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traefik_allow_countries.go
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traefik_allow_countries.go
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// Package "allow countries" is a Traefik plugin to allow requests based on their country of origin and block everything else.
// Thanks to https://github.com/PascalMinder/GeoBlock for the initial idea.
package traefik_allow_countries
import (
"bufio"
"context"
"fmt"
"log"
"net"
"net/http"
"os"
"strings"
"time"
)
/**********************************
* Define constants *
**********************************/
const (
CountryHeader = "X-IPCountry"
HoursInMillis = 60 * 60 * 1000
PrivateIpAddressesTag = "private"
)
/**********************************
* Define types *
**********************************/
type traefik_allow_countries struct {
next http.Handler
name string
addCountryHeader bool
allowedIPRanges []*IpRangesTimestamp
allowLocalRequests bool
cidrFileFolder string
cidrFileUpdate bool
countries []string
logAllowedRequests bool
logDetails bool
logLocalRequests bool
silentStartUp bool
}
type Config struct {
AddCountryHeader bool `yaml:"addCountryHeader"`
AllowLocalRequests bool `yaml:"allowLocalRequests"`
CidrFileFolder string `yaml:"cidrFileFolder"`
CidrFileUpdate bool `yaml:"cidrFileUpdate"`
Countries []string `yaml:"countries,omitempty"`
LogAllowedRequests bool `yaml:"logAllowedRequests"`
LogDetails bool `yaml:"logDetails"`
LogLocalRequests bool `yaml:"logLocalRequests"`
SilentStartUp bool `yaml:"silentStartUp"`
}
type IpRangesTimestamp struct {
Country string
IpRanges []*net.IPNet
Timestamp time.Time
}
/**********************************
* Define traefik related methods *
**********************************/
// CreateConfig creates the default plugin configuration.
// Returns a empty config object.
func CreateConfig() *Config {
return &Config{
AddCountryHeader: true,
AllowLocalRequests: false,
CidrFileUpdate: true,
LogAllowedRequests: false,
LogDetails: true,
LogLocalRequests: true,
SilentStartUp: true,
}
}
// New creates a new plugin.
// Returns the configured AllowCountries plugin object.
func New(ctx context.Context, next http.Handler, config *Config, name string) (http.Handler, error) {
if len(config.CidrFileFolder) == 0 {
return nil, fmt.Errorf("the CIDR file folder is empty")
}
if len(config.Countries) == 0 {
return nil, fmt.Errorf("the list of allowed countries is empty")
}
if !config.SilentStartUp {
log.Println("Add country header: ", config.AddCountryHeader)
log.Println("Allow local IPs: ", config.AllowLocalRequests)
log.Println("Allowed countries: ", config.Countries)
log.Println("CIDR file folder: ", config.CidrFileFolder)
log.Println("CIDR file update: ", config.CidrFileUpdate)
log.Println("Log allowed requests: ", config.LogAllowedRequests)
log.Println("Log details: ", config.LogDetails)
log.Println("Log local requests: ", config.LogLocalRequests)
}
return &traefik_allow_countries{
next: next,
name: name,
addCountryHeader: config.AddCountryHeader,
allowedIPRanges: InitializeAllowedIPRanges(config.Countries, config.CidrFileFolder),
allowLocalRequests: config.AllowLocalRequests,
cidrFileFolder: config.CidrFileFolder,
cidrFileUpdate: config.CidrFileUpdate,
countries: config.Countries,
logAllowedRequests: config.LogAllowedRequests,
logDetails: config.LogDetails,
logLocalRequests: config.LogLocalRequests,
silentStartUp: config.SilentStartUp,
}, nil
}
// This method is the middleware called during runtime and handling middleware actions.
func (allowCountries *traefik_allow_countries) ServeHTTP(responseWriter http.ResponseWriter, request *http.Request) {
// Collect the IP addresses from the HTTP request.
requestIPAddressList, err := allowCountries.CollectRemoteIP(request)
if err != nil {
// If one of the ip addresses could not be parsed, return status forbidden.
