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view src/event/ngx_event_accept.c @ 6749:f88a145b093e stable-1.10

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HTTP/2: the "421 Misdirected Request" response (closes #848). Since 4fbef397c753 nginx rejects with the 400 error any attempts of requesting different host over the same connection, if the relevant virtual server requires verification of a client certificate. While requesting hosts other than negotiated isn't something legal in HTTP/1.x, the HTTP/2 specification explicitly permits such requests for connection reuse and has introduced a special response code 421. According to RFC 7540 Section 9.1.2 this code can be sent by a server that is not configured to produce responses for the combination of scheme and authority that are included in the request URI. And the client may retry the request over a different connection. Now this code is used for requests that aren't authorized in current connection. After receiving the 421 response a client will be able to open a new connection, provide the required certificate and retry the request. Unfortunately, not all clients currently are able to handle it well. Notably Chrome just shows an error, while at least the latest version of Firefox retries the request over a new connection.
author Valentin Bartenev <vbart@nginx.com>
date Fri, 20 May 2016 18:41:17 +0300
parents 8f038068f4bc
children 2f98b5709d79
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>


static ngx_int_t ngx_enable_accept_events(ngx_cycle_t *cycle);
static ngx_int_t ngx_disable_accept_events(ngx_cycle_t *cycle, ngx_uint_t all);
static void ngx_close_accepted_connection(ngx_connection_t *c);
#if (NGX_DEBUG)
static void ngx_debug_accepted_connection(ngx_event_conf_t *ecf,
    ngx_connection_t *c);
#endif


void
ngx_event_accept(ngx_event_t *ev)
{
    socklen_t          socklen;
    ngx_err_t          err;
    ngx_log_t         *log;
    ngx_uint_t         level;
    ngx_socket_t       s;
    ngx_event_t       *rev, *wev;
    ngx_listening_t   *ls;
    ngx_connection_t  *c, *lc;
    ngx_event_conf_t  *ecf;
    u_char             sa[NGX_SOCKADDRLEN];
#if (NGX_HAVE_ACCEPT4)
    static ngx_uint_t  use_accept4 = 1;
#endif

    if (ev->timedout) {
        if (ngx_enable_accept_events((ngx_cycle_t *) ngx_cycle) != NGX_OK) {
            return;
        }

        ev->timedout = 0;
    }

    ecf = ngx_event_get_conf(ngx_cycle->conf_ctx, ngx_event_core_module);

    if (!(ngx_event_flags & NGX_USE_KQUEUE_EVENT)) {
        ev->available = ecf->multi_accept;
    }

    lc = ev->data;
    ls = lc->listening;
    ev->ready = 0;

    ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0,
                   "accept on %V, ready: %d", &ls->addr_text, ev->available);

    do {
        socklen = NGX_SOCKADDRLEN;

#if (NGX_HAVE_ACCEPT4)
        if (use_accept4) {
            s = accept4(lc->fd, (struct sockaddr *) sa, &socklen,
                        SOCK_NONBLOCK);
        } else {
            s = accept(lc->fd, (struct sockaddr *) sa, &socklen);
        }
#else
        s = accept(lc->fd, (struct sockaddr *) sa, &socklen);
#endif

        if (s == (ngx_socket_t) -1) {
            err = ngx_socket_errno;

            if (err == NGX_EAGAIN) {
                ngx_log_debug0(NGX_LOG_DEBUG_EVENT, ev->log, err,
                               "accept() not ready");
                return;
            }

            level = NGX_LOG_ALERT;

            if (err == NGX_ECONNABORTED) {
                level = NGX_LOG_ERR;

            } else if (err == NGX_EMFILE || err == NGX_ENFILE) {
                level = NGX_LOG_CRIT;
            }

