text: /*
   * 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
   */
  
  /**
   * @file
   * Haivision Open SRT (Secure Reliable Transport) protocol
   */
  
  #include <srt/srt.h>
  
  #include "libavutil/opt.h"
  #include "libavutil/parseutils.h"
  #include "libavutil/time.h"
  
  #include "avformat.h"
  #include "internal.h"
  #include "network.h"
  #include "os_support.h"
  #include "url.h"
  
  /* This is for MPEG-TS and it's a default SRTO_PAYLOADSIZE for SRTT_LIVE (8 TS packets) */
  #ifndef SRT_LIVE_DEFAULT_PAYLOAD_SIZE
  #define SRT_LIVE_DEFAULT_PAYLOAD_SIZE 1316
  #endif
  
  /* This is the maximum payload size for Live mode, should you have a different payload type than MPEG-TS */
  #ifndef SRT_LIVE_MAX_PAYLOAD_SIZE
  #define SRT_LIVE_MAX_PAYLOAD_SIZE 1456
  #endif
  
  enum SRTMode {
      SRT_MODE_CALLER = 0,
      SRT_MODE_LISTENER = 1,
      SRT_MODE_RENDEZVOUS = 2
  };
  
  typedef struct SRTContext {
      const AVClass *class;
      int fd;
      int eid;
      int64_t rw_timeout;
      int64_t listen_timeout;
      int recv_buffer_size;
      int send_buffer_size;
  
      int64_t maxbw;
      int pbkeylen;
      char *passphrase;
  #if SRT_VERSION_VALUE >= 0x010302
      int enforced_encryption;
      int kmrefreshrate;
      int kmpreannounce;
  #endif
      int mss;
      int ffs;
      int ipttl;
      int iptos;
      int64_t inputbw;
      int oheadbw;
      int64_t latency;
      int tlpktdrop;
      int nakreport;
      int64_t connect_timeout;
      int payload_size;
      int64_t rcvlatency;
      int64_t peerlatency;
      enum SRTMode mode;
      int sndbuf;
      int rcvbuf;
      int lossmaxttl;
      int minversion;
      char *streamid;
      char *smoother;
      int messageapi;
      SRT_TRANSTYPE transtype;
      int linger;
      int tsbpd;
  } SRTContext;
  
