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: releng/6.3/sys/netinet/accf_http.c 139823 2005-01-07 01:45:51Z imp $
28 */
29
30 #define ACCEPT_FILTER_MOD
31
32 #include <sys/param.h>
33 #include <sys/kernel.h>
34 #include <sys/mbuf.h>
35 #include <sys/module.h>
36 #include <sys/signalvar.h>
37 #include <sys/sysctl.h>
38 #include <sys/socketvar.h>
39
40 /* check for GET/HEAD */
41 static void sohashttpget(struct socket *so, void *arg, int waitflag);
42 /* check for HTTP/1.0 or HTTP/1.1 */
43 static void soparsehttpvers(struct socket *so, void *arg, int waitflag);
44 /* check for end of HTTP/1.x request */
45 static void soishttpconnected(struct socket *so, void *arg, int waitflag);
46 /* strcmp on an mbuf chain */
47 static int mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, char *cmp);
48 /* strncmp on an mbuf chain */
49 static int mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset,
50 int max, char *cmp);
51 /* socketbuffer is full */
52 static int sbfull(struct sockbuf *sb);
53
54 static struct accept_filter accf_http_filter = {
55 "httpready",
56 sohashttpget,
57 NULL,
58 NULL
59 };
60
61 static moduledata_t accf_http_mod = {
62 "accf_http",
63 accept_filt_generic_mod_event,
64 &accf_http_filter
65 };
66
67 DECLARE_MODULE(accf_http, accf_http_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE);
68
69 static int parse_http_version = 1;
70
71 SYSCTL_NODE(_net_inet_accf, OID_AUTO, http, CTLFLAG_RW, 0,
72 "HTTP accept filter");
73 SYSCTL_INT(_net_inet_accf_http, OID_AUTO, parsehttpversion, CTLFLAG_RW,
74 &parse_http_version, 1,
75 "Parse http version so that non 1.x requests work");
76
77 #ifdef ACCF_HTTP_DEBUG
78 #define DPRINT(fmt, args...) \
79 do { \
80 printf("%s:%d: " fmt "\n", __func__, __LINE__, ##args); \
81 } while (0)
82 #else
83 #define DPRINT(fmt, args...)
84 #endif
85
86 static int
87 sbfull(struct sockbuf *sb)
88 {
89
90 DPRINT("sbfull, cc(%ld) >= hiwat(%ld): %d, "
91 "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 */
101 static int
102 mbufstrcmp(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 if (*cmp == '\0')
118 return (1);
119 offset = 0;
120 }
121 }
122 return (0);
123 }
124
125 /*
126 * start at mbuf m, (must provide npkt if exists)
127 * starting at offset in m compare characters in mbuf chain for 'cmp'
128 * stop at 'max' characters
129 */
130 static int
131 mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset, int max, char *cmp)
132 {
133 struct mbuf *n;
134
135 for (; m != NULL; m = n) {
136 n = npkt;
137 if (npkt)
138 npkt = npkt->m_nextpkt;
139 for (; m; m = m->m_next) {
140 for (; offset < m->m_len; offset++, cmp++, max--) {
141 if (max == 0 || *cmp == '\0')
142 return (1);
143 else if (*cmp != *(mtod(m, char *) + offset))
144 return (0);
145 }
146 if (max == 0 || *cmp == '\0')
147 return (1);
148 offset = 0;
149 }
150 }
151 return (0);
152 }
153
154 #define STRSETUP(sptr, slen, str) \
155 do { \
156 sptr = str; \
157 slen = sizeof(str) - 1; \
158 } while(0)
159
160 static void
161 sohashttpget(struct socket *so, void *arg, int waitflag)
162 {
163
164 if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) == 0 && !sbfull(&so->so_rcv)) {
165 struct mbuf *m;
166 char *cmp;
167 int cmplen, cc;
168
169 m = so->so_rcv.sb_mb;
170 cc = so->so_rcv.sb_cc - 1;
171 if (cc < 1)
172 return;
173 switch (*mtod(m, char *)) {
174 case 'G':
175 STRSETUP(cmp, cmplen, "ET ");
176 break;
177 case 'H':
178 STRSETUP(cmp, cmplen, "EAD ");
179 break;
180 default:
181 goto fallout;
182 }
183 if (cc < cmplen) {
184 if (mbufstrncmp(m, m->m_nextpkt, 1, cc, cmp) == 1) {
