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