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 35 static void tcf_mirred_release(struct tc_action *a, int bind) 36 { 37 struct tcf_mirred *m = to_mirred(a); 38 struct net_device *dev = rcu_dereference_protected(m->tcfm_dev, 1); 39 40 list_del(&m->tcfm_list); 41 if (dev) 42 dev_put(dev); 43 } 44 45 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = { 46 [TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) }, 47 }; 48 49 static int tcf_mirred_init(struct net *net, struct nlattr *nla, 50 struct nlattr *est, struct tc_action *a, int ovr, 51 int bind) 52 { 53 struct nlattr *tb[TCA_MIRRED_MAX + 1]; 54 struct tc_mirred *parm; 55 struct tcf_mirred *m; 56 struct net_device *dev; 57 int ret, ok_push = 0; 58 59 if (nla == NULL) 60 return -EINVAL; 61 ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy); 62 if (ret < 0) 63 return ret; 64 if (tb[TCA_MIRRED_PARMS] == NULL) 65 return -EINVAL; 66 parm = nla_data(tb[TCA_MIRRED_PARMS]); 67 switch (parm->eaction) { 68 case TCA_EGRESS_MIRROR: 69 case TCA_EGRESS_REDIR: 70 break; 71 default: 72 return -EINVAL; 73 } 74 if (parm->ifindex) { 75 dev = __dev_get_by_index(net, parm->ifindex); 76 if (dev == NULL) 77 return -ENODEV; 78 switch (dev->type) { 79 case ARPHRD_TUNNEL: 80 case ARPHRD_TUNNEL6: 81 case ARPHRD_SIT: 82 case ARPHRD_IPGRE: 83 case ARPHRD_VOID: 84 case ARPHRD_NONE: 85 ok_push = 0; 86 break; 87 default: 88 ok_push = 1; 89 break; 90 } 91 } else { 92 dev = NULL; 93 } 94 95 if (!tcf_hash_check(parm->index, a, bind)) { 96 if (dev == NULL) 97 return -EINVAL; 98 ret = tcf_hash_create(parm->index, est, a, sizeof(*m), 99 bind, true); 100 if (ret) 101 return ret; 102 ret = ACT_P_CREATED; 103 } else { 104 if (bind) 105 return 0; 106 if (!ovr) { 107 tcf_hash_release(a, bind); 108 return -EEXIST; 109 } 110 } 111 m = to_mirred(a); 112 113 ASSERT_RTNL(); 114 m->tcf_action = parm->action; 115 m->tcfm_eaction = parm->eaction; 116 if (dev != NULL) { 117 m->tcfm_ifindex = parm->ifindex; 118 if (ret != ACT_P_CREATED) 119 dev_put(rcu_dereference_protected(m->tcfm_dev, 1)); 120 dev_hold(dev); 121 rcu_assign_pointer(m->tcfm_dev, dev); 122 m->tcfm_ok_push = ok_push; 123 } 124 125 if (ret == ACT_P_CREATED) { 126 list_add(&m->tcfm_list, &mirred_list); 127 tcf_hash_insert(a); 128 } 129 130 return ret; 131 } 132 133 static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a, 134 struct tcf_result *res) 135 { 136 struct tcf_mirred *m = a->priv; 137 struct net_device *dev; 138 struct sk_buff *skb2; 139 int retval, err; 140 u32 at; 141 142 tcf_lastuse_update(&m->tcf_tm); 143 144 bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb); 145 146 rcu_read_lock(); 147 retval = READ_ONCE(m->tcf_action); 148 dev = rcu_dereference(m->tcfm_dev); 149 if (unlikely(!dev)) { 150 pr_notice_once("tc mirred: target device is gone\n"); 151 goto out; 152 } 153 154 if (unlikely(!(dev->flags & IFF_UP))) { 155 net_notice_ratelimited("tc mirred to Houston: device %s is down\n", 156 dev->name); 157 goto out; 158 } 159 160 at = G_TC_AT(skb->tc_verd); 161 skb2 = skb_clone(skb, GFP_ATOMIC); 162 if (!skb2) 163 goto out; 164 165 if (!