implement recvip and sendip, with tests to know it's working

1 files changed, 148 insertions, 0 deletions

diff --git a/pkg/ipstack/ipstack_test.go b/pkg/ipstack/ipstack_test.go
index ae71bba..c6103ee 100644
--- a/pkg/ipstack/ipstack_test.go
+++ b/pkg/ipstack/ipstack_test.go
@@ -2,6 +2,9 @@ package ipstack
 
 import (
 	"fmt"
+	ipv4header "github.com/brown-csci1680/iptcp-headers"
+	"net"
+	"net/netip"
 	"testing"
 	"time"
 )
@@ -103,3 +106,148 @@ func TestInterfaceUpThenDownTwice(t *testing.T) {
 	fmt.Println("TestInterfaceUpThenDownTwice successful")
 	t.Cleanup(func() { CleanUp() })
 }
+
+func TestSendIPToNeighbor(t *testing.T) {
+	lnxFilePath := "../../doc-example/r2.lnx"
+	err := Initialize(lnxFilePath)
+	if err != nil {
+		t.Error(err)
+	}
+
+	// get the first neighbor of this interface
+	iface, err := GetInterfaceByName("if0")
+	if err != nil {
+		t.Error(err)
+	}
+	neighbors, err := GetNeighborsToInterface("if0")
+	if err != nil {
+		t.Error(err)
+	}
+
+	// setup a neighbor listener socket
+	testNeighbor := neighbors[0]
+	// close the socket so we can listen on it
+	err = testNeighbor.SendSocket.Close()
+	if err != nil {
+		t.Error(err)
+	}
+
+	fmt.Printf("Interfaces:\n%s\n", SprintInterfaces())
+	fmt.Printf("Neighbors:\n%s\n", SprintNeighbors())
+
+	listenString := testNeighbor.UdpAddr.String()
+	fmt.Println("listening on " + listenString)
+	listenAddr, err := net.ResolveUDPAddr("udp4", listenString)
+	if err != nil {
+		t.Error(err)
+	}
+	recvSocket, err := net.ListenUDP("udp4", listenAddr)
+	if err != nil {
+		t.Error(err)
+	}
+	testNeighbor.SendSocket = *recvSocket
+
+	sent := false
+	go func() {
+		buffer := make([]byte, MAX_IP_PACKET_SIZE)
+		fmt.Println("wating to read from UDP socket")
+		_, sourceAddr, err := recvSocket.ReadFromUDP(buffer)
+		if err != nil {
+			t.Error(err)
+		}
+		fmt.Println("read from UDP socket")
+		hdr, err := ipv4header.ParseHeader(buffer)
+		if err != nil {
+			t.Error(err)
+		}
+		headerSize := hdr.Len
+		headerBytes := buffer[:headerSize]
+		checksumFromHeader := uint16(hdr.Checksum)
+		computedChecksum := ValidateChecksum(headerBytes, checksumFromHeader)
+
+		var checksumState string
+		if computedChecksum == checksumFromHeader {
+			checksumState = "OK"
+		} else {
+			checksumState = "FAIL"
+		}
+		message := buffer[headerSize:]
+		fmt.Printf("Received IP packet from %s\nHeader:  %v\nChecksum:  %s\nMessage:  %s\n",
+			sourceAddr.String(), hdr, checksumState, string(message))
+		if err != nil {
+			t.Error(err)
+		}
+
+		sent = true
+	}()
+
+	time.Sleep(10 * time.Millisecond)
+
+	// send a message to the neighbor
+	fmt.Printf("sending message to neighbor\t%t\n", sent)
+	err = SendIP(*iface, *testNeighbor, 0, []byte("hello"))
+	if err != nil {
+		t.Error(err)
+	}
+
+	fmt.Printf("SENT message to neighbor\t%t\n", sent)
+	// give a little time for the message to be sent
+	time.Sleep(1000 * time.Millisecond)
+	if !sent {
+		t.Error("Message not sent")
+		t.Fail()
+	}
+
+	fmt.Println("TestSendIPToNeighbor successful")
+	t.Cleanup(func() { CleanUp() })
+}
+
+func TestRecvIP(t *testing.T) {
+	lnxFilePath := "../../doc-example/r2.lnx"
+	err := Initialize(lnxFilePath)
+	if err != nil {
+		t.Error(err)
+	}
+
+	// get the first neighbor of this interface to RecvIP from
+	iface, err := GetInterfaceByName("if0")
+	if err != nil {
+		t.Error(err)
+	}
+	InterfaceUp(iface)
+
+	// setup a random socket to send an ip packet from
+	listenAddr, err := net.ResolveUDPAddr("udp4", "127.0.0.1:6969")
+	sendSocket, err := net.ListenUDP("udp4", listenAddr)
+
+	// send a message to the neighbor
+	ifaceAsNeighbor := Neighbor{
+		VipAddr:       iface.IpPrefix.Addr(),
+		UdpAddr:       iface.UdpAddr,
+		SendSocket:    iface.RecvSocket,
+		SocketChannel: iface.SocketChannel,
+	}
+	fakeIface := Interface{
+		Name:          "if69",
+		IpPrefix:      netip.MustParsePrefix("10.69.0.1/24"),
+		UdpAddr:       netip.MustParseAddrPort("127.0.0.1:6969"),
+		RecvSocket:    net.UDPConn{},
+		SocketChannel: nil,
+		State:         true,
+	}
+	err = SendIP(fakeIface, ifaceAsNeighbor, 0, []byte("hello"))
+	if err != nil {
+		return
+	}
+
+	time.Sleep(10 * time.Millisecond)
+
+	// TODO: potenially make this a channel, so it actually checks values.
+	// For now, you must read the message from the console.
+
+	err = sendSocket.Close()
+	if err != nil {
+		t.Error(err)
+	}
+	t.Cleanup(func() { CleanUp() })
+}