct sk_psock *psock;
rcu_read_lock();
psock = sk_psock(sk);
if (psock) {
if (sk->sk_prot->close != sock_map_close) {
psock = ERR_PTR(-EBUSY);
goto out;
}
if (!refcount_inc_not_zero(&psock->refcnt))
psock = ERR_PTR(-EBUSY);
}
out:
rcu_read_unlock();
return psock;
}
static int sock_map_link(struct bpf_map *map, struct sock *sk)
{
struct sk_psock_progs *progs = sock_map_progs(map);
struct bpf_prog *stream_verdict = NULL;
struct bpf_prog *stream_parser = NULL;
struct bpf_prog *skb_verdict = NULL;
struct bpf_prog *msg_parser = NULL;
struct sk_psock *psock;
int ret;
stream_verdict = READ_ONCE(progs->stream_verdict);
if (stream_verdict) {
stream_verdict = bpf_prog_inc_not_zero(stream_verdict);
if (IS_ERR(stream_verdict))
return PTR_ERR(stream_verdict);
}
stream_parser = READ_ONCE(progs->stream_parser);
if (stream_parser) {
stream_parser = bpf_prog_inc_not_zero(stream_parser);
if (IS_ERR(stream_parser)) {
ret = PTR_ERR(stream_parser);
goto out_put_stream_verdict;
}
}
msg_parser = READ_ONCE(progs->msg_parser);
if (msg_parser) {
msg_parser = bpf_prog_inc_not_zero(msg_parser);
if (IS_ERR(msg_parser)) {
ret = PTR_ERR(msg_parser);
goto out_put_stream_parser;
}
}
skb_verdict = READ_ONCE(progs->skb_verdict);
if (skb_verdict) {
skb_verdict = bpf_prog_inc_not_zero(skb_verdict);
if (IS_ERR(skb_verdict)) {
ret = PTR_ERR(skb_verdict);
goto out_put_msg_parser;
}
}
psock = sock_map_psock_get_checked(sk);
if (IS_ERR(psock)) {
ret = PTR_ERR(psock);
goto out_progs;
}
if (psock) {
if ((msg_parser && READ_ONCE(psock->progs.msg_parser)) ||
(stream_parser && READ_ONCE(psock->progs.stream_parser)) ||
(skb_verdict && READ_ONCE(psock->progs.skb_verdict)) ||
(skb_verdict && READ_ONCE(psock->progs.stream_verdict)) ||
(stream_verdict && READ_ONCE(psock->progs.skb_verdict)) ||
(stream_verdict && READ_ONCE(psock->progs.stream_verdict))) {
sk_psock_put(sk, psock);
ret = -EBUSY;
goto out_progs;
}
} else {
psock = sk_psock_init(sk, map->numa_node);
if (IS_ERR(psock)) {
ret = PTR_ERR(psock);
goto out_progs;
}
}
if (msg_parser)
psock_set_prog(&psock->progs.msg_parser, msg_parser);
if (stream_parser)
psock_set_prog(&psock->progs.stream_parser, stream_parser);
if (stream_verdict)
psock_set_prog(&psock->progs.stream_verdict, stream_verdict);
if (skb_verdict)
psock_set_prog(&psock->progs.skb_verdict, skb_verdict);
/* msg_* and stream_* programs references tracked in psock after this
* point. Reference dec and cleanup will occur through psock destructor
*/
ret = sock_map_init_proto(sk, psock);
if (ret < 0) {
sk_psock_put(sk, psock);
goto out;
}
write_lock_bh(&sk->sk_callback_lock);
if (stream_parser && stream_verdict && !psock->saved_data_ready) {
ret = sk_psock_init_strp(sk, psock);
if (ret) {
write_unlock_bh(&sk->sk_callback_lock);
sk_psock_put(sk, psock);
goto out;
}
sk_psock_start_strp(sk, psock);
} else if (!stream_parser && stream_verdict && !psock->saved_data_ready) {
sk_psock_start_verdict(sk,psock);
} else if (!stream_verdict && skb_verdict && !psock->saved_data_ready) {
sk_psock_start_verdict(sk, psock);
}
write_unlock_bh(&sk->sk_callback_lock);
return 0;
out_progs:
if (skb_verdict)
bpf_prog_put(skb_verdict);
out_put_msg_parser:
if (msg_parser)
bpf_prog_put(msg_parser);
out_put_stream_parser:
if (stream_parser)
bpf_prog_put(stream_parser);
out_put_stream_verdict:
if (stream_verdict)
bpf_prog_put(stream_verdict);
out:
return ret;
}
static void sock_map_free(struct bpf_map *map)
{
struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
int i;
/* After the sync no updates or deletes will be in-flight so it
* is safe to walk map and remove entries without risking a race
* in EEXIST update case.
