1 // SPDX-License-Identifier: GPL-2.0+
2 /* net/sched/act_ctinfo.c netfilter ctinfo connmark actions
3 *
4 * Copyright (c) 2019 Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
5 */
6
7 #include <linux/module.h>
8 #include <linux/init.h>
9 #include <linux/kernel.h>
10 #include <linux/skbuff.h>
11 #include <linux/rtnetlink.h>
12 #include <linux/pkt_cls.h>
13 #include <linux/ip.h>
14 #include <linux/ipv6.h>
15 #include <net/netlink.h>
16 #include <net/pkt_sched.h>
17 #include <net/act_api.h>
18 #include <net/pkt_cls.h>
19 #include <net/inet_ecn.h>
20 #include <uapi/linux/tc_act/tc_ctinfo.h>
21 #include <net/tc_act/tc_ctinfo.h>
22 #include <net/tc_wrapper.h>
23
24 #include <net/netfilter/nf_conntrack.h>
25 #include <net/netfilter/nf_conntrack_core.h>
26 #include <net/netfilter/nf_conntrack_ecache.h>
27 #include <net/netfilter/nf_conntrack_zones.h>
28
29 static struct tc_action_ops act_ctinfo_ops;
30
tcf_ctinfo_dscp_set(struct nf_conn * ct,struct tcf_ctinfo * ca,struct tcf_ctinfo_params * cp,struct sk_buff * skb,int wlen,int proto)31 static void tcf_ctinfo_dscp_set(struct nf_conn *ct, struct tcf_ctinfo *ca,
32 struct tcf_ctinfo_params *cp,
33 struct sk_buff *skb, int wlen, int proto)
34 {
35 u8 dscp, newdscp;
36
37 newdscp = (((READ_ONCE(ct->mark) & cp->dscpmask) >> cp->dscpmaskshift) << 2) &
38 ~INET_ECN_MASK;
39
40 switch (proto) {
41 case NFPROTO_IPV4:
42 dscp = ipv4_get_dsfield(ip_hdr(skb)) & ~INET_ECN_MASK;
43 if (dscp != newdscp) {
44 if (likely(!skb_try_make_writable(skb, wlen))) {
45 ipv4_change_dsfield(ip_hdr(skb),
46 INET_ECN_MASK,
47 newdscp);
48 atomic64_inc(&ca->stats_dscp_set);
49 } else {
50 atomic64_inc(&ca->stats_dscp_error);
51 }
52 }
53 break;
54 case NFPROTO_IPV6:
55 dscp = ipv6_get_dsfield(ipv6_hdr(skb)) & ~INET_ECN_MASK;
56 if (dscp != newdscp) {
57 if (likely(!skb_try_make_writable(skb, wlen))) {
58 ipv6_change_dsfield(ipv6_hdr(skb),
59 INET_ECN_MASK,
60 newdscp);
61 atomic64_inc(&ca->stats_dscp_set);
62 } else {
63 atomic64_inc(&ca->stats_dscp_error);
64 }
65 }
66 break;
67 default:
68 break;
69 }
70 }
71
tcf_ctinfo_cpmark_set(struct nf_conn * ct,struct tcf_ctinfo * ca,struct tcf_ctinfo_params * cp,struct sk_buff * skb)72 static void tcf_ctinfo_cpmark_set(struct nf_conn *ct, struct tcf_ctinfo *ca,
73 struct tcf_ctinfo_params *cp,
74 struct sk_buff *skb)
75 {
76 atomic64_inc(&ca->stats_cpmark_set);
77 skb->mark = READ_ONCE(ct->mark) & cp->cpmarkmask;
78 }
79
tcf_ctinfo_act(struct sk_buff * skb,const struct tc_action * a,struct tcf_result * res)80 TC_INDIRECT_SCOPE int tcf_ctinfo_act(struct sk_buff *skb,
81 const struct tc_action *a,
82 struct tcf_result *res)
83 {
84 const struct nf_conntrack_tuple_hash *thash = NULL;
85 struct tcf_ctinfo *ca = to_ctinfo(a);
86 struct nf_conntrack_tuple tuple;
87 struct nf_conntrack_zone zone;
88 enum ip_conntrack_info ctinfo;
89 struct tcf_ctinfo_params *cp;
90 struct nf_conn *ct;
91 int proto, wlen;
92
93 cp = rcu_dereference_bh(ca->params);
94
95 tcf_lastuse_update(&ca->tcf_tm);
96 tcf_action_update_bstats(&ca->common, skb);