  #define D AV_OPT_FLAG_DECODING_PARAM
  #define E AV_OPT_FLAG_ENCODING_PARAM
  #define OFFSET(x) offsetof(SRTContext, x)
  static const AVOption libsrt_options[] = {
      { "timeout",        "Timeout of socket I/O operations (in microseconds)",                   OFFSET(rw_timeout),       AV_OPT_TYPE_INT64, { .i64 = -1 }, -1, INT64_MAX, .flags = D|E },
      { "listen_timeout", "Connection awaiting timeout (in microseconds)" ,                       OFFSET(listen_timeout),   AV_OPT_TYPE_INT64, { .i64 = -1 }, -1, INT64_MAX, .flags = D|E },
      { "send_buffer_size", "Socket send buffer size (in bytes)",                                 OFFSET(send_buffer_size), AV_OPT_TYPE_INT,      { .i64 = -1 }, -1, INT_MAX,   .flags = D|E },
      { "recv_buffer_size", "Socket receive buffer size (in bytes)",                              OFFSET(recv_buffer_size), AV_OPT_TYPE_INT,      { .i64 = -1 }, -1, INT_MAX,   .flags = D|E },
      { "pkt_size",       "Maximum SRT packet size",                                              OFFSET(payload_size),     AV_OPT_TYPE_INT,      { .i64 = -1 }, -1, SRT_LIVE_MAX_PAYLOAD_SIZE, .flags = D|E, "payload_size" },
      { "payload_size",   "Maximum SRT packet size",                                              OFFSET(payload_size),     AV_OPT_TYPE_INT,      { .i64 = -1 }, -1, SRT_LIVE_MAX_PAYLOAD_SIZE, .flags = D|E, "payload_size" },
      { "ts_size",        NULL, 0, AV_OPT_TYPE_CONST,  { .i64 = SRT_LIVE_DEFAULT_PAYLOAD_SIZE }, INT_MIN, INT_MAX, .flags = D|E, "payload_size" },
      { "max_size",       NULL, 0, AV_OPT_TYPE_CONST,  { .i64 = SRT_LIVE_MAX_PAYLOAD_SIZE },     INT_MIN, INT_MAX, .flags = D|E, "payload_size" },
      { "maxbw",          "Maximum bandwidth (bytes per second) that the connection can use",     OFFSET(maxbw),            AV_OPT_TYPE_INT64,    { .i64 = -1 }, -1, INT64_MAX, .flags = D|E },
      { "pbkeylen",       "Crypto key len in bytes {16,24,32} Default: 16 (128-bit)",             OFFSET(pbkeylen),         AV_OPT_TYPE_INT,      { .i64 = -1 }, -1, 32,        .flags = D|E },
      { "passphrase",     "Crypto PBKDF2 Passphrase size[0,10..64] 0:disable crypto",             OFFSET(passphrase),       AV_OPT_TYPE_STRING,   { .str = NULL },              .flags = D|E },
  #if SRT_VERSION_VALUE >= 0x010302
      { "enforced_encryption", "Enforces that both connection parties have the same passphrase set",                              OFFSET(enforced_encryption), AV_OPT_TYPE_BOOL,  { .i64 = -1 }, -1, 1,         .flags = D|E },
      { "kmrefreshrate",       "The number of packets to be transmitted after which the encryption key is switched to a new key", OFFSET(kmrefreshrate),       AV_OPT_TYPE_INT,   { .i64 = -1 }, -1, INT_MAX,   .flags = D|E },
      { "kmpreannounce",       "The interval between when a new encryption key is sent and when switchover occurs",               OFFSET(kmpreannounce),       AV_OPT_TYPE_INT,   { .i64 = -1 }, -1, INT_MAX,   .flags = D|E },
  #endif
      { "mss",            "The Maximum Segment Size",                                             OFFSET(mss),              AV_OPT_TYPE_INT,      { .i64 = -1 }, -1, 1500,      .flags = D|E },
      { "ffs",            "Flight flag size (window size) (in bytes)",                            OFFSET(ffs),              AV_OPT_TYPE_INT,      { .i64 = -1 }, -1, INT_MAX,   .flags = D|E },
      { "ipttl",          "IP Time To Live",                                                      OFFSET(ipttl),            AV_OPT_TYPE_INT,      { .i64 = -1 }, -1, 255,       .flags = D|E },
      { "iptos",          "IP Type of Service",                                                   OFFSET(iptos),            AV_OPT_TYPE_INT,      { .i64 = -1 }, -1, 255,       .flags = D|E },
      { "inputbw",        "Estimated input stream rate",                                          OFFSET(inputbw),          AV_OPT_TYPE_INT64,    { .i64 = -1 }, -1, INT64_MAX, .flags = D|E },
      { "oheadbw",        "MaxBW ceiling based on % over input stream rate",                      OFFSET(oheadbw),          AV_OPT_TYPE_INT,      { .i64 = -1 }, -1, 100,       .flags = D|E },
      { "latency",        "receiver delay (in microseconds) to absorb bursts of missed packet retransmissions",                     OFFSET(latency),          AV_OPT_TYPE_INT64, { .i64 = -1 }, -1, INT64_MAX, .flags = D|E },
      { "tsbpddelay",     "deprecated, same effect as latency option",                            OFFSET(latency),          AV_OPT_TYPE_INT64, { .i64 = -1 }, -1, INT64_MAX, .flags = D|E },
      { "rcvlatency",     "receive latency (in microseconds)",                                    OFFSET(rcvlatency),       AV_OPT_TYPE_INT64, { .i64 = -1 }, -1, INT64_MAX, .flags = D|E },
      { "peerlatency",    "peer latency (in microseconds)",                                       OFFSET(peerlatency),      AV_OPT_TYPE_INT64, { .i64 = -1 }, -1, INT64_MAX, .flags = D|E },
      { "tlpktdrop",      "Enable too-late pkt drop",                                             OFFSET(tlpktdrop),        AV_OPT_TYPE_BOOL,     { .i64 = -1 }, -1, 1,         .flags = D|E },
      { "nakreport",      "Enable receiver to send periodic NAK reports",                         OFFSET(nakreport),        AV_OPT_TYPE_BOOL,     { .i64 = -1 }, -1, 1,         .flags = D|E },
      { "connect_timeout", "Connect timeout(in milliseconds). Caller default: 3000, rendezvous (x 10)",                            OFFSET(connect_timeout),  AV_OPT_TYPE_INT64, { .i64 = -1 }, -1, INT64_MAX, .flags = D|E },
      { "mode",           "Connection mode (caller, listener, rendezvous)",                       OFFSET(mode),             AV_OPT_TYPE_INT,      { .i64 = SRT_MODE_CALLER }, SRT_MODE_CALLER, SRT_MODE_RENDEZVOUS, .flags = D|E, "mode" },
      { "caller",         NULL, 0, AV_OPT_TYPE_CONST,  { .i64 = SRT_MODE_CALLER },     INT_MIN, INT_MAX, .flags = D|E, "mode" },
      { "listener",       NULL, 0, AV_OPT_TYPE_CONST,  { .i64 = SRT_MODE_LISTENER },   INT_MIN, INT_MAX, .flags = D|E, "mode" },
      { "rendezvous",     NULL, 0, AV_OPT_TYPE_CONST,  { .i64 = SRT_MODE_RENDEZVOUS }, INT_MIN, INT_MAX, .flags = D|E, "mode" },
      { "sndbuf",         "Send buffer size (in bytes)",                                          OFFSET(sndbuf),           AV_OPT_TYPE_INT,      { .i64 = -1 }, -1, INT_MAX,   .flags = D|E },
      { "rcvbuf",         "Receive buffer size (in bytes)",                                       OFFSET(rcvbuf),           AV_OPT_TYPE_INT,      { .i64 = -1 }, -1, INT_MAX,   .flags = D|E },
      { "lossmaxttl",     "Maximum possible packet reorder tolerance",                            OFFSET(lossmaxttl),       AV_OPT_TYPE_INT,      { .i64 = -1 }, -1, INT_MAX,   .flags = D|E },
      { "minversion",     "The minimum SRT version that is required from the peer",               OFFSET(minversion),       AV_OPT_TYPE_INT,      { .i64 = -1 }, -1, INT_MAX,   .flags = D|E },
      { "streamid",       "A string of up to 512 characters that an Initiator can pass to a Responder",  OFFSET(streamid),  AV_OPT_TYPE_STRING,   { .str = NULL },              .flags = D|E },
      { "srt_streamid",   "A string of up to 512 characters that an Initiator can pass to a Responder",  OFFSET(streamid),  AV_OPT_TYPE_STRING,   { .str = NULL },              .flags = D|E },
      { "smoother",       "The type of Smoother used for the transmission for that socket",       OFFSET(smoother),         AV_OPT_TYPE_STRING,   { .str = NULL },              .flags = D|E },
      { "messageapi",     "Enable message API",                                                   OFFSET(messageapi),       AV_OPT_TYPE_BOOL,     { .i64 = -1 }, -1, 1,         .flags = D|E },
      { "transtype",      "The transmission type for the socket",                                 OFFSET(transtype),        AV_OPT_TYPE_INT,      { .i64 = SRTT_INVALID }, SRTT_LIVE, SRTT_INVALID, .flags = D|E, "transtype" },
      { "live",           NULL, 0, AV_OPT_TYPE_CONST,  { .i64 = SRTT_LIVE }, INT_MIN, INT_MAX, .flags = D|E, "transtype" },
      { "file",           NULL, 0, AV_OPT_TYPE_CONST,  { .i64 = SRTT_FILE }, INT_MIN, INT_MAX, .flags = D|E, "transtype" },
      { "linger",         "Number of seconds that the socket waits for unsent data when closing", OFFSET(linger),           AV_OPT_TYPE_INT,      { .i64 = -1 }, -1, INT_MAX,   .flags = D|E },
      { "tsbpd",          "Timestamp-based packet delivery",                                      OFFSET(tsbpd),            AV_OPT_TYPE_BOOL,     { .i64 = -1 }, -1, 1,         .flags = D|E },
      { NULL }
  };
  
