49 lines
1.3 KiB
Go
49 lines
1.3 KiB
Go
package http3
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import (
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"net"
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"strings"
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)
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// An addrList represents a list of network endpoint addresses.
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// Copy from [net.addrList] and change type from [net.Addr] to [net.IPAddr]
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type addrList []net.IPAddr
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// isIPv4 reports whether addr contains an IPv4 address.
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func isIPv4(addr net.IPAddr) bool {
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return addr.IP.To4() != nil
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}
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// isNotIPv4 reports whether addr does not contain an IPv4 address.
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func isNotIPv4(addr net.IPAddr) bool { return !isIPv4(addr) }
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// forResolve returns the most appropriate address in address for
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// a call to ResolveTCPAddr, ResolveUDPAddr, or ResolveIPAddr.
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// IPv4 is preferred, unless addr contains an IPv6 literal.
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func (addrs addrList) forResolve(network, addr string) net.IPAddr {
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var want6 bool
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switch network {
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case "ip":
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// IPv6 literal (addr does NOT contain a port)
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want6 = strings.ContainsRune(addr, ':')
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case "tcp", "udp":
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// IPv6 literal. (addr contains a port, so look for '[')
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want6 = strings.ContainsRune(addr, '[')
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}
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if want6 {
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return addrs.first(isNotIPv4)
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}
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return addrs.first(isIPv4)
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}
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// first returns the first address which satisfies strategy, or if
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// none do, then the first address of any kind.
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func (addrs addrList) first(strategy func(net.IPAddr) bool) net.IPAddr {
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for _, addr := range addrs {
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if strategy(addr) {
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return addr
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}
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}
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return addrs[0]
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}
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