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view src/http/modules/ngx_http_upstream_ip_hash_module.c @ 4247:b79dbadb3d5e stable-1.0

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Merging r4147, r4148, r4149, r4150, r4207: Fixes of combination of error_page and return directives: *) Fix for incorrect 201 replies from dav module. Replies with 201 code contain body, and we should clearly indicate it's empty if it's empty. Before 0.8.32 chunked was explicitly disabled for 201 replies and as a result empty body was indicated by connection close (not perfect, but worked). Since 0.8.32 chunked is enabled, and this causes incorrect responses from dav module when HTTP/1.1 is used: with "Transfer-Encoding: chunked" but no chunks at all. Fix is to actually return empty body in special response handler instead of abusing r->header_only flag. See here for initial report: http://mailman.nginx.org/pipermail/nginx-ru/2010-October/037535.html *) Fix for double content when return is used in error_page handler. Test case: location / { error_page 405 /nope; return 405; } location /nope { return 200; } This is expected to return 405 with empty body, but in 0.8.42+ will return builtin 405 error page as well (though not counted in Content-Length, thus breaking protocol). Fix is to use status provided by rewrite script execution in case it's less than NGX_HTTP_BAD_REQUEST even if r->error_status set. This check is in line with one in ngx_http_script_return_code(). Note that this patch also changes behaviour for "return 302 ..." and "rewrite ... redirect" used as error handler. E.g. location / { error_page 405 /redirect; return 405; } location /redirect { rewrite ^ http://example.com/; } will actually return redirect to "http://example.com/" instead of builtin 405 error page with meaningless Location header. This looks like correct change and it's in line with what happens on e.g. directory redirects in error handlers. *) Fix for "return 202" not discarding body. Big POST (not fully preread) to a location / { return 202; } resulted in incorrect behaviour due to "return" code path not calling ngx_http_discard_request_body(). The same applies to all "return" used with 2xx/3xx codes except 201 and 204, and to all "return ... text" uses. Fix is to add ngx_http_discard_request_body() call to ngx_http_send_response() function where it looks appropriate. Discard body call from emtpy gif module removed as it's now redundant. Reported by Pyry Hakulinen, see http://mailman.nginx.org/pipermail/nginx/2011-August/028503.html *) Incorrect special case for "return 204" removed. The special case in question leads to replies without body in configuration like location / { error_page 404 /zero; return 404; } location /zero { return 204; } while replies with empty body are expected per protocol specs. Correct one will look like if (status == NGX_HTTP_NO_CONTENT) { rc = ngx_http_send_header(r); if (rc == NGX_ERROR || r->header_only) { return rc; } return ngx_http_send_special(r, NGX_HTTP_LAST); } though it looks like it's better to drop this special case at all. *) Clear old Location header (if any) while adding a new one. This prevents incorrect behaviour when another redirect is issued within error_page 302 handler.
author Igor Sysoev <igor@sysoev.ru>
date Tue, 01 Nov 2011 13:45:33 +0000
parents 2e91aecb9e57
children 4fc91bae6f83 4919fb357a5d
line wrap: on
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/*
 * Copyright (C) Igor Sysoev
 */


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


typedef struct {
    /* the round robin data must be first */
    ngx_http_upstream_rr_peer_data_t   rrp;

    ngx_uint_t                         hash;

    u_char                             addr[3];

    u_char                             tries;

    ngx_event_get_peer_pt              get_rr_peer;
} ngx_http_upstream_ip_hash_peer_data_t;


static ngx_int_t ngx_http_upstream_init_ip_hash_peer(ngx_http_request_t *r,
    ngx_http_upstream_srv_conf_t *us);
static ngx_int_t ngx_http_upstream_get_ip_hash_peer(ngx_peer_connection_t *pc,
    void *data);
static char *ngx_http_upstream_ip_hash(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);


static ngx_command_t  ngx_http_upstream_ip_hash_commands[] = {

    { ngx_string("ip_hash"),
      NGX_HTTP_UPS_CONF|NGX_CONF_NOARGS,
      ngx_http_upstream_ip_hash,
      0,
      0,
      NULL },

      ngx_null_command
};


static ngx_http_module_t  ngx_http_upstream_ip_hash_module_ctx = {
    NULL,                                  /* preconfiguration */
    NULL,                                  /* postconfiguration */

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

    NULL,                                  /* create server configuration */
    NULL,                                  /* merge server configuration */

