net: add context-aware Dialer methods DialTCP, DialUDP, DialIP, DialUnix

Fixes #49097

Author: moredure

src/net/iprawsock.go

@@ -209,11 +209,28 @@ func newIPConn(fd *netFD) *IPConn { return &IPConn{conn{fd}} }
 // If the IP field of raddr is nil or an unspecified IP address, the
 // local system is assumed.
 func DialIP(network string, laddr, raddr *IPAddr) (*IPConn, error) {
+	return DialIPContext(context.Background(), network, laddr, raddr)
+}
+
+// DialIPContext acts like DialIP but connects using
+// the provided context.
+//
+// The provided Context must be non-nil.
+//
+// The network must be an IP network name; see func Dial for details.
+//
+// If laddr is nil, a local address is automatically chosen.
+// If the IP field of raddr is nil or an unspecified IP address, the
+// local system is assumed.
+func DialIPContext(ctx context.Context, network string, laddr, raddr *IPAddr) (*IPConn, error) {
+	if ctx == nil {
+		panic("nil context")
+	}
 	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.dialIP(context.Background(), laddr, raddr)
+	c, err := sd.dialIP(ctx, laddr, raddr)
 	if err != nil {
 		return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err}
 	}

src/net/tcpsock.go

@@ -231,6 +231,23 @@ func newTCPConn(fd *netFD) *TCPConn {
 // If the IP field of raddr is nil or an unspecified IP address, the
 // local system is assumed.
 func DialTCP(network string, laddr, raddr *TCPAddr) (*TCPConn, error) {
+	return DialTCPContext(context.Background(), network, laddr, raddr)
+}
+
+// DialTCPContext acts like DialTCP but connects using
+// the provided context.
+//
+// The provided Context must be non-nil.
+//
+// The network must be a TCP network name; see func Dial for details.
+//
+// If laddr is nil, a local address is automatically chosen.
+// If the IP field of raddr is nil or an unspecified IP address, the
+// local system is assumed.
+func DialTCPContext(ctx context.Context, network string, laddr, raddr *TCPAddr) (*TCPConn, error) {
+	if ctx == nil {
+		panic("nil context")
+	}
 	switch network {
 	case "tcp", "tcp4", "tcp6":
 	default:
@@ -240,7 +257,7 @@ func DialTCP(network string, laddr, raddr *TCPAddr) (*TCPConn, error) {
 		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)
+	c, err := sd.dialTCP(ctx, laddr, raddr)
 	if err != nil {
 		return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err}
 	}

src/net/udpsock.go

@@ -284,6 +284,23 @@ func newUDPConn(fd *netFD) *UDPConn { return &UDPConn{conn{fd}} }
 // If the IP field of raddr is nil or an unspecified IP address, the
 // local system is assumed.
 func DialUDP(network string, laddr, raddr *UDPAddr) (*UDPConn, error) {
+	return DialUDPContext(context.Background(), network, laddr, raddr)
+}
+
+// DialUDPContext acts like DialUDP but connects using
+// the provided context.
+//
+// The provided Context must be non-nil.
+//
+// The network must be a UDP network name; see func Dial for details.
+//
+// If laddr is nil, a local address is automatically chosen.
+// If the IP field of raddr is nil or an unspecified IP address, the
+// local system is assumed.
+func DialUDPContext(ctx context.Context, network string, laddr, raddr *UDPAddr) (*UDPConn, error) {
+	if ctx == nil {
+		panic("nil context")
+	}
 	switch network {
 	case "udp", "udp4", "udp6":
 	default:
@@ -293,7 +310,7 @@ func DialUDP(network string, laddr, raddr *UDPAddr) (*UDPConn, error) {
 		return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: nil, Err: errMissingAddress}
 	}
 	sd := &sysDialer{network: network, address: raddr.String()}
-	c, err := sd.dialUDP(context.Background(), laddr, raddr)
+	c, err := sd.dialUDP(ctx, laddr, raddr)
 	if err != nil {
 		return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err}
 	}

src/net/unixsock.go

@@ -201,13 +201,29 @@ func newUnixConn(fd *netFD) *UnixConn { return &UnixConn{conn{fd}} }
 // If laddr is non-nil, it is used as the local address for the
 // connection.
 func DialUnix(network string, laddr, raddr *UnixAddr) (*UnixConn, error) {
+	return DialUnixContext(context.Background(), network, laddr, raddr)
+}
+
+// DialUnixContext acts like DialUnix but connects using
+// the provided context.
+//
+// The provided Context must be non-nil.
+//
+// The network must be a Unix network name; see func Dial for details.
+//
+// If laddr is non-nil, it is used as the local address for the
+// connection.
+func DialUnixContext(ctx context.Context, network string, laddr, raddr *UnixAddr) (*UnixConn, error) {
+	if ctx == nil {
+		panic("nil context")
+	}
 	switch network {
 	case "unix", "unixgram", "unixpacket":
 	default:
 		return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: UnknownNetworkError(network)}
 	}
 	sd := &sysDialer{network: network, address: raddr.String()}
-	c, err := sd.dialUnix(context.Background(), laddr, raddr)
+	c, err := sd.dialUnix(ctx, laddr, raddr)
 	if err != nil {
 		return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err}
 	}