Commit | Line | Data |
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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 | 23 | static unsigned int skbmod_net_id; |
86da71b5 JHS |
24 | static struct tc_action_ops act_skbmod_ops; |
25 | ||
26 | #define MAX_EDIT_LEN ETH_HLEN | |
353d2c25 | 27 | static int tcf_skbmod_act(struct sk_buff *skb, const struct tc_action *a, |
86da71b5 JHS |
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); | |
7fd4b288 PA |
44 | if (unlikely(err)) /* best policy is to drop on the floor */ |
45 | goto drop; | |
86da71b5 | 46 | |
86da71b5 | 47 | action = READ_ONCE(d->tcf_action); |
7fd4b288 PA |
48 | if (unlikely(action == TC_ACT_SHOT)) |
49 | goto drop; | |
86da71b5 | 50 | |
7fd4b288 | 51 | p = rcu_dereference_bh(d->skbmod_p); |
86da71b5 JHS |
52 | flags = p->flags; |
53 | if (flags & SKBMOD_F_DMAC) | |
54 | ether_addr_copy(eth_hdr(skb)->h_dest, p->eth_dst); | |
55 | if (flags & SKBMOD_F_SMAC) | |
56 | ether_addr_copy(eth_hdr(skb)->h_source, p->eth_src); | |
57 | if (flags & SKBMOD_F_ETYPE) | |
58 | eth_hdr(skb)->h_proto = p->eth_type; | |
86da71b5 JHS |
59 | |
60 | if (flags & SKBMOD_F_SWAPMAC) { | |
61 | u16 tmpaddr[ETH_ALEN / 2]; /* ether_addr_copy() requirement */ | |
62 | /*XXX: I am sure we can come up with more efficient swapping*/ | |
63 | ether_addr_copy((u8 *)tmpaddr, eth_hdr(skb)->h_dest); | |
64 | ether_addr_copy(eth_hdr(skb)->h_dest, eth_hdr(skb)->h_source); | |
65 | ether_addr_copy(eth_hdr(skb)->h_source, (u8 *)tmpaddr); | |
66 | } | |
67 | ||
68 | return action; | |
7fd4b288 PA |
69 | |
70 | drop: | |
71 | qstats_overlimit_inc(this_cpu_ptr(d->common.cpu_qstats)); | |
72 | return TC_ACT_SHOT; | |
86da71b5 JHS |
73 | } |
74 | ||
75 | static const struct nla_policy skbmod_policy[TCA_SKBMOD_MAX + 1] = { | |
76 | [TCA_SKBMOD_PARMS] = { .len = sizeof(struct tc_skbmod) }, | |
77 | [TCA_SKBMOD_DMAC] = { .len = ETH_ALEN }, | |
78 | [TCA_SKBMOD_SMAC] = { .len = ETH_ALEN }, | |
79 | [TCA_SKBMOD_ETYPE] = { .type = NLA_U16 }, | |
80 | }; | |
81 | ||
82 | static int tcf_skbmod_init(struct net *net, struct nlattr *nla, | |
83 | struct nlattr *est, struct tc_action **a, | |
789871bb | 84 | int ovr, int bind, bool rtnl_held, |
85d0966f | 85 | struct tcf_proto *tp, |
789871bb | 86 | struct netlink_ext_ack *extack) |
86da71b5 JHS |
87 | { |
88 | struct tc_action_net *tn = net_generic(net, skbmod_net_id); | |
89 | struct nlattr *tb[TCA_SKBMOD_MAX + 1]; | |
90 | struct tcf_skbmod_params *p, *p_old; | |
91 | struct tc_skbmod *parm; | |
92 | struct tcf_skbmod *d; | |
93 | bool exists = false; | |
94 | u8 *daddr = NULL; | |
95 | u8 *saddr = NULL; | |
96 | u16 eth_type = 0; | |
97 | u32 lflags = 0; | |
98 | int ret = 0, err; | |
99 | ||
100 | if (!nla) | |
101 | return -EINVAL; | |
102 | ||
fceb6435 | 103 | err = nla_parse_nested(tb, TCA_SKBMOD_MAX, nla, skbmod_policy, NULL); |
86da71b5 JHS |
104 | if (err < 0) |
105 | return err; | |
106 | ||
107 | if (!tb[TCA_SKBMOD_PARMS]) | |
108 | return -EINVAL; | |
109 | ||
110 | if (tb[TCA_SKBMOD_DMAC]) { | |
111 | daddr = nla_data(tb[TCA_SKBMOD_DMAC]); | |
112 | lflags |= SKBMOD_F_DMAC; | |
113 | } | |
114 | ||
115 | if (tb[TCA_SKBMOD_SMAC]) { | |
116 | saddr = nla_data(tb[TCA_SKBMOD_SMAC]); | |
