comments and refactoring

19 files changed, 214 insertions, 52 deletions

diff --git a/cmd/vhost/main.go b/cmd/vhost/main.go
index dbf899a..26280ef 100644
--- a/cmd/vhost/main.go
+++ b/cmd/vhost/main.go
@@ -84,6 +84,16 @@ func main() {
 					ifaceName := line[3:]
 					ipstack.InterfaceUpREPL(ifaceName)
 				}
+			} else {
+				fmt.Println("Invalid command: ", line)
+				fmt.Println("Commands: ")
+				fmt.Println("  exit Terminate this program")
+				fmt.Println("    li List interfaces")
+				fmt.Println("    lr List routes")
+				fmt.Println("    ln List available neighbors")
+				fmt.Println("    up Enable an interface")
+				fmt.Println("  down Disable an interface")
+				fmt.Println("  send Send test packet")
 			}
 			continue
 		}
diff --git a/cmd/vrouter/main.go b/cmd/vrouter/main.go
index cde49a8..02104c5 100644
--- a/cmd/vrouter/main.go
+++ b/cmd/vrouter/main.go
@@ -10,57 +10,61 @@ import (
 )
 
 func main() {
+	// checks that a config file is passed as an argument
 	if len(os.Args) == 1 {
 		fmt.Printf("Usage:  %s <configFile>\n", os.Args[0])
 		os.Exit(1)
 	}
 
+	// get config file name from command line argument
 	fileName := os.Args[2]
 
+	// initialize the router with its config file
 	err := ipstack.Initialize(fileName)
 	if err != nil {
+		// return if there is an error
 		return
 	}
+
+	// register the test protocol
 	ipstack.RegisterProtocolHandler(ipstack.TEST_PROTOCOL)
+	// register the rip protocol for the router
 	ipstack.RegisterProtocolHandler(ipstack.RIP_PROTOCOL)
 
-	// TODO @ MICHAEL: Dont know why its not running instantly
-	//go func() {
-	//	for {
-	//		ipstack.RequestRip()
-	//		// takes time to compute I think
-	//		// TODO @ MICHAEL
-	//		time.Sleep(2 * time.Second)
-	//	}
-	//}()
-
-	// TODO @ MICHEAL
-	// go ipstack.CheckAndUpdateRoutingTable()
-
+	// create a scanner to read from stdin for command-line inputs
 	scanner := bufio.NewScanner(os.Stdin)
 
 	for scanner.Scan() {
 		line := scanner.Text()
 		switch line {
+		// print the interfaces
 		case "li":
 			fmt.Println("Name\tAddr/Prefix\tState")
 			fmt.Println(ipstack.SprintInterfaces())
+		// print the neighbors
 		case "ln":
-			fmt.Println("Iface\tVIP\tUDPAddr")
+			fmt.Println("Iface\tVIP\t\tUDPAddr")
 			fmt.Println(ipstack.SprintNeighbors())
+		// print the routing table
 		case "lr":
-			fmt.Println("T\tPrefix\tNext Hop\tCost")
+			fmt.Println("T\tPrefix\t\tNext Hop\tCost")
 			fmt.Println(ipstack.SprintRoutingTable())
+		// exit the program
 		case "q":
 			ipstack.CleanUp()
 			os.Exit(0)
+		case "exit":
+			ipstack.CleanUp()
+			os.Exit(0)
 		default:
 			if len(line) > 4 {
+				// disable an interface
 				if line[:4] == "down" {
 					ifaceName := line[5:]
 					ipstack.InterfaceDownREPL(ifaceName)
 				}
 
+				// attempts to send message to destination
 				if line[:4] == "send" {
 					// get IP address and message that follows it
 					IPAndMessage := strings.Split(line, " ")
@@ -71,15 +75,19 @@ func main() {
 					messageToSend := strings.Join(message, " ")
 					messageToSendBytes := []byte(messageToSend)
 
