/usr/share/gocode/src/github.com/vishvananda/netlink/socket_linux.go is in golang-github-vishvananda-netlink-dev 0.0~git20170407.0.1e86b2b-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 | package netlink
import (
"errors"
"fmt"
"net"
"syscall"
"github.com/vishvananda/netlink/nl"
)
const (
sizeofSocketID = 0x30
sizeofSocketRequest = sizeofSocketID + 0x8
sizeofSocket = sizeofSocketID + 0x18
)
type socketRequest struct {
Family uint8
Protocol uint8
Ext uint8
pad uint8
States uint32
ID SocketID
}
type writeBuffer struct {
Bytes []byte
pos int
}
func (b *writeBuffer) Write(c byte) {
b.Bytes[b.pos] = c
b.pos++
}
func (b *writeBuffer) Next(n int) []byte {
s := b.Bytes[b.pos : b.pos+n]
b.pos += n
return s
}
func (r *socketRequest) Serialize() []byte {
b := writeBuffer{Bytes: make([]byte, sizeofSocketRequest)}
b.Write(r.Family)
b.Write(r.Protocol)
b.Write(r.Ext)
b.Write(r.pad)
native.PutUint32(b.Next(4), r.States)
networkOrder.PutUint16(b.Next(2), r.ID.SourcePort)
networkOrder.PutUint16(b.Next(2), r.ID.DestinationPort)
copy(b.Next(4), r.ID.Source.To4())
b.Next(12)
copy(b.Next(4), r.ID.Destination.To4())
b.Next(12)
native.PutUint32(b.Next(4), r.ID.Interface)
native.PutUint32(b.Next(4), r.ID.Cookie[0])
native.PutUint32(b.Next(4), r.ID.Cookie[1])
return b.Bytes
}
func (r *socketRequest) Len() int { return sizeofSocketRequest }
type readBuffer struct {
Bytes []byte
pos int
}
func (b *readBuffer) Read() byte {
c := b.Bytes[b.pos]
b.pos++
return c
}
func (b *readBuffer) Next(n int) []byte {
s := b.Bytes[b.pos : b.pos+n]
b.pos += n
return s
}
func (s *Socket) deserialize(b []byte) error {
if len(b) < sizeofSocket {
return fmt.Errorf("socket data short read (%d); want %d", len(b), sizeofSocket)
}
rb := readBuffer{Bytes: b}
s.Family = rb.Read()
s.State = rb.Read()
s.Timer = rb.Read()
s.Retrans = rb.Read()
s.ID.SourcePort = networkOrder.Uint16(rb.Next(2))
s.ID.DestinationPort = networkOrder.Uint16(rb.Next(2))
s.ID.Source = net.IPv4(rb.Read(), rb.Read(), rb.Read(), rb.Read())
rb.Next(12)
s.ID.Destination = net.IPv4(rb.Read(), rb.Read(), rb.Read(), rb.Read())
rb.Next(12)
s.ID.Interface = native.Uint32(rb.Next(4))
s.ID.Cookie[0] = native.Uint32(rb.Next(4))
s.ID.Cookie[1] = native.Uint32(rb.Next(4))
s.Expires = native.Uint32(rb.Next(4))
s.RQueue = native.Uint32(rb.Next(4))
s.WQueue = native.Uint32(rb.Next(4))
s.UID = native.Uint32(rb.Next(4))
s.INode = native.Uint32(rb.Next(4))
return nil
}
// SocketGet returns the Socket identified by its local and remote addresses.
func SocketGet(local, remote net.Addr) (*Socket, error) {
localTCP, ok := local.(*net.TCPAddr)
if !ok {
return nil, ErrNotImplemented
}
remoteTCP, ok := remote.(*net.TCPAddr)
if !ok {
return nil, ErrNotImplemented
}
localIP := localTCP.IP.To4()
if localIP == nil {
return nil, ErrNotImplemented
}
remoteIP := remoteTCP.IP.To4()
if remoteIP == nil {
return nil, ErrNotImplemented
}
s, err := nl.Subscribe(syscall.NETLINK_INET_DIAG)
if err != nil {
return nil, err
}
defer s.Close()
req := nl.NewNetlinkRequest(nl.SOCK_DIAG_BY_FAMILY, 0)
req.AddData(&socketRequest{
Family: syscall.AF_INET,
Protocol: syscall.IPPROTO_TCP,
ID: SocketID{
SourcePort: uint16(localTCP.Port),
DestinationPort: uint16(remoteTCP.Port),
Source: localIP,
Destination: remoteIP,
Cookie: [2]uint32{nl.TCPDIAG_NOCOOKIE, nl.TCPDIAG_NOCOOKIE},
},
})
s.Send(req)
msgs, err := s.Receive()
if err != nil {
return nil, err
}
if len(msgs) == 0 {
return nil, errors.New("no message nor error from netlink")
}
if len(msgs) > 2 {
return nil, fmt.Errorf("multiple (%d) matching sockets", len(msgs))
}
sock := &Socket{}
if err := sock.deserialize(msgs[0].Data); err != nil {
return nil, err
}
return sock, nil
}
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