net/sched/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/config.h>
  16 #include <linux/types.h>
  17 #include <linux/kernel.h>
  18 #include <linux/sched.h>
  19 #include <linux/string.h>
  20 #include <linux/mm.h>
  21 #include <linux/socket.h>
  22 #include <linux/sockios.h>
  23 #include <linux/in.h>
  24 #include <linux/errno.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/netdevice.h>
  27 #include <linux/skbuff.h>
  28 #include <linux/rtnetlink.h>
  29 #include <linux/module.h>
  30 #include <linux/init.h>
  31 #include <linux/proc_fs.h>
  32 #include <net/sock.h>
  33 #include <net/pkt_sched.h>
  34 #include <linux/tc_act/tc_pedit.h>
  35 #include <net/tc_act/tc_pedit.h>
  36
  37
  38 #define PEDIT_DEB 1
  39
  40 /* use generic hash table */
  41 #define MY_TAB_SIZE     16
  42 #define MY_TAB_MASK     15
  43 static u32 idx_gen;
  44 static struct tcf_pedit *tcf_pedit_ht[MY_TAB_SIZE];
  45 static DEFINE_RWLOCK(pedit_lock);
  46
  47 #define tcf_st          tcf_pedit
  48 #define tc_st           tc_pedit
  49 #define tcf_t_lock      pedit_lock
  50 #define tcf_ht          tcf_pedit_ht
  51
  52 #define CONFIG_NET_ACT_INIT 1
  53 #include <net/pkt_act.h>
  54
  55 static int
  56 tcf_pedit_init(struct rtattr *rta, struct rtattr *est, struct tc_action *a,
  57                int ovr, int bind)
  58 {
  59         struct rtattr *tb[TCA_PEDIT_MAX];
  60         struct tc_pedit *parm;
  61         int ret = 0;
  62         struct tcf_pedit *p;
  63         struct tc_pedit_key *keys = NULL;
  64         int ksize;
  65
  66         if (rta == NULL || rtattr_parse_nested(tb, TCA_PEDIT_MAX, rta) < 0)
  67                 return -EINVAL;
  68
  69         if (tb[TCA_PEDIT_PARMS - 1] == NULL ||
  70             RTA_PAYLOAD(tb[TCA_PEDIT_PARMS-1]) < sizeof(*parm))
  71                 return -EINVAL;
  72         parm = RTA_DATA(tb[TCA_PEDIT_PARMS-1]);
  73         ksize = parm->nkeys * sizeof(struct tc_pedit_key);
  74         if (RTA_PAYLOAD(tb[TCA_PEDIT_PARMS-1]) < sizeof(*parm) + ksize)
  75                 return -EINVAL;
  76
  77         p = tcf_hash_check(parm->index, a, ovr, bind);
  78         if (p == NULL) {
  79                 if (!parm->nkeys)
  80                         return -EINVAL;
  81                 p = tcf_hash_create(parm->index, est, a, sizeof(*p), ovr, bind);
  82                 if (p == NULL)
  83                         return -ENOMEM;
  84                 keys = kmalloc(ksize, GFP_KERNEL);
  85                 if (keys == NULL) {
  86                         kfree(p);
  87                         return -ENOMEM;
  88                 }
  89                 ret = ACT_P_CREATED;
  90         } else {
  91                 if (!ovr) {
  92                         tcf_hash_release(p, bind);
  93                         return -EEXIST;
  94                 }
  95                 if (p->nkeys && p->nkeys != parm->nkeys) {
  96                         keys = kmalloc(ksize, GFP_KERNEL);
  97                         if (keys == NULL)
  98                                 return -ENOMEM;
  99                 }
 100         }
 101
 102         spin_lock_bh(&p->lock);
 103         p->flags = parm->flags;
 104         p->action = parm->action;
 105         if (keys) {
 106                 kfree(p->keys);
 107                 p->keys = keys;
 108                 p->nkeys = parm->nkeys;
 109         }
 110         memcpy(p->keys, parm->keys, ksize);
 111         spin_unlock_bh(&p->lock);
 112         if (ret == ACT_P_CREATED)
 113                 tcf_hash_insert(p);
 114         return ret;
 115 }
 116
 117 static int
 118 tcf_pedit_cleanup(struct tc_action *a, int bind)
 119 {
 120         struct tcf_pedit *p = PRIV(a, pedit);
 121
 122         if (p != NULL) {
 123                 struct tc_pedit_key *keys = p->keys;
 124                 if (tcf_hash_release(p, bind)) {
 125                         kfree(keys);
 126                         return 1;
 127                 }
 128         }
 129         return 0;
 130 }
 131
 132 static int
 133 tcf_pedit(struct sk_buff **pskb, struct tc_action *a)
 134 {
 135         struct tcf_pedit *p = PRIV(a, pedit);
 136         struct sk_buff *skb = *pskb;
 137         int i, munged = 0;
 138         u8 *pptr;
 139
 140         if (!(skb->tc_verd & TC_OK2MUNGE)) {
 141                 /* should we set skb->cloned? */
 142                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
 143                         return p->action;
 144                 }
 145         }
 146
 147         pptr = skb->nh.raw;
 148
 149         spin_lock(&p->lock);
 150
 151         p->tm.lastuse = jiffies;
 152
 153         if (p->nkeys > 0) {
 154                 struct tc_pedit_key *tkey = p->keys;
 155
 156                 for (i = p->nkeys; i > 0; i--, tkey++) {
 157                         u32 *ptr;
