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linux-sg2042/net/kcm/kcmsock.c

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#include <linux/bpf.h>
#include <linux/errno.h>
#include <linux/errqueue.h>
#include <linux/file.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 <net/kcm.h>
#include <net/netns/generic.h>
#include <net/sock.h>
#include <net/tcp.h>
#include <uapi/linux/kcm.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 inline struct kcm_rx_msg *kcm_rx_msg(struct sk_buff *skb)
{
return (struct kcm_rx_msg *)((void *)skb->cb +
offsetof(struct qdisc_skb_cb, data));
}
static void report_csk_error(struct sock *csk, int err)
{
csk->sk_err = EPIPE;
csk->sk_error_report(csk);
}
/* Callback lock held */
static void kcm_abort_rx_psock(struct kcm_psock *psock, int err,
struct sk_buff *skb)
{
struct sock *csk = psock->sk;
/* Unrecoverable error in receive */
del_timer(&psock->rx_msg_timer);
if (psock->rx_stopped)
return;
psock->rx_stopped = 1;
KCM_STATS_INCR(psock->stats.rx_aborts);
/* Report an error on the lower socket */
report_csk_error(csk, err);
}
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)
{
KCM_STATS_ADD(mux->stats.rx_bytes,
psock->stats.rx_bytes - psock->saved_rx_bytes);
mux->stats.rx_msgs +=
psock->stats.rx_msgs - psock->saved_rx_msgs;
psock->saved_rx_msgs = psock->stats.rx_msgs;
psock->saved_rx_bytes = psock->stats.rx_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();
queue_work(kcm_wq, &psock->rx_work);
}
/* Buffer limit is okay now, add to ready list */
list_add_tail(&kcm->wait_rx_list,
&kcm->mux->kcm_rx_waiters);
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 (!kcm->rx_wait && !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);
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;
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);
kcm->rx_wait = false;
psock->rx_kcm = kcm;
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;
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);
}
static void kcm_start_rx_timer(struct kcm_psock *psock)
{
if (psock->sk->sk_rcvtimeo)
mod_timer(&psock->rx_msg_timer, psock->sk->sk_rcvtimeo);
}
/* Macro to invoke filter function. */
#define KCM_RUN_FILTER(prog, ctx) \
(*prog->bpf_func)(ctx, prog->insnsi)
/* Lower socket lock held */
static int kcm_tcp_recv(read_descriptor_t *desc, struct sk_buff *orig_skb,
unsigned int orig_offset, size_t orig_len)
{
struct kcm_psock *psock = (struct kcm_psock *)desc->arg.data;
struct kcm_rx_msg *rxm;
struct kcm_sock *kcm;
struct sk_buff *head, *skb;
size_t eaten = 0, cand_len;
ssize_t extra;
int err;
bool cloned_orig = false;
if (psock->ready_rx_msg)
return 0;
head = psock->rx_skb_head;
if (head) {
/* Message already in progress */
rxm = kcm_rx_msg(head);
if (unlikely(rxm->early_eaten)) {
/* Already some number of bytes on the receive sock
* data saved in rx_skb_head, just indicate they
* are consumed.
*/
eaten = orig_len <= rxm->early_eaten ?
orig_len : rxm->early_eaten;
rxm->early_eaten -= eaten;
return eaten;
}
if (unlikely(orig_offset)) {
/* Getting data with a non-zero offset when a message is
* in progress is not expected. If it does happen, we
* need to clone and pull since we can't deal with
* offsets in the skbs for a message expect in the head.
*/
orig_skb = skb_clone(orig_skb, GFP_ATOMIC);
if (!orig_skb) {
KCM_STATS_INCR(psock->stats.rx_mem_fail);
desc->error = -ENOMEM;
return 0;
}
if (!pskb_pull(orig_skb, orig_offset)) {
KCM_STATS_INCR(psock->stats.rx_mem_fail);
kfree_skb(orig_skb);
desc->error = -ENOMEM;
return 0;
}
cloned_orig = true;
orig_offset = 0;
}
if (!psock->rx_skb_nextp) {
/* We are going to append to the frags_list of head.
* Need to unshare the frag_list.
*/
err = skb_unclone(head, GFP_ATOMIC);
if (err) {
KCM_STATS_INCR(psock->stats.rx_mem_fail);
desc->error = err;
return 0;
}
if (unlikely(skb_shinfo(head)->frag_list)) {
/* We can't append to an sk_buff that already
* has a frag_list. We create a new head, point
* the frag_list of that to the old head, and
* then are able to use the old head->next for
* appending to the message.
