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/5.0/sys/netinet/accf_http.c 98385 2002-06-18 07:42:02Z tanimura $
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/signalvar.h>
36 #include <sys/sysctl.h>
37 #include <sys/socketvar.h>
38
39 /* check for GET/HEAD */
40 static void sohashttpget(struct socket *so, void *arg, int waitflag);
41 /* check for HTTP/1.0 or HTTP/1.1 */
42 static void soparsehttpvers(struct socket *so, void *arg, int waitflag);
43 /* check for end of HTTP/1.x request */
44 static void soishttpconnected(struct socket *so, void *arg, int waitflag);
45 /* strcmp on an mbuf chain */
46 static int mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, char *cmp);
47 /* strncmp on an mbuf chain */
48 static int mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset,
49 int max, char *cmp);
50 /* socketbuffer is full */
51 static int sbfull(struct sockbuf *sb);
52
53 static struct accept_filter accf_http_filter = {
54 "httpready",
55 sohashttpget,
56 NULL,
57 NULL
58 };
59
60 static moduledata_t accf_http_mod = {
61 "accf_http",
62 accept_filt_generic_mod_event,
63 &accf_http_filter
64 };
65
66 DECLARE_MODULE(accf_http, accf_http_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE);
67
68 static int parse_http_version = 1;
69
70 SYSCTL_NODE(_net_inet_accf, OID_AUTO, http, CTLFLAG_RW, 0,
71 "HTTP accept filter");
72 SYSCTL_INT(_net_inet_accf_http, OID_AUTO, parsehttpversion, CTLFLAG_RW,
73 &parse_http_version, 1,
74 "Parse http version so that non 1.x requests work");
75
76 #ifdef ACCF_HTTP_DEBUG
77 #define DPRINT(fmt, args...) \
78 do { \
79 printf("%s:%d: " fmt "\n", __func__, __LINE__, ##args); \
80 } while (0)
81 #else
82 #define DPRINT(fmt, args...)
83 #endif
84
85 static int
86 sbfull(struct sockbuf *sb)
87 {
88
89 DPRINT("sbfull, cc(%ld) >= hiwat(%ld): %d, "
90 "mbcnt(%ld) >= mbmax(%ld): %d",
91 sb->sb_cc, sb->sb_hiwat, sb->sb_cc >= sb->sb_hiwat,
92 sb->sb_mbcnt, sb->sb_mbmax, sb->sb_mbcnt >= sb->sb_mbmax);
93 return (sb->sb_cc >= sb->sb_hiwat || sb->sb_mbcnt >= sb->sb_mbmax);
94 }
95
96 /*
97 * start at mbuf m, (must provide npkt if exists)
98 * starting at offset in m compare characters in mbuf chain for 'cmp'
99 */
100 static int
101 mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, char *cmp)
102 {
103 struct mbuf *n;
104
105 for (; m != NULL; m = n) {
106 n = npkt;
107 if (npkt)
108 npkt = npkt->m_nextpkt;
109 for (; m; m = m->m_next) {
110 for (; offset < m->m_len; offset++, cmp++) {
111 if (*cmp == '\0')
112 return (1);
113 else if (*cmp != *(mtod(m, char *) + offset))
114 return (0);
115 }
116 if (*cmp == '\0')
117 return (1);
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 */
129 static int
130 mbufstrncmp(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 if (max == 0 || *cmp == '\0')
146 return (1);
147 offset = 0;
148 }
149 }
150 return (0);
151 }
152
153 #define STRSETUP(sptr, slen, str) \
154 do { \
155 sptr = str; \
156 slen = sizeof(str) - 1; \
157 } while(0)
158
159 static void
160 sohashttpget(struct socket *so, void *arg, int waitflag)
161 {
162
163 if ((so->so_state & SS_CANTRCVMORE) == 0 && !sbfull(&so->so_rcv)) {
164 struct mbuf *m;
165 char *cmp;
166 int cmplen, cc;
167
168 m = so->so_rcv.sb_mb;
169 cc = so->so_rcv.sb_cc - 1;
170 if (cc < 1)
171 return;
172 switch (*mtod(m, char *)) {
173 case 'G':
174 STRSETUP(cmp, cmplen, "ET ");
175 break;
176 case 'H':
177 STRSETUP(cmp, cmplen, "EAD ");
178 break;
179 default:
180 goto fallout;
181 }
182 if (cc < cmplen) {
183 if (mbufstrncmp(m, m->m_nextpkt, 1, cc, cmp) == 1) {
184 DPRINT("short cc (%d) but mbufstrncmp ok", cc);
185 return;
186 } else {
187 DPRINT("short cc (%d) mbufstrncmp failed", cc);
