summaryrefslogtreecommitdiff
path: root/libavformat/http.c
blob: eea8dedcbc36de58824d1a86039d17ac3d93578d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
/*
 * HTTP protocol for avconv client
 * Copyright (c) 2000, 2001 Fabrice Bellard
 *
 * This file is part of Libav.
 *
 * Libav is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * Libav is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "libavutil/avstring.h"
#include "avformat.h"
#include <unistd.h>
#include "internal.h"
#include "network.h"
#include "http.h"
#include "os_support.h"
#include "httpauth.h"
#include "url.h"
#include "libavutil/opt.h"

/* XXX: POST protocol is not completely implemented because avconv uses
   only a subset of it. */

/* used for protocol handling */
#define BUFFER_SIZE 1024
#define MAX_REDIRECTS 8

typedef struct {
    const AVClass *class;
    URLContext *hd;
    unsigned char buffer[BUFFER_SIZE], *buf_ptr, *buf_end;
    int line_count;
    int http_code;
    int64_t chunksize;      /**< Used if "Transfer-Encoding: chunked" otherwise -1. */
    int64_t off, filesize;
    char location[MAX_URL_SIZE];
    HTTPAuthState auth_state;
    HTTPAuthState proxy_auth_state;
    char *headers;
    int willclose;          /**< Set if the server correctly handles Connection: close and will close the connection after feeding us the content. */
    int chunked_post;
} HTTPContext;

#define OFFSET(x) offsetof(HTTPContext, x)
#define D AV_OPT_FLAG_DECODING_PARAM
#define E AV_OPT_FLAG_ENCODING_PARAM
static const AVOption options[] = {
{"chunked_post", "use chunked transfer-encoding for posts", OFFSET(chunked_post), AV_OPT_TYPE_INT, {.dbl = 1}, 0, 1, E },
{"headers", "custom HTTP headers, can override built in default headers", OFFSET(headers), AV_OPT_TYPE_STRING, { 0 }, 0, 0, D|E },
{NULL}
};
#define HTTP_CLASS(flavor)\
static const AVClass flavor ## _context_class = {\
    .class_name     = #flavor,\
    .item_name      = av_default_item_name,\
    .option         = options,\
    .version        = LIBAVUTIL_VERSION_INT,\
}

HTTP_CLASS(http);
HTTP_CLASS(https);

static int http_connect(URLContext *h, const char *path, const char *local_path,
                        const char *hoststr, const char *auth,
                        const char *proxyauth, int *new_location);

void ff_http_init_auth_state(URLContext *dest, const URLContext *src)
{
    memcpy(&((HTTPContext*)dest->priv_data)->auth_state,
           &((HTTPContext*)src->priv_data)->auth_state, sizeof(HTTPAuthState));
    memcpy(&((HTTPContext*)dest->priv_data)->proxy_auth_state,
           &((HTTPContext*)src->priv_data)->proxy_auth_state,
           sizeof(HTTPAuthState));
}

/* return non zero if error */
static int http_open_cnx(URLContext *h)
{
    const char *path, *proxy_path, *lower_proto = "tcp", *local_path;
    char hostname[1024], hoststr[1024], proto[10];
    char auth[1024], proxyauth[1024] = "";
    char path1[1024];
    char buf[1024], urlbuf[1024];
    int port, use_proxy, err, location_changed = 0, redirects = 0;
    HTTPAuthType cur_auth_type, cur_proxy_auth_type;
    HTTPContext *s = h->priv_data;
    URLContext *hd = NULL;

    proxy_path = getenv("http_proxy");
    use_proxy = (proxy_path != NULL) && !getenv("no_proxy") &&
        av_strstart(proxy_path, "http://", NULL);

