src/HttpMsg.cc

   1
   2 /*
   3  * $Id$
   4  *
   5  * DEBUG: section 74    HTTP Message
   6  * AUTHOR: Alex Rousskov
   7  *
   8  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   9  * ----------------------------------------------------------
  10  *
  11  *  Squid is the result of efforts by numerous individuals from
  12  *  the Internet community; see the CONTRIBUTORS file for full
  13  *  details.   Many organizations have provided support for Squid's
  14  *  development; see the SPONSORS file for full details.  Squid is
  15  *  Copyrighted (C) 2001 by the Regents of the University of
  16  *  California; see the COPYRIGHT file for full details.  Squid
  17  *  incorporates software developed and/or copyrighted by other
  18  *  sources; see the CREDITS file for full details.
  19  *
  20  *  This program is free software; you can redistribute it and/or modify
  21  *  it under the terms of the GNU General Public License as published by
  22  *  the Free Software Foundation; either version 2 of the License, or
  23  *  (at your option) any later version.
  24  *
  25  *  This program is distributed in the hope that it will be useful,
  26  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  27  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  28  *  GNU General Public License for more details.
  29  *
  30  *  You should have received a copy of the GNU General Public License
  31  *  along with this program; if not, write to the Free Software
  32  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  33  *
  34  */
  35
  36 #include "squid.h"
  37 #include "HttpMsg.h"
  38 #include "MemBuf.h"
  39
  40 HttpMsg::HttpMsg(http_hdr_owner_type owner): header(owner),
  41         cache_control(NULL), hdr_sz(0), content_length(0), protocol(AnyP::PROTO_NONE),
  42         pstate(psReadyToParseStartLine), lock_count(0)
  43 {}
  44
  45 HttpMsg::~HttpMsg()
  46 {
  47     assert(lock_count == 0);
  48     assert(!body_pipe);
  49 }
  50
  51 HttpMsgParseState &operator++ (HttpMsgParseState &aState)
  52 {
  53     int tmp = (int)aState;
  54     aState = (HttpMsgParseState)(++tmp);
  55     return aState;
  56 }
  57
  58 /* find end of headers */
  59 int
  60 httpMsgIsolateHeaders(const char **parse_start, int l, const char **blk_start, const char **blk_end)
  61 {
  62     /*
  63      * parse_start points to the first line of HTTP message *headers*,
  64      * not including the request or status lines
  65      */
  66     size_t end = headersEnd(*parse_start, l);
  67     int nnl;
  68
  69     if (end) {
  70         *blk_start = *parse_start;
  71         *blk_end = *parse_start + end - 1;
  72         /*
  73          * leave blk_end pointing to the first character after the
  74          * first newline which terminates the headers
  75          */
  76         assert(**blk_end == '\n');
  77
  78         while (*(*blk_end - 1) == '\r')
  79             (*blk_end)--;
  80
  81         assert(*(*blk_end - 1) == '\n');
  82
  83         *parse_start += end;
  84
  85         return 1;
  86     }
  87
  88     /*
  89      * If we didn't find the end of headers, and parse_start does
  90      * NOT point to a CR or NL character, then return failure
  91      */
  92     if (**parse_start != '\r' && **parse_start != '\n')
  93         return 0;               /* failure */
  94
  95     /*
  96      * If we didn't find the end of headers, and parse_start does point
  97      * to an empty line, then we have empty headers.  Skip all CR and
  98      * NL characters up to the first NL.  Leave parse_start pointing at
  99      * the first character after the first NL.
