Mercurial > hg > nginx

view src/core/ngx_connection.c @ 7064:ecb5cd305b06

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Core: disabled SO_REUSEPORT when testing config (ticket #1300). When closing a socket with SO_REUSEPORT, Linux drops all connections waiting in this socket's listen queue. Previously, it was believed to only result in connection resets when reconfiguring nginx to use smaller number of worker processes. It also results in connection resets during configuration testing though. Workaround is to avoid using SO_REUSEPORT when testing configuration. It should prevent listening sockets from being created if a conflicting socket already exists, while still preserving detection of other possible errors. It should also cover UDP sockets. The only downside of this approach seems to be that a configuration testing won't be able to properly report the case when nginx was compiled with SO_REUSEPORT, but the kernel is not able to set it. Such errors will be reported on a real start instead.
author Maxim Dounin <mdounin@mdounin.ru>
date Tue, 11 Jul 2017 19:59:56 +0300
parents ed1101bbf19f
children c0d89f602d08
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>


ngx_os_io_t  ngx_io;


static void ngx_drain_connections(ngx_cycle_t *cycle);


ngx_listening_t *
ngx_create_listening(ngx_conf_t *cf, struct sockaddr *sockaddr,
    socklen_t socklen)
{
    size_t            len;
    ngx_listening_t  *ls;
    struct sockaddr  *sa;
    u_char            text[NGX_SOCKADDR_STRLEN];

    ls = ngx_array_push(&cf->cycle->listening);
    if (ls == NULL) {
        return NULL;
    }

    ngx_memzero(ls, sizeof(ngx_listening_t));

    sa = ngx_palloc(cf->pool, socklen);
    if (sa == NULL) {
        return NULL;
    }

    ngx_memcpy(sa, sockaddr, socklen);

    ls->sockaddr = sa;
    ls->socklen = socklen;

    len = ngx_sock_ntop(sa, socklen, text, NGX_SOCKADDR_STRLEN, 1);
    ls->addr_text.len = len;

    switch (ls->sockaddr->sa_family) {
#if (NGX_HAVE_INET6)
    case AF_INET6:
        ls->addr_text_max_len = NGX_INET6_ADDRSTRLEN;
        break;
#endif
#if (NGX_HAVE_UNIX_DOMAIN)
    case AF_UNIX:
        ls->addr_text_max_len = NGX_UNIX_ADDRSTRLEN;
        len++;
        break;
#endif
    case AF_INET:
        ls->addr_text_max_len = NGX_INET_ADDRSTRLEN;
        break;
    default:
        ls->addr_text_max_len = NGX_SOCKADDR_STRLEN;
        break;
    }

    ls->addr_text.data = ngx_pnalloc(cf->pool, len);
    if (ls->addr_text.data == NULL) {
        return NULL;
    }

    ngx_memcpy(ls->addr_text.data, text, len);

    ls->fd = (ngx_socket_t) -1;
    ls->type = SOCK_STREAM;

    ls->backlog = NGX_LISTEN_BACKLOG;
    ls->rcvbuf = -1;
    ls->sndbuf = -1;

#if (NGX_HAVE_SETFIB)
    ls->setfib = -1;
#endif

#if (NGX_HAVE_TCP_FASTOPEN)
    ls->fastopen = -1;
#endif

    return ls;
}


ngx_int_t
ngx_clone_listening(ngx_conf_t *cf, ngx_listening_t *ls)
{
#if (NGX_HAVE_REUSEPORT)

    ngx_int_t         n;
    ngx_core_conf_t  *ccf;
    ngx_listening_t   ols;

    if (!ls->reuseport) {
        return NGX_OK;
    }

    ols = *ls;

    ccf = (ngx_core_conf_t *) ngx_get_conf(cf->cycle->conf_ctx,
                                           ngx_core_module);

    for (n = 1; n < ccf->worker_processes; n++) {

        /* create a socket for each worker process */

        ls = ngx_array_push(&cf->cycle->listening);
        if (ls == NULL) {
            return NGX_ERROR;
        }

        *ls = ols;
        ls->worker = n;
    }

#endif

    return NGX_OK;
}


ngx_int_t
ngx_set_inherited_sockets(ngx_cycle_t *cycle)
{
    size_t                     len;
    ngx_uint_t                 i;
    ngx_listening_t           *ls;
    socklen_t                  olen;
#if (NGX_HAVE_DEFERRED_ACCEPT || NGX_HAVE_TCP_FASTOPEN)
    ngx_err_t                  err;
#endif
#if (NGX_HAVE_DEFERRED_ACCEPT && defined SO_ACCEPTFILTER)
    struct accept_filter_arg   af;
#endif
#if (NGX_HAVE_DEFERRED_ACCEPT && defined TCP_DEFER_ACCEPT)
    int                        timeout;
#endif
#if (NGX_HAVE_REUSEPORT)
    int                        reuseport;
#endif

    ls = cycle->listening.elts;
    for (i = 0; i < cycle->listening.nelts; i++) {

        ls[i].sockaddr = ngx_palloc(cycle->pool, sizeof(ngx_sockaddr_t));
        if (ls[i].sockaddr == NULL) {
            return NGX_ERROR;
        }

