accf_http.c revision 61837 
1/*-
2 * Copyright (c) 2000 Alfred Perlstein <alfred@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 *	$FreeBSD: head/sys/netinet/accf_http.c 61837 2000-06-20 01:09:23Z alfred $
27 */
28
29#define ACCEPT_FILTER_MOD
30
31#include <sys/param.h>
32#include <sys/systm.h>
33#include <sys/sysproto.h>
34#include <sys/kernel.h>
35#include <sys/proc.h>
36#include <sys/malloc.h>
37#include <sys/unistd.h>
38#include <sys/file.h>
39#include <sys/fcntl.h>
40#include <sys/protosw.h>
41#include <sys/socket.h>
42#include <sys/socketvar.h>
43#include <sys/stat.h>
44#include <sys/mbuf.h>
45#include <sys/resource.h>
46#include <sys/sysent.h>
47#include <sys/resourcevar.h>
48
49/*
50 * XXX: doesn't work with 0.9 requests, make a seperate filter
51 * based on this one if you want to decode those.
52 */
53
54/* check for GET */
55static void sohashttpget(struct socket *so, void *arg, int waitflag);
56/* check for end of HTTP request */
57static void soishttpconnected(struct socket *so, void *arg, int waitflag);
58static char sbindex(struct mbuf **mp, int *begin, int end);
59
60static struct accept_filter accf_http_filter = {
61	"httpready",
62	sohashttpget,
63	NULL,
64	NULL
65};
66
67static moduledata_t accf_http_mod = {
68	"accf_http",
69	accept_filt_generic_mod_event,
70	&accf_http_filter
71};
72
73DECLARE_MODULE(accf_http, accf_http_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE);
74
75
76static char
77sbindex(struct mbuf **mp, int *begin, int end)
78{
79	struct mbuf *m = *mp;
80	int diff = end - *begin + 1;
81
82	while (m->m_len < diff) {
83		*begin += m->m_len;
84		diff -= m->m_len;
85		if (m->m_next) {
86			m = m->m_next;
87		} else if (m->m_nextpkt) {
88			m = m->m_nextpkt;
89		} else {
90			/* only happens if end > data in socket buffer */
91			panic("sbindex: not enough data");
92		}
93	}
94	*mp = m;
95	return *(mtod(m, char *) + diff - 1);
96}
97
98static void
99sohashttpget(struct socket *so, void *arg, int waitflag)
100{
101
102	if ((so->so_state & SS_CANTRCVMORE) == 0) {
103		struct mbuf *m;
104
105		if (so->so_rcv.sb_cc < 6)
106			return;
107		m = so->so_rcv.sb_mb;
108		if (bcmp(mtod(m, char *), "GET ", 4) == 0) {
109			soishttpconnected(so, arg, waitflag);
110			return;
111		}
112	}
113
114	so->so_upcall = NULL;
115	so->so_rcv.sb_flags &= ~SB_UPCALL;
116	soisconnected(so);
117	return;
118}
119
120static void
121soishttpconnected(struct socket *so, void *arg, int waitflag)
122{
123	char a, b, c;
124	struct mbuf *y, *z;
125
126	if ((so->so_state & SS_CANTRCVMORE) == 0) {
127		/* seek to end and keep track of next to last mbuf */
128		y = so->so_rcv.sb_mb;
129		while (y->m_nextpkt)
130			y = y->m_nextpkt;
131		z = y;
132		while (y->m_next) {
133			z = y;
134			y = y->m_next;
135		}
136
137		if (z->m_len + y->m_len > 2) {
138			int index = y->m_len - 1;
139
140			c = *(mtod(y, char *) + index--);
141			switch (index) {
142			case -1:
143				y = z;
144				index = y->m_len - 1;
145				b = *(mtod(y, char *) + index--);
146				break;
147			case 0:
148				b = *(mtod(y, char *) + index--);
149				y = z;
150				index = y->m_len - 1;
151				break;
152			default:
153				b = *(mtod(y, char *) + index--);
154				break;
155			}
156			a = *(mtod(y, char *) + index--);
157		} else {
158			int begin = 0;
159			int end = so->so_rcv.sb_cc - 3;
160
161			y = so->so_rcv.sb_mb;
162			a = sbindex(&y, &begin, end++);
163			b = sbindex(&y, &begin, end++);
164			c = sbindex(&y, &begin, end++);
165		}
166
167		if (c == '\n' && (b == '\n' || (b == '\r' && a == '\n'))) {
168			/* we have all request headers */
169			goto done;
170		} else {
171			/* still need more data */
172			so->so_upcall = soishttpconnected;
173			so->so_rcv.sb_flags |= SB_UPCALL;
174			return;
175		}
176	}
177
178done:
179	so->so_upcall = NULL;
180	so->so_rcv.sb_flags &= ~SB_UPCALL;
181	soisconnected(so);
182	return;
183}
184