/*

 * TCP protocol

 * Copyright (c) 2002 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 "avformat.h"

#include "libavutil/avassert.h"

#include "libavutil/mem.h"

#include "libavutil/parseutils.h"

#include "libavutil/opt.h"

#include "libavutil/time.h"

#include "internal.h"

#include "network.h"

#include "os_support.h"

#include "url.h"

#if HAVE_POLL_H

#include <poll.h>

#endif

typedef struct TCPContext {

    const AVClass *class;

    int fd;

    int listen;

    char *local_port;

    char *local_addr;

    int open_timeout;

    int rw_timeout;

    int listen_timeout;

    int recv_buffer_size;

    int send_buffer_size;

    int tcp_nodelay;

    int tcp_keepalive;

#if !HAVE_WINSOCK2_H

    int tcp_mss;

#endif /* !HAVE_WINSOCK2_H */

} TCPContext;

#define OFFSET(x) offsetof(TCPContext, x)

#define D AV_OPT_FLAG_DECODING_PARAM

#define E AV_OPT_FLAG_ENCODING_PARAM

static const AVOption options[] = {

    { "listen",          "Listen for incoming connections",  OFFSET(listen),         AV_OPT_TYPE_INT, { .i64 = 0 },     0,       2,       .flags = D|E },

    { "local_port",      "Local port",                                         OFFSET(local_port),     AV_OPT_TYPE_STRING, { .str = NULL },     0,       0, .flags = D|E },

    { "local_addr",      "Local address",                                      OFFSET(local_addr),     AV_OPT_TYPE_STRING, { .str = NULL },     0,       0, .flags = D|E },

    { "timeout",     "set timeout (in microseconds) of socket I/O operations", OFFSET(rw_timeout),     AV_OPT_TYPE_INT, { .i64 = -1 },         -1, INT_MAX, .flags = D|E },

    { "listen_timeout",  "Connection awaiting timeout (in milliseconds)",      OFFSET(listen_timeout), AV_OPT_TYPE_INT, { .i64 = -1 },         -1, INT_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 },

    { "tcp_nodelay", "Use TCP_NODELAY to disable nagle's algorithm",           OFFSET(tcp_nodelay), AV_OPT_TYPE_BOOL, { .i64 = 0 },             0, 1, .flags = D|E },

    { "tcp_keepalive", "Use TCP keepalive to detect dead connections and keep long-lived connections active.",           OFFSET(tcp_keepalive), AV_OPT_TYPE_BOOL, { .i64 = 0 },             0, 1, .flags = D|E },

#if !HAVE_WINSOCK2_H

    { "tcp_mss",     "Maximum segment size for outgoing TCP packets",          OFFSET(tcp_mss),     AV_OPT_TYPE_INT, { .i64 = -1 },         -1, INT_MAX, .flags = D|E },

#endif /* !HAVE_WINSOCK2_H */

    { NULL }

};

static const AVClass tcp_class = {

    .class_name = "tcp",

    .item_name  = av_default_item_name,

    .option     = options,

    .version    = LIBAVUTIL_VERSION_INT,

};

static int customize_fd(void *ctx, int fd, int family)

{

    TCPContext *s = ctx;

    if (s->local_addr || s->local_port) {

        struct addrinfo hints = { 0 }, *ai, *cur_ai;

        int ret;

        hints.ai_family = family;

        hints.ai_socktype = SOCK_STREAM;

        ret = getaddrinfo(s->local_addr, s->local_port, &hints, &ai);

        if (ret) {

            av_log(ctx, AV_LOG_ERROR,

               "Failed to getaddrinfo local addr: %s port: %s err: %s\n",

               s->local_addr, s->local_port, gai_strerror(ret));

            return ret;

        }

        cur_ai = ai;

        while (cur_ai) {

            ret = bind(fd, (struct sockaddr *)cur_ai->ai_addr, (int)cur_ai->ai_addrlen);

            if (ret)

                cur_ai = cur_ai->ai_next;

            else

                break;

        }

        freeaddrinfo(ai);

        if (ret) {

            ff_log_net_error(ctx, AV_LOG_ERROR, "bind local failed");

            return ret;