log.Println(err)
responseWriter.WriteHeader(http.StatusForbidden)
return
}
// Find the block of private ip addresses
var privateIPBlocks []*net.IPNet
for index := range allowCountries.allowedIPRanges {
if allowCountries.allowedIPRanges[index].Country == PrivateIpAddressesTag {
privateIPBlocks = allowCountries.allowedIPRanges[index].IpRanges
break
}
}
// Iterate over the addresses.
for _, ipAddress := range requestIPAddressList {
// Check whether the current IP address is a private one.
isPrivateIp := IsPrivateIP(*ipAddress, privateIPBlocks)
if isPrivateIp {
// If local requests are allowed everything is fine.
if allowCountries.allowLocalRequests {
if allowCountries.logLocalRequests {
log.Println("Local IP allowed: ", ipAddress, request.URL)
}
allowCountries.next.ServeHTTP(responseWriter, request)
} else {
// If local requests are prohibited write StatusForbidden.
if allowCountries.logLocalRequests {
log.Println("Local IP denied: ", ipAddress, request.URL)
}
responseWriter.WriteHeader(http.StatusForbidden)
}
// We handled a private IP address here, so we can safely return here.
return
}
// Check country ip ranges.
var found bool = false
for index := range allowCountries.allowedIPRanges {
if allowCountries.allowedIPRanges[index].Country != PrivateIpAddressesTag {
// Check whether an update is needed.
if allowCountries.cidrFileUpdate && time.Since(allowCountries.allowedIPRanges[index].Timestamp).Hours() >= HoursInMillis {
allowCountries.allowedIPRanges[index] = CreateCountryIPBlocks(allowCountries.allowedIPRanges[index].Country, allowCountries.cidrFileFolder)
}
found = IsIpInList(*ipAddress, allowCountries.allowedIPRanges[index].IpRanges)
// If IP was found we can break the current cycle.
if found {
if allowCountries.logAllowedRequests {
log.Printf("%s: Request (%s %s) allowed for IP [%s]", allowCountries.name, request.Host, request.URL, ipAddress)
}
if allowCountries.addCountryHeader {
request.Header.Set(CountryHeader, allowCountries.allowedIPRanges[index].Country)
}
break
}
}
}
if !found {
log.Printf("%s: Request (%s %s) denied for IP [%s]", allowCountries.name, request.Host, request.URL, ipAddress)
responseWriter.WriteHeader(http.StatusForbidden)
return
}
}
allowCountries.next.ServeHTTP(responseWriter, request)
}
/**********************************
* Private methods *
**********************************/
// This method collects the remote IP address.
// It tries to parse the IP from the HTTP request.
// Returns the parsed IP and no error on success, otherwise the so far generated list and an error.
func (allowCountries *traefik_allow_countries) CollectRemoteIP(request *http.Request) ([]*net.IP, error) {
var ipList []*net.IP
// Helper method to split a string at char ','
splitFn := func(c rune) bool {
return c == ','
}
// Try to parse from header "X-Forwarded-For"
xForwardedForValue := request.Header.Get("X-Forwarded-For")
xForwardedForIPs := strings.FieldsFunc(xForwardedForValue, splitFn)
for _, value := range xForwardedForIPs {
ipAddress, err := ParseIP(value)
if err != nil {
return ipList, fmt.Errorf("parsing failed: %s", err)
}
ipList = append(ipList, &ipAddress)
}
// Try to parse from header "X-Real-IP"
xRealIpValue := request.Header.Get("X-Real-IP")
xRealIpIPs := strings.FieldsFunc(xRealIpValue, splitFn)
for _, value := range xRealIpIPs {
ipAddress, err := ParseIP(value)
if err != nil {
return ipList, fmt.Errorf("parsing failed: %s", err)
}
ipList = append(ipList, &ipAddress)
}
return ipList, nil
}
// Creates a new IP ranges timestamp entity for the provided country.
