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[/] [or1k_soc_on_altera_embedded_dev_kit/] [trunk/] [linux-2.6/] [linux-2.6.24/] [net/] [sched/] [act_nat.c] - Blame information for rev 3

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Line No. Rev Author Line
1 3 xianfeng 
/*
2 
 * Stateless NAT actions
3 
 *
4 
 * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
5 
 *
6 
 * This program is free software; you can redistribute it and/or modify it
7 
 * under the terms of the GNU General Public License as published by the Free
8 
 * Software Foundation; either version 2 of the License, or (at your option)
9 
 * any later version.
10 
 */
11 
 
12 
#include <linux/errno.h>
13 
#include <linux/init.h>
14 
#include <linux/kernel.h>
15 
#include <linux/module.h>
16 
#include <linux/netfilter.h>
17 
#include <linux/rtnetlink.h>
18 
#include <linux/skbuff.h>
19 
#include <linux/slab.h>
20 
#include <linux/spinlock.h>
21 
#include <linux/string.h>
22 
#include <linux/tc_act/tc_nat.h>
23 
#include <net/act_api.h>
24 
#include <net/icmp.h>
25 
#include <net/ip.h>
26 
#include <net/netlink.h>
27 
#include <net/tc_act/tc_nat.h>
28 
#include <net/tcp.h>
29 
#include <net/udp.h>
30 
 
31 
 
32 
#define NAT_TAB_MASK    15
33 
static struct tcf_common *tcf_nat_ht[NAT_TAB_MASK + 1];
34 
static u32 nat_idx_gen;
35 
static DEFINE_RWLOCK(nat_lock);
36 
 
37 
static struct tcf_hashinfo nat_hash_info = {
38 
        .htab   =       tcf_nat_ht,
39 
        .hmask  =       NAT_TAB_MASK,
40 
        .lock   =       &nat_lock,
41 
};
42 
 
43 
static int tcf_nat_init(struct rtattr *rta, struct rtattr *est,
44 
                        struct tc_action *a, int ovr, int bind)
45 
{
46 
        struct rtattr *tb[TCA_NAT_MAX];
47 
        struct tc_nat *parm;
48 
        int ret = 0;
49 
        struct tcf_nat *p;
50 
        struct tcf_common *pc;
51 
 
52 
        if (rta == NULL || rtattr_parse_nested(tb, TCA_NAT_MAX, rta) < 0)
53 
                return -EINVAL;
54 
 
55 
        if (tb[TCA_NAT_PARMS - 1] == NULL ||
56 
            RTA_PAYLOAD(tb[TCA_NAT_PARMS - 1]) < sizeof(*parm))
57 
                return -EINVAL;
58 
        parm = RTA_DATA(tb[TCA_NAT_PARMS - 1]);
59 
 
60 
        pc = tcf_hash_check(parm->index, a, bind, &nat_hash_info);
61 
        if (!pc) {
62 
                pc = tcf_hash_create(parm->index, est, a, sizeof(*p), bind,
63 
                                     &nat_idx_gen, &nat_hash_info);
64 
                if (unlikely(!pc))
65 
                        return -ENOMEM;
66 
                p = to_tcf_nat(pc);
67 
                ret = ACT_P_CREATED;
68 
        } else {
69 
                p = to_tcf_nat(pc);
70 
                if (!ovr) {
71 
                        tcf_hash_release(pc, bind, &nat_hash_info);
72 
                        return -EEXIST;
73 
                }
74 
        }
75 
 
76 
        spin_lock_bh(&p->tcf_lock);
77 
        p->old_addr = parm->old_addr;
78 
        p->new_addr = parm->new_addr;
79 
        p->mask = parm->mask;
80 
        p->flags = parm->flags;
81 
 
82 
        p->tcf_action = parm->action;
83 
        spin_unlock_bh(&p->tcf_lock);
84 
 
85 
        if (ret == ACT_P_CREATED)
86 
                tcf_hash_insert(pc, &nat_hash_info);
87 
 
88 
        return ret;
89 
}
90 
 
91 
static int tcf_nat_cleanup(struct tc_action *a, int bind)
92 
{
93 
        struct tcf_nat *p = a->priv;
94 
 
