good progress, fixing almost all of the red. in the process of ensuring the data structures are initialized correctly.

1 files changed, 121 insertions, 72 deletions

diff --git a/pkg/ipstack/ipstack.go b/pkg/ipstack/ipstack.go
index 770fd17..abaa09f 100644
--- a/pkg/ipstack/ipstack.go
+++ b/pkg/ipstack/ipstack.go
@@ -2,102 +2,147 @@ package ipstack
 
 import (
 	"fmt"
-	ipv4header "github.com/brown-csci1680/iptcp-headers"
-	"github.com/google/netstack/tcpip/header"
 	"github.com/pkg/errors"
-	"../../pkg/lnxconfig"
-	"log"
+	"iptcp/pkg/lnxconfig"
 	"net"
 	"net/netip"
-	"os"
 )
 
 const (
-	MAX_IP_PACKET_SIZE = 1400
+	MAX_IP_PACKET_SIZE        = 1400
+	LOCAL_COST         uint32 = 4294967295 // 2^32 - 1
+	STATIC_COST        uint32 = 1
 )
 
+// STRUCTS ---------------------------------------------------------------------
 type Interface struct {
-	Name           string
-	AssignedIP     netip.Addr
-	AssignedPrefix netip.Prefix
+	Name      string
+	IpAddress netip.Addr
+	IpPrefix  netip.Prefix
 
-	UDPAddr netip.AddrPort
-	State bool
-	neighbors map[netip.AddrPort]netip.AddrPort
+	RecvSocket    net.Conn
+	SocketChannel chan<- bool
+	State         bool
 }
 
-// type Host struct {
-// 	Interface Interface
-// 	Neighbors []Neighbor
-// }
-
-// type Router struct {
-// 	Interfaces []Interface
-// 	Neighbors []Neighbor
-// 	RIPNeighbors []Neighbor
-// }
+type Neighbor struct {
+	VipAddr netip.Addr
+	UdpAddr netip.AddrPort
 
-
-type Neighbor struct{
-	DestAddr netip.Addr
-	UDPAddr  netip.AddrPort
-
-	InterfaceName string
+	SendSocket    net.Conn
+	SocketChannel chan<- bool
 }
 
 type RIPMessage struct {
-	command uint8_t;
-	numEntries uint8_t;
-	entries []RIPEntry;
+	command    uint8
+	numEntries uint8
+	entries    []RIPEntry
 }
 
 type RIPEntry struct {
-	addr netip.Addr;
-	cost uint16_t;
-	mask netip.Prefix;
+	addr netip.Addr
+	cost uint32
+	mask netip.Prefix
 }
 
-myInterfaces := make([]Interface);
-myNeighbors :=  make(map[string]Neighbor)
-myRIPNeighbors := make(map[string]Neighbor)
-protocolHandlers := make(map[uint16]HandlerFunc)
-// routingTable := make(map[Address]Routing)
+type Hop struct {
+	Cost     uint32
+	VipAsStr string
+}
 
-func Initialize(config IpConfig) (error) {
-	if len(os.Args) != 2 {
-		fmt.Printf("Usage:  %s <configFile>\n", os.Args[0])
-		os.Exit(1)
+// GLOBAL VARIABLES (data structures) ------------------------------------------
+var myInterfaces []Interface
+var myNeighbors = make(map[string]Neighbor)
+
+// var myRIPNeighbors = make(map[string]Neighbor)
+type HandlerFunc func(int, string, *[]byte) error
+
+var protocolHandlers = make(map[uint16]HandlerFunc)
+
+// var routingTable = routingtable.New()
+var routingTable = make(map[netip.Prefix]Hop)
+
+// reference: https://github.com/brown-csci1680/lecture-examples/blob/main/ip-demo/cmd/udp-ip-recv/main.go
+func createUDPConn(UdpAddr netip.AddrPort, conn *net.Conn) error {
+	listenString := UdpAddr.String()
+	listenAddr, err := net.ResolveUDPAddr("udp4", listenString)
+	if err != nil {
+		return errors.WithMessage(err, "Error resolving address->\t"+listenString)
 	}
-	fileName := os.Args[1]
+	tmpConn, err := net.ListenUDP("udp4", listenAddr)
+	if err != nil {
+		return errors.WithMessage(err, "Could not bind to UDP port->\t"+listenString)
+	}
+	*conn = tmpConn
+
+	return nil
+}
+
+func Initialize(lnxFilePath string) error {
+	//if len(os.Args) != 2 {
+	//	fmt.Printf("Usage:  %s <configFile>\n", os.Args[0])
+	//	os.Exit(1)
+	//}
+	//lnxFilePath := os.Args[1]
 
 	// Parse the file
-	lnxConfig, err := lnxconfig.ParseConfig(fileName)
+	lnxConfig, err := lnxconfig.ParseConfig(lnxFilePath)
 	if err != nil {
-		panic(err)
+		return errors.WithMessage(err, "Error parsing config file->\t"+lnxFilePath)
 	}
 
-	// populate routing table??? 
+	// 1) initialize the interfaces on this node here and into the routing table
 	for _, iface := range lnxConfig.Interfaces {
-		myInterfaces = append(myInterfaces, Interface{iface.Name, iface.AssignedIP, iface.AssignedPrefix, iface.UDPAddr, 0})
+		i := &Interface{
+			Name:          iface.Name,
+			IpAddress:     iface.AssignedIP,
+			IpPrefix:      iface.AssignedPrefix,
+			RecvSocket:    nil,
+			SocketChannel: nil,
+			State:         false,
+		}
+		err := createUDPConn(iface.UDPAddr, &i.RecvSocket)
+		if err != nil {
+			return errors.WithMessage(err, "Error creating UDP socket for interface->\t"+iface.Name)
+		}
+		myInterfaces = append(myInterfaces, *i)
+
+		// add to routing table
+		ifacePrefix := netip.PrefixFrom(iface.AssignedIP, iface.AssignedPrefix.Bits())
+		routingTable[ifacePrefix] = Hop{STATIC_COST, iface.Name}
 	}
 
