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 <linux/types.h>
13#include <linux/kernel.h>
14#include <linux/string.h>
15#include <linux/errno.h>
16#include <linux/skbuff.h>
17#include <linux/rtnetlink.h>
18#include <linux/module.h>
19#include <linux/init.h>
20#include <linux/slab.h>
21#include <net/netlink.h>
22#include <net/pkt_sched.h>
23#include <linux/tc_act/tc_pedit.h>
24#include <net/tc_act/tc_pedit.h>
25
26#define PEDIT_TAB_MASK	15
27static struct tcf_common *tcf_pedit_ht[PEDIT_TAB_MASK + 1];
28static u32 pedit_idx_gen;
29static DEFINE_RWLOCK(pedit_lock);
30
31static struct tcf_hashinfo pedit_hash_info = {
32	.htab	=	tcf_pedit_ht,
33	.hmask	=	PEDIT_TAB_MASK,
34	.lock	=	&pedit_lock,
35};
36
37static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
38	[TCA_PEDIT_PARMS]	= { .len = sizeof(struct tc_pedit) },
39};
40
41static int tcf_pedit_init(struct net *net, struct nlattr *nla,
42			  struct nlattr *est, struct tc_action *a,
43			  int ovr, int bind)
44{
45	struct nlattr *tb[TCA_PEDIT_MAX + 1];
46	struct tc_pedit *parm;
47	int ret = 0, err;
48	struct tcf_pedit *p;
49	struct tcf_common *pc;
50	struct tc_pedit_key *keys = NULL;
51	int ksize;
52
53	if (nla == NULL)
54		return -EINVAL;
55
56	err = nla_parse_nested(tb, TCA_PEDIT_MAX, nla, pedit_policy);
57	if (err < 0)
58		return err;
59
60	if (tb[TCA_PEDIT_PARMS] == NULL)
61		return -EINVAL;
62	parm = nla_data(tb[TCA_PEDIT_PARMS]);
63	ksize = parm->nkeys * sizeof(struct tc_pedit_key);
64	if (nla_len(tb[TCA_PEDIT_PARMS]) < sizeof(*parm) + ksize)
65		return -EINVAL;
66
67	pc = tcf_hash_check(parm->index, a, bind, &pedit_hash_info);
68	if (!pc) {
69		if (!parm->nkeys)
70			return -EINVAL;
71		pc = tcf_hash_create(parm->index, est, a, sizeof(*p), bind,
72				     &pedit_idx_gen, &pedit_hash_info);
73		if (IS_ERR(pc))
74			return PTR_ERR(pc);
75		p = to_pedit(pc);
76		keys = kmalloc(ksize, GFP_KERNEL);
77		if (keys == NULL) {
78			if (est)
79				gen_kill_estimator(&pc->tcfc_bstats,
80						   &pc->tcfc_rate_est);
81			kfree_rcu(pc, tcfc_rcu);
82			return -ENOMEM;
83		}
84		ret = ACT_P_CREATED;
85	} else {
86		p = to_pedit(pc);
87		if (!ovr) {
88			tcf_hash_release(pc, bind, &pedit_hash_info);
89			return -EEXIST;
90		}
91		if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) {
92			keys = kmalloc(ksize, GFP_KERNEL);
93			if (keys == NULL)
94				return -ENOMEM;
95		}
96	}
97
98	spin_lock_bh(&p->tcf_lock);
99	p->tcfp_flags = parm->flags;
100	p->tcf_action = parm->action;
101	if (keys) {
102		kfree(p->tcfp_keys);
103		p->tcfp_keys = keys;
104		p->tcfp_nkeys = parm->nkeys;
105	}
106	memcpy(p->tcfp_keys, parm->keys, ksize);
107	spin_unlock_bh(&p->tcf_lock);
108	if (ret == ACT_P_CREATED)
109		tcf_hash_insert(pc, &pedit_hash_info);
110	return ret;
111}
112
113static int tcf_pedit_cleanup(struct tc_action *a, int bind)
114{
115	struct tcf_pedit *p = a->priv;
116
117	if (p) {
118		struct tc_pedit_key *keys = p->tcfp_keys;
119		if (tcf_hash_release(&p->common, bind, &pedit_hash_info)) {
120			kfree(keys);
121			return 1;
122		}
123	}
124	return 0;
125}
126
127static int tcf_pedit(struct sk_buff *skb, const struct tc_action *a,
128		     struct tcf_result *res)
129{
130	struct tcf_pedit *p = a->priv;
131	int i, munged = 0;
132	unsigned int off;
133
134	if (skb_unclone(skb, GFP_ATOMIC))
135		return p->tcf_action;
136
137	off = skb_network_offset(skb);
138
139	spin_lock(&p->tcf_lock);
140
