libwebsockets/test-server/test-server-http.c

/*
 * libwebsockets-test-server - libwebsockets test implementation
 *
 * Copyright (C) 2010-2015 Andy Green <andy@warmcat.com>
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation:
 *  version 2.1 of the License.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 *  MA  02110-1301  USA
 */
#include "test-server.h"

/*
 * This demo server shows how to use libwebsockets for one or more
 * websocket protocols in the same server
 *
 * It defines the following websocket protocols:
 *
 *  dumb-increment-protocol:  once the socket is opened, an incrementing
 *				ascii string is sent down it every 50ms.
 *				If you send "reset\n" on the websocket, then
 *				the incrementing number is reset to 0.
 *
 *  lws-mirror-protocol: copies any received packet to every connection also
 *				using this protocol, including the sender
 */

enum demo_protocols {
	/* always first */
	PROTOCOL_HTTP = 0,

	PROTOCOL_DUMB_INCREMENT,
	PROTOCOL_LWS_MIRROR,

	/* always last */
	DEMO_PROTOCOL_COUNT
};

/*
 * We take a strict whitelist approach to stop ../ attacks
 */
struct serveable {
	const char *urlpath;
	const char *mimetype;
};

/*
 * this is just an example of parsing handshake headers, you don't need this
 * in your code unless you will filter allowing connections by the header
 * content
 */
void
dump_handshake_info(struct lws *wsi)
{
	int n = 0;
	char buf[256];
	const unsigned char *c;

	do {
		c = lws_token_to_string(n);
		if (!c) {
			n++;
			continue;
		}

		if (!lws_hdr_total_length(wsi, n)) {
			n++;
			continue;
		}

		lws_hdr_copy(wsi, buf, sizeof buf, n);

		fprintf(stderr, "    %s = %s\n", (char *)c, buf);
		n++;
	} while (c);
}

const char * get_mimetype(const char *file)
{
	int n = strlen(file);

	if (n < 5)
		return NULL;

	if (!strcmp(&file[n - 4], ".ico"))
		return "image/x-icon";

	if (!strcmp(&file[n - 4], ".png"))
		return "image/png";

	if (!strcmp(&file[n - 5], ".html"))
		return "text/html";

	return NULL;
}

/* this protocol server (always the first one) handles HTTP,
 *
 * Some misc callbacks that aren't associated with a protocol also turn up only
 * here on the first protocol server.
 */

int callback_http(struct lws *wsi, enum lws_callback_reasons reason, void *user,
		  void *in, size_t len)
{
	struct per_session_data__http *pss =
			(struct per_session_data__http *)user;
	static unsigned char buffer[4096];
	unsigned long amount, file_len;
	char leaf_path[1024];
	const char *mimetype;
	char *other_headers;
	unsigned char *end;
	struct timeval tv;
	unsigned char *p;
	char buf[256];
	char b64[64];
	int n, m;

#ifdef EXTERNAL_POLL
	struct lws_pollargs *pa = (struct lws_pollargs *)in;
#endif

	switch (reason) {
	case LWS_CALLBACK_HTTP:

		dump_handshake_info(wsi);

		/* dump the individual URI Arg parameters */
		n = 0;
		while (lws_hdr_copy_fragment(wsi, buf, sizeof(buf),
					     WSI_TOKEN_HTTP_URI_ARGS, n) > 0) {
			lwsl_info("URI Arg %d: %s\n", ++n, buf);
		}

		if (len < 1) {
			lws_return_http_status(wsi,
						HTTP_STATUS_BAD_REQUEST, NULL);
			goto try_to_reuse;
		}

		/* this example server has no concept of directories */
		if (strchr((const char *)in + 1, '/')) {
			lws_return_http_status(wsi,
					       HTTP_STATUS_FORBIDDEN, NULL);
			goto try_to_reuse;
		}

		/* if a legal POST URL, let it continue and accept data */
		if (lws_hdr_total_length(wsi, WSI_TOKEN_POST_URI))
			return 0;

		/* check for the "send a big file by hand" example case */

		if (!strcmp((const char *)in, "/leaf.jpg")) {
			if (strlen(resource_path) > sizeof(leaf_path) - 10)
				return -1;
			sprintf(leaf_path, "%s/leaf.jpg", resource_path);

			/* well, let's demonstrate how to send the hard way */

			p = buffer + LWS_SEND_BUFFER_PRE_PADDING;
			end = p + sizeof(buffer) - LWS_SEND_BUFFER_PRE_PADDING;

			pss->fd = lws_plat_file_open(wsi, leaf_path, &file_len,
						     LWS_O_RDONLY);

			if (pss->fd == LWS_INVALID_FILE)
				return -1;

