xref: /third_party/ffmpeg/libavformat/udp.c (revision cabdff1a)
1/*
2 * UDP prototype streaming system
3 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/**
23 * @file
24 * UDP protocol
25 */
26
27#define _DEFAULT_SOURCE
28#define _BSD_SOURCE     /* Needed for using struct ip_mreq with recent glibc */
29
30#include "avformat.h"
31#include "avio_internal.h"
32#include "libavutil/avassert.h"
33#include "libavutil/parseutils.h"
34#include "libavutil/fifo.h"
35#include "libavutil/intreadwrite.h"
36#include "libavutil/avstring.h"
37#include "libavutil/opt.h"
38#include "libavutil/log.h"
39#include "libavutil/time.h"
40#include "internal.h"
41#include "network.h"
42#include "os_support.h"
43#include "url.h"
44#include "ip.h"
45
46#ifdef __APPLE__
47#include "TargetConditionals.h"
48#endif
49
50#if HAVE_UDPLITE_H
51#include "udplite.h"
52#else
53/* On many Linux systems, udplite.h is missing but the kernel supports UDP-Lite.
54 * So, we provide a fallback here.
55 */
56#define UDPLITE_SEND_CSCOV                               10
57#define UDPLITE_RECV_CSCOV                               11
58#endif
59
60#ifndef IPPROTO_UDPLITE
61#define IPPROTO_UDPLITE                                  136
62#endif
63
64#if HAVE_W32THREADS
65#undef HAVE_PTHREAD_CANCEL
66#define HAVE_PTHREAD_CANCEL 1
67#endif
68
69#if HAVE_PTHREAD_CANCEL
70#include "libavutil/thread.h"
71#endif
72
73#ifndef IPV6_ADD_MEMBERSHIP
74#define IPV6_ADD_MEMBERSHIP IPV6_JOIN_GROUP
75#define IPV6_DROP_MEMBERSHIP IPV6_LEAVE_GROUP
76#endif
77
78#define UDP_TX_BUF_SIZE 32768
79#define UDP_RX_BUF_SIZE 393216
80#define UDP_MAX_PKT_SIZE 65536
81#define UDP_HEADER_SIZE 8
82
83typedef struct UDPContext {
84    const AVClass *class;
85    int udp_fd;
86    int ttl;
87    int udplite_coverage;
88    int buffer_size;
89    int pkt_size;
90    int is_multicast;
91    int is_broadcast;
92    int local_port;
93    int reuse_socket;
94    int overrun_nonfatal;
95    struct sockaddr_storage dest_addr;
96    int dest_addr_len;
97    int is_connected;
98
99    /* Circular Buffer variables for use in UDP receive code */
100    int circular_buffer_size;
101    AVFifo *fifo;
102    int circular_buffer_error;
103    int64_t bitrate; /* number of bits to send per second */
104    int64_t burst_bits;
105    int close_req;
106#if HAVE_PTHREAD_CANCEL
107    pthread_t circular_buffer_thread;
108    pthread_mutex_t mutex;
109    pthread_cond_t cond;
110    int thread_started;
111#endif
112    uint8_t tmp[UDP_MAX_PKT_SIZE+4];
113    int remaining_in_dg;
114    char *localaddr;
115    int timeout;
116    struct sockaddr_storage local_addr_storage;
117    char *sources;
118    char *block;
119    IPSourceFilters filters;
120} UDPContext;
121
122#define OFFSET(x) offsetof(UDPContext, x)
123#define D AV_OPT_FLAG_DECODING_PARAM
124#define E AV_OPT_FLAG_ENCODING_PARAM
125static const AVOption options[] = {
126    { "buffer_size",    "System data size (in bytes)",                     OFFSET(buffer_size),    AV_OPT_TYPE_INT,    { .i64 = -1 },    -1, INT_MAX, .flags = D|E },
127    { "bitrate",        "Bits to send per second",                         OFFSET(bitrate),        AV_OPT_TYPE_INT64,  { .i64 = 0  },     0, INT64_MAX, .flags = E },
128    { "burst_bits",     "Max length of bursts in bits (when using bitrate)", OFFSET(burst_bits),   AV_OPT_TYPE_INT64,  { .i64 = 0  },     0, INT64_MAX, .flags = E },
129    { "localport",      "Local port",                                      OFFSET(local_port),     AV_OPT_TYPE_INT,    { .i64 = -1 },    -1, INT_MAX, D|E },
130    { "local_port",     "Local port",                                      OFFSET(local_port),     AV_OPT_TYPE_INT,    { .i64 = -1 },    -1, INT_MAX, .flags = D|E },
131    { "localaddr",      "Local address",                                   OFFSET(localaddr),      AV_OPT_TYPE_STRING, { .str = NULL },               .flags = D|E },
132    { "udplite_coverage", "choose UDPLite head size which should be validated by checksum", OFFSET(udplite_coverage), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, D|E },
133    { "pkt_size",       "Maximum UDP packet size",                         OFFSET(pkt_size),       AV_OPT_TYPE_INT,    { .i64 = 1472 },  -1, INT_MAX, .flags = D|E },
134    { "reuse",          "explicitly allow reusing UDP sockets",            OFFSET(reuse_socket),   AV_OPT_TYPE_BOOL,   { .i64 = -1 },    -1, 1,       D|E },
135    { "reuse_socket",   "explicitly allow reusing UDP sockets",            OFFSET(reuse_socket),   AV_OPT_TYPE_BOOL,   { .i64 = -1 },    -1, 1,       .flags = D|E },
136    { "broadcast", "explicitly allow or disallow broadcast destination",   OFFSET(is_broadcast),   AV_OPT_TYPE_BOOL,   { .i64 = 0  },     0, 1,       E },
137    { "ttl",            "Time to live (multicast only)",                   OFFSET(ttl),            AV_OPT_TYPE_INT,    { .i64 = 16 },     0, 255,     E },
138    { "connect",        "set if connect() should be called on socket",     OFFSET(is_connected),   AV_OPT_TYPE_BOOL,   { .i64 =  0 },     0, 1,       .flags = D|E },
139    { "fifo_size",      "set the UDP receiving circular buffer size, expressed as a number of packets with size of 188 bytes", OFFSET(circular_buffer_size), AV_OPT_TYPE_INT, {.i64 = 7*4096}, 0, INT_MAX, D },
140    { "overrun_nonfatal", "survive in case of UDP receiving circular buffer overrun", OFFSET(overrun_nonfatal), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1,    D },
141    { "timeout",        "set raise error timeout, in microseconds (only in read mode)",OFFSET(timeout),         AV_OPT_TYPE_INT,  {.i64 = 0}, 0, INT_MAX, D },
142    { "sources",        "Source list",                                     OFFSET(sources),        AV_OPT_TYPE_STRING, { .str = NULL },               .flags = D|E },
143    { "block",          "Block list",                                      OFFSET(block),          AV_OPT_TYPE_STRING, { .str = NULL },               .flags = D|E },
144    { NULL }
145};
146
147static const AVClass udp_class = {
148    .class_name = "udp",
149    .item_name  = av_default_item_name,
150    .option     = options,
151    .version    = LIBAVUTIL_VERSION_INT,
152};
153
154static const AVClass udplite_context_class = {
155    .class_name     = "udplite",
156    .item_name      = av_default_item_name,
157    .option         = options,
158    .version        = LIBAVUTIL_VERSION_INT,
159};
160
161static int udp_set_multicast_ttl(int sockfd, int mcastTTL,
162                                 struct sockaddr *addr,
163                                 void *logctx)
164{
165    int protocol, cmd;
166
167    /* There is some confusion in the world whether IP_MULTICAST_TTL
168     * takes a byte or an int as an argument.
