[Network Path] Fix parsing of query params (#24030)

* fix parsing of query params

* use mux test helper func

* fix linter error

cmd/system-probe/modules/traceroute.go

@@ -47,9 +47,8 @@ func (t *traceroute) Register(httpMux *module.Router) error {
 	// TODO: what other config should be passed as part of this request?
 	httpMux.HandleFunc("/traceroute/{host}", func(w http.ResponseWriter, req *http.Request) {
 		start := time.Now()
-		vars := mux.Vars(req)
 		id := getClientID(req)
-		cfg, err := parseParams(vars)
+		cfg, err := parseParams(req)
 		if err != nil {
 			log.Errorf("invalid params for host: %s: %s", cfg.DestHostname, err)
 			w.WriteHeader(http.StatusBadRequest)
@@ -99,17 +98,18 @@ func logTracerouteRequests(host string, client string, runCount uint64, start ti
 	}
 }
 
-func parseParams(vars map[string]string) (tracerouteutil.Config, error) {
+func parseParams(req *http.Request) (tracerouteutil.Config, error) {
+	vars := mux.Vars(req)
 	host := vars["host"]
-	port, err := parseUint(vars, "port", 16)
+	port, err := parseUint(req, "port", 16)
 	if err != nil {
 		return tracerouteutil.Config{}, fmt.Errorf("invalid port: %s", err)
 	}
-	maxTTL, err := parseUint(vars, "max_ttl", 8)
+	maxTTL, err := parseUint(req, "max_ttl", 8)
 	if err != nil {
 		return tracerouteutil.Config{}, fmt.Errorf("invalid max_ttl: %s", err)
 	}
-	timeout, err := parseUint(vars, "timeout", 32)
+	timeout, err := parseUint(req, "timeout", 32)
 	if err != nil {
 		return tracerouteutil.Config{}, fmt.Errorf("invalid timeout: %s", err)
 	}
@@ -122,10 +122,10 @@ func parseParams(vars map[string]string) (tracerouteutil.Config, error) {
 	}, nil
 }
 
-func parseUint(vars map[string]string, field string, bitSize int) (uint64, error) {
-	value, ok := vars[field]
-	if !ok {
-		return 0, nil
+func parseUint(req *http.Request, field string, bitSize int) (uint64, error) {
+	if req.URL.Query().Has(field) {
+		return strconv.ParseUint(req.URL.Query().Get(field), 10, bitSize)
 	}
-	return strconv.ParseUint(value, 10, bitSize)
+
+	return 0, nil
 }

cmd/system-probe/modules/traceroute_test.go

@@ -8,31 +8,36 @@
 package modules
 
 import (
+	"context"
+	"net/http"
+	"testing"
+
 	tracerouteutil "github.com/DataDog/datadog-agent/pkg/networkpath/traceroute"
+	"github.com/gorilla/mux"
 	"github.com/stretchr/testify/assert"
-	"testing"
+	"github.com/stretchr/testify/require"
 )
 
 func TestParseParams(t *testing.T) {
 	tests := []struct {
 		name           string
-		vars           map[string]string
+		host           string
+		params         map[string]string
 		expectedConfig tracerouteutil.Config
 		expectedError  string
 	}{
 		{
-			name: "only host",
-			vars: map[string]string{
-				"host": "1.2.3.4",
-			},
+			name:   "only host",
+			host:   "1.2.3.4",
+			params: map[string]string{},
 			expectedConfig: tracerouteutil.Config{
 				DestHostname: "1.2.3.4",
 			},
 		},
 		{
 			name: "all config",
-			vars: map[string]string{
-				"host":    "1.2.3.4",
+			host: "1.2.3.4",
+			params: map[string]string{
 				"port":    "42",
 				"max_ttl": "35",
 				"timeout": "1000",
@@ -47,7 +52,16 @@ func TestParseParams(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t1 *testing.T) {
-			config, err := parseParams(tt.vars)
+			req, err := http.NewRequestWithContext(context.Background(), "GET", "http://example.com", nil)
+			q := req.URL.Query()
+			for k, v := range tt.params {
+				q.Add(k, v)
+			}
+			req.URL.RawQuery = q.Encode()
+			req = mux.SetURLVars(req, map[string]string{"host": tt.host})
+
+			require.NoError(t, err)
+			config, err := parseParams(req)
 			assert.Equal(t, tt.expectedConfig, config)
 			if tt.expectedError != "" {
 				assert.EqualError(t, err, tt.expectedError)