1/* $NetBSD: accf_http.c,v 1.9 2015/08/20 14:40:19 christos Exp $ */
2
3/*-
4 * Copyright (c) 2000 Paycounter, Inc.
5 * Author: Alfred Perlstein <alfred@paycounter.com>, <alfred@FreeBSD.org>
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#include <sys/cdefs.h>
31__KERNEL_RCSID(0, "$NetBSD: accf_http.c,v 1.9 2015/08/20 14:40:19 christos Exp $");
32
33#define ACCEPT_FILTER_MOD
34
35#include <sys/param.h>
36#include <sys/kernel.h>
37#include <sys/mbuf.h>
38#include <sys/module.h>
39#include <sys/signalvar.h>
40#include <sys/sysctl.h>
41#include <sys/socket.h>
42#include <sys/socketvar.h>
43
44#include <netinet/accept_filter.h>
45
46#include "ioconf.h"
47
48MODULE(MODULE_CLASS_MISC, accf_httpready, NULL);
49
50/* check for GET/HEAD */
51static void sohashttpget(struct socket *so, void *arg, int events, int waitflag);
52/* check for HTTP/1.0 or HTTP/1.1 */
53static void soparsehttpvers(struct socket *so, void *arg, int events, int waitflag);
54/* check for end of HTTP/1.x request */
55static void soishttpconnected(struct socket *so, void *arg, int events, int waitflag);
56/* strcmp on an mbuf chain */
57static int mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, const char *cmp);
58/* strncmp on an mbuf chain */
59static int mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset,
60 int len, const char *cmp);
61/* socketbuffer is full */
62static int sbfull(struct sockbuf *sb);
63
64static struct accept_filter accf_http_filter = {
65 .accf_name = "httpready",
66 .accf_callback = sohashttpget,
67};
68
69/*
70 * Names of HTTP Accept filter sysctl objects
71 */
72
73#define ACCFCTL_PARSEVER 1 /* Parse HTTP version */
74
75static int parse_http_version = 1;
76
77void
78accf_httpattach(int junk)
79{
80
81}
82
83static int
84accf_httpready_modcmd(modcmd_t cmd, void *arg)
85{
86 static struct sysctllog *clog;
87 int error;
88
89 switch (cmd) {
90 case MODULE_CMD_INIT:
91 error = accept_filt_add(&accf_http_filter);
92 if (error != 0) {
93 return error;
94 }
95 sysctl_createv(&clog, 0, NULL, NULL,
96 CTLFLAG_PERMANENT,
97 CTLTYPE_NODE, "inet", NULL,
98 NULL, 0, NULL, 0,
99 CTL_NET, PF_INET, CTL_EOL);
100 sysctl_createv(&clog, 0, NULL, NULL,
101 CTLFLAG_PERMANENT,
102 CTLTYPE_NODE, "accf", NULL,
103 NULL, 0, NULL, 0,
104 CTL_NET, PF_INET, SO_ACCEPTFILTER, CTL_EOL);
105 sysctl_createv(&clog, 0, NULL, NULL,
106 CTLFLAG_PERMANENT,
107 CTLTYPE_NODE, "http",
108 SYSCTL_DESCR("HTTP accept filter"),
109 NULL, 0, NULL, 0,
110 CTL_NET, PF_INET, SO_ACCEPTFILTER, ACCF_HTTP, CTL_EOL);
111 sysctl_createv(&clog, 0, NULL, NULL,
112 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
113 CTLTYPE_INT, "parsehttpversion",
114 SYSCTL_DESCR("Parse http version so that non "
115 "1.x requests work"),
116 NULL, 0, &parse_http_version, 0,
117 CTL_NET, PF_INET, SO_ACCEPTFILTER, ACCF_HTTP,
118 ACCFCTL_PARSEVER, CTL_EOL);
119 return 0;
120
121 case MODULE_CMD_FINI:
122 error = accept_filt_del(&accf_http_filter);
123 if (error != 0) {
124 return error;
125 }
126 sysctl_teardown(&clog);
127 return 0;
128
129 default:
130 return ENOTTY;
131 }
132}
133
134#ifdef ACCF_HTTP_DEBUG
135#define DPRINT(fmt, args...) \
136 do { \
137 printf("%s:%d: " fmt "\n", __func__, __LINE__, ##args); \
138 } while (0)
139#else
140#define DPRINT(fmt, args...)