169     * BSD seems to indicate byte so we are going with that and use
170     * int and fall back to byte to be safe */
171    switch (addr->sa_family) {
172#ifdef IP_MULTICAST_TTL
173        case AF_INET:
174            protocol = IPPROTO_IP;
175            cmd      = IP_MULTICAST_TTL;
176            break;
177#endif
178#ifdef IPV6_MULTICAST_HOPS
179        case AF_INET6:
180            protocol = IPPROTO_IPV6;
181            cmd      = IPV6_MULTICAST_HOPS;
182            break;
183#endif
184        default:
185            return 0;
186    }
187
188    if (setsockopt(sockfd, protocol, cmd, &mcastTTL, sizeof(mcastTTL)) < 0) {
189        /* BSD compatibility */
190        unsigned char ttl = (unsigned char) mcastTTL;
191
192        ff_log_net_error(logctx, AV_LOG_DEBUG, "setsockopt(IPV4/IPV6 MULTICAST TTL)");
193        if (setsockopt(sockfd, protocol, cmd, &ttl, sizeof(ttl)) < 0) {
194            ff_log_net_error(logctx, AV_LOG_ERROR, "setsockopt(IPV4/IPV6 MULTICAST TTL)");
195            return ff_neterrno();
196        }
197    }
198
199    return 0;
200}
201
202static int udp_join_multicast_group(int sockfd, struct sockaddr *addr,
203                                    struct sockaddr *local_addr, void *logctx)
204{
205#ifdef IP_ADD_MEMBERSHIP
206    if (addr->sa_family == AF_INET) {
207        struct ip_mreq mreq;
208
209        mreq.imr_multiaddr.s_addr = ((struct sockaddr_in *)addr)->sin_addr.s_addr;
210        if (local_addr)
211            mreq.imr_interface= ((struct sockaddr_in *)local_addr)->sin_addr;
212        else
213            mreq.imr_interface.s_addr = INADDR_ANY;
214        if (setsockopt(sockfd, IPPROTO_IP, IP_ADD_MEMBERSHIP, (const void *)&mreq, sizeof(mreq)) < 0) {
215            ff_log_net_error(logctx, AV_LOG_ERROR, "setsockopt(IP_ADD_MEMBERSHIP)");
216            return ff_neterrno();
217        }
218    }
219#endif
220#if HAVE_STRUCT_IPV6_MREQ && defined(IPPROTO_IPV6)
221    if (addr->sa_family == AF_INET6) {
222        struct ipv6_mreq mreq6;
223
224        memcpy(&mreq6.ipv6mr_multiaddr, &(((struct sockaddr_in6 *)addr)->sin6_addr), sizeof(struct in6_addr));
225        //TODO: Interface index should be looked up from local_addr
226        mreq6.ipv6mr_interface = 0;
227        if (setsockopt(sockfd, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, &mreq6, sizeof(mreq6)) < 0) {
228            ff_log_net_error(logctx, AV_LOG_ERROR, "setsockopt(IPV6_ADD_MEMBERSHIP)");
229            return ff_neterrno();
230        }
231    }
232#endif
233    return 0;
234}
235
236static int udp_leave_multicast_group(int sockfd, struct sockaddr *addr,
237                                     struct sockaddr *local_addr, void *logctx)
238{
239#ifdef IP_DROP_MEMBERSHIP
240    if (addr->sa_family == AF_INET) {
241        struct ip_mreq mreq;
242
243        mreq.imr_multiaddr.s_addr = ((struct sockaddr_in *)addr)->sin_addr.s_addr;
244        if (local_addr)
245            mreq.imr_interface = ((struct sockaddr_in *)local_addr)->sin_addr;
246        else
247            mreq.imr_interface.s_addr = INADDR_ANY;
248        if (setsockopt(sockfd, IPPROTO_IP, IP_DROP_MEMBERSHIP, (const void *)&mreq, sizeof(mreq)) < 0) {
249            ff_log_net_error(logctx, AV_LOG_ERROR, "setsockopt(IP_DROP_MEMBERSHIP)");
250            return -1;
251        }
252    }
253#endif
254#if HAVE_STRUCT_IPV6_MREQ && defined(IPPROTO_IPV6)
255    if (addr->sa_family == AF_INET6) {
256        struct ipv6_mreq mreq6;
257
258        memcpy(&mreq6.ipv6mr_multiaddr, &(((struct sockaddr_in6 *)addr)->sin6_addr), sizeof(struct in6_addr));
259        //TODO: Interface index should be looked up from local_addr
260        mreq6.ipv6mr_interface = 0;
261        if (setsockopt(sockfd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, &mreq6, sizeof(mreq6)) < 0) {
262            ff_log_net_error(logctx, AV_LOG_ERROR, "setsockopt(IPV6_DROP_MEMBERSHIP)");
263            return -1;
264        }
265    }
266#endif
267    return 0;
268}
269
270static int udp_set_multicast_sources(URLContext *h,
271                                     int sockfd, struct sockaddr *addr,
272                                     int addr_len, struct sockaddr_storage *local_addr,
273                                     struct sockaddr_storage *sources,
274                                     int nb_sources, int include)
275{
276    int i;
277    if (addr->sa_family != AF_INET) {
278#if HAVE_STRUCT_GROUP_SOURCE_REQ && defined(MCAST_BLOCK_SOURCE)
279        /* For IPv4 prefer the old approach, as that alone works reliably on
280         * Windows and it also supports supplying the interface based on its
281         * address. */
282        int i;
283        for (i = 0; i < nb_sources; i++) {
284            struct group_source_req mreqs;
