250 lines
7.9 KiB
Go
250 lines
7.9 KiB
Go
// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build darwin dragonfly freebsd linux nacl netbsd openbsd solaris windows
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package net
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import (
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"syscall"
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"time"
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)
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// BUG(mikio): On every POSIX platform, reads from the "ip4" network
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// using the ReadFrom or ReadFromIP method might not return a complete
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// IPv4 packet, including its header, even if there is space
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// available. This can occur even in cases where Read or ReadMsgIP
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// could return a complete packet. For this reason, it is recommended
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// that you do not uses these methods if it is important to receive a
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// full packet.
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//
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// The Go 1 compatibility guidelines make it impossible for us to
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// change the behavior of these methods; use Read or ReadMsgIP
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// instead.
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func sockaddrToIP(sa syscall.Sockaddr) Addr {
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switch sa := sa.(type) {
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case *syscall.SockaddrInet4:
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return &IPAddr{IP: sa.Addr[0:]}
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case *syscall.SockaddrInet6:
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return &IPAddr{IP: sa.Addr[0:], Zone: zoneToString(int(sa.ZoneId))}
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}
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return nil
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}
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func (a *IPAddr) family() int {
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if a == nil || len(a.IP) <= IPv4len {
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return syscall.AF_INET
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}
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if a.IP.To4() != nil {
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return syscall.AF_INET
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}
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return syscall.AF_INET6
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}
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func (a *IPAddr) sockaddr(family int) (syscall.Sockaddr, error) {
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if a == nil {
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return nil, nil
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}
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return ipToSockaddr(family, a.IP, 0, a.Zone)
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}
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// IPConn is the implementation of the Conn and PacketConn interfaces
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// for IP network connections.
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type IPConn struct {
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conn
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}
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func newIPConn(fd *netFD) *IPConn { return &IPConn{conn{fd}} }
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// ReadFromIP reads an IP packet from c, copying the payload into b.
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// It returns the number of bytes copied into b and the return address
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// that was on the packet.
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//
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// ReadFromIP can be made to time out and return an error with
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// Timeout() == true after a fixed time limit; see SetDeadline and
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// SetReadDeadline.
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func (c *IPConn) ReadFromIP(b []byte) (int, *IPAddr, error) {
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if !c.ok() {
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return 0, nil, syscall.EINVAL
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}
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// TODO(cw,rsc): consider using readv if we know the family
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// type to avoid the header trim/copy
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var addr *IPAddr
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n, sa, err := c.fd.readFrom(b)
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switch sa := sa.(type) {
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case *syscall.SockaddrInet4:
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addr = &IPAddr{IP: sa.Addr[0:]}
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n = stripIPv4Header(n, b)
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case *syscall.SockaddrInet6:
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addr = &IPAddr{IP: sa.Addr[0:], Zone: zoneToString(int(sa.ZoneId))}
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}
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if err != nil {
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err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
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}
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return n, addr, err
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}
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func stripIPv4Header(n int, b []byte) int {
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if len(b) < 20 {
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return n
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}
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l := int(b[0]&0x0f) << 2
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if 20 > l || l > len(b) {
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return n
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}
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if b[0]>>4 != 4 {
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return n
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}
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copy(b, b[l:])
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return n - l
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}
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// ReadFrom implements the PacketConn ReadFrom method.
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func (c *IPConn) ReadFrom(b []byte) (int, Addr, error) {
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if !c.ok() {
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return 0, nil, syscall.EINVAL
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}
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n, addr, err := c.ReadFromIP(b)
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if addr == nil {
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return n, nil, err
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}
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return n, addr, err
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}
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// ReadMsgIP reads a packet from c, copying the payload into b and the
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// associated out-of-band data into oob. It returns the number of
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// bytes copied into b, the number of bytes copied into oob, the flags
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// that were set on the packet and the source address of the packet.
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func (c *IPConn) ReadMsgIP(b, oob []byte) (n, oobn, flags int, addr *IPAddr, err error) {
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if !c.ok() {
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return 0, 0, 0, nil, syscall.EINVAL
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}
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var sa syscall.Sockaddr
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n, oobn, flags, sa, err = c.fd.readMsg(b, oob)
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switch sa := sa.(type) {
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case *syscall.SockaddrInet4:
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addr = &IPAddr{IP: sa.Addr[0:]}
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case *syscall.SockaddrInet6:
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addr = &IPAddr{IP: sa.Addr[0:], Zone: zoneToString(int(sa.ZoneId))}
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}
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if err != nil {
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err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
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}
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return
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}
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// WriteToIP writes an IP packet to addr via c, copying the payload
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// from b.
