implement basic triggered updates, but there is still a small bug with rerouting after a router goes down I need to fix. also, fixed the print functions and returned them to sprint so I can test.

5 files changed, 101 insertions, 67 deletions

diff --git a/cmd/vhost/main.go b/cmd/vhost/main.go
index 468409d..dbf899a 100644
--- a/cmd/vhost/main.go
+++ b/cmd/vhost/main.go
@@ -30,13 +30,13 @@ func main() {
 		switch line {
 		case "li":
 			fmt.Println("Name\tAddr/Prefix\tState")
-			ipstack.SprintInterfaces()
+			fmt.Println(ipstack.SprintInterfaces())
 		case "ln":
 			fmt.Println("Iface\tVIP\tUDPAddr")
-			ipstack.SprintNeighbors()
+			fmt.Println(ipstack.SprintNeighbors())
 		case "lr":
 			fmt.Println("T\tPrefix\tNext Hop\tCost")
-			ipstack.SprintRoutingTable()
+			fmt.Println(ipstack.SprintRoutingTable())
 		case "q":
 			ipstack.CleanUp()
 			os.Exit(0)
diff --git a/cmd/vrouter/main.go b/cmd/vrouter/main.go
index 7998e5d..cde49a8 100644
--- a/cmd/vrouter/main.go
+++ b/cmd/vrouter/main.go
@@ -44,13 +44,13 @@ func main() {
 		switch line {
 		case "li":
 			fmt.Println("Name\tAddr/Prefix\tState")
-			ipstack.SprintInterfaces()
+			fmt.Println(ipstack.SprintInterfaces())
 		case "ln":
 			fmt.Println("Iface\tVIP\tUDPAddr")
-			ipstack.SprintNeighbors()
+			fmt.Println(ipstack.SprintNeighbors())
 		case "lr":
 			fmt.Println("T\tPrefix\tNext Hop\tCost")
-			ipstack.SprintRoutingTable()
+			fmt.Println(ipstack.SprintRoutingTable())
 		case "q":
 			ipstack.CleanUp()
 			os.Exit(0)
diff --git a/pkg/ipstack/ipstack.go b/pkg/ipstack/ipstack.go
index 2116403..e949824 100644
--- a/pkg/ipstack/ipstack.go
+++ b/pkg/ipstack/ipstack.go
@@ -176,7 +176,7 @@ func InterfaceListenerRoutine(i *Interface) {
 	closed := false
 
 	// go routine that hangs on the recv
-	fmt.Println("MAKING GO ROUTINE TO LISTEN:\t", socket.LocalAddr().String())
+	// fmt.Println("MAKING GO ROUTINE TO LISTEN:\t", socket.LocalAddr().String())
 	go func() {
 		defer func() {
 			fmt.Println("exiting go routine that listens on ", socket.LocalAddr().String())
@@ -193,8 +193,8 @@ func InterfaceListenerRoutine(i *Interface) {
 			time.Sleep(1 * time.Millisecond)
 			err := RecvIP(i, &isUp)
 			if err != nil {
-				fmt.Println("Error receiving IP packet", err)
-				return
+				// fmt.Println("Error receiving IP packet", err)
+				continue
 			}
 		}
 	}()
@@ -207,7 +207,7 @@ func InterfaceListenerRoutine(i *Interface) {
 				closed = true
 				return
 			}
-			fmt.Println("received isUP SIGNAL with value", sig)
+			// fmt.Println("received isUP SIGNAL with value", sig)
 			isUp = sig
 		default:
 			continue
@@ -220,6 +220,13 @@ func InterfaceListenerRoutine(i *Interface) {
 func InterfaceUp(iface *Interface) {
 	iface.State = true
 	iface.SocketChannel <- true
+
+	// if were a router, send triggered updates on up
+	if _, ok := protocolHandlers[RIP_PROTOCOL]; ok {
+		ripEntries := make([]RIPEntry, 0)
+		ripEntries = append(ripEntries, RIPEntry{iface.IpPrefix.Masked(), LOCAL_COST})
+		sendTriggeredUpdates(ripEntries)
+	}
 }
 
 func InterfaceUpREPL(ifaceName string) {
@@ -236,6 +243,13 @@ func InterfaceUpREPL(ifaceName string) {
 func InterfaceDown(iface *Interface) {
 	iface.SocketChannel <- false
 	iface.State = false
+
+	// if were a router, send triggered updates on down
+	if _, ok := protocolHandlers[RIP_PROTOCOL]; ok {
+		ripEntries := make([]RIPEntry, 0)
+		ripEntries = append(ripEntries, RIPEntry{iface.IpPrefix.Masked(), INFINITY})
+		sendTriggeredUpdates(ripEntries)
+	}
 }
 
 func InterfaceDownREPL(ifaceName string) {
@@ -297,66 +311,45 @@ func GetRoutes() map[netip.Prefix]Hop {
 
