http.c

/*
 * HTTP protocol for ffmpeg client
 * Copyright (c) 2000, 2001 Fabrice Bellard
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg 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.
 *
 * FFmpeg 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 FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "config.h"

#if CONFIG_ZLIB
#include <zlib.h>
#endif /* CONFIG_ZLIB */

#include "libavutil/avassert.h"
#include "libavutil/avstring.h"
#include "libavutil/opt.h"
#include "libavutil/time.h"
#include "libavutil/parseutils.h"

#include "avformat.h"
#include "http.h"
#include "httpauth.h"
#include "internal.h"
#include "network.h"
#include "os_support.h"
#include "url.h"

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

/* The IO buffer size is unrelated to the max URL size in itself, but needs
 * to be large enough to fit the full request headers (including long
 * path names). */
#define BUFFER_SIZE   MAX_URL_SIZE
#define MAX_REDIRECTS 8
#define HTTP_SINGLE   1
#define HTTP_MUTLI    2
#define MAX_EXPIRY    19
#define WHITESPACES " \n\t\r"
typedef enum {
    LOWER_PROTO,
    READ_HEADERS,
    WRITE_REPLY_HEADERS,
    FINISH
}HandshakeState;

typedef struct HTTPContext {
    const AVClass *class;
    URLContext *hd;
    unsigned char buffer[BUFFER_SIZE], *buf_ptr, *buf_end;
    int line_count;
    int http_code;
    /* Used if "Transfer-Encoding: chunked" otherwise -1. */
    uint64_t chunksize;
    int chunkend;
    uint64_t off, end_off, filesize;
    char *location;
    HTTPAuthState auth_state;
    HTTPAuthState proxy_auth_state;
    char *http_proxy;
    char *headers;
    char *mime_type;
    char *user_agent;
#if FF_API_HTTP_USER_AGENT
    char *user_agent_deprecated;
#endif
    char *content_type;
    /* Set if the server correctly handles Connection: close and will close
     * the connection after feeding us the content. */
    int willclose;
    int seekable;           /**< Control seekability, 0 = disable, 1 = enable, -1 = probe. */
    int chunked_post;
    /* A flag which indicates if the end of chunked encoding has been sent. */
    int end_chunked_post;
    /* A flag which indicates we have finished to read POST reply. */
    int end_header;
    /* A flag which indicates if we use persistent connections. */
    int multiple_requests;
    uint8_t *post_data;
    int post_datalen;
    int is_akamai;
    int is_mediagateway;
    char *cookies;          ///< holds newline (\n) delimited Set-Cookie header field values (without the "Set-Cookie: " field name)
    /* A dictionary containing cookies keyed by cookie name */
    AVDictionary *cookie_dict;
    int icy;
    /* how much data was read since the last ICY metadata packet */
    uint64_t icy_data_read;
    /* after how many bytes of read data a new metadata packet will be found */
    uint64_t icy_metaint;
    char *icy_metadata_headers;
    char *icy_metadata_packet;
    AVDictionary *metadata;
#if CONFIG_ZLIB
    int compressed;
    z_stream inflate_stream;
    uint8_t *inflate_buffer;
#endif /* CONFIG_ZLIB */
    AVDictionary *chained_options;
    int send_expect_100;
    char *method;
    int reconnect;
    int reconnect_at_eof;
    int reconnect_streamed;
    int reconnect_delay;
    int reconnect_delay_max;
    int listen;
    char *resource;
    int reply_code;
    int is_multi_client;
    HandshakeState handshake_step;
    int is_connected_server;
} HTTPContext;

#define OFFSET(x) offsetof(HTTPContext, x)
#define D AV_OPT_FLAG_DECODING_PARAM
#define E AV_OPT_FLAG_ENCODING_PARAM
#define DEFAULT_USER_AGENT "Lavf/" AV_STRINGIFY(LIBAVFORMAT_VERSION)