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//
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// WriteToIP can be made to time out and return an error with
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// Timeout() == true after a fixed time limit; see SetDeadline and
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// SetWriteDeadline. On packet-oriented connections, write timeouts
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// are rare.
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func (c *IPConn) WriteToIP(b []byte, addr *IPAddr) (int, error) {
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if !c.ok() {
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return 0, syscall.EINVAL
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}
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if c.fd.isConnected {
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return 0, &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: ErrWriteToConnected}
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}
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if addr == nil {
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return 0, &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: nil, Err: errMissingAddress}
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}
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sa, err := addr.sockaddr(c.fd.family)
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if err != nil {
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return 0, &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
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}
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n, err := c.fd.writeTo(b, sa)
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if err != nil {
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err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
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}
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return n, err
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}
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// WriteTo implements the PacketConn WriteTo method.
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func (c *IPConn) WriteTo(b []byte, addr Addr) (int, error) {
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if !c.ok() {
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return 0, syscall.EINVAL
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}
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a, ok := addr.(*IPAddr)
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if !ok {
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return 0, &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr, Err: syscall.EINVAL}
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}
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return c.WriteToIP(b, a)
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}
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// WriteMsgIP writes a packet to addr via c, copying the payload from
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// b and the associated out-of-band data from oob. It returns the
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// number of payload and out-of-band bytes written.
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func (c *IPConn) WriteMsgIP(b, oob []byte, addr *IPAddr) (n, oobn int, err error) {
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if !c.ok() {
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return 0, 0, syscall.EINVAL
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}
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if c.fd.isConnected {
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return 0, 0, &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: ErrWriteToConnected}
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}
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if addr == nil {
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return 0, 0, &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: nil, Err: errMissingAddress}
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}
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var sa syscall.Sockaddr
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sa, err = addr.sockaddr(c.fd.family)
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if err != nil {
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return 0, 0, &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
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}
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n, oobn, err = c.fd.writeMsg(b, oob, sa)
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if err != nil {
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err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
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}
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return
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}
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// DialIP connects to the remote address raddr on the network protocol
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// netProto, which must be "ip", "ip4", or "ip6" followed by a colon
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// and a protocol number or name.
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func DialIP(netProto string, laddr, raddr *IPAddr) (*IPConn, error) {
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return dialIP(netProto, laddr, raddr, noDeadline)
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}
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func dialIP(netProto string, laddr, raddr *IPAddr, deadline time.Time) (*IPConn, error) {
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net, proto, err := parseNetwork(netProto)
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if err != nil {
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return nil, &OpError{Op: "dial", Net: netProto, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err}
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}
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switch net {
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case "ip", "ip4", "ip6":
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default:
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return nil, &OpError{Op: "dial", Net: netProto, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: UnknownNetworkError(netProto)}
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}
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if raddr == nil {
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return nil, &OpError{Op: "dial", Net: netProto, Source: laddr.opAddr(), Addr: nil, Err: errMissingAddress}
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}
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fd, err := internetSocket(net, laddr, raddr, deadline, syscall.SOCK_RAW, proto, "dial", noCancel)
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if err != nil {
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return nil, &OpError{Op: "dial", Net: netProto, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err}
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}
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return newIPConn(fd), nil
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}
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// ListenIP listens for incoming IP packets addressed to the local
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// address laddr. The returned connection's ReadFrom and WriteTo
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// methods can be used to receive and send IP packets with per-packet
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// addressing.
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func ListenIP(netProto string, laddr *IPAddr) (*IPConn, error) {
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net, proto, err := parseNetwork(netProto)
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if err != nil {
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return nil, &OpError{Op: "listen", Net: netProto, Source: nil, Addr: laddr.opAddr(), Err: err}
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}
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switch net {
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case "ip", "ip4", "ip6":
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default:
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return nil, &OpError{Op: "listen", Net: netProto, Source: nil, Addr: laddr.opAddr(), Err: UnknownNetworkError(netProto)}
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}
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fd, err := internetSocket(net, laddr, nil, noDeadline, syscall.SOCK_RAW, proto, "listen", noCancel)
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if err != nil {
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return nil, &OpError{Op: "listen", Net: netProto, Source: nil, Addr: laddr.opAddr(), Err: err}
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}
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return newIPConn(fd), nil
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}
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