185 DPRINT("short cc (%d) but mbufstrncmp ok", cc);
186 return;
187 } else {
188 DPRINT("short cc (%d) mbufstrncmp failed", cc);
189 goto fallout;
190 }
191 }
192 if (mbufstrcmp(m, m->m_nextpkt, 1, cmp) == 1) {
193 DPRINT("mbufstrcmp ok");
194 if (parse_http_version == 0)
195 soishttpconnected(so, arg, waitflag);
196 else
197 soparsehttpvers(so, arg, waitflag);
198 return;
199 }
200 DPRINT("mbufstrcmp bad");
201 }
202
203 fallout:
204 DPRINT("fallout");
205 so->so_upcall = NULL;
206 so->so_rcv.sb_flags &= ~SB_UPCALL;
207 soisconnected(so);
208 return;
209 }
210
211 static void
212 soparsehttpvers(struct socket *so, void *arg, int waitflag)
213 {
214 struct mbuf *m, *n;
215 int i, cc, spaces, inspaces;
216
217 if ((so->so_rcv.sb_state & SBS_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 /* tabs? '\t' */
230 if (!inspaces) {
231 spaces++;
232 inspaces = 1;
233 }
234 break;
235 case '\r':
236 case '\n':
237 DPRINT("newline");
238 goto fallout;
239 default:
240 if (spaces != 2) {
241 inspaces = 0;
242 break;
243 }
244
245 /*
246 * if we don't have enough characters
247 * left (cc < sizeof("HTTP/1.0") - 1)
248 * then see if the remaining ones
249 * are a request we can parse.
250 */
251 if (cc < sizeof("HTTP/1.0") - 1) {
252 if (mbufstrncmp(m, n, i, cc,
253 "HTTP/1.") == 1) {
254 DPRINT("ok");
255 goto readmore;
256 } else {
257 DPRINT("bad");
258 goto fallout;
259 }
260 } else if (
261 mbufstrcmp(m, n, i, "HTTP/1.0") ||
262 mbufstrcmp(m, n, i, "HTTP/1.1")) {
263 DPRINT("ok");
264 soishttpconnected(so,
265 arg, waitflag);
266 return;
267 } else {
268 DPRINT("bad");
269 goto fallout;
270 }
271 }
272 }
273 }
274 }
275 readmore:
276 DPRINT("readmore");
277 /*
278 * if we hit here we haven't hit something
279 * we don't understand or a newline, so try again
280 */
281 so->so_upcall = soparsehttpvers;
282 so->so_rcv.sb_flags |= SB_UPCALL;
283 return;
284
285 fallout:
286 DPRINT("fallout");
287 so->so_upcall = NULL;
288 so->so_rcv.sb_flags &= ~SB_UPCALL;
289 soisconnected(so);
290 return;
291 }
292
293
294 #define NCHRS 3
295
296 static void
297 soishttpconnected(struct socket *so, void *arg, int waitflag)
298 {
299 char a, b, c;
300 struct mbuf *m, *n;
301 int ccleft, copied;
302
303 DPRINT("start");
304 if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv))
305 goto gotit;
306
307 /*
308 * Walk the socketbuffer and copy the last NCHRS (3) into a, b, and c
309 * copied - how much we've copied so far
310 * ccleft - how many bytes remaining in the socketbuffer
311 * just loop over the mbufs subtracting from 'ccleft' until we only
312 * have NCHRS left
313 */
314 copied = 0;
315 ccleft = so->so_rcv.sb_cc;
316 if (ccleft < NCHRS)
317 goto readmore;
318 a = b = c = '\0';
319 for (m = so->so_rcv.sb_mb; m; m = n) {
320 n = m->m_nextpkt;
321 for (; m; m = m->m_next) {
322 ccleft -= m->m_len;
323 if (ccleft <= NCHRS) {
324 char *src;
325 int tocopy;
326
327 tocopy = (NCHRS - ccleft) - copied;
328 src = mtod(m, char *) + (m->m_len - tocopy);
329
330 while (tocopy--) {
331 switch (copied++) {
332 case 0:
333 a = *src++;
334 break;
335 case 1:
336 b = *src++;
337 break;
338 case 2:
339 c = *src++;
340 break;
341 }
342 }
343 }
344 }
345 }
346 if (c == '\n' && (b == '\n' || (b == '\r' && a == '\n'))) {
347 /* we have all request headers */
348 goto gotit;
349 }
350
351 readmore:
352 so->so_upcall = soishttpconnected;
353 so->so_rcv.sb_flags |= SB_UPCALL;
354 return;
355
356 gotit:
357 so->so_upcall = NULL;
358 so->so_rcv.sb_flags &= ~SB_UPCALL;
359 soisconnected(so);
360 return;
361 }
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