static const AVOption options[] = {
    { "seekable", "control seekability of connection", OFFSET(seekable), AV_OPT_TYPE_BOOL, { .i64 = -1 }, -1, 1, D },
    { "chunked_post", "use chunked transfer-encoding for posts", OFFSET(chunked_post), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, E },
    { "http_proxy", "set HTTP proxy to tunnel through", OFFSET(http_proxy), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D | E },
    { "headers", "set custom HTTP headers, can override built in default headers", OFFSET(headers), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D | E },
    { "content_type", "set a specific content type for the POST messages", OFFSET(content_type), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D | E },
    { "user_agent", "override User-Agent header", OFFSET(user_agent), AV_OPT_TYPE_STRING, { .str = DEFAULT_USER_AGENT }, 0, 0, D },
#if FF_API_HTTP_USER_AGENT
    { "user-agent", "override User-Agent header", OFFSET(user_agent_deprecated), AV_OPT_TYPE_STRING, { .str = DEFAULT_USER_AGENT }, 0, 0, D },
#endif
    { "multiple_requests", "use persistent connections", OFFSET(multiple_requests), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, D | E },
    { "post_data", "set custom HTTP post data", OFFSET(post_data), AV_OPT_TYPE_BINARY, .flags = D | E },
    { "mime_type", "export the MIME type", OFFSET(mime_type), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, AV_OPT_FLAG_EXPORT | AV_OPT_FLAG_READONLY },
    { "cookies", "set cookies to be sent in applicable future requests, use newline delimited Set-Cookie HTTP field value syntax", OFFSET(cookies), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D },
    { "icy", "request ICY metadata", OFFSET(icy), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, D },
    { "icy_metadata_headers", "return ICY metadata headers", OFFSET(icy_metadata_headers), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, AV_OPT_FLAG_EXPORT },
    { "icy_metadata_packet", "return current ICY metadata packet", OFFSET(icy_metadata_packet), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, AV_OPT_FLAG_EXPORT },
    { "metadata", "metadata read from the bitstream", OFFSET(metadata), AV_OPT_TYPE_DICT, {0}, 0, 0, AV_OPT_FLAG_EXPORT },
    { "auth_type", "HTTP authentication type", OFFSET(auth_state.auth_type), AV_OPT_TYPE_INT, { .i64 = HTTP_AUTH_NONE }, HTTP_AUTH_NONE, HTTP_AUTH_BASIC, D | E, "auth_type"},
    { "none", "No auth method set, autodetect", 0, AV_OPT_TYPE_CONST, { .i64 = HTTP_AUTH_NONE }, 0, 0, D | E, "auth_type"},
    { "basic", "HTTP basic authentication", 0, AV_OPT_TYPE_CONST, { .i64 = HTTP_AUTH_BASIC }, 0, 0, D | E, "auth_type"},
    { "send_expect_100", "Force sending an Expect: 100-continue header for POST", OFFSET(send_expect_100), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, E },
    { "location", "The actual location of the data received", OFFSET(location), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D | E },
    { "offset", "initial byte offset", OFFSET(off), AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT64_MAX, D },
    { "end_offset", "try to limit the request to bytes preceding this offset", OFFSET(end_off), AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT64_MAX, D },
    { "method", "Override the HTTP method or set the expected HTTP method from a client", OFFSET(method), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D | E },
    { "reconnect", "auto reconnect after disconnect before EOF", OFFSET(reconnect), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, D },
    { "reconnect_at_eof", "auto reconnect at EOF", OFFSET(reconnect_at_eof), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, D },
    { "reconnect_streamed", "auto reconnect streamed / non seekable streams", OFFSET(reconnect_streamed), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, D },
    { "reconnect_delay_max", "max reconnect delay in seconds after which to give up", OFFSET(reconnect_delay_max), AV_OPT_TYPE_INT, { .i64 = 120 }, 0, UINT_MAX/1000/1000, D },
    { "listen", "listen on HTTP", OFFSET(listen), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 2, D | E },
    { "resource", "The resource requested by a client", OFFSET(resource), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, E },
    { "reply_code", "The http status code to return to a client", OFFSET(reply_code), AV_OPT_TYPE_INT, { .i64 = 200}, INT_MIN, 599, E},
    { NULL }
};

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);
static int http_read_header(URLContext *h, int *new_location);
static int http_shutdown(URLContext *h, int flags);