*/
synchronize_rcu();
for (i = 0; i < stab->map.max_entries; i++) {
struct sock **psk = &stab->sks[i];
struct sock *sk;
sk = xchg(psk, NULL);
if (sk) {
lock_sock(sk);
rcu_read_lock();
sock_map_unref(sk, psk);
rcu_read_unlock();
release_sock(sk);
}
}
/* wait for psock readers accessing its map link */
synchronize_rcu();
bpf_map_area_free(stab->sks);
kfree(stab);
}
static void sock_map_release_progs(struct bpf_map *map)
{
psock_progs_drop(&container_of(map, struct bpf_stab, map)->progs);
}
static struct sock *__sock_map_lookup_elem(struct bpf_map *map, u32 key)
{
struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
WARN_ON_ONCE(!rcu_read_lock_held());
if (unlikely(key >= map->max_entries))
return NULL;
return READ_ONCE(stab->sks[key]);
}
static void *sock_map_lookup(struct bpf_map *map, void *key)
{
struct sock *sk;
sk = __sock_map_lookup_elem(map, *(u32 *)key);
if (!sk)
return NULL;
if (sk_is_refcounted(sk) && !refcount_inc_not_zero(&sk->sk_refcnt))
return NULL;
return sk;
}
static void *sock_map_lookup_sys(struct bpf_map *map, void *key)
{
struct sock *sk;
if (map->value_size != sizeof(u64))
return ERR_PTR(-ENOSPC);
sk = __sock_map_lookup_elem(map, *(u32 *)key);
if (!sk)
return ERR_PTR(-ENOENT);
__sock_gen_cookie(sk);
return &sk->sk_cookie;
}
static int __sock_map_delete(struct bpf_stab *stab, struct sock *sk_test,
struct sock **psk)
{
struct sock *sk;
int err = 0;
raw_spin_lock_bh(&stab->lock);
sk = *psk;
if (!sk_test || sk_test == sk)
sk = xchg(psk, NULL);
if (likely(sk))
sock_map_unref(sk, psk);
else
err = -EINVAL;
raw_spin_unlock_bh(&stab->lock);
return err;
}
static void sock_map_delete_from_link(struct bpf_map *map, struct sock *sk,
void *link_raw)
{
struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
__sock_map_delete(stab, sk, link_raw);
}
static int sock_map_delete_elem(struct bpf_map *map, void *key)
{
struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
u32 i = *(u32 *)key;
struct sock **psk;
if (unlikely(i >= map->max_entries))
return -EINVAL;
psk = &stab->sks[i];
return __sock_map_delete(stab, NULL, psk);
}
static int sock_map_get_next_key(struct bpf_map *map, void *key, void *next)
{
struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
u32 i = key ? *(u32 *)key : U32_MAX;
u32 *key_next = next;
if (i == stab->map.max_entries - 1)
return -ENOENT;
if (i >= stab->map.max_entries)
*key_next = 0;
else
*key_next = i + 1;
return 0;
}
static int sock_map_update_common(struct bpf_map *map, u32 idx,
struct sock *sk, u64 flags)
{
struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
struct sk_psock_link *link;
struct sk_psock *psock;
struct sock *osk;
int ret;
WARN_ON_ONCE(!rcu_read_lock_held());
if (unlikely(flags > BPF_EXIST))
return -EINVAL;
if (unlikely(idx >= map->max_entries))
return -E2BIG;
link = sk_psock_init_link();
if (!link)
return -ENOMEM;
ret = sock_map_link(map, sk);
if (ret < 0)
goto out_free;
psock = sk_psock(sk);
WARN_ON_ONCE(!psock);
raw_spin_lock_bh(&stab->lock);
osk = stab->sks[idx];
