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 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 struct tcf_chain *goto_ch = NULL; 45 u32 psample_group_num, rate; 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 63 err = tcf_idr_check_alloc(tn, &parm->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, parm->index, est, a, 72 &act_sample_ops, bind, true); 73 if (ret) { 74 tcf_idr_cleanup(tn, parm->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 RCU_INIT_POINTER(s->psample_group, psample_group); 106 107 if (tb[TCA_SAMPLE_TRUNC_SIZE]) { 108 s->truncate = true; 109 s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]); 110 } 111 spin_unlock_bh(&s->tcf_lock); 112 if (goto_ch) 113 tcf_chain_put_by_act(goto_ch); 114 115 if (ret == ACT_P_CREATED) 116 tcf_idr_insert(tn, *a); 117 return ret; 118 put_chain: 119 if (goto_ch) 120 tcf_chain_put_by_act(goto_ch); 121 release_idr: 122 tcf_idr_release(*a, bind); 123 return err; 124 } 125 126 static void tcf_sample_cleanup(struct tc_action *a) 127 { 128 struct tcf_sample *s = to_sample(a); 129 struct psample_group *psample_group; 130 131 /* last reference to action, no need to lock */ 132 psample_group = rcu_dereference_protected(s->psample_group, 1); 133 RCU_INIT_POINTER(s->psample_group, NULL); 134 if (psample_group) 135 psample_group_put(psample_group); 136 } 137 138 static bool tcf_sample_dev_ok_push(struct net_device *dev) 139 { 140 switch (dev->type) { 141 case ARPHRD_TUNNEL: 142 case ARPHRD_TUNNEL6: 143 case ARPHRD_SIT: 144 case ARPHRD_IPGRE: 145 case ARPHRD_VOID: 146 case ARPHRD_NONE: 147 return false; 148 default: 149 return true; 150 } 151 } 152 153 static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a, 154 struct tcf_result *res) 155 { 156 struct tcf_sample *s = to_sample(a); 157 struct psample_group *psample_group; 158 int retval; 159 int size; 160 int iif; 161 int oif; 162 163 tcf_lastuse_update(&s->tcf_tm); 164 bstats_cpu_update(this_cpu_ptr(s->common.cpu_bstats), skb); 165 retval = READ_ONCE(s->tcf_action); 166 167 psample_group = rcu_dereference_bh(s->psample_group); 168 169 /* randomly sample packets according to rate */ 170 if (psample_group && (prandom_u32() % s->rate == 0)) { 171 if (!skb_at_tc_ingress(skb)) { 172 iif = skb->skb_iif; 173 oif = skb->dev->ifindex; 174 } else { 175 iif = skb->dev->ifindex; 176 oif = 0; 177 } 178 179 /* on ingress, the mac header gets popped, so push it back */ 180 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) 181 skb_push(skb, skb->mac_len); 182 183 size = s->truncate ? s->trunc_size : skb->len; 184 psample_sample_packet(psample_group, skb, size, iif, oif, 185 s->rate); 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 int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a, 195 int bind, int ref) 196 { 197 unsigned char *b = skb_tail_pointer(skb); 198 struct tcf_sample *s = to_sample(a); 199 struct tc_sample opt = { 200 .index = s->tcf_index, 201 .refcnt = refcount_read(&s->tcf_refcnt) - ref, 202 .bindcnt = atomic_read(&s->tcf_bindcnt) - bind, 203 }; 204 struct tcf_t t; 205 206 spin_lock_bh(&s->tcf_lock); 207 opt.action = s->tcf_action; 208 if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt)) 209 goto nla_put_failure; 210 211 tcf_tm_dump(&t, &s->tcf_tm); 212 if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD)) 213 goto nla_put_failure; 214 215 if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate)) 216 goto nla_put_failure; 217 218 if (s->truncate) 219 if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size)) 220 goto nla_put_failure; 221 222 if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num)) 223 goto nla_put_failure; 224 spin_unlock_bh(&s->tcf_lock); 225 226 return skb->len; 227 228 nla_put_failure: 229 spin_unlock_bh(&s->tcf_lock); 230 nlmsg_trim(skb, b); 231 return -1; 232 } 233 234 static int tcf_sample_walker(struct net *net, struct sk_buff *skb, 235 struct netlink_callback *cb, int type, 236 const struct tc_action_ops *ops, 237 struct netlink_ext_ack *extack) 238 { 239 struct tc_action_net *tn = net_generic(net, sample_net_id); 240 241 return tcf_generic_walker(tn, skb, cb, type, ops, extack); 242 } 243 244 static int tcf_sample_search(struct net *net, struct tc_action **a, u32 index) 245 { 246 struct tc_action_net *tn = net_generic(net, sample_net_id); 247 248 return tcf_idr_search(tn, a, index); 249 } 250 251 static struct tc_action_ops act_sample_ops = { 252 .kind = "sample", 253 .id = TCA_ID_SAMPLE, 254 .owner = THIS_MODULE, 255 .act = tcf_sample_act, 256 .dump = tcf_sample_dump, 257 .init = tcf_sample_init, 258 .cleanup = tcf_sample_cleanup, 259 .walk = tcf_sample_walker, 260 .lookup = tcf_sample_search, 261 .size = sizeof(struct tcf_sample), 262 }; 263 264 static __net_init int sample_init_net(struct net *net) 265 { 266 struct tc_action_net *tn = net_generic(net, sample_net_id); 267 268 return tc_action_net_init(tn, &act_sample_ops); 269 } 270 271 static void __net_exit sample_exit_net(struct list_head *net_list) 272 { 273 tc_action_net_exit(net_list, sample_net_id); 274 } 275 276 static struct pernet_operations sample_net_ops = { 277 .init = sample_init_net, 278 .exit_batch = sample_exit_net, 279 .id = &sample_net_id, 280 .size = sizeof(struct tc_action_net), 281 }; 282 283 static int __init sample_init_module(void) 284 { 285 return tcf_register_action(&act_sample_ops, &sample_net_ops); 286 } 287 288 static void __exit sample_cleanup_module(void) 289 { 290 tcf_unregister_action(&act_sample_ops, &sample_net_ops); 291 } 292 293 module_init(sample_init_module); 294 module_exit(sample_cleanup_module); 295 296 MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>"); 297 MODULE_DESCRIPTION("Packet sampling action"); 298 MODULE_LICENSE("GPL v2"); 299