Mercurial > hg > nginx-quic

view src/stream/ngx_stream_upstream_round_robin.c @ 7525:575480d3fd01

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Perl: propagate errors. When an error happens, the ctx->error bit is now set, and croak() is called to terminate further processing. The ctx->error bit is checked in ngx_http_perl_call_handler() to cancel further processing, and is also checked in various output functions - to make sure these won't be called if croak() was handled by an eval{} in perl code. In particular, this ensures that output chain won't be called after errors, as filters might not expect this to happen. This fixes some segmentation faults under low memory conditions. Also this stops request processing after filter finalization or request body reading errors. For cases where an HTTP error status can be additionally returned (for example, 416 (Requested Range Not Satisfiable) from the range filter), the ctx->status field is also added.
author Maxim Dounin <mdounin@mdounin.ru>
date Fri, 12 Jul 2019 13:56:21 +0300
parents b99cbafd51da
children 90cc7194e993
line wrap: on
line source


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


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


#define ngx_stream_upstream_tries(p) ((p)->number                             \
                                      + ((p)->next ? (p)->next->number : 0))


static ngx_stream_upstream_rr_peer_t *ngx_stream_upstream_get_peer(
    ngx_stream_upstream_rr_peer_data_t *rrp);
static void ngx_stream_upstream_notify_round_robin_peer(
    ngx_peer_connection_t *pc, void *data, ngx_uint_t state);

#if (NGX_STREAM_SSL)

static ngx_int_t ngx_stream_upstream_set_round_robin_peer_session(
    ngx_peer_connection_t *pc, void *data);
static void ngx_stream_upstream_save_round_robin_peer_session(
    ngx_peer_connection_t *pc, void *data);
static ngx_int_t ngx_stream_upstream_empty_set_session(
    ngx_peer_connection_t *pc, void *data);
static void ngx_stream_upstream_empty_save_session(ngx_peer_connection_t *pc,
    void *data);

#endif


ngx_int_t
ngx_stream_upstream_init_round_robin(ngx_conf_t *cf,
    ngx_stream_upstream_srv_conf_t *us)
{
    ngx_url_t                        u;
    ngx_uint_t                       i, j, n, w;
    ngx_stream_upstream_server_t    *server;
    ngx_stream_upstream_rr_peer_t   *peer, **peerp;
    ngx_stream_upstream_rr_peers_t  *peers, *backup;

    us->peer.init = ngx_stream_upstream_init_round_robin_peer;

    if (us->servers) {
        server = us->servers->elts;

        n = 0;
        w = 0;

        for (i = 0; i < us->servers->nelts; i++) {
            if (server[i].backup) {
                continue;
            }

            n += server[i].naddrs;
            w += server[i].naddrs * server[i].weight;
        }

        if (n == 0) {
            ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                          "no servers in upstream \"%V\" in %s:%ui",
                          &us->host, us->file_name, us->line);
            return NGX_ERROR;
        }

        peers = ngx_pcalloc(cf->pool, sizeof(ngx_stream_upstream_rr_peers_t));
        if (peers == NULL) {
            return NGX_ERROR;
        }

        peer = ngx_pcalloc(cf->pool, sizeof(ngx_stream_upstream_rr_peer_t) * n);
        if (peer == NULL) {
            return NGX_ERROR;
        }

        peers->single = (n == 1);
        peers->number = n;
        peers->weighted = (w != n);
        peers->total_weight = w;
        peers->name = &us->host;

        n = 0;
        peerp = &peers->peer;

        for (i = 0; i < us->servers->nelts; i++) {
            if (server[i].backup) {
                continue;
            }

            for (j = 0; j < server[i].naddrs; j++) {
                peer[n].sockaddr = server[i].addrs[j].sockaddr;
                peer[n].socklen = server[i].addrs[j].socklen;
                peer[n].name = server[i].addrs[j].name;
                peer[n].weight = server[i].weight;
                peer[n].effective_weight = server[i].weight;
                peer[n].current_weight = 0;
                peer[n].max_conns = server[i].max_conns;
                peer[n].max_fails = server[i].max_fails;
                peer[n].fail_timeout = server[i].fail_timeout;
                peer[n].down = server[i].down;
                peer[n].server = server[i].name;

                *peerp = &peer[n];
                peerp = &peer[n].next;
                n++;
            }
        }

        us->peer.data = peers;

