Ignore a negative decided precedence instead of wrapping it (#707)

Signed-off-by: Arrobo, Gabriel <gabriel.arrobo@intel.com>

Author: gab-arrobo

producer/callback.go

@@ -573,10 +573,16 @@ func requalifyRule(smContext *smfContext.SMContext, pfcpParam *pfcpParam, node *
 			tcRef = rule.RefTcData[0]
 		}
 		if decided, ok := rule.GetPrecedenceOk(); ok {
-			// Zero is the top of the order. The SMF reads a PDR's zero as unset, so it is
-			// programmed as 1, as an added rule's is.
-			value := max(uint32(*decided), 1)
-			precedence = &value
+			if *decided < 0 {
+				// Out of the range of an unsigned PDR precedence: converted, it would wrap to about
+				// 4 billion and put the rule last. Left out, so the PDR keeps the one it has.
+				logger.PduSessLog.Warnf("PCC rule %s: ignoring the negative precedence %d", name, *decided)
+			} else {
+				// Zero is the top of the order. The SMF reads a PDR's zero as unset, so it is
+				// programmed as 1, as an added rule's is.
+				value := max(uint32(*decided), 1)
+				precedence = &value
+			}
 		}
 	}
 

producer/policy_update_rule_mapping_test.go

@@ -2361,3 +2361,26 @@ func TestAnAddedUplinkPDRNamesTheInstalledFTEID(t *testing.T) {
 		t.Error("the added uplink PDR was sent with no F-TEID")
 	}
 }
+
+// A negative decided precedence is outside a PDR's unsigned range: converted, it wrapped to about 4
+// billion and put the rule last. It is ignored, and the PDR keeps the precedence it has.
+func TestANegativeDecidedPrecedenceLeavesThePDRsPrecedence(t *testing.T) {
+	s := newTwoRuleSession(t, false)
+	s.cirUL.Precedence, s.cirDL.Precedence = 200, 200
+	decision := s.rateChange()
+	rule := decision.PccRules[cirRuleID]
+	rule.Precedence = openapi.PtrInt32(-5)
+	decision.PccRules[cirRuleID] = rule
+	s.sm.SmPolicyUpdates = []*qos.PolicyUpdate{qos.BuildSmPolicyUpdate(&s.sm.SmPolicyData, decision)}
+
+	param := BuildPfcpParam(s.sm)
+	if len(param.unbuilt) != 0 {
+		t.Fatalf("not built: %v", param.unbuilt)
+	}
+	if !param.touches(s.cirUL) || !param.touches(s.cirDL) {
+		t.Fatal("the rule's PDRs were not updated")
+	}
+	if s.cirUL.Precedence != 200 || s.cirDL.Precedence != 200 {
+		t.Errorf("precedences are %d and %d, want the 200 the PDRs had", s.cirUL.Precedence, s.cirDL.Precedence)
+	}
+}