        }

    }

    /* 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) {

        if (setsockopt (fd, SOL_SOCKET, SO_RCVBUF, &s->recv_buffer_size, sizeof (s->recv_buffer_size))) {

            ff_log_net_error(ctx, AV_LOG_WARNING, "setsockopt(SO_RCVBUF)");

        }

    }

    if (s->send_buffer_size > 0) {

        if (setsockopt (fd, SOL_SOCKET, SO_SNDBUF, &s->send_buffer_size, sizeof (s->send_buffer_size))) {

            ff_log_net_error(ctx, AV_LOG_WARNING, "setsockopt(SO_SNDBUF)");

        }

    }

    if (s->tcp_nodelay > 0) {

        if (setsockopt (fd, IPPROTO_TCP, TCP_NODELAY, &s->tcp_nodelay, sizeof (s->tcp_nodelay))) {

            ff_log_net_error(ctx, AV_LOG_WARNING, "setsockopt(TCP_NODELAY)");

        }

    }

    if (s->tcp_keepalive > 0) {

        if (setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &s->tcp_keepalive, sizeof(s->tcp_keepalive))) {

            ff_log_net_error(ctx, AV_LOG_WARNING, "setsockopt(SO_KEEPALIVE)");

        }

    }

#if !HAVE_WINSOCK2_H

    if (s->tcp_mss > 0) {

        if (setsockopt (fd, IPPROTO_TCP, TCP_MAXSEG, &s->tcp_mss, sizeof (s->tcp_mss))) {

            ff_log_net_error(ctx, AV_LOG_WARNING, "setsockopt(TCP_MAXSEG)");

        }

    }

#endif /* !HAVE_WINSOCK2_H */

    return 0;

}

/* return non zero if error */

static int tcp_open(URLContext *h, const char *uri, int flags)

{

    struct addrinfo hints = { 0 }, *ai, *cur_ai;

    int port, fd = -1;

    TCPContext *s = h->priv_data;

    const char *p;

    int ret;

    char hostname[1024],proto[1024],path[1024];

    char portstr[10];

    s->open_timeout = 5000000;

    av_url_split(proto, sizeof(proto), NULL, 0, hostname, sizeof(hostname),

        &port, path, sizeof(path), uri);

    if (strcmp(proto, "tcp"))

        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) {

        int ret = ff_parse_opts_from_query_string(s, p, 1);

        if (ret < 0)

            return ret;

    }

    if (s->rw_timeout >= 0) {

        s->open_timeout =

        h->rw_timeout   = s->rw_timeout;

    }

    hints.ai_family = AF_UNSPEC;

    hints.ai_socktype = SOCK_STREAM;

    snprintf(portstr, sizeof(portstr), "%d", port);

    if (s->listen)

        hints.ai_flags |= AI_PASSIVE;

    if (!hostname[0])

        ret = getaddrinfo(NULL, portstr, &hints, &ai);

    else

        ret = getaddrinfo(hostname, 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;

#if HAVE_STRUCT_SOCKADDR_IN6

    // workaround for IOS9 getaddrinfo in IPv6 only network use hardcode IPv4 address can not resolve port number.

    if (cur_ai->ai_family == AF_INET6){

        struct sockaddr_in6 * sockaddr_v6 = (struct sockaddr_in6 *)cur_ai->ai_addr;

        if (!sockaddr_v6->sin6_port){

            sockaddr_v6->sin6_port = htons(port);

        }

    }

#endif

    if (s->listen > 0) {

        while (cur_ai && fd < 0) {

            fd = ff_socket(cur_ai->ai_family,

                           cur_ai->ai_socktype,

                           cur_ai->ai_protocol, h);

            if (fd < 0) {

                ret = ff_neterrno();

                cur_ai = cur_ai->ai_next;

            }

        }

        if (fd < 0)

            goto fail1;

        customize_fd(s, fd, cur_ai->ai_family);

    }

    if (s->listen == 2) {

        // multi-client

        if ((ret = ff_listen(fd, cur_ai->ai_addr, cur_ai->ai_addrlen, h)) < 0)

            goto fail1;