*/
if (WARN_ON(head->next)) {
desc->error = -EINVAL;
return 0;
}
skb = alloc_skb(0, GFP_ATOMIC);
if (!skb) {
KCM_STATS_INCR(psock->stats.rx_mem_fail);
desc->error = -ENOMEM;
return 0;
}
skb->len = head->len;
skb->data_len = head->len;
skb->truesize = head->truesize;
*kcm_rx_msg(skb) = *kcm_rx_msg(head);
psock->rx_skb_nextp = &head->next;
skb_shinfo(skb)->frag_list = head;
psock->rx_skb_head = skb;
head = skb;
} else {
psock->rx_skb_nextp =
&skb_shinfo(head)->frag_list;
}
}
}
while (eaten < orig_len) {
/* Always clone since we will consume something */
skb = skb_clone(orig_skb, GFP_ATOMIC);
if (!skb) {
KCM_STATS_INCR(psock->stats.rx_mem_fail);
desc->error = -ENOMEM;
break;
}
cand_len = orig_len - eaten;
head = psock->rx_skb_head;
if (!head) {
head = skb;
psock->rx_skb_head = head;
/* Will set rx_skb_nextp on next packet if needed */
psock->rx_skb_nextp = NULL;
rxm = kcm_rx_msg(head);
memset(rxm, 0, sizeof(*rxm));
rxm->offset = orig_offset + eaten;
} else {
/* Unclone since we may be appending to an skb that we
* already share a frag_list with.
*/
err = skb_unclone(skb, GFP_ATOMIC);
if (err) {
KCM_STATS_INCR(psock->stats.rx_mem_fail);
desc->error = err;
break;
}
rxm = kcm_rx_msg(head);
*psock->rx_skb_nextp = skb;
psock->rx_skb_nextp = &skb->next;
head->data_len += skb->len;
head->len += skb->len;
head->truesize += skb->truesize;
}
if (!rxm->full_len) {
ssize_t len;
len = KCM_RUN_FILTER(psock->bpf_prog, head);
if (!len) {
/* Need more header to determine length */
if (!rxm->accum_len) {
/* Start RX timer for new message */
kcm_start_rx_timer(psock);
}
rxm->accum_len += cand_len;
eaten += cand_len;
KCM_STATS_INCR(psock->stats.rx_need_more_hdr);
WARN_ON(eaten != orig_len);
break;
} else if (len > psock->sk->sk_rcvbuf) {
/* Message length exceeds maximum allowed */
KCM_STATS_INCR(psock->stats.rx_msg_too_big);
desc->error = -EMSGSIZE;
psock->rx_skb_head = NULL;
kcm_abort_rx_psock(psock, EMSGSIZE, head);
break;
} else if (len <= (ssize_t)head->len -
skb->len - rxm->offset) {
/* Length must be into new skb (and also
* greater than zero)
*/
KCM_STATS_INCR(psock->stats.rx_bad_hdr_len);
desc->error = -EPROTO;
psock->rx_skb_head = NULL;
kcm_abort_rx_psock(psock, EPROTO, head);
break;
}
rxm->full_len = len;
}
extra = (ssize_t)(rxm->accum_len + cand_len) - rxm->full_len;
if (extra < 0) {
/* Message not complete yet. */
if (rxm->full_len - rxm->accum_len >
tcp_inq(psock->sk)) {
/* Don't have the whole messages in the socket
* buffer. Set psock->rx_need_bytes to wait for
* the rest of the message. Also, set "early
* eaten" since we've already buffered the skb
* but don't consume yet per tcp_read_sock.
