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// Copyright 2010 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.
// +build darwin dragonfly freebsd linux netbsd openbsd windows
package net
import (
"syscall"
"time"
)
// BUG(mikio): On every POSIX platform, reads from the "ip4" network
// using the ReadFrom or ReadFromIP method might not return a complete
// IPv4 packet, including its header, even if there is space
// available. This can occur even in cases where Read or ReadMsgIP
// could return a complete packet. For this reason, it is recommended
// that you do not uses these methods if it is important to receive a
// full packet.
//
// The Go 1 compatibliity guidelines make it impossible for us to
// change the behavior of these methods; use Read or ReadMsgIP
// instead.
func sockaddrToIP(sa syscall.Sockaddr) Addr {
switch sa := sa.(type) {
case *syscall.SockaddrInet4:
return &IPAddr{IP: sa.Addr[0:]}
case *syscall.SockaddrInet6:
return &IPAddr{IP: sa.Addr[0:], Zone: zoneToString(int(sa.ZoneId))}
}
return nil
}
func (a *IPAddr) family() int {
if a == nil || len(a.IP) <= IPv4len {
return syscall.AF_INET
}
if a.IP.To4() != nil {
return syscall.AF_INET
}
return syscall.AF_INET6
}
func (a *IPAddr) isWildcard() bool {
if a == nil || a.IP == nil {
return true
}
return a.IP.IsUnspecified()
}
func (a *IPAddr) sockaddr(family int) (syscall.Sockaddr, error) {
if a == nil {
return nil, nil
}
return ipToSockaddr(family, a.IP, 0, a.Zone)
}
// IPConn is the implementation of the Conn and PacketConn interfaces
// for IP network connections.
type IPConn struct {
conn
}
func newIPConn(fd *netFD) *IPConn { return &IPConn{conn{fd}} }
// ReadFromIP reads an IP packet from c, copying the payload into b.
// It returns the number of bytes copied into b and the return address
// that was on the packet.
//
// ReadFromIP can be made to time out and return an error with
// Timeout() == true after a fixed time limit; see SetDeadline and
// SetReadDeadline.
func (c *IPConn) ReadFromIP(b []byte) (int, *IPAddr, error) {
if !c.ok() {
return 0, nil, syscall.EINVAL
}
// TODO(cw,rsc): consider using readv if we know the family
// type to avoid the header trim/copy
var addr *IPAddr
n, sa, err := c.fd.ReadFrom(b)
switch sa := sa.(type) {
case *syscall.SockaddrInet4:
addr = &IPAddr{IP: sa.Addr[0:]}
if len(b) >= IPv4len { // discard ipv4 header
hsize := (int(b[0]) & 0xf) * 4
copy(b, b[hsize:])
n -= hsize
}
case *syscall.SockaddrInet6:
addr = &IPAddr{IP: sa.Addr[0:], Zone: zoneToString(int(sa.ZoneId))}
}
return n, addr, err
}
// ReadFrom implements the PacketConn ReadFrom method.
func (c *IPConn) ReadFrom(b []byte) (int, Addr, error) {
if !c.ok() {
return 0, nil, syscall.EINVAL
}
n, addr, err := c.ReadFromIP(b)
return n, addr.toAddr(), err
}
// ReadMsgIP reads a packet from c, copying the payload into b and the
// associated out-of-band data into oob. It returns the number of
// bytes copied into b, the number of bytes copied into oob, the flags
// that were set on the packet and the source address of the packet.
func (c *IPConn) ReadMsgIP(b, oob []byte) (n, oobn, flags int, addr *IPAddr, err error) {
if !c.ok() {
return 0, 0, 0, nil, syscall.EINVAL
}
var sa syscall.Sockaddr
n, oobn, flags, sa, err = c.fd.ReadMsg(b, oob)
switch sa := sa.(type) {
case *syscall.SockaddrInet4:
addr = &IPAddr{IP: sa.Addr[0:]}
case *syscall.SockaddrInet6:
addr = &IPAddr{IP: sa.Addr[0:], Zone: zoneToString(int(sa.ZoneId))}
}
return
}
// WriteToIP writes an IP packet to addr via c, copying the payload
// from b.
