/*

 * Copyright (c) 2007 The FFmpeg Project

 *

 * 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 <string.h>

#include "config.h"

#include "config_components.h"

#include "libavutil/attributes.h"

#if CONFIG_TLS_PROTOCOL && CONFIG_OPENSSL

#include <openssl/opensslv.h>

#endif

#include <fcntl.h>

#if HAVE_EVENTFD

#include <sys/eventfd.h>

#endif

#include "network.h"

#include "tls.h"

#include "url.h"

#include "libavutil/avassert.h"

#include "libavutil/mem.h"

#include "libavutil/time.h"

int ff_tls_init(void)

{

#if CONFIG_TLS_PROTOCOL

#if CONFIG_GNUTLS

    ff_gnutls_init();

#endif

#endif

    return 0;

}

void ff_tls_deinit(void)

{

#if CONFIG_TLS_PROTOCOL

#if CONFIG_GNUTLS

    ff_gnutls_deinit();

#endif

#endif

}

/**

 * Initialize the network subsystem. On Windows, this calls WSAStartup().

 *

 * @return 0 on success, a negative AVERROR code on failure.

 */

int ff_network_init(void)

{

#if HAVE_WINSOCK2_H

    WSADATA wsaData;

    if (WSAStartup(MAKEWORD(1,1), &wsaData))

        return AVERROR(EIO);

#endif

    return 0;

}

int ff_network_wait_fd(int fd, int write)

{

    int ev = write ? POLLOUT : POLLIN;

    struct pollfd p = { .fd = fd, .events = ev, .revents = 0 };

    int ret;

    ret = poll(&p, 1, POLLING_TIME);

    return ret < 0 ? ff_neterrno() : p.revents & (ev | POLLERR | POLLHUP) ? 0 : AVERROR(EAGAIN);

}

int ff_network_wait_fd_timeout(int fd, 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 = ff_network_wait_fd(fd, 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);

        }

    }

}

int ff_network_wakeup_open(FFNetWakeup *w)

{

#if HAVE_WINSOCK2_H

    /* select() and WSAPoll() only accept sockets, so use a datagram socket

     * connected to itself: sending a datagram to it makes it readable.

     */

    struct sockaddr_in addr = { .sin_family = AF_INET };

    socklen_t len = sizeof(addr);

    int ret, fd = ff_socket(AF_INET, SOCK_DGRAM, 0, NULL);

    if (fd < 0)

        return ff_neterrno();

    addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);

    if (bind(fd, (struct sockaddr *)&addr, sizeof(addr)) < 0 ||

        getsockname(fd, (struct sockaddr *)&addr, &len) < 0 ||

        connect(fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {

        ret = ff_neterrno();

        closesocket(fd);

        return ret;

    }

    w->rfd = w->wfd = fd;

#elif HAVE_EVENTFD

    int fd = eventfd(0, EFD_CLOEXEC);

    if (fd < 0)

        return AVERROR(errno);

    w->rfd = w->wfd = fd;

#else

    int fds[2];

    if (pipe(fds) < 0)

        return AVERROR(errno);

#if HAVE_FCNTL

    for (int i = 0; i < 2; i++) {

        if (fcntl(fds[i], F_SETFD, FD_CLOEXEC) < 0) {

            int ret = AVERROR(errno);

            closesocket(fds[0]);

            closesocket(fds[1]);

            return ret;

        }

    }

#endif

    w->rfd = fds[0];

    w->wfd = fds[1];

#endif

    atomic_init(&w->signaled, 0);

    return 0;

}

int ff_network_wakeup_signal(FFNetWakeup *w)

{

    /* An eventfd only accepts 8-byte writes; a pipe or a socket takes any

     * payload, so the same value serves every channel type.

     */

    const uint64_t one = 1;

    int ret;

    /* wfd is blocking; writing at most once keeps the write from blocking.

     * The flag publishes no other data, so relaxed ordering is enough.

