dnsforward: imp err msg, docs

heyxkhoa · Jul 28, 2022 · ea2272d · ea2272d
1 parent fd9ee82
commit ea2272d
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Showing 2 changed files with 22 additions and 8 deletions.
diff --git a/internal/dnsforward/http.go b/internal/dnsforward/http.go
@@ -374,7 +374,7 @@ func newUpstreamConfig(upstreams []string) (conf *proxy.UpstreamConfig, err erro
 
 		_, err = validateUpstream(ups, domains)
 		if err != nil {
-			return nil, fmt.Errorf("validating the upstream %s: %w", u, err)
+			return nil, fmt.Errorf("validating upstream %s: %w", u, err)
 		}
 	}
 
@@ -526,13 +526,19 @@ type excFunc func(u upstream.Upstream) (err error)
 
 // checkDNSUpstreamExc checks if the DNS upstream exchanges correctly.
 func checkDNSUpstreamExc(u upstream.Upstream) (err error) {
+	// testTLD is the special-use fully-qualified domain name for testing the
+	// DNS server reachability.
+	//
+	// See https://datatracker.ietf.org/doc/html/rfc6761#section-6.2.
+	const testTLD = "test."
+
 	req := &dns.Msg{
 		MsgHdr: dns.MsgHdr{
 			Id:               dns.Id(),
 			RecursionDesired: true,
 		},
 		Question: []dns.Question{{
-			Name:   "test.",
+			Name:   testTLD,
 			Qtype:  dns.TypeA,
 			Qclass: dns.ClassINET,
 		}},
@@ -551,14 +557,22 @@ func checkDNSUpstreamExc(u upstream.Upstream) (err error) {
 
 // checkPrivateUpstreamExc checks if the upstream for resolving private
 // addresses exchanges correctly.
+//
+// TODO(e.burkov):  Think on testing the ip6.arpa. as well.
 func checkPrivateUpstreamExc(u upstream.Upstream) (err error) {
+	// inAddrArpaTLD is the special-use fully-qualified domain name for PTR IP
+	// address resolution.
+	//
+	// See https://datatracker.ietf.org/doc/html/rfc1035#section-3.5.
+	const inAddrArpaTLD = "in-addr.arpa."
+
 	req := &dns.Msg{
 		MsgHdr: dns.MsgHdr{
 			Id:               dns.Id(),
 			RecursionDesired: true,
 		},
 		Question: []dns.Question{{
-			Name:   "in-addr.arpa.",
+			Name:   inAddrArpaTLD,
 			Qtype:  dns.TypePTR,
 			Qclass: dns.ClassINET,
 		}},

diff --git a/internal/dnsforward/http_test.go b/internal/dnsforward/http_test.go
@@ -186,7 +186,7 @@ func TestDNSForwardHTTP_handleSetConfig(t *testing.T) {
 	}, {
 		name: "upstream_dns_bad",
 		wantSet: `validating upstream servers: ` +
-			`validating the upstream !!!: bad ipport address "!!!": ` +
+			`validating upstream !!!: bad ipport address "!!!": ` +
 			`address !!!: missing port in address`,
 	}, {
 		name: "bootstraps_bad",
@@ -293,23 +293,23 @@ func TestValidateUpstreams(t *testing.T) {
 		},
 	}, {
 		name:    "invalid",
-		wantErr: `validating the upstream dhcp://fake.dns: wrong protocol`,
+		wantErr: `validating upstream dhcp://fake.dns: wrong protocol`,
 		set:     []string{"dhcp://fake.dns"},
 	}, {
 		name:    "invalid",
-		wantErr: `validating the upstream 1.2.3.4.5: bad ipport address "1.2.3.4.5": address 1.2.3.4.5: missing port in address`,
+		wantErr: `validating upstream 1.2.3.4.5: bad ipport address "1.2.3.4.5": address 1.2.3.4.5: missing port in address`,
 		set:     []string{"1.2.3.4.5"},
 	}, {
 		name:    "invalid",
-		wantErr: `validating the upstream 123.3.7m: bad ipport address "123.3.7m": address 123.3.7m: missing port in address`,
+		wantErr: `validating upstream 123.3.7m: bad ipport address "123.3.7m": address 123.3.7m: missing port in address`,
 		set:     []string{"123.3.7m"},
 	}, {
 		name:    "invalid",
 		wantErr: `bad upstream for domain "[/host.com]tls://dns.adguard.com": missing separator`,
 		set:     []string{"[/host.com]tls://dns.adguard.com"},
 	}, {
 		name:    "invalid",
-		wantErr: `validating the upstream [host.ru]#: bad ipport address "[host.ru]#": address [host.ru]#: missing port in address`,
+		wantErr: `validating upstream [host.ru]#: bad ipport address "[host.ru]#": address [host.ru]#: missing port in address`,
 		set:     []string{"[host.ru]#"},
 	}, {
 		name:    "valid_default",