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