97
98 wlen = skb_network_offset(skb);
99 switch (skb_protocol(skb, true)) {
100 case htons(ETH_P_IP):
101 wlen += sizeof(struct iphdr);
102 if (!pskb_may_pull(skb, wlen))
103 goto out;
104
105 proto = NFPROTO_IPV4;
106 break;
107 case htons(ETH_P_IPV6):
108 wlen += sizeof(struct ipv6hdr);
109 if (!pskb_may_pull(skb, wlen))
110 goto out;
111
112 proto = NFPROTO_IPV6;
113 break;
114 default:
115 goto out;
116 }
117
118 ct = nf_ct_get(skb, &ctinfo);
119 if (!ct) { /* look harder, usually ingress */
120 if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
121 proto, cp->net, &tuple))
122 goto out;
123 zone.id = cp->zone;
124 zone.dir = NF_CT_DEFAULT_ZONE_DIR;
125
126 thash = nf_conntrack_find_get(cp->net, &zone, &tuple);
127 if (!thash)
128 goto out;
129
130 ct = nf_ct_tuplehash_to_ctrack(thash);
131 }
132
133 if (cp->mode & CTINFO_MODE_DSCP)
134 if (!cp->dscpstatemask || (READ_ONCE(ct->mark) & cp->dscpstatemask))
135 tcf_ctinfo_dscp_set(ct, ca, cp, skb, wlen, proto);
136
137 if (cp->mode & CTINFO_MODE_CPMARK)
138 tcf_ctinfo_cpmark_set(ct, ca, cp, skb);
139
140 if (thash)
141 nf_ct_put(ct);
142 out:
143 return cp->action;
144 }
145
146 static const struct nla_policy ctinfo_policy[TCA_CTINFO_MAX + 1] = {
147 [TCA_CTINFO_ACT] =
148 NLA_POLICY_EXACT_LEN(sizeof(struct tc_ctinfo)),
149 [TCA_CTINFO_ZONE] = { .type = NLA_U16 },
150 [TCA_CTINFO_PARMS_DSCP_MASK] = { .type = NLA_U32 },
151 [TCA_CTINFO_PARMS_DSCP_STATEMASK] = { .type = NLA_U32 },
152 [TCA_CTINFO_PARMS_CPMARK_MASK] = { .type = NLA_U32 },
153 };
154
tcf_ctinfo_init(struct net * net,struct nlattr * nla,struct nlattr * est,struct tc_action ** a,struct tcf_proto * tp,u32 flags,struct netlink_ext_ack * extack)155 static int tcf_ctinfo_init(struct net *net, struct nlattr *nla,
156 struct nlattr *est, struct tc_action **a,
157 struct tcf_proto *tp, u32 flags,
158 struct netlink_ext_ack *extack)
159 {
160 struct tc_action_net *tn = net_generic(net, act_ctinfo_ops.net_id);
161 bool bind = flags & TCA_ACT_FLAGS_BIND;
162 u32 dscpmask = 0, dscpstatemask, index;
163 struct nlattr *tb[TCA_CTINFO_MAX + 1];
164 struct tcf_ctinfo_params *cp_new;
165 struct tcf_chain *goto_ch = NULL;
166 struct tc_ctinfo *actparm;
167 struct tcf_ctinfo *ci;
168 u8 dscpmaskshift;
169 int ret = 0, err;
170
171 if (!nla) {
172 NL_SET_ERR_MSG_MOD(extack, "ctinfo requires attributes to be passed");
173 return -EINVAL;
174 }
175
176 err = nla_parse_nested(tb, TCA_CTINFO_MAX, nla, ctinfo_policy, extack);
177 if (err < 0)
178 return err;
179
180 if (!tb[TCA_CTINFO_ACT]) {
181 NL_SET_ERR_MSG_MOD(extack,
182 "Missing required TCA_CTINFO_ACT attribute");
183 return -EINVAL;
184 }
185 actparm = nla_data(tb[TCA_CTINFO_ACT]);
186
187 /* do some basic validation here before dynamically allocating things */
188 /* that we would otherwise have to clean up. */
189 if (tb[TCA_CTINFO_PARMS_DSCP_MASK]) {
190 dscpmask = nla_get_u32(tb[TCA_CTINFO_PARMS_DSCP_MASK]);
191 /* need contiguous 6 bit mask */
192 dscpmaskshift = dscpmask ? __ffs(dscpmask) : 0;
