| 1 | /* |
| 2 | * net/sched/act_mirred.c packet mirroring and redirect actions |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or |
| 5 | * modify it under the terms of the GNU General Public License |
| 6 | * as published by the Free Software Foundation; either version |
| 7 | * 2 of the License, or (at your option) any later version. |
| 8 | * |
| 9 | * Authors: Jamal Hadi Salim (2002-4) |
| 10 | * |
| 11 | * TODO: Add ingress support (and socket redirect support) |
| 12 | * |
| 13 | */ |
| 14 | |
| 15 | #include <linux/types.h> |
| 16 | #include <linux/kernel.h> |
| 17 | #include <linux/string.h> |
| 18 | #include <linux/errno.h> |
| 19 | #include <linux/skbuff.h> |
| 20 | #include <linux/rtnetlink.h> |
| 21 | #include <linux/module.h> |
| 22 | #include <linux/init.h> |
| 23 | #include <linux/gfp.h> |
| 24 | #include <net/net_namespace.h> |
| 25 | #include <net/netlink.h> |
| 26 | #include <net/pkt_sched.h> |
| 27 | #include <linux/tc_act/tc_mirred.h> |
| 28 | #include <net/tc_act/tc_mirred.h> |
| 29 | |
| 30 | #include <linux/if_arp.h> |
| 31 | |
| 32 | #define MIRRED_TAB_MASK 7 |
| 33 | static LIST_HEAD(mirred_list); |
| 34 | static DEFINE_SPINLOCK(mirred_list_lock); |
| 35 | |
| 36 | static void tcf_mirred_release(struct tc_action *a, int bind) |
| 37 | { |
| 38 | struct tcf_mirred *m = to_mirred(a); |
| 39 | struct net_device *dev; |
| 40 | |
| 41 | /* We could be called either in a RCU callback or with RTNL lock held. */ |
| 42 | spin_lock_bh(&mirred_list_lock); |
| 43 | list_del(&m->tcfm_list); |
| 44 | dev = rcu_dereference_protected(m->tcfm_dev, 1); |
| 45 | if (dev) |
| 46 | dev_put(dev); |
| 47 | spin_unlock_bh(&mirred_list_lock); |
| 48 | } |
| 49 | |
| 50 | static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = { |
| 51 | [TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) }, |
| 52 | }; |
| 53 | |
| 54 | static int mirred_net_id; |
| 55 | static struct tc_action_ops act_mirred_ops; |
| 56 | |
| 57 | static int tcf_mirred_init(struct net *net, struct nlattr *nla, |
| 58 | struct nlattr *est, struct tc_action **a, int ovr, |
| 59 | int bind) |
| 60 | { |
| 61 | struct tc_action_net *tn = net_generic(net, mirred_net_id); |
| 62 | struct nlattr *tb[TCA_MIRRED_MAX + 1]; |
| 63 | struct tc_mirred *parm; |
| 64 | struct tcf_mirred *m; |
| 65 | struct net_device *dev; |
| 66 | int ret, ok_push = 0; |
| 67 | bool exists = false; |
| 68 | |
| 69 | if (nla == NULL) |
| 70 | return -EINVAL; |
| 71 | ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy); |
| 72 | if (ret < 0) |
| 73 | return ret; |
| 74 | if (tb[TCA_MIRRED_PARMS] == NULL) |
| 75 | return -EINVAL; |
| 76 | parm = nla_data(tb[TCA_MIRRED_PARMS]); |
| 77 | |
| 78 | exists = tcf_hash_check(tn, parm->index, a, bind); |
| 79 | if (exists && bind) |
| 80 | return 0; |
| 81 | |
| 82 | switch (parm->eaction) { |
| 83 | case TCA_EGRESS_MIRROR: |
| 84 | case TCA_EGRESS_REDIR: |
| 85 | break; |
| 86 | default: |
| 87 | if (exists) |
| 88 | tcf_hash_release(*a, bind); |
| 89 | return -EINVAL; |
| 90 | } |
| 91 | if (parm->ifindex) { |
| 92 | dev = __dev_get_by_index(net, parm->ifindex); |
| 93 | if (dev == NULL) { |
| 94 | if (exists) |
| 95 | tcf_hash_release(*a, bind); |
| 96 | return -ENODEV; |
| 97 | } |
| 98 | switch (dev->type) { |
| 99 | case ARPHRD_TUNNEL: |
| 100 | case ARPHRD_TUNNEL6: |
| 101 | case ARPHRD_SIT: |
| 102 | case ARPHRD_IPGRE: |
| 103 | case ARPHRD_VOID: |
| 104 | case ARPHRD_NONE: |
| 105 | ok_push = 0; |
| 106 | break; |
| 107 | default: |
| 108 | ok_push = 1; |
| 109 | break; |
| 110 | } |
| 111 | } else { |
| 112 | dev = NULL; |
