GH-3798: A couple more PR updates

Test HTTP/DNS source IP without header/extra EDNS data.
Add WARN log for when prepared query with near=_ip is executed without specifying the source ip

agent/consul/prepared_query_endpoint.go

@@ -406,6 +406,11 @@ func (p *PreparedQuery) Execute(args *structs.PreparedQueryExecuteRequest,
 					break
 				}
 			}
+		} else {
+			p.srv.logger.Printf("[WARN] Prepared Query using near=_ip requires "+
+				"the source IP to be set but none was provided. No distance "+
+				"sorting will be done.")
+			
 		}
 		
 		// Either a source IP was given but we couldnt find the associated node

agent/dns_test.go

@@ -1890,7 +1890,7 @@ func TestDNS_PreparedQueryNearIP(t *testing.T) {
 		args := &structs.RegisterRequest{
 			Datacenter: "dc1",
 			Node:       "bar",
-			Address:    "198.18.0.9",
+			Address:    "127.0.0.1",
 		}
 		
 		var out struct{}
@@ -1937,7 +1937,7 @@ func TestDNS_PreparedQueryNearIP(t *testing.T) {
 		e.Family = 1
 		e.SourceNetmask = 32
 		e.SourceScope = 0
-		e.Address = net.ParseIP("198.18.0.9").To4()
+		e.Address = net.ParseIP("127.0.0.1").To4()
 		o.Option = append(o.Option, e)
 		m.Extra = append(m.Extra, o)
 		
@@ -1961,6 +1961,31 @@ func TestDNS_PreparedQueryNearIP(t *testing.T) {
 			}
 		}
 	})
+	
+	retry.Run(t, func(r *retry.R) {
+		m := new(dns.Msg)
+		m.SetQuestion("some.query.we.like.query.consul.", dns.TypeA)
+		
+		c := new(dns.Client)
+		in, _, err := c.Exchange(m, a.DNSAddr())
+		if err != nil {
+			r.Fatalf("Error with call to dns.Client.Exchange: %s", err)
+		}
+		
+		if len(serviceNodes) != len(in.Answer) {
+			r.Fatalf("Expecting %d A RRs in response, Actual found was %d", len(serviceNodes), len(in.Answer))
+		}
+		
+		for i, rr := range in.Answer {
+			if aRec, ok := rr.(*dns.A); ok {
+				if actual := aRec.A.String(); serviceNodes[i].address != actual {
+					r.Fatalf("Expecting A RR #%d = %s, Actual RR was %s", i, serviceNodes[i].address, actual)
+				}
+			} else {
+				r.Fatalf("DNS Answer contained a non-A RR")
+			}
+		}
+	})
 }
 
 func TestDNS_ServiceLookup_PreparedQueryNamePeriod(t *testing.T) {

agent/prepared_query_endpoint_test.go

@@ -380,6 +380,24 @@ func TestPreparedQuery_Execute(t *testing.T) {
 		if r.Failovers != 99 {
 			t.Fatalf("bad: %v", r)
 		}
+		
+		req, _ = http.NewRequest("GET", "/v1/query/my-id/execute?token=my-token&consistent=true&near=_ip&limit=5", body)
+		req.RemoteAddr = "127.0.0.1:12345"
+		resp = httptest.NewRecorder()
+		obj, err = a.srv.PreparedQuerySpecific(resp, req)
+		if err != nil {
+			t.Fatalf("err: %v", err)
+		}
+		if resp.Code != 200 {
+			t.Fatalf("bad code: %d", resp.Code)
+		}
+		r, ok = obj.(structs.PreparedQueryExecuteResponse)
+		if !ok {
+			t.Fatalf("unexpected: %T", obj)
+		}
+		if r.Failovers != 99 {
+			t.Fatalf("bad: %v", r)
+		}
 	})
 
 	// Ensure the proper params are set when no special args are passed