src/HttpHdrContRange.cc

   1 /*
   2  * Copyright (C) 1996-2016 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 /* DEBUG: section 68    HTTP Content-Range Header */
  10
  11 #include "squid.h"
  12 #include "base/Packable.h"
  13 #include "Debug.h"
  14 #include "enums.h"
  15 #include "HttpHdrContRange.h"
  16 #include "HttpHeaderTools.h"
  17
  18 /*
  19  *    Currently only byte ranges are supported
  20  *
  21  *    Content-Range = "Content-Range" ":" content-range-spec
  22  *    content-range-spec      = byte-content-range-spec
  23  *    byte-content-range-spec = bytes-unit SP
  24  *                              ( byte-range-resp-spec | "*") "/"
  25  *                              ( entity-length | "*" )
  26  *    byte-range-resp-spec = first-byte-pos "-" last-byte-pos
  27  *    entity-length        = 1*DIGIT
  28  */
  29
  30 /* local constants */
  31 #define range_spec_unknown (-1)
  32
  33 /* local routines */
  34 #define known_spec(s) ((s) != range_spec_unknown)
  35 #define size_min(a,b) ((a) <= (b) ? (a) : (b))
  36 #define size_diff(a,b) ((a) >= (b) ? ((a)-(b)) : 0)
  37
  38 /* globals */
  39
  40 /* parses range-resp-spec and inits spec, returns true on success */
  41 static int
  42 httpHdrRangeRespSpecParseInit(HttpHdrRangeSpec * spec, const char *field, int flen)
  43 {
  44     const char *p;
  45     assert(spec);
  46     spec->offset = spec->length = range_spec_unknown;
  47
  48     if (flen < 2)
  49         return 0;
  50
  51     /* is spec given ? */
  52     if (*field == '*')
  53         return 1;
  54
  55     /* check format, must be %d-%d */
  56     if (!((p = strchr(field, '-')) && (p - field < flen))) {
  57         debugs(68, 2, "invalid (no '-') resp-range-spec near: '" << field << "'");
  58         return 0;
  59     }
  60
  61     /* parse offset */
  62     if (!httpHeaderParseOffset(field, &spec->offset))
  63         return 0;
  64
  65     /* Additional check for BUG2155 - there MUST BE first-byte-pos and it MUST be positive*/
  66     if (spec->offset < 0) {
  67         debugs(68, 2, "invalid (no first-byte-pos or it is negative) resp-range-spec near: '" << field << "'");
  68         return 0;
  69     }
  70
  71     ++p;
  72
  73     /* do we have last-pos ? */
  74     if (p - field >= flen) {
  75         debugs(68, 2, "invalid (no last-byte-pos) resp-range-spec near: '" << field << "'");
  76         return 0;
  77     }
  78
  79     int64_t last_pos;
  80
  81     if (!httpHeaderParseOffset(p, &last_pos))
  82         return 0;
  83
  84     if (last_pos < spec->offset) {
  85         debugs(68, 2, "invalid (negative last-byte-pos) resp-range-spec near: '" << field << "'");
  86         return 0;
  87     }
  88
  89     spec->length = size_diff(last_pos + 1, spec->offset);
  90
  91     /* we managed to parse, check if the result makes sence */
  92     if (spec->length <= 0) {
  93         debugs(68, 2, "invalid range (" << spec->offset << " += " <<
  94                (long int) spec->length << ") in resp-range-spec near: '" << field << "'");
  95         return 0;
  96     }
  97
  98     return 1;
  99 }
 100
 101 static void
 102 httpHdrRangeRespSpecPackInto(const HttpHdrRangeSpec * spec, Packable * p)
 103 {
 104     /* Ensure typecast is safe */
 105     assert (spec->length >= 0);
 106
 107     if (!known_spec(spec->offset) || !known_spec(spec->length))
 108         p->append("*", 1);
 109     else
