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afinetrawsocket.go
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/
afinetrawsocket.go
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// +build linux
package afinetrawsocket
import (
"fmt"
"syscall"
"go.aporeto.io/trireme-lib/controller/pkg/packet"
)
type socketv4 struct {
fd int
insock *syscall.SockaddrInet4
}
type socketv6 struct {
fd int
insock *syscall.SockaddrInet6
}
type rawsocket struct {
insockv4 *socketv4
insockv6 *socketv6
}
const (
// RawSocketMark is the mark asserted on all packet sent out of this socket
RawSocketMark = 0x63
// NetworkRawSocketMark is the mark on packet egressing
//the raw socket coming in from network
NetworkRawSocketMark = 0x40000063
//ApplicationRawSocketMark is the mark on packet egressing
//the raw socket coming from application
ApplicationRawSocketMark = 0x40000062
)
// SocketWriter interface exposes an interface to write and close sockets
type SocketWriter interface {
WriteSocket(buf []byte, version packet.IPver) error
}
// CreateSocket returns a handle to SocketWriter interface
func CreateSocket(mark int, deviceName string) (SocketWriter, error) {
createSocketv4 := func() (*socketv4, error) {
fd, _ := syscall.Socket(syscall.AF_INET, syscall.SOCK_RAW, syscall.IPPROTO_UDP)
if err := syscall.SetsockoptInt(fd, syscall.SOL_SOCKET, syscall.SO_MARK, mark); err != nil {
syscall.Close(fd) // nolint
return nil, fmt.Errorf("Received error %s while setting socket Option SO_MARK", err)
}
if err := syscall.SetsockoptInt(fd, syscall.IPPROTO_IP, syscall.IP_HDRINCL, 0); err != nil {
syscall.Close(fd) // nolint
return nil, fmt.Errorf("Received error %s while setting socket Option IP_HDRINCL", err)
}
if err := syscall.SetsockoptInt(fd, syscall.IPPROTO_IP, syscall.IP_MTU_DISCOVER, syscall.IP_PMTUDISC_DONT); err != nil {
syscall.Close(fd) // nolint
return nil, fmt.Errorf("Received error %s while setting socket Option IP_PMTUDISC_DONT", err)
}
return &socketv4{
fd: fd,
insock: &syscall.SockaddrInet4{
Port: 0,
},
}, nil
}
createSocketv6 := func() (*socketv6, error) {
fd, _ := syscall.Socket(syscall.AF_INET6, syscall.SOCK_RAW, syscall.IPPROTO_UDP)
if err := syscall.SetsockoptInt(fd, syscall.SOL_SOCKET, syscall.SO_MARK, mark); err != nil {
syscall.Close(fd) // nolint
return nil, fmt.Errorf("Received error %s while setting socket Option SO_MARK", err)
}
if err := syscall.SetsockoptInt(fd, syscall.IPPROTO_IPV6, syscall.IP_HDRINCL, 0); err != nil {
syscall.Close(fd) // nolint
return nil, fmt.Errorf("Received error %s while setting socket Option IP_HDRINCL", err)
}
if err := syscall.SetsockoptInt(fd, syscall.IPPROTO_IPV6, syscall.IPV6_MTU_DISCOVER, syscall.IPV6_PMTUDISC_DONT); err != nil {
syscall.Close(fd) // nolint
return nil, fmt.Errorf("Received error %s while setting socket Option IP_PMTUDISC_DONT ipv6", err)
}
return &socketv6{
fd: fd,
insock: &syscall.SockaddrInet6{
Port: 0,
},
}, nil
}
sockv4, err := createSocketv4()
if err != nil {
return nil, err
}
sockv6, err := createSocketv6()
if err != nil {
return nil, err
}
return &rawsocket{
insockv4: sockv4,
insockv6: sockv6,
}, nil
}
func (sock *rawsocket) WriteSocket(buf []byte, version packet.IPver) error {
// copy the dest addr
if version == packet.V4 {
copy(sock.insockv4.insock.Addr[:], buf[16:20])
if err := syscall.Sendto(sock.insockv4.fd, buf[20:], 0, sock.insockv4.insock); err != nil {
return fmt.Errorf("received error %s while sending to socket", err)
}
} else {
copy(sock.insockv6.insock.Addr[:], buf[24:40])
if err := syscall.Sendto(sock.insockv6.fd, buf[40:], 0, sock.insockv6.insock); err != nil {
return fmt.Errorf("received error %s while sending to socket", err)
}
}
return nil
}