if (osk && flags == BPF_NOEXIST) {
ret = -EEXIST;
goto out_unlock;
} else if (!osk && flags == BPF_EXIST) {
ret = -ENOENT;
goto out_unlock;
}
sock_map_add_link(psock, link, map, &stab->sks[idx]);
stab->sks[idx] = sk;
if (osk)
sock_map_unref(osk, &stab->sks[idx]);
raw_spin_unlock_bh(&stab->lock);
return 0;
out_unlock:
raw_spin_unlock_bh(&stab->lock);
if (psock)
sk_psock_put(sk, psock);
out_free:
sk_psock_free_link(link);
return ret;
}
static bool sock_map_op_okay(const struct bpf_sock_ops_kern *ops)
{
return ops->op == BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB ||
ops->op == BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB ||
ops->op == BPF_SOCK_OPS_TCP_LISTEN_CB;
}
static bool sock_map_redirect_allowed(const struct sock *sk)
{
if (sk_is_tcp(sk))
return sk->sk_state != TCP_LISTEN;
else
return sk->sk_state == TCP_ESTABLISHED;
}
static bool sock_map_sk_is_suitable(const struct sock *sk)
{
return !!sk->sk_prot->psock_update_sk_prot;
}
static bool sock_map_sk_state_allowed(const struct sock *sk)
{
if (sk_is_tcp(sk))
return (1 << sk->sk_state) & (TCPF_ESTABLISHED | TCPF_LISTEN);
return true;
}
static int sock_hash_update_common(struct bpf_map *map, void *key,
struct sock *sk, u64 flags);
int sock_map_update_elem_sys(struct bpf_map *map, void *key, void *value,
u64 flags)
{
struct socket *sock;
struct sock *sk;
int ret;
u64 ufd;
if (map->value_size == sizeof(u64))
ufd = *(u64 *)value;
else
ufd = *(u32 *)value;
if (ufd > S32_MAX)
return -EINVAL;
sock = sockfd_lookup(ufd, &ret);
if (!sock)
return ret;
sk = sock->sk;
if (!sk) {
ret = -EINVAL;
goto out;
}
if (!sock_map_sk_is_suitable(sk)) {
ret = -EOPNOTSUPP;
goto out;
}
sock_map_sk_acquire(sk);
if (!sock_map_sk_state_allowed(sk))
ret = -EOPNOTSUPP;
else if (map->map_type == BPF_MAP_TYPE_SOCKMAP)
ret = sock_map_update_common(map, *(u32 *)key, sk, flags);
else
ret = sock_hash_update_common(map, key, sk, flags);
sock_map_sk_release(sk);
out:
sockfd_put(sock);
return ret;
}
static int sock_map_update_elem(struct bpf_map *map, void *key,
void *value, u64 flags)
{
struct sock *sk = (struct sock *)value;
int ret;
if (unlikely(!sk || !sk_fullsock(sk)))
return -EINVAL;
if (!sock_map_sk_is_suitable(sk))
return -EOPNOTSUPP;
local_bh_disable();
bh_lock_sock(sk);
if (!sock_map_sk_state_allowed(sk))
ret = -EOPNOTSUPP;
else if (map->map_type == BPF_MAP_TYPE_SOCKMAP)
ret = sock_map_update_common(map, *(u32 *)key, sk, flags);
else
ret = sock_hash_update_common(map, key, sk, flags);
bh_unlock_sock(sk);
local_bh_enable();
return ret;
}
BPF_CALL_4(bpf_sock_map_update, struct bpf_sock_ops_kern *, sops,
struct bpf_map *, map, void *, key, u64, flags)
{
WARN_ON_ONCE(!rcu_read_lock_held());
if (likely(sock_map_sk_is_suitable(sops->sk) &&
sock_map_op_okay(sops)))
return sock_map_update_common(map, *(u32 *)key, sops->sk,
flags);
return -EOPNOTSUPP;
}
const struct bpf_func_proto bpf_sock_map_update_proto = {
.func = bpf_sock_map_update,
.gpl_only = false,
.pkt_access = true,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_CTX,
