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// Package cloudflare contains Cloudflare-related stuff.
package cloudflare
import (
"bufio"
"context"
"fmt"
"net/http"
"net/netip"
"os"
"strconv"
"strings"
"sync"
)
var iplistMu sync.Mutex
var iplist []netip.Prefix
//go:generate go run iplist_generate.go
// HasIP checks if ip is in a Cloudflare prefix.
func HasIP(ip netip.Addr) bool {
for _, p := range iplist {
if p.Contains(ip) {
return true
}
}
return false
}
// UpdateIPs updates the Cloudflare IP list.
func UpdateIPs(ctx context.Context) error {
var ps []netip.Prefix
for _, v := range []int{4, 6} {
if x, err := fetchIPs(ctx, "https://www.cloudflare.com/ips-v"+strconv.Itoa(v)); err == nil {
ps = append(ps, x...)
} else {
fmt.Fprintf(os.Stderr, "error: fetch ipv%d list: %v\n", v, err)
os.Exit(1)
}
}
iplistMu.Lock()
iplist = ps
iplistMu.Unlock()
return nil
}
func fetchIPs(ctx context.Context, u string) ([]netip.Prefix, error) {
req, err := http.NewRequestWithContext(ctx, http.MethodGet, u, nil)
if err != nil {
return nil, err
}
resp, err := http.DefaultClient.Do(req)
if err != nil {
return nil, err
}
defer resp.Body.Close()
if resp.StatusCode != http.StatusOK {
return nil, fmt.Errorf("response status %d (%s)", resp.StatusCode, resp.Status)
}
var r []netip.Prefix
s := bufio.NewScanner(resp.Body)
for s.Scan() {
if t := strings.TrimSpace(s.Text()); t != "" {
if strings.ContainsRune(t, '/') {
if x, err := netip.ParsePrefix(t); err == nil {
r = append(r, x)
} else {
return nil, fmt.Errorf("invalid prefix %q: %w", t, err)
}
} else {
if x, err := netip.ParseAddr(t); err == nil {
if p, err := x.Prefix(x.BitLen()); err == nil {
r = append(r, p)
} else {
panic(err)
}
} else {
return nil, fmt.Errorf("invalid ip %q: %w", t, err)
}
}
}
}
return r, s.Err()
}
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