435c0d9fc8
This PR switches the Nomad repository from using govendor to Go modules for managing dependencies. Aspects of the Nomad workflow remain pretty much the same. The usual Makefile targets should continue to work as they always did. The API submodule simply defers to the parent Nomad version on the repository, keeping the semantics of API versioning that currently exists.
118 lines
3.6 KiB
Go
118 lines
3.6 KiB
Go
// Copyright 2012 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"
|
|
|
|
"golang.org/x/net/internal/socket"
|
|
)
|
|
|
|
// BUG(mikio): On Windows, the ReadFrom and WriteTo methods of RawConn
|
|
// are not implemented.
|
|
|
|
// A packetHandler represents the IPv4 datagram handler.
|
|
type packetHandler struct {
|
|
*net.IPConn
|
|
*socket.Conn
|
|
rawOpt
|
|
}
|
|
|
|
func (c *packetHandler) ok() bool { return c != nil && c.IPConn != nil && c.Conn != nil }
|
|
|
|
// ReadFrom reads an IPv4 datagram from the endpoint c, copying the
|
|
// datagram into b. It returns the received datagram as the IPv4
|
|
// header h, the payload p and the control message cm.
|
|
func (c *packetHandler) ReadFrom(b []byte) (h *Header, p []byte, cm *ControlMessage, err error) {
|
|
if !c.ok() {
|
|
return nil, nil, nil, errInvalidConn
|
|
}
|
|
c.rawOpt.RLock()
|
|
m := socket.Message{
|
|
Buffers: [][]byte{b},
|
|
OOB: NewControlMessage(c.rawOpt.cflags),
|
|
}
|
|
c.rawOpt.RUnlock()
|
|
if err := c.RecvMsg(&m, 0); err != nil {
|
|
return nil, nil, nil, &net.OpError{Op: "read", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err}
|
|
}
|
|
var hs []byte
|
|
if hs, p, err = slicePacket(b[:m.N]); err != nil {
|
|
return nil, nil, nil, &net.OpError{Op: "read", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err}
|
|
}
|
|
if h, err = ParseHeader(hs); err != nil {
|
|
return nil, nil, nil, &net.OpError{Op: "read", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err}
|
|
}
|
|
if m.NN > 0 {
|
|
if compatFreeBSD32 {
|
|
adjustFreeBSD32(&m)
|
|
}
|
|
cm = new(ControlMessage)
|
|
if err := cm.Parse(m.OOB[:m.NN]); err != nil {
|
|
return nil, nil, nil, &net.OpError{Op: "read", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err}
|
|
}
|
|
}
|
|
if src, ok := m.Addr.(*net.IPAddr); ok && cm != nil {
|
|
cm.Src = src.IP
|
|
}
|
|
return
|
|
}
|
|
|
|
func slicePacket(b []byte) (h, p []byte, err error) {
|
|
if len(b) < HeaderLen {
|
|
return nil, nil, errHeaderTooShort
|
|
}
|
|
hdrlen := int(b[0]&0x0f) << 2
|
|
return b[:hdrlen], b[hdrlen:], nil
|
|
}
|
|
|
|
// WriteTo writes an IPv4 datagram through the endpoint c, copying the
|
|
// datagram from the IPv4 header h and the payload p. The control
|
|
// message cm allows the datagram path and the outgoing interface to be
|
|
// specified. Currently only Darwin and Linux support this. The cm
|
|
// may be nil if control of the outgoing datagram is not required.
|
|
//
|
|
// The IPv4 header h must contain appropriate fields that include:
|
|
//
|
|
// Version = <must be specified>
|
|
// Len = <must be specified>
|
|
// TOS = <must be specified>
|
|
// TotalLen = <must be specified>
|
|
// ID = platform sets an appropriate value if ID is zero
|
|
// FragOff = <must be specified>
|
|
// TTL = <must be specified>
|
|
// Protocol = <must be specified>
|
|
// Checksum = platform sets an appropriate value if Checksum is zero
|
|
// Src = platform sets an appropriate value if Src is nil
|
|
// Dst = <must be specified>
|
|
// Options = optional
|
|
func (c *packetHandler) WriteTo(h *Header, p []byte, cm *ControlMessage) error {
|
|
if !c.ok() {
|
|
return errInvalidConn
|
|
}
|
|
m := socket.Message{
|
|
OOB: cm.Marshal(),
|
|
}
|
|
wh, err := h.Marshal()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
m.Buffers = [][]byte{wh, p}
|
|
dst := new(net.IPAddr)
|
|
if cm != nil {
|
|
if ip := cm.Dst.To4(); ip != nil {
|
|
dst.IP = ip
|
|
}
|
|
}
|
|
if dst.IP == nil {
|
|
dst.IP = h.Dst
|
|
}
|
|
m.Addr = dst
|
|
if err := c.SendMsg(&m, 0); err != nil {
|
|
return &net.OpError{Op: "write", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Addr: opAddr(dst), Err: err}
|
|
}
|
|
return nil
|
|
}
|