     */

    if (atomic_exchange_explicit(&w->signaled, 1, memory_order_relaxed))

        return 0;

#if HAVE_WINSOCK2_H

    ret = send(w->wfd, (const char *)&one, sizeof(one), 0);

#else

    ret = write(w->wfd, &one, sizeof(one));

#endif

    return ret < 0 ? ff_neterrno() : 0;

}

void ff_network_wakeup_close(FFNetWakeup *w)

{

    if (w->wfd != w->rfd)

        closesocket(w->wfd);

    closesocket(w->rfd);

    w->rfd = w->wfd = -1;

}

int ff_network_wait_fd_wakeup(int fd, int write, int timeout_ms,

                              const FFNetWakeup *w)

{

    int ev = write ? POLLOUT : POLLIN;

    struct pollfd p[2] = {

        { .fd = w->rfd, .events = POLLIN },

        { .fd = fd,     .events = ev },

    };

    int ret;

    /* Return without polling once signaled. This also ends the wait when

     * the write in ff_network_wakeup_signal() failed and rfd never became

     * readable.

     */

    if (atomic_load_explicit(&w->signaled, memory_order_relaxed))

        return AVERROR_EXIT;

    ret = poll(p, 2, timeout_ms);

    if (ret < 0)

        return ff_neterrno();

    if (p[0].revents & POLLIN)

        return AVERROR_EXIT;

    return p[1].revents & (ev | POLLERR | POLLHUP) ? 0 : AVERROR(EAGAIN);

}

int ff_network_sleep_interruptible(int64_t timeout, AVIOInterruptCB *int_cb)

{

    int64_t wait_start = av_gettime_relative();

    while (1) {

        int64_t time_left;

        if (ff_check_interrupt(int_cb))

            return AVERROR_EXIT;

        time_left = timeout - (av_gettime_relative() - wait_start);

        if (time_left <= 0)

            return AVERROR(ETIMEDOUT);

        av_usleep(FFMIN(time_left, POLLING_TIME * 1000));

    }

}

void ff_network_close(void)

{

#if HAVE_WINSOCK2_H

    WSACleanup();

#endif

}

#if HAVE_WINSOCK2_H

int ff_neterrno(void)

{

    int err = WSAGetLastError();

    switch (err) {

    case WSAEWOULDBLOCK:

        return AVERROR(EAGAIN);

    case WSAEINTR:

        return AVERROR(EINTR);

    case WSAEPROTONOSUPPORT:

        return AVERROR(EPROTONOSUPPORT);

    case WSAETIMEDOUT:

        return AVERROR(ETIMEDOUT);

    case WSAECONNREFUSED:

        return AVERROR(ECONNREFUSED);

    case WSAEINPROGRESS:

        return AVERROR(EINPROGRESS);

    }

    return -err;

}

#endif

int ff_is_multicast_address(struct sockaddr *addr)

{

    if (addr->sa_family == AF_INET) {

        return IN_MULTICAST(ntohl(((struct sockaddr_in *)addr)->sin_addr.s_addr));

    }

#if HAVE_STRUCT_SOCKADDR_IN6

    if (addr->sa_family == AF_INET6) {

        return IN6_IS_ADDR_MULTICAST(&((struct sockaddr_in6 *)addr)->sin6_addr);

    }

#endif

    return 0;

}

static int ff_poll_interrupt(struct pollfd *p, nfds_t nfds, int timeout,

                             AVIOInterruptCB *cb)

{

    int runs = timeout / POLLING_TIME;

    int ret = 0;

    do {

        if (ff_check_interrupt(cb))

            return AVERROR_EXIT;

        ret = poll(p, nfds, POLLING_TIME);

        if (ret != 0) {

            if (ret < 0)

                ret = ff_neterrno();

            if (ret == AVERROR(EINTR))

                continue;

            break;

        }

    } while (timeout <= 0 || runs-- > 0);

    if (!ret)

        return AVERROR(ETIMEDOUT);

    return ret;

}

int ff_socket(int af, int type, int proto, void *logctx)

{

    int fd;

#ifdef SOCK_CLOEXEC

    fd = socket(af, type | SOCK_CLOEXEC, proto);

    if (fd == -1 && errno == EINVAL)

#endif

    {

        fd = socket(af, type, proto);

#if HAVE_FCNTL

        if (fd != -1) {

            if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)

                av_log(logctx, AV_LOG_DEBUG, "Failed to set close on exec\n");

        }

#endif

    }

#ifdef SO_NOSIGPIPE

    if (fd != -1) {

        if (setsockopt(fd, SOL_SOCKET, SO_NOSIGPIPE, &(int){1}, sizeof(int))) {

             av_log(logctx, AV_LOG_WARNING, "setsockopt(SO_NOSIGPIPE) failed\n");

        }

    }

#endif

    return fd;

}

int ff_listen(int fd, const struct sockaddr *addr,

              socklen_t addrlen, void *logctx)

