1 /*
2  * Copyright (c) 2019 Martijn van Duren <martijn@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 #include <sys/time.h>
17 #include <sys/socket.h>
18 
19 #include <arpa/inet.h>
20 #include <errno.h>
21 #include <event.h>
22 #include <fcntl.h>
23 #include <inttypes.h>
24 #include <stdarg.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <string.h>
28 #include <syslog.h>
29 #include <unistd.h>
30 
31 #include "log.h"
32 #include "smtp_proc.h"
33 
34 #define NITEMS(x) (sizeof(x) / sizeof(*x))
35 
36 struct smtp_callback;
37 struct smtp_request;
38 
39 static int smtp_register(char *, char *, char *, void *);
40 static void smtp_newline(int, short, void *);
41 static void smtp_connect(struct smtp_callback *, int, struct timespec *,
42     uint64_t, uint64_t, char *);
43 static void smtp_dataline(struct smtp_callback *, int, struct timespec *,
44     uint64_t, uint64_t, char *);
45 static void smtp_in_link_disconnect(struct smtp_callback *, int, struct timespec *,
46     uint64_t, char *);
47 
48 struct smtp_callback {
49 	char *type;
50 	char *phase;
51 	char *direction;
52 	union {
53 		void (*smtp_filter)(struct smtp_callback *, int,
54 		    struct timespec *, uint64_t, uint64_t, char *);
55 		void (*smtp_report)(struct smtp_callback *, int,
56 		    struct timespec *, uint64_t, char *);
57 	};
58 	void *cb;
59 } smtp_callbacks[] = {
60         {"filter", "connect", "smtp-in", .smtp_filter = smtp_connect, NULL},
61         {"filter", "data-line", "smtp-in", .smtp_filter = smtp_dataline, NULL},
62 	{"report", "link-disconnect", "smtp-in",
63 	    .smtp_report = smtp_in_link_disconnect, NULL}
64 };
65 
66 static int ready = 0;
67 
68 int
69 smtp_register_filter_connect(void (*cb)(char *, int, struct timespec *, char *,
70     char *, uint64_t, uint64_t, char *, struct inx_addr *))
71 {
72 	return smtp_register("filter", "connect", "smtp-in", (void *)cb);
73 }
74 
75 int
76 smtp_register_filter_dataline(void (*cb)(char *, int, struct timespec *, char *,
77     char *, uint64_t, uint64_t, char *))
78 {
79 	return smtp_register("filter", "data-line", "smtp-in", (void *)cb);
80 }
81 
82 int
83 smtp_in_register_report_disconnect(void (*cb)(char *, int, struct timespec *,
84     char *, char *, uint64_t))
85 {
86 	return smtp_register("report", "link-disconnect", "smtp-in", (void *)cb);
87 }
88 
89 void
90 smtp_run(int debug)
91 {
92 	struct event stdinev;
93 
94 	printf("register|ready\n");
95 	fflush(stdout);
96 	ready = 1;
97 
98 	log_init(debug, LOG_MAIL);
99 	event_init();
100 	event_set(&stdinev, STDIN_FILENO, EV_READ | EV_PERSIST, smtp_newline,
101 	    &stdinev);
102 	event_add(&stdinev, NULL);
103 
104 	if (fcntl(STDIN_FILENO, F_SETFL, O_NONBLOCK) == -1)
105 		fatal("fcntl");
106 	event_dispatch();
107 }
108 
109 static void
110 smtp_newline(int fd, short event, void *arg)
111 {
112 	struct event *stdinev = (struct event *)arg;
113 	char *line = NULL;
114 	size_t linesize = 0;
115 	ssize_t linelen;
116 	char *start, *end, *type, *direction, *phase, *params;
117 	int version;
118 	struct timespec tm;
119 	uint64_t reqid, token;
120 	int i;
121 
122 	while ((linelen = getline(&line, &linesize, stdin)) != -1) {
123 		if (line[linelen - 1] != '\n')
124 			fatalx("Invalid line received: missing newline");
125 		line[linelen - 1] = '\0';
126 		type = line;
127 		if ((start = strchr(type, '|')) == NULL)
128 			fatalx("Invalid line received: missing version");
129 		start++[0] = '\0';
130 		if ((end = strchr(start, '|')) == NULL)
131 			fatalx("Invalid line received: missing time");
132 		end++[0] = '\0';
133 		if (strcmp(start, "1") != 0)
134 			fatalx("Unsupported protocol received: %s", start);
135 		version = 1;
136 		start = end;
137 		if ((direction = strchr(start, '|')) == NULL)
138 			fatalx("Invalid line received: missing direction");
139 		direction++[0] = '\0';
140 		tm.tv_sec = (time_t) strtoull(start, &end, 10);
141 		tm.tv_nsec = 0;
142 		if (start[0] == '\0' || (end[0] != '\0' && end[0] != '.'))