95 
        return tcf_hash_release(&p->common, bind, &nat_hash_info);
96 
}
97 
 
98 
static int tcf_nat(struct sk_buff *skb, struct tc_action *a,
99 
                   struct tcf_result *res)
100 
{
101 
        struct tcf_nat *p = a->priv;
102 
        struct iphdr *iph;
103 
        __be32 old_addr;
104 
        __be32 new_addr;
105 
        __be32 mask;
106 
        __be32 addr;
107 
        int egress;
108 
        int action;
109 
        int ihl;
110 
 
111 
        spin_lock(&p->tcf_lock);
112 
 
113 
        p->tcf_tm.lastuse = jiffies;
114 
        old_addr = p->old_addr;
115 
        new_addr = p->new_addr;
116 
        mask = p->mask;
117 
        egress = p->flags & TCA_NAT_FLAG_EGRESS;
118 
        action = p->tcf_action;
119 
 
120 
        p->tcf_bstats.bytes += skb->len;
121 
        p->tcf_bstats.packets++;
122 
 
123 
        spin_unlock(&p->tcf_lock);
124 
 
125 
        if (unlikely(action == TC_ACT_SHOT))
126 
                goto drop;
127 
 
128 
        if (!pskb_may_pull(skb, sizeof(*iph)))
129 
                goto drop;
130 
 
131 
        iph = ip_hdr(skb);
132 
 
133 
        if (egress)
134 
                addr = iph->saddr;
135 
        else
136 
                addr = iph->daddr;
137 
 
138 
        if (!((old_addr ^ addr) & mask)) {
139 
                if (skb_cloned(skb) &&
140 
                    !skb_clone_writable(skb, sizeof(*iph)) &&
141 
                    pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
142 
                        goto drop;
143 
 
144 
                new_addr &= mask;
145 
                new_addr |= addr & ~mask;
146 
 
147 
                /* Rewrite IP header */
148 
                iph = ip_hdr(skb);
149 
                if (egress)
150 
                        iph->saddr = new_addr;
151 
                else
152 
                        iph->daddr = new_addr;
153 
 
154 
                nf_csum_replace4(&iph->check, addr, new_addr);
155 
        }
156 
 
157 
        ihl = iph->ihl * 4;
158 
 
159 
        /* It would be nice to share code with stateful NAT. */
160 
        switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
161 
        case IPPROTO_TCP:
162 
        {
163 
                struct tcphdr *tcph;
164 
 
165 
                if (!pskb_may_pull(skb, ihl + sizeof(*tcph)) ||
166 
                    (skb_cloned(skb) &&
167 
                     !skb_clone_writable(skb, ihl + sizeof(*tcph)) &&
168 
                     pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
169 
                        goto drop;
170 
 
171 
                tcph = (void *)(skb_network_header(skb) + ihl);
172 
                nf_proto_csum_replace4(&tcph->check, skb, addr, new_addr, 1);
173 
                break;
174 
        }
175 
        case IPPROTO_UDP:
176 
        {
177 
                struct udphdr *udph;
178 
 
179 
                if (!pskb_may_pull(skb, ihl + sizeof(*udph)) ||
180 
                    (skb_cloned(skb) &&
181 
                     !skb_clone_writable(skb, ihl + sizeof(*udph)) &&
182 
                     pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
183 
                        goto drop;
184 
 
185 
                udph = (void *)(skb_network_header(skb) + ihl);
186 
                if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) {
187 
                        nf_proto_csum_replace4(&udph->check, skb, addr,
188 
                                               new_addr, 1);
189 
                        if (!udph->check)
190 
                                udph->check = CSUM_MANGLED_0;
191 
                }
192 
                break;
193 
        }
194 
        case IPPROTO_ICMP:
195 
        {
196 
                struct icmphdr *icmph;
197 
 
198 
                if (!pskb_may_pull(skb, ihl + sizeof(*icmph) + sizeof(*iph)))
199 
                        goto drop;
200 
 
201 
                icmph = (void *)(skb_network_header(skb) + ihl);
202 
 
203 
                if ((icmph->type != ICMP_DEST_UNREACH) &&
204 
                    (icmph->type != ICMP_TIME_EXCEEDED) &&
205 
                    (icmph->type != ICMP_PARAMETERPROB))
206 
                        break;
207 
 
