2 * net/sched/act_skbmod.c skb data modifier
4 * Copyright (c) 2016 Jamal Hadi Salim <jhs@mojatatu.com>
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.
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 #include <net/pkt_cls.h>
21 #include <linux/tc_act/tc_skbmod.h>
22 #include <net/tc_act/tc_skbmod.h>
24 static unsigned int skbmod_net_id;
25 static struct tc_action_ops act_skbmod_ops;
27 #define MAX_EDIT_LEN ETH_HLEN
28 static int tcf_skbmod_act(struct sk_buff *skb, const struct tc_action *a,
29 struct tcf_result *res)
31 struct tcf_skbmod *d = to_skbmod(a);
33 struct tcf_skbmod_params *p;
37 tcf_lastuse_update(&d->tcf_tm);
38 bstats_cpu_update(this_cpu_ptr(d->common.cpu_bstats), skb);
40 /* XXX: if you are going to edit more fields beyond ethernet header
41 * (example when you add IP header replacement or vlan swap)
42 * then MAX_EDIT_LEN needs to change appropriately
44 err = skb_ensure_writable(skb, MAX_EDIT_LEN);
45 if (unlikely(err)) /* best policy is to drop on the floor */
48 action = READ_ONCE(d->tcf_action);
49 if (unlikely(action == TC_ACT_SHOT))
52 p = rcu_dereference_bh(d->skbmod_p);
54 if (flags & SKBMOD_F_DMAC)
55 ether_addr_copy(eth_hdr(skb)->h_dest, p->eth_dst);
56 if (flags & SKBMOD_F_SMAC)
57 ether_addr_copy(eth_hdr(skb)->h_source, p->eth_src);
58 if (flags & SKBMOD_F_ETYPE)
59 eth_hdr(skb)->h_proto = p->eth_type;
61 if (flags & SKBMOD_F_SWAPMAC) {
62 u16 tmpaddr[ETH_ALEN / 2]; /* ether_addr_copy() requirement */
63 /*XXX: I am sure we can come up with more efficient swapping*/
64 ether_addr_copy((u8 *)tmpaddr, eth_hdr(skb)->h_dest);
65 ether_addr_copy(eth_hdr(skb)->h_dest, eth_hdr(skb)->h_source);
66 ether_addr_copy(eth_hdr(skb)->h_source, (u8 *)tmpaddr);
72 qstats_overlimit_inc(this_cpu_ptr(d->common.cpu_qstats));
76 static const struct nla_policy skbmod_policy[TCA_SKBMOD_MAX + 1] = {
77 [TCA_SKBMOD_PARMS] = { .len = sizeof(struct tc_skbmod) },
78 [TCA_SKBMOD_DMAC] = { .len = ETH_ALEN },
79 [TCA_SKBMOD_SMAC] = { .len = ETH_ALEN },
80 [TCA_SKBMOD_ETYPE] = { .type = NLA_U16 },
83 static int tcf_skbmod_init(struct net *net, struct nlattr *nla,
84 struct nlattr *est, struct tc_action **a,
85 int ovr, int bind, bool rtnl_held,
87 struct netlink_ext_ack *extack)
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 tcf_chain *goto_ch = NULL;
93 struct tc_skbmod *parm;
105 err = nla_parse_nested(tb, TCA_SKBMOD_MAX, nla, skbmod_policy, NULL);
109 if (!tb[TCA_SKBMOD_PARMS])
112 if (tb[TCA_SKBMOD_DMAC]) {
113 daddr = nla_data(tb[TCA_SKBMOD_DMAC]);
114 lflags |= SKBMOD_F_DMAC;
117 if (tb[TCA_SKBMOD_SMAC]) {
118 saddr = nla_data(tb[TCA_SKBMOD_SMAC]);
119 lflags |= SKBMOD_F_SMAC;
122 if (tb[TCA_SKBMOD_ETYPE]) {
123 eth_type = nla_get_u16(tb[TCA_SKBMOD_ETYPE]);
124 lflags |= SKBMOD_F_ETYPE;
127 parm = nla_data(tb[TCA_SKBMOD_PARMS]);
128 if (parm->flags & SKBMOD_F_SWAPMAC)
129 lflags = SKBMOD_F_SWAPMAC;
131 err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
140 tcf_idr_release(*a, bind);
142 tcf_idr_cleanup(tn, parm->index);
147 ret = tcf_idr_create(tn, parm->index, est, a,
148 &act_skbmod_ops, bind, true);
150 tcf_idr_cleanup(tn, parm->index);
156 tcf_idr_release(*a, bind);
159 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
165 p = kzalloc(sizeof(struct tcf_skbmod_params), GFP_KERNEL);
174 spin_lock_bh(&d->tcf_lock);
175 /* Protected by tcf_lock if overwriting existing action. */
176 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
177 p_old = rcu_dereference_protected(d->skbmod_p, 1);
179 if (lflags & SKBMOD_F_DMAC)
