Add drafty skeleton

1 files changed, 217 insertions, 0 deletions

diff --git a/main.go b/main.go
new file mode 100644
index 0000000..a68da1e
--- /dev/null
+++ b/main.go
@@ -0,0 +1,217 @@
+package main
+
+import (
+	"bufio"
+	"context"
+	"log"
+	logger "log"
+	"net/http"
+	"os"
+	"os/signal"
+	"sync"
+	"syscall"
+	"time"
+
+	"git.cs.kau.se/rasmoste/find-onion/internal/onionloc"
+	"git.cs.kau.se/rasmoste/find-onion/internal/options"
+)
+
+type match struct {
+	dnsName    string
+	onionName  string
+	httpHeader bool
+	htmlAttr   bool
+}
+
+func main() {
+	opts := options.Parse()
+	cli := &http.Client{
+		Transport: &http.Transport{
+			DisableKeepAlives: true,
+		},
+	}
+
+	// sanCh is a channel of names that our workers should visit
+	sanCh := make(chan string, 2*opts.NumWorkers)
+	defer close(sanCh)
+
+	// matchCh is a channel of matches, i.e., sites that had Onion-Location
+	matchCh := make(chan match, 2*opts.NumWorkers)
+	defer close(matchCh)
+
+	// missCh is a channel of misses, i.e., the number of sites that had not
+	// configured Onion-Location.  True means HTTP GET succeeded.
+	missCh := make(chan bool, 2*opts.NumWorkers)
+	defer close(missCh)
+
+	var wg sync.WaitGroup
+	defer wg.Wait()
+	ctx, cancel := context.WithCancel(context.Background())
+
+	defer log.Printf("INFO: completed")
+	log.Printf("INFO: starting await handler, ctrl+C to exit\n")
+	go func() {
+		wg.Add(1)
+		defer wg.Done()
+		await(ctx, cancel)
+	}()
+
+	log.Printf("INFO: starting %d workers\n", opts.NumWorkers)
+	for i := 0; i < opts.NumWorkers; i++ {
+		go func() {
+			wg.Add(1)
+			defer wg.Done()
+			workHandler(ctx, opts, cli, sanCh, matchCh, missCh)
+		}()
+	}
+
+	log.Printf("INFO: starting work receiver\n")
+	go func() {
+		wg.Add(1)
+		defer wg.Done()
+		workAggregator(ctx, cancel, opts, matchCh, missCh)
+	}()
+
+	log.Printf("INFO: generating work\n")
+	workGenerator(ctx, cancel, opts, sanCh)
+	time.Sleep(time.Second)
+
+	defer cancel()
+	for {
+		select {
+		case <-ctx.Done():
+			logger.Printf("DEBUG: context cancelled, exiting...\n")
+			return
+		case <-time.After(1 * time.Second):
+		}
+
+		numMessages := len(sanCh) + len(matchCh) + len(missCh)
+		if numMessages == 0 {
+			logger.Printf("Exit scheduled in %v from now", 2*opts.Timeout)
+			time.Sleep(2 * opts.Timeout)
+			return // TODO: fix a cleaner exit
+		}
+		logger.Printf("DEBUG: waiting for %d messages to be processed before exit", numMessages)
+	}
+}
+
+func await(ctx context.Context, cancel context.CancelFunc) {
+	sigs := make(chan os.Signal, 1)
+	defer close(sigs)
+
+	signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
+	select {
+	case <-sigs:
+		cancel()
+	case <-ctx.Done():
+	}
+}
+
+func workHandler(ctx context.Context, opts options.Options, cli *http.Client,
+	sanCh chan string, matchCh chan match, missCh chan bool) {
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case san := <-sanCh:
+			func() {
+				cctx, cancel := context.WithTimeout(ctx, opts.Timeout)
+				defer cancel()
+
+				req, err := http.NewRequestWithContext(cctx, http.MethodGet, "https://"+san, nil)
+				if err != nil {
+					logger.Printf("DEBUG: %s: %v", san, err)
+					return
+				}
+
+				rsp, err := cli.Do(req)
+				if err != nil {
+					missCh <- false
+					return
+				}
+				defer rsp.Body.Close()
+
+				v, ok := onionloc.HTTP(rsp)
+				if ok {
+					matchCh <- match{dnsName: san, onionName: v, httpHeader: true}
+					return
+				}
+				v, ok = onionloc.HTML(rsp)
+				if ok {
+					matchCh <- match{dnsName: san, onionName: v, htmlAttr: true}
+					return
+				}
+				missCh <- true
+			}()
+		}
+	}
+}
+
+func workAggregator(ctx context.Context, _ context.CancelFunc, opts options.Options, matchCh chan match, missCh chan bool) {
+	ticker := time.NewTicker(opts.MetricsInterval)
+	defer ticker.Stop()
+
+	numConnected := 0
+	numOnionLocation := 0
+	numVisits := 0
+	output := func() {
+		logger.Printf("INFO: %d/%d connected, %d matched\n", numConnected, numVisits, numOnionLocation)
+	}
+	defer output()
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case m := <-matchCh:
+			numVisits += 1
+			numConnected += 1
+			numOnionLocation += 1
+
+			log.Printf("INFO: found match %s (HTTP:%v HTML:%v)\n", m.dnsName, m.httpHeader, m.htmlAttr)
+		case connected := <-missCh:
+			numVisits += 1
+			if connected {
+				numConnected += 1
+			}
+		case <-ticker.C:
+			output()
+		}
+	}
+}
+
+func workGenerator(ctx context.Context, cancel context.CancelFunc, opts options.Options, sanCh chan string) {
+	fp, err := os.OpenFile(opts.InputFile, os.O_RDONLY, 0644)
+	if err != nil {
+		logger.Printf("ERROR: %v", err)
+		cancel()
+		return
+	}
+
+	defer fp.Close()
+	scanner := bufio.NewScanner(fp)
+	max := 1024 * 1024
+	buf := make([]byte, 0, max)
+	scanner.Buffer(buf, max)
+
+	for scanner.Scan() {
+		select {
+		case <-ctx.Done():
+			return
+		default:
+		}
+
+		for {
+			if len(sanCh) < cap(sanCh) {
+				sanCh <- scanner.Text()
+				break
+			}
+			select {
+			case <-ctx.Done():
+				return
+			case <-time.After(time.Second):
+				continue
+			}
+		}
+	}
+}