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view src/http/modules/ngx_http_ssl_module.c @ 4207:4fc91bae6f83

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Better recheck of dead upstream servers. Previously nginx used to mark backend again as live as soon as fail_timeout passes (10s by default) since last failure. On the other hand, detecting dead backend takes up to 60s (proxy_connect_timeout) in typical situation "backend is down and doesn't respond to any packets". This resulted in suboptimal behaviour in the above situation (up to 23% of requests were directed to dead backend with default settings). More detailed description of the problem may be found here (in Russian): http://mailman.nginx.org/pipermail/nginx-ru/2011-August/042172.html Fix is to only allow one request after fail_timeout passes, and mark backend as "live" only if this request succeeds. Note that with new code backend will not be marked "live" unless "check" request is completed, and this may take a while in some specific workloads (e.g. streaming). This is believed to be acceptable.
author Maxim Dounin <mdounin@mdounin.ru>
date Wed, 12 Oct 2011 14:22:48 +0000
parents 7de74ed694c8
children d5462eab1440
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 */


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


typedef ngx_int_t (*ngx_ssl_variable_handler_pt)(ngx_connection_t *c,
    ngx_pool_t *pool, ngx_str_t *s);


#define NGX_DEFAULT_CIPHERS     "HIGH:!aNULL:!MD5"
#define NGX_DEFAULT_ECDH_CURVE  "prime256v1"


static ngx_int_t ngx_http_ssl_static_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_ssl_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);

static ngx_int_t ngx_http_ssl_add_variables(ngx_conf_t *cf);
static void *ngx_http_ssl_create_srv_conf(ngx_conf_t *cf);
static char *ngx_http_ssl_merge_srv_conf(ngx_conf_t *cf,
    void *parent, void *child);

static char *ngx_http_ssl_enable(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static char *ngx_http_ssl_session_cache(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);


static ngx_conf_bitmask_t  ngx_http_ssl_protocols[] = {
    { ngx_string("SSLv2"), NGX_SSL_SSLv2 },
    { ngx_string("SSLv3"), NGX_SSL_SSLv3 },
    { ngx_string("TLSv1"), NGX_SSL_TLSv1 },
    { ngx_null_string, 0 }
};


static ngx_conf_enum_t  ngx_http_ssl_verify[] = {
    { ngx_string("off"), 0 },
    { ngx_string("on"), 1 },
    { ngx_string("optional"), 2 },
    { ngx_null_string, 0 }
};


static ngx_command_t  ngx_http_ssl_commands[] = {

    { ngx_string("ssl"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_FLAG,
      ngx_http_ssl_enable,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, enable),
      NULL },

    { ngx_string("ssl_certificate"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, certificate),
      NULL },

    { ngx_string("ssl_certificate_key"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, certificate_key),
      NULL },

    { ngx_string("ssl_dhparam"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, dhparam),
      NULL },

    { ngx_string("ssl_ecdh_curve"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, ecdh_curve),
      NULL },

    { ngx_string("ssl_protocols"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_1MORE,
      ngx_conf_set_bitmask_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, protocols),
      &ngx_http_ssl_protocols },

    { ngx_string("ssl_ciphers"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, ciphers),
      NULL },

    { ngx_string("ssl_verify_client"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_FLAG,
      ngx_conf_set_enum_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, verify),
      &ngx_http_ssl_verify },

    { ngx_string("ssl_verify_depth"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_1MORE,
      ngx_conf_set_num_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, verify_depth),
      NULL },

    { ngx_string("ssl_client_certificate"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, client_certificate),
      NULL },

    { ngx_string("ssl_prefer_server_ciphers"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_FLAG,
      ngx_conf_set_flag_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, prefer_server_ciphers),
      NULL },

    { ngx_string("ssl_session_cache"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE12,
      ngx_http_ssl_session_cache,
      NGX_HTTP_SRV_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("ssl_session_timeout"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_sec_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, session_timeout),
      NULL },

    { ngx_string("ssl_crl"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, crl),
      NULL },

      ngx_null_command
};


static ngx_http_module_t  ngx_http_ssl_module_ctx = {
    ngx_http_ssl_add_variables,            /* preconfiguration */
    NULL,                                  /* postconfiguration */

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

    ngx_http_ssl_create_srv_conf,          /* create server configuration */
    ngx_http_ssl_merge_srv_conf,           /* merge server configuration */

