Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Add function to get real IP from request headers #17

Merged
merged 1 commit into from
Apr 9, 2024
Merged

Add function to get real IP from request headers #17

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
80 changes: 80 additions & 0 deletions realip.go
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,80 @@
package rest

import (
"bytes"
"fmt"
"net"
"net/http"
"strings"
)

type ipRange struct {
start net.IP
end net.IP
}

var privateRanges = []ipRange{
{start: net.ParseIP("10.0.0.0"), end: net.ParseIP("10.255.255.255")},
{start: net.ParseIP("100.64.0.0"), end: net.ParseIP("100.127.255.255")},
{start: net.ParseIP("172.16.0.0"), end: net.ParseIP("172.31.255.255")},
{start: net.ParseIP("192.0.0.0"), end: net.ParseIP("192.0.0.255")},
{start: net.ParseIP("192.168.0.0"), end: net.ParseIP("192.168.255.255")},
{start: net.ParseIP("198.18.0.0"), end: net.ParseIP("198.19.255.255")},
{start: net.ParseIP("::1"), end: net.ParseIP("::1")},
{start: net.ParseIP("fc00::"), end: net.ParseIP("fdff:ffff:ffff:ffff:ffff:ffff:ffff:ffff")},
{start: net.ParseIP("fe80::"), end: net.ParseIP("febf:ffff:ffff:ffff:ffff:ffff:ffff:ffff")},
}

// Get returns real ip from the given request
// Prioritize public IPs over private IPs
func GetRealIP(r *http.Request) (string, error) {
var firstIP string
for _, h := range []string{"X-Forwarded-For", "X-Real-Ip"} {
addresses := strings.Split(r.Header.Get(h), ",")
for i := len(addresses) - 1; i >= 0; i-- {
ip := strings.TrimSpace(addresses[i])
realIP := net.ParseIP(ip)
if firstIP == "" && realIP != nil {
firstIP = ip
}
if !realIP.IsGlobalUnicast() || isPrivateSubnet(realIP) {
continue
}
return ip, nil
}
}

if firstIP != "" {
return firstIP, nil
}

ip, _, err := net.SplitHostPort(r.RemoteAddr)
if err != nil {
return "", fmt.Errorf("can't parse ip %q: %w", r.RemoteAddr, err)
}
if netIP := net.ParseIP(ip); netIP == nil {
return "", fmt.Errorf("no valid ip found")
}

return ip, nil
}

// isPrivateSubnet - check to see if this ip is in a private subnet
func isPrivateSubnet(ipAddress net.IP) bool {

// inRange - check to see if a given ip address is within a range given
inRange := func(r ipRange, ipAddress net.IP) bool {
// ensure the IPs are in the same format for comparison
ipAddress = ipAddress.To16()
r.start = r.start.To16()
r.end = r.end.To16()
return bytes.Compare(ipAddress, r.start) >= 0 && bytes.Compare(ipAddress, r.end) <= 0
}

for _, r := range privateRanges {
if inRange(r, ipAddress) {
return true
}
}
return false
}
145 changes: 145 additions & 0 deletions realip_test.go
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,145 @@
package rest

import (
"log"
"net/http"
"net/http/httptest"
"testing"
"time"

"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
)

