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