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Date:: Mon Jul 12 19:59:37 2021 UTC
Message:: refactor: all imsgs are completely asynchronous
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1 /*
2  * Copyright (c) 2021 Omar Polo <op@omarpolo.com>
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 
17 #include "telescope.h"
18 
19 #include <sys/types.h>
20 #include <sys/socket.h>
21 
22 #include <netinet/in.h>
23 
24 #include <assert.h>
25 #include <ctype.h>
26 #include <errno.h>
27 #include <netdb.h>
28 #include <stdarg.h>
29 #include <stdio.h>
30 #include <stdlib.h>
31 #include <string.h>
32 #include <tls.h>
33 #include <unistd.h>
34 
35 #if HAVE_ASR_RUN
36 # include <asr.h>
37 #endif
38 
39 static struct imsgev		*iev_ui;
40 static struct tls_config	*tlsconf;
41 
42 struct req;
43 
44 static void		 die(void) __attribute__((__noreturn__));
45 
46 static void		 try_to_connect(int, short, void*);
47 
48 #if HAVE_ASR_RUN
49 static void		 query_done(struct asr_result*, void*);
50 static void		 async_conn_towards(struct req*);
51 #else
52 static void 		 blocking_conn_towards(struct req*);
53 #endif
54 
55 static void		 close_with_err(struct req*, const char*);
56 static void		 close_with_errf(struct req*, const char*, ...) __attribute__((format(printf, 2, 3)));
57 static struct req	*req_by_id(uint32_t);
58 static struct req	*req_by_id_try(uint32_t);
59 
60 static void		 setup_tls(struct req*);
61 static void		 do_handshake(int, short, void*);
62 static void		 write_request(int, short, void*);
63 static void		 read_reply(int, short, void*);
64 static void		 parse_reply(struct req*);
65 static void		 copy_body(int, short, void*);
66 
67 static void		 handle_get_raw(struct imsg *, size_t);
68 static void		 handle_cert_status(struct imsg*, size_t);
69 static void		 handle_proceed(struct imsg*, size_t);
70 static void		 handle_stop(struct imsg*, size_t);
71 static void		 handle_quit(struct imsg*, size_t);
72 static void		 handle_dispatch_imsg(int, short, void*);
73 
74 static int		 net_send_ui(int, uint32_t, const void *, uint16_t);
75 
76 /* TODO: making this customizable */
77 struct timeval timeout_for_handshake = { 5, 0 };
78 
79 static imsg_handlerfn *handlers[] = {
80 	[IMSG_GET_RAW]		= handle_get_raw,
81 	[IMSG_CERT_STATUS]	= handle_cert_status,
82 	[IMSG_PROCEED]		= handle_proceed,
83 	[IMSG_STOP]		= handle_stop,
84 	[IMSG_QUIT]		= handle_quit,
85 };
86 
87 typedef void (*statefn)(int, short, void*);
88 
89 TAILQ_HEAD(, req) reqhead;
90 /* a pending request */
91 struct req {
92 	struct event		 ev;
93 	struct phos_uri		 url;
94 	uint32_t		 id;
95 	int			 fd;
96 	struct tls		*ctx;
97 	char			 buf[1024];
98 	size_t			 off;
99 
100 	struct addrinfo		*servinfo, *p;
101 #if HAVE_ASR_RUN
102 	struct addrinfo		 hints;
103 	struct event_asr	*asrev;
104 #endif
105 
106 	TAILQ_ENTRY(req)	 reqs;
107 };
108 
109 static inline void
110 yield_r(struct req *req, statefn fn, struct timeval *tv)
111 {
112 	event_once(req->fd, EV_READ, fn, req, tv);
113 }
114 
115 static inline void
116 yield_w(struct req *req, statefn fn, struct timeval *tv)
117 {
118 	event_once(req->fd, EV_WRITE, fn, req, tv);
119 }
120 
121 static inline void
122 advance_buf(struct req *req, size_t len)
123 {
124 	assert(len <= req->off);
125 
126 	req->off -= len;
127 	memmove(req->buf, req->buf + len, req->off);
128 }
129 
130 static void __attribute__((__noreturn__))
131 die(void)
132 {
133 	abort(); 		/* TODO */
134 }
135 
136 static void
137 try_to_connect(int fd, short ev, void *d)
138 {
139 	struct req	*req = d;
140 	int		 error = 0;
141 	socklen_t	 len = sizeof(error);
142 
143 again:
