src/http/one/Parser.h

   1 /*
   2  * Copyright (C) 1996-2017 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #ifndef _SQUID_SRC_HTTP_ONE_PARSER_H
  10 #define _SQUID_SRC_HTTP_ONE_PARSER_H
  11
  12 #include "anyp/ProtocolVersion.h"
  13 #include "http/one/forward.h"
  14 #include "http/StatusCode.h"
  15 #include "sbuf/SBuf.h"
  16
  17 namespace Http {
  18 namespace One {
  19
  20 // Parser states
  21 enum ParseState {
  22     HTTP_PARSE_NONE,      ///< initialized, but nothing usefully parsed yet
  23     HTTP_PARSE_FIRST,     ///< HTTP/1 message first-line
  24     HTTP_PARSE_CHUNK_SZ,  ///< HTTP/1.1 chunked encoding chunk-size
  25     HTTP_PARSE_CHUNK_EXT, ///< HTTP/1.1 chunked encoding chunk-ext
  26     HTTP_PARSE_CHUNK,     ///< HTTP/1.1 chunked encoding chunk-data
  27     HTTP_PARSE_MIME,      ///< HTTP/1 mime-header block
  28     HTTP_PARSE_DONE       ///< parsed a message header, or reached a terminal syntax error
  29 };
  30
  31 /** HTTP/1.x protocol parser
  32  *
  33  * Works on a raw character I/O buffer and tokenizes the content into
  34  * the major CRLF delimited segments of an HTTP/1 procotol message:
  35  *
  36  * \item first-line (request-line / simple-request / status-line)
  37  * \item mime-header 0*( header-name ':' SP field-value CRLF)
  38  */
  39 class Parser : public RefCountable
  40 {
  41 public:
  42     typedef SBuf::size_type size_type;
  43
  44     Parser() : parseStatusCode(Http::scNone), parsingStage_(HTTP_PARSE_NONE), hackExpectsMime_(false) {}
  45     virtual ~Parser() {}
  46
  47     /// Set this parser back to a default state.
  48     /// Will DROP any reference to a buffer (does not free).
  49     virtual void clear() = 0;
  50
  51     /// attempt to parse a message from the buffer
  52     /// \retval true if a full message was found and parsed
  53     /// \retval false if incomplete, invalid or no message was found
  54     virtual bool parse(const SBuf &aBuf) = 0;
  55
  56     /** Whether the parser is waiting on more data to complete parsing a message.
  57      * Use to distinguish between incomplete data and error results
  58      * when parse() returns false.
  59      */
  60     bool needsMoreData() const {return parsingStage_!=HTTP_PARSE_DONE;}
  61
  62     /// size in bytes of the first line including CRLF terminator
  63     virtual size_type firstLineSize() const = 0;
  64
  65     /// size in bytes of the message headers including CRLF terminator(s)
  66     /// but excluding first-line bytes
  67     size_type headerBlockSize() const {return mimeHeaderBlock_.length();}
  68
  69     /// size in bytes of HTTP message block, includes first-line and mime headers
  70     /// excludes any body/entity/payload bytes
  71     /// excludes any garbage prefix before the first-line
  72     size_type messageHeaderSize() const {return firstLineSize() + headerBlockSize();}
  73
  74     /// buffer containing HTTP mime headers, excluding message first-line.
  75     SBuf mimeHeader() const {return mimeHeaderBlock_;}
  76
  77     /// the protocol label for this message
  78     const AnyP::ProtocolVersion & messageProtocol() const {return msgProtocol_;}
  79
  80     /**
  81      * Scan the mime header block (badly) for a header with the given name.
  82      *
  83      * BUG: omits lines when searching for headers with obs-fold or multiple entries.
  84      *
  85      * BUG: limits output to just 1KB when Squid accepts up to 64KB line length.
  86      *
  87      * \return A pointer to a field-value of the first matching field-name, or NULL.
  88      */
  89     char *getHeaderField(const char *name);
  90
  91     /// the remaining unprocessed section of buffer
  92     const SBuf &remaining() const {return buf_;}
  93
  94 #if USE_HTTP_VIOLATIONS
  95     /// the right debugs() level for parsing HTTP violation messages
  96     int violationLevel() const;
  97 #endif
  98
  99     /**
 100      * HTTP status code resulting from the parse process.
 101      * to be used on the invalid message handling.
 102      *
 103      * Http::scNone indicates incomplete parse,
 104      * Http::scOkay indicates no error,
 105      * other codes represent a parse error.
 106      */
 107     Http::StatusCode parseStatusCode;
 108
 109     /// the characters which are to be considered valid whitespace
 110     /// (WSP / BSP / OWS)
 111     static const CharacterSet &DelimiterCharacters();
 112
 113 protected:
 114     /**
 115      * detect and skip the CRLF or (if tolerant) LF line terminator
 116      * consume from the tokenizer.
 117      *
 118      * throws if non-terminator is detected.
 119      * \retval true only if line terminator found.
 120      * \retval false incomplete or missing line terminator, need more data.
 121      */
 122     bool skipLineTerminator(Http1::Tokenizer &tok) const;
 123
 124     /**
 125      * Scan to find the mime headers block for current message.
 126      *
 127      * \retval true   If mime block (or a blocks non-existence) has been
 128      *                identified accurately within limit characters.
 129      *                mimeHeaderBlock_ has been updated and buf_ consumed.
 130      *
 131      * \retval false  An error occured, or no mime terminator found within limit.
 132      */
 133     bool grabMimeBlock(const char *which, const size_t limit);
 134
 135     /// RFC 7230 section 2.6 - 7 magic octets
 136     static const SBuf Http1magic;
 137
 138     /// bytes remaining to be parsed
 139     SBuf buf_;
 140
 141     /// what stage the parser is currently up to
 142     ParseState parsingStage_;
 143
 144     /// what protocol label has been found in the first line (if any)
 145     AnyP::ProtocolVersion msgProtocol_;
 146
 147     /// buffer holding the mime headers (if any)
 148     SBuf mimeHeaderBlock_;
 149
 150     /// Whether the invalid HTTP as HTTP/0.9 hack expects a mime header block
 151     bool hackExpectsMime_;
 152
 153 private:
 154     void cleanMimePrefix();
 155     void unfoldMime();
 156 };
 157
 158 } // namespace One
 159 } // namespace Http
 160
 161 #endif /*  _SQUID_SRC_HTTP_ONE_PARSER_H */
 162