78 lines
1.7 KiB
Go
78 lines
1.7 KiB
Go
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// Copyright 2020 Lauris BH. All rights reserved.
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// Use of this source code is governed by a MIT-style
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// license that can be found in the LICENSE file.
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package proxy
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// Ported from Goji's middleware, source:
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// https://github.com/zenazn/goji/tree/master/web/middleware
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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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var xForwardedFor = http.CanonicalHeaderKey("X-Forwarded-For")
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var xRealIP = http.CanonicalHeaderKey("X-Real-IP")
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// ForwardedHeaders is a middleware that sets a http.Request's RemoteAddr to the results
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// of parsing either the X-Real-IP header or the X-Forwarded-For header (in that
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// order).
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func ForwardedHeaders(options ...*ForwardedHeadersOptions) func(h http.Handler) http.Handler {
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opt := defaultOptions
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if len(options) > 0 {
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opt = options[0]
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}
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return func(h http.Handler) http.Handler {
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fn := func(w http.ResponseWriter, r *http.Request) {
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// Treat unix socket as 127.0.0.1
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if r.RemoteAddr == "@" {
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r.RemoteAddr = "127.0.0.1:0"
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}
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if rip := realIP(r, opt); len(rip) > 0 {
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r.RemoteAddr = net.JoinHostPort(rip, "0")
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}
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h.ServeHTTP(w, r)
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}
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return http.HandlerFunc(fn)
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}
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}
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func realIP(r *http.Request, options *ForwardedHeadersOptions) string {
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host, _, err := net.SplitHostPort(r.RemoteAddr)
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if err != nil {
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return ""
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}
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if !options.isTrustedProxy(net.ParseIP(host)) {
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return ""
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}
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var ip string
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if xrip := r.Header.Get(xRealIP); xrip != "" {
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ip = xrip
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} else if xff := r.Header.Get(xForwardedFor); xff != "" {
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p := 0
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for i := options.ForwardLimit; i > 0; i-- {
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if p > 0 {
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xff = xff[:p-2]
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}
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p = strings.LastIndex(xff, ", ")
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if p < 0 {
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p = 0
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break
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} else {
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p += 2
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}
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}
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ip = xff[p:]
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}
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return ip
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}
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