// SPDX-License-Identifier: GPL-2.0-only
/*
* Kernel Connection Multiplexor
*
* Copyright (c) 2016 Tom Herbert <[email protected]>
*/
#include <linux/bpf.h>
#include <linux/errno.h>
#include <linux/errqueue.h>
#include <linux/file.h>
#include <linux/filter.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/poll.h>
#include <linux/rculist.h>
#include <linux/skbuff.h>
#include <linux/socket.h>
#include <linux/uaccess.h>
#include <linux/workqueue.h>
#include <linux/syscalls.h>
#include <linux/sched/signal.h>
#include <net/kcm.h>
#include <net/netns/generic.h>
#include <net/sock.h>
#include <uapi/linux/kcm.h>
#include <trace/events/sock.h>
unsigned int kcm_net_id;
static struct kmem_cache *kcm_psockp __read_mostly;
static struct kmem_cache *kcm_muxp __read_mostly;
static struct workqueue_struct *kcm_wq;
static inline struct kcm_sock *kcm_sk(const struct sock *sk)
{
return (struct kcm_sock *)sk;
}
static inline struct kcm_tx_msg *kcm_tx_msg(struct sk_buff *skb)
{
return (struct kcm_tx_msg *)skb->cb;
}
static void report_csk_error(struct sock *csk, int err)
{
csk->sk_err = EPIPE;
sk_error_report(csk);
}
static void kcm_abort_tx_psock(struct kcm_psock *psock, int err,
bool wakeup_kcm)
{
struct sock *csk = psock->sk;
struct kcm_mux *mux = psock->mux;
/* Unrecoverable error in transmit */
spin_lock_bh(&mux->lock);
if (psock->tx_stopped) {
spin_unlock_bh(&mux->lock);
return;
}
psock->tx_stopped = 1;
KCM_STATS_INCR(psock->stats.tx_aborts);
if (!psock->tx_kcm) {
/* Take off psocks_avail list */
list_del(&psock->psock_avail_list);
} else if (wakeup_kcm) {
/* In this case psock is being aborted while outside of
* write_msgs and psock is reserved. Schedule tx_work
* to handle the failure there. Need to commit tx_stopped
* before queuing work.
*/
smp_mb();
queue_work(kcm_wq, &psock->tx_kcm->tx_work);
}
spin_unlock_bh(&mux->lock);
/* Report error on lower socket */
report_csk_error(csk, err);
}
/* RX mux lock held. */
static void kcm_update_rx_mux_stats(struct kcm_mux *mux,
struct kcm_psock *psock)
{
STRP_STATS_ADD(mux->stats.rx_bytes,
psock->strp.stats.bytes -
psock->saved_rx_bytes);
mux->stats.rx_msgs +=
psock->strp.stats.msgs - psock->saved_rx_msgs;
psock->saved_rx_msgs = psock->strp.stats.msgs;
psock->saved_rx_bytes = psock->strp.stats.bytes;
}
static void kcm_update_tx_mux_stats(struct kcm_mux *mux,
struct kcm_psock *psock)
{
KCM_STATS_ADD(mux->stats.tx_bytes,
psock->stats.tx_bytes - psock->saved_tx_bytes);
mux->stats.tx_msgs +=
psock->stats.tx_msgs - psock->saved_tx_msgs;
psock->saved_tx_msgs = psock->stats.tx_msgs;
psock->saved_tx_bytes = psock->stats.tx_bytes;
}
static int kcm_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
/* KCM is ready to receive messages on its queue-- either the KCM is new or
* has become unblocked after being blocked on full socket buffer. Queue any
* pending ready messages on a psock. RX mux lock held.
*/
static void kcm_rcv_ready(struct kcm_sock *kcm)
{
struct kcm_mux *mux = kcm->mux;
struct kcm_psock *psock;
struct sk_buff *skb;
if (unlikely(kcm->rx_wait || kcm->rx_psock || kcm->rx_disabled))
return;
while (unlikely((skb = __skb_dequeue(&mux->rx_hold_queue)))) {
if (kcm_queue_rcv_skb(&kcm->sk, skb)) {
/* Assuming buffer limit has been reached */
skb_queue_head(&mux->rx_hold_queue, skb);
WARN_ON(!sk_rmem_alloc_get(&kcm->sk));
return;
}
}
while (!list_empty(&mux->psocks_ready)) {
psock = list_first_entry(&mux->psocks_ready, struct kcm_psock,
psock_ready_list);
if (kcm_queue_rcv_skb(&kcm->sk, psock->ready_rx_msg)) {
/* Assuming buffer limit has been reached */
WARN_ON(!sk_rmem_alloc_get(&kcm->sk));
return;
}
/* Consumed the ready message on the psock. Schedule rx_work to
* get more messages.
*/
list_del(&psock->psock_ready_list);
psock->ready_rx_msg = NULL;
/* Commit clearing of ready_rx_msg for queuing work */
smp_mb();
strp_unpause(&psock->strp);
strp_check_rcv(&psock->strp);
}
/* Buffer limit is okay now, add to ready list */
list_add_tail(&kcm->wait_rx_list,
&kcm->mux->kcm_rx_waiters);
/* paired with lockless reads in kcm_rfree() */
WRITE_ONCE(kcm->rx_wait, true);
}
static void kcm_rfree(struct sk_buff *skb)
{
struct sock *sk = skb->sk;
struct kcm_sock *kcm = kcm_sk(sk);
struct kcm_mux *mux = kcm->mux;
unsigned int len = skb->truesize;
sk_mem_uncharge(sk, len);
atomic_sub(len, &sk->sk_rmem_alloc);
/* For reading rx_wait and rx_psock without holding lock */
smp_mb__after_atomic();
if (!READ_ONCE(kcm->rx_wait) && !READ_ONCE(kcm->rx_psock) &&
sk_rmem_alloc_get(sk) < sk->sk_rcvlowat) {
spin_lock_bh(&mux->rx_lock);
kcm_rcv_ready(kcm);
spin_unlock_bh(&mux->rx_lock);
}
}
static int kcm_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
struct sk_buff_head *list = &sk->sk_receive_queue;
if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
return -ENOMEM;
if (!sk_rmem_schedule(sk, skb, skb->truesize))
return -ENOBUFS;
skb->dev = NULL;
skb_orphan(skb);
skb->sk = sk;
skb->destructor = kcm_rfree;
atomic_add(skb->truesize, &sk->sk_rmem_alloc);
sk_mem_charge(sk, skb->truesize);
skb_queue_tail(list, skb);
if (!sock_flag(sk, SOCK_DEAD))
sk->sk_data_ready(sk);
return 0;
}
/* Requeue received messages for a kcm socket to other kcm sockets. This is
* called with a kcm socket is receive disabled.
