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 if (!tb[TCA_SAMPLE_PARMS] || !tb[TCA_SAMPLE_RATE] || 59 !tb[TCA_SAMPLE_PSAMPLE_GROUP]) 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 0; 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 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack); 84 if (err < 0) 85 goto release_idr; 86 87 rate = nla_get_u32(tb[TCA_SAMPLE_RATE]); 88 if (!rate) { 89 NL_SET_ERR_MSG(extack, "invalid sample rate"); 90 err = -EINVAL; 91 goto put_chain; 92 } 93 psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]); 94 psample_group = psample_group_get(net, psample_group_num); 95 if (!psample_group) { 96 err = -ENOMEM; 97 goto put_chain; 98 } 99 100 s = to_sample(*a); 101 102 spin_lock_bh(&s->tcf_lock); 103 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch); 104 s->rate = rate; 105 s->psample_group_num = psample_group_num; 106 psample_group = rcu_replace_pointer(s->psample_group, psample_group, 107 lockdep_is_held(&s->tcf_lock)); 108 109 if (tb[TCA_SAMPLE_TRUNC_SIZE]) { 110 s->truncate = true; 111 s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]); 112 } 113 spin_unlock_bh(&s->tcf_lock); 114 115 if (psample_group) 116 psample_group_put(psample_group); 117 if (goto_ch) 118 tcf_chain_put_by_act(goto_ch); 119 120 return ret; 121 put_chain: 122 if (goto_ch) 123 tcf_chain_put_by_act(goto_ch); 124 release_idr: 125 tcf_idr_release(*a, bind); 126 return err; 127 } 128 129 static void tcf_sample_cleanup(struct tc_action *a) 130 { 131 struct tcf_sample *s = to_sample(a); 132 struct psample_group *psample_group; 133 134 /* last reference to action, no need to lock */ 135 psample_group = rcu_dereference_protected(s->psample_group, 1); 136 RCU_INIT_POINTER(s->psample_group, NULL); 137 if (psample_group) 138 psample_group_put(psample_group); 139 } 140 141 static bool tcf_sample_dev_ok_push(struct net_device *dev) 142 { 143 switch (dev->type) { 144 case ARPHRD_TUNNEL: 145 case ARPHRD_TUNNEL6: 146 case ARPHRD_SIT: 147 case ARPHRD_IPGRE: 148 case ARPHRD_IP6GRE: 149 case ARPHRD_VOID: 150 case ARPHRD_NONE: 151 return false; 152 default: 153 return true; 154 } 155 } 156 157 TC_INDIRECT_SCOPE int tcf_sample_act(struct sk_buff *skb, 158 const struct tc_action *a, 159 struct tcf_result *res) 160 { 161 struct tcf_sample *s = to_sample(a); 162 struct psample_group *psample_group; 163 struct psample_metadata md = {}; 164 int retval; 165 166 tcf_lastuse_update(&s->tcf_tm); 167 bstats_update(this_cpu_ptr(s->common.cpu_bstats), skb); 168 retval = READ_ONCE(s->tcf_action); 169 170 psample_group = rcu_dereference_bh(s->psample_group); 171 172 /* randomly sample packets according to rate */ 173 if (psample_group && (get_random_u32_below(s->rate) == 0)) { 174 if (!skb_at_tc_ingress(skb)) { 175 md.in_ifindex = skb->skb_iif; 176 md.out_ifindex = skb->dev->ifindex; 177 } else { 178 md.in_ifindex = skb->dev->ifindex; 179 } 180 181 /* on ingress, the mac header gets popped, so push it back */ 182 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) 183 skb_push(skb, skb->mac_len); 184 185 md.trunc_size = s->truncate ? s->trunc_size : skb->len; 186 psample_sample_packet(psample_group, skb, s->rate, &md); 187 188 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) 189 skb_pull(skb, skb->mac_len); 190 } 191 192 return retval; 193 } 194 195 static void tcf_sample_stats_update(struct tc_action *a, u64 bytes, u64 packets, 196 u64 drops, u64 lastuse, bool hw) 197 { 198 struct tcf_sample *s = to_sample(a); 199 struct tcf_t *tm = &s->tcf_tm; 200 201 tcf_action_update_stats(a, bytes, packets, drops, hw); 202 tm->lastuse = max_t(u64, tm->lastuse, lastuse); 203 } 204 205 static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a, 206 int bind, int ref) 207 { 208 unsigned char *b = skb_tail_pointer(skb); 209 struct tcf_sample *s = to_sample(a); 210 struct tc_sample opt = { 211 .index = s->tcf_index, 212 .refcnt = refcount_read(&s->tcf_refcnt) - ref, 213 .bindcnt = atomic_read(&s->tcf_bindcnt) - bind, 214 }; 215 struct tcf_t t; 216 217 spin_lock_bh(&s->tcf_lock); 218 opt.action = s->tcf_action; 219 if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt)) 220 goto nla_put_failure; 221 222 tcf_tm_dump(&t, &s->tcf_tm); 223 if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD)) 224 goto nla_put_failure; 225 226 if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate)) 227 goto nla_put_failure; 228 229 if (s->truncate) 230 if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size)) 231 goto nla_put_failure; 232 233 if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num)) 234 goto nla_put_failure; 235 spin_unlock_bh(&s->tcf_lock); 236 237 return skb->len; 238 239 nla_put_failure: 240 spin_unlock_bh(&s->tcf_lock); 241 nlmsg_trim(skb, b); 242 return -1; 243 } 244 245 static void tcf_psample_group_put(void *priv) 246 { 247 struct psample_group *group = priv; 248 249 psample_group_put(group); 250 } 251 252 static struct psample_group * 253 tcf_sample_get_group(const struct tc_action *a, 254 tc_action_priv_destructor *destructor) 255 { 256 struct tcf_sample *s = to_sample(a); 257 struct psample_group *group; 258 259 group = rcu_dereference_protected(s->psample_group, 260 lockdep_is_held(&s->tcf_lock)); 261 if (group) { 262 psample_group_take(group); 263 *destructor = tcf_psample_group_put; 264 } 265 266 return group; 267 } 268 269 static void tcf_offload_sample_get_group(struct flow_action_entry *entry, 270 const struct tc_action *act) 271 { 272 entry->sample.psample_group = 273 act->ops->get_psample_group(act, &entry->destructor); 274 entry->destructor_priv = entry->sample.psample_group; 275 } 276 277 static int tcf_sample_offload_act_setup(struct tc_action *act, void *entry_data, 278 u32 *index_inc, bool bind, 279 struct netlink_ext_ack *extack) 280 { 281 if (bind) { 282 struct flow_action_entry *entry = entry_data; 283 284 entry->id = FLOW_ACTION_SAMPLE; 285 entry->sample.trunc_size = tcf_sample_trunc_size(act); 286 entry->sample.truncate = tcf_sample_truncate(act); 287 entry->sample.rate = tcf_sample_rate(act); 288 tcf_offload_sample_get_group(entry, act); 289 *index_inc = 1; 290 } else { 291 struct flow_offload_action *fl_action = entry_data; 292 293 fl_action->id = FLOW_ACTION_SAMPLE; 294 } 295 296 return 0; 297 } 298 299 static struct tc_action_ops act_sample_ops = { 300 .kind = "sample", 301 .id = TCA_ID_SAMPLE, 302 .owner = THIS_MODULE, 303 .act = tcf_sample_act, 304 .stats_update = tcf_sample_stats_update, 305 .dump = tcf_sample_dump, 306 .init = tcf_sample_init, 307 .cleanup = tcf_sample_cleanup, 308 .get_psample_group = tcf_sample_get_group, 309 .offload_act_setup = tcf_sample_offload_act_setup, 310 .size = sizeof(struct tcf_sample), 311 }; 312 313 static __net_init int sample_init_net(struct net *net) 314 { 315 struct tc_action_net *tn = net_generic(net, act_sample_ops.net_id); 316 317 return tc_action_net_init(net, tn, &act_sample_ops); 318 } 319 320 static void __net_exit sample_exit_net(struct list_head *net_list) 321 { 322 tc_action_net_exit(net_list, act_sample_ops.net_id); 323 } 324 325 static struct pernet_operations sample_net_ops = { 326 .init = sample_init_net, 327 .exit_batch = sample_exit_net, 328 .id = &act_sample_ops.net_id, 329 .size = sizeof(struct tc_action_net), 330 }; 331 332 static int __init sample_init_module(void) 333 { 334 return tcf_register_action(&act_sample_ops, &sample_net_ops); 335 } 336 337 static void __exit sample_cleanup_module(void) 338 { 339 tcf_unregister_action(&act_sample_ops, &sample_net_ops); 340 } 341 342 module_init(sample_init_module); 343 module_exit(sample_cleanup_module); 344 345 MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>"); 346 MODULE_DESCRIPTION("Packet sampling action"); 347 MODULE_LICENSE("GPL v2"); 348