117 | lflags |= SKBMOD_F_SMAC; | |
118 | } | |
119 | ||
120 | if (tb[TCA_SKBMOD_ETYPE]) { | |
121 | eth_type = nla_get_u16(tb[TCA_SKBMOD_ETYPE]); | |
122 | lflags |= SKBMOD_F_ETYPE; | |
123 | } | |
124 | ||
125 | parm = nla_data(tb[TCA_SKBMOD_PARMS]); | |
126 | if (parm->flags & SKBMOD_F_SWAPMAC) | |
127 | lflags = SKBMOD_F_SWAPMAC; | |
128 | ||
0190c1d4 VB |
129 | err = tcf_idr_check_alloc(tn, &parm->index, a, bind); |
130 | if (err < 0) | |
131 | return err; | |
132 | exists = err; | |
86da71b5 JHS |
133 | if (exists && bind) |
134 | return 0; | |
135 | ||
a52956df RM |
136 | if (!lflags) { |
137 | if (exists) | |
138 | tcf_idr_release(*a, bind); | |
0190c1d4 VB |
139 | else |
140 | tcf_idr_cleanup(tn, parm->index); | |
86da71b5 | 141 | return -EINVAL; |
a52956df | 142 | } |
86da71b5 JHS |
143 | |
144 | if (!exists) { | |
65a206c0 CM |
145 | ret = tcf_idr_create(tn, parm->index, est, a, |
146 | &act_skbmod_ops, bind, true); | |
0190c1d4 VB |
147 | if (ret) { |
148 | tcf_idr_cleanup(tn, parm->index); | |
86da71b5 | 149 | return ret; |
0190c1d4 | 150 | } |
86da71b5 JHS |
151 | |
152 | ret = ACT_P_CREATED; | |
4e8ddd7f | 153 | } else if (!ovr) { |
65a206c0 | 154 | tcf_idr_release(*a, bind); |
4e8ddd7f | 155 | return -EEXIST; |
86da71b5 JHS |
156 | } |
157 | ||
158 | d = to_skbmod(*a); | |
159 | ||
86da71b5 JHS |
160 | p = kzalloc(sizeof(struct tcf_skbmod_params), GFP_KERNEL); |
161 | if (unlikely(!p)) { | |
4e8ddd7f | 162 | tcf_idr_release(*a, bind); |
86da71b5 JHS |
163 | return -ENOMEM; |
164 | } | |
165 | ||
166 | p->flags = lflags; | |
167 | d->tcf_action = parm->action; | |
168 | ||
86da71b5 JHS |
169 | if (ovr) |
170 | spin_lock_bh(&d->tcf_lock); | |
c8814552 VB |
171 | /* Protected by tcf_lock if overwriting existing action. */ |
172 | p_old = rcu_dereference_protected(d->skbmod_p, 1); | |
86da71b5 JHS |
173 | |
174 | if (lflags & SKBMOD_F_DMAC) | |
175 | ether_addr_copy(p->eth_dst, daddr); | |
176 | if (lflags & SKBMOD_F_SMAC) | |
177 | ether_addr_copy(p->eth_src, saddr); | |
178 | if (lflags & SKBMOD_F_ETYPE) | |
179 | p->eth_type = htons(eth_type); | |
180 | ||
181 | rcu_assign_pointer(d->skbmod_p, p); | |
182 | if (ovr) | |
183 | spin_unlock_bh(&d->tcf_lock); | |
184 | ||
185 | if (p_old) | |
186 | kfree_rcu(p_old, rcu); | |
187 | ||
188 | if (ret == ACT_P_CREATED) | |
65a206c0 | 189 | tcf_idr_insert(tn, *a); |
86da71b5 JHS |
190 | return ret; |
191 | } | |
192 | ||
9a63b255 | 193 | static void tcf_skbmod_cleanup(struct tc_action *a) |
86da71b5 JHS |
194 | { |
195 | struct tcf_skbmod *d = to_skbmod(a); | |
196 | struct tcf_skbmod_params *p; | |
197 | ||
198 | p = rcu_dereference_protected(d->skbmod_p, 1); | |
2d433610 DC |
199 | if (p) |
200 | kfree_rcu(p, rcu); | |
86da71b5 JHS |
201 | } |
202 | ||
203 | static int tcf_skbmod_dump(struct sk_buff *skb, struct tc_action *a, | |
204 | int bind, int ref) | |
205 | { | |
206 | struct tcf_skbmod *d = to_skbmod(a); | |
207 | unsigned char *b = skb_tail_pointer(skb); | |
c8814552 | 208 | struct tcf_skbmod_params *p; |
86da71b5 JHS |
209 | struct tc_skbmod opt = { |
210 | .index = d->tcf_index, | |
036bb443 VB |
211 | .refcnt = refcount_read(&d->tcf_refcnt) - ref, |
212 | .bindcnt = atomic_read(&d->tcf_bindcnt) - bind, | |
