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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
23static unsigned int skbmod_net_id;
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
40
41
42
43 err = skb_ensure_writable(skb, MAX_EDIT_LEN);
44 if (unlikely(err)) {
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];
69
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,
87 int ovr, int bind, struct netlink_ext_ack *extack)
88{
89 struct tc_action_net *tn = net_generic(net, skbmod_net_id);
90 struct nlattr *tb[TCA_SKBMOD_MAX + 1];
91 struct tcf_skbmod_params *p, *p_old;
92 struct tc_skbmod *parm;
93 struct tcf_skbmod *d;
94 bool exists = false;
95 u8 *daddr = NULL;
96 u8 *saddr = NULL;
97 u16 eth_type = 0;
98 u32 lflags = 0;
99 int ret = 0, err;
100
101 if (!nla)
102 return -EINVAL;
103
104 err = nla_parse_nested(tb, TCA_SKBMOD_MAX, nla, skbmod_policy, NULL);
105 if (err < 0)
106 return err;
107
108 if (!tb[TCA_SKBMOD_PARMS])
109 return -EINVAL;
110
111 if (tb[TCA_SKBMOD_DMAC]) {
112 daddr = nla_data(tb[TCA_SKBMOD_DMAC]);
113 lflags |= SKBMOD_F_DMAC;
114 }
115
116 if (tb[TCA_SKBMOD_SMAC]) {
117 saddr = nla_data(tb[TCA_SKBMOD_SMAC]);
118 lflags |= SKBMOD_F_SMAC;
119 }
120
121 if (tb[TCA_SKBMOD_ETYPE]) {
122 eth_type = nla_get_u16(tb[TCA_SKBMOD_ETYPE]);
123 lflags |= SKBMOD_F_ETYPE;
124 }
125
126 parm = nla_data(tb[TCA_SKBMOD_PARMS]);
127 if (parm->flags & SKBMOD_F_SWAPMAC)
128 lflags = SKBMOD_F_SWAPMAC;
129
130 exists = tcf_idr_check(tn, parm->index, a, bind);
131 if (exists && bind)
132 return 0;
133
134 if (!lflags) {
135 if (exists)
136 tcf_idr_release(*a, bind);
137 return -EINVAL;
138 }
139
140 if (!exists) {
141 ret = tcf_idr_create(tn, parm->index, est, a,
142 &act_skbmod_ops, bind, true);
143 if (ret)
144 return ret;
145
146 ret = ACT_P_CREATED;
147 } else {
148 tcf_idr_release(*a, bind);
149 if (!ovr)
150 return -EEXIST;
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)) {
158 if (ret == ACT_P_CREATED)
159 tcf_idr_release(*a, bind);
160 return -ENOMEM;
161 }
162
163 p->flags = lflags;
164 d->tcf_action = parm->action;
165
166 p_old = rtnl_dereference(d->skbmod_p);
167
168 if (ovr)
169 spin_lock_bh(&d->tcf_lock);
170
171 if (lflags & SKBMOD_F_DMAC)
172 ether_addr_copy(p->eth_dst, daddr);
173 if (lflags & SKBMOD_F_SMAC)
174 ether_addr_copy(p->eth_src, saddr);
175 if (lflags & SKBMOD_F_ETYPE)
176 p->eth_type = htons(eth_type);
177
178 rcu_assign_pointer(d->skbmod_p, p);
179 if (ovr)
180 spin_unlock_bh(&d->tcf_lock);
181
182 if (p_old)
183 kfree_rcu(p_old, rcu);
184
185 if (ret == ACT_P_CREATED)
186 tcf_idr_insert(tn, *a);
187 return ret;
188}
189
190static void tcf_skbmod_cleanup(struct tc_action *a)
191{
192 struct tcf_skbmod *d = to_skbmod(a);
193 struct tcf_skbmod_params *p;
194
195 p = rcu_dereference_protected(d->skbmod_p, 1);
196 if (p)
197 kfree_rcu(p, rcu);
198}
199
200static int tcf_skbmod_dump(struct sk_buff *skb, struct tc_action *a,
201 int bind, int ref)
202{
