83 lines
2.0 KiB
Go
83 lines
2.0 KiB
Go
package origin
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import (
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"fmt"
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"net"
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)
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const (
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// Used to discover HA Warp servers
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srvService = "warp"
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srvProto = "tcp"
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srvName = "cloudflarewarp.com"
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)
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func ResolveEdgeIPs(addresses []string) ([]*net.TCPAddr, error) {
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if len(addresses) > 0 {
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var tcpAddrs []*net.TCPAddr
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for _, address := range addresses {
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// Addresses specified (for testing, usually)
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tcpAddr, err := net.ResolveTCPAddr("tcp", address)
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if err != nil {
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return nil, err
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}
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tcpAddrs = append(tcpAddrs, tcpAddr)
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}
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return tcpAddrs, nil
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}
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// HA service discovery lookup
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_, addrs, err := net.LookupSRV(srvService, srvProto, srvName)
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if err != nil {
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return nil, err
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}
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var resolvedIPsPerCNAME [][]*net.TCPAddr
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var lookupErr error
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for _, addr := range addrs {
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ips, err := ResolveSRVToTCP(addr)
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if err != nil || len(ips) == 0 {
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// don't return early, we might be able to resolve other addresses
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lookupErr = err
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continue
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}
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resolvedIPsPerCNAME = append(resolvedIPsPerCNAME, ips)
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}
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ips := FlattenServiceIPs(resolvedIPsPerCNAME)
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if lookupErr == nil && len(ips) == 0 {
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return nil, fmt.Errorf("Unknown service discovery error")
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}
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return ips, lookupErr
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}
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func ResolveSRVToTCP(srv *net.SRV) ([]*net.TCPAddr, error) {
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ips, err := net.LookupIP(srv.Target)
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if err != nil {
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return nil, err
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}
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addrs := make([]*net.TCPAddr, len(ips))
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for i, ip := range ips {
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addrs[i] = &net.TCPAddr{IP: ip, Port: int(srv.Port)}
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}
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return addrs, nil
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}
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// FlattenServiceIPs transposes and flattens the input slices such that the
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// first element of the n inner slices are the first n elements of the result.
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func FlattenServiceIPs(ipsByService [][]*net.TCPAddr) []*net.TCPAddr {
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var result []*net.TCPAddr
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for len(ipsByService) > 0 {
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filtered := ipsByService[:0]
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for _, ips := range ipsByService {
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if len(ips) == 0 {
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// sanity check
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continue
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}
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result = append(result, ips[0])
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if len(ips) > 1 {
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filtered = append(filtered, ips[1:])
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}
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}
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ipsByService = filtered
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}
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return result
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}
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