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 "Mem.h"
  42 #include "protos.h"
  43
  44 /*
  45  *    Currently only byte ranges are supported
  46  *
  47  *    Content-Range = "Content-Range" ":" content-range-spec
  48  *    content-range-spec      = byte-content-range-spec
  49  *    byte-content-range-spec = bytes-unit SP
  50  *                              ( byte-range-resp-spec | "*") "/"
  51  *                              ( entity-length | "*" )
  52  *    byte-range-resp-spec = first-byte-pos "-" last-byte-pos
  53  *    entity-length        = 1*DIGIT
  54  */
  55
  56
  57 /* local constants */
  58 #define range_spec_unknown (-1)
  59
  60 /* local routines */
  61 #define known_spec(s) ((s) != range_spec_unknown)
  62 #define size_min(a,b) ((a) <= (b) ? (a) : (b))
  63 #define size_diff(a,b) ((a) >= (b) ? ((a)-(b)) : 0)
  64
  65 /* globals */
  66
  67 /* parses range-resp-spec and inits spec, returns true on success */
  68 static int
  69 httpHdrRangeRespSpecParseInit(HttpHdrRangeSpec * spec, const char *field, int flen)
  70 {
  71     const char *p;
  72     assert(spec);
  73     spec->offset = spec->length = range_spec_unknown;
  74
  75     if (flen < 2)
  76         return 0;
  77
  78     /* is spec given ? */
  79     if (*field == '*')
  80         return 1;
  81
  82     /* check format, must be %d-%d */
  83     if (!((p = strchr(field, '-')) && (p - field < flen))) {
  84         debugs(68, 2, "invalid (no '-') resp-range-spec near: '" << field << "'");
  85         return 0;
  86     }
  87
  88     /* parse offset */
  89     if (!httpHeaderParseOffset(field, &spec->offset))
  90         return 0;
  91
  92     /* Additional check for BUG2155 - there MUST BE first-byte-pos and it MUST be positive*/
  93     if (spec->offset < 0) {
  94         debugs(68, 2, "invalid (no first-byte-pos or it is negative) resp-range-spec near: '" << field << "'");
  95         return 0;
  96     }
  97
  98     ++p;
  99
 100     /* do we have last-pos ? */
 101     if (p - field >= flen) {
 102         debugs(68, 2, "invalid (no last-byte-pos) resp-range-spec near: '" << field << "'");
 103         return 0;
 104     }
 105
 106     int64_t last_pos;
 107
 108     if (!httpHeaderParseOffset(p, &last_pos))
 109         return 0;
 110
 111     if (last_pos < spec->offset) {
 112         debugs(68, 2, "invalid (negative last-byte-pos) resp-range-spec near: '" << field << "'");
 113         return 0;
 114     }
 115
 116     spec->length = size_diff(last_pos + 1, spec->offset);
 117
 118     /* we managed to parse, check if the result makes sence */
 119     if (spec->length <= 0) {
 120         debugs(68, 2, "invalid range (" << spec->offset << " += " <<
 121                (long int) spec->length << ") in resp-range-spec near: '" << field << "'");
 122         return 0;
 123     }
 124
 125     return 1;
 126 }
 127
 128 static void
 129 httpHdrRangeRespSpecPackInto(const HttpHdrRangeSpec * spec, Packer * p)
 130 {
 131     /* Ensure typecast is safe */
 132     assert (spec->length >= 0);
 133
 134     if (!known_spec(spec->offset) || !known_spec(spec->length))
 135         packerPrintf(p, "*");
 136     else
 137         packerPrintf(p, "bytes %" PRId64 "-%" PRId64,
 138                      spec->offset, spec->offset + spec->length - 1);
 139 }
 140
 141 /*
 142  * Content Range
 143  */
 144
 145 HttpHdrContRange *
 146 httpHdrContRangeCreate(void)
 147 {
 148     HttpHdrContRange *r = (HttpHdrContRange *)memAllocate(MEM_HTTP_HDR_CONTENT_RANGE);
 149     r->spec.offset = r->spec.length = range_spec_unknown;
 150     r->elength = range_spec_unknown;
 151     return r;
 152 }
 153
 154 HttpHdrContRange *
 155 httpHdrContRangeParseCreate(const char *str)
 156 {
 157     HttpHdrContRange *r = httpHdrContRangeCreate();
 158
 159     if (!httpHdrContRangeParseInit(r, str)) {
 160         httpHdrContRangeDestroy(r);
 161         r = NULL;
 162     }
 163
 164     return r;
 165 }
 166
 167 /* returns true if ranges are valid; inits HttpHdrContRange */
 168 int
 169 httpHdrContRangeParseInit(HttpHdrContRange * range, const char *str)
 170 {
 171     const char *p;
 172     assert(range && str);
 173     debugs(68, 8, "parsing content-range field: '" << str << "'");
 174     /* check range type */
 175
 176     if (strncasecmp(str, "bytes ", 6))
 177         return 0;
 178
 179     str += 6;
 180
 181     /* split */
 182     if (!(p = strchr(str, '/')))
 183         return 0;
 184
 185     if (*str == '*')
 186         range->spec.offset = range->spec.length = range_spec_unknown;
 187     else if (!httpHdrRangeRespSpecParseInit(&range->spec, str, p - str))
 188         return 0;
 189
 190     ++p;
 191
 192     if (*p == '*')
 193         range->elength = range_spec_unknown;
 194     else if (!httpHeaderParseOffset(p, &range->elength))
 195         return 0;
 196     else if (range->elength <= 0) {
 197         /* Additional paranoidal check for BUG2155 - entity-length MUST be > 0 */
 198         debugs(68, 2, "invalid (entity-length is negative) content-range-spec near: '" << str << "'");
 199         return 0;
 200     } else if (known_spec(range->spec.length) && range->elength < (range->spec.offset + range->spec.length)) {
 201         debugs(68, 2, "invalid (range is outside entity-length) content-range-spec near: '" << str << "'");
 202         return 0;
 203     }
 204
 205     debugs(68, 8, "parsed content-range field: " <<
 206            (long int) range->spec.offset << "-" <<
 207            (long int) range->spec.offset + range->spec.length - 1 << " / " <<
 208            (long int) range->elength);
 209
 210     return 1;
 211 }
 212
 213 void
 214 httpHdrContRangeDestroy(HttpHdrContRange * range)
 215 {
 216     assert(range);
 217     memFree(range, MEM_HTTP_HDR_CONTENT_RANGE);
 218 }
 219
 220 HttpHdrContRange *
 221 httpHdrContRangeDup(const HttpHdrContRange * range)
 222 {
 223     HttpHdrContRange *dup;
 224     assert(range);
 225     dup = httpHdrContRangeCreate();
 226     *dup = *range;
 227     return dup;
 228 }
 229
 230 void
 231 httpHdrContRangePackInto(const HttpHdrContRange * range, Packer * p)
 232 {
 233     assert(range && p);
 234     httpHdrRangeRespSpecPackInto(&range->spec, p);
 235     /* Ensure typecast is safe */
 236     assert (range->elength >= 0);
 237
 238     if (!known_spec(range->elength))
 239         packerPrintf(p, "/*");
 240     else
 241         packerPrintf(p, "/%" PRId64, range->elength);
 242 }
 243
 244 void
 245 httpHdrContRangeSet(HttpHdrContRange * cr, HttpHdrRangeSpec spec, int64_t ent_len)
 246 {
 247     assert(cr && ent_len >= 0);
 248     cr->spec = spec;
 249     cr->elength = ent_len;
 250 }