  static int libsrt_neterrno(URLContext *h)
  {
      int os_errno;
      int err = srt_getlasterror(&os_errno);
      if (err == SRT_EASYNCRCV || err == SRT_EASYNCSND)
          return AVERROR(EAGAIN);
      av_log(h, AV_LOG_ERROR, "%s\n", srt_getlasterror_str());
      return os_errno ? AVERROR(os_errno) : AVERROR_UNKNOWN;
  }
  
  static int libsrt_getsockopt(URLContext *h, int fd, SRT_SOCKOPT optname, const char * optnamestr, void * optval, int * optlen)
  {
      if (srt_getsockopt(fd, 0, optname, optval, optlen) < 0) {
          av_log(h, AV_LOG_ERROR, "failed to get option %s on socket: %s\n", optnamestr, srt_getlasterror_str());
          return AVERROR(EIO);
      }
      return 0;
  }
  
  static int libsrt_socket_nonblock(int socket, int enable)
  {
      int ret, blocking = enable ? 0 : 1;
      /* Setting SRTO_{SND,RCV}SYN options to 1 enable blocking mode, setting them to 0 enable non-blocking mode. */
      ret = srt_setsockopt(socket, 0, SRTO_SNDSYN, &blocking, sizeof(blocking));
      if (ret < 0)
          return ret;
      return srt_setsockopt(socket, 0, SRTO_RCVSYN, &blocking, sizeof(blocking));
  }
  
  static int libsrt_epoll_create(URLContext *h, int fd, int write)
  {
      int modes = SRT_EPOLL_ERR | (write ? SRT_EPOLL_OUT : SRT_EPOLL_IN);
      int eid = srt_epoll_create();
      if (eid < 0)
          return libsrt_neterrno(h);
      if (srt_epoll_add_usock(eid, fd, &modes) < 0) {
          srt_epoll_release(eid);
          return libsrt_neterrno(h);
      }
      return eid;
  }
  
  static int libsrt_network_wait_fd(URLContext *h, int eid, int write)
  {
      int ret, len = 1, errlen = 1;
      SRTSOCKET ready[1];
      SRTSOCKET error[1];
  
      if (write) {
          ret = srt_epoll_wait(eid, error, &errlen, ready, &len, POLLING_TIME, 0, 0, 0, 0);
      } else {
          ret = srt_epoll_wait(eid, ready, &len, error, &errlen, POLLING_TIME, 0, 0, 0, 0);
      }
      if (ret < 0) {
          if (srt_getlasterror(NULL) == SRT_ETIMEOUT)
              ret = AVERROR(EAGAIN);
          else
              ret = libsrt_neterrno(h);
      } else {
          ret = errlen ? AVERROR(EIO) : 0;
      }
      return ret;
  }
  