141#endif
142
143static int
144sbfull(struct sockbuf *sb)
145{
146
147 DPRINT("sbfull, cc(%ld) >= hiwat(%ld): %d, "
148 "mbcnt(%ld) >= mbmax(%ld): %d",
149 sb->sb_cc, sb->sb_hiwat, sb->sb_cc >= sb->sb_hiwat,
150 sb->sb_mbcnt, sb->sb_mbmax, sb->sb_mbcnt >= sb->sb_mbmax);
151 return (sb->sb_cc >= sb->sb_hiwat || sb->sb_mbcnt >= sb->sb_mbmax);
152}
153
154/*
155 * start at mbuf m, (must provide npkt if exists)
156 * starting at offset in m compare characters in mbuf chain for 'cmp'
157 */
158static int
159mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, const char *cmp)
160{
161 struct mbuf *n;
162
163 for (; m != NULL; m = n) {
164 n = npkt;
165 if (npkt)
166 npkt = npkt->m_nextpkt;
167 for (; m; m = m->m_next) {
168 for (; offset < m->m_len; offset++, cmp++) {
169 if (*cmp == '\0')
170 return (1);
171 else if (*cmp != *(mtod(m, char *) + offset))
172 return (0);
173 }
174 if (*cmp == '\0')
175 return (1);
176 offset = 0;
177 }
178 }
179 return (0);
180}
181
182/*
183 * start at mbuf m, (must provide npkt if exists)
184 * starting at offset in m compare characters in mbuf chain for 'cmp'
185 * stop at 'max' characters
186 */
187static int
188mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset, int len, const char *cmp)
189{
190 struct mbuf *n;
191
192 for (; m != NULL; m = n) {
193 n = npkt;
194 if (npkt)
195 npkt = npkt->m_nextpkt;
196 for (; m; m = m->m_next) {
197 for (; offset < m->m_len; offset++, cmp++, len--) {
198 if (len == 0 || *cmp == '\0')
199 return (1);
200 else if (*cmp != *(mtod(m, char *) + offset))
201 return (0);
202 }
203 if (len == 0 || *cmp == '\0')
204 return (1);
205 offset = 0;
206 }
207 }
208 return (0);
209}
210
211#define STRSETUP(sptr, slen, str) \
212 do { \
213 sptr = str; \
214 slen = sizeof(str) - 1; \
215 } while(0)
216
217static void
218sohashttpget(struct socket *so, void *arg, int events, int waitflag)
219{
220
221 if ((so->so_state & SS_CANTRCVMORE) == 0 && !sbfull(&so->so_rcv)) {
222 struct mbuf *m;
223 const char *cmp;
224 int cmplen, cc;
225
226 m = so->so_rcv.sb_mb;
227 cc = so->so_rcv.sb_cc - 1;
228 if (cc < 1)
229 return;
230 switch (*mtod(m, char *)) {
231 case 'G':
232 STRSETUP(cmp, cmplen, "ET ");
233 break;
234 case 'H':
235 STRSETUP(cmp, cmplen, "EAD ");
236 break;
237 default:
238 goto fallout;
239 }
240 if (cc < cmplen) {
241 if (mbufstrncmp(m, m->m_nextpkt, 1, cc, cmp) == 1) {
242 DPRINT("short cc (%d) but mbufstrncmp ok", cc);
243 return;
244 } else {
245 DPRINT("short cc (%d) mbufstrncmp failed", cc);
246 goto fallout;
247 }
248 }
249 if (mbufstrcmp(m, m->m_nextpkt, 1, cmp) == 1) {
250 DPRINT("mbufstrcmp ok");
251 if (parse_http_version == 0)
252 soishttpconnected(so, arg, events, waitflag);
253 else
254 soparsehttpvers(so, arg, events, waitflag);
255 return;
256 }
257 DPRINT("mbufstrcmp bad");
258 }
259
260fallout:
261 DPRINT("fallout");
262 so->so_upcall = NULL;
263 so->so_rcv.sb_flags &= ~SB_UPCALL;
264 soisconnected(so);
265 return;
266}
267
268static void
269soparsehttpvers(struct socket *so, void *arg, int events, int waitflag)
270{
271 struct mbuf *m, *n;
272 int i, cc, spaces, inspaces;
273
274 if ((so->so_state & SS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv))
275 goto fallout;
276
277 m = so->so_rcv.sb_mb;
278 cc = so->so_rcv.sb_cc;
279 inspaces = spaces = 0;
280 for (m = so->so_rcv.sb_mb; m; m = n) {
281 n = m->m_nextpkt;
282 for (; m; m = m->m_next) {
283 for (i = 0; i < m->m_len; i++, cc--) {
284 switch (*(mtod(m, char *) + i)) {
285 case ' ':
286 /* tabs? '\t' */
287 if (!inspaces) {
288 spaces++;
289 inspaces = 1;
290 }
291 break;
292 case '\r':
293 case '\n':
294 DPRINT("newline");
295 goto fallout;
296 default:
297 if (spaces != 2) {
298 inspaces = 0;
299 break;
300 }
301
302 /*
303 * if we don't have enough characters
304 * left (cc < sizeof("HTTP/1.0") - 1)
305 * then see if the remaining ones
306 * are a request we can parse.