* RX mux lock held.
*/
static void requeue_rx_msgs(struct kcm_mux *mux, struct sk_buff_head *head)
{
struct sk_buff *skb;
struct kcm_sock *kcm;
while ((skb = skb_dequeue(head))) {
/* Reset destructor to avoid calling kcm_rcv_ready */
skb->destructor = sock_rfree;
skb_orphan(skb);
try_again:
if (list_empty(&mux->kcm_rx_waiters)) {
skb_queue_tail(&mux->rx_hold_queue, skb);
continue;
}
kcm = list_first_entry(&mux->kcm_rx_waiters,
struct kcm_sock, wait_rx_list);
if (kcm_queue_rcv_skb(&kcm->sk, skb)) {
/* Should mean socket buffer full */
list_del(&kcm->wait_rx_list);
/* paired with lockless reads in kcm_rfree() */
WRITE_ONCE(kcm->rx_wait, false);
/* Commit rx_wait to read in kcm_free */
smp_wmb();
goto try_again;
}
}
}
/* Lower sock lock held */
static struct kcm_sock *reserve_rx_kcm(struct kcm_psock *psock,
struct sk_buff *head)
{
struct kcm_mux *mux = psock->mux;
struct kcm_sock *kcm;
WARN_ON(psock->ready_rx_msg);
if (psock->rx_kcm)
return psock->rx_kcm;
spin_lock_bh(&mux->rx_lock);
if (psock->rx_kcm) {
spin_unlock_bh(&mux->rx_lock);
return psock->rx_kcm;
}
kcm_update_rx_mux_stats(mux, psock);
if (list_empty(&mux->kcm_rx_waiters)) {
psock->ready_rx_msg = head;
strp_pause(&psock->strp);
list_add_tail(&psock->psock_ready_list,
&mux->psocks_ready);
spin_unlock_bh(&mux->rx_lock);
return NULL;
}
kcm = list_first_entry(&mux->kcm_rx_waiters,
struct kcm_sock, wait_rx_list);
list_del(&kcm->wait_rx_list);
/* paired with lockless reads in kcm_rfree() */
WRITE_ONCE(kcm->rx_wait, false);
psock->rx_kcm = kcm;
/* paired with lockless reads in kcm_rfree() */
WRITE_ONCE(kcm->rx_psock, psock);
spin_unlock_bh(&mux->rx_lock);
return kcm;
}
static void kcm_done(struct kcm_sock *kcm);
static void kcm_done_work(struct work_struct *w)
{
kcm_done(container_of(w, struct kcm_sock, done_work));
}
/* Lower sock held */
static void unreserve_rx_kcm(struct kcm_psock *psock,
bool rcv_ready)
{
struct kcm_sock *kcm = psock->rx_kcm;
struct kcm_mux *mux = psock->mux;
if (!kcm)
return;
spin_lock_bh(&mux->rx_lock);
psock->rx_kcm = NULL;
/* paired with lockless reads in kcm_rfree() */
WRITE_ONCE(kcm->rx_psock, NULL);
/* Commit kcm->rx_psock before sk_rmem_alloc_get to sync with
* kcm_rfree
*/
smp_mb();
if (unlikely(kcm->done)) {
spin_unlock_bh(&mux->rx_lock);
/* Need to run kcm_done in a task since we need to qcquire
* callback locks which may already be held here.
*/
INIT_WORK(&kcm->done_work, kcm_done_work);
schedule_work(&kcm->done_work);
return;
}
if (unlikely(kcm->rx_disabled)) {
requeue_rx_msgs(mux, &kcm->sk.sk_receive_queue);
} else if (rcv_ready || unlikely(!sk_rmem_alloc_get(&kcm->sk))) {
/* Check for degenerative race with rx_wait that all
* data was dequeued (accounted for in kcm_rfree).
*/
kcm_rcv_ready(kcm);
}
spin_unlock_bh(&mux->rx_lock);
}
/* Lower sock lock held */
static void psock_data_ready(struct sock *sk)
{
struct kcm_psock *psock;
trace_sk_data_ready(sk);
read_lock_bh(&sk->sk_callback_lock);
psock = (struct kcm_psock *)sk->sk_user_data;
if (likely(psock))
strp_data_ready(&psock->strp);
read_unlock_bh(&sk->sk_callback_lock);
}
/* Called with lower sock held */
static void kcm_rcv_strparser(struct strparser *strp, struct sk_buff *skb)
{
struct kcm_psock *psock = container_of(strp, struct kcm_psock, strp);
struct kcm_sock *kcm;
try_queue:
kcm = reserve_rx_kcm(psock, skb);
if (!kcm) {
/* Unable to reserve a KCM, message is held in psock and strp
* is paused.
*/
return;
}
if (kcm_queue_rcv_skb(&kcm->sk, skb)) {
/* Should mean socket buffer full */
unreserve_rx_kcm(psock, false);
goto try_queue;
}
}
static int kcm_parse_func_strparser(struct strparser *strp, struct sk_buff *skb)
{
struct kcm_psock *psock = container_of(strp, struct kcm_psock, strp);
struct bpf_prog *prog = psock->bpf_prog;
int res;
res = bpf_prog_run_pin_on_cpu(prog, skb);
return res;
}
static int kcm_read_sock_done(struct strparser *strp, int err)
{
struct kcm_psock *psock = container_of(strp, struct kcm_psock, strp);
unreserve_rx_kcm(psock, true);
return err;
}
static void psock_state_change(struct sock *sk)
{
/* TCP only does a EPOLLIN for a half close. Do a EPOLLHUP here
* since application will normally not poll with EPOLLIN
* on the TCP sockets.
*/
report_csk_error(sk, EPIPE);
}
static void psock_write_space(struct sock *sk)
{
struct kcm_psock *psock;
struct kcm_mux *mux;
struct kcm_sock *kcm;
read_lock_bh(&sk->sk_callback_lock);
psock = (struct kcm_psock *)sk->sk_user_data;
if (unlikely(!psock))
goto out;
mux = psock->mux;
spin_lock_bh(&mux->lock);
/* Check if the socket is reserved so someone is waiting for sending. */
kcm = psock->tx_kcm;
if (kcm && !unlikely(kcm->tx_stopped))
queue_work(kcm_wq, &kcm->tx_work);
spin_unlock_bh(&mux->lock);
out:
read_unlock_bh(&sk->sk_callback_lock);
}
static void unreserve_psock(struct kcm_sock *kcm);
/* kcm sock is locked. */
static struct kcm_psock *reserve_psock(struct kcm_sock *kcm)
{
struct kcm_mux *mux = kcm->mux;
struct kcm_psock *psock;
psock = kcm->tx_psock;
smp_rmb(); /* Must read tx_psock before tx_wait */
if (psock) {
WARN_ON(kcm->tx_wait);
if (unlikely(psock->tx_stopped))
unreserve_psock(kcm);
else
return kcm->tx_psock;
}
spin_lock_bh(&mux->lock);
/* Check again under lock to see if psock was reserved for this
* psock via psock_unreserve.