143 			fatalx("Invalid line received: invalid timestamp");
144 		if (end[0] == '.') {
145 			start = end + 1;
146 			tm.tv_nsec = strtol(start, &end, 10);
147 			if (start[0] == '\0' || end[0] != '\0')
148 				fatalx("Invalid line received: invalid "
149 				    "timestamp");
150 			for (i = 9 - (end - start); i > 0; i--)
151 				tm.tv_nsec *= 10;
152 		}
153 		if ((phase = strchr(direction, '|')) == NULL)
154 			fatalx("Invalid line receieved: missing phase");
155 		phase++[0] = '\0';
156 		if ((start = strchr(phase, '|')) == NULL)
157 			fatalx("Invalid line received: missing reqid");
158 		start++[0] = '\0';
159 		reqid = strtoull(start, &params, 16);
160 		if (start[0] == '|' || (params[0] != '|' & params[0] != '\0'))
161 			fatalx("Invalid line received: invalid reqid");
162 		params++;
163 
164 		for (i = 0; i < NITEMS(smtp_callbacks); i++) {
165 			if (strcmp(type, smtp_callbacks[i].type) == 0 &&
166 			    strcmp(phase, smtp_callbacks[i].phase) == 0 &&
167 			    strcmp(direction, smtp_callbacks[i].direction) == 0)
168 				break;
169 		}
170 		if (i == NITEMS(smtp_callbacks)) {
171 			fatalx("Invalid line received: received unregistered "
172 			    "%s: %s", type, phase);
173 		}
174 		if (strcmp(type, "filter") == 0) {
175 			start = params;
176 			token = strtoull(start, &params, 16);
177 			if (start[0] == '|' || params[0] != '|')
178 				fatalx("Invalid line received: invalid token");
179 			params++;
180 			smtp_callbacks[i].smtp_filter(&(smtp_callbacks[i]),
181 			    version, &tm, reqid, token, params);
182 		} else
183 			smtp_callbacks[i].smtp_report(&(smtp_callbacks[i]),
184 			    version, &tm, reqid, params);
185 	}
186 	if (feof(stdin) || (ferror(stdin) && errno != EAGAIN))
187 		event_del(stdinev);
188 }
189 
190 static void
191 smtp_connect(struct smtp_callback *cb, int version, struct timespec *tm,
192     uint64_t reqid, uint64_t token, char *params)
193 {
194 	struct inx_addr addrx;
195 	char *hostname;
196 	char *address;
197 	int ret;
198 	void (*f)(char *, int, struct timespec *,char *, char *, uint64_t,
199 	    uint64_t, char *, struct inx_addr *);
200 
201 	hostname = params;
202 	if ((address = strchr(params, '|')) == NULL)
203 		fatalx("Invalid line received: missing address");
204 	address++[0] = '\0';
205 
206 	addrx.af = AF_INET;
207 	if (strncasecmp(address, "ipv6:", 5) == 0) {
208 		addrx.af = AF_INET6;
209 		address += 5;
210 	}
211 
212 	ret = inet_pton(addrx.af, address, addrx.af == AF_INET ?
