Make all network interrupt service routines MPSAFE part 1/3.
[dragonfly.git] / sys / netinet / ip_flow.c
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1/*-
2 * Copyright (c) 1998 The NetBSD Foundation, Inc.
3 * All rights reserved.
4 *
5 * This code is derived from software contributed to The NetBSD Foundation
6 * by the 3am Software Foundry ("3am"). It was developed by Matt Thomas.
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 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the NetBSD
19 * Foundation, Inc. and its contributors.
20 * 4. Neither the name of The NetBSD Foundation nor the names of its
21 * contributors may be used to endorse or promote products derived
22 * from this software without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
25 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
26 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
27 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
28 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
32 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34 * POSSIBILITY OF SUCH DAMAGE.
35 *
36 * $FreeBSD: src/sys/netinet/ip_flow.c,v 1.9.2.2 2001/11/04 17:35:31 luigi Exp $
78195a76 37 * $DragonFly: src/sys/netinet/ip_flow.c,v 1.9 2005/11/28 17:13:46 dillon Exp $
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38 */
39
40#include <sys/param.h>
41#include <sys/systm.h>
42#include <sys/malloc.h>
43#include <sys/mbuf.h>
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44#include <sys/globaldata.h>
45#include <sys/thread.h>
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46#include <sys/protosw.h>
47#include <sys/socket.h>
48#include <sys/kernel.h>
49
50#include <sys/sysctl.h>
1cae611f 51#include <sys/thread2.h>
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52
53#include <net/if.h>
54#include <net/route.h>
55
56#include <netinet/in.h>
57#include <netinet/in_systm.h>
58#include <netinet/ip.h>
59#include <netinet/in_var.h>
60#include <netinet/ip_var.h>
61#include <netinet/ip_flow.h>
62
63#define IPFLOW_TIMER (5 * PR_SLOWHZ)
64#define IPFLOW_HASHBITS 6 /* should not be a multiple of 8 */
65#define IPFLOW_HASHSIZE (1 << IPFLOW_HASHBITS)
66static LIST_HEAD(ipflowhead, ipflow) ipflows[IPFLOW_HASHSIZE];
67static int ipflow_inuse;
68#define IPFLOW_MAX 256
69
70static int ipflow_active = 0;
71SYSCTL_INT(_net_inet_ip, IPCTL_FASTFORWARDING, fastforwarding, CTLFLAG_RW,
72 &ipflow_active, 0, "Enable flow-based IP forwarding");
73
74static MALLOC_DEFINE(M_IPFLOW, "ip_flow", "IP flow");
75
76static unsigned
be23faf1 77ipflow_hash(struct in_addr dst, struct in_addr src, unsigned tos)
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78{
79 unsigned hash = tos;
80 int idx;
be23faf1 81
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82 for (idx = 0; idx < 32; idx += IPFLOW_HASHBITS)
83 hash += (dst.s_addr >> (32 - idx)) + (src.s_addr >> idx);
84 return hash & (IPFLOW_HASHSIZE-1);
85}
86
87static struct ipflow *
be23faf1 88ipflow_lookup(const struct ip *ip)
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89{
90 unsigned hash;
91 struct ipflow *ipf;
92
93 hash = ipflow_hash(ip->ip_dst, ip->ip_src, ip->ip_tos);
94
95 ipf = LIST_FIRST(&ipflows[hash]);
96 while (ipf != NULL) {
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97 if (ip->ip_dst.s_addr == ipf->ipf_dst.s_addr &&
98 ip->ip_src.s_addr == ipf->ipf_src.s_addr &&
99 ip->ip_tos == ipf->ipf_tos)
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100 break;
101 ipf = LIST_NEXT(ipf, ipf_next);
102 }
103 return ipf;
104}
105
106int
78195a76 107ipflow_fastforward(struct mbuf *m, lwkt_serialize_t serializer)
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108{
109 struct ip *ip;
110 struct ipflow *ipf;
111 struct rtentry *rt;
112 struct sockaddr *dst;
113 int error;
114
115 /*
116 * Are we forwarding packets? Big enough for an IP packet?