*/
psock = kcm->tx_psock;
if (unlikely(psock)) {
WARN_ON(kcm->tx_wait);
spin_unlock_bh(&mux->lock);
return kcm->tx_psock;
}
if (!list_empty(&mux->psocks_avail)) {
psock = list_first_entry(&mux->psocks_avail,
struct kcm_psock,
psock_avail_list);
list_del(&psock->psock_avail_list);
if (kcm->tx_wait) {
list_del(&kcm->wait_psock_list);
kcm->tx_wait = false;
}
kcm->tx_psock = psock;
psock->tx_kcm = kcm;
KCM_STATS_INCR(psock->stats.reserved);
} else if (!kcm->tx_wait) {
list_add_tail(&kcm->wait_psock_list,
&mux->kcm_tx_waiters);
kcm->tx_wait = true;
}
spin_unlock_bh(&mux->lock);
return psock;
}
/* mux lock held */
static void psock_now_avail(struct kcm_psock *psock)
{
struct kcm_mux *mux = psock->mux;
struct kcm_sock *kcm;
if (list_empty(&mux->kcm_tx_waiters)) {
list_add_tail(&psock->psock_avail_list,
&mux->psocks_avail);
} else {
kcm = list_first_entry(&mux->kcm_tx_waiters,
struct kcm_sock,
wait_psock_list);
list_del(&kcm->wait_psock_list);
kcm->tx_wait = false;
psock->tx_kcm = kcm;
/* Commit before changing tx_psock since that is read in
* reserve_psock before queuing work.
*/
smp_mb();
kcm->tx_psock = psock;
KCM_STATS_INCR(psock->stats.reserved);
queue_work(kcm_wq, &kcm->tx_work);
}
}
/* kcm sock is locked. */
static void unreserve_psock(struct kcm_sock *kcm)
{
struct kcm_psock *psock;
struct kcm_mux *mux = kcm->mux;
spin_lock_bh(&mux->lock);
psock = kcm->tx_psock;
if (WARN_ON(!psock)) {
spin_unlock_bh(&mux->lock);
return;
}
smp_rmb(); /* Read tx_psock before tx_wait */
kcm_update_tx_mux_stats(mux, psock);
WARN_ON(kcm->tx_wait);
kcm->tx_psock = NULL;
psock->tx_kcm = NULL;
KCM_STATS_INCR(psock->stats.unreserved);
if (unlikely(psock->tx_stopped)) {
if (psock->done) {
/* Deferred free */
list_del(&psock->psock_list);
mux->psocks_cnt--;
sock_put(psock->sk);
fput(psock->sk->sk_socket->file);
kmem_cache_free(kcm_psockp, psock);
}
/* Don't put back on available list */
spin_unlock_bh(&mux->lock);
return;
}
psock_now_avail(psock);
spin_unlock_bh(&mux->lock);
}
static void kcm_report_tx_retry(struct kcm_sock *kcm)
{
struct kcm_mux *mux = kcm->mux;
spin_lock_bh(&mux->lock);
KCM_STATS_INCR(mux->stats.tx_retries);
spin_unlock_bh(&mux->lock);
}
/* Write any messages ready on the kcm socket. Called with kcm sock lock
* held. Return bytes actually sent or error.
*/
static int kcm_write_msgs(struct kcm_sock *kcm)
{
unsigned int total_sent = 0;
struct sock *sk = &kcm->sk;
struct kcm_psock *psock;
struct sk_buff *head;
int ret = 0;
kcm->tx_wait_more = false;
psock = kcm->tx_psock;
if (unlikely(psock && psock->tx_stopped)) {
/* A reserved psock was aborted asynchronously. Unreserve
* it and we'll retry the message.
*/
unreserve_psock(kcm);
kcm_report_tx_retry(kcm);
if (skb_queue_empty(&sk->sk_write_queue))
return 0;
kcm_tx_msg(skb_peek(&sk->sk_write_queue))->started_tx = false;
}
retry:
while ((head = skb_peek(&sk->sk_write_queue))) {
struct msghdr msg = {
.msg_flags = MSG_DONTWAIT | MSG_SPLICE_PAGES,
};
struct kcm_tx_msg *txm = kcm_tx_msg(head);
struct sk_buff *skb;
unsigned int msize;
int i;
if (!txm->started_tx) {
psock = reserve_psock(kcm);
if (!psock)
goto out;
skb = head;
txm->frag_offset = 0;
txm->sent = 0;
txm->started_tx = true;
} else {
if (WARN_ON(!psock)) {
ret = -EINVAL;
goto out;
}
skb = txm->frag_skb;
}
if (WARN_ON(!skb_shinfo(skb)->nr_frags) ||
WARN_ON_ONCE(!skb_frag_page(&skb_shinfo(skb)->frags[0]))) {
ret = -EINVAL;
goto out;
}
msize = 0;
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
msize += skb_frag_size(&skb_shinfo(skb)->frags[i]);
iov_iter_bvec(&msg.msg_iter, ITER_SOURCE,
(const struct bio_vec *)skb_shinfo(skb)->frags,
skb_shinfo(skb)->nr_frags, msize);
iov_iter_advance(&msg.msg_iter, txm->frag_offset);
do {
ret = sock_sendmsg(psock->sk->sk_socket, &msg);
if (ret <= 0) {
if (ret == -EAGAIN) {
/* Save state to try again when there's
* write space on the socket
*/
txm->frag_skb = skb;
ret = 0;
goto out;
}
/* Hard failure in sending message, abort this
* psock since it has lost framing
* synchronization and retry sending the
* message from the beginning.