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));
}

static int http_open_cnx_internal(URLContext *h, AVDictionary **options)
{
    const char *path, *proxy_path, *lower_proto = "tcp", *local_path;
    char hostname[1024], hoststr[1024], proto[10];
    char auth[1024], proxyauth[1024] = "";
    char path1[MAX_URL_SIZE];
    char buf[1024], urlbuf[MAX_URL_SIZE];
    int port, use_proxy, err, location_changed = 0;
    HTTPContext *s = h->priv_data;

    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);

    proxy_path = s->http_proxy ? s->http_proxy : getenv("http_proxy");
    use_proxy  = !ff_http_match_no_proxy(getenv("no_proxy"), hostname) &&
                 proxy_path && av_strstart(proxy_path, "http://", 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);

    if (!s->hd) {
        err = ffurl_open_whitelist(&s->hd, buf, AVIO_FLAG_READ_WRITE,
                                   &h->interrupt_callback, options,
                                   h->protocol_whitelist, h->protocol_blacklist, h);
        if (err < 0)
            return err;
    }

    err = http_connect(h, path, local_path, hoststr,
                       auth, proxyauth, &location_changed);
    if (err < 0)
        return err;

    return location_changed;
}

/* return non zero if error */
static int http_open_cnx(URLContext *h, AVDictionary **options)
{
    HTTPAuthType cur_auth_type, cur_proxy_auth_type;
    HTTPContext *s = h->priv_data;
    int location_changed, attempts = 0, redirects = 0;
redo:
    av_dict_copy(options, s->chained_options, 0);

    cur_auth_type       = s->auth_state.auth_type;
    cur_proxy_auth_type = s->auth_state.auth_type;

    location_changed = http_open_cnx_internal(h, options);
    if (location_changed < 0)
        goto fail;

    attempts++;
    if (s->http_code == 401) {
        if ((cur_auth_type == HTTP_AUTH_NONE || s->auth_state.stale) &&
            s->auth_state.auth_type != HTTP_AUTH_NONE && attempts < 4) {
            ffurl_closep(&s->hd);
            goto redo;
        } else
            goto fail;
    }
    if (s->http_code == 407) {
        if ((cur_proxy_auth_type == HTTP_AUTH_NONE || s->proxy_auth_state.stale) &&
            s->proxy_auth_state.auth_type != HTTP_AUTH_NONE && attempts < 4) {
            ffurl_closep(&s->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_closep(&s->hd);
        if (redirects++ >= MAX_REDIRECTS)
            return AVERROR(EIO);
        /* Restart the authentication process with the new target, which
         * might use a different auth mechanism. */
        memset(&s->auth_state, 0, sizeof(s->auth_state));
        attempts         = 0;
        location_changed = 0;
        goto redo;
    }
    return 0;

fail:
    if (s->hd)
        ffurl_closep(&s->hd);
    if (location_changed < 0)
        return location_changed;
    return ff_http_averror(s->http_code, AVERROR(EIO));
}

int ff_http_do_new_request(URLContext *h, const char *uri)
{
    HTTPContext *s = h->priv_data;
    AVDictionary *options = NULL;
    int ret;
    char hostname1[1024], hostname2[1024], proto1[10], proto2[10];
    int port1, port2;

    av_url_split(proto1, sizeof(proto1), NULL, 0,
                 hostname1, sizeof(hostname1), &port1,
                 NULL, 0, s->location);
    av_url_split(proto2, sizeof(proto2), NULL, 0,
                 hostname2, sizeof(hostname2), &port2,
                 NULL, 0, uri);
    if (port1 != port2 || strncmp(hostname1, hostname2, sizeof(hostname2)) != 0) {
        av_log(h, AV_LOG_ERROR, "Cannot reuse HTTP connection for different host: %s:%d != %s:%d\n",
            hostname1, port1,
            hostname2, port2
        );
        return AVERROR(EINVAL);
    }

    ret = http_shutdown(h, h->flags);
    if (ret < 0)
        return ret;

    s->end_chunked_post = 0;
    s->chunkend      = 0;
    s->off           = 0;
    s->icy_data_read = 0;
    av_free(s->location);
    s->location = av_strdup(uri);
    if (!s->location)
        return AVERROR(ENOMEM);

