blob: a927e89dad6e9591066c3a87afc497a196ebd887 [file] [log] [blame]
/* Copyright (c) 2017 Covalent IO, Inc. http://covalent.io
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
/* A BPF sock_map is used to store sock objects. This is primarly used
* for doing socket redirect with BPF helper routines.
*
* A sock map may have BPF programs attached to it, currently a program
* used to parse packets and a program to provide a verdict and redirect
* decision on the packet are supported. Any programs attached to a sock
* map are inherited by sock objects when they are added to the map. If
* no BPF programs are attached the sock object may only be used for sock
* redirect.
*
* A sock object may be in multiple maps, but can only inherit a single
* parse or verdict program. If adding a sock object to a map would result
* in having multiple parsing programs the update will return an EBUSY error.
*
* For reference this program is similar to devmap used in XDP context
* reviewing these together may be useful. For an example please review
* ./samples/bpf/sockmap/.
*/
#include <linux/bpf.h>
#include <net/sock.h>
#include <linux/filter.h>
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/kernel.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/workqueue.h>
#include <linux/list.h>
#include <net/strparser.h>
#include <net/tcp.h>
#define SOCK_CREATE_FLAG_MASK \
(BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)
struct bpf_stab {
struct bpf_map map;
struct sock **sock_map;
struct bpf_prog *bpf_parse;
struct bpf_prog *bpf_verdict;
};
enum smap_psock_state {
SMAP_TX_RUNNING,
};
struct smap_psock_map_entry {
struct list_head list;
struct sock **entry;
};
struct smap_psock {
struct rcu_head rcu;
/* refcnt is used inside sk_callback_lock */
u32 refcnt;
/* datapath variables */
struct sk_buff_head rxqueue;
bool strp_enabled;
/* datapath error path cache across tx work invocations */
int save_rem;
int save_off;
struct sk_buff *save_skb;
struct strparser strp;
struct bpf_prog *bpf_parse;
struct bpf_prog *bpf_verdict;
struct list_head maps;
/* Back reference used when sock callback trigger sockmap operations */
struct sock *sock;
unsigned long state;
struct work_struct tx_work;
struct work_struct gc_work;
struct proto *sk_proto;
void (*save_close)(struct sock *sk, long timeout);
void (*save_data_ready)(struct sock *sk);
void (*save_write_space)(struct sock *sk);
};
static inline struct smap_psock *smap_psock_sk(const struct sock *sk)
{
return rcu_dereference_sk_user_data(sk);
}
static struct proto tcp_bpf_proto;
static int bpf_tcp_init(struct sock *sk)
{
struct smap_psock *psock;
rcu_read_lock();
psock = smap_psock_sk(sk);
if (unlikely(!psock)) {
rcu_read_unlock();
return -EINVAL;
}
if (unlikely(psock->sk_proto)) {
rcu_read_unlock();
return -EBUSY;
}
psock->save_close = sk->sk_prot->close;
psock->sk_proto = sk->sk_prot;
sk->sk_prot = &tcp_bpf_proto;
rcu_read_unlock();
return 0;
}
static void bpf_tcp_release(struct sock *sk)
{
struct smap_psock *psock;
rcu_read_lock();
psock = smap_psock_sk(sk);
if (likely(psock)) {
sk->sk_prot = psock->sk_proto;
psock->sk_proto = NULL;
}
rcu_read_unlock();
}
static void smap_release_sock(struct smap_psock *psock, struct sock *sock);
static void bpf_tcp_close(struct sock *sk, long timeout)
{
void (*close_fun)(struct sock *sk, long timeout);
struct smap_psock_map_entry *e, *tmp;
struct smap_psock *psock;
struct sock *osk;
rcu_read_lock();
psock = smap_psock_sk(sk);
if (unlikely(!psock)) {
rcu_read_unlock();
return sk->sk_prot->close(sk, timeout);
}
/* The psock may be destroyed anytime after exiting the RCU critial
* section so by the time we use close_fun the psock may no longer
* be valid. However, bpf_tcp_close is called with the sock lock
* held so the close hook and sk are still valid.
