2c4ae3b0a4
Содержимое пина, зафиксированного в go.mod sing-box-lx, одним коммитом без истории. Полная история SagerNet/gvisor — 1.45 ГБ и клонируется в каждой CI-джобе; наша дельта — одна вставка в одну функцию, история для неё не нужна. Module path github.com/sagernet/gvisor сохранён намеренно: на него опирается replace-директива суперпроекта. Патч поверх — отдельным коммитом, чтобы дельта читалась одним git show и переносилась на новый пин копированием. SPECS/TASKS/048-GVISOR_HANDSHAKE_NIL_CRASH
107 lines
2.9 KiB
Go
107 lines
2.9 KiB
Go
// Copyright 2022 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//go:build amd64 || arm64
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// +build amd64 arm64
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package xdp
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import (
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"fmt"
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"github.com/sagernet/gvisor/pkg/sync"
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"golang.org/x/sys/unix"
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)
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// TODO(b/240191988): There's some kind of memory corruption bug that occurs
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// occasionally. This occurred even before TX was supported.
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// TODO(b/240191988): We can hold locks for less time if we accept a more
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// obtuse API. For example, CompletionQueue.FreeAll doesn't need to hold a
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// mutex for its entire duration.
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// UMEM is the shared memory area that the kernel and userspace put packets in.
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type UMEM struct {
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// mem is the mmap'd area shared with the kernel.
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mem []byte
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// sockfd is the underlying AF_XDP socket.
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sockfd uint32
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// frameMask masks the lower bits of an address to get the frame's
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// address.
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frameMask uint64
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// mu protects frameAddresses and nFreeFrames.
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mu sync.Mutex
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// frameAddresses is a stack of available frame addresses.
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// +checklocks:mu
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frameAddresses []uint64
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// nFreeFrames is the number of frames available and is used to index
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// into frameAddresses.
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// +checklocks:mu
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nFreeFrames uint32
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}
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// SockFD returns the underlying AF_XDP socket FD.
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func (um *UMEM) SockFD() uint32 {
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return um.sockfd
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}
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// Lock locks the UMEM.
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//
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// +checklocksacquire:um.mu
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func (um *UMEM) Lock() {
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um.mu.Lock()
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}
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// Unlock unlocks the UMEM.
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//
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// +checklocksrelease:um.mu
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func (um *UMEM) Unlock() {
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um.mu.Unlock()
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}
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// FreeFrame returns the frame containing addr to the set of free frames.
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//
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// The UMEM must be locked during the call to FreeFrame.
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//
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// +checklocks:um.mu
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func (um *UMEM) FreeFrame(addr uint64) {
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um.frameAddresses[um.nFreeFrames] = addr
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um.nFreeFrames++
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}
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// AllocFrame returns the address of a frame that can be enqueued to the fill
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// or TX queue. It will panic if there are no frames left, so callers must call
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// it no more than the number of buffers reserved via TXQueue.Reserve().
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//
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// The UMEM must be locked during the call to AllocFrame.
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//
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// +checklocks:um.mu
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func (um *UMEM) AllocFrame() uint64 {
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um.nFreeFrames--
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return um.frameAddresses[um.nFreeFrames] & um.frameMask
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}
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// Get gets the bytes of the packet pointed to by desc.
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func (um *UMEM) Get(desc unix.XDPDesc) []byte {
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end := desc.Addr + uint64(desc.Len)
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if desc.Addr&um.frameMask != (end-1)&um.frameMask {
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panic(fmt.Sprintf("UMEM (%+v) access crosses frame boundaries: %+v", um, desc))
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}
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return um.mem[desc.Addr:end]
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}
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