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


ngx_module_t  ngx_http_ssl_module = {
    NGX_MODULE_V1,
    &ngx_http_ssl_module_ctx,              /* module context */
    ngx_http_ssl_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
};


static ngx_http_variable_t  ngx_http_ssl_vars[] = {

    { ngx_string("ssl_protocol"), NULL, ngx_http_ssl_static_variable,
      (uintptr_t) ngx_ssl_get_protocol, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_cipher"), NULL, ngx_http_ssl_static_variable,
      (uintptr_t) ngx_ssl_get_cipher_name, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_session_id"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_session_id, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_client_cert"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_certificate, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_client_raw_cert"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_raw_certificate,
      NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_client_s_dn"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_subject_dn, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_client_i_dn"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_issuer_dn, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_client_serial"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_serial_number, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_client_verify"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_client_verify, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_null_string, NULL, NULL, 0, 0, 0 }
};


static ngx_str_t ngx_http_ssl_sess_id_ctx = ngx_string("HTTP");


static ngx_int_t
ngx_http_ssl_static_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data)
{
    ngx_ssl_variable_handler_pt  handler = (ngx_ssl_variable_handler_pt) data;

    size_t     len;
    ngx_str_t  s;

    if (r->connection->ssl) {

        (void) handler(r->connection, NULL, &s);

        v->data = s.data;

        for (len = 0; v->data[len]; len++) { /* void */ }

        v->len = len;
        v->valid = 1;
        v->no_cacheable = 0;
        v->not_found = 0;

        return NGX_OK;
    }

    v->not_found = 1;

    return NGX_OK;
}


static ngx_int_t
ngx_http_ssl_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v,
    uintptr_t data)
{
    ngx_ssl_variable_handler_pt  handler = (ngx_ssl_variable_handler_pt) data;

    ngx_str_t  s;

    if (r->connection->ssl) {

        if (handler(r->connection, r->pool, &s) != NGX_OK) {
            return NGX_ERROR;
        }

        v->len = s.len;
        v->data = s.data;

        if (v->len) {
            v->valid = 1;
            v->no_cacheable = 0;
            v->not_found = 0;

            return NGX_OK;
        }
    }

    v->not_found = 1;

    return NGX_OK;
}


static ngx_int_t
ngx_http_ssl_add_variables(ngx_conf_t *cf)
{
    ngx_http_variable_t  *var, *v;

    for (v = ngx_http_ssl_vars; v->name.len; v++) {
        var = ngx_http_add_variable(cf, &v->name, v->flags);
        if (var == NULL) {
            return NGX_ERROR;
        }

        var->get_handler = v->get_handler;
        var->data = v->data;
    }

    return NGX_OK;
}


static void *
ngx_http_ssl_create_srv_conf(ngx_conf_t *cf)
{
    ngx_http_ssl_srv_conf_t  *sscf;

    sscf = ngx_pcalloc(cf->pool, sizeof(ngx_http_ssl_srv_conf_t));
    if (sscf == NULL) {
        return NULL;
    }

    /*
     * set by ngx_pcalloc():
     *
     *     sscf->protocols = 0;
     *     sscf->certificate = { 0, NULL };
     *     sscf->certificate_key = { 0, NULL };
     *     sscf->dhparam = { 0, NULL };
     *     sscf->ecdh_curve = { 0, NULL };
     *     sscf->client_certificate = { 0, NULL };
     *     sscf->crl = { 0, NULL };
     *     sscf->ciphers = { 0, NULL };
     *     sscf->shm_zone = NULL;
     */

    sscf->enable = NGX_CONF_UNSET;
    sscf->prefer_server_ciphers = NGX_CONF_UNSET;
    sscf->verify = NGX_CONF_UNSET_UINT;
    sscf->verify_depth = NGX_CONF_UNSET_UINT;
    sscf->builtin_session_cache = NGX_CONF_UNSET;
    sscf->session_timeout = NGX_CONF_UNSET;

    return sscf;
}


static char *
ngx_http_ssl_merge_srv_conf(ngx_conf_t *cf, void *parent, void *child)
{
    ngx_http_ssl_srv_conf_t *prev = parent;
    ngx_http_ssl_srv_conf_t *conf = child;

    ngx_pool_cleanup_t  *cln;

