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174 lines
4.5 KiB
174 lines
4.5 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* Copyright (c) 2021 Cong Wang <[email protected]> */ |
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#include <linux/skmsg.h> |
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#include <linux/bpf.h> |
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#include <net/sock.h> |
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#include <net/af_unix.h> |
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#define unix_sk_has_data(__sk, __psock) \ |
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({ !skb_queue_empty(&__sk->sk_receive_queue) || \ |
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!skb_queue_empty(&__psock->ingress_skb) || \ |
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!list_empty(&__psock->ingress_msg); \ |
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}) |
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static int unix_msg_wait_data(struct sock *sk, struct sk_psock *psock, |
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long timeo) |
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{ |
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DEFINE_WAIT_FUNC(wait, woken_wake_function); |
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struct unix_sock *u = unix_sk(sk); |
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int ret = 0; |
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if (sk->sk_shutdown & RCV_SHUTDOWN) |
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return 1; |
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if (!timeo) |
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return ret; |
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add_wait_queue(sk_sleep(sk), &wait); |
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sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); |
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if (!unix_sk_has_data(sk, psock)) { |
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mutex_unlock(&u->iolock); |
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wait_woken(&wait, TASK_INTERRUPTIBLE, timeo); |
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mutex_lock(&u->iolock); |
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ret = unix_sk_has_data(sk, psock); |
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} |
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sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); |
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remove_wait_queue(sk_sleep(sk), &wait); |
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return ret; |
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} |
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static int __unix_recvmsg(struct sock *sk, struct msghdr *msg, |
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size_t len, int flags) |
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{ |
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if (sk->sk_type == SOCK_DGRAM) |
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return __unix_dgram_recvmsg(sk, msg, len, flags); |
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else |
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return __unix_stream_recvmsg(sk, msg, len, flags); |
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} |
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static int unix_bpf_recvmsg(struct sock *sk, struct msghdr *msg, |
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size_t len, int nonblock, int flags, |
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int *addr_len) |
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{ |
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struct unix_sock *u = unix_sk(sk); |
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struct sk_psock *psock; |
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int copied; |
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psock = sk_psock_get(sk); |
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if (unlikely(!psock)) |
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return __unix_recvmsg(sk, msg, len, flags); |
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mutex_lock(&u->iolock); |
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if (!skb_queue_empty(&sk->sk_receive_queue) && |
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sk_psock_queue_empty(psock)) { |
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mutex_unlock(&u->iolock); |
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sk_psock_put(sk, psock); |
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return __unix_recvmsg(sk, msg, len, flags); |
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} |
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msg_bytes_ready: |
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copied = sk_msg_recvmsg(sk, psock, msg, len, flags); |
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if (!copied) { |
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long timeo; |
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int data; |
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timeo = sock_rcvtimeo(sk, nonblock); |
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data = unix_msg_wait_data(sk, psock, timeo); |
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if (data) { |
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if (!sk_psock_queue_empty(psock)) |
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goto msg_bytes_ready; |
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mutex_unlock(&u->iolock); |
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sk_psock_put(sk, psock); |
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return __unix_recvmsg(sk, msg, len, flags); |
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} |
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copied = -EAGAIN; |
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} |
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mutex_unlock(&u->iolock); |
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sk_psock_put(sk, psock); |
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return copied; |
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} |
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static struct proto *unix_dgram_prot_saved __read_mostly; |
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static DEFINE_SPINLOCK(unix_dgram_prot_lock); |
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static struct proto unix_dgram_bpf_prot; |
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static struct proto *unix_stream_prot_saved __read_mostly; |
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static DEFINE_SPINLOCK(unix_stream_prot_lock); |
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static struct proto unix_stream_bpf_prot; |
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static void unix_dgram_bpf_rebuild_protos(struct proto *prot, const struct proto *base) |
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{ |
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*prot = *base; |
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prot->close = sock_map_close; |
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prot->recvmsg = unix_bpf_recvmsg; |
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} |
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static void unix_stream_bpf_rebuild_protos(struct proto *prot, |
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const struct proto *base) |
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{ |
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*prot = *base; |
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prot->close = sock_map_close; |
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prot->recvmsg = unix_bpf_recvmsg; |
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prot->unhash = sock_map_unhash; |
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} |
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static void unix_dgram_bpf_check_needs_rebuild(struct proto *ops) |
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{ |
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if (unlikely(ops != smp_load_acquire(&unix_dgram_prot_saved))) { |
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spin_lock_bh(&unix_dgram_prot_lock); |
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if (likely(ops != unix_dgram_prot_saved)) { |
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unix_dgram_bpf_rebuild_protos(&unix_dgram_bpf_prot, ops); |
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smp_store_release(&unix_dgram_prot_saved, ops); |
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} |
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spin_unlock_bh(&unix_dgram_prot_lock); |
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} |
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} |
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static void unix_stream_bpf_check_needs_rebuild(struct proto *ops) |
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{ |
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if (unlikely(ops != smp_load_acquire(&unix_stream_prot_saved))) { |
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spin_lock_bh(&unix_stream_prot_lock); |
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if (likely(ops != unix_stream_prot_saved)) { |
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unix_stream_bpf_rebuild_protos(&unix_stream_bpf_prot, ops); |
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smp_store_release(&unix_stream_prot_saved, ops); |
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} |
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spin_unlock_bh(&unix_stream_prot_lock); |
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} |
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} |
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int unix_dgram_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore) |
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{ |
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if (sk->sk_type != SOCK_DGRAM) |
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return -EOPNOTSUPP; |
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if (restore) { |
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sk->sk_write_space = psock->saved_write_space; |
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WRITE_ONCE(sk->sk_prot, psock->sk_proto); |
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return 0; |
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} |
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unix_dgram_bpf_check_needs_rebuild(psock->sk_proto); |
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WRITE_ONCE(sk->sk_prot, &unix_dgram_bpf_prot); |
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return 0; |
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} |
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int unix_stream_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore) |
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{ |
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if (restore) { |
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sk->sk_write_space = psock->saved_write_space; |
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WRITE_ONCE(sk->sk_prot, psock->sk_proto); |
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return 0; |
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} |
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unix_stream_bpf_check_needs_rebuild(psock->sk_proto); |
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WRITE_ONCE(sk->sk_prot, &unix_stream_bpf_prot); |
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return 0; |
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} |
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void __init unix_bpf_build_proto(void) |
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{ |
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unix_dgram_bpf_rebuild_protos(&unix_dgram_bpf_prot, &unix_dgram_proto); |
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unix_stream_bpf_rebuild_protos(&unix_stream_bpf_prot, &unix_stream_proto); |
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}
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