        ls[i].socklen = sizeof(ngx_sockaddr_t);
        if (getsockname(ls[i].fd, ls[i].sockaddr, &ls[i].socklen) == -1) {
            ngx_log_error(NGX_LOG_CRIT, cycle->log, ngx_socket_errno,
                          "getsockname() of the inherited "
                          "socket #%d failed", ls[i].fd);
            ls[i].ignore = 1;
            continue;
        }

        switch (ls[i].sockaddr->sa_family) {

#if (NGX_HAVE_INET6)
        case AF_INET6:
            ls[i].addr_text_max_len = NGX_INET6_ADDRSTRLEN;
            len = NGX_INET6_ADDRSTRLEN + sizeof("[]:65535") - 1;
            break;
#endif

#if (NGX_HAVE_UNIX_DOMAIN)
        case AF_UNIX:
            ls[i].addr_text_max_len = NGX_UNIX_ADDRSTRLEN;
            len = NGX_UNIX_ADDRSTRLEN;
            break;
#endif

        case AF_INET:
            ls[i].addr_text_max_len = NGX_INET_ADDRSTRLEN;
            len = NGX_INET_ADDRSTRLEN + sizeof(":65535") - 1;
            break;

        default:
            ngx_log_error(NGX_LOG_CRIT, cycle->log, ngx_socket_errno,
                          "the inherited socket #%d has "
                          "an unsupported protocol family", ls[i].fd);
            ls[i].ignore = 1;
            continue;
        }

        ls[i].addr_text.data = ngx_pnalloc(cycle->pool, len);
        if (ls[i].addr_text.data == NULL) {
            return NGX_ERROR;
        }

        len = ngx_sock_ntop(ls[i].sockaddr, ls[i].socklen,
                            ls[i].addr_text.data, len, 1);
        if (len == 0) {
            return NGX_ERROR;
        }

        ls[i].addr_text.len = len;

        ls[i].backlog = NGX_LISTEN_BACKLOG;

        olen = sizeof(int);

        if (getsockopt(ls[i].fd, SOL_SOCKET, SO_TYPE, (void *) &ls[i].type,
                       &olen)
            == -1)
        {
            ngx_log_error(NGX_LOG_CRIT, cycle->log, ngx_socket_errno,
                          "getsockopt(SO_TYPE) %V failed", &ls[i].addr_text);
            ls[i].ignore = 1;
            continue;
        }

        olen = sizeof(int);

        if (getsockopt(ls[i].fd, SOL_SOCKET, SO_RCVBUF, (void *) &ls[i].rcvbuf,
                       &olen)
            == -1)
        {
            ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
                          "getsockopt(SO_RCVBUF) %V failed, ignored",
                          &ls[i].addr_text);

            ls[i].rcvbuf = -1;
        }

        olen = sizeof(int);

        if (getsockopt(ls[i].fd, SOL_SOCKET, SO_SNDBUF, (void *) &ls[i].sndbuf,
                       &olen)
            == -1)
        {
            ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
                          "getsockopt(SO_SNDBUF) %V failed, ignored",
                          &ls[i].addr_text);

            ls[i].sndbuf = -1;
        }

#if 0
        /* SO_SETFIB is currently a set only option */

#if (NGX_HAVE_SETFIB)

        olen = sizeof(int);

        if (getsockopt(ls[i].fd, SOL_SOCKET, SO_SETFIB,
                       (void *) &ls[i].setfib, &olen)
            == -1)
        {
            ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
                          "getsockopt(SO_SETFIB) %V failed, ignored",
                          &ls[i].addr_text);

            ls[i].setfib = -1;
        }

#endif
#endif

#if (NGX_HAVE_REUSEPORT)

        reuseport = 0;
        olen = sizeof(int);

        if (getsockopt(ls[i].fd, SOL_SOCKET, SO_REUSEPORT,
                       (void *) &reuseport, &olen)
            == -1)
        {
            ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
                          "getsockopt(SO_REUSEPORT) %V failed, ignored",
                          &ls[i].addr_text);

        } else {
            ls[i].reuseport = reuseport ? 1 : 0;
        }

#endif

        if (ls[i].type != SOCK_STREAM) {
            continue;
        }

#if (NGX_HAVE_TCP_FASTOPEN)

        olen = sizeof(int);

        if (getsockopt(ls[i].fd, IPPROTO_TCP, TCP_FASTOPEN,
                       (void *) &ls[i].fastopen, &olen)
            == -1)
        {
            err = ngx_socket_errno;

            if (err != NGX_EOPNOTSUPP && err != NGX_ENOPROTOOPT) {
                ngx_log_error(NGX_LOG_NOTICE, cycle->log, err,
                              "getsockopt(TCP_FASTOPEN) %V failed, ignored",
                              &ls[i].addr_text);
            }

            ls[i].fastopen = -1;
        }

#endif

#if (NGX_HAVE_DEFERRED_ACCEPT && defined SO_ACCEPTFILTER)

        ngx_memzero(&af, sizeof(struct accept_filter_arg));
        olen = sizeof(struct accept_filter_arg);

        if (getsockopt(ls[i].fd, SOL_SOCKET, SO_ACCEPTFILTER, &af, &olen)
            == -1)
        {
            err = ngx_socket_errno;

            if (err == NGX_EINVAL) {
                continue;
            }

            ngx_log_error(NGX_LOG_NOTICE, cycle->log, err,
                          "getsockopt(SO_ACCEPTFILTER) for %V failed, ignored",
                          &ls[i].addr_text);
            continue;
        }

        if (olen < sizeof(struct accept_filter_arg) || af.af_name[0] == '\0') {
            continue;
        }

        ls[i].accept_filter = ngx_palloc(cycle->pool, 16);
        if (ls[i].accept_filter == NULL) {
            return NGX_ERROR;
        }

