/
net.go
69 lines (57 loc) · 1.36 KB
/
net.go
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package mdns
import (
"log"
"net"
"golang.org/x/net/ipv4"
"golang.org/x/net/ipv6"
)
type multicastConn struct {
conn *net.UDPConn
addr net.Addr
}
func newConn(addr *net.UDPAddr) (*multicastConn, error) {
ifaces, err := net.Interfaces()
if err != nil {
return nil, err
}
c, err := net.ListenUDP("udp", addr)
if err != nil {
return nil, err
}
if addr.IP.To4() != nil {
pc := ipv4.NewPacketConn(c)
pc.SetMulticastTTL(255)
for _, iface := range ifaces {
if (iface.Flags&net.FlagUp == 0) || (iface.Flags&net.FlagMulticast == 0) {
continue
}
err := pc.JoinGroup(&iface, addr)
if err != nil {
log.Println("Unable to join IPv4 mDNS multicast group", iface, err)
}
}
} else {
pc := ipv6.NewPacketConn(c)
for _, iface := range ifaces {
if (iface.Flags&net.FlagUp == 0) || (iface.Flags&net.FlagMulticast == 0) {
continue
}
err := pc.JoinGroup(&iface, addr)
if err != nil {
log.Println("Unable to join IPv6 mDNS multicast group", iface, err)
}
}
}
return &multicastConn{conn: c, addr: addr}, nil
}
func (c *multicastConn) send(b []byte, addr net.Addr) error {
_, err := c.conn.WriteTo(b, addr)
return err
}
func (c *multicastConn) sendMulticast(b []byte) error {
_, err := c.conn.WriteTo(b, c.addr)
return err
}
func (c *multicastConn) recv(b []byte) (int, net.Addr, error) {
return c.conn.ReadFrom(b)
}