*/
kcm_abort_tx_psock(psock, ret ? -ret : EPIPE,
true);
unreserve_psock(kcm);
psock = NULL;
txm->started_tx = false;
kcm_report_tx_retry(kcm);
ret = 0;
goto retry;
}
txm->sent += ret;
txm->frag_offset += ret;
KCM_STATS_ADD(psock->stats.tx_bytes, ret);
} while (msg.msg_iter.count > 0);
if (skb == head) {
if (skb_has_frag_list(skb)) {
txm->frag_skb = skb_shinfo(skb)->frag_list;
txm->frag_offset = 0;
continue;
}
} else if (skb->next) {
txm->frag_skb = skb->next;
txm->frag_offset = 0;
continue;
}
/* Successfully sent the whole packet, account for it. */
sk->sk_wmem_queued -= txm->sent;
total_sent += txm->sent;
skb_dequeue(&sk->sk_write_queue);
kfree_skb(head);
KCM_STATS_INCR(psock->stats.tx_msgs);
}
out:
if (!head) {
/* Done with all queued messages. */
WARN_ON(!skb_queue_empty(&sk->sk_write_queue));
if (psock)
unreserve_psock(kcm);
}
/* Check if write space is available */
sk->sk_write_space(sk);
return total_sent ? : ret;
}
static void kcm_tx_work(struct work_struct *w)
{
struct kcm_sock *kcm = container_of(w, struct kcm_sock, tx_work);
struct sock *sk = &kcm->sk;
int err;
lock_sock(sk);
/* Primarily for SOCK_DGRAM sockets, also handle asynchronous tx
* aborts
*/
err = kcm_write_msgs(kcm);
if (err < 0) {
/* Hard failure in write, report error on KCM socket */
pr_warn("KCM: Hard failure on kcm_write_msgs %d\n", err);
report_csk_error(&kcm->sk, -err);
goto out;
}
/* Primarily for SOCK_SEQPACKET sockets */
if (likely(sk->sk_socket) &&
test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
clear_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
sk->sk_write_space(sk);
}
out:
release_sock(sk);
}
static void kcm_push(struct kcm_sock *kcm)
{
if (kcm->tx_wait_more)
kcm_write_msgs(kcm);
}
static int kcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
{
struct sock *sk = sock->sk;
struct kcm_sock *kcm = kcm_sk(sk);
struct sk_buff *skb = NULL, *head = NULL;
size_t copy, copied = 0;
long timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
int eor = (sock->type == SOCK_DGRAM) ?
!(msg->msg_flags & MSG_MORE) : !!(msg->msg_flags & MSG_EOR);
int err = -EPIPE;
mutex_lock(&kcm->tx_mutex);
lock_sock(sk);
/* Per tcp_sendmsg this should be in poll */
sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
if (sk->sk_err)
goto out_error;
if (kcm->seq_skb) {
/* Previously opened message */
head = kcm->seq_skb;
skb = kcm_tx_msg(head)->last_skb;
goto start;
}
/* Call the sk_stream functions to manage the sndbuf mem. */
if (!sk_stream_memory_free(sk)) {
kcm_push(kcm);
set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
err = sk_stream_wait_memory(sk, &timeo);
if (err)
goto out_error;
}
if (msg_data_left(msg)) {
/* New message, alloc head skb */
head = alloc_skb(0, sk->sk_allocation);
while (!head) {
kcm_push(kcm);
err = sk_stream_wait_memory(sk, &timeo);
if (err)
goto out_error;
head = alloc_skb(0, sk->sk_allocation);
}
skb = head;
/* Set ip_summed to CHECKSUM_UNNECESSARY to avoid calling
* csum_and_copy_from_iter from skb_do_copy_data_nocache.
*/
skb->ip_summed = CHECKSUM_UNNECESSARY;
}
start:
while (msg_data_left(msg)) {
bool merge = true;
int i = skb_shinfo(skb)->nr_frags;
struct page_frag *pfrag = sk_page_frag(sk);
if (!sk_page_frag_refill(sk, pfrag))
goto wait_for_memory;
if (!skb_can_coalesce(skb, i, pfrag->page,
pfrag->offset)) {
if (i == MAX_SKB_FRAGS) {
struct sk_buff *tskb;
tskb = alloc_skb(0, sk->sk_allocation);
if (!tskb)
goto wait_for_memory;
if (head == skb)
skb_shinfo(head)->frag_list = tskb;
else
skb->next = tskb;
skb = tskb;
skb->ip_summed = CHECKSUM_UNNECESSARY;
continue;
}
merge = false;
}
if (msg->msg_flags & MSG_SPLICE_PAGES) {
copy = msg_data_left(msg);
if (!sk_wmem_schedule(sk, copy))
goto wait_for_memory;
err = skb_splice_from_iter(skb, &msg->msg_iter, copy,
sk->sk_allocation);
if (err < 0) {
if (err == -EMSGSIZE)
goto wait_for_memory;
goto out_error;
}
copy = err;
skb_shinfo(skb)->flags |= SKBFL_SHARED_FRAG;
sk_wmem_queued_add(sk, copy);
sk_mem_charge(sk, copy);
if (head != skb)
head->truesize += copy;
} else {
copy = min_t(int, msg_data_left(msg),
pfrag->size - pfrag->offset);
if (!sk_wmem_schedule(sk, copy))
goto wait_for_memory;
err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb,
pfrag->page,
pfrag->offset,
copy);
if (err)
goto out_error;
/* Update the skb. */
if (merge) {
skb_frag_size_add(
&skb_shinfo(skb)->frags[i - 1], copy);
} else {
skb_fill_page_desc(skb, i, pfrag->page,
pfrag->offset, copy);
get_page(pfrag->page);
}
pfrag->offset += copy;
}
copied += copy;
if (head != skb) {
head->len += copy;
head->data_len += copy;
}
continue;
wait_for_memory:
kcm_push(kcm);
err = sk_stream_wait_memory(sk, &timeo);
if (err)
goto out_error;
}
if (eor) {
bool not_busy = skb_queue_empty(&sk->sk_write_queue);
if (head) {
/* Message complete, queue it on send buffer */
__skb_queue_tail(&sk->sk_write_queue, head);
kcm->seq_skb = NULL;
KCM_STATS_INCR(kcm->stats.tx_msgs);
}
if (msg->msg_flags & MSG_BATCH) {
kcm->tx_wait_more = true;
} else if (kcm->tx_wait_more || not_busy) {
err = kcm_write_msgs(kcm);
if (err < 0) {
/* We got a hard error in write_msgs but have
* already queued this message. Report an error
* in the socket, but don't affect return value
* from sendmsg
*/
pr_warn("KCM: Hard failure on kcm_write_msgs\n");
report_csk_error(&kcm->sk, -err);
}
}
} else {
/* Message not complete, save state */
partial_message:
if (head) {
kcm->seq_skb = head;
kcm_tx_msg(head)->last_skb = skb;
}
}
KCM_STATS_ADD(kcm->stats.tx_bytes, copied);
release_sock(sk);
mutex_unlock(&kcm->tx_mutex);
return copied;
out_error:
kcm_push(kcm);
if (sock->type == SOCK_SEQPACKET) {
/* Wrote some bytes before encountering an
* error, return partial success.
