1 /* 2 * net/sched/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 static struct tcf_common *tcf_pedit_ht[PEDIT_TAB_MASK + 1]; 28 static u32 pedit_idx_gen; 29 static DEFINE_RWLOCK(pedit_lock); 30 31 static struct tcf_hashinfo pedit_hash_info = { 32 .htab = tcf_pedit_ht, 33 .hmask = PEDIT_TAB_MASK, 34 .lock = &pedit_lock, 35 }; 36 37 static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = { 38 [TCA_PEDIT_PARMS] = { .len = sizeof(struct tc_pedit) }, 39 }; 40 41 static int tcf_pedit_init(struct nlattr *nla, struct nlattr *est, 42 struct tc_action *a, int ovr, int bind) 43 { 44 struct nlattr *tb[TCA_PEDIT_MAX + 1]; 45 struct tc_pedit *parm; 46 int ret = 0, err; 47 struct tcf_pedit *p; 48 struct tcf_common *pc; 49 struct tc_pedit_key *keys = NULL; 50 int ksize; 51 52 if (nla == NULL) 53 return -EINVAL; 54 55 err = nla_parse_nested(tb, TCA_PEDIT_MAX, nla, pedit_policy); 56 if (err < 0) 57 return err; 58 59 if (tb[TCA_PEDIT_PARMS] == NULL) 60 return -EINVAL; 61 parm = nla_data(tb[TCA_PEDIT_PARMS]); 62 ksize = parm->nkeys * sizeof(struct tc_pedit_key); 63 if (nla_len(tb[TCA_PEDIT_PARMS]) < sizeof(*parm) + ksize) 64 return -EINVAL; 65 66 pc = tcf_hash_check(parm->index, a, bind, &pedit_hash_info); 67 if (!pc) { 68 if (!parm->nkeys) 69 return -EINVAL; 70 pc = tcf_hash_create(parm->index, est, a, sizeof(*p), bind, 71 &pedit_idx_gen, &pedit_hash_info); 72 if (IS_ERR(pc)) 73 return PTR_ERR(pc); 74 p = to_pedit(pc); 75 keys = kmalloc(ksize, GFP_KERNEL); 76 if (keys == NULL) { 77 if (est) 78 gen_kill_estimator(&pc->tcfc_bstats, 79 &pc->tcfc_rate_est); 80 kfree_rcu(pc, tcfc_rcu); 81 return -ENOMEM; 82 } 83 ret = ACT_P_CREATED; 84 } else { 85 p = to_pedit(pc); 86 if (!ovr) { 87 tcf_hash_release(pc, bind, &pedit_hash_info); 88 return -EEXIST; 89 } 90 if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) { 91 keys = kmalloc(ksize, GFP_KERNEL); 92 if (keys == NULL) 93 return -ENOMEM; 94 } 95 } 96 97 spin_lock_bh(&p->tcf_lock); 98 p->tcfp_flags = parm->flags; 99 p->tcf_action = parm->action; 100 if (keys) { 101 kfree(p->tcfp_keys); 102 p->tcfp_keys = keys; 103 p->tcfp_nkeys = parm->nkeys; 104 } 105 memcpy(p->tcfp_keys, parm->keys, ksize); 106 spin_unlock_bh(&p->tcf_lock); 107 if (ret == ACT_P_CREATED) 108 tcf_hash_insert(pc, &pedit_hash_info); 109 return ret; 110 } 111 112 static int tcf_pedit_cleanup(struct tc_action *a, int bind) 113 { 114 struct tcf_pedit *p = a->priv; 115 116 if (p) { 117 struct tc_pedit_key *keys = p->tcfp_keys; 118 if (tcf_hash_release(&p->common, bind, &pedit_hash_info)) { 119 kfree(keys); 120 return 1; 121 } 122 } 123 return 0; 124 } 125 126 static int tcf_pedit(struct sk_buff *skb, const struct tc_action *a, 127 struct tcf_result *res) 128 { 129 struct tcf_pedit *p = a->priv; 130 int i, munged = 0; 131 unsigned int off; 132 133 if (skb_cloned(skb) && 134 pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) 135 return p->tcf_action; 136 137 off = skb_network_offset(skb); 138 139 spin_lock(&p->tcf_lock); 140 141 p->tcf_tm.lastuse = jiffies; 142 143 if (p->tcfp_nkeys > 0) { 144 struct tc_pedit_key *tkey = p->tcfp_keys; 145 146 for (i = p->tcfp_nkeys; i > 0; i--, tkey++) { 147 u32 *ptr, _data; 148 int offset = tkey->off; 149 150 if (tkey->offmask) { 151 char *d, _d; 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 if (offset > 0 && offset > skb->len) { 166 pr_info("tc filter pedit" 167 " offset %d can't exceed pkt length %d\n", 168 offset, skb->len); 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 munged++; 180 } 181 182 if (munged) 183 skb->tc_verd = SET_TC_MUNGED(skb->tc_verd); 184 goto done; 185 } else 186 WARN(1, "pedit BUG: index %d\n", p->tcf_index); 187 188 bad: 189 p->tcf_qstats.overlimits++; 190 done: 191 bstats_update(&p->tcf_bstats, skb); 192 spin_unlock(&p->tcf_lock); 193 return p->tcf_action; 194 } 195 196 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a, 197 int bind, int ref) 198 { 199 unsigned char *b = skb_tail_pointer(skb); 200 struct tcf_pedit *p = a->priv; 201 struct tc_pedit *opt; 202 struct tcf_t t; 203 int s; 204 205 s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key); 206 207 /* netlink spinlocks held above us - must use ATOMIC */ 208 opt = kzalloc(s, GFP_ATOMIC); 209 if (unlikely(!opt)) 210 return -ENOBUFS; 211 212 memcpy(opt->keys, p->tcfp_keys, 213 p->tcfp_nkeys * sizeof(struct tc_pedit_key)); 214 opt->index = p->tcf_index; 215 opt->nkeys = p->tcfp_nkeys; 216 opt->flags = p->tcfp_flags; 217 opt->action = p->tcf_action; 218 opt->refcnt = p->tcf_refcnt - ref; 219 opt->bindcnt = p->tcf_bindcnt - bind; 220 221 if (nla_put(skb, TCA_PEDIT_PARMS, s, opt)) 222 goto nla_put_failure; 223 t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install); 224 t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse); 225 t.expires = jiffies_to_clock_t(p->tcf_tm.expires); 226 if (nla_put(skb, TCA_PEDIT_TM, sizeof(t), &t)) 227 goto nla_put_failure; 228 kfree(opt); 229 return skb->len; 230 231 nla_put_failure: 232 nlmsg_trim(skb, b); 233 kfree(opt); 234 return -1; 235 } 236 237 static struct tc_action_ops act_pedit_ops = { 238 .kind = "pedit", 239 .hinfo = &pedit_hash_info, 240 .type = TCA_ACT_PEDIT, 241 .capab = TCA_CAP_NONE, 242 .owner = THIS_MODULE, 243 .act = tcf_pedit, 244 .dump = tcf_pedit_dump, 245 .cleanup = tcf_pedit_cleanup, 246 .lookup = tcf_hash_search, 247 .init = tcf_pedit_init, 248 .walk = tcf_generic_walker 249 }; 250 251 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)"); 252 MODULE_DESCRIPTION("Generic Packet Editor actions"); 253 MODULE_LICENSE("GPL"); 254 255 static int __init pedit_init_module(void) 256 { 257 return tcf_register_action(&act_pedit_ops); 258 } 259 260 static void __exit pedit_cleanup_module(void) 261 { 262 tcf_unregister_action(&act_pedit_ops); 263 } 264 265 module_init(pedit_init_module); 266 module_exit(pedit_cleanup_module); 267 268