    ret = http_open_cnx(h, &options);
    av_dict_free(&options);
    return ret;
}

int ff_http_averror(int status_code, int default_averror)
{
    switch (status_code) {
        case 400: return AVERROR_HTTP_BAD_REQUEST;
        case 401: return AVERROR_HTTP_UNAUTHORIZED;
        case 403: return AVERROR_HTTP_FORBIDDEN;
        case 404: return AVERROR_HTTP_NOT_FOUND;
        default: break;
    }
    if (status_code >= 400 && status_code <= 499)
        return AVERROR_HTTP_OTHER_4XX;
    else if (status_code >= 500)
        return AVERROR_HTTP_SERVER_ERROR;
    else
        return default_averror;
}

static int http_write_reply(URLContext* h, int status_code)
{
    int ret, body = 0, reply_code, message_len;
    const char *reply_text, *content_type;
    HTTPContext *s = h->priv_data;
    char message[BUFFER_SIZE];
    content_type = "text/plain";

    if (status_code < 0)
        body = 1;
    switch (status_code) {
    case AVERROR_HTTP_BAD_REQUEST:
    case 400:
        reply_code = 400;
        reply_text = "Bad Request";
        break;
    case AVERROR_HTTP_FORBIDDEN:
    case 403:
        reply_code = 403;
        reply_text = "Forbidden";
        break;
    case AVERROR_HTTP_NOT_FOUND:
    case 404:
        reply_code = 404;
        reply_text = "Not Found";
        break;
    case 200:
        reply_code = 200;
        reply_text = "OK";
        content_type = s->content_type ? s->content_type : "application/octet-stream";
        break;
    case AVERROR_HTTP_SERVER_ERROR:
    case 500:
        reply_code = 500;
        reply_text = "Internal server error";
        break;
    default:
        return AVERROR(EINVAL);
    }
    if (body) {
        s->chunked_post = 0;
        message_len = snprintf(message, sizeof(message),
                 "HTTP/1.1 %03d %s\r\n"
                 "Content-Type: %s\r\n"
                 "Content-Length: %"SIZE_SPECIFIER"\r\n"
                 "%s"
                 "\r\n"
                 "%03d %s\r\n",
                 reply_code,
                 reply_text,
                 content_type,
                 strlen(reply_text) + 6, // 3 digit status code + space + \r\n
                 s->headers ? s->headers : "",
                 reply_code,
                 reply_text);
    } else {
        s->chunked_post = 1;
        message_len = snprintf(message, sizeof(message),
                 "HTTP/1.1 %03d %s\r\n"
                 "Content-Type: %s\r\n"
                 "Transfer-Encoding: chunked\r\n"
                 "%s"
                 "\r\n",
                 reply_code,
                 reply_text,
                 content_type,
                 s->headers ? s->headers : "");
    }
    av_log(h, AV_LOG_TRACE, "HTTP reply header: \n%s----\n", message);
    if ((ret = ffurl_write(s->hd, message, message_len)) < 0)
        return ret;
    return 0;
}

static void handle_http_errors(URLContext *h, int error)
{
    av_assert0(error < 0);
    http_write_reply(h, error);
}

static int http_handshake(URLContext *c)
{
    int ret, err, new_location;
    HTTPContext *ch = c->priv_data;
    URLContext *cl = ch->hd;
    switch (ch->handshake_step) {
    case LOWER_PROTO:
        av_log(c, AV_LOG_TRACE, "Lower protocol\n");
        if ((ret = ffurl_handshake(cl)) > 0)
            return 2 + ret;
        if (ret < 0)
            return ret;
        ch->handshake_step = READ_HEADERS;
        ch->is_connected_server = 1;
        return 2;
    case READ_HEADERS:
        av_log(c, AV_LOG_TRACE, "Read headers\n");
        if ((err = http_read_header(c, &new_location)) < 0) {
            handle_http_errors(c, err);
            return err;
        }
        ch->handshake_step = WRITE_REPLY_HEADERS;
        return 1;
    case WRITE_REPLY_HEADERS:
        av_log(c, AV_LOG_TRACE, "Reply code: %d\n", ch->reply_code);
        if ((err = http_write_reply(c, ch->reply_code)) < 0)
            return err;
        ch->handshake_step = FINISH;
        return 1;
    case FINISH:
        return 0;
    }
    // this should never be reached.
    return AVERROR(EINVAL);
}

