package goupnp import ( "io" "net" "github.com/huin/goupnp/httpu" ) // httpuClient creates a HTTPU client that multiplexes to all multicast-capable // IPv4 addresses on the host. Returns a function to clean up once the client is // no longer required. func httpuClient() (httpu.ClientInterface, func(), error) { addrs, err := localIPv4MCastAddrs() if err != nil { return nil, nil, ctxError(err, "requesting host IPv4 addresses") } closers := make([]io.Closer, 0, len(addrs)) delegates := make([]httpu.ClientInterface, 0, len(addrs)) for _, addr := range addrs { c, err := httpu.NewHTTPUClientAddr(addr) if err != nil { return nil, nil, ctxErrorf(err, "creating HTTPU client for address %s", addr) } closers = append(closers, c) delegates = append(delegates, c) } closer := func() { for _, c := range closers { c.Close() } } return httpu.NewMultiClient(delegates), closer, nil } // localIPv2MCastAddrs returns the set of IPv4 addresses on multicast-able // network interfaces. func localIPv4MCastAddrs() ([]string, error) { ifaces, err := net.Interfaces() if err != nil { return nil, ctxError(err, "requesting host interfaces") } // Find the set of addresses to listen on. var addrs []string for _, iface := range ifaces { if iface.Flags&net.FlagMulticast == 0 || iface.Flags&net.FlagLoopback != 0 || iface.Flags&net.FlagUp == 0 { // Does not support multicast or is a loopback address. continue } ifaceAddrs, err := iface.Addrs() if err != nil { return nil, ctxErrorf(err, "finding addresses on interface %s", iface.Name) } for _, netAddr := range ifaceAddrs { addr, ok := netAddr.(*net.IPNet) if !ok { // Not an IPNet address. continue } if addr.IP.To4() == nil { // Not IPv4. continue } addrs = append(addrs, addr.IP.String()) } } return addrs, nil }