193 if ((~0 & (dscpmask >> dscpmaskshift)) != 0x3f) {
194 NL_SET_ERR_MSG_ATTR(extack,
195 tb[TCA_CTINFO_PARMS_DSCP_MASK],
196 "dscp mask must be 6 contiguous bits");
197 return -EINVAL;
198 }
199 dscpstatemask =
200 nla_get_u32_default(tb[TCA_CTINFO_PARMS_DSCP_STATEMASK],
201 0);
202 /* mask & statemask must not overlap */
203 if (dscpmask & dscpstatemask) {
204 NL_SET_ERR_MSG_ATTR(extack,
205 tb[TCA_CTINFO_PARMS_DSCP_STATEMASK],
206 "dscp statemask must not overlap dscp mask");
207 return -EINVAL;
208 }
209 }
210
211 /* done the validation:now to the actual action allocation */
212 index = actparm->index;
213 err = tcf_idr_check_alloc(tn, &index, a, bind);
214 if (!err) {
215 ret = tcf_idr_create_from_flags(tn, index, est, a,
216 &act_ctinfo_ops, bind, flags);
217 if (ret) {
218 tcf_idr_cleanup(tn, index);
219 return ret;
220 }
221 ret = ACT_P_CREATED;
222 } else if (err > 0) {
223 if (bind) /* don't override defaults */
224 return ACT_P_BOUND;
225 if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
226 tcf_idr_release(*a, bind);
227 return -EEXIST;
228 }
229 } else {
230 return err;
231 }
232
233 err = tcf_action_check_ctrlact(actparm->action, tp, &goto_ch, extack);
234 if (err < 0)
235 goto release_idr;
236
237 ci = to_ctinfo(*a);
238
239 cp_new = kzalloc_obj(*cp_new);
240 if (unlikely(!cp_new)) {
241 err = -ENOMEM;
242 goto put_chain;
243 }
244
245 cp_new->net = net;
246 cp_new->zone = nla_get_u16_default(tb[TCA_CTINFO_ZONE], 0);
247 if (dscpmask) {
248 cp_new->dscpmask = dscpmask;
249 cp_new->dscpmaskshift = dscpmaskshift;
250 cp_new->dscpstatemask = dscpstatemask;
251 cp_new->mode |= CTINFO_MODE_DSCP;
252 }
253
254 if (tb[TCA_CTINFO_PARMS_CPMARK_MASK]) {
255 cp_new->cpmarkmask =
256 nla_get_u32(tb[TCA_CTINFO_PARMS_CPMARK_MASK]);
257 cp_new->mode |= CTINFO_MODE_CPMARK;
258 }
259
260 cp_new->action = actparm->action;
261
262 spin_lock_bh(&ci->tcf_lock);
263 goto_ch = tcf_action_set_ctrlact(*a, actparm->action, goto_ch);
264 cp_new = rcu_replace_pointer(ci->params, cp_new,
265 lockdep_is_held(&ci->tcf_lock));
266 spin_unlock_bh(&ci->tcf_lock);
267
268 if (goto_ch)
269 tcf_chain_put_by_act(goto_ch);
270 if (cp_new)
271 kfree_rcu(cp_new, rcu);
272
273 return ret;
274
275 put_chain:
276 if (goto_ch)
277 tcf_chain_put_by_act(goto_ch);
278 release_idr:
279 tcf_idr_release(*a, bind);
280 return err;
281 }
282
tcf_ctinfo_dump(struct sk_buff * skb,struct tc_action * a,int bind,int ref)283 static int tcf_ctinfo_dump(struct sk_buff *skb, struct tc_action *a,
284 int bind, int ref)
285 {
286 const struct tcf_ctinfo *ci = to_ctinfo(a);
287 unsigned char *b = skb_tail_pointer(skb);
288 const struct tcf_ctinfo_params *cp;
289 struct tc_ctinfo opt = {
290 .index = ci->tcf_index,
291 .refcnt = refcount_read(&ci->tcf_refcnt) - ref,
292 .bindcnt = atomic_read(&ci->tcf_bindcnt) - bind,
293 };
294 struct tcf_t t;
295
296 rcu_read_lock();
297 cp = rcu_dereference(ci->params);
298
299 tcf_tm_dump(&t, &ci->tcf_tm);
300 if (nla_put_64bit(skb, TCA_CTINFO_TM, sizeof(t), &t, TCA_CTINFO_PAD))
