1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * net/sched/act_sample.c - Packet sampling tc action 4 * Copyright (c) 2017 Yotam Gigi <yotamg@mellanox.com> 5 */ 6 7 #include <linux/types.h> 8 #include <linux/kernel.h> 9 #include <linux/string.h> 10 #include <linux/errno.h> 11 #include <linux/skbuff.h> 12 #include <linux/rtnetlink.h> 13 #include <linux/module.h> 14 #include <linux/init.h> 15 #include <linux/gfp.h> 16 #include <net/net_namespace.h> 17 #include <net/netlink.h> 18 #include <net/pkt_sched.h> 19 #include <linux/tc_act/tc_sample.h> 20 #include <net/tc_act/tc_sample.h> 21 #include <net/psample.h> 22 #include <net/pkt_cls.h> 23 #include <net/tc_wrapper.h> 24 25 #include <linux/if_arp.h> 26 27 static struct tc_action_ops act_sample_ops; 28 29 static const struct nla_policy sample_policy[TCA_SAMPLE_MAX + 1] = { 30 [TCA_SAMPLE_PARMS] = { .len = sizeof(struct tc_sample) }, 31 [TCA_SAMPLE_RATE] = { .type = NLA_U32 }, 32 [TCA_SAMPLE_TRUNC_SIZE] = { .type = NLA_U32 }, 33 [TCA_SAMPLE_PSAMPLE_GROUP] = { .type = NLA_U32 }, 34 }; 35 36 static int tcf_sample_init(struct net *net, struct nlattr *nla, 37 struct nlattr *est, struct tc_action **a, 38 struct tcf_proto *tp, 39 u32 flags, struct netlink_ext_ack *extack) 40 { 41 struct tc_action_net *tn = net_generic(net, act_sample_ops.net_id); 42 bool bind = flags & TCA_ACT_FLAGS_BIND; 43 struct nlattr *tb[TCA_SAMPLE_MAX + 1]; 44 struct psample_group *psample_group; 45 u32 psample_group_num, rate, index; 46 struct tcf_chain *goto_ch = NULL; 47 struct tc_sample *parm; 48 struct tcf_sample *s; 49 bool exists = false; 50 int ret, err; 51 52 if (!nla) 53 return -EINVAL; 54 ret = nla_parse_nested_deprecated(tb, TCA_SAMPLE_MAX, nla, 55 sample_policy, NULL); 56 if (ret < 0) 57 return ret; 58 59 if (!tb[TCA_SAMPLE_PARMS]) 60 return -EINVAL; 61 62 parm = nla_data(tb[TCA_SAMPLE_PARMS]); 63 index = parm->index; 64 err = tcf_idr_check_alloc(tn, &index, a, bind); 65 if (err < 0) 66 return err; 67 exists = err; 68 if (exists && bind) 69 return ACT_P_BOUND; 70 71 if (!exists) { 72 ret = tcf_idr_create(tn, index, est, a, 73 &act_sample_ops, bind, true, flags); 74 if (ret) { 75 tcf_idr_cleanup(tn, index); 76 return ret; 77 } 78 ret = ACT_P_CREATED; 79 } else if (!(flags & TCA_ACT_FLAGS_REPLACE)) { 80 tcf_idr_release(*a, bind); 81 return -EEXIST; 82 } 83 84 if (!tb[TCA_SAMPLE_RATE] || !tb[TCA_SAMPLE_PSAMPLE_GROUP]) { 85 NL_SET_ERR_MSG(extack, "sample rate and group are required"); 86 err = -EINVAL; 87 goto release_idr; 88 } 89 90 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack); 91 if (err < 0) 92 goto release_idr; 93 94 rate = nla_get_u32(tb[TCA_SAMPLE_RATE]); 95 if (!rate) { 96 NL_SET_ERR_MSG(extack, "invalid sample rate"); 97 err = -EINVAL; 98 goto put_chain; 99 } 100 psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]); 101 psample_group = psample_group_get(net, psample_group_num); 102 if (!psample_group) { 103 err = -ENOMEM; 104 goto put_chain; 105 } 106 107 s = to_sample(*a); 108 109 spin_lock_bh(&s->tcf_lock); 110 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch); 111 s->rate = rate; 112 s->psample_group_num = psample_group_num; 113 psample_group = rcu_replace_pointer(s->psample_group, psample_group, 114 lockdep_is_held(&s->tcf_lock)); 115 116 if (tb[TCA_SAMPLE_TRUNC_SIZE]) { 117 s->truncate = true; 118 s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]); 119 } 120 spin_unlock_bh(&s->tcf_lock); 121 122 if (psample_group) 123 