127 lines
2.7 KiB
Go
127 lines
2.7 KiB
Go
package sys
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import (
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"runtime"
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"syscall"
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"unsafe"
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"github.com/cilium/ebpf/internal/unix"
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)
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// BPF wraps SYS_BPF.
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//
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// Any pointers contained in attr must use the Pointer type from this package.
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func BPF(cmd Cmd, attr unsafe.Pointer, size uintptr) (uintptr, error) {
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for {
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r1, _, errNo := unix.Syscall(unix.SYS_BPF, uintptr(cmd), uintptr(attr), size)
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runtime.KeepAlive(attr)
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// As of ~4.20 the verifier can be interrupted by a signal,
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// and returns EAGAIN in that case.
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if errNo == unix.EAGAIN && cmd == BPF_PROG_LOAD {
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continue
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}
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var err error
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if errNo != 0 {
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err = wrappedErrno{errNo}
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}
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return r1, err
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}
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}
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// Info is implemented by all structs that can be passed to the ObjInfo syscall.
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//
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// MapInfo
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// ProgInfo
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// LinkInfo
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// BtfInfo
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type Info interface {
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info() (unsafe.Pointer, uint32)
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}
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var _ Info = (*MapInfo)(nil)
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func (i *MapInfo) info() (unsafe.Pointer, uint32) {
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return unsafe.Pointer(i), uint32(unsafe.Sizeof(*i))
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}
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var _ Info = (*ProgInfo)(nil)
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func (i *ProgInfo) info() (unsafe.Pointer, uint32) {
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return unsafe.Pointer(i), uint32(unsafe.Sizeof(*i))
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}
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var _ Info = (*LinkInfo)(nil)
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func (i *LinkInfo) info() (unsafe.Pointer, uint32) {
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return unsafe.Pointer(i), uint32(unsafe.Sizeof(*i))
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}
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var _ Info = (*BtfInfo)(nil)
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func (i *BtfInfo) info() (unsafe.Pointer, uint32) {
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return unsafe.Pointer(i), uint32(unsafe.Sizeof(*i))
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}
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// ObjInfo retrieves information about a BPF Fd.
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//
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// info may be one of MapInfo, ProgInfo, LinkInfo and BtfInfo.
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func ObjInfo(fd *FD, info Info) error {
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ptr, len := info.info()
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err := ObjGetInfoByFd(&ObjGetInfoByFdAttr{
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BpfFd: fd.Uint(),
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InfoLen: len,
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Info: NewPointer(ptr),
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})
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runtime.KeepAlive(fd)
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return err
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}
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// BPFObjName is a null-terminated string made up of
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// 'A-Za-z0-9_' characters.
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type ObjName [unix.BPF_OBJ_NAME_LEN]byte
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// NewObjName truncates the result if it is too long.
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func NewObjName(name string) ObjName {
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var result ObjName
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copy(result[:unix.BPF_OBJ_NAME_LEN-1], name)
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return result
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}
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// LinkID uniquely identifies a bpf_link.
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type LinkID uint32
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// BTFID uniquely identifies a BTF blob loaded into the kernel.
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type BTFID uint32
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// wrappedErrno wraps syscall.Errno to prevent direct comparisons with
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// syscall.E* or unix.E* constants.
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//
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// You should never export an error of this type.
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type wrappedErrno struct {
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syscall.Errno
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}
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func (we wrappedErrno) Unwrap() error {
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return we.Errno
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}
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type syscallError struct {
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error
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errno syscall.Errno
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}
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func Error(err error, errno syscall.Errno) error {
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return &syscallError{err, errno}
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}
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func (se *syscallError) Is(target error) bool {
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return target == se.error
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}
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func (se *syscallError) Unwrap() error {
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return se.errno
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}
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