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CommitLineData
86da71b5
JHS
1/*
2 * net/sched/act_skbmod.c skb data modifier
3 *
4 * Copyright (c) 2016 Jamal Hadi Salim <jhs@mojatatu.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10*/
11
12#include <linux/module.h>
13#include <linux/init.h>
14#include <linux/kernel.h>
15#include <linux/skbuff.h>
16#include <linux/rtnetlink.h>
17#include <net/netlink.h>
18#include <net/pkt_sched.h>
19
20#include <linux/tc_act/tc_skbmod.h>
21#include <net/tc_act/tc_skbmod.h>
22
c7d03a00 23static unsigned int skbmod_net_id;
86da71b5
JHS
24static struct tc_action_ops act_skbmod_ops;
25
26#define MAX_EDIT_LEN ETH_HLEN
27static int tcf_skbmod_run(struct sk_buff *skb, const struct tc_action *a,
28 struct tcf_result *res)
29{
30 struct tcf_skbmod *d = to_skbmod(a);
31 int action;
32 struct tcf_skbmod_params *p;
33 u64 flags;
34 int err;
35
36 tcf_lastuse_update(&d->tcf_tm);
37 bstats_cpu_update(this_cpu_ptr(d->common.cpu_bstats), skb);
38
39 /* XXX: if you are going to edit more fields beyond ethernet header
40 * (example when you add IP header replacement or vlan swap)
41 * then MAX_EDIT_LEN needs to change appropriately
42 */
43 err = skb_ensure_writable(skb, MAX_EDIT_LEN);
44 if (unlikely(err)) { /* best policy is to drop on the floor */
45 qstats_overlimit_inc(this_cpu_ptr(d->common.cpu_qstats));
46 return TC_ACT_SHOT;
47 }
48
49 rcu_read_lock();
50 action = READ_ONCE(d->tcf_action);
51 if (unlikely(action == TC_ACT_SHOT)) {
52 qstats_overlimit_inc(this_cpu_ptr(d->common.cpu_qstats));
53 rcu_read_unlock();
54 return action;
55 }
56
57 p = rcu_dereference(d->skbmod_p);
58 flags = p->flags;
59 if (flags & SKBMOD_F_DMAC)
60 ether_addr_copy(eth_hdr(skb)->h_dest, p->eth_dst);
61 if (flags & SKBMOD_F_SMAC)
62 ether_addr_copy(eth_hdr(skb)->h_source, p->eth_src);
63 if (flags & SKBMOD_F_ETYPE)
64 eth_hdr(skb)->h_proto = p->eth_type;
65 rcu_read_unlock();
66
67 if (flags & SKBMOD_F_SWAPMAC) {
68 u16 tmpaddr[ETH_ALEN / 2]; /* ether_addr_copy() requirement */
69 /*XXX: I am sure we can come up with more efficient swapping*/
70 ether_addr_copy((u8 *)tmpaddr, eth_hdr(skb)->h_dest);
71 ether_addr_copy(eth_hdr(skb)->h_dest, eth_hdr(skb)->h_source);
72 ether_addr_copy(eth_hdr(skb)->h_source, (u8 *)tmpaddr);
73 }
74
75 return action;
76}
77
78static const struct nla_policy skbmod_policy[TCA_SKBMOD_MAX + 1] = {
79 [TCA_SKBMOD_PARMS] = { .len = sizeof(struct tc_skbmod) },
80 [TCA_SKBMOD_DMAC] = { .len = ETH_ALEN },
81 [TCA_SKBMOD_SMAC] = { .len = ETH_ALEN },
82 [TCA_SKBMOD_ETYPE] = { .type = NLA_U16 },
83};
84
85static int tcf_skbmod_init(struct net *net, struct nlattr *nla,
86 struct nlattr *est, struct tc_action **a,
789871bb
VB
87 int ovr, int bind, bool rtnl_held,
88 struct netlink_ext_ack *extack)
86da71b5
JHS
89{
90 struct tc_action_net *tn = net_generic(net, skbmod_net_id);
91 struct nlattr *tb[TCA_SKBMOD_MAX + 1];
92 struct tcf_skbmod_params *p, *p_old;
93 struct tc_skbmod *parm;
94 struct tcf_skbmod *d;
95 bool exists = false;
