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
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD: src/sys/netinet/accf_http.c,v 1.17 2007/10/07 20:44:22 silby Exp $");
30
31 #define ACCEPT_FILTER_MOD
32
33 #include <sys/param.h>
34 #include <sys/kernel.h>
35 #include <sys/mbuf.h>
36 #include <sys/module.h>
37 #include <sys/signalvar.h>
38 #include <sys/sysctl.h>
39 #include <sys/socketvar.h>
40
41 /* check for GET/HEAD */
42 static void sohashttpget(struct socket *so, void *arg, int waitflag);
43 /* check for HTTP/1.0 or HTTP/1.1 */
44 static void soparsehttpvers(struct socket *so, void *arg, int waitflag);
45 /* check for end of HTTP/1.x request */
46 static void soishttpconnected(struct socket *so, void *arg, int waitflag);
47 /* strcmp on an mbuf chain */
48 static int mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, char *cmp);
49 /* strncmp on an mbuf chain */
50 static int mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset,
51 int max, char *cmp);
52 /* socketbuffer is full */
53 static int sbfull(struct sockbuf *sb);
54
55 static struct accept_filter accf_http_filter = {
56 "httpready",
57 sohashttpget,
58 NULL,
59 NULL
60 };
61
62 static moduledata_t accf_http_mod = {
63 "accf_http",
64 accept_filt_generic_mod_event,
65 &accf_http_filter
66 };
67
68 DECLARE_MODULE(accf_http, accf_http_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE);
69
70 static int parse_http_version = 1;
71
72 SYSCTL_NODE(_net_inet_accf, OID_AUTO, http, CTLFLAG_RW, 0,
73 "HTTP accept filter");
74 SYSCTL_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
87 static int
88 sbfull(struct sockbuf *sb)
89 {
90
91 DPRINT("sbfull, cc(%ld) >= hiwat(%ld): %d, "
92 "mbcnt(%ld) >= mbmax(%ld): %d",
93 sb->sb_cc, sb->sb_hiwat, sb->sb_cc >= sb->sb_hiwat,
94 sb->sb_mbcnt, sb->sb_mbmax, sb->sb_mbcnt >= sb->sb_mbmax);
95 return (sb->sb_cc >= sb->sb_hiwat || sb->sb_mbcnt >= sb->sb_mbmax);
96 }
97
98 /*
99 * start at mbuf m, (must provide npkt if exists)
100 * starting at offset in m compare characters in mbuf chain for 'cmp'
101 */
102 static int
103 mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, char *cmp)
104 {
105 struct mbuf *n;
106
107 for (; m != NULL; m = n) {
108 n = npkt;
109 if (npkt)
110 npkt = npkt->m_nextpkt;
111 for (; m; m = m->m_next) {
112 for (; offset < m->m_len; offset++, cmp++) {
113 if (*cmp == '\0')
114 return (1);
115 else if (*cmp != *(mtod(m, char *) + offset))
116 return (0);
117 }
118 if (*cmp == '\0')
119 return (1);
120 offset = 0;
121 }
122 }
123 return (0);
124 }
125
126 /*
127 * start at mbuf m, (must provide npkt if exists)
128 * starting at offset in m compare characters in mbuf chain for 'cmp'
129 * stop at 'max' characters
130 */
131 static int
132 mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset, int max, char *cmp)
133 {
134 struct mbuf *n;
135
136 for (; m != NULL; m = n) {
137 n = npkt;
138 if (npkt)
139 npkt = npkt->m_nextpkt;
140 for (; m; m = m->m_next) {
141 for (; offset < m->m_len; offset++, cmp++, max--) {
142 if (max == 0 || *cmp == '\0')
143 return (1);
144 else if (*cmp != *(mtod(m, char *) + offset))
145 return (0);
146 }
147 if (max == 0 || *cmp == '\0')
148 return (1);
149 offset = 0;
150 }
151 }
152 return (0);
153 }
154
155 #define STRSETUP(sptr, slen, str) \
156 do { \
157 sptr = str; \
158 slen = sizeof(str) - 1; \
159 } while(0)
160
161 static void
162 sohashttpget(struct socket *so, void *arg, int waitflag)
163 {
164
165 if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) == 0 && !sbfull(&so->so_rcv)) {
166 struct mbuf *m;
167 char *cmp;
168 int cmplen, cc;
169
170 m = so->so_rcv.sb_mb;
171 cc = so->so_rcv.sb_cc - 1;
172 if (cc < 1)
173 return;
174 switch (*mtod(m, char *)) {
175 case 'G':
176 STRSETUP(cmp, cmplen, "ET ");
177 break;
178 case 'H':
179 STRSETUP(cmp, cmplen, "EAD ");
180 break;
181 default:
182 goto fallout;
183 }
184 if (cc < cmplen) {
