net/sched/act_pedit.c

   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 <asm/uaccess.h>
  13 #include <asm/system.h>
  14 #include <asm/bitops.h>
  15 #include <linux/types.h>
  16 #include <linux/kernel.h>
  17 #include <linux/string.h>
  18 #include <linux/mm.h>
  19 #include <linux/socket.h>
  20 #include <linux/sockios.h>
  21 #include <linux/in.h>
  22 #include <linux/errno.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/netdevice.h>
  25 #include <linux/skbuff.h>
  26 #include <linux/rtnetlink.h>
  27 #include <linux/module.h>
  28 #include <linux/init.h>
  29 #include <linux/proc_fs.h>
  30 #include <net/sock.h>
  31 #include <net/pkt_sched.h>
  32 #include <linux/tc_act/tc_pedit.h>
  33 #include <net/tc_act/tc_pedit.h>
  34
  35 #define PEDIT_TAB_MASK  15
  36 static struct tcf_common *tcf_pedit_ht[PEDIT_TAB_MASK + 1];
  37 static u32 pedit_idx_gen;
  38 static DEFINE_RWLOCK(pedit_lock);
  39
  40 static struct tcf_hashinfo pedit_hash_info = {
  41         .htab   =       tcf_pedit_ht,
  42         .hmask  =       PEDIT_TAB_MASK,
  43         .lock   =       &pedit_lock,
  44 };
  45
  46 static int tcf_pedit_init(struct rtattr *rta, struct rtattr *est,
  47                           struct tc_action *a, int ovr, int bind)
  48 {
  49         struct rtattr *tb[TCA_PEDIT_MAX];
  50         struct tc_pedit *parm;
  51         int ret = 0;
  52         struct tcf_pedit *p;
  53         struct tcf_common *pc;
  54         struct tc_pedit_key *keys = NULL;
  55         int ksize;
  56
  57         if (rta == NULL || rtattr_parse_nested(tb, TCA_PEDIT_MAX, rta) < 0)
  58                 return -EINVAL;
  59
  60         if (tb[TCA_PEDIT_PARMS - 1] == NULL ||
  61             RTA_PAYLOAD(tb[TCA_PEDIT_PARMS-1]) < sizeof(*parm))
  62                 return -EINVAL;
  63         parm = RTA_DATA(tb[TCA_PEDIT_PARMS-1]);
  64         ksize = parm->nkeys * sizeof(struct tc_pedit_key);
  65         if (RTA_PAYLOAD(tb[TCA_PEDIT_PARMS-1]) < sizeof(*parm) + ksize)
  66                 return -EINVAL;
  67
  68         pc = tcf_hash_check(parm->index, a, bind, &pedit_hash_info);
  69         if (!pc) {
  70                 if (!parm->nkeys)
  71                         return -EINVAL;
  72                 pc = tcf_hash_create(parm->index, est, a, sizeof(*p), bind,
  73                                      &pedit_idx_gen, &pedit_hash_info);
  74                 if (unlikely(!pc))
  75                         return -ENOMEM;
  76                 p = to_pedit(pc);
  77                 keys = kmalloc(ksize, GFP_KERNEL);
  78                 if (keys == NULL) {
  79                         kfree(pc);
  80                         return -ENOMEM;
  81                 }
  82                 ret = ACT_P_CREATED;
  83         } else {
  84                 p = to_pedit(pc);
  85                 if (!ovr) {
  86                         tcf_hash_release(pc, bind, &pedit_hash_info);
  87                         return -EEXIST;
  88                 }
  89                 if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) {
  90                         keys = kmalloc(ksize, GFP_KERNEL);
  91                         if (keys == NULL)
  92                                 return -ENOMEM;
  93                 }
  94         }
  95
  96         spin_lock_bh(&p->tcf_lock);
  97         p->tcfp_flags = parm->flags;
  98         p->tcf_action = parm->action;
  99         if (keys) {
 100                 kfree(p->tcfp_keys);
 101                 p->tcfp_keys = keys;
 102                 p->tcfp_nkeys = parm->nkeys;
 103         }
 104         memcpy(p->tcfp_keys, parm->keys, ksize);
 105         spin_unlock_bh(&p->tcf_lock);
 106         if (ret == ACT_P_CREATED)
 107                 tcf_hash_insert(pc, &pedit_hash_info);
 108         return ret;
 109 }
 110
 111 static int tcf_pedit_cleanup(struct tc_action *a, int bind)
 112 {
 113         struct tcf_pedit *p = a->priv;
 114
 115         if (p) {
 116                 struct tc_pedit_key *keys = p->tcfp_keys;
 117                 if (tcf_hash_release(&p->common, bind, &pedit_hash_info)) {
 118                         kfree(keys);
 119                         return 1;
 120                 }
 121         }
 122         return 0;
 123 }
 124
 125 static int tcf_pedit(struct sk_buff *skb, struct tc_action *a,
 126                      struct tcf_result *res)
 127 {
 128         struct tcf_pedit *p = a->priv;
 129         int i, munged = 0;
 130         u8 *pptr;
 131
 132         if (!(skb->tc_verd & TC_OK2MUNGE)) {
 133                 /* should we set skb->cloned? */
 134                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
 135                         return p->tcf_action;
 136                 }
 137         }
 138
