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view src/stream/ngx_stream_upstream_hash_module.c @ 7354:1812f1d79d84

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Fixed socket leak with "return 444" in error_page (ticket #274). Socket leak was observed in the following configuration: error_page 400 = /close; location = /close { return 444; } The problem is that "return 444" triggers termination of the request, and due to error_page termination thinks that it needs to use a posted request to clear stack. But at the early request processing where 400 errors are generated there are no ngx_http_run_posted_requests() calls, so the request is only terminated after an external event. Variants of the problem include "error_page 497" instead (ticket #695) and various other errors generated during early request processing (405, 414, 421, 494, 495, 496, 501, 505). The same problem can be also triggered with "return 499" and "return 408" as both codes trigger ngx_http_terminate_request(), much like "return 444". To fix this, the patch adds ngx_http_run_posted_requests() calls to ngx_http_process_request_line() and ngx_http_process_request_headers() functions, and to ngx_http_v2_run_request() and ngx_http_v2_push_stream() functions in HTTP/2. Since the ngx_http_process_request() function is now only called via other functions which call ngx_http_run_posted_requests(), the call there is no longer needed and was removed.
author Maxim Dounin <mdounin@mdounin.ru>
date Fri, 21 Sep 2018 15:59:30 +0300
parents ed599ea6c1f1
children d964b0aee8e7
line wrap: on
line source


/*
 * Copyright (C) Roman Arutyunyan
 * Copyright (C) Nginx, Inc.
 */


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


typedef struct {
    uint32_t                              hash;
    ngx_str_t                            *server;
} ngx_stream_upstream_chash_point_t;


typedef struct {
    ngx_uint_t                            number;
    ngx_stream_upstream_chash_point_t     point[1];
} ngx_stream_upstream_chash_points_t;


typedef struct {
    ngx_stream_complex_value_t            key;
    ngx_stream_upstream_chash_points_t   *points;
} ngx_stream_upstream_hash_srv_conf_t;


typedef struct {
    /* the round robin data must be first */
    ngx_stream_upstream_rr_peer_data_t    rrp;
    ngx_stream_upstream_hash_srv_conf_t  *conf;
    ngx_str_t                             key;
    ngx_uint_t                            tries;
    ngx_uint_t                            rehash;
    uint32_t                              hash;
    ngx_event_get_peer_pt                 get_rr_peer;
} ngx_stream_upstream_hash_peer_data_t;


static ngx_int_t ngx_stream_upstream_init_hash(ngx_conf_t *cf,
    ngx_stream_upstream_srv_conf_t *us);
static ngx_int_t ngx_stream_upstream_init_hash_peer(ngx_stream_session_t *s,
    ngx_stream_upstream_srv_conf_t *us);
static ngx_int_t ngx_stream_upstream_get_hash_peer(ngx_peer_connection_t *pc,
    void *data);

static ngx_int_t ngx_stream_upstream_init_chash(ngx_conf_t *cf,
    ngx_stream_upstream_srv_conf_t *us);
static int ngx_libc_cdecl
    ngx_stream_upstream_chash_cmp_points(const void *one, const void *two);
static ngx_uint_t ngx_stream_upstream_find_chash_point(
    ngx_stream_upstream_chash_points_t *points, uint32_t hash);
static ngx_int_t ngx_stream_upstream_init_chash_peer(ngx_stream_session_t *s,
    ngx_stream_upstream_srv_conf_t *us);
static ngx_int_t ngx_stream_upstream_get_chash_peer(ngx_peer_connection_t *pc,
    void *data);

static void *ngx_stream_upstream_hash_create_conf(ngx_conf_t *cf);
static char *ngx_stream_upstream_hash(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);


static ngx_command_t  ngx_stream_upstream_hash_commands[] = {

    { ngx_string("hash"),
      NGX_STREAM_UPS_CONF|NGX_CONF_TAKE12,
      ngx_stream_upstream_hash,
      NGX_STREAM_SRV_CONF_OFFSET,
      0,
      NULL },

      ngx_null_command
};


static ngx_stream_module_t  ngx_stream_upstream_hash_module_ctx = {
    NULL,                                  /* preconfiguration */
    NULL,                                  /* postconfiguration */