psample_group_put(psample_group); 124 if (goto_ch) 125 tcf_chain_put_by_act(goto_ch); 126 127 return ret; 128 put_chain: 129 if (goto_ch) 130 tcf_chain_put_by_act(goto_ch); 131 release_idr: 132 tcf_idr_release(*a, bind); 133 return err; 134 } 135 136 static void tcf_sample_cleanup(struct tc_action *a) 137 { 138 struct tcf_sample *s = to_sample(a); 139 struct psample_group *psample_group; 140 141 /* last reference to action, no need to lock */ 142 psample_group = rcu_dereference_protected(s->psample_group, 1); 143 RCU_INIT_POINTER(s->psample_group, NULL); 144 if (psample_group) 145 psample_group_put(psample_group); 146 } 147 148 static bool tcf_sample_dev_ok_push(struct net_device *dev) 149 { 150 switch (dev->type) { 151 case ARPHRD_TUNNEL: 152 case ARPHRD_TUNNEL6: 153 case ARPHRD_SIT: 154 case ARPHRD_IPGRE: 155 case ARPHRD_IP6GRE: 156 case ARPHRD_VOID: 157 case ARPHRD_NONE: 158 return false; 159 default: 160 return true; 161 } 162 } 163 164 TC_INDIRECT_SCOPE int tcf_sample_act(struct sk_buff *skb, 165 const struct tc_action *a, 166 struct tcf_result *res) 167 { 168 struct tcf_sample *s = to_sample(a); 169 struct psample_group *psample_group; 170 u8 cookie_data[TC_COOKIE_MAX_SIZE]; 171 struct psample_metadata md = {}; 172 struct tc_cookie *user_cookie; 173 int retval; 174 175 tcf_lastuse_update(&s->tcf_tm); 176 bstats_update(this_cpu_ptr(s->common.cpu_bstats), skb); 177 retval = READ_ONCE(s->tcf_action); 178 179 psample_group = rcu_dereference_bh(s->psample_group); 180 181 /* randomly sample packets according to rate */ 182 if (psample_group && (get_random_u32_below(s->rate) == 0)) { 183 if (!skb_at_tc_ingress(skb)) { 184 md.in_ifindex = skb->skb_iif; 185 md.out_ifindex = skb->dev->ifindex; 186 } else { 187 md.in_ifindex = skb->dev->ifindex; 188 } 189 190 /* on ingress, the mac header gets popped, so push it back */ 191 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) 192 skb_push(skb, skb->mac_len); 193 194 rcu_read_lock(); 195 user_cookie = rcu_dereference(a->user_cookie); 196 if (user_cookie) { 197 memcpy(cookie_data, user_cookie->data, 198 user_cookie->len); 199 md.user_cookie = cookie_data; 200 md.user_cookie_len = user_cookie->len; 201 } 202 rcu_read_unlock(); 203 204 md.trunc_size = s->truncate ? s->trunc_size : skb->len; 205 psample_sample_packet(psample_group, skb, s->rate, &md); 206 207 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) 208 skb_pull(skb, skb->mac_len); 209 } 210 211 return retval; 212 } 213 214 static void tcf_sample_stats_update(struct tc_action *a, u64 bytes, u64 packets, 215 u64 drops, u64 lastuse, bool hw) 216 { 217 struct tcf_sample *s = to_sample(a); 218 struct tcf_t *tm = &s->tcf_tm; 219 220 tcf_action_update_stats(a, bytes, packets, drops, hw); 221 tm->lastuse = max_t(u64, tm->lastuse, lastuse); 222 } 223 224 static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a, 225 int bind, int ref) 226 { 227 unsigned char *b = skb_tail_pointer(skb); 228 struct tcf_sample *s = to_sample(a); 229 struct tc_sample opt = { 230 .index = s->tcf_index, 231 .refcnt = refcount_read(&s->tcf_refcnt) - ref, 232 .bindcnt = atomic_read(&s->tcf_bindcnt) - bind, 233 }; 234 struct tcf_t t; 235 236 spin_lock_bh(&s->tcf_lock); 237 opt.action = s->tcf_action; 238 if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt)) 239 goto nla_put_failure; 240 241 tcf_tm_dump(&t, &s->tcf_tm); 242 if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD)) 243 goto nla_put_failure; 244 245 