96 u8 *daddr = NULL;
97 u8 *saddr = NULL;
98 u16 eth_type = 0;
99 u32 lflags = 0;
100 int ret = 0, err;
101
102 if (!nla)
103 return -EINVAL;
104
fceb6435 105 err = nla_parse_nested(tb, TCA_SKBMOD_MAX, nla, skbmod_policy, NULL);
86da71b5
JHS
106 if (err < 0)
107 return err;
108
109 if (!tb[TCA_SKBMOD_PARMS])
110 return -EINVAL;
111
112 if (tb[TCA_SKBMOD_DMAC]) {
113 daddr = nla_data(tb[TCA_SKBMOD_DMAC]);
114 lflags |= SKBMOD_F_DMAC;
115 }
116
117 if (tb[TCA_SKBMOD_SMAC]) {
118 saddr = nla_data(tb[TCA_SKBMOD_SMAC]);
119 lflags |= SKBMOD_F_SMAC;
120 }
121
122 if (tb[TCA_SKBMOD_ETYPE]) {
123 eth_type = nla_get_u16(tb[TCA_SKBMOD_ETYPE]);
124 lflags |= SKBMOD_F_ETYPE;
125 }
126
127 parm = nla_data(tb[TCA_SKBMOD_PARMS]);
128 if (parm->flags & SKBMOD_F_SWAPMAC)
129 lflags = SKBMOD_F_SWAPMAC;
130
65a206c0 131 exists = tcf_idr_check(tn, parm->index, a, bind);
86da71b5
JHS
132 if (exists && bind)
133 return 0;
134
a52956df
RM
135 if (!lflags) {
136 if (exists)
137 tcf_idr_release(*a, bind);
86da71b5 138 return -EINVAL;
a52956df 139 }
86da71b5
JHS
140
141 if (!exists) {
65a206c0
CM
142 ret = tcf_idr_create(tn, parm->index, est, a,
143 &act_skbmod_ops, bind, true);
86da71b5
JHS
144 if (ret)
145 return ret;
146
147 ret = ACT_P_CREATED;
4e8ddd7f 148 } else if (!ovr) {
65a206c0 149 tcf_idr_release(*a, bind);
4e8ddd7f 150 return -EEXIST;
86da71b5
JHS
151 }
152
153 d = to_skbmod(*a);
154
155 ASSERT_RTNL();
156 p = kzalloc(sizeof(struct tcf_skbmod_params), GFP_KERNEL);
157 if (unlikely(!p)) {
4e8ddd7f 158 tcf_idr_release(*a, bind);
86da71b5
JHS
159 return -ENOMEM;
160 }
161
162 p->flags = lflags;
163 d->tcf_action = parm->action;
164
165 p_old = rtnl_dereference(d->skbmod_p);
166
167 if (ovr)
168 spin_lock_bh(&d->tcf_lock);
169
170 if (lflags & SKBMOD_F_DMAC)
171 ether_addr_copy(p->eth_dst, daddr);
172 if (lflags & SKBMOD_F_SMAC)
173 ether_addr_copy(p->eth_src, saddr);
174 if (lflags & SKBMOD_F_ETYPE)
175 p->eth_type = htons(eth_type);
176
177 rcu_assign_pointer(d->skbmod_p, p);
178 if (ovr)
179 spin_unlock_bh(&d->tcf_lock);
180
181 if (p_old)
182 kfree_rcu(p_old, rcu);
183
184 if (ret == ACT_P_CREATED)
65a206c0 185 tcf_idr_insert(tn, *a);
86da71b5
JHS
186 return ret;
187}
188
9a63b255 189static void tcf_skbmod_cleanup(struct tc_action *a)
86da71b5
JHS
190{
191 struct tcf_skbmod *d = to_skbmod(a);
192 struct tcf_skbmod_params *p;
193
194 p = rcu_dereference_protected(d->skbmod_p, 1);
2d433610
DC
195 if (p)
196 kfree_rcu(p, rcu);
86da71b5
JHS
197}
198
199static int tcf_skbmod_dump(struct sk_buff *skb, struct tc_action *a,
200 int bind, int ref)
201{
202 struct tcf_skbmod *d = to_skbmod(a);
203 unsigned char *b = skb_tail_pointer(skb);
204 struct tcf_skbmod_params *p = rtnl_dereference(d->skbmod_p);
205 struct tc_skbmod opt = {
206 .index = d->tcf_index,
036bb443
VB
207 .refcnt = refcount_read(&d->tcf_refcnt) - ref,
208 .bindcnt = atomic_read(&d->tcf_bindcnt) - bind,
86da71b5
JHS
209 .action = d->tcf_action,
210 };
211 struct tcf_t t;
212
213 opt.flags = p->flags;
