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