*/
if (!rxm->accum_len) {
/* Start RX timer for new message */
kcm_start_rx_timer(psock);
}
psock->rx_need_bytes = rxm->full_len -
rxm->accum_len;
rxm->accum_len += cand_len;
rxm->early_eaten = cand_len;
KCM_STATS_ADD(psock->stats.rx_bytes, cand_len);
desc->count = 0; /* Stop reading socket */
break;
}
rxm->accum_len += cand_len;
eaten += cand_len;
WARN_ON(eaten != orig_len);
break;
}
/* Positive extra indicates ore bytes than needed for the
* message
*/
WARN_ON(extra > cand_len);
eaten += (cand_len - extra);
/* Hurray, we have a new message! */
del_timer(&psock->rx_msg_timer);
psock->rx_skb_head = NULL;
KCM_STATS_INCR(psock->stats.rx_msgs);
try_queue:
kcm = reserve_rx_kcm(psock, head);
if (!kcm) {
/* Unable to reserve a KCM, message is held in psock. */
break;
}
if (kcm_queue_rcv_skb(&kcm->sk, head)) {
/* Should mean socket buffer full */
unreserve_rx_kcm(psock, false);
goto try_queue;
}
}
if (cloned_orig)
kfree_skb(orig_skb);
KCM_STATS_ADD(psock->stats.rx_bytes, eaten);
return eaten;
}
/* Called with lock held on lower socket */
static int psock_tcp_read_sock(struct kcm_psock *psock)
{
read_descriptor_t desc;
desc.arg.data = psock;
desc.error = 0;
desc.count = 1; /* give more than one skb per call */
/* sk should be locked here, so okay to do tcp_read_sock */
tcp_read_sock(psock->sk, &desc, kcm_tcp_recv);
unreserve_rx_kcm(psock, true);
return desc.error;
}
/* Lower sock lock held */
static void psock_tcp_data_ready(struct sock *sk)
{
struct kcm_psock *psock;
read_lock_bh(&sk->sk_callback_lock);
psock = (struct kcm_psock *)sk->sk_user_data;
if (unlikely(!psock || psock->rx_stopped))
goto out;
if (psock->ready_rx_msg)
goto out;
if (psock->rx_need_bytes) {
if (tcp_inq(sk) >= psock->rx_need_bytes)
psock->rx_need_bytes = 0;
else
goto out;
}
if (psock_tcp_read_sock(psock) == -ENOMEM)
queue_delayed_work(kcm_wq, &psock->rx_delayed_work, 0);
out:
read_unlock_bh(&sk->sk_callback_lock);
}
static void do_psock_rx_work(struct kcm_psock *psock)
{
read_descriptor_t rd_desc;
struct sock *csk = psock->sk;
/* We need the read lock to synchronize with psock_tcp_data_ready. We
* need the socket lock for calling tcp_read_sock.
*/
lock_sock(csk);
read_lock_bh(&csk->sk_callback_lock);
if (unlikely(csk->sk_user_data != psock))
goto out;
if (unlikely(psock->rx_stopped))
goto out;
if (psock->ready_rx_msg)
goto out;
rd_desc.arg.data = psock;
if (psock_tcp_read_sock(psock) == -ENOMEM)
queue_delayed_work(kcm_wq, &psock->rx_delayed_work, 0);
out:
read_unlock_bh(&csk->sk_callback_lock);
release_sock(csk);
}
static void psock_rx_work(struct work_struct *w)
{
do_psock_rx_work(container_of(w, struct kcm_psock, rx_work));
}
static void psock_rx_delayed_work(struct work_struct *w)
{
do_psock_rx_work(container_of(w, struct kcm_psock,
rx_delayed_work.work));
}
static void psock_tcp_state_change(struct sock *sk)
{
/* TCP only does a POLLIN for a half close. Do a POLLHUP here
* since application will normally not poll with POLLIN
* on the TCP sockets.
*/
report_csk_error(sk, EPIPE);
}
static void psock_tcp_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)
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)
{
struct sock *sk = &kcm->sk;
struct kcm_psock *psock;
struct sk_buff *skb, *head;
struct kcm_tx_msg *txm;
unsigned short fragidx, frag_offset;
unsigned int sent, total_sent = 0;
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))->sent = 0;
} else if (skb_queue_empty(&sk->sk_write_queue)) {
return 0;
}
head = skb_peek(&sk->sk_write_queue);
txm = kcm_tx_msg(head);
if (txm->sent) {
/* Send of first skbuff in queue already in progress */
if (WARN_ON(!psock)) {
ret = -EINVAL;
goto out;
}
sent = txm->sent;
frag_offset = txm->frag_offset;
fragidx = txm->fragidx;
skb = txm->frag_skb;
goto do_frag;
}
try_again:
psock = reserve_psock(kcm);
if (!psock)
goto out;
do {
skb = head;
txm = kcm_tx_msg(head);
sent = 0;
do_frag_list:
if (WARN_ON(!skb_shinfo(skb)->nr_frags)) {
ret = -EINVAL;
goto out;
}
for (fragidx = 0; fragidx < skb_shinfo(skb)->nr_frags;
fragidx++) {
skb_frag_t *frag;
frag_offset = 0;
do_frag:
frag = &skb_shinfo(skb)->frags[fragidx];
if (WARN_ON(!frag->size)) {
ret = -EINVAL;
goto out;
}
ret = kernel_sendpage(psock->sk->sk_socket,
frag->page.p,
frag->page_offset + frag_offset,
frag->size - frag_offset,
MSG_DONTWAIT);
if (ret <= 0) {
if (ret == -EAGAIN) {
/* Save state to try again when there's
* write space on the socket
*/
txm->sent = sent;
txm->frag_offset = frag_offset;
txm->fragidx = fragidx;
txm->frag_skb = skb;
ret = 0;
goto out;
}
/* Hard failure in sending message, abort this
* psock since it has lost framing
* synchonization and retry sending the
* message from the beginning.
