Source file src/pkg/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, 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	}