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 26 #include <linux/if_arp.h> 27 28 #define SAMPLE_TAB_MASK 7 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) 42 { 43 struct tc_action_net *tn = net_generic(net, sample_net_id); 44 struct nlattr *tb[TCA_SAMPLE_MAX + 1]; 45 struct psample_group *psample_group; 46 struct tc_sample *parm; 47 struct tcf_sample *s; 48 bool exists = false; 49 int ret; 50 51 if (!nla) 52 return -EINVAL; 53 ret = nla_parse_nested(tb, TCA_SAMPLE_MAX, nla, sample_policy, NULL); 54 if (ret < 0) 55 return ret; 56 if (!tb[TCA_SAMPLE_PARMS] || !tb[TCA_SAMPLE_RATE] || 57 !tb[TCA_SAMPLE_PSAMPLE_GROUP]) 58 return -EINVAL; 59 60 parm = nla_data(tb[TCA_SAMPLE_PARMS]); 61 62 exists = tcf_hash_check(tn, parm->index, a, bind); 63 if (exists && bind) 64 return 0; 65 66 if (!exists) { 67 ret = tcf_hash_create(tn, parm->index, est, a, 68 &act_sample_ops, bind, false); 69 if (ret) 70 return ret; 71 ret = ACT_P_CREATED; 72 } else { 73 tcf_hash_release(*a, bind); 74 if (!ovr) 75 return -EEXIST; 76 } 77 s = to_sample(*a); 78 79 s->tcf_action = parm->action; 80 s->rate = nla_get_u32(tb[TCA_SAMPLE_RATE]); 81 s->psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]); 82 psample_group = psample_group_get(net, s->psample_group_num); 83 if (!psample_group) { 84 if (ret == ACT_P_CREATED) 85 tcf_hash_release(*a, bind); 86 return -ENOMEM; 87 } 88 RCU_INIT_POINTER(s->psample_group, psample_group); 89 90 if (tb[TCA_SAMPLE_TRUNC_SIZE]) { 91 s->truncate = true; 92 s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]); 93 } 94 95 if (ret == ACT_P_CREATED) 96 tcf_hash_insert(tn, *a); 97 return ret; 98 } 99 100 static void tcf_sample_cleanup_rcu(struct rcu_head *rcu) 101 { 102 struct tcf_sample *s = container_of(rcu, struct tcf_sample, rcu); 103 struct psample_group *psample_group; 104 105 psample_group = rcu_dereference_protected(s->psample_group, 1); 106 RCU_INIT_POINTER(s->psample_group, NULL); 107 psample_group_put(psample_group); 108 } 109 110 static void tcf_sample_cleanup(struct tc_action *a, int bind) 111 { 112 struct tcf_sample *s = to_sample(a); 113 114 call_rcu(&s->rcu, tcf_sample_cleanup_rcu); 115 } 116 117 static bool tcf_sample_dev_ok_push(struct net_device *dev) 118 { 119 switch (dev->type) { 120 case ARPHRD_TUNNEL: 121 case ARPHRD_TUNNEL6: 122 case ARPHRD_SIT: 123 case ARPHRD_IPGRE: 124 case ARPHRD_VOID: 125 case ARPHRD_NONE: 126 return false; 127 default: 128 return true; 129 } 130 } 131 132 static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a, 133 struct tcf_result *res) 134 { 135 struct tcf_sample *s = to_sample(a); 136 struct psample_group *psample_group; 137 int retval; 138 int size; 139 int iif; 140 int oif; 141 142 tcf_lastuse_update(&s->tcf_tm); 143 bstats_cpu_update(this_cpu_ptr(s->common.cpu_bstats), skb); 144 retval = READ_ONCE(s->tcf_action); 145 146 rcu_read_lock(); 147 psample_group = rcu_dereference(s->psample_group); 148 149 /* randomly sample packets according to rate */ 150 if (psample_group && (prandom_u32() % s->rate == 0)) { 151 if (!skb_at_tc_ingress(skb)) { 152 iif = skb->skb_iif; 153 oif = skb->dev->ifindex; 154 } else { 155 iif = skb->dev->ifindex; 156 oif = 0; 157 } 158 159 /* on ingress, the mac header gets popped, so push it back */ 160 