static int http_listen(URLContext *h, const char *uri, int flags,
                       AVDictionary **options) {
    HTTPContext *s = h->priv_data;
    int ret;
    char hostname[1024], proto[10];
    char lower_url[100];
    const char *lower_proto = "tcp";
    int port;
    av_url_split(proto, sizeof(proto), NULL, 0, hostname, sizeof(hostname), &port,
                 NULL, 0, uri);
    if (!strcmp(proto, "https"))
        lower_proto = "tls";
    ff_url_join(lower_url, sizeof(lower_url), lower_proto, NULL, hostname, port,
                NULL);
    if ((ret = av_dict_set_int(options, "listen", s->listen, 0)) < 0)
        goto fail;
    if ((ret = ffurl_open_whitelist(&s->hd, lower_url, AVIO_FLAG_READ_WRITE,
                                    &h->interrupt_callback, options,
                                    h->protocol_whitelist, h->protocol_blacklist, h
                                   )) < 0)
        goto fail;
    s->handshake_step = LOWER_PROTO;
    if (s->listen == HTTP_SINGLE) { /* single client */
        s->reply_code = 200;
        while ((ret = http_handshake(h)) > 0);
    }
fail:
    av_dict_free(&s->chained_options);
    return ret;
}

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

    if( s->seekable == 1 )
        h->is_streamed = 0;
    else
        h->is_streamed = 1;

    s->filesize = UINT64_MAX;
    s->location = av_strdup(uri);
    if (!s->location)
        return AVERROR(ENOMEM);
    if (options)
        av_dict_copy(&s->chained_options, *options, 0);

    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");
            ret = av_reallocp(&s->headers, len + 3);
            if (ret < 0)
                return ret;
            s->headers[len]     = '\r';
            s->headers[len + 1] = '\n';
            s->headers[len + 2] = '\0';
        }
    }

    if (s->listen) {
        return http_listen(h, uri, flags, options);
    }
    ret = http_open_cnx(h, options);
    if (ret < 0)
        av_dict_free(&s->chained_options);
    return ret;
}

static int http_accept(URLContext *s, URLContext **c)
{
    int ret;
    HTTPContext *sc = s->priv_data;
    HTTPContext *cc;
    URLContext *sl = sc->hd;
    URLContext *cl = NULL;

    av_assert0(sc->listen);
    if ((ret = ffurl_alloc(c, s->filename, s->flags, &sl->interrupt_callback)) < 0)
        goto fail;
    cc = (*c)->priv_data;
    if ((ret = ffurl_accept(sl, &cl)) < 0)
        goto fail;
    cc->hd = cl;
    cc->is_multi_client = 1;
fail:
    return ret;
}

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 len;
        } else if (len == 0) {
            return AVERROR_EOF;
        } 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 ch;
        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 check_http_code(URLContext *h, int http_code, const char *end)
{
    HTTPContext *s = h->priv_data;
    /* error codes are 4xx and 5xx, but regard 401 as a success, so we
     * don't abort until all headers have been parsed. */
    if (http_code >= 400 && http_code < 600 &&
        (http_code != 401 || s->auth_state.auth_type != HTTP_AUTH_NONE) &&
        (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", http_code, end);
        return ff_http_averror(http_code, AVERROR(EIO));
    }
    return 0;
}

static int parse_location(HTTPContext *s, const char *p)
{
    char redirected_location[MAX_URL_SIZE], *new_loc;
    ff_make_absolute_url(redirected_location, sizeof(redirected_location),
                         s->location, p);
    new_loc = av_strdup(redirected_location);
    if (!new_loc)
        return AVERROR(ENOMEM);
    av_free(s->location);
    s->location = new_loc;
    return 0;
}

