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 27static struct tcf_common *tcf_pedit_ht[PEDIT_TAB_MASK + 1]; 28static u32 pedit_idx_gen; 29static DEFINE_RWLOCK(pedit_lock); 30 31static struct tcf_hashinfo pedit_hash_info = { 32 .htab = tcf_pedit_ht, 33 .hmask = PEDIT_TAB_MASK, 34 .lock = &pedit_lock, 35}; 36 37static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = { 38 [TCA_PEDIT_PARMS] = { .len = sizeof(struct tc_pedit) }, 39}; 40 41static 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 109static 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 123static 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_cloned(skb)) { 131 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 132 return p->tcf_action; 133 } 134 } 135 136 off = skb_network_offset(skb); 137 138 spin_lock(&p->tcf_lock); 139 140 p->tcf_tm.lastuse = jiffies; 141 142 if (p->tcfp_nkeys > 0) { 143 struct tc_pedit_key *tkey = p->tcfp_keys; 144 145 for (i = p->tcfp_nkeys; i > 0; i--, tkey++) { 146 u32 *ptr, _data; 147 int offset = tkey->off; 148 149 if (tkey->offmask) { 150 char *d, _d; 151 152 d = skb_header_pointer(skb, off + tkey->at, 1, 153 &_d); 154 if (!d) 155 goto bad; 156 offset += (*d & tkey->offmask) >> tkey->shift; 157 } 158 159 if (offset % 4) { 160 pr_info("tc filter pedit" 161 " offset must be on 32 bit boundaries\n"); 162 goto bad; 163 } 164 if (offset > 0 && offset > skb->len) { 165 pr_info("tc filter pedit" 166 " offset %d cant exceed pkt length %d\n", 167 offset, skb->len); 168 goto bad; 169 } 170 171 ptr = skb_header_pointer(skb, off + offset, 4, &_data); 172 if (!ptr) 173 goto bad; 174 /* just do it, baby */ 175 *ptr = ((*ptr & tkey->mask) ^ tkey->val); 176 if (ptr == &_data) 177 skb_store_bits(skb, off + offset, ptr, 4); 178 munged++; 179 } 180 181 if (munged) 182 skb->tc_verd = SET_TC_MUNGED(skb->tc_verd); 183 goto done; 184 } else 185 WARN(1, "pedit BUG: index %d\n", p->tcf_index); 186 187bad: 188 p->tcf_qstats.overlimits++; 189done: 190 p->tcf_bstats.bytes += qdisc_pkt_len(skb); 191 p->tcf_bstats.packets++; 192 spin_unlock(&p->tcf_lock); 193 return p->tcf_action; 194} 195 196static 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 NLA_PUT(skb, TCA_PEDIT_PARMS, s, opt); 222 t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install); 223 t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse); 224 t.expires = jiffies_to_clock_t(p->tcf_tm.expires); 225 NLA_PUT(skb, TCA_PEDIT_TM, sizeof(t), &t); 226 kfree(opt); 227 return skb->len; 228 229nla_put_failure: 230 nlmsg_trim(skb, b); 231 kfree(opt); 232 return -1; 233} 234 235static struct tc_action_ops act_pedit_ops = { 236 .kind = "pedit", 237 .hinfo = &pedit_hash_info, 238 .type = TCA_ACT_PEDIT, 239 .capab = TCA_CAP_NONE, 240 .owner = THIS_MODULE, 241 .act = tcf_pedit, 242 .dump = tcf_pedit_dump, 243 .cleanup = tcf_pedit_cleanup, 244 .lookup = tcf_hash_search, 245 .init = tcf_pedit_init, 246 .walk = tcf_generic_walker 247}; 248 249MODULE_AUTHOR("Jamal Hadi Salim(2002-4)"); 250MODULE_DESCRIPTION("Generic Packet Editor actions"); 251MODULE_LICENSE("GPL"); 252 253static int __init pedit_init_module(void) 254{ 255 return tcf_register_action(&act_pedit_ops); 256} 257 258static void __exit pedit_cleanup_module(void) 259{ 260 tcf_unregister_action(&act_pedit_ops); 261} 262 263module_init(pedit_init_module); 264module_exit(pedit_cleanup_module); 265