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 struct tc_sample *parm; 49 u32 psample_group_num; 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(tb, TCA_SAMPLE_MAX, nla, sample_policy, NULL); 57 if (ret < 0) 58 return ret; 59 if (!tb[TCA_SAMPLE_PARMS] || !tb[TCA_SAMPLE_RATE] || 60 !tb[TCA_SAMPLE_PSAMPLE_GROUP]) 61 return -EINVAL; 62 63 parm = nla_data(tb[TCA_SAMPLE_PARMS]); 64 65 err = tcf_idr_check_alloc(tn, &parm->index, a, bind); 66 if (err < 0) 67 return err; 68 exists = err; 69 if (exists && bind) 70 return 0; 71 72 if (!exists) { 73 ret = tcf_idr_create(tn, parm->index, est, a, 74 &act_sample_ops, bind, true); 75 if (ret) { 76 tcf_idr_cleanup(tn, parm->index); 77 return ret; 78 } 79 ret = ACT_P_CREATED; 80 } else if (!ovr) { 81 tcf_idr_release(*a, bind); 82 return -EEXIST; 83 } 84 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack); 85 if (err < 0) 86 goto release_idr; 87 88 psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]); 89 psample_group = psample_group_get(net, psample_group_num); 90 if (!psample_group) { 91 err = -ENOMEM; 92 goto put_chain; 93 } 94 95 s = to_sample(*a); 96 97 spin_lock_bh(&s->tcf_lock); 98 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch); 99 s->rate = nla_get_u32(tb[TCA_SAMPLE_RATE]); 100 s->psample_group_num = psample_group_num; 101 RCU_INIT_POINTER(s->psample_group, psample_group); 102 103 if (tb[TCA_SAMPLE_TRUNC_SIZE]) { 104 s->truncate = true; 105 s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]); 106 } 107 spin_unlock_bh(&s->tcf_lock); 108 if (goto_ch) 109 tcf_chain_put_by_act(goto_ch); 110 111 if (ret == ACT_P_CREATED) 112 tcf_idr_insert(tn, *a); 113 return ret; 114 put_chain: 115 if (goto_ch) 116 tcf_chain_put_by_act(goto_ch); 117 release_idr: 118 tcf_idr_release(*a, bind); 119 return err; 120 } 121 122 static void tcf_sample_cleanup(struct tc_action *a) 123 { 124 struct tcf_sample *s = to_sample(a); 125 struct psample_group *psample_group; 126 127 /* last reference to action, no need to lock */ 128 psample_group = rcu_dereference_protected(s->psample_group, 1); 129 RCU_INIT_POINTER(s->psample_group, NULL); 130 if (psample_group) 131 psample_group_put(psample_group); 132 } 133 134 static bool tcf_sample_dev_ok_push(struct net_device *dev) 135 { 136 switch (dev->type) { 137 case ARPHRD_TUNNEL: 138 case ARPHRD_TUNNEL6: 139 case ARPHRD_SIT: 140 case ARPHRD_IPGRE: 141 case ARPHRD_VOID: 142 case ARPHRD_NONE: 143 return false; 144 default: 145 return true; 146 } 147 } 148 149 static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a, 150 struct tcf_result *res) 151 { 152 struct tcf_sample *s = to_sample(a); 153 struct psample_group *psample_group; 154 int retval; 155 int size; 156 int iif; 157 int oif; 158 159 tcf_lastuse_update(&s->tcf_tm); 160 bstats_cpu_update(this_cpu_ptr(s->common.cpu_bstats), skb); 161 retval = READ_ONCE(s->tcf_action); 162 163 psample_group = rcu_dereference_bh(s->psample_group); 164 165 /* randomly sample packets according to rate */ 166 if (psample_group && (prandom_u32() % s->rate == 0)) { 167 if (!skb_at_tc_ingress(skb)) { 168 iif = skb->skb_iif; 169 oif = skb->dev->ifindex; 170 } else { 171 iif = skb->dev->ifindex; 172 oif = 0; 173 } 174 175 /* on ingress, the mac header gets popped, so push it back */ 176 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) 177 