144 	if (req->p == NULL)
145 		goto err;
146 
147 	if (req->fd != -1) {
148 		if (getsockopt(req->fd, SOL_SOCKET, SO_ERROR, &error, &len) == -1)
149 			goto err;
150 		if (error != 0) {
151                         errno = error;
152                         goto err;
153 		}
154 		goto done;
155 	}
156 
157 	req->fd = socket(req->p->ai_family, req->p->ai_socktype, req->p->ai_protocol);
158 	if (req->fd == -1) {
159 		req->p = req->p->ai_next;
160 		goto again;
161 	} else {
162 		mark_nonblock(req->fd);
163 		if (connect(req->fd, req->p->ai_addr, req->p->ai_addrlen) == 0)
164 			goto done;
165 		yield_w(req, try_to_connect, NULL);
166 	}
167 	return;
168 
169 err:
170 	freeaddrinfo(req->servinfo);
171 	close_with_errf(req, "failed to connect to %s",
172 	    req->url.host);
173 	return;
174 
175 done:
176 	freeaddrinfo(req->servinfo);
177 	setup_tls(req);
178 }
179 
180 #if HAVE_ASR_RUN
181 static void
182 query_done(struct asr_result *res, void *d)
183 {
184 	struct req	*req = d;
185 
186 	req->asrev = NULL;
187 	if (res->ar_gai_errno != 0) {
188 		close_with_errf(req, "failed to resolve %s: %s",
189 		    req->url.host, gai_strerror(res->ar_gai_errno));
190 		return;
191 	}
192 
193 	req->fd = -1;
194 	req->servinfo = res->ar_addrinfo;
195 	req->p = res->ar_addrinfo;
196 	try_to_connect(0, 0, req);
197 }
198 
199 static void
200 async_conn_towards(struct req *req)
201 {
202 	struct asr_query	*q;
203 	const char		*proto = "1965";
204 
205 	if (*req->url.port != '\0')
206 		proto = req->url.port;
207 
208 	req->hints.ai_family = AF_UNSPEC;
209 	req->hints.ai_socktype = SOCK_STREAM;
210 	q = getaddrinfo_async(req->url.host, proto, &req->hints, NULL);
211 	req->asrev = event_asr_run(q, query_done, req);
212 }
213 #else
214 static void
215 blocking_conn_towards(struct req *req)
216 {
217 	struct addrinfo	 hints;
218 	struct phos_uri	*url = &req->url;
219 	int		 status;
220 	const char	*proto = "1965";
221 
222 	if (*url->port != '\0')
223 		proto = url->port;
224 
225 	memset(&hints, 0, sizeof(hints));
226 	hints.ai_family = AF_UNSPEC;
227 	hints.ai_socktype = SOCK_STREAM;
228 
229 	if ((status = getaddrinfo(url->host, proto, &hints, &req->servinfo))) {
230 		close_with_errf(req, "failed to resolve %s: %s",
231 		    url->host, gai_strerror(status));
232 		return;
233 	}
234 
235 	req->fd = -1;
236 	req->p = req->servinfo;
237 	try_to_connect(0, 0, req);
238 }
239 #endif
240 
241 static struct req *
242 req_by_id(uint32_t id)
243 {
244 	struct req *r;
245 
246 	if ((r = req_by_id_try(id)) == NULL)
247 		die();
248 	return r;
249 }
250 
251 static struct req *
252 req_by_id_try(uint32_t id)
253 {
254 	struct req *r;
255 
256 	TAILQ_FOREACH(r, &reqhead, reqs) {
257 		if (r->id == id)
258 			return r;
259 	}
260 
261 	return NULL;
262 }
263 
264 static void
265 close_conn(int fd, short ev, void *d)
266 {
267 	struct req	*req = d;
268 
269 #if HAVE_ASR_RUN
270 	if (req->asrev != NULL)
271 		event_asr_abort(req->asrev);
272 #endif
273 
274 	if (req->ctx != NULL) {
275 		switch (tls_close(req->ctx)) {
276 		case TLS_WANT_POLLIN:
277 			yield_r(req, close_conn, NULL);
278 			return;
279 		case TLS_WANT_POLLOUT:
280 			yield_w(req, close_conn, NULL);
281 			return;
282 		}
283 
284 		tls_free(req->ctx);
285 	}
286 
287 	TAILQ_REMOVE(&reqhead, req, reqs);
288 	if (req->fd != -1)
289 		close(req->fd);
290 	free(req);
291 }
292 
293 static void
294 close_with_err(struct req *req, const char *err)
295 {
296 	net_send_ui(IMSG_ERR, req->id, err, strlen(err)+1);
297 	close_conn(0, 0, req);
298 }
299 
300 static void
301 close_with_errf(struct req *req, const char *fmt, ...)