    ngx_conf_merge_value(conf->enable, prev->enable, 0);

    ngx_conf_merge_value(conf->session_timeout,
                         prev->session_timeout, 300);

    ngx_conf_merge_value(conf->prefer_server_ciphers,
                         prev->prefer_server_ciphers, 0);

    ngx_conf_merge_bitmask_value(conf->protocols, prev->protocols,
                         (NGX_CONF_BITMASK_SET|NGX_SSL_SSLv3|NGX_SSL_TLSv1));

    ngx_conf_merge_uint_value(conf->verify, prev->verify, 0);
    ngx_conf_merge_uint_value(conf->verify_depth, prev->verify_depth, 1);

    ngx_conf_merge_str_value(conf->certificate, prev->certificate, "");
    ngx_conf_merge_str_value(conf->certificate_key, prev->certificate_key, "");

    ngx_conf_merge_str_value(conf->dhparam, prev->dhparam, "");

    ngx_conf_merge_str_value(conf->client_certificate, prev->client_certificate,
                         "");
    ngx_conf_merge_str_value(conf->crl, prev->crl, "");

    ngx_conf_merge_str_value(conf->ecdh_curve, prev->ecdh_curve,
                         NGX_DEFAULT_ECDH_CURVE);

    ngx_conf_merge_str_value(conf->ciphers, prev->ciphers, NGX_DEFAULT_CIPHERS);


    conf->ssl.log = cf->log;

    if (conf->enable) {

        if (conf->certificate.len == 0) {
            ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                          "no \"ssl_certificate\" is defined for "
                          "the \"ssl\" directive in %s:%ui",
                          conf->file, conf->line);
            return NGX_CONF_ERROR;
        }

        if (conf->certificate_key.len == 0) {
            ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                          "no \"ssl_certificate_key\" is defined for "
                          "the \"ssl\" directive in %s:%ui",
                          conf->file, conf->line);
            return NGX_CONF_ERROR;
        }

    } else {

        if (conf->certificate.len == 0) {
            return NGX_CONF_OK;
        }

        if (conf->certificate_key.len == 0) {
            ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                          "no \"ssl_certificate_key\" is defined "
                          "for certificate \"%V\"", &conf->certificate);
            return NGX_CONF_ERROR;
        }
    }

    if (ngx_ssl_create(&conf->ssl, conf->protocols, conf) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

#ifdef SSL_CTRL_SET_TLSEXT_HOSTNAME

    if (SSL_CTX_set_tlsext_servername_callback(conf->ssl.ctx,
                                               ngx_http_ssl_servername)
        == 0)
    {
        ngx_log_error(NGX_LOG_WARN, cf->log, 0,
            "nginx was built with SNI support, however, now it is linked "
            "dynamically to an OpenSSL library which has no tlsext support, "
            "therefore SNI is not available");
    }

#endif

    cln = ngx_pool_cleanup_add(cf->pool, 0);
    if (cln == NULL) {
        return NGX_CONF_ERROR;
    }

    cln->handler = ngx_ssl_cleanup_ctx;
    cln->data = &conf->ssl;

    if (ngx_ssl_certificate(cf, &conf->ssl, &conf->certificate,
                            &conf->certificate_key)
        != NGX_OK)
    {
        return NGX_CONF_ERROR;
    }

    if (SSL_CTX_set_cipher_list(conf->ssl.ctx,
                                (const char *) conf->ciphers.data)
        == 0)
    {
        ngx_ssl_error(NGX_LOG_EMERG, cf->log, 0,
                      "SSL_CTX_set_cipher_list(\"%V\") failed",
                      &conf->ciphers);
    }

    if (conf->verify) {

        if (conf->client_certificate.len == 0) {
            ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                          "no ssl_client_certificate for ssl_client_verify");
            return NGX_CONF_ERROR;
        }

        if (ngx_ssl_client_certificate(cf, &conf->ssl,
                                       &conf->client_certificate,
                                       conf->verify_depth)
            != NGX_OK)
        {
            return NGX_CONF_ERROR;
        }

        if (ngx_ssl_crl(cf, &conf->ssl, &conf->crl) != NGX_OK) {
            return NGX_CONF_ERROR;
        }
    }

    if (conf->prefer_server_ciphers) {
        SSL_CTX_set_options(conf->ssl.ctx, SSL_OP_CIPHER_SERVER_PREFERENCE);
    }

