WIP: cf IP scanner

src/github.com/getlantern/cfscanner/cfscanner.go

@@ -0,0 +1,129 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net"
+	"net/http"
+	"os"
+	"strings"
+	"sync"
+)
+
+var (
+	help       = flag.Bool("help", false, "Get usage help")
+	numWorkers = flag.Int("workers", 1, "Number of concurrent workers")
+)
+
+func webSlurp(url string) (string, error) {
+	resp, err := http.Get(url)
+	if err != nil {
+		return "", fmt.Errorf("Error fetching IP list: %v", err)
+	}
+	defer resp.Body.Close()
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return "", fmt.Errorf("Error trying to read response: %v", err)
+	}
+	return string(body), nil
+}
+
+type masquerade struct {
+	Domain    string
+	IpAddress string
+	RootCA    *castat
+}
+
+type castat struct {
+	CommonName string
+	Cert       string
+	freq       float64
+}
+
+func main() {
+	flag.Parse()
+
+	if *help {
+		flag.Usage()
+		os.Exit(1)
+	}
+
+	s, err := webSlurp("https://www.cloudflare.com/ips-v4")
+	if err != nil {
+		log.Fatal(err)
+	}
+	ipch := make(chan string)
+	ipwg := sync.WaitGroup{}
+	lines := strings.Split(s, "\n")
+	ipwg.Add(len(lines))
+	for _, line := range lines {
+		go enumerateRange(line, ipch, &ipwg)
+	}
+
+	// Send death pill to all workers when we're done feeding IPs.
+	go func() {
+		ipwg.Wait()
+		for i := 0; i < *numWorkers; i++ {
+			ipch <- ""
+		}
+	}()
+
+	reswg := sync.WaitGroup{}
+	reswg.Add(*numWorkers)
+	resch := make(chan *masquerade)
+	go func() {
+		reswg.Wait()
+		resch <- nil
+	}()
+	for i := 0; i < *numWorkers; i++ {
+		go checkIPs(ipch, resch, &reswg)
+	}
+	for m := range resch {
+		if m == nil {
+			break
+		}
+		fmt.Println("Now I would merge CAs and save", m)
+	}
+}
+
+func checkIPs(ipch <-chan string, resch chan<- *masquerade, wg *sync.WaitGroup) {
+	defer wg.Done()
+	for ip := range ipch {
+		if ip == "" {
+			break
+		}
+		m := checkIP(ip)
+		if m != nil {
+			resch <- m
+		}
+	}
+}
+
+func checkIP(ip string) *masquerade {
+	fmt.Println("Now I would check whether the IP can be fronted to, and get a domain and CA for it.")
+	return &masquerade{}
+}
+
+func enumerateRange(cidr string, ch chan<- string, wg *sync.WaitGroup) {
+	defer wg.Done()
+	ip, ipnet, err := net.ParseCIDR(cidr)
+	if err != nil {
+		log.Fatal(err)
+	}
+	for ip := ip.Mask(ipnet.Mask); ipnet.Contains(ip); inc(ip) {
+		if ip.IsGlobalUnicast() {
+			ch <- ip.String()
+		}
+	}
+}
+
+func inc(ip net.IP) {
+	for j := len(ip) - 1; j >= 0; j-- {
+		ip[j]++
+		if ip[j] > 0 {
+			break
+		}
+	}
+}