180 ether_addr_copy(p->eth_dst, daddr);
181 if (lflags & SKBMOD_F_SMAC)
182 ether_addr_copy(p->eth_src, saddr);
183 if (lflags & SKBMOD_F_ETYPE)
184 p->eth_type = htons(eth_type);
186 rcu_assign_pointer(d->skbmod_p, p);
188 spin_unlock_bh(&d->tcf_lock);
191 kfree_rcu(p_old, rcu);
193 tcf_chain_put_by_act(goto_ch);
195 if (ret == ACT_P_CREATED)
196 tcf_idr_insert(tn, *a);
200 tcf_chain_put_by_act(goto_ch);
202 tcf_idr_release(*a, bind);
206 static void tcf_skbmod_cleanup(struct tc_action *a)
208 struct tcf_skbmod *d = to_skbmod(a);
209 struct tcf_skbmod_params *p;
211 p = rcu_dereference_protected(d->skbmod_p, 1);
216 static int tcf_skbmod_dump(struct sk_buff *skb, struct tc_action *a,
219 struct tcf_skbmod *d = to_skbmod(a);
220 unsigned char *b = skb_tail_pointer(skb);
221 struct tcf_skbmod_params *p;
222 struct tc_skbmod opt = {
223 .index = d->tcf_index,
224 .refcnt = refcount_read(&d->tcf_refcnt) - ref,
225 .bindcnt = atomic_read(&d->tcf_bindcnt) - bind,
229 spin_lock_bh(&d->tcf_lock);
230 opt.action = d->tcf_action;
231 p = rcu_dereference_protected(d->skbmod_p,
232 lockdep_is_held(&d->tcf_lock));
233 opt.flags = p->flags;
234 if (nla_put(skb, TCA_SKBMOD_PARMS, sizeof(opt), &opt))
235 goto nla_put_failure;
236 if ((p->flags & SKBMOD_F_DMAC) &&
237 nla_put(skb, TCA_SKBMOD_DMAC, ETH_ALEN, p->eth_dst))
238 goto nla_put_failure;
239 if ((p->flags & SKBMOD_F_SMAC) &&
240 nla_put(skb, TCA_SKBMOD_SMAC, ETH_ALEN, p->eth_src))
241 goto nla_put_failure;
242 if ((p->flags & SKBMOD_F_ETYPE) &&
243 nla_put_u16(skb, TCA_SKBMOD_ETYPE, ntohs(p->eth_type)))
244 goto nla_put_failure;
246 tcf_tm_dump(&t, &d->tcf_tm);
247 if (nla_put_64bit(skb, TCA_SKBMOD_TM, sizeof(t), &t, TCA_SKBMOD_PAD))
248 goto nla_put_failure;
250 spin_unlock_bh(&d->tcf_lock);
253 spin_unlock_bh(&d->tcf_lock);
258 static int tcf_skbmod_walker(struct net *net, struct sk_buff *skb,
259 struct netlink_callback *cb, int type,
260 const struct tc_action_ops *ops,
261 struct netlink_ext_ack *extack)
263 struct tc_action_net *tn = net_generic(net, skbmod_net_id);
265 return tcf_generic_walker(tn, skb, cb, type, ops, extack);
268 static int tcf_skbmod_search(struct net *net, struct tc_action **a, u32 index)
270 struct tc_action_net *tn = net_generic(net, skbmod_net_id);
272 return tcf_idr_search(tn, a, index);
275 static struct tc_action_ops act_skbmod_ops = {
277 .id = TCA_ACT_SKBMOD,
278 .owner = THIS_MODULE,
279 .act = tcf_skbmod_act,
280 .dump = tcf_skbmod_dump,
281 .init = tcf_skbmod_init,
282 .cleanup = tcf_skbmod_cleanup,
283 .walk = tcf_skbmod_walker,
284 .lookup = tcf_skbmod_search,
285 .size = sizeof(struct tcf_skbmod),
288 static __net_init int skbmod_init_net(struct net *net)
290 struct tc_action_net *tn = net_generic(net, skbmod_net_id);
292 return tc_action_net_init(tn, &act_skbmod_ops);
295 static void __net_exit skbmod_exit_net(struct list_head *net_list)
297 tc_action_net_exit(net_list, skbmod_net_id);
300 static struct pernet_operations skbmod_net_ops = {
301 .init = skbmod_init_net,
302 .exit_batch = skbmod_exit_net,
303 .id = &skbmod_net_id,
304 .size = sizeof(struct tc_action_net),
307 MODULE_AUTHOR("Jamal Hadi Salim, <jhs@mojatatu.com>");
308 MODULE_DESCRIPTION("SKB data mod-ing");
309 MODULE_LICENSE("GPL");
311 static int __init skbmod_init_module(void)
313 return tcf_register_action(&act_skbmod_ops, &skbmod_net_ops);
316 static void __exit skbmod_cleanup_module(void)
318 tcf_unregister_action(&act_skbmod_ops, &skbmod_net_ops);
321 module_init(skbmod_init_module);
322 module_exit(skbmod_cleanup_module);