    /* fill the dest addr */
 redo:
    /* needed in any case to build the host string */
    av_url_split(proto, sizeof(proto), auth, sizeof(auth),
                 hostname, sizeof(hostname), &port,
                 path1, sizeof(path1), s->location);
    ff_url_join(hoststr, sizeof(hoststr), NULL, NULL, hostname, port, NULL);

    if (!strcmp(proto, "https")) {
        lower_proto = "tls";
        use_proxy = 0;
        if (port < 0)
            port = 443;
    }
    if (port < 0)
        port = 80;

    if (path1[0] == '\0')
        path = "/";
    else
        path = path1;
    local_path = path;
    if (use_proxy) {
        /* Reassemble the request URL without auth string - we don't
         * want to leak the auth to the proxy. */
        ff_url_join(urlbuf, sizeof(urlbuf), proto, NULL, hostname, port, "%s",
                    path1);
        path = urlbuf;
        av_url_split(NULL, 0, proxyauth, sizeof(proxyauth),
                     hostname, sizeof(hostname), &port, NULL, 0, proxy_path);
    }

    ff_url_join(buf, sizeof(buf), lower_proto, NULL, hostname, port, NULL);
    err = ffurl_open(&hd, buf, AVIO_FLAG_READ_WRITE,
                     &h->interrupt_callback, NULL);
    if (err < 0)
        goto fail;

    s->hd = hd;
    cur_auth_type = s->auth_state.auth_type;
    cur_proxy_auth_type = s->auth_state.auth_type;
    if (http_connect(h, path, local_path, hoststr, auth, proxyauth, &location_changed) < 0)
        goto fail;
    if (s->http_code == 401) {
        if (cur_auth_type == HTTP_AUTH_NONE && s->auth_state.auth_type != HTTP_AUTH_NONE) {
            ffurl_close(hd);
            goto redo;
        } else
            goto fail;
    }
    if (s->http_code == 407) {
        if (cur_proxy_auth_type == HTTP_AUTH_NONE &&
            s->proxy_auth_state.auth_type != HTTP_AUTH_NONE) {
            ffurl_close(hd);
            goto redo;
        } else
            goto fail;
    }
    if ((s->http_code == 301 || s->http_code == 302 || s->http_code == 303 || s->http_code == 307)
        && location_changed == 1) {
        /* url moved, get next */
        ffurl_close(hd);
        if (redirects++ >= MAX_REDIRECTS)
            return AVERROR(EIO);
        location_changed = 0;
        goto redo;
    }
    return 0;
 fail:
    if (hd)
        ffurl_close(hd);
    s->hd = NULL;
    return AVERROR(EIO);
}

static int http_open(URLContext *h, const char *uri, int flags)
{
    HTTPContext *s = h->priv_data;

    h->is_streamed = 1;

    s->filesize = -1;
    av_strlcpy(s->location, uri, sizeof(s->location));

    if (s->headers) {
        int len = strlen(s->headers);
        if (len < 2 || strcmp("\r\n", s->headers + len - 2))
            av_log(h, AV_LOG_WARNING, "No trailing CRLF found in HTTP header.\n");
    }

    return http_open_cnx(h);
}
static int http_getc(HTTPContext *s)
{
    int len;
    if (s->buf_ptr >= s->buf_end) {
        len = ffurl_read(s->hd, s->buffer, BUFFER_SIZE);
        if (len < 0) {
            return AVERROR(EIO);
        } else if (len == 0) {
            return -1;
        } else {
            s->buf_ptr = s->buffer;
            s->buf_end = s->buffer + len;
        }
    }
    return *s->buf_ptr++;
}

static int http_get_line(HTTPContext *s, char *line, int line_size)
{
    int ch;
    char *q;

    q = line;
    for(;;) {
        ch = http_getc(s);
        if (ch < 0)
            return AVERROR(EIO);
        if (ch == '\n') {
            /* process line */
            if (q > line && q[-1] == '\r')
                q--;
            *q = '\0';

            return 0;
        } else {
            if ((q - line) < line_size - 1)
                *q++ = ch;
        }
    }
}

static int process_line(URLContext *h, char *line, int line_count,
                        int *new_location)
{
    HTTPContext *s = h->priv_data;
    char *tag, *p, *end;