        (void) ngx_cpystrn((u_char *) ls[i].accept_filter,
                           (u_char *) af.af_name, 16);
#endif

#if (NGX_HAVE_DEFERRED_ACCEPT && defined TCP_DEFER_ACCEPT)

        timeout = 0;
        olen = sizeof(int);

        if (getsockopt(ls[i].fd, IPPROTO_TCP, TCP_DEFER_ACCEPT, &timeout, &olen)
            == -1)
        {
            err = ngx_socket_errno;

            if (err == NGX_EOPNOTSUPP) {
                continue;
            }

            ngx_log_error(NGX_LOG_NOTICE, cycle->log, err,
                          "getsockopt(TCP_DEFER_ACCEPT) for %V failed, ignored",
                          &ls[i].addr_text);
            continue;
        }

        if (olen < sizeof(int) || timeout == 0) {
            continue;
        }

        ls[i].deferred_accept = 1;
#endif
    }

    return NGX_OK;
}


ngx_int_t
ngx_open_listening_sockets(ngx_cycle_t *cycle)
{
    int               reuseaddr;
    ngx_uint_t        i, tries, failed;
    ngx_err_t         err;
    ngx_log_t        *log;
    ngx_socket_t      s;
    ngx_listening_t  *ls;

    reuseaddr = 1;
#if (NGX_SUPPRESS_WARN)
    failed = 0;
#endif

    log = cycle->log;

    /* TODO: configurable try number */

    for (tries = 5; tries; tries--) {
        failed = 0;

        /* for each listening socket */

        ls = cycle->listening.elts;
        for (i = 0; i < cycle->listening.nelts; i++) {

            if (ls[i].ignore) {
                continue;
            }

#if (NGX_HAVE_REUSEPORT)

            if (ls[i].add_reuseport) {

                /*
                 * to allow transition from a socket without SO_REUSEPORT
                 * to multiple sockets with SO_REUSEPORT, we have to set
                 * SO_REUSEPORT on the old socket before opening new ones
                 */

                int  reuseport = 1;

                if (setsockopt(ls[i].fd, SOL_SOCKET, SO_REUSEPORT,
                               (const void *) &reuseport, sizeof(int))
                    == -1)
                {
                    ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
                                  "setsockopt(SO_REUSEPORT) %V failed, ignored",
                                  &ls[i].addr_text);
                }

                ls[i].add_reuseport = 0;
            }
#endif

            if (ls[i].fd != (ngx_socket_t) -1) {
                continue;
            }

            if (ls[i].inherited) {

                /* TODO: close on exit */
                /* TODO: nonblocking */
                /* TODO: deferred accept */

                continue;
            }

            s = ngx_socket(ls[i].sockaddr->sa_family, ls[i].type, 0);

            if (s == (ngx_socket_t) -1) {
                ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
                              ngx_socket_n " %V failed", &ls[i].addr_text);
                return NGX_ERROR;
            }

            if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
                           (const void *) &reuseaddr, sizeof(int))
                == -1)
            {
                ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
                              "setsockopt(SO_REUSEADDR) %V failed",
                              &ls[i].addr_text);

                if (ngx_close_socket(s) == -1) {
                    ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
                                  ngx_close_socket_n " %V failed",
                                  &ls[i].addr_text);
                }

                return NGX_ERROR;
            }

#if (NGX_HAVE_REUSEPORT)

            if (ls[i].reuseport && !ngx_test_config) {
                int  reuseport;

                reuseport = 1;

                if (setsockopt(s, SOL_SOCKET, SO_REUSEPORT,
                               (const void *) &reuseport, sizeof(int))
                    == -1)
                {
                    ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
                                  "setsockopt(SO_REUSEPORT) %V failed, ignored",
                                  &ls[i].addr_text);

                    if (ngx_close_socket(s) == -1) {
                        ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
                                      ngx_close_socket_n " %V failed",
                                      &ls[i].addr_text);
                    }

                    return NGX_ERROR;
                }
            }
#endif

#if (NGX_HAVE_INET6 && defined IPV6_V6ONLY)

            if (ls[i].sockaddr->sa_family == AF_INET6) {
                int  ipv6only;

                ipv6only = ls[i].ipv6only;

                if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY,
                               (const void *) &ipv6only, sizeof(int))
                    == -1)
                {
                    ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
                                  "setsockopt(IPV6_V6ONLY) %V failed, ignored",
                                  &ls[i].addr_text);
                }
            }
#endif
            /* TODO: close on exit */

