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// Copyright (C) 2016 Nippon Telegraph and Telephone Corporation.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
// implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// +build linux
package server
import (
"net"
"os"
"syscall"
"unsafe"
)
const (
tcpMD5SIG = 14 // TCP MD5 Signature (RFC2385)
ipv6MinHopCount = 73 // Generalized TTL Security Mechanism (RFC5082)
)
type tcpmd5sig struct {
ss_family uint16
ss [126]byte
// padding the struct
_ uint16
keylen uint16
// padding the struct
_ uint32
key [80]byte
}
func buildTcpMD5Sig(address, 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 setTCPMD5SigSockopt(l *net.TCPListener, address string, key string) error {
t, err := buildTcpMD5Sig(address, key)
if err != nil {
return err
}
b := *(*[unsafe.Sizeof(t)]byte)(unsafe.Pointer(&t))
sc, err := l.SyscallConn()
if err != nil {
return err
}
return setsockOptString(sc, syscall.IPPROTO_TCP, tcpMD5SIG, string(b[:]))
}
func setBindToDevSockopt(sc syscall.RawConn, device string) error {
return setsockOptString(sc, syscall.SOL_SOCKET, syscall.SO_BINDTODEVICE, device)
}
func setTCPTTLSockopt(conn *net.TCPConn, ttl int) error {
family := extractFamilyFromTCPConn(conn)
sc, err := conn.SyscallConn()
if err != nil {
return err
}
return setsockoptIpTtl(sc, family, ttl)
}
func setTCPMinTTLSockopt(conn *net.TCPConn, ttl int) error {
family := extractFamilyFromTCPConn(conn)
sc, err := conn.SyscallConn()
if err != nil {
return err
}
level := syscall.IPPROTO_IP
name := syscall.IP_MINTTL
if family == syscall.AF_INET6 {
level = syscall.IPPROTO_IPV6
name = ipv6MinHopCount
}
return setsockOptInt(sc, level, name, ttl)
}
func dialerControl(network, address string, c syscall.RawConn, ttl, minTtl uint8, password string, bindInterface string) error {
family := syscall.AF_INET
raddr, _ := net.ResolveTCPAddr("tcp", address)
if raddr.IP.To4() == nil {
family = syscall.AF_INET6
}
var sockerr error
if password != "" {
addr, _, _ := net.SplitHostPort(address)
t, err := buildTcpMD5Sig(addr, password)
if err != nil {
return err
}
b := *(*[unsafe.Sizeof(t)]byte)(unsafe.Pointer(&t))
if err := c.Control(func(fd uintptr) {
sockerr = os.NewSyscallError("setsockopt", syscall.SetsockoptString(int(fd), syscall.IPPROTO_TCP, tcpMD5SIG, string(b[:])))
}); err != nil {
return err
}
if sockerr != nil {
return sockerr
}
}
if ttl != 0 {
if err := c.Control(func(fd uintptr) {
level := syscall.IPPROTO_IP
name := syscall.IP_TTL
if family == syscall.AF_INET6 {
level = syscall.IPPROTO_IPV6
name = syscall.IPV6_UNICAST_HOPS
}
sockerr = os.NewSyscallError("setsockopt", syscall.SetsockoptInt(int(fd), level, name, int(ttl)))
}); err != nil {
return err
}
if sockerr != nil {
return sockerr
}
}
if minTtl != 0 {
if err := c.Control(func(fd uintptr) {
level := syscall.IPPROTO_IP
name := syscall.IP_MINTTL
if family == syscall.AF_INET6 {
level = syscall.IPPROTO_IPV6
name = ipv6MinHopCount
}
sockerr = os.NewSyscallError("setsockopt", syscall.SetsockoptInt(int(fd), level, name, int(minTtl)))
}); err != nil {
return err
}
if sockerr != nil {
return sockerr
}
}
if bindInterface != "" {
if err := setBindToDevSockopt(c, bindInterface); err != nil {
return err
}
}
return nil
}
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