*/
if (copied)
goto partial_message;
if (head != kcm->seq_skb)
kfree_skb(head);
} else {
kfree_skb(head);
kcm->seq_skb = NULL;
}
err = sk_stream_error(sk, msg->msg_flags, err);
/* make sure we wake any epoll edge trigger waiter */
if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 && err == -EAGAIN))
sk->sk_write_space(sk);
release_sock(sk);
mutex_unlock(&kcm->tx_mutex);
return err;
}
static void kcm_splice_eof(struct socket *sock)
{
struct sock *sk = sock->sk;
struct kcm_sock *kcm = kcm_sk(sk);
if (skb_queue_empty_lockless(&sk->sk_write_queue))
return;
lock_sock(sk);
kcm_write_msgs(kcm);
release_sock(sk);
}
static int kcm_recvmsg(struct socket *sock, struct msghdr *msg,
size_t len, int flags)
{
struct sock *sk = sock->sk;
struct kcm_sock *kcm = kcm_sk(sk);
int err = 0;
struct strp_msg *stm;
int copied = 0;
struct sk_buff *skb;
skb = skb_recv_datagram(sk, flags, &err);
if (!skb)
goto out;
/* Okay, have a message on the receive queue */
stm = strp_msg(skb);
if (len > stm->full_len)
len = stm->full_len;
err = skb_copy_datagram_msg(skb, stm->offset, msg, len);
if (err < 0)
goto out;
copied = len;
if (likely(!(flags & MSG_PEEK))) {
KCM_STATS_ADD(kcm->stats.rx_bytes, copied);
if (copied < stm->full_len) {
if (sock->type == SOCK_DGRAM) {
/* Truncated message */
msg->msg_flags |= MSG_TRUNC;
goto msg_finished;
}
stm->offset += copied;
stm->full_len -= copied;
} else {
msg_finished:
/* Finished with message */
msg->msg_flags |= MSG_EOR;
KCM_STATS_INCR(kcm->stats.rx_msgs);
}
}
out:
skb_free_datagram(sk, skb);
return copied ? : err;
}
static ssize_t kcm_splice_read(struct socket *sock, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len,
unsigned int flags)
{
struct sock *sk = sock->sk;
struct kcm_sock *kcm = kcm_sk(sk);
struct strp_msg *stm;
int err = 0;
ssize_t copied;
struct sk_buff *skb;
/* Only support splice for SOCKSEQPACKET */
skb = skb_recv_datagram(sk, flags, &err);
if (!skb)
goto err_out;
/* Okay, have a message on the receive queue */
stm = strp_msg(skb);
if (len > stm->full_len)
len = stm->full_len;
copied = skb_splice_bits(skb, sk, stm->offset, pipe, len, flags);
if (copied < 0) {
err = copied;
goto err_out;
}
KCM_STATS_ADD(kcm->stats.rx_bytes, copied);
stm->offset += copied;
stm->full_len -= copied;
/* We have no way to return MSG_EOR. If all the bytes have been
* read we still leave the message in the receive socket buffer.
* A subsequent recvmsg needs to be done to return MSG_EOR and
* finish reading the message.
*/
skb_free_datagram(sk, skb);
return copied;
err_out:
skb_free_datagram(sk, skb);
return err;
}
/* kcm sock lock held */
static void kcm_recv_disable(struct kcm_sock *kcm)
{
struct kcm_mux *mux = kcm->mux;
if (kcm->rx_disabled)
return;
spin_lock_bh(&mux->rx_lock);
kcm->rx_disabled = 1;
/* If a psock is reserved we'll do cleanup in unreserve */
if (!kcm->rx_psock) {
if (kcm->rx_wait) {
list_del(&kcm->wait_rx_list);
/* paired with lockless reads in kcm_rfree() */
WRITE_ONCE(kcm->rx_wait, false);
}
requeue_rx_msgs(mux, &kcm->sk.sk_receive_queue);
}
spin_unlock_bh(&mux->rx_lock);
}
/* kcm sock lock held */
static void kcm_recv_enable(struct kcm_sock *kcm)
{
struct kcm_mux *mux = kcm->mux;
if (!kcm->rx_disabled)
return;
spin_lock_bh(&mux->rx_lock);
kcm->rx_disabled = 0;
kcm_rcv_ready(kcm);
spin_unlock_bh(&mux->rx_lock);
}
static int kcm_setsockopt(struct socket *sock, int level, int optname,
sockptr_t optval, unsigned int optlen)
{
struct kcm_sock *kcm = kcm_sk(sock->sk);
int val, valbool;
int err = 0;
if (level != SOL_KCM)
return -ENOPROTOOPT;
if (optlen < sizeof(int))
return -EINVAL;
if (copy_from_sockptr(&val, optval, sizeof(int)))
return -EFAULT;
valbool = val ? 1 : 0;
switch (optname) {
case KCM_RECV_DISABLE:
lock_sock(&kcm->sk);
if (valbool)
kcm_recv_disable(kcm);
else
kcm_recv_enable(kcm);
release_sock(&kcm->sk);
break;
default:
err = -ENOPROTOOPT;
}
return err;
}
static int kcm_getsockopt(struct socket *sock, int level, int optname,
char __user *optval, int __user *optlen)
{
struct kcm_sock *kcm = kcm_sk(sock->sk);
int val, len;
if (level != SOL_KCM)
return -ENOPROTOOPT;
if (get_user(len, optlen))
return -EFAULT;
if (len < 0)
return -EINVAL;
len = min_t(unsigned int, len, sizeof(int));
switch (optname) {
case KCM_RECV_DISABLE:
val = kcm->rx_disabled;
break;
default:
return -ENOPROTOOPT;
}
if (put_user(len, optlen))
return -EFAULT;
if (copy_to_user(optval, &val, len))
return -EFAULT;
return 0;
}
static void init_kcm_sock(struct kcm_sock *kcm, struct kcm_mux *mux)
{
struct kcm_sock *tkcm;
struct list_head *head;
int index = 0;
/* For SOCK_SEQPACKET sock type, datagram_poll checks the sk_state, so
* we set sk_state, otherwise epoll_wait always returns right away with
* EPOLLHUP
*/
kcm->sk.sk_state = TCP_ESTABLISHED;
/* Add to mux's kcm sockets list */
kcm->mux = mux;
spin_lock_bh(&mux->lock);
head = &mux->kcm_socks;
list_for_each_entry(tkcm, &mux->kcm_socks, kcm_sock_list) {
if (tkcm->index != index)
break;
head = &tkcm->kcm_sock_list;
index++;
}
list_add(&kcm->kcm_sock_list, head);
kcm->index = index;
mux->kcm_socks_cnt++;
spin_unlock_bh(&mux->lock);
INIT_WORK(&kcm->tx_work, kcm_tx_work);
mutex_init(&kcm->tx_mutex);
spin_lock_bh(&mux->rx_lock);
kcm_rcv_ready(kcm);
spin_unlock_bh(&mux->rx_lock);
}
static int kcm_attach(struct socket *sock, struct socket *csock,
struct bpf_prog *prog)
{
struct kcm_sock *kcm = kcm_sk(sock->sk);
struct kcm_mux *mux = kcm->mux;
struct sock *csk;
struct kcm_psock *psock = NULL, *tpsock;
struct list_head *head;
int index = 0;
static const struct strp_callbacks cb = {
.rcv_msg = kcm_rcv_strparser,
.parse_msg = kcm_parse_func_strparser,
.read_sock_done = kcm_read_sock_done,
};
int err = 0;
csk = csock->sk;
if (!csk)
return -EINVAL;
lock_sock(csk);
/* Only allow TCP sockets to be attached for now */
if ((csk->sk_family != AF_INET && csk->sk_family != AF_INET6) ||
csk->sk_protocol != IPPROTO_TCP) {
err = -EOPNOTSUPP;
goto out;
}
/* Don't allow listeners or closed sockets */
if (csk->sk_state == TCP_LISTEN || csk->sk_state == TCP_CLOSE) {
err = -EOPNOTSUPP;
goto out;
}
psock = kmem_cache_zalloc(kcm_psockp, GFP_KERNEL);
if (!psock) {
err = -ENOMEM;
goto out;
}
psock->mux = mux;
psock->sk = csk;
psock->bpf_prog = prog;
write_lock_bh(&csk->sk_callback_lock);
/* Check if sk_user_data is already by KCM or someone else.