141	p->tcf_tm.lastuse = jiffies;
142
143	if (p->tcfp_nkeys > 0) {
144		struct tc_pedit_key *tkey = p->tcfp_keys;
145
146		for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
147			u32 *ptr, _data;
148			int offset = tkey->off;
149
150			if (tkey->offmask) {
151				char *d, _d;
152
153				d = skb_header_pointer(skb, off + tkey->at, 1,
154						       &_d);
155				if (!d)
156					goto bad;
157				offset += (*d & tkey->offmask) >> tkey->shift;
158			}
159
160			if (offset % 4) {
161				pr_info("tc filter pedit"
162					" offset must be on 32 bit boundaries\n");
163				goto bad;
164			}
165			if (offset > 0 && offset > skb->len) {
166				pr_info("tc filter pedit"
167					" offset %d can't exceed pkt length %d\n",
168				       offset, skb->len);
169				goto bad;
170			}
171
172			ptr = skb_header_pointer(skb, off + offset, 4, &_data);
173			if (!ptr)
174				goto bad;
175			/* just do it, baby */
176			*ptr = ((*ptr & tkey->mask) ^ tkey->val);
177			if (ptr == &_data)
178				skb_store_bits(skb, off + offset, ptr, 4);
179			munged++;
180		}
181
182		if (munged)
183			skb->tc_verd = SET_TC_MUNGED(skb->tc_verd);
184		goto done;
185	} else
186		WARN(1, "pedit BUG: index %d\n", p->tcf_index);
187
188bad:
189	p->tcf_qstats.overlimits++;
190done:
191	bstats_update(&p->tcf_bstats, skb);
192	spin_unlock(&p->tcf_lock);
193	return p->tcf_action;
194}
195
196static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
197			  int bind, int ref)
198{
199	unsigned char *b = skb_tail_pointer(skb);
200	struct tcf_pedit *p = a->priv;
201	struct tc_pedit *opt;
202	struct tcf_t t;
203	int s;
204
205	s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key);
206
207	/* netlink spinlocks held above us - must use ATOMIC */
208	opt = kzalloc(s, GFP_ATOMIC);
209	if (unlikely(!opt))
210		return -ENOBUFS;
211
212	memcpy(opt->keys, p->tcfp_keys,
213	       p->tcfp_nkeys * sizeof(struct tc_pedit_key));
214	opt->index = p->tcf_index;
215	opt->nkeys = p->tcfp_nkeys;
216	opt->flags = p->tcfp_flags;
217	opt->action = p->tcf_action;
218	opt->refcnt = p->tcf_refcnt - ref;
219	opt->bindcnt = p->tcf_bindcnt - bind;
220
221	if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
222		goto nla_put_failure;
223	t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
224	t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
225	t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
226	if (nla_put(skb, TCA_PEDIT_TM, sizeof(t), &t))
227		goto nla_put_failure;
228	kfree(opt);
229	return skb->len;
230
231nla_put_failure:
232	nlmsg_trim(skb, b);
233	kfree(opt);
234	return -1;
235}
236
237static struct tc_action_ops act_pedit_ops = {
238	.kind		=	"pedit",
239	.hinfo		=	&pedit_hash_info,
240	.type		=	TCA_ACT_PEDIT,
241	.capab		=	TCA_CAP_NONE,
242	.owner		=	THIS_MODULE,
243	.act		=	tcf_pedit,
244	.dump		=	tcf_pedit_dump,
245	.cleanup	=	tcf_pedit_cleanup,
246	.lookup		=	tcf_hash_search,
247	.init		=	tcf_pedit_init,
248	.walk		=	tcf_generic_walker
249};
250
251MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
252MODULE_DESCRIPTION("Generic Packet Editor actions");
253MODULE_LICENSE("GPL");
254
255static int __init pedit_init_module(void)
256{
257	return tcf_register_action(&act_pedit_ops);
258}
259
260static void __exit pedit_cleanup_module(void)
261{
262	tcf_unregister_action(&act_pedit_ops);
263}
264
265module_init(pedit_init_module);
266module_exit(pedit_cleanup_module);
267
268