188 goto fallout;
189 }
190 }
191 if (mbufstrcmp(m, m->m_nextpkt, 1, cmp) == 1) {
192 DPRINT("mbufstrcmp ok");
193 if (parse_http_version == 0)
194 soishttpconnected(so, arg, waitflag);
195 else
196 soparsehttpvers(so, arg, waitflag);
197 return;
198 }
199 DPRINT("mbufstrcmp bad");
200 }
201
202 fallout:
203 DPRINT("fallout");
204 so->so_upcall = NULL;
205 so->so_rcv.sb_flags &= ~SB_UPCALL;
206 soisconnected(so);
207 return;
208 }
209
210 static void
211 soparsehttpvers(struct socket *so, void *arg, int waitflag)
212 {
213 struct mbuf *m, *n;
214 int i, cc, spaces, inspaces;
215
216 if ((so->so_state & SS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv))
217 goto fallout;
218
219 m = so->so_rcv.sb_mb;
220 cc = so->so_rcv.sb_cc;
221 inspaces = spaces = 0;
222 for (m = so->so_rcv.sb_mb; m; m = n) {
223 n = m->m_nextpkt;
224 for (; m; m = m->m_next) {
225 for (i = 0; i < m->m_len; i++, cc--) {
226 switch (*(mtod(m, char *) + i)) {
227 case ' ':
228 /* tabs? '\t' */
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 inspaces = 0;
241 break;
242 }
243
244 /*
245 * if we don't have enough characters
246 * left (cc < sizeof("HTTP/1.0") - 1)
247 * then see if the remaining ones
248 * are a request we can parse.
249 */
250 if (cc < sizeof("HTTP/1.0") - 1) {
251 if (mbufstrncmp(m, n, i, cc,
252 "HTTP/1.") == 1) {
253 DPRINT("ok");
254 goto readmore;
255 } else {
256 DPRINT("bad");
257 goto fallout;
258 }
259 } else if (
260 mbufstrcmp(m, n, i, "HTTP/1.0") ||
261 mbufstrcmp(m, n, i, "HTTP/1.1")) {
262 DPRINT("ok");
263 soishttpconnected(so,
264 arg, waitflag);
265 return;
266 } else {
267 DPRINT("bad");
268 goto fallout;
269 }
270 }
271 }
272 }
273 }
274 readmore:
275 DPRINT("readmore");
276 /*
277 * if we hit here we haven't hit something
278 * we don't understand or a newline, so try again
279 */
280 so->so_upcall = soparsehttpvers;
281 so->so_rcv.sb_flags |= SB_UPCALL;
282 return;
283
284 fallout:
285 DPRINT("fallout");
286 so->so_upcall = NULL;
287 so->so_rcv.sb_flags &= ~SB_UPCALL;
288 soisconnected(so);
289 return;
290 }
291
292
293 #define NCHRS 3
294
295 static void
296 soishttpconnected(struct socket *so, void *arg, int waitflag)
297 {
298 char a, b, c;
299 struct mbuf *m, *n;
300 int ccleft, copied;
301
302 DPRINT("start");
303 if ((so->so_state & SS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv))
304 goto gotit;
305
306 /*
307 * Walk the socketbuffer and copy the last NCHRS (3) into a, b, and c
308 * copied - how much we've copied so far
309 * ccleft - how many bytes remaining in the socketbuffer
310 * just loop over the mbufs subtracting from 'ccleft' until we only
311 * have NCHRS left
312 */
313 copied = 0;
314 ccleft = so->so_rcv.sb_cc;
315 if (ccleft < NCHRS)
316 goto readmore;
317 a = b = c = '\0';
318 for (m = so->so_rcv.sb_mb; m; m = n) {
319 n = m->m_nextpkt;
320 for (; m; m = m->m_next) {
321 ccleft -= m->m_len;
322 if (ccleft <= NCHRS) {
323 char *src;
324 int tocopy;
325
326 tocopy = (NCHRS - ccleft) - copied;
327 src = mtod(m, char *) + (m->m_len - tocopy);
328
329 while (tocopy--) {
330 switch (copied++) {
331 case 0:
332 a = *src++;
333 break;
334 case 1:
335 b = *src++;
336 break;
337 case 2:
338 c = *src++;
339 break;
340 }
341 }
342 }
343 }
344 }
345 if (c == '\n' && (b == '\n' || (b == '\r' && a == '\n'))) {
346 /* we have all request headers */
347 goto gotit;
348 }
349
350 readmore:
351 so->so_upcall = soishttpconnected;
352 so->so_rcv.sb_flags |= SB_UPCALL;
353 return;
354
355 gotit:
356 so->so_upcall = NULL;
357 so->so_rcv.sb_flags &= ~SB_UPCALL;
358 soisconnected(so);
359 return;
360 }
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