    NULL,                                  /* create main configuration */
    NULL,                                  /* init main configuration */

    ngx_stream_upstream_hash_create_conf,  /* create server configuration */
    NULL                                   /* merge server configuration */
};


ngx_module_t  ngx_stream_upstream_hash_module = {
    NGX_MODULE_V1,
    &ngx_stream_upstream_hash_module_ctx,  /* module context */
    ngx_stream_upstream_hash_commands,     /* module directives */
    NGX_STREAM_MODULE,                     /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


static ngx_int_t
ngx_stream_upstream_init_hash(ngx_conf_t *cf,
    ngx_stream_upstream_srv_conf_t *us)
{
    if (ngx_stream_upstream_init_round_robin(cf, us) != NGX_OK) {
        return NGX_ERROR;
    }

    us->peer.init = ngx_stream_upstream_init_hash_peer;

    return NGX_OK;
}


static ngx_int_t
ngx_stream_upstream_init_hash_peer(ngx_stream_session_t *s,
    ngx_stream_upstream_srv_conf_t *us)
{
    ngx_stream_upstream_hash_srv_conf_t   *hcf;
    ngx_stream_upstream_hash_peer_data_t  *hp;

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

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

    if (ngx_stream_upstream_init_round_robin_peer(s, us) != NGX_OK) {
        return NGX_ERROR;
    }

    s->upstream->peer.get = ngx_stream_upstream_get_hash_peer;

    hcf = ngx_stream_conf_upstream_srv_conf(us,
                                            ngx_stream_upstream_hash_module);

    if (ngx_stream_complex_value(s, &hcf->key, &hp->key) != NGX_OK) {
        return NGX_ERROR;
    }

    ngx_log_debug1(NGX_LOG_DEBUG_STREAM, s->connection->log, 0,
                   "upstream hash key:\"%V\"", &hp->key);

    hp->conf = hcf;
    hp->tries = 0;
    hp->rehash = 0;
    hp->hash = 0;
    hp->get_rr_peer = ngx_stream_upstream_get_round_robin_peer;

    return NGX_OK;
}


static ngx_int_t
ngx_stream_upstream_get_hash_peer(ngx_peer_connection_t *pc, void *data)
{
    ngx_stream_upstream_hash_peer_data_t *hp = data;

    time_t                          now;
    u_char                          buf[NGX_INT_T_LEN];
    size_t                          size;
    uint32_t                        hash;
    ngx_int_t                       w;
    uintptr_t                       m;
    ngx_uint_t                      n, p;
    ngx_stream_upstream_rr_peer_t  *peer;

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

    ngx_stream_upstream_rr_peers_rlock(hp->rrp.peers);

    if (hp->tries > 20 || hp->rrp.peers->single) {
        ngx_stream_upstream_rr_peers_unlock(hp->rrp.peers);
        return hp->get_rr_peer(pc, &hp->rrp);
    }

    now = ngx_time();

    pc->connection = NULL;

    for ( ;; ) {

        /*
         * Hash expression is compatible with Cache::Memcached:
         * ((crc32([REHASH] KEY) >> 16) & 0x7fff) + PREV_HASH
         * with REHASH omitted at the first iteration.
         */

        ngx_crc32_init(hash);

        if (hp->rehash > 0) {
            size = ngx_sprintf(buf, "%ui", hp->rehash) - buf;
            ngx_crc32_update(&hash, buf, size);
        }

        ngx_crc32_update(&hash, hp->key.data, hp->key.len);
        ngx_crc32_final(hash);

        hash = (hash >> 16) & 0x7fff;

        hp->hash += hash;
        hp->rehash++;

        w = hp->hash % hp->rrp.peers->total_weight;
        peer = hp->rrp.peers->peer;
        p = 0;

        while (w >= peer->weight) {
            w -= peer->weight;
            peer = peer->next;
            p++;
        }

