54 lines
1.1 KiB
Go
54 lines
1.1 KiB
Go
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package ssdp
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import "net"
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// Interfaces specify target interfaces to multicast. If no interfaces are
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// specified, all interfaces will be used.
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var Interfaces []net.Interface
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func interfaces() []net.Interface {
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if Interfaces == nil {
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Interfaces = interfacesIPv4()
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}
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return Interfaces
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}
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func interfacesIPv4() []net.Interface {
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iflist, err := net.Interfaces()
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if err != nil {
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logf("failed to list interfaces: %s", err)
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return make([]net.Interface, 0)
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}
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list := make([]net.Interface, 0, len(iflist))
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for _, ifi := range iflist {
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if !hasLinkUp(&ifi) || !hasIPv4Address(&ifi) {
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continue
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}
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list = append(list, ifi)
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}
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return list
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}
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// hasLinkUp checks an I/F have link-up or not.
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func hasLinkUp(ifi *net.Interface) bool {
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return ifi.Flags&net.FlagUp != 0
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}
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// hasIPv4Address checks an I/F have IPv4 address.
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func hasIPv4Address(ifi *net.Interface) bool {
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addrs, err := ifi.Addrs()
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if err != nil {
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return false
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}
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for _, a := range addrs {
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ip, _, err := net.ParseCIDR(a.String())
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if err != nil {
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continue
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}
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if len(ip.To4()) == net.IPv4len && !ip.IsUnspecified() {
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return true
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}
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}
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return false
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}
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