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