  /* TODO de-duplicate code from ff_network_wait_fd_timeout() */
  
  static int libsrt_network_wait_fd_timeout(URLContext *h, int eid, int write, int64_t timeout, AVIOInterruptCB *int_cb)
  {
      int ret;
      int64_t wait_start = 0;
  
      while (1) {
          if (ff_check_interrupt(int_cb))
              return AVERROR_EXIT;
          ret = libsrt_network_wait_fd(h, eid, write);
          if (ret != AVERROR(EAGAIN))
              return ret;
          if (timeout > 0) {
              if (!wait_start)
                  wait_start = av_gettime_relative();
              else if (av_gettime_relative() - wait_start > timeout)
                  return AVERROR(ETIMEDOUT);
          }
      }
  }
  
  static int libsrt_listen(int eid, int fd, const struct sockaddr *addr, socklen_t addrlen, URLContext *h, int64_t timeout)
  {
      int ret;
      int reuse = 1;
      /* Max streamid length plus an extra space for the terminating null character */
      char streamid[513];
      int streamid_len = sizeof(streamid);
      if (srt_setsockopt(fd, SOL_SOCKET, SRTO_REUSEADDR, &reuse, sizeof(reuse))) {
          av_log(h, AV_LOG_WARNING, "setsockopt(SRTO_REUSEADDR) failed\n");
      }
      if (srt_bind(fd, addr, addrlen))
          return libsrt_neterrno(h);
  
      if (srt_listen(fd, 1))
          return libsrt_neterrno(h);
  
      ret = libsrt_network_wait_fd_timeout(h, eid, 1, timeout, &h->interrupt_callback);
      if (ret < 0)
          return ret;
  
      ret = srt_accept(fd, NULL, NULL);
      if (ret < 0)
          return libsrt_neterrno(h);
      if (libsrt_socket_nonblock(ret, 1) < 0)
          av_log(h, AV_LOG_DEBUG, "libsrt_socket_nonblock failed\n");
      if (!libsrt_getsockopt(h, ret, SRTO_STREAMID, "SRTO_STREAMID", streamid, &streamid_len))
          /* Note: returned streamid_len doesn't count the terminating null character */
          av_log(h, AV_LOG_VERBOSE, "accept streamid [%s], length %d\n", streamid, streamid_len);
  
      return ret;
  }
  
  static int libsrt_listen_connect(int eid, int fd, const struct sockaddr *addr, socklen_t addrlen, int64_t timeout, URLContext *h, int will_try_next)
  {
      int ret;
  
      if (srt_connect(fd, addr, addrlen) < 0)
          return libsrt_neterrno(h);
  
      ret = libsrt_network_wait_fd_timeout(h, eid, 1, timeout, &h->interrupt_callback);
      if (ret < 0) {
          if (will_try_next) {
              av_log(h, AV_LOG_WARNING,
                     "Connection to %s failed (%s), trying next address\n",
                     h->filename, av_err2str(ret));
          } else {
              av_log(h, AV_LOG_ERROR, "Connection to %s failed: %s\n",
                     h->filename, av_err2str(ret));
          }
      }
      return ret;
  }
  
  static int libsrt_setsockopt(URLContext *h, int fd, SRT_SOCKOPT optname, const char * optnamestr, const void * optval, int optlen)
  {
      if (srt_setsockopt(fd, 0, optname, optval, optlen) < 0) {
          av_log(h, AV_LOG_ERROR, "failed to set option %s on socket: %s\n", optnamestr, srt_getlasterror_str());
          return AVERROR(EIO);
      }
      return 0;
  }
  
  /* - The "POST" options can be altered any time on a connected socket.
       They MAY have also some meaning when set prior to connecting; such
       option is SRTO_RCVSYN, which makes connect/accept call asynchronous.
       Because of that this option is treated special way in this app. */
  static int libsrt_set_options_post(URLContext *h, int fd)
  {
      SRTContext *s = h->priv_data;
  
      if ((s->inputbw >= 0 && libsrt_setsockopt(h, fd, SRTO_INPUTBW, "SRTO_INPUTBW", &s->inputbw, sizeof(s->inputbw)) < 0) ||
          (s->oheadbw >= 0 && libsrt_setsockopt(h, fd, SRTO_OHEADBW, "SRTO_OHEADBW", &s->oheadbw, sizeof(s->oheadbw)) < 0)) {
          return AVERROR(EIO);
      }
      return 0;
  }
  
  /* - The "PRE" options must be set prior to connecting and can't be altered
       on a connected socket, however if set on a listening socket, they are
       derived by accept-ed socket. */
  static int libsrt_set_options_pre(URLContext *h, int fd)
  {
      SRTContext *s = h->priv_data;
      int yes = 1;
      int latency = s->latency / 1000;
      int rcvlatency = s->rcvlatency / 1000;
      int peerlatency = s->peerlatency / 1000;
      int connect_timeout = s->connect_timeout;
  