*/
kcm_abort_tx_psock(psock, ret ? -ret : EPIPE,
true);
unreserve_psock(kcm);
txm->sent = 0;
kcm_report_tx_retry(kcm);
ret = 0;
goto try_again;
}
sent += ret;
frag_offset += ret;
KCM_STATS_ADD(psock->stats.tx_bytes, ret);
if (frag_offset < frag->size) {
/* Not finished with this frag */
goto do_frag;
}
}
if (skb == head) {
if (skb_has_frag_list(skb)) {
skb = skb_shinfo(skb)->frag_list;
goto do_frag_list;
}
} else if (skb->next) {
skb = skb->next;
goto do_frag_list;
}
/* Successfully sent the whole packet, account for it. */
skb_dequeue(&sk->sk_write_queue);
kfree_skb(head);
sk->sk_wmem_queued -= sent;
total_sent += sent;
KCM_STATS_INCR(psock->stats.tx_msgs);
} while ((head = skb_peek(&sk->sk_write_queue)));
out:
if (!head) {
/* Done with all queued messages. */
WARN_ON(!skb_queue_empty(&sk->sk_write_queue));
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 ssize_t kcm_sendpage(struct socket *sock, struct page *page,
int offset, size_t size, int flags)
{
struct sock *sk = sock->sk;
struct kcm_sock *kcm = kcm_sk(sk);
struct sk_buff *skb = NULL, *head = NULL;
long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
bool eor;
int err = 0;
int i;
if (flags & MSG_SENDPAGE_NOTLAST)
flags |= MSG_MORE;
/* No MSG_EOR from splice, only look at MSG_MORE */
eor = !(flags & MSG_MORE);
lock_sock(sk);
sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
err = -EPIPE;
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;
i = skb_shinfo(skb)->nr_frags;
if (skb_can_coalesce(skb, i, page, offset)) {
skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], size);
skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
goto coalesced;
}
if (i >= MAX_SKB_FRAGS) {
struct sk_buff *tskb;
tskb = alloc_skb(0, sk->sk_allocation);
while (!tskb) {
kcm_push(kcm);
err = sk_stream_wait_memory(sk, &timeo);
if (err)
goto out_error;
}
if (head == skb)
skb_shinfo(head)->frag_list = tskb;
else
skb->next = tskb;
skb = tskb;
skb->ip_summed = CHECKSUM_UNNECESSARY;
i = 0;
}
} else {
/* 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;
}
head = alloc_skb(0, sk->sk_allocation);
while (!head) {
kcm_push(kcm);
err = sk_stream_wait_memory(sk, &timeo);
if (err)
goto out_error;
}
skb = head;
i = 0;
}
get_page(page);
skb_fill_page_desc(skb, i, page, offset, size);
skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
coalesced:
skb->len += size;
skb->data_len += size;
skb->truesize += size;
sk->sk_wmem_queued += size;
sk_mem_charge(sk, size);
if (head != skb) {
head->len += size;
head->data_len += size;
head->truesize += size;
}
if (eor) {
bool not_busy = skb_queue_empty(&sk->sk_write_queue);
/* 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 (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 */
kcm->seq_skb = head;
kcm_tx_msg(head)->last_skb = skb;
}
KCM_STATS_ADD(kcm->stats.tx_bytes, size);
release_sock(sk);
return size;
out_error:
kcm_push(kcm);
err = sk_stream_error(sk, 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);
return err;
}
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;
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;
}
/* 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;
}
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);
/* 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:
kcm->seq_skb = head;
kcm_tx_msg(head)->last_skb = skb;
}
KCM_STATS_ADD(kcm->stats.tx_bytes, copied);
release_sock(sk);
return copied;
out_error:
kcm_push(kcm);
if (copied && sock->type == SOCK_SEQPACKET) {
/* Wrote some bytes before encountering an
* error, return partial success.