117 */
118 if (!ipforwarding || !ipflow_active || m->m_len < sizeof(struct ip))
119 return 0;
120 /*
121 * IP header with no option and valid version and length
122 */
123 ip = mtod(m, struct ip *);
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124 if (ip->ip_v != IPVERSION || ip->ip_hl != (sizeof(struct ip) >> 2) ||
125 ntohs(ip->ip_len) > m->m_pkthdr.len)
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126 return 0;
127 /*
128 * Find a flow.
129 */
130 if ((ipf = ipflow_lookup(ip)) == NULL)
131 return 0;
132
133 /*
134 * Route and interface still up?
135 */
136 rt = ipf->ipf_ro.ro_rt;
137 if ((rt->rt_flags & RTF_UP) == 0 || (rt->rt_ifp->if_flags & IFF_UP) == 0)
138 return 0;
139
140 /*
141 * Packet size OK? TTL?
142 */
143 if (m->m_pkthdr.len > rt->rt_ifp->if_mtu || ip->ip_ttl <= IPTTLDEC)
144 return 0;
145
146 /*
147 * Everything checks out and so we can forward this packet.
148 * Modify the TTL and incrementally change the checksum.
149 */
150 ip->ip_ttl -= IPTTLDEC;
be23faf1 151 if (ip->ip_sum >= htons(0xffff - (IPTTLDEC << 8)))
984263bc 152 ip->ip_sum += htons(IPTTLDEC << 8) + 1;
be23faf1 153 else
984263bc 154 ip->ip_sum += htons(IPTTLDEC << 8);
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155
156 /*
157 * Send the packet on its way. All we can get back is ENOBUFS
158 */
159 ipf->ipf_uses++;
160 ipf->ipf_timer = IPFLOW_TIMER;
161
162 if (rt->rt_flags & RTF_GATEWAY)
163 dst = rt->rt_gateway;
164 else
165 dst = &ipf->ipf_ro.ro_dst;
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166 if (serializer)
167 lwkt_serialize_exit(serializer);
168 lwkt_serialize_enter(rt->rt_ifp->if_serializer);
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169 if ((error = (*rt->rt_ifp->if_output)(rt->rt_ifp, m, dst, rt)) != 0) {
170 if (error == ENOBUFS)
171 ipf->ipf_dropped++;
172 else
173 ipf->ipf_errors++;
174 }
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175 lwkt_serialize_exit(rt->rt_ifp->if_serializer);
176 if (serializer)
177 lwkt_serialize_enter(serializer);
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178 return 1;
179}
be23faf1 180
984263bc 181static void
be23faf1 182ipflow_addstats(struct ipflow *ipf)
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183{
184 ipf->ipf_ro.ro_rt->rt_use += ipf->ipf_uses;
185 ipstat.ips_cantforward += ipf->ipf_errors + ipf->ipf_dropped;
186 ipstat.ips_forward += ipf->ipf_uses;
187 ipstat.ips_fastforward += ipf->ipf_uses;
188}
189
190static void
be23faf1 191ipflow_free(struct ipflow *ipf)
984263bc 192{
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193 /*
194 * Remove the flow from the hash table (at elevated IPL).
195 * Once it's off the list, we can deal with it at normal
196 * network IPL.
197 */
1cae611f 198 crit_enter();
984263bc 199 LIST_REMOVE(ipf, ipf_next);
1cae611f 200 crit_exit();
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201 ipflow_addstats(ipf);
202 RTFREE(ipf->ipf_ro.ro_rt);
203 ipflow_inuse--;
204 free(ipf, M_IPFLOW);
205}
206
207static struct ipflow *
be23faf1 208ipflow_reap(void)
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209{
210 struct ipflow *ipf, *maybe_ipf = NULL;
211 int idx;
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212
213 for (idx = 0; idx < IPFLOW_HASHSIZE; idx++) {
214 ipf = LIST_FIRST(&ipflows[idx]);
215 while (ipf != NULL) {
216 /*
217 * If this no longer points to a valid route
218 * reclaim it.
219 */
220 if ((ipf->ipf_ro.ro_rt->rt_flags & RTF_UP) == 0)
221 goto done;
222 /*
223 * choose the one that's been least recently used
f23061d4 224 * or has had the least uses in the last 1.5
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225 * intervals.
