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   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/sched.h>
  18 #include <linux/string.h>
  19 #include <linux/mm.h>
  20 #include <linux/socket.h>
  21 #include <linux/sockios.h>
  22 #include <linux/in.h>
  23 #include <linux/errno.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/netdevice.h>
  26 #include <linux/skbuff.h>
  27 #include <linux/rtnetlink.h>
  28 #include <linux/module.h>
  29 #include <linux/init.h>
  30 #include <linux/proc_fs.h>
  31 #include <net/sock.h>
  32 #include <net/pkt_sched.h>
  33 #include <linux/tc_act/tc_pedit.h>
  34 #include <net/tc_act/tc_pedit.h>
  35
  36
  37 #define PEDIT_DEB 1
  38
  39 /* use generic hash table */
  40 #define MY_TAB_SIZE     16
  41 #define MY_TAB_MASK     15
  42 static u32 idx_gen;
  43 static struct tcf_pedit *tcf_pedit_ht[MY_TAB_SIZE];
  44 static DEFINE_RWLOCK(pedit_lock);
  45
  46 #define tcf_st          tcf_pedit
  47 #define tc_st           tc_pedit
  48 #define tcf_t_lock      pedit_lock
  49 #define tcf_ht          tcf_pedit_ht
  50
  51 #define CONFIG_NET_ACT_INIT 1
  52 #include <net/pkt_act.h>
  53
  54 static int
  55 tcf_pedit_init(struct rtattr *rta, struct rtattr *est, struct tc_action *a,
  56                int ovr, int bind)
  57 {
  58         struct rtattr *tb[TCA_PEDIT_MAX];
  59         struct tc_pedit *parm;
  60         int ret = 0;
  61         struct tcf_pedit *p;
  62         struct tc_pedit_key *keys = NULL;
  63         int ksize;
  64
  65         if (rta == NULL || rtattr_parse_nested(tb, TCA_PEDIT_MAX, rta) < 0)
  66                 return -EINVAL;
  67
  68         if (tb[TCA_PEDIT_PARMS - 1] == NULL ||
  69             RTA_PAYLOAD(tb[TCA_PEDIT_PARMS-1]) < sizeof(*parm))
  70                 return -EINVAL;
  71         parm = RTA_DATA(tb[TCA_PEDIT_PARMS-1]);
  72         ksize = parm->nkeys * sizeof(struct tc_pedit_key);
  73         if (RTA_PAYLOAD(tb[TCA_PEDIT_PARMS-1]) < sizeof(*parm) + ksize)
  74                 return -EINVAL;
  75
  76         p = tcf_hash_check(parm->index, a, ovr, bind);
  77         if (p == NULL) {
  78                 if (!parm->nkeys)
  79                         return -EINVAL;
  80                 p = tcf_hash_create(parm->index, est, a, sizeof(*p), ovr, bind);
  81                 if (p == NULL)
  82                         return -ENOMEM;
  83                 keys = kmalloc(ksize, GFP_KERNEL);
  84                 if (keys == NULL) {
  85                         kfree(p);
  86                         return -ENOMEM;
  87                 }
  88                 ret = ACT_P_CREATED;
  89         } else {
  90                 if (!ovr) {
  91                         tcf_hash_release(p, bind);
  92                         return -EEXIST;
  93                 }
  94                 if (p->nkeys && p->nkeys != parm->nkeys) {
  95                         keys = kmalloc(ksize, GFP_KERNEL);
  96                         if (keys == NULL)
  97                                 return -ENOMEM;
  98                 }
  99         }
 100
 101         spin_lock_bh(&p->lock);
 102         p->flags = parm->flags;
 103         p->action = parm->action;
 104         if (keys) {
 105                 kfree(p->keys);
 106                 p->keys = keys;
 107                 p->nkeys = parm->nkeys;
 108         }
 109         memcpy(p->keys, parm->keys, ksize);
 110         spin_unlock_bh(&p->lock);
 111         if (ret == ACT_P_CREATED)
 112                 tcf_hash_insert(p);
 113         return ret;
 114 }
 115
 116 static int
 117 tcf_pedit_cleanup(struct tc_action *a, int bind)
 118 {
 119         struct tcf_pedit *p = PRIV(a, pedit);
 120
 121         if (p != NULL) {
 122                 struct tc_pedit_key *keys = p->keys;
 123                 if (tcf_hash_release(p, bind)) {
 124                         kfree(keys);
 125                         return 1;
 126                 }
 127         }
 128         return 0;
 129 }
 130
 131 static int
 132 tcf_pedit(struct sk_buff *skb, struct tc_action *a, struct tcf_result *res)
 133 {
 134         struct tcf_pedit *p = PRIV(a, pedit);
 135         int i, munged = 0;
 136         u8 *pptr;
 137
 138         if (!(skb->tc_verd & TC_OK2MUNGE)) {
 139                 /* should we set skb->cloned? */
 140                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
 141                         return p->action;
 142                 }
 143         }
 144
 145         pptr = skb->nh.raw;
 146
 147         spin_lock(&p->lock);
 148
 149         p->tm.lastuse = jiffies;
 150
 151         if (p->nkeys > 0) {
 152                 struct tc_pedit_key *tkey = p->keys;
 153
 154                 for (i = p->nkeys; i > 0; i--, tkey++) {
 155                         u32 *ptr;