    /* end of header */
    if (line[0] == '\0')
        return 0;

    p = line;
    if (line_count == 0) {
        while (!isspace(*p) && *p != '\0')
            p++;
        while (isspace(*p))
            p++;
        s->http_code = strtol(p, &end, 10);

        av_dlog(NULL, "http_code=%d\n", s->http_code);

        /* error codes are 4xx and 5xx, but regard 401 as a success, so we
         * don't abort until all headers have been parsed. */
        if (s->http_code >= 400 && s->http_code < 600 && (s->http_code != 401
            || s->auth_state.auth_type != HTTP_AUTH_NONE) &&
            (s->http_code != 407 || s->proxy_auth_state.auth_type != HTTP_AUTH_NONE)) {
            end += strspn(end, SPACE_CHARS);
            av_log(h, AV_LOG_WARNING, "HTTP error %d %s\n",
                   s->http_code, end);
            return -1;
        }
    } else {
        while (*p != '\0' && *p != ':')
            p++;
        if (*p != ':')
            return 1;

        *p = '\0';
        tag = line;
        p++;
        while (isspace(*p))
            p++;
        if (!av_strcasecmp(tag, "Location")) {
            strcpy(s->location, p);
            *new_location = 1;
        } else if (!av_strcasecmp (tag, "Content-Length") && s->filesize == -1) {
            s->filesize = atoll(p);
        } else if (!av_strcasecmp (tag, "Content-Range")) {
            /* "bytes $from-$to/$document_size" */
            const char *slash;
            if (!strncmp (p, "bytes ", 6)) {
                p += 6;
                s->off = atoll(p);
                if ((slash = strchr(p, '/')) && strlen(slash) > 0)
                    s->filesize = atoll(slash+1);
            }
            h->is_streamed = 0; /* we _can_ in fact seek */
        } else if (!av_strcasecmp(tag, "Accept-Ranges") && !strncmp(p, "bytes", 5)) {
            h->is_streamed = 0;
        } else if (!av_strcasecmp (tag, "Transfer-Encoding") && !av_strncasecmp(p, "chunked", 7)) {
            s->filesize = -1;
            s->chunksize = 0;
        } else if (!av_strcasecmp (tag, "WWW-Authenticate")) {
            ff_http_auth_handle_header(&s->auth_state, tag, p);
        } else if (!av_strcasecmp (tag, "Authentication-Info")) {
            ff_http_auth_handle_header(&s->auth_state, tag, p);
        } else if (!av_strcasecmp (tag, "Proxy-Authenticate")) {
            ff_http_auth_handle_header(&s->proxy_auth_state, tag, p);
        } else if (!av_strcasecmp (tag, "Connection")) {
            if (!strcmp(p, "close"))
                s->willclose = 1;
        }
    }
    return 1;
}

static inline int has_header(const char *str, const char *header)
{
    /* header + 2 to skip over CRLF prefix. (make sure you have one!) */
    if (!str)
        return 0;
    return av_stristart(str, header + 2, NULL) || av_stristr(str, header);
}

static int http_connect(URLContext *h, const char *path, const char *local_path,
                        const char *hoststr, const char *auth,
                        const char *proxyauth, int *new_location)
{
    HTTPContext *s = h->priv_data;
    int post, err;
    char line[1024];
    char headers[1024] = "";
    char *authstr = NULL, *proxyauthstr = NULL;
    int64_t off = s->off;
    int len = 0;
    const char *method;


    /* send http header */
    post = h->flags & AVIO_FLAG_WRITE;
    method = post ? "POST" : "GET";
    authstr = ff_http_auth_create_response(&s->auth_state, auth, local_path,
                                           method);
    proxyauthstr = ff_http_auth_create_response(&s->proxy_auth_state, proxyauth,
                                                local_path, method);