+	// 2) initialize the neighbors connected to the node
 	for _, neighbor := range lnxConfig.Neighbors {
-		myNeighbors[neighbor.DestAddr.String()] = Neighbor{neighbor.DestAddr, neighbor.UDPAddr, neighbor.InterfaceName}
-	}
+		n := &Neighbor{
+			VipAddr:    neighbor.DestAddr,
+			UdpAddr:    neighbor.UDPAddr,
+			SendSocket: nil,
+		}
+		err := createUDPConn(neighbor.UDPAddr, &n.SendSocket)
+		if err != nil {
+			return errors.WithMessage(err, "Error creating UDP socket for neighbor->\t"+neighbor.DestAddr.String())
+		}
+		// TODO: make a hash map
+		myNeighbors[neighbor.InterfaceName] = *n
 
-	// add RIP neighbors
-	for _, neighbor := range lnxConfig.RipNeighbors {
-		myRIPNeighbors[neighbor.DestAddr.String()] = Neighbor{neighbor.DestAddr, neighbor.UDPAddr, neighbor.InterfaceName}
+		// add to routing table
+		neighborPrefix := netip.PrefixFrom(neighbor.DestAddr, 24)
+		routingTable[neighborPrefix] = Hop{LOCAL_COST, neighbor.InterfaceName}
 	}
+
+	return nil
 }
 
+/*
+
 func ListerToInterfaces() {
 	for _, iface := range myInterfaces {
 		go RecvIp(iface)
 	}
 }
 
-func RecvIp(iface Interface) (error) {
+func RecvIp(iface Interface) error {
 	for {
 		buffer := make([]byte, MAX_IP_PACKET_SIZE)
 		_, sourceAddr, err := iface.udp.ReadFrom(buffer)
@@ -125,7 +170,7 @@ func RecvIp(iface Interface) (error) {
 			checksumState = "FAIL"
 			continue
 		}
-		
+
 		// check ttl
 		ttl := data[8]
 		if ttl == 0 {
@@ -133,7 +178,6 @@ func RecvIp(iface Interface) (error) {
 			continue
 		}
 
-
 		destAddr := netip.AddrFrom(data[16:20])
 		protocolNum := data[9]
 
@@ -174,7 +218,7 @@ func ValidateChecksum(b []byte, fromHeader uint16) uint16 {
 	return checksum
 }
 
-func SendIp(dst netip.Addr, port uint16, protocolNum uint16, data []byte, iface Interface) (error) {
+func SendIp(dst netip.Addr, port uint16, protocolNum uint16, data []byte, iface Interface) error {
 	bindLocalAddr, err := net.ResolveUDPAddr("udp4", iface.UDPAddr.String())
 	if err != nil {
 		log.Panicln("Error resolving address:  ", err)
@@ -248,15 +292,10 @@ func ComputeChecksum(b []byte) uint16 {
 	return checksumInv
 }
 
-func ForwardIP(data []byte) (error) {
-}
-
-type HandlerFunc = func help(*Packet, []interface{}) (error) {
-
-	// do smth with packet
+func ForwardIP(data []byte) error {
 }
 
-func AddRecvHandler(protocolNum uint8, callbackFunc HandlerFunc) (error) {
+func AddRecvHandler(protocolNum uint8, callbackFunc HandlerFunc) error {
 	if protocolHandlers[protocolNum] != nil {
 		fmt.Printf("Warning: Handler for protocol %d already exists", protocolNum)
 	}
@@ -264,7 +303,7 @@ func AddRecvHandler(protocolNum uint8, callbackFunc HandlerFunc) (error) {
 	return nil
 }
 
-func RemoveRecvHandler(protocolNum uint8) (error) {
+func RemoveRecvHandler(protocolNum uint8) error {
 	// consider error
 	if protocolHandlers[protocolNum] == nil {
 		return errors.Errorf("No handler for protocol %d", protocolNum)
@@ -281,18 +320,28 @@ func RemoveRecvHandler(protocolNum uint8) (error) {
 // 	newRIPMessage.entries = make([]RIPEntry, newRIPMessage.numEntries)
 // }
 
-func PrintNeighbors() {
-	for _, iface := range myNeighbors {
-		fmt.Printf("%s\n", iface.addr.String())
-	}
+func GetNeighbors() []netip.Addr {
+	return myNeighbors
 }
+*/
 
 func PrintInterfaces() {
 	for _, iface := range myInterfaces {
-		fmt.Printf("%s\n", iface.addr.String())
+		fmt.Printf("%s\t%s\t%t\n", iface.Name, iface.IpPrefix.String(), iface.State)
 	}
 }
-func GetNeighbors() ([]netip.Addr) {
-	return myNeighbors
+
+func PrintNeighbors() {
+	for ifaceName, neighbor := range myNeighbors {
+		fmt.Printf("%s\t%s\t%s\n", ifaceName, neighbor.IpAddress.String(), neighbor.UdpAddr.String())
+	}
 }
 
+func SprintRoutingTable() string {
+	message := ""
+	for prefix, hop := range routingTable {
+		message += fmt.Sprintf("%s\t%s\t%d\n", prefix.String(), hop.VipAsStr, hop.Cost)
+	}
+
+	return message
+}