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#2139 - Implemented routing

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This commit is contained in:
Chris McCarthy
2023-12-22 10:31:11 +00:00
parent ffeb04d6ed
commit ade5f133d0
6 changed files with 381 additions and 42 deletions
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148
src/primaite/simulator/network/hardware/nodes/router.py
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@@ -324,11 +324,10 @@ class RouteEntry(SimComponent):
"""
Represents a single entry in a routing table.
Attributes:
address (IPv4Address): The destination IP address or network address.
subnet_mask (IPv4Address): The subnet mask for the network.
next_hop_ip_address (IPv4Address): The next hop IP address to which packets should be forwarded.
metric (int): The cost metric for this route. Default is 0.0.
:ivar address: The destination IP address or network address.
:ivar subnet_mask: The subnet mask for the network.
:ivar next_hop_ip_address: The next hop IP address to which packets should be forwarded.
:ivar metric: The cost metric for this route. Default is 0.0.
Example:
>>> entry = RouteEntry(
@@ -348,12 +347,6 @@ class RouteEntry(SimComponent):
metric: float = 0.0
"The cost metric for this route. Default is 0.0."
def __init__(self, **kwargs):
for key in {"address", "subnet_mask", "next_hop_ip_address"}:
if not isinstance(kwargs[key], IPv4Address):
kwargs[key] = IPv4Address(kwargs[key])
super().__init__(**kwargs)
def set_original_state(self):
"""Sets the original state."""
vals_to_include = {"address", "subnet_mask", "next_hop_ip_address", "metric"}
@@ -388,6 +381,7 @@ class RouteTable(SimComponent):
"""
routes: List[RouteEntry] = []
default_route: Optional[RouteEntry] = None
sys_log: SysLog
def set_original_state(self):
@@ -433,12 +427,35 @@ class RouteTable(SimComponent):
)
self.routes.append(route)
def set_default_route_next_hop_ip_address(self, ip_address: IPv4Address):
"""
Sets the next-hop IP address for the default route in a routing table.
This method checks if a default route (0.0.0.0/0) exists in the routing table. If it does not exist,
the method creates a new default route with the specified next-hop IP address. If a default route already
exists, it updates the next-hop IP address of the existing default route. After setting the next-hop
IP address, the method logs this action.
:param ip_address: The next-hop IP address to be set for the default route.
"""
if not self.default_route:
self.default_route = RouteEntry(
ip_address=IPv4Address("0.0.0.0"),
subnet_mask=IPv4Address("0.0.0.0"),
next_hop_ip_address=ip_address,
)
else:
self.default_route.next_hop_ip_address = ip_address
self.sys_log.info(f"Default configured to use {ip_address} as the next-hop")
def find_best_route(self, destination_ip: Union[str, IPv4Address]) -> Optional[RouteEntry]:
"""
Find the best route for a given destination IP.
This method uses the Longest Prefix Match algorithm and considers metrics to find the best route.
If no dedicated route exists but a default route does, then the default route is returned as a last resort.
:param destination_ip: The destination IP to find the route for.
:return: The best matching RouteEntry, or None if no route matches.
"""
@@ -458,6 +475,9 @@ class RouteTable(SimComponent):
longest_prefix = prefix_len
lowest_metric = route.metric
if not best_route and self.default_route:
best_route = self.default_route
return best_route
def show(self, markdown: bool = False):
@@ -489,12 +509,26 @@ class RouterARPCache(ARPCache):
super().__init__(sys_log)
self.router: Router = router
def process_arp_packet(self, from_nic: NIC, frame: Frame):
def process_arp_packet(
self, from_nic: NIC, frame: Frame, route_table: RouteTable, is_reattempt: bool = False
) -> None:
"""
Overridden method to process a received ARP packet in a router-specific way.
Processes a received ARP (Address Resolution Protocol) packet in a router-specific way.
This method is responsible for handling both ARP requests and responses. It processes ARP packets received on a
Network Interface Card (NIC) and performs actions based on whether the packet is a request or a reply. This
includes updating the ARP cache, forwarding ARP replies, sending ARP requests for unknown destinations, and
handling packet TTL (Time To Live).
The method first checks if the ARP packet is a request or a reply. For ARP replies, it updates the ARP cache
and forwards the reply if necessary. For ARP requests, it checks if the target IP matches one of the router's
NICs and sends an ARP reply if so. If the destination is not directly connected, it consults the routing table
to find the best route and reattempts ARP request processing if needed.
:param from_nic: The NIC that received the ARP packet.
:param frame: The original ARP frame.
:param frame: The frame containing the ARP packet.
:param route_table: The routing table of the router.
:param is_reattempt: Flag to indicate if this is a reattempt of processing the ARP packet, defaults to False.