    /* set default headers if needed */
    if (!has_header(s->headers, "\r\nUser-Agent: "))
       len += av_strlcatf(headers + len, sizeof(headers) - len,
                          "User-Agent: %s\r\n", LIBAVFORMAT_IDENT);
    if (!has_header(s->headers, "\r\nAccept: "))
        len += av_strlcpy(headers + len, "Accept: */*\r\n",
                          sizeof(headers) - len);
    if (!has_header(s->headers, "\r\nRange: ") && !post)
        len += av_strlcatf(headers + len, sizeof(headers) - len,
                           "Range: bytes=%"PRId64"-\r\n", s->off);
    if (!has_header(s->headers, "\r\nConnection: "))
        len += av_strlcpy(headers + len, "Connection: close\r\n",
                          sizeof(headers)-len);
    if (!has_header(s->headers, "\r\nHost: "))
        len += av_strlcatf(headers + len, sizeof(headers) - len,
                           "Host: %s\r\n", hoststr);

    /* now add in custom headers */
    if (s->headers)
        av_strlcpy(headers + len, s->headers, sizeof(headers) - len);

    snprintf(s->buffer, sizeof(s->buffer),
             "%s %s HTTP/1.1\r\n"
             "%s"
             "%s"
             "%s"
             "%s%s"
             "\r\n",
             method,
             path,
             post && s->chunked_post ? "Transfer-Encoding: chunked\r\n" : "",
             headers,
             authstr ? authstr : "",
             proxyauthstr ? "Proxy-" : "", proxyauthstr ? proxyauthstr : "");

    av_freep(&authstr);
    av_freep(&proxyauthstr);
    if (ffurl_write(s->hd, s->buffer, strlen(s->buffer)) < 0)
        return AVERROR(EIO);

    /* init input buffer */
    s->buf_ptr = s->buffer;
    s->buf_end = s->buffer;
    s->line_count = 0;
    s->off = 0;
    s->filesize = -1;
    s->willclose = 0;
    if (post) {
        /* Pretend that it did work. We didn't read any header yet, since
         * we've still to send the POST data, but the code calling this
         * function will check http_code after we return. */
        s->http_code = 200;
        return 0;
    }
    s->chunksize = -1;

    /* wait for header */
    for(;;) {
        if (http_get_line(s, line, sizeof(line)) < 0)
            return AVERROR(EIO);

        av_dlog(NULL, "header='%s'\n", line);

        err = process_line(h, line, s->line_count, new_location);
        if (err < 0)
            return err;
        if (err == 0)
            break;
        s->line_count++;
    }

    return (off == s->off) ? 0 : -1;
}


static int http_buf_read(URLContext *h, uint8_t *buf, int size)
{
    HTTPContext *s = h->priv_data;
    int len;
    /* read bytes from input buffer first */
    len = s->buf_end - s->buf_ptr;
    if (len > 0) {
        if (len > size)
            len = size;
        memcpy(buf, s->buf_ptr, len);
        s->buf_ptr += len;
    } else {
        if (!s->willclose && s->filesize >= 0 && s->off >= s->filesize)
            return AVERROR_EOF;
        len = ffurl_read(s->hd, buf, size);
    }
    if (len > 0) {
        s->off += len;
        if (s->chunksize > 0)
            s->chunksize -= len;
    }
    return len;
}

static int http_read(URLContext *h, uint8_t *buf, int size)
{
    HTTPContext *s = h->priv_data;

    if (s->chunksize >= 0) {
        if (!s->chunksize) {
            char line[32];

            for(;;) {
                do {
                    if (http_get_line(s, line, sizeof(line)) < 0)
                        return AVERROR(EIO);
                } while (!*line);    /* skip CR LF from last chunk */

                s->chunksize = strtoll(line, NULL, 16);

                av_dlog(NULL, "Chunked encoding data size: %"PRId64"'\n", s->chunksize);

                if (!s->chunksize)
                    return 0;
                break;
            }
        }
        size = FFMIN(size, s->chunksize);
    }
    return http_buf_read(h, buf, size);
}