{

    int ret;

    int reuse = 1;

    if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse))) {

        av_log(logctx, AV_LOG_WARNING, "setsockopt(SO_REUSEADDR) failed\n");

    }

    ret = bind(fd, addr, addrlen);

    if (ret)

        return ff_neterrno();

    ret = listen(fd, 1);

    if (ret)

        return ff_neterrno();

    return ret;

}

int ff_accept(int fd, int timeout, URLContext *h)

{

    int ret;

    struct pollfd lp = { fd, POLLIN, 0 };

    ret = ff_poll_interrupt(&lp, 1, timeout, &h->interrupt_callback);

    if (ret < 0)

        return ret;

    ret = accept(fd, NULL, NULL);

    if (ret < 0)

        return ff_neterrno();

    if (ff_socket_nonblock(ret, 1) < 0)

        av_log(h, AV_LOG_DEBUG, "ff_socket_nonblock failed\n");

    return ret;

}

int ff_listen_bind(int fd, const struct sockaddr *addr,

                   socklen_t addrlen, int timeout, URLContext *h)

{

    int ret;

    if ((ret = ff_listen(fd, addr, addrlen, h)) < 0)

        return ret;

    if ((ret = ff_accept(fd, timeout, h)) < 0)

        return ret;

    closesocket(fd);

    return ret;

}

int ff_listen_connect(int fd, const struct sockaddr *addr,

                      socklen_t addrlen, int timeout, URLContext *h,

                      int will_try_next)

{

    struct pollfd p = {fd, POLLOUT, 0};

    int ret;

    socklen_t optlen;

    if (ff_socket_nonblock(fd, 1) < 0)

        av_log(h, AV_LOG_DEBUG, "ff_socket_nonblock failed\n");

    while ((ret = connect(fd, addr, addrlen))) {

        ret = ff_neterrno();

        switch (ret) {

        case AVERROR(EINTR):

            if (ff_check_interrupt(&h->interrupt_callback))

                return AVERROR_EXIT;

            continue;

        case AVERROR(EINPROGRESS):

        case AVERROR(EAGAIN):

            ret = ff_poll_interrupt(&p, 1, timeout, &h->interrupt_callback);

            if (ret < 0)

                return ret;

            optlen = sizeof(ret);

            if (getsockopt (fd, SOL_SOCKET, SO_ERROR, &ret, &optlen))

                ret = AVUNERROR(ff_neterrno());

            if (ret != 0) {

                ret = AVERROR(ret);

                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));

            }

            av_fallthrough;

        default:

            return ret;

        }

    }

    return ret;

}

static void interleave_addrinfo(struct addrinfo *base)

{

    struct addrinfo **next = &base->ai_next;

    while (*next) {

        struct addrinfo *cur = *next;

        // Iterate forward until we find an entry of a different family.

        if (cur->ai_family == base->ai_family) {

            next = &cur->ai_next;

            continue;

        }

        if (cur == base->ai_next) {

            // If the first one following base is of a different family, just

            // move base forward one step and continue.

            base = cur;

            next = &base->ai_next;

            continue;

        }

        // Unchain cur from the rest of the list from its current spot.

        *next = cur->ai_next;

        // Hook in cur directly after base.

        cur->ai_next = base->ai_next;

        base->ai_next = cur;

        // Restart with a new base. We know that before moving the cur element,

        // everything between the previous base and cur had the same family,

        // different from cur->ai_family. Therefore, we can keep next pointing

        // where it was, and continue from there with base at the one after

        // cur.

        base = cur->ai_next;

    }

}

static void print_address_list(void *ctx, const struct addrinfo *addr,

                               const char *title)

{

    char hostbuf[100], portbuf[20];

    av_log(ctx, AV_LOG_DEBUG, "%s:\n", title);

    while (addr) {

        getnameinfo(addr->ai_addr, addr->ai_addrlen,

                    hostbuf, sizeof(hostbuf), portbuf, sizeof(portbuf),

                    NI_NUMERICHOST | NI_NUMERICSERV);

        av_log(ctx, AV_LOG_DEBUG, "Address %s port %s\n", hostbuf, portbuf);

        addr = addr->ai_next;

    }

}

struct ConnectionAttempt {

    int fd;

    int64_t deadline_us;

    struct addrinfo *addr;

};

// Returns < 0 on error, 0 on successfully started connection attempt,

// > 0 for a connection that succeeded already.