 139         pptr = skb->nh.raw;
 140
 141         spin_lock(&p->tcf_lock);
 142
 143         p->tcf_tm.lastuse = jiffies;
 144
 145         if (p->tcfp_nkeys > 0) {
 146                 struct tc_pedit_key *tkey = p->tcfp_keys;
 147
 148                 for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
 149                         u32 *ptr;
 150                         int offset = tkey->off;
 151
 152                         if (tkey->offmask) {
 153                                 if (skb->len > tkey->at) {
 154                                          char *j = pptr + tkey->at;
 155                                          offset += ((*j & tkey->offmask) >>
 156                                                    tkey->shift);
 157                                 } else {
 158                                         goto bad;
 159                                 }
 160                         }
 161
 162                         if (offset % 4) {
 163                                 printk("offset must be on 32 bit boundaries\n");
 164                                 goto bad;
 165                         }
 166                         if (skb->len < 0 ||
 167                             (offset > 0 && offset > skb->len)) {
 168                                 printk("offset %d cant exceed pkt length %d\n",
 169                                        offset, skb->len);
 170                                 goto bad;
 171                         }
 172
 173                         ptr = (u32 *)(pptr+offset);
 174                         /* just do it, baby */
 175                         *ptr = ((*ptr & tkey->mask) ^ tkey->val);
 176                         munged++;
 177                 }
 178
 179                 if (munged)
 180                         skb->tc_verd = SET_TC_MUNGED(skb->tc_verd);
 181                 goto done;
 182         } else {
 183                 printk("pedit BUG: index %d\n", p->tcf_index);
 184         }
 185
 186 bad:
 187         p->tcf_qstats.overlimits++;
 188 done:
 189         p->tcf_bstats.bytes += skb->len;
 190         p->tcf_bstats.packets++;
 191         spin_unlock(&p->tcf_lock);
 192         return p->tcf_action;
 193 }
 194
 195 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 196                           int bind, int ref)
 197 {
 198         unsigned char *b = skb->tail;
 199         struct tcf_pedit *p = a->priv;
 200         struct tc_pedit *opt;
 201         struct tcf_t t;
 202         int s;
 203
 204         s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key);
 205
 206         /* netlink spinlocks held above us - must use ATOMIC */
 207         opt = kzalloc(s, GFP_ATOMIC);
 208         if (unlikely(!opt))
 209                 return -ENOBUFS;
 210
 211         memcpy(opt->keys, p->tcfp_keys,
 212                p->tcfp_nkeys * sizeof(struct tc_pedit_key));
 213         opt->index = p->tcf_index;
 214         opt->nkeys = p->tcfp_nkeys;
 215         opt->flags = p->tcfp_flags;
 216         opt->action = p->tcf_action;
 217         opt->refcnt = p->tcf_refcnt - ref;
 218         opt->bindcnt = p->tcf_bindcnt - bind;
 219
 220         RTA_PUT(skb, TCA_PEDIT_PARMS, s, opt);
 221         t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
 222         t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
 223         t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
 224         RTA_PUT(skb, TCA_PEDIT_TM, sizeof(t), &t);
 225         kfree(opt);
 226         return skb->len;
 227
 228 rtattr_failure:
 229         skb_trim(skb, b - skb->data);
 230         kfree(opt);
 231         return -1;
 232 }
 233
 234 static struct tc_action_ops act_pedit_ops = {
 235         .kind           =       "pedit",
 236         .hinfo          =       &pedit_hash_info,
 237         .type           =       TCA_ACT_PEDIT,
 238         .capab          =       TCA_CAP_NONE,
 239         .owner          =       THIS_MODULE,
 240         .act            =       tcf_pedit,
 241         .dump           =       tcf_pedit_dump,
 242         .cleanup        =       tcf_pedit_cleanup,
 243         .lookup         =       tcf_hash_search,
 244         .init           =       tcf_pedit_init,
 245         .walk           =       tcf_generic_walker
 246 };
 247
 248 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 249 MODULE_DESCRIPTION("Generic Packet Editor actions");
 250 MODULE_LICENSE("GPL");
 251
 252 static int __init pedit_init_module(void)
 253 {
 254         return tcf_register_action(&act_pedit_ops);
 255 }
 256
 257 static void __exit pedit_cleanup_module(void)
 258 {
 259         tcf_unregister_action(&act_pedit_ops);
 260 }
 261
 262 module_init(pedit_init_module);
 263 module_exit(pedit_cleanup_module);
 264