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 <net/net_namespace.h> 24 #include <net/netlink.h> 25 #include <net/pkt_sched.h> 26 #include <linux/tc_act/tc_mirred.h> 27 #include <net/tc_act/tc_mirred.h> 28 29 #include <linux/if_arp.h> 30 31 #define MIRRED_TAB_MASK 7 32 static struct tcf_common *tcf_mirred_ht[MIRRED_TAB_MASK + 1]; 33 static u32 mirred_idx_gen; 34 static DEFINE_RWLOCK(mirred_lock); 35 36 static struct tcf_hashinfo mirred_hash_info = { 37 .htab = tcf_mirred_ht, 38 .hmask = MIRRED_TAB_MASK, 39 .lock = &mirred_lock, 40 }; 41 42 static inline int tcf_mirred_release(struct tcf_mirred *m, int bind) 43 { 44 if (m) { 45 if (bind) 46 m->tcf_bindcnt--; 47 m->tcf_refcnt--; 48 if(!m->tcf_bindcnt && m->tcf_refcnt <= 0) { 49 dev_put(m->tcfm_dev); 50 tcf_hash_destroy(&m->common, &mirred_hash_info); 51 return 1; 52 } 53 } 54 return 0; 55 } 56 57 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = { 58 [TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) }, 59 }; 60 61 static int tcf_mirred_init(struct nlattr *nla, struct nlattr *est, 62 struct tc_action *a, int ovr, int bind) 63 { 64 struct nlattr *tb[TCA_MIRRED_MAX + 1]; 65 struct tc_mirred *parm; 66 struct tcf_mirred *m; 67 struct tcf_common *pc; 68 struct net_device *dev = NULL; 69 int ret = 0, err; 70 int ok_push = 0; 71 72 if (nla == NULL) 73 return -EINVAL; 74 75 err = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy); 76 if (err < 0) 77 return err; 78 79 if (tb[TCA_MIRRED_PARMS] == NULL) 80 return -EINVAL; 81 parm = nla_data(tb[TCA_MIRRED_PARMS]); 82 83 if (parm->ifindex) { 84 dev = __dev_get_by_index(&init_net, parm->ifindex); 85 if (dev == NULL) 86 return -ENODEV; 87 switch (dev->type) { 88 case ARPHRD_TUNNEL: 89 case ARPHRD_TUNNEL6: 90 case ARPHRD_SIT: 91 case ARPHRD_IPGRE: 92 case ARPHRD_VOID: 93 case ARPHRD_NONE: 94 ok_push = 0; 95 break; 96 default: 97 ok_push = 1; 98 break; 99 } 100 } 101 102 pc = tcf_hash_check(parm->index, a, bind, &mirred_hash_info); 103 if (!pc) { 104 if (!parm->ifindex) 105 return -EINVAL; 106 pc = tcf_hash_create(parm->index, est, a, sizeof(*m), bind, 107 &mirred_idx_gen, &mirred_hash_info); 108 if (unlikely(!pc)) 109 return -ENOMEM; 110 ret = ACT_P_CREATED; 111 } else { 112 if (!ovr) { 113 tcf_mirred_release(to_mirred(pc), bind); 114 return -EEXIST; 115 } 116 } 117 m = to_mirred(pc); 118 119 spin_lock_bh(&m->tcf_lock); 120 m->tcf_action = parm->action; 121 m->tcfm_eaction = parm->eaction; 122 if (parm->ifindex) { 123 m->tcfm_ifindex = parm->ifindex; 124 if (ret != ACT_P_CREATED) 125 dev_put(m->tcfm_dev); 126 m->tcfm_dev = dev; 127 dev_hold(dev); 128 m->tcfm_ok_push = ok_push; 129 } 130 spin_unlock_bh(&m->tcf_lock); 131 if (ret == ACT_P_CREATED) 132 tcf_hash_insert(pc, &mirred_hash_info); 133 134 return ret; 135 } 136 137 static int tcf_mirred_cleanup(struct tc_action *a, int bind) 138 { 139 struct tcf_mirred *m = a->priv; 140 141 if (m) 142 return tcf_mirred_release(m, bind); 143 return 0; 144 } 145 146 static int tcf_mirred(struct sk_buff *skb, struct tc_action *a, 147 struct tcf_result *res) 148 { 149 struct tcf_mirred *m = a->priv; 150 struct net_device *dev; 151 struct sk_buff *skb2 = NULL; 152 u32 at = G_TC_AT(skb->tc_verd); 153 154 spin_lock(&m->tcf_lock); 155 156 dev = m->tcfm_dev; 157 m->tcf_tm.lastuse = jiffies; 158 159 if (!