285            int level = addr->sa_family == AF_INET ? IPPROTO_IP : IPPROTO_IPV6;
286
287            //TODO: Interface index should be looked up from local_addr
288            mreqs.gsr_interface = 0;
289            memcpy(&mreqs.gsr_group, addr, addr_len);
290            memcpy(&mreqs.gsr_source, &sources[i], sizeof(*sources));
291
292            if (setsockopt(sockfd, level,
293                           include ? MCAST_JOIN_SOURCE_GROUP : MCAST_BLOCK_SOURCE,
294                           (const void *)&mreqs, sizeof(mreqs)) < 0) {
295                if (include)
296                    ff_log_net_error(h, AV_LOG_ERROR, "setsockopt(MCAST_JOIN_SOURCE_GROUP)");
297                else
298                    ff_log_net_error(h, AV_LOG_ERROR, "setsockopt(MCAST_BLOCK_SOURCE)");
299                return ff_neterrno();
300            }
301        }
302        return 0;
303#else
304        av_log(h, AV_LOG_ERROR,
305               "Setting multicast sources only supported for IPv4\n");
306        return AVERROR(EINVAL);
307#endif
308    }
309#if HAVE_STRUCT_IP_MREQ_SOURCE && defined(IP_BLOCK_SOURCE)
310    for (i = 0; i < nb_sources; i++) {
311        struct ip_mreq_source mreqs;
312        if (sources[i].ss_family != AF_INET) {
313            av_log(h, AV_LOG_ERROR, "Source/block address %d is of incorrect protocol family\n", i + 1);
314            return AVERROR(EINVAL);
315        }
316
317        mreqs.imr_multiaddr.s_addr = ((struct sockaddr_in *)addr)->sin_addr.s_addr;
318        if (local_addr)
319            mreqs.imr_interface = ((struct sockaddr_in *)local_addr)->sin_addr;
320        else
321            mreqs.imr_interface.s_addr = INADDR_ANY;
322        mreqs.imr_sourceaddr.s_addr = ((struct sockaddr_in *)&sources[i])->sin_addr.s_addr;
323
324        if (setsockopt(sockfd, IPPROTO_IP,
325                       include ? IP_ADD_SOURCE_MEMBERSHIP : IP_BLOCK_SOURCE,
326                       (const void *)&mreqs, sizeof(mreqs)) < 0) {
327            if (include)
328                ff_log_net_error(h, AV_LOG_ERROR, "setsockopt(IP_ADD_SOURCE_MEMBERSHIP)");
329            else
330                ff_log_net_error(h, AV_LOG_ERROR, "setsockopt(IP_BLOCK_SOURCE)");
331            return ff_neterrno();
332        }
333    }
334#else
335    return AVERROR(ENOSYS);
336#endif
337    return 0;
338}
339static int udp_set_url(URLContext *h,
340                       struct sockaddr_storage *addr,
341                       const char *hostname, int port)
342{
343    struct addrinfo *res0;
344    int addr_len;
345
346    res0 = ff_ip_resolve_host(h, hostname, port, SOCK_DGRAM, AF_UNSPEC, 0);
347    if (!res0) return AVERROR(EIO);
348    memcpy(addr, res0->ai_addr, res0->ai_addrlen);
349    addr_len = res0->ai_addrlen;
350    freeaddrinfo(res0);
351
352    return addr_len;
353}
354
355static int udp_socket_create(URLContext *h, struct sockaddr_storage *addr,
356                             socklen_t *addr_len, const char *localaddr)
357{
358    UDPContext *s = h->priv_data;
359    int udp_fd = -1;
360    struct addrinfo *res0, *res;
361    int family = AF_UNSPEC;
362
363    if (((struct sockaddr *) &s->dest_addr)->sa_family)
364        family = ((struct sockaddr *) &s->dest_addr)->sa_family;
365    res0 = ff_ip_resolve_host(h, (localaddr && localaddr[0]) ? localaddr : NULL,
366                            s->local_port,
367                            SOCK_DGRAM, family, AI_PASSIVE);
368    if (!res0)
369        goto fail;
370    for (res = res0; res; res=res->ai_next) {
371        if (s->udplite_coverage)
372            udp_fd = ff_socket(res->ai_family, SOCK_DGRAM, IPPROTO_UDPLITE, h);
373        else
374            udp_fd = ff_socket(res->ai_family, SOCK_DGRAM, 0, h);
375        if (udp_fd != -1) break;
376        ff_log_net_error(h, AV_LOG_ERROR, "socket");
377    }
378
379    if (udp_fd < 0)
380        goto fail;
381
382    memcpy(addr, res->ai_addr, res->ai_addrlen);
383    *addr_len = res->ai_addrlen;
384
385    freeaddrinfo(res0);
386
387    return udp_fd;
388
389 fail:
390    if (udp_fd >= 0)
391        closesocket(udp_fd);
392    if(res0)
393        freeaddrinfo(res0);
394    return -1;
395}
396
397static int udp_port(struct sockaddr_storage *addr, int addr_len)
398{
399    char sbuf[sizeof(int)*3+1];
400    int error;
401
402    if ((error = getnameinfo((struct sockaddr *)addr, addr_len, NULL, 0,  sbuf, sizeof(sbuf), NI_NUMERICSERV)) != 0) {
403        av_log(NULL, AV_LOG_ERROR, "getnameinfo: %s\n", gai_strerror(error));
404        return -1;
405    }
406
407    return strtol(sbuf, NULL, 10);
408}
409
410
411/**
412 * If no filename is given to av_open_input_file because you want to
413 * get the local port first, then you must call this function to set
414 * the remote server address.