            if (!(ngx_event_flags & NGX_USE_IOCP_EVENT)) {
                if (ngx_nonblocking(s) == -1) {
                    ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
                                  ngx_nonblocking_n " %V failed",
                                  &ls[i].addr_text);

                    if (ngx_close_socket(s) == -1) {
                        ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
                                      ngx_close_socket_n " %V failed",
                                      &ls[i].addr_text);
                    }

                    return NGX_ERROR;
                }
            }

            ngx_log_debug2(NGX_LOG_DEBUG_CORE, log, 0,
                           "bind() %V #%d ", &ls[i].addr_text, s);

            if (bind(s, ls[i].sockaddr, ls[i].socklen) == -1) {
                err = ngx_socket_errno;

                if (err != NGX_EADDRINUSE || !ngx_test_config) {
                    ngx_log_error(NGX_LOG_EMERG, log, err,
                                  "bind() to %V failed", &ls[i].addr_text);
                }

                if (ngx_close_socket(s) == -1) {
                    ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
                                  ngx_close_socket_n " %V failed",
                                  &ls[i].addr_text);
                }

                if (err != NGX_EADDRINUSE) {
                    return NGX_ERROR;
                }

                if (!ngx_test_config) {
                    failed = 1;
                }

                continue;
            }

#if (NGX_HAVE_UNIX_DOMAIN)

            if (ls[i].sockaddr->sa_family == AF_UNIX) {
                mode_t   mode;
                u_char  *name;

                name = ls[i].addr_text.data + sizeof("unix:") - 1;
                mode = (S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH);

                if (chmod((char *) name, mode) == -1) {
                    ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
                                  "chmod() \"%s\" failed", name);
                }

                if (ngx_test_config) {
                    if (ngx_delete_file(name) == NGX_FILE_ERROR) {
                        ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
                                      ngx_delete_file_n " %s failed", name);
                    }
                }
            }
#endif

            if (ls[i].type != SOCK_STREAM) {
                ls[i].fd = s;
                continue;
            }

            if (listen(s, ls[i].backlog) == -1) {
                err = ngx_socket_errno;

                /*
                 * on OpenVZ after suspend/resume EADDRINUSE
                 * may be returned by listen() instead of bind(), see
                 * https://bugzilla.openvz.org/show_bug.cgi?id=2470
                 */

                if (err != NGX_EADDRINUSE || !ngx_test_config) {
                    ngx_log_error(NGX_LOG_EMERG, log, err,
                                  "listen() to %V, backlog %d failed",
                                  &ls[i].addr_text, ls[i].backlog);
                }

                if (ngx_close_socket(s) == -1) {
                    ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
                                  ngx_close_socket_n " %V failed",
                                  &ls[i].addr_text);
                }

                if (err != NGX_EADDRINUSE) {
                    return NGX_ERROR;
                }

                if (!ngx_test_config) {
                    failed = 1;
                }

                continue;
            }

            ls[i].listen = 1;

            ls[i].fd = s;
        }

        if (!failed) {
            break;
        }

        /* TODO: delay configurable */

        ngx_log_error(NGX_LOG_NOTICE, log, 0,
                      "try again to bind() after 500ms");

        ngx_msleep(500);
    }

    if (failed) {
        ngx_log_error(NGX_LOG_EMERG, log, 0, "still could not bind()");
        return NGX_ERROR;
    }

    return NGX_OK;
}


void
ngx_configure_listening_sockets(ngx_cycle_t *cycle)
{
    int                        value;
    ngx_uint_t                 i;
    ngx_listening_t           *ls;

#if (NGX_HAVE_DEFERRED_ACCEPT && defined SO_ACCEPTFILTER)
    struct accept_filter_arg   af;
#endif

    ls = cycle->listening.elts;
    for (i = 0; i < cycle->listening.nelts; i++) {

        ls[i].log = *ls[i].logp;

        if (ls[i].rcvbuf != -1) {
            if (setsockopt(ls[i].fd, SOL_SOCKET, SO_RCVBUF,
                           (const void *) &ls[i].rcvbuf, sizeof(int))
                == -1)
            {
                ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
                              "setsockopt(SO_RCVBUF, %d) %V failed, ignored",
                              ls[i].rcvbuf, &ls[i].addr_text);
            }
        }

        if (ls[i].sndbuf != -1) {
            if (setsockopt(ls[i].fd, SOL_SOCKET, SO_SNDBUF,
                           (const void *) &ls[i].sndbuf, sizeof(int))
                == -1)
            {
                ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
                              "setsockopt(SO_SNDBUF, %d) %V failed, ignored",
                              ls[i].sndbuf, &ls[i].addr_text);
            }
        }

        if (ls[i].keepalive) {
            value = (ls[i].keepalive == 1) ? 1 : 0;

            if (setsockopt(ls[i].fd, SOL_SOCKET, SO_KEEPALIVE,
                           (const void *) &value, sizeof(int))
                == -1)
            {
                ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
                              "setsockopt(SO_KEEPALIVE, %d) %V failed, ignored",
                              value, &ls[i].addr_text);
            }
        }

