commit 6ca16fc624bd426c5fae5dae6652899d5a0f66ef
Author: Trinity Pointard <trinity.pointard@gmail.com>
Date:   Wed Nov 3 09:19:53 2021 +0100

    init

diff --git a/config.yml b/config.yml
new file mode 100644
index 0000000..3ff5b80
--- /dev/null
+++ b/config.yml
@@ -0,0 +1,46 @@
+links:
+  - &100
+    bandwidth: 100M
+    latency: 2ms
+  - &1000
+    bandwidth: 1000M
+    latency: 1ms
+  - &vdsl
+    bandwidth:
+      up: 3M
+      down: 55M
+    latency: 50ms
+    jitter: 10ms
+  - &fiber
+    bandwidth: 400M
+    latency: 10ms
+    jitter: 3ms
+
+zones:
+  - &dc1
+    name: dc1
+    internal: *100
+    external: *vdsl
+  - &dc2
+    name: dc2
+    internal: *1000
+    external: *fiber
+
+servers:
+  - name: dc1s1
+    zone: *dc1
+  - name: dc1s2
+    zone: *dc1
+  - name: dc2s1
+    zone: *dc2
+  - name: dc2s2
+    zone: *dc2
+  - name: no_dc
+    <<: *vdsl
+
+global:
+  subnet:
+    base: 172.24.0.0
+    local: 8
+    zone: 8
+  latency-offset: 3ms
diff --git a/main.py b/main.py
new file mode 100755
index 0000000..e50e088
--- /dev/null
+++ b/main.py
@@ -0,0 +1,338 @@
+#!/bin/env python
+import ipaddress
+import os
+import shutil
+import subprocess
+import sys
+import yaml
+from pyroute2 import NDB, netns
+
+class SubnetManager:
+    def __init__(self, config):
+        self.base = config['base']
+        self.zone_size = config['zone']
+        self.local_size = config['local']
+        if ipaddress.ip_address(self.base).version == 6:
+            self.prefix = 128 - self.zone_size - self.local_size
+        else:
+            self.prefix = 32 - self.zone_size - self.local_size
+        self.networks = ipaddress.ip_network((self.base, self.prefix)).subnets(self.zone_size)
+
+        self.current_net = next(self.networks).hosts()
+
+    def next_local(self):
+        return next(self.current_net)
+
+    def next_zone(self):
+        self.current_net = next(self.networks).hosts()
+
+    def __str__(self):
+        return f'SubnetManager{{base: {self.base}, zone: {self.zone_size}, local: {self.local_size}}}'
+
+class Latency:
+    def __init__(self, latency, offset = None):
+        if type(latency) is int:
+            self.latency_ms = latency
+        else:
+            for suffix, factor in [("ms", 1), ("s", 1000), ("m", 60 * 1000)]:
+                if latency.endswith(suffix):
+                    self.latency_ms = int(float(latency[:-len(suffix)]) * factor)
+                    break
+            else:
+                self.latency_ms = int(latency)
+        if offset:
+            self.latency_ms -= Latency(offset).latency_ms
+        if self.latency_ms < 0:
+            self.latency_ms = 0
+
+    def __eq__(self, o):
+        return isinstance(o, Latency) and o.latency_ms == self.latency_ms
+
+    def __str__(self):
+        return f'{self.latency_ms}ms'
+
+class Bandwidth:
+    def __init__(self, bw):
+        def convert(bw):
+            factor = 1
+            for suffix, f in [("bit", 1), ("bps",1), ("b", 1), ("byte", 8), ("Byte",8), ("B", 8)]:
+                if bw.endswith(suffix):
+                    bw = bw[:-len(suffix)]
+                    factor = f
+                    break
+
+            for suffix, f in [("k", 1000), ("ki", 1024), ("m", 1000**2), ("mi", 1024**2), ("g", 1000**3), ("gi", 1024**3)]:
+                if bw.lower().endswith(suffix):
+                    return int(float(bw[:-len(suffix)]) * factor * f)
+            else:
+                return int(float(bw) * factor)
+        if type(bw) is dict:
+            self.down = convert(bw["down"])
+            self.up = convert(bw["up"])
+        else:
+            self.down = convert(bw)
+            self.up = convert(bw)
+
+    def __str__(self):
+        def convert(bw):
+            for suffix, factor in [("g", 1000**3), ("m", 1000**2), ("k", 1000)]:
+                if bw > 10 * factor:
+                    return f'{bw/factor:.1f}{suffix}bps'
+        return f'{convert(self.down)}/{convert(self.up)}'
+
+    def __eq__(self, o):
+        return (isinstance(o, Bandwidth) and
+                o.down == self.down and
+                o.up == self.up)
+        
+
+class LinkInfo:
+    def __init__(self, bandwidth, latency, jitter = None, offset = None, **kwargs):
+        self.bandwidth = Bandwidth(bandwidth)
+        self.latency = Latency(latency, offset)
+        self.jitter = Latency(jitter or 0)
