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view src/http/modules/ngx_http_browser_module.c @ 8045:aa28c802409f

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Resolver: make TCP write timer event cancelable. Similar to 70e65bf8dfd7, the change is made to ensure that the ability to cancel resolver tasks is fully controlled by the caller. As mentioned in the referenced commit, it is safe to make this timer cancelable because resolve tasks can have their own timeouts that are not cancelable. The scenario where this may become a problem is a periodic background resolve task (not tied to a specific request or a client connection), which receives a response with short TTL, large enough to warrant fallback to a TCP query. With each event loop wakeup, we either have a previously set write timer instance or schedule a new one. The non-cancelable write timer can delay or block graceful shutdown of a worker even if the ngx_resolver_ctx_t->cancelable flag is set by the API user, and there are no other tasks or connections. We use the resolver API in this way to maintain the list of upstream server addresses specified with the 'resolve' parameter, and there could be third-party modules implementing similar logic.
author Aleksei Bavshin <a.bavshin@f5.com>
date Wed, 01 Jun 2022 20:17:23 -0700
parents 2a288909abc6
children
line wrap: on
line source


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


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


/*
 * The module can check browser versions conforming to the following formats:
 * X, X.X, X.X.X, and X.X.X.X.  The maximum values of each format may be
 * 4000, 4000.99, 4000.99.99, and 4000.99.99.99.
 */


#define  NGX_HTTP_MODERN_BROWSER   0
#define  NGX_HTTP_ANCIENT_BROWSER  1


typedef struct {
    u_char                      browser[12];
    size_t                      skip;
    size_t                      add;
    u_char                      name[12];
} ngx_http_modern_browser_mask_t;


typedef struct {
    ngx_uint_t                  version;
    size_t                      skip;
    size_t                      add;
    u_char                      name[12];
} ngx_http_modern_browser_t;


typedef struct {
    ngx_array_t                *modern_browsers;
    ngx_array_t                *ancient_browsers;
    ngx_http_variable_value_t  *modern_browser_value;
    ngx_http_variable_value_t  *ancient_browser_value;

    unsigned                    modern_unlisted_browsers:1;
    unsigned                    netscape4:1;
} ngx_http_browser_conf_t;


static ngx_int_t ngx_http_msie_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_browser_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);

static ngx_uint_t ngx_http_browser(ngx_http_request_t *r,
    ngx_http_browser_conf_t *cf);

static ngx_int_t ngx_http_browser_add_variables(ngx_conf_t *cf);
static void *ngx_http_browser_create_conf(ngx_conf_t *cf);
static char *ngx_http_browser_merge_conf(ngx_conf_t *cf, void *parent,
    void *child);
static int ngx_libc_cdecl ngx_http_modern_browser_sort(const void *one,
    const void *two);
static char *ngx_http_modern_browser(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static char *ngx_http_ancient_browser(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static char *ngx_http_modern_browser_value(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static char *ngx_http_ancient_browser_value(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);


static ngx_command_t  ngx_http_browser_commands[] = {

    { ngx_string("modern_browser"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE12,
      ngx_http_modern_browser,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("ancient_browser"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
      ngx_http_ancient_browser,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("modern_browser_value"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_http_modern_browser_value,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("ancient_browser_value"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_http_ancient_browser_value,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

      ngx_null_command
};


static ngx_http_module_t  ngx_http_browser_module_ctx = {
    ngx_http_browser_add_variables,        /* preconfiguration */
    NULL,                                  /* postconfiguration */

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

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

    ngx_http_browser_create_conf,          /* create location configuration */
    ngx_http_browser_merge_conf            /* merge location configuration */
};


ngx_module_t  ngx_http_browser_module = {
    NGX_MODULE_V1,
    &ngx_http_browser_module_ctx,          /* module context */
    ngx_http_browser_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_modern_browser_mask_t  ngx_http_modern_browser_masks[] = {

    /* Opera must be the first browser to check */

    /*
     * "Opera/7.50 (X11; FreeBSD i386; U)  [en]"
     * "Mozilla/5.0 (X11; FreeBSD i386; U) Opera 7.50  [en]"
     * "Mozilla/4.0 (compatible; MSIE 6.0; X11; FreeBSD i386) Opera 7.50  [en]"
     * "Opera/8.0 (Windows NT 5.1; U; ru)"
     * "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; en) Opera 8.0"
     * "Opera/9.01 (X11; FreeBSD 6 i386; U; en)"
     */

    { "opera",
      0,
      sizeof("Opera ") - 1,
      "Opera"},

    /* "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)" */

    { "msie",
      sizeof("Mozilla/4.0 (compatible; ") - 1,
      sizeof("MSIE ") - 1,
      "MSIE "},

