src/HttpHdrContRange.cc

   1
   2 /*
   3  * $Id$
   4  *
   5  * DEBUG: section 68    HTTP Content-Range Header
   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 "Debug.h"
  38 #include "enums.h"
  39 #include "HttpHdrContRange.h"
  40 #include "HttpHeaderTools.h"
  41 #include "protos.h"
  42
  43 /*
  44  *    Currently only byte ranges are supported
  45  *
  46  *    Content-Range = "Content-Range" ":" content-range-spec
  47  *    content-range-spec      = byte-content-range-spec
  48  *    byte-content-range-spec = bytes-unit SP
  49  *                              ( byte-range-resp-spec | "*") "/"
  50  *                              ( entity-length | "*" )
  51  *    byte-range-resp-spec = first-byte-pos "-" last-byte-pos
  52  *    entity-length        = 1*DIGIT
  53  */
  54
  55
  56 /* local constants */
  57 #define range_spec_unknown (-1)
  58
  59 /* local routines */
  60 #define known_spec(s) ((s) != range_spec_unknown)
  61 #define size_min(a,b) ((a) <= (b) ? (a) : (b))
  62 #define size_diff(a,b) ((a) >= (b) ? ((a)-(b)) : 0)
  63
  64 /* globals */
  65
  66 /* parses range-resp-spec and inits spec, returns true on success */
  67 static int
  68 httpHdrRangeRespSpecParseInit(HttpHdrRangeSpec * spec, const char *field, int flen)
  69 {
  70     const char *p;
  71     assert(spec);
  72     spec->offset = spec->length = range_spec_unknown;
  73
  74     if (flen < 2)
  75         return 0;
  76
  77     /* is spec given ? */
  78     if (*field == '*')
  79         return 1;
  80
  81     /* check format, must be %d-%d */
  82     if (!((p = strchr(field, '-')) && (p - field < flen))) {
  83         debugs(68, 2, "invalid (no '-') resp-range-spec near: '" << field << "'");
  84         return 0;
  85     }
  86
  87     /* parse offset */
  88     if (!httpHeaderParseOffset(field, &spec->offset))
  89         return 0;
  90
  91     /* Additional check for BUG2155 - there MUST BE first-byte-pos and it MUST be positive*/
  92     if (spec->offset < 0) {
  93         debugs(68, 2, "invalid (no first-byte-pos or it is negative) resp-range-spec near: '" << field << "'");
  94         return 0;
  95     }
  96
  97     ++p;
  98
  99     /* do we have last-pos ? */
 100     if (p - field >= flen) {
 101         debugs(68, 2, "invalid (no last-byte-pos) resp-range-spec near: '" << field << "'");
 102         return 0;
 103     }
 104
 105     int64_t last_pos;
 106
 107     if (!httpHeaderParseOffset(p, &last_pos))
 108         return 0;
 109
 110     if (last_pos < spec->offset) {
 111         debugs(68, 2, "invalid (negative last-byte-pos) resp-range-spec near: '" << field << "'");
 112         return 0;
 113     }
 114
 115     spec->length = size_diff(last_pos + 1, spec->offset);
 116
 117     /* we managed to parse, check if the result makes sence */
 118     if (spec->length <= 0) {
 119         debugs(68, 2, "invalid range (" << spec->offset << " += " <<
 120                (long int) spec->length << ") in resp-range-spec near: '" << field << "'");
 121         return 0;
 122     }
 123
 124     return 1;
 125 }
 126
 127 static void
 128 httpHdrRangeRespSpecPackInto(const HttpHdrRangeSpec * spec, Packer * p)
 129 {
 130     /* Ensure typecast is safe */
 131     assert (spec->length >= 0);
 132
 133     if (!known_spec(spec->offset) || !known_spec(spec->length))
 134         packerPrintf(p, "*");
 135     else
 136         packerPrintf(p, "bytes %" PRId64 "-%" PRId64,