    } else if (s->listen == 1) {

        // single client

        if ((ret = ff_listen_bind(fd, cur_ai->ai_addr, cur_ai->ai_addrlen,

                                  s->listen_timeout, h)) < 0)

            goto fail1;

        // Socket descriptor already closed here. Safe to overwrite to client one.

        fd = ret;

    } else {

        ret = ff_connect_parallel(ai, s->open_timeout / 1000, 3, h, &fd, customize_fd, s);

        if (ret < 0)

            goto fail1;

    }

    h->is_streamed = 1;

    s->fd = fd;

    freeaddrinfo(ai);

    return 0;

 fail1:

    if (fd >= 0)

        closesocket(fd);

    freeaddrinfo(ai);

    return ret;

}

static int tcp_accept(URLContext *s, URLContext **c)

{

    TCPContext *sc = s->priv_data;

    TCPContext *cc;

    int ret;

    av_assert0(sc->listen);

    if ((ret = ffurl_alloc(c, s->filename, s->flags, &s->interrupt_callback)) < 0)

        return ret;

    cc = (*c)->priv_data;

    ret = ff_accept(sc->fd, sc->listen_timeout, s);

    if (ret < 0) {

        ffurl_closep(c);

        return ret;

    }

    cc->fd = ret;

    return 0;

}

static int tcp_read(URLContext *h, uint8_t *buf, int size)

{

    TCPContext *s = h->priv_data;

    int ret;

    if (!(h->flags & AVIO_FLAG_NONBLOCK)) {

        ret = ff_network_wait_fd_timeout(s->fd, 0, h->rw_timeout, &h->interrupt_callback);

        if (ret)

            return ret;

    }

    ret = recv(s->fd, buf, size, 0);

    if (ret == 0)

        return AVERROR_EOF;

    return ret < 0 ? ff_neterrno() : ret;

}

static int tcp_write(URLContext *h, const uint8_t *buf, int size)

{

    TCPContext *s = h->priv_data;

    int ret;

    if (!(h->flags & AVIO_FLAG_NONBLOCK)) {

        ret = ff_network_wait_fd_timeout(s->fd, 1, h->rw_timeout, &h->interrupt_callback);

        if (ret)

            return ret;

    }

    ret = send(s->fd, buf, size, MSG_NOSIGNAL);

    return ret < 0 ? ff_neterrno() : ret;

}

static int tcp_shutdown(URLContext *h, int flags)

{

    TCPContext *s = h->priv_data;

    int how;

    if (flags & AVIO_FLAG_WRITE && flags & AVIO_FLAG_READ) {

        how = SHUT_RDWR;

    } else if (flags & AVIO_FLAG_WRITE) {

        how = SHUT_WR;

    } else {

        how = SHUT_RD;

    }

    return shutdown(s->fd, how);

}

static int tcp_close(URLContext *h)

{

    TCPContext *s = h->priv_data;

    closesocket(s->fd);

    return 0;

}

static int tcp_get_file_handle(URLContext *h)

{

    TCPContext *s = h->priv_data;

    return s->fd;

}

static int tcp_get_window_size(URLContext *h)

{

    TCPContext *s = h->priv_data;

    int avail;

    socklen_t avail_len = sizeof(avail);

#if HAVE_WINSOCK2_H

    /* SO_RCVBUF with winsock only reports the actual TCP window size when

    auto-tuning has been disabled via setting SO_RCVBUF */

    if (s->recv_buffer_size < 0) {

        return AVERROR(ENOSYS);

    }

#endif

    if (getsockopt(s->fd, SOL_SOCKET, SO_RCVBUF, &avail, &avail_len)) {

        return ff_neterrno();

    }

    return avail;

}

const URLProtocol ff_tcp_protocol = {

    .name                = "tcp",

    .url_open            = tcp_open,

    .url_accept          = tcp_accept,

    .url_read            = tcp_read,

    .url_write           = tcp_write,

    .url_close           = tcp_close,

    .url_get_file_handle = tcp_get_file_handle,

    .url_get_short_seek  = tcp_get_window_size,

    .url_shutdown        = tcp_shutdown,

    .priv_data_size      = sizeof(TCPContext),

    .flags               = URL_PROTOCOL_FLAG_NETWORK,

    .priv_data_class     = &tcp_class,

};