    /*
     * "Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.0) Gecko/20020610"
     * "Mozilla/5.0 (Windows; U; Windows NT 5.1; ru-RU; rv:1.5) Gecko/20031006"
     * "Mozilla/5.0 (Windows; U; Windows NT 5.1; ru-RU; rv:1.6) Gecko/20040206
     *              Firefox/0.8"
     * "Mozilla/5.0 (Windows; U; Windows NT 5.1; ru-RU; rv:1.7.8)
     *              Gecko/20050511 Firefox/1.0.4"
     * "Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.8.0.5) Gecko/20060729
     *              Firefox/1.5.0.5"
     */

    { "gecko",
      sizeof("Mozilla/5.0 (") - 1,
      sizeof("rv:") - 1,
      "rv:"},

    /*
     * "Mozilla/5.0 (Macintosh; U; PPC Mac OS X; ru-ru) AppleWebKit/125.2
     *              (KHTML, like Gecko) Safari/125.7"
     * "Mozilla/5.0 (SymbianOS/9.1; U; en-us) AppleWebKit/413
     *              (KHTML, like Gecko) Safari/413"
     * "Mozilla/5.0 (Macintosh; U; PPC Mac OS X; en) AppleWebKit/418
     *              (KHTML, like Gecko) Safari/417.9.3"
     * "Mozilla/5.0 (Macintosh; U; PPC Mac OS X; ru-ru) AppleWebKit/418.8
     *              (KHTML, like Gecko) Safari/419.3"
     */

    { "safari",
      sizeof("Mozilla/5.0 (") - 1,
      sizeof("Safari/") - 1,
      "Safari/"},

    /*
     * "Mozilla/5.0 (compatible; Konqueror/3.1; Linux)"
     * "Mozilla/5.0 (compatible; Konqueror/3.4; Linux) KHTML/3.4.2 (like Gecko)"
     * "Mozilla/5.0 (compatible; Konqueror/3.5; FreeBSD) KHTML/3.5.1
     *              (like Gecko)"
     */

    { "konqueror",
      sizeof("Mozilla/5.0 (compatible; ") - 1,
      sizeof("Konqueror/") - 1,
      "Konqueror/"},

    { "", 0, 0, "" }

};


static ngx_http_variable_t  ngx_http_browser_vars[] = {

    { ngx_string("msie"), NULL, ngx_http_msie_variable,
      0, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("modern_browser"), NULL, ngx_http_browser_variable,
      NGX_HTTP_MODERN_BROWSER, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ancient_browser"), NULL, ngx_http_browser_variable,
      NGX_HTTP_ANCIENT_BROWSER, NGX_HTTP_VAR_CHANGEABLE, 0 },

      ngx_http_null_variable
};


static ngx_int_t
ngx_http_browser_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v,
    uintptr_t data)
{
    ngx_uint_t                rc;
    ngx_http_browser_conf_t  *cf;

    cf = ngx_http_get_module_loc_conf(r, ngx_http_browser_module);

    rc = ngx_http_browser(r, cf);

    if (data == NGX_HTTP_MODERN_BROWSER && rc == NGX_HTTP_MODERN_BROWSER) {
        *v = *cf->modern_browser_value;
        return NGX_OK;
    }

    if (data == NGX_HTTP_ANCIENT_BROWSER && rc == NGX_HTTP_ANCIENT_BROWSER) {
        *v = *cf->ancient_browser_value;
        return NGX_OK;
    }

    *v = ngx_http_variable_null_value;
    return NGX_OK;
}


static ngx_uint_t
ngx_http_browser(ngx_http_request_t *r, ngx_http_browser_conf_t *cf)
{
    size_t                      len;
    u_char                     *name, *ua, *last, c;
    ngx_str_t                  *ancient;
    ngx_uint_t                  i, version, ver, scale;
    ngx_http_modern_browser_t  *modern;

    if (r->headers_in.user_agent == NULL) {
        if (cf->modern_unlisted_browsers) {
            return NGX_HTTP_MODERN_BROWSER;
        }

        return NGX_HTTP_ANCIENT_BROWSER;
    }

    ua = r->headers_in.user_agent->value.data;
    len = r->headers_in.user_agent->value.len;
    last = ua + len;

    if (cf->modern_browsers) {
        modern = cf->modern_browsers->elts;

        for (i = 0; i < cf->modern_browsers->nelts; i++) {
            name = ua + modern[i].skip;

            if (name >= last) {
                continue;
            }

            name = (u_char *) ngx_strstr(name, modern[i].name);

            if (name == NULL) {
                continue;
            }

            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "browser: \"%s\"", name);

            name += modern[i].add;

            if (name >= last) {
                continue;
            }

            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "version: \"%ui\" \"%s\"", modern[i].version, name);

            version = 0;
            ver = 0;
            scale = 1000000;

            while (name < last) {

                c = *name++;

                if (c >= '0' && c <= '9') {
                    ver = ver * 10 + (c - '0');
                    continue;
                }

                if (c == '.') {
                    version += ver * scale;