 137                      spec->offset, spec->offset + spec->length - 1);
 138 }
 139
 140 /*
 141  * Content Range
 142  */
 143
 144 HttpHdrContRange *
 145 httpHdrContRangeCreate(void)
 146 {
 147     HttpHdrContRange *r = (HttpHdrContRange *)memAllocate(MEM_HTTP_HDR_CONTENT_RANGE);
 148     r->spec.offset = r->spec.length = range_spec_unknown;
 149     r->elength = range_spec_unknown;
 150     return r;
 151 }
 152
 153 HttpHdrContRange *
 154 httpHdrContRangeParseCreate(const char *str)
 155 {
 156     HttpHdrContRange *r = httpHdrContRangeCreate();
 157
 158     if (!httpHdrContRangeParseInit(r, str)) {
 159         httpHdrContRangeDestroy(r);
 160         r = NULL;
 161     }
 162
 163     return r;
 164 }
 165
 166 /* returns true if ranges are valid; inits HttpHdrContRange */
 167 int
 168 httpHdrContRangeParseInit(HttpHdrContRange * range, const char *str)
 169 {
 170     const char *p;
 171     assert(range && str);
 172     debugs(68, 8, "parsing content-range field: '" << str << "'");
 173     /* check range type */
 174
 175     if (strncasecmp(str, "bytes ", 6))
 176         return 0;
 177
 178     str += 6;
 179
 180     /* split */
 181     if (!(p = strchr(str, '/')))
 182         return 0;
 183
 184     if (*str == '*')
 185         range->spec.offset = range->spec.length = range_spec_unknown;
 186     else if (!httpHdrRangeRespSpecParseInit(&range->spec, str, p - str))
 187         return 0;
 188
 189     ++p;
 190
 191     if (*p == '*')
 192         range->elength = range_spec_unknown;
 193     else if (!httpHeaderParseOffset(p, &range->elength))
 194         return 0;
 195     else if (range->elength <= 0) {
 196         /* Additional paranoidal check for BUG2155 - entity-length MUST be > 0 */
 197         debugs(68, 2, "invalid (entity-length is negative) content-range-spec near: '" << str << "'");
 198         return 0;
 199     } else if (known_spec(range->spec.length) && range->elength < (range->spec.offset + range->spec.length)) {
 200         debugs(68, 2, "invalid (range is outside entity-length) content-range-spec near: '" << str << "'");
 201         return 0;
 202     }
 203
 204     debugs(68, 8, "parsed content-range field: " <<
 205            (long int) range->spec.offset << "-" <<
 206            (long int) range->spec.offset + range->spec.length - 1 << " / " <<
 207            (long int) range->elength);
 208
 209     return 1;
 210 }
 211
 212 void
 213 httpHdrContRangeDestroy(HttpHdrContRange * range)
 214 {
 215     assert(range);
 216     memFree(range, MEM_HTTP_HDR_CONTENT_RANGE);
 217 }
 218
 219 HttpHdrContRange *
 220 httpHdrContRangeDup(const HttpHdrContRange * range)
 221 {
 222     HttpHdrContRange *dup;
 223     assert(range);
 224     dup = httpHdrContRangeCreate();
 225     *dup = *range;
 226     return dup;
 227 }
 228
 229 void
 230 httpHdrContRangePackInto(const HttpHdrContRange * range, Packer * p)
 231 {
 232     assert(range && p);
 233     httpHdrRangeRespSpecPackInto(&range->spec, p);
 234     /* Ensure typecast is safe */
 235     assert (range->elength >= 0);
 236
 237     if (!known_spec(range->elength))
 238         packerPrintf(p, "/*");
 239     else
 240         packerPrintf(p, "/%" PRId64, range->elength);
 241 }
 242
 243 void
 244 httpHdrContRangeSet(HttpHdrContRange * cr, HttpHdrRangeSpec spec, int64_t ent_len)
 245 {
 246     assert(cr && ent_len >= 0);
 247     cr->spec = spec;
 248     cr->elength = ent_len;
 249 }