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1 | /* | |
2 | * Copyright 2018 Rubén Beltrán del Río | |
3 | * | |
4 | * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the | |
5 | * License. You may obtain a copy of the License at | |
6 | * | |
7 | * http://www.apache.org/licenses/LICENSE-2.0 | |
8 | * | |
9 | * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an | |
10 | * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the | |
11 | * specific language governing permissions and limitations under the License. | |
12 | */ | |
13 | ||
14 | ||
15 | #include <ngx_config.h> | |
16 | #include <ngx_core.h> | |
17 | #include <ngx_http.h> | |
18 | ||
19 | /* | |
20 | * Declarations | |
21 | */ | |
22 | ||
23 | /* Constants */ | |
24 | ||
25 | const ngx_uint_t WEEK_LENGTH = 7; | |
26 | const char * CLOSED_TOKEN = "closed"; | |
27 | const ngx_str_t TIME_REGEX = ngx_string("([0-9]{1,2})(?:\\:([0-9]{2}))?\\-([0-9]{1,2})(?:\\:([0-9]{2}))?"); | |
28 | ||
29 | /* Main Configuration Structure */ | |
30 | ||
31 | typedef struct { | |
32 | ngx_array_t *office_hours; | |
33 | } ngx_http_office_hours_conf_t; | |
34 | ||
35 | /* Lifecycle Functions For Module Context */ | |
36 | ||
37 | static void *ngx_http_office_hours_create_conf(ngx_conf_t * cf); | |
38 | static char *ngx_http_office_hours_merge_conf(ngx_conf_t * cf, | |
39 | void *parent, void *child); | |
40 | static ngx_int_t ngx_http_office_hours_init(ngx_conf_t * cf); | |
41 | ||
42 | /* Configuration Handler */ | |
43 | ||
44 | static char *ngx_http_office_hours(ngx_conf_t * cf, ngx_command_t * cmd, | |
45 | void *conf); | |
46 | ||
47 | /* Body Filter Storage */ | |
48 | ||
49 | static ngx_http_output_body_filter_pt ngx_http_next_body_filter; | |
50 | ||
51 | /* Utility Functions */ | |
52 | static ngx_uint_t ** parse_office_hours(ngx_array_t * office_hours); | |
53 | static ngx_uint_t * parse_office_hours_string(ngx_str_t office_hours); | |
54 | static ngx_flag_t within_office_hours(ngx_uint_t ** office_hours); | |
55 | static ngx_uint_t get_day_of_week(time_t time); | |
56 | static ngx_uint_t get_seconds_of_day(time_t time); | |
57 | static ngx_uint_t parse_number(ngx_str_t string, ngx_uint_t start, ngx_uint_t end); | |
58 | ||
59 | /* Compiled Regex */ | |
60 | ngx_regex_compile_t rc; | |
61 | ||
62 | /* | |
63 | * Module Definitions | |
64 | */ | |
65 | ||
66 | /* Module Directives */ | |
67 | ||
68 | static ngx_command_t ngx_http_office_hours_commands[] = { | |
69 | { | |
70 | ngx_string("office_hours"), | |
71 | NGX_HTTP_MAIN_CONF | NGX_HTTP_SRV_CONF | NGX_HTTP_LOC_CONF | NGX_CONF_TAKE1 | NGX_CONF_TAKE2 | NGX_CONF_TAKE3 | NGX_CONF_TAKE4 | NGX_CONF_TAKE5 | NGX_CONF_TAKE6 | NGX_CONF_TAKE7, | |
72 | ngx_http_office_hours, | |
73 | NGX_HTTP_LOC_CONF_OFFSET, | |
74 | offsetof(ngx_http_office_hours_conf_t, office_hours), | |
75 | NULL | |
76 | }, | |
77 | ||
78 | ngx_null_command | |
79 | }; | |
80 | ||
81 | ||
82 | /* Module Context */ | |
83 | ||
84 | static ngx_http_module_t ngx_http_office_hours_filter_module_ctx = { | |
85 | NULL, /* Preconfiguration */ | |
86 | ngx_http_office_hours_init, /* Postconfiguration */ | |
87 | ||
88 | NULL, /* Create main configuration */ | |
