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 (!ovr) { 102 tcf_hash_release(a, bind); 103 return -EEXIST; 104 } 105 } 106 m = to_mirred(a); 107 108 spin_lock_bh(&m->tcf_lock); 109 m->tcf_action = parm->action; 110 m->tcfm_eaction = parm->eaction; 111 if (dev != NULL) { 112 m->tcfm_ifindex = parm->ifindex; 113 if (ret != ACT_P_CREATED) 114 dev_put(m->tcfm_dev); 115 dev_hold(dev); 116 m->tcfm_dev = dev; 117 m->tcfm_ok_push = ok_push; 118 } 119 spin_unlock_bh(&m->tcf_lock); 120 if (ret == ACT_P_CREATED) { 121 list_add(&m->tcfm_list, &mirred_list); 122 tcf_hash_insert(a); 123 } 124 125 return ret; 126 } 127 128 static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a, 129 struct tcf_result *res) 130 { 131 struct tcf_mirred *m = a->priv; 132 struct net_device *dev; 133 struct sk_buff *skb2; 134 u32 at; 135 int retval, err = 1; 136 137 spin_lock(&m->tcf_lock); 138 m->tcf_tm.lastuse = jiffies; 139 bstats_update(&m->tcf_bstats, skb); 140 141 dev = m->tcfm_dev; 142 if (!dev) { 143 printk_once(KERN_NOTICE "tc mirred: target device is gone\n"); 144 goto out; 145 } 146 147 if (!(dev->flags & IFF_UP)) { 148 net_notice_ratelimited("tc mirred to Houston: device %s is down\n", 149 dev->name); 150 goto out; 151 } 152 153 at = G_TC_AT(skb->tc_verd); 154 skb2 = skb_act_clone(skb, GFP_ATOMIC, m->tcf_action); 155 if (skb2 == NULL) 156 goto out; 157 158 if (!(at & AT_EGRESS)) { 159 if (m->tcfm_ok_push) 160 skb_push(skb2, skb2->dev->hard_header_len); 161 } 162 163 /* mirror is always swallowed */ 164 if (m->tcfm_eaction != TCA_EGRESS_MIRROR) 165 skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at); 166 167 skb2->skb_iif = skb->dev->ifindex; 168 skb2->dev = dev; 169 err = dev_queue_xmit(skb2); 170 171 out: 172 if (err) { 173 m->tcf_qstats.overlimits++; 174 if (m->tcfm_eaction != TCA_EGRESS_MIRROR) 175 retval = TC_ACT_SHOT; 176 else 177 retval = m->tcf_action; 178 } else 179 retval = m->tcf_action; 180 spin_unlock(&m->tcf_lock); 181 182 return retval; 183 } 184 185 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) 186 { 187 unsigned char *b = skb_tail_pointer(skb); 188 struct tcf_mirred *m = a->priv; 189 struct tc_mirred opt = { 190 .index = m->tcf_index, 191 .action = m->tcf_action, 192 .refcnt = m->tcf_refcnt - ref, 193 .bindcnt = m->tcf_bindcnt - bind, 194 .eaction = m->tcfm_eaction, 195 .ifindex = m->tcfm_ifindex, 196 }; 197 struct tcf_t t; 198 199 if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt)) 200 goto nla_put_failure; 201 t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install); 202 t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse); 203 t.expires = jiffies_to_clock_t(m->tcf_tm.expires); 204 if (nla_put(skb, TCA_MIRRED_TM, sizeof(t), &t)) 205 goto nla_put_failure; 206 return skb->len; 207 208 nla_put_failure: 209 nlmsg_trim(skb, b); 210 return -1; 211 } 212 213 static int mirred_device_event(struct notifier_block *unused, 214 unsigned long event, void *ptr) 215 { 216 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 217 struct tcf_mirred *m; 218 219 if (event == NETDEV_UNREGISTER) 220 list_for_each_entry(m, &mirred_list, tcfm_list) { 221 spin_lock_bh(&m->tcf_lock); 222 if (m->tcfm_dev == dev) { 223 dev_put(dev); 224 m->tcfm_dev = NULL; 225 } 226 spin_unlock_bh(&m->tcf_lock); 227 } 228 229 return NOTIFY_DONE; 230 } 231 232 static struct notifier_block mirred_device_notifier = { 233 .notifier_call = mirred_device_event, 234 }; 235 236 static struct tc_action_ops act_mirred_ops = { 237 .kind = "mirred", 238 .type = TCA_ACT_MIRRED, 239 .owner = THIS_MODULE, 240 .act = tcf_mirred, 241 .dump = tcf_mirred_dump, 242 .cleanup = tcf_mirred_release, 243 .init = tcf_mirred_init, 244 }; 245 246 MODULE_AUTHOR("Jamal Hadi Salim(2002)"); 247 MODULE_DESCRIPTION("Device Mirror/redirect actions"); 248 MODULE_LICENSE("GPL"); 249 250 static int __init mirred_init_module(void) 251 { 252 int err = register_netdevice_notifier(&mirred_device_notifier); 253 if (err) 254 return err; 255 256 pr_info("Mirror/redirect action on\n"); 257 return tcf_register_action(&act_mirred_ops, MIRRED_TAB_MASK); 258 } 259 260 static void __exit mirred_cleanup_module(void) 261 { 262 tcf_unregister_action(&act_mirred_ops); 263 unregister_netdevice_notifier(&mirred_device_notifier); 264 } 265 266 module_init(mirred_init_module); 267 module_exit(mirred_cleanup_module); 268