 100      */
 101     *blk_start = *parse_start;
 102
 103     *blk_end = *blk_start;
 104
 105     for (nnl = 0; nnl == 0; (*parse_start)++) {
 106         if (**parse_start == '\r')
 107             (void) 0;
 108         else if (**parse_start == '\n')
 109             nnl++;
 110         else
 111             break;
 112     }
 113
 114     return 1;
 115 }
 116
 117 /* find first CRLF */
 118 static int
 119 httpMsgIsolateStart(const char **parse_start, const char **blk_start, const char **blk_end)
 120 {
 121     int slen = strcspn(*parse_start, "\r\n");
 122
 123     if (!(*parse_start)[slen])  /* no CRLF found */
 124         return 0;
 125
 126     *blk_start = *parse_start;
 127
 128     *blk_end = *blk_start + slen;
 129
 130     while (**blk_end == '\r')   /* CR */
 131         (*blk_end)++;
 132
 133     if (**blk_end == '\n')      /* LF */
 134         (*blk_end)++;
 135
 136     *parse_start = *blk_end;
 137
 138     return 1;
 139 }
 140
 141 // negative return is the negated HTTP_ error code
 142 // zero return means need more data
 143 // positive return is the size of parsed headers
 144 bool HttpMsg::parse(MemBuf *buf, bool eof, http_status *error)
 145 {
 146     assert(error);
 147     *error = HTTP_STATUS_NONE;
 148
 149     // httpMsgParseStep() and debugging require 0-termination, unfortunately
 150     buf->terminate(); // does not affect content size
 151
 152     // find the end of headers
 153     const size_t hdr_len = headersEnd(buf->content(), buf->contentSize());
 154
 155     // sanity check the start line to see if this is in fact an HTTP message
 156     if (!sanityCheckStartLine(buf, hdr_len, error)) {
 157         // NP: sanityCheck sets *error and sends debug warnings on syntax errors.
 158         // if we have seen the connection close, this is an error too
 159         if (eof && *error==HTTP_STATUS_NONE)
 160             *error = HTTP_INVALID_HEADER;
 161
 162         return false;
 163     }
 164
 165     // TODO: move to httpReplyParseStep()
 166     if (hdr_len > Config.maxReplyHeaderSize || (hdr_len <= 0 && (size_t)buf->contentSize() > Config.maxReplyHeaderSize)) {
 167         debugs(58, 1, "HttpMsg::parse: Too large reply header (" << hdr_len << " > " << Config.maxReplyHeaderSize);
 168         *error = HTTP_HEADER_TOO_LARGE;
 169         return false;
 170     }
 171
 172     if (hdr_len <= 0) {
 173         debugs(58, 3, "HttpMsg::parse: failed to find end of headers (eof: " << eof << ") in '" << buf->content() << "'");
 174
 175         if (eof) // iff we have seen the end, this is an error
 176             *error = HTTP_INVALID_HEADER;
 177
 178         return false;
 179     }
 180
 181     const int res = httpMsgParseStep(buf->content(), buf->contentSize(), eof);
 182
 183     if (res < 0) { // error
 184         debugs(58, 3, "HttpMsg::parse: cannot parse isolated headers in '" << buf->content() << "'");
 185         *error = HTTP_INVALID_HEADER;
 186         return false;
 187     }
 188
 189     if (res == 0) {
 190         debugs(58, 2, "HttpMsg::parse: strange, need more data near '" << buf->content() << "'");
 191         *error = HTTP_INVALID_HEADER;
 192         return false; // but this should not happen due to headersEnd() above
 193     }
 194
 195     assert(res > 0);
 196     debugs(58, 9, "HttpMsg::parse success (" << hdr_len << " bytes) near '" << buf->content() << "'");
 197
 198     if (hdr_sz != (int)hdr_len) {
 199         debugs(58, 1, "internal HttpMsg::parse vs. headersEnd error: " <<
 200                hdr_sz << " != " << hdr_len);
 201         hdr_sz = (int)hdr_len; // because old http.cc code used hdr_len
 202     }
 203
 204     return true;
 205 }
 206
 207 /*
 208  * parseCharBuf() takes character buffer of HTTP headers (buf),
 209  * which may not be NULL-terminated, and fills in an HttpMsg
 210  * structure.  The parameter 'end' specifies the offset to
 211  * the end of the reply headers.  The caller may know where the
 212  * end is, but is unable to NULL-terminate the buffer.  This function
 213  * returns true on success.
 214  */
 215 bool
 216 HttpMsg::parseCharBuf(const char *buf, ssize_t end)
 217 {
 218     MemBuf mb;
 219     int success;
 220     /* reset current state, because we are not used in incremental fashion */
 221     reset();
 222     mb.init();
 223     mb.append(buf, end);
 224     mb.terminate();
 225     success = httpMsgParseStep(mb.buf, mb.size, 0);
 226     mb.clean();
 227     return success == 1;
 228 }
 229
 230 /*
 231  * parses a 0-terminating buffer into HttpMsg.
