all: imp client resolving

internal/home/clientaddr.go

@@ -0,0 +1,146 @@
+package home
+
+import (
+	"context"
+	"net/netip"
+	"time"
+
+	"github.com/AdguardTeam/AdGuardHome/internal/rdns"
+	"github.com/AdguardTeam/AdGuardHome/internal/whois"
+	"github.com/AdguardTeam/golibs/log"
+)
+
+// TODO(a.garipov): It is currently hard to add tests for this structure due to
+// strong coupling between it and Context.dnsServer with Context.clients.
+// Resolve this coupling and add proper testing.
+
+// clientAddrProcessor processes incoming client addresses with rDNS and WHOIS,
+// if configured.
+type clientAddrProcessor struct {
+	rdns  rdns.Interface
+	whois whois.Interface
+}
+
+const (
+	// defaultQueueSize is the size of queue of IPs for rDNS and WHOIS
+	// processing.
+	defaultQueueSize = 255
+
+	// defaultCacheSize is the maximum size of the cache for rDNS and WHOIS
+	// processing.  It must be greater than zero.
+	defaultCacheSize = 10_000
+
+	// defaultIPTTL is the Time to Live duration for IP addresses cached by
+	// rDNS and WHOIS.
+	defaultIPTTL = 1 * time.Hour
+)
+
+// newClientAddrProcessor returns a new client address processor.  c must not be
+// nil.
+func newClientAddrProcessor(c *clientSourcesConfig) (p *clientAddrProcessor) {
+	p = &clientAddrProcessor{}
+
+	if c.RDNS {
+		p.rdns = rdns.New(&rdns.Config{
+			Exchanger: Context.dnsServer,
+			CacheSize: defaultCacheSize,
+			CacheTTL:  defaultIPTTL,
+		})
+	} else {
+		p.rdns = rdns.Empty{}
+	}
+
+	if c.WHOIS {
+		// TODO(s.chzhen):  Consider making configurable.
+		const (
+			// defaultTimeout is the timeout for WHOIS requests.
+			defaultTimeout = 5 * time.Second
+
+			// defaultMaxConnReadSize is an upper limit in bytes for reading from a
+			// net.Conn.
+			defaultMaxConnReadSize = 64 * 1024
+
+			// defaultMaxRedirects is the maximum redirects count.
+			defaultMaxRedirects = 5
+
+			// defaultMaxInfoLen is the maximum length of whois.Info fields.
+			defaultMaxInfoLen = 250
+		)
+
+		p.whois = whois.New(&whois.Config{
+			DialContext:     customDialContext,
+			ServerAddr:      whois.DefaultServer,
+			Port:            whois.DefaultPort,
+			Timeout:         defaultTimeout,
+			CacheSize:       defaultCacheSize,
+			MaxConnReadSize: defaultMaxConnReadSize,
+			MaxRedirects:    defaultMaxRedirects,
+			MaxInfoLen:      defaultMaxInfoLen,
+			CacheTTL:        defaultIPTTL,
+		})
+	} else {
+		p.whois = whois.Empty{}
+	}
+
+	return p
+}
+
+// process processes the incoming client IP-address information.  It is intended
+// to be used as a goroutine.
+func (p *clientAddrProcessor) process(clientIPs <-chan netip.Addr) {
+	defer log.OnPanic("clientAddrProcessor.process")
+
+	log.Info("home: processing client addresses")
+
+	for ip := range clientIPs {
+		p.processRDNS(ip)
+		p.processWHOIS(ip)
+	}
+
+	log.Info("home: finished processing client addresses")
+}
+
+// processRDNS resolves the clients' IP addresses using reverse DNS.
+func (p *clientAddrProcessor) processRDNS(ip netip.Addr) {
+	start := time.Now()
+	log.Debug("home: processing client %s with rdns", ip)
+	defer func() {
+		log.Debug("home: finished processing client %s with rdns in %s", ip, time.Since(start))
+	}()
+
+	ok := Context.dnsServer.ShouldResolveClient(ip)
+	if !ok {
+		return
+	}
+
+	host, changed := p.rdns.Process(ip)
+	if host == "" || !changed {
+		return
+	}
+
+	ok = Context.clients.AddHost(ip, host, ClientSourceRDNS)
+	if ok {
+		return
+	}
+
+	log.Debug("dns: setting rdns info for client %q: already set with higher priority source", ip)
+}
+
+// processWHOIS looks up the information aobut clients' IP addresses in the
+// WHOIS databases.
+func (p *clientAddrProcessor) processWHOIS(ip netip.Addr) {
+	start := time.Now()
+	log.Debug("home: processing client %s with whois", ip)
+	defer func() {
+		log.Debug("home: finished processing client %s with whois in %s", ip, time.Since(start))
+	}()
+
+	// TODO(s.chzhen):  Move the timeout logic from WHOIS configuration to the
+	// context.
+	info, changed := p.whois.Process(context.Background(), ip)
+	if info == nil || !changed {
+		return
+	}
+
+	Context.clients.setWHOISInfo(ip, info)
+}