1 /* 2 * net/sched/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 struct tcf_common *tcf_mirred_ht[MIRRED_TAB_MASK + 1]; 34 static u32 mirred_idx_gen; 35 static DEFINE_RWLOCK(mirred_lock); 36 static LIST_HEAD(mirred_list); 37 38 static struct tcf_hashinfo mirred_hash_info = { 39 .htab = tcf_mirred_ht, 40 .hmask = MIRRED_TAB_MASK, 41 .lock = &mirred_lock, 42 }; 43 44 static int tcf_mirred_release(struct tcf_mirred *m, int bind) 45 { 46 if (m) { 47 if (bind) 48 m->tcf_bindcnt--; 49 m->tcf_refcnt--; 50 if (!m->tcf_bindcnt && m->tcf_refcnt <= 0) { 51 list_del(&m->tcfm_list); 52 if (m->tcfm_dev) 53 dev_put(m->tcfm_dev); 54 tcf_hash_destroy(&m->common, &mirred_hash_info); 55 return 1; 56 } 57 } 58 return 0; 59 } 60 61 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = { 62 [TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) }, 63 }; 64 65 static int tcf_mirred_init(struct net *net, struct nlattr *nla, 66 struct nlattr *est, struct tc_action *a, int ovr, 67 int bind) 68 { 69 struct nlattr *tb[TCA_MIRRED_MAX + 1]; 70 struct tc_mirred *parm; 71 struct tcf_mirred *m; 72 struct tcf_common *pc; 73 struct net_device *dev; 74 int ret, ok_push = 0; 75 76 if (nla == NULL) 77 return -EINVAL; 78 ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy); 79 if (ret < 0) 80 return ret; 81 if (tb[TCA_MIRRED_PARMS] == NULL) 82 return -EINVAL; 83 parm = nla_data(tb[TCA_MIRRED_PARMS]); 84 switch (parm->eaction) { 85 case TCA_EGRESS_MIRROR: 86 case TCA_EGRESS_REDIR: 87 break; 88 default: 89 return -EINVAL; 90 } 91 if (parm->ifindex) { 92 dev = __dev_get_by_index(net, parm->ifindex); 93 if (dev == NULL) 94 return -ENODEV; 95 switch (dev->type) { 96 case ARPHRD_TUNNEL: 97 case ARPHRD_TUNNEL6: 98 case ARPHRD_SIT: 99 case ARPHRD_IPGRE: 100 case ARPHRD_VOID: 101 case ARPHRD_NONE: 102 ok_push = 0; 103 break; 104 default: 105 ok_push = 1; 106 break; 107 } 108 } else { 109 dev = NULL; 110 } 111 112 pc = tcf_hash_check(parm->index, a, bind, &mirred_hash_info); 113 if (!pc) { 114 if (dev == NULL) 115 return -EINVAL; 116 pc = tcf_hash_create(parm->index, est, a, sizeof(*m), bind, 117 &mirred_idx_gen, &mirred_hash_info); 118 if (IS_ERR(pc)) 119 return PTR_ERR(pc); 120 ret = ACT_P_CREATED; 121 } else { 122 if (!ovr) { 123 tcf_mirred_release(to_mirred(pc), bind); 124 return -EEXIST; 125 } 126 } 127 m = to_mirred(pc); 128 129 spin_lock_bh(&m->tcf_lock); 130 m->tcf_action = parm->action; 131 m->tcfm_eaction = parm->eaction; 132 if (dev != NULL) { 133 m->tcfm_ifindex = parm->ifindex; 134 if (ret != ACT_P_CREATED) 135 dev_put(m->tcfm_dev); 136 dev_hold(dev); 137 m->tcfm_dev = dev; 138 m->tcfm_ok_push = ok_push; 139 } 140 spin_unlock_bh(&m->tcf_lock); 141 if (ret == ACT_P_CREATED) { 142 list_add(&m->tcfm_list, &mirred_list); 143 tcf_hash_insert(pc, &mirred_hash_info); 144 } 145 146 return ret; 147 } 148 149 static int tcf_mirred_cleanup(struct tc_action *a, int bind) 150 { 151 struct tcf_mirred *m = a->priv; 152 153 if (m) 154 return tcf_mirred_release(m, bind); 155 return 0; 156 } 157 158 static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a, 159 struct tcf_result *res) 160 { 161 struct tcf_mirred *m = a->priv; 162 struct net_device *dev; 163 struct sk_buff *skb2; 164 u32 at; 165 int retval, err = 1; 166 167 spin_lock(&m->tcf_lock); 168 m->tcf_tm.lastuse = jiffies; 169 bstats_update(&m->tcf_bstats, skb); 170 171 dev = m->tcfm_dev; 172 if (!dev) { 173 printk_once(KERN_NOTICE "tc mirred: target device is gone\n"); 174 goto out; 175 } 176 177 if (!