/* used only when posting data */
static int http_write(URLContext *h, const uint8_t *buf, int size)
{
    char temp[11] = "";  /* 32-bit hex + CRLF + nul */
    int ret;
    char crlf[] = "\r\n";
    HTTPContext *s = h->priv_data;

    if (!s->chunked_post) {
        /* non-chunked data is sent without any special encoding */
        return ffurl_write(s->hd, buf, size);
    }

    /* silently ignore zero-size data since chunk encoding that would
     * signal EOF */
    if (size > 0) {
        /* upload data using chunked encoding */
        snprintf(temp, sizeof(temp), "%x\r\n", size);

        if ((ret = ffurl_write(s->hd, temp, strlen(temp))) < 0 ||
            (ret = ffurl_write(s->hd, buf, size)) < 0 ||
            (ret = ffurl_write(s->hd, crlf, sizeof(crlf) - 1)) < 0)
            return ret;
    }
    return size;
}

static int http_close(URLContext *h)
{
    int ret = 0;
    char footer[] = "0\r\n\r\n";
    HTTPContext *s = h->priv_data;

    /* signal end of chunked encoding if used */
    if ((h->flags & AVIO_FLAG_WRITE) && s->chunked_post) {
        ret = ffurl_write(s->hd, footer, sizeof(footer) - 1);
        ret = ret > 0 ? 0 : ret;
    }

    if (s->hd)
        ffurl_close(s->hd);
    return ret;
}

static int64_t http_seek(URLContext *h, int64_t off, int whence)
{
    HTTPContext *s = h->priv_data;
    URLContext *old_hd = s->hd;
    int64_t old_off = s->off;
    uint8_t old_buf[BUFFER_SIZE];
    int old_buf_size;

    if (whence == AVSEEK_SIZE)
        return s->filesize;
    else if ((s->filesize == -1 && whence == SEEK_END) || h->is_streamed)
        return -1;

    /* we save the old context in case the seek fails */
    old_buf_size = s->buf_end - s->buf_ptr;
    memcpy(old_buf, s->buf_ptr, old_buf_size);
    s->hd = NULL;
    if (whence == SEEK_CUR)
        off += s->off;
    else if (whence == SEEK_END)
        off += s->filesize;
    s->off = off;

    /* if it fails, continue on old connection */
    if (http_open_cnx(h) < 0) {
        memcpy(s->buffer, old_buf, old_buf_size);
        s->buf_ptr = s->buffer;
        s->buf_end = s->buffer + old_buf_size;
        s->hd = old_hd;
        s->off = old_off;
        return -1;
    }
    ffurl_close(old_hd);
    return off;
}

static int
http_get_file_handle(URLContext *h)
{
    HTTPContext *s = h->priv_data;
    return ffurl_get_file_handle(s->hd);
}

#if CONFIG_HTTP_PROTOCOL
URLProtocol ff_http_protocol = {
    .name                = "http",
    .url_open            = http_open,
    .url_read            = http_read,
    .url_write           = http_write,
    .url_seek            = http_seek,
    .url_close           = http_close,
    .url_get_file_handle = http_get_file_handle,
    .priv_data_size      = sizeof(HTTPContext),
    .priv_data_class     = &http_context_class,
    .flags               = URL_PROTOCOL_FLAG_NETWORK,
};
#endif
#if CONFIG_HTTPS_PROTOCOL
URLProtocol ff_https_protocol = {
    .name                = "https",
    .url_open            = http_open,
    .url_read            = http_read,
    .url_write           = http_write,
    .url_seek            = http_seek,
    .url_close           = http_close,
    .url_get_file_handle = http_get_file_handle,
    .priv_data_size      = sizeof(HTTPContext),
    .priv_data_class     = &https_context_class,
    .flags               = URL_PROTOCOL_FLAG_NETWORK,
};
#endif

