[SK_BUFF]: Introduce skb_network_header()
[linux-2.6.git] / net / sched / act_pedit.c
1 /*
2  * net/sched/pedit.c    Generic packet editor
3  *
4  *              This program is free software; you can redistribute it and/or
5  *              modify it under the terms of the GNU General Public License
6  *              as published by the Free Software Foundation; either version
7  *              2 of the License, or (at your option) any later version.
8  *
9  * Authors:     Jamal Hadi Salim (2002-4)
10  */
11
12 #include <asm/uaccess.h>
13 #include <asm/system.h>
14 #include <asm/bitops.h>
15 #include <linux/types.h>
16 #include <linux/kernel.h>
17 #include <linux/string.h>
18 #include <linux/mm.h>
19 #include <linux/socket.h>
20 #include <linux/sockios.h>
21 #include <linux/in.h>
22 #include <linux/errno.h>
23 #include <linux/interrupt.h>
24 #include <linux/netdevice.h>
25 #include <linux/skbuff.h>
26 #include <linux/rtnetlink.h>
27 #include <linux/module.h>
28 #include <linux/init.h>
29 #include <linux/proc_fs.h>
30 #include <net/sock.h>
31 #include <net/pkt_sched.h>
32 #include <linux/tc_act/tc_pedit.h>
33 #include <net/tc_act/tc_pedit.h>
34
35 #define PEDIT_TAB_MASK  15
36 static struct tcf_common *tcf_pedit_ht[PEDIT_TAB_MASK + 1];
37 static u32 pedit_idx_gen;
38 static DEFINE_RWLOCK(pedit_lock);
39
40 static struct tcf_hashinfo pedit_hash_info = {
41         .htab   =       tcf_pedit_ht,
42         .hmask  =       PEDIT_TAB_MASK,
43         .lock   =       &pedit_lock,
44 };
45
46 static int tcf_pedit_init(struct rtattr *rta, struct rtattr *est,
47                           struct tc_action *a, int ovr, int bind)
48 {
49         struct rtattr *tb[TCA_PEDIT_MAX];
50         struct tc_pedit *parm;
51         int ret = 0;
52         struct tcf_pedit *p;
53         struct tcf_common *pc;
54         struct tc_pedit_key *keys = NULL;
55         int ksize;
56
57         if (rta == NULL || rtattr_parse_nested(tb, TCA_PEDIT_MAX, rta) < 0)
58                 return -EINVAL;
59
60         if (tb[TCA_PEDIT_PARMS - 1] == NULL ||
61             RTA_PAYLOAD(tb[TCA_PEDIT_PARMS-1]) < sizeof(*parm))
62                 return -EINVAL;
63         parm = RTA_DATA(tb[TCA_PEDIT_PARMS-1]);
64         ksize = parm->nkeys * sizeof(struct tc_pedit_key);
65         if (RTA_PAYLOAD(tb[TCA_PEDIT_PARMS-1]) < sizeof(*parm) + ksize)
66                 return -EINVAL;
67
68         pc = tcf_hash_check(parm->index, a, bind, &pedit_hash_info);
69         if (!pc) {
70                 if (!parm->nkeys)
71                         return -EINVAL;
72                 pc = tcf_hash_create(parm->index, est, a, sizeof(*p), bind,
73                                      &pedit_idx_gen, &pedit_hash_info);
74                 if (unlikely(!pc))
75                         return -ENOMEM;
76                 p = to_pedit(pc);
77                 keys = kmalloc(ksize, GFP_KERNEL);
78                 if (keys == NULL) {
79                         kfree(pc);
80                         return -ENOMEM;
81                 }
82                 ret = ACT_P_CREATED;
83         } else {
84                 p = to_pedit(pc);
85                 if (!ovr) {
86                         tcf_hash_release(pc, bind, &pedit_hash_info);
87                         return -EEXIST;
88                 }
89                 if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) {
90                         keys = kmalloc(ksize, GFP_KERNEL);
91                         if (keys == NULL)
92                                 return -ENOMEM;
93                 }
94         }
95
96         spin_lock_bh(&p->tcf_lock);
97         p->tcfp_flags = parm->flags;
98         p->tcf_action = parm->action;
99         if (keys) {
100                 kfree(p->tcfp_keys);
101                 p->tcfp_keys = keys;
102                 p->tcfp_nkeys = parm->nkeys;
103         }
104         memcpy(p->tcfp_keys, parm->keys, ksize);
105         spin_unlock_bh(&p->tcf_lock);
106         if (ret == ACT_P_CREATED)
107                 tcf_hash_insert(pc, &pedit_hash_info);
108         return ret;
109 }
110
111 static int tcf_pedit_cleanup(struct tc_action *a, int bind)
112 {
113         struct tcf_pedit *p = a->priv;
114
115         if (p) {
116                 struct tc_pedit_key *keys = p->tcfp_keys;
117                 if (tcf_hash_release(&p->common, bind, &pedit_hash_info)) {
118                         kfree(keys);
119                         return 1;
120                 }
121         }
122         return 0;
123 }
124
125 static int tcf_pedit(struct sk_buff *skb, struct tc_action *a,
126                      struct tcf_result *res)
127 {
128         struct tcf_pedit *p = a->priv;
129         int i, munged = 0;
130         u8 *pptr;
131
132         if (!(skb->tc_verd & TC_OK2MUNGE)) {
133                 /* should we set skb->cloned? */
