github.com/graybobo/golang.org-package-offline-cache@v0.0.0-20200626051047-6608995c132f/x/sys/unix/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 unix 8 9 import ( 10 "syscall" 11 "unsafe" 12 ) 13 14 func LsfStmt(code, k int) *SockFilter { 15 return &SockFilter{Code: uint16(code), K: uint32(k)} 16 } 17 18 func LsfJump(code, k, jt, jf int) *SockFilter { 19 return &SockFilter{Code: uint16(code), Jt: uint8(jt), Jf: uint8(jf), K: uint32(k)} 20 } 21 22 func LsfSocket(ifindex, proto int) (int, error) { 23 var lsall SockaddrLinklayer 24 s, e := Socket(AF_PACKET, SOCK_RAW, proto) 25 if e != nil { 26 return 0, e 27 } 28 p := (*[2]byte)(unsafe.Pointer(&lsall.Protocol)) 29 p[0] = byte(proto >> 8) 30 p[1] = byte(proto) 31 lsall.Ifindex = ifindex 32 e = Bind(s, &lsall) 33 if e != nil { 34 Close(s) 35 return 0, e 36 } 37 return s, nil 38 } 39 40 type iflags struct { 41 name [IFNAMSIZ]byte 42 flags uint16 43 } 44 45 func SetLsfPromisc(name string, m bool) error { 46 s, e := Socket(AF_INET, SOCK_DGRAM, 0) 47 if e != nil { 48 return e 49 } 50 defer Close(s) 51 var ifl iflags 52 copy(ifl.name[:], []byte(name)) 53 _, _, ep := Syscall(SYS_IOCTL, uintptr(s), SIOCGIFFLAGS, uintptr(unsafe.Pointer(&ifl))) 54 if ep != 0 { 55 return syscall.Errno(ep) 56 } 57 if m { 58 ifl.flags |= uint16(IFF_PROMISC) 59 } else { 60 ifl.flags &= ^uint16(IFF_PROMISC) 61 } 62 _, _, ep = Syscall(SYS_IOCTL, uintptr(s), SIOCSIFFLAGS, uintptr(unsafe.Pointer(&ifl))) 63 if ep != 0 { 64 return syscall.Errno(ep) 65 } 66 return nil 67 } 68 69 func AttachLsf(fd int, i []SockFilter) error { 70 var p SockFprog 71 p.Len = uint16(len(i)) 72 p.Filter = (*SockFilter)(unsafe.Pointer(&i[0])) 73 return setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, unsafe.Pointer(&p), unsafe.Sizeof(p)) 74 } 75 76 func DetachLsf(fd int) error { 77 var dummy int 78 return setsockopt(fd, SOL_SOCKET, SO_DETACH_FILTER, unsafe.Pointer(&dummy), unsafe.Sizeof(dummy)) 79 }