* Must be done under lock to prevent race conditions.
*/
if (csk->sk_user_data) {
write_unlock_bh(&csk->sk_callback_lock);
kmem_cache_free(kcm_psockp, psock);
err = -EALREADY;
goto out;
}
err = strp_init(&psock->strp, csk, &cb);
if (err) {
write_unlock_bh(&csk->sk_callback_lock);
kmem_cache_free(kcm_psockp, psock);
goto out;
}
psock->save_data_ready = csk->sk_data_ready;
psock->save_write_space = csk->sk_write_space;
psock->save_state_change = csk->sk_state_change;
csk->sk_user_data = psock;
csk->sk_data_ready = psock_data_ready;
csk->sk_write_space = psock_write_space;
csk->sk_state_change = psock_state_change;
write_unlock_bh(&csk->sk_callback_lock);
sock_hold(csk);
/* Finished initialization, now add the psock to the MUX. */
spin_lock_bh(&mux->lock);
head = &mux->psocks;
list_for_each_entry(tpsock, &mux->psocks, psock_list) {
if (tpsock->index != index)
break;
head = &tpsock->psock_list;
index++;
}
list_add(&psock->psock_list, head);
psock->index = index;
KCM_STATS_INCR(mux->stats.psock_attach);
mux->psocks_cnt++;
psock_now_avail(psock);
spin_unlock_bh(&mux->lock);
/* Schedule RX work in case there are already bytes queued */
strp_check_rcv(&psock->strp);
out:
release_sock(csk);
return err;
}
static int kcm_attach_ioctl(struct socket *sock, struct kcm_attach *info)
{
struct socket *csock;
struct bpf_prog *prog;
int err;
csock = sockfd_lookup(info->fd, &err);
if (!csock)
return -ENOENT;
prog = bpf_prog_get_type(info->bpf_fd, BPF_PROG_TYPE_SOCKET_FILTER);
if (IS_ERR(prog)) {
err = PTR_ERR(prog);
goto out;
}
err = kcm_attach(sock, csock, prog);
if (err) {
bpf_prog_put(prog);
goto out;
}
/* Keep reference on file also */
return 0;
out:
sockfd_put(csock);
return err;
}
static void kcm_unattach(struct kcm_psock *psock)
{
struct sock *csk = psock->sk;
struct kcm_mux *mux = psock->mux;
lock_sock(csk);
/* Stop getting callbacks from TCP socket. After this there should
* be no way to reserve a kcm for this psock.
*/
write_lock_bh(&csk->sk_callback_lock);
csk->sk_user_data = NULL;
csk->sk_data_ready = psock->save_data_ready;
csk->sk_write_space = psock->save_write_space;
csk->sk_state_change = psock->save_state_change;
strp_stop(&psock->strp);
if (WARN_ON(psock->rx_kcm)) {
write_unlock_bh(&csk->sk_callback_lock);
release_sock(csk);
return;
}
spin_lock_bh(&mux->rx_lock);
/* Stop receiver activities. After this point psock should not be
* able to get onto ready list either through callbacks or work.
*/
if (psock->ready_rx_msg) {
list_del(&psock->psock_ready_list);
kfree_skb(psock->ready_rx_msg);
psock->ready_rx_msg = NULL;
KCM_STATS_INCR(mux->stats.rx_ready_drops);
}
spin_unlock_bh(&mux->rx_lock);
write_unlock_bh(&csk->sk_callback_lock);
/* Call strp_done without sock lock */
release_sock(csk);
strp_done(&psock->strp);
lock_sock(csk);
bpf_prog_put(psock->bpf_prog);
spin_lock_bh(&mux->lock);
aggregate_psock_stats(&psock->stats, &mux->aggregate_psock_stats);
save_strp_stats(&psock->strp, &mux->aggregate_strp_stats);
KCM_STATS_INCR(mux->stats.psock_unattach);
if (psock->tx_kcm) {
/* psock was reserved. Just mark it finished and we will clean
* up in the kcm paths, we need kcm lock which can not be
* acquired here.
*/
KCM_STATS_INCR(mux->stats.psock_unattach_rsvd);
spin_unlock_bh(&mux->lock);
/* We are unattaching a socket that is reserved. Abort the
* socket since we may be out of sync in sending on it. We need
* to do this without the mux lock.