#if (NGX_HAVE_KEEPALIVE_TUNABLE)

        if (ls[i].keepidle) {
            value = ls[i].keepidle;

#if (NGX_KEEPALIVE_FACTOR)
            value *= NGX_KEEPALIVE_FACTOR;
#endif

            if (setsockopt(ls[i].fd, IPPROTO_TCP, TCP_KEEPIDLE,
                           (const void *) &value, sizeof(int))
                == -1)
            {
                ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
                              "setsockopt(TCP_KEEPIDLE, %d) %V failed, ignored",
                              value, &ls[i].addr_text);
            }
        }

        if (ls[i].keepintvl) {
            value = ls[i].keepintvl;

#if (NGX_KEEPALIVE_FACTOR)
            value *= NGX_KEEPALIVE_FACTOR;
#endif

            if (setsockopt(ls[i].fd, IPPROTO_TCP, TCP_KEEPINTVL,
                           (const void *) &value, sizeof(int))
                == -1)
            {
                ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
                             "setsockopt(TCP_KEEPINTVL, %d) %V failed, ignored",
                             value, &ls[i].addr_text);
            }
        }

        if (ls[i].keepcnt) {
            if (setsockopt(ls[i].fd, IPPROTO_TCP, TCP_KEEPCNT,
                           (const void *) &ls[i].keepcnt, sizeof(int))
                == -1)
            {
                ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
                              "setsockopt(TCP_KEEPCNT, %d) %V failed, ignored",
                              ls[i].keepcnt, &ls[i].addr_text);
            }
        }

#endif

#if (NGX_HAVE_SETFIB)
        if (ls[i].setfib != -1) {
            if (setsockopt(ls[i].fd, SOL_SOCKET, SO_SETFIB,
                           (const void *) &ls[i].setfib, sizeof(int))
                == -1)
            {
                ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
                              "setsockopt(SO_SETFIB, %d) %V failed, ignored",
                              ls[i].setfib, &ls[i].addr_text);
            }
        }
#endif

#if (NGX_HAVE_TCP_FASTOPEN)
        if (ls[i].fastopen != -1) {
            if (setsockopt(ls[i].fd, IPPROTO_TCP, TCP_FASTOPEN,
                           (const void *) &ls[i].fastopen, sizeof(int))
                == -1)
            {
                ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
                              "setsockopt(TCP_FASTOPEN, %d) %V failed, ignored",
                              ls[i].fastopen, &ls[i].addr_text);
            }
        }
#endif

#if 0
        if (1) {
            int tcp_nodelay = 1;

            if (setsockopt(ls[i].fd, IPPROTO_TCP, TCP_NODELAY,
                       (const void *) &tcp_nodelay, sizeof(int))
                == -1)
            {
                ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
                              "setsockopt(TCP_NODELAY) %V failed, ignored",
                              &ls[i].addr_text);
            }
        }
#endif

        if (ls[i].listen) {

            /* change backlog via listen() */

            if (listen(ls[i].fd, ls[i].backlog) == -1) {
                ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
                              "listen() to %V, backlog %d failed, ignored",
                              &ls[i].addr_text, ls[i].backlog);
            }
        }

        /*
         * setting deferred mode should be last operation on socket,
         * because code may prematurely continue cycle on failure
         */

#if (NGX_HAVE_DEFERRED_ACCEPT)

#ifdef SO_ACCEPTFILTER

        if (ls[i].delete_deferred) {
            if (setsockopt(ls[i].fd, SOL_SOCKET, SO_ACCEPTFILTER, NULL, 0)
                == -1)
            {
                ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
                              "setsockopt(SO_ACCEPTFILTER, NULL) "
                              "for %V failed, ignored",
                              &ls[i].addr_text);

                if (ls[i].accept_filter) {
                    ngx_log_error(NGX_LOG_ALERT, cycle->log, 0,
                                  "could not change the accept filter "
                                  "to \"%s\" for %V, ignored",
                                  ls[i].accept_filter, &ls[i].addr_text);
                }

                continue;
            }

            ls[i].deferred_accept = 0;
        }

        if (ls[i].add_deferred) {
            ngx_memzero(&af, sizeof(struct accept_filter_arg));
            (void) ngx_cpystrn((u_char *) af.af_name,
                               (u_char *) ls[i].accept_filter, 16);

            if (setsockopt(ls[i].fd, SOL_SOCKET, SO_ACCEPTFILTER,
                           &af, sizeof(struct accept_filter_arg))
                == -1)
            {
                ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
                              "setsockopt(SO_ACCEPTFILTER, \"%s\") "
                              "for %V failed, ignored",
                              ls[i].accept_filter, &ls[i].addr_text);
                continue;
            }

            ls[i].deferred_accept = 1;
        }

#endif

#ifdef TCP_DEFER_ACCEPT

        if (ls[i].add_deferred || ls[i].delete_deferred) {

            if (ls[i].add_deferred) {
                /*
                 * There is no way to find out how long a connection was
                 * in queue (and a connection may bypass deferred queue at all
                 * if syncookies were used), hence we use 1 second timeout
                 * here.
                 */
                value = 1;

