aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/ipfilter/ip_frag.c
blob: 6665404b983020b32ea6ff2e0e97949672f3ba50 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
/*
 * (C)opyright 1993,1994,1995 by Darren Reed.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that this notice is preserved and due credit is given
 * to the original author and the contributors.
 */
#if !defined(lint) && defined(LIBC_SCCS)
static	char	sccsid[] = "@(#)ip_frag.c	1.11 3/24/96 (C) 1993-1995 Darren Reed";
static	char	rcsid[] = "$Id: ip_frag.c,v 2.0.1.1 1997/01/09 15:14:43 darrenr Exp $";
#endif

#if !defined(_KERNEL) && !defined(KERNEL)
# include <string.h>
# include <stdlib.h>
#endif
#include <sys/errno.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/uio.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#ifdef	_KERNEL
# include <sys/systm.h>
#endif
#if !defined(__SVR4) && !defined(__svr4__)
# include <sys/mbuf.h>
#else
# include <sys/byteorder.h>
# include <sys/dditypes.h>
# include <sys/stream.h>
# include <sys/kmem.h>
#endif

#include <net/if.h>
#ifdef sun
#include <net/af.h>
#endif
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/tcp.h>
#include <netinet/udp.h>
#include <netinet/tcpip.h>
#include <netinet/ip_icmp.h>
#include "ip_fil.h"
#include "ip_compat.h"
#include "ip_frag.h"
#include "ip_nat.h"
#include "ip_state.h"

ipfr_t	*ipfr_heads[IPFT_SIZE];
ipfrstat_t ipfr_stats;
u_long	ipfr_inuse = 0,
	fr_ipfrttl = 120;	/* 60 seconds */
#ifdef _KERNEL
extern	int	ipfr_timer_id;
#endif
#if	SOLARIS
# ifdef	_KERNEL
extern	kmutex_t	ipf_frag;
# else
#define	bcmp(a,b,c)	memcmp(a,b,c)
#define	bcopy(a,b,c)	memmove(b,a,c)
# endif
#endif


ipfrstat_t *ipfr_fragstats()
{
	ipfr_stats.ifs_table = ipfr_heads;
	ipfr_stats.ifs_inuse = ipfr_inuse;
	return &ipfr_stats;
}


/*
 * add a new entry to the fragment cache, registering it as having come
 * through this box, with the result of the filter operation.
 */
int ipfr_newfrag(ip, fin, pass)
ip_t *ip;
fr_info_t *fin;
int pass;
{
	ipfr_t	**fp, *fr, frag;
	u_int	idx;

	frag.ipfr_p = ip->ip_p;
	idx = ip->ip_p;
	frag.ipfr_id = ip->ip_id;
	idx += ip->ip_id;
	frag.ipfr_tos = ip->ip_tos;
	frag.ipfr_src.s_addr = ip->ip_src.s_addr;
	idx += ip->ip_src.s_addr;
	frag.ipfr_dst.s_addr = ip->ip_dst.s_addr;
	idx += ip->ip_dst.s_addr;
	idx *= 127;
	idx %= IPFT_SIZE;

	/*
	 * first, make sure it isn't already there...
	 */
	MUTEX_ENTER(&ipf_frag);
	for (fp = &ipfr_heads[idx]; (fr = *fp); fp = &fr->ipfr_next)
		if (!bcmp((char *)&frag.ipfr_src, (char *)&fr->ipfr_src,
			  IPFR_CMPSZ)) {
			ipfr_stats.ifs_exists++;
			MUTEX_EXIT(&ipf_frag);
			return -1;
		}

	if (!(fr = (ipfr_t *)KMALLOC(sizeof(*fr)))) {
		ipfr_stats.ifs_nomem++;
		MUTEX_EXIT(&ipf_frag);
		return -1;
	}
	if ((fr->ipfr_next = ipfr_heads[idx]))
		ipfr_heads[idx]->ipfr_prev = fr;
	fr->ipfr_prev = NULL;
	ipfr_heads[idx] = fr;
	bcopy((char *)&frag.ipfr_src, (char *)&fr->ipfr_src, IPFR_CMPSZ);
	fr->ipfr_ttl = fr_ipfrttl;
	fr->ipfr_pass = pass & ~(FR_LOGFIRST|FR_LOG);
	fr->ipfr_off = (ip->ip_off & 0x1fff) + (fin->fin_dlen >> 3);
	*fp = fr;
	ipfr_stats.ifs_new++;
	ipfr_inuse++;
	MUTEX_EXIT(&ipf_frag);
	return 0;
}


