}
		if err := setKeepAliveCount(c.fd, config.Count); err != nil {
			return &OpError{Op: "set", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
		}
	} else if err := setKeepAliveIdleAndIntervalAndCount(c.fd, config.Idle, config.Interval, config.Count); err != nil {
		return &OpError{Op: "set", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
	}

	return nil

	}
	return n, addr, err
}

// ReadFrom implements the [PacketConn] ReadFrom method.
func (c *UnixConn) ReadFrom(b []byte) (int, Addr, error) {
	if !c.ok() {
		return 0, nil, syscall.EINVAL
	}
	n, addr, err := c.readFrom(b)
	if err != nil {
		err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
	}
	if addr == nil {
		return n, nil, err
	}

		return nil, mapErr(ctx.Err())
	}
}

func dialPlan9Blocking(ctx context.Context, net string, laddr, raddr Addr) (fd *netFD, err error) {
	if isWildcard(raddr) {
		raddr = toLocal(raddr, net)
	}
	f, dest, proto, name, err := startPlan9(ctx, net, raddr)
	if err != nil {
		return nil, err
	}
	if la := plan9LocalAddr(laddr); la == "" {
		err = hangupCtlWrite(ctx, proto, f, "connect "+dest)
	} else {

		t.Skip("unixgram test")
	}

	addr := testUnixAddr(t)
	laddr, err := ResolveUnixAddr("unixgram", addr)
	if err != nil {
		t.Fatal(err)
	}
	c, err := ListenPacket("unixgram", addr)
	if err != nil {
		t.Fatal(err)
	}
	defer os.Remove(addr)
	defer c.Close()

	testUnixgramWriteConn(t, laddr)
	testUnixgramWritePacketConn(t, laddr)
}

			return ip
		}
	}

	switch addr := addr.(type) {
	case *TCPAddr:
		ip := convertIP(addr.IP)
		if ip == nil || len(ip) == len(addr.IP) {
			return addr
		}
		return &TCPAddr{IP: ip, Port: addr.Port, Zone: addr.Zone}
	case *UDPAddr:
		ip := convertIP(addr.IP)
		if ip == nil || len(ip) == len(addr.IP) {
			return addr
		}
		return &UDPAddr{IP: ip, Port: addr.Port, Zone: addr.Zone}
	default:

	listen, ctl, data *os.File
	laddr, raddr      Addr
	isStream          bool
}

var netdir = "/net" // default network

func newFD(net, name string, listen, ctl, data *os.File, laddr, raddr Addr) (*netFD, error) {
	ret := &netFD{
		net:    net,
		n:      name,
		dir:    netdir + "/" + net + "/" + name,
		listen: listen,
		ctl:    ctl, data: data,
		laddr: laddr,
		raddr: raddr,
	}
	ret.pfd.Destroy = ret.destroy

		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
}

	}
	if raddr == nil {
		return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: nil, Err: errMissingAddress}
	}
	sd := &sysDialer{network: network, address: raddr.String()}
	c, err := sd.dialTCP(context.Background(), laddr, raddr)
	if err != nil {
		return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err}
	}
	return c, nil
}

//go:build !linux

package net

import (
	"context"
)

func (sd *sysDialer) dialMPTCP(ctx context.Context, laddr, raddr *TCPAddr) (*TCPConn, error) {
	return sd.dialTCP(ctx, laddr, raddr)
}

func (sl *sysListener) listenMPTCP(ctx context.Context, laddr *TCPAddr) (*TCPListener, error) {
	return sl.listenTCP(ctx, laddr)
}

func isUsingMultipathTCP(fd *netFD) bool {
	return false

	// immutable until Close
	family      int
	sotype      int
	isConnected bool // handshake completed or use of association with peer
	net         string
	laddr       Addr
	raddr       Addr
}

func (fd *netFD) setAddr(laddr, raddr Addr) {
	fd.laddr = laddr
	fd.raddr = raddr
	runtime.SetFinalizer(fd, (*netFD).Close)
}

func (fd *netFD) Close() error {
	runtime.SetFinalizer(fd, nil)
	return fd.pfd.Close()
}