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, int ovr, 38 int bind, bool rtnl_held, 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 struct nlattr *tb[TCA_SAMPLE_MAX + 1]; 43 struct psample_group *psample_group; 44 u32 psample_group_num, rate, index; 45 struct tcf_chain *goto_ch = NULL; 46 struct tc_sample *parm; 47 struct tcf_sample *s; 48 bool exists = false; 49 int ret, err; 50 51 if (!nla) 52 return -EINVAL; 53 ret = nla_parse_nested_deprecated(tb, TCA_SAMPLE_MAX, nla, 54 sample_policy, NULL); 55 if (ret < 0) 56 return ret; 57 if (!tb[TCA_SAMPLE_PARMS] || !tb[TCA_SAMPLE_RATE] || 58 !tb[TCA_SAMPLE_PSAMPLE_GROUP]) 59 return -EINVAL; 60 61 parm = nla_data(tb[TCA_SAMPLE_PARMS]); 62 index = parm->index; 63 err = tcf_idr_check_alloc(tn, &index, a, bind); 64 if (err < 0) 65 return err; 66 exists = err; 67 if (exists && bind) 68 return 0; 69 70 if (!exists) { 71 ret = tcf_idr_create(tn, index, est, a, 72 &act_sample_ops, bind, true, 0); 73 if (ret) { 74 tcf_idr_cleanup(tn, index); 75 return ret; 76 } 77 ret = ACT_P_CREATED; 78 } else if (!ovr) { 79 tcf_idr_release(*a, bind); 80 return -EEXIST; 81 } 82 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack); 83 if (err < 0) 84 goto release_idr; 85 86 rate = nla_get_u32(tb[TCA_SAMPLE_RATE]); 87 if (!rate) { 88 NL_SET_ERR_MSG(extack, "invalid sample rate"); 89 err = -EINVAL; 90 goto put_chain; 91 } 92 psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]); 93 psample_group = psample_group_get(net, psample_group_num); 94 if (!psample_group) { 95 err = -ENOMEM; 96 goto put_chain; 97 } 98 99 s = to_sample(*a); 100 101 spin_lock_bh(&s->tcf_lock); 102 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch); 103 s->rate = rate; 104 s->psample_group_num = psample_group_num; 105 psample_group = rcu_replace_pointer(s->psample_group, psample_group, 106 lockdep_is_held(&s->tcf_lock)); 107 108 if (tb[TCA_SAMPLE_TRUNC_SIZE]) { 109 s->truncate = true; 110 s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]); 111 } 112 spin_unlock_bh(&s->tcf_lock); 113 114 if (psample_group) 115 psample_group_put(psample_group); 116 if (goto_ch) 117 tcf_chain_put_by_act(goto_ch); 118 119 return ret; 120 put_chain: 121 if (goto_ch) 122 tcf_chain_put_by_act(goto_ch); 123 release_idr: 124 tcf_idr_release(*a, bind); 125 return err; 126 } 127 128 static void tcf_sample_cleanup(struct tc_action *a) 129 { 130 struct tcf_sample *s = to_sample(a); 131 struct psample_group *psample_group; 132 133 /* last reference to action, no need to lock */ 134 psample_group = rcu_dereference_protected(s->psample_group, 1); 135 RCU_INIT_POINTER(s->psample_group, NULL); 136 if (psample_group) 137 psample_group_put(psample_group); 138 } 139 140 static bool tcf_sample_dev_ok_push(struct net_device *dev) 141 { 142 switch (dev->type) { 143 case ARPHRD_TUNNEL: 144 case ARPHRD_TUNNEL6: 145 case ARPHRD_SIT: 146 case ARPHRD_IPGRE: 147 case ARPHRD_IP6GRE: 148 case ARPHRD_VOID: 149 case ARPHRD_NONE: 150 return false; 151 default: 152 return true; 153 } 154 } 155 156 static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a, 157 struct tcf_result *res) 158 { 159 struct tcf_sample *s = to_sample(a); 160 struct psample_group *psample_group; 161 int retval; 162 int size; 163 int iif; 164 int oif; 165 166 tcf_lastuse_update(&s->tcf_tm); 167 bstats_cpu_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 && (prandom_u32() % s->rate == 0)) { 174 if (!skb_at_tc_ingress(skb)) { 175 iif = skb->skb_iif; 176 oif = skb->dev->ifindex; 177 } else { 178 iif = skb->dev->ifindex; 179 oif = 0; 180 } 181 182 /* on ingress, the mac header gets popped, so push it back */ 183 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) 184 skb_push(skb, skb->mac_len); 185 186 size = s->truncate ? s->trunc_size : skb->len; 187 psample_sample_packet(psample_group, skb, size, iif, oif, 