/* "bytes $from-$to/$document_size" */
static void parse_content_range(URLContext *h, const char *p)
{
    HTTPContext *s = h->priv_data;
    const char *slash;

    if (!strncmp(p, "bytes ", 6)) {
        p     += 6;
        s->off = strtoull(p, NULL, 10);
        if ((slash = strchr(p, '/')) && strlen(slash) > 0)
            s->filesize = strtoull(slash + 1, NULL, 10);
    }
    if (s->seekable == -1 && (!s->is_akamai || s->filesize != 2147483647))
        h->is_streamed = 0; /* we _can_ in fact seek */
}

static int parse_content_encoding(URLContext *h, const char *p)
{
    if (!av_strncasecmp(p, "gzip", 4) ||
        !av_strncasecmp(p, "deflate", 7)) {
#if CONFIG_ZLIB
        HTTPContext *s = h->priv_data;

        s->compressed = 1;
        inflateEnd(&s->inflate_stream);
        if (inflateInit2(&s->inflate_stream, 32 + 15) != Z_OK) {
            av_log(h, AV_LOG_WARNING, "Error during zlib initialisation: %s\n",
                   s->inflate_stream.msg);
            return AVERROR(ENOSYS);
        }
        if (zlibCompileFlags() & (1 << 17)) {
            av_log(h, AV_LOG_WARNING,
                   "Your zlib was compiled without gzip support.\n");
            return AVERROR(ENOSYS);
        }
#else
        av_log(h, AV_LOG_WARNING,
               "Compressed (%s) content, need zlib with gzip support\n", p);
        return AVERROR(ENOSYS);
#endif /* CONFIG_ZLIB */
    } else if (!av_strncasecmp(p, "identity", 8)) {
        // The normal, no-encoding case (although servers shouldn't include
        // the header at all if this is the case).
    } else {
        av_log(h, AV_LOG_WARNING, "Unknown content coding: %s\n", p);
    }
    return 0;
}

// Concat all Icy- header lines
static int parse_icy(HTTPContext *s, const char *tag, const char *p)
{
    int len = 4 + strlen(p) + strlen(tag);
    int is_first = !s->icy_metadata_headers;
    int ret;

    av_dict_set(&s->metadata, tag, p, 0);

    if (s->icy_metadata_headers)
        len += strlen(s->icy_metadata_headers);

    if ((ret = av_reallocp(&s->icy_metadata_headers, len)) < 0)
        return ret;

    if (is_first)
        *s->icy_metadata_headers = '\0';

    av_strlcatf(s->icy_metadata_headers, len, "%s: %s\n", tag, p);

    return 0;
}

static int parse_set_cookie_expiry_time(const char *exp_str, struct tm *buf)
{
    char exp_buf[MAX_EXPIRY];
    int i, j, exp_buf_len = MAX_EXPIRY-1;
    char *expiry;

    // strip off any punctuation or whitespace
    for (i = 0, j = 0; exp_str[i] != '\0' && j < exp_buf_len; i++) {
        if ((exp_str[i] >= '0' && exp_str[i] <= '9') ||
            (exp_str[i] >= 'A' && exp_str[i] <= 'Z') ||
            (exp_str[i] >= 'a' && exp_str[i] <= 'z')) {
            exp_buf[j] = exp_str[i];
            j++;
        }
    }
    exp_buf[j] = '\0';
    expiry = exp_buf;

    // move the string beyond the day of week
    while ((*expiry < '0' || *expiry > '9') && *expiry != '\0')
        expiry++;

    return av_small_strptime(expiry, "%d%b%Y%H%M%S", buf) ? 0 : AVERROR(EINVAL);
}

static int parse_set_cookie(const char *set_cookie, AVDictionary **dict)
{
    char *param, *next_param, *cstr, *back;

    if (!(cstr = av_strdup(set_cookie)))
        return AVERROR(EINVAL);

    // strip any trailing whitespace
    back = &cstr[strlen(cstr)-1];
    while (strchr(WHITESPACES, *back)) {
        *back='\0';
        back--;
    }

    next_param = cstr;
    while ((param = av_strtok(next_param, ";", &next_param))) {
        char *name, *value;
        param += strspn(param, WHITESPACES);
        if ((name = av_strtok(param, "=", &value))) {
            if (av_dict_set(dict, name, value, 0) < 0) {
                av_free(cstr);
                return -1;
            }
        }
    }

    av_free(cstr);
    return 0;
}

static int parse_cookie(HTTPContext *s, const char *p, AVDictionary **cookies)
{
    AVDictionary *new_params = NULL;
    AVDictionaryEntry *e, *cookie_entry;
    char *eql, *name;

