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