#if (NGX_HAVE_ACCEPT4)
            ngx_log_error(level, ev->log, err,
                          use_accept4 ? "accept4() failed" : "accept() failed");

            if (use_accept4 && err == NGX_ENOSYS) {
                use_accept4 = 0;
                ngx_inherited_nonblocking = 0;
                continue;
            }
#else
            ngx_log_error(level, ev->log, err, "accept() failed");
#endif

            if (err == NGX_ECONNABORTED) {
                if (ngx_event_flags & NGX_USE_KQUEUE_EVENT) {
                    ev->available--;
                }

                if (ev->available) {
                    continue;
                }
            }

            if (err == NGX_EMFILE || err == NGX_ENFILE) {
                if (ngx_disable_accept_events((ngx_cycle_t *) ngx_cycle, 1)
                    != NGX_OK)
                {
                    return;
                }

                if (ngx_use_accept_mutex) {
                    if (ngx_accept_mutex_held) {
                        ngx_shmtx_unlock(&ngx_accept_mutex);
                        ngx_accept_mutex_held = 0;
                    }

                    ngx_accept_disabled = 1;

                } else {
                    ngx_add_timer(ev, ecf->accept_mutex_delay);
                }
            }

            return;
        }

#if (NGX_STAT_STUB)
        (void) ngx_atomic_fetch_add(ngx_stat_accepted, 1);
#endif

        ngx_accept_disabled = ngx_cycle->connection_n / 8
                              - ngx_cycle->free_connection_n;

        c = ngx_get_connection(s, ev->log);

        if (c == NULL) {
            if (ngx_close_socket(s) == -1) {
                ngx_log_error(NGX_LOG_ALERT, ev->log, ngx_socket_errno,
                              ngx_close_socket_n " failed");
            }

            return;
        }

        c->type = SOCK_STREAM;

#if (NGX_STAT_STUB)
        (void) ngx_atomic_fetch_add(ngx_stat_active, 1);
#endif

        c->pool = ngx_create_pool(ls->pool_size, ev->log);
        if (c->pool == NULL) {
            ngx_close_accepted_connection(c);
            return;
        }

        c->sockaddr = ngx_palloc(c->pool, socklen);
        if (c->sockaddr == NULL) {
            ngx_close_accepted_connection(c);
            return;
        }

        ngx_memcpy(c->sockaddr, sa, socklen);

        log = ngx_palloc(c->pool, sizeof(ngx_log_t));
        if (log == NULL) {
            ngx_close_accepted_connection(c);
            return;
        }

        /* set a blocking mode for iocp and non-blocking mode for others */

        if (ngx_inherited_nonblocking) {
            if (ngx_event_flags & NGX_USE_IOCP_EVENT) {
                if (ngx_blocking(s) == -1) {
                    ngx_log_error(NGX_LOG_ALERT, ev->log, ngx_socket_errno,
                                  ngx_blocking_n " failed");
                    ngx_close_accepted_connection(c);
                    return;
                }
            }

        } else {
            if (!(ngx_event_flags & NGX_USE_IOCP_EVENT)) {
                if (ngx_nonblocking(s) == -1) {
                    ngx_log_error(NGX_LOG_ALERT, ev->log, ngx_socket_errno,
                                  ngx_nonblocking_n " failed");
                    ngx_close_accepted_connection(c);
                    return;
                }
            }
        }

        *log = ls->log;

        c->recv = ngx_recv;
        c->send = ngx_send;
        c->recv_chain = ngx_recv_chain;
        c->send_chain = ngx_send_chain;

        c->log = log;
        c->pool->log = log;

        c->socklen = socklen;
        c->listening = ls;
        c->local_sockaddr = ls->sockaddr;
        c->local_socklen = ls->socklen;

        c->unexpected_eof = 1;

#if (NGX_HAVE_UNIX_DOMAIN)
        if (c->sockaddr->sa_family == AF_UNIX) {
            c->tcp_nopush = NGX_TCP_NOPUSH_DISABLED;
            c->tcp_nodelay = NGX_TCP_NODELAY_DISABLED;
#if (NGX_SOLARIS)
            /* Solaris's sendfilev() supports AF_NCA, AF_INET, and AF_INET6 */
            c->sendfile = 0;
#endif
        }
#endif

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

        wev->ready = 1;

        if (ngx_event_flags & NGX_USE_IOCP_EVENT) {
            rev->ready = 1;
        }

        if (ev->deferred_accept) {
            rev->ready = 1;
#if (NGX_HAVE_KQUEUE)
            rev->available = 1;
#endif
        }

        rev->log = log;
        wev->log = log;