static int start_connect_attempt(struct ConnectionAttempt *attempt,

                                 struct addrinfo **ptr, int timeout_ms,

                                 URLContext *h,

                                 int (*customize_fd)(void *, int, int), void *customize_ctx)

{

    struct addrinfo *ai = *ptr;

    int ret;

    *ptr = ai->ai_next;

    attempt->fd = ff_socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol, h);

    if (attempt->fd < 0)

        return ff_neterrno();

    attempt->deadline_us = av_gettime_relative() + timeout_ms * 1000;

    attempt->addr = ai;

    ff_socket_nonblock(attempt->fd, 1);

    if (customize_fd) {

        ret = customize_fd(customize_ctx, attempt->fd, ai->ai_family);

        if (ret) {

            closesocket(attempt->fd);

            attempt->fd = -1;

            return ret;

        }

    }

    while ((ret = connect(attempt->fd, ai->ai_addr, ai->ai_addrlen))) {

        ret = ff_neterrno();

        switch (ret) {

        case AVERROR(EINTR):

            if (ff_check_interrupt(&h->interrupt_callback)) {

                closesocket(attempt->fd);

                attempt->fd = -1;

                return AVERROR_EXIT;

            }

            continue;

        case AVERROR(EINPROGRESS):

        case AVERROR(EAGAIN):

            return 0;

        default:

            closesocket(attempt->fd);

            attempt->fd = -1;

            return ret;

        }

    }

    return 1;

}

// Try a new connection to another address after 200 ms, as suggested in

// RFC 8305 (or sooner if an earlier attempt fails).

#define NEXT_ATTEMPT_DELAY_MS 200

int ff_connect_parallel(struct addrinfo *addrs, int timeout_ms_per_address,

                        int parallel, URLContext *h, int *fd,

                        int (*customize_fd)(void *, int, int), void *customize_ctx)

{

    struct ConnectionAttempt attempts[3];

    struct pollfd pfd[3];

    int nb_attempts = 0, i, j;

    int64_t next_attempt_us = av_gettime_relative(), next_deadline_us;

    int last_err = AVERROR(EIO);

    socklen_t optlen;

    char hostbuf[100], portbuf[20];

    if (parallel > FF_ARRAY_ELEMS(attempts))

        parallel = FF_ARRAY_ELEMS(attempts);

    print_address_list(h, addrs, "Original list of addresses");

    // This mutates the list, but the head of the list is still the same

    // element, so the caller, who owns the list, doesn't need to get

    // an updated pointer.

    interleave_addrinfo(addrs);

    print_address_list(h, addrs, "Interleaved list of addresses");

    while (nb_attempts > 0 || addrs) {

        // Start a new connection attempt, if possible.

        if (nb_attempts < parallel && addrs) {

            getnameinfo(addrs->ai_addr, addrs->ai_addrlen,

                        hostbuf, sizeof(hostbuf), portbuf, sizeof(portbuf),

                        NI_NUMERICHOST | NI_NUMERICSERV);

            av_log(h, AV_LOG_VERBOSE, "Starting connection attempt to %s port %s\n",

                                      hostbuf, portbuf);

            last_err = start_connect_attempt(&attempts[nb_attempts], &addrs,

                                             timeout_ms_per_address, h,

                                             customize_fd, customize_ctx);

            if (last_err < 0) {

                av_log(h, AV_LOG_VERBOSE, "Connected attempt failed: %s\n",

                                          av_err2str(last_err));

                continue;

            }

            if (last_err > 0) {

                for (i = 0; i < nb_attempts; i++)

                    closesocket(attempts[i].fd);

                *fd = attempts[nb_attempts].fd;

                return 0;

            }

            pfd[nb_attempts].fd = attempts[nb_attempts].fd;

            pfd[nb_attempts].events = POLLOUT;

            next_attempt_us = av_gettime_relative() + NEXT_ATTEMPT_DELAY_MS * 1000;

            nb_attempts++;

        }

        av_assert0(nb_attempts > 0);

        // The connection attempts are sorted from oldest to newest, so the

        // first one will have the earliest deadline.

        next_deadline_us = attempts[0].deadline_us;

        // If we can start another attempt in parallel, wait until that time.

        if (nb_attempts < parallel && addrs)

            next_deadline_us = FFMIN(next_deadline_us, next_attempt_us);

        last_err = ff_poll_interrupt(pfd, nb_attempts,

                                     (next_deadline_us - av_gettime_relative())/1000,

                                     &h->interrupt_callback);

        if (last_err < 0 && last_err != AVERROR(ETIMEDOUT))

            break;