    // ensure the cookie is parsable
    if (parse_set_cookie(p, &new_params))
        return -1;

    // if there is no cookie value there is nothing to parse
    cookie_entry = av_dict_get(new_params, "", NULL, AV_DICT_IGNORE_SUFFIX);
    if (!cookie_entry || !cookie_entry->value) {
        av_dict_free(&new_params);
        return -1;
    }

    // ensure the cookie is not expired or older than an existing value
    if ((e = av_dict_get(new_params, "expires", NULL, 0)) && e->value) {
        struct tm new_tm = {0};
        if (!parse_set_cookie_expiry_time(e->value, &new_tm)) {
            AVDictionaryEntry *e2;

            // if the cookie has already expired ignore it
            if (av_timegm(&new_tm) < av_gettime() / 1000000) {
                av_dict_free(&new_params);
                return -1;
            }

            // only replace an older cookie with the same name
            e2 = av_dict_get(*cookies, cookie_entry->key, NULL, 0);
            if (e2 && e2->value) {
                AVDictionary *old_params = NULL;
                if (!parse_set_cookie(p, &old_params)) {
                    e2 = av_dict_get(old_params, "expires", NULL, 0);
                    if (e2 && e2->value) {
                        struct tm old_tm = {0};
                        if (!parse_set_cookie_expiry_time(e->value, &old_tm)) {
                            if (av_timegm(&new_tm) < av_timegm(&old_tm)) {
                                av_dict_free(&new_params);
                                av_dict_free(&old_params);
                                return -1;
                            }
                        }
                    }
                }
                av_dict_free(&old_params);
            }
        }
    }

    // duplicate the cookie name (dict will dupe the value)
    if (!(eql = strchr(p, '='))) return AVERROR(EINVAL);
    if (!(name = av_strndup(p, eql - p))) return AVERROR(ENOMEM);

    // add the cookie to the dictionary
    av_dict_set(cookies, name, eql, AV_DICT_DONT_STRDUP_KEY);

    return 0;
}

static int cookie_string(AVDictionary *dict, char **cookies)
{
    AVDictionaryEntry *e = NULL;
    int len = 1;

    // determine how much memory is needed for the cookies string
    while (e = av_dict_get(dict, "", e, AV_DICT_IGNORE_SUFFIX))
        len += strlen(e->key) + strlen(e->value) + 1;

    // reallocate the cookies
    e = NULL;
    if (*cookies) av_free(*cookies);
    *cookies = av_malloc(len);
    if (!*cookies) return AVERROR(ENOMEM);
    *cookies[0] = '\0';

    // write out the cookies
    while (e = av_dict_get(dict, "", e, AV_DICT_IGNORE_SUFFIX))
        av_strlcatf(*cookies, len, "%s%s\n", e->key, e->value);

    return 0;
}

static int process_line(URLContext *h, char *line, int line_count,
                        int *new_location)
{
    HTTPContext *s = h->priv_data;
    const char *auto_method =  h->flags & AVIO_FLAG_READ ? "POST" : "GET";
    char *tag, *p, *end, *method, *resource, *version;
    int ret;

    /* end of header */
    if (line[0] == '\0') {
        s->end_header = 1;
        return 0;
    }

    p = line;
    if (line_count == 0) {
        if (s->is_connected_server) {
            // HTTP method
            method = p;
            while (*p && !av_isspace(*p))
                p++;
            *(p++) = '\0';
            av_log(h, AV_LOG_TRACE, "Received method: %s\n", method);
            if (s->method) {
                if (av_strcasecmp(s->method, method)) {
                    av_log(h, AV_LOG_ERROR, "Received and expected HTTP method do not match. (%s expected, %s received)\n",
                           s->method, method);
                    return ff_http_averror(400, AVERROR(EIO));
                }
            } else {
                // use autodetected HTTP method to expect
                av_log(h, AV_LOG_TRACE, "Autodetected %s HTTP method\n", auto_method);
                if (av_strcasecmp(auto_method, method)) {
                    av_log(h, AV_LOG_ERROR, "Received and autodetected HTTP method did not match "
                           "(%s autodetected %s received)\n", auto_method, method);
                    return ff_http_averror(400, AVERROR(EIO));
                }
                if (!(s->method = av_strdup(method)))
                    return AVERROR(ENOMEM);
            }