+					// get the longest prefix match for the destination
 					hop, err := ipstack.LongestPrefix(netip.MustParseAddr(ipAddr))
 					if err != nil {
 						fmt.Println(err)
 						continue
 					}
+					
 					myAddr := hop.Interface.IpPrefix.Addr()
+					// attempt to send the message to the destination
 					for _, neighbor := range ipstack.GetNeighbors()[hop.Interface.Name] {
 						if neighbor.VipAddr == netip.MustParseAddr(ipAddr) ||
 							neighbor.VipAddr == hop.VIP {
+							// send the message to the neighbor
 							bytesWritten, err := ipstack.SendIP(&myAddr, neighbor, ipstack.TEST_PROTOCOL, messageToSendBytes, ipAddr, nil)
 							if err != nil {
 								fmt.Println(err)
@@ -91,11 +99,22 @@ func main() {
 				}
 			}
 			if len(line) > 2 {
+				// enable an interface
 				if line[:2] == "up" {
 					// get interface name
 					ifaceName := line[3:]
 					ipstack.InterfaceUpREPL(ifaceName)
 				}
+			} else {
+				fmt.Println("Invalid command: ", line)
+				fmt.Println("Commands: ")
+				fmt.Println("  exit/q Terminate this program")
+				fmt.Println("    li List interfaces")
+				fmt.Println("    lr List routes")
+				fmt.Println("    ln List available neighbors")
+				fmt.Println("    up Enable an interface")
+				fmt.Println("  down Disable an interface")
+				fmt.Println("  send Send test packet")
 			}
 			continue
 		}
diff --git a/lnxfiles/doc-example/binaries.example.json b/lnxfiles/doc-example/binaries.example.json
new file mode 100644
index 0000000..b6ff6d9
--- /dev/null
+++ b/lnxfiles/doc-example/binaries.example.json
@@ -0,0 +1,17 @@
+{
+ "h1": {
+  "binary_path": "./vhost"
+ },
+ "h2": {
+  "binary_path": "./vhost"
+ },
+ "h3": {
+  "binary_path": "./vhost"
+ },
+ "r1": {
+  "binary_path": "./vrouter"
+ },
+ "r2": {
+  "binary_path": "./vrouter"
+ }
+}
\ No newline at end of file
diff --git a/lnxfiles/doc-example/nodes.json b/lnxfiles/doc-example/nodes.json
new file mode 100644
index 0000000..7b91355
--- /dev/null
+++ b/lnxfiles/doc-example/nodes.json
@@ -0,0 +1,7 @@
+{
+ "h1": "host",
+ "h2": "host",
+ "h3": "host",
+ "r1": "router",
+ "r2": "router"
+}
\ No newline at end of file
diff --git a/lnxfiles/loop/binaries.example.json b/lnxfiles/loop/binaries.example.json
new file mode 100644
index 0000000..3d0d853
--- /dev/null
+++ b/lnxfiles/loop/binaries.example.json
@@ -0,0 +1,23 @@
+{
+ "h1": {
+  "binary_path": "./vhost"
+ },
+ "h2": {
+  "binary_path": "./vhost"
+ },
+ "r1": {
+  "binary_path": "./vrouter"
+ },
+ "r2": {
+  "binary_path": "./vrouter"
+ },
+ "r3": {
+  "binary_path": "./vrouter"
+ },
+ "r4": {
+  "binary_path": "./vrouter"
+ },
+ "r5": {
+  "binary_path": "./vrouter"
+ }
+}
\ No newline at end of file
diff --git a/lnxfiles/loop/nodes.json b/lnxfiles/loop/nodes.json
new file mode 100644
index 0000000..2829f76
--- /dev/null
+++ b/lnxfiles/loop/nodes.json
@@ -0,0 +1,9 @@
+{
+ "h1": "host",
+ "h2": "host",
+ "r1": "router",
+ "r2": "router",
+ "r3": "router",
+ "r4": "router",
+ "r5": "router"
+}
\ No newline at end of file
diff --git a/lnxfiles/r1h2/binaries.example.json b/lnxfiles/r1h2/binaries.example.json
new file mode 100644
index 0000000..1888a6b
