1 files changed, 172 insertions, 0 deletions
diff --git a/tasks/nat_port_forward/task.py b/tasks/nat_port_forward/task.py
new file mode 100644
index 0000000..80d2e47
--- /dev/null
+++ b/tasks/nat_port_forward/task.py
@@ -0,0 +1,172 @@
+# kpov_util should be imported by add_assignment.py
+
+instructions = {
+    'si':"""
+<pre>Postavi tri računalnike - SimpleArbiter z diska simpleArbiter, TestClient z diska testClient in NATServer. NATServer naj ima dva omrežna vmesnika - z enim naj bo
+povezan na omrežje, od koder bo imel dostop do Interneta, z drugim pa na SimpleArbiter. TestClient naj bo povezan na isto omrežje z dostopom do Interneta kot NATServer.
+Poskrbi, da bo NATServer služil kot DHCP strežnik ter privzeti prehod za SimpleArbiter.
+Na SimpleArbiter preberi vrednosti NET, PORT_OUTER in PORT_INNER ter vpiši IP_TEST_CLIENT. Poskrbi, da
+bo omrežje med SimpleArbiter in NATServer na področju NET. Nato poskrbi, da se
+bo TCP promet z omrežja z dostopom do Interneta na vrata PORT_OUTER prepošiljal na SimpleArbiter na vrata PORT_INNER.</pre>"""
+}
+
+computers = {
+    'TestClient': {
+        'disks': [
+            {   'name': 'maliNetworkManager',
+            },
+        ],
+        'network_interfaces': [{'network': 'test-net'}],
+        'flavor': 'm1.tiny',
+        'config_drive': False
+
+    },
+    'NATServer': {
+        'disks': [
+            {   'name': 'student-NATServer',
+            },
+        ],
+        'network_interfaces': [{'network': 'net1'}, {'network': 'test-net'}],
+        'flavor': 'm1.tiny',
+        'config_drive': False
+
+    },
+    'SimpleArbiter': {
+        'disks': [
+            {   'name': 'simpleArbiter',
+            },
+        ],
+        'network_interfaces': [{'network': 'net1'}],
+        'flavor': 'm1.tiny',
+        'config_drive': False
+    }
+}
+
+networks = { 'net1': {'public': False}, 'test-net': {'public': True} }
+
+params_meta = {
+    'IP_TEST_CLIENT': {'descriptions': {'si': 'Naslov TestClient'}, 'w': True, 'public':True, 'type': 'IP', 'generated': False},
+    'IP_NAT': {'descriptions': {'si': 'Naslov NATServer, dostopen s TestClient'}, 'w': True, 'public':True, 'type': 'IP', 'generated': False},
+    'PORT_OUTER': {'descriptions': {'si': 'Zunanja vrata'}, 'w': False, 'public':True, 'type': 'port', 'generated': True},
+    'PORT_INNER': {'descriptions': {'si': 'Notranja vrata'}, 'w': False, 'public': True, 'type': 'port', 'generated': True},
+    'NET': {'descriptions': {'si': 'Področje naslovov med SimpleArbiter in TestClient'}, 'w': False, 'public': True, 'type': 'NET', 'generated': True},
+}
+
+def task(IP_TEST_CLIENT, IP_NAT, PORT_OUTER, PORT_INNER, NET):
+    import random
+    import time
+    import pexpect
+    from pexpect import pxssh
+
+    results = dict()
+    tcpdump = pexpect.spawn('sudo /usr/sbin/tcpdump src host {} and dst port {}'.format(IP_TEST_CLIENT, PORT_INNER), encoding='utf-8')
+    sshconn = pxssh.pxssh(encoding='utf-8')
+    sshconn.login(IP_TEST_CLIENT, 'student', 'vaje')
+    r = random.Random()
+    k = r.randint(10, 15)
+    results['pre_nc'] = str(k)
+    results['nc_pre'] = ""
+    for i in range(k):
+        sshconn.sendline("nc {} {}".format(IP_NAT, PORT_OUTER))
+        sshconn.sendline()
+        sshconn.sendintr()
+        sshconn.prompt()
+        results['nc_pre'] += sshconn.before
+    nc = pexpect.spawn('nc -l -p {}'.format(PORT_INNER), encoding='utf-8')