			/*
			 * we will send a big jpeg file, but it could be
			 * anything.  Set the Content-Type: appropriately
			 * so the browser knows what to do with it.
			 *
			 * Notice we use the APIs to build the header, which
			 * will do the right thing for HTTP 1/1.1 and HTTP2
			 * depending on what connection it happens to be working
			 * on
			 */
			if (lws_add_http_header_status(wsi, 200, &p, end))
				return 1;
			if (lws_add_http_header_by_token(wsi, WSI_TOKEN_HTTP_SERVER,
				    	(unsigned char *)"libwebsockets",
					13, &p, end))
				return 1;
			if (lws_add_http_header_by_token(wsi,
					WSI_TOKEN_HTTP_CONTENT_TYPE,
				    	(unsigned char *)"image/jpeg",
					10, &p, end))
				return 1;
			if (lws_add_http_header_content_length(wsi,
							       file_len, &p,
							       end))
				return 1;
			if (lws_finalize_http_header(wsi, &p, end))
				return 1;

			/*
			 * send the http headers...
			 * this won't block since it's the first payload sent
			 * on the connection since it was established
			 * (too small for partial)
			 *
			 * Notice they are sent using LWS_WRITE_HTTP_HEADERS
			 * which also means you can't send body too in one step,
			 * this is mandated by changes in HTTP2
			 */

			n = lws_write(wsi, buffer + LWS_SEND_BUFFER_PRE_PADDING,
				      p - (buffer + LWS_SEND_BUFFER_PRE_PADDING),
				      LWS_WRITE_HTTP_HEADERS);

			if (n < 0) {
				lws_plat_file_close(wsi, pss->fd);
				return -1;
			}
			/*
			 * book us a LWS_CALLBACK_HTTP_WRITEABLE callback
			 */
			lws_callback_on_writable(wsi);
			break;
		}

		/* if not, send a file the easy way */
		strcpy(buf, resource_path);
		if (strcmp(in, "/")) {
			if (*((const char *)in) != '/')
				strcat(buf, "/");
			strncat(buf, in, sizeof(buf) - strlen(resource_path));
		} else /* default file to serve */
			strcat(buf, "/test.html");
		buf[sizeof(buf) - 1] = '\0';

		/* refuse to serve files we don't understand */
		mimetype = get_mimetype(buf);
		if (!mimetype) {
			lwsl_err("Unknown mimetype for %s\n", buf);
			lws_return_http_status(wsi,
				      HTTP_STATUS_UNSUPPORTED_MEDIA_TYPE, NULL);
			return -1;
		}

		/* demonstrates how to set a cookie on / */

		other_headers = NULL;
		n = 0;
		if (!strcmp((const char *)in, "/") &&
			   !lws_hdr_total_length(wsi, WSI_TOKEN_HTTP_COOKIE)) {
			/* this isn't very unguessable but it'll do for us */
			gettimeofday(&tv, NULL);
			n = sprintf(b64, "test=LWS_%u_%u_COOKIE;Max-Age=360000",
				(unsigned int)tv.tv_sec,
				(unsigned int)tv.tv_usec);

			p = (unsigned char *)leaf_path;

			if (lws_add_http_header_by_name(wsi,
				(unsigned char *)"set-cookie:",
				(unsigned char *)b64, n, &p,
				(unsigned char *)leaf_path + sizeof(leaf_path)))
				return 1;
			n = (char *)p - leaf_path;
			other_headers = leaf_path;
		}

		n = lws_serve_http_file(wsi, buf, mimetype, other_headers, n);
		if (n < 0 || ((n > 0) && lws_http_transaction_completed(wsi)))
			return -1; /* error or can't reuse connection: close the socket */

		/*
		 * notice that the sending of the file completes asynchronously,
		 * we'll get a LWS_CALLBACK_HTTP_FILE_COMPLETION callback when
		 * it's done
		 */

		break;

	case LWS_CALLBACK_HTTP_BODY:
		strncpy(buf, in, 20);
		buf[20] = '\0';
		if (len < 20)
			buf[len] = '\0';

		lwsl_notice("LWS_CALLBACK_HTTP_BODY: %s... len %d\n",
				(const char *)buf, (int)len);

		break;

	case LWS_CALLBACK_HTTP_BODY_COMPLETION:
		lwsl_notice("LWS_CALLBACK_HTTP_BODY_COMPLETION\n");
		/* the whole of the sent body arrived, close or reuse the connection */
		lws_return_http_status(wsi, HTTP_STATUS_OK, NULL);
		goto try_to_reuse;

	case LWS_CALLBACK_HTTP_FILE_COMPLETION:
		goto try_to_reuse;

	case LWS_CALLBACK_HTTP_WRITEABLE:
		/*
		 * we can send more of whatever it is we were sending
		 */
		do {
			/* we'd like the send this much */
			n = sizeof(buffer) - LWS_SEND_BUFFER_PRE_PADDING;