203 struct tcf_skbmod *d = to_skbmod(a);
204 unsigned char *b = skb_tail_pointer(skb);
205 struct tcf_skbmod_params *p = rtnl_dereference(d->skbmod_p);
206 struct tc_skbmod opt = {
207 .index = d->tcf_index,
208 .refcnt = d->tcf_refcnt - ref,
209 .bindcnt = d->tcf_bindcnt - bind,
210 .action = d->tcf_action,
211 };
212 struct tcf_t t;
213
214 opt.flags = p->flags;
215 if (nla_put(skb, TCA_SKBMOD_PARMS, sizeof(opt), &opt))
216 goto nla_put_failure;
217 if ((p->flags & SKBMOD_F_DMAC) &&
218 nla_put(skb, TCA_SKBMOD_DMAC, ETH_ALEN, p->eth_dst))
219 goto nla_put_failure;
220 if ((p->flags & SKBMOD_F_SMAC) &&
221 nla_put(skb, TCA_SKBMOD_SMAC, ETH_ALEN, p->eth_src))
222 goto nla_put_failure;
223 if ((p->flags & SKBMOD_F_ETYPE) &&
224 nla_put_u16(skb, TCA_SKBMOD_ETYPE, ntohs(p->eth_type)))
225 goto nla_put_failure;
226
227 tcf_tm_dump(&t, &d->tcf_tm);
228 if (nla_put_64bit(skb, TCA_SKBMOD_TM, sizeof(t), &t, TCA_SKBMOD_PAD))
229 goto nla_put_failure;
230
231 return skb->len;
232nla_put_failure:
233 nlmsg_trim(skb, b);
234 return -1;
235}
236
237static int tcf_skbmod_walker(struct net *net, struct sk_buff *skb,
238 struct netlink_callback *cb, int type,
239 const struct tc_action_ops *ops,
240 struct netlink_ext_ack *extack)
241{
242 struct tc_action_net *tn = net_generic(net, skbmod_net_id);
243
244 return tcf_generic_walker(tn, skb, cb, type, ops, extack);
245}
246
247static int tcf_skbmod_search(struct net *net, struct tc_action **a, u32 index,
248 struct netlink_ext_ack *extack)
249{
250 struct tc_action_net *tn = net_generic(net, skbmod_net_id);
251
252 return tcf_idr_search(tn, a, index);
253}
254
255static struct tc_action_ops act_skbmod_ops = {
256 .kind = "skbmod",
257 .type = TCA_ACT_SKBMOD,
258 .owner = THIS_MODULE,
259 .act = tcf_skbmod_run,
260 .dump = tcf_skbmod_dump,
261 .init = tcf_skbmod_init,
262 .cleanup = tcf_skbmod_cleanup,
263 .walk = tcf_skbmod_walker,
264 .lookup = tcf_skbmod_search,
265 .size = sizeof(struct tcf_skbmod),
266};
267
268static __net_init int skbmod_init_net(struct net *net)
269{
270 struct tc_action_net *tn = net_generic(net, skbmod_net_id);
271
272 return tc_action_net_init(tn, &act_skbmod_ops);
273}
274
275static void __net_exit skbmod_exit_net(struct list_head *net_list)
276{
277 tc_action_net_exit(net_list, skbmod_net_id);
278}
279
280static struct pernet_operations skbmod_net_ops = {
281 .init = skbmod_init_net,
282 .exit_batch = skbmod_exit_net,
283 .id = &skbmod_net_id,
284 .size = sizeof(struct tc_action_net),
285};
286
287MODULE_AUTHOR("Jamal Hadi Salim, <jhs@mojatatu.com>");
288MODULE_DESCRIPTION("SKB data mod-ing");
289MODULE_LICENSE("GPL");
290
291static int __init skbmod_init_module(void)
292{
293 return tcf_register_action(&act_skbmod_ops, &skbmod_net_ops);
294}
295
296static void __exit skbmod_cleanup_module(void)
297{
298 tcf_unregister_action(&act_skbmod_ops, &skbmod_net_ops);
299}
300
301module_init(skbmod_init_module);
302module_exit(skbmod_cleanup_module);
303