skb_push(skb, skb->mac_len); 178 179 size = s->truncate ? s->trunc_size : skb->len; 180 psample_sample_packet(psample_group, skb, size, iif, oif, 181 s->rate); 182 183 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) 184 skb_pull(skb, skb->mac_len); 185 } 186 187 return retval; 188 } 189 190 static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a, 191 int bind, int ref) 192 { 193 unsigned char *b = skb_tail_pointer(skb); 194 struct tcf_sample *s = to_sample(a); 195 struct tc_sample opt = { 196 .index = s->tcf_index, 197 .refcnt = refcount_read(&s->tcf_refcnt) - ref, 198 .bindcnt = atomic_read(&s->tcf_bindcnt) - bind, 199 }; 200 struct tcf_t t; 201 202 spin_lock_bh(&s->tcf_lock); 203 opt.action = s->tcf_action; 204 if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt)) 205 goto nla_put_failure; 206 207 tcf_tm_dump(&t, &s->tcf_tm); 208 if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD)) 209 goto nla_put_failure; 210 211 if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate)) 212 goto nla_put_failure; 213 214 if (s->truncate) 215 if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size)) 216 goto nla_put_failure; 217 218 if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num)) 219 goto nla_put_failure; 220 spin_unlock_bh(&s->tcf_lock); 221 222 return skb->len; 223 224 nla_put_failure: 225 spin_unlock_bh(&s->tcf_lock); 226 nlmsg_trim(skb, b); 227 return -1; 228 } 229 230 static int tcf_sample_walker(struct net *net, struct sk_buff *skb, 231 struct netlink_callback *cb, int type, 232 const struct tc_action_ops *ops, 233 struct netlink_ext_ack *extack) 234 { 235 struct tc_action_net *tn = net_generic(net, sample_net_id); 236 237 return tcf_generic_walker(tn, skb, cb, type, ops, extack); 238 } 239 240 static int tcf_sample_search(struct net *net, struct tc_action **a, u32 index) 241 { 242 struct tc_action_net *tn = net_generic(net, sample_net_id); 243 244 return tcf_idr_search(tn, a, index); 245 } 246 247 static struct tc_action_ops act_sample_ops = { 248 .kind = "sample", 249 .id = TCA_ID_SAMPLE, 250 .owner = THIS_MODULE, 251 .act = tcf_sample_act, 252 .dump = tcf_sample_dump, 253 .init = tcf_sample_init, 254 .cleanup = tcf_sample_cleanup, 255 .walk = tcf_sample_walker, 256 .lookup = tcf_sample_search, 257 .size = sizeof(struct tcf_sample), 258 }; 259 260 static __net_init int sample_init_net(struct net *net) 261 { 262 struct tc_action_net *tn = net_generic(net, sample_net_id); 263 264 return tc_action_net_init(tn, &act_sample_ops); 265 } 266 267 static void __net_exit sample_exit_net(struct list_head *net_list) 268 { 269 tc_action_net_exit(net_list, sample_net_id); 270 } 271 272 static struct pernet_operations sample_net_ops = { 273 .init = sample_init_net, 274 .exit_batch = sample_exit_net, 275 .id = &sample_net_id, 276 .size = sizeof(struct tc_action_net), 277 }; 278 279 static int __init sample_init_module(void) 280 { 281 return tcf_register_action(&act_sample_ops, &sample_net_ops); 282 } 283 284 static void __exit sample_cleanup_module(void) 285 { 286 tcf_unregister_action(&act_sample_ops, &sample_net_ops); 287 } 288 289 module_init(sample_init_module); 290 module_exit(sample_cleanup_module); 291 292 MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>"); 293 MODULE_DESCRIPTION("Packet sampling action"); 294 MODULE_LICENSE("GPL v2"); 295