reorganize LAN chat stuff

lan-chat/bccplus.py

@@ -0,0 +1,221 @@
+#!/usr/bin/env python3
+
+import socket
+import threading
+import time
+import sys
+import subprocess
+import os
+import collections
+import getpass
+import re
+import random
+import ipaddress
+import itertools
+import struct
+
+PORT = 44718
+IPPROTO_IPV6 = getattr(socket, "IPPROTO_IPV6") if "IPPROTO_IPV6" in dir(socket) else 41 # workaround for weird Windows/old Python quirk
+
+maddr = ("ff15::aeae", 44718)
+
+def configure_multicast(maddr, ifn):
+    mip, port = maddr
+    haddr = socket.getaddrinfo("::", port, socket.AF_INET6, socket.SOCK_DGRAM)[0][-1]
+    maddr = socket.getaddrinfo(mip, port, socket.AF_INET6, socket.SOCK_DGRAM)[0][-1]
+
+    sock = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM)
+
+    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+    if hasattr(socket, "SO_REUSEPORT"):
+        sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
+
+    sock.setsockopt(IPPROTO_IPV6, socket.IPV6_MULTICAST_LOOP, 1)
+    sock.setsockopt(IPPROTO_IPV6, socket.IPV6_MULTICAST_HOPS, 5)
+
+    ifn = struct.pack("I", ifn)
+    sock.setsockopt(IPPROTO_IPV6, socket.IPV6_MULTICAST_IF, ifn)
+
+    group = socket.inet_pton(socket.AF_INET6, mip) + ifn
+    sock.setsockopt(IPPROTO_IPV6, socket.IPV6_JOIN_GROUP, group)
+
+    sock.bind(haddr)
+
+    return sock, maddr
+
+def chunks(l, n):
+    n = max(1, n)
+    return [l[i:i+n] for i in range(0, len(l), n)]
+
+def recv(q, iface):
+    s, _ = configure_multicast(maddr, iface)
+
+    while True:
+        data, peer = s.recvfrom(2048)
+        peer = peer[0].split("%")[0], peer[1]
+        q.put((data, peer))
+
+def normalize_ip(ip):
+    return str(ipaddress.ip_address(ip))
+
+def shorthex(x): return "{:04x}".format(x)
+def encode_packet(ty, nick, content):
+    return struct.pack("!BH16s", ty, local_id, nick.encode("utf-8")) + content.encode("utf-8")
+def decode_packet(pkt):
+    ty, local_id, nick = struct.unpack("!BH16s", pkt[:19])
+    content = pkt[19:]
+    return ty, local_id, nick.rstrip(b"\0").decode("utf-8"), content.decode("utf-8")
+
+MTY_PING = 0
+MTY_MESSAGE = 1
+
+if __name__ == "__main__":
+    mynick = getpass.getuser() + "@" + socket.gethostname()
+    peers = {}
+    local_id = random.randint(0, 0xFFFF)
+
+    # dark horrors, TODO refactor into more consistent interface (no pun intended)
+    if sys.platform.startswith("win32"):
+        out = subprocess.check_output(["ipconfig"])
+        match = re.search(b"\n +Link-local IPv6 Address[ .]: ([a-f0-9:])%([0-9]+)", out)
+        own_ips = {match.group(1)}
+        iface = int(match.group(2))
+        for match in re.findall(b"\n +IPv6 Address[ .]: ([a-f0-9:])", out):
+            own_ips.add(match.group(1))
+    else:
+        try:
+            raise PermissionError
+            addrs = collections.defaultdict(set)
+            for line in open("/proc/net/if_inet6").readlines():
+                addr, ifnum, _, _, _, ifname = line.split()
+                ifnum = int(ifnum, 16)
+                addr = normalize_ip(":".join(chunks(addr, 4)))
+                addrs[ifnum].add(addr)
+                if ("wlan" in ifname or ifname.startswith("en") or ifname.startswith("eth")) and addr.startswith("fe80"):
+                    iface = ifnum
+            if not iface: raise SystemExit("No suitable interface found, suffer")
+            own_ips = addrs[iface]
+        except PermissionError:
+            out =  subprocess.check_output(["ip", "addr", "show"]).decode("ascii")
+            addrs = collections.defaultdict(set)
+            for line in out.split("\n"):
+                match = re.match("([0-9]+): ([A-Za-z0-9-_]+):", line)
+                if match:
+                    num, ifname = int(match.group(1)), match.group(2)
+                    current_if = num
