123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228 |
- // Copyright 2009 The Go Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style
- // license that can be found in the LICENSE file.
- //go:build aix || darwin || dragonfly || freebsd || hurd || (js && wasm) || linux || netbsd || openbsd || solaris || windows
- package net
- import (
- "context"
- "internal/poll"
- "net/netip"
- "runtime"
- "syscall"
- )
- // probe probes IPv4, IPv6 and IPv4-mapped IPv6 communication
- // capabilities which are controlled by the IPV6_V6ONLY socket option
- // and kernel configuration.
- //
- // Should we try to use the IPv4 socket interface if we're only
- // dealing with IPv4 sockets? As long as the host system understands
- // IPv4-mapped IPv6, it's okay to pass IPv4-mapped IPv6 addresses to
- // the IPv6 interface. That simplifies our code and is most
- // general. Unfortunately, we need to run on kernels built without
- // IPv6 support too. So probe the kernel to figure it out.
- func (p *ipStackCapabilities) probe() {
- s, err := sysSocket(syscall.AF_INET, syscall.SOCK_STREAM, syscall.IPPROTO_TCP)
- switch err {
- case syscall.EAFNOSUPPORT, syscall.EPROTONOSUPPORT:
- case nil:
- poll.CloseFunc(s)
- p.ipv4Enabled = true
- }
- var probes = []struct {
- laddr TCPAddr
- value int
- }{
- // IPv6 communication capability
- {laddr: TCPAddr{IP: ParseIP("::1")}, value: 1},
- // IPv4-mapped IPv6 address communication capability
- {laddr: TCPAddr{IP: IPv4(127, 0, 0, 1)}, value: 0},
- }
- switch runtime.GOOS {
- case "dragonfly", "openbsd":
- // The latest DragonFly BSD and OpenBSD kernels don't
- // support IPV6_V6ONLY=0. They always return an error
- // and we don't need to probe the capability.
- probes = probes[:1]
- }
- for i := range probes {
- s, err := sysSocket(syscall.AF_INET6, syscall.SOCK_STREAM, syscall.IPPROTO_TCP)
- if err != nil {
- continue
- }
- defer poll.CloseFunc(s)
- syscall.SetsockoptInt(s, syscall.IPPROTO_IPV6, syscall.IPV6_V6ONLY, probes[i].value)
- sa, err := probes[i].laddr.sockaddr(syscall.AF_INET6)
- if err != nil {
- continue
- }
- if err := syscall.Bind(s, sa); err != nil {
- continue
- }
- if i == 0 {
- p.ipv6Enabled = true
- } else {
- p.ipv4MappedIPv6Enabled = true
- }
- }
- }
- // favoriteAddrFamily returns the appropriate address family for the
- // given network, laddr, raddr and mode.
- //
- // If mode indicates "listen" and laddr is a wildcard, we assume that
- // the user wants to make a passive-open connection with a wildcard
- // address family, both AF_INET and AF_INET6, and a wildcard address
- // like the following:
- //
- // - A listen for a wildcard communication domain, "tcp" or
- // "udp", with a wildcard address: If the platform supports
- // both IPv6 and IPv4-mapped IPv6 communication capabilities,
- // or does not support IPv4, we use a dual stack, AF_INET6 and
- // IPV6_V6ONLY=0, wildcard address listen. The dual stack
- // wildcard address listen may fall back to an IPv6-only,
- // AF_INET6 and IPV6_V6ONLY=1, wildcard address listen.
- // Otherwise we prefer an IPv4-only, AF_INET, wildcard address
- // listen.
- //
- // - A listen for a wildcard communication domain, "tcp" or
- // "udp", with an IPv4 wildcard address: same as above.
- //
- // - A listen for a wildcard communication domain, "tcp" or
- // "udp", with an IPv6 wildcard address: same as above.
- //
- // - A listen for an IPv4 communication domain, "tcp4" or "udp4",
- // with an IPv4 wildcard address: We use an IPv4-only, AF_INET,
- // wildcard address listen.
- //
- // - A listen for an IPv6 communication domain, "tcp6" or "udp6",
- // with an IPv6 wildcard address: We use an IPv6-only, AF_INET6
- // and IPV6_V6ONLY=1, wildcard address listen.
- //
- // Otherwise guess: If the addresses are IPv4 then returns AF_INET,
- // or else returns AF_INET6. It also returns a boolean value what
- // designates IPV6_V6ONLY option.
- //
- // Note that the latest DragonFly BSD and OpenBSD kernels allow
- // neither "net.inet6.ip6.v6only=1" change nor IPPROTO_IPV6 level
- // IPV6_V6ONLY socket option setting.