        /* backup servers */

        n = 0;
        w = 0;

        for (i = 0; i < us->servers->nelts; i++) {
            if (!server[i].backup) {
                continue;
            }

            n += server[i].naddrs;
            w += server[i].naddrs * server[i].weight;
        }

        if (n == 0) {
            return NGX_OK;
        }

        backup = ngx_pcalloc(cf->pool, sizeof(ngx_stream_upstream_rr_peers_t));
        if (backup == NULL) {
            return NGX_ERROR;
        }

        peer = ngx_pcalloc(cf->pool, sizeof(ngx_stream_upstream_rr_peer_t) * n);
        if (peer == NULL) {
            return NGX_ERROR;
        }

        peers->single = 0;
        backup->single = 0;
        backup->number = n;
        backup->weighted = (w != n);
        backup->total_weight = w;
        backup->name = &us->host;

        n = 0;
        peerp = &backup->peer;

        for (i = 0; i < us->servers->nelts; i++) {
            if (!server[i].backup) {
                continue;
            }

            for (j = 0; j < server[i].naddrs; j++) {
                peer[n].sockaddr = server[i].addrs[j].sockaddr;
                peer[n].socklen = server[i].addrs[j].socklen;
                peer[n].name = server[i].addrs[j].name;
                peer[n].weight = server[i].weight;
                peer[n].effective_weight = server[i].weight;
                peer[n].current_weight = 0;
                peer[n].max_conns = server[i].max_conns;
                peer[n].max_fails = server[i].max_fails;
                peer[n].fail_timeout = server[i].fail_timeout;
                peer[n].down = server[i].down;
                peer[n].server = server[i].name;

                *peerp = &peer[n];
                peerp = &peer[n].next;
                n++;
            }
        }

        peers->next = backup;

        return NGX_OK;
    }


    /* an upstream implicitly defined by proxy_pass, etc. */

    if (us->port == 0) {
        ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                      "no port in upstream \"%V\" in %s:%ui",
                      &us->host, us->file_name, us->line);
        return NGX_ERROR;
    }

    ngx_memzero(&u, sizeof(ngx_url_t));

    u.host = us->host;
    u.port = us->port;

    if (ngx_inet_resolve_host(cf->pool, &u) != NGX_OK) {
        if (u.err) {
            ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                          "%s in upstream \"%V\" in %s:%ui",
                          u.err, &us->host, us->file_name, us->line);
        }

        return NGX_ERROR;
    }

    n = u.naddrs;

    peers = ngx_pcalloc(cf->pool, sizeof(ngx_stream_upstream_rr_peers_t));
    if (peers == NULL) {
        return NGX_ERROR;
    }

    peer = ngx_pcalloc(cf->pool, sizeof(ngx_stream_upstream_rr_peer_t) * n);
    if (peer == NULL) {
        return NGX_ERROR;
    }

    peers->single = (n == 1);
    peers->number = n;
    peers->weighted = 0;
    peers->total_weight = n;
    peers->name = &us->host;

    peerp = &peers->peer;

    for (i = 0; i < u.naddrs; i++) {
        peer[i].sockaddr = u.addrs[i].sockaddr;
        peer[i].socklen = u.addrs[i].socklen;
        peer[i].name = u.addrs[i].name;
        peer[i].weight = 1;
        peer[i].effective_weight = 1;
        peer[i].current_weight = 0;
        peer[i].max_conns = 0;
        peer[i].max_fails = 1;
        peer[i].fail_timeout = 10;
        *peerp = &peer[i];
        peerp = &peer[i].next;
    }

    us->peer.data = peers;

    /* implicitly defined upstream has no backup servers */

    return NGX_OK;
}


ngx_int_t
ngx_stream_upstream_init_round_robin_peer(ngx_stream_session_t *s,
    ngx_stream_upstream_srv_conf_t *us)
{
    ngx_uint_t                           n;
    ngx_stream_upstream_rr_peer_data_t  *rrp;

    rrp = s->upstream->peer.data;

    if (rrp == NULL) {
        rrp = ngx_palloc(s->connection->pool,
                         sizeof(ngx_stream_upstream_rr_peer_data_t));
        if (rrp == NULL) {
            return NGX_ERROR;
        }

        s->upstream->peer.data = rrp;
    }

    rrp->peers = us->peer.data;
    rrp->current = NULL;
    rrp->config = 0;

    n = rrp->peers->number;

    if (rrp->peers->next && rrp->peers->next->number > n) {
        n = rrp->peers->next->number;
    }

    if (n <= 8 * sizeof(uintptr_t)) {
        rrp->tried = &rrp->data;
        rrp->data = 0;