func CreateCountryIPBlocks(country string, cidrFileFolder string) *IpRangesTimestamp {
var countryIPBlocks []*net.IPNet
for _, ipType := range []string{
"ipv4",
"ipv6",
} {
lines, err := ReadFile(cidrFileFolder + "/" + ipType + "/" + strings.ToLower(country) + ".cidr")
if err != nil {
panic(fmt.Errorf("failed to read file for version %q and country %q: %v", ipType, country, err))
}
for _, value := range lines {
_, block, err := net.ParseCIDR(value)
if err != nil {
panic(fmt.Errorf("parse error on %q: %v", value, err))
}
countryIPBlocks = append(countryIPBlocks, block)
}
}
return &IpRangesTimestamp{
Country: country,
IpRanges: countryIPBlocks,
Timestamp: time.Now(),
}
}
// This method initializes the allowed IP ranges.
// It uses a predefined range of private CIDR addresses and reads cidr files based on the provided countries.
// Returns a list of IP ranges timestamp objects.
func InitializeAllowedIPRanges(countries []string, cidrFileFolder string) []*IpRangesTimestamp {
var allowedIPBlocks []*IpRangesTimestamp
// Append the private IP addresses first.
allowedIPBlocks = append(allowedIPBlocks, &IpRangesTimestamp{
Country: PrivateIpAddressesTag,
IpRanges: InitializePrivateIPBlocks(),
Timestamp: time.Now(),
})
// Now read the country files and append them.
for _, country := range countries {
allowedIPBlocks = append(allowedIPBlocks, CreateCountryIPBlocks(country, cidrFileFolder))
}
return allowedIPBlocks
}
// This method initializes a list of private IP addresses.
// It uses a predefined range of CIDR addresses.
// Returns a list of private IP blocks.
// https://stackoverflow.com/questions/41240761/check-if-ip-address-is-in-private-network-space
func InitializePrivateIPBlocks() []*net.IPNet {
var privateIPBlocks []*net.IPNet
for _, cidr := range []string{
"127.0.0.0/8", // IPv4 loopback
"10.0.0.0/8", // RFC1918
"172.16.0.0/12", // RFC1918
"192.168.0.0/16", // RFC1918
"169.254.0.0/16", // RFC3927 link-local
"::1/128", // IPv6 loopback
"fe80::/10", // IPv6 link-local
"fc00::/7", // IPv6 unique local addr
} {
_, block, err := net.ParseCIDR(cidr)
if err != nil {
panic(fmt.Errorf("parse error on %q: %v", cidr, err))
}
privateIPBlocks = append(privateIPBlocks, block)
}
return privateIPBlocks
}
// This method checks whether a provided IP is a private IP.
// If this is the case it returns true, otherwise false.
// https://stackoverflow.com/questions/41240761/check-if-ip-address-is-in-private-network-space
func IsPrivateIP(ip net.IP, privateIPBlocks []*net.IPNet) bool {
if ip.IsLoopback() || ip.IsLinkLocalUnicast() || ip.IsLinkLocalMulticast() {
return true
}
return IsIpInList(ip, privateIPBlocks)
}
// Checks whether a string is in a list of strings.
// Returns true if this is the case, otherwise returns false.
func IsIpInList(ip net.IP, list []*net.IPNet) bool {
for _, block := range list {
if block.Contains(ip) {
return true
}
}
return false
}
// Tries to parse the IP from a provided address.
// Returns the ip and no error on success, otherwise returns nil and the occured error.
func ParseIP(address string) (net.IP, error) {
ipAddress := net.ParseIP(address)
if ipAddress == nil {
return nil, fmt.Errorf("unable to parse IP from address [%s]", address)
}
return ipAddress, nil
}
// Reads a file based on the provided file path.
// Returns each line in a list on success, otherwise nil and an error.
func ReadFile(file string) ([]string, error) {
var lines []string
// Open file
f, err := os.Open(file)
if err != nil {
return lines, err
}
// Remember to close the file at the end of the program.
defer f.Close()
// Read the file line by line using scanner.
scanner := bufio.NewScanner(f)
for scanner.Scan() {
lines = append(lines, scanner.Text())
}
if err := scanner.Err(); err != nil {
return lines, err
} else {
return lines, nil
}
}