302 {
303 	va_list	 ap;
304 	char	*s;
305 
306 	va_start(ap, fmt);
307 	if (vasprintf(&s, fmt, ap) == -1)
308 		abort();
309 	va_end(ap);
310 
311 	close_with_err(req, s);
312 	free(s);
313 }
314 
315 static void
316 setup_tls(struct req *req)
317 {
318 	if ((req->ctx = tls_client()) == NULL) {
319 		close_with_errf(req, "tls_client: %s", strerror(errno));
320 		return;
321 	}
322 	if (tls_configure(req->ctx, tlsconf) == -1) {
323 		close_with_errf(req, "tls_configure: %s", tls_error(req->ctx));
324 		return;
325 	}
326 	if (tls_connect_socket(req->ctx, req->fd, req->url.host) == -1) {
327 		close_with_errf(req, "tls_connect_socket: %s", tls_error(req->ctx));
328 		return;
329 	}
330 	yield_w(req, do_handshake, &timeout_for_handshake);
331 }
332 
333 static void
334 do_handshake(int fd, short ev, void *d)
335 {
336 	struct req	*req = d;
337 	const char	*hash;
338 
339 	if (ev == EV_TIMEOUT) {
340 		close_with_err(req, "Timeout loading page");
341 		return;
342 	}
343 
344 	switch (tls_handshake(req->ctx)) {
345 	case TLS_WANT_POLLIN:
346 		yield_r(req, do_handshake, NULL);
347 		return;
348 	case TLS_WANT_POLLOUT:
349 		yield_w(req, do_handshake, NULL);
350 		return;
351 	}
352 
353 	hash = tls_peer_cert_hash(req->ctx);
354 	if (hash == NULL) {
355 		close_with_errf(req, "handshake failed: %s", tls_error(req->ctx));
356 		return;
357 	}
358 	net_send_ui(IMSG_CHECK_CERT, req->id, hash, strlen(hash)+1);
359 }
360 
361 static void
362 write_request(int fd, short ev, void *d)
363 {
364 	struct req	*req = d;
365 	ssize_t		 r;
366 	size_t		 len;
367 
368 	len = strlen(req->buf);
369 
370 	switch (r = tls_write(req->ctx, req->buf, len)) {
371 	case -1:
372 		close_with_errf(req, "tls_write: %s", tls_error(req->ctx));
373 		break;
374 	case TLS_WANT_POLLIN:
375 		yield_r(req, write_request, NULL);
376 		break;
377 	case TLS_WANT_POLLOUT:
378 		yield_w(req, write_request, NULL);
379 		break;
380 	default:
381 		/* assume r == len */
382 		(void)r;
383 		yield_r(req, read_reply, NULL);
384 		break;
385 	}
386 }
387 
388 static void
389 read_reply(int fd, short ev, void *d)
390 {
391 	struct req	*req = d;
392 	size_t		 len;
393 	ssize_t		 r;
394 	char		*buf;
395 
396 	buf = req->buf + req->off;
397 	len = sizeof(req->buf) - req->off;
398 
399 	switch (r = tls_read(req->ctx, buf, len)) {
400 	case -1:
401 		close_with_errf(req, "tls_read: %s", tls_error(req->ctx));
402 		break;
403 	case TLS_WANT_POLLIN:
404 		yield_r(req, read_reply, NULL);
405 		break;
406 	case TLS_WANT_POLLOUT:
407 		yield_w(req, read_reply, NULL);
408 		break;
409 	default:
410 		req->off += r;
411 
412 		if (memmem(req->buf, req->off, "\r\n", 2) != NULL)
413 			parse_reply(req);
414 		else if (req->off == sizeof(req->buf))
415 			close_with_err(req, "invalid response");
416 		else
417 			yield_r(req, read_reply, NULL);
418 		break;
419 	}
420 }
421 
422 static void
423 parse_reply(struct req *req)
424 {
425 	int	 code;
426 	char	*e;
427 	size_t	 len;
428 
429 	if (req->off < 4)
430 		goto err;
431 
432 	if (!isdigit(req->buf[0]) || !isdigit(req->buf[1]))
433 		goto err;
434 
435 	code = (req->buf[0] - '0')*10 + (req->buf[1] - '0');
436 
437 	if (!isspace(req->buf[2]))
438 		goto err;
439 
440 	advance_buf(req, 3);
441 	if ((e = memmem(req->buf, req->off, "\r\n", 2)) == NULL)
442 		goto err;
443 
444 	*e = '\0';
445 	e++;
446 	len = e - req->buf;
447 	net_send_ui(IMSG_GOT_CODE, req->id, &code, sizeof(code));
448 	net_send_ui(IMSG_GOT_META, req->id, req->buf, len);