    } else {
        n = (n + (8 * sizeof(uintptr_t) - 1)) / (8 * sizeof(uintptr_t));

        rrp->tried = ngx_pcalloc(s->connection->pool, n * sizeof(uintptr_t));
        if (rrp->tried == NULL) {
            return NGX_ERROR;
        }
    }

    s->upstream->peer.get = ngx_stream_upstream_get_round_robin_peer;
    s->upstream->peer.free = ngx_stream_upstream_free_round_robin_peer;
    s->upstream->peer.notify = ngx_stream_upstream_notify_round_robin_peer;
    s->upstream->peer.tries = ngx_stream_upstream_tries(rrp->peers);
#if (NGX_STREAM_SSL)
    s->upstream->peer.set_session =
                             ngx_stream_upstream_set_round_robin_peer_session;
    s->upstream->peer.save_session =
                             ngx_stream_upstream_save_round_robin_peer_session;
#endif

    return NGX_OK;
}


ngx_int_t
ngx_stream_upstream_create_round_robin_peer(ngx_stream_session_t *s,
    ngx_stream_upstream_resolved_t *ur)
{
    u_char                              *p;
    size_t                               len;
    socklen_t                            socklen;
    ngx_uint_t                           i, n;
    struct sockaddr                     *sockaddr;
    ngx_stream_upstream_rr_peer_t       *peer, **peerp;
    ngx_stream_upstream_rr_peers_t      *peers;
    ngx_stream_upstream_rr_peer_data_t  *rrp;

    rrp = s->upstream->peer.data;

    if (rrp == NULL) {
        rrp = ngx_palloc(s->connection->pool,
                         sizeof(ngx_stream_upstream_rr_peer_data_t));
        if (rrp == NULL) {
            return NGX_ERROR;
        }

        s->upstream->peer.data = rrp;
    }

    peers = ngx_pcalloc(s->connection->pool,
                        sizeof(ngx_stream_upstream_rr_peers_t));
    if (peers == NULL) {
        return NGX_ERROR;
    }

    peer = ngx_pcalloc(s->connection->pool,
                       sizeof(ngx_stream_upstream_rr_peer_t) * ur->naddrs);
    if (peer == NULL) {
        return NGX_ERROR;
    }

    peers->single = (ur->naddrs == 1);
    peers->number = ur->naddrs;
    peers->name = &ur->host;

    if (ur->sockaddr) {
        peer[0].sockaddr = ur->sockaddr;
        peer[0].socklen = ur->socklen;
        peer[0].name = ur->name;
        peer[0].weight = 1;
        peer[0].effective_weight = 1;
        peer[0].current_weight = 0;
        peer[0].max_conns = 0;
        peer[0].max_fails = 1;
        peer[0].fail_timeout = 10;
        peers->peer = peer;

    } else {
        peerp = &peers->peer;

        for (i = 0; i < ur->naddrs; i++) {

            socklen = ur->addrs[i].socklen;

            sockaddr = ngx_palloc(s->connection->pool, socklen);
            if (sockaddr == NULL) {
                return NGX_ERROR;
            }

            ngx_memcpy(sockaddr, ur->addrs[i].sockaddr, socklen);
            ngx_inet_set_port(sockaddr, ur->port);

            p = ngx_pnalloc(s->connection->pool, NGX_SOCKADDR_STRLEN);
            if (p == NULL) {
                return NGX_ERROR;
            }

            len = ngx_sock_ntop(sockaddr, socklen, p, NGX_SOCKADDR_STRLEN, 1);

            peer[i].sockaddr = sockaddr;
            peer[i].socklen = socklen;
            peer[i].name.len = len;
            peer[i].name.data = p;
            peer[i].weight = 1;
            peer[i].effective_weight = 1;
            peer[i].current_weight = 0;
            peer[i].max_conns = 0;
            peer[i].max_fails = 1;
            peer[i].fail_timeout = 10;
            *peerp = &peer[i];
            peerp = &peer[i].next;
        }
    }

    rrp->peers = peers;
    rrp->current = NULL;
    rrp->config = 0;

    if (rrp->peers->number <= 8 * sizeof(uintptr_t)) {
        rrp->tried = &rrp->data;
        rrp->data = 0;