      if ((s->mode == SRT_MODE_RENDEZVOUS && libsrt_setsockopt(h, fd, SRTO_RENDEZVOUS, "SRTO_RENDEZVOUS", &yes, sizeof(yes)) < 0) ||
          (s->transtype != SRTT_INVALID && libsrt_setsockopt(h, fd, SRTO_TRANSTYPE, "SRTO_TRANSTYPE", &s->transtype, sizeof(s->transtype)) < 0) ||
          (s->maxbw >= 0 && libsrt_setsockopt(h, fd, SRTO_MAXBW, "SRTO_MAXBW", &s->maxbw, sizeof(s->maxbw)) < 0) ||
          (s->pbkeylen >= 0 && libsrt_setsockopt(h, fd, SRTO_PBKEYLEN, "SRTO_PBKEYLEN", &s->pbkeylen, sizeof(s->pbkeylen)) < 0) ||
          (s->passphrase && libsrt_setsockopt(h, fd, SRTO_PASSPHRASE, "SRTO_PASSPHRASE", s->passphrase, strlen(s->passphrase)) < 0) ||
  #if SRT_VERSION_VALUE >= 0x010302
  #if SRT_VERSION_VALUE >= 0x010401
          (s->enforced_encryption >= 0 && libsrt_setsockopt(h, fd, SRTO_ENFORCEDENCRYPTION, "SRTO_ENFORCEDENCRYPTION", &s->enforced_encryption, sizeof(s->enforced_encryption)) < 0) ||
  #else
          /* SRTO_STRICTENC == SRTO_ENFORCEDENCRYPTION (53), but for compatibility, we used SRTO_STRICTENC */
          (s->enforced_encryption >= 0 && libsrt_setsockopt(h, fd, SRTO_STRICTENC, "SRTO_STRICTENC", &s->enforced_encryption, sizeof(s->enforced_encryption)) < 0) ||
  #endif
          (s->kmrefreshrate >= 0 && libsrt_setsockopt(h, fd, SRTO_KMREFRESHRATE, "SRTO_KMREFRESHRATE", &s->kmrefreshrate, sizeof(s->kmrefreshrate)) < 0) ||
          (s->kmpreannounce >= 0 && libsrt_setsockopt(h, fd, SRTO_KMPREANNOUNCE, "SRTO_KMPREANNOUNCE", &s->kmpreannounce, sizeof(s->kmpreannounce)) < 0) ||
  #endif
          (s->mss >= 0 && libsrt_setsockopt(h, fd, SRTO_MSS, "SRTO_MSS", &s->mss, sizeof(s->mss)) < 0) ||
          (s->ffs >= 0 && libsrt_setsockopt(h, fd, SRTO_FC, "SRTO_FC", &s->ffs, sizeof(s->ffs)) < 0) ||
          (s->ipttl >= 0 && libsrt_setsockopt(h, fd, SRTO_IPTTL, "SRTO_IPTTL", &s->ipttl, sizeof(s->ipttl)) < 0) ||
          (s->iptos >= 0 && libsrt_setsockopt(h, fd, SRTO_IPTOS, "SRTO_IPTOS", &s->iptos, sizeof(s->iptos)) < 0) ||
          (s->latency >= 0 && libsrt_setsockopt(h, fd, SRTO_LATENCY, "SRTO_LATENCY", &latency, sizeof(latency)) < 0) ||
          (s->rcvlatency >= 0 && libsrt_setsockopt(h, fd, SRTO_RCVLATENCY, "SRTO_RCVLATENCY", &rcvlatency, sizeof(rcvlatency)) < 0) ||
          (s->peerlatency >= 0 && libsrt_setsockopt(h, fd, SRTO_PEERLATENCY, "SRTO_PEERLATENCY", &peerlatency, sizeof(peerlatency)) < 0) ||
          (s->tlpktdrop >= 0 && libsrt_setsockopt(h, fd, SRTO_TLPKTDROP, "SRTO_TLPKTDROP", &s->tlpktdrop, sizeof(s->tlpktdrop)) < 0) ||
          (s->nakreport >= 0 && libsrt_setsockopt(h, fd, SRTO_NAKREPORT, "SRTO_NAKREPORT", &s->nakreport, sizeof(s->nakreport)) < 0) ||
          (connect_timeout >= 0 && libsrt_setsockopt(h, fd, SRTO_CONNTIMEO, "SRTO_CONNTIMEO", &connect_timeout, sizeof(connect_timeout)) <0 ) ||
          (s->sndbuf >= 0 && libsrt_setsockopt(h, fd, SRTO_SNDBUF, "SRTO_SNDBUF", &s->sndbuf, sizeof(s->sndbuf)) < 0) ||
          (s->rcvbuf >= 0 && libsrt_setsockopt(h, fd, SRTO_RCVBUF, "SRTO_RCVBUF", &s->rcvbuf, sizeof(s->rcvbuf)) < 0) ||
          (s->lossmaxttl >= 0 && libsrt_setsockopt(h, fd, SRTO_LOSSMAXTTL, "SRTO_LOSSMAXTTL", &s->lossmaxttl, sizeof(s->lossmaxttl)) < 0) ||
          (s->minversion >= 0 && libsrt_setsockopt(h, fd, SRTO_MINVERSION, "SRTO_MINVERSION", &s->minversion, sizeof(s->minversion)) < 0) ||
          (s->streamid && libsrt_setsockopt(h, fd, SRTO_STREAMID, "SRTO_STREAMID", s->streamid, strlen(s->streamid)) < 0) ||
  #if SRT_VERSION_VALUE >= 0x010401
          (s->smoother && libsrt_setsockopt(h, fd, SRTO_CONGESTION, "SRTO_CONGESTION", s->smoother, strlen(s->smoother)) < 0) ||
  #else
          (s->smoother && libsrt_setsockopt(h, fd, SRTO_SMOOTHER, "SRTO_SMOOTHER", s->smoother, strlen(s->smoother)) < 0) ||
  #endif
          (s->messageapi >= 0 && libsrt_setsockopt(h, fd, SRTO_MESSAGEAPI, "SRTO_MESSAGEAPI", &s->messageapi, sizeof(s->messageapi)) < 0) ||
          (s->payload_size >= 0 && libsrt_setsockopt(h, fd, SRTO_PAYLOADSIZE, "SRTO_PAYLOADSIZE", &s->payload_size, sizeof(s->payload_size)) < 0) ||
          ((h->flags & AVIO_FLAG_WRITE) && libsrt_setsockopt(h, fd, SRTO_SENDER, "SRTO_SENDER", &yes, sizeof(yes)) < 0) ||
          (s->tsbpd >= 0 && libsrt_setsockopt(h, fd, SRTO_TSBPDMODE, "SRTO_TSBPDMODE", &s->tsbpd, sizeof(s->tsbpd)) < 0)) {
          return AVERROR(EIO);
      }
  