134                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
135                         return p->tcf_action;
136                 }
137         }
138
139         pptr = skb_network_header(skb);
140
141         spin_lock(&p->tcf_lock);
142
143         p->tcf_tm.lastuse = jiffies;
144
145         if (p->tcfp_nkeys > 0) {
146                 struct tc_pedit_key *tkey = p->tcfp_keys;
147
148                 for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
149                         u32 *ptr;
150                         int offset = tkey->off;
151
152                         if (tkey->offmask) {
153                                 if (skb->len > tkey->at) {
154                                          char *j = pptr + tkey->at;
155                                          offset += ((*j & tkey->offmask) >>
156                                                    tkey->shift);
157                                 } else {
158                                         goto bad;
159                                 }
160                         }
161
162                         if (offset % 4) {
163                                 printk("offset must be on 32 bit boundaries\n");
164                                 goto bad;
165                         }
166                         if (skb->len < 0 ||
167                             (offset > 0 && offset > skb->len)) {
168                                 printk("offset %d cant exceed pkt length %d\n",
169                                        offset, skb->len);
170                                 goto bad;
171                         }
172
173                         ptr = (u32 *)(pptr+offset);
174                         /* just do it, baby */
175                         *ptr = ((*ptr & tkey->mask) ^ tkey->val);
176                         munged++;
177                 }
178
179                 if (munged)
180                         skb->tc_verd = SET_TC_MUNGED(skb->tc_verd);
181                 goto done;
182         } else {
183                 printk("pedit BUG: index %d\n", p->tcf_index);
184         }
185
186 bad:
187         p->tcf_qstats.overlimits++;
188 done:
189         p->tcf_bstats.bytes += skb->len;
190         p->tcf_bstats.packets++;
191         spin_unlock(&p->tcf_lock);
192         return p->tcf_action;
193 }
194
195 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
196                           int bind, int ref)
197 {
198         unsigned char *b = skb->tail;
199         struct tcf_pedit *p = a->priv;
200         struct tc_pedit *opt;
201         struct tcf_t t;
202         int s;
203
204         s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key);
205
206         /* netlink spinlocks held above us - must use ATOMIC */
207         opt = kzalloc(s, GFP_ATOMIC);
208         if (unlikely(!opt))
209                 return -ENOBUFS;
210
211         memcpy(opt->keys, p->tcfp_keys,
212                p->tcfp_nkeys * sizeof(struct tc_pedit_key));
213         opt->index = p->tcf_index;
214         opt->nkeys = p->tcfp_nkeys;
215         opt->flags = p->tcfp_flags;
216         opt->action = p->tcf_action;
217         opt->refcnt = p->tcf_refcnt - ref;
218         opt->bindcnt = p->tcf_bindcnt - bind;
219
220         RTA_PUT(skb, TCA_PEDIT_PARMS, s, opt);
221         t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
222         t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
223         t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
224         RTA_PUT(skb, TCA_PEDIT_TM, sizeof(t), &t);
225         kfree(opt);
226         return skb->len;
227
228 rtattr_failure:
229         skb_trim(skb, b - skb->data);
230         kfree(opt);
231         return -1;
232 }
233
234 static struct tc_action_ops act_pedit_ops = {
235         .kind           =       "pedit",
236         .hinfo          =       &pedit_hash_info,
237         .type           =       TCA_ACT_PEDIT,
238         .capab          =       TCA_CAP_NONE,
239         .owner          =       THIS_MODULE,
240         .act            =       tcf_pedit,
241         .dump           =       tcf_pedit_dump,
242         .cleanup        =       tcf_pedit_cleanup,
243         .lookup         =       tcf_hash_search,
244         .init           =       tcf_pedit_init,
245         .walk           =       tcf_generic_walker
246 };
247
248 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
249 MODULE_DESCRIPTION("Generic Packet Editor actions");
250 MODULE_LICENSE("GPL");
251
252 static int __init pedit_init_module(void)
253 {
254         return tcf_register_action(&act_pedit_ops);
255 }
256
257 static void __exit pedit_cleanup_module(void)
258 {
259         tcf_unregister_action(&act_pedit_ops);
260 }
261
262 module_init(pedit_init_module);
263 module_exit(pedit_cleanup_module);
264