    NULL,                                  /* create location configuration */
    NULL                                   /* merge location configuration */
};


ngx_module_t  ngx_http_upstream_ip_hash_module = {
    NGX_MODULE_V1,
    &ngx_http_upstream_ip_hash_module_ctx, /* module context */
    ngx_http_upstream_ip_hash_commands,    /* module directives */
    NGX_HTTP_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
};


ngx_int_t
ngx_http_upstream_init_ip_hash(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us)
{
    if (ngx_http_upstream_init_round_robin(cf, us) != NGX_OK) {
        return NGX_ERROR;
    }

    us->peer.init = ngx_http_upstream_init_ip_hash_peer;

    return NGX_OK;
}


static ngx_int_t
ngx_http_upstream_init_ip_hash_peer(ngx_http_request_t *r,
    ngx_http_upstream_srv_conf_t *us)
{
    u_char                                 *p;
    struct sockaddr_in                     *sin;
    ngx_http_upstream_ip_hash_peer_data_t  *iphp;

    iphp = ngx_palloc(r->pool, sizeof(ngx_http_upstream_ip_hash_peer_data_t));
    if (iphp == NULL) {
        return NGX_ERROR;
    }

    r->upstream->peer.data = &iphp->rrp;

    if (ngx_http_upstream_init_round_robin_peer(r, us) != NGX_OK) {
        return NGX_ERROR;
    }

    r->upstream->peer.get = ngx_http_upstream_get_ip_hash_peer;

    /* AF_INET only */

    if (r->connection->sockaddr->sa_family == AF_INET) {

        sin = (struct sockaddr_in *) r->connection->sockaddr;
        p = (u_char *) &sin->sin_addr.s_addr;
        iphp->addr[0] = p[0];
        iphp->addr[1] = p[1];
        iphp->addr[2] = p[2];

    } else {
        iphp->addr[0] = 0;
        iphp->addr[1] = 0;
        iphp->addr[2] = 0;
    }

    iphp->hash = 89;
    iphp->tries = 0;
    iphp->get_rr_peer = ngx_http_upstream_get_round_robin_peer;

    return NGX_OK;
}


static ngx_int_t
ngx_http_upstream_get_ip_hash_peer(ngx_peer_connection_t *pc, void *data)
{
    ngx_http_upstream_ip_hash_peer_data_t  *iphp = data;

    time_t                        now;
    uintptr_t                     m;
    ngx_uint_t                    i, n, p, hash;
    ngx_http_upstream_rr_peer_t  *peer;

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

    /* TODO: cached */

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

    now = ngx_time();

    pc->cached = 0;
    pc->connection = NULL;

    hash = iphp->hash;

    for ( ;; ) {

        for (i = 0; i < 3; i++) {
            hash = (hash * 113 + iphp->addr[i]) % 6271;
        }

        p = hash % iphp->rrp.peers->number;

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

        if (!(iphp->rrp.tried[n] & m)) {

            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0,
                           "get ip hash peer, hash: %ui %04XA", p, m);

            peer = &iphp->rrp.peers->peer[p];

            /* ngx_lock_mutex(iphp->rrp.peers->mutex); */

            if (!peer->down) {

                if (peer->max_fails == 0 || peer->fails < peer->max_fails) {
                    break;
                }

                if (now - peer->accessed > peer->fail_timeout) {
                    peer->fails = 0;
                    break;
                }
            }

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

            /* ngx_unlock_mutex(iphp->rrp.peers->mutex); */

            pc->tries--;
        }

        if (++iphp->tries >= 20) {
            return iphp->get_rr_peer(pc, &iphp->rrp);
        }
    }

    iphp->rrp.current = p;

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

    /* ngx_unlock_mutex(iphp->rrp.peers->mutex); */

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

    return NGX_OK;
}


static char *
ngx_http_upstream_ip_hash(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_upstream_srv_conf_t  *uscf;

    uscf = ngx_http_conf_get_module_srv_conf(cf, ngx_http_upstream_module);

    uscf->peer.init_upstream = ngx_http_upstream_init_ip_hash;

    uscf->flags = NGX_HTTP_UPSTREAM_CREATE
                  |NGX_HTTP_UPSTREAM_MAX_FAILS
                  |NGX_HTTP_UPSTREAM_FAIL_TIMEOUT
                  |NGX_HTTP_UPSTREAM_DOWN;

    return NGX_CONF_OK;
}