(dev->flags&IFF_UP) ) { 160 if (net_ratelimit()) 161 printk("mirred to Houston: device %s is gone!\n", 162 dev->name); 163 bad_mirred: 164 if (skb2 != NULL) 165 kfree_skb(skb2); 166 m->tcf_qstats.overlimits++; 167 m->tcf_bstats.bytes += skb->len; 168 m->tcf_bstats.packets++; 169 spin_unlock(&m->tcf_lock); 170 /* should we be asking for packet to be dropped? 171 * may make sense for redirect case only 172 */ 173 return TC_ACT_SHOT; 174 } 175 176 skb2 = skb_act_clone(skb, GFP_ATOMIC); 177 if (skb2 == NULL) 178 goto bad_mirred; 179 if (m->tcfm_eaction != TCA_EGRESS_MIRROR && 180 m->tcfm_eaction != TCA_EGRESS_REDIR) { 181 if (net_ratelimit()) 182 printk("tcf_mirred unknown action %d\n", 183 m->tcfm_eaction); 184 goto bad_mirred; 185 } 186 187 m->tcf_bstats.bytes += skb2->len; 188 m->tcf_bstats.packets++; 189 if (!(at & AT_EGRESS)) 190 if (m->tcfm_ok_push) 191 skb_push(skb2, skb2->dev->hard_header_len); 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->dev = dev; 198 skb2->iif = skb->dev->ifindex; 199 dev_queue_xmit(skb2); 200 spin_unlock(&m->tcf_lock); 201 return m->tcf_action; 202 } 203 204 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) 205 { 206 unsigned char *b = skb_tail_pointer(skb); 207 struct tcf_mirred *m = a->priv; 208 struct tc_mirred opt; 209 struct tcf_t t; 210 211 opt.index = m->tcf_index; 212 opt.action = m->tcf_action; 213 opt.refcnt = m->tcf_refcnt - ref; 214 opt.bindcnt = m->tcf_bindcnt - bind; 215 opt.eaction = m->tcfm_eaction; 216 opt.ifindex = m->tcfm_ifindex; 217 NLA_PUT(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt); 218 t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install); 219 t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse); 220 t.expires = jiffies_to_clock_t(m->tcf_tm.expires); 221 NLA_PUT(skb, TCA_MIRRED_TM, sizeof(t), &t); 222 return skb->len; 223 224 nla_put_failure: 225 nlmsg_trim(skb, b); 226 return -1; 227 } 228 229 static struct tc_action_ops act_mirred_ops = { 230 .kind = "mirred", 231 .hinfo = &mirred_hash_info, 232 .type = TCA_ACT_MIRRED, 233 .capab = TCA_CAP_NONE, 234 .owner = THIS_MODULE, 235 .act = tcf_mirred, 236 .dump = tcf_mirred_dump, 237 .cleanup = tcf_mirred_cleanup, 238 .lookup = tcf_hash_search, 239 .init = tcf_mirred_init, 240 .walk = tcf_generic_walker 241 }; 242 243 MODULE_AUTHOR("Jamal Hadi Salim(2002)"); 244 MODULE_DESCRIPTION("Device Mirror/redirect actions"); 245 MODULE_LICENSE("GPL"); 246 247 static int __init mirred_init_module(void) 248 { 249 printk("Mirror/redirect action on\n"); 250 return tcf_register_action(&act_mirred_ops); 251 } 252 253 static void __exit mirred_cleanup_module(void) 254 { 255 tcf_unregister_action(&act_mirred_ops); 256 } 257 258 module_init(mirred_init_module); 259 module_exit(mirred_cleanup_module); 260