*/
close_fun = psock->save_close;
write_lock_bh(&sk->sk_callback_lock);
list_for_each_entry_safe(e, tmp, &psock->maps, list) {
osk = cmpxchg(e->entry, sk, NULL);
if (osk == sk) {
list_del(&e->list);
smap_release_sock(psock, sk);
}
}
write_unlock_bh(&sk->sk_callback_lock);
rcu_read_unlock();
close_fun(sk, timeout);
}
enum __sk_action {
__SK_DROP = 0,
__SK_PASS,
__SK_REDIRECT,
};
static struct tcp_ulp_ops bpf_tcp_ulp_ops __read_mostly = {
.name = "bpf_tcp",
.uid = TCP_ULP_BPF,
.user_visible = false,
.owner = NULL,
.init = bpf_tcp_init,
.release = bpf_tcp_release,
};
static int bpf_tcp_ulp_register(void)
{
tcp_bpf_proto = tcp_prot;
tcp_bpf_proto.close = bpf_tcp_close;
return tcp_register_ulp(&bpf_tcp_ulp_ops);
}
static int smap_verdict_func(struct smap_psock *psock, struct sk_buff *skb)
{
struct bpf_prog *prog = READ_ONCE(psock->bpf_verdict);
int rc;
if (unlikely(!prog))
return __SK_DROP;
skb_orphan(skb);
/* We need to ensure that BPF metadata for maps is also cleared
* when we orphan the skb so that we don't have the possibility
* to reference a stale map.
*/
TCP_SKB_CB(skb)->bpf.map = NULL;
skb->sk = psock->sock;
bpf_compute_data_pointers(skb);
preempt_disable();
rc = (*prog->bpf_func)(skb, prog->insnsi);
preempt_enable();
skb->sk = NULL;
/* Moving return codes from UAPI namespace into internal namespace */
return rc == SK_PASS ?
(TCP_SKB_CB(skb)->bpf.map ? __SK_REDIRECT : __SK_PASS) :
__SK_DROP;
}
static void smap_do_verdict(struct smap_psock *psock, struct sk_buff *skb)
{
struct sock *sk;
int rc;
rc = smap_verdict_func(psock, skb);
switch (rc) {
case __SK_REDIRECT:
sk = do_sk_redirect_map(skb);
if (likely(sk)) {
struct smap_psock *peer = smap_psock_sk(sk);
if (likely(peer &&
test_bit(SMAP_TX_RUNNING, &peer->state) &&
!sock_flag(sk, SOCK_DEAD) &&
sock_writeable(sk))) {
skb_set_owner_w(skb, sk);
skb_queue_tail(&peer->rxqueue, skb);
schedule_work(&peer->tx_work);
break;
}
}
/* Fall through and free skb otherwise */
case __SK_DROP:
default:
kfree_skb(skb);
}
}
static void smap_report_sk_error(struct smap_psock *psock, int err)
{
struct sock *sk = psock->sock;
sk->sk_err = err;
sk->sk_error_report(sk);
}
static void smap_read_sock_strparser(struct strparser *strp,
struct sk_buff *skb)
{
struct smap_psock *psock;
rcu_read_lock();
psock = container_of(strp, struct smap_psock, strp);
smap_do_verdict(psock, skb);
rcu_read_unlock();
}
/* Called with lock held on socket */
static void smap_data_ready(struct sock *sk)
{
struct smap_psock *psock;
rcu_read_lock();
psock = smap_psock_sk(sk);
if (likely(psock)) {
write_lock_bh(&sk->sk_callback_lock);
strp_data_ready(&psock->strp);
write_unlock_bh(&sk->sk_callback_lock);
}
rcu_read_unlock();
}
static void smap_tx_work(struct work_struct *w)
{
struct smap_psock *psock;
struct sk_buff *skb;
int rem, off, n;
psock = container_of(w, struct smap_psock, tx_work);
/* lock sock to avoid losing sk_socket at some point during loop */
lock_sock(psock->sock);
if (psock->save_skb) {
skb = psock->save_skb;
rem = psock->save_rem;
off = psock->save_off;
psock->save_skb = NULL;
goto start;
}
while ((skb = skb_dequeue(&psock->rxqueue))) {
rem = skb->len;
off = 0;
start:
do {
if (likely(psock->sock->sk_socket))
n = skb_send_sock_locked(psock->sock,
skb, off, rem);
else
n = -EINVAL;
if (n <= 0) {
if (n == -EAGAIN) {
/* Retry when space is available */
psock->save_skb = skb;
psock->save_rem = rem;
psock->save_off = off;
goto out;
}
/* Hard errors break pipe and stop xmit */
smap_report_sk_error(psock, n ? -n : EPIPE);
