Use caddy's certmagic library for extensible/robust ACME handling (#14177)

* use certmagic for more extensible/robust ACME cert handling

* accept TOS based on config option

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: Lauris BH <lauris@nix.lv>

vendor/golang.org/x/net/ipv4/batch.go

@@ -0,0 +1,194 @@
+// Copyright 2017 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 ipv4
+
+import (
+	"net"
+	"runtime"
+
+	"golang.org/x/net/internal/socket"
+)
+
+// BUG(mikio): On Windows, the ReadBatch and WriteBatch methods of
+// PacketConn are not implemented.
+
+// BUG(mikio): On Windows, the ReadBatch and WriteBatch methods of
+// RawConn are not implemented.
+
+// A Message represents an IO message.
+//
+//	type Message struct {
+//		Buffers [][]byte
+//		OOB     []byte
+//		Addr    net.Addr
+//		N       int
+//		NN      int
+//		Flags   int
+//	}
+//
+// The Buffers fields represents a list of contiguous buffers, which
+// can be used for vectored IO, for example, putting a header and a
+// payload in each slice.
+// When writing, the Buffers field must contain at least one byte to
+// write.
+// When reading, the Buffers field will always contain a byte to read.
+//
+// The OOB field contains protocol-specific control or miscellaneous
+// ancillary data known as out-of-band data.
+// It can be nil when not required.
+//
+// The Addr field specifies a destination address when writing.
+// It can be nil when the underlying protocol of the endpoint uses
+// connection-oriented communication.
+// After a successful read, it may contain the source address on the
+// received packet.
+//
+// The N field indicates the number of bytes read or written from/to
+// Buffers.
+//
+// The NN field indicates the number of bytes read or written from/to
+// OOB.
+//
+// The Flags field contains protocol-specific information on the
+// received message.
+type Message = socket.Message
+
+// ReadBatch reads a batch of messages.
+//
+// The provided flags is a set of platform-dependent flags, such as
+// syscall.MSG_PEEK.
+//
+// On a successful read it returns the number of messages received, up
+// to len(ms).
+//
+// On Linux, a batch read will be optimized.
+// On other platforms, this method will read only a single message.
+//
+// Unlike the ReadFrom method, it doesn't strip the IPv4 header
+// followed by option headers from the received IPv4 datagram when the
+// underlying transport is net.IPConn. Each Buffers field of Message
+// must be large enough to accommodate an IPv4 header and option
+// headers.
+func (c *payloadHandler) ReadBatch(ms []Message, flags int) (int, error) {
+	if !c.ok() {
+		return 0, errInvalidConn
+	}
+	switch runtime.GOOS {
+	case "linux":
+		n, err := c.RecvMsgs([]socket.Message(ms), flags)
+		if err != nil {
+			err = &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err}
+		}
+		return n, err
+	default:
+		n := 1
+		err := c.RecvMsg(&ms[0], flags)
+		if err != nil {
+			n = 0
+			err = &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err}
+		}
+		if compatFreeBSD32 && ms[0].NN > 0 {
+			adjustFreeBSD32(&ms[0])
+		}
+		return n, err
+	}
+}
+
+// WriteBatch writes a batch of messages.
+//
+// The provided flags is a set of platform-dependent flags, such as
+// syscall.MSG_DONTROUTE.
+//
+// It returns the number of messages written on a successful write.
+//
+// On Linux, a batch write will be optimized.
+// On other platforms, this method will write only a single message.
+func (c *payloadHandler) WriteBatch(ms []Message, flags int) (int, error) {
+	if !c.ok() {
+		return 0, errInvalidConn
+	}
+	switch runtime.GOOS {
+	case "linux":
+		n, err := c.SendMsgs([]socket.Message(ms), flags)
+		if err != nil {
+			err = &net.OpError{Op: "write", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err}
+		}
+		return n, err
+	default:
+		n := 1
+		err := c.SendMsg(&ms[0], flags)
+		if err != nil {
+			n = 0
+			err = &net.OpError{Op: "write", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err}
+		}
+		return n, err
+	}
+}
+
+// ReadBatch reads a batch of messages.
+//
+// The provided flags is a set of platform-dependent flags, such as
+// syscall.MSG_PEEK.
+//
+// On a successful read it returns the number of messages received, up
+// to len(ms).
+//
+// On Linux, a batch read will be optimized.
+// On other platforms, this method will read only a single message.
+func (c *packetHandler) ReadBatch(ms []Message, flags int) (int, error) {
+	if !c.ok() {
+		return 0, errInvalidConn
+	}
+	switch runtime.GOOS {
+	case "linux":
+		n, err := c.RecvMsgs([]socket.Message(ms), flags)
+		if err != nil {
+			err = &net.OpError{Op: "read", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err}
+		}
+		return n, err
+	default:
+		n := 1
+		err := c.RecvMsg(&ms[0], flags)
+		if err != nil {
+			n = 0
+			err = &net.OpError{Op: "read", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err}
+		}
+		if compatFreeBSD32 && ms[0].NN > 0 {
+			adjustFreeBSD32(&ms[0])
+		}
+		return n, err
+	}
+}
+
+// WriteBatch writes a batch of messages.
+//
+// The provided flags is a set of platform-dependent flags, such as
+// syscall.MSG_DONTROUTE.
+//
+// It returns the number of messages written on a successful write.
+//
+// On Linux, a batch write will be optimized.
+// On other platforms, this method will write only a single message.
+func (c *packetHandler) WriteBatch(ms []Message, flags int) (int, error) {
+	if !c.ok() {
+		return 0, errInvalidConn
+	}
+	switch runtime.GOOS {
+	case "linux":
+		n, err := c.SendMsgs([]socket.Message(ms), flags)
+		if err != nil {
+			err = &net.OpError{Op: "write", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err}
+		}
+		return n, err
+	default:
+		n := 1
+		err := c.SendMsg(&ms[0], flags)
+		if err != nil {
+			n = 0
+			err = &net.OpError{Op: "write", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err}
+		}
+		return n, err
+	}
+}