+    sshconn.sendline()
+    sshconn.prompt()
+    sshconn.sendline("nc {} {}".format(IP_NAT, PORT_OUTER))
+    results['post_nc'] = "".join([r.choice("abcd\n") for i in range(100)])
+    sshconn.sendline(results['post_nc'])
+    time.sleep(1)
+    sshconn.sendintr()
+    nc.expect(pexpect.EOF)
+    results['nc_ret'] = nc.before
+    results['route'] = pexpect.run('ip route list 0/0', encoding='utf-8')
+    results['traceroute'] = pexpect.run('traceroute {}'.format(IP_TEST_CLIENT), encoding='utf-8')
+    # wait for traceroute
+    time.sleep(10)
+    tcpdump.sendintr()
+    tcpdump.expect(pexpect.EOF)
+    results['tcpdump'] = tcpdump.before
+    sshconn.prompt()
+    results['nc_post'] = sshconn.before
+    sshconn.close()
+    # nc.expect(pexpect.EOF)
+    return results
+    
+def gen_params(user_id, params_meta):
+    params = dict()
+    r = random.Random(user_id)
+    params['PORT_INNER'] = str(r.randint(6000, 10000))
+    params['PORT_OUTER'] = str(r.randint(10001, 15000))
+    params['NET'] = kpov_util.IPv4_subnet_gen(r, "10.36.0.0/14", 24)
+    return params
+
+def task_check(results, params):
+    import re
+    import pickle
+    score = 0
+    hints = []
+    local_net = params['NET'][:params['NET'].rfind('.')]
+    s = "default via ({}\\.[0-9]+)".format(re.escape(local_net))
+    res = re.search(s, results['route'])
+    if res:
+        ip_nat_internal = res.groups(1)[0]
+        score += 1
+    else:
+        ip_nat_internal = 'abrakadabra'
+    #    print (s, results['route'],)
+    s = "traceroute to {ip_test} \\({ip_test}\\), 30 hops max, 60 byte packets\
+\r\n 1  {ip_nat} \\({ip_nat}\\)  [0-9.]+ ms  [0-9.]+ ms  [0-9.]+ ms\
+.*{ip_test} \\({ip_test}\\)".format(
+        ip_nat = re.escape(ip_nat_internal), 
+        ip_test = re.escape(params['IP_TEST_CLIENT'])
+    )
+    if re.search(s, results['traceroute'], re.DOTALL):
+        score += 1
+    else:
+        hints += [s + str(results['traceroute'])]
+    if len(results['post_nc']) == 100:
+        score += 1
+    else:
+        hints += [str(results['post_nc']) + str(len(results['post_nc']))]
+    if results['nc_ret'] == (results['post_nc'] + '\n').replace('\n', '\r\n'):
+        score += 1
+    else:
+        hints += ['wrong nc']
+    s = "Connection refused"
+    res = re.findall(s, results['nc_pre'])
+    if len(res) >= 2:
+        score += 3
+    else:
+        hints += [s + str(results['nc_pre'])]
+    s = "\r\n"
+    if re.search(s, results['nc_post']):
+        score += 1
+    else:
+        hints += [s + str(results['nc_post'])]
+    rejected_count = int(results['pre_nc'])
+    accepted_count = results['nc_ret'].count('\r\n')
+    s = ".*verbose output suppressed.*listening on.*dropped by kernel.*"
+    if re.match(s, results['tcpdump'], re.DOTALL):
+        score += 1
+    else:
+        hints += [s + str(results['tcpdump'])]
+    res = re.findall("length .*\r\n", results['tcpdump'])
+    total_len = 0
+    n_empty = 0
+    for i in res:
+        k = int(i[len("length "):].strip())
+        total_len += k
+        if k == 0:
+            n_empty += 1
+    # print total_len, rejected_count, n_empty
+    if total_len == 101 and rejected_count <= n_empty:
+        score += 1
+    else:
+        hints += [s + str(results['tcpdump'])]
+    return score, hints
+
+def prepare_disks(templates, task_params, global_params):
+    write_default_config(templates['simpleArbiter'], global_params)