clear_bit(SMAP_TX_RUNNING, &psock->state);
kfree_skb(skb);
goto out;
}
rem -= n;
off += n;
} while (rem);
kfree_skb(skb);
}
out:
release_sock(psock->sock);
}
static void smap_write_space(struct sock *sk)
{
struct smap_psock *psock;
rcu_read_lock();
psock = smap_psock_sk(sk);
if (likely(psock && test_bit(SMAP_TX_RUNNING, &psock->state)))
schedule_work(&psock->tx_work);
rcu_read_unlock();
}
static void smap_stop_sock(struct smap_psock *psock, struct sock *sk)
{
if (!psock->strp_enabled)
return;
sk->sk_data_ready = psock->save_data_ready;
sk->sk_write_space = psock->save_write_space;
psock->save_data_ready = NULL;
psock->save_write_space = NULL;
strp_stop(&psock->strp);
psock->strp_enabled = false;
}
static void smap_destroy_psock(struct rcu_head *rcu)
{
struct smap_psock *psock = container_of(rcu,
struct smap_psock, rcu);
/* Now that a grace period has passed there is no longer
* any reference to this sock in the sockmap so we can
* destroy the psock, strparser, and bpf programs. But,
* because we use workqueue sync operations we can not
* do it in rcu context
*/
schedule_work(&psock->gc_work);
}
static void smap_release_sock(struct smap_psock *psock, struct sock *sock)
{
psock->refcnt--;
if (psock->refcnt)
return;
tcp_cleanup_ulp(sock);
smap_stop_sock(psock, sock);
clear_bit(SMAP_TX_RUNNING, &psock->state);
rcu_assign_sk_user_data(sock, NULL);
call_rcu_sched(&psock->rcu, smap_destroy_psock);
}
static int smap_parse_func_strparser(struct strparser *strp,
struct sk_buff *skb)
{
struct smap_psock *psock;
struct bpf_prog *prog;
int rc;
rcu_read_lock();
psock = container_of(strp, struct smap_psock, strp);
prog = READ_ONCE(psock->bpf_parse);
if (unlikely(!prog)) {
rcu_read_unlock();
return skb->len;
}
/* Attach socket for bpf program to use if needed we can do this
* because strparser clones the skb before handing it to a upper
* layer, meaning skb_orphan has been called. We NULL sk on the
* way out to ensure we don't trigger a BUG_ON in skb/sk operations
* later and because we are not charging the memory of this skb to
* any socket yet.
*/
skb->sk = psock->sock;
bpf_compute_data_pointers(skb);
rc = (*prog->bpf_func)(skb, prog->insnsi);
skb->sk = NULL;
rcu_read_unlock();
return rc;
}
static int smap_read_sock_done(struct strparser *strp, int err)
{
return err;
}
static int smap_init_sock(struct smap_psock *psock,
struct sock *sk)
{
static const struct strp_callbacks cb = {
.rcv_msg = smap_read_sock_strparser,
.parse_msg = smap_parse_func_strparser,
.read_sock_done = smap_read_sock_done,
};
return strp_init(&psock->strp, sk, &cb);
}
static void smap_init_progs(struct smap_psock *psock,
struct bpf_stab *stab,
struct bpf_prog *verdict,
struct bpf_prog *parse)
{
struct bpf_prog *orig_parse, *orig_verdict;
orig_parse = xchg(&psock->bpf_parse, parse);
orig_verdict = xchg(&psock->bpf_verdict, verdict);
if (orig_verdict)
bpf_prog_put(orig_verdict);
if (orig_parse)
bpf_prog_put(orig_parse);
}
static void smap_start_sock(struct smap_psock *psock, struct sock *sk)
{
if (sk->sk_data_ready == smap_data_ready)
return;
psock->save_data_ready = sk->sk_data_ready;
psock->save_write_space = sk->sk_write_space;
sk->sk_data_ready = smap_data_ready;
sk->sk_write_space = smap_write_space;
psock->strp_enabled = true;
}
static void sock_map_remove_complete(struct bpf_stab *stab)
{
bpf_map_area_free(stab->sock_map);
kfree(stab);
}
static void smap_gc_work(struct work_struct *w)
{
struct smap_psock_map_entry *e, *tmp;
struct smap_psock *psock;