- func favoriteAddrFamily(network string, laddr, raddr sockaddr, mode string) (family int, ipv6only bool) {
- switch network[len(network)-1] {
- case '4':
- return syscall.AF_INET, false
- case '6':
- return syscall.AF_INET6, true
- }
- if mode == "listen" && (laddr == nil || laddr.isWildcard()) {
- if supportsIPv4map() || !supportsIPv4() {
- return syscall.AF_INET6, false
- }
- if laddr == nil {
- return syscall.AF_INET, false
- }
- return laddr.family(), false
- }
- if (laddr == nil || laddr.family() == syscall.AF_INET) &&
- (raddr == nil || raddr.family() == syscall.AF_INET) {
- return syscall.AF_INET, false
- }
- return syscall.AF_INET6, false
- }
- func internetSocket(ctx context.Context, net string, laddr, raddr sockaddr, sotype, proto int, mode string, ctrlFn func(string, string, syscall.RawConn) error) (fd *netFD, err error) {
- if (runtime.GOOS == "aix" || runtime.GOOS == "windows" || runtime.GOOS == "openbsd") && mode == "dial" && raddr.isWildcard() {
- raddr = raddr.toLocal(net)
- }
- family, ipv6only := favoriteAddrFamily(net, laddr, raddr, mode)
- return socket(ctx, net, family, sotype, proto, ipv6only, laddr, raddr, ctrlFn)
- }
- func ipToSockaddrInet4(ip IP, port int) (syscall.SockaddrInet4, error) {
- if len(ip) == 0 {
- ip = IPv4zero
- }
- ip4 := ip.To4()
- if ip4 == nil {
- return syscall.SockaddrInet4{}, &AddrError{Err: "non-IPv4 address", Addr: ip.String()}
- }
- sa := syscall.SockaddrInet4{Port: port}
- copy(sa.Addr[:], ip4)
- return sa, nil
- }
- func ipToSockaddrInet6(ip IP, port int, zone string) (syscall.SockaddrInet6, error) {
- // In general, an IP wildcard address, which is either
- // "0.0.0.0" or "::", means the entire IP addressing
- // space. For some historical reason, it is used to
- // specify "any available address" on some operations
- // of IP node.
- //
- // When the IP node supports IPv4-mapped IPv6 address,
- // we allow a listener to listen to the wildcard
- // address of both IP addressing spaces by specifying
- // IPv6 wildcard address.
- if len(ip) == 0 || ip.Equal(IPv4zero) {
- ip = IPv6zero
- }
- // We accept any IPv6 address including IPv4-mapped
- // IPv6 address.
- ip6 := ip.To16()
- if ip6 == nil {
- return syscall.SockaddrInet6{}, &AddrError{Err: "non-IPv6 address", Addr: ip.String()}
- }
- sa := syscall.SockaddrInet6{Port: port, ZoneId: uint32(zoneCache.index(zone))}
- copy(sa.Addr[:], ip6)
- return sa, nil
- }
- func ipToSockaddr(family int, ip IP, port int, zone string) (syscall.Sockaddr, error) {
- switch family {
- case syscall.AF_INET:
- sa, err := ipToSockaddrInet4(ip, port)
- if err != nil {
- return nil, err
- }
- return &sa, nil
- case syscall.AF_INET6:
- sa, err := ipToSockaddrInet6(ip, port, zone)
- if err != nil {
- return nil, err
- }
- return &sa, nil
- }
- return nil, &AddrError{Err: "invalid address family", Addr: ip.String()}
- }
- func addrPortToSockaddrInet4(ap netip.AddrPort) (syscall.SockaddrInet4, error) {
- // ipToSockaddrInet4 has special handling here for zero length slices.
- // We do not, because netip has no concept of a generic zero IP address.
- addr := ap.Addr()
- if !addr.Is4() {
- return syscall.SockaddrInet4{}, &AddrError{Err: "non-IPv4 address", Addr: addr.String()}
- }
- sa := syscall.SockaddrInet4{
- Addr: addr.As4(),
- Port: int(ap.Port()),
- }
- return sa, nil
- }
- func addrPortToSockaddrInet6(ap netip.AddrPort) (syscall.SockaddrInet6, error) {
- // ipToSockaddrInet6 has special handling here for zero length slices.
- // We do not, because netip has no concept of a generic zero IP address.
- addr := ap.Addr()
- if !addr.Is6() {
- return syscall.SockaddrInet6{}, &AddrError{Err: "non-IPv6 address", Addr: addr.String()}
- }
- sa := syscall.SockaddrInet6{
- Addr: addr.As16(),
- Port: int(ap.Port()),
- ZoneId: uint32(zoneCache.index(addr.Zone())),
- }
- return sa, nil
- }
|