chrome/browser/safe_browsing/protocol_parser.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CHROME_BROWSER_SAFE_BROWSING_PROTOCOL_PARSER_H_
   6 #define CHROME_BROWSER_SAFE_BROWSING_PROTOCOL_PARSER_H_
   7
   8 // Parse the data returned from the chunk response.
   9 //
  10 // Based on the SafeBrowsing v2.1 protocol:
  11 // http://code.google.com/p/google-safe-browsing/wiki/Protocolv2Spec
  12 //
  13 // Read the response from a SafeBrowsing request, and parse into useful pieces.
  14 // The protocol is generally line oriented, but can contain binary data in the
  15 // actual chunk responses. The consumer of the protocol data should instantiate
  16 // the parser and call the appropriate parsing function on the data.
  17 //
  18 // Examples of protocol responses:
  19 //
  20 // 1. List identification
  21 //    i:goog-phish-shavar\n
  22 //    <command>:<command_data>\n
  23 //
  24 // 2. Minimum time to wait (seconds) until the next download request can be made
  25 //    n:1200\n
  26 //    <command>:<time_in_seconds>\n
  27 //
  28 // 3. Redirect URL for retrieving a chunk
  29 //    u:cache.googlevideo.com/safebrowsing/rd/goog-phish-shavar_a_1\n
  30 //    <command>:<url>\n
  31 //
  32 // 4. Add and sub chunks
  33 //   a:1:4:523\n...    <-- Add chunk + binary data
  34 //   s:13:4:17\n...    <-- Sub chunk + binary data
  35 //   <chunk_type>:<chunk_number>:<prefix_len>:<chunk_bytes>\n<binary_data>
  36 //
  37 // 5. Add-del and sub-del requests
  38 //    ad:1-4000,5001\n    <-- Add-del
  39 //    sd:1,3,5,7,903\n    <-- Sub-del
  40 //    <command>:<chunk_range>\n
  41
  42
  43 #include <string>
  44 #include <vector>
  45
  46 #include "base/basictypes.h"
  47 #include "chrome/browser/safe_browsing/chunk_range.h"
  48 #include "chrome/browser/safe_browsing/safe_browsing_util.h"
  49
  50
  51 class SafeBrowsingProtocolParser {
  52  public:
  53   SafeBrowsingProtocolParser();
  54
  55   // Parse the response of an update request. Results for chunk deletions (both
  56   // add-del and sub-del are returned in 'chunk_deletes', and new chunk URLs to
  57   // download are contained in 'chunk_urls'. The next time the client is allowed
  58   // to request another update is returned in 'next_update_sec'. 'reset' will
  59   // be set to true if the SafeBrowsing service wants us to dump our database.
  60   // Returns 'true'if it was able to decode the chunk properly, 'false' if not
  61   // decoded properly and the results should be ignored.
  62   bool ParseUpdate(const char* chunk_data,
  63                    int chunk_len,
  64                    int* next_update_sec,
  65                    bool* reset,
  66                    std::vector<SBChunkDelete>* chunk_deletes,
  67                    std::vector<ChunkUrl>* chunk_urls);
  68
  69   // Parse the response from a chunk URL request and returns the hosts/prefixes
  70   // for adds and subs in "chunks".  Returns 'true' on successful parsing,
  71   // 'false' otherwise. Any result should be ignored when a parse has failed.
  72   bool ParseChunk(const std::string& list_name,
  73                   const char* chunk_data,
  74                   int chunk_len,
  75                   SBChunkList* chunks);
  76
  77   // Parse the result of a GetHash request, returning the list of full hashes.
  78   bool ParseGetHash(const char* chunk_data,
  79                     int chunk_len,
  80                     std::vector<SBFullHashResult>* full_hashes);
  81
  82   // Convert a list of partial hashes into a proper GetHash request.
  83   void FormatGetHash(const std::vector<SBPrefix>& prefixes,
  84                      std::string* request);
  85
  86  private:
  87   bool ParseAddChunk(const std::string& list_name,
  88                      const char* data,
  89                      int data_len,
  90                      int hash_len,
  91                      std::deque<SBChunkHost>* hosts);
  92   bool ParseSubChunk(const std::string& list_name,
  93                      const char* data,
  94                      int data_len,
  95                      int hash_len,
  96                      std::deque<SBChunkHost>* hosts);
  97
  98   // Helper functions used by ParseAddChunk and ParseSubChunk.
  99   static bool ReadHostAndPrefixCount(const char** data,
 100                                      int* remaining,
 101                                      SBPrefix* host,
 102                                      int* count);
 103   static bool ReadChunkId(const char** data, int* remaining, int* chunk_id);
 104   static bool ReadPrefixes(
 105       const char** data, int* remaining, SBEntry* entry, int count);
 106
 107   // The name of the current list
 108   std::string list_name_;
 109
 110   DISALLOW_COPY_AND_ASSIGN(SafeBrowsingProtocolParser);
 111 };
 112
 113
 114 #endif  // CHROME_BROWSER_SAFE_BROWSING_PROTOCOL_PARSER_H_