(at & AT_EGRESS)) { 166 if (m->tcfm_ok_push) 167 skb_push(skb2, skb->mac_len); 168 } 169 170 /* mirror is always swallowed */ 171 if (m->tcfm_eaction != TCA_EGRESS_MIRROR) 172 skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at); 173 174 skb2->skb_iif = skb->dev->ifindex; 175 skb2->dev = dev; 176 err = dev_queue_xmit(skb2); 177 178 if (err) { 179 out: 180 qstats_overlimit_inc(this_cpu_ptr(m->common.cpu_qstats)); 181 if (m->tcfm_eaction != TCA_EGRESS_MIRROR) 182 retval = TC_ACT_SHOT; 183 } 184 rcu_read_unlock(); 185 186 return retval; 187 } 188 189 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) 190 { 191 unsigned char *b = skb_tail_pointer(skb); 192 struct tcf_mirred *m = a->priv; 193 struct tc_mirred opt = { 194 .index = m->tcf_index, 195 .action = m->tcf_action, 196 .refcnt = m->tcf_refcnt - ref, 197 .bindcnt = m->tcf_bindcnt - bind, 198 .eaction = m->tcfm_eaction, 199 .ifindex = m->tcfm_ifindex, 200 }; 201 struct tcf_t t; 202 203 if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt)) 204 goto nla_put_failure; 205 t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install); 206 t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse); 207 t.expires = jiffies_to_clock_t(m->tcf_tm.expires); 208 if (nla_put(skb, TCA_MIRRED_TM, sizeof(t), &t)) 209 goto nla_put_failure; 210 return skb->len; 211 212 nla_put_failure: 213 nlmsg_trim(skb, b); 214 return -1; 215 } 216 217 static int mirred_device_event(struct notifier_block *unused, 218 unsigned long event, void *ptr) 219 { 220 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 221 struct tcf_mirred *m; 222 223 ASSERT_RTNL(); 224 if (event == NETDEV_UNREGISTER) 225 list_for_each_entry(m, &mirred_list, tcfm_list) { 226 if (rcu_access_pointer(m->tcfm_dev) == dev) { 227 dev_put(dev); 228 /* Note : no rcu grace period necessary, as 229 * net_device are already rcu protected. 230 */ 231 RCU_INIT_POINTER(m->tcfm_dev, NULL); 232 } 233 } 234 235 return NOTIFY_DONE; 236 } 237 238 static struct notifier_block mirred_device_notifier = { 239 .notifier_call = mirred_device_event, 240 }; 241 242 static struct tc_action_ops act_mirred_ops = { 243 .kind = "mirred", 244 .type = TCA_ACT_MIRRED, 245 .owner = THIS_MODULE, 246 .act = tcf_mirred, 247 .dump = tcf_mirred_dump, 248 .cleanup = tcf_mirred_release, 249 .init = tcf_mirred_init, 250 }; 251 252 MODULE_AUTHOR("Jamal Hadi Salim(2002)"); 253 MODULE_DESCRIPTION("Device Mirror/redirect actions"); 254 MODULE_LICENSE("GPL"); 255 256 static int __init mirred_init_module(void) 257 { 258 int err = register_netdevice_notifier(&mirred_device_notifier); 259 if (err) 260 return err; 261 262 pr_info("Mirror/redirect action on\n"); 263 return tcf_register_action(&act_mirred_ops, MIRRED_TAB_MASK); 264 } 265 266 static void __exit mirred_cleanup_module(void) 267 { 268 tcf_unregister_action(&act_mirred_ops); 269 unregister_netdevice_notifier(&mirred_device_notifier); 270 } 271 272 module_init(mirred_init_module); 273 module_exit(mirred_cleanup_module); 274