//
// WriteToIP can be made to time out and return an error with
// Timeout() == true after a fixed time limit; see SetDeadline and
// SetWriteDeadline. On packet-oriented connections, write timeouts
// are rare.
func (c *IPConn) WriteToIP(b []byte, addr *IPAddr) (int, error) {
if !c.ok() {
return 0, syscall.EINVAL
}
if addr == nil {
return 0, &OpError{Op: "write", Net: c.fd.net, Addr: nil, Err: errMissingAddress}
}
sa, err := addr.sockaddr(c.fd.family)
if err != nil {
return 0, &OpError{"write", c.fd.net, addr, err}
}
return c.fd.WriteTo(b, sa)
}
// WriteTo implements the PacketConn WriteTo method.
func (c *IPConn) WriteTo(b []byte, addr Addr) (int, error) {
if !c.ok() {
return 0, syscall.EINVAL
}
a, ok := addr.(*IPAddr)
if !ok {
return 0, &OpError{"write", c.fd.net, addr, syscall.EINVAL}
}
return c.WriteToIP(b, a)
}
// WriteMsgIP writes a packet to addr via c, copying the payload from
// b and the associated out-of-band data from oob. It returns the
// number of payload and out-of-band bytes written.
func (c *IPConn) WriteMsgIP(b, oob []byte, addr *IPAddr) (n, oobn int, err error) {
if !c.ok() {
return 0, 0, syscall.EINVAL
}
if addr == nil {
return 0, 0, &OpError{Op: "write", Net: c.fd.net, Addr: nil, Err: errMissingAddress}
}
sa, err := addr.sockaddr(c.fd.family)
if err != nil {
return 0, 0, &OpError{"write", c.fd.net, addr, err}
}
return c.fd.WriteMsg(b, oob, sa)
}
// DialIP connects to the remote address raddr on the network protocol
// netProto, which must be "ip", "ip4", or "ip6" followed by a colon
// and a protocol number or name.
func DialIP(netProto string, laddr, raddr *IPAddr) (*IPConn, error) {
return dialIP(netProto, laddr, raddr, noDeadline)
}
func dialIP(netProto string, laddr, raddr *IPAddr, deadline time.Time) (*IPConn, error) {
net, proto, err := parseNetwork(netProto)
if err != nil {
return nil, &OpError{Op: "dial", Net: netProto, Addr: raddr, Err: err}
}
switch net {
case "ip", "ip4", "ip6":
default:
return nil, &OpError{Op: "dial", Net: netProto, Addr: raddr, Err: UnknownNetworkError(netProto)}
}
if raddr == nil {
return nil, &OpError{Op: "dial", Net: netProto, Addr: nil, Err: errMissingAddress}
}
fd, err := internetSocket(net, laddr, raddr, deadline, syscall.SOCK_RAW, proto, "dial", sockaddrToIP)
if err != nil {
return nil, &OpError{Op: "dial", Net: netProto, Addr: raddr, Err: err}
}
return newIPConn(fd), nil
}
// ListenIP listens for incoming IP packets addressed to the local
// address laddr. The returned connection's ReadFrom and WriteTo
// methods can be used to receive and send IP packets with per-packet
// addressing.
func ListenIP(netProto string, laddr *IPAddr) (*IPConn, error) {
net, proto, err := parseNetwork(netProto)
if err != nil {
return nil, &OpError{Op: "dial", Net: netProto, Addr: laddr, Err: err}
}
switch net {
case "ip", "ip4", "ip6":
default:
return nil, &OpError{Op: "listen", Net: netProto, Addr: laddr, Err: UnknownNetworkError(netProto)}
}
fd, err := internetSocket(net, laddr, nil, noDeadline, syscall.SOCK_RAW, proto, "listen", sockaddrToIP)
if err != nil {
return nil, &OpError{Op: "listen", Net: netProto, Addr: laddr, Err: err}
}
return newIPConn(fd), nil
}
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