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("$FreeBSD$");
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 int sohashttpget(struct socket *so, void *arg, int waitflag);
43 /* check for HTTP/1.0 or HTTP/1.1 */
44 static int soparsehttpvers(struct socket *so, void *arg, int waitflag);
45 /* check for end of HTTP/1.x request */
46 static int 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 static 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 (sbused(sb) >= 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 int
162 sohashttpget(struct socket *so, void *arg, int waitflag)
163 {
164
165 if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) == 0 &&
166 !sbfull(&so->so_rcv)) {
167 struct mbuf *m;
168 char *cmp;
169 int cmplen, cc;
170
171 m = so->so_rcv.sb_mb;
172 cc = sbavail(&so->so_rcv) - 1;
173 if (cc < 1)
174 return (SU_OK);
175 switch (*mtod(m, char *)) {
176 case 'G':
177 STRSETUP(cmp, cmplen, "ET ");
178 break;
179 case 'H':
180 STRSETUP(cmp, cmplen, "EAD ");
181 break;
182 default:
183 goto fallout;
184 }
185 if (cc < cmplen) {
186 if (mbufstrncmp(m, m->m_nextpkt, 1, cc, cmp) == 1) {
187 DPRINT("short cc (%d) but mbufstrncmp ok", cc);
188 return (SU_OK);
189 } else {
190 DPRINT("short cc (%d) mbufstrncmp failed", cc);
191 goto fallout;
192 }
193 }
194 if (mbufstrcmp(m, m->m_nextpkt, 1, cmp) == 1) {
195 DPRINT("mbufstrcmp ok");
196 if (parse_http_version == 0)
197 return (soishttpconnected(so, arg, waitflag));
198 else
199 return (soparsehttpvers(so, arg, waitflag));
200 }
201 DPRINT("mbufstrcmp bad");
202 }
203
204 fallout:
205 DPRINT("fallout");
206 return (SU_ISCONNECTED);
207 }
208
209 static int
210 soparsehttpvers(struct socket *so, void *arg, int waitflag)
211 {
212 struct mbuf *m, *n;
213 int i, cc, spaces, inspaces;
214
215 if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv))
216 goto fallout;
217
218 m = so->so_rcv.sb_mb;
219 cc = sbavail(&so->so_rcv);
220 inspaces = spaces = 0;
221 for (m = so->so_rcv.sb_mb; m; m = n) {
222 n = m->m_nextpkt;
223 for (; m; m = m->m_next) {
224 for (i = 0; i < m->m_len; i++, cc--) {
225 switch (*(mtod(m, char *) + i)) {
226 case ' ':
227 /* tabs? '\t' */
228 if (!inspaces) {
229 spaces++;
230 inspaces = 1;
231 }
232 break;
233 case '\r':
234 case '\n':
235 DPRINT("newline");
236 goto fallout;
237 default:
238 if (spaces != 2) {
239 inspaces = 0;
240 break;
241 }
242
243 /*
244 * if we don't have enough characters
245 * left (cc < sizeof("HTTP/1.0") - 1)
246 * then see if the remaining ones
247 * are a request we can parse.
248 */
249 if (cc < sizeof("HTTP/1.0") - 1) {
250 if (mbufstrncmp(m, n, i, cc,
251 "HTTP/1.") == 1) {
252 DPRINT("ok");
253 goto readmore;
254 } else {
255 DPRINT("bad");
256 goto fallout;
257 }
258 } else if (
259 mbufstrcmp(m, n, i, "HTTP/1.0") ||
260 mbufstrcmp(m, n, i, "HTTP/1.1")) {
261 DPRINT("ok");
262 return (soishttpconnected(so,
263 arg, waitflag));
264 } else {
265 DPRINT("bad");
266 goto fallout;
267 }
268 }
269 }
270 }
271 }
272 readmore:
273 DPRINT("readmore");
274 /*
275 * if we hit here we haven't hit something
276 * we don't understand or a newline, so try again
277 */
278 soupcall_set(so, SO_RCV, soparsehttpvers, arg);
279 return (SU_OK);
280
281 fallout:
282 DPRINT("fallout");
283 return (SU_ISCONNECTED);
284 }
285
286
287 #define NCHRS 3
288
289 static int
290 soishttpconnected(struct socket *so, void *arg, int waitflag)
291 {
292 char a, b, c;
293 struct mbuf *m, *n;
294 int ccleft, copied;
295
296 DPRINT("start");
297 if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv))
298 goto gotit;
299
300 /*
301 * Walk the socketbuffer and copy the last NCHRS (3) into a, b, and c
302 * copied - how much we've copied so far
303 * ccleft - how many bytes remaining in the socketbuffer
304 * just loop over the mbufs subtracting from 'ccleft' until we only
305 * have NCHRS left
306 */
307 copied = 0;
308 ccleft = sbavail(&so->so_rcv);
309 if (ccleft < NCHRS)
310 goto readmore;
311 a = b = c = '\0';
312 for (m = so->so_rcv.sb_mb; m; m = n) {
313 n = m->m_nextpkt;
314 for (; m; m = m->m_next) {
315 ccleft -= m->m_len;
316 if (ccleft <= NCHRS) {
317 char *src;
318 int tocopy;
319
320 tocopy = (NCHRS - ccleft) - copied;
321 src = mtod(m, char *) + (m->m_len - tocopy);
322
323 while (tocopy--) {
324 switch (copied++) {
325 case 0:
326 a = *src++;
327 break;
328 case 1:
329 b = *src++;
330 break;
331 case 2:
332 c = *src++;
333 break;
334 }
335 }
336 }
337 }
338 }
339 if (c == '\n' && (b == '\n' || (b == '\r' && a == '\n'))) {
340 /* we have all request headers */
341 goto gotit;
342 }
343
344 readmore:
345 soupcall_set(so, SO_RCV, soishttpconnected, arg);
346 return (SU_OK);
347
348 gotit:
349 return (SU_ISCONNECTED);
350 }
Cache object: 6bf71df593ea05818d0bf9e876c62ee8
|