        /*
         * TODO: MT: - ngx_atomic_fetch_add()
         *             or protection by critical section or light mutex
         *
         * TODO: MP: - allocated in a shared memory
         *           - ngx_atomic_fetch_add()
         *             or protection by critical section or light mutex
         */

        c->number = ngx_atomic_fetch_add(ngx_connection_counter, 1);

#if (NGX_STAT_STUB)
        (void) ngx_atomic_fetch_add(ngx_stat_handled, 1);
#endif

        if (ls->addr_ntop) {
            c->addr_text.data = ngx_pnalloc(c->pool, ls->addr_text_max_len);
            if (c->addr_text.data == NULL) {
                ngx_close_accepted_connection(c);
                return;
            }

            c->addr_text.len = ngx_sock_ntop(c->sockaddr, c->socklen,
                                             c->addr_text.data,
                                             ls->addr_text_max_len, 0);
            if (c->addr_text.len == 0) {
                ngx_close_accepted_connection(c);
                return;
            }
        }

#if (NGX_DEBUG)
        {
        ngx_str_t  addr;
        u_char     text[NGX_SOCKADDR_STRLEN];

        ngx_debug_accepted_connection(ecf, c);

        if (log->log_level & NGX_LOG_DEBUG_EVENT) {
            addr.data = text;
            addr.len = ngx_sock_ntop(c->sockaddr, c->socklen, text,
                                     NGX_SOCKADDR_STRLEN, 1);

            ngx_log_debug3(NGX_LOG_DEBUG_EVENT, log, 0,
                           "*%uA accept: %V fd:%d", c->number, &addr, s);
        }

        }
#endif

        if (ngx_add_conn && (ngx_event_flags & NGX_USE_EPOLL_EVENT) == 0) {
            if (ngx_add_conn(c) == NGX_ERROR) {
                ngx_close_accepted_connection(c);
                return;
            }
        }

        log->data = NULL;
        log->handler = NULL;

        ls->handler(c);

        if (ngx_event_flags & NGX_USE_KQUEUE_EVENT) {
            ev->available--;
        }

    } while (ev->available);
}


#if !(NGX_WIN32)

void
ngx_event_recvmsg(ngx_event_t *ev)
{
    ssize_t            n;
    ngx_log_t         *log;
    ngx_err_t          err;
    ngx_event_t       *rev, *wev;
    struct iovec       iov[1];
    struct msghdr      msg;
    ngx_listening_t   *ls;
    ngx_event_conf_t  *ecf;
    ngx_connection_t  *c, *lc;
    u_char             sa[NGX_SOCKADDRLEN];
    static u_char      buffer[65535];

#if (NGX_HAVE_MSGHDR_MSG_CONTROL)

#if (NGX_HAVE_IP_RECVDSTADDR)
    u_char             msg_control[CMSG_SPACE(sizeof(struct in_addr))];
#elif (NGX_HAVE_IP_PKTINFO)
    u_char             msg_control[CMSG_SPACE(sizeof(struct in_pktinfo))];
#endif

#if (NGX_HAVE_INET6 && NGX_HAVE_IPV6_RECVPKTINFO)
    u_char             msg_control6[CMSG_SPACE(sizeof(struct in6_pktinfo))];
#endif

#endif

    if (ev->timedout) {
        if (ngx_enable_accept_events((ngx_cycle_t *) ngx_cycle) != NGX_OK) {
            return;
        }

        ev->timedout = 0;
    }

    ecf = ngx_event_get_conf(ngx_cycle->conf_ctx, ngx_event_core_module);

    if (!(ngx_event_flags & NGX_USE_KQUEUE_EVENT)) {
        ev->available = ecf->multi_accept;
    }

    lc = ev->data;
    ls = lc->listening;
    ev->ready = 0;

    ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0,
                   "recvmsg on %V, ready: %d", &ls->addr_text, ev->available);

    do {
        ngx_memzero(&msg, sizeof(struct msghdr));

        iov[0].iov_base = (void *) buffer;
        iov[0].iov_len = sizeof(buffer);

        msg.msg_name = &sa;
        msg.msg_namelen = sizeof(sa);
        msg.msg_iov = iov;
        msg.msg_iovlen = 1;

