accf_http.c revision 95552 
1/*
2 * Copyright (c) 2000 Paycounter, Inc.
3 * Author: Alfred Perlstein <alfred@paycounter.com>, <alfred@FreeBSD.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 *	$FreeBSD: head/sys/netinet/accf_http.c 95552 2002-04-27 08:24:29Z tanimura $
28 */
29
30#define ACCEPT_FILTER_MOD
31
32#include <sys/param.h>
33#include <sys/kernel.h>
34#include <sys/sysctl.h>
35#include <sys/socketvar.h>
36#include <sys/mbuf.h>
37
38/* check for GET/HEAD */
39static void sohashttpget(struct socket *so, void *arg, int waitflag);
40/* check for HTTP/1.0 or HTTP/1.1 */
41static void soparsehttpvers(struct socket *so, void *arg, int waitflag);
42/* check for end of HTTP/1.x request */
43static void soishttpconnected(struct socket *so, void *arg, int waitflag);
44/* strcmp on an mbuf chain */
45static int mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, char *cmp);
46/* strncmp on an mbuf chain */
47static int mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset,
48	int max, char *cmp);
49/* socketbuffer is full */
50static int sbfull(struct sockbuf *sb);
51
52static struct accept_filter accf_http_filter = {
53	"httpready",
54	sohashttpget,
55	NULL,
56	NULL
57};
58
59static moduledata_t accf_http_mod = {
60	"accf_http",
61	accept_filt_generic_mod_event,
62	&accf_http_filter
63};
64
65DECLARE_MODULE(accf_http, accf_http_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE);
66
67static int parse_http_version = 1;
68
69SYSCTL_NODE(_net_inet_accf, OID_AUTO, http, CTLFLAG_RW, 0,
70"HTTP accept filter");
71SYSCTL_INT(_net_inet_accf_http, OID_AUTO, parsehttpversion, CTLFLAG_RW,
72&parse_http_version, 1,
73"Parse http version so that non 1.x requests work");
74
75#ifdef ACCF_HTTP_DEBUG
76#define DPRINT(fmt, args...) \
77	do {	\
78		printf("%s:%d: " fmt "\n", __func__, __LINE__ , ##args);	\
79	} while (0)
80#else
81#define DPRINT(fmt, args...)
82#endif
83
84static int
85sbfull(struct sockbuf *sb)
86{
87
88	DPRINT("sbfull, cc(%ld) >= hiwat(%ld): %d, mbcnt(%ld) >= mbmax(%ld): %d",
89		sb->sb_cc, sb->sb_hiwat, sb->sb_cc >= sb->sb_hiwat,
90		sb->sb_mbcnt, sb->sb_mbmax, sb->sb_mbcnt >= sb->sb_mbmax);
91	return(sb->sb_cc >= sb->sb_hiwat || sb->sb_mbcnt >= sb->sb_mbmax);
92}
93
94/*
95 * start at mbuf m, (must provide npkt if exists)
96 * starting at offset in m compare characters in mbuf chain for 'cmp'
97 */
98static int
99mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, char *cmp)
100{
101	struct mbuf *n;
102
103	for (;m != NULL; m = n) {
104		n = npkt;
105		if (npkt)
106			npkt = npkt->m_nextpkt;
107		for (; m; m = m->m_next) {
108			for (; offset < m->m_len; offset++, cmp++) {
109				if (*cmp == '\0') {
110					return (1);
111				} else if (*cmp != *(mtod(m, char *) + offset)) {
112					return (0);
113				}
114			}
115			offset = 0;
116		}
117	}
118	return (0);
119}
120
121/*
122 * start at mbuf m, (must provide npkt if exists)
123 * starting at offset in m compare characters in mbuf chain for 'cmp'
124 * stop at 'max' characters
125 */
126static int
127mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset, int max, char *cmp)
128{
129	struct mbuf *n;
130
131	for (;m != NULL; m = n) {
132		n = npkt;
133		if (npkt)
134			npkt = npkt->m_nextpkt;
135		for (; m; m = m->m_next) {
136			for (; offset < m->m_len; offset++, cmp++, max--) {
137				if (max == 0 || *cmp == '\0') {
138					return (1);
139				} else if (*cmp != *(mtod(m, char *) + offset)) {
140					return (0);
141				}
142			}
143			offset = 0;
144		}
145	}
146	return (0);
147}
148
149#define STRSETUP(sptr, slen, str) \
150	do {	\
151		sptr = str;	\
152		slen = sizeof(str) - 1;	\
153	} while(0)
154
155static void
156sohashttpget(struct socket *so, void *arg, int waitflag)
157{
158
159	if ((so->so_state & SS_CANTRCVMORE) == 0 && !sbfull(&so->so_rcv)) {
160		struct mbuf *m;
161		char *cmp;
162		int	cmplen, cc;
163
164		m = so->so_rcv.sb_mb;
165		cc = so->so_rcv.sb_cc - 1;
166		if (cc < 1)
167			return;
168		switch (*mtod(m, char *)) {
169		case 'G':
170			STRSETUP(cmp, cmplen, "ET ");
171			break;
172		case 'H':
173			STRSETUP(cmp, cmplen, "EAD ");
174			break;
175		default:
176			goto fallout;
177		}
178		if (cc < cmplen) {
179			if (mbufstrncmp(m, m->m_nextpkt, 1, cc, cmp) == 1) {