(dev->flags & IFF_UP)) { 178 net_notice_ratelimited("tc mirred to Houston: device %s is down\n", 179 dev->name); 180 goto out; 181 } 182 183 at = G_TC_AT(skb->tc_verd); 184 skb2 = skb_act_clone(skb, GFP_ATOMIC, m->tcf_action); 185 if (skb2 == NULL) 186 goto out; 187 188 if (!(at & AT_EGRESS)) { 189 if (m->tcfm_ok_push) 190 skb_push(skb2, skb2->dev->hard_header_len); 191 } 192 193 /* mirror is always swallowed */ 194 if (m->tcfm_eaction != TCA_EGRESS_MIRROR) 195 skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at); 196 197 skb2->skb_iif = skb->dev->ifindex; 198 skb2->dev = dev; 199 err = dev_queue_xmit(skb2); 200 201 out: 202 if (err) { 203 m->tcf_qstats.overlimits++; 204 if (m->tcfm_eaction != TCA_EGRESS_MIRROR) 205 retval = TC_ACT_SHOT; 206 else 207 retval = m->tcf_action; 208 } else 209 retval = m->tcf_action; 210 spin_unlock(&m->tcf_lock); 211 212 return retval; 213 } 214 215 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) 216 { 217 unsigned char *b = skb_tail_pointer(skb); 218 struct tcf_mirred *m = a->priv; 219 struct tc_mirred opt = { 220 .index = m->tcf_index, 221 .action = m->tcf_action, 222 .refcnt = m->tcf_refcnt - ref, 223 .bindcnt = m->tcf_bindcnt - bind, 224 .eaction = m->tcfm_eaction, 225 .ifindex = m->tcfm_ifindex, 226 }; 227 struct tcf_t t; 228 229 if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt)) 230 goto nla_put_failure; 231 t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install); 232 t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse); 233 t.expires = jiffies_to_clock_t(m->tcf_tm.expires); 234 if (nla_put(skb, TCA_MIRRED_TM, sizeof(t), &t)) 235 goto nla_put_failure; 236 return skb->len; 237 238 nla_put_failure: 239 nlmsg_trim(skb, b); 240 return -1; 241 } 242 243 static int mirred_device_event(struct notifier_block *unused, 244 unsigned long event, void *ptr) 245 { 246 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 247 struct tcf_mirred *m; 248 249 if (event == NETDEV_UNREGISTER) 250 list_for_each_entry(m, &mirred_list, tcfm_list) { 251 if (m->tcfm_dev == dev) { 252 dev_put(dev); 253 m->tcfm_dev = NULL; 254 } 255 } 256 257 return NOTIFY_DONE; 258 } 259 260 static struct notifier_block mirred_device_notifier = { 261 .notifier_call = mirred_device_event, 262 }; 263 264 265 static struct tc_action_ops act_mirred_ops = { 266 .kind = "mirred", 267 .hinfo = &mirred_hash_info, 268 .type = TCA_ACT_MIRRED, 269 .capab = TCA_CAP_NONE, 270 .owner = THIS_MODULE, 271 .act = tcf_mirred, 272 .dump = tcf_mirred_dump, 273 .cleanup = tcf_mirred_cleanup, 274 .lookup = tcf_hash_search, 275 .init = tcf_mirred_init, 276 .walk = tcf_generic_walker 277 }; 278 279 MODULE_AUTHOR("Jamal Hadi Salim(2002)"); 280 MODULE_DESCRIPTION("Device Mirror/redirect actions"); 281 MODULE_LICENSE("GPL"); 282 283 static int __init mirred_init_module(void) 284 { 285 int err = register_netdevice_notifier(&mirred_device_notifier); 286 if (err) 287 return err; 288 289 pr_info("Mirror/redirect action on\n"); 290 return tcf_register_action(&act_mirred_ops); 291 } 292 293 static void __exit mirred_cleanup_module(void) 294 { 295 unregister_netdevice_notifier(&mirred_device_notifier); 296 tcf_unregister_action(&act_mirred_ops); 297 } 298 299 module_init(mirred_init_module); 300 module_exit(mirred_cleanup_module); 301