Begin conversion of pxe to asyncio

Also convert to 'natural' recvmsg now that we are requiring
python high enough to have it.

confluent_server/confluent/discovery/protocols/pxe.py

@@ -22,6 +22,7 @@
 
 # option 97 = UUID (wireformat)
 
+import asyncio
 import confluent.config.configmanager as cfm
 import confluent.collective.manager as collective
 import confluent.noderange as noderange
@@ -273,58 +274,49 @@ def opts_to_dict(rq, optidx, expectype=1):
 def ipfromint(numb):
     return socket.inet_ntoa(struct.pack('I', numb))
 
-def proxydhcp(handler, nodeguess):
+def relay_proxydhcp(sock, pktq):
+    sock.setblocking(0)
+    data, cmsgs, flags, peer = sock.recvmsg(9000, 9000)
+    if len(data) < 240:
+        return
+    try:
+        optidx = data.index(b'\x63\x82\x53\x63') + 4
+    except ValueError:
+        return
+    for cmsg in cmsgs:
+        level, typ, cdata = cmsg
+        if level == socket.IPPROTO_IP and typ == IP_PKTINFO:
+            idx, recv = struct.unpack('II', cdata[:8])
+            recv = ipfromint(recv)
+            break
+    else:
+        return
+    rq = memoryview(data)
+    hwlen = rq[2]
+    opts, disco = opts_to_dict(rq, optidx, 3)
+    disco['hwaddr'] = ':'.join(['{0:02x}'.format(x) for x in rq[28:28+hwlen]])
+    node = None
+    if disco.get('hwaddr', None) in macmap:
+        node = macmap[disco['hwaddr']]
+    elif disco.get('uuid', None) in uuidmap:
+        node = uuidmap[disco['uuid']]
+    myipn = myipbypeer.get(data[28:28+hwlen], None)
+    skiplogging = True
+    pktq.put_nowait((disco, peer, myipn, idx, recv, node, opts, data))
+
+
+async def proxydhcp(handler, nodeguess):
     net4011 = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
     net4011.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
     net4011.setsockopt(socket.IPPROTO_IP, IP_PKTINFO, 1)
     net4011.bind(('', 4011))
-    rp = bytearray(300)
-    rpv = memoryview(rp)
-    rq = bytearray(2048)
-    data = pkttype.from_buffer(rq)
-    msg = msghdr()
-    cmsgarr = bytearray(cmsgsize)
-    cmsg = cmsgtype.from_buffer(cmsgarr)
-    iov = iovec()
-    iov.iov_base = ctypes.addressof(data)
-    iov.iov_len = 2048
-    msg.msg_iov = ctypes.pointer(iov)
-    msg.msg_iovlen = 1
-    msg.msg_control = ctypes.addressof(cmsg)
-    msg.msg_controllen = ctypes.sizeof(cmsg)
-    clientaddr = sockaddr_in()
-    msg.msg_name = ctypes.addressof(clientaddr)
-    msg.msg_namelen = ctypes.sizeof(clientaddr)
+    cloop = asyncio.get_running_loop()
+    pktq = asyncio.Queue()
+    cloop.add_reader(net4011, relay_proxydhcp, net4011, pktq)
     cfg = cfm.ConfigManager(None)
     while True:
         try:
-            ready = select.select([net4011], [], [], None)
-            if not ready or not ready[0]:
-                continue
-            i = recvmsg(net4011.fileno(), ctypes.pointer(msg), 0)
-            #nb, client = net4011.recvfrom_into(rq)
-            if i < 240:
-                continue
-            rqv = memoryview(rq)[:i]
-            client = (ipfromint(clientaddr.sin_addr.s_addr), socket.htons(clientaddr.sin_port))
-            _, level, typ = struct.unpack('QII', cmsgarr[:16])
-            if level == socket.IPPROTO_IP and typ == IP_PKTINFO:
-                idx, recv = struct.unpack('II', cmsgarr[16:24])
-                recv = ipfromint(recv)
-            try:
-                optidx = rqv.tobytes().index(b'\x63\x82\x53\x63') + 4
-            except ValueError:
-                continue
-            hwlen = rq[2]
-            opts, disco = opts_to_dict(rq, optidx, 3)
-            disco['hwaddr'] = ':'.join(['{0:02x}'.format(x) for x in rq[28:28+hwlen]])
-            node = None
-            if disco.get('hwaddr', None) in macmap:
-                node = macmap[disco['hwaddr']]
-            elif disco.get('uuid', None) in uuidmap:
-                node = uuidmap[disco['uuid']]
-            myipn = myipbypeer.get(rqv[28:28+hwlen].tobytes(), None)
-            skiplogging = True
+            disco, client, myipn, idx, recv, node, opts, data = await pktq.get()
             netaddr = disco['hwaddr']
             if time.time() > ignoredisco.get(netaddr, 0) + 90:
                 skiplogging = False
@@ -375,6 +367,9 @@ def proxydhcp(handler, nodeguess):
                     'for this boot method.'.format(
                         node, profile, len(bootfile) - 127)})
                 continue
+            rp = bytearray(300)
+            rpv = memoryview(rp)
+            rqv = memoryview(data)
             rpv[:240] = rqv[:240].tobytes()
             rpv[0:1] = b'\x02'
             rpv[108:108 + len(bootfile)] = bootfile
@@ -390,15 +385,16 @@ def proxydhcp(handler, nodeguess):
 
 
 def start_proxydhcp(handler, nodeguess=None):
-    eventlet.spawn_n(proxydhcp, handler, nodeguess)
+    util.spawn(proxydhcp(handler, nodeguess))
 
 
-def snoop(handler, protocol=None, nodeguess=None):
+async def snoop(handler, protocol=None, nodeguess=None):
     #TODO(jjohnson2): ipv6 socket and multicast for DHCPv6, should that be
     #prominent
     #TODO(jjohnson2): enable unicast replies. This would suggest either
     # injection into the neigh table before OFFER or using SOCK_RAW.
     start_proxydhcp(handler, nodeguess)
+    global tracelog
     tracelog = log.Logger('trace')
     global attribwatcher
     cfg = cfm.ConfigManager(None)