75 lines
1.6 KiB
Go
75 lines
1.6 KiB
Go
package ip
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import (
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"net"
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"net/http"
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"strings"
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)
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const (
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xForwardedFor = "X-Forwarded-For"
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)
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// Strategy a strategy for IP selection.
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type Strategy interface {
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GetIP(req *http.Request) string
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}
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// RemoteAddrStrategy a strategy that always return the remote address.
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type RemoteAddrStrategy struct{}
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// GetIP returns the selected IP.
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func (s *RemoteAddrStrategy) GetIP(req *http.Request) string {
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ip, _, err := net.SplitHostPort(req.RemoteAddr)
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if err != nil {
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return req.RemoteAddr
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}
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return ip
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}
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// DepthStrategy a strategy based on the depth inside the X-Forwarded-For from right to left.
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type DepthStrategy struct {
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Depth int
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}
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// GetIP return the selected IP.
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func (s *DepthStrategy) GetIP(req *http.Request) string {
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xff := req.Header.Get(xForwardedFor)
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xffs := strings.Split(xff, ",")
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if len(xffs) < s.Depth {
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return ""
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}
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return strings.TrimSpace(xffs[len(xffs)-s.Depth])
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}
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// PoolStrategy is a strategy based on an IP Checker.
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// It allows to check whether addresses are in a given pool of IPs.
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type PoolStrategy struct {
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Checker *Checker
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}
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// GetIP checks the list of Forwarded IPs (most recent first) against the
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// Checker pool of IPs. It returns the first IP that is not in the pool, or the
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// empty string otherwise.
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func (s *PoolStrategy) GetIP(req *http.Request) string {
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if s.Checker == nil {
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return ""
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}
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xff := req.Header.Get(xForwardedFor)
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xffs := strings.Split(xff, ",")
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for i := len(xffs) - 1; i >= 0; i-- {
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xffTrimmed := strings.TrimSpace(xffs[i])
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if len(xffTrimmed) == 0 {
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continue
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}
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if contain, _ := s.Checker.Contains(xffTrimmed); !contain {
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return xffTrimmed
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}
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}
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return ""
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}
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