                    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                                   "version: \"%ui\" \"%ui\"",
                                   modern[i].version, version);

                    if (version > modern[i].version) {
                        return NGX_HTTP_MODERN_BROWSER;
                    }

                    ver = 0;
                    scale /= 100;
                    continue;
                }

                break;
            }

            version += ver * scale;

            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "version: \"%ui\" \"%ui\"",
                           modern[i].version, version);

            if (version >= modern[i].version) {
                return NGX_HTTP_MODERN_BROWSER;
            }

            return NGX_HTTP_ANCIENT_BROWSER;
        }

        if (!cf->modern_unlisted_browsers) {
            return NGX_HTTP_ANCIENT_BROWSER;
        }
    }

    if (cf->netscape4) {
        if (len > sizeof("Mozilla/4.72 ") - 1
            && ngx_strncmp(ua, "Mozilla/", sizeof("Mozilla/") - 1) == 0
            && ua[8] > '0' && ua[8] < '5')
        {
            return NGX_HTTP_ANCIENT_BROWSER;
        }
    }

    if (cf->ancient_browsers) {
        ancient = cf->ancient_browsers->elts;

        for (i = 0; i < cf->ancient_browsers->nelts; i++) {
            if (len >= ancient[i].len
                && ngx_strstr(ua, ancient[i].data) != NULL)
            {
                return NGX_HTTP_ANCIENT_BROWSER;
            }
        }
    }

    if (cf->modern_unlisted_browsers) {
        return NGX_HTTP_MODERN_BROWSER;
    }

    return NGX_HTTP_ANCIENT_BROWSER;
}


static ngx_int_t
ngx_http_msie_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v,
    uintptr_t data)
{
    if (r->headers_in.msie) {
        *v = ngx_http_variable_true_value;
        return NGX_OK;
    }

    *v = ngx_http_variable_null_value;
    return NGX_OK;
}


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

    for (v = ngx_http_browser_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_browser_create_conf(ngx_conf_t *cf)
{
    ngx_http_browser_conf_t  *conf;

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

    /*
     * set by ngx_pcalloc():
     *
     *     conf->modern_browsers = NULL;
     *     conf->ancient_browsers = NULL;
     *     conf->modern_browser_value = NULL;
     *     conf->ancient_browser_value = NULL;
     *
     *     conf->modern_unlisted_browsers = 0;
     *     conf->netscape4 = 0;
     */

    return conf;
}


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

    ngx_uint_t                  i, n;
    ngx_http_modern_browser_t  *browsers, *opera;

    /*
     * At the merge the skip field is used to store the browser slot,
     * it will be used in sorting and then will overwritten
     * with a real skip value.  The zero value means Opera.
     */

    if (conf->modern_browsers == NULL && conf->modern_unlisted_browsers == 0) {
        conf->modern_browsers = prev->modern_browsers;
        conf->modern_unlisted_browsers = prev->modern_unlisted_browsers;

    } else if (conf->modern_browsers != NULL) {
        browsers = conf->modern_browsers->elts;

        for (i = 0; i < conf->modern_browsers->nelts; i++) {
            if (browsers[i].skip == 0) {
                goto found;
            }
        }

        /*
         * Opera may contain MSIE string, so if Opera was not enumerated
         * as modern browsers, then add it and set a unreachable version
         */

        opera = ngx_array_push(conf->modern_browsers);
        if (opera == NULL) {
            return NGX_CONF_ERROR;
        }

        opera->skip = 0;
        opera->version = 4001000000U;

        browsers = conf->modern_browsers->elts;

found:

        ngx_qsort(browsers, (size_t) conf->modern_browsers->nelts,
                  sizeof(ngx_http_modern_browser_t),
                  ngx_http_modern_browser_sort);

        for (i = 0; i < conf->modern_browsers->nelts; i++) {
             n = browsers[i].skip;

             browsers[i].skip = ngx_http_modern_browser_masks[n].skip;
             browsers[i].add = ngx_http_modern_browser_masks[n].add;
             (void) ngx_cpystrn(browsers[i].name,
                                ngx_http_modern_browser_masks[n].name, 12);
        }
    }

    if (conf->ancient_browsers == NULL && conf->netscape4 == 0) {
        conf->ancient_browsers = prev->ancient_browsers;
        conf->netscape4 = prev->netscape4;
    }

