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 = rcu_dereference_protected(m->tcfm_dev, 1); 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 spin_unlock_bh(&mirred_list_lock); 45 if (dev) 46 dev_put(dev); 47 } 48 49 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = { 50 [TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) }, 51 }; 52 53 static int tcf_mirred_init(struct net *net, struct nlattr *nla, 54 struct nlattr *est, struct tc_action *a, int ovr, 55 int bind) 56 { 57 struct nlattr *tb[TCA_MIRRED_MAX + 1]; 58 struct tc_mirred *parm; 59 struct tcf_mirred *m; 60 struct net_device *dev; 61 int ret, ok_push = 0; 62 63 if (nla == NULL) 64 return -EINVAL; 65 ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy); 66 if (ret < 0) 67 return ret; 68 if (tb[TCA_MIRRED_PARMS] == NULL) 69 return -EINVAL; 70 parm = nla_data(tb[TCA_MIRRED_PARMS]); 71 switch (parm->eaction) { 72 case TCA_EGRESS_MIRROR: 73 case TCA_EGRESS_REDIR: 74 break; 75 default: 76 return -EINVAL; 77 } 78 if (parm->ifindex) { 79 dev = __dev_get_by_index(net, parm->ifindex); 80 if (dev == NULL) 81 return -ENODEV; 82 switch (dev->type) { 83 case ARPHRD_TUNNEL: 84 case ARPHRD_TUNNEL6: 85 case ARPHRD_SIT: 86 case ARPHRD_IPGRE: 87 case ARPHRD_VOID: 88 case ARPHRD_NONE: 89 ok_push = 0; 90 break; 91 default: 92 ok_push = 1; 93 break; 94 } 95 } else { 96 dev = NULL; 97 } 98 99 if (!tcf_hash_check(parm->index, a, bind)) { 100 if (dev == NULL) 101 return -EINVAL; 102 ret = tcf_hash_create(parm->index, est, a, sizeof(*m), 103 bind, true); 104 if (ret) 105 return ret; 106 ret = ACT_P_CREATED; 107 } else { 108 if (bind) 109 return 0; 110 111 tcf_hash_release(a, bind); 112 if (!ovr) 113 return -EEXIST; 114 } 115 m = to_mirred(a); 116 117 ASSERT_RTNL(); 118 m->tcf_action = parm->action; 119 m->tcfm_eaction = parm->eaction; 120 if (dev != NULL) { 121 m->tcfm_ifindex = parm->ifindex; 122 if (ret != ACT_P_CREATED) 123 dev_put(rcu_dereference_protected(m->tcfm_dev, 1)); 124 dev_hold(dev); 125 rcu_assign_pointer(m->tcfm_dev, dev); 126 m->tcfm_ok_push = ok_push; 127 } 128 129 if (ret == ACT_P_CREATED) { 130 spin_lock_bh(&mirred_list_lock); 131 list_add(&m->tcfm_list, &mirred_list); 132 spin_unlock_bh(&mirred_list_lock); 133 tcf_hash_insert(a); 134 } 135 136 return ret; 137 } 138 139 static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a, 140 struct tcf_result *res) 141 { 142 struct tcf_mirred *m = a->priv; 143 struct net_device *dev; 144 struct sk_buff *skb2; 145 int retval, err; 146 u32 at; 147 148 tcf_lastuse_update(&m->tcf_tm); 149 150 bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb); 151 152 rcu_read_lock(); 153 retval = READ_ONCE(m->tcf_action); 154 dev = rcu_dereference(m->tcfm_dev); 155 if (unlikely(!dev)) { 156 pr_notice_once("tc mirred: target device is gone\n"); 157 goto out; 158 } 159 160 if (unlikely(!(dev->flags & IFF_UP))) { 161 net_notice_ratelimited("tc mirred to Houston: device %s is down\n", 162 dev->name); 163 goto out; 164 } 165 166 at = G_TC_AT(skb->tc_verd); 167 skb2 = skb_clone(skb, GFP_ATOMIC); 168 if (!skb2) 169 goto out; 170 171 if (!