psock = container_of(w, struct smap_psock, gc_work);
/* no callback lock needed because we already detached sockmap ops */
if (psock->strp_enabled)
strp_done(&psock->strp);
cancel_work_sync(&psock->tx_work);
__skb_queue_purge(&psock->rxqueue);
/* At this point all strparser and xmit work must be complete */
if (psock->bpf_parse)
bpf_prog_put(psock->bpf_parse);
if (psock->bpf_verdict)
bpf_prog_put(psock->bpf_verdict);
list_for_each_entry_safe(e, tmp, &psock->maps, list) {
list_del(&e->list);
kfree(e);
}
sock_put(psock->sock);
kfree(psock);
}
static struct smap_psock *smap_init_psock(struct sock *sock,
struct bpf_stab *stab)
{
struct smap_psock *psock;
psock = kzalloc_node(sizeof(struct smap_psock),
GFP_ATOMIC | __GFP_NOWARN,
stab->map.numa_node);
if (!psock)
return ERR_PTR(-ENOMEM);
psock->sock = sock;
skb_queue_head_init(&psock->rxqueue);
INIT_WORK(&psock->tx_work, smap_tx_work);
INIT_WORK(&psock->gc_work, smap_gc_work);
INIT_LIST_HEAD(&psock->maps);
psock->refcnt = 1;
rcu_assign_sk_user_data(sock, psock);
sock_hold(sock);
return psock;
}
static struct bpf_map *sock_map_alloc(union bpf_attr *attr)
{
struct bpf_stab *stab;
u64 cost;
int err;
if (!capable(CAP_NET_ADMIN))
return ERR_PTR(-EPERM);
/* check sanity of attributes */
if (attr->max_entries == 0 || attr->key_size != 4 ||
attr->value_size != 4 || attr->map_flags & ~SOCK_CREATE_FLAG_MASK)
return ERR_PTR(-EINVAL);
if (attr->value_size > KMALLOC_MAX_SIZE)
return ERR_PTR(-E2BIG);
err = bpf_tcp_ulp_register();
if (err && err != -EEXIST)
return ERR_PTR(err);
stab = kzalloc(sizeof(*stab), GFP_USER);
if (!stab)
return ERR_PTR(-ENOMEM);
bpf_map_init_from_attr(&stab->map, attr);
/* make sure page count doesn't overflow */
cost = (u64) stab->map.max_entries * sizeof(struct sock *);
err = -EINVAL;
if (cost >= U32_MAX - PAGE_SIZE)
goto free_stab;
stab->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;
/* if map size is larger than memlock limit, reject it early */
err = bpf_map_precharge_memlock(stab->map.pages);
if (err)
goto free_stab;
err = -ENOMEM;
stab->sock_map = bpf_map_area_alloc(stab->map.max_entries *
sizeof(struct sock *),
stab->map.numa_node);
if (!stab->sock_map)
goto free_stab;
return &stab->map;
free_stab:
kfree(stab);
return ERR_PTR(err);
}
static void smap_list_remove(struct smap_psock *psock, struct sock **entry)
{
struct smap_psock_map_entry *e, *tmp;
list_for_each_entry_safe(e, tmp, &psock->maps, list) {
if (e->entry == entry) {
list_del(&e->list);
break;
}
}
}
static void sock_map_free(struct bpf_map *map)
{
struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
int i;
synchronize_rcu();
/* At this point no update, lookup or delete operations can happen.
* However, be aware we can still get a socket state event updates,
* and data ready callabacks that reference the psock from sk_user_data
* Also psock worker threads are still in-flight. So smap_release_sock
* will only free the psock after cancel_sync on the worker threads
* and a grace period expire to ensure psock is really safe to remove.
*/
rcu_read_lock();
for (i = 0; i < stab->map.max_entries; i++) {
struct smap_psock *psock;
struct sock *sock;
sock = xchg(&stab->sock_map[i], NULL);
if (!sock)
continue;
write_lock_bh(&sock->sk_callback_lock);
psock = smap_psock_sk(sock);
/* This check handles a racing sock event that can get the
* sk_callback_lock before this case but after xchg happens
* causing the refcnt to hit zero and sock user data (psock)
* to be null and queued for garbage collection.