/*
 * check the fragment cache to see if there is already a record of this packet
 * with its filter result known.
 */
int ipfr_knownfrag(ip, fin)
ip_t *ip;
fr_info_t *fin;
{
	ipfr_t	*f, frag;
	u_int	idx;
	int	ret;

	/*
	 * For fragments, we record protocol, packet id, TOS and both IP#'s
	 * (these should all be the same for all fragments of a packet).
	 */
	frag.ipfr_p = ip->ip_p;
	idx = ip->ip_p;
	frag.ipfr_id = ip->ip_id;
	idx += ip->ip_id;
	frag.ipfr_tos = ip->ip_tos;
	frag.ipfr_src.s_addr = ip->ip_src.s_addr;
	idx += ip->ip_src.s_addr;
	frag.ipfr_dst.s_addr = ip->ip_dst.s_addr;
	idx += ip->ip_dst.s_addr;
	idx *= 127;
	idx %= IPFT_SIZE;

	MUTEX_ENTER(&ipf_frag);
	for (f = ipfr_heads[idx]; f; f = f->ipfr_next)
		if (!bcmp((char *)&frag.ipfr_src, (char *)&f->ipfr_src,
			  IPFR_CMPSZ)) {
			u_short	atoff, off;

			if (f != ipfr_heads[idx]) {
				/*
				 * move fragment info. to the top of the list
				 * to speed up searches.
				 */
				if ((f->ipfr_prev->ipfr_next = f->ipfr_next))
					f->ipfr_next->ipfr_prev = f->ipfr_prev;
				f->ipfr_next = ipfr_heads[idx];
				ipfr_heads[idx]->ipfr_prev = f;
				f->ipfr_prev = NULL;
				ipfr_heads[idx] = f;
			}
			ret = f->ipfr_pass;
			off = ip->ip_off;
			atoff = (off & 0x1fff) - (fin->fin_dlen >> 3);
			/*
			 * If we've follwed the fragments, and this is the
			 * last (in order), shrink expiration time.
			 */
			if (atoff == f->ipfr_off) {
				if (!(off & IP_MF))
					f->ipfr_ttl = 1;
				else
					f->ipfr_off = off;
			}
			ipfr_stats.ifs_hits++;
			MUTEX_EXIT(&ipf_frag);
			return ret;
		}
	MUTEX_EXIT(&ipf_frag);
	return 0;
}


/*
 * Free memory in use by fragment state info. kept.
 */
void ipfr_unload()
{
	ipfr_t	**fp, *fr;
	int	idx;
#if	!SOLARIS && defined(_KERNEL)
	int	s;
#endif

	MUTEX_ENTER(&ipf_frag);
	SPLNET(s);
	for (idx = IPFT_SIZE - 1; idx >= 0; idx--)
		for (fp = &ipfr_heads[idx]; (fr = *fp); ) {
			*fp = fr->ipfr_next;
			KFREE(fr);
		}
	SPLX(s);
	MUTEX_EXIT(&ipf_frag);
}


#ifdef	_KERNEL
/*
 * Slowly expire held state for fragments.  Timeouts are set * in expectation
 * of this being called twice per second.
 */
# if BSD < 199306
int ipfr_slowtimer()
# else
void ipfr_slowtimer()
# endif
{
	ipfr_t	**fp, *fr;
	int	s, idx;

	MUTEX_ENTER(&ipf_frag);
	SPLNET(s);

	for (idx = IPFT_SIZE - 1; idx >= 0; idx--)
		for (fp = &ipfr_heads[idx]; (fr = *fp); ) {
			--fr->ipfr_ttl;
			if (fr->ipfr_ttl == 0) {
				if (fr->ipfr_prev)
					fr->ipfr_prev->ipfr_next =
					     fr->ipfr_next;
				if (fr->ipfr_next)
					fr->ipfr_next->ipfr_prev =
					     fr->ipfr_prev;
				*fp = fr->ipfr_next;
				ipfr_stats.ifs_expire++;
				ipfr_inuse--;
				KFREE(fr);
			} else
				fp = &fr->ipfr_next;
		}
	SPLX(s);
# if	SOLARIS
	MUTEX_EXIT(&ipf_frag);
	fr_timeoutstate();
	ip_natexpire();
	ipfr_timer_id = timeout(ipfr_slowtimer, NULL, HZ/2);
# else
	fr_timeoutstate();
	ip_natexpire();
	ip_slowtimo();
#  if BSD < 199306
	return 0;
#  endif
# endif
}
#endif /* defined(_KERNEL) */