            } else {
                value = 0;
            }

            if (setsockopt(ls[i].fd, IPPROTO_TCP, TCP_DEFER_ACCEPT,
                           &value, sizeof(int))
                == -1)
            {
                ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
                              "setsockopt(TCP_DEFER_ACCEPT, %d) for %V failed, "
                              "ignored",
                              value, &ls[i].addr_text);

                continue;
            }
        }

        if (ls[i].add_deferred) {
            ls[i].deferred_accept = 1;
        }

#endif

#endif /* NGX_HAVE_DEFERRED_ACCEPT */

#if (NGX_HAVE_IP_RECVDSTADDR)

        if (ls[i].wildcard
            && ls[i].type == SOCK_DGRAM
            && ls[i].sockaddr->sa_family == AF_INET)
        {
            value = 1;

            if (setsockopt(ls[i].fd, IPPROTO_IP, IP_RECVDSTADDR,
                           (const void *) &value, sizeof(int))
                == -1)
            {
                ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
                              "setsockopt(IP_RECVDSTADDR) "
                              "for %V failed, ignored",
                              &ls[i].addr_text);
            }
        }

#elif (NGX_HAVE_IP_PKTINFO)

        if (ls[i].wildcard
            && ls[i].type == SOCK_DGRAM
            && ls[i].sockaddr->sa_family == AF_INET)
        {
            value = 1;

            if (setsockopt(ls[i].fd, IPPROTO_IP, IP_PKTINFO,
                           (const void *) &value, sizeof(int))
                == -1)
            {
                ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
                              "setsockopt(IP_PKTINFO) "
                              "for %V failed, ignored",
                              &ls[i].addr_text);
            }
        }

#endif

#if (NGX_HAVE_INET6 && NGX_HAVE_IPV6_RECVPKTINFO)

        if (ls[i].wildcard
            && ls[i].type == SOCK_DGRAM
            && ls[i].sockaddr->sa_family == AF_INET6)
        {
            value = 1;

            if (setsockopt(ls[i].fd, IPPROTO_IPV6, IPV6_RECVPKTINFO,
                           (const void *) &value, sizeof(int))
                == -1)
            {
                ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
                              "setsockopt(IPV6_RECVPKTINFO) "
                              "for %V failed, ignored",
                              &ls[i].addr_text);
            }
        }

#endif
    }

    return;
}


void
ngx_close_listening_sockets(ngx_cycle_t *cycle)
{
    ngx_uint_t         i;
    ngx_listening_t   *ls;
    ngx_connection_t  *c;

    if (ngx_event_flags & NGX_USE_IOCP_EVENT) {
        return;
    }

    ngx_accept_mutex_held = 0;
    ngx_use_accept_mutex = 0;

    ls = cycle->listening.elts;
    for (i = 0; i < cycle->listening.nelts; i++) {

        c = ls[i].connection;

        if (c) {
            if (c->read->active) {
                if (ngx_event_flags & NGX_USE_EPOLL_EVENT) {

                    /*
                     * it seems that Linux-2.6.x OpenVZ sends events
                     * for closed shared listening sockets unless
                     * the events was explicitly deleted
                     */

                    ngx_del_event(c->read, NGX_READ_EVENT, 0);

                } else {
                    ngx_del_event(c->read, NGX_READ_EVENT, NGX_CLOSE_EVENT);
                }
            }

            ngx_free_connection(c);

            c->fd = (ngx_socket_t) -1;
        }

        ngx_log_debug2(NGX_LOG_DEBUG_CORE, cycle->log, 0,
                       "close listening %V #%d ", &ls[i].addr_text, ls[i].fd);

        if (ngx_close_socket(ls[i].fd) == -1) {
            ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_socket_errno,
                          ngx_close_socket_n " %V failed", &ls[i].addr_text);
        }

#if (NGX_HAVE_UNIX_DOMAIN)

        if (ls[i].sockaddr->sa_family == AF_UNIX
            && ngx_process <= NGX_PROCESS_MASTER
            && ngx_new_binary == 0)
        {
            u_char *name = ls[i].addr_text.data + sizeof("unix:") - 1;

            if (ngx_delete_file(name) == NGX_FILE_ERROR) {
                ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_socket_errno,
                              ngx_delete_file_n " %s failed", name);
            }
        }

#endif

        ls[i].fd = (ngx_socket_t) -1;
    }

    cycle->listening.nelts = 0;
}


ngx_connection_t *
ngx_get_connection(ngx_socket_t s, ngx_log_t *log)
{
    ngx_uint_t         instance;
    ngx_event_t       *rev, *wev;
    ngx_connection_t  *c;