+
+    def __eq__(self, o):
+        return (isinstance(o, LinkInfo) and 
+            o.bandwidth == self.bandwidth and
+            o.latency == self.latency and
+            o.jitter == self.jitter)
+
+    def __str__(self):
+        return f'LinkInfo{{bw: {self.bandwidth}, latency: {self.latency}, jitter: {self.jitter}}}'
+
+class Server:
+    def __init__(self, name, link):
+        self.ip = None
+        self.name = name
+        self.link = link
+    
+    def is_zone(self):
+        return False
+
+    def __str__(self):
+        return f'Server{{name: {self.name}, ip: {self.ip}, link: {self.link}}}'
+
+    def __repr__(self):
+        return self.__str__()
+
+class Zone:
+    def __init__(self, name):
+        self.name = name
+        self.link = None
+        self.servers = {}
+
+    def is_zone(self):
+        return True
+
+    def add_server(self, server):
+        if self.servers.get(server.name) is None:
+            self.servers[server.name] = server
+        else:
+            raise Exception(f"Duplicate server '{server.name}' in zone '{self.name}'")
+
+    def set_link(self, link):
+        if self.link is None:
+            self.link = link
+        elif self.link != link:
+            raise Exception(f"Uncoherent link configuration for zone '{self.name}'")
+
+    def __str__(self):
+        return f'Zone{{name: {self.name}, link: {self.link}, servers: {list(self.servers.values())}}}'
+
+    def __repr__(self):
+        return self.__str__()
+
+
+class Network:
+    def __init__(self):
+        self.zones = {}
+        self.subnet_manager = None
+        self.latency_off = Latency(0)
+
+    def set_subnet_manager(self, subnet):
+        self.subnet_manager = SubnetManager(subnet)
+
+    def set_latency_offset(self, latency_off):
+        self.latency_off = latency_off
+
+    def add_server(self, server):
+        name = server["name"]
+        if zone_obj := server.get("zone"):
+            zone_name = zone_obj["name"]
+            if zone := self.zones.get(zone_name):
+                if not zone.is_zone():
+                    raise Exception("Duplicate zone: " + name)
+            else:
+                zone = Zone(zone_name)
+                self.zones[zone_name] = zone
+            if link:=zone_obj.get("external"):
+                zone.set_link(LinkInfo(offset = self.latency_off, **link))
+            zone.add_server(Server(name, LinkInfo(**zone_obj["internal"])))
+
+        else:
+            name = name
+            if name in self.zones:
+                raise Exception("Duplicate zone: " + name)
+            self.zones[name] = Server(name, LinkInfo(offset = self.latency_off, **server))
+
+    def assign_ips(self):
+        for zone in self.zones.values():
+            if zone.is_zone(): 
+                for server in zone.servers.values():
+                    server.ip = self.subnet_manager.next_local()
+            else:
+                zone.ip = self.subnet_manager.next_local()
+            self.subnet_manager.next_zone()
+
+    def __str__(self):
+        return f'Network{{subnet_manager: {self.subnet_manager}, zones: {list(self.zones.values())}, latency_offset: {self.latency_off}}}'
+
+class NamespaceManager:
+    def __init__(self):
+        self.ndb = NDB(log='debug')
+        self.namespaces = set()
+
+    def make_namespace(self, name):
+        if not name in self.namespaces:
+            self.namespaces.add(name)
+            self.ndb.sources.add(netns=name)
+
+    def make_bridge(self, name, namespace):
+        self.make_namespace(namespace)
+        return (self.ndb.interfaces.create(ifname=name, kind='bridge', target=namespace)
+            .set('state', 'up'))
+        
+    def make_veth(self, name1, name2, space1, space2, ip, link):
+        self.make_namespace(space1)
+        self.make_namespace(space2)
+        veth = (self.ndb.interfaces.create(ifname=name1, target=space1, kind='veth',
+                peer={'ifname': name2, 'net_ns_fd': space2})
+                .set('state', 'up'))
+        if ip:
+            veth.add_ip(address=str(ip), prefixlen=self.prefixlen)
+        veth.commit()
+        #NSPopen(space1, ['tc', 'qdisc', 'add', 'dev', nam1, 'root', 'netem', 'delay', '1000ms', '0ms'])
+        #add the other way too
+
+    def build_network(self, network):
+        self.prefixlen = network.subnet_manager.prefix
