libgo/go/syscall/lsf_linux.go

   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, unsafe.Pointer(&p), Socklen_t(unsafe.Sizeof(p)))
  73 }
  74
  75 func DetachLsf(fd int) error {
  76         var dummy int
  77         return setsockopt(fd, SOL_SOCKET, SO_DETACH_FILTER, unsafe.Pointer(&dummy), Socklen_t(unsafe.Sizeof(dummy)))
  78 }