    } else {
        n = (rrp->peers->number + (8 * sizeof(uintptr_t) - 1))
                / (8 * sizeof(uintptr_t));

        rrp->tried = ngx_pcalloc(s->connection->pool, n * sizeof(uintptr_t));
        if (rrp->tried == NULL) {
            return NGX_ERROR;
        }
    }

    s->upstream->peer.get = ngx_stream_upstream_get_round_robin_peer;
    s->upstream->peer.free = ngx_stream_upstream_free_round_robin_peer;
    s->upstream->peer.tries = ngx_stream_upstream_tries(rrp->peers);
#if (NGX_STREAM_SSL)
    s->upstream->peer.set_session = ngx_stream_upstream_empty_set_session;
    s->upstream->peer.save_session = ngx_stream_upstream_empty_save_session;
#endif

    return NGX_OK;
}


ngx_int_t
ngx_stream_upstream_get_round_robin_peer(ngx_peer_connection_t *pc, void *data)
{
    ngx_stream_upstream_rr_peer_data_t *rrp = data;

    ngx_int_t                        rc;
    ngx_uint_t                       i, n;
    ngx_stream_upstream_rr_peer_t   *peer;
    ngx_stream_upstream_rr_peers_t  *peers;

    ngx_log_debug1(NGX_LOG_DEBUG_STREAM, pc->log, 0,
                   "get rr peer, try: %ui", pc->tries);

    pc->connection = NULL;

    peers = rrp->peers;
    ngx_stream_upstream_rr_peers_wlock(peers);

    if (peers->single) {
        peer = peers->peer;

        if (peer->down) {
            goto failed;
        }

        if (peer->max_conns && peer->conns >= peer->max_conns) {
            goto failed;
        }

        rrp->current = peer;

    } else {

        /* there are several peers */

        peer = ngx_stream_upstream_get_peer(rrp);

        if (peer == NULL) {
            goto failed;
        }

        ngx_log_debug2(NGX_LOG_DEBUG_STREAM, pc->log, 0,
                       "get rr peer, current: %p %i",
                       peer, peer->current_weight);
    }

    pc->sockaddr = peer->sockaddr;
    pc->socklen = peer->socklen;
    pc->name = &peer->name;

    peer->conns++;

    ngx_stream_upstream_rr_peers_unlock(peers);

    return NGX_OK;

failed:

    if (peers->next) {

        ngx_log_debug0(NGX_LOG_DEBUG_STREAM, pc->log, 0, "backup servers");

        rrp->peers = peers->next;

        n = (rrp->peers->number + (8 * sizeof(uintptr_t) - 1))
                / (8 * sizeof(uintptr_t));

        for (i = 0; i < n; i++) {
            rrp->tried[i] = 0;
        }

        ngx_stream_upstream_rr_peers_unlock(peers);

        rc = ngx_stream_upstream_get_round_robin_peer(pc, rrp);

        if (rc != NGX_BUSY) {
            return rc;
        }

        ngx_stream_upstream_rr_peers_wlock(peers);
    }

    ngx_stream_upstream_rr_peers_unlock(peers);

    pc->name = peers->name;

    return NGX_BUSY;
}


static ngx_stream_upstream_rr_peer_t *
ngx_stream_upstream_get_peer(ngx_stream_upstream_rr_peer_data_t *rrp)
{
    time_t                          now;
    uintptr_t                       m;
    ngx_int_t                       total;
    ngx_uint_t                      i, n, p;
    ngx_stream_upstream_rr_peer_t  *peer, *best;

    now = ngx_time();

    best = NULL;
    total = 0;

#if (NGX_SUPPRESS_WARN)
    p = 0;
#endif

    for (peer = rrp->peers->peer, i = 0;
         peer;
         peer = peer->next, i++)
    {
        n = i / (8 * sizeof(uintptr_t));
        m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t));

        if (rrp->tried[n] & m) {
            continue;
        }

        if (peer->down) {
            continue;
        }

        if (peer->max_fails
            && peer->fails >= peer->max_fails
            && now - peer->checked <= peer->fail_timeout)
        {
            continue;
        }

        if (peer->max_conns && peer->conns >= peer->max_conns) {
            continue;
        }

        peer->current_weight += peer->effective_weight;
        total += peer->effective_weight;

