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 kfree(pc); 78 return -ENOMEM; 79 } 80 ret = ACT_P_CREATED; 81 } else { 82 p = to_pedit(pc); 83 if (!ovr) { 84 tcf_hash_release(pc, bind, &pedit_hash_info); 85 return -EEXIST; 86 } 87 if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) { 88 keys = kmalloc(ksize, GFP_KERNEL); 89 if (keys == NULL) 90 return -ENOMEM; 91 } 92 } 93 94 spin_lock_bh(&p->tcf_lock); 95 p->tcfp_flags = parm->flags; 96 p->tcf_action = parm->action; 97 if (keys) { 98 kfree(p->tcfp_keys); 99 p->tcfp_keys = keys; 100 p->tcfp_nkeys = parm->nkeys; 101 } 102 memcpy(p->tcfp_keys, parm->keys, ksize); 103 spin_unlock_bh(&p->tcf_lock); 104 if (ret == ACT_P_CREATED) 105 tcf_hash_insert(pc, &pedit_hash_info); 106 return ret; 107 } 108 109 static int tcf_pedit_cleanup(struct tc_action *a, int bind) 110 { 111 struct tcf_pedit *p = a->priv; 112 113 if (p) { 114 struct tc_pedit_key *keys = p->tcfp_keys; 115 if (tcf_hash_release(&p->common, bind, &pedit_hash_info)) { 116 kfree(keys); 117 return 1; 118 } 119 } 120 return 0; 121 } 122 123 static int tcf_pedit(struct sk_buff *skb, struct tc_action *a, 124 struct tcf_result *res) 125 { 126 struct tcf_pedit *p = a->priv; 127 int i, munged = 0; 128 unsigned int off; 129 130 if (!(skb->tc_verd & TC_OK2MUNGE)) { 131 /* should we set skb->cloned? */ 132 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 133 return p->tcf_action; 134 } 135 } 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 cant 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 p->tcf_bstats.bytes += qdisc_pkt_len(skb); 192 p->tcf_bstats.packets++; 193 spin_unlock(&p->tcf_lock); 194 return p->tcf_action; 195 } 196 197 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a, 198 int bind, int ref) 199 { 200 unsigned char *b = skb_tail_pointer(skb); 201 struct tcf_pedit *p = a->priv; 202 struct tc_pedit *opt; 203 struct tcf_t t; 204 int s; 205 206 s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key); 207 208 /* netlink spinlocks held above us - must use ATOMIC */ 209 opt = kzalloc(s, GFP_ATOMIC); 210 if (unlikely(!opt)) 211 return -ENOBUFS; 212 213 memcpy(opt->keys, p->tcfp_keys, 214 p->tcfp_nkeys * sizeof(struct tc_pedit_key)); 215 opt->index = p->tcf_index; 216 opt->nkeys = p->tcfp_nkeys; 217 opt->flags = p->tcfp_flags; 218 opt->action = p->tcf_action; 219 opt->refcnt = p->tcf_refcnt - ref; 220 opt->bindcnt = p->tcf_bindcnt - bind; 221 222 NLA_PUT(skb, TCA_PEDIT_PARMS, s, opt); 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 NLA_PUT(skb, TCA_PEDIT_TM, sizeof(t), &t); 227 kfree(opt); 228 return skb->len; 229 230 nla_put_failure: 231 nlmsg_trim(skb, b); 232 kfree(opt); 233 return -1; 234 } 235 236 static struct tc_action_ops act_pedit_ops = { 237 .kind = "pedit", 238 .hinfo = &pedit_hash_info, 239 .type = TCA_ACT_PEDIT, 240 .capab = TCA_CAP_NONE, 241 .owner = THIS_MODULE, 242 .act = tcf_pedit, 243 .dump = tcf_pedit_dump, 244 .cleanup = tcf_pedit_cleanup, 245 .lookup = tcf_hash_search, 246 .init = tcf_pedit_init, 247 .walk = tcf_generic_walker 248 }; 249 250 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)"); 251 MODULE_DESCRIPTION("Generic Packet Editor actions"); 252 MODULE_LICENSE("GPL"); 253 254 static int __init pedit_init_module(void) 255 { 256 return tcf_register_action(&act_pedit_ops); 257 } 258 259 static void __exit pedit_cleanup_module(void) 260 { 261 tcf_unregister_action(&act_pedit_ops); 262 } 263 264 module_init(pedit_init_module); 265 module_exit(pedit_cleanup_module); 266 267