415 *
416 * url syntax: udp://host:port[?option=val...]
417 * option: 'ttl=n'       : set the ttl value (for multicast only)
418 *         'localport=n' : set the local port
419 *         'pkt_size=n'  : set max packet size
420 *         'reuse=1'     : enable reusing the socket
421 *         'overrun_nonfatal=1': survive in case of circular buffer overrun
422 *
423 * @param h media file context
424 * @param uri of the remote server
425 * @return zero if no error.
426 */
427int ff_udp_set_remote_url(URLContext *h, const char *uri)
428{
429    UDPContext *s = h->priv_data;
430    char hostname[256], buf[10];
431    int port;
432    const char *p;
433
434    av_url_split(NULL, 0, NULL, 0, hostname, sizeof(hostname), &port, NULL, 0, uri);
435
436    /* set the destination address */
437    s->dest_addr_len = udp_set_url(h, &s->dest_addr, hostname, port);
438    if (s->dest_addr_len < 0) {
439        return AVERROR(EIO);
440    }
441    s->is_multicast = ff_is_multicast_address((struct sockaddr*) &s->dest_addr);
442    p = strchr(uri, '?');
443    if (p) {
444        if (av_find_info_tag(buf, sizeof(buf), "connect", p)) {
445            int was_connected = s->is_connected;
446            s->is_connected = strtol(buf, NULL, 10);
447            if (s->is_connected && !was_connected) {
448                if (connect(s->udp_fd, (struct sockaddr *) &s->dest_addr,
449                            s->dest_addr_len)) {
450                    s->is_connected = 0;
451                    ff_log_net_error(h, AV_LOG_ERROR, "connect");
452                    return AVERROR(EIO);
453                }
454            }
455        }
456    }
457
458    return 0;
459}
460
461/**
462 * Return the local port used by the UDP connection
463 * @param h media file context
464 * @return the local port number
465 */
466int ff_udp_get_local_port(URLContext *h)
467{
468    UDPContext *s = h->priv_data;
469    return s->local_port;
470}
471
472/**
473 * Return the udp file handle for select() usage to wait for several RTP
474 * streams at the same time.
475 * @param h media file context
476 */
477static int udp_get_file_handle(URLContext *h)
478{
479    UDPContext *s = h->priv_data;
480    return s->udp_fd;
481}
482
483#if HAVE_PTHREAD_CANCEL
484static void *circular_buffer_task_rx( void *_URLContext)
485{
486    URLContext *h = _URLContext;
487    UDPContext *s = h->priv_data;
488    int old_cancelstate;
489
490    pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &old_cancelstate);
491    pthread_mutex_lock(&s->mutex);
492    if (ff_socket_nonblock(s->udp_fd, 0) < 0) {
493        av_log(h, AV_LOG_ERROR, "Failed to set blocking mode");
494        s->circular_buffer_error = AVERROR(EIO);
495        goto end;
496    }
497    while(1) {
498        int len;
499        struct sockaddr_storage addr;
500        socklen_t addr_len = sizeof(addr);
501
502        pthread_mutex_unlock(&s->mutex);
503        /* Blocking operations are always cancellation points;
504           see "General Information" / "Thread Cancelation Overview"
505           in Single Unix. */
506        pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &old_cancelstate);
507        len = recvfrom(s->udp_fd, s->tmp+4, sizeof(s->tmp)-4, 0, (struct sockaddr *)&addr, &addr_len);
508        pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &old_cancelstate);
509        pthread_mutex_lock(&s->mutex);
510        if (len < 0) {
511            if (ff_neterrno() != AVERROR(EAGAIN) && ff_neterrno() != AVERROR(EINTR)) {
512                s->circular_buffer_error = ff_neterrno();
513                goto end;
514            }
515            continue;
516        }
517        if (ff_ip_check_source_lists(&addr, &s->filters))
518            continue;
519        AV_WL32(s->tmp, len);
520
521        if (av_fifo_can_write(s->fifo) < len + 4) {
522            /* No Space left */
523            if (s->overrun_nonfatal) {
524                av_log(h, AV_LOG_WARNING, "Circular buffer overrun. "
525                        "Surviving due to overrun_nonfatal option\n");
526                continue;
527            } else {
528                av_log(h, AV_LOG_ERROR, "Circular buffer overrun. "
529                        "To avoid, increase fifo_size URL option. "
530                        "To survive in such case, use overrun_nonfatal option\n");
531                s->circular_buffer_error = AVERROR(EIO);
532                goto end;
533            }
534        }
535        av_fifo_write(s->fifo, s->tmp, len + 4);
536        pthread_cond_signal(&s->cond);
537    }
538
539end:
540    pthread_cond_signal(&s->cond);
541    pthread_mutex_unlock(&s->mutex);
542    return NULL;
543}
544
545static void *circular_buffer_task_tx( void *_URLContext)
546{
547    URLContext *h = _URLContext;
548    UDPContext *s = h->priv_data;
549    int64_t target_timestamp = av_gettime_relative();
550    int64_t start_timestamp = av_gettime_relative();
551    int64_t sent_bits = 0;
552    int64_t burst_interval = s->bitrate ? (s->burst_bits * 1000000 / s->bitrate) : 0;
553    int64_t max_delay = s->bitrate ?  ((int64_t)h->max_packet_size * 8 * 1000000 / s->bitrate + 1) : 0;
554
555    pthread_mutex_lock(&s->mutex);
556
557    if (ff_socket_nonblock(s->udp_fd, 0) < 0) {
558        av_log(h, AV_LOG_ERROR, "Failed to set blocking mode");
559        s->circular_buffer_error = AVERROR(EIO);
560        goto end;
561    }
562
563    for(;;) {
564        int len;
565        const uint8_t *p;
566        uint8_t tmp[4];
567        int64_t timestamp;
568
569        len = av_fifo_can_read(s->fifo);
570
571        while (len<4) {
572            if (s->close_req)
573                goto end;
574            pthread_cond_wait(&s->cond, &s->mutex);
575            len = av_fifo_can_read(s->fifo);
576        }
577
578        av_fifo_read(s->fifo, tmp, 4);
579        len = AV_RL32(tmp);
580
581        av_assert0(len >= 0);
582        av_assert0(len <= sizeof(s->tmp));
583
584        av_fifo_read(s->fifo, s->tmp, len);
585
586        pthread_mutex_unlock(&s->mutex);
587
588        if (s->bitrate) {
589            timestamp = av_gettime_relative();
590            if (timestamp < target_timestamp) {