(at & AT_EGRESS)) { 172 if (m->tcfm_ok_push) 173 skb_push(skb2, skb->mac_len); 174 } 175 176 /* mirror is always swallowed */ 177 if (m->tcfm_eaction != TCA_EGRESS_MIRROR) 178 skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at); 179 180 skb2->skb_iif = skb->dev->ifindex; 181 skb2->dev = dev; 182 skb_sender_cpu_clear(skb2); 183 err = dev_queue_xmit(skb2); 184 185 if (err) { 186 out: 187 qstats_overlimit_inc(this_cpu_ptr(m->common.cpu_qstats)); 188 if (m->tcfm_eaction != TCA_EGRESS_MIRROR) 189 retval = TC_ACT_SHOT; 190 } 191 rcu_read_unlock(); 192 193 return retval; 194 } 195 196 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) 197 { 198 unsigned char *b = skb_tail_pointer(skb); 199 struct tcf_mirred *m = a->priv; 200 struct tc_mirred opt = { 201 .index = m->tcf_index, 202 .action = m->tcf_action, 203 .refcnt = m->tcf_refcnt - ref, 204 .bindcnt = m->tcf_bindcnt - bind, 205 .eaction = m->tcfm_eaction, 206 .ifindex = m->tcfm_ifindex, 207 }; 208 struct tcf_t t; 209 210 if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt)) 211 goto nla_put_failure; 212 t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install); 213 t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse); 214 t.expires = jiffies_to_clock_t(m->tcf_tm.expires); 215 if (nla_put(skb, TCA_MIRRED_TM, sizeof(t), &t)) 216 goto nla_put_failure; 217 return skb->len; 218 219 nla_put_failure: 220 nlmsg_trim(skb, b); 221 return -1; 222 } 223 224 static int mirred_device_event(struct notifier_block *unused, 225 unsigned long event, void *ptr) 226 { 227 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 228 struct tcf_mirred *m; 229 230 ASSERT_RTNL(); 231 if (event == NETDEV_UNREGISTER) { 232 spin_lock_bh(&mirred_list_lock); 233 list_for_each_entry(m, &mirred_list, tcfm_list) { 234 if (rcu_access_pointer(m->tcfm_dev) == dev) { 235 dev_put(dev); 236 /* Note : no rcu grace period necessary, as 237 * net_device are already rcu protected. 238 */ 239 RCU_INIT_POINTER(m->tcfm_dev, NULL); 240 } 241 } 242 spin_unlock_bh(&mirred_list_lock); 243 } 244 245 return NOTIFY_DONE; 246 } 247 248 static struct notifier_block mirred_device_notifier = { 249 .notifier_call = mirred_device_event, 250 }; 251 252 static struct tc_action_ops act_mirred_ops = { 253 .kind = "mirred", 254 .type = TCA_ACT_MIRRED, 255 .owner = THIS_MODULE, 256 .act = tcf_mirred, 257 .dump = tcf_mirred_dump, 258 .cleanup = tcf_mirred_release, 259 .init = tcf_mirred_init, 260 }; 261 262 MODULE_AUTHOR("Jamal Hadi Salim(2002)"); 263 MODULE_DESCRIPTION("Device Mirror/redirect actions"); 264 MODULE_LICENSE("GPL"); 265 266 static int __init mirred_init_module(void) 267 { 268 int err = register_netdevice_notifier(&mirred_device_notifier); 269 if (err) 270 return err; 271 272 pr_info("Mirror/redirect action on\n"); 273 return tcf_register_action(&act_mirred_ops, MIRRED_TAB_MASK); 274 } 275 276 static void __exit mirred_cleanup_module(void) 277 { 278 tcf_unregister_action(&act_mirred_ops); 279 unregister_netdevice_notifier(&mirred_device_notifier); 280 } 281 282 module_init(mirred_init_module); 283 module_exit(mirred_cleanup_module); 284