// 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. package net import ( "context" "errors" "net/netip" "os" "syscall" ) func (c *UDPConn) readFrom(b []byte, addr *UDPAddr) (int, *UDPAddr, error) { buf := make([]byte, udpHeaderSize+len(b)) m, err := c.fd.Read(buf) if err != nil { return 0, nil, err } if m < udpHeaderSize { return 0, nil, errors.New("short read reading UDP header") } buf = buf[:m] h, buf := unmarshalUDPHeader(buf) n := copy(b, buf) *addr = UDPAddr{IP: h.raddr, Port: int(h.rport)} return n, addr, nil } func (c *UDPConn) readFromAddrPort(b []byte) (int, netip.AddrPort, error) { // TODO: optimize. The equivalent code on posix is alloc-free. buf := make([]byte, udpHeaderSize+len(b)) m, err := c.fd.Read(buf) if err != nil { return 0, netip.AddrPort{}, err } if m < udpHeaderSize { return 0, netip.AddrPort{}, errors.New("short read reading UDP header") } buf = buf[:m] h, buf := unmarshalUDPHeader(buf) n := copy(b, buf) ip, _ := netip.AddrFromSlice(h.raddr) addr := netip.AddrPortFrom(ip, h.rport) return n, addr, nil } func (c *UDPConn) readMsg(b, oob []byte) (n, oobn, flags int, addr netip.AddrPort, err error) { return 0, 0, 0, netip.AddrPort{}, syscall.EPLAN9 } func (c *UDPConn) writeTo(b []byte, addr *UDPAddr) (int, error) { if addr == nil { return 0, errMissingAddress } h := new(udpHeader) h.raddr = addr.IP.To16() h.laddr = c.fd.laddr.(*UDPAddr).IP.To16() h.ifcaddr = IPv6zero // ignored (receive only) h.rport = uint16(addr.Port) h.lport = uint16(c.fd.laddr.(*UDPAddr).Port) buf := make([]byte, udpHeaderSize+len(b)) i := copy(buf, h.Bytes()) copy(buf[i:], b) if _, err := c.fd.Write(buf); err != nil { return 0, err } return len(b), nil } func (c *UDPConn) writeToAddrPort(b []byte, addr netip.AddrPort) (int, error) { return c.writeTo(b, UDPAddrFromAddrPort(addr)) // TODO: optimize instead of allocating } func (c *UDPConn) writeMsg(b, oob []byte, addr *UDPAddr) (n, oobn int, err error) { return 0, 0, syscall.EPLAN9 } func (c *UDPConn) writeMsgAddrPort(b, oob []byte, addr netip.AddrPort) (n, oobn int, err error) { return 0, 0, syscall.EPLAN9 } func (sd *sysDialer) dialUDP(ctx context.Context, laddr, raddr *UDPAddr) (*UDPConn, error) { fd, err := dialPlan9(ctx, sd.network, laddr, raddr) if err != nil { return nil, err } return newUDPConn(fd), nil } const udpHeaderSize = 16*3 + 2*2 type udpHeader struct { raddr, laddr, ifcaddr IP rport, lport uint16 } func (h *udpHeader) Bytes() []byte { b := make([]byte, udpHeaderSize) i := 0 i += copy(b[i:i+16], h.raddr) i += copy(b[i:i+16], h.laddr) i += copy(b[i:i+16], h.ifcaddr) b[i], b[i+1], i = byte(h.rport>>8), byte(h.rport), i+2 b[i], b[i+1], i = byte(h.lport>>8), byte(h.lport), i+2 return b } func unmarshalUDPHeader(b []byte) (*udpHeader, []byte) { h := new(udpHeader) h.raddr, b = IP(b[:16]), b[16:] h.laddr, b = IP(b[:16]), b[16:] h.ifcaddr, b = IP(b[:16]), b[16:] h.rport, b = uint16(b[0])<<8|uint16(b[1]), b[2:] h.lport, b = uint16(b[0])<<8|uint16(b[1]), b[2:] return h, b } func (sl *sysListener) listenUDP(ctx context.Context, laddr *UDPAddr) (*UDPConn, error) { l, err := listenPlan9(ctx, sl.network, laddr) if err != nil { return nil, err } _, err = l.ctl.WriteString("headers") if err != nil { return nil, err } l.data, err = os.OpenFile(l.dir+"/data", os.O_RDWR, 0) if err != nil { return nil, err } fd, err := l.netFD() return newUDPConn(fd), err } func (sl *sysListener) listenMulticastUDP(ctx context.Context, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) { // Plan 9 does not like announce command with a multicast address, // so do not specify an IP address when listening. l, err := listenPlan9(ctx, sl.network, &UDPAddr{IP: nil, Port: gaddr.Port, Zone: gaddr.Zone}) if err != nil { return nil, err } _, err = l.ctl.WriteString("headers") if err != nil { return nil, err } var addrs []Addr if ifi != nil { addrs, err = ifi.Addrs() if err != nil { return nil, err } } else { addrs, err = InterfaceAddrs() if err != nil { return nil, err } } have4 := gaddr.IP.To4() != nil for _, addr := range addrs { if ipnet, ok := addr.(*IPNet); ok && (ipnet.IP.To4() != nil) == have4 { _, err = l.ctl.WriteString("addmulti " + ipnet.IP.String() + " " + gaddr.IP.String()) if err != nil { return nil, &OpError{Op: "addmulti", Net: "", Source: nil, Addr: ipnet, Err: err} } } } l.data, err = os.OpenFile(l.dir+"/data", os.O_RDWR, 0) if err != nil { return nil, err } fd, err := l.netFD() if err != nil { return nil, err } return newUDPConn(fd), nil }