github.com/spotify/syslog-redirector-golang@v0.0.0-20140320174030-4859f03d829a/src/pkg/syscall/lsf_linux.go (about)

     1  // Copyright 2011 The Go Authors.  All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Linux socket filter
     6  
     7  package syscall
     8  
     9  import (
    10  	"unsafe"
    11  )
    12  
    13  func LsfStmt(code, k int) *SockFilter {
    14  	return &SockFilter{Code: uint16(code), K: uint32(k)}
    15  }
    16  
    17  func LsfJump(code, k, jt, jf int) *SockFilter {
    18  	return &SockFilter{Code: uint16(code), Jt: uint8(jt), Jf: uint8(jf), K: uint32(k)}
    19  }
    20  
    21  func LsfSocket(ifindex, proto int) (int, error) {
    22  	var lsall SockaddrLinklayer
    23  	s, e := Socket(AF_PACKET, SOCK_RAW, proto)
    24  	if e != nil {
    25  		return 0, e
    26  	}
    27  	p := (*[2]byte)(unsafe.Pointer(&lsall.Protocol))
    28  	p[0] = byte(proto >> 8)
    29  	p[1] = byte(proto)
    30  	lsall.Ifindex = ifindex
    31  	e = Bind(s, &lsall)
    32  	if e != nil {
    33  		Close(s)
    34  		return 0, e
    35  	}
    36  	return s, nil
    37  }
    38  
    39  type iflags struct {
    40  	name  [IFNAMSIZ]byte
    41  	flags uint16
    42  }
    43  
    44  func SetLsfPromisc(name string, m bool) error {
    45  	s, e := Socket(AF_INET, SOCK_DGRAM, 0)
    46  	if e != nil {
    47  		return e
    48  	}
    49  	defer Close(s)
    50  	var ifl iflags
    51  	copy(ifl.name[:], []byte(name))
    52  	_, _, ep := Syscall(SYS_IOCTL, uintptr(s), SIOCGIFFLAGS, uintptr(unsafe.Pointer(&ifl)))
    53  	if ep != 0 {
    54  		return Errno(ep)
    55  	}
    56  	if m {
    57  		ifl.flags |= uint16(IFF_PROMISC)
    58  	} else {
    59  		ifl.flags &= ^uint16(IFF_PROMISC)
    60  	}
    61  	_, _, ep = Syscall(SYS_IOCTL, uintptr(s), SIOCSIFFLAGS, uintptr(unsafe.Pointer(&ifl)))
    62  	if ep != 0 {
    63  		return Errno(ep)
    64  	}
    65  	return nil
    66  }
    67  
    68  func AttachLsf(fd int, i []SockFilter) error {
    69  	var p SockFprog
    70  	p.Len = uint16(len(i))
    71  	p.Filter = (*SockFilter)(unsafe.Pointer(&i[0]))
    72  	return setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, uintptr(unsafe.Pointer(&p)), unsafe.Sizeof(p))
    73  }
    74  
    75  func DetachLsf(fd int) error {
    76  	var dummy int
    77  	return setsockopt(fd, SOL_SOCKET, SO_DETACH_FILTER, uintptr(unsafe.Pointer(&dummy)), unsafe.Sizeof(dummy))
    78  }