213 	    (void *)&(addrx.addr) : (void *)&(addrx.addr6));
214 	if (ret == 0)
215 		fatalx("Invalid line received: Couldn't parse address");
216 	if (ret == -1)
217 		fatalx("Couldn't convert address");
218 
219 	f = cb->cb;
220 	f(cb->type, version, tm, cb->direction, cb->phase, reqid, token,
221 	    hostname, &addrx);
222 }
223 
224 static void
225 smtp_dataline(struct smtp_callback *cb, int version, struct timespec *tm,
226     uint64_t reqid, uint64_t token, char *line)
227 {
228 	void (*f)(char *, int, struct timespec *,char *, char *, uint64_t,
229 	    uint64_t, char *);
230 
231 	f = cb->cb;
232 	f(cb->type, version, tm, cb->direction, cb->phase, reqid, token,
233 	    line);
234 }
235 
236 static void
237 smtp_in_link_disconnect(struct smtp_callback *cb, int version,
238     struct timespec *tm, uint64_t reqid, char *params)
239 {
240 	void (*f)(char *, int, struct timespec *, char *, char *, uint64_t);
241 
242 	f = cb->cb;
243 	f(cb->type, version, tm, cb->direction, cb->phase, reqid);
244 }
245 
246 void
247 smtp_filter_proceed(uint64_t reqid, uint64_t token)
248 {
249 	printf("filter-result|%016"PRIx64"|%016"PRIx64"|proceed\n", token,
250 	    reqid);
251 	fflush(stdout);
252 }
253 
254 void
255 smtp_filter_reject(uint64_t reqid, uint64_t token, int code,
256     const char *reason, ...)
257 {
258 	va_list ap;
259 
260 	if (code < 200 || code > 599)
261 		fatalx("Invalid reject code");
262 
263 	printf("filter-result|%016"PRIx64"|%016"PRIx64"|reject|%d ", token,
264 	    reqid, code);
265 	va_start(ap, reason);
266 	vprintf(reason, ap);
267 	va_end(ap);
268 	putchar('\n');
269 	fflush(stdout);
270 }
271 
272 void
273 smtp_filter_disconnect(uint64_t reqid, uint64_t token, const char *reason, ...)
274 {
275 	va_list ap;
276 
277 	printf("filter-result|%016"PRIx64"|%016"PRIx64"|disconnect|421 ",
278 	    token, reqid);
279 	va_start(ap, reason);
280 	vprintf(reason, ap);
281 	va_end(ap);
282 	putchar('\n');
283 	fflush(stdout);
284 }
285 
286 void
287 smtp_filter_dataline(uint64_t reqid, uint64_t token, const char *line, ...)
288 {
289 	va_list ap;
290 
291 	printf("filter-dataline|%016"PRIx64"|%016"PRIx64"|", token, reqid);
292 	va_start(ap, line);
293 	vprintf(line, ap);
294 	va_end(ap);
295 	putchar('\n');
296 	fflush(stdout);
297 }
298 
299 static int
300 smtp_register(char *type, char *phase, char *direction, void *cb)
301 {
302 	int i;
303 
304 	if (ready)
305 		fatalx("Can't register when proc is running");
306 
307 	for (i = 0; i < NITEMS(smtp_callbacks); i++) {
308 		if (strcmp(type, smtp_callbacks[i].type) == 0 &&
309 		    strcmp(phase, smtp_callbacks[i].phase) == 0 &&
310 		    strcmp(direction, smtp_callbacks[i].direction) == 0) {
311 			if (smtp_callbacks[i].cb != NULL) {
312 				errno = EALREADY;
313 				return -1;
314 			}
315 			smtp_callbacks[i].cb = cb;
316 			printf("register|%s|%s|%s\n", type, direction, phase);
317 			return 0;
318 		}
319 	}
320 	errno = EINVAL;
321 	return -1;
322 }