214 if (nla_put(skb, TCA_SKBMOD_PARMS, sizeof(opt), &opt))
215 goto nla_put_failure;
216 if ((p->flags & SKBMOD_F_DMAC) &&
217 nla_put(skb, TCA_SKBMOD_DMAC, ETH_ALEN, p->eth_dst))
218 goto nla_put_failure;
219 if ((p->flags & SKBMOD_F_SMAC) &&
220 nla_put(skb, TCA_SKBMOD_SMAC, ETH_ALEN, p->eth_src))
221 goto nla_put_failure;
222 if ((p->flags & SKBMOD_F_ETYPE) &&
223 nla_put_u16(skb, TCA_SKBMOD_ETYPE, ntohs(p->eth_type)))
224 goto nla_put_failure;
225
226 tcf_tm_dump(&t, &d->tcf_tm);
227 if (nla_put_64bit(skb, TCA_SKBMOD_TM, sizeof(t), &t, TCA_SKBMOD_PAD))
228 goto nla_put_failure;
229
230 return skb->len;
231nla_put_failure:
86da71b5
JHS
232 nlmsg_trim(skb, b);
233 return -1;
234}
235
236static int tcf_skbmod_walker(struct net *net, struct sk_buff *skb,
237 struct netlink_callback *cb, int type,
41780105
AA
238 const struct tc_action_ops *ops,
239 struct netlink_ext_ack *extack)
86da71b5
JHS
240{
241 struct tc_action_net *tn = net_generic(net, skbmod_net_id);
242
b3620145 243 return tcf_generic_walker(tn, skb, cb, type, ops, extack);
86da71b5
JHS
244}
245
331a9295
AA
246static int tcf_skbmod_search(struct net *net, struct tc_action **a, u32 index,
247 struct netlink_ext_ack *extack)
86da71b5
JHS
248{
249 struct tc_action_net *tn = net_generic(net, skbmod_net_id);
250
65a206c0 251 return tcf_idr_search(tn, a, index);
86da71b5
JHS
252}
253
b409074e
VB
254static int tcf_skbmod_delete(struct net *net, u32 index)
255{
256 struct tc_action_net *tn = net_generic(net, skbmod_net_id);
257
258 return tcf_idr_delete_index(tn, index);
259}
260
86da71b5
JHS
261static struct tc_action_ops act_skbmod_ops = {
262 .kind = "skbmod",
263 .type = TCA_ACT_SKBMOD,
264 .owner = THIS_MODULE,
265 .act = tcf_skbmod_run,
266 .dump = tcf_skbmod_dump,
267 .init = tcf_skbmod_init,
268 .cleanup = tcf_skbmod_cleanup,
269 .walk = tcf_skbmod_walker,
270 .lookup = tcf_skbmod_search,
b409074e 271 .delete = tcf_skbmod_delete,
86da71b5
JHS
272 .size = sizeof(struct tcf_skbmod),
273};
274
275static __net_init int skbmod_init_net(struct net *net)
276{
277 struct tc_action_net *tn = net_generic(net, skbmod_net_id);
278
c7e460ce 279 return tc_action_net_init(tn, &act_skbmod_ops);
86da71b5
JHS
280}
281
039af9c6 282static void __net_exit skbmod_exit_net(struct list_head *net_list)
86da71b5 283{
039af9c6 284 tc_action_net_exit(net_list, skbmod_net_id);
86da71b5
JHS
285}
286
287static struct pernet_operations skbmod_net_ops = {
288 .init = skbmod_init_net,
039af9c6 289 .exit_batch = skbmod_exit_net,
86da71b5
JHS
290 .id = &skbmod_net_id,
291 .size = sizeof(struct tc_action_net),
292};
293
294MODULE_AUTHOR("Jamal Hadi Salim, <jhs@mojatatu.com>");
295MODULE_DESCRIPTION("SKB data mod-ing");
296MODULE_LICENSE("GPL");
297
298static int __init skbmod_init_module(void)
299{
300 return tcf_register_action(&act_skbmod_ops, &skbmod_net_ops);
301}
302
303static void __exit skbmod_cleanup_module(void)
304{
305 tcf_unregister_action(&act_skbmod_ops, &skbmod_net_ops);
306}
307
308module_init(skbmod_init_module);
309module_exit(skbmod_cleanup_module);