Add HTTP requests example

examples/http_requests.cpp

@@ -0,0 +1,145 @@
+/*
+ * Copyright (c) 2016, Matias Fontanini
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following disclaimer
+ *   in the documentation and/or other materials provided with the
+ *   distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <string>
+#include <iostream>
+#include <stdexcept>
+#include <boost/regex.hpp>
+#include "tins/tcp_ip/stream_follower.h"
+#include "tins/sniffer.h"
+
+using std::string;
+using std::cout;
+using std::cerr;
+using std::endl;
+using std::exception;
+
+using boost::regex;
+using boost::match_results;
+
+using Tins::Packet;
+using Tins::Sniffer;
+using Tins::SnifferConfiguration;
+using Tins::TCPIP::Stream;
+using Tins::TCPIP::StreamFollower;
+
+// This example captures and follows TCP streams seen on port 80. It will
+// wait until both the client and server send data and then apply a regex
+// to both payloads, extrating some information and printing it.
+
+// Don't buffer more than 3kb of data in either request/response
+const size_t MAX_PAYLOAD = 3 * 1024;
+// The regex to be applied on the request. This will extract the HTTP
+// method being used, the request's path and the Host header value.
+regex request_regex("([\\w]+) ([^ ]+).+\r\nHost: ([\\d\\w\\.-]+)\r\n");
+// The regex to be applied on the response. This finds the response code.
+regex response_regex("HTTP/[^ ]+ ([\\d]+)");
+
+void on_server_data(Stream& stream) {
+    match_results<Stream::payload_type::const_iterator> client_match;
+    match_results<Stream::payload_type::const_iterator> server_match;
+    const Stream::payload_type& client_payload = stream.client_payload();
+    const Stream::payload_type& server_payload = stream.server_payload();
+    // Run the regexes on client/server payloads
+    bool valid = regex_search(server_payload.begin(), server_payload.end(),
+                              server_match, response_regex) &&
+                 regex_search(client_payload.begin(), client_payload.end(),
+                              client_match, request_regex);
+    // If we matched both the client and the server regexes
+    if (valid) {
+        // Extract all fields
+        string method = string(client_match[1].first, client_match[1].second);
+        string url = string(client_match[2].first, client_match[2].second);
+        string host = string(client_match[3].first, client_match[3].second);
+        string response_code = string(server_match[1].first, server_match[1].second);
+        // Now print them
+        cout << method << " http://" << host << url << " -> " << response_code << endl;
+
+        // Once we've seen the first request on this stream, ignore it
+        stream.ignore_client_data();
+        stream.ignore_server_data();
+    }
+    
+    // Just in case the server returns invalid data, stop at 3kb
+    if (stream.server_payload().size() > MAX_PAYLOAD) {
+        stream.ignore_server_data();
+    }
+}
+
+void on_client_data(Stream& stream) {
+    // Don't hold more than 3kb of data from the client's flow
+    if (stream.client_payload().size() > MAX_PAYLOAD) {
+        stream.ignore_client_data();
+    }
+}
+
+void on_new_connection(Stream& stream) {
+    stream.client_data_callback(&on_client_data);
+    stream.server_data_callback(&on_server_data);
+    // Don't automatically cleanup the stream's data, as we'll manage
+    // the buffer ourselves and let it grow until we see a full request
+    // and response
+    stream.auto_cleanup_payloads(false);
+}
+
+int main(int argc, char* argv[]) {
+    if (argc != 2) {
+        cout << "Usage: " << argv[0] << " <interface>" << endl;
+        return 1;
+    }
+
+    try {
+        // Construct the sniffer configuration object
+        SnifferConfiguration config;
+        // Only capture TCP traffic sent from/to port 80
+        config.set_filter("tcp port 80");
+        // Construct the sniffer we'll use
+        Sniffer sniffer(argv[1], config);
+
+        cout << "Starting capture on interface " << argv[1] << endl;
+
+        // Now construct the stream follower
+        StreamFollower follower;
+        // We just need to specify the callback to be executed when a new 
+        // stream is captured. In this stream, you should define which callbacks
+        // will be executed whenever new data is sent on that stream 
+        // (see on_new_connection)
+        follower.new_stream_callback(&on_new_connection);
+        // Now start capturing. Every time there's a new packet, call 
+        // follower.process_packet
+        sniffer.sniff_loop([&](Packet& packet) {
+            follower.process_packet(packet);
+            return true;
+        });
+    }
+    catch (exception& ex) {
+        cerr << "Error: " << ex.what() << endl;
+        return 1;
+    }
+}