        // Check the status from the poll output.

        for (i = 0; i < nb_attempts; i++) {

            last_err = 0;

            if (pfd[i].revents) {

                // Some sort of action for this socket, check its status (either

                // a successful connection or an error).

                optlen = sizeof(last_err);

                if (getsockopt(attempts[i].fd, SOL_SOCKET, SO_ERROR, &last_err, &optlen))

                    last_err = ff_neterrno();

                else if (last_err != 0)

                    last_err = AVERROR(last_err);

                if (last_err == 0) {

                    // Everything is ok, we seem to have a successful

                    // connection. Close other sockets and return this one.

                    for (j = 0; j < nb_attempts; j++)

                        if (j != i)

                            closesocket(attempts[j].fd);

                    *fd = attempts[i].fd;

                    getnameinfo(attempts[i].addr->ai_addr, attempts[i].addr->ai_addrlen,

                                hostbuf, sizeof(hostbuf), portbuf, sizeof(portbuf),

                                NI_NUMERICHOST | NI_NUMERICSERV);

                    av_log(h, AV_LOG_VERBOSE, "Successfully connected to %s port %s\n",

                                              hostbuf, portbuf);

                    return 0;

                }

            }

            if (attempts[i].deadline_us < av_gettime_relative() && !last_err)

                last_err = AVERROR(ETIMEDOUT);

            if (!last_err)

                continue;

            // Error (or timeout) for this socket; close the socket and remove

            // it from the attempts/pfd arrays, to let a new attempt start

            // directly.

            getnameinfo(attempts[i].addr->ai_addr, attempts[i].addr->ai_addrlen,

                        hostbuf, sizeof(hostbuf), portbuf, sizeof(portbuf),

                        NI_NUMERICHOST | NI_NUMERICSERV);

            av_log(h, AV_LOG_VERBOSE, "Connection attempt to %s port %s "

                                      "failed: %s\n", hostbuf, portbuf, av_err2str(last_err));

            closesocket(attempts[i].fd);

            memmove(&attempts[i], &attempts[i + 1],

                    (nb_attempts - i - 1) * sizeof(*attempts));

            memmove(&pfd[i], &pfd[i + 1],

                    (nb_attempts - i - 1) * sizeof(*pfd));

            i--;

            nb_attempts--;

        }

    }

    for (i = 0; i < nb_attempts; i++)

        closesocket(attempts[i].fd);

    if (last_err >= 0)

        last_err = AVERROR(ECONNREFUSED);

    if (last_err != AVERROR_EXIT) {

        av_log(h, AV_LOG_ERROR, "Connection to %s failed: %s\n",

               h->filename, av_err2str(last_err));

    }

    return last_err;

}

static int match_host_pattern(const char *pattern, const char *hostname)

{

    int len_p, len_h;

    if (!strcmp(pattern, "*"))

        return 1;

    // Skip a possible *. at the start of the pattern

    if (pattern[0] == '*')

        pattern++;

    if (pattern[0] == '.')

        pattern++;

    len_p = strlen(pattern);

    len_h = strlen(hostname);

    if (len_p > len_h)

        return 0;

    // Simply check if the end of hostname is equal to 'pattern'

    if (!strcmp(pattern, &hostname[len_h - len_p])) {

        if (len_h == len_p)

            return 1; // Exact match

        if (hostname[len_h - len_p - 1] == '.')

            return 1; // The matched substring is a domain and not just a substring of a domain

    }

    return 0;

}

int ff_http_match_no_proxy(const char *no_proxy, const char *hostname)

{

    char *buf, *start;

    int ret = 0;

    if (!no_proxy)

        return 0;

    if (!hostname)

        return 0;

    buf = av_strdup(no_proxy);

    if (!buf)

        return 0;

    start = buf;

    while (start) {

        char *sep, *next = NULL;

        start += strspn(start, " ,");

        sep = start + strcspn(start, " ,");

        if (*sep) {

            next = sep + 1;

            *sep = '\0';

        }

        if (match_host_pattern(start, hostname)) {

            ret = 1;

            break;

        }

        start = next;

    }

    av_free(buf);

    return ret;

}

void ff_log_net_error(void *ctx, int level, const char* prefix)

{

    av_log(ctx, level, "%s: %s\n", prefix, av_err2str(ff_neterrno()));

}