    /* a temporary 512-bit RSA key is required for export versions of MSIE */
    SSL_CTX_set_tmp_rsa_callback(conf->ssl.ctx, ngx_ssl_rsa512_key_callback);

    if (ngx_ssl_dhparam(cf, &conf->ssl, &conf->dhparam) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    if (ngx_ssl_ecdh_curve(cf, &conf->ssl, &conf->ecdh_curve) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    ngx_conf_merge_value(conf->builtin_session_cache,
                         prev->builtin_session_cache, NGX_SSL_NONE_SCACHE);

    if (conf->shm_zone == NULL) {
        conf->shm_zone = prev->shm_zone;
    }

    if (ngx_ssl_session_cache(&conf->ssl, &ngx_http_ssl_sess_id_ctx,
                              conf->builtin_session_cache,
                              conf->shm_zone, conf->session_timeout)
        != NGX_OK)
    {
        return NGX_CONF_ERROR;
    }

    return NGX_CONF_OK;
}


static char *
ngx_http_ssl_enable(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_ssl_srv_conf_t *sscf = conf;

    char  *rv;

    rv = ngx_conf_set_flag_slot(cf, cmd, conf);

    if (rv != NGX_CONF_OK) {
        return rv;
    }

    sscf->file = cf->conf_file->file.name.data;
    sscf->line = cf->conf_file->line;

    return NGX_CONF_OK;
}


static char *
ngx_http_ssl_session_cache(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_ssl_srv_conf_t *sscf = conf;

    size_t       len;
    ngx_str_t   *value, name, size;
    ngx_int_t    n;
    ngx_uint_t   i, j;

    value = cf->args->elts;

    for (i = 1; i < cf->args->nelts; i++) {

        if (ngx_strcmp(value[i].data, "off") == 0) {
            sscf->builtin_session_cache = NGX_SSL_NO_SCACHE;
            continue;
        }

        if (ngx_strcmp(value[i].data, "none") == 0) {
            sscf->builtin_session_cache = NGX_SSL_NONE_SCACHE;
            continue;
        }

        if (ngx_strcmp(value[i].data, "builtin") == 0) {
            sscf->builtin_session_cache = NGX_SSL_DFLT_BUILTIN_SCACHE;
            continue;
        }

        if (value[i].len > sizeof("builtin:") - 1
            && ngx_strncmp(value[i].data, "builtin:", sizeof("builtin:") - 1)
               == 0)
        {
            n = ngx_atoi(value[i].data + sizeof("builtin:") - 1,
                         value[i].len - (sizeof("builtin:") - 1));

            if (n == NGX_ERROR) {
                goto invalid;
            }

            sscf->builtin_session_cache = n;

            continue;
        }

        if (value[i].len > sizeof("shared:") - 1
            && ngx_strncmp(value[i].data, "shared:", sizeof("shared:") - 1)
               == 0)
        {
            len = 0;

            for (j = sizeof("shared:") - 1; j < value[i].len; j++) {
                if (value[i].data[j] == ':') {
                    value[i].data[j] = '\0';
                    break;
                }

                len++;
            }

            if (len == 0) {
                goto invalid;
            }

            name.len = len;
            name.data = value[i].data + sizeof("shared:") - 1;

            size.len = value[i].len - j - 1;
            size.data = name.data + len + 1;

            n = ngx_parse_size(&size);

            if (n == NGX_ERROR) {
                goto invalid;
            }

            if (n < (ngx_int_t) (8 * ngx_pagesize)) {
                ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                   "session cache \"%V\" is too small",
                                   &value[i]);

                return NGX_CONF_ERROR;
            }

            sscf->shm_zone = ngx_shared_memory_add(cf, &name, n,
                                                   &ngx_http_ssl_module);
            if (sscf->shm_zone == NULL) {
                return NGX_CONF_ERROR;
            }

            sscf->shm_zone->init = ngx_ssl_session_cache_init;

            continue;
        }

        goto invalid;
    }

    if (sscf->shm_zone && sscf->builtin_session_cache == NGX_CONF_UNSET) {
        sscf->builtin_session_cache = NGX_SSL_NO_BUILTIN_SCACHE;
    }

    return NGX_CONF_OK;

invalid:

    ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                       "invalid session cache \"%V\"", &value[i]);

    return NGX_CONF_ERROR;
}