119 lines
3.0 KiB
Go
119 lines
3.0 KiB
Go
/*
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* Copyright 2024 Jonas Kaninda
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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package middlewares
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import (
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"github.com/jkaninda/goma-gateway/pkg/logger"
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"net"
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"net/http"
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"strings"
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)
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type AccessPolicy struct {
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Action string
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SourceRanges []string
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}
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func (access AccessPolicy) AccessPolicyMiddleware(next http.Handler) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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// Get the client's IP address
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clientIP, _, err := net.SplitHostPort(getRealIP(r))
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if err != nil {
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logger.Error("Unable to parse IP address")
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RespondWithError(w, http.StatusUnauthorized, "Unable to parse IP address")
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return
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}
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// Check IP against source ranges
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isAllowed := access.Action != "DENY"
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for _, entry := range access.SourceRanges {
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if isIPAllowed(clientIP, entry) {
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if isAllowed {
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next.ServeHTTP(w, r)
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} else {
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logger.Error("%s: IP address in the blocklist, access not allowed", clientIP)
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RespondWithError(w, http.StatusForbidden, http.StatusText(http.StatusForbidden))
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}
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return
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}
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}
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// Final response for disallowed IPs
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if isAllowed {
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logger.Error("%s: IP address not allowed", clientIP)
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RespondWithError(w, http.StatusForbidden, http.StatusText(http.StatusForbidden))
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} else {
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next.ServeHTTP(w, r)
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}
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})
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}
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// isIPAllowed checks if a client IP matches an entry (range or single IP).
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func isIPAllowed(clientIP, entry string) bool {
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if strings.Contains(entry, "-") {
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// Handle IP range
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startIP, endIP, err := parseIPRange(entry)
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return err == nil && ipInRange(clientIP, startIP, endIP)
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}
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// Handle single IP
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return clientIP == entry
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}
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// / Parse a range string into start and end IPs
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func parseIPRange(rangeStr string) (string, string, error) {
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parts := strings.Split(rangeStr, "-")
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if len(parts) != 2 {
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return "", "", http.ErrAbortHandler
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}
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startIP := strings.TrimSpace(parts[0])
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endIP := strings.TrimSpace(parts[1])
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if net.ParseIP(startIP) == nil || net.ParseIP(endIP) == nil {
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return "", "", http.ErrAbortHandler
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}
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return startIP, endIP, nil
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}
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// Check if an IP is in range
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func ipInRange(ipStr, startIP, endIP string) bool {
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ip := net.ParseIP(ipStr)
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start := net.ParseIP(startIP)
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end := net.ParseIP(endIP)
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if ip == nil || start == nil || end == nil {
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return false
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}
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ipBytes := ip.To4()
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startBytes := start.To4()
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endBytes := end.To4()
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if ipBytes == nil || startBytes == nil || endBytes == nil {
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return false
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}
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for i := 0; i < 4; i++ {
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if ipBytes[i] < startBytes[i] || ipBytes[i] > endBytes[i] {
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return false
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}
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}
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return true
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}
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