      if (s->linger >= 0) {
          struct linger lin;
          lin.l_linger = s->linger;
          lin.l_onoff  = lin.l_linger > 0 ? 1 : 0;
          if (libsrt_setsockopt(h, fd, SRTO_LINGER, "SRTO_LINGER", &lin, sizeof(lin)) < 0)
              return AVERROR(EIO);
      }
      return 0;
  }
  
  
  static int libsrt_setup(URLContext *h, const char *uri, int flags)
  {
      struct addrinfo hints = { 0 }, *ai, *cur_ai;
      int port, fd;
      SRTContext *s = h->priv_data;
      const char *p;
      char buf[256];
      int ret;
      char hostname[1024],proto[1024],path[1024];
      char portstr[10];
      int64_t open_timeout = 0;
      int eid, write_eid;
  
      av_url_split(proto, sizeof(proto), NULL, 0, hostname, sizeof(hostname),
          &port, path, sizeof(path), uri);
      if (strcmp(proto, "srt"))
          return AVERROR(EINVAL);
      if (port <= 0 || port >= 65536) {
          av_log(h, AV_LOG_ERROR, "Port missing in uri\n");
          return AVERROR(EINVAL);
      }
      p = strchr(uri, '?');
      if (p) {
          if (av_find_info_tag(buf, sizeof(buf), "timeout", p)) {
              s->rw_timeout = strtol(buf, NULL, 10);
          }
          if (av_find_info_tag(buf, sizeof(buf), "listen_timeout", p)) {
              s->listen_timeout = strtol(buf, NULL, 10);
          }
      }
      if (s->rw_timeout >= 0) {
          open_timeout = h->rw_timeout = s->rw_timeout;
      }
      hints.ai_family = AF_UNSPEC;
      hints.ai_socktype = SOCK_DGRAM;
      snprintf(portstr, sizeof(portstr), "%d", port);
      if (s->mode == SRT_MODE_LISTENER)
          hints.ai_flags |= AI_PASSIVE;
      ret = getaddrinfo(hostname[0] ? hostname : NULL, portstr, &hints, &ai);
      if (ret) {
          av_log(h, AV_LOG_ERROR,
                 "Failed to resolve hostname %s: %s\n",
                 hostname, gai_strerror(ret));
          return AVERROR(EIO);
      }
  
      cur_ai = ai;
  
   restart:
  
      fd = srt_socket(cur_ai->ai_family, cur_ai->ai_socktype, 0);
      if (fd < 0) {
          ret = libsrt_neterrno(h);
          goto fail;
      }
  
      if ((ret = libsrt_set_options_pre(h, fd)) < 0) {
          goto fail;
      }
  
      /* Set the socket's send or receive buffer sizes, if specified.
         If unspecified or setting fails, system default is used. */
      if (s->recv_buffer_size > 0) {
          srt_setsockopt(fd, SOL_SOCKET, SRTO_UDP_RCVBUF, &s->recv_buffer_size, sizeof (s->recv_buffer_size));
      }
      if (s->send_buffer_size > 0) {
          srt_setsockopt(fd, SOL_SOCKET, SRTO_UDP_SNDBUF, &s->send_buffer_size, sizeof (s->send_buffer_size));
      }
      if (libsrt_socket_nonblock(fd, 1) < 0)
          av_log(h, AV_LOG_DEBUG, "libsrt_socket_nonblock failed\n");
  