301 goto nla_put_failure;
302
303 opt.action = cp->action;
304 if (nla_put(skb, TCA_CTINFO_ACT, sizeof(opt), &opt))
305 goto nla_put_failure;
306
307 if (nla_put_u16(skb, TCA_CTINFO_ZONE, cp->zone))
308 goto nla_put_failure;
309
310 if (cp->mode & CTINFO_MODE_DSCP) {
311 if (nla_put_u32(skb, TCA_CTINFO_PARMS_DSCP_MASK,
312 cp->dscpmask))
313 goto nla_put_failure;
314 if (nla_put_u32(skb, TCA_CTINFO_PARMS_DSCP_STATEMASK,
315 cp->dscpstatemask))
316 goto nla_put_failure;
317 }
318
319 if (cp->mode & CTINFO_MODE_CPMARK) {
320 if (nla_put_u32(skb, TCA_CTINFO_PARMS_CPMARK_MASK,
321 cp->cpmarkmask))
322 goto nla_put_failure;
323 }
324
325 if (nla_put_u64_64bit(skb, TCA_CTINFO_STATS_DSCP_SET,
326 atomic64_read(&ci->stats_dscp_set),
327 TCA_CTINFO_PAD))
328 goto nla_put_failure;
329
330 if (nla_put_u64_64bit(skb, TCA_CTINFO_STATS_DSCP_ERROR,
331 atomic64_read(&ci->stats_dscp_error),
332 TCA_CTINFO_PAD))
333 goto nla_put_failure;
334
335 if (nla_put_u64_64bit(skb, TCA_CTINFO_STATS_CPMARK_SET,
336 atomic64_read(&ci->stats_cpmark_set),
337 TCA_CTINFO_PAD))
338 goto nla_put_failure;
339
340 rcu_read_unlock();
341 return skb->len;
342
343 nla_put_failure:
344 rcu_read_unlock();
345 nlmsg_trim(skb, b);
346 return -1;
347 }
348
tcf_ctinfo_cleanup(struct tc_action * a)349 static void tcf_ctinfo_cleanup(struct tc_action *a)
350 {
351 struct tcf_ctinfo *ci = to_ctinfo(a);
352 struct tcf_ctinfo_params *cp;
353
354 cp = rcu_dereference_protected(ci->params, 1);
355 if (cp)
356 kfree_rcu(cp, rcu);
357 }
358
359 static struct tc_action_ops act_ctinfo_ops = {
360 .kind = "ctinfo",
361 .id = TCA_ID_CTINFO,
362 .owner = THIS_MODULE,
363 .act = tcf_ctinfo_act,
364 .dump = tcf_ctinfo_dump,
365 .init = tcf_ctinfo_init,
366 .cleanup= tcf_ctinfo_cleanup,
367 .size = sizeof(struct tcf_ctinfo),
368 };
369 MODULE_ALIAS_NET_ACT("ctinfo");
370
ctinfo_init_net(struct net * net)371 static __net_init int ctinfo_init_net(struct net *net)
372 {
373 struct tc_action_net *tn = net_generic(net, act_ctinfo_ops.net_id);
374
375 return tc_action_net_init(net, tn, &act_ctinfo_ops);
376 }
377
ctinfo_exit_net(struct list_head * net_list)378 static void __net_exit ctinfo_exit_net(struct list_head *net_list)
379 {
380 tc_action_net_exit(net_list, act_ctinfo_ops.net_id);
381 }
382
383 static struct pernet_operations ctinfo_net_ops = {
384 .init = ctinfo_init_net,
385 .exit_batch = ctinfo_exit_net,
386 .id = &act_ctinfo_ops.net_id,
387 .size = sizeof(struct tc_action_net),
388 };
389
ctinfo_init_module(void)390 static int __init ctinfo_init_module(void)
391 {
392 return tcf_register_action(&act_ctinfo_ops, &ctinfo_net_ops);
393 }
394
ctinfo_cleanup_module(void)395 static void __exit ctinfo_cleanup_module(void)
396 {
397 tcf_unregister_action(&act_ctinfo_ops, &ctinfo_net_ops);
398 }
399
400 module_init(ctinfo_init_module);
401 module_exit(ctinfo_cleanup_module);
402 MODULE_AUTHOR("Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>");
403 MODULE_DESCRIPTION("Connection tracking mark actions");
404 MODULE_LICENSE("GPL");
405