89 | NULL, /* Initialize main configuration */ | |
90 | ||
91 | NULL, /* Create server configuration */ | |
92 | NULL, /* Merge server configuration */ | |
93 | ||
94 | ngx_http_office_hours_create_conf, /* Create location configuration */ | |
95 | ngx_http_office_hours_merge_conf /* Merge location configuration */ | |
96 | }; | |
97 | ||
98 | ||
99 | /* Module Definition */ | |
100 | ||
101 | ngx_module_t ngx_http_office_hours_filter_module = { | |
102 | NGX_MODULE_V1, //Module Version | |
103 | &ngx_http_office_hours_filter_module_ctx, //Module context | |
104 | ngx_http_office_hours_commands, //Module commands | |
105 | NGX_HTTP_MODULE, //Module Type | |
106 | NULL, //Initialize Master | |
107 | NULL, //Initialize Module | |
108 | NULL, //Initialize Process | |
109 | NULL, //Initialize Thread | |
110 | NULL, //Exit Thread | |
111 | NULL, //Exit Process | |
112 | NULL, //Exit Master | |
113 | NGX_MODULE_V1_PADDING | |
114 | }; | |
115 | ||
116 | ||
117 | /* | |
118 | * Main Body Filter | |
119 | * If the current time is within office hours, it goes to the next | |
120 | * handler. Otherwise it returns 403 and the office hour listing. | |
121 | */ | |
122 | ||
123 | static ngx_int_t | |
124 | ngx_http_office_hours_body_filter(ngx_http_request_t * r, ngx_chain_t * in) | |
125 | { | |
126 | ||
127 | ngx_uint_t ** parsed_office_hours; | |
128 | ngx_http_office_hours_conf_t *conf; | |
129 | ||
130 | conf = | |
131 | ngx_http_get_module_loc_conf(r, | |
132 | ngx_http_office_hours_filter_module); | |
133 | ||
134 | ||
135 | if (conf->office_hours == NULL) { | |
136 | ngx_log_error(NGX_LOG_DEBUG, r->connection->log, 0, | |
137 | "Office hours disabled"); | |
138 | return ngx_http_next_body_filter(r, in); | |
139 | } | |
140 | ||
141 | parsed_office_hours = parse_office_hours(conf->office_hours); | |
142 | ||
143 | if (within_office_hours(parsed_office_hours)) { | |
144 | ngx_log_error(NGX_LOG_DEBUG, r->connection->log, 0, | |
145 | "Within office hours"); | |
146 | return ngx_http_next_body_filter(r, in); | |
147 | } | |
148 | ||
149 | ngx_log_error(NGX_LOG_DEBUG, r->connection->log, 0, | |
150 | "Outside office hours"); | |
151 | ||
152 | r->keepalive = 0; | |
153 | return NGX_HTTP_FORBIDDEN; | |
154 | } | |
155 | ||
156 | /* | |
157 | * Callback for `office_hours ` directive | |
158 | * Reads the configuration loaded from the config file(cf) | |
159 | * And writes it to the right place in the module configuration(conf) | |
160 | */ | |
161 | ||
162 | static char *ngx_http_office_hours(ngx_conf_t * cf, ngx_command_t * cmd, | |
163 | void *conf) | |
164 | { | |
165 | ||
166 | char *conf_structure = conf; | |
167 | ||
168 | ngx_str_t *hours, *value; | |
169 | ngx_array_t **office_hours; | |
170 | ngx_uint_t i; | |
171 | ||
172 | /* Gets the array from the config structure using the defined | |
173 | * offset, and if the pointer is unset it creates a new one. | |
174 | * (The first element is the directive itself, so we should be | |
175 | * offset by 1) | |
176 | */ | |
177 | office_hours = (ngx_array_t **) (conf_structure + cmd->offset); | |
178 | ||
179 | if (*office_hours == NGX_CONF_UNSET_PTR) { | |
180 | *office_hours = ngx_array_create(cf->pool, cf->args->nelts - 1, | |