    /* disable warning: Win32 SOCKET is u_int while UNIX socket is int */

    if (ngx_cycle->files && (ngx_uint_t) s >= ngx_cycle->files_n) {
        ngx_log_error(NGX_LOG_ALERT, log, 0,
                      "the new socket has number %d, "
                      "but only %ui files are available",
                      s, ngx_cycle->files_n);
        return NULL;
    }

    c = ngx_cycle->free_connections;

    if (c == NULL) {
        ngx_drain_connections((ngx_cycle_t *) ngx_cycle);
        c = ngx_cycle->free_connections;
    }

    if (c == NULL) {
        ngx_log_error(NGX_LOG_ALERT, log, 0,
                      "%ui worker_connections are not enough",
                      ngx_cycle->connection_n);

        return NULL;
    }

    ngx_cycle->free_connections = c->data;
    ngx_cycle->free_connection_n--;

    if (ngx_cycle->files && ngx_cycle->files[s] == NULL) {
        ngx_cycle->files[s] = c;
    }

    rev = c->read;
    wev = c->write;

    ngx_memzero(c, sizeof(ngx_connection_t));

    c->read = rev;
    c->write = wev;
    c->fd = s;
    c->log = log;

    instance = rev->instance;

    ngx_memzero(rev, sizeof(ngx_event_t));
    ngx_memzero(wev, sizeof(ngx_event_t));

    rev->instance = !instance;
    wev->instance = !instance;

    rev->index = NGX_INVALID_INDEX;
    wev->index = NGX_INVALID_INDEX;

    rev->data = c;
    wev->data = c;

    wev->write = 1;

    return c;
}


void
ngx_free_connection(ngx_connection_t *c)
{
    c->data = ngx_cycle->free_connections;
    ngx_cycle->free_connections = c;
    ngx_cycle->free_connection_n++;

    if (ngx_cycle->files && ngx_cycle->files[c->fd] == c) {
        ngx_cycle->files[c->fd] = NULL;
    }
}


void
ngx_close_connection(ngx_connection_t *c)
{
    ngx_err_t     err;
    ngx_uint_t    log_error, level;
    ngx_socket_t  fd;

    if (c->fd == (ngx_socket_t) -1) {
        ngx_log_error(NGX_LOG_ALERT, c->log, 0, "connection already closed");
        return;
    }

    if (c->read->timer_set) {
        ngx_del_timer(c->read);
    }

    if (c->write->timer_set) {
        ngx_del_timer(c->write);
    }

    if (!c->shared) {
        if (ngx_del_conn) {
            ngx_del_conn(c, NGX_CLOSE_EVENT);

        } else {
            if (c->read->active || c->read->disabled) {
                ngx_del_event(c->read, NGX_READ_EVENT, NGX_CLOSE_EVENT);
            }

            if (c->write->active || c->write->disabled) {
                ngx_del_event(c->write, NGX_WRITE_EVENT, NGX_CLOSE_EVENT);
            }
        }
    }

    if (c->read->posted) {
        ngx_delete_posted_event(c->read);
    }

    if (c->write->posted) {
        ngx_delete_posted_event(c->write);
    }

    c->read->closed = 1;
    c->write->closed = 1;

    ngx_reusable_connection(c, 0);

    log_error = c->log_error;

    ngx_free_connection(c);

    fd = c->fd;
    c->fd = (ngx_socket_t) -1;

    if (c->shared) {
        return;
    }

    if (ngx_close_socket(fd) == -1) {

        err = ngx_socket_errno;

        if (err == NGX_ECONNRESET || err == NGX_ENOTCONN) {

            switch (log_error) {

            case NGX_ERROR_INFO:
                level = NGX_LOG_INFO;
                break;

            case NGX_ERROR_ERR:
                level = NGX_LOG_ERR;
                break;

            default:
                level = NGX_LOG_CRIT;
            }

        } else {
            level = NGX_LOG_CRIT;
        }

        ngx_log_error(level, c->log, err, ngx_close_socket_n " %d failed", fd);
    }
}


void
ngx_reusable_connection(ngx_connection_t *c, ngx_uint_t reusable)
{
    ngx_log_debug1(NGX_LOG_DEBUG_CORE, c->log, 0,
                   "reusable connection: %ui", reusable);

    if (c->reusable) {
        ngx_queue_remove(&c->queue);
        ngx_cycle->reusable_connections_n--;

#if (NGX_STAT_STUB)
        (void) ngx_atomic_fetch_add(ngx_stat_waiting, -1);
#endif
    }

    c->reusable = reusable;

    if (reusable) {
        /* need cast as ngx_cycle is volatile */

        ngx_queue_insert_head(
            (ngx_queue_t *) &ngx_cycle->reusable_connections_queue, &c->queue);
        ngx_cycle->reusable_connections_n++;

#if (NGX_STAT_STUB)
        (void) ngx_atomic_fetch_add(ngx_stat_waiting, 1);
#endif
    }
}


static void
ngx_drain_connections(ngx_cycle_t *cycle)
{
    ngx_uint_t         i, n;
    ngx_queue_t       *q;
    ngx_connection_t  *c;

    n = ngx_max(ngx_min(32, cycle->reusable_connections_n / 8), 1);

    for (i = 0; i < n; i++) {
        if (ngx_queue_empty(&cycle->reusable_connections_queue)) {
            break;
        }

        q = ngx_queue_last(&cycle->reusable_connections_queue);
        c = ngx_queue_data(q, ngx_connection_t, queue);

        ngx_log_debug0(NGX_LOG_DEBUG_CORE, c->log, 0,
                       "reusing connection");

        c->close = 1;
        c->read->handler(c->read);
    }
}


void
ngx_close_idle_connections(ngx_cycle_t *cycle)
{
    ngx_uint_t         i;
    ngx_connection_t  *c;