| 113 | } |
| 114 | |
| 115 | if (!exists) { |
| 116 | if (dev == NULL) |
| 117 | return -EINVAL; |
| 118 | ret = tcf_hash_create(tn, parm->index, est, a, |
| 119 | &act_mirred_ops, bind, true); |
| 120 | if (ret) |
| 121 | return ret; |
| 122 | ret = ACT_P_CREATED; |
| 123 | } else { |
| 124 | tcf_hash_release(*a, bind); |
| 125 | if (!ovr) |
| 126 | return -EEXIST; |
| 127 | } |
| 128 | m = to_mirred(*a); |
| 129 | |
| 130 | ASSERT_RTNL(); |
| 131 | m->tcf_action = parm->action; |
| 132 | m->tcfm_eaction = parm->eaction; |
| 133 | if (dev != NULL) { |
| 134 | m->tcfm_ifindex = parm->ifindex; |
| 135 | if (ret != ACT_P_CREATED) |
| 136 | dev_put(rcu_dereference_protected(m->tcfm_dev, 1)); |
| 137 | dev_hold(dev); |
| 138 | rcu_assign_pointer(m->tcfm_dev, dev); |
| 139 | m->tcfm_ok_push = ok_push; |
| 140 | } |
| 141 | |
| 142 | if (ret == ACT_P_CREATED) { |
| 143 | spin_lock_bh(&mirred_list_lock); |
| 144 | list_add(&m->tcfm_list, &mirred_list); |
| 145 | spin_unlock_bh(&mirred_list_lock); |
| 146 | tcf_hash_insert(tn, *a); |
| 147 | } |
| 148 | |
| 149 | return ret; |
| 150 | } |
| 151 | |
| 152 | static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a, |
| 153 | struct tcf_result *res) |
| 154 | { |
| 155 | struct tcf_mirred *m = to_mirred(a); |
| 156 | struct net_device *dev; |
| 157 | struct sk_buff *skb2; |
| 158 | int retval, err; |
| 159 | u32 at; |
| 160 | |
| 161 | tcf_lastuse_update(&m->tcf_tm); |
| 162 | bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb); |
| 163 | |
| 164 | rcu_read_lock(); |
| 165 | retval = READ_ONCE(m->tcf_action); |
| 166 | dev = rcu_dereference(m->tcfm_dev); |
| 167 | if (unlikely(!dev)) { |
| 168 | pr_notice_once("tc mirred: target device is gone\n"); |
| 169 | goto out; |
| 170 | } |
| 171 | |
| 172 | if (unlikely(!(dev->flags & IFF_UP))) { |
| 173 | net_notice_ratelimited("tc mirred to Houston: device %s is down\n", |
| 174 | dev->name); |
| 175 | goto out; |
| 176 | } |
| 177 | |
| 178 | at = G_TC_AT(skb->tc_verd); |
| 179 | skb2 = skb_clone(skb, GFP_ATOMIC); |
| 180 | if (!skb2) |
| 181 | goto out; |
| 182 | |
| 183 | if (!(at & AT_EGRESS)) { |
| 184 | if (m->tcfm_ok_push) |
| 185 | skb_push_rcsum(skb2, skb->mac_len); |
| 186 | } |
| 187 | |
| 188 | /* mirror is always swallowed */ |
| 189 | if (m->tcfm_eaction != TCA_EGRESS_MIRROR) |
| 190 | skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at); |
| 191 | |
| 192 | skb2->skb_iif = skb->dev->ifindex; |
| 193 | skb2->dev = dev; |
| 194 | err = dev_queue_xmit(skb2); |
| 195 | |
| 196 | if (err) { |
| 197 | out: |
| 198 | qstats_overlimit_inc(this_cpu_ptr(m->common.cpu_qstats)); |
| 199 | if (m->tcfm_eaction != TCA_EGRESS_MIRROR) |
| 200 | retval = TC_ACT_SHOT; |
| 201 | } |
| 202 | rcu_read_unlock(); |
| 203 | |
| 204 | return retval; |
| 205 | } |
| 206 | |
| 207 | static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) |
| 208 | { |
| 209 | unsigned char *b = skb_tail_pointer(skb); |
| 210 | struct tcf_mirred *m = to_mirred(a); |
| 211 | struct tc_mirred opt = { |
| 212 | .index = m->tcf_index, |
| 213 | .action = m->tcf_action, |
| 214 | .refcnt = m->tcf_refcnt - ref, |
| 215 | .bindcnt = m->tcf_bindcnt - bind, |
| 216 | .eaction = m->tcfm_eaction, |
| 217 | .ifindex = m->tcfm_ifindex, |
| 218 | }; |
| 219 | struct tcf_t t; |
| 220 | |
| 221 | if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt)) |
| 222 | goto nla_put_failure; |
| 223 | |
| 224 | tcf_tm_dump(&t, &m->tcf_tm); |
| 225 | if (nla_put_64bit(skb, TCA_MIRRED_TM, sizeof(t), &t, TCA_MIRRED_PAD)) |
| 226 | goto nla_put_failure; |
| 227 | return skb->len; |