        if (peer->effective_weight < peer->weight) {
            peer->effective_weight++;
        }

        if (best == NULL || peer->current_weight > best->current_weight) {
            best = peer;
            p = i;
        }
    }

    if (best == NULL) {
        return NULL;
    }

    rrp->current = best;

    n = p / (8 * sizeof(uintptr_t));
    m = (uintptr_t) 1 << p % (8 * sizeof(uintptr_t));

    rrp->tried[n] |= m;

    best->current_weight -= total;

    if (now - best->checked > best->fail_timeout) {
        best->checked = now;
    }

    return best;
}


void
ngx_stream_upstream_free_round_robin_peer(ngx_peer_connection_t *pc, void *data,
    ngx_uint_t state)
{
    ngx_stream_upstream_rr_peer_data_t  *rrp = data;

    time_t                          now;
    ngx_stream_upstream_rr_peer_t  *peer;

    ngx_log_debug2(NGX_LOG_DEBUG_STREAM, pc->log, 0,
                   "free rr peer %ui %ui", pc->tries, state);

    peer = rrp->current;

    ngx_stream_upstream_rr_peers_rlock(rrp->peers);
    ngx_stream_upstream_rr_peer_lock(rrp->peers, peer);

    if (rrp->peers->single) {
        peer->conns--;

        ngx_stream_upstream_rr_peer_unlock(rrp->peers, peer);
        ngx_stream_upstream_rr_peers_unlock(rrp->peers);

        pc->tries = 0;
        return;
    }

    if (state & NGX_PEER_FAILED) {
        now = ngx_time();

        peer->fails++;
        peer->accessed = now;
        peer->checked = now;

        if (peer->max_fails) {
            peer->effective_weight -= peer->weight / peer->max_fails;

            if (peer->fails >= peer->max_fails) {
                ngx_log_error(NGX_LOG_WARN, pc->log, 0,
                              "upstream server temporarily disabled");
            }
        }

        ngx_log_debug2(NGX_LOG_DEBUG_STREAM, pc->log, 0,
                       "free rr peer failed: %p %i",
                       peer, peer->effective_weight);

        if (peer->effective_weight < 0) {
            peer->effective_weight = 0;
        }

    } else {

        /* mark peer live if check passed */

        if (peer->accessed < peer->checked) {
            peer->fails = 0;
        }
    }

    peer->conns--;

    ngx_stream_upstream_rr_peer_unlock(rrp->peers, peer);
    ngx_stream_upstream_rr_peers_unlock(rrp->peers);

    if (pc->tries) {
        pc->tries--;
    }
}


static void
ngx_stream_upstream_notify_round_robin_peer(ngx_peer_connection_t *pc,
    void *data, ngx_uint_t type)
{
    ngx_stream_upstream_rr_peer_data_t  *rrp = data;

    ngx_stream_upstream_rr_peer_t  *peer;

    peer = rrp->current;

    if (type == NGX_STREAM_UPSTREAM_NOTIFY_CONNECT
        && pc->connection->type == SOCK_STREAM)
    {
        ngx_stream_upstream_rr_peers_rlock(rrp->peers);
        ngx_stream_upstream_rr_peer_lock(rrp->peers, peer);

        if (peer->accessed < peer->checked) {
            peer->fails = 0;
        }

        ngx_stream_upstream_rr_peer_unlock(rrp->peers, peer);
        ngx_stream_upstream_rr_peers_unlock(rrp->peers);
    }
}


#if (NGX_STREAM_SSL)

static ngx_int_t
ngx_stream_upstream_set_round_robin_peer_session(ngx_peer_connection_t *pc,
    void *data)
{
    ngx_stream_upstream_rr_peer_data_t  *rrp = data;

    ngx_int_t                        rc;
    ngx_ssl_session_t               *ssl_session;
    ngx_stream_upstream_rr_peer_t   *peer;
#if (NGX_STREAM_UPSTREAM_ZONE)
    int                              len;
    const u_char                    *p;
    ngx_stream_upstream_rr_peers_t  *peers;
    u_char                           buf[NGX_SSL_MAX_SESSION_SIZE];
#endif

    peer = rrp->current;