*/
if (likely(psock)) {
smap_list_remove(psock, &stab->sock_map[i]);
smap_release_sock(psock, sock);
}
write_unlock_bh(&sock->sk_callback_lock);
}
rcu_read_unlock();
sock_map_remove_complete(stab);
}
static int sock_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
{
struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
u32 i = key ? *(u32 *)key : U32_MAX;
u32 *next = (u32 *)next_key;
if (i >= stab->map.max_entries) {
*next = 0;
return 0;
}
if (i == stab->map.max_entries - 1)
return -ENOENT;
*next = i + 1;
return 0;
}
struct sock *__sock_map_lookup_elem(struct bpf_map *map, u32 key)
{
struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
if (key >= map->max_entries)
return NULL;
return READ_ONCE(stab->sock_map[key]);
}
static int sock_map_delete_elem(struct bpf_map *map, void *key)
{
struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
struct smap_psock *psock;
int k = *(u32 *)key;
struct sock *sock;
if (k >= map->max_entries)
return -EINVAL;
sock = xchg(&stab->sock_map[k], NULL);
if (!sock)
return -EINVAL;
write_lock_bh(&sock->sk_callback_lock);
psock = smap_psock_sk(sock);
if (!psock)
goto out;
if (psock->bpf_parse)
smap_stop_sock(psock, sock);
smap_list_remove(psock, &stab->sock_map[k]);
smap_release_sock(psock, sock);
out:
write_unlock_bh(&sock->sk_callback_lock);
return 0;
}
/* Locking notes: Concurrent updates, deletes, and lookups are allowed and are
* done inside rcu critical sections. This ensures on updates that the psock
* will not be released via smap_release_sock() until concurrent updates/deletes
* complete. All operations operate on sock_map using cmpxchg and xchg
* operations to ensure we do not get stale references. Any reads into the
* map must be done with READ_ONCE() because of this.
*
* A psock is destroyed via call_rcu and after any worker threads are cancelled
* and syncd so we are certain all references from the update/lookup/delete
* operations as well as references in the data path are no longer in use.
*
* Psocks may exist in multiple maps, but only a single set of parse/verdict
* programs may be inherited from the maps it belongs to. A reference count
* is kept with the total number of references to the psock from all maps. The
* psock will not be released until this reaches zero. The psock and sock
* user data data use the sk_callback_lock to protect critical data structures
* from concurrent access. This allows us to avoid two updates from modifying
* the user data in sock and the lock is required anyways for modifying
* callbacks, we simply increase its scope slightly.
*
* Rules to follow,
* - psock must always be read inside RCU critical section
* - sk_user_data must only be modified inside sk_callback_lock and read
* inside RCU critical section.
* - psock->maps list must only be read & modified inside sk_callback_lock
* - sock_map must use READ_ONCE and (cmp)xchg operations
* - BPF verdict/parse programs must use READ_ONCE and xchg operations
*/
static int sock_map_ctx_update_elem(struct bpf_sock_ops_kern *skops,
struct bpf_map *map,
void *key, u64 flags)
{
struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
struct smap_psock_map_entry *e = NULL;
struct bpf_prog *verdict, *parse;
struct sock *osock, *sock;
struct smap_psock *psock;
u32 i = *(u32 *)key;
int err;
if (unlikely(flags > BPF_EXIST))
return -EINVAL;
if (unlikely(i >= stab->map.max_entries))
return -E2BIG;
sock = READ_ONCE(stab->sock_map[i]);
if (flags == BPF_EXIST && !sock)
return -ENOENT;
else if (flags == BPF_NOEXIST && sock)
return -EEXIST;
sock = skops->sk;
/* 1. If sock map has BPF programs those will be inherited by the
* sock being added. If the sock is already attached to BPF programs
* this results in an error.
*/
verdict = READ_ONCE(stab->bpf_verdict);
parse = READ_ONCE(stab->bpf_parse);
if (parse && verdict) {
/* bpf prog refcnt may be zero if a concurrent attach operation
* removes the program after the above READ_ONCE() but before
* we increment the refcnt. If this is the case abort with an
* error.
*/
verdict = bpf_prog_inc_not_zero(stab->bpf_verdict);
if (IS_ERR(verdict))
return PTR_ERR(verdict);
parse = bpf_prog_inc_not_zero(stab->bpf_parse);
if (IS_ERR(parse)) {
bpf_prog_put(verdict);
return PTR_ERR(parse);
}
}
write_lock_bh(&sock->sk_callback_lock);
psock = smap_psock_sk(sock);
/* 2. Do not allow inheriting programs if psock exists and has
* already inherited programs. This would create confusion on
* which parser/verdict program is running. If no psock exists
* create one. Inside sk_callback_lock to ensure concurrent create
* doesn't update user data.