--- /dev/null
+++ b/lnxfiles/r1h2/binaries.example.json
@@ -0,0 +1,11 @@
+{
+ "h1": {
+  "binary_path": "./vhost"
+ },
+ "h2": {
+  "binary_path": "./vhost"
+ },
+ "r1": {
+  "binary_path": "./vrouter"
+ }
+}
\ No newline at end of file
diff --git a/lnxfiles/r1h2/nodes.json b/lnxfiles/r1h2/nodes.json
new file mode 100644
index 0000000..6accf5f
--- /dev/null
+++ b/lnxfiles/r1h2/nodes.json
@@ -0,0 +1,5 @@
+{
+ "h1": "host",
+ "h2": "host",
+ "r1": "router"
+}
\ No newline at end of file
diff --git a/lnxfiles/r1h4/binaries.example.json b/lnxfiles/r1h4/binaries.example.json
new file mode 100644
index 0000000..81dd521
--- /dev/null
+++ b/lnxfiles/r1h4/binaries.example.json
@@ -0,0 +1,17 @@
+{
+ "h1": {
+  "binary_path": "./vhost"
+ },
+ "h2": {
+  "binary_path": "./vhost"
+ },
+ "h3": {
+  "binary_path": "./vhost"
+ },
+ "h4": {
+  "binary_path": "./vhost"
+ },
+ "r1": {
+  "binary_path": "./vrouter"
+ }
+}
\ No newline at end of file
diff --git a/lnxfiles/r1h4/nodes.json b/lnxfiles/r1h4/nodes.json
new file mode 100644
index 0000000..1927005
--- /dev/null
+++ b/lnxfiles/r1h4/nodes.json
@@ -0,0 +1,7 @@
+{
+ "h1": "host",
+ "h2": "host",
+ "h3": "host",
+ "h4": "host",
+ "r1": "router"
+}
\ No newline at end of file
diff --git a/lnxfiles/r2h2/binaries.example.json b/lnxfiles/r2h2/binaries.example.json
new file mode 100644
index 0000000..59223ba
--- /dev/null
+++ b/lnxfiles/r2h2/binaries.example.json
@@ -0,0 +1,14 @@
+{
+ "h1": {
+  "binary_path": "./vhost"
+ },
+ "h2": {
+  "binary_path": "./vhost"
+ },
+ "r1": {
+  "binary_path": "./vrouter"
+ },
+ "r2": {
+  "binary_path": "./vrouter"
+ }
+}
\ No newline at end of file
diff --git a/lnxfiles/r2h2/nodes.json b/lnxfiles/r2h2/nodes.json
new file mode 100644
index 0000000..282ab86
--- /dev/null
+++ b/lnxfiles/r2h2/nodes.json
@@ -0,0 +1,6 @@
+{
+ "h1": "host",
+ "h2": "host",
+ "r1": "router",
+ "r2": "router"
+}
\ No newline at end of file
diff --git a/lnxfiles/r3h2/binaries.example.json b/lnxfiles/r3h2/binaries.example.json
new file mode 100644
index 0000000..9079242
--- /dev/null
+++ b/lnxfiles/r3h2/binaries.example.json
@@ -0,0 +1,17 @@
+{
+ "h1": {
+  "binary_path": "./vhost"
+ },
+ "h2": {
+  "binary_path": "./vhost"
+ },
+ "r1": {
+  "binary_path": "./vrouter"
+ },
+ "r2": {
+  "binary_path": "./vrouter"
+ },
+ "r3": {
+  "binary_path": "./vrouter"
+ }
+}
\ No newline at end of file
diff --git a/lnxfiles/r3h2/nodes.json b/lnxfiles/r3h2/nodes.json
new file mode 100644
index 0000000..27ea8c5
--- /dev/null
+++ b/lnxfiles/r3h2/nodes.json
@@ -0,0 +1,7 @@
+{
+ "h1": "host",
+ "h2": "host",
+ "r1": "router",
+ "r2": "router",
+ "r3": "router"
+}
\ No newline at end of file
diff --git a/lnxfiles/vhost b/lnxfiles/vhost
new file mode 100755
index 0000000..b240f26
--- /dev/null
+++ b/lnxfiles/vhost
diff --git a/lnxfiles/vrouter b/lnxfiles/vrouter
new file mode 100755
index 0000000..c89f6fe
--- /dev/null
+++ b/lnxfiles/vrouter
diff --git a/pkg/ipstack/ipstack.go b/pkg/ipstack/ipstack.go
index 959e5ff..c2d83ba 100644
--- a/pkg/ipstack/ipstack.go
+++ b/pkg/ipstack/ipstack.go
@@ -12,8 +12,6 @@ import (
 	"net/netip"
 	"sync"
 	"time"
-	// "bytes"
-	// "unicode"
 )
 
