1 /***************************************************************************
3 * Project ___| | | | _ \| |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
8 * Copyright (C) 1998 - 2022, Daniel Stenberg, <daniel@haxx.se>, et al.
10 * This software is licensed as described in the file COPYING, which
11 * you should have received as part of this distribution. The terms
12 * are also available at https://curl.se/docs/copyright.html.
14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15 * copies of the Software, and permit persons to whom the Software is
16 * furnished to do so, under the terms of the COPYING file.
18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19 * KIND, either express or implied.
21 * SPDX-License-Identifier: curl
23 ***************************************************************************/
25 #include "curl_setup.h"
27 #ifndef CURL_DISABLE_HTTP
29 #include "urldata.h" /* it includes http_chunks.h */
30 #include "sendf.h" /* for the client write stuff */
32 #include "content_encoding.h"
34 #include "strtoofft.h"
37 /* The last #include files should be: */
38 #include "curl_memory.h"
42 * Chunk format (simplified):
44 * <HEX SIZE>[ chunk extension ] CRLF
47 * Highlights from RFC2616 section 3.6 say:
49 The chunked encoding modifies the body of a message in order to
50 transfer it as a series of chunks, each with its own size indicator,
51 followed by an OPTIONAL trailer containing entity-header fields. This
52 allows dynamically produced content to be transferred along with the
53 information necessary for the recipient to verify that it has
54 received the full message.
61 chunk = chunk-size [ chunk-extension ] CRLF
64 last-chunk = 1*("0") [ chunk-extension ] CRLF
66 chunk-extension= *( ";" chunk-ext-name [ "=" chunk-ext-val ] )
67 chunk-ext-name = token
68 chunk-ext-val = token | quoted-string
69 chunk-data = chunk-size(OCTET)
70 trailer = *(entity-header CRLF)
72 The chunk-size field is a string of hex digits indicating the size of
73 the chunk. The chunked encoding is ended by any chunk whose size is
74 zero, followed by the trailer, which is terminated by an empty line.
78 #define isxdigit_ascii(x) Curl_isxdigit(x)
80 void Curl_httpchunk_init(struct Curl_easy *data)
82 struct connectdata *conn = data->conn;
83 struct Curl_chunker *chunk = &conn->chunk;
84 chunk->hexindex = 0; /* start at 0 */
85 chunk->state = CHUNK_HEX; /* we get hex first! */
86 Curl_dyn_init(&conn->trailer, DYN_H1_TRAILER);
90 * chunk_read() returns a OK for normal operations, or a positive return code
91 * for errors. STOP means this sequence of chunks is complete. The 'wrote'
92 * argument is set to tell the caller how many bytes we actually passed to the
93 * client (for byte-counting and whatever).
95 * The states and the state-machine is further explained in the header file.
97 * This function always uses ASCII hex values to accommodate non-ASCII hosts.
98 * For example, 0x0d and 0x0a are used instead of '\r' and '\n'.
100 CHUNKcode Curl_httpchunk_read(struct Curl_easy *data,
106 CURLcode result = CURLE_OK;
107 struct connectdata *conn = data->conn;
108 struct Curl_chunker *ch = &conn->chunk;
109 struct SingleRequest *k = &data->req;
111 curl_off_t length = (curl_off_t)datalen;
113 *wrote = 0; /* nothing's written yet */
115 /* the original data is written to the client, but we go on with the
116 chunk read process, to properly calculate the content length*/
117 if(data->set.http_te_skip && !k->ignorebody) {
118 result = Curl_client_write(data, CLIENTWRITE_BODY, datap, datalen);
121 return CHUNKE_PASSTHRU_ERROR;
128 if(ISXDIGIT(*datap)) {
129 if(ch->hexindex < CHUNK_MAXNUM_LEN) {
130 ch->hexbuffer[ch->hexindex] = *datap;
136 return CHUNKE_TOO_LONG_HEX; /* longer hex than we support */
141 if(0 == ch->hexindex)
142 /* This is illegal data, we received junk where we expected
143 a hexadecimal digit. */
144 return CHUNKE_ILLEGAL_HEX;
146 /* length and datap are unmodified */
147 ch->hexbuffer[ch->hexindex] = 0;
149 if(curlx_strtoofft(ch->hexbuffer, &endptr, 16, &ch->datasize))
150 return CHUNKE_ILLEGAL_HEX;
151 ch->state = CHUNK_LF; /* now wait for the CRLF */
156 /* waiting for the LF after a chunk size */
158 /* we're now expecting data to come, unless size was zero! */
159 if(0 == ch->datasize) {
160 ch->state = CHUNK_TRAILER; /* now check for trailers */
163 ch->state = CHUNK_DATA;
171 /* We expect 'datasize' of data. We have 'length' right now, it can be
172 more or less than 'datasize'. Get the smallest piece.
