Distance support : Impossible travel (#2108)

* add distance helpers

go.mod

@@ -173,6 +173,7 @@ require (
 	github.com/tklauser/go-sysconf v0.3.11 // indirect
 	github.com/tklauser/numcpus v0.6.0 // indirect
 	github.com/ugorji/go/codec v1.2.6 // indirect
+	github.com/umahmood/haversine v0.0.0-20151105152445-808ab04add26 // indirect
 	github.com/vjeantet/grok v1.0.1 // indirect
 	github.com/vmihailenco/msgpack v4.0.4+incompatible // indirect
 	github.com/yusufpapurcu/wmi v1.2.2 // indirect

go.sum

@@ -921,6 +921,8 @@ github.com/ugorji/go v1.2.6/go.mod h1:anCg0y61KIhDlPZmnH+so+RQbysYVyDko0IMgJv0Nn
 github.com/ugorji/go/codec v1.1.7/go.mod h1:Ax+UKWsSmolVDwsd+7N3ZtXu+yMGCf907BLYF3GoBXY=
 github.com/ugorji/go/codec v1.2.6 h1:7kbGefxLoDBuYXOms4yD7223OpNMMPNPZxXk5TvFcyQ=
 github.com/ugorji/go/codec v1.2.6/go.mod h1:V6TCNZ4PHqoHGFZuSG1W8nrCzzdgA2DozYxWFFpvxTw=
+github.com/umahmood/haversine v0.0.0-20151105152445-808ab04add26 h1:UFHFmFfixpmfRBcxuu+LA9l8MdURWVdVNUHxO5n1d2w=
+github.com/umahmood/haversine v0.0.0-20151105152445-808ab04add26/go.mod h1:IGhd0qMDsUa9acVjsbsT7bu3ktadtGOHI79+idTew/M=
 github.com/vektah/gqlparser v1.1.2/go.mod h1:1ycwN7Ij5njmMkPPAOaRFY4rET2Enx7IkVv3vaXspKw=
 github.com/vjeantet/grok v1.0.1 h1:2rhIR7J4gThTgcZ1m2JY4TrJZNgjn985U28kT2wQrJ4=
 github.com/vjeantet/grok v1.0.1/go.mod h1:ax1aAchzC6/QMXMcyzHQGZWaW1l195+uMYIkCWPCNIo=

pkg/exprhelpers/exprlib.go

@@ -19,6 +19,8 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 	log "github.com/sirupsen/logrus"
 
+	"github.com/umahmood/haversine"
+
 	"github.com/crowdsecurity/crowdsec/pkg/cache"
 	"github.com/crowdsecurity/crowdsec/pkg/database"
 	"github.com/crowdsecurity/crowdsec/pkg/types"
@@ -119,13 +121,51 @@ func GetExprEnv(ctx map[string]interface{}) map[string]interface{} {
 		"TrimPrefix":  strings.TrimPrefix,
 		"TrimSuffix":  strings.TrimSuffix,
 		"Get":         Get,
+		"Distance":    Distance,
 	}
 	for k, v := range ctx {
 		ExprLib[k] = v
 	}
 	return ExprLib
 }
 
+func Distance(lat1 string, long1 string, lat2 string, long2 string) (float64, error) {
+	lat1f, err := strconv.ParseFloat(lat1, 64)
+	if err != nil {
+		log.Warningf("lat1 is not a float : %v", err)
+		return 0, fmt.Errorf("lat1 is not a float : %v", err)
+	}
+	long1f, err := strconv.ParseFloat(long1, 64)
+	if err != nil {
+		log.Warningf("long1 is not a float : %v", err)
+		return 0, fmt.Errorf("long1 is not a float : %v", err)
+	}
+	lat2f, err := strconv.ParseFloat(lat2, 64)
+	if err != nil {
+		log.Warningf("lat2 is not a float : %v", err)
+
+		return 0, fmt.Errorf("lat2 is not a float : %v", err)
+	}
+	long2f, err := strconv.ParseFloat(long2, 64)
+	if err != nil {
+		log.Warningf("long2 is not a float : %v", err)
+
+		return 0, fmt.Errorf("long2 is not a float : %v", err)
+	}
+
+	//either set of coordinates is 0,0, return 0 to avoid FPs
+	if (lat1f == 0.0 && long1f == 0.0) || (lat2f == 0.0 && long2f == 0.0) {
+		log.Warningf("one of the coordinates is 0,0, returning 0")
+		return 0, nil
+	}
+
+	first := haversine.Coord{Lat: lat1f, Lon: long1f}
+	second := haversine.Coord{Lat: lat2f, Lon: long2f}
+
+	_, km := haversine.Distance(first, second)
+	return km, nil
+}
+
 func Init(databaseClient *database.Client) error {
 	dataFile = make(map[string][]string)
 	dataFileRegex = make(map[string][]*regexp.Regexp)

pkg/exprhelpers/exprlib_test.go

@@ -125,6 +125,22 @@ func TestVisitor(t *testing.T) {
 	}
 }
 
+func TestDistanceHelper(t *testing.T) {
+
+	//one set of coord is empty
+	ret, err := Distance("0.0", "0.0", "12.1", "12.1")
+	assert.NoError(t, err)
+	assert.Equal(t, 0.0, ret)
+	//those aren't even coords
+	ret, err = Distance("lol", "42.1", "12.1", "12.1")
+	assert.NotNil(t, err)
+	assert.Equal(t, 0.0, ret)
+	//real ones
+	ret, err = Distance("51.45", "1.15", "41.54", "12.27")
+	assert.NoError(t, err)
+	assert.Equal(t, 1389.1793118293067, ret)
+}
+
 func TestRegexpCacheBehavior(t *testing.T) {
 	err := Init(nil)
 	require.NoError(t, err)