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