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 nlattr *nla, struct nlattr *est, 66 struct tc_action *a, int ovr, int bind) 67 { 68 struct nlattr *tb[TCA_MIRRED_MAX + 1]; 69 struct tc_mirred *parm; 70 struct tcf_mirred *m; 71 struct tcf_common *pc; 72 struct net_device *dev; 73 int ret, ok_push = 0; 74 75 if (nla == NULL) 76 return -EINVAL; 77 ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy); 78 if (ret < 0) 79 return ret; 80 if (tb[TCA_MIRRED_PARMS] == NULL) 81 return -EINVAL; 82 parm = nla_data(tb[TCA_MIRRED_PARMS]); 83 switch (parm->eaction) { 84 case TCA_EGRESS_MIRROR: 85 case TCA_EGRESS_REDIR: 86 break; 87 default: 88 return -EINVAL; 89 } 90 if (parm->ifindex) { 91 dev = __dev_get_by_index(&init_net, parm->ifindex); 92 if (dev == NULL) 93 return -ENODEV; 94 switch (dev->type) { 95 case ARPHRD_TUNNEL: 96 case ARPHRD_TUNNEL6: 97 case ARPHRD_SIT: 98 case ARPHRD_IPGRE: 99 case ARPHRD_VOID: 100 case ARPHRD_NONE: 101 ok_push = 0; 102 break; 103 default: 104 ok_push = 1; 105 break; 106 } 107 } else { 108 dev = NULL; 109 } 110 111 pc = tcf_hash_check(parm->index, a, bind, &mirred_hash_info); 112 if (!pc) { 113 if (dev == NULL) 114 return -EINVAL; 115 pc = tcf_hash_create(parm->index, est, a, sizeof(*m), bind, 116 &mirred_idx_gen, &mirred_hash_info); 117 if (IS_ERR(pc)) 118 return PTR_ERR(pc); 119 ret = ACT_P_CREATED; 120 } else { 121 if (!ovr) { 122 tcf_mirred_release(to_mirred(pc), bind); 123 return -EEXIST; 124 } 125 } 126 m = to_mirred(pc); 127 128 spin_lock_bh(&m->tcf_lock); 129 m->tcf_action = parm->action; 130 m->tcfm_eaction = parm->eaction; 131 if (dev != NULL) { 132 m->tcfm_ifindex = parm->ifindex; 133 if (ret != ACT_P_CREATED) 134 dev_put(m->tcfm_dev); 135 dev_hold(dev); 136 m->tcfm_dev = dev; 137 m->tcfm_ok_push = ok_push; 138 } 139 spin_unlock_bh(&m->tcf_lock); 140 if (ret == ACT_P_CREATED) { 141 list_add(&m->tcfm_list, &mirred_list); 142 tcf_hash_insert(pc, &mirred_hash_info); 143 } 144 145 return ret; 146 } 147 148 static int tcf_mirred_cleanup(struct tc_action *a, int bind) 149 { 150 struct tcf_mirred *m = a->priv; 151 152 if (m) 153 return tcf_mirred_release(m, bind); 154 return 0; 155 } 156 157 static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a, 158 struct tcf_result *res) 159 { 160 struct tcf_mirred *m = a->priv; 161 struct net_device *dev; 162 struct sk_buff *skb2; 163 u32 at; 164 int retval, err = 1; 165 166 spin_lock(&m->tcf_lock); 167 m->tcf_tm.lastuse = jiffies; 168 bstats_update(&m->tcf_bstats, skb); 169 170 dev = m->tcfm_dev; 171 if (!dev) { 172 printk_once(KERN_NOTICE "tc mirred: target device is gone\n"); 173 goto out; 174 } 175 176 if (!(dev->flags & IFF_UP)) { 177 if (net_ratelimit()) 178 pr_notice("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 /* should we be asking for packet to be dropped? 205 * may make sense for redirect case only 206 */ 207 retval = TC_ACT_SHOT; 208 } else { 209 retval = m->tcf_action; 210 } 211 spin_unlock(&m->tcf_lock); 212 213 return retval; 214 } 215 216 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) 217 { 218 unsigned char *b = skb_tail_pointer(skb); 219 struct tcf_mirred *m = a->priv; 220 struct tc_mirred opt = { 221 .index = m->tcf_index, 222 .action = m->tcf_action, 223 .refcnt = m->tcf_refcnt - ref, 224 .bindcnt = m->tcf_bindcnt - bind, 225 .eaction = m->tcfm_eaction, 226 .ifindex = m->tcfm_ifindex, 227 }; 228 struct tcf_t t; 229 230 NLA_PUT(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt); 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 NLA_PUT(skb, TCA_MIRRED_TM, sizeof(t), &t); 235 return skb->len; 236 237 nla_put_failure: 238 nlmsg_trim(skb, b); 239 return -1; 240 } 241 242 static int mirred_device_event(struct notifier_block *unused, 243 unsigned long event, void *ptr) 244 { 245 struct net_device *dev = ptr; 246 struct tcf_mirred *m; 247 248 if (event == NETDEV_UNREGISTER) 249 list_for_each_entry(m, &mirred_list, tcfm_list) { 250 if (m->tcfm_dev == dev) { 251 dev_put(dev); 252 m->tcfm_dev = NULL; 253 } 254 } 255 256 return NOTIFY_DONE; 257 } 258 259 static struct notifier_block mirred_device_notifier = { 260 .notifier_call = mirred_device_event, 261 }; 262 263 264 static struct tc_action_ops act_mirred_ops = { 265 .kind = "mirred", 266 .hinfo = &mirred_hash_info, 267 .type = TCA_ACT_MIRRED, 268 .capab = TCA_CAP_NONE, 269 .owner = THIS_MODULE, 270 .act = tcf_mirred, 271 .dump = tcf_mirred_dump, 272 .cleanup = tcf_mirred_cleanup, 273 .lookup = tcf_hash_search, 274 .init = tcf_mirred_init, 275 .walk = tcf_generic_walker 276 }; 277 278 MODULE_AUTHOR("Jamal Hadi Salim(2002)"); 279 MODULE_DESCRIPTION("Device Mirror/redirect actions"); 280 MODULE_LICENSE("GPL"); 281 282 static int __init mirred_init_module(void) 283 { 284 int err = register_netdevice_notifier(&mirred_device_notifier); 285 if (err) 286 return err; 287 288 pr_info("Mirror/redirect action on\n"); 289 return tcf_register_action(&act_mirred_ops); 290 } 291 292 static void __exit mirred_cleanup_module(void) 293 { 294 unregister_netdevice_notifier(&mirred_device_notifier); 295 tcf_unregister_action(&act_mirred_ops); 296 } 297 298 module_init(mirred_init_module); 299 module_exit(mirred_cleanup_module); 300