1 /* 2 * net/sched/act_pedit.c Generic packet editor 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 12 #include <linux/types.h> 13 #include <linux/kernel.h> 14 #include <linux/string.h> 15 #include <linux/errno.h> 16 #include <linux/skbuff.h> 17 #include <linux/rtnetlink.h> 18 #include <linux/module.h> 19 #include <linux/init.h> 20 #include <linux/slab.h> 21 #include <net/netlink.h> 22 #include <net/pkt_sched.h> 23 #include <linux/tc_act/tc_pedit.h> 24 #include <net/tc_act/tc_pedit.h> 25 26 #define PEDIT_TAB_MASK 15 27 28 static unsigned int pedit_net_id; 29 static struct tc_action_ops act_pedit_ops; 30 31 static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = { 32 [TCA_PEDIT_PARMS] = { .len = sizeof(struct tc_pedit) }, 33 }; 34 35 static int tcf_pedit_init(struct net *net, struct nlattr *nla, 36 struct nlattr *est, struct tc_action **a, 37 int ovr, int bind) 38 { 39 struct tc_action_net *tn = net_generic(net, pedit_net_id); 40 struct nlattr *tb[TCA_PEDIT_MAX + 1]; 41 struct tc_pedit *parm; 42 int ret = 0, err; 43 struct tcf_pedit *p; 44 struct tc_pedit_key *keys = NULL; 45 int ksize; 46 47 if (nla == NULL) 48 return -EINVAL; 49 50 err = nla_parse_nested(tb, TCA_PEDIT_MAX, nla, pedit_policy); 51 if (err < 0) 52 return err; 53 54 if (tb[TCA_PEDIT_PARMS] == NULL) 55 return -EINVAL; 56 parm = nla_data(tb[TCA_PEDIT_PARMS]); 57 ksize = parm->nkeys * sizeof(struct tc_pedit_key); 58 if (nla_len(tb[TCA_PEDIT_PARMS]) < sizeof(*parm) + ksize) 59 return -EINVAL; 60 61 if (!tcf_hash_check(tn, parm->index, a, bind)) { 62 if (!parm->nkeys) 63 return -EINVAL; 64 ret = tcf_hash_create(tn, parm->index, est, a, 65 &act_pedit_ops, bind, false); 66 if (ret) 67 return ret; 68 p = to_pedit(*a); 69 keys = kmalloc(ksize, GFP_KERNEL); 70 if (keys == NULL) { 71 tcf_hash_cleanup(*a, est); 72 return -ENOMEM; 73 } 74 ret = ACT_P_CREATED; 75 } else { 76 if (bind) 77 return 0; 78 tcf_hash_release(*a, bind); 79 if (!ovr) 80 return -EEXIST; 81 p = to_pedit(*a); 82 if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) { 83 keys = kmalloc(ksize, GFP_KERNEL); 84 if (keys == NULL) 85 return -ENOMEM; 86 } 87 } 88 89 spin_lock_bh(&p->tcf_lock); 90 p->tcfp_flags = parm->flags; 91 p->tcf_action = parm->action; 92 if (keys) { 93 kfree(p->tcfp_keys); 94 p->tcfp_keys = keys; 95 p->tcfp_nkeys = parm->nkeys; 96 } 97 memcpy(p->tcfp_keys, parm->keys, ksize); 98 spin_unlock_bh(&p->tcf_lock); 99 if (ret == ACT_P_CREATED) 100 tcf_hash_insert(tn, *a); 101 return ret; 102 } 103 104 static void tcf_pedit_cleanup(struct tc_action *a, int bind) 105 { 106 struct tcf_pedit *p = to_pedit(a); 107 struct tc_pedit_key *keys = p->tcfp_keys; 108 kfree(keys); 109 } 110 111 static bool offset_valid(struct sk_buff *skb, int offset) 112 { 113 if (offset > 0 && offset > skb->len) 114 return false; 115 116 if (offset < 0 && -offset > skb_headroom(skb)) 117 return false; 118 119 return true; 120 } 121 122 static int tcf_pedit(struct sk_buff *skb, const struct tc_action *a, 123 struct tcf_result *res) 124 { 125 struct tcf_pedit *p = to_pedit(a); 126 int i; 127 unsigned int off; 128 129 if (skb_unclone(skb, GFP_ATOMIC)) 130 return p->tcf_action; 131 132 off = skb_network_offset(skb); 133 134 spin_lock(&p->tcf_lock); 135 136 tcf_lastuse_update(&p->tcf_tm); 137 138 if (p->tcfp_nkeys > 0) { 139 struct tc_pedit_key *tkey = p->tcfp_keys; 140 141 for (i = p->tcfp_nkeys; i > 0; i--, tkey++) { 142 u32 *ptr, _data; 143 int offset = tkey->off; 144 145 if (tkey->offmask) { 146 char *d, _d; 147 148 if (!offset_valid(skb, off + tkey->at)) { 149 pr_info("tc filter pedit 'at' offset %d out of bounds\n", 150 off + tkey->at); 151 goto bad; 152 } 153 d = skb_header_pointer(skb, off + tkey->at, 1, 154 &_d); 155 if (!d) 156 goto bad; 157 offset += (*d & tkey->offmask) >> tkey->shift; 158 } 159 160 if (offset % 4) { 161 pr_info("tc filter pedit" 162 " offset must be on 32 bit boundaries\n"); 163 goto bad; 164 } 165 166 if (!offset_valid(skb, off + offset)) { 167 pr_info("tc filter pedit offset %d out of bounds\n", 168 offset); 169 goto bad; 170 } 171 172 ptr = skb_header_pointer(skb, off + offset, 4, &_data); 173 if (!ptr) 174 goto bad; 175 /* just do it, baby */ 176 *ptr = ((*ptr & tkey->mask) ^ tkey->val); 177 if (ptr == &_data) 178 skb_store_bits(skb, off + offset, ptr, 4); 179 } 180 181 goto done; 182 } else 183 WARN(1, "pedit BUG: index %d\n", p->tcf_index); 184 185 bad: 186 p->tcf_qstats.overlimits++; 187 done: 188 bstats_update(&p->tcf_bstats, skb); 189 spin_unlock(&p->tcf_lock); 190 return p->tcf_action; 191 } 192 193 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a, 194 int bind, int ref) 195 { 196 unsigned char *b = skb_tail_pointer(skb); 197 struct tcf_pedit *p = to_pedit(a); 198 struct tc_pedit *opt; 199 struct tcf_t t; 200 int s; 201 202 s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key); 203 204 /* netlink spinlocks held above us - must use ATOMIC */ 205 opt = kzalloc(s, GFP_ATOMIC); 206 if (unlikely(!opt)) 207 return -ENOBUFS; 208 209 memcpy(opt->keys, p->tcfp_keys, 210 p->tcfp_nkeys * sizeof(struct tc_pedit_key)); 211 opt->index = p->tcf_index; 212 opt->nkeys = p->tcfp_nkeys; 213 opt->flags = p->tcfp_flags; 214 opt->action = p->tcf_action; 215 opt->refcnt = p->tcf_refcnt - ref; 216 opt->bindcnt = p->tcf_bindcnt - bind; 217 218 if (nla_put(skb, TCA_PEDIT_PARMS, s, opt)) 219 goto nla_put_failure; 220 221 tcf_tm_dump(&t, &p->tcf_tm); 222 if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD)) 223 goto nla_put_failure; 224 225 kfree(opt); 226 return skb->len; 227 228 nla_put_failure: 229 nlmsg_trim(skb, b); 230 kfree(opt); 231 return -1; 232 } 233 234 static int tcf_pedit_walker(struct net *net, struct sk_buff *skb, 235 struct netlink_callback *cb, int type, 236 const struct tc_action_ops *ops) 237 { 238 struct tc_action_net *tn = net_generic(net, pedit_net_id); 239 240 return tcf_generic_walker(tn, skb, cb, type, ops); 241 } 242 243 static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index) 244 { 245 struct tc_action_net *tn = net_generic(net, pedit_net_id); 246 247 return tcf_hash_search(tn, a, index); 248 } 249 250 static struct tc_action_ops act_pedit_ops = { 251 .kind = "pedit", 252 .type = TCA_ACT_PEDIT, 253 .owner = THIS_MODULE, 254 .act = tcf_pedit, 255 .dump = tcf_pedit_dump, 256 .cleanup = tcf_pedit_cleanup, 257 .init = tcf_pedit_init, 258 .walk = tcf_pedit_walker, 259 .lookup = tcf_pedit_search, 260 .size = sizeof(struct tcf_pedit), 261 }; 262 263 static __net_init int pedit_init_net(struct net *net) 264 { 265 struct tc_action_net *tn = net_generic(net, pedit_net_id); 266 267 return tc_action_net_init(tn, &act_pedit_ops, PEDIT_TAB_MASK); 268 } 269 270 static void __net_exit pedit_exit_net(struct net *net) 271 { 272 struct tc_action_net *tn = net_generic(net, pedit_net_id); 273 274 tc_action_net_exit(tn); 275 } 276 277 static struct pernet_operations pedit_net_ops = { 278 .init = pedit_init_net, 279 .exit = pedit_exit_net, 280 .id = &pedit_net_id, 281 .size = sizeof(struct tc_action_net), 282 }; 283 284 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)"); 285 MODULE_DESCRIPTION("Generic Packet Editor actions"); 286 MODULE_LICENSE("GPL"); 287 288 static int __init pedit_init_module(void) 289 { 290 return tcf_register_action(&act_pedit_ops, &pedit_net_ops); 291 } 292 293 static void __exit pedit_cleanup_module(void) 294 { 295 tcf_unregister_action(&act_pedit_ops, &pedit_net_ops); 296 } 297 298 module_init(pedit_init_module); 299 module_exit(pedit_cleanup_module); 300 301