180				DPRINT("short cc (%d) but mbufstrncmp ok", cc);
181				return;
182			} else {
183				DPRINT("short cc (%d) mbufstrncmp failed", cc);
184				goto fallout;
185			}
186		}
187		if (mbufstrcmp(m, m->m_nextpkt, 1, cmp) == 1) {
188			DPRINT("mbufstrcmp ok");
189			if (parse_http_version == 0)
190				soishttpconnected(so, arg, waitflag);
191			else
192				soparsehttpvers(so, arg, waitflag);
193			return;
194		}
195		DPRINT("mbufstrcmp bad");
196	}
197
198fallout:
199	DPRINT("fallout");
200	SIGIO_SLOCK();
201	so->so_upcall = NULL;
202	so->so_rcv.sb_flags &= ~SB_UPCALL;
203	soisconnected_locked(so);
204	SIGIO_SUNLOCK();
205	return;
206}
207
208static void
209soparsehttpvers(struct socket *so, void *arg, int waitflag)
210{
211	struct mbuf *m, *n;
212	int	i, cc, spaces, inspaces;
213
214	if ((so->so_state & SS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv))
215		goto fallout;
216
217	m = so->so_rcv.sb_mb;
218	cc = so->so_rcv.sb_cc;
219	inspaces = spaces = 0;
220	for (m = so->so_rcv.sb_mb; m; m = n) {
221		n = m->m_nextpkt;
222		for (; m; m = m->m_next) {
223			for (i = 0; i < m->m_len; i++, cc--) {
224				switch (*(mtod(m, char *) + i)) {
225				case ' ':
226					if (!inspaces) {
227						spaces++;
228						inspaces = 1;
229					}
230					break;
231				case '\r':
232				case '\n':
233					DPRINT("newline");
234					goto fallout;
235				default:
236					if (spaces == 2) {
237						/* make sure we have enough data left */
238						if (cc < sizeof("HTTP/1.0") - 1) {
239							if (mbufstrncmp(m, n, i, cc, "HTTP/1.") == 1) {
240								DPRINT("mbufstrncmp ok");
241								goto readmore;
242							} else {
243								DPRINT("mbufstrncmp bad");
244								goto fallout;
245							}
246						} else if (mbufstrcmp(m, n, i, "HTTP/1.0") == 1 ||
247									mbufstrcmp(m, n, i, "HTTP/1.1") == 1) {
248								DPRINT("mbufstrcmp ok");
249								soishttpconnected(so, arg, waitflag);
250								return;
251						} else {
252							DPRINT("mbufstrcmp bad");
253							goto fallout;
254						}
255					}
256					inspaces = 0;
257					break;
258				}
259			}
260		}
261	}
262readmore:
263	DPRINT("readmore");
264	/*
265	 * if we hit here we haven't hit something
266	 * we don't understand or a newline, so try again
267	 */
268	so->so_upcall = soparsehttpvers;
269	so->so_rcv.sb_flags |= SB_UPCALL;
270	return;
271
272fallout:
273	DPRINT("fallout");
274	SIGIO_SLOCK();
275	so->so_upcall = NULL;
276	so->so_rcv.sb_flags &= ~SB_UPCALL;
277	soisconnected_locked(so);
278	SIGIO_SUNLOCK();
279	return;
280}
281
282
283#define NCHRS 3
284
285static void
286soishttpconnected(struct socket *so, void *arg, int waitflag)
287{
288	char a, b, c;
289	struct mbuf *m, *n;
290	int ccleft, copied;
291
292	DPRINT("start");
293	if ((so->so_state & SS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv))
294		goto gotit;
295
296	/*
297	 * Walk the socketbuffer and copy the last NCHRS (3) into a, b, and c
298	 * copied - how much we've copied so far
299	 * ccleft - how many bytes remaining in the socketbuffer
300	 * just loop over the mbufs subtracting from 'ccleft' until we only
301	 * have NCHRS left
302	 */
303	copied = 0;
304	ccleft = so->so_rcv.sb_cc;
305	if (ccleft < NCHRS)
306		goto readmore;
307	a = b = c = '\0';
308	for (m = so->so_rcv.sb_mb; m; m = n) {
309		n = m->m_nextpkt;
310		for (; m; m = m->m_next) {
311			ccleft -= m->m_len;
312			if (ccleft <= NCHRS) {
313				char *src;
314				int tocopy;
315
316				tocopy = (NCHRS - ccleft) - copied;
317				src = mtod(m, char *) + (m->m_len - tocopy);
318
319				while (tocopy--) {
320					switch (copied++) {
321					case 0:
322						a = *src++;
323						break;
324					case 1:
325						b = *src++;
326						break;
327					case 2:
328						c = *src++;
329						break;
330					}
331				}
332			}
333		}
334	}
335	if (c == '\n' && (b == '\n' || (b == '\r' && a == '\n'))) {
336		/* we have all request headers */
337		goto gotit;
338	}
339
340readmore:
341	so->so_upcall = soishttpconnected;
342	so->so_rcv.sb_flags |= SB_UPCALL;
343	return;
344
345gotit:
346	SIGIO_SLOCK();
347	so->so_upcall = NULL;
348	so->so_rcv.sb_flags &= ~SB_UPCALL;
349	soisconnected_locked(so);
350	SIGIO_SUNLOCK();
351	return;
352}
353