Agent: Refactor HTTPFinger to conform to IFingerprinter interface

* Remove dependency on Plugin, HostFinger, and WormConfiguration
* Improve readability
* Reduce unnecessary HTTP requests by using the PortScanData to only
  query ports we know are open.

monkey/infection_monkey/network/httpfinger.py

@@ -1,47 +1,80 @@
 import logging
+from contextlib import closing
+from typing import Dict, Iterable, Optional, Set, Tuple
 
-import infection_monkey.config
-from infection_monkey.network.HostFinger import HostFinger
+from requests import head
+from requests.exceptions import ConnectionError, Timeout
+
+from infection_monkey.i_puppet import (
+    FingerprintData,
+    IFingerprinter,
+    PingScanData,
+    PortScanData,
+    PortStatus,
+)
 
 logger = logging.getLogger(__name__)
 
 
-class HTTPFinger(HostFinger):
+class HTTPFinger(IFingerprinter):
     """
     Goal is to recognise HTTP servers, where what we currently care about is apache.
     """
 
-    _SCANNED_SERVICE = "HTTP"
+    def get_host_fingerprint(
+        self,
+        host: str,
+        ping_scan_data: PingScanData,
+        port_scan_data: Dict[int, PortScanData],
+        options: Dict,
+    ):
+        services = {}
+        http_ports = set(options.get("http_ports", []))
+        ports_to_fingerprint = _get_open_http_ports(http_ports, port_scan_data)
 
-    def __init__(self):
-        self._config = infection_monkey.config.WormConfiguration
-        self.HTTP = [(port, str(port)) for port in self._config.HTTP_PORTS]
+        for port in ports_to_fingerprint:
+            server_header_contents, ssl = _query_potential_http_server(host, port)
 
-    def get_host_fingerprint(self, host):
-        from contextlib import closing
+            if server_header_contents is not None:
+                services[f"tcp-{port}"] = {
+                    "display_name": "HTTP",
+                    "port": port,
+                    "name": "http",
+                    "data": (server_header_contents, ssl),
+                }
 
-        from requests import head
-        from requests.exceptions import ConnectionError, Timeout
+        return FingerprintData(None, None, services)
 
-        for port in self.HTTP:
-            # check both http and https
-            http = "http://" + host.ip_addr + ":" + port[1]
-            https = "https://" + host.ip_addr + ":" + port[1]
 
-            # try http, we don't optimise for 443
-            for url in (https, http):  # start with https and downgrade
-                try:
-                    with closing(head(url, verify=False, timeout=1)) as req:  # noqa: DUO123
-                        server = req.headers.get("Server")
-                        ssl = True if "https://" in url else False
-                        self.init_service(host.services, ("tcp-" + port[1]), port[0])
-                        host.services["tcp-" + port[1]]["name"] = "http"
-                        host.services["tcp-" + port[1]]["data"] = (server, ssl)
-                        logger.info("Port %d is open on host %s " % (port[0], host))
-                        break  # https will be the same on the same port
-                except Timeout:
-                    logger.debug(f"Timeout while requesting headers from {url}")
-                except ConnectionError:  # Someone doesn't like us
-                    logger.debug(f"Connection error while requesting headers from {url}")
+def _query_potential_http_server(host: str, port: int) -> Tuple[Optional[str], Optional[bool]]:
+    # check both http and https
+    http = f"http://{host}:{port}"
+    https = f"https://{host}:{port}"
 
-        return True
+    # try http, we don't optimise for 443
+    for url, ssl in ((https, True), (http, False)):  # start with https and downgrade
+        server_header_contents = _get_server_from_headers(url)
+
+        if server_header_contents is not None:
+            return (server_header_contents, ssl)
+
+    return (None, None)
+
+
+def _get_server_from_headers(url: str) -> Optional[str]:
+    try:
+        with closing(head(url, verify=False, timeout=1)) as req:  # noqa: DUO123
+            return req.headers.get("Server")
+    except Timeout:
+        logger.debug(f"Timeout while requesting headers from {url}")
+    except ConnectionError:  # Someone doesn't like us
+        logger.debug(f"Connection error while requesting headers from {url}")
+
+    return None
+
+
+def _get_open_http_ports(
+    allowed_http_ports: Set, port_scan_data: Dict[int, PortScanData]
+) -> Iterable[int]:
+    open_ports = (psd.port for psd in port_scan_data.values() if psd.status == PortStatus.Open)
+    return (port for port in open_ports if port in allowed_http_ports)