 // ************************************** PRINT FUNCTIONS **********************************************************
 
-func SprintInterfaces() {
+func SprintInterfaces() string {
+	tmp := ""
 	for _, iface := range myInterfaces {
 		if iface.State {
-			fmt.Printf("%s\t%s\t%s\n", iface.Name, iface.IpPrefix.String(), "UP")
+			tmp += fmt.Sprintf("%s\t%s\t%s\n", iface.Name, iface.IpPrefix.String(), "UP")
 		} else {
-			fmt.Printf("%s\t%s\t%s\n", iface.Name, iface.IpPrefix.String(), "DOWN")
+			tmp += fmt.Sprintf("%s\t%s\t%s\n", iface.Name, iface.IpPrefix.String(), "DOWN")
 		}
 	}
+	return tmp
 }
 
-func SprintNeighbors() {
-	for ifaceName, neighbor := range myNeighbors {
-		for _, n := range neighbor {
-			fmt.Printf("%s\t%s\t%s\n", ifaceName, n.VipAddr.String(), n.UdpAddr.String())
+func SprintNeighbors() string {
+	tmp := ""
+	for _, iface := range myInterfaces {
+		if !iface.State {
+			continue
+		}
+		for _, n := range myNeighbors[iface.Name] {
+			tmp += fmt.Sprintf("%s\t%s\t%s\n", iface.Name, n.VipAddr.String(), n.UdpAddr.String())
 		}
 	}
+	return tmp
 }
 
-func SprintRoutingTable() {
+func SprintRoutingTable() string {
+	tmp := ""
 	for prefix, hop := range routingTable {
 		if hop.Type == "L" {
-			fmt.Printf("%s\t%s\tLOCAL:%s\t%d\n", hop.Type, prefix.String(), hop.Interface.Name, 0)
+			tmp += fmt.Sprintf("%s\t%s\tLOCAL:%s\t%d\n", hop.Type, prefix.String(), hop.Interface.Name, 0)
 		} else if hop.Type == "S" {
-			fmt.Printf("%s\t%s\t%s\t%s\n", hop.Type, prefix.String(), hop.VIP.String(), "-")
+			tmp += fmt.Sprintf("%s\t%s\t%s\t%s\n", hop.Type, prefix.String(), hop.VIP.String(), "-")
 		} else {
-			fmt.Printf("%s\t%s\t%s\t%d\n", hop.Type, prefix.String(), hop.VIP.String(), hop.Cost)
+			tmp += fmt.Sprintf("%s\t%s\t%s\t%d\n", hop.Type, prefix.String(), hop.VIP.String(), hop.Cost)
 		}
 	}
+	return tmp
 }
 
-func DebugNeighbors() {
-	for ifaceName, neighbor := range myNeighbors {
-		for _, n := range neighbor {
-			fmt.Printf("%s\t%s\t%s\n", ifaceName, n.UdpAddr.String(), n.VipAddr.String())
-		}
-	}
-}
-
-//// TODO @ MICHAEL:
-//func RemoveNeighbor(neighbor Neighbor) {
-//	// TODO: remove from routing table
-//	myRoutes := GetRoutes()
-//	for prefix, hop := range myRoutes {
-//		if hop.VipAsStr == neighbor.VipAddr.String() {
-//			delete(myRoutes, prefix)
-//		}
-//	}
-//
-//	// TODO: remove from myNeighbors
-//	myNeighbors[neighbor.VipAddr.String()] = nil
-//
-//	// TODO: close the UDP socket
-//	err := neighbor.SendSocket.Close()
-//	if err != nil {
-//		fmt.Println("Error closing UDP socket", err)
-//	}
-//
-//}
-// untested function above
-
 // ************************************** BASIC FUNCTIONS **********************************************************
 
 func CleanUp() {
@@ -384,6 +377,11 @@ func CleanUp() {
 
 // TODO: have it take TTL so we can decrement it when forwarding
 func SendIP(src *netip.Addr, dest *Neighbor, protocolNum int, message []byte, destIP string, hdr *ipv4header.IPv4Header) (int, error) {
+	iface, err := GetInterfaceByName(dest.Name)
+	if !iface.State {
+		return -1, errors.New("error: interface is down")
+	}
+
 	if hdr == nil {
 		hdr = &ipv4header.IPv4Header{
 			Version:  4,
@@ -447,7 +445,6 @@ func SendIP(src *netip.Addr, dest *Neighbor, protocolNum int, message []byte, de
 