591                int64_t delay = target_timestamp - timestamp;
592                if (delay > max_delay) {
593                    delay = max_delay;
594                    start_timestamp = timestamp + delay;
595                    sent_bits = 0;
596                }
597                av_usleep(delay);
598            } else {
599                if (timestamp - burst_interval > target_timestamp) {
600                    start_timestamp = timestamp - burst_interval;
601                    sent_bits = 0;
602                }
603            }
604            sent_bits += len * 8;
605            target_timestamp = start_timestamp + sent_bits * 1000000 / s->bitrate;
606        }
607
608        p = s->tmp;
609        while (len) {
610            int ret;
611            av_assert0(len > 0);
612            if (!s->is_connected) {
613                ret = sendto (s->udp_fd, p, len, 0,
614                            (struct sockaddr *) &s->dest_addr,
615                            s->dest_addr_len);
616            } else
617                ret = send(s->udp_fd, p, len, 0);
618            if (ret >= 0) {
619                len -= ret;
620                p   += ret;
621            } else {
622                ret = ff_neterrno();
623                if (ret != AVERROR(EAGAIN) && ret != AVERROR(EINTR)) {
624                    pthread_mutex_lock(&s->mutex);
625                    s->circular_buffer_error = ret;
626                    pthread_mutex_unlock(&s->mutex);
627                    return NULL;
628                }
629            }
630        }
631
632        pthread_mutex_lock(&s->mutex);
633    }
634
635end:
636    pthread_mutex_unlock(&s->mutex);
637    return NULL;
638}
639
640
641#endif
642
643/* put it in UDP context */
644/* return non zero if error */
645static int udp_open(URLContext *h, const char *uri, int flags)
646{
647    char hostname[1024];
648    int port, udp_fd = -1, tmp, bind_ret = -1, dscp = -1;
649    UDPContext *s = h->priv_data;
650    int is_output;
651    const char *p;
652    char buf[256];
653    struct sockaddr_storage my_addr;
654    socklen_t len;
655    int ret;
656
657    h->is_streamed = 1;
658
659    is_output = !(flags & AVIO_FLAG_READ);
660    if (s->buffer_size < 0)
661        s->buffer_size = is_output ? UDP_TX_BUF_SIZE : UDP_RX_BUF_SIZE;
662
663    if (s->sources) {
664        if ((ret = ff_ip_parse_sources(h, s->sources, &s->filters)) < 0)
665            goto fail;
666    }
667
668    if (s->block) {
669        if ((ret = ff_ip_parse_blocks(h, s->block, &s->filters)) < 0)
670            goto fail;
671    }
672
673    p = strchr(uri, '?');
674    if (p) {
675        if (av_find_info_tag(buf, sizeof(buf), "reuse", p)) {
676            char *endptr = NULL;
677            s->reuse_socket = strtol(buf, &endptr, 10);
678            /* assume if no digits were found it is a request to enable it */
679            if (buf == endptr)
680                s->reuse_socket = 1;
681        }
682        if (av_find_info_tag(buf, sizeof(buf), "overrun_nonfatal", p)) {
683            char *endptr = NULL;
684            s->overrun_nonfatal = strtol(buf, &endptr, 10);
685            /* assume if no digits were found it is a request to enable it */
686            if (buf == endptr)
687                s->overrun_nonfatal = 1;
688            if (!HAVE_PTHREAD_CANCEL)
689                av_log(h, AV_LOG_WARNING,
690                       "'overrun_nonfatal' option was set but it is not supported "
691                       "on this build (pthread support is required)\n");
692        }
693        if (av_find_info_tag(buf, sizeof(buf), "ttl", p)) {
694            s->ttl = strtol(buf, NULL, 10);
695            if (s->ttl < 0 || s->ttl > 255) {
696                av_log(h, AV_LOG_ERROR, "ttl(%d) should be in range [0,255]\n", s->ttl);
697                ret = AVERROR(EINVAL);
698                goto fail;
699            }
700        }
701        if (av_find_info_tag(buf, sizeof(buf), "udplite_coverage", p)) {
702            s->udplite_coverage = strtol(buf, NULL, 10);
703        }
704        if (av_find_info_tag(buf, sizeof(buf), "localport", p)) {
705            s->local_port = strtol(buf, NULL, 10);
706        }
707        if (av_find_info_tag(buf, sizeof(buf), "pkt_size", p)) {
708            s->pkt_size = strtol(buf, NULL, 10);
709        }
710        if (av_find_info_tag(buf, sizeof(buf), "buffer_size", p)) {
711            s->buffer_size = strtol(buf, NULL, 10);
712        }
713        if (av_find_info_tag(buf, sizeof(buf), "connect", p)) {
714            s->is_connected = strtol(buf, NULL, 10);
715        }
716        if (av_find_info_tag(buf, sizeof(buf), "dscp", p)) {
717            dscp = strtol(buf, NULL, 10);
718        }
719        if (av_find_info_tag(buf, sizeof(buf), "fifo_size", p)) {
720            s->circular_buffer_size = strtol(buf, NULL, 10);
721            if (!HAVE_PTHREAD_CANCEL)
722                av_log(h, AV_LOG_WARNING,
723                       "'circular_buffer_size' option was set but it is not supported "
724                       "on this build (pthread support is required)\n");
725        }
726        if (av_find_info_tag(buf, sizeof(buf), "bitrate", p)) {
727            s->bitrate = strtoll(buf, NULL, 10);
728            if (!HAVE_PTHREAD_CANCEL)
729                av_log(h, AV_LOG_WARNING,
730                       "'bitrate' option was set but it is not supported "
731                       "on this build (pthread support is required)\n");
732        }
733        if (av_find_info_tag(buf, sizeof(buf), "burst_bits", p)) {
734            s->burst_bits = strtoll(buf, NULL, 10);
735        }
736        if (av_find_info_tag(buf, sizeof(buf), "localaddr", p)) {
737            av_freep(&s->localaddr);
738            s->localaddr = av_strdup(buf);
739        }
740        if (av_find_info_tag(buf, sizeof(buf), "sources", p)) {
741            if ((ret = ff_ip_parse_sources(h, buf, &s->filters)) < 0)
742                goto fail;
743        }
744        if (av_find_info_tag(buf, sizeof(buf), "block", p)) {
745            if ((ret = ff_ip_parse_blocks(h, buf, &s->filters)) < 0)
746                goto fail;
747        }