*/
goto partial_message;
}
if (head != kcm->seq_skb)
kfree_skb(head);
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);
return err;
}
static struct sk_buff *kcm_wait_data(struct sock *sk, int flags,
long timeo, int *err)
{
struct sk_buff *skb;
while (!(skb = skb_peek(&sk->sk_receive_queue))) {
if (sk->sk_err) {
*err = sock_error(sk);
return NULL;
}
if (sock_flag(sk, SOCK_DONE))
return NULL;
if ((flags & MSG_DONTWAIT) || !timeo) {
*err = -EAGAIN;
return NULL;
}
sk_wait_data(sk, &timeo, NULL);
/* Handle signals */
if (signal_pending(current)) {
*err = sock_intr_errno(timeo);
return NULL;
}
}
return skb;
}
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;
long timeo;
struct kcm_rx_msg *rxm;
int copied = 0;
struct sk_buff *skb;
timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
lock_sock(sk);
skb = kcm_wait_data(sk, flags, timeo, &err);
if (!skb)
goto out;
/* Okay, have a message on the receive queue */
rxm = kcm_rx_msg(skb);
if (len > rxm->full_len)
len = rxm->full_len;
err = skb_copy_datagram_msg(skb, rxm->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 < rxm->full_len) {
if (sock->type == SOCK_DGRAM) {
/* Truncated message */
msg->msg_flags |= MSG_TRUNC;
goto msg_finished;
}
rxm->offset += copied;
rxm->full_len -= copied;
} else {
msg_finished:
/* Finished with message */
msg->msg_flags |= MSG_EOR;
KCM_STATS_INCR(kcm->stats.rx_msgs);
skb_unlink(skb, &sk->sk_receive_queue);
kfree_skb(skb);
}
}
out:
release_sock(sk);
return copied ? : err;
}
static ssize_t kcm_sock_splice(struct sock *sk,
struct pipe_inode_info *pipe,
struct splice_pipe_desc *spd)
{
int ret;
release_sock(sk);
ret = splice_to_pipe(pipe, spd);
lock_sock(sk);
return ret;
}
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);
long timeo;
struct kcm_rx_msg *rxm;
int err = 0;
ssize_t copied;
struct sk_buff *skb;
/* Only support splice for SOCKSEQPACKET */
timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
lock_sock(sk);
skb = kcm_wait_data(sk, flags, timeo, &err);
if (!skb)
goto err_out;
/* Okay, have a message on the receive queue */
rxm = kcm_rx_msg(skb);
if (len > rxm->full_len)
len = rxm->full_len;
copied = skb_splice_bits(skb, sk, rxm->offset, pipe, len, flags,
kcm_sock_splice);
if (copied < 0) {
err = copied;
goto err_out;
}
KCM_STATS_ADD(kcm->stats.rx_bytes, copied);
rxm->offset += copied;
rxm->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.
*/
release_sock(sk);
return copied;
err_out:
release_sock(sk);
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);
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,
char __user *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 (get_user(val, (int __user *)optval))
return -EINVAL;
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;
len = min_t(unsigned int, len, sizeof(int));
if (len < 0)
return -EINVAL;
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
* POLLHUP
*/
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);
spin_lock_bh(&mux->rx_lock);
kcm_rcv_ready(kcm);
spin_unlock_bh(&mux->rx_lock);
}
static void kcm_rx_msg_timeout(unsigned long arg)
{
struct kcm_psock *psock = (struct kcm_psock *)arg;
/* Message assembly timed out */
KCM_STATS_INCR(psock->stats.rx_msg_timeouts);
kcm_abort_rx_psock(psock, ETIMEDOUT, NULL);
}
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;
if (csock->ops->family != PF_INET &&
csock->ops->family != PF_INET6)
return -EINVAL;
csk = csock->sk;
if (!csk)
return -EINVAL;
/* Only support TCP for now */
if (csk->sk_protocol != IPPROTO_TCP)
return -EINVAL;
psock = kmem_cache_zalloc(kcm_psockp, GFP_KERNEL);
if (!psock)
return -ENOMEM;
psock->mux = mux;
psock->sk = csk;
psock->bpf_prog = prog;
setup_timer(&psock->rx_msg_timer, kcm_rx_msg_timeout,
(unsigned long)psock);
INIT_WORK(&psock->rx_work, psock_rx_work);
INIT_DELAYED_WORK(&psock->rx_delayed_work, psock_rx_delayed_work);
sock_hold(csk);
write_lock_bh(&csk->sk_callback_lock);
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_tcp_data_ready;
csk->sk_write_space = psock_tcp_write_space;
csk->sk_state_change = psock_tcp_state_change;
write_unlock_bh(&csk->sk_callback_lock);
/* 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 */
queue_work(kcm_wq, &psock->rx_work);