"""
arp_packet = frame.arp
@@ -522,7 +556,11 @@ class RouterARPCache(ARPCache):
)
arp_packet.sender_mac_addr = nic.mac_address
frame.decrement_ttl()
if frame.ip and frame.ip.ttl < 1:
self.sys_log.info("Frame discarded as TTL limit reached")
return
nic.send_frame(frame)
return
# ARP Request
self.sys_log.info(
@@ -533,16 +571,32 @@ class RouterARPCache(ARPCache):
self.add_arp_cache_entry(
ip_address=arp_packet.sender_ip_address, mac_address=arp_packet.sender_mac_addr, nic=from_nic
)
arp_packet = arp_packet.generate_reply(from_nic.mac_address)
self.send_arp_reply(arp_packet, from_nic)
# If the target IP matches one of the router's NICs
for nic in self.nics.values():
if nic.enabled and nic.ip_address == arp_packet.target_ip_address:
if arp_packet.target_ip_address in nic.ip_network:
# if nic.enabled and nic.ip_address == arp_packet.target_ip_address:
arp_reply = arp_packet.generate_reply(from_nic.mac_address)
self.send_arp_reply(arp_reply, from_nic)
return
# Check Route Table
route = route_table.find_best_route(arp_packet.target_ip_address)
if route:
nic = self.get_arp_cache_nic(route.next_hop_ip_address)
if not nic:
if not is_reattempt:
self.send_arp_request(route.next_hop_ip_address, ignore_networks=[frame.ip.src_ip_address])
return self.process_arp_packet(from_nic, frame, route_table, is_reattempt=True)
else:
pass
# TODO: destination unavailable/No ARP netry found
else:
arp_reply = arp_packet.generate_reply(from_nic.mac_address)
self.send_arp_reply(arp_reply, from_nic)
return
class RouterICMP(ICMP):
"""
@@ -613,7 +667,7 @@ class RouterICMP(ICMP):
return
# Route the frame
self.router.route_frame(frame, from_nic)
self.router.process_frame(frame, from_nic)
elif frame.icmp.icmp_type == ICMPType.ECHO_REPLY:
for nic in self.router.nics.values():
@@ -633,7 +687,7 @@ class RouterICMP(ICMP):
return
# Route the frame
self.router.route_frame(frame, from_nic)
self.router.process_frame(frame, from_nic)
class Router(Node):
@@ -720,9 +774,9 @@ class Router(Node):
state["acl"] = (self.acl.describe_state(),)
return state
def route_frame(self, frame: Frame, from_nic: NIC, re_attempt: bool = False) -> None:
def process_frame(self, frame: Frame, from_nic: NIC, re_attempt: bool = False) -> None:
"""
Route a given frame from a source NIC to its destination.
Process a Frame.
:param frame: The frame to be routed.
:param from_nic: The source network interface.
@@ -737,8 +791,10 @@ class Router(Node):
return
if not nic:
self.arp.send_arp_request(frame.ip.dst_ip_address)
return self.route_frame(frame=frame, from_nic=from_nic, re_attempt=True)
self.arp.send_arp_request(
frame.ip.dst_ip_address, ignore_networks=[frame.ip.src_ip_address, from_nic.ip_address]
)
return self.process_frame(frame=frame, from_nic=from_nic, re_attempt=True)
if not nic.enabled:
# TODO: Add sys_log here
@@ -747,15 +803,45 @@ class Router(Node):
if frame.ip.dst_ip_address in nic.ip_network:
from_port = self._get_port_of_nic(from_nic)
to_port = self._get_port_of_nic(nic)
self.sys_log.info(f"Routing frame to internally from port {from_port} to port {to_port}")
self.sys_log.info(f"Forwarding frame to internally from port {from_port} to port {to_port}")
frame.decrement_ttl()
if frame.ip and frame.ip.ttl < 1:
self.sys_log.info("Frame discarded as TTL limit reached")
return
frame.ethernet.src_mac_addr = nic.mac_address
frame.ethernet.dst_mac_addr = target_mac
nic.send_frame(frame)
return
else:
pass
# TODO: Deal with routing from route tables
self._route_frame(frame, from_nic)
def _route_frame(self, frame: Frame, from_nic: NIC, re_attempt: bool = False) -> None:
route = self.route_table.find_best_route(frame.ip.dst_ip_address)
if route:
nic = self.arp.get_arp_cache_nic(route.next_hop_ip_address)
target_mac = self.arp.get_arp_cache_mac_address(route.next_hop_ip_address)
if re_attempt and not nic:
self.sys_log.info(f"Destination {frame.ip.dst_ip_address} is unreachable")
return
if not nic:
self.arp.send_arp_request(frame.ip.dst_ip_address, ignore_networks=[frame.ip.src_ip_address])
return self.process_frame(frame=frame, from_nic=from_nic, re_attempt=True)
if not nic.enabled:
# TODO: Add sys_log here
return
from_port = self._get_port_of_nic(from_nic)
to_port = self._get_port_of_nic(nic)
self.sys_log.info(f"Routing frame to internally from port {from_port} to port {to_port}")
frame.decrement_ttl()
if frame.ip and frame.ip.ttl < 1:
self.sys_log.info("Frame discarded as TTL limit reached")
return
frame.ethernet.src_mac_addr = nic.mac_address
frame.ethernet.dst_mac_addr = target_mac
nic.send_frame(frame)
def receive_frame(self, frame: Frame, from_nic: NIC):
"""
@@ -764,7 +850,7 @@ class Router(Node):
:param frame: The incoming frame.
:param from_nic: The network interface where the frame is coming from.
"""
route_frame = False
process_frame = False
protocol = frame.ip.protocol
src_ip_address = frame.ip.src_ip_address
dst_ip_address = frame.ip.dst_ip_address
@@ -796,12 +882,12 @@ class Router(Node):
self.icmp.process_icmp(frame=frame, from_nic=from_nic)
else:
if src_port == Port.ARP:
self.arp.process_arp_packet(from_nic=from_nic, frame=frame)
self.arp.process_arp_packet(from_nic=from_nic, frame=frame, route_table=self.route_table)
else:
# All other traffic
route_frame = True
if route_frame:
self.route_frame(frame, from_nic)
process_frame = True
if process_frame:
self.process_frame(frame, from_nic)
def configure_port(self, port: int, ip_address: Union[IPv4Address, str], subnet_mask: Union[IPv4Address, str]):
"""