#if CONFIG_HTTPPROXY_PROTOCOL
static int http_proxy_close(URLContext *h)
{
    HTTPContext *s = h->priv_data;
    if (s->hd)
        ffurl_close(s->hd);
    return 0;
}

static int http_proxy_open(URLContext *h, const char *uri, int flags)
{
    HTTPContext *s = h->priv_data;
    char hostname[1024], hoststr[1024];
    char auth[1024], pathbuf[1024], *path;
    char line[1024], lower_url[100];
    int port, ret = 0;
    HTTPAuthType cur_auth_type;
    char *authstr;

    h->is_streamed = 1;

    av_url_split(NULL, 0, auth, sizeof(auth), hostname, sizeof(hostname), &port,
                 pathbuf, sizeof(pathbuf), uri);
    ff_url_join(hoststr, sizeof(hoststr), NULL, NULL, hostname, port, NULL);
    path = pathbuf;
    if (*path == '/')
        path++;

    ff_url_join(lower_url, sizeof(lower_url), "tcp", NULL, hostname, port,
                NULL);
redo:
    ret = ffurl_open(&s->hd, lower_url, AVIO_FLAG_READ_WRITE,
                     &h->interrupt_callback, NULL);
    if (ret < 0)
        return ret;

    authstr = ff_http_auth_create_response(&s->proxy_auth_state, auth,
                                           path, "CONNECT");
    snprintf(s->buffer, sizeof(s->buffer),
             "CONNECT %s HTTP/1.1\r\n"
             "Host: %s\r\n"
             "Connection: close\r\n"
             "%s%s"
             "\r\n",
             path,
             hoststr,
             authstr ? "Proxy-" : "", authstr ? authstr : "");
    av_freep(&authstr);

    if ((ret = ffurl_write(s->hd, s->buffer, strlen(s->buffer))) < 0)
        goto fail;

    s->buf_ptr = s->buffer;
    s->buf_end = s->buffer;
    s->line_count = 0;
    s->filesize = -1;
    cur_auth_type = s->proxy_auth_state.auth_type;

    for (;;) {
        int new_loc;
        // Note: This uses buffering, potentially reading more than the
        // HTTP header. If tunneling a protocol where the server starts
        // the conversation, we might buffer part of that here, too.
        // Reading that requires using the proper ffurl_read() function
        // on this URLContext, not using the fd directly (as the tls
        // protocol does). This shouldn't be an issue for tls though,
        // since the client starts the conversation there, so there
        // is no extra data that we might buffer up here.
        if (http_get_line(s, line, sizeof(line)) < 0) {
            ret = AVERROR(EIO);
            goto fail;
        }

        av_dlog(h, "header='%s'\n", line);

        ret = process_line(h, line, s->line_count, &new_loc);
        if (ret < 0)
            goto fail;
        if (ret == 0)
            break;
        s->line_count++;
    }
    if (s->http_code == 407 && cur_auth_type == HTTP_AUTH_NONE &&
        s->proxy_auth_state.auth_type != HTTP_AUTH_NONE) {
        ffurl_close(s->hd);
        s->hd = NULL;
        goto redo;
    }

    if (s->http_code < 400)
        return 0;
    ret = AVERROR(EIO);

fail:
    http_proxy_close(h);
    return ret;
}

static int http_proxy_write(URLContext *h, const uint8_t *buf, int size)
{
    HTTPContext *s = h->priv_data;
    return ffurl_write(s->hd, buf, size);
}

URLProtocol ff_httpproxy_protocol = {
    .name                = "httpproxy",
    .url_open            = http_proxy_open,
    .url_read            = http_buf_read,
    .url_write           = http_proxy_write,
    .url_close           = http_proxy_close,
    .url_get_file_handle = http_get_file_handle,
    .priv_data_size      = sizeof(HTTPContext),
    .flags               = URL_PROTOCOL_FLAG_NETWORK,
};
#endif