add test-fortinet-login.py

Often easier to prototype HTTPS-based authentication flows in Python, since
they're so fiddly and arbitary.  So I copied `test-f5-login.py` to
`test-fortinet-login.py`.  Currently only handles basic
username-and-password auth, no 2FA:

```
usage: test-fortinet-login.py [-h] [-v] [-u USERNAME] [-p PASSWORD] [-r REALM]
                              [-c CERT] [--key KEY] [--no-verify]
                              endpoint [extra [extra ...]]

positional arguments:
  endpoint              Fortinet server (or complete URL, e.g.
                        https://forti.vpn.com/remote/login)
  extra                 Extra field to pass to include in the login query
                        string (e.g. "foo=bar")

optional arguments:
  -h, --help            show this help message and exit
  -v, --verbose
  --no-verify           Ignore invalid server certificate

Login credentials:
  -u USERNAME, --username USERNAME
                        Username (will prompt if unspecified)
  -p PASSWORD, --password PASSWORD
                        Password (will prompt if unspecified)
  -r REALM, --realm REALM
                        Realm (empty if unspecified)
  -c CERT, --cert CERT  PEM file containing client certificate (and optionally
                        private key)
  --key KEY             PEM file containing client private key (if not
                        included in same file as certificate)
```

Signed-off-by: Daniel Lenski <dlenski@gmail.com>

diff --git a/test-fortinet-login.py b/test-fortinet-login.py
new file mode 100755 (executable)
index 0000000..631bcb6
--- /dev/null
+++ b/test-fortinet-login.py
@@ -0,0 +1,94 @@
+#!/usr/bin/python3
+
+from __future__ import print_function
+from sys import stderr, version_info
+import requests
+import argparse
+import getpass
+from shlex import quote
+if (version_info >= (3, 0)):
+    from urllib.parse import urlparse, urlencode
+    raw_input = input
+    import http.client as httplib
+else:
+    from urlparse import urlparse
+    import httplib
+
+p = argparse.ArgumentParser()
+p.add_argument('-v', '--verbose', default=0, action='count')
+p.add_argument('endpoint', help='Fortinet server (or complete URL, e.g. https://forti.vpn.com/remote/login)')
+p.add_argument('extra', nargs='*', help='Extra field to pass to include in the login query string (e.g. "foo=bar")')
+g = p.add_argument_group('Login credentials')
+g.add_argument('-u','--username', help='Username (will prompt if unspecified)')
+g.add_argument('-p','--password', help='Password (will prompt if unspecified)')
+g.add_argument('-r','--realm', default='', help='Realm (empty if unspecified)')
+g.add_argument('-c','--cert', help='PEM file containing client certificate (and optionally private key)')
+g.add_argument('--key', help='PEM file containing client private key (if not included in same file as certificate)')
+p.add_argument('--no-verify', dest='verify', action='store_false', default=True, help='Ignore invalid server certificate')
+args = p.parse_args()
+
+if args.verbose > 1:
+    httplib.HTTPConnection.debuglevel = 1
+
+extra = dict(x.split('=', 1) for x in args.extra)
+endpoint = urlparse(('https://{}/remote/login'.format(args.endpoint) if '//' not in args.endpoint else args.endpoint), 'https:')
+
+if args.cert and args.key:
+    cert = (args.cert, args.key)
+elif args.cert:
+    cert = (args.cert, None)
+elif args.key:
+    p.error('--key specified without --cert')
+else:
+    cert = None
+
+s = requests.Session()
+s.cert = cert
+s.verify = args.verify
+s.headers['User-Agent'] = 'Open AnyConnect VPN Agent v8.x' # seems to result in a more machine-parseable response format than 'Mozilla/5.0 SV1'
+s.headers['Accept-Encoding'] = 'identity'                  # these servers appear to bork 'Transfer-Encoding: chunked'
+
+print("Initial GET /remote/login to populate cookies...", file=stderr)
+res = s.get(endpoint.geturl(), allow_redirects=False)
+
+# Send login credentials
+if args.username == None:
+    args.username = raw_input('Username: ')
+if args.password == None:
+    args.password = getpass.getpass('Password: ')
+data=dict(username=args.username, credential=args.password, realm=args.realm,
+         ajax=1, redir='%2Fremote%2Findex', just_logged_in=1,
+          **extra)
+print("POST /remote/logincheck to submit login credentials...", file=stderr)
+res = s.post(endpoint._replace(path='/remote/logincheck').geturl(), data=data)
+
+res.raise_for_status()
+
+# Build openconnect --cookie argument from the result:
+url = urlparse(res.url)
+if any(c.name=='SVPNCOOKIE' and c.value for c in s.cookies):
+    cookie = next(c.value for c in s.cookies if c.name=='SVPNCOOKIE')
+    if args.verbose:
+        if cert:
+            cert_and_key = ' \\\n        ' + ' '.join('%s "%s"' % (opt, quote(fn)) for opt, fn in zip(('-c','-k'), cert) if fn)
+        else:
+            cert_and_key = ''
+
+        print('''
+Extracted connection cookie. Use this to connect:
+
+    echo %s | openconnect --protocol=fortinet %s --cookie-on-stdin %s
+
+''' % (quote(cookie), cert_and_key, quote(endpoint.netloc)), file=stderr)
+
+    varvals = {
+        'HOST': quote(url.netloc),
+        'COOKIE': quote(cookie),
+    }
+    print('\n'.join('%s=%s' % pair for pair in varvals.items()))
+
+# Just print the result
+else:
+    if args.verbose:
+        print(res.headers, file=stderr)
+    print(res.text)