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net: document that ListenMulticastUDP is for simple applications

Also mentions golang.org/x/net/ipv4 and golang.org/x/net/ipv6.

Change-Id: I653deac7a5e2b129237655a72d6c91207f1b1685
Reviewed-on: https://go-review.googlesource.com/9779
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This commit is contained in:
Mikio Hara 2015-05-07 19:10:29 +09:00
parent ceb8fe45da
commit 49894be7b1
2 changed files with 30 additions and 16 deletions

View File

@ -200,9 +200,16 @@ func ListenUDP(net string, laddr *UDPAddr) (*UDPConn, error) {
}
// ListenMulticastUDP listens for incoming multicast UDP packets
// addressed to the group address gaddr on ifi, which specifies the
// interface to join. ListenMulticastUDP uses default multicast
// interface if ifi is nil.
func ListenMulticastUDP(net string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) {
return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: gaddr, Err: syscall.EPLAN9}
// addressed to the group address gaddr on the interface ifi.
// Network must be "udp", "udp4" or "udp6".
// ListenMulticastUDP 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.
//
// ListenMulticastUDP is just for convenience of simple, small
// applications. There are golang.org/x/net/ipv4 and
// golang.org/x/net/ipv6 packages for general purpose uses.
func ListenMulticastUDP(network string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) {
return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr, Err: syscall.EPLAN9}
}

View File

@ -220,32 +220,39 @@ func ListenUDP(net string, laddr *UDPAddr) (*UDPConn, error) {
}
// ListenMulticastUDP listens for incoming multicast UDP packets
// addressed to the group address gaddr on ifi, which specifies the
// interface to join. ListenMulticastUDP uses default multicast
// interface if ifi is nil.
func ListenMulticastUDP(net string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) {
switch net {
// addressed to the group address gaddr on the interface ifi.
// Network must be "udp", "udp4" or "udp6".
// ListenMulticastUDP 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.
//
// ListenMulticastUDP is just for convenience of simple, small
// applications. There are golang.org/x/net/ipv4 and
// golang.org/x/net/ipv6 packages for general purpose uses.
func ListenMulticastUDP(network string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) {
switch network {
case "udp", "udp4", "udp6":
default:
return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: gaddr, Err: UnknownNetworkError(net)}
return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr, Err: UnknownNetworkError(network)}
}
if gaddr == nil || gaddr.IP == nil {
return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: gaddr, Err: errMissingAddress}
return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr, Err: errMissingAddress}
}
fd, err := internetSocket(net, gaddr, nil, noDeadline, syscall.SOCK_DGRAM, 0, "listen")
fd, err := internetSocket(network, gaddr, nil, noDeadline, syscall.SOCK_DGRAM, 0, "listen")
if err != nil {
return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: gaddr, Err: err}
return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr, Err: err}
}
c := newUDPConn(fd)
if ip4 := gaddr.IP.To4(); ip4 != nil {
if err := listenIPv4MulticastUDP(c, ifi, ip4); err != nil {
c.Close()
return nil, &OpError{Op: "listen", Net: net, Source: c.fd.laddr, Addr: &IPAddr{IP: ip4}, Err: err}
return nil, &OpError{Op: "listen", Net: network, Source: c.fd.laddr, Addr: &IPAddr{IP: ip4}, Err: err}
}
} else {
if err := listenIPv6MulticastUDP(c, ifi, gaddr.IP); err != nil {
c.Close()
return nil, &OpError{Op: "listen", Net: net, Source: c.fd.laddr, Addr: &IPAddr{IP: gaddr.IP}, Err: err}
return nil, &OpError{Op: "listen", Net: network, Source: c.fd.laddr, Addr: &IPAddr{IP: gaddr.IP}, Err: err}
}
}
return c, nil