 110         p->appendf("bytes %" PRId64 "-%" PRId64, spec->offset, spec->offset + spec->length - 1);
 111 }
 112
 113 /*
 114  * Content Range
 115  */
 116
 117 HttpHdrContRange *
 118 httpHdrContRangeCreate(void)
 119 {
 120     HttpHdrContRange *r = (HttpHdrContRange *)memAllocate(MEM_HTTP_HDR_CONTENT_RANGE);
 121     r->spec.offset = r->spec.length = range_spec_unknown;
 122     r->elength = range_spec_unknown;
 123     return r;
 124 }
 125
 126 HttpHdrContRange *
 127 httpHdrContRangeParseCreate(const char *str)
 128 {
 129     HttpHdrContRange *r = httpHdrContRangeCreate();
 130
 131     if (!httpHdrContRangeParseInit(r, str)) {
 132         httpHdrContRangeDestroy(r);
 133         r = NULL;
 134     }
 135
 136     return r;
 137 }
 138
 139 /* returns true if ranges are valid; inits HttpHdrContRange */
 140 int
 141 httpHdrContRangeParseInit(HttpHdrContRange * range, const char *str)
 142 {
 143     const char *p;
 144     assert(range && str);
 145     debugs(68, 8, "parsing content-range field: '" << str << "'");
 146     /* check range type */
 147
 148     if (strncasecmp(str, "bytes ", 6))
 149         return 0;
 150
 151     str += 6;
 152
 153     /* split */
 154     if (!(p = strchr(str, '/')))
 155         return 0;
 156
 157     if (*str == '*')
 158         range->spec.offset = range->spec.length = range_spec_unknown;
 159     else if (!httpHdrRangeRespSpecParseInit(&range->spec, str, p - str))
 160         return 0;
 161
 162     ++p;
 163
 164     if (*p == '*')
 165         range->elength = range_spec_unknown;
 166     else if (!httpHeaderParseOffset(p, &range->elength))
 167         return 0;
 168     else if (range->elength <= 0) {
 169         /* Additional paranoidal check for BUG2155 - entity-length MUST be > 0 */
 170         debugs(68, 2, "invalid (entity-length is negative) content-range-spec near: '" << str << "'");
 171         return 0;
 172     } else if (known_spec(range->spec.length) && range->elength < (range->spec.offset + range->spec.length)) {
 173         debugs(68, 2, "invalid (range is outside entity-length) content-range-spec near: '" << str << "'");
 174         return 0;
 175     }
 176
 177     debugs(68, 8, "parsed content-range field: " <<
 178            (long int) range->spec.offset << "-" <<
 179            (long int) range->spec.offset + range->spec.length - 1 << " / " <<
 180            (long int) range->elength);
 181
 182     return 1;
 183 }
 184
 185 void
 186 httpHdrContRangeDestroy(HttpHdrContRange * range)
 187 {
 188     assert(range);
 189     memFree(range, MEM_HTTP_HDR_CONTENT_RANGE);
 190 }
 191
 192 HttpHdrContRange *
 193 httpHdrContRangeDup(const HttpHdrContRange * range)
 194 {
 195     HttpHdrContRange *dup;
 196     assert(range);
 197     dup = httpHdrContRangeCreate();
 198     *dup = *range;
 199     return dup;
 200 }
 201
 202 void
 203 httpHdrContRangePackInto(const HttpHdrContRange * range, Packable * p)
 204 {
 205     assert(range && p);
 206     httpHdrRangeRespSpecPackInto(&range->spec, p);
 207     /* Ensure typecast is safe */
 208     assert (range->elength >= 0);
 209
 210     if (!known_spec(range->elength))
 211         p->append("/*", 2);
 212     else
 213         p->appendf("/%" PRId64, range->elength);
 214 }
 215
 216 void
 217 httpHdrContRangeSet(HttpHdrContRange * cr, HttpHdrRangeSpec spec, int64_t ent_len)
 218 {
 219     assert(cr && ent_len >= 0);
 220     cr->spec = spec;
 221     cr->elength = ent_len;
 222 }
 223