 const (
@@ -64,8 +62,8 @@ type Hop struct {
 }
 
 // GLOBAL VARIABLES (data structures) ------------------------------------------
-var myVIP Interface
 var myInterfaces []*Interface
+
 var myNeighbors = make(map[string][]*Neighbor)
 
 var myRIPNeighbors = make(map[string]*Neighbor)
@@ -78,6 +76,8 @@ var routingTable = make(map[netip.Prefix]Hop)
 
 // ************************************** INIT FUNCTIONS **********************************************************
 // reference: https://github.com/brown-csci1680/lecture-examples/blob/main/ip-demo/cmd/udp-ip-recv/main.go
+
+// createUDPListener creates a UDP listener.
 func createUDPListener(UdpAddr netip.AddrPort, conn *net.UDPConn) error {
 	listenString := UdpAddr.String()
 	listenAddr, err := net.ResolveUDPAddr("udp4", listenString)
@@ -93,6 +93,7 @@ func createUDPListener(UdpAddr netip.AddrPort, conn *net.UDPConn) error {
 	return nil
 }
 
+// initialize parse the lnxfile and initializes the data structures and listener routines
 func Initialize(lnxFilePath string) error {
 	// Parse the file
 	lnxConfig, err := lnxconfig.ParseConfig(lnxFilePath)
@@ -100,7 +101,7 @@ func Initialize(lnxFilePath string) error {
 		return errors.WithMessage(err, "Error parsing config file->\t"+lnxFilePath)
 	}
 
-	// 1) add each local if to the routing table, as dictated by its subnet
+	// 1) add each local "if" to the routing table, as dictated by its subnet
 	for _, iface := range lnxConfig.Interfaces {
 		prefix := netip.PrefixFrom(iface.AssignedIP, iface.AssignedPrefix.Bits())
 		i := &Interface{
@@ -111,16 +112,20 @@ func Initialize(lnxFilePath string) error {
 			SocketChannel: make(chan bool),
 			State:         true,
 		}
-		// Added this for printing purposes for REPL FYI, if you have a better way lmk
 
+		// create the UDP listener
 		err := createUDPListener(iface.UDPAddr, &i.RecvSocket)
 		if err != nil {
 			return errors.WithMessage(err, "Error creating UDP socket for interface->\t"+iface.Name)
 		}
 
+		// start the listener routine
 		go InterfaceListenerRoutine(i)
+
+		// add to the list of interfaces
 		myInterfaces = append(myInterfaces, i)
 
+		// add to the routing table
 		routingTable[prefix.Masked()] = Hop{LOCAL_COST, "L", i, prefix.Addr()}
 	}
 
@@ -162,10 +167,10 @@ func Initialize(lnxFilePath string) error {
 		}
 	}
 
-	// add protocol handlers
 	return nil
 }
 
+// defines the go routine that listens on the UDP socket
 func InterfaceListenerRoutine(i *Interface) {
 	// decompose the interface
 	socket := i.RecvSocket
@@ -175,8 +180,9 @@ func InterfaceListenerRoutine(i *Interface) {
 	isUp := true
 	closed := false
 
-	// go routine that hangs on the recv
 	// fmt.Println("MAKING GO ROUTINE TO LISTEN:\t", socket.LocalAddr().String())
+
+	// go routine that hangs on the recv
 	go func() {
 		defer func() {
 			fmt.Println("exiting go routine that listens on ", socket.LocalAddr().String())
@@ -186,14 +192,15 @@ func InterfaceListenerRoutine(i *Interface) {
 			if closed { // stop this go routine if channel is closed
 				return
 			}
+
 			//if !isUp { // don't call the listeners if interface is down
 			//	continue
 			//}
+
 			// TODO: remove these "training wheels"
 			time.Sleep(1 * time.Millisecond)
 			err := RecvIP(i, &isUp)
 			if err != nil {
-				// fmt.Println("Error receiving IP packet", err)
 				continue
 			}
 		}
@@ -201,6 +208,7 @@ func InterfaceListenerRoutine(i *Interface) {
 
 	for {
 		select {
+		// if the channel is closed, exit
 		case sig, ok := <-signal:
 			if !ok {
 				fmt.Println("channel closed, exiting")
@@ -209,6 +217,7 @@ func InterfaceListenerRoutine(i *Interface) {
 			}
 			// fmt.Println("received isUP SIGNAL with value", sig)
 			isUp = sig
+		// if the channel is not closed, continue
 		default:
 			continue
 		}
@@ -217,7 +226,9 @@ func InterfaceListenerRoutine(i *Interface) {
 
