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 static unsigned int sample_net_id; 29 static struct tc_action_ops act_sample_ops; 30 31 static const struct nla_policy sample_policy[TCA_SAMPLE_MAX + 1] = { 32 [TCA_SAMPLE_PARMS] = { .len = sizeof(struct tc_sample) }, 33 [TCA_SAMPLE_RATE] = { .type = NLA_U32 }, 34 [TCA_SAMPLE_TRUNC_SIZE] = { .type = NLA_U32 }, 35 [TCA_SAMPLE_PSAMPLE_GROUP] = { .type = NLA_U32 }, 36 }; 37 38 static int tcf_sample_init(struct net *net, struct nlattr *nla, 39 struct nlattr *est, struct tc_action **a, int ovr, 40 int bind, bool rtnl_held, 41 struct netlink_ext_ack *extack) 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, err; 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 err = tcf_idr_check_alloc(tn, &parm->index, a, bind); 63 if (err < 0) 64 return err; 65 exists = err; 66 if (exists && bind) 67 return 0; 68 69 if (!exists) { 70 ret = tcf_idr_create(tn, parm->index, est, a, 71 &act_sample_ops, bind, false); 72 if (ret) { 73 tcf_idr_cleanup(tn, parm->index); 74 return ret; 75 } 76 ret = ACT_P_CREATED; 77 } else if (!ovr) { 78 tcf_idr_release(*a, bind); 79 return -EEXIST; 80 } 81 s = to_sample(*a); 82 83 s->tcf_action = parm->action; 84 s->rate = nla_get_u32(tb[TCA_SAMPLE_RATE]); 85 s->psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]); 86 psample_group = psample_group_get(net, s->psample_group_num); 87 if (!psample_group) { 88 tcf_idr_release(*a, bind); 89 return -ENOMEM; 90 } 91 RCU_INIT_POINTER(s->psample_group, psample_group); 92 93 if (tb[TCA_SAMPLE_TRUNC_SIZE]) { 94 s->truncate = true; 95 s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]); 96 } 97 98 if (ret == ACT_P_CREATED) 99 tcf_idr_insert(tn, *a); 100 return ret; 101 } 102 103 static void tcf_sample_cleanup(struct tc_action *a) 104 { 105 struct tcf_sample *s = to_sample(a); 106 struct psample_group *psample_group; 107 108 psample_group = rtnl_dereference(s->psample_group); 109 RCU_INIT_POINTER(s->psample_group, NULL); 110 if (psample_group) 111 psample_group_put(psample_group); 112 } 113 114 static bool tcf_sample_dev_ok_push(struct net_device *dev) 115 { 116 switch (dev->type) { 117 case ARPHRD_TUNNEL: 118 case ARPHRD_TUNNEL6: 119 case ARPHRD_SIT: 120 case ARPHRD_IPGRE: 121 case ARPHRD_VOID: 122 case ARPHRD_NONE: 123 return false; 124 default: 125 return true; 126 } 127 } 128 129 static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a, 130 struct tcf_result *res) 131 { 132 struct tcf_sample *s = to_sample(a); 133 struct psample_group *psample_group; 134 int retval; 135 int size; 136 int iif; 137 int oif; 138 139 tcf_lastuse_update(&s->tcf_tm); 140 bstats_cpu_update(this_cpu_ptr(s->common.cpu_bstats), skb); 141 retval = READ_ONCE(s->tcf_action); 142 143 rcu_read_lock(); 144 psample_group = rcu_dereference(s->psample_group); 145 146 /* randomly sample packets according to rate */ 147 if (psample_group && (prandom_u32() % s->rate == 0)) { 148 if (!skb_at_tc_ingress(skb)) { 149 iif = skb->skb_iif; 150 oif = skb->dev->ifindex; 151 } else { 152 iif = skb->dev->ifindex; 153 oif = 0; 154 } 155 156 /* on ingress, the mac header gets popped, so push it back */ 157 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) 158 skb_push(skb, skb->mac_len); 159 160 size = s->truncate ? s->trunc_size : skb->len; 161 psample_sample_packet(psample_group, skb, size, iif, oif, 162 s->rate); 