go.net/ipv4: new package
Package ipv4 implements IP-level socket options for the Internet
Protocol version 4. It also provides raw IP socket access methods
including IPv4 header manipulation.
Fixes golang/go#3684.
Fixes golang/go#3820.
This CL requires CL 6426047;
net: add read, write message methods to IPConn, UDPConn
R=rsc, dave, alex.brainman
CC=gobot, golang-dev
https://golang.org/cl/6482044
diff --git a/ipv4/dgramopt_posix.go b/ipv4/dgramopt_posix.go
new file mode 100644
index 0000000..0ba81c2
--- /dev/null
+++ b/ipv4/dgramopt_posix.go
@@ -0,0 +1,125 @@
+// 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.
+
+// +build darwin freebsd linux netbsd openbsd windows
+
+package ipv4
+
+import (
+ "net"
+ "syscall"
+)
+
+// MulticastTTL returns the time-to-live field value for outgoing
+// multicast packets.
+func (c *dgramOpt) MulticastTTL() (int, error) {
+ if !c.ok() {
+ return 0, syscall.EINVAL
+ }
+ fd, err := c.sysfd()
+ if err != nil {
+ return 0, err
+ }
+ return ipv4MulticastTTL(fd)
+}
+
+// SetMulticastTTL sets the time-to-live field value for future
+// outgoing multicast packets.
+func (c *dgramOpt) SetMulticastTTL(ttl int) error {
+ if !c.ok() {
+ return syscall.EINVAL
+ }
+ fd, err := c.sysfd()
+ if err != nil {
+ return err
+ }
+ return setIPv4MulticastTTL(fd, ttl)
+}
+
+// MulticastInterface returns the default interface for multicast
+// packet transmissions.
+func (c *dgramOpt) MulticastInterface() (*net.Interface, error) {
+ if !c.ok() {
+ return nil, syscall.EINVAL
+ }
+ fd, err := c.sysfd()
+ if err != nil {
+ return nil, err
+ }
+ return ipv4MulticastInterface(fd)
+}
+
+// SetMulticastInterface sets the default interface for future
+// multicast packet transmissions.
+func (c *dgramOpt) SetMulticastInterface(ifi *net.Interface) error {
+ if !c.ok() {
+ return syscall.EINVAL
+ }
+ fd, err := c.sysfd()
+ if err != nil {
+ return err
+ }
+ return setIPv4MulticastInterface(fd, ifi)
+}
+
+// MulticastLoopback reports whether transmitted multicast packets
+// should be copied and send back to the originator.
+func (c *dgramOpt) MulticastLoopback() (bool, error) {
+ if !c.ok() {
+ return false, syscall.EINVAL
+ }
+ fd, err := c.sysfd()
+ if err != nil {
+ return false, err
+ }
+ return ipv4MulticastLoopback(fd)
+}
+
+// SetMulticastLoopback sets whether transmitted multicast packets
+// should be copied and send back to the originator.
+func (c *dgramOpt) SetMulticastLoopback(on bool) error {
+ if !c.ok() {
+ return syscall.EINVAL
+ }
+ fd, err := c.sysfd()
+ if err != nil {
+ return err
+ }
+ return setIPv4MulticastLoopback(fd, on)
+}
+
+// JoinGroup joins the group address group on the interface ifi.
+// It uses the system assigned multicast interface when ifi is nil,
+// although this is not recommended because the assignment depends on
+// platforms and sometimes it might require routing configuration.
+func (c *dgramOpt) JoinGroup(ifi *net.Interface, group net.Addr) error {
+ if !c.ok() {
+ return syscall.EINVAL
+ }
+ fd, err := c.sysfd()
+ if err != nil {
+ return err
+ }
+ grp := netAddrToIP4(group)
+ if grp == nil {
+ return errMissingAddress
+ }
+ return joinIPv4Group(fd, ifi, grp)
+}
+
+// LeaveGroup leaves the group address group on the interface ifi.
+func (c *dgramOpt) LeaveGroup(ifi *net.Interface, group net.Addr) error {
+ if !c.ok() {
+ return syscall.EINVAL
+ }
+ fd, err := c.sysfd()
+ if err != nil {
+ return err
+ }
+ grp := netAddrToIP4(group)
+ if grp == nil {
+ return errMissingAddress
+ }
+ return leaveIPv4Group(fd, ifi, grp)
+}
