v4.19.13 snapshot.
diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
new file mode 100644
index 0000000..571d824
--- /dev/null
+++ b/net/kcm/kcmsock.c
@@ -0,0 +1,2106 @@
+/*
+ * Kernel Connection Multiplexor
+ *
+ * Copyright (c) 2016 Tom Herbert <tom@herbertland.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ */
+
+#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 <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>
+
+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;
+ csk->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);
+ 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;
+ 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);
+ 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);
+}
+
+/* Lower sock lock held */
+static void psock_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 (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;
+
+ return (*prog->bpf_func)(skb, prog->insnsi);
+}
+
+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)
+{
+ 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;
+ }
+
+ 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;
+ }
+
+ 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);
+ 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 strp_msg *stm;
+ 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 */
+
+ 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);
+ skb_unlink(skb, &sk->sk_receive_queue);
+ kfree_skb(skb);
+ }
+ }
+
+out:
+ release_sock(sk);
+
+ 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);
+ long timeo;
+ struct strp_msg *stm;
+ 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 */
+
+ 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.
+ */
+
+ 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
+ * 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);
+
+ 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;
+
+ err = strp_init(&psock->strp, csk, &cb);
+ if (err) {
+ kmem_cache_free(kcm_psockp, psock);
+ goto out;
+ }
+
+ write_lock_bh(&csk->sk_callback_lock);
+
+ /* Check if sk_user_data is aready 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);
+ strp_stop(&psock->strp);
+ strp_done(&psock->strp);
+ kmem_cache_free(kcm_psockp, psock);
+ err = -EALREADY;
+ 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:
+ fput(csock->file);
+ 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:
+ 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 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);
+ 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);
+
+ /* 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,
+ .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 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));
+}
+
+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);