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

        if (hp->rrp.tried[n] & m) {
            goto next;
        }

        ngx_stream_upstream_rr_peer_lock(hp->rrp.peers, peer);

        ngx_log_debug2(NGX_LOG_DEBUG_STREAM, pc->log, 0,
                       "get hash peer, value:%uD, peer:%ui", hp->hash, p);

        if (peer->down) {
            ngx_stream_upstream_rr_peer_unlock(hp->rrp.peers, peer);
            goto next;
        }

        if (peer->max_fails
            && peer->fails >= peer->max_fails
            && now - peer->checked <= peer->fail_timeout)
        {
            ngx_stream_upstream_rr_peer_unlock(hp->rrp.peers, peer);
            goto next;
        }

        if (peer->max_conns && peer->conns >= peer->max_conns) {
            ngx_stream_upstream_rr_peer_unlock(hp->rrp.peers, peer);
            goto next;
        }

        break;

    next:

        if (++hp->tries > 20) {
            ngx_stream_upstream_rr_peers_unlock(hp->rrp.peers);
            return hp->get_rr_peer(pc, &hp->rrp);
        }
    }

    hp->rrp.current = peer;

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

    peer->conns++;

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

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

    hp->rrp.tried[n] |= m;

    return NGX_OK;
}


static ngx_int_t
ngx_stream_upstream_init_chash(ngx_conf_t *cf,
    ngx_stream_upstream_srv_conf_t *us)
{
    u_char                               *host, *port, c;
    size_t                                host_len, port_len, size;
    uint32_t                              hash, base_hash;
    ngx_str_t                            *server;
    ngx_uint_t                            npoints, i, j;
    ngx_stream_upstream_rr_peer_t        *peer;
    ngx_stream_upstream_rr_peers_t       *peers;
    ngx_stream_upstream_chash_points_t   *points;
    ngx_stream_upstream_hash_srv_conf_t  *hcf;
    union {
        uint32_t                          value;
        u_char                            byte[4];
    } prev_hash;

    if (ngx_stream_upstream_init_round_robin(cf, us) != NGX_OK) {
        return NGX_ERROR;
    }

    us->peer.init = ngx_stream_upstream_init_chash_peer;

    peers = us->peer.data;
    npoints = peers->total_weight * 160;

    size = sizeof(ngx_stream_upstream_chash_points_t)
           + sizeof(ngx_stream_upstream_chash_point_t) * (npoints - 1);

    points = ngx_palloc(cf->pool, size);
    if (points == NULL) {
        return NGX_ERROR;
    }

    points->number = 0;

    for (peer = peers->peer; peer; peer = peer->next) {
        server = &peer->server;

        /*
         * Hash expression is compatible with Cache::Memcached::Fast:
         * crc32(HOST \0 PORT PREV_HASH).
         */

        if (server->len >= 5
            && ngx_strncasecmp(server->data, (u_char *) "unix:", 5) == 0)
        {
            host = server->data + 5;
            host_len = server->len - 5;
            port = NULL;
            port_len = 0;
            goto done;
        }

        for (j = 0; j < server->len; j++) {
            c = server->data[server->len - j - 1];

            if (c == ':') {
                host = server->data;
                host_len = server->len - j - 1;
                port = server->data + server->len - j;
                port_len = j;
                goto done;
            }

            if (c < '0' || c > '9') {
                break;
            }
        }

        host = server->data;
        host_len = server->len;
        port = NULL;
        port_len = 0;

    done:

        ngx_crc32_init(base_hash);
        ngx_crc32_update(&base_hash, host, host_len);
        ngx_crc32_update(&base_hash, (u_char *) "", 1);
        ngx_crc32_update(&base_hash, port, port_len);

        prev_hash.value = 0;
        npoints = peer->weight * 160;

        for (j = 0; j < npoints; j++) {
            hash = base_hash;

            ngx_crc32_update(&hash, prev_hash.byte, 4);
            ngx_crc32_final(hash);

            points->point[points->number].hash = hash;
            points->point[points->number].server = server;
            points->number++;