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

    if (conf->modern_browser_value == NULL) {
        conf->modern_browser_value = &ngx_http_variable_true_value;
    }

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

    if (conf->ancient_browser_value == NULL) {
        conf->ancient_browser_value = &ngx_http_variable_true_value;
    }

    return NGX_CONF_OK;
}


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

    return (first->skip - second->skip);
}


static char *
ngx_http_modern_browser(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_browser_conf_t *bcf = conf;

    u_char                           c;
    ngx_str_t                       *value;
    ngx_uint_t                       i, n, version, ver, scale;
    ngx_http_modern_browser_t       *browser;
    ngx_http_modern_browser_mask_t  *mask;

    value = cf->args->elts;

    if (cf->args->nelts == 2) {
        if (ngx_strcmp(value[1].data, "unlisted") == 0) {
            bcf->modern_unlisted_browsers = 1;
            return NGX_CONF_OK;
        }

        return NGX_CONF_ERROR;
    }

    if (bcf->modern_browsers == NULL) {
        bcf->modern_browsers = ngx_array_create(cf->pool, 5,
                                            sizeof(ngx_http_modern_browser_t));
        if (bcf->modern_browsers == NULL) {
            return NGX_CONF_ERROR;
        }
    }

    browser = ngx_array_push(bcf->modern_browsers);
    if (browser == NULL) {
        return NGX_CONF_ERROR;
    }

    mask = ngx_http_modern_browser_masks;

    for (n = 0; mask[n].browser[0] != '\0'; n++) {
        if (ngx_strcasecmp(mask[n].browser, value[1].data) == 0) {
            goto found;
        }
    }

    ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                       "unknown browser name \"%V\"", &value[1]);

    return NGX_CONF_ERROR;

found:

    /*
     * at this stage the skip field is used to store the browser slot,
     * it will be used in sorting in merge stage and then will overwritten
     * with a real value
     */

    browser->skip = n;

    version = 0;
    ver = 0;
    scale = 1000000;

    for (i = 0; i < value[2].len; i++) {

        c = value[2].data[i];

        if (c >= '0' && c <= '9') {
            ver = ver * 10 + (c - '0');
            continue;
        }

        if (c == '.') {
            version += ver * scale;
            ver = 0;
            scale /= 100;
            continue;
        }

        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "invalid browser version \"%V\"", &value[2]);

        return NGX_CONF_ERROR;
    }

    version += ver * scale;

    browser->version = version;

    return NGX_CONF_OK;
}


static char *
ngx_http_ancient_browser(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_browser_conf_t *bcf = conf;

    ngx_str_t   *value, *browser;
    ngx_uint_t   i;

    value = cf->args->elts;

    for (i = 1; i < cf->args->nelts; i++) {
        if (ngx_strcmp(value[i].data, "netscape4") == 0) {
            bcf->netscape4 = 1;
            continue;
        }

        if (bcf->ancient_browsers == NULL) {
            bcf->ancient_browsers = ngx_array_create(cf->pool, 4,
                                                     sizeof(ngx_str_t));
            if (bcf->ancient_browsers == NULL) {
                return NGX_CONF_ERROR;
            }
        }

        browser = ngx_array_push(bcf->ancient_browsers);
        if (browser == NULL) {
            return NGX_CONF_ERROR;
        }

        *browser = value[i];
    }

    return NGX_CONF_OK;
}


static char *
ngx_http_modern_browser_value(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_browser_conf_t *bcf = conf;

    ngx_str_t  *value;

    bcf->modern_browser_value = ngx_palloc(cf->pool,
                                           sizeof(ngx_http_variable_value_t));
    if (bcf->modern_browser_value == NULL) {
        return NGX_CONF_ERROR;
    }

    value = cf->args->elts;

    bcf->modern_browser_value->len = value[1].len;
    bcf->modern_browser_value->valid = 1;
    bcf->modern_browser_value->no_cacheable = 0;
    bcf->modern_browser_value->not_found = 0;
    bcf->modern_browser_value->data = value[1].data;

    return NGX_CONF_OK;
}


static char *
ngx_http_ancient_browser_value(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_browser_conf_t *bcf = conf;

    ngx_str_t  *value;

    bcf->ancient_browser_value = ngx_palloc(cf->pool,
                                            sizeof(ngx_http_variable_value_t));
    if (bcf->ancient_browser_value == NULL) {
        return NGX_CONF_ERROR;
    }

    value = cf->args->elts;

    bcf->ancient_browser_value->len = value[1].len;
    bcf->ancient_browser_value->valid = 1;
    bcf->ancient_browser_value->no_cacheable = 0;
    bcf->ancient_browser_value->not_found = 0;
    bcf->ancient_browser_value->data = value[1].data;

    return NGX_CONF_OK;
}