func TestGetFromHeaders(t *testing.T) {
t.Run("single X-Real-IP", func(t *testing.T) {
req, err := http.NewRequest("GET", "/something", http.NoBody)
assert.NoError(t, err)
req.Header.Add("Something", "1234567")
req.Header.Add("X-Real-IP", "8.8.8.8")
adr, err := GetRealIP(req)
require.NoError(t, err)
assert.Equal(t, "8.8.8.8", adr)
})
t.Run("X-Forwarded-For last public", func(t *testing.T) {
req, err := http.NewRequest("GET", "/something", http.NoBody)
assert.NoError(t, err)
req.Header.Add("Something", "1234567")
req.Header.Add("X-Forwarded-For", "8.8.8.8,1.1.1.2, 30.30.30.1")
adr, err := GetRealIP(req)
require.NoError(t, err)
assert.Equal(t, "30.30.30.1", adr)
})
t.Run("X-Forwarded-For last private", func(t *testing.T) {
req, err := http.NewRequest("GET", "/something", http.NoBody)
assert.NoError(t, err)
req.Header.Add("Something", "1234567")
req.Header.Add("X-Forwarded-For", "8.8.8.8,1.1.1.2,192.168.1.1,10.0.0.65")
adr, err := GetRealIP(req)
require.NoError(t, err)
assert.Equal(t, "1.1.1.2", adr)
})
t.Run("X-Forwarded-For public im the middle", func(t *testing.T) {
req, err := http.NewRequest("GET", "/something", http.NoBody)
assert.NoError(t, err)
req.Header.Add("Something", "1234567")
req.Header.Add("X-Forwarded-For", "192.168.1.1, 8.8.8.8, 10.0.0.65")
adr, err := GetRealIP(req)
require.NoError(t, err)
assert.Equal(t, "8.8.8.8", adr)
})
t.Run("X-Forwarded-For all private", func(t *testing.T) {
req, err := http.NewRequest("GET", "/something", http.NoBody)
assert.NoError(t, err)
req.Header.Add("Something", "1234567")
req.Header.Add("X-Forwarded-For", "192.168.1.1,10.0.0.65")
adr, err := GetRealIP(req)
require.NoError(t, err)
assert.Equal(t, "10.0.0.65", adr)
})
t.Run("X-Forwarded-For public, X-Real-IP private", func(t *testing.T) {
req, err := http.NewRequest("GET", "/something", http.NoBody)
assert.NoError(t, err)
req.Header.Add("Something", "1234567")
req.Header.Add("X-Forwarded-For", "30.30.30.1")
req.Header.Add("X-Real-Ip", "10.0.0.1")
adr, err := GetRealIP(req)
require.NoError(t, err)
assert.Equal(t, "30.30.30.1", adr)
})
t.Run("X-Forwarded-For and X-Real-IP public", func(t *testing.T) {
req, err := http.NewRequest("GET", "/something", http.NoBody)
assert.NoError(t, err)
req.Header.Add("Something", "1234567")
req.Header.Add("X-Forwarded-For", "30.30.30.1")
req.Header.Add("X-Real-Ip", "8.8.8.8")
adr, err := GetRealIP(req)
require.NoError(t, err)
assert.Equal(t, "30.30.30.1", adr)
})
t.Run("X-Forwarded-For private and X-Real-IP public", func(t *testing.T) {
req, err := http.NewRequest("GET", "/something", http.NoBody)
assert.NoError(t, err)
req.Header.Add("Something", "1234567")
req.Header.Add("X-Forwarded-For", "10.0.0.2,192.168.1.1")
req.Header.Add("X-Real-Ip", "8.8.8.8")
adr, err := GetRealIP(req)
require.NoError(t, err)
assert.Equal(t, "8.8.8.8", adr)
})
t.Run("RemoteAddr fallback", func(t *testing.T) {
req, err := http.NewRequest("GET", "/something", http.NoBody)
assert.NoError(t, err)
req.RemoteAddr = "192.0.2.1:1234"
adr, err := GetRealIP(req)
require.NoError(t, err)
assert.Equal(t, "192.0.2.1", adr)
})
t.Run("X-Forwarded-For and X-Real-IP missing, no RemoteAddr either", func(t *testing.T) {
req, err := http.NewRequest("GET", "/something", http.NoBody)
assert.NoError(t, err)
ip, err := GetRealIP(req)
assert.Error(t, err)
assert.Equal(t, "", ip)
})
t.Run("X-Real-IP IPv6", func(t *testing.T) {
req, err := http.NewRequest("GET", "/something", http.NoBody)
assert.NoError(t, err)
req.Header.Add("X-Real-IP", "2001:0db8:85a3:0000:0000:8a2e:0370:7334")
adr, err := GetRealIP(req)
require.NoError(t, err)
assert.Equal(t, "2001:0db8:85a3:0000:0000:8a2e:0370:7334", adr)
})
t.Run("X-Forwarded-For last IPv6 public", func(t *testing.T) {
req, err := http.NewRequest("GET", "/something", http.NoBody)
assert.NoError(t, err)
req.Header.Add("X-Forwarded-For", "2001:db8::ff00:42:8329,::1,fc00::")
adr, err := GetRealIP(req)
require.NoError(t, err)
assert.Equal(t, "2001:db8::ff00:42:8329", adr)
})

t.Run("RemoteAddr IPv6 fallback", func(t *testing.T) {
req, err := http.NewRequest("GET", "/something", http.NoBody)
assert.NoError(t, err)
req.RemoteAddr = "[2001:db8::ff00:42:8329]:1234"
adr, err := GetRealIP(req)
require.NoError(t, err)
assert.Equal(t, "2001:db8::ff00:42:8329", adr)
})
}

func TestGetFromRemoteAddr(t *testing.T) {
ts := httptest.NewServer(http.HandlerFunc(func(_ http.ResponseWriter, r *http.Request) {
log.Printf("%v", r)
adr, err := GetRealIP(r)
require.NoError(t, err)
assert.Equal(t, "127.0.0.1", adr)
}))

req, err := http.NewRequest("GET", ts.URL+"/something", http.NoBody)
require.NoError(t, err)
client := http.Client{Timeout: time.Second}
_, err = client.Do(req)
require.NoError(t, err)
}
Loading