src/HttpHdrContRange.cc

   1
   2 /*
   3  * DEBUG: section 68    HTTP Content-Range Header
   4  * AUTHOR: Alex Rousskov
   5  *
   6  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   7  * ----------------------------------------------------------
   8  *
   9  *  Squid is the result of efforts by numerous individuals from
  10  *  the Internet community; see the CONTRIBUTORS file for full
  11  *  details.   Many organizations have provided support for Squid's
  12  *  development; see the SPONSORS file for full details.  Squid is
  13  *  Copyrighted (C) 2001 by the Regents of the University of
  14  *  California; see the COPYRIGHT file for full details.  Squid
  15  *  incorporates software developed and/or copyrighted by other
  16  *  sources; see the CREDITS file for full details.
  17  *
  18  *  This program is free software; you can redistribute it and/or modify
  19  *  it under the terms of the GNU General Public License as published by
  20  *  the Free Software Foundation; either version 2 of the License, or
  21  *  (at your option) any later version.
  22  *
  23  *  This program is distributed in the hope that it will be useful,
  24  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  25  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  26  *  GNU General Public License for more details.
  27  *
  28  *  You should have received a copy of the GNU General Public License
  29  *  along with this program; if not, write to the Free Software
  30  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  31  *
  32  */
  33
  34 #include "squid.h"
  35 #include "Debug.h"
  36 #include "enums.h"
  37 #include "HttpHdrContRange.h"
  38 #include "HttpHeaderTools.h"
  39 #include "Mem.h"
  40
  41 /*
  42  *    Currently only byte ranges are supported
  43  *
  44  *    Content-Range = "Content-Range" ":" content-range-spec
  45  *    content-range-spec      = byte-content-range-spec
  46  *    byte-content-range-spec = bytes-unit SP
  47  *                              ( byte-range-resp-spec | "*") "/"
  48  *                              ( entity-length | "*" )
  49  *    byte-range-resp-spec = first-byte-pos "-" last-byte-pos
  50  *    entity-length        = 1*DIGIT
  51  */
  52
  53 /* local constants */
  54 #define range_spec_unknown (-1)
  55
  56 /* local routines */
  57 #define known_spec(s) ((s) != range_spec_unknown)
  58 #define size_min(a,b) ((a) <= (b) ? (a) : (b))
  59 #define size_diff(a,b) ((a) >= (b) ? ((a)-(b)) : 0)
  60
  61 /* globals */
  62
  63 /* parses range-resp-spec and inits spec, returns true on success */
  64 static int
  65 httpHdrRangeRespSpecParseInit(HttpHdrRangeSpec * spec, const char *field, int flen)
  66 {
  67     const char *p;
  68     assert(spec);
  69     spec->offset = spec->length = range_spec_unknown;
  70
  71     if (flen < 2)
  72         return 0;
  73
  74     /* is spec given ? */
  75     if (*field == '*')
  76         return 1;
  77
  78     /* check format, must be %d-%d */
  79     if (!((p = strchr(field, '-')) && (p - field < flen))) {
  80         debugs(68, 2, "invalid (no '-') resp-range-spec near: '" << field << "'");
  81         return 0;
  82     }
  83
  84     /* parse offset */
  85     if (!httpHeaderParseOffset(field, &spec->offset))
  86         return 0;
  87
  88     /* Additional check for BUG2155 - there MUST BE first-byte-pos and it MUST be positive*/
  89     if (spec->offset < 0) {
  90         debugs(68, 2, "invalid (no first-byte-pos or it is negative) resp-range-spec near: '" << field << "'");
  91         return 0;
  92     }
  93
  94     ++p;
  95
  96     /* do we have last-pos ? */
  97     if (p - field >= flen) {
  98         debugs(68, 2, "invalid (no last-byte-pos) resp-range-spec near: '" << field << "'");
  99         return 0;
 100     }
 101
 102     int64_t last_pos;
 103
 104     if (!httpHeaderParseOffset(p, &last_pos))
 105         return 0;
 106
 107     if (last_pos < spec->offset) {
 108         debugs(68, 2, "invalid (negative last-byte-pos) resp-range-spec near: '" << field << "'");
 109         return 0;
 110     }
 111
 112     spec->length = size_diff(last_pos + 1, spec->offset);