*/
kcm_abort_tx_psock(psock, EPIPE, false);
spin_lock_bh(&mux->lock);
if (!psock->tx_kcm) {
/* psock now unreserved in window mux was unlocked */
goto no_reserved;
}
psock->done = 1;
/* Commit done before queuing work to process it */
smp_mb();
/* Queue tx work to make sure psock->done is handled */
queue_work(kcm_wq, &psock->tx_kcm->tx_work);
spin_unlock_bh(&mux->lock);
} else {
no_reserved:
if (!psock->tx_stopped)
list_del(&psock->psock_avail_list);
list_del(&psock->psock_list);
mux->psocks_cnt--;
spin_unlock_bh(&mux->lock);
sock_put(csk);
fput(csk->sk_socket->file);
kmem_cache_free(kcm_psockp, psock);
}
release_sock(csk);
}
static int kcm_unattach_ioctl(struct socket *sock, struct kcm_unattach *info)
{
struct kcm_sock *kcm = kcm_sk(sock->sk);
struct kcm_mux *mux = kcm->mux;
struct kcm_psock *psock;
struct socket *csock;
struct sock *csk;
int err;
csock = sockfd_lookup(info->fd, &err);
if (!csock)
return -ENOENT;
csk = csock->sk;
if (!csk) {
err = -EINVAL;
goto out;
}
err = -ENOENT;
spin_lock_bh(&mux->lock);
list_for_each_entry(psock, &mux->psocks, psock_list) {
if (psock->sk != csk)
continue;
/* Found the matching psock */
if (psock->unattaching || WARN_ON(psock->done)) {
err = -EALREADY;
break;
}
psock->unattaching = 1;
spin_unlock_bh(&mux->lock);
/* Lower socket lock should already be held */
kcm_unattach(psock);
err = 0;
goto out;
}
spin_unlock_bh(&mux->lock);
out:
sockfd_put(csock);
return err;
}
static struct proto kcm_proto = {
.name = "KCM",
.owner = THIS_MODULE,
.obj_size = sizeof(struct kcm_sock),
};
/* Clone a kcm socket. */
static struct file *kcm_clone(struct socket *osock)
{
struct socket *newsock;
struct sock *newsk;
newsock = sock_alloc();
if (!newsock)
return ERR_PTR(-ENFILE);
newsock->type = osock->type;
newsock->ops = osock->ops;
__module_get(newsock->ops->owner);
newsk = sk_alloc(sock_net(osock->sk), PF_KCM, GFP_KERNEL,
&kcm_proto, false);
if (!newsk) {
sock_release(newsock);
return ERR_PTR(-ENOMEM);
}
sock_init_data(newsock, newsk);
init_kcm_sock(kcm_sk(newsk), kcm_sk(osock->sk)->mux);
return sock_alloc_file(newsock, 0, osock->sk->sk_prot_creator->name);
}
static int kcm_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
int err;
switch (cmd) {
case SIOCKCMATTACH: {
struct kcm_attach info;
if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
return -EFAULT;
err = kcm_attach_ioctl(sock, &info);
break;
}
case SIOCKCMUNATTACH: {
struct kcm_unattach info;
if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
return -EFAULT;
err = kcm_unattach_ioctl(sock, &info);
break;
}
case SIOCKCMCLONE: {
struct kcm_clone info;
struct file *file;
info.fd = get_unused_fd_flags(0);
if (unlikely(info.fd < 0))
return info.fd;
file = kcm_clone(sock);
if (IS_ERR(file)) {
put_unused_fd(info.fd);
return PTR_ERR(file);
}
if (copy_to_user((void __user *)arg, &info,
sizeof(info))) {
put_unused_fd(info.fd);
fput(file);
return -EFAULT;
}
fd_install(info.fd, file);
err = 0;
break;
}
default:
err = -ENOIOCTLCMD;
break;
}
return err;
}
static void free_mux(struct rcu_head *rcu)
{
struct kcm_mux *mux = container_of(rcu,
struct kcm_mux, rcu);
kmem_cache_free(kcm_muxp, mux);
}
static void release_mux(struct kcm_mux *mux)
{
struct kcm_net *knet = mux->knet;
struct kcm_psock *psock, *tmp_psock;
/* Release psocks */
list_for_each_entry_safe(psock, tmp_psock,
&mux->psocks, psock_list) {
if (!WARN_ON(psock->unattaching))
kcm_unattach(psock);
}
if (WARN_ON(mux->psocks_cnt))
return;
__skb_queue_purge(&mux->rx_hold_queue);
mutex_lock(&knet->mutex);
aggregate_mux_stats(&mux->stats, &knet->aggregate_mux_stats);
aggregate_psock_stats(&mux->aggregate_psock_stats,
&knet->aggregate_psock_stats);
aggregate_strp_stats(&mux->aggregate_strp_stats,
&knet->aggregate_strp_stats);
list_del_rcu(&mux->kcm_mux_list);
knet->count--;
mutex_unlock(&knet->mutex);
call_rcu(&mux->rcu, free_mux);
}
static void kcm_done(struct kcm_sock *kcm)
{
struct kcm_mux *mux = kcm->mux;
struct sock *sk = &kcm->sk;
int socks_cnt;
spin_lock_bh(&mux->rx_lock);
if (kcm->rx_psock) {
/* Cleanup in unreserve_rx_kcm */
WARN_ON(kcm->done);
kcm->rx_disabled = 1;
kcm->done = 1;
spin_unlock_bh(&mux->rx_lock);
return;
}
if (kcm->rx_wait) {
list_del(&kcm->wait_rx_list);
/* paired with lockless reads in kcm_rfree() */
WRITE_ONCE(kcm->rx_wait, false);
}
/* Move any pending receive messages to other kcm sockets */
requeue_rx_msgs(mux, &sk->sk_receive_queue);
spin_unlock_bh(&mux->rx_lock);
if (WARN_ON(sk_rmem_alloc_get(sk)))
return;
/* Detach from MUX */
spin_lock_bh(&mux->lock);
list_del(&kcm->kcm_sock_list);
mux->kcm_socks_cnt--;
socks_cnt = mux->kcm_socks_cnt;
spin_unlock_bh(&mux->lock);
if (!socks_cnt) {
/* We are done with the mux now. */
release_mux(mux);
}
WARN_ON(kcm->rx_wait);
sock_put(&kcm->sk);
}
/* Called by kcm_release to close a KCM socket.
* If this is the last KCM socket on the MUX, destroy the MUX.
*/
static int kcm_release(struct socket *sock)
{
struct sock *sk = sock->sk;
struct kcm_sock *kcm;
struct kcm_mux *mux;
struct kcm_psock *psock;
if (!sk)
return 0;
kcm = kcm_sk(sk);
mux = kcm->mux;
lock_sock(sk);
sock_orphan(sk);
kfree_skb(kcm->seq_skb);
/* Purge queue under lock to avoid race condition with tx_work trying
* to act when queue is nonempty. If tx_work runs after this point
* it will just return.
*/
__skb_queue_purge(&sk->sk_write_queue);
/* Set tx_stopped. This is checked when psock is bound to a kcm and we
* get a writespace callback. This prevents further work being queued
* from the callback (unbinding the psock occurs after canceling work.
*/
kcm->tx_stopped = 1;
release_sock(sk);
spin_lock_bh(&mux->lock);
if (kcm->tx_wait) {
/* Take of tx_wait list, after this point there should be no way
* that a psock will be assigned to this kcm.
*/
list_del(&kcm->wait_psock_list);
kcm->tx_wait = false;
}
spin_unlock_bh(&mux->lock);
/* Cancel work. After this point there should be no outside references
* to the kcm socket.