#if (NGX_STREAM_UPSTREAM_ZONE)
    peers = rrp->peers;

    if (peers->shpool) {
        ngx_stream_upstream_rr_peers_rlock(peers);
        ngx_stream_upstream_rr_peer_lock(peers, peer);

        if (peer->ssl_session == NULL) {
            ngx_stream_upstream_rr_peer_unlock(peers, peer);
            ngx_stream_upstream_rr_peers_unlock(peers);
            return NGX_OK;
        }

        len = peer->ssl_session_len;

        ngx_memcpy(buf, peer->ssl_session, len);

        ngx_stream_upstream_rr_peer_unlock(peers, peer);
        ngx_stream_upstream_rr_peers_unlock(peers);

        p = buf;
        ssl_session = d2i_SSL_SESSION(NULL, &p, len);

        rc = ngx_ssl_set_session(pc->connection, ssl_session);

        ngx_log_debug1(NGX_LOG_DEBUG_STREAM, pc->log, 0,
                       "set session: %p", ssl_session);

        ngx_ssl_free_session(ssl_session);

        return rc;
    }
#endif

    ssl_session = peer->ssl_session;

    rc = ngx_ssl_set_session(pc->connection, ssl_session);

    ngx_log_debug1(NGX_LOG_DEBUG_STREAM, pc->log, 0,
                   "set session: %p", ssl_session);

    return rc;
}


static void
ngx_stream_upstream_save_round_robin_peer_session(ngx_peer_connection_t *pc,
    void *data)
{
    ngx_stream_upstream_rr_peer_data_t  *rrp = data;

    ngx_ssl_session_t               *old_ssl_session, *ssl_session;
    ngx_stream_upstream_rr_peer_t   *peer;
#if (NGX_STREAM_UPSTREAM_ZONE)
    int                              len;
    u_char                          *p;
    ngx_stream_upstream_rr_peers_t  *peers;
    u_char                           buf[NGX_SSL_MAX_SESSION_SIZE];
#endif

#if (NGX_STREAM_UPSTREAM_ZONE)
    peers = rrp->peers;

    if (peers->shpool) {

        ssl_session = ngx_ssl_get0_session(pc->connection);

        if (ssl_session == NULL) {
            return;
        }

        ngx_log_debug1(NGX_LOG_DEBUG_STREAM, pc->log, 0,
                       "save session: %p", ssl_session);

        len = i2d_SSL_SESSION(ssl_session, NULL);

        /* do not cache too big session */

        if (len > NGX_SSL_MAX_SESSION_SIZE) {
            return;
        }

        p = buf;
        (void) i2d_SSL_SESSION(ssl_session, &p);

        peer = rrp->current;

        ngx_stream_upstream_rr_peers_rlock(peers);
        ngx_stream_upstream_rr_peer_lock(peers, peer);

        if (len > peer->ssl_session_len) {
            ngx_shmtx_lock(&peers->shpool->mutex);

            if (peer->ssl_session) {
                ngx_slab_free_locked(peers->shpool, peer->ssl_session);
            }

            peer->ssl_session = ngx_slab_alloc_locked(peers->shpool, len);

            ngx_shmtx_unlock(&peers->shpool->mutex);

            if (peer->ssl_session == NULL) {
                peer->ssl_session_len = 0;

                ngx_stream_upstream_rr_peer_unlock(peers, peer);
                ngx_stream_upstream_rr_peers_unlock(peers);
                return;
            }

            peer->ssl_session_len = len;
        }

        ngx_memcpy(peer->ssl_session, buf, len);

        ngx_stream_upstream_rr_peer_unlock(peers, peer);
        ngx_stream_upstream_rr_peers_unlock(peers);

        return;
    }
#endif

    ssl_session = ngx_ssl_get_session(pc->connection);

    if (ssl_session == NULL) {
        return;
    }

    ngx_log_debug1(NGX_LOG_DEBUG_STREAM, pc->log, 0,
                   "save session: %p", ssl_session);

    peer = rrp->current;

    old_ssl_session = peer->ssl_session;
    peer->ssl_session = ssl_session;

    if (old_ssl_session) {

        ngx_log_debug1(NGX_LOG_DEBUG_STREAM, pc->log, 0,
                       "old session: %p", old_ssl_session);

        /* TODO: may block */

        ngx_ssl_free_session(old_ssl_session);
    }
}


static ngx_int_t
ngx_stream_upstream_empty_set_session(ngx_peer_connection_t *pc, void *data)
{
    return NGX_OK;
}


static void
ngx_stream_upstream_empty_save_session(ngx_peer_connection_t *pc, void *data)
{
    return;
}

#endif