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) 161 skb_push(skb, skb->mac_len); 162 163 size = s->truncate ? s->trunc_size : skb->len; 164 psample_sample_packet(psample_group, skb, size, iif, oif, 165 s->rate); 166 167 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) 168 skb_pull(skb, skb->mac_len); 169 } 170 171 rcu_read_unlock(); 172 return retval; 173 } 174 175 static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a, 176 int bind, int ref) 177 { 178 unsigned char *b = skb_tail_pointer(skb); 179 struct tcf_sample *s = to_sample(a); 180 struct tc_sample opt = { 181 .index = s->tcf_index, 182 .action = s->tcf_action, 183 .refcnt = s->tcf_refcnt - ref, 184 .bindcnt = s->tcf_bindcnt - bind, 185 }; 186 struct tcf_t t; 187 188 if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt)) 189 goto nla_put_failure; 190 191 tcf_tm_dump(&t, &s->tcf_tm); 192 if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD)) 193 goto nla_put_failure; 194 195 if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate)) 196 goto nla_put_failure; 197 198 if (s->truncate) 199 if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size)) 200 goto nla_put_failure; 201 202 if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num)) 203 goto nla_put_failure; 204 return skb->len; 205 206 nla_put_failure: 207 nlmsg_trim(skb, b); 208 return -1; 209 } 210 211 static int tcf_sample_walker(struct net *net, struct sk_buff *skb, 212 struct netlink_callback *cb, int type, 213 const struct tc_action_ops *ops) 214 { 215 struct tc_action_net *tn = net_generic(net, sample_net_id); 216 217 return tcf_generic_walker(tn, skb, cb, type, ops); 218 } 219 220 static int tcf_sample_search(struct net *net, struct tc_action **a, u32 index) 221 { 222 struct tc_action_net *tn = net_generic(net, sample_net_id); 223 224 return tcf_hash_search(tn, a, index); 225 } 226 227 static struct tc_action_ops act_sample_ops = { 228 .kind = "sample", 229 .type = TCA_ACT_SAMPLE, 230 .owner = THIS_MODULE, 231 .act = tcf_sample_act, 232 .dump = tcf_sample_dump, 233 .init = tcf_sample_init, 234 .cleanup = tcf_sample_cleanup, 235 .walk = tcf_sample_walker, 236 .lookup = tcf_sample_search, 237 .size = sizeof(struct tcf_sample), 238 }; 239 240 static __net_init int sample_init_net(struct net *net) 241 { 242 struct tc_action_net *tn = net_generic(net, sample_net_id); 243 244 return tc_action_net_init(tn, &act_sample_ops, SAMPLE_TAB_MASK); 245 } 246 247 static void __net_exit sample_exit_net(struct net *net) 248 { 249 struct tc_action_net *tn = net_generic(net, sample_net_id); 250 251 tc_action_net_exit(tn); 252 } 253 254 static struct pernet_operations sample_net_ops = { 255 .init = sample_init_net, 256 .exit = sample_exit_net, 257 .id = &sample_net_id, 258 .size = sizeof(struct tc_action_net), 259 }; 260 261 static int __init sample_init_module(void) 262 { 263 return tcf_register_action(&act_sample_ops, &sample_net_ops); 264 } 265 266 static void __exit sample_cleanup_module(void) 267 { 268 tcf_unregister_action(&act_sample_ops, &sample_net_ops); 269 } 270 271 module_init(sample_init_module); 272 module_exit(sample_cleanup_module); 273 274 MODULE_AUTHOR("Yotam Gigi <yotamg@mellanox.com>"); 275 MODULE_DESCRIPTION("Packet sampling action"); 276 MODULE_LICENSE("GPL v2"); 277