| 228 | |
| 229 | nla_put_failure: |
| 230 | nlmsg_trim(skb, b); |
| 231 | return -1; |
| 232 | } |
| 233 | |
| 234 | static int tcf_mirred_walker(struct net *net, struct sk_buff *skb, |
| 235 | struct netlink_callback *cb, int type, |
| 236 | const struct tc_action_ops *ops) |
| 237 | { |
| 238 | struct tc_action_net *tn = net_generic(net, mirred_net_id); |
| 239 | |
| 240 | return tcf_generic_walker(tn, skb, cb, type, ops); |
| 241 | } |
| 242 | |
| 243 | static int tcf_mirred_search(struct net *net, struct tc_action **a, u32 index) |
| 244 | { |
| 245 | struct tc_action_net *tn = net_generic(net, mirred_net_id); |
| 246 | |
| 247 | return tcf_hash_search(tn, a, index); |
| 248 | } |
| 249 | |
| 250 | static int mirred_device_event(struct notifier_block *unused, |
| 251 | unsigned long event, void *ptr) |
| 252 | { |
| 253 | struct net_device *dev = netdev_notifier_info_to_dev(ptr); |
| 254 | struct tcf_mirred *m; |
| 255 | |
| 256 | ASSERT_RTNL(); |
| 257 | if (event == NETDEV_UNREGISTER) { |
| 258 | spin_lock_bh(&mirred_list_lock); |
| 259 | list_for_each_entry(m, &mirred_list, tcfm_list) { |
| 260 | if (rcu_access_pointer(m->tcfm_dev) == dev) { |
| 261 | dev_put(dev); |
| 262 | /* Note : no rcu grace period necessary, as |
| 263 | * net_device are already rcu protected. |
| 264 | */ |
| 265 | RCU_INIT_POINTER(m->tcfm_dev, NULL); |
| 266 | } |
| 267 | } |
| 268 | spin_unlock_bh(&mirred_list_lock); |
| 269 | } |
| 270 | |
| 271 | return NOTIFY_DONE; |
| 272 | } |
| 273 | |
| 274 | static struct notifier_block mirred_device_notifier = { |
| 275 | .notifier_call = mirred_device_event, |
| 276 | }; |
| 277 | |
| 278 | static struct tc_action_ops act_mirred_ops = { |
| 279 | .kind = "mirred", |
| 280 | .type = TCA_ACT_MIRRED, |
| 281 | .owner = THIS_MODULE, |
| 282 | .act = tcf_mirred, |
| 283 | .dump = tcf_mirred_dump, |
| 284 | .cleanup = tcf_mirred_release, |
| 285 | .init = tcf_mirred_init, |
| 286 | .walk = tcf_mirred_walker, |
| 287 | .lookup = tcf_mirred_search, |
| 288 | .size = sizeof(struct tcf_mirred), |
| 289 | }; |
| 290 | |
| 291 | static __net_init int mirred_init_net(struct net *net) |
| 292 | { |
| 293 | struct tc_action_net *tn = net_generic(net, mirred_net_id); |
| 294 | |
| 295 | return tc_action_net_init(tn, &act_mirred_ops, MIRRED_TAB_MASK); |
| 296 | } |
| 297 | |
| 298 | static void __net_exit mirred_exit_net(struct net *net) |
| 299 | { |
| 300 | struct tc_action_net *tn = net_generic(net, mirred_net_id); |
| 301 | |
| 302 | tc_action_net_exit(tn); |
| 303 | } |
| 304 | |
| 305 | static struct pernet_operations mirred_net_ops = { |
| 306 | .init = mirred_init_net, |
| 307 | .exit = mirred_exit_net, |
| 308 | .id = &mirred_net_id, |
| 309 | .size = sizeof(struct tc_action_net), |
| 310 | }; |
| 311 | |
| 312 | MODULE_AUTHOR("Jamal Hadi Salim(2002)"); |
| 313 | MODULE_DESCRIPTION("Device Mirror/redirect actions"); |
| 314 | MODULE_LICENSE("GPL"); |
| 315 | |
| 316 | static int __init mirred_init_module(void) |
| 317 | { |
| 318 | int err = register_netdevice_notifier(&mirred_device_notifier); |
| 319 | if (err) |
| 320 | return err; |
| 321 | |
| 322 | pr_info("Mirror/redirect action on\n"); |
| 323 | return tcf_register_action(&act_mirred_ops, &mirred_net_ops); |
| 324 | } |
| 325 | |
| 326 | static void __exit mirred_cleanup_module(void) |
| 327 | { |
| 328 | tcf_unregister_action(&act_mirred_ops, &mirred_net_ops); |
| 329 | unregister_netdevice_notifier(&mirred_device_notifier); |
| 330 | } |
| 331 | |
| 332 | module_init(mirred_init_module); |
| 333 | module_exit(mirred_cleanup_module); |