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 int tcf_mirred_init(struct rtattr *rta, struct rtattr *est, 58 struct tc_action *a, int ovr, int bind) 59 { 60 struct rtattr *tb[TCA_MIRRED_MAX]; 61 struct tc_mirred *parm; 62 struct tcf_mirred *m; 63 struct tcf_common *pc; 64 struct net_device *dev = NULL; 65 int ret = 0; 66 int ok_push = 0; 67 68 if (rta == NULL || rtattr_parse_nested(tb, TCA_MIRRED_MAX, rta) < 0) 69 return -EINVAL; 70 71 if (tb[TCA_MIRRED_PARMS-1] == NULL || 72 RTA_PAYLOAD(tb[TCA_MIRRED_PARMS-1]) < sizeof(*parm)) 73 return -EINVAL; 74 parm = RTA_DATA(tb[TCA_MIRRED_PARMS-1]); 75 76 if (parm->ifindex) { 77 dev = __dev_get_by_index(&init_net, parm->ifindex); 78 if (dev == NULL) 79 return -ENODEV; 80 switch (dev->type) { 81 case ARPHRD_TUNNEL: 82 case ARPHRD_TUNNEL6: 83 case ARPHRD_SIT: 84 case ARPHRD_IPGRE: 85 case ARPHRD_VOID: 86 case ARPHRD_NONE: 87 ok_push = 0; 88 break; 89 default: 90 ok_push = 1; 91 break; 92 } 93 } 94 95 pc = tcf_hash_check(parm->index, a, bind, &mirred_hash_info); 96 if (!pc) { 97 if (!parm->ifindex) 98 return -EINVAL; 99 pc = tcf_hash_create(parm->index, est, a, sizeof(*m), bind, 100 &mirred_idx_gen, &mirred_hash_info); 101 if (unlikely(!pc)) 102 return -ENOMEM; 103 ret = ACT_P_CREATED; 104 } else { 105 if (!ovr) { 106 tcf_mirred_release(to_mirred(pc), bind); 107 return -EEXIST; 108 } 109 } 110 m = to_mirred(pc); 111 112 spin_lock_bh(&m->tcf_lock); 113 m->tcf_action = parm->action; 114 m->tcfm_eaction = parm->eaction; 115 if (parm->ifindex) { 116 m->tcfm_ifindex = parm->ifindex; 117 if (ret != ACT_P_CREATED) 118 dev_put(m->tcfm_dev); 119 m->tcfm_dev = dev; 120 dev_hold(dev); 121 m->tcfm_ok_push = ok_push; 122 } 123 spin_unlock_bh(&m->tcf_lock); 124 if (ret == ACT_P_CREATED) 125 tcf_hash_insert(pc, &mirred_hash_info); 126 127 return ret; 128 } 129 130 static int tcf_mirred_cleanup(struct tc_action *a, int bind) 131 { 132 struct tcf_mirred *m = a->priv; 133 134 if (m) 135 return tcf_mirred_release(m, bind); 136 return 0; 137 } 138 139 static int tcf_mirred(struct sk_buff *skb, struct tc_action *a, 140 struct tcf_result *res) 141 { 142 struct tcf_mirred *m = a->priv; 143 struct net_device *dev; 144 struct sk_buff *skb2 = NULL; 145 u32 at = G_TC_AT(skb->tc_verd); 146 147 spin_lock(&m->tcf_lock); 148 149 dev = m->tcfm_dev; 150 m->tcf_tm.lastuse = jiffies; 151 152 if (!(dev->flags&IFF_UP) ) { 153 if (net_ratelimit()) 154 printk("mirred to Houston: device %s is gone!\n", 155 dev->name); 156 bad_mirred: 157 if (skb2 != NULL) 158 kfree_skb(skb2); 159 m->tcf_qstats.overlimits++; 160 m->tcf_bstats.bytes += skb->len; 161 m->tcf_bstats.packets++; 162 spin_unlock(&m->tcf_lock); 163 /* should we be asking for packet to be dropped? 164 * may make sense for redirect case only 165 */ 166 return TC_ACT_SHOT; 167 } 168 169 skb2 = skb_clone(skb, GFP_ATOMIC); 170 if (skb2 == NULL) 171 goto bad_mirred; 172 if (m->tcfm_eaction != TCA_EGRESS_MIRROR && 173 m->tcfm_eaction != TCA_EGRESS_REDIR) { 174 if (net_ratelimit()) 175 printk("tcf_mirred unknown action %d\n", 176 m->tcfm_eaction); 177 goto bad_mirred; 178 } 179 180 m->tcf_bstats.bytes += skb2->len; 181 m->tcf_bstats.packets++; 182 if (!(at & AT_EGRESS)) 183 if (m->tcfm_ok_push) 184 skb_push(skb2, skb2->dev->hard_header_len); 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->dev = dev; 191 skb2->iif = skb->dev->ifindex; 192 dev_queue_xmit(skb2); 193 spin_unlock(&m->tcf_lock); 194 return m->tcf_action; 195 } 196 197 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) 198 { 199 unsigned char *b = skb_tail_pointer(skb); 200 struct tcf_mirred *m = a->priv; 201 struct tc_mirred opt; 202 struct tcf_t t; 203 204 opt.index = m->tcf_index; 205 opt.action = m->tcf_action; 206 opt.refcnt = m->tcf_refcnt - ref; 207 opt.bindcnt = m->tcf_bindcnt - bind; 208 opt.eaction = m->tcfm_eaction; 209 opt.ifindex = m->tcfm_ifindex; 210 RTA_PUT(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt); 211 t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install); 212 t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse); 213 t.expires = jiffies_to_clock_t(m->tcf_tm.expires); 214 RTA_PUT(skb, TCA_MIRRED_TM, sizeof(t), &t); 215 return skb->len; 216 217 rtattr_failure: 218 nlmsg_trim(skb, b); 219 return -1; 220 } 221 222 static struct tc_action_ops act_mirred_ops = { 223 .kind = "mirred", 224 .hinfo = &mirred_hash_info, 225 .type = TCA_ACT_MIRRED, 226 .capab = TCA_CAP_NONE, 227 .owner = THIS_MODULE, 228 .act = tcf_mirred, 229 .dump = tcf_mirred_dump, 230 .cleanup = tcf_mirred_cleanup, 231 .lookup = tcf_hash_search, 232 .init = tcf_mirred_init, 233 .walk = tcf_generic_walker 234 }; 235 236 MODULE_AUTHOR("Jamal Hadi Salim(2002)"); 237 MODULE_DESCRIPTION("Device Mirror/redirect actions"); 238 MODULE_LICENSE("GPL"); 239 240 static int __init mirred_init_module(void) 241 { 242 printk("Mirror/redirect action on\n"); 243 return tcf_register_action(&act_mirred_ops); 244 } 245 246 static void __exit mirred_cleanup_module(void) 247 { 248 tcf_unregister_action(&act_mirred_ops); 249 } 250 251 module_init(mirred_init_module); 252 module_exit(mirred_cleanup_module); 253