*/
if (psock) {
if (READ_ONCE(psock->bpf_parse) && parse) {
err = -EBUSY;
goto out_progs;
}
psock->refcnt++;
} else {
psock = smap_init_psock(sock, stab);
if (IS_ERR(psock)) {
err = PTR_ERR(psock);
goto out_progs;
}
err = tcp_set_ulp_id(sock, TCP_ULP_BPF);
if (err)
goto out_progs;
set_bit(SMAP_TX_RUNNING, &psock->state);
}
e = kzalloc(sizeof(*e), GFP_ATOMIC | __GFP_NOWARN);
if (!e) {
err = -ENOMEM;
goto out_progs;
}
e->entry = &stab->sock_map[i];
/* 3. At this point we have a reference to a valid psock that is
* running. Attach any BPF programs needed.
*/
if (parse && verdict && !psock->strp_enabled) {
err = smap_init_sock(psock, sock);
if (err)
goto out_free;
smap_init_progs(psock, stab, verdict, parse);
smap_start_sock(psock, sock);
}
/* 4. Place psock in sockmap for use and stop any programs on
* the old sock assuming its not the same sock we are replacing
* it with. Because we can only have a single set of programs if
* old_sock has a strp we can stop it.
*/
list_add_tail(&e->list, &psock->maps);
write_unlock_bh(&sock->sk_callback_lock);
osock = xchg(&stab->sock_map[i], sock);
if (osock) {
struct smap_psock *opsock = smap_psock_sk(osock);
write_lock_bh(&osock->sk_callback_lock);
if (osock != sock && parse)
smap_stop_sock(opsock, osock);
smap_list_remove(opsock, &stab->sock_map[i]);
smap_release_sock(opsock, osock);
write_unlock_bh(&osock->sk_callback_lock);
}
return 0;
out_free:
smap_release_sock(psock, sock);
out_progs:
if (verdict)
bpf_prog_put(verdict);
if (parse)
bpf_prog_put(parse);
write_unlock_bh(&sock->sk_callback_lock);
kfree(e);
return err;
}
int sock_map_prog(struct bpf_map *map, struct bpf_prog *prog, u32 type)
{
struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
struct bpf_prog *orig;
if (unlikely(map->map_type != BPF_MAP_TYPE_SOCKMAP))
return -EINVAL;
switch (type) {
case BPF_SK_SKB_STREAM_PARSER:
orig = xchg(&stab->bpf_parse, prog);
break;
case BPF_SK_SKB_STREAM_VERDICT:
orig = xchg(&stab->bpf_verdict, prog);
break;
default:
return -EOPNOTSUPP;
}
if (orig)
bpf_prog_put(orig);
return 0;
}
static void *sock_map_lookup(struct bpf_map *map, void *key)
{
return NULL;
}
static int sock_map_update_elem(struct bpf_map *map,
void *key, void *value, u64 flags)
{
struct bpf_sock_ops_kern skops;
u32 fd = *(u32 *)value;
struct socket *socket;
int err;
socket = sockfd_lookup(fd, &err);
if (!socket)
return err;
skops.sk = socket->sk;
if (!skops.sk) {
fput(socket->file);
return -EINVAL;
}
if (skops.sk->sk_type != SOCK_STREAM ||
skops.sk->sk_protocol != IPPROTO_TCP) {
fput(socket->file);
return -EOPNOTSUPP;
}
err = sock_map_ctx_update_elem(&skops, map, key, flags);
fput(socket->file);
return err;
}
static void sock_map_release(struct bpf_map *map, struct file *map_file)
{
struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
struct bpf_prog *orig;
orig = xchg(&stab->bpf_parse, NULL);
if (orig)
bpf_prog_put(orig);
orig = xchg(&stab->bpf_verdict, NULL);
if (orig)
bpf_prog_put(orig);
}
const struct bpf_map_ops sock_map_ops = {
.map_alloc = sock_map_alloc,
.map_free = sock_map_free,
.map_lookup_elem = sock_map_lookup,
.map_get_next_key = sock_map_get_next_key,
.map_update_elem = sock_map_update_elem,
.map_delete_elem = sock_map_delete_elem,
.map_release = sock_map_release,
};
BPF_CALL_4(bpf_sock_map_update, struct bpf_sock_ops_kern *, bpf_sock,
struct bpf_map *, map, void *, key, u64, flags)
{
WARN_ON_ONCE(!rcu_read_lock_held());
return sock_map_ctx_update_elem(bpf_sock, map, key, flags);
}
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,
};