185 if (mbufstrncmp(m, m->m_nextpkt, 1, cc, cmp) == 1) {
186 DPRINT("short cc (%d) but mbufstrncmp ok", cc);
187 return;
188 } else {
189 DPRINT("short cc (%d) mbufstrncmp failed", cc);
190 goto fallout;
191 }
192 }
193 if (mbufstrcmp(m, m->m_nextpkt, 1, cmp) == 1) {
194 DPRINT("mbufstrcmp ok");
195 if (parse_http_version == 0)
196 soishttpconnected(so, arg, waitflag);
197 else
198 soparsehttpvers(so, arg, waitflag);
199 return;
200 }
201 DPRINT("mbufstrcmp bad");
202 }
203
204 fallout:
205 DPRINT("fallout");
206 so->so_upcall = NULL;
207 so->so_rcv.sb_flags &= ~SB_UPCALL;
208 soisconnected(so);
209 return;
210 }
211
212 static void
213 soparsehttpvers(struct socket *so, void *arg, int waitflag)
214 {
215 struct mbuf *m, *n;
216 int i, cc, spaces, inspaces;
217
218 if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv))
219 goto fallout;
220
221 m = so->so_rcv.sb_mb;
222 cc = so->so_rcv.sb_cc;
223 inspaces = spaces = 0;
224 for (m = so->so_rcv.sb_mb; m; m = n) {
225 n = m->m_nextpkt;
226 for (; m; m = m->m_next) {
227 for (i = 0; i < m->m_len; i++, cc--) {
228 switch (*(mtod(m, char *) + i)) {
229 case ' ':
230 /* tabs? '\t' */
231 if (!inspaces) {
232 spaces++;
233 inspaces = 1;
234 }
235 break;
236 case '\r':
237 case '\n':
238 DPRINT("newline");
239 goto fallout;
240 default:
241 if (spaces != 2) {
242 inspaces = 0;
243 break;
244 }
245
246 /*
247 * if we don't have enough characters
248 * left (cc < sizeof("HTTP/1.0") - 1)
249 * then see if the remaining ones
250 * are a request we can parse.
251 */
252 if (cc < sizeof("HTTP/1.0") - 1) {
253 if (mbufstrncmp(m, n, i, cc,
254 "HTTP/1.") == 1) {
255 DPRINT("ok");
256 goto readmore;
257 } else {
258 DPRINT("bad");
259 goto fallout;
260 }
261 } else if (
262 mbufstrcmp(m, n, i, "HTTP/1.0") ||
263 mbufstrcmp(m, n, i, "HTTP/1.1")) {
264 DPRINT("ok");
265 soishttpconnected(so,
266 arg, waitflag);
267 return;
268 } else {
269 DPRINT("bad");
270 goto fallout;
271 }
272 }
273 }
274 }
275 }
276 readmore:
277 DPRINT("readmore");
278 /*
279 * if we hit here we haven't hit something
280 * we don't understand or a newline, so try again
281 */
282 so->so_upcall = soparsehttpvers;
283 so->so_rcv.sb_flags |= SB_UPCALL;
284 return;
285
286 fallout:
287 DPRINT("fallout");
288 so->so_upcall = NULL;
289 so->so_rcv.sb_flags &= ~SB_UPCALL;
290 soisconnected(so);
291 return;
292 }
293
294
295 #define NCHRS 3
296
297 static void
298 soishttpconnected(struct socket *so, void *arg, int waitflag)
299 {
300 char a, b, c;
301 struct mbuf *m, *n;
302 int ccleft, copied;
303
304 DPRINT("start");
305 if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv))
306 goto gotit;
307
308 /*
309 * Walk the socketbuffer and copy the last NCHRS (3) into a, b, and c
310 * copied - how much we've copied so far
311 * ccleft - how many bytes remaining in the socketbuffer
312 * just loop over the mbufs subtracting from 'ccleft' until we only
313 * have NCHRS left
314 */
315 copied = 0;
316 ccleft = so->so_rcv.sb_cc;
317 if (ccleft < NCHRS)
318 goto readmore;
319 a = b = c = '\0';
320 for (m = so->so_rcv.sb_mb; m; m = n) {
321 n = m->m_nextpkt;
322 for (; m; m = m->m_next) {
323 ccleft -= m->m_len;
324 if (ccleft <= NCHRS) {
325 char *src;
326 int tocopy;
327
328 tocopy = (NCHRS - ccleft) - copied;
329 src = mtod(m, char *) + (m->m_len - tocopy);
330
331 while (tocopy--) {
332 switch (copied++) {
333 case 0:
334 a = *src++;
335 break;
336 case 1:
337 b = *src++;
338 break;
339 case 2:
340 c = *src++;
341 break;
342 }
343 }
344 }
345 }
346 }
347 if (c == '\n' && (b == '\n' || (b == '\r' && a == '\n'))) {
348 /* we have all request headers */
349 goto gotit;
350 }
351
352 readmore:
353 so->so_upcall = soishttpconnected;
354 so->so_rcv.sb_flags |= SB_UPCALL;
355 return;
356
357 gotit:
358 so->so_upcall = NULL;
359 so->so_rcv.sb_flags &= ~SB_UPCALL;
360 soisconnected(so);
361 return;
362 }
363
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