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 24 #include <linux/if_arp.h> 25 26 static unsigned int sample_net_id; 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, sample_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, 0); 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 static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a, 158 struct tcf_result *res) 159 { 160 struct tcf_sample *s = to_sample(a); 161 struct psample_group *psample_group; 162 struct psample_metadata md = {}; 163 int retval; 164 165 tcf_lastuse_update(&s->tcf_tm); 166 bstats_cpu_update(this_cpu_ptr(s->common.cpu_bstats), skb); 167 retval = READ_ONCE(s->tcf_action); 168 169 psample_group = rcu_dereference_bh(s->psample_group); 170 171 /* randomly sample packets according to rate */ 172 if (psample_group && (prandom_u32() % s->rate == 0)) { 173 if (!skb_at_tc_ingress(skb)) { 174 md.in_ifindex = skb->skb_iif; 175 md.out_ifindex = skb->dev->ifindex; 176 } else { 177 md.in_ifindex = skb->dev->ifindex; 178 } 179 180 /* on ingress, the mac header gets popped, so push it back */ 181 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) 182 skb_push(skb, skb->mac_len); 183 184 md.trunc_size = s->truncate ? s->trunc_size : skb->len; 185 psample_sample_packet(psample_group, skb, s->rate, &md); 186 187 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) 188 skb_pull(skb, skb->mac_len); 189 } 190 191 return retval; 192 } 193 194 static void tcf_sample_stats_update(struct tc_action *a, u64 bytes, u64 packets, 195 u64 drops, u64 lastuse, bool hw) 196 { 197 struct tcf_sample *s = to_sample(a); 198 struct tcf_t *tm = &s->tcf_tm; 199 200 tcf_action_update_stats(a, bytes, packets, drops, hw); 201 tm->lastuse = max_t(u64, tm->lastuse, lastuse); 202 } 203 204 static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a, 205 int bind, int ref) 206 { 207 unsigned char *b = skb_tail_pointer(skb); 208 struct tcf_sample *s = to_sample(a); 209 struct tc_sample opt = { 210 .index = s->tcf_index, 211 .refcnt = refcount_read(&s->tcf_refcnt) - ref, 212 .bindcnt = atomic_read(&s->tcf_bindcnt) - bind, 213 }; 214 struct tcf_t t; 215 216 spin_lock_bh(&s->tcf_lock); 217 opt.action = s->tcf_action; 218 if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt)) 219 goto nla_put_failure; 220 221 tcf_tm_dump(&t, &s->tcf_tm); 222 if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD)) 223 goto nla_put_failure; 224 225 if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate)) 226 goto nla_put_failure; 227 228 if (s->truncate) 229 if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size)) 230 goto nla_put_failure; 231 232 if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num)) 233 goto nla_put_failure; 234 spin_unlock_bh(&s->tcf_lock); 235 236 return skb->len; 237 238 nla_put_failure: 239 spin_unlock_bh(&s->tcf_lock); 240 nlmsg_trim(skb, b); 241 return -1; 242 } 243 244 static int tcf_sample_walker(struct net *net, struct sk_buff *skb, 245 struct netlink_callback *cb, int type, 246 const struct tc_action_ops *ops, 247 struct netlink_ext_ack *extack) 248 { 249 struct tc_action_net *tn = net_generic(net, sample_net_id); 250 251 return tcf_generic_walker(tn, skb, cb, type, ops, extack); 252 } 253 254 static int tcf_sample_search(struct net *net, struct tc_action **a, u32 index) 255 { 256 struct tc_action_net *tn = net_generic(net, sample_net_id); 257 258 return tcf_idr_search(tn, a, index); 259 } 260 261 static void tcf_psample_group_put(void *priv) 262 { 263 struct psample_group *group = priv; 264 265 psample_group_put(group); 266 } 267 268 static struct psample_group * 269 tcf_sample_get_group(const struct tc_action *a, 270 tc_action_priv_destructor *destructor) 271 { 272 struct tcf_sample *s = to_sample(a); 273 struct psample_group *group; 274 275 group = rcu_dereference_protected(s->psample_group, 276 lockdep_is_held(&s->tcf_lock)); 277 if (group) { 278 psample_group_take(group); 279 *destructor = tcf_psample_group_put; 280 } 281 282 return group; 283 } 284 285 static struct tc_action_ops act_sample_ops = { 286 .kind = "sample", 287 .id = TCA_ID_SAMPLE, 288 .owner = THIS_MODULE, 289 .act = tcf_sample_act, 290 .stats_update = tcf_sample_stats_update, 291 .dump = tcf_sample_dump, 292 .init = tcf_sample_init, 293 .cleanup = tcf_sample_cleanup, 294 .walk = tcf_sample_walker, 295 .lookup = tcf_sample_search, 296 .get_psample_group = tcf_sample_get_group, 297 .size = sizeof(struct tcf_sample), 298 }; 299 300 static __net_init int sample_init_net(struct net *net) 301 { 302 struct tc_action_net *tn = net_generic(net, sample_net_id); 303 304 return tc_action_net_init(net, tn, &act_sample_ops); 305 } 306 307 static void __net_exit sample_exit_net(struct list_head *net_list) 308 { 309 tc_action_net_exit(net_list, sample_net_id); 310 } 311 312 static struct pernet_operations sample_net_ops = { 313 .init = sample_init_net, 314 .exit_batch = sample_exit_net, 315 .id = &sample_net_id, 316 .size = sizeof(struct tc_action_net), 317 }; 318 319 static int __init sample_init_module(void) 320 { 321 return tcf_register_action(&act_sample_ops, &sample_net_ops); 322 } 323 324 static void __exit sample_cleanup_module(void) 325 { 326 tcf_unregister_action(&act_sample_ops, &sample_net_ops); 327 } 328 329 module_init(sample_init_module); 330 module_exit(sample_cleanup_module); 331 332 MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>"); 333 MODULE_DESCRIPTION("Packet sampling action"); 334 MODULE_LICENSE("GPL v2"); 335