if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate)) 246 goto nla_put_failure; 247 248 if (s->truncate) 249 if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size)) 250 goto nla_put_failure; 251 252 if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num)) 253 goto nla_put_failure; 254 spin_unlock_bh(&s->tcf_lock); 255 256 return skb->len; 257 258 nla_put_failure: 259 spin_unlock_bh(&s->tcf_lock); 260 nlmsg_trim(skb, b); 261 return -1; 262 } 263 264 static void tcf_psample_group_put(void *priv) 265 { 266 struct psample_group *group = priv; 267 268 psample_group_put(group); 269 } 270 271 static struct psample_group * 272 tcf_sample_get_group(const struct tc_action *a, 273 tc_action_priv_destructor *destructor) 274 { 275 struct tcf_sample *s = to_sample(a); 276 struct psample_group *group; 277 278 group = rcu_dereference_protected(s->psample_group, 279 lockdep_is_held(&s->tcf_lock)); 280 if (group) { 281 psample_group_take(group); 282 *destructor = tcf_psample_group_put; 283 } 284 285 return group; 286 } 287 288 static void tcf_offload_sample_get_group(struct flow_action_entry *entry, 289 const struct tc_action *act) 290 { 291 entry->sample.psample_group = 292 act->ops->get_psample_group(act, &entry->destructor); 293 entry->destructor_priv = entry->sample.psample_group; 294 } 295 296 static int tcf_sample_offload_act_setup(struct tc_action *act, void *entry_data, 297 u32 *index_inc, bool bind, 298 struct netlink_ext_ack *extack) 299 { 300 if (bind) { 301 struct flow_action_entry *entry = entry_data; 302 303 entry->id = FLOW_ACTION_SAMPLE; 304 entry->sample.trunc_size = tcf_sample_trunc_size(act); 305 entry->sample.truncate = tcf_sample_truncate(act); 306 entry->sample.rate = tcf_sample_rate(act); 307 tcf_offload_sample_get_group(entry, act); 308 *index_inc = 1; 309 } else { 310 struct flow_offload_action *fl_action = entry_data; 311 312 fl_action->id = FLOW_ACTION_SAMPLE; 313 } 314 315 return 0; 316 } 317 318 static struct tc_action_ops act_sample_ops = { 319 .kind = "sample", 320 .id = TCA_ID_SAMPLE, 321 .owner = THIS_MODULE, 322 .act = tcf_sample_act, 323 .stats_update = tcf_sample_stats_update, 324 .dump = tcf_sample_dump, 325 .init = tcf_sample_init, 326 .cleanup = tcf_sample_cleanup, 327 .get_psample_group = tcf_sample_get_group, 328 .offload_act_setup = tcf_sample_offload_act_setup, 329 .size = sizeof(struct tcf_sample), 330 }; 331 MODULE_ALIAS_NET_ACT("sample"); 332 333 static __net_init int sample_init_net(struct net *net) 334 { 335 struct tc_action_net *tn = net_generic(net, act_sample_ops.net_id); 336 337 return tc_action_net_init(net, tn, &act_sample_ops); 338 } 339 340 static void __net_exit sample_exit_net(struct list_head *net_list) 341 { 342 tc_action_net_exit(net_list, act_sample_ops.net_id); 343 } 344 345 static struct pernet_operations sample_net_ops = { 346 .init = sample_init_net, 347 .exit_batch = sample_exit_net, 348 .id = &act_sample_ops.net_id, 349 .size = sizeof(struct tc_action_net), 350 }; 351 352 static int __init sample_init_module(void) 353 { 354 return tcf_register_action(&act_sample_ops, &sample_net_ops); 355 } 356 357 static void __exit sample_cleanup_module(void) 358 { 359 tcf_unregister_action(&act_sample_ops, &sample_net_ops); 360 } 361 362 module_init(sample_init_module); 363 module_exit(sample_cleanup_module); 364 365 MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>"); 366 MODULE_DESCRIPTION("Packet sampling action"); 367 MODULE_LICENSE("GPL v2"); 368