+        netns = "testnet-core"
+        bridge = self.make_bridge("br0", netns)
+        for zone in network.zones.values():
+            if zone.is_zone():
+                self.build_zone(zone)
+            else:
+                self.build_server(zone)
+            bridge.add_port({'ifname': 'veth-' + zone.name, 'target': netns})
+        bridge.commit()
+
+    def build_zone(self, zone):
+        netns = "testnet-" + zone.name
+        bridge = self.make_bridge("br-" + zone.name, netns)
+        self.make_veth("veth-" + zone.name, "veth-" + zone.name, netns, "testnet-core", None, zone.link)
+        bridge.add_port({'ifname': 'veth-' + zone.name, 'target': netns})
+        for server in zone.servers.values():
+            self.build_server(server, zone)
+            bridge.add_port({'ifname': 'veth-' + server.name, 'target': netns})
+        bridge.commit()
+
+    def build_server(self, server, zone = None):
+        if zone:
+            zone_name = "testnet-" + zone.name
+        else:
+            zone_name = "testnet-core"
+        namespace = zone_name + "-" + server.name
+        self.make_veth("veth", "veth-" + server.name, namespace, zone_name, server.ip, server.link)
+
+    def close(self):
+        self.ndb.close()
+
+def parse(yaml):
+    server_list = yaml["servers"]
+    global_conf = yaml.get("global", {})
+    subnet = global_conf.get("subnet", {'base': 'fc00:9a7a:9e::', 'local': 64, 'zone': 16})
+    latency_offset = global_conf.get("latency-offset", 0)
+
+    network = Network()
+    network.set_subnet_manager(subnet)
+    network.set_latency_offset(latency_offset)
+    for server in server_list:
+        network.add_server(server)
+    network.assign_ips()
+    return network
+
+def create(config_path):
+    with open(config_path, "r") as file:
+        config = yaml.safe_load(file)
+        shutil.copy(config_path, ".current_state.yml")
+    network = parse(config)
+    nsm = NamespaceManager()
+    nsm.build_network(network)
+    nsm.close()
+
+def run(netns, cmd):
+    if ":" in netns:
+        zone_name,host = netns.split(":", 1)
+    else:
+        zone_name,host = None, netns
+    with open(".current_state.yml", "r") as file:
+        config = yaml.safe_load(file)
+    zones = parse(config).zones
+    server = None
+    zone = None
+    if zone_name:
+        if (zone := zones.get(zone_name)) and zone.is_zone():
+            server = zone.servers.get(host)
+    elif (zone := zones.get(host)) and not zone.is_zone():
+        server = zone
+    else:
+        for z in zones.values():
+            if not z.is_zone(): continue
+            if (s := z.servers.get(host)):
+                if server:
+                    raise Exception("Multiple matching host found.")
+                server = s
+                zone = z
+
+    if not server:
+        raise Exception("No matching host was found")
+
+    env = os.environ.copy()
+    env["HOST"] = server.name
+    if zone.is_zone():
+        env["ZONE"] = zone.name
+    env["IP"] = str(server.ip)
+    name = f'testnet-{zone.name}-{server.name}'
+
+    if len(cmd) == 0:
+        cmd = [os.getenv("SHELL") or "/bin/sh"]
+    os.execve("/bin/env", ["/bin/env", "ip", "netns" , "exec", name ] + cmd, env)
+
+
+def destroy():
+    for ns in netns.listnetns():
+        if ns.startswith("testnet-"):
+            subprocess.run(f"ip netns pids {ns} | xargs -r kill", check=True, shell=True)
+            netns.remove(ns)
+    os.remove(".current_state.yml")
+
+if __name__ == "__main__":
+    if len(sys.argv) < 2:
+        print("""Usage:
+    mk-testnet create [config_path] # create a new network. config_path defailt to config.yml
+    mk-testnet run-all <cmd> [args...] # run a command as each host. set the IP, NAME and ZONE environment variables
+    mk-testnet run <name> [cmd [args...]] # run command in host named <name>. Use zonename:name if multiple zones hosts server with same name. If cmd is empty, run a shell
+    mk-testnet destroy # destroy the current environment""")
+        exit()
+    cmd = sys.argv[1]
+    if cmd == "create":
+        create(sys.argv[2] if len(sys.argv) > 2 else "config.yml")
+    elif cmd == "run-all":
+        runall(sys.argv[2:])
+    elif cmd == "run":
+        run(sys.argv[2], sys.argv[3:])
+    elif cmd == "destroy":
+        destroy()    
+    else:
+        raise Exception(f"Unknown command: {cmd}")