ngx_http_userid_filter_module.c

Nginx是一个高性能的HTTP和反向代理服务器

/*
 * Copyright (C) Igor Sysoev
 */


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


#define NGX_HTTP_USERID_OFF   0
#define NGX_HTTP_USERID_LOG   1
#define NGX_HTTP_USERID_V1    2
#define NGX_HTTP_USERID_ON    3

/* 31 Dec 2037 23:55:55 GMT */
#define NGX_HTTP_USERID_MAX_EXPIRES  2145916555


typedef struct {
    ngx_uint_t  enable;

    ngx_int_t   service;

    ngx_str_t   name;
    ngx_str_t   domain;
    ngx_str_t   path;
    ngx_str_t   p3p;

    time_t      expires;

    u_char      mark;
} ngx_http_userid_conf_t;


typedef struct {
    uint32_t    uid_got[4];
    uint32_t    uid_set[4];
    ngx_str_t   cookie;
} ngx_http_userid_ctx_t;


static void ngx_http_userid_get_uid(ngx_http_request_t *r,
    ngx_http_userid_ctx_t *ctx, ngx_http_userid_conf_t *conf);
static ngx_int_t ngx_http_userid_set_uid(ngx_http_request_t *r,
    ngx_http_userid_ctx_t *ctx, ngx_http_userid_conf_t *conf);

static ngx_int_t ngx_http_userid_add_variables(ngx_conf_t *cf);
static ngx_int_t ngx_http_userid_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);

static ngx_int_t ngx_http_userid_init(ngx_conf_t *cf);
static void *ngx_http_userid_create_conf(ngx_conf_t *cf);
static char *ngx_http_userid_merge_conf(ngx_conf_t *cf, void *parent,
    void *child);
static char *ngx_http_userid_domain(ngx_conf_t *cf, void *post, void *data);
static char *ngx_http_userid_path(ngx_conf_t *cf, void *post, void *data);
static char *ngx_http_userid_expires(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static char *ngx_http_userid_p3p(ngx_conf_t *cf, void *post, void *data);
static char *ngx_http_userid_mark(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static ngx_int_t ngx_http_userid_init_worker(ngx_cycle_t *cycle);



static uint32_t  start_value;
static uint32_t  sequencer_v1 = 1;
static uint32_t  sequencer_v2 = 0x03030302;


static u_char expires[] = "; expires=Thu, 31-Dec-37 23:55:55 GMT";


static ngx_http_output_header_filter_pt  ngx_http_next_header_filter;


static ngx_conf_enum_t  ngx_http_userid_state[] = {
    { ngx_string("off"), NGX_HTTP_USERID_OFF },
    { ngx_string("log"), NGX_HTTP_USERID_LOG },
    { ngx_string("v1"), NGX_HTTP_USERID_V1 },
    { ngx_string("on"), NGX_HTTP_USERID_ON },
    { ngx_null_string, 0 }
};


static ngx_conf_post_handler_pt  ngx_http_userid_domain_p =
    ngx_http_userid_domain;
static ngx_conf_post_handler_pt  ngx_http_userid_path_p = ngx_http_userid_path;
static ngx_conf_post_handler_pt  ngx_http_userid_p3p_p = ngx_http_userid_p3p;


static ngx_command_t  ngx_http_userid_commands[] = {

    { ngx_string("userid"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_enum_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_userid_conf_t, enable),
      ngx_http_userid_state },

    { ngx_string("userid_service"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_num_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_userid_conf_t, service),
      NULL },

    { ngx_string("userid_name"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_userid_conf_t, name),
      NULL },

    { ngx_string("userid_domain"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_userid_conf_t, domain),
      &ngx_http_userid_domain_p },

    { ngx_string("userid_path"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_userid_conf_t, path),
      &ngx_http_userid_path_p },

    { ngx_string("userid_expires"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_http_userid_expires,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("userid_p3p"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_userid_conf_t, p3p),
      &ngx_http_userid_p3p_p },

    { ngx_string("userid_mark"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_http_userid_mark,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

      ngx_null_command
};


static ngx_http_module_t  ngx_http_userid_filter_module_ctx = {
    ngx_http_userid_add_variables,         /* preconfiguration */
    ngx_http_userid_init,                  /* postconfiguration */

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

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

    ngx_http_userid_create_conf,           /* create location configration */
    ngx_http_userid_merge_conf             /* merge location configration */
};


ngx_module_t  ngx_http_userid_filter_module = {
    NGX_MODULE_V1,
    &ngx_http_userid_filter_module_ctx,    /* module context */
    ngx_http_userid_commands,              /* module directives */
    NGX_HTTP_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    ngx_http_userid_init_worker,           /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


static ngx_str_t  ngx_http_userid_got = ngx_string("uid_got");
static ngx_str_t  ngx_http_userid_set = ngx_string("uid_set");


static ngx_int_t
ngx_http_userid_filter(ngx_http_request_t *r)
{
    ngx_int_t                rc;
    ngx_http_userid_ctx_t   *ctx;
    ngx_http_userid_conf_t  *conf;

    if (r != r->main) {
        return ngx_http_next_header_filter(r);
    }

    conf = ngx_http_get_module_loc_conf(r, ngx_http_userid_filter_module);

    if (conf->enable == NGX_HTTP_USERID_OFF) {
        return ngx_http_next_header_filter(r);
    }


    ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_userid_ctx_t));
    if (ctx == NULL) {
        return NGX_ERROR;
    }

    ngx_http_set_ctx(r, ctx, ngx_http_userid_filter_module);

    ngx_http_userid_get_uid(r, ctx, conf);

    if (conf->enable == NGX_HTTP_USERID_LOG) {
        return ngx_http_next_header_filter(r);
    }

    if (ctx->uid_got[3] != 0) {
        if (conf->mark == '\0') {
            return ngx_http_next_header_filter(r);

        } else {
            if (ctx->cookie.len > 23
                && ctx->cookie.data[22] == conf->mark
                && ctx->cookie.data[23] == '=')
            {
                return ngx_http_next_header_filter(r);
            }
        }
    }

    rc = ngx_http_userid_set_uid(r, ctx, conf);

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

    return ngx_http_next_header_filter(r);
}


static void
ngx_http_userid_get_uid(ngx_http_request_t *r, ngx_http_userid_ctx_t *ctx,
    ngx_http_userid_conf_t *conf)
{
    ngx_int_t          n;
    ngx_str_t          src, dst;
    ngx_table_elt_t  **cookies;

    n = ngx_http_parse_multi_header_lines(&r->headers_in.cookies, &conf->name,
                                          &ctx->cookie);
    if (n == NGX_DECLINED) {
        return;
    }

    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "uid cookie: \"%V\"", &ctx->cookie);

    if (ctx->cookie.len < 22) {
        cookies = r->headers_in.cookies.elts;
        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                      "client sent too short userid cookie \"%V\"",
                      &cookies[n]->value);
        return;
    }

    src = ctx->cookie;

    /*
     * we have to limit the encoded string to 22 characters because
     *  1) cookie may be marked by "userid_mark",
     *  2) and there are already the millions cookies with a garbage
     *     instead of the correct base64 trail "=="
     */

    src.len = 22;

    dst.data = (u_char *) ctx->uid_got;

    if (ngx_decode_base64(&dst, &src) == NGX_ERROR) {
        cookies = r->headers_in.cookies.elts;
        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                      "client sent invalid userid cookie \"%V\"",
                      &cookies[n]->value);
        return;
    }

    ngx_log_debug4(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "uid: %08XD%08XD%08XD%08XD",
                   ctx->uid_got[0], ctx->uid_got[1],
                   ctx->uid_got[2], ctx->uid_got[3]);
}


static ngx_int_t
ngx_http_userid_set_uid(ngx_http_request_t *r, ngx_http_userid_ctx_t *ctx,
    ngx_http_userid_conf_t *conf)
{
    u_char           *cookie, *p;
    size_t            len;
    ngx_str_t         src, dst;
    ngx_table_elt_t  *set_cookie, *p3p;

    /*
     * TODO: in the threaded mode the sequencers should be in TLS and their
     * ranges should be divided between threads
     */

    if (ctx->uid_got[3] == 0) {

        if (conf->enable == NGX_HTTP_USERID_V1) {
            if (conf->service == NGX_CONF_UNSET) {
                ctx->uid_set[0] = 0;
            } else {
                ctx->uid_set[0] = conf->service;
            }
            ctx->uid_set[1] = (uint32_t) ngx_time();
            ctx->uid_set[2] = start_value;
            ctx->uid_set[3] = sequencer_v1;
            sequencer_v1 += 0x100;

        } else {
            if (conf->service == NGX_CONF_UNSET) {
                if (ngx_http_server_addr(r, NULL) != NGX_OK) {
                    return NGX_ERROR;
                }

                ctx->uid_set[0] = htonl(r->in_addr);

            } else {
                ctx->uid_set[0] = htonl(conf->service);
            }

            ctx->uid_set[1] = htonl((uint32_t) ngx_time());
            ctx->uid_set[2] = htonl(start_value);
            ctx->uid_set[3] = htonl(sequencer_v2);
            sequencer_v2 += 0x100;
            if (sequencer_v2 < 0x03030302) {
                sequencer_v2 = 0x03030302;
            }
        }

    } else {
        ctx->uid_set[0] = ctx->uid_got[0];
        ctx->uid_set[1] = ctx->uid_got[1];
        ctx->uid_set[2] = ctx->uid_got[2];
        ctx->uid_set[3] = ctx->uid_got[3];
    }

    len = conf->name.len + 1 + ngx_base64_encoded_length(16) + conf->path.len;

    if (conf->expires) {
        len += sizeof(expires) - 1 + 2;