switches: bug fix with bridge names

Autogenerated bridge names would sometimes not work at all, just because the names weren't compliant. Made a digest function to make unique bridge names but compliant with the linux interfaces api

src/switch/cmd/ned-server/main.go

@@ -2,7 +2,6 @@ package main
 
 import (
 	"context"
-	"errors"
 	"flag"
 	"fmt"
 	"log"
@@ -18,6 +17,11 @@ import (
 	"l2sm.local/ovs-switch/internal/inits"
 	"l2sm.local/ovs-switch/pkg/nedpb"
 	"l2sm.local/ovs-switch/pkg/ovs"
+	"l2sm.local/ovs-switch/pkg/utils"
+)
+
+const (
+	DEFAULT_CONFIG_PATH = "/etc/l2sm"
 )
 
 // server is used to implement nedpb.VxlanServiceServer
@@ -45,7 +49,8 @@ func main() {
 
 	fmt.Println("Initializing switch, connected to controller: ", settings.ControllerIP)
 
-	bridge, err := inits.InitializeSwitch(settings.NedName, settings.ControllerIP)
+	nedBridgeName, _ := utils.GenerateBridgeName(settings.NedName)
+	bridge, err := inits.InitializeSwitch(nedBridgeName, settings.ControllerIP)
 	if err != nil {
 		log.Fatalf("error initializing ned: %v", err)
 	}
@@ -158,17 +163,10 @@ func AddInterfaceToBridge(bridgeName string) (string, error) {
 
 func takeArguments() (string, string, error) {
 
-	configDir := flag.String("config_dir", "", "directory where the ned settings are specified. Required")
-	neighborsDir := flag.String("neighbors_dir", "", "directory where the ned's neighbors  are specified. Required")
+	configDir := flag.String("config_dir", fmt.Sprintf("%s/config.json", DEFAULT_CONFIG_PATH), "directory where the ned settings are specified. Required")
+	neighborsDir := flag.String("neighbors_dir", fmt.Sprintf("%s/neighbors.json", DEFAULT_CONFIG_PATH), "directory where the ned's neighbors  are specified. Required")
 
 	flag.Parse()
 
-	switch {
-	case *configDir == "":
-		return "", "", errors.New("config directory is not defined")
-	case *neighborsDir == "":
-		return "", "", errors.New("provider name is not defined")
-	}
-
 	return *configDir, *neighborsDir, nil
 }

src/switch/pkg/utils/utils.go

+package utils
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
+)
+
+func GenerateBridgeName(uniqueIdentifier string) (string, error) {
+	// Create a SHA-256 hash of the input string
+	hash := sha256.New()
+	_, err := hash.Write([]byte(uniqueIdentifier))
+	if err != nil {
+		return "", err
+	}
+	// Get the full hashed value in hex format
+	fullHash := hex.EncodeToString(hash.Sum(nil))
+
+	// Truncate to the first 5 characters of the hash
+	digestedName := fullHash[:5]
+
+	// Return the formatted bridge name
+	return fmt.Sprintf("br-%s", digestedName), nil
+}