      ret = write_eid = libsrt_epoll_create(h, fd, 1);
      if (ret < 0)
          goto fail1;
      if (s->mode == SRT_MODE_LISTENER) {
          // multi-client
          ret = libsrt_listen(write_eid, fd, cur_ai->ai_addr, cur_ai->ai_addrlen, h, s->listen_timeout);
          srt_epoll_release(write_eid);
          if (ret < 0)
              goto fail1;
          srt_close(fd);
          fd = ret;
      } else {
          if (s->mode == SRT_MODE_RENDEZVOUS) {
              if (srt_bind(fd, cur_ai->ai_addr, cur_ai->ai_addrlen)) {
                  ret = libsrt_neterrno(h);
                  srt_epoll_release(write_eid);
                  goto fail1;
              }
          }
  
          ret = libsrt_listen_connect(write_eid, fd, cur_ai->ai_addr, cur_ai->ai_addrlen,
                                      open_timeout, h, !!cur_ai->ai_next);
          srt_epoll_release(write_eid);
          if (ret < 0) {
              if (ret == AVERROR_EXIT)
                  goto fail1;
              else
                  goto fail;
          }
      }
      if ((ret = libsrt_set_options_post(h, fd)) < 0) {
          goto fail;
      }
  
      if (flags & AVIO_FLAG_WRITE) {
          int packet_size = 0;
          int optlen = sizeof(packet_size);
          ret = libsrt_getsockopt(h, fd, SRTO_PAYLOADSIZE, "SRTO_PAYLOADSIZE", &packet_size, &optlen);
          if (ret < 0)
              goto fail1;
          if (packet_size > 0)
              h->max_packet_size = packet_size;
      }
  
      ret = eid = libsrt_epoll_create(h, fd, flags & AVIO_FLAG_WRITE);
      if (eid < 0)
          goto fail1;
  
      h->is_streamed = 1;
      s->fd = fd;
      s->eid = eid;
  
      freeaddrinfo(ai);
      return 0;
  
   fail:
      if (cur_ai->ai_next) {
          /* Retry with the next sockaddr */
          cur_ai = cur_ai->ai_next;
          if (fd >= 0)
              srt_close(fd);
          ret = 0;
          goto restart;
      }
   fail1:
      if (fd >= 0)
          srt_close(fd);
      freeaddrinfo(ai);
      return ret;
  }
  
  static int libsrt_open(URLContext *h, const char *uri, int flags)
  {
      SRTContext *s = h->priv_data;
      const char * p;
      char buf[256];
      int ret = 0;
  