 // ************************************** DOWN/UP FUNCTIONS ******************************************************
 
+// sets the interface to be up and sends a triggered update
 func InterfaceUp(iface *Interface) {
+	// set the state to up and send the signal
 	iface.State = true
 	iface.SocketChannel <- true
 
@@ -235,12 +246,13 @@ func InterfaceUpREPL(ifaceName string) {
 		fmt.Println("Error getting interface by name", err)
 		return
 	}
+	// set the state to up and send the signal
 	InterfaceUp(iface)
 }
 
-// we could do either of these but the REPL results in less work done in router and host
-
+// sets the interface to be down and sends a triggered update
 func InterfaceDown(iface *Interface) {
+	// set the state to down and send the signal
 	iface.SocketChannel <- false
 	iface.State = false
 
@@ -258,6 +270,7 @@ func InterfaceDownREPL(ifaceName string) {
 		fmt.Println("Error getting interface by name", err)
 		return
 	}
+	// set the state to down and send the signal
 	InterfaceDown(iface)
 }
 
@@ -272,31 +285,6 @@ func GetInterfaceByName(ifaceName string) (*Interface, error) {
 	return nil, errors.Errorf("No interface with name %s", ifaceName)
 }
 
-func GetNeighborByIP(ipAddr string) (*Neighbor, error) {
-	// iterate through the neighbors and return the one with the same ipAddr
-	for _, neighbors := range myNeighbors {
-		for _, neighbor := range neighbors {
-			if neighbor.VipAddr.String() == ipAddr {
-				return neighbor, nil
-			}
-		}
-	}
-
-	return nil, errors.Errorf("No interface with ip %s", ipAddr)
-}
-
-func GetNeighborsToInterface(ifaceName string) ([]*Neighbor, error) {
-	if neighbors, ok := myNeighbors[ifaceName]; ok {
-		return neighbors, nil
-	}
-
-	return nil, errors.Errorf("No interface with name %s", ifaceName)
-}
-
-func GetMyVIP() Interface {
-	return myVIP
-}
-
 func GetInterfaces() []*Interface {
 	return myInterfaces
 }
@@ -311,22 +299,27 @@ func GetRoutes() map[netip.Prefix]Hop {
 
 // ************************************** PRINT FUNCTIONS **********************************************************
 
+// Sprint functions return a string representation of the myInterfaces data structure
 func SprintInterfaces() string {
 	tmp := ""
 	for _, iface := range myInterfaces {
 		if iface.State {
+			// if the state is up, print UP
 			tmp += fmt.Sprintf("%s\t%s\t%s\n", iface.Name, iface.IpPrefix.String(), "UP")
 		} else {
+			// if the state is down, print DOWN
 			tmp += fmt.Sprintf("%s\t%s\t%s\n", iface.Name, iface.IpPrefix.String(), "DOWN")
 		}
 	}
 	return tmp
 }
 
+// Sprint functions return a string representation of the myNeighbors data structure
 func SprintNeighbors() string {
 	tmp := ""
 	for _, iface := range myInterfaces {
 		if !iface.State {
+			// if the interface is down, skip it
 			continue
 		}
 		for _, n := range myNeighbors[iface.Name] {
@@ -1017,7 +1010,7 @@ func LongestPrefix(src netip.Addr) (Hop, error) {
 //			for _, ripNeighbor := range myRIPNeighbors {
 //				if neighbor.VipAddr.String() == ripNeighbor.String() {
 //					// send RIP message
-//					err := SendRIPMessage(myVIP, neighbor, message)
+					// err := SendRIPMessage(myVIP, neighbor, message)
 //					if err != nil {
 //						continue
 //					}
@@ -1107,7 +1100,7 @@ func LongestPrefix(src netip.Addr) (Hop, error) {
 //			// send RIP message
 //			for _, Interfaces := range myInterfaces {
 //				if Interfaces.Name == neighbor.Name {
-//					err := SendRIPMessage(myVIP, neighbor, message)
+					// err := SendRIPMessage(myVIP, neighbor, message)
 //					if err != nil {
 //						continue
 //					}
diff --git a/vhost b/vhost
index ac23975..1fdc5aa 100755
--- a/vhost
+++ b/vhost
diff --git a/vrouter b/vrouter
index 5455b09..e1339b8 100755
--- a/vrouter
+++ b/vrouter