188 s->rate); 189 190 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) 191 skb_pull(skb, skb->mac_len); 192 } 193 194 return retval; 195 } 196 197 static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a, 198 int bind, int ref) 199 { 200 unsigned char *b = skb_tail_pointer(skb); 201 struct tcf_sample *s = to_sample(a); 202 struct tc_sample opt = { 203 .index = s->tcf_index, 204 .refcnt = refcount_read(&s->tcf_refcnt) - ref, 205 .bindcnt = atomic_read(&s->tcf_bindcnt) - bind, 206 }; 207 struct tcf_t t; 208 209 spin_lock_bh(&s->tcf_lock); 210 opt.action = s->tcf_action; 211 if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt)) 212 goto nla_put_failure; 213 214 tcf_tm_dump(&t, &s->tcf_tm); 215 if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD)) 216 goto nla_put_failure; 217 218 if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate)) 219 goto nla_put_failure; 220 221 if (s->truncate) 222 if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size)) 223 goto nla_put_failure; 224 225 if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num)) 226 goto nla_put_failure; 227 spin_unlock_bh(&s->tcf_lock); 228 229 return skb->len; 230 231 nla_put_failure: 232 spin_unlock_bh(&s->tcf_lock); 233 nlmsg_trim(skb, b); 234 return -1; 235 } 236 237 static int tcf_sample_walker(struct net *net, struct sk_buff *skb, 238 struct netlink_callback *cb, int type, 239 const struct tc_action_ops *ops, 240 struct netlink_ext_ack *extack) 241 { 242 struct tc_action_net *tn = net_generic(net, sample_net_id); 243 244 return tcf_generic_walker(tn, skb, cb, type, ops, extack); 245 } 246 247 static int tcf_sample_search(struct net *net, struct tc_action **a, u32 index) 248 { 249 struct tc_action_net *tn = net_generic(net, sample_net_id); 250 251 return tcf_idr_search(tn, a, index); 252 } 253 254 static void tcf_psample_group_put(void *priv) 255 { 256 struct psample_group *group = priv; 257 258 psample_group_put(group); 259 } 260 261 static struct psample_group * 262 tcf_sample_get_group(const struct tc_action *a, 263 tc_action_priv_destructor *destructor) 264 { 265 struct tcf_sample *s = to_sample(a); 266 struct psample_group *group; 267 268 group = rcu_dereference_protected(s->psample_group, 269 lockdep_is_held(&s->tcf_lock)); 270 if (group) { 271 psample_group_take(group); 272 *destructor = tcf_psample_group_put; 273 } 274 275 return group; 276 } 277 278 static struct tc_action_ops act_sample_ops = { 279 .kind = "sample", 280 .id = TCA_ID_SAMPLE, 281 .owner = THIS_MODULE, 282 .act = tcf_sample_act, 283 .dump = tcf_sample_dump, 284 .init = tcf_sample_init, 285 .cleanup = tcf_sample_cleanup, 286 .walk = tcf_sample_walker, 287 .lookup = tcf_sample_search, 288 .get_psample_group = tcf_sample_get_group, 289 .size = sizeof(struct tcf_sample), 290 }; 291 292 static __net_init int sample_init_net(struct net *net) 293 { 294 struct tc_action_net *tn = net_generic(net, sample_net_id); 295 296 return tc_action_net_init(net, tn, &act_sample_ops); 297 } 298 299 static void __net_exit sample_exit_net(struct list_head *net_list) 300 { 301 tc_action_net_exit(net_list, sample_net_id); 302 } 303 304 static struct pernet_operations sample_net_ops = { 305 .init = sample_init_net, 306 .exit_batch = sample_exit_net, 307 .id = &sample_net_id, 308 .size = sizeof(struct tc_action_net), 309 }; 310 311 static int __init sample_init_module(void) 312 { 313 return tcf_register_action(&act_sample_ops, &sample_net_ops); 314 } 315 316 static void __exit sample_cleanup_module(void) 317 { 318 tcf_unregister_action(&act_sample_ops, &sample_net_ops); 319 } 320 321 module_init(sample_init_module); 322 module_exit(sample_cleanup_module); 323 324 MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>"); 325 MODULE_DESCRIPTION("Packet sampling action"); 326 MODULE_LICENSE("GPL v2"); 327