#if (NGX_HAVE_LITTLE_ENDIAN)
            prev_hash.value = hash;
#else
            prev_hash.byte[0] = (u_char) (hash & 0xff);
            prev_hash.byte[1] = (u_char) ((hash >> 8) & 0xff);
            prev_hash.byte[2] = (u_char) ((hash >> 16) & 0xff);
            prev_hash.byte[3] = (u_char) ((hash >> 24) & 0xff);
#endif
        }
    }

    ngx_qsort(points->point,
              points->number,
              sizeof(ngx_stream_upstream_chash_point_t),
              ngx_stream_upstream_chash_cmp_points);

    for (i = 0, j = 1; j < points->number; j++) {
        if (points->point[i].hash != points->point[j].hash) {
            points->point[++i] = points->point[j];
        }
    }

    points->number = i + 1;

    hcf = ngx_stream_conf_upstream_srv_conf(us,
                                            ngx_stream_upstream_hash_module);
    hcf->points = points;

    return NGX_OK;
}


static int ngx_libc_cdecl
ngx_stream_upstream_chash_cmp_points(const void *one, const void *two)
{
    ngx_stream_upstream_chash_point_t *first =
                                     (ngx_stream_upstream_chash_point_t *) one;
    ngx_stream_upstream_chash_point_t *second =
                                     (ngx_stream_upstream_chash_point_t *) two;

    if (first->hash < second->hash) {
        return -1;

    } else if (first->hash > second->hash) {
        return 1;

    } else {
        return 0;
    }
}


static ngx_uint_t
ngx_stream_upstream_find_chash_point(ngx_stream_upstream_chash_points_t *points,
    uint32_t hash)
{
    ngx_uint_t                          i, j, k;
    ngx_stream_upstream_chash_point_t  *point;

    /* find first point >= hash */

    point = &points->point[0];

    i = 0;
    j = points->number;

    while (i < j) {
        k = (i + j) / 2;

        if (hash > point[k].hash) {
            i = k + 1;

        } else if (hash < point[k].hash) {
            j = k;

        } else {
            return k;
        }
    }

    return i;
}


static ngx_int_t
ngx_stream_upstream_init_chash_peer(ngx_stream_session_t *s,
    ngx_stream_upstream_srv_conf_t *us)
{
    uint32_t                               hash;
    ngx_stream_upstream_hash_srv_conf_t   *hcf;
    ngx_stream_upstream_hash_peer_data_t  *hp;

    if (ngx_stream_upstream_init_hash_peer(s, us) != NGX_OK) {
        return NGX_ERROR;
    }

    s->upstream->peer.get = ngx_stream_upstream_get_chash_peer;

    hp = s->upstream->peer.data;
    hcf = ngx_stream_conf_upstream_srv_conf(us,
                                            ngx_stream_upstream_hash_module);

    hash = ngx_crc32_long(hp->key.data, hp->key.len);

    ngx_stream_upstream_rr_peers_rlock(hp->rrp.peers);

    hp->hash = ngx_stream_upstream_find_chash_point(hcf->points, hash);

    ngx_stream_upstream_rr_peers_unlock(hp->rrp.peers);

    return NGX_OK;
}


static ngx_int_t
ngx_stream_upstream_get_chash_peer(ngx_peer_connection_t *pc, void *data)
{
    ngx_stream_upstream_hash_peer_data_t *hp = data;

    time_t                                now;
    intptr_t                              m;
    ngx_str_t                            *server;
    ngx_int_t                             total;
    ngx_uint_t                            i, n, best_i;
    ngx_stream_upstream_rr_peer_t        *peer, *best;
    ngx_stream_upstream_chash_point_t    *point;
    ngx_stream_upstream_chash_points_t   *points;
    ngx_stream_upstream_hash_srv_conf_t  *hcf;