86da71b5 JHS |
213 | }; |
214 | struct tcf_t t; | |
215 | ||
c8814552 VB |
216 | spin_lock_bh(&d->tcf_lock); |
217 | opt.action = d->tcf_action; | |
218 | p = rcu_dereference_protected(d->skbmod_p, | |
219 | lockdep_is_held(&d->tcf_lock)); | |
86da71b5 JHS |
220 | opt.flags = p->flags; |
221 | if (nla_put(skb, TCA_SKBMOD_PARMS, sizeof(opt), &opt)) | |
222 | goto nla_put_failure; | |
223 | if ((p->flags & SKBMOD_F_DMAC) && | |
224 | nla_put(skb, TCA_SKBMOD_DMAC, ETH_ALEN, p->eth_dst)) | |
225 | goto nla_put_failure; | |
226 | if ((p->flags & SKBMOD_F_SMAC) && | |
227 | nla_put(skb, TCA_SKBMOD_SMAC, ETH_ALEN, p->eth_src)) | |
228 | goto nla_put_failure; | |
229 | if ((p->flags & SKBMOD_F_ETYPE) && | |
230 | nla_put_u16(skb, TCA_SKBMOD_ETYPE, ntohs(p->eth_type))) | |
231 | goto nla_put_failure; | |
232 | ||
233 | tcf_tm_dump(&t, &d->tcf_tm); | |
234 | if (nla_put_64bit(skb, TCA_SKBMOD_TM, sizeof(t), &t, TCA_SKBMOD_PAD)) | |
235 | goto nla_put_failure; | |
236 | ||
c8814552 | 237 | spin_unlock_bh(&d->tcf_lock); |
86da71b5 JHS |
238 | return skb->len; |
239 | nla_put_failure: | |
c8814552 | 240 | spin_unlock_bh(&d->tcf_lock); |
86da71b5 JHS |
241 | nlmsg_trim(skb, b); |
242 | return -1; | |
243 | } | |
244 | ||
245 | static int tcf_skbmod_walker(struct net *net, struct sk_buff *skb, | |
246 | struct netlink_callback *cb, int type, | |
41780105 AA |
247 | const struct tc_action_ops *ops, |
248 | struct netlink_ext_ack *extack) | |
86da71b5 JHS |
249 | { |
250 | struct tc_action_net *tn = net_generic(net, skbmod_net_id); | |
251 | ||
b3620145 | 252 | return tcf_generic_walker(tn, skb, cb, type, ops, extack); |
86da71b5 JHS |
253 | } |
254 | ||
f061b48c | 255 | static int tcf_skbmod_search(struct net *net, struct tc_action **a, u32 index) |
86da71b5 JHS |
256 | { |
257 | struct tc_action_net *tn = net_generic(net, skbmod_net_id); | |
258 | ||
65a206c0 | 259 | return tcf_idr_search(tn, a, index); |
86da71b5 JHS |
260 | } |
261 | ||
262 | static struct tc_action_ops act_skbmod_ops = { | |
263 | .kind = "skbmod", | |
eddd2cf1 | 264 | .id = TCA_ACT_SKBMOD, |
86da71b5 | 265 | .owner = THIS_MODULE, |
353d2c25 | 266 | .act = tcf_skbmod_act, |
86da71b5 JHS |
267 | .dump = tcf_skbmod_dump, |
268 | .init = tcf_skbmod_init, | |
269 | .cleanup = tcf_skbmod_cleanup, | |
270 | .walk = tcf_skbmod_walker, | |
271 | .lookup = tcf_skbmod_search, | |
272 | .size = sizeof(struct tcf_skbmod), | |
273 | }; | |
274 | ||
275 | static __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 | 282 | static 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 | ||
287 | static 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 | ||
294 | MODULE_AUTHOR("Jamal Hadi Salim, <jhs@mojatatu.com>"); | |
295 | MODULE_DESCRIPTION("SKB data mod-ing"); | |
296 | MODULE_LICENSE("GPL"); | |
297 | ||
298 | static int __init skbmod_init_module(void) | |
299 | { | |
300 | return tcf_register_action(&act_skbmod_ops, &skbmod_net_ops); | |
301 | } | |
302 | ||
303 | static void __exit skbmod_cleanup_module(void) | |
304 | { | |
305 | tcf_unregister_action(&act_skbmod_ops, &skbmod_net_ops); | |
306 | } | |
307 | ||
308 | module_init(skbmod_init_module); | |
309 | module_exit(skbmod_cleanup_module); |