            // HTTP resource
            while (av_isspace(*p))
                p++;
            resource = p;
            while (!av_isspace(*p))
                p++;
            *(p++) = '\0';
            av_log(h, AV_LOG_TRACE, "Requested resource: %s\n", resource);
            if (!(s->resource = av_strdup(resource)))
                return AVERROR(ENOMEM);

            // HTTP version
            while (av_isspace(*p))
                p++;
            version = p;
            while (*p && !av_isspace(*p))
                p++;
            *p = '\0';
            if (av_strncasecmp(version, "HTTP/", 5)) {
                av_log(h, AV_LOG_ERROR, "Malformed HTTP version string.\n");
                return ff_http_averror(400, AVERROR(EIO));
            }
            av_log(h, AV_LOG_TRACE, "HTTP version string: %s\n", version);
        } else {
            while (!av_isspace(*p) && *p != '\0')
                p++;
            while (av_isspace(*p))
                p++;
            s->http_code = strtol(p, &end, 10);

            av_log(h, AV_LOG_TRACE, "http_code=%d\n", s->http_code);

            if ((ret = check_http_code(h, s->http_code, end)) < 0)
                return ret;
        }
    } else {
        while (*p != '\0' && *p != ':')
            p++;
        if (*p != ':')
            return 1;

        *p  = '\0';
        tag = line;
        p++;
        while (av_isspace(*p))
            p++;
        if (!av_strcasecmp(tag, "Location")) {
            if ((ret = parse_location(s, p)) < 0)
                return ret;
            *new_location = 1;
        } else if (!av_strcasecmp(tag, "Content-Length") &&
                   s->filesize == UINT64_MAX) {
            s->filesize = strtoull(p, NULL, 10);
        } else if (!av_strcasecmp(tag, "Content-Range")) {
            parse_content_range(h, p);
        } else if (!av_strcasecmp(tag, "Accept-Ranges") &&
                   !strncmp(p, "bytes", 5) &&
                   s->seekable == -1) {
            h->is_streamed = 0;
        } else if (!av_strcasecmp(tag, "Transfer-Encoding") &&
                   !av_strncasecmp(p, "chunked", 7)) {
            s->filesize  = UINT64_MAX;
            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;
        } else if (!av_strcasecmp(tag, "Server")) {
            if (!av_strcasecmp(p, "AkamaiGHost")) {
                s->is_akamai = 1;
            } else if (!av_strncasecmp(p, "MediaGateway", 12)) {
                s->is_mediagateway = 1;
            }
        } else if (!av_strcasecmp(tag, "Content-Type")) {
            av_free(s->mime_type);
            s->mime_type = av_strdup(p);
        } else if (!av_strcasecmp(tag, "Set-Cookie")) {
            if (parse_cookie(s, p, &s->cookie_dict))
                av_log(h, AV_LOG_WARNING, "Unable to parse '%s'\n", p);
        } else if (!av_strcasecmp(tag, "Icy-MetaInt")) {
            s->icy_metaint = strtoull(p, NULL, 10);
        } else if (!av_strncasecmp(tag, "Icy-", 4)) {
            if ((ret = parse_icy(s, tag, p)) < 0)
                return ret;
        } else if (!av_strcasecmp(tag, "Content-Encoding")) {
            if ((ret = parse_content_encoding(h, p)) < 0)
                return ret;
        }
    }
    return 1;
}

/**
 * Create a string containing cookie values for use as a HTTP cookie header
 * field value for a particular path and domain from the cookie values stored in
 * the HTTP protocol context. The cookie string is stored in *cookies.
 *
 * @return a negative value if an error condition occurred, 0 otherwise
 */
static int get_cookies(HTTPContext *s, char **cookies, const char *path,
                       const char *domain)
{
    // cookie strings will look like Set-Cookie header field values.  Multiple
    // Set-Cookie fields will result in multiple values delimited by a newline
    int ret = 0;
    char *cookie, *set_cookies = av_strdup(s->cookies), *next = set_cookies;