/
syscall_unix.go
53 lines (48 loc) · 1.25 KB
/
syscall_unix.go
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
//go:build aix || darwin || dragonfly || freebsd || (js && wasm) || linux || nacl || netbsd || openbsd || solaris
package tlsmiddlebox
//
// syscall utilities for dialerTTLWrapperConn
//
import (
"net"
"syscall"
)
// SetTTL sets the IP TTL field for the underlying net.TCPConn
func (c *dialerTTLWrapperConn) SetTTL(ttl int) error {
conn := c.Conn
tcpConn, ok := conn.(*net.TCPConn)
if !ok {
return errInvalidConnWrapper
}
rawConn, err := tcpConn.SyscallConn()
if err != nil {
return err
}
rawErr := rawConn.Control(func(fd uintptr) {
err = syscall.SetsockoptInt(int(fd), syscall.IPPROTO_IP, syscall.IP_TTL, ttl)
})
// The syscall err is given a higher priority and returned early if non-nil
if err != nil {
return err
}
return rawErr
}
// GetSoErr fetches the SO_ERROR value to look for soft ICMP errors in TCP
func (c *dialerTTLWrapperConn) GetSoErr() (errno int, err error) {
conn := c.Conn
tcpConn, ok := conn.(*net.TCPConn)
if !ok {
return 0, errInvalidConnWrapper
}
rawConn, err := tcpConn.SyscallConn()
if err != nil {
return 0, errInvalidConnWrapper
}
rawErr := rawConn.Control(func(fd uintptr) {
errno, err = syscall.GetsockoptInt(int(fd), syscall.SOL_SOCKET, syscall.SO_ERROR)
})
if rawErr != nil {
return 0, rawErr
}
return
}