			/* but if the peer told us he wants less, we can adapt */
			m = lws_get_peer_write_allowance(wsi);

			/* -1 means not using a protocol that has this info */
			if (m == 0)
				/* right now, peer can't handle anything */
				goto later;

			if (m != -1 && m < n)
				/* he couldn't handle that much */
				n = m;

			n = lws_plat_file_read(wsi, pss->fd,
					       &amount, buffer +
					        LWS_SEND_BUFFER_PRE_PADDING, n);
			/* problem reading, close conn */
			if (n < 0)
				goto bail;
			n = (int)amount;
			/* sent it all, close conn */
			if (n == 0)
				goto flush_bail;
			/*
			 * To support HTTP2, must take care about preamble space
			 *
			 * identification of when we send the last payload frame
			 * is handled by the library itself if you sent a
			 * content-length header
			 */
			m = lws_write(wsi, buffer + LWS_SEND_BUFFER_PRE_PADDING,
				      n, LWS_WRITE_HTTP);
			if (m < 0)
				/* write failed, close conn */
				goto bail;

			/*
			 * http2 won't do this
			 */
			if (m != n)
				/* partial write, adjust */
				if (lws_plat_file_seek_cur(wsi, pss->fd, m - n) ==
							     (unsigned long)-1)
					goto bail;

			if (m) /* while still active, extend timeout */
				lws_set_timeout(wsi,
						PENDING_TIMEOUT_HTTP_CONTENT, 5);

			/* if we have indigestion, let him clear it
			 * before eating more */
			if (lws_partial_buffered(wsi))
				break;

		} while (!lws_send_pipe_choked(wsi));

later:
		lws_callback_on_writable(wsi);
		break;
flush_bail:
		/* true if still partial pending */
		if (lws_partial_buffered(wsi)) {
			lws_callback_on_writable(wsi);
			break;
		}
		lws_plat_file_close(wsi, pss->fd);
		goto try_to_reuse;

bail:
		lws_plat_file_close(wsi, pss->fd);
		return -1;

	/*
	 * callback for confirming to continue with client IP appear in
	 * protocol 0 callback since no websocket protocol has been agreed
	 * yet.  You can just ignore this if you won't filter on client IP
	 * since the default uhandled callback return is 0 meaning let the
	 * connection continue.
	 */
	case LWS_CALLBACK_FILTER_NETWORK_CONNECTION:

		/* if we returned non-zero from here, we kill the connection */
		break;

	/*
	 * callbacks for managing the external poll() array appear in
	 * protocol 0 callback
	 */

	case LWS_CALLBACK_LOCK_POLL:
		/*
		 * lock mutex to protect pollfd state
		 * called before any other POLL related callback
		 * if protecting wsi lifecycle change, len == 1
		 */
		test_server_lock(len);
		break;

	case LWS_CALLBACK_UNLOCK_POLL:
		/*
		 * unlock mutex to protect pollfd state when
		 * called after any other POLL related callback
		 * if protecting wsi lifecycle change, len == 1
		 */
		test_server_unlock(len);
		break;

#ifdef EXTERNAL_POLL
	case LWS_CALLBACK_ADD_POLL_FD:

		if (count_pollfds >= max_poll_elements) {
			lwsl_err("LWS_CALLBACK_ADD_POLL_FD: too many sockets to track\n");
			return 1;
		}

		fd_lookup[pa->fd] = count_pollfds;
		pollfds[count_pollfds].fd = pa->fd;
		pollfds[count_pollfds].events = pa->events;
		pollfds[count_pollfds++].revents = 0;
		break;

	case LWS_CALLBACK_DEL_POLL_FD:
		if (!--count_pollfds)
			break;
		m = fd_lookup[pa->fd];
		/* have the last guy take up the vacant slot */
		pollfds[m] = pollfds[count_pollfds];
		fd_lookup[pollfds[count_pollfds].fd] = m;
		break;

	case LWS_CALLBACK_CHANGE_MODE_POLL_FD:
	        pollfds[fd_lookup[pa->fd]].events = pa->events;
		break;
#endif

	case LWS_CALLBACK_GET_THREAD_ID:
		/*
		 * if you will call "lws_callback_on_writable"
		 * from a different thread, return the caller thread ID
		 * here so lws can use this information to work out if it
		 * should signal the poll() loop to exit and restart early
		 */

		/* return pthread_getthreadid_np(); */

		break;

	default:
		break;
	}

	return 0;

	/* if we're on HTTP1.1 or 2.0, will keep the idle connection alive */
try_to_reuse:
	if (lws_http_transaction_completed(wsi))
		return -1;

	return 0;
}