*/
cancel_work_sync(&kcm->tx_work);
lock_sock(sk);
psock = kcm->tx_psock;
if (psock) {
/* A psock was reserved, so we need to kill it since it
* may already have some bytes queued from a message. We
* need to do this after removing kcm from tx_wait list.
*/
kcm_abort_tx_psock(psock, EPIPE, false);
unreserve_psock(kcm);
}
release_sock(sk);
WARN_ON(kcm->tx_wait);
WARN_ON(kcm->tx_psock);
sock->sk = NULL;
kcm_done(kcm);
return 0;
}
static const struct proto_ops kcm_dgram_ops = {
.family = PF_KCM,
.owner = THIS_MODULE,
.release = kcm_release,
.bind = sock_no_bind,
.connect = sock_no_connect,
.socketpair = sock_no_socketpair,
.accept = sock_no_accept,
.getname = sock_no_getname,
.poll = datagram_poll,
.ioctl = kcm_ioctl,
.listen = sock_no_listen,
.shutdown = sock_no_shutdown,
.setsockopt = kcm_setsockopt,
.getsockopt = kcm_getsockopt,
.sendmsg = kcm_sendmsg,
.recvmsg = kcm_recvmsg,
.mmap = sock_no_mmap,
.splice_eof = kcm_splice_eof,
};
static const struct proto_ops kcm_seqpacket_ops = {
.family = PF_KCM,
.owner = THIS_MODULE,
.release = kcm_release,
.bind = sock_no_bind,
.connect = sock_no_connect,
.socketpair = sock_no_socketpair,
.accept = sock_no_accept,
.getname = sock_no_getname,
.poll = datagram_poll,
.ioctl = kcm_ioctl,
.listen = sock_no_listen,
.shutdown = sock_no_shutdown,
.setsockopt = kcm_setsockopt,
.getsockopt = kcm_getsockopt,
.sendmsg = kcm_sendmsg,
.recvmsg = kcm_recvmsg,
.mmap = sock_no_mmap,
.splice_eof = kcm_splice_eof,
.splice_read = kcm_splice_read,
};
/* Create proto operation for kcm sockets */
static int kcm_create(struct net *net, struct socket *sock,
int protocol, int kern)
{
struct kcm_net *knet = net_generic(net, kcm_net_id);
struct sock *sk;
struct kcm_mux *mux;
switch (sock->type) {
case SOCK_DGRAM:
sock->ops = &kcm_dgram_ops;
break;
case SOCK_SEQPACKET:
sock->ops = &kcm_seqpacket_ops;
break;
default:
return -ESOCKTNOSUPPORT;
}
if (protocol != KCMPROTO_CONNECTED)
return -EPROTONOSUPPORT;
sk = sk_alloc(net, PF_KCM, GFP_KERNEL, &kcm_proto, kern);
if (!sk)
return -ENOMEM;
/* Allocate a kcm mux, shared between KCM sockets */
mux = kmem_cache_zalloc(kcm_muxp, GFP_KERNEL);
if (!mux) {
sk_free(sk);
return -ENOMEM;
}
spin_lock_init(&mux->lock);
spin_lock_init(&mux->rx_lock);
INIT_LIST_HEAD(&mux->kcm_socks);
INIT_LIST_HEAD(&mux->kcm_rx_waiters);
INIT_LIST_HEAD(&mux->kcm_tx_waiters);
INIT_LIST_HEAD(&mux->psocks);
INIT_LIST_HEAD(&mux->psocks_ready);
INIT_LIST_HEAD(&mux->psocks_avail);
mux->knet = knet;
/* Add new MUX to list */
mutex_lock(&knet->mutex);
list_add_rcu(&mux->kcm_mux_list, &knet->mux_list);
knet->count++;
mutex_unlock(&knet->mutex);
skb_queue_head_init(&mux->rx_hold_queue);
/* Init KCM socket */
sock_init_data(sock, sk);
init_kcm_sock(kcm_sk(sk), mux);
return 0;
}
static const struct net_proto_family kcm_family_ops = {
.family = PF_KCM,
.create = kcm_create,
.owner = THIS_MODULE,
};
static __net_init int kcm_init_net(struct net *net)
{
struct kcm_net *knet = net_generic(net, kcm_net_id);
INIT_LIST_HEAD_RCU(&knet->mux_list);
mutex_init(&knet->mutex);
return 0;
}
static __net_exit void kcm_exit_net(struct net *net)
{
struct kcm_net *knet = net_generic(net, kcm_net_id);
/* All KCM sockets should be closed at this point, which should mean
* that all multiplexors and psocks have been destroyed.
*/
WARN_ON(!list_empty(&knet->mux_list));
mutex_destroy(&knet->mutex);
}
static struct pernet_operations kcm_net_ops = {
.init = kcm_init_net,
.exit = kcm_exit_net,
.id = &kcm_net_id,
.size = sizeof(struct kcm_net),
};
static int __init kcm_init(void)
{
int err = -ENOMEM;
kcm_muxp = KMEM_CACHE(kcm_mux, SLAB_HWCACHE_ALIGN);
if (!kcm_muxp)
goto fail;
kcm_psockp = KMEM_CACHE(kcm_psock, SLAB_HWCACHE_ALIGN);
if (!kcm_psockp)
goto fail;
kcm_wq = create_singlethread_workqueue("kkcmd");
if (!kcm_wq)
goto fail;
err = proto_register(&kcm_proto, 1);
if (err)
goto fail;
err = register_pernet_device(&kcm_net_ops);
if (err)
goto net_ops_fail;
err = sock_register(&kcm_family_ops);
if (err)
goto sock_register_fail;
err = kcm_proc_init();
if (err)
goto proc_init_fail;
return 0;
proc_init_fail:
sock_unregister(PF_KCM);
sock_register_fail:
unregister_pernet_device(&kcm_net_ops);
net_ops_fail:
proto_unregister(&kcm_proto);
fail:
kmem_cache_destroy(kcm_muxp);
kmem_cache_destroy(kcm_psockp);
if (kcm_wq)
destroy_workqueue(kcm_wq);
return err;
}
static void __exit kcm_exit(void)
{
kcm_proc_exit();
sock_unregister(PF_KCM);
unregister_pernet_device(&kcm_net_ops);
proto_unregister(&kcm_proto);
destroy_workqueue(kcm_wq);
kmem_cache_destroy(kcm_muxp);
kmem_cache_destroy(kcm_psockp);
}
module_init(kcm_init);
module_exit(kcm_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("KCM (Kernel Connection Multiplexor) sockets");
MODULE_ALIAS_NETPROTO(PF_KCM);
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