.arg2_type = ARG_CONST_MAP_PTR,
.arg3_type = ARG_PTR_TO_MAP_KEY,
.arg4_type = ARG_ANYTHING,
};
BPF_CALL_4(bpf_sk_redirect_map, struct sk_buff *, skb,
struct bpf_map *, map, u32, key, u64, flags)
{
struct sock *sk;
if (unlikely(flags & ~(BPF_F_INGRESS)))
return SK_DROP;
sk = __sock_map_lookup_elem(map, key);
if (unlikely(!sk || !sock_map_redirect_allowed(sk)))
return SK_DROP;
skb_bpf_set_redir(skb, sk, flags & BPF_F_INGRESS);
return SK_PASS;
}
const struct bpf_func_proto bpf_sk_redirect_map_proto = {
.func = bpf_sk_redirect_map,
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_CTX,
.arg2_type = ARG_CONST_MAP_PTR,
.arg3_type = ARG_ANYTHING,
.arg4_type = ARG_ANYTHING,
};
BPF_CALL_4(bpf_msg_redirect_map, struct sk_msg *, msg,
struct bpf_map *, map, u32, key, u64, flags)
{
struct sock *sk;
if (unlikely(flags & ~(BPF_F_INGRESS)))
return SK_DROP;
sk = __sock_map_lookup_elem(map, key);
if (unlikely(!sk || !sock_map_redirect_allowed(sk)))
return SK_DROP;
msg->flags = flags;
msg->sk_redir = sk;
return SK_PASS;
}
const struct bpf_func_proto bpf_msg_redirect_map_proto = {
.func = bpf_msg_redirect_map,
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_CTX,
.arg2_type = ARG_CONST_MAP_PTR,
.arg3_type = ARG_ANYTHING,
.arg4_type = ARG_ANYTHING,
};
struct sock_map_seq_info {
struct bpf_map *map;
struct sock *sk;
u32 index;
};
struct bpf_iter__sockmap {
__bpf_md_ptr(struct bpf_iter_meta *, meta);
__bpf_md_ptr(struct bpf_map *, map);
__bpf_md_ptr(void *, key);
__bpf_md_ptr(struct sock *, sk);
};
DEFINE_BPF_ITER_FUNC(sockmap, struct bpf_iter_meta *meta,
struct bpf_map *map, void *key,
struct sock *sk)
static void *sock_map_seq_lookup_elem(struct sock_map_seq_info *info)
{
if (unlikely(info->index >= info->map->max_entries))
return NULL;
info->sk = __sock_map_lookup_elem(info->map, info->index);
/* can't return sk directly, since that might be NULL */
return info;
}
static void *sock_map_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(rcu)
{
struct sock_map_seq_info *info = seq->private;
if (*pos == 0)
++*pos;
/* pairs with sock_map_seq_stop */
rcu_read_lock();
return sock_map_seq_lookup_elem(info);
}
static void *sock_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
__must_hold(rcu)
{
struct sock_map_seq_info *info = seq->private;
++*pos;
++info->index;
return sock_map_seq_lookup_elem(info);
}
static int sock_map_seq_show(struct seq_file *seq, void *v)
__must_hold(rcu)
{
struct sock_map_seq_info *info = seq->private;
struct bpf_iter__sockmap ctx = {};
struct bpf_iter_meta meta;
struct bpf_prog *prog;
meta.seq = seq;
prog = bpf_iter_get_info(&meta, !v);
if (!prog)
return 0;
ctx.meta = &meta;
ctx.map = info->map;
if (v) {
ctx.key = &info->index;
ctx.sk = info->sk;
}
return bpf_iter_run_prog(prog, &ctx);
}
static void sock_map_seq_stop(struct seq_file *seq, void *v)
__releases(rcu)
{
if (!v)
(void)sock_map_seq_show(seq, NULL);
/* pairs with sock_map_seq_start */
rcu_read_unlock();
}
static const struct seq_operations sock_map_seq_ops = {