 158                         int offset = tkey->off;
 159
 160                         if (tkey->offmask) {
 161                                 if (skb->len > tkey->at) {
 162                                          char *j = pptr + tkey->at;
 163                                          offset += ((*j & tkey->offmask) >>
 164                                                    tkey->shift);
 165                                 } else {
 166                                         goto bad;
 167                                 }
 168                         }
 169
 170                         if (offset % 4) {
 171                                 printk("offset must be on 32 bit boundaries\n");
 172                                 goto bad;
 173                         }
 174                         if (skb->len < 0 || (offset > 0 && offset > skb->len)) {
 175                                 printk("offset %d cant exceed pkt length %d\n",
 176                                        offset, skb->len);
 177                                 goto bad;
 178                         }
 179
 180                         ptr = (u32 *)(pptr+offset);
 181                         /* just do it, baby */
 182                         *ptr = ((*ptr & tkey->mask) ^ tkey->val);
 183                         munged++;
 184                 }
 185
 186                 if (munged)
 187                         skb->tc_verd = SET_TC_MUNGED(skb->tc_verd);
 188                 goto done;
 189         } else {
 190                 printk("pedit BUG: index %d\n",p->index);
 191         }
 192
 193 bad:
 194         p->qstats.overlimits++;
 195 done:
 196         p->bstats.bytes += skb->len;
 197         p->bstats.packets++;
 198         spin_unlock(&p->lock);
 199         return p->action;
 200 }
 201
 202 static int
 203 tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,int bind, int ref)
 204 {
 205         unsigned char *b = skb->tail;
 206         struct tc_pedit *opt;
 207         struct tcf_pedit *p = PRIV(a, pedit);
 208         struct tcf_t t;
 209         int s;
 210
 211         s = sizeof(*opt) + p->nkeys * sizeof(struct tc_pedit_key);
 212
 213         /* netlink spinlocks held above us - must use ATOMIC */
 214         opt = kmalloc(s, GFP_ATOMIC);
 215         if (opt == NULL)
 216                 return -ENOBUFS;
 217         memset(opt, 0, s);
 218
 219         memcpy(opt->keys, p->keys, p->nkeys * sizeof(struct tc_pedit_key));
 220         opt->index = p->index;
 221         opt->nkeys = p->nkeys;
 222         opt->flags = p->flags;
 223         opt->action = p->action;
 224         opt->refcnt = p->refcnt - ref;
 225         opt->bindcnt = p->bindcnt - bind;
 226
 227
 228 #ifdef PEDIT_DEB
 229         {
 230                 /* Debug - get rid of later */
 231                 int i;
 232                 struct tc_pedit_key *key = opt->keys;
 233
 234                 for (i=0; i<opt->nkeys; i++, key++) {
 235                         printk( "\n key #%d",i);
 236                         printk( "  at %d: val %08x mask %08x",
 237                         (unsigned int)key->off,
 238                         (unsigned int)key->val,
 239                         (unsigned int)key->mask);
 240                 }
 241         }
 242 #endif
 243
 244         RTA_PUT(skb, TCA_PEDIT_PARMS, s, opt);
 245         t.install = jiffies_to_clock_t(jiffies - p->tm.install);
 246         t.lastuse = jiffies_to_clock_t(jiffies - p->tm.lastuse);
 247         t.expires = jiffies_to_clock_t(p->tm.expires);
 248         RTA_PUT(skb, TCA_PEDIT_TM, sizeof(t), &t);
 249         return skb->len;
 250
 251 rtattr_failure:
 252         skb_trim(skb, b - skb->data);
 253         return -1;
 254 }
 255
 256 static
 257 struct tc_action_ops act_pedit_ops = {
 258         .kind           =       "pedit",
 259         .type           =       TCA_ACT_PEDIT,
 260         .capab          =       TCA_CAP_NONE,
 261         .owner          =       THIS_MODULE,
 262         .act            =       tcf_pedit,
 263         .dump           =       tcf_pedit_dump,
 264         .cleanup        =       tcf_pedit_cleanup,
 265         .lookup         =       tcf_hash_search,
 266         .init           =       tcf_pedit_init,
 267         .walk           =       tcf_generic_walker
 268 };
 269
 270 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 271 MODULE_DESCRIPTION("Generic Packet Editor actions");
 272 MODULE_LICENSE("GPL");
 273
 274 static int __init
 275 pedit_init_module(void)
 276 {
 277         return tcf_register_action(&act_pedit_ops);
 278 }
 279
 280 static void __exit
 281 pedit_cleanup_module(void)
 282 {
 283         tcf_unregister_action(&act_pedit_ops);
 284 }
 285
 286 module_init(pedit_init_module);
 287 module_exit(pedit_cleanup_module);
 288