208 
                iph = (void *)(icmph + 1);
209 
                if (egress)
210 
                        addr = iph->daddr;
211 
                else
212 
                        addr = iph->saddr;
213 
 
214 
                if ((old_addr ^ addr) & mask)
215 
                        break;
216 
 
217 
                if (skb_cloned(skb) &&
218 
                    !skb_clone_writable(skb,
219 
                                        ihl + sizeof(*icmph) + sizeof(*iph)) &&
220 
                    pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
221 
                        goto drop;
222 
 
223 
                icmph = (void *)(skb_network_header(skb) + ihl);
224 
                iph = (void *)(icmph + 1);
225 
 
226 
                new_addr &= mask;
227 
                new_addr |= addr & ~mask;
228 
 
229 
                /* XXX Fix up the inner checksums. */
230 
                if (egress)
231 
                        iph->daddr = new_addr;
232 
                else
233 
                        iph->saddr = new_addr;
234 
 
235 
                nf_proto_csum_replace4(&icmph->checksum, skb, addr, new_addr,
236 
                                       1);
237 
                break;
238 
        }
239 
        default:
240 
                break;
241 
        }
242 
 
243 
        return action;
244 
 
245 
drop:
246 
        spin_lock(&p->tcf_lock);
247 
        p->tcf_qstats.drops++;
248 
        spin_unlock(&p->tcf_lock);
249 
        return TC_ACT_SHOT;
250 
}
251 
 
252 
static int tcf_nat_dump(struct sk_buff *skb, struct tc_action *a,
253 
                        int bind, int ref)
254 
{
255 
        unsigned char *b = skb_tail_pointer(skb);
256 
        struct tcf_nat *p = a->priv;
257 
        struct tc_nat *opt;
258 
        struct tcf_t t;
259 
        int s;
260 
 
261 
        s = sizeof(*opt);
262 
 
263 
        /* netlink spinlocks held above us - must use ATOMIC */
264 
        opt = kzalloc(s, GFP_ATOMIC);
265 
        if (unlikely(!opt))
266 
                return -ENOBUFS;
267 
 
268 
        opt->old_addr = p->old_addr;
269 
        opt->new_addr = p->new_addr;
270 
        opt->mask = p->mask;
271 
        opt->flags = p->flags;
272 
 
273 
        opt->index = p->tcf_index;
274 
        opt->action = p->tcf_action;
275 
        opt->refcnt = p->tcf_refcnt - ref;
276 
        opt->bindcnt = p->tcf_bindcnt - bind;
277 
 
278 
        RTA_PUT(skb, TCA_NAT_PARMS, s, opt);
279 
        t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
280 
        t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
281 
        t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
282 
        RTA_PUT(skb, TCA_NAT_TM, sizeof(t), &t);
283 
 
284 
        kfree(opt);
285 
 
286 
        return skb->len;
287 
 
288 
rtattr_failure:
289 
        nlmsg_trim(skb, b);
290 
        kfree(opt);
291 
        return -1;
292 
}
293 
 
294 
static struct tc_action_ops act_nat_ops = {
295 
        .kind           =       "nat",
296 
        .hinfo          =       &nat_hash_info,
297 
        .type           =       TCA_ACT_NAT,
298 
        .capab          =       TCA_CAP_NONE,
299 
        .owner          =       THIS_MODULE,
300 
        .act            =       tcf_nat,
301 
        .dump           =       tcf_nat_dump,
302 
        .cleanup        =       tcf_nat_cleanup,
303 
        .lookup         =       tcf_hash_search,
304 
        .init           =       tcf_nat_init,
305 
        .walk           =       tcf_generic_walker
306 
};
307 
 
308 
MODULE_DESCRIPTION("Stateless NAT actions");
309 
MODULE_LICENSE("GPL");
310 
 
311 
static int __init nat_init_module(void)
312 
{
313 
        return tcf_register_action(&act_nat_ops);
314 
}
315 
 
316 
static void __exit nat_cleanup_module(void)
317 
{
318 
        tcf_unregister_action(&act_nat_ops);
319 
}
320 
 
321 
module_init(nat_init_module);
322 
module_exit(nat_cleanup_module);

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