// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CHROME_BROWSER_SAFE_BROWSING_PROTOCOL_PARSER_H_
#define CHROME_BROWSER_SAFE_BROWSING_PROTOCOL_PARSER_H_
// Parse the data returned from the chunk response.
//
// Based on the SafeBrowsing v2.1 protocol:
// http://code.google.com/p/google-safe-browsing/wiki/Protocolv2Spec
//
// Read the response from a SafeBrowsing request, and parse into useful pieces.
// The protocol is generally line oriented, but can contain binary data in the
// actual chunk responses. The consumer of the protocol data should instantiate
// the parser and call the appropriate parsing function on the data.
//
// Examples of protocol responses:
//
// 1. List identification
// i:goog-phish-shavar\n
// <command>:<command_data>\n
//
// 2. Minimum time to wait (seconds) until the next download request can be made
// n:1200\n
// <command>:<time_in_seconds>\n
//
// 3. Redirect URL for retrieving a chunk
// u:cache.googlevideo.com/safebrowsing/rd/goog-phish-shavar_a_1\n
// <command>:<url>\n
//
// 4. Add and sub chunks
// a:1:4:523\n... <-- Add chunk + binary data
// s:13:4:17\n... <-- Sub chunk + binary data
// <chunk_type>:<chunk_number>:<prefix_len>:<chunk_bytes>\n<binary_data>
//
// 5. Add-del and sub-del requests
// ad:1-4000,5001\n <-- Add-del
// sd:1,3,5,7,903\n <-- Sub-del
// <command>:<chunk_range>\n
#include <string>
#include <vector>
#include "base/basictypes.h"
#include "chrome/browser/safe_browsing/chunk_range.h"
#include "chrome/browser/safe_browsing/safe_browsing_util.h"
class SafeBrowsingProtocolParser {
public:
SafeBrowsingProtocolParser();
// Parse the response of an update request. Results for chunk deletions (both
// add-del and sub-del are returned in 'chunk_deletes', and new chunk URLs to
// download are contained in 'chunk_urls'. The next time the client is allowed
// to request another update is returned in 'next_update_sec'. 'reset' will
// be set to true if the SafeBrowsing service wants us to dump our database.
// Returns 'true'if it was able to decode the chunk properly, 'false' if not
// decoded properly and the results should be ignored.
bool ParseUpdate(const char* chunk_data,
int chunk_len,
int* next_update_sec,
bool* reset,
std::vector<SBChunkDelete>* chunk_deletes,
std::vector<ChunkUrl>* chunk_urls);
// Parse the response from a chunk URL request and returns the hosts/prefixes
// for adds and subs in "chunks". Returns 'true' on successful parsing,
// 'false' otherwise. Any result should be ignored when a parse has failed.
bool ParseChunk(const std::string& list_name,
const char* chunk_data,
int chunk_len,
SBChunkList* chunks);
// Parse the result of a GetHash request, returning the list of full hashes.
bool ParseGetHash(const char* chunk_data,
int chunk_len,
std::vector<SBFullHashResult>* full_hashes);
// Convert a list of partial hashes into a proper GetHash request.
void FormatGetHash(const std::vector<SBPrefix>& prefixes,
std::string* request);
private:
bool ParseAddChunk(const std::string& list_name,
const char* data,
int data_len,
int hash_len,
std::deque<SBChunkHost>* hosts);
bool ParseSubChunk(const std::string& list_name,
const char* data,
int data_len,
int hash_len,
std::deque<SBChunkHost>* hosts);
// Helper functions used by ParseAddChunk and ParseSubChunk.
static bool ReadHostAndPrefixCount(const char** data,
int* remaining,
SBPrefix* host,
int* count);
static bool ReadChunkId(const char** data, int* remaining, int* chunk_id);
static bool ReadPrefixes(
const char** data, int* remaining, SBEntry* entry, int count);
// The name of the current list
std::string list_name_;
DISALLOW_COPY_AND_ASSIGN(SafeBrowsingProtocolParser);
};
#endif // CHROME_BROWSER_SAFE_BROWSING_PROTOCOL_PARSER_H_