      if (srt_startup() < 0) {
          return AVERROR_UNKNOWN;
      }
  
      /* SRT options (srt/srt.h) */
      p = strchr(uri, '?');
      if (p) {
          if (av_find_info_tag(buf, sizeof(buf), "maxbw", p)) {
              s->maxbw = strtoll(buf, NULL, 0);
          }
          if (av_find_info_tag(buf, sizeof(buf), "pbkeylen", p)) {
              s->pbkeylen = strtol(buf, NULL, 10);
          }
          if (av_find_info_tag(buf, sizeof(buf), "passphrase", p)) {
              av_freep(&s->passphrase);
              s->passphrase = av_strndup(buf, strlen(buf));
          }
  #if SRT_VERSION_VALUE >= 0x010302
          if (av_find_info_tag(buf, sizeof(buf), "enforced_encryption", p)) {
              s->enforced_encryption = strtol(buf, NULL, 10);
          }
          if (av_find_info_tag(buf, sizeof(buf), "kmrefreshrate", p)) {
              s->kmrefreshrate = strtol(buf, NULL, 10);
          }
          if (av_find_info_tag(buf, sizeof(buf), "kmpreannounce", p)) {
              s->kmpreannounce = strtol(buf, NULL, 10);
          }
  #endif
          if (av_find_info_tag(buf, sizeof(buf), "mss", p)) {
              s->mss = strtol(buf, NULL, 10);
          }
          if (av_find_info_tag(buf, sizeof(buf), "ffs", p)) {
              s->ffs = strtol(buf, NULL, 10);
          }
          if (av_find_info_tag(buf, sizeof(buf), "ipttl", p)) {
              s->ipttl = strtol(buf, NULL, 10);
          }
          if (av_find_info_tag(buf, sizeof(buf), "iptos", p)) {
              s->iptos = strtol(buf, NULL, 10);
          }
          if (av_find_info_tag(buf, sizeof(buf), "inputbw", p)) {
              s->inputbw = strtoll(buf, NULL, 10);
          }
          if (av_find_info_tag(buf, sizeof(buf), "oheadbw", p)) {
              s->oheadbw = strtoll(buf, NULL, 10);
          }
          if (av_find_info_tag(buf, sizeof(buf), "latency", p)) {
              s->latency = strtol(buf, NULL, 10);
          }
          if (av_find_info_tag(buf, sizeof(buf), "tsbpddelay", p)) {
              s->latency = strtol(buf, NULL, 10);
          }
          if (av_find_info_tag(buf, sizeof(buf), "rcvlatency", p)) {
              s->rcvlatency = strtol(buf, NULL, 10);
          }
          if (av_find_info_tag(buf, sizeof(buf), "peerlatency", p)) {
              s->peerlatency = strtol(buf, NULL, 10);
          }
          if (av_find_info_tag(buf, sizeof(buf), "tlpktdrop", p)) {
              s->tlpktdrop = strtol(buf, NULL, 10);
          }
          if (av_find_info_tag(buf, sizeof(buf), "nakreport", p)) {
              s->nakreport = strtol(buf, NULL, 10);
          }
          if (av_find_info_tag(buf, sizeof(buf), "connect_timeout", p)) {
              s->connect_timeout = strtol(buf, NULL, 10);
          }
          if (av_find_info_tag(buf, sizeof(buf), "payload_size", p) ||
              av_find_info_tag(buf, sizeof(buf), "pkt_size", p)) {
              s->payload_size = strtol(buf, NULL, 10);
          }
          if (av_find_info_tag(buf, sizeof(buf), "mode", p)) {
              if (!strcmp(buf, "caller")) {
                  s->mode = SRT_MODE_CALLER;
              } else if (!strcmp(buf, "listener")) {
                  s->mode = SRT_MODE_LISTENER;
              } else if (!strcmp(buf, "rendezvous")) {
                  s->mode = SRT_MODE_RENDEZVOUS;
              } else {
                  ret = AVERROR(EINVAL);
                  goto err;
              }
          }
          if (av_find_info_tag(buf, sizeof(buf), "sndbuf", p)) {
              s->sndbuf = strtol(buf, NULL, 10);
          }
          if (av_find_info_tag(buf, sizeof(buf), "rcvbuf", p)) {
              s->rcvbuf = strtol(buf, NULL, 10);
          }
          if (av_find_info_tag(buf, sizeof(buf), "lossmaxttl", p)) {
              s->lossmaxttl = strtol(buf, NULL, 10);
          }
          if (av_find_info_tag(buf, sizeof(buf), "minversion", p)) {
              s->minversion = strtol(buf, NULL, 0);
          }
          if (av_find_info_tag(buf, sizeof(buf), "streamid", p)) {
              av_freep(&s->streamid);
              s->streamid = av_strdup(buf);
              if (!s->streamid) {
                  ret = AVERROR(ENOMEM);
                  goto err;
              }
          }
          if (av_find_info_tag(buf, sizeof(buf), "smoother", p)) {
              av_freep(&s->smoother);
              s->smoother = av_strdup(buf);
              if(!s->smoother) {
                  ret = AVERROR(ENOMEM);
                  goto err;
              }
          }
          if (av_find_info_tag(buf, sizeof(buf), "messageapi", p)) {
              s->messageapi = strtol(buf, NULL, 10);
          }
          if (av_find_info_tag(buf, sizeof(buf), "transtype", p)) {
              if (!strcmp(buf, "live")) {
                  s->transtype = SRTT_LIVE;
              } else if (!strcmp(buf, "file")) {
                  s->transtype = SRTT_FILE;
              } else {
                  ret = AVERROR(EINVAL);
                  goto err;
              }
          }
          if (av_find_info_tag(buf, sizeof(buf), "linger", p)) {
              s->linger = strtol(buf, NULL, 10);
          }
      }
      ret = libsrt_setup(h, uri, flags);
      if (ret < 0)
          goto err;
      return 0;
  
  err:
      av_freep(&s->smoother);
      av_freep(&s->streamid);
      srt_cleanup();
      return ret;
  }
  
  static int libsrt_read(URLContext *h, uint8_t *buf, int size)
  {
      SRTContext *s = h->priv_data;
      int ret;
  
      if (!(h->flags & AVIO_FLAG_NONBLOCK)) {
          ret = libsrt_network_wait_fd_timeout(h, s->eid, 0, h->rw_timeout, &h->interrupt_callback);
          if (ret)
              return ret;
      }
  
      ret = srt_recvmsg(s->fd, buf, size);
      if (ret < 0) {
          ret = libsrt_neterrno(h);
      }
  
      return ret;
  }
  
  static int libsrt_write(URLContext *h, const uint8_t *buf, int size)
  {
      SRTContext *s = h->priv_data;
      int ret;
  
      if (!(h->flags & AVIO_FLAG_NONBLOCK)) {
          ret = libsrt_network_wait_fd_timeout(h, s->eid, 1, h->rw_timeout, &h->interrupt_callback);
          if (ret)
              return ret;
      }
  
      ret = srt_sendmsg(s->fd, buf, size, -1, 1);
      if (ret < 0) {
          ret = libsrt_neterrno(h);
      }
  
      return ret;
  }
  
  static int libsrt_close(URLContext *h)
  {
      SRTContext *s = h->priv_data;
  
      srt_epoll_release(s->eid);
      srt_close(s->fd);
  
      srt_cleanup();
  
      return 0;
  }
  
  static const AVClass libsrt_class = {
      .class_name = "libsrt",
      .item_name  = av_default_item_name,
      .option     = libsrt_options,
      .version    = LIBAVUTIL_VERSION_INT,
  };
  
  const URLProtocol ff_libsrt_protocol = {
      .name                = "srt",
      .url_open            = libsrt_open,
      .url_read            = libsrt_read,
      .url_write           = libsrt_write,
      .url_close           = libsrt_close,
      .priv_data_size      = sizeof(SRTContext),
      .flags               = URL_PROTOCOL_FLAG_NETWORK,
      .priv_data_class     = &libsrt_class,
  };
  