1 /* 2 * net/sched/act_sample.c - Packet sampling tc action 3 * Copyright (c) 2017 Yotam Gigi <yotamg@mellanox.com> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 as 7 * published by the Free Software Foundation. 8 */ 9 10 #include <linux/types.h> 11 #include <linux/kernel.h> 12 #include <linux/string.h> 13 #include <linux/errno.h> 14 #include <linux/skbuff.h> 15 #include <linux/rtnetlink.h> 16 #include <linux/module.h> 17 #include <linux/init.h> 18 #include <linux/gfp.h> 19 #include <net/net_namespace.h> 20 #include <net/netlink.h> 21 #include <net/pkt_sched.h> 22 #include <linux/tc_act/tc_sample.h> 23 #include <net/tc_act/tc_sample.h> 24 #include <net/psample.h> 25 #include <net/pkt_cls.h> 26 27 #include <linux/if_arp.h> 28 29 static unsigned int sample_net_id; 30 static struct tc_action_ops act_sample_ops; 31 32 static const struct nla_policy sample_policy[TCA_SAMPLE_MAX + 1] = { 33 [TCA_SAMPLE_PARMS] = { .len = sizeof(struct tc_sample) }, 34 [TCA_SAMPLE_RATE] = { .type = NLA_U32 }, 35 [TCA_SAMPLE_TRUNC_SIZE] = { .type = NLA_U32 }, 36 [TCA_SAMPLE_PSAMPLE_GROUP] = { .type = NLA_U32 }, 37 }; 38 39 static int tcf_sample_init(struct net *net, struct nlattr *nla, 40 struct nlattr *est, struct tc_action **a, int ovr, 41 int bind, bool rtnl_held, struct tcf_proto *tp, 42 struct netlink_ext_ack *extack) 43 { 44 struct tc_action_net *tn = net_generic(net, sample_net_id); 45 struct nlattr *tb[TCA_SAMPLE_MAX + 1]; 46 struct psample_group *psample_group; 47 struct tcf_chain *goto_ch = NULL; 48 u32 psample_group_num, rate; 49 struct tc_sample *parm; 50 struct tcf_sample *s; 51 bool exists = false; 52 int ret, err; 53 54 if (!nla) 55 return -EINVAL; 56 ret = nla_parse_nested_deprecated(tb, TCA_SAMPLE_MAX, nla, 57 sample_policy, NULL); 58 if (ret < 0) 59 return ret; 60 if (!tb[TCA_SAMPLE_PARMS] || !tb[TCA_SAMPLE_RATE] || 61 !tb[TCA_SAMPLE_PSAMPLE_GROUP]) 62 return -EINVAL; 63 64 parm = nla_data(tb[TCA_SAMPLE_PARMS]); 65 66 err = tcf_idr_check_alloc(tn, &parm->index, a, bind); 67 if (err < 0) 68 return err; 69 exists = err; 70 if (exists && bind) 71 return 0; 72 73 if (!exists) { 74 ret = tcf_idr_create(tn, parm->index, est, a, 75 &act_sample_ops, bind, true); 76 if (ret) { 77 tcf_idr_cleanup(tn, parm->index); 78 return ret; 79 } 80 ret = ACT_P_CREATED; 81 } else if (!ovr) { 82 tcf_idr_release(*a, bind); 83 return -EEXIST; 84 } 85 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack); 86 if (err < 0) 87 goto release_idr; 88 89 rate = nla_get_u32(tb[TCA_SAMPLE_RATE]); 90 if (!rate) { 91 NL_SET_ERR_MSG(extack, "invalid sample rate"); 92 err = -EINVAL; 93 goto put_chain; 94 } 95 psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]); 96 psample_group = psample_group_get(net, psample_group_num); 97 if (!psample_group) { 98 err = -ENOMEM; 99 goto put_chain; 100 } 101 102 s = to_sample(*a); 103 104 spin_lock_bh(&s->tcf_lock); 105 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch); 106 s->rate = rate; 107 s->psample_group_num = psample_group_num; 108 RCU_INIT_POINTER(s->psample_group, psample_group); 109 110 if (tb[TCA_SAMPLE_TRUNC_SIZE]) { 111 s->truncate = true; 112 s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]); 113 } 114 spin_unlock_bh(&s->tcf_lock); 115 if (goto_ch) 116 tcf_chain_put_by_act(goto_ch); 117 118 if (ret == ACT_P_CREATED) 119 tcf_idr_insert(tn, *a); 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_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 struct tc_action_ops act_sample_ops = { 255 .kind = "sample", 256 .id = TCA_ID_SAMPLE, 257 .owner = THIS_MODULE, 258 .act = tcf_sample_act, 259 .dump = tcf_sample_dump, 260 .init = tcf_sample_init, 261 .cleanup = tcf_sample_cleanup, 262 .walk = tcf_sample_walker, 263 .lookup = tcf_sample_search, 264 .size = sizeof(struct tcf_sample), 265 }; 266 267 static __net_init int sample_init_net(struct net *net) 268 { 269 struct tc_action_net *tn = net_generic(net, sample_net_id); 270 271 return tc_action_net_init(tn, &act_sample_ops); 272 } 273 274 static void __net_exit sample_exit_net(struct list_head *net_list) 275 { 276 tc_action_net_exit(net_list, sample_net_id); 277 } 278 279 static struct pernet_operations sample_net_ops = { 280 .init = sample_init_net, 281 .exit_batch = sample_exit_net, 282 .id = &sample_net_id, 283 .size = sizeof(struct tc_action_net), 284 }; 285 286 static int __init sample_init_module(void) 287 { 288 return tcf_register_action(&act_sample_ops, &sample_net_ops); 289 } 290 291 static void __exit sample_cleanup_module(void) 292 { 293 tcf_unregister_action(&act_sample_ops, &sample_net_ops); 294 } 295 296 module_init(sample_init_module); 297 module_exit(sample_cleanup_module); 298 299 MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>"); 300 MODULE_DESCRIPTION("Packet sampling action"); 301 MODULE_LICENSE("GPL v2"); 302