.start = sock_map_seq_start,
.next = sock_map_seq_next,
.stop = sock_map_seq_stop,
.show = sock_map_seq_show,
};
static int sock_map_init_seq_private(void *priv_data,
struct bpf_iter_aux_info *aux)
{
struct sock_map_seq_info *info = priv_data;
info->map = aux->map;
return 0;
}
static const struct bpf_iter_seq_info sock_map_iter_seq_info = {
.seq_ops = &sock_map_seq_ops,
.init_seq_private = sock_map_init_seq_private,
.seq_priv_size = sizeof(struct sock_map_seq_info),
};
static int sock_map_btf_id;
const struct bpf_map_ops sock_map_ops = {
.map_meta_equal = bpf_map_meta_equal,
.map_alloc = sock_map_alloc,
.map_free = sock_map_free,
.map_get_next_key = sock_map_get_next_key,
.map_lookup_elem_sys_only = sock_map_lookup_sys,
.map_update_elem = sock_map_update_elem,
.map_delete_elem = sock_map_delete_elem,
.map_lookup_elem = sock_map_lookup,
.map_release_uref = sock_map_release_progs,
.map_check_btf = map_check_no_btf,
.map_btf_name = "bpf_stab",
.map_btf_id = &sock_map_btf_id,
.iter_seq_info = &sock_map_iter_seq_info,
};
struct bpf_shtab_elem {
struct rcu_head rcu;
u32 hash;
struct sock *sk;
struct hlist_node node;
u8 key[];
};
struct bpf_shtab_bucket {
struct hlist_head head;
raw_spinlock_t lock;
};
struct bpf_shtab {
struct bpf_map map;
struct bpf_shtab_bucket *buckets;
u32 buckets_num;
u32 elem_size;
struct sk_psock_progs progs;
atomic_t count;
};
static inline u32 sock_hash_bucket_hash(const void *key, u32 len)
{
return jhash(key, len, 0);
}
static struct bpf_shtab_bucket *sock_hash_select_bucket(struct bpf_shtab *htab,
u32 hash)
{
return &htab->buckets[hash & (htab->buckets_num - 1)];
}
static struct bpf_shtab_elem *
sock_hash_lookup_elem_raw(struct hlist_head *head, u32 hash, void *key,
u32 key_size)
{
struct bpf_shtab_elem *elem;
hlist_for_each_entry_rcu(elem, head, node) {
if (elem->hash == hash &&
!memcmp(&elem->key, key, key_size))
return elem;
}
return NULL;
}
static struct sock *__sock_hash_lookup_elem(struct bpf_map *map, void *key)
{
struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map);
u32 key_size = map->key_size, hash;
struct bpf_shtab_bucket *bucket;
struct bpf_shtab_elem *elem;
WARN_ON_ONCE(!rcu_read_lock_held());
hash = sock_hash_bucket_hash(key, key_size);
bucket = sock_hash_select_bucket(htab, hash);
elem = sock_hash_lookup_elem_raw(&bucket->head, hash, key, key_size);
return elem ? elem->sk : NULL;
}
static void sock_hash_free_elem(struct bpf_shtab *htab,
struct bpf_shtab_elem *elem)
{
atomic_dec(&htab->count);
kfree_rcu(elem, rcu);
}
static void sock_hash_delete_from_link(struct bpf_map *map, struct sock *sk,
void *link_raw)
{
struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map);
struct bpf_shtab_elem *elem_probe, *elem = link_raw;
struct bpf_shtab_bucket *bucket;
WARN_ON_ONCE(!rcu_read_lock_held());
bucket = sock_hash_select_bucket(htab, elem->hash);
/* elem may be deleted in parallel from the map, but access here
* is okay since it's going away only after RCU grace period.