#if (NGX_HAVE_MSGHDR_MSG_CONTROL)

        if (ls->wildcard) {

#if (NGX_HAVE_IP_RECVDSTADDR || NGX_HAVE_IP_PKTINFO)
            if (ls->sockaddr->sa_family == AF_INET) {
                msg.msg_control = &msg_control;
                msg.msg_controllen = sizeof(msg_control);
            }
#endif

#if (NGX_HAVE_INET6 && NGX_HAVE_IPV6_RECVPKTINFO)
            if (ls->sockaddr->sa_family == AF_INET6) {
                msg.msg_control = &msg_control6;
                msg.msg_controllen = sizeof(msg_control6);
            }
#endif
        }

#endif

        n = recvmsg(lc->fd, &msg, 0);

        if (n == -1) {
            err = ngx_socket_errno;

            if (err == NGX_EAGAIN) {
                ngx_log_debug0(NGX_LOG_DEBUG_EVENT, ev->log, err,
                               "recvmsg() not ready");
                return;
            }

            ngx_log_error(NGX_LOG_ALERT, ev->log, err, "recvmsg() failed");

            return;
        }

#if (NGX_STAT_STUB)
        (void) ngx_atomic_fetch_add(ngx_stat_accepted, 1);
#endif

#if (NGX_HAVE_MSGHDR_MSG_CONTROL)
        if (msg.msg_flags & (MSG_TRUNC|MSG_CTRUNC)) {
            ngx_log_error(NGX_LOG_ALERT, ev->log, 0,
                          "recvmsg() truncated data");
            continue;
        }
#endif

        ngx_accept_disabled = ngx_cycle->connection_n / 8
                              - ngx_cycle->free_connection_n;

        c = ngx_get_connection(lc->fd, ev->log);
        if (c == NULL) {
            return;
        }

        c->shared = 1;
        c->type = SOCK_DGRAM;
        c->socklen = msg.msg_namelen;

#if (NGX_STAT_STUB)
        (void) ngx_atomic_fetch_add(ngx_stat_active, 1);
#endif

        c->pool = ngx_create_pool(ls->pool_size, ev->log);
        if (c->pool == NULL) {
            ngx_close_accepted_connection(c);
            return;
        }

        c->sockaddr = ngx_palloc(c->pool, c->socklen);
        if (c->sockaddr == NULL) {
            ngx_close_accepted_connection(c);
            return;
        }

        ngx_memcpy(c->sockaddr, msg.msg_name, c->socklen);

        log = ngx_palloc(c->pool, sizeof(ngx_log_t));
        if (log == NULL) {
            ngx_close_accepted_connection(c);
            return;
        }

        *log = ls->log;

        c->send = ngx_udp_send;

        c->log = log;
        c->pool->log = log;

        c->listening = ls;
        c->local_sockaddr = ls->sockaddr;
        c->local_socklen = ls->socklen;

#if (NGX_HAVE_MSGHDR_MSG_CONTROL)

        if (ls->wildcard) {
            struct cmsghdr   *cmsg;
            struct sockaddr  *sockaddr;

            sockaddr = ngx_palloc(c->pool, c->local_socklen);
            if (sockaddr == NULL) {
                ngx_close_accepted_connection(c);
                return;
            }

            ngx_memcpy(sockaddr, c->local_sockaddr, c->local_socklen);
            c->local_sockaddr = sockaddr;

            for (cmsg = CMSG_FIRSTHDR(&msg);
                 cmsg != NULL;
                 cmsg = CMSG_NXTHDR(&msg, cmsg))
            {