174 piece = curlx_sotouz((ch->datasize >= length)?length:ch->datasize);
176 /* Write the data portion available */
177 if(!data->set.http_te_skip && !k->ignorebody) {
178 if(!data->set.http_ce_skip && k->writer_stack)
179 result = Curl_unencode_write(data, k->writer_stack, datap, piece);
181 result = Curl_client_write(data, CLIENTWRITE_BODY, datap, piece);
185 return CHUNKE_PASSTHRU_ERROR;
190 ch->datasize -= piece; /* decrease amount left to expect */
191 datap += piece; /* move read pointer forward */
192 length -= piece; /* decrease space left in this round */
194 if(0 == ch->datasize)
195 /* end of data this round, we now expect a trailing CRLF */
196 ch->state = CHUNK_POSTLF;
201 /* The last one before we go back to hex state and start all over. */
202 Curl_httpchunk_init(data); /* sets state back to CHUNK_HEX */
204 else if(*datap != 0x0d)
205 return CHUNKE_BAD_CHUNK;
211 if((*datap == 0x0d) || (*datap == 0x0a)) {
212 char *tr = Curl_dyn_ptr(&conn->trailer);
213 /* this is the end of a trailer, but if the trailer was zero bytes
214 there was no trailer and we move on */
218 result = Curl_dyn_addn(&conn->trailer, (char *)STRCONST("\x0d\x0a"));
220 return CHUNKE_OUT_OF_MEMORY;
222 tr = Curl_dyn_ptr(&conn->trailer);
223 trlen = Curl_dyn_len(&conn->trailer);
224 if(!data->set.http_te_skip) {
225 result = Curl_client_write(data,
226 CLIENTWRITE_HEADER|CLIENTWRITE_TRAILER,
230 return CHUNKE_PASSTHRU_ERROR;
233 Curl_dyn_reset(&conn->trailer);
234 ch->state = CHUNK_TRAILER_CR;
236 /* already on the LF */
240 /* no trailer, we're on the final CRLF pair */
241 ch->state = CHUNK_TRAILER_POSTCR;
242 break; /* don't advance the pointer */
246 result = Curl_dyn_addn(&conn->trailer, datap, 1);
248 return CHUNKE_OUT_OF_MEMORY;
254 case CHUNK_TRAILER_CR:
256 ch->state = CHUNK_TRAILER_POSTCR;
261 return CHUNKE_BAD_CHUNK;
264 case CHUNK_TRAILER_POSTCR:
265 /* We enter this state when a CR should arrive so we expect to
266 have to first pass a CR before we wait for LF */
267 if((*datap != 0x0d) && (*datap != 0x0a)) {
268 /* not a CR then it must be another header in the trailer */
269 ch->state = CHUNK_TRAILER;
277 /* now wait for the final LF */
278 ch->state = CHUNK_STOP;
285 /* Record the length of any data left in the end of the buffer
286 even if there's no more chunks to read */
287 ch->datasize = curlx_sotouz(length);
289 return CHUNKE_STOP; /* return stop */
292 return CHUNKE_BAD_CHUNK;
298 const char *Curl_chunked_strerror(CHUNKcode code)
303 case CHUNKE_TOO_LONG_HEX:
304 return "Too long hexadecimal number";
305 case CHUNKE_ILLEGAL_HEX:
306 return "Illegal or missing hexadecimal sequence";
307 case CHUNKE_BAD_CHUNK:
308 return "Malformed encoding found";
309 case CHUNKE_PASSTHRU_ERROR:
310 DEBUGASSERT(0); /* never used */
312 case CHUNKE_BAD_ENCODING:
313 return "Bad content-encoding found";
314 case CHUNKE_OUT_OF_MEMORY:
315 return "Out of memory";
319 #endif /* CURL_DISABLE_HTTP */