449 
450 	if (20 <= code && code < 30)
451 		advance_buf(req, len+1); /* skip \n too */
452 	else
453 		close_conn(0, 0, req);
454 
455 	return;
456 
457 err:
458 	close_with_err(req, "malformed request");
459 }
460 
461 static void
462 copy_body(int fd, short ev, void *d)
463 {
464 	struct req	*req = d;
465 	ssize_t		 r;
466 
467 	for (;;) {
468 		if (req->off != 0) {
469 			net_send_ui(IMSG_BUF, req->id,
470 			    req->buf, req->off);
471 			req->off = 0;
472 		}
473 
474 		switch (r = tls_read(req->ctx, req->buf, sizeof(req->buf))) {
475 		case TLS_WANT_POLLIN:
476 			yield_r(req, copy_body, NULL);
477 			return;
478 		case TLS_WANT_POLLOUT:
479 			yield_w(req, copy_body, NULL);
480 			return;
481 		case 0:
482 			net_send_ui(IMSG_EOF, req->id, NULL, 0);
483 			close_conn(0, 0, req);
484 			return;
485 		default:
486 			req->off = r;
487 		}
488 	}
489 }
490 
491 static void
492 handle_get_raw(struct imsg *imsg, size_t datalen)
493 {
494 	struct req	*req;
495 	struct get_req	*r;
496 
497 	r = imsg->data;
498 
499 	if (datalen != sizeof(*r))
500 		die();
501 
502 	if ((req = calloc(1, sizeof(*req))) == NULL)
503 		die();
504 
505 	req->id = imsg->hdr.peerid;
506 	TAILQ_INSERT_HEAD(&reqhead, req, reqs);
507 
508 	strlcpy(req->url.host, r->host, sizeof(req->url.host));
509 	strlcpy(req->url.port, r->port, sizeof(req->url.port));
510 	strlcpy(req->buf, r->req, sizeof(req->buf));
511 
512 #if HAVE_ASR_RUN
513         async_conn_towards(req);
514 #else
515 	blocking_conn_towards(req);
516 #endif
517 }
518 
519 static void
520 handle_cert_status(struct imsg *imsg, size_t datalen)
521 {
522 	struct req	*req;
523 	int		 is_ok;
524 
525 	req = req_by_id(imsg->hdr.peerid);
526 
527 	if (datalen < sizeof(is_ok))
528 		die();
529 	memcpy(&is_ok, imsg->data, sizeof(is_ok));
530 
531 	if (is_ok)
532 		yield_w(req, write_request, NULL);
533 	else
534 		close_conn(0, 0, req);
535 }
536 
537 static void
538 handle_proceed(struct imsg *imsg, size_t datalen)
539 {
540 	yield_r(req_by_id(imsg->hdr.peerid),
541 	    copy_body, NULL);
542 }
543 
544 static void
545 handle_stop(struct imsg *imsg, size_t datalen)
546 {
547 	struct req	*req;
548 
549 	if ((req = req_by_id_try(imsg->hdr.peerid)) == NULL)
550 		return;
551 	close_conn(0, 0, req);
552 }
553 
554 static void
555 handle_quit(struct imsg *imsg, size_t datalen)
556 {
557 	event_loopbreak();
558 }
559 
560 static void
561 handle_dispatch_imsg(int fd, short ev, void *d)
562 {
563 	struct imsgev	*iev = d;
564 	dispatch_imsg(iev, ev, handlers, sizeof(handlers));
565 }
566 
567 static int
568 net_send_ui(int type, uint32_t peerid, const void *data,
569     uint16_t datalen)
570 {
571 	return imsg_compose_event(iev_ui, type, peerid, 0, -1,
572 	    data, datalen);
573 }
574 
575 int
576 client_main(void)
577 {
578 	setproctitle("net");
579 
580 	TAILQ_INIT(&reqhead);
581 
582 	if ((tlsconf = tls_config_new()) == NULL)
583 		die();
584 	tls_config_insecure_noverifycert(tlsconf);
585 	tls_config_insecure_noverifyname(tlsconf);
586 
587 	event_init();
588 
589 	/* Setup pipe and event handler to the main process */
590 	if ((iev_ui = malloc(sizeof(*iev_ui))) == NULL)
591 		die();
592 	imsg_init(&iev_ui->ibuf, 3);
593 	iev_ui->handler = handle_dispatch_imsg;
594 	iev_ui->events = EV_READ;
595 	event_set(&iev_ui->ev, iev_ui->ibuf.fd, iev_ui->events,
596 	    iev_ui->handler, iev_ui);
597 	event_add(&iev_ui->ev, NULL);
598 
599 	sandbox_net_process();
600 
601 	event_dispatch();
602 	return 0;
603 }