#if (NGX_HAVE_IP_RECVDSTADDR)

                if (cmsg->cmsg_level == IPPROTO_IP
                    && cmsg->cmsg_type == IP_RECVDSTADDR
                    && sockaddr->sa_family == AF_INET)
                {
                    struct in_addr      *addr;
                    struct sockaddr_in  *sin;

                    addr = (struct in_addr *) CMSG_DATA(cmsg);
                    sin = (struct sockaddr_in *) sockaddr;
                    sin->sin_addr = *addr;

                    break;
                }

#elif (NGX_HAVE_IP_PKTINFO)

                if (cmsg->cmsg_level == IPPROTO_IP
                    && cmsg->cmsg_type == IP_PKTINFO
                    && sockaddr->sa_family == AF_INET)
                {
                    struct in_pktinfo   *pkt;
                    struct sockaddr_in  *sin;

                    pkt = (struct in_pktinfo *) CMSG_DATA(cmsg);
                    sin = (struct sockaddr_in *) sockaddr;
                    sin->sin_addr = pkt->ipi_addr;

                    break;
                }

#endif

#if (NGX_HAVE_INET6 && NGX_HAVE_IPV6_RECVPKTINFO)

                if (cmsg->cmsg_level == IPPROTO_IPV6
                    && cmsg->cmsg_type == IPV6_PKTINFO
                    && sockaddr->sa_family == AF_INET6)
                {
                    struct in6_pktinfo   *pkt6;
                    struct sockaddr_in6  *sin6;

                    pkt6 = (struct in6_pktinfo *) CMSG_DATA(cmsg);
                    sin6 = (struct sockaddr_in6 *) sockaddr;
                    sin6->sin6_addr = pkt6->ipi6_addr;

                    break;
                }

#endif

            }
        }

#endif

        c->buffer = ngx_create_temp_buf(c->pool, n);
        if (c->buffer == NULL) {
            ngx_close_accepted_connection(c);
            return;
        }

        c->buffer->last = ngx_cpymem(c->buffer->last, buffer, n);

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

        wev->ready = 1;

        rev->log = log;
        wev->log = log;

        /*
         * TODO: MT: - ngx_atomic_fetch_add()
         *             or protection by critical section or light mutex
         *
         * TODO: MP: - allocated in a shared memory
         *           - ngx_atomic_fetch_add()
         *             or protection by critical section or light mutex
         */

        c->number = ngx_atomic_fetch_add(ngx_connection_counter, 1);

#if (NGX_STAT_STUB)
        (void) ngx_atomic_fetch_add(ngx_stat_handled, 1);
#endif

        if (ls->addr_ntop) {
            c->addr_text.data = ngx_pnalloc(c->pool, ls->addr_text_max_len);
            if (c->addr_text.data == NULL) {
                ngx_close_accepted_connection(c);
                return;
            }

            c->addr_text.len = ngx_sock_ntop(c->sockaddr, c->socklen,
                                             c->addr_text.data,
                                             ls->addr_text_max_len, 0);
            if (c->addr_text.len == 0) {
                ngx_close_accepted_connection(c);
                return;
            }
        }

#if (NGX_DEBUG)
        {
        ngx_str_t  addr;
        u_char     text[NGX_SOCKADDR_STRLEN];

        ngx_debug_accepted_connection(ecf, c);

        if (log->log_level & NGX_LOG_DEBUG_EVENT) {
            addr.data = text;
            addr.len = ngx_sock_ntop(c->sockaddr, c->socklen, text,
                                     NGX_SOCKADDR_STRLEN, 1);

            ngx_log_debug4(NGX_LOG_DEBUG_EVENT, log, 0,
                           "*%uA recvmsg: %V fd:%d n:%z",
                           c->number, &addr, c->fd, n);
        }

        }
#endif

        log->data = NULL;
        log->handler = NULL;

        ls->handler(c);

        if (ngx_event_flags & NGX_USE_KQUEUE_EVENT) {
            ev->available -= n;
        }