 	// bytesWritten, err := tmpConn.Write(bytesToSend)
 	// TODO: make this faster by removing call
-	iface, err := GetInterfaceByName(dest.Name)
 	bytesWritten, err := iface.RecvSocket.WriteToUDP(bytesToSend, sendAddr)
 	if err != nil {
 		fmt.Println("Error writing to UDP socket")
@@ -467,7 +464,6 @@ func RecvIP(iface *Interface, isOpen *bool) error {
 	// Read on the UDP port
 	// Too much printing so I commented it out
 	// fmt.Println("wating to read from UDP socket")
-	// TODO: this is erroring here!!
 	_, _, err := conn.ReadFromUDP(buffer)
 	if err != nil {
 		return err
@@ -522,7 +518,7 @@ func RecvIP(iface *Interface, isOpen *bool) error {
 	// at this point, the packet is valid. next steps consider the forwarding of the packet
 	// 2) check if the message is for me, if so, sendUP (aka call the correct handler)
 	if hdr.Protocol != RIP_PROTOCOL {
-		// fmt.Println("I see a non-rip packet")
+		fmt.Println("I see a non-rip packet")
 	}
 	if hdr.Dst == prefix.Addr() {
 		// see if there is a handler for this protocol
@@ -646,7 +642,7 @@ func periodicUpdateRoutine() {
 				addr := iface.IpPrefix.Addr()
 				_, err := SendIP(&addr, n, RIP_PROTOCOL, message, n.VipAddr.String(), nil)
 				if err != nil {
-					fmt.Printf("Error sending RIP message to %s\n", n.VipAddr.String())
+					// fmt.Printf("Error sending RIP message to %s\n", n.VipAddr.String())
 					continue
 				}
 			}
@@ -661,6 +657,25 @@ var mu sync.Mutex
 var timeoutTable = make(map[netip.Prefix]int)
 var MAX_TIMEOUT = 12
 
+func sendTriggeredUpdates(newEntries []RIPEntry) {
+	for _, iface := range myInterfaces {
+		for _, n := range myNeighbors[iface.Name] {
+			_, in := myRIPNeighbors[n.VipAddr.String()]
+			if !in {
+				continue
+			}
+
+			message := makeRipMessage(2, newEntries)
+			addr := iface.IpPrefix.Addr()
+			_, err := SendIP(&addr, n, RIP_PROTOCOL, message, n.VipAddr.String(), nil)
+			if err != nil {
+				// fmt.Printf("Error sending RIP triggered update to %s\n", n.VipAddr.String())
+				continue
+			}
+		}
+	}
+}
+
 func manageTimeoutsRoutine() {
 	for {
 		time.Sleep(time.Second)
@@ -690,9 +705,15 @@ func manageTimeoutsRoutine() {
 			if timeoutTable[prefix] == MAX_TIMEOUT {
 				delete(routingTable, prefix)
 				delete(timeoutTable, prefix)
-				// TODO: send triggered update
+				// send triggered update on timeout
+				go func(p netip.Prefix) {
+					newEntries := make([]RIPEntry, 0)
+					newEntries = append(newEntries, RIPEntry{p, INFINITY})
+					sendTriggeredUpdates(newEntries)
+				}(prefix)
 			}
 		}
+		// fmt.Println("timeout table: ", timeoutTable)
 		mu.Unlock()
 
 		// fmt.Println("Timeout table: ", timeoutTable)
@@ -816,27 +837,40 @@ func handleRIP(src *Interface, dest *Neighbor, message []byte, hdr *ipv4header.I
 			// potentially, may have to apply mask first
 			// fmt.Println(address)
 
-			prefix := entry.prefix
+			destination := entry.prefix.Masked()
 			// fmt.Println(prefix.String())
 
 			// check if the entry is already in the routing table and update if need be
-			if node, ok := routingTable[prefix.Masked()]; ok {
-				if entry.cost < node.Cost {
-					routingTable[prefix.Masked()] = Hop{entry.cost + 1, "R", src, hdr.Src}
+			if hop, ok := routingTable[destination]; ok {
+				// if the hop is the same as the incoming neighbor,
+				// then we can increase the cost by that new value
+				if hop.VIP == hdr.Src &&
+					entry.cost > hop.Cost {
+					routingTable[destination] = Hop{entry.cost + 1, "R", src, hdr.Src}
 				}
-				if node.Type == "R" {
+
+				// if there is a shorter route for this destination on a different (or same) neighbor
+				// then update to use that one
+				if entry.cost < hop.Cost {
+					routingTable[destination] = Hop{entry.cost + 1, "R", src, hdr.Src}
+				}
+
+				// upon an update from this prefix, reset its timeout
+				if hop.Type == "R" {
 					mu.Lock()
-					timeoutTable[prefix.Masked()] = 0
+					timeoutTable[destination] = 0
 					mu.Unlock()
 				}
 				continue
 			}
 
-			if entry.cost == 17 {
-				routingTable[prefix.Masked()] = Hop{0, "R", src, hdr.Src}
-			} else {
-				routingTable[prefix.Masked()] = Hop{entry.cost + 1, "R", src, hdr.Src}
-			}
+			// fmt.Println("Adding new route to routing table: ", destination.String(), entry.cost)
+			// @ david, where did the 17 come from
+			//if entry.cost == 17 {
+			//	routingTable[destination] = Hop{0, "R", src, hdr.Src}
+			//} else {
+			routingTable[destination] = Hop{entry.cost + 1, "R", src, hdr.Src}
+			// }
 		}
 	}
 
diff --git a/vhost b/vhost
index aa6346f..c61fd2b 100755
--- a/vhost
+++ b/vhost
diff --git a/vrouter b/vrouter
index 0dc05d1..88ed19c 100755
--- a/vrouter
+++ b/vrouter