307 */
308 if (cc < sizeof("HTTP/1.0") - 1) {
309 if (mbufstrncmp(m, n, i, cc,
310 "HTTP/1.") == 1) {
311 DPRINT("ok");
312 goto readmore;
313 } else {
314 DPRINT("bad");
315 goto fallout;
316 }
317 } else if (
318 mbufstrcmp(m, n, i, "HTTP/1.0") ||
319 mbufstrcmp(m, n, i, "HTTP/1.1")) {
320 DPRINT("ok");
321 soishttpconnected(so,
322 arg, events, waitflag);
323 return;
324 } else {
325 DPRINT("bad");
326 goto fallout;
327 }
328 }
329 }
330 }
331 }
332readmore:
333 DPRINT("readmore");
334 /*
335 * if we hit here we haven't hit something
336 * we don't understand or a newline, so try again
337 */
338 so->so_upcall = soparsehttpvers;
339 so->so_rcv.sb_flags |= SB_UPCALL;
340 return;
341
342fallout:
343 DPRINT("fallout");
344 so->so_upcall = NULL;
345 so->so_rcv.sb_flags &= ~SB_UPCALL;
346 soisconnected(so);
347 return;
348}
349
350
351#define NCHRS 3
352
353static void
354soishttpconnected(struct socket *so, void *arg, int events, int waitflag)
355{
356 char a, b, c;
357 struct mbuf *m, *n;
358 int ccleft, copied;
359
360 DPRINT("start");
361 if ((so->so_state & SS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv))
362 goto gotit;
363
364 /*
365 * Walk the socketbuffer and copy the last NCHRS (3) into a, b, and c
366 * copied - how much we've copied so far
367 * ccleft - how many bytes remaining in the socketbuffer
368 * just loop over the mbufs subtracting from 'ccleft' until we only
369 * have NCHRS left
370 */
371 copied = 0;
372 ccleft = so->so_rcv.sb_cc;
373 if (ccleft < NCHRS)
374 goto readmore;
375 a = b = c = '\0';
376 for (m = so->so_rcv.sb_mb; m; m = n) {
377 n = m->m_nextpkt;
378 for (; m; m = m->m_next) {
379 ccleft -= m->m_len;
380 if (ccleft <= NCHRS) {
381 char *src;
382 int tocopy;
383
384 tocopy = (NCHRS - ccleft) - copied;
385 src = mtod(m, char *) + (m->m_len - tocopy);
386
387 while (tocopy--) {
388 switch (copied++) {
389 case 0:
390 a = *src++;
391 break;
392 case 1:
393 b = *src++;
394 break;
395 case 2:
396 c = *src++;
397 break;
398 }
399 }
400 }
401 }
402 }
403 if (c == '\n' && (b == '\n' || (b == '\r' && a == '\n'))) {
404 /* we have all request headers */
405 goto gotit;
406 }
407
408readmore:
409 so->so_upcall = soishttpconnected;
410 so->so_rcv.sb_flags |= SB_UPCALL;
411 return;
412
413gotit:
414 so->so_upcall = NULL;
415 so->so_rcv.sb_flags &= ~SB_UPCALL;
416 soisconnected(so);
417 return;
418}
419