accf_http.c revision 95759 
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 95759 2002-04-30 01:54:54Z tanimura $
28 */
29
30#define ACCEPT_FILTER_MOD
31
32#include <sys/param.h>
33#include <sys/kernel.h>
34#include <sys/lock.h>
35#include <sys/mbuf.h>
36#include <sys/signalvar.h>
37#include <sys/sysctl.h>
38#include <sys/socketvar.h>
39#include <sys/sx.h>
40
41/* check for GET/HEAD */
42static void sohashttpget(struct socket *so, void *arg, int waitflag);
43/* check for HTTP/1.0 or HTTP/1.1 */
44static void soparsehttpvers(struct socket *so, void *arg, int waitflag);
45/* check for end of HTTP/1.x request */
46static void soishttpconnected(struct socket *so, void *arg, int waitflag);
47/* strcmp on an mbuf chain */
48static int mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, char *cmp);
49/* strncmp on an mbuf chain */
50static int mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset,
51	int max, char *cmp);
52/* socketbuffer is full */
53static int sbfull(struct sockbuf *sb);
54
55static struct accept_filter accf_http_filter = {
56	"httpready",
57	sohashttpget,
58	NULL,
59	NULL
60};
61
62static moduledata_t accf_http_mod = {
63	"accf_http",
64	accept_filt_generic_mod_event,
65	&accf_http_filter
66};
67
68DECLARE_MODULE(accf_http, accf_http_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE);
69
70static int parse_http_version = 1;
71
72SYSCTL_NODE(_net_inet_accf, OID_AUTO, http, CTLFLAG_RW, 0,
73"HTTP accept filter");
74SYSCTL_INT(_net_inet_accf_http, OID_AUTO, parsehttpversion, CTLFLAG_RW,
75&parse_http_version, 1,
76"Parse http version so that non 1.x requests work");
77
78#ifdef ACCF_HTTP_DEBUG
79#define DPRINT(fmt, args...) \
80	do {	\
81		printf("%s:%d: " fmt "\n", __func__, __LINE__ , ##args);	\
82	} while (0)
83#else
84#define DPRINT(fmt, args...)
85#endif
86
87static int
88sbfull(struct sockbuf *sb)
89{
90
91	DPRINT("sbfull, cc(%ld) >= hiwat(%ld): %d, mbcnt(%ld) >= mbmax(%ld): %d",
92		sb->sb_cc, sb->sb_hiwat, sb->sb_cc >= sb->sb_hiwat,
93		sb->sb_mbcnt, sb->sb_mbmax, sb->sb_mbcnt >= sb->sb_mbmax);
94	return(sb->sb_cc >= sb->sb_hiwat || sb->sb_mbcnt >= sb->sb_mbmax);
95}
96
97/*
98 * start at mbuf m, (must provide npkt if exists)
99 * starting at offset in m compare characters in mbuf chain for 'cmp'
100 */
101static int
102mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, char *cmp)
103{
104	struct mbuf *n;
105
106	for (;m != NULL; m = n) {
107		n = npkt;
108		if (npkt)
109			npkt = npkt->m_nextpkt;
110		for (; m; m = m->m_next) {
111			for (; offset < m->m_len; offset++, cmp++) {
112				if (*cmp == '\0') {
113					return (1);
114				} else if (*cmp != *(mtod(m, char *) + offset)) {
115					return (0);
116				}
117			}
118			offset = 0;
119		}
120	}
121	return (0);
122}
123
124/*
125 * start at mbuf m, (must provide npkt if exists)
126 * starting at offset in m compare characters in mbuf chain for 'cmp'
127 * stop at 'max' characters
128 */
129static int
130mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset, int max, char *cmp)
131{
132	struct mbuf *n;
133
134	for (;m != NULL; m = n) {
135		n = npkt;
136		if (npkt)
137			npkt = npkt->m_nextpkt;
138		for (; m; m = m->m_next) {
139			for (; offset < m->m_len; offset++, cmp++, max--) {
140				if (max == 0 || *cmp == '\0') {
141					return (1);
142				} else if (*cmp != *(mtod(m, char *) + offset)) {
143					return (0);
144				}
145			}
146			offset = 0;
147		}
148	}
149	return (0);
150}
151
152#define STRSETUP(sptr, slen, str) \
153	do {	\
154		sptr = str;	\
155		slen = sizeof(str) - 1;	\
156	} while(0)
157
158static void
159sohashttpget(struct socket *so, void *arg, int waitflag)
160{
161
162	if ((so->so_state & SS_CANTRCVMORE) == 0 && !sbfull(&so->so_rcv)) {
163		struct mbuf *m;
164		char *cmp;
165		int	cmplen, cc;
166
167		m = so->so_rcv.sb_mb;
168		cc = so->so_rcv.sb_cc - 1;
169		if (cc < 1)
170			return;
171		switch (*mtod(m, char *)) {
172		case 'G':
173			STRSETUP(cmp, cmplen, "ET ");
174			break;
175		case 'H':
176			STRSETUP(cmp, cmplen, "EAD ");
177			break;
178		default:
179			goto fallout;
180		}
181		if (cc < cmplen) {
182			if (mbufstrncmp(m, m->m_nextpkt, 1, cc, cmp) == 1) {
