Adding support to provide DNS server port (#378)

* Adding support to provide DNS server port * Resolve issues with Wheezy docker builds * Updating to match that of Travis and docker hub images * Fix up broken logic for DNS server w/ port * Updateing/Adding inetgration tests and unit tests for DNS Querying
goss-org · Dec 18, 2019 · 584b0f1 · 584b0f1
1 parent c8cd87b
commit 584b0f1
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Showing 3 changed files with 46 additions and 11 deletions.
diff --git a/integration-tests/goss/goss-shared.yaml b/integration-tests/goss/goss-shared.yaml
@@ -99,14 +99,14 @@ dns:
     addrs:
     - 192.30.252.153
     timeout: 2000
-    server: 8.8.8.8
+    server: 8.8.8.8:53
   MX:dnstest.io:
     resolvable: true
     addrs:
     - 10 b.dnstest.io.
     - 5 a.dnstest.io.
     timeout: 2000
-    server: 8.8.8.8
+    server: 8.8.8.8:53
   NS:dnstest.io:
     resolvable: true
     addrs:

diff --git a/system/dns.go b/system/dns.go
@@ -174,7 +174,7 @@ func LookupHost(host string, server string, c *dns.Client, m *dns.Msg) (addrs []
 // A record lookup
 func LookupA(host string, server string, c *dns.Client, m *dns.Msg) (addrs []string, err error) {
 	m.SetQuestion(dns.Fqdn(host), dns.TypeA)
-	r, _, err := c.Exchange(m, net.JoinHostPort(server, "53"))
+	r, _, err := c.Exchange(m, parseServerString(server))
 	if err != nil {
 		return nil, err
 	}
@@ -188,10 +188,20 @@ func LookupA(host string, server string, c *dns.Client, m *dns.Msg) (addrs []str
 	return
 }
 
+// parseServerString - Check if the DNS Server in server config has a port, if not ensure 53 is prefixed.
+func parseServerString(server string) string {
+	srvhost, srvport, err := net.SplitHostPort(server)
+	if err != nil {
+		srvport = "53"
+		srvhost = server
+	}
+	return net.JoinHostPort(srvhost, srvport)
+}
+
 // AAAA (IPv6) record lookup
 func LookupAAAA(host string, server string, c *dns.Client, m *dns.Msg) (addrs []string, err error) {
 	m.SetQuestion(dns.Fqdn(host), dns.TypeAAAA)
-	r, _, err := c.Exchange(m, net.JoinHostPort(server, "53"))
+	r, _, err := c.Exchange(m, parseServerString(server))
 	if err != nil {
 		return nil, err
 	}
@@ -208,7 +218,7 @@ func LookupAAAA(host string, server string, c *dns.Client, m *dns.Msg) (addrs []
 // CNAME record lookup
 func LookupCNAME(host string, server string, c *dns.Client, m *dns.Msg) (addrs []string, err error) {
 	m.SetQuestion(dns.Fqdn(host), dns.TypeCNAME)
-	r, _, err := c.Exchange(m, net.JoinHostPort(server, "53"))
+	r, _, err := c.Exchange(m, parseServerString(server))
 	if err != nil {
 		return nil, err
 	}
@@ -225,7 +235,7 @@ func LookupCNAME(host string, server string, c *dns.Client, m *dns.Msg) (addrs [
 // MX record lookup
 func LookupMX(host string, server string, c *dns.Client, m *dns.Msg) (addrs []string, err error) {
 	m.SetQuestion(dns.Fqdn(host), dns.TypeMX)
-	r, _, err := c.Exchange(m, net.JoinHostPort(server, "53"))
+	r, _, err := c.Exchange(m, parseServerString(server))
 	if err != nil {
 		return nil, err
 	}
@@ -243,7 +253,7 @@ func LookupMX(host string, server string, c *dns.Client, m *dns.Msg) (addrs []st
 // NS record lookup
 func LookupNS(host string, server string, c *dns.Client, m *dns.Msg) (addrs []string, err error) {
 	m.SetQuestion(dns.Fqdn(host), dns.TypeNS)
-	r, _, err := c.Exchange(m, net.JoinHostPort(server, "53"))
+	r, _, err := c.Exchange(m, parseServerString(server))
 	if err != nil {
 		return nil, err
 	}
@@ -260,7 +270,7 @@ func LookupNS(host string, server string, c *dns.Client, m *dns.Msg) (addrs []st
 // SRV record lookup
 func LookupSRV(host string, server string, c *dns.Client, m *dns.Msg) (addrs []string, err error) {
 	m.SetQuestion(dns.Fqdn(host), dns.TypeSRV)
-	r, _, err := c.Exchange(m, net.JoinHostPort(server, "53"))
+	r, _, err := c.Exchange(m, parseServerString(server))
 	if err != nil {
 		return nil, err
 	}
@@ -281,7 +291,7 @@ func LookupSRV(host string, server string, c *dns.Client, m *dns.Msg) (addrs []s
 // TXT record lookup
 func LookupTXT(host string, server string, c *dns.Client, m *dns.Msg) (addrs []string, err error) {
 	m.SetQuestion(dns.Fqdn(host), dns.TypeTXT)
-	r, _, err := c.Exchange(m, net.JoinHostPort(server, "53"))
+	r, _, err := c.Exchange(m, parseServerString(server))
 	if err != nil {
 		return nil, err
 	}
@@ -305,7 +315,7 @@ func LookupPTR(addr string, server string, c *dns.Client, m *dns.Msg) (name []st
 
 	m.SetQuestion(reverse, dns.TypePTR)
 
-	r, _, err := c.Exchange(m, net.JoinHostPort(server, "53"))
+	r, _, err := c.Exchange(m, parseServerString(server))
 	if err != nil {
 		return nil, err
 	}
@@ -320,7 +330,7 @@ func LookupPTR(addr string, server string, c *dns.Client, m *dns.Msg) (name []st
 // CAA record lookup
 func LookupCAA(host string, server string, c *dns.Client, m *dns.Msg) (addrs []string, err error) {
 	m.SetQuestion(dns.Fqdn(host), dns.TypeCAA)
-	r, _, err := c.Exchange(m, net.JoinHostPort(server, "53"))
+	r, _, err := c.Exchange(m, parseServerString(server))
 	if err != nil {
 		return nil, err
 	}

diff --git a/system/dns_test.go b/system/dns_test.go
@@ -0,0 +1,25 @@
+package system
+
+import (
+	"testing"
+)
+
+func TestparseServerString(t *testing.T) {
+
+	tables := []struct {
+		x string
+		n string
+	}{
+		{"127.0.0.1", "127.0.0.1:53"},
+		{"127.0.0.1:53", "127.0.0.1:53"},
+		{"127.0.0.1:8600", "127.0.0.1:8600"},
+		{"1.1.1.1:53", "1.1.1.1:53"},
+	}
+
+	for _, table := range tables {
+		output := parseServerString(table.x)
+		if output != table.n {
+			t.Errorf("parseServerString (%s) was incorrect, got: %s, want: %s.", table.x, output, table.n)
+		}
+	}
+}