return 0;
}
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:
fput(csock->file);
return err;
}
static void kcm_unattach(struct kcm_psock *psock)
{
struct sock *csk = psock->sk;
struct kcm_mux *mux = psock->mux;
/* 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;
psock->rx_stopped = 1;
if (WARN_ON(psock->rx_kcm)) {
write_unlock_bh(&csk->sk_callback_lock);
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);
del_timer_sync(&psock->rx_msg_timer);
cancel_work_sync(&psock->rx_work);
cancel_delayed_work_sync(&psock->rx_delayed_work);
bpf_prog_put(psock->bpf_prog);
kfree_skb(psock->rx_skb_head);
psock->rx_skb_head = NULL;
spin_lock_bh(&mux->lock);
aggregate_psock_stats(&psock->stats, &mux->aggregate_psock_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);
}
}
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);
kcm_unattach(psock);
err = 0;
goto out;
}
spin_unlock_bh(&mux->lock);
out:
fput(csock->file);
return err;
}
static struct proto kcm_proto = {
.name = "KCM",
.owner = THIS_MODULE,
.obj_size = sizeof(struct kcm_sock),
};
/* Clone a kcm socket. */
static int kcm_clone(struct socket *osock, struct kcm_clone *info,
struct socket **newsockp)
{
struct socket *newsock;
struct sock *newsk;
struct file *newfile;
int err, newfd;
err = -ENFILE;
newsock = sock_alloc();
if (!newsock)
goto out;
newsock->type = osock->type;
newsock->ops = osock->ops;
__module_get(newsock->ops->owner);
newfd = get_unused_fd_flags(0);
if (unlikely(newfd < 0)) {
err = newfd;
goto out_fd_fail;
}
newfile = sock_alloc_file(newsock, 0, osock->sk->sk_prot_creator->name);
if (unlikely(IS_ERR(newfile))) {
err = PTR_ERR(newfile);
goto out_sock_alloc_fail;
}
newsk = sk_alloc(sock_net(osock->sk), PF_KCM, GFP_KERNEL,
&kcm_proto, true);
if (!newsk) {
err = -ENOMEM;
goto out_sk_alloc_fail;
}
sock_init_data(newsock, newsk);
init_kcm_sock(kcm_sk(newsk), kcm_sk(osock->sk)->mux);
fd_install(newfd, newfile);
*newsockp = newsock;
info->fd = newfd;
return 0;
out_sk_alloc_fail:
fput(newfile);
out_sock_alloc_fail:
put_unused_fd(newfd);
out_fd_fail:
sock_release(newsock);
out:
return err;
}
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)))
err = -EFAULT;
err = kcm_attach_ioctl(sock, &info);
break;
}
case SIOCKCMUNATTACH: {
struct kcm_unattach info;
if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
err = -EFAULT;
err = kcm_unattach_ioctl(sock, &info);
break;
}
case SIOCKCMCLONE: {
struct kcm_clone info;
struct socket *newsock = NULL;
if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
err = -EFAULT;
err = kcm_clone(sock, &info, &newsock);
if (!err) {
if (copy_to_user((void __user *)arg, &info,
sizeof(info))) {
err = -EFAULT;
sock_release(newsock);
}
}
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);
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);
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;
sock_orphan(sk);
kfree_skb(kcm->seq_skb);
lock_sock(sk);
/* 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);
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,
.sendpage = kcm_sendpage,
};
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,
.sendpage = kcm_sendpage,
.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 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));
}
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_create("kcm_mux_cache",
sizeof(struct kcm_mux), 0,
SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
if (!kcm_muxp)
goto fail;
kcm_psockp = kmem_cache_create("kcm_psock_cache",
sizeof(struct kcm_psock), 0,
SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
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 = sock_register(&kcm_family_ops);
if (err)
goto sock_register_fail;
err = register_pernet_device(&kcm_net_ops);
if (err)
goto net_ops_fail;
err = kcm_proc_init();
if (err)
goto proc_init_fail;
return 0;
proc_init_fail:
unregister_pernet_device(&kcm_net_ops);
net_ops_fail:
sock_unregister(PF_KCM);
sock_register_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();
unregister_pernet_device(&kcm_net_ops);
sock_unregister(PF_KCM);
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_ALIAS_NETPROTO(PF_KCM);
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