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package server
import (
"net"
"os"
"reflect"
"strings"
"syscall"
"unsafe"
)
const (
TCP_MD5SIG = 14
)
type tcpmd5sig struct {
ss_family uint16
ss [126]byte
pad1 uint16
keylen uint16
pad2 uint32
key [80]byte
}
func buildTcpMD5Sig(address string, key string) (tcpmd5sig, error) {
t := tcpmd5sig{}
addr := net.ParseIP(address)
if addr.To4() != nil {
t.ss_family = syscall.AF_INET
copy(t.ss[2:], addr.To4())
} else {
t.ss_family = syscall.AF_INET6
copy(t.ss[6:], addr.To16())
}
t.keylen = uint16(len(key))
copy(t.key[0:], []byte(key))
return t, nil
}
func SetTcpMD5SigSockopts(fd int, address string, key string) error {
t, _ := buildTcpMD5Sig(address, key)
_, _, e := syscall.Syscall6(syscall.SYS_SETSOCKOPT, uintptr(fd),
uintptr(syscall.IPPROTO_TCP), uintptr(TCP_MD5SIG),
uintptr(unsafe.Pointer(&t)), unsafe.Sizeof(t), 0)
return e
}
func TCPConnToFd(tcp *net.TCPConn) int {
n := reflect.ValueOf(*tcp)
conn := n.FieldByName("conn")
fd := conn.FieldByName("fd")
p := reflect.Indirect(fd)
sysfd := p.FieldByName("sysfd")
return int(sysfd.Int())
}
func SetTcpTTLSockopts(conn *net.TCPConn, ttl int) error {
level := syscall.IPPROTO_IP
name := syscall.IP_TTL
if strings.Contains(conn.RemoteAddr().String(), "[") {
level = syscall.IPPROTO_IPV6
name = syscall.IPV6_UNICAST_HOPS
}
return os.NewSyscallError("setsockopt", syscall.SetsockoptInt(TCPConnToFd(conn), level, name, ttl))
}
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