748        if (!is_output && av_find_info_tag(buf, sizeof(buf), "timeout", p))
749            s->timeout = strtol(buf, NULL, 10);
750        if (is_output && av_find_info_tag(buf, sizeof(buf), "broadcast", p))
751            s->is_broadcast = strtol(buf, NULL, 10);
752    }
753    /* handling needed to support options picking from both AVOption and URL */
754    s->circular_buffer_size *= 188;
755    if (flags & AVIO_FLAG_WRITE) {
756        h->max_packet_size = s->pkt_size;
757    } else {
758        h->max_packet_size = UDP_MAX_PKT_SIZE;
759    }
760    h->rw_timeout = s->timeout;
761
762    /* fill the dest addr */
763    av_url_split(NULL, 0, NULL, 0, hostname, sizeof(hostname), &port, NULL, 0, uri);
764
765    /* XXX: fix av_url_split */
766    if (hostname[0] == '\0' || hostname[0] == '?') {
767        /* only accepts null hostname if input */
768        if (!(flags & AVIO_FLAG_READ)) {
769            ret = AVERROR(EINVAL);
770            goto fail;
771        }
772    } else {
773        if ((ret = ff_udp_set_remote_url(h, uri)) < 0)
774            goto fail;
775    }
776
777    if ((s->is_multicast || s->local_port <= 0) && (h->flags & AVIO_FLAG_READ))
778        s->local_port = port;
779
780    udp_fd = udp_socket_create(h, &my_addr, &len, s->localaddr);
781    if (udp_fd < 0) {
782        ret = AVERROR(EIO);
783        goto fail;
784    }
785
786    s->local_addr_storage=my_addr; //store for future multicast join
787
788    /* Follow the requested reuse option, unless it's multicast in which
789     * case enable reuse unless explicitly disabled.
790     */
791    if (s->reuse_socket > 0 || (s->is_multicast && s->reuse_socket < 0)) {
792        s->reuse_socket = 1;
793        if (setsockopt (udp_fd, SOL_SOCKET, SO_REUSEADDR, &(s->reuse_socket), sizeof(s->reuse_socket)) != 0) {
794            ret = ff_neterrno();
795            goto fail;
796        }
797    }
798
799    if (s->is_broadcast) {
800#ifdef SO_BROADCAST
801        if (setsockopt (udp_fd, SOL_SOCKET, SO_BROADCAST, &(s->is_broadcast), sizeof(s->is_broadcast)) != 0) {
802            ret = ff_neterrno();
803            goto fail;
804        }
805#else
806        ret = AVERROR(ENOSYS);
807        goto fail;
808#endif
809    }
810
811    /* Set the checksum coverage for UDP-Lite (RFC 3828) for sending and receiving.
812     * The receiver coverage has to be less than or equal to the sender coverage.
813     * Otherwise, the receiver will drop all packets.
814     */
815    if (s->udplite_coverage) {
816        if (setsockopt (udp_fd, IPPROTO_UDPLITE, UDPLITE_SEND_CSCOV, &(s->udplite_coverage), sizeof(s->udplite_coverage)) != 0)
817            av_log(h, AV_LOG_WARNING, "socket option UDPLITE_SEND_CSCOV not available");
818
819        if (setsockopt (udp_fd, IPPROTO_UDPLITE, UDPLITE_RECV_CSCOV, &(s->udplite_coverage), sizeof(s->udplite_coverage)) != 0)
820            av_log(h, AV_LOG_WARNING, "socket option UDPLITE_RECV_CSCOV not available");
821    }
822
823    if (dscp >= 0) {
824        dscp <<= 2;
825        if (setsockopt (udp_fd, IPPROTO_IP, IP_TOS, &dscp, sizeof(dscp)) != 0) {
826            ret = ff_neterrno();
827            goto fail;
828        }
829    }
830
831    /* If multicast, try binding the multicast address first, to avoid
832     * receiving UDP packets from other sources aimed at the same UDP
833     * port. This fails on windows. This makes sending to the same address
834     * using sendto() fail, so only do it if we're opened in read-only mode. */
835    if (s->is_multicast && (h->flags & AVIO_FLAG_READ)) {
836        bind_ret = bind(udp_fd,(struct sockaddr *)&s->dest_addr, len);
837    }
838    /* bind to the local address if not multicast or if the multicast
839     * bind failed */
840    /* the bind is needed to give a port to the socket now */
841    if (bind_ret < 0 && bind(udp_fd,(struct sockaddr *)&my_addr, len) < 0) {
842        ff_log_net_error(h, AV_LOG_ERROR, "bind failed");
843        ret = ff_neterrno();
844        goto fail;
845    }
846
847    len = sizeof(my_addr);
848    getsockname(udp_fd, (struct sockaddr *)&my_addr, &len);
849    s->local_port = udp_port(&my_addr, len);
850
851    if (s->is_multicast) {
852        if (h->flags & AVIO_FLAG_WRITE) {
853            /* output */
854            if ((ret = udp_set_multicast_ttl(udp_fd, s->ttl, (struct sockaddr *)&s->dest_addr, h)) < 0)
855                goto fail;
856        }
857        if (h->flags & AVIO_FLAG_READ) {
858            /* input */
859            if (s->filters.nb_include_addrs) {
860                if ((ret = udp_set_multicast_sources(h, udp_fd,
861                                              (struct sockaddr *)&s->dest_addr,
862                                              s->dest_addr_len, &s->local_addr_storage,
863                                              s->filters.include_addrs,
864                                              s->filters.nb_include_addrs, 1)) < 0)
865                    goto fail;
866            } else {
867                if ((ret = udp_join_multicast_group(udp_fd, (struct sockaddr *)&s->dest_addr,
868                                                    (struct sockaddr *)&s->local_addr_storage, h)) < 0)
869                    goto fail;
870            }
871            if (s->filters.nb_exclude_addrs) {
872                if ((ret = udp_set_multicast_sources(h, udp_fd,
873                                              (struct sockaddr *)&s->dest_addr,
874                                              s->dest_addr_len, &s->local_addr_storage,
875                                              s->filters.exclude_addrs,
876                                              s->filters.nb_exclude_addrs, 0)) < 0)
877                    goto fail;
878            }
879        }
880    }
881
882    if (is_output) {
883        /* limit the tx buf size to limit latency */
884        tmp = s->buffer_size;
885        if (setsockopt(udp_fd, SOL_SOCKET, SO_SNDBUF, &tmp, sizeof(tmp)) < 0) {
886            ff_log_net_error(h, AV_LOG_ERROR, "setsockopt(SO_SNDBUF)");
887            ret = ff_neterrno();
888            goto fail;
889        }
890    } else {