 113
 114     /* we managed to parse, check if the result makes sence */
 115     if (spec->length <= 0) {
 116         debugs(68, 2, "invalid range (" << spec->offset << " += " <<
 117                (long int) spec->length << ") in resp-range-spec near: '" << field << "'");
 118         return 0;
 119     }
 120
 121     return 1;
 122 }
 123
 124 static void
 125 httpHdrRangeRespSpecPackInto(const HttpHdrRangeSpec * spec, Packer * p)
 126 {
 127     /* Ensure typecast is safe */
 128     assert (spec->length >= 0);
 129
 130     if (!known_spec(spec->offset) || !known_spec(spec->length))
 131         packerPrintf(p, "*");
 132     else
 133         packerPrintf(p, "bytes %" PRId64 "-%" PRId64,
 134                      spec->offset, spec->offset + spec->length - 1);
 135 }
 136
 137 /*
 138  * Content Range
 139  */
 140
 141 HttpHdrContRange *
 142 httpHdrContRangeCreate(void)
 143 {
 144     HttpHdrContRange *r = (HttpHdrContRange *)memAllocate(MEM_HTTP_HDR_CONTENT_RANGE);
 145     r->spec.offset = r->spec.length = range_spec_unknown;
 146     r->elength = range_spec_unknown;
 147     return r;
 148 }
 149
 150 HttpHdrContRange *
 151 httpHdrContRangeParseCreate(const char *str)
 152 {
 153     HttpHdrContRange *r = httpHdrContRangeCreate();
 154
 155     if (!httpHdrContRangeParseInit(r, str)) {
 156         httpHdrContRangeDestroy(r);
 157         r = NULL;
 158     }
 159
 160     return r;
 161 }
 162
 163 /* returns true if ranges are valid; inits HttpHdrContRange */
 164 int
 165 httpHdrContRangeParseInit(HttpHdrContRange * range, const char *str)
 166 {
 167     const char *p;
 168     assert(range && str);
 169     debugs(68, 8, "parsing content-range field: '" << str << "'");
 170     /* check range type */
 171
 172     if (strncasecmp(str, "bytes ", 6))
 173         return 0;
 174
 175     str += 6;
 176
 177     /* split */
 178     if (!(p = strchr(str, '/')))
 179         return 0;
 180
 181     if (*str == '*')
 182         range->spec.offset = range->spec.length = range_spec_unknown;
 183     else if (!httpHdrRangeRespSpecParseInit(&range->spec, str, p - str))
 184         return 0;
 185
 186     ++p;
 187
 188     if (*p == '*')
 189         range->elength = range_spec_unknown;
 190     else if (!httpHeaderParseOffset(p, &range->elength))
 191         return 0;
 192     else if (range->elength <= 0) {
 193         /* Additional paranoidal check for BUG2155 - entity-length MUST be > 0 */
 194         debugs(68, 2, "invalid (entity-length is negative) content-range-spec near: '" << str << "'");
 195         return 0;
 196     } else if (known_spec(range->spec.length) && range->elength < (range->spec.offset + range->spec.length)) {
 197         debugs(68, 2, "invalid (range is outside entity-length) content-range-spec near: '" << str << "'");
 198         return 0;
 199     }
 200
 201     debugs(68, 8, "parsed content-range field: " <<
 202            (long int) range->spec.offset << "-" <<
 203            (long int) range->spec.offset + range->spec.length - 1 << " / " <<
 204            (long int) range->elength);
 205
 206     return 1;
 207 }
 208
 209 void
 210 httpHdrContRangeDestroy(HttpHdrContRange * range)
 211 {
 212     assert(range);
 213     memFree(range, MEM_HTTP_HDR_CONTENT_RANGE);
 214 }
 215
 216 HttpHdrContRange *
 217 httpHdrContRangeDup(const HttpHdrContRange * range)
 218 {
 219     HttpHdrContRange *dup;
 220     assert(range);
 221     dup = httpHdrContRangeCreate();
 222     *dup = *range;
 223     return dup;
 224 }
 225
 226 void
 227 httpHdrContRangePackInto(const HttpHdrContRange * range, Packer * p)
 228 {
 229     assert(range && p);
 230     httpHdrRangeRespSpecPackInto(&range->spec, p);
 231     /* Ensure typecast is safe */
 232     assert (range->elength >= 0);
 233
 234     if (!known_spec(range->elength))
 235         packerPrintf(p, "/*");
 236     else
 237         packerPrintf(p, "/%" PRId64, range->elength);
 238 }
 239
 240 void
 241 httpHdrContRangeSet(HttpHdrContRange * cr, HttpHdrRangeSpec spec, int64_t ent_len)
 242 {
 243     assert(cr && ent_len >= 0);
 244     cr->spec = spec;
 245     cr->elength = ent_len;
 246 }