181 | sizeof(ngx_str_t)); | |
182 | ||
183 | if (*office_hours == NULL) { | |
184 | return NGX_CONF_ERROR; | |
185 | } | |
186 | } | |
187 | value = cf->args->elts; | |
188 | ||
189 | for (i = 1; i < cf->args->nelts; ++i) { | |
190 | hours = ngx_array_push(*office_hours); | |
191 | if (hours == NULL) { | |
192 | return NGX_CONF_ERROR; | |
193 | } | |
194 | *hours = value[i]; | |
195 | } | |
196 | ||
197 | return NGX_CONF_OK; | |
198 | } | |
199 | ||
200 | ||
201 | /* | |
202 | * Config Creator | |
203 | * Initializes the configuration structure | |
204 | */ | |
205 | ||
206 | static void *ngx_http_office_hours_create_conf(ngx_conf_t * cf) | |
207 | { | |
208 | ||
209 | ngx_http_office_hours_conf_t *conf; | |
210 | ||
211 | conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_office_hours_conf_t)); | |
212 | ||
213 | if (conf == NULL) { | |
214 | return NULL; | |
215 | } | |
216 | conf->office_hours = NGX_CONF_UNSET_PTR; | |
217 | ||
218 | return conf; | |
219 | } | |
220 | ||
221 | /* | |
222 | * Merge Config Values | |
223 | * Sets the defaults for the configuration and merges | |
224 | * with other configurations | |
225 | */ | |
226 | ||
227 | static char *ngx_http_office_hours_merge_conf(ngx_conf_t * cf, | |
228 | void *parent, void *child) | |
229 | { | |
230 | ||
231 | ngx_http_office_hours_conf_t *prev = parent; | |
232 | ngx_http_office_hours_conf_t *conf = child; | |
233 | ||
234 | ngx_conf_merge_ptr_value(conf->office_hours, prev->office_hours, NULL); | |
235 | ||
236 | return NGX_CONF_OK; | |
237 | } | |
238 | ||
239 | /* | |
240 | * Parse the office hour strings in the configuration file | |
241 | * to fill out the hours array (in seconds) | |
242 | */ | |
243 | ||
244 | static ngx_uint_t ** parse_office_hours(ngx_array_t * office_hours) | |
245 | { | |
246 | ||
247 | ngx_str_t *hours; | |
248 | ngx_uint_t ** parsed_office_hours; | |
249 | ngx_uint_t i, j; | |
250 | ||
251 | parsed_office_hours = malloc(7 * sizeof(ngx_uint_t *)); | |
252 | ||
253 | hours = office_hours->elts; | |
254 | ||
255 | /* | |
256 | * On the configuration file, the leftmost element | |
257 | * always applies to all remaining days, all others | |
258 | * are read from right to left. So first we will apply | |
259 | * the initial override, and then iterate based on the | |
260 | * number of overrides | |
261 | */ | |
262 | ||
263 | for (i = 0; i < WEEK_LENGTH + 1 - office_hours->nelts; ++i) { | |
264 | parsed_office_hours[i] = parse_office_hours_string(hours[0]); | |
265 | } | |
266 | ||
267 | for (i = 1; i < office_hours->nelts; ++i) { | |
268 | j = WEEK_LENGTH - office_hours->nelts + i; | |
269 | parsed_office_hours[j] = parse_office_hours_string(hours[i]); | |
270 | } | |
271 | ||
272 | return parsed_office_hours; | |
273 | } | |
274 | ||
275 | /* | |
276 | * Given a time string or the closed token, return a tuple | |
277 | * of numbers representing opening and closing hours | |
278 | */ | |
279 | ||
280 | static ngx_uint_t * parse_office_hours_string(ngx_str_t office_hours) | |
281 | { | |
282 | ||
283 | int captures[(1 + 4) * 3]; | |
284 | ngx_int_t n; | |
285 | ngx_uint_t * parsed_hours; | |
286 | ||
