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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Linux socket filter
package syscall
import (
"unsafe"
)
func LsfStmt(code, k int) *SockFilter {
return &SockFilter{Code: uint16(code), K: uint32(k)}
}
func LsfJump(code, k, jt, jf int) *SockFilter {
return &SockFilter{Code: uint16(code), Jt: uint8(jt), Jf: uint8(jf), K: uint32(k)}
}
func LsfSocket(ifindex, proto int) (int, error) {
var lsall SockaddrLinklayer
s, e := Socket(AF_PACKET, SOCK_RAW, proto)
if e != nil {
return 0, e
}
p := (*[2]byte)(unsafe.Pointer(&lsall.Protocol))
p[0] = byte(proto >> 8)
p[1] = byte(proto)
lsall.Ifindex = ifindex
e = Bind(s, &lsall)
if e != nil {
Close(s)
return 0, e
}
return s, nil
}
type iflags struct {
name [IFNAMSIZ]byte
flags uint16
}
func SetLsfPromisc(name string, m bool) error {
s, e := Socket(AF_INET, SOCK_DGRAM, 0)
if e != nil {
return e
}
defer Close(s)
var ifl iflags
copy(ifl.name[:], []byte(name))
_, _, ep := Syscall(SYS_IOCTL, uintptr(s), SIOCGIFFLAGS, uintptr(unsafe.Pointer(&ifl)))
if ep != 0 {
return Errno(ep)
}
if m {
ifl.flags |= uint16(IFF_PROMISC)
} else {
ifl.flags &= ^uint16(IFF_PROMISC)
}
_, _, ep = Syscall(SYS_IOCTL, uintptr(s), SIOCSIFFLAGS, uintptr(unsafe.Pointer(&ifl)))
if ep != 0 {
return Errno(ep)
}
return nil
}
func AttachLsf(fd int, i []SockFilter) error {
var p SockFprog
p.Len = uint16(len(i))
p.Filter = (*SockFilter)(unsafe.Pointer(&i[0]))
return setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, unsafe.Pointer(&p), unsafe.Sizeof(p))
}
func DetachLsf(fd int) error {
var dummy int
return setsockopt(fd, SOL_SOCKET, SO_DETACH_FILTER, unsafe.Pointer(&dummy), unsafe.Sizeof(dummy))
}
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