1 /* Licensed to the Apache Software Foundation (ASF) under one or more
2 * contributor license agreements. See the NOTICE file distributed with
3 * this work for additional information regarding copyright ownership.
4 * The ASF licenses this file to You under the Apache License, Version 2.0
5 * (the "License"); you may not use this file except in compliance with
6 * the License. You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
18 * chunk_filter.c --- HTTP/1.1 chunked transfer encoding filter.
21 #include "apr_strings.h"
22 #include "apr_thread_proc.h" /* for RLIMIT stuff */
24 #define APR_WANT_STRFUNC
29 #include "http_config.h"
30 #include "http_connection.h"
31 #include "http_core.h"
32 #include "http_protocol.h" /* For index_of_response(). Grump. */
33 #include "http_request.h"
35 #include "util_filter.h"
36 #include "util_ebcdic.h"
38 #include "scoreboard.h"
43 * A pointer to this is used to memorize in the filter context that a bad
44 * gateway error bucket had been seen. It is used as an invented unique pointer.
46 static char bad_gateway_seen;
48 apr_status_t ap_http_chunk_filter(ap_filter_t *f, apr_bucket_brigade *b)
50 #define ASCII_CRLF "\015\012"
51 #define ASCII_ZERO "\060"
52 conn_rec *c = f->r->connection;
53 apr_bucket_brigade *more;
57 for (more = NULL; b; b = more, more = NULL) {
59 apr_bucket *eos = NULL;
60 apr_bucket *flush = NULL;
61 /* XXX: chunk_hdr must remain at this scope since it is used in a
64 char chunk_hdr[20]; /* enough space for the snprintf below */
67 for (e = APR_BRIGADE_FIRST(b);
68 e != APR_BRIGADE_SENTINEL(b);
69 e = APR_BUCKET_NEXT(e))
71 if (APR_BUCKET_IS_EOS(e)) {
72 /* there shouldn't be anything after the eos */
76 if (AP_BUCKET_IS_ERROR(e)
77 && (((ap_bucket_error *)(e->data))->status
78 == HTTP_BAD_GATEWAY)) {
80 * We had a broken backend. Memorize this in the filter
83 f->ctx = &bad_gateway_seen;
86 if (APR_BUCKET_IS_FLUSH(e)) {
88 more = apr_brigade_split(b, APR_BUCKET_NEXT(e));
91 else if (e->length == (apr_size_t)-1) {
92 /* unknown amount of data (e.g. a pipe) */
96 rv = apr_bucket_read(e, &data, &len, APR_BLOCK_READ);
97 if (rv != APR_SUCCESS) {
102 * There may be a new next bucket representing the
103 * rest of the data stream on which a read() may
104 * block so we pass down what we have so far.
107 more = apr_brigade_split(b, APR_BUCKET_NEXT(e));
111 /* If there was nothing in this bucket then we can
112 * safely move on to the next one without pausing
113 * to pass down what we have counted up so far.
124 * XXX: if there aren't very many bytes at this point it may
125 * be a good idea to set them aside and return for more,
126 * unless we haven't finished counting this brigade yet.
128 /* if there are content bytes, then wrap them in a chunk */
132 * Insert the chunk header, specifying the number of bytes in
135 hdr_len = apr_snprintf(chunk_hdr, sizeof(chunk_hdr),
136 "%" APR_UINT64_T_HEX_FMT CRLF, (apr_uint64_t)bytes);
137 ap_xlate_proto_to_ascii(chunk_hdr, hdr_len);
138 e = apr_bucket_transient_create(chunk_hdr, hdr_len,
140 APR_BRIGADE_INSERT_HEAD(b, e);
143 * Insert the end-of-chunk CRLF before an EOS or
144 * FLUSH bucket, or appended to the brigade
146 e = apr_bucket_immortal_create(ASCII_CRLF, 2, c->bucket_alloc);
148 APR_BUCKET_INSERT_BEFORE(eos, e);
150 else if (flush != NULL) {
151 APR_BUCKET_INSERT_BEFORE(flush, e);
154 APR_BRIGADE_INSERT_TAIL(b, e);
158 /* RFC 2616, Section 3.6.1
160 * If there is an EOS bucket, then prefix it with:
161 * 1) the last-chunk marker ("0" CRLF)
163 * 3) the end-of-chunked body CRLF
165 * We only do this if we have not seen an error bucket with
166 * status HTTP_BAD_GATEWAY. We have memorized an
167 * error bucket that we had seen in the filter context.
168 * The error bucket with status HTTP_BAD_GATEWAY indicates that the
169 * connection to the backend (mod_proxy) broke in the middle of the
170 * response. In order to signal the client that something went wrong
171 * we do not create the last-chunk marker and set c->keepalive to
172 * AP_CONN_CLOSE in the core output filter.
174 * XXX: it would be nice to combine this with the end-of-chunk
175 * marker above, but this is a bit more straight-forward for
178 if (eos && !f->ctx) {
179 /* XXX: (2) trailers ... does not yet exist */
180 e = apr_bucket_immortal_create(ASCII_ZERO ASCII_CRLF
182 ASCII_CRLF, 5, c->bucket_alloc);
183 APR_BUCKET_INSERT_BEFORE(eos, e);
186 /* pass the brigade to the next filter. */
187 rv = ap_pass_brigade(f->next, b);
188 if (rv != APR_SUCCESS || eos != NULL) {