891        /* set udp recv buffer size to the requested value (default UDP_RX_BUF_SIZE) */
892        tmp = s->buffer_size;
893        if (setsockopt(udp_fd, SOL_SOCKET, SO_RCVBUF, &tmp, sizeof(tmp)) < 0) {
894            ff_log_net_error(h, AV_LOG_WARNING, "setsockopt(SO_RECVBUF)");
895        }
896        len = sizeof(tmp);
897        if (getsockopt(udp_fd, SOL_SOCKET, SO_RCVBUF, &tmp, &len) < 0) {
898            ff_log_net_error(h, AV_LOG_WARNING, "getsockopt(SO_RCVBUF)");
899        } else {
900            av_log(h, AV_LOG_DEBUG, "end receive buffer size reported is %d\n", tmp);
901            if(tmp < s->buffer_size)
902                av_log(h, AV_LOG_WARNING, "attempted to set receive buffer to size %d but it only ended up set as %d\n", s->buffer_size, tmp);
903        }
904
905        /* make the socket non-blocking */
906        ff_socket_nonblock(udp_fd, 1);
907    }
908    if (s->is_connected) {
909        if (connect(udp_fd, (struct sockaddr *) &s->dest_addr, s->dest_addr_len)) {
910            ff_log_net_error(h, AV_LOG_ERROR, "connect");
911            ret = ff_neterrno();
912            goto fail;
913        }
914    }
915
916    s->udp_fd = udp_fd;
917
918#if HAVE_PTHREAD_CANCEL
919    /*
920      Create thread in case of:
921      1. Input and circular_buffer_size is set
922      2. Output and bitrate and circular_buffer_size is set
923    */
924
925    if (is_output && s->bitrate && !s->circular_buffer_size) {
926        /* Warn user in case of 'circular_buffer_size' is not set */
927        av_log(h, AV_LOG_WARNING,"'bitrate' option was set but 'circular_buffer_size' is not, but required\n");
928    }
929
930    if ((!is_output && s->circular_buffer_size) || (is_output && s->bitrate && s->circular_buffer_size)) {
931        /* start the task going */
932        s->fifo = av_fifo_alloc2(s->circular_buffer_size, 1, 0);
933        if (!s->fifo) {
934            ret = AVERROR(ENOMEM);
935            goto fail;
936        }
937        ret = pthread_mutex_init(&s->mutex, NULL);
938        if (ret != 0) {
939            av_log(h, AV_LOG_ERROR, "pthread_mutex_init failed : %s\n", strerror(ret));
940            ret = AVERROR(ret);
941            goto fail;
942        }
943        ret = pthread_cond_init(&s->cond, NULL);
944        if (ret != 0) {
945            av_log(h, AV_LOG_ERROR, "pthread_cond_init failed : %s\n", strerror(ret));
946            ret = AVERROR(ret);
947            goto cond_fail;
948        }
949        ret = pthread_create(&s->circular_buffer_thread, NULL, is_output?circular_buffer_task_tx:circular_buffer_task_rx, h);
950        if (ret != 0) {
951            av_log(h, AV_LOG_ERROR, "pthread_create failed : %s\n", strerror(ret));
952            ret = AVERROR(ret);
953            goto thread_fail;
954        }
955        s->thread_started = 1;
956    }
957#endif
958
959    return 0;
960#if HAVE_PTHREAD_CANCEL
961 thread_fail:
962    pthread_cond_destroy(&s->cond);
963 cond_fail:
964    pthread_mutex_destroy(&s->mutex);
965#endif
966 fail:
967    if (udp_fd >= 0)
968        closesocket(udp_fd);
969    av_fifo_freep2(&s->fifo);
970    ff_ip_reset_filters(&s->filters);
971    return ret;
972}
973
974static int udplite_open(URLContext *h, const char *uri, int flags)
975{
976    UDPContext *s = h->priv_data;
977
978    // set default checksum coverage
979    s->udplite_coverage = UDP_HEADER_SIZE;
980
981    return udp_open(h, uri, flags);
982}
983
984static int udp_read(URLContext *h, uint8_t *buf, int size)
985{
986    UDPContext *s = h->priv_data;
987    int ret;
988    struct sockaddr_storage addr;
989    socklen_t addr_len = sizeof(addr);
990#if HAVE_PTHREAD_CANCEL
991    int avail, nonblock = h->flags & AVIO_FLAG_NONBLOCK;
992
993    if (s->fifo) {
994        pthread_mutex_lock(&s->mutex);
995        do {
996            avail = av_fifo_can_read(s->fifo);
997            if (avail) { // >=size) {
998                uint8_t tmp[4];
999
1000                av_fifo_read(s->fifo, tmp, 4);
1001                avail = AV_RL32(tmp);
1002                if(avail > size){
1003                    av_log(h, AV_LOG_WARNING, "Part of datagram lost due to insufficient buffer size\n");
1004                    avail = size;
1005                }
1006
1007                av_fifo_read(s->fifo, buf, avail);
1008                av_fifo_drain2(s->fifo, AV_RL32(tmp) - avail);
1009                pthread_mutex_unlock(&s->mutex);
1010                return avail;
1011            } else if(s->circular_buffer_error){
1012                int err = s->circular_buffer_error;
1013                pthread_mutex_unlock(&s->mutex);
1014                return err;
1015            } else if(nonblock) {
1016                pthread_mutex_unlock(&s->mutex);
1017                return AVERROR(EAGAIN);
1018            } else {
1019                /* FIXME: using the monotonic clock would be better,
1020                   but it does not exist on all supported platforms. */
1021                int64_t t = av_gettime() + 100000;
1022                struct timespec tv = { .tv_sec  =  t / 1000000,
1023                                       .tv_nsec = (t % 1000000) * 1000 };
1024                int err = pthread_cond_timedwait(&s->cond, &s->mutex, &tv);
1025                if (err) {
1026                    pthread_mutex_unlock(&s->mutex);
1027                    return AVERROR(err == ETIMEDOUT ? EAGAIN : err);
1028                }
1029                nonblock = 1;
1030            }
1031        } while(1);
1032    }
1033#endif
1034
1035    if (!(h->flags & AVIO_FLAG_NONBLOCK)) {
1036        ret = ff_network_wait_fd(s->udp_fd, 0);
1037        if (ret < 0)
1038            return ret;
1039    }
1040    ret = recvfrom(s->udp_fd, buf, size, 0, (struct sockaddr *)&addr, &addr_len);
1041    if (ret < 0)
1042        return ff_neterrno();
1043    if (ff_ip_check_source_lists(&addr, &s->filters))
1044        return AVERROR(EINTR);
1045    return ret;
1046}
1047
1048static int udp_write(URLContext *h, const uint8_t *buf, int size)
1049{
1050    UDPContext *s = h->priv_data;
1051    int ret;
1052
1053#if HAVE_PTHREAD_CANCEL
1054    if (s->fifo) {
1055        uint8_t tmp[4];
1056
1057        pthread_mutex_lock(&s->mutex);
