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 26static unsigned int sample_net_id; 27static struct tc_action_ops act_sample_ops; 28 29static 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 36static 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 58 if (!tb[TCA_SAMPLE_PARMS]) 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, flags); 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 83 if (!tb[TCA_SAMPLE_RATE] || !tb[TCA_SAMPLE_PSAMPLE_GROUP]) { 84 NL_SET_ERR_MSG(extack, "sample rate and group are required"); 85 err = -EINVAL; 86 goto release_idr; 87 } 88 89 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack); 90 if (err < 0) 91 goto release_idr; 92 93 rate = nla_get_u32(tb[TCA_SAMPLE_RATE]); 94 if (!rate) { 95 NL_SET_ERR_MSG(extack, "invalid sample rate"); 96 err = -EINVAL; 97 goto put_chain; 98 } 99 psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]); 100 psample_group = psample_group_get(net, psample_group_num); 101 if (!psample_group) { 102 err = -ENOMEM; 103 goto put_chain; 104 } 105 106 s = to_sample(*a); 107 108 spin_lock_bh(&s->tcf_lock); 109 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch); 110 s->rate = rate; 111 s->psample_group_num = psample_group_num; 112 psample_group = rcu_replace_pointer(s->psample_group, psample_group, 113 lockdep_is_held(&s->tcf_lock)); 114 115 if (tb[TCA_SAMPLE_TRUNC_SIZE]) { 116 s->truncate = true; 117 s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]); 118 } 119 spin_unlock_bh(&s->tcf_lock); 120 121 if (psample_group) 122 psample_group_put(psample_group); 123 if (goto_ch) 124 tcf_chain_put_by_act(goto_ch); 125 126 return ret; 127put_chain: 128 if (goto_ch) 129 tcf_chain_put_by_act(goto_ch); 130release_idr: 131 tcf_idr_release(*a, bind); 132 return err; 133} 134 135static void tcf_sample_cleanup(struct tc_action *a) 136{ 137 struct tcf_sample *s = to_sample(a); 138 struct psample_group *psample_group; 139 140 /* last reference to action, no need to lock */ 141 psample_group = rcu_dereference_protected(s->psample_group, 1); 142 RCU_INIT_POINTER(s->psample_group, NULL); 143 if (psample_group) 144 psample_group_put(psample_group); 145} 146 147static bool tcf_sample_dev_ok_push(struct net_device *dev) 148{ 149 switch (dev->type) { 150 case ARPHRD_TUNNEL: 151 case ARPHRD_TUNNEL6: 152 case ARPHRD_SIT: 153 case ARPHRD_IPGRE: 154 case ARPHRD_IP6GRE: 155 case ARPHRD_VOID: 156 case ARPHRD_NONE: 157 return false; 158 default: 159 return true; 160 } 161} 162 163static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a, 164 struct tcf_result *res) 165{ 166 struct tcf_sample *s = to_sample(a); 167 struct psample_group *psample_group; 168 int retval; 169 int size; 170 int iif; 171 int oif; 172 173 tcf_lastuse_update(&s->tcf_tm); 174 bstats_cpu_update(this_cpu_ptr(s->common.cpu_bstats), skb); 175 retval = READ_ONCE(s->tcf_action); 176 177 psample_group = rcu_dereference_bh(s->psample_group); 178 179 /* randomly sample packets according to rate */ 180 if (psample_group && (prandom_u32() % s->rate == 0)) { 181 if (!skb_at_tc_ingress(skb)) { 182 iif = skb->skb_iif; 183 oif = skb->dev->ifindex; 184 } else { 185 iif = skb->dev->ifindex; 186 oif = 0; 187 } 188 189 /* on ingress, the mac header gets popped, so push it back */ 190 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) 191 skb_push(skb, skb->mac_len); 192 193 size = s->truncate ? s->trunc_size : skb->len; 194 psample_sample_packet(psample_group, skb, size, iif, oif, 195 s->rate); 196 197 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) 198 skb_pull(skb, skb->mac_len); 199 } 200 201 return retval; 202} 203 204static 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 238nla_put_failure: 239 spin_unlock_bh(&s->tcf_lock); 240 nlmsg_trim(skb, b); 241 return -1; 242} 243 244static 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 254static 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 261static void tcf_psample_group_put(void *priv) 262{ 263 struct psample_group *group = priv; 264 265 psample_group_put(group); 266} 267 268static struct psample_group * 269tcf_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 285static 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 .dump = tcf_sample_dump, 291 .init = tcf_sample_init, 292 .cleanup = tcf_sample_cleanup, 293 .walk = tcf_sample_walker, 294 .lookup = tcf_sample_search, 295 .get_psample_group = tcf_sample_get_group, 296 .size = sizeof(struct tcf_sample), 297}; 298 299static __net_init int sample_init_net(struct net *net) 300{ 301 struct tc_action_net *tn = net_generic(net, sample_net_id); 302 303 return tc_action_net_init(net, tn, &act_sample_ops); 304} 305 306static void __net_exit sample_exit_net(struct list_head *net_list) 307{ 308 tc_action_net_exit(net_list, sample_net_id); 309} 310 311static struct pernet_operations sample_net_ops = { 312 .init = sample_init_net, 313 .exit_batch = sample_exit_net, 314 .id = &sample_net_id, 315 .size = sizeof(struct tc_action_net), 316}; 317 318static int __init sample_init_module(void) 319{ 320 return tcf_register_action(&act_sample_ops, &sample_net_ops); 321} 322 323static void __exit sample_cleanup_module(void) 324{ 325 tcf_unregister_action(&act_sample_ops, &sample_net_ops); 326} 327 328module_init(sample_init_module); 329module_exit(sample_cleanup_module); 330 331MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>"); 332MODULE_DESCRIPTION("Packet sampling action"); 333MODULE_LICENSE("GPL v2"); 334