226 */
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227 if (maybe_ipf == NULL ||
228 ipf->ipf_timer < maybe_ipf->ipf_timer ||
229 (ipf->ipf_timer == maybe_ipf->ipf_timer &&
230 ipf->ipf_last_uses + ipf->ipf_uses <
231 maybe_ipf->ipf_last_uses + maybe_ipf->ipf_uses))
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232 maybe_ipf = ipf;
233 ipf = LIST_NEXT(ipf, ipf_next);
234 }
235 }
236 ipf = maybe_ipf;
be23faf1 237done:
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238 /*
239 * Remove the entry from the flow table.
240 */
1cae611f 241 crit_enter();
984263bc 242 LIST_REMOVE(ipf, ipf_next);
1cae611f 243 crit_exit();
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244 ipflow_addstats(ipf);
245 RTFREE(ipf->ipf_ro.ro_rt);
246 return ipf;
247}
248
249void
be23faf1 250ipflow_slowtimo(void)
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251{
252 struct ipflow *ipf;
253 int idx;
254
255 for (idx = 0; idx < IPFLOW_HASHSIZE; idx++) {
256 ipf = LIST_FIRST(&ipflows[idx]);
257 while (ipf != NULL) {
258 struct ipflow *next_ipf = LIST_NEXT(ipf, ipf_next);
259 if (--ipf->ipf_timer == 0) {
260 ipflow_free(ipf);
261 } else {
262 ipf->ipf_last_uses = ipf->ipf_uses;
263 ipf->ipf_ro.ro_rt->rt_use += ipf->ipf_uses;
264 ipstat.ips_forward += ipf->ipf_uses;
265 ipstat.ips_fastforward += ipf->ipf_uses;
266 ipf->ipf_uses = 0;
267 }
268 ipf = next_ipf;
269 }
270 }
271}
272
273void
ba4e3dbe 274ipflow_create(const struct route *ro, struct mbuf *m)
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275{
276 const struct ip *const ip = mtod(m, struct ip *);
277 struct ipflow *ipf;
278 unsigned hash;
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279
280 /*
281 * Don't create cache entries for ICMP messages.
282 */
283 if (!ipflow_active || ip->ip_p == IPPROTO_ICMP)
284 return;
285 /*
286 * See if an existing flow struct exists. If so remove it from it's
287 * list and free the old route. If not, try to malloc a new one
288 * (if we aren't at our limit).
289 */
290 ipf = ipflow_lookup(ip);
291 if (ipf == NULL) {
292 if (ipflow_inuse == IPFLOW_MAX) {
293 ipf = ipflow_reap();
294 } else {
0c3c561c 295 ipf = malloc(sizeof *ipf, M_IPFLOW,
f23061d4 296 M_INTWAIT | M_NULLOK);
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297 if (ipf == NULL)
298 return;
299 ipflow_inuse++;
300 }
0c3c561c 301 bzero(ipf, sizeof *ipf);
984263bc 302 } else {
1cae611f 303 crit_enter();
984263bc 304 LIST_REMOVE(ipf, ipf_next);
1cae611f 305 crit_exit();
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306 ipflow_addstats(ipf);
307 RTFREE(ipf->ipf_ro.ro_rt);
308 ipf->ipf_uses = ipf->ipf_last_uses = 0;
309 ipf->ipf_errors = ipf->ipf_dropped = 0;
310 }
311
312 /*
313 * Fill in the updated information.
314 */
315 ipf->ipf_ro = *ro;
316 ro->ro_rt->rt_refcnt++;
317 ipf->ipf_dst = ip->ip_dst;
318 ipf->ipf_src = ip->ip_src;
319 ipf->ipf_tos = ip->ip_tos;
320 ipf->ipf_timer = IPFLOW_TIMER;
321 /*
322 * Insert into the approriate bucket of the flow table.
323 */
324 hash = ipflow_hash(ip->ip_dst, ip->ip_src, ip->ip_tos);
1cae611f 325 crit_enter();
984263bc 326 LIST_INSERT_HEAD(&ipflows[hash], ipf, ipf_next);
1cae611f 327 crit_exit();
984263bc 328}