1058
1059        /*
1060          Return error if last tx failed.
1061          Here we can't know on which packet error was, but it needs to know that error exists.
1062        */
1063        if (s->circular_buffer_error<0) {
1064            int err = s->circular_buffer_error;
1065            pthread_mutex_unlock(&s->mutex);
1066            return err;
1067        }
1068
1069        if (av_fifo_can_write(s->fifo) < size + 4) {
1070            /* What about a partial packet tx ? */
1071            pthread_mutex_unlock(&s->mutex);
1072            return AVERROR(ENOMEM);
1073        }
1074        AV_WL32(tmp, size);
1075        av_fifo_write(s->fifo, tmp, 4); /* size of packet */
1076        av_fifo_write(s->fifo, buf, size); /* the data */
1077        pthread_cond_signal(&s->cond);
1078        pthread_mutex_unlock(&s->mutex);
1079        return size;
1080    }
1081#endif
1082    if (!(h->flags & AVIO_FLAG_NONBLOCK)) {
1083        ret = ff_network_wait_fd(s->udp_fd, 1);
1084        if (ret < 0)
1085            return ret;
1086    }
1087
1088    if (!s->is_connected) {
1089        ret = sendto (s->udp_fd, buf, size, 0,
1090                      (struct sockaddr *) &s->dest_addr,
1091                      s->dest_addr_len);
1092    } else
1093        ret = send(s->udp_fd, buf, size, 0);
1094
1095    return ret < 0 ? ff_neterrno() : ret;
1096}
1097
1098static int udp_close(URLContext *h)
1099{
1100    UDPContext *s = h->priv_data;
1101
1102#if HAVE_PTHREAD_CANCEL
1103    // Request close once writing is finished
1104    if (s->thread_started && !(h->flags & AVIO_FLAG_READ)) {
1105        pthread_mutex_lock(&s->mutex);
1106        s->close_req = 1;
1107        pthread_cond_signal(&s->cond);
1108        pthread_mutex_unlock(&s->mutex);
1109    }
1110#endif
1111
1112    if (s->is_multicast && (h->flags & AVIO_FLAG_READ))
1113        udp_leave_multicast_group(s->udp_fd, (struct sockaddr *)&s->dest_addr,
1114                                  (struct sockaddr *)&s->local_addr_storage, h);
1115#if HAVE_PTHREAD_CANCEL
1116    if (s->thread_started) {
1117        int ret;
1118        // Cancel only read, as write has been signaled as success to the user
1119        if (h->flags & AVIO_FLAG_READ) {
1120#ifdef _WIN32
1121            /* recvfrom() is not a cancellation point for win32, so we shutdown
1122             * the socket and abort pending IO, subsequent recvfrom() calls
1123             * will fail with WSAESHUTDOWN causing the thread to exit. */
1124            shutdown(s->udp_fd, SD_RECEIVE);
1125            CancelIoEx((HANDLE)(SOCKET)s->udp_fd, NULL);
1126#else
1127            pthread_cancel(s->circular_buffer_thread);
1128#endif
1129        }
1130        ret = pthread_join(s->circular_buffer_thread, NULL);
1131        if (ret != 0)
1132            av_log(h, AV_LOG_ERROR, "pthread_join(): %s\n", strerror(ret));
1133        pthread_mutex_destroy(&s->mutex);
1134        pthread_cond_destroy(&s->cond);
1135    }
1136#endif
1137    closesocket(s->udp_fd);
1138    av_fifo_freep2(&s->fifo);
1139    ff_ip_reset_filters(&s->filters);
1140    return 0;
1141}
1142
1143const URLProtocol ff_udp_protocol = {
1144    .name                = "udp",
1145    .url_open            = udp_open,
1146    .url_read            = udp_read,
1147    .url_write           = udp_write,
1148    .url_close           = udp_close,
1149    .url_get_file_handle = udp_get_file_handle,
1150    .priv_data_size      = sizeof(UDPContext),
1151    .priv_data_class     = &udp_class,
1152    .flags               = URL_PROTOCOL_FLAG_NETWORK,
1153};
1154
1155const URLProtocol ff_udplite_protocol = {
1156    .name                = "udplite",
1157    .url_open            = udplite_open,
1158    .url_read            = udp_read,
1159    .url_write           = udp_write,
1160    .url_close           = udp_close,
1161    .url_get_file_handle = udp_get_file_handle,
1162    .priv_data_size      = sizeof(UDPContext),
1163    .priv_data_class     = &udplite_context_class,
1164    .flags               = URL_PROTOCOL_FLAG_NETWORK,
1165};
1166