    c = cycle->connections;

    for (i = 0; i < cycle->connection_n; i++) {

        /* THREAD: lock */

        if (c[i].fd != (ngx_socket_t) -1 && c[i].idle) {
            c[i].close = 1;
            c[i].read->handler(c[i].read);
        }
    }
}


ngx_int_t
ngx_connection_local_sockaddr(ngx_connection_t *c, ngx_str_t *s,
    ngx_uint_t port)
{
    socklen_t             len;
    ngx_uint_t            addr;
    ngx_sockaddr_t        sa;
    struct sockaddr_in   *sin;
#if (NGX_HAVE_INET6)
    ngx_uint_t            i;
    struct sockaddr_in6  *sin6;
#endif

    addr = 0;

    if (c->local_socklen) {
        switch (c->local_sockaddr->sa_family) {

#if (NGX_HAVE_INET6)
        case AF_INET6:
            sin6 = (struct sockaddr_in6 *) c->local_sockaddr;

            for (i = 0; addr == 0 && i < 16; i++) {
                addr |= sin6->sin6_addr.s6_addr[i];
            }

            break;
#endif

#if (NGX_HAVE_UNIX_DOMAIN)
        case AF_UNIX:
            addr = 1;
            break;
#endif

        default: /* AF_INET */
            sin = (struct sockaddr_in *) c->local_sockaddr;
            addr = sin->sin_addr.s_addr;
            break;
        }
    }

    if (addr == 0) {

        len = sizeof(ngx_sockaddr_t);

        if (getsockname(c->fd, &sa.sockaddr, &len) == -1) {
            ngx_connection_error(c, ngx_socket_errno, "getsockname() failed");
            return NGX_ERROR;
        }

        c->local_sockaddr = ngx_palloc(c->pool, len);
        if (c->local_sockaddr == NULL) {
            return NGX_ERROR;
        }

        ngx_memcpy(c->local_sockaddr, &sa, len);

        c->local_socklen = len;
    }

    if (s == NULL) {
        return NGX_OK;
    }

    s->len = ngx_sock_ntop(c->local_sockaddr, c->local_socklen,
                           s->data, s->len, port);

    return NGX_OK;
}


ngx_int_t
ngx_tcp_nodelay(ngx_connection_t *c)
{
    int  tcp_nodelay;

    if (c->tcp_nodelay != NGX_TCP_NODELAY_UNSET) {
        return NGX_OK;
    }

    ngx_log_debug0(NGX_LOG_DEBUG_CORE, c->log, 0, "tcp_nodelay");

    tcp_nodelay = 1;

    if (setsockopt(c->fd, IPPROTO_TCP, TCP_NODELAY,
                   (const void *) &tcp_nodelay, sizeof(int))
        == -1)
    {
#if (NGX_SOLARIS)
        if (c->log_error == NGX_ERROR_INFO) {

            /* Solaris returns EINVAL if a socket has been shut down */
            c->log_error = NGX_ERROR_IGNORE_EINVAL;

            ngx_connection_error(c, ngx_socket_errno,
                                 "setsockopt(TCP_NODELAY) failed");

            c->log_error = NGX_ERROR_INFO;

            return NGX_ERROR;
        }
#endif

        ngx_connection_error(c, ngx_socket_errno,
                             "setsockopt(TCP_NODELAY) failed");
        return NGX_ERROR;
    }

    c->tcp_nodelay = NGX_TCP_NODELAY_SET;

    return NGX_OK;
}


ngx_int_t
ngx_connection_error(ngx_connection_t *c, ngx_err_t err, char *text)
{
    ngx_uint_t  level;

    /* Winsock may return NGX_ECONNABORTED instead of NGX_ECONNRESET */

    if ((err == NGX_ECONNRESET
#if (NGX_WIN32)
         || err == NGX_ECONNABORTED
#endif
        ) && c->log_error == NGX_ERROR_IGNORE_ECONNRESET)
    {
        return 0;
    }

#if (NGX_SOLARIS)
    if (err == NGX_EINVAL && c->log_error == NGX_ERROR_IGNORE_EINVAL) {
        return 0;
    }
#endif

    if (err == 0
        || err == NGX_ECONNRESET
#if (NGX_WIN32)
        || err == NGX_ECONNABORTED
#else
        || err == NGX_EPIPE
#endif
        || err == NGX_ENOTCONN
        || err == NGX_ETIMEDOUT
        || err == NGX_ECONNREFUSED
        || err == NGX_ENETDOWN
        || err == NGX_ENETUNREACH
        || err == NGX_EHOSTDOWN
        || err == NGX_EHOSTUNREACH)
    {
        switch (c->log_error) {

        case NGX_ERROR_IGNORE_EINVAL:
        case NGX_ERROR_IGNORE_ECONNRESET:
        case NGX_ERROR_INFO:
            level = NGX_LOG_INFO;
            break;

        default:
            level = NGX_LOG_ERR;
        }

    } else {
        level = NGX_LOG_ALERT;
    }

    ngx_log_error(level, c->log, err, text);

    return NGX_ERROR;
}