 156                         int offset = tkey->off;
 157
 158                         if (tkey->offmask) {
 159                                 if (skb->len > tkey->at) {
 160                                          char *j = pptr + tkey->at;
 161                                          offset += ((*j & tkey->offmask) >>
 162                                                    tkey->shift);
 163                                 } else {
 164                                         goto bad;
 165                                 }
 166                         }
 167
 168                         if (offset % 4) {
 169                                 printk("offset must be on 32 bit boundaries\n");
 170                                 goto bad;
 171                         }
 172                         if (skb->len < 0 || (offset > 0 && offset > skb->len)) {
 173                                 printk("offset %d cant exceed pkt length %d\n",
 174                                        offset, skb->len);
 175                                 goto bad;
 176                         }
 177
 178                         ptr = (u32 *)(pptr+offset);
 179                         /* just do it, baby */
 180                         *ptr = ((*ptr & tkey->mask) ^ tkey->val);
 181                         munged++;
 182                 }
 183
 184                 if (munged)
 185                         skb->tc_verd = SET_TC_MUNGED(skb->tc_verd);
 186                 goto done;
 187         } else {
 188                 printk("pedit BUG: index %d\n",p->index);
 189         }
 190
 191 bad:
 192         p->qstats.overlimits++;
 193 done:
 194         p->bstats.bytes += skb->len;
 195         p->bstats.packets++;
 196         spin_unlock(&p->lock);
 197         return p->action;
 198 }
 199
 200 static int
 201 tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,int bind, int ref)
 202 {
 203         unsigned char *b = skb->tail;
 204         struct tc_pedit *opt;
 205         struct tcf_pedit *p = PRIV(a, pedit);
 206         struct tcf_t t;
 207         int s;
 208
 209         s = sizeof(*opt) + p->nkeys * sizeof(struct tc_pedit_key);
 210
 211         /* netlink spinlocks held above us - must use ATOMIC */
 212         opt = kzalloc(s, GFP_ATOMIC);
 213         if (opt == NULL)
 214                 return -ENOBUFS;
 215
 216         memcpy(opt->keys, p->keys, p->nkeys * sizeof(struct tc_pedit_key));
 217         opt->index = p->index;
 218         opt->nkeys = p->nkeys;
 219         opt->flags = p->flags;
 220         opt->action = p->action;
 221         opt->refcnt = p->refcnt - ref;
 222         opt->bindcnt = p->bindcnt - bind;
 223
 224
 225 #ifdef PEDIT_DEB
 226         {
 227                 /* Debug - get rid of later */
 228                 int i;
 229                 struct tc_pedit_key *key = opt->keys;
 230
 231                 for (i=0; i<opt->nkeys; i++, key++) {
 232                         printk( "\n key #%d",i);
 233                         printk( "  at %d: val %08x mask %08x",
 234                         (unsigned int)key->off,
 235                         (unsigned int)key->val,
 236                         (unsigned int)key->mask);
 237                 }
 238         }
 239 #endif
 240
 241         RTA_PUT(skb, TCA_PEDIT_PARMS, s, opt);
 242         t.install = jiffies_to_clock_t(jiffies - p->tm.install);
 243         t.lastuse = jiffies_to_clock_t(jiffies - p->tm.lastuse);
 244         t.expires = jiffies_to_clock_t(p->tm.expires);
 245         RTA_PUT(skb, TCA_PEDIT_TM, sizeof(t), &t);
 246         kfree(opt);
 247         return skb->len;
 248
 249 rtattr_failure:
 250         skb_trim(skb, b - skb->data);
 251         kfree(opt);
 252         return -1;
 253 }
 254
 255 static
 256 struct tc_action_ops act_pedit_ops = {
 257         .kind           =       "pedit",
 258         .type           =       TCA_ACT_PEDIT,
 259         .capab          =       TCA_CAP_NONE,
 260         .owner          =       THIS_MODULE,
 261         .act            =       tcf_pedit,
 262         .dump           =       tcf_pedit_dump,
 263         .cleanup        =       tcf_pedit_cleanup,
 264         .lookup         =       tcf_hash_search,
 265         .init           =       tcf_pedit_init,
 266         .walk           =       tcf_generic_walker
 267 };
 268
 269 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 270 MODULE_DESCRIPTION("Generic Packet Editor actions");
 271 MODULE_LICENSE("GPL");
 272
 273 static int __init
 274 pedit_init_module(void)
 275 {
 276         return tcf_register_action(&act_pedit_ops);
 277 }
 278
 279 static void __exit
 280 pedit_cleanup_module(void)
 281 {
 282         tcf_unregister_action(&act_pedit_ops);
 283 }
 284
 285 module_init(pedit_init_module);
 286 module_exit(pedit_cleanup_module);
 287