 232  * Returns:
 233  *      1 -- success
 234  *       0 -- need more data (partial parse)
 235  *      -1 -- parse error
 236  */
 237 int
 238 HttpMsg::httpMsgParseStep(const char *buf, int len, int atEnd)
 239 {
 240     const char *parse_start = buf;
 241     int parse_len = len;
 242     const char *blk_start, *blk_end;
 243     const char **parse_end_ptr = &blk_end;
 244     assert(parse_start);
 245     assert(pstate < psParsed);
 246
 247     *parse_end_ptr = parse_start;
 248
 249     PROF_start(HttpMsg_httpMsgParseStep);
 250
 251     if (pstate == psReadyToParseStartLine) {
 252         if (!httpMsgIsolateStart(&parse_start, &blk_start, &blk_end)) {
 253             PROF_stop(HttpMsg_httpMsgParseStep);
 254             return 0;
 255         }
 256
 257         if (!parseFirstLine(blk_start, blk_end)) {
 258             PROF_stop(HttpMsg_httpMsgParseStep);
 259             return httpMsgParseError();
 260         }
 261
 262         *parse_end_ptr = parse_start;
 263
 264         hdr_sz = *parse_end_ptr - buf;
 265         parse_len = parse_len - hdr_sz;
 266
 267         ++pstate;
 268     }
 269
 270     /*
 271      * XXX This code uses parse_start; but if we're incrementally parsing then
 272      * this code might not actually be given parse_start at the right spot (just
 273      * after headers.) Grr.
 274      */
 275     if (pstate == psReadyToParseHeaders) {
 276         if (!httpMsgIsolateHeaders(&parse_start, parse_len, &blk_start, &blk_end)) {
 277             if (atEnd) {
 278                 blk_start = parse_start, blk_end = blk_start + strlen(blk_start);
 279             } else {
 280                 PROF_stop(HttpMsg_httpMsgParseStep);
 281                 return 0;
 282             }
 283         }
 284
 285         if (!header.parse(blk_start, blk_end)) {
 286             PROF_stop(HttpMsg_httpMsgParseStep);
 287             return httpMsgParseError();
 288         }
 289
 290         hdrCacheInit();
 291
 292         *parse_end_ptr = parse_start;
 293
 294         hdr_sz = *parse_end_ptr - buf;
 295
 296         ++pstate;
 297     }
 298
 299     PROF_stop(HttpMsg_httpMsgParseStep);
 300     return 1;
 301 }
 302
 303 /* handy: resets and returns -1 */
 304 int
 305 HttpMsg::httpMsgParseError()
 306 {
 307     reset();
 308     return -1;
 309 }
 310
 311 void
 312 HttpMsg::setContentLength(int64_t clen)
 313 {
 314     header.delById(HDR_CONTENT_LENGTH); // if any
 315     header.putInt64(HDR_CONTENT_LENGTH, clen);
 316     content_length = clen;
 317 }
 318
 319 bool
 320 HttpMsg::persistent() const
 321 {
 322     if (http_ver > HttpVersion(1, 0)) {
 323         /*
 324          * for modern versions of HTTP: persistent unless there is
 325          * a "Connection: close" header.
 326          */
 327         return !httpHeaderHasConnDir(&header, "close");
 328     } else {
 329         /* for old versions of HTTP: persistent if has "keep-alive" */
 330         return httpHeaderHasConnDir(&header, "keep-alive");
 331     }
 332 }
 333
 334 void HttpMsg::packInto(Packer *p, bool full_uri) const
 335 {
 336     packFirstLineInto(p, full_uri);
 337     header.packInto(p);
 338     packerAppend(p, "\r\n", 2);
 339 }
 340
 341 void HttpMsg::hdrCacheInit()
 342 {
 343     content_length = header.getInt64(HDR_CONTENT_LENGTH);
 344     assert(NULL == cache_control);
 345     cache_control = header.getCc();
 346 }
 347
 348 /*
 349  * useful for debugging
 350  */
 351 void HttpMsg::firstLineBuf(MemBuf& mb)
 352 {
 353     Packer p;
 354     packerToMemInit(&p, &mb);
 355     packFirstLineInto(&p, true);
 356     packerClean(&p);
 357 }
 358
 359 // use HTTPMSGLOCK() instead of calling this directly
 360 HttpMsg *
 361 HttpMsg::_lock()
 362 {
 363     lock_count++;
 364     return this;
 365 }
 366
 367 // use HTTPMSGUNLOCK() instead of calling this directly
 368 void
 369 HttpMsg::_unlock()
 370 {
 371     assert(lock_count > 0);
 372     --lock_count;
 373
 374     if (0 == lock_count)
 375         delete this;
 376 }