163 164 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) 165 skb_pull(skb, skb->mac_len); 166 } 167 168 rcu_read_unlock(); 169 return retval; 170 } 171 172 static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a, 173 int bind, int ref) 174 { 175 unsigned char *b = skb_tail_pointer(skb); 176 struct tcf_sample *s = to_sample(a); 177 struct tc_sample opt = { 178 .index = s->tcf_index, 179 .action = s->tcf_action, 180 .refcnt = refcount_read(&s->tcf_refcnt) - ref, 181 .bindcnt = atomic_read(&s->tcf_bindcnt) - bind, 182 }; 183 struct tcf_t t; 184 185 if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt)) 186 goto nla_put_failure; 187 188 tcf_tm_dump(&t, &s->tcf_tm); 189 if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD)) 190 goto nla_put_failure; 191 192 if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate)) 193 goto nla_put_failure; 194 195 if (s->truncate) 196 if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size)) 197 goto nla_put_failure; 198 199 if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num)) 200 goto nla_put_failure; 201 return skb->len; 202 203 nla_put_failure: 204 nlmsg_trim(skb, b); 205 return -1; 206 } 207 208 static int tcf_sample_walker(struct net *net, struct sk_buff *skb, 209 struct netlink_callback *cb, int type, 210 const struct tc_action_ops *ops, 211 struct netlink_ext_ack *extack) 212 { 213 struct tc_action_net *tn = net_generic(net, sample_net_id); 214 215 return tcf_generic_walker(tn, skb, cb, type, ops, extack); 216 } 217 218 static int tcf_sample_search(struct net *net, struct tc_action **a, u32 index, 219 struct netlink_ext_ack *extack) 220 { 221 struct tc_action_net *tn = net_generic(net, sample_net_id); 222 223 return tcf_idr_search(tn, a, index); 224 } 225 226 static int tcf_sample_delete(struct net *net, u32 index) 227 { 228 struct tc_action_net *tn = net_generic(net, sample_net_id); 229 230 return tcf_idr_delete_index(tn, index); 231 } 232 233 static struct tc_action_ops act_sample_ops = { 234 .kind = "sample", 235 .type = TCA_ACT_SAMPLE, 236 .owner = THIS_MODULE, 237 .act = tcf_sample_act, 238 .dump = tcf_sample_dump, 239 .init = tcf_sample_init, 240 .cleanup = tcf_sample_cleanup, 241 .walk = tcf_sample_walker, 242 .lookup = tcf_sample_search, 243 .delete = tcf_sample_delete, 244 .size = sizeof(struct tcf_sample), 245 }; 246 247 static __net_init int sample_init_net(struct net *net) 248 { 249 struct tc_action_net *tn = net_generic(net, sample_net_id); 250 251 return tc_action_net_init(tn, &act_sample_ops); 252 } 253 254 static void __net_exit sample_exit_net(struct list_head *net_list) 255 { 256 tc_action_net_exit(net_list, sample_net_id); 257 } 258 259 static struct pernet_operations sample_net_ops = { 260 .init = sample_init_net, 261 .exit_batch = sample_exit_net, 262 .id = &sample_net_id, 263 .size = sizeof(struct tc_action_net), 264 }; 265 266 static int __init sample_init_module(void) 267 { 268 return tcf_register_action(&act_sample_ops, &sample_net_ops); 269 } 270 271 static void __exit sample_cleanup_module(void) 272 { 273 tcf_unregister_action(&act_sample_ops, &sample_net_ops); 274 } 275 276 module_init(sample_init_module); 277 module_exit(sample_cleanup_module); 278 279 MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>"); 280 MODULE_DESCRIPTION("Packet sampling action"); 281 MODULE_LICENSE("GPL v2"); 282