183				DPRINT("short cc (%d) but mbufstrncmp ok", cc);
184				return;
185			} else {
186				DPRINT("short cc (%d) mbufstrncmp failed", cc);
187				goto fallout;
188			}
189		}
190		if (mbufstrcmp(m, m->m_nextpkt, 1, cmp) == 1) {
191			DPRINT("mbufstrcmp ok");
192			if (parse_http_version == 0)
193				soishttpconnected(so, arg, waitflag);
194			else
195				soparsehttpvers(so, arg, waitflag);
196			return;
197		}
198		DPRINT("mbufstrcmp bad");
199	}
200
201fallout:
202	DPRINT("fallout");
203	SIGIO_SLOCK();
204	so->so_upcall = NULL;
205	so->so_rcv.sb_flags &= ~SB_UPCALL;
206	soisconnected_locked(so);
207	SIGIO_SUNLOCK();
208	return;
209}
210
211static void
212soparsehttpvers(struct socket *so, void *arg, int waitflag)
213{
214	struct mbuf *m, *n;
215	int	i, cc, spaces, inspaces;
216
217	if ((so->so_state & SS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv))
218		goto fallout;
219
220	m = so->so_rcv.sb_mb;
221	cc = so->so_rcv.sb_cc;
222	inspaces = spaces = 0;
223	for (m = so->so_rcv.sb_mb; m; m = n) {
224		n = m->m_nextpkt;
225		for (; m; m = m->m_next) {
226			for (i = 0; i < m->m_len; i++, cc--) {
227				switch (*(mtod(m, char *) + i)) {
228				case ' ':
229					if (!inspaces) {
230						spaces++;
231						inspaces = 1;
232					}
233					break;
234				case '\r':
235				case '\n':
236					DPRINT("newline");
237					goto fallout;
238				default:
239					if (spaces == 2) {
240						/* make sure we have enough data left */
241						if (cc < sizeof("HTTP/1.0") - 1) {
242							if (mbufstrncmp(m, n, i, cc, "HTTP/1.") == 1) {
243								DPRINT("mbufstrncmp ok");
244								goto readmore;
245							} else {
246								DPRINT("mbufstrncmp bad");
247								goto fallout;
248							}
249						} else if (mbufstrcmp(m, n, i, "HTTP/1.0") == 1 ||
250									mbufstrcmp(m, n, i, "HTTP/1.1") == 1) {
251								DPRINT("mbufstrcmp ok");
252								soishttpconnected(so, arg, waitflag);
253								return;
254						} else {
255							DPRINT("mbufstrcmp bad");
256							goto fallout;
257						}
258					}
259					inspaces = 0;
260					break;
261				}
262			}
263		}
264	}
265readmore:
266	DPRINT("readmore");
267	/*
268	 * if we hit here we haven't hit something
269	 * we don't understand or a newline, so try again
270	 */
271	so->so_upcall = soparsehttpvers;
272	so->so_rcv.sb_flags |= SB_UPCALL;
273	return;
274
275fallout:
276	DPRINT("fallout");
277	SIGIO_SLOCK();
278	so->so_upcall = NULL;
279	so->so_rcv.sb_flags &= ~SB_UPCALL;
280	soisconnected_locked(so);
281	SIGIO_SUNLOCK();
282	return;
283}
284
285
286#define NCHRS 3
287
288static void
289soishttpconnected(struct socket *so, void *arg, int waitflag)
290{
291	char a, b, c;
292	struct mbuf *m, *n;
293	int ccleft, copied;
294
295	DPRINT("start");
296	if ((so->so_state & SS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv))
297		goto gotit;
298
299	/*
300	 * Walk the socketbuffer and copy the last NCHRS (3) into a, b, and c
301	 * copied - how much we've copied so far
302	 * ccleft - how many bytes remaining in the socketbuffer
303	 * just loop over the mbufs subtracting from 'ccleft' until we only
304	 * have NCHRS left
305	 */
306	copied = 0;
307	ccleft = so->so_rcv.sb_cc;
308	if (ccleft < NCHRS)
309		goto readmore;
310	a = b = c = '\0';
311	for (m = so->so_rcv.sb_mb; m; m = n) {
312		n = m->m_nextpkt;
313		for (; m; m = m->m_next) {
314			ccleft -= m->m_len;
315			if (ccleft <= NCHRS) {
316				char *src;
317				int tocopy;
318
319				tocopy = (NCHRS - ccleft) - copied;
320				src = mtod(m, char *) + (m->m_len - tocopy);
321
322				while (tocopy--) {
323					switch (copied++) {
324					case 0:
325						a = *src++;
326						break;
327					case 1:
328						b = *src++;
329						break;
330					case 2:
331						c = *src++;
332						break;
333					}
334				}
335			}
336		}
337	}
338	if (c == '\n' && (b == '\n' || (b == '\r' && a == '\n'))) {
339		/* we have all request headers */
340		goto gotit;
341	}
342
343readmore:
344	so->so_upcall = soishttpconnected;
345	so->so_rcv.sb_flags |= SB_UPCALL;
346	return;
347
348gotit:
349	SIGIO_SLOCK();
350	so->so_upcall = NULL;
351	so->so_rcv.sb_flags &= ~SB_UPCALL;
352	soisconnected_locked(so);
353	SIGIO_SUNLOCK();
354	return;
355}
356