+                    if "wlan" in ifname or ifname.startswith("en") or ifname.startswith("eth"):
+                        iface = num
+                match = re.match(" +inet6 ([a-z0-9:]+)/", line)
+                if match:
+                    addrs[current_if].add(match.group(1))
+            own_ips = addrs[iface]
+
+    print("IP:", own_ips, "Iface:", ifname or iface, "LocID:", shorthex(local_id))
+
+    proc = None
+    if sys.platform.startswith("win32"):
+        from multiprocessing import Process, Queue
+        packet_queue = Queue()
+        proc = Process(target=recv, args=(packet_queue, iface))
+        proc.start()
+    else:
+        import queue
+        packet_queue = queue.Queue()
+        thread = threading.Thread(target=recv, args=(packet_queue, iface)).start()
+
+    def queuereader():
+        while True:
+            data, (remote_addr, _) = packet_queue.get()
+            try:
+                ty, remote_local_id, nick, content = decode_packet(data)
+                if remote_addr in own_ips and remote_local_id == local_id: continue
+                peer_id = remote_addr + "/" + shorthex(remote_local_id)
+                try:
+                    peer = peers[peer_id]
+                    peer["ping_countdown"] = 5
+                    if nick != peer["nick"]:
+                        print("! %s (%s) is now %s" % (peer["nick"], peer_id, nick))
+                        peer["nick"] = nick
+                except KeyError:
+                    print("! %s (%s) now exists" % (nick, peer_id))
+                    peers[peer_id] = { "nick": nick, "ping_countdown": 5 }
+                if ty == MTY_MESSAGE:
+                    print(nick + ": " + content)
+            except Exception as e:
+                print("Parse error", e)
+
+    s, dest = configure_multicast(maddr, iface)
+
+    def pinger():
+        while True:
+            s.sendto(encode_packet(MTY_PING, mynick, ""), dest)
+            for id, peer in list(peers.items()):
+                peer["ping_countdown"] -= 1
+                if peer["ping_countdown"] <= 0:
+                    del peers[id]
+                    print("! %s (%s) no longer exists" % (peer["nick"], id))
+            time.sleep(1)
+
+    threading.Thread(target=queuereader).start()
+    threading.Thread(target=pinger).start()
+
+    try:
+        while True:
+            msg = input("> ")
+            if msg.startswith("/nick "):
+                newnick = msg[6:]
+                if len(newnick.encode("utf-8")) > 16:
+                    print("! Max nick length is 16 bytes")
+                else:
+                    print("! You are now", newnick)
+                    mynick = newnick
+            elif msg.startswith("/peer"):
+                p = ["%s (%s)" % (i, p["nick"]) for i, p in peers.items()]
+                print("! Peers:", " ".join(p))
+            else:
+                s.sendto(encode_packet(MTY_MESSAGE, mynick, msg), dest)
+                time.sleep(0.05)
+    except KeyboardInterrupt:
+        if proc: proc.terminate()
+        os._exit(0)
+
+# in case of things
+"""
+AF_INET AddressFamily.AF_INET
+AF_INET6 AddressFamily.AF_INET6
+IPPROTO_IPV6 41
+IPV6_CHECKSUM 7
+IPV6_DONTFRAG 62
+IPV6_DSTOPTS 59
+IPV6_HOPLIMIT 52
+IPV6_HOPOPTS 54
+IPV6_JOIN_GROUP 20
+IPV6_LEAVE_GROUP 21
+IPV6_MULTICAST_HOPS 18
+IPV6_MULTICAST_IF 17
+IPV6_MULTICAST_LOOP 19
+IPV6_NEXTHOP 9
+IPV6_PATHMTU 61
+IPV6_PKTINFO 50
+IPV6_RECVDSTOPTS 58
+IPV6_RECVHOPLIMIT 51
+IPV6_RECVHOPOPTS 53
+IPV6_RECVPATHMTU 60
+IPV6_RECVPKTINFO 49
+IPV6_RECVRTHDR 56
+IPV6_RECVTCLASS 66
+IPV6_RTHDR 57
+IPV6_RTHDRDSTOPTS 55
+IPV6_RTHDR_TYPE_0 0
+IPV6_TCLASS 67
+IPV6_UNICAST_HOPS 16
+IPV6_V6ONLY 26
+SOL_ALG 279
+SOL_HCI 0
+SOL_IP 0
+SOL_RDS 276
+SOL_SOCKET 1
+SOL_TCP 6
+SOL_TIPC 271
+SOL_UDP 17
+"""