* However, we need to check whether it's still present.
*/
raw_spin_lock_bh(&bucket->lock);
elem_probe = sock_hash_lookup_elem_raw(&bucket->head, elem->hash,
elem->key, map->key_size);
if (elem_probe && elem_probe == elem) {
hlist_del_rcu(&elem->node);
sock_map_unref(elem->sk, elem);
sock_hash_free_elem(htab, elem);
}
raw_spin_unlock_bh(&bucket->lock);
}
static int sock_hash_delete_elem(struct bpf_map *map, void *key)
{
struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map);
u32 hash, key_size = map->key_size;
struct bpf_shtab_bucket *bucket;
struct bpf_shtab_elem *elem;
int ret = -ENOENT;
hash = sock_hash_bucket_hash(key, key_size);
bucket = sock_hash_select_bucket(htab, hash);
raw_spin_lock_bh(&bucket->lock);
elem = sock_hash_lookup_elem_raw(&bucket->head, hash, key, key_size);
if (elem) {
hlist_del_rcu(&elem->node);
sock_map_unref(elem->sk, elem);
sock_hash_free_elem(htab, elem);
ret = 0;
}
raw_spin_unlock_bh(&bucket->lock);
return ret;
}
static struct bpf_shtab_elem *sock_hash_alloc_elem(struct bpf_shtab *htab,
void *key, u32 key_size,
u32 hash, struct sock *sk,
struct bpf_shtab_elem *old)
{
struct bpf_shtab_elem *new;
if (atomic_inc_return(&htab->count) > htab->map.max_entries) {
if (!old) {
atomic_dec(&htab->count);
return ERR_PTR(-E2BIG);
}
}
new = bpf_map_kmalloc_node(&htab->map, htab->elem_size,
GFP_ATOMIC | __GFP_NOWARN,
htab->map.numa_node);
if (!new) {
atomic_dec(&htab->count);
return ERR_PTR(-ENOMEM);
}
memcpy(new->key, key, key_size);
new->sk = sk;
new->hash = hash;
return new;
}
static int sock_hash_update_common(struct bpf_map *map, void *key,
struct sock *sk, u64 flags)
{
struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map);
u32 key_size = map->key_size, hash;
struct bpf_shtab_elem *elem, *elem_new;
struct bpf_shtab_bucket *bucket;
struct sk_psock_link *link;
struct sk_psock *psock;
int ret;
WARN_ON_ONCE(!rcu_read_lock_held());
if (unlikely(flags > BPF_EXIST))
return -EINVAL;
link = sk_psock_init_link();
if (!link)
return -ENOMEM;
ret = sock_map_link(map, sk);
if (ret < 0)
goto out_free;
psock = sk_psock(sk);
WARN_ON_ONCE(!psock);
hash = sock_hash_bucket_hash(key, key_size);
bucket = sock_hash_select_bucket(htab, hash);
raw_spin_lock_bh(&bucket->lock);
elem = sock_hash_lookup_elem_raw(&bucket->head, hash, key, key_size);
if (elem && flags == BPF_NOEXIST) {
ret = -EEXIST;
goto out_unlock;
} else if (!elem && flags == BPF_EXIST) {
ret = -ENOENT;
goto out_unlock;
}
elem_new = sock_hash_alloc_elem(htab, key, key_size, hash, sk, elem);
if (IS_ERR(elem_new)) {
ret = PTR_ERR(elem_new);