    } while (ev->available);
}

#endif


ngx_int_t
ngx_trylock_accept_mutex(ngx_cycle_t *cycle)
{
    if (ngx_shmtx_trylock(&ngx_accept_mutex)) {

        ngx_log_debug0(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
                       "accept mutex locked");

        if (ngx_accept_mutex_held && ngx_accept_events == 0) {
            return NGX_OK;
        }

        if (ngx_enable_accept_events(cycle) == NGX_ERROR) {
            ngx_shmtx_unlock(&ngx_accept_mutex);
            return NGX_ERROR;
        }

        ngx_accept_events = 0;
        ngx_accept_mutex_held = 1;

        return NGX_OK;
    }

    ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
                   "accept mutex lock failed: %ui", ngx_accept_mutex_held);

    if (ngx_accept_mutex_held) {
        if (ngx_disable_accept_events(cycle, 0) == NGX_ERROR) {
            return NGX_ERROR;
        }

        ngx_accept_mutex_held = 0;
    }

    return NGX_OK;
}


static ngx_int_t
ngx_enable_accept_events(ngx_cycle_t *cycle)
{
    ngx_uint_t         i;
    ngx_listening_t   *ls;
    ngx_connection_t  *c;

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

        c = ls[i].connection;

        if (c == NULL || c->read->active) {
            continue;
        }

        if (ngx_add_event(c->read, NGX_READ_EVENT, 0) == NGX_ERROR) {
            return NGX_ERROR;
        }
    }

    return NGX_OK;
}


static ngx_int_t
ngx_disable_accept_events(ngx_cycle_t *cycle, ngx_uint_t all)
{
    ngx_uint_t         i;
    ngx_listening_t   *ls;
    ngx_connection_t  *c;

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

        c = ls[i].connection;

        if (c == NULL || !c->read->active) {
            continue;
        }

#if (NGX_HAVE_REUSEPORT)

        /*
         * do not disable accept on worker's own sockets
         * when disabling accept events due to accept mutex
         */

        if (ls[i].reuseport && !all) {
            continue;
        }

#endif

        if (ngx_del_event(c->read, NGX_READ_EVENT, NGX_DISABLE_EVENT)
            == NGX_ERROR)
        {
            return NGX_ERROR;
        }
    }

    return NGX_OK;
}


static void
ngx_close_accepted_connection(ngx_connection_t *c)
{
    ngx_socket_t  fd;

    ngx_free_connection(c);

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

    if (!c->shared && ngx_close_socket(fd) == -1) {
        ngx_log_error(NGX_LOG_ALERT, c->log, ngx_socket_errno,
                      ngx_close_socket_n " failed");
    }

    if (c->pool) {
        ngx_destroy_pool(c->pool);
    }

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


u_char *
ngx_accept_log_error(ngx_log_t *log, u_char *buf, size_t len)
{
    return ngx_snprintf(buf, len, " while accepting new connection on %V",
                        log->data);
}


#if (NGX_DEBUG)

static void
ngx_debug_accepted_connection(ngx_event_conf_t *ecf, ngx_connection_t *c)
{
    struct sockaddr_in   *sin;
    ngx_cidr_t           *cidr;
    ngx_uint_t            i;
#if (NGX_HAVE_INET6)
    struct sockaddr_in6  *sin6;
    ngx_uint_t            n;
#endif

    cidr = ecf->debug_connection.elts;
    for (i = 0; i < ecf->debug_connection.nelts; i++) {
        if (cidr[i].family != (ngx_uint_t) c->sockaddr->sa_family) {
            goto next;
        }

        switch (cidr[i].family) {

#if (NGX_HAVE_INET6)
        case AF_INET6:
            sin6 = (struct sockaddr_in6 *) c->sockaddr;
            for (n = 0; n < 16; n++) {
                if ((sin6->sin6_addr.s6_addr[n]
                    & cidr[i].u.in6.mask.s6_addr[n])
                    != cidr[i].u.in6.addr.s6_addr[n])
                {
                    goto next;
                }
            }
            break;
#endif

#if (NGX_HAVE_UNIX_DOMAIN)
        case AF_UNIX:
            break;
#endif

        default: /* AF_INET */
            sin = (struct sockaddr_in *) c->sockaddr;
            if ((sin->sin_addr.s_addr & cidr[i].u.in.mask)
                != cidr[i].u.in.addr)
            {
                goto next;
            }
            break;
        }

        c->log->log_level = NGX_LOG_DEBUG_CONNECTION|NGX_LOG_DEBUG_ALL;
        break;

    next:
        continue;
    }
}

#endif