287 | parsed_hours = malloc(2 * sizeof(ngx_uint_t)); | |
288 | ||
289 | if(ngx_strcmp(office_hours.data, CLOSED_TOKEN) == 0) { | |
290 | parsed_hours[0] = 0; | |
291 | parsed_hours[1] = 0; | |
292 | return parsed_hours; | |
293 | } | |
294 | ||
295 | n = ngx_regex_exec(rc.regex, &office_hours, captures, (1 + 4) * 3); | |
296 | ||
297 | if (n >= 0) { | |
298 | /* Opening Hours */ | |
299 | ||
300 | parsed_hours[0] = 60 * 60 * parse_number(office_hours, captures[2], captures[3]); | |
301 | parsed_hours[0] = parsed_hours[0] + 60 * parse_number(office_hours, captures[4], captures[5]); | |
302 | ||
303 | parsed_hours[1] = 60 * 60 * parse_number(office_hours, captures[6], captures[7]); | |
304 | parsed_hours[1] = parsed_hours[1] + 60 * parse_number(office_hours, captures[8], captures[9]); | |
305 | ||
306 | return parsed_hours; | |
307 | } | |
308 | ||
309 | /* Non-matching strings count as open */ | |
310 | ||
311 | parsed_hours[0] = 0; | |
312 | parsed_hours[1] = 86400; | |
313 | return parsed_hours; | |
314 | } | |
315 | ||
316 | /* | |
317 | * Given an office hours array, it returns whether or not | |
318 | * it is currently within office hours. | |
319 | */ | |
320 | ||
321 | static ngx_flag_t within_office_hours(ngx_uint_t ** office_hours) | |
322 | { | |
323 | ||
324 | time_t now; | |
325 | ngx_uint_t day_of_week, seconds_of_day; | |
326 | ngx_uint_t * current_hours; | |
327 | ||
328 | ngx_time_update(); | |
329 | now = ngx_time(); | |
330 | day_of_week = get_day_of_week(now); | |
331 | seconds_of_day = get_seconds_of_day(now); | |
332 | current_hours = office_hours[day_of_week]; | |
333 | ||
334 | return seconds_of_day >= current_hours[0] && seconds_of_day <= current_hours[1]; | |
335 | } | |
336 | ||
337 | /* | |
338 | * Calculate the day of the week given a timestamp | |
339 | */ | |
340 | static ngx_uint_t get_day_of_week(time_t time) | |
341 | { | |
342 | ||
343 | /* Epoch was thursday, so add 3 so we start on monday */ | |
344 | return (time / 86400 + 3) % 7; | |
345 | } | |
346 | ||
347 | /* | |
348 | * Calculate the number of seconds elapsed today | |
349 | */ | |
350 | static ngx_uint_t get_seconds_of_day(time_t time) | |
351 | { | |
352 | ||
353 | return time - (time / 86400) * 86400; | |
354 | } | |
355 | ||
356 | /* | |
357 | * Parses a string, returns 0 if match was not found | |
358 | */ | |
359 | static ngx_uint_t parse_number(ngx_str_t string, ngx_uint_t start, ngx_uint_t end) | |
360 | { | |
361 | ||
362 | if (end - start == 0) { | |
363 | return 0; | |
364 | } | |
365 | ||
366 | return ngx_atoi(&string.data[start], end - start); | |
367 | } | |
368 | ||
369 | /* | |
370 | * Postconfig Initialization Handler | |
371 | * Sets the request filter at the top of the chain | |
372 | */ | |
373 | ||
374 | static ngx_int_t ngx_http_office_hours_init(ngx_conf_t * cf) | |
375 | { | |
376 | ||
377 | ngx_http_next_body_filter = ngx_http_top_body_filter; | |
378 | ngx_http_top_body_filter = ngx_http_office_hours_body_filter; | |
379 | ||
380 | rc.pattern = TIME_REGEX; | |
381 | rc.pool = cf->pool; | |
382 | if (ngx_regex_compile(&rc) != NGX_OK) { | |
383 | return NGX_ERROR; | |
384 | } | |
385 | ||
386 | return NGX_OK; | |
387 | } |