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

    ngx_stream_upstream_rr_peers_wlock(hp->rrp.peers);

    if (hp->tries > 20 || hp->rrp.peers->single) {
        ngx_stream_upstream_rr_peers_unlock(hp->rrp.peers);
        return hp->get_rr_peer(pc, &hp->rrp);
    }

    pc->connection = NULL;

    now = ngx_time();
    hcf = hp->conf;

    points = hcf->points;
    point = &points->point[0];

    for ( ;; ) {
        server = point[hp->hash % points->number].server;

        ngx_log_debug2(NGX_LOG_DEBUG_STREAM, pc->log, 0,
                       "consistent hash peer:%uD, server:\"%V\"",
                       hp->hash, server);

        best = NULL;
        best_i = 0;
        total = 0;

        for (peer = hp->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 (hp->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;
            }

            if (peer->server.len != server->len
                || ngx_strncmp(peer->server.data, server->data, server->len)
                   != 0)
            {
                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;
                best_i = i;
            }
        }

        if (best) {
            best->current_weight -= total;
            break;
        }

        hp->hash++;
        hp->tries++;

        if (hp->tries > 20) {
            ngx_stream_upstream_rr_peers_unlock(hp->rrp.peers);
            return hp->get_rr_peer(pc, &hp->rrp);
        }
    }

    hp->rrp.current = best;

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

    best->conns++;

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

    ngx_stream_upstream_rr_peers_unlock(hp->rrp.peers);

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

    hp->rrp.tried[n] |= m;

    return NGX_OK;
}


static void *
ngx_stream_upstream_hash_create_conf(ngx_conf_t *cf)
{
    ngx_stream_upstream_hash_srv_conf_t  *conf;

    conf = ngx_palloc(cf->pool, sizeof(ngx_stream_upstream_hash_srv_conf_t));
    if (conf == NULL) {
        return NULL;
    }

    conf->points = NULL;

    return conf;
}


static char *
ngx_stream_upstream_hash(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_stream_upstream_hash_srv_conf_t  *hcf = conf;

    ngx_str_t                           *value;
    ngx_stream_upstream_srv_conf_t      *uscf;
    ngx_stream_compile_complex_value_t   ccv;

    value = cf->args->elts;

    ngx_memzero(&ccv, sizeof(ngx_stream_compile_complex_value_t));

    ccv.cf = cf;
    ccv.value = &value[1];
    ccv.complex_value = &hcf->key;

    if (ngx_stream_compile_complex_value(&ccv) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    uscf = ngx_stream_conf_get_module_srv_conf(cf, ngx_stream_upstream_module);

    if (uscf->peer.init_upstream) {
        ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
                           "load balancing method redefined");
    }

    uscf->flags = NGX_STREAM_UPSTREAM_CREATE
                  |NGX_STREAM_UPSTREAM_WEIGHT
                  |NGX_STREAM_UPSTREAM_MAX_CONNS
                  |NGX_STREAM_UPSTREAM_MAX_FAILS
                  |NGX_STREAM_UPSTREAM_FAIL_TIMEOUT
                  |NGX_STREAM_UPSTREAM_DOWN;

    if (cf->args->nelts == 2) {
        uscf->peer.init_upstream = ngx_stream_upstream_init_hash;

    } else if (ngx_strcmp(value[2].data, "consistent") == 0) {
        uscf->peer.init_upstream = ngx_stream_upstream_init_chash;

    } else {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "invalid parameter \"%V\"", &value[2]);
        return NGX_CONF_ERROR;
    }

    return NGX_CONF_OK;
}