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