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/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 *skb, struct tc_action *a, struct tcf_result *res)
 134 {
 135         struct tcf_pedit *p = PRIV(a, pedit);
 136         int i, munged = 0;
 137         u8 *pptr;
 138
 139         if (!(skb->tc_verd & TC_OK2MUNGE)) {
 140                 /* should we set skb->cloned? */
 141                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
 142                         return p->action;
 143                 }
 144         }
 145
 146         pptr = skb->nh.raw;
 147
 148         spin_lock(&p->lock);
 149
 150         p->tm.lastuse = jiffies;
 151
 152         if (p->nkeys > 0) {
 153                 struct tc_pedit_key *tkey = p->keys;
 154
 155                 for (i = p->nkeys; i > 0; i--, tkey++) {
 156                         u32 *ptr;
 157                         int offset = tkey->off;
 158
 159                         if (tkey->offmask) {
 160                                 if (skb->len > tkey->at) {
 161                                          char *j = pptr + tkey->at;
 162                                          offset += ((*j & tkey->offmask) >>
 163                                                    tkey->shift);
 164                                 } else {
 165                                         goto bad;
 166                                 }
 167                         }
 168
 169                         if (offset % 4) {
 170                                 printk("offset must be on 32 bit boundaries\n");
 171                                 goto bad;
 172                         }
 173                         if (skb->len < 0 || (offset > 0 && offset > skb->len)) {
 174                                 printk("offset %d cant exceed pkt length %d\n",
 175                                        offset, skb->len);
 176                                 goto bad;
 177                         }
 178
 179                         ptr = (u32 *)(pptr+offset);
 180                         /* just do it, baby */
 181                         *ptr = ((*ptr & tkey->mask) ^ tkey->val);
 182                         munged++;
 183                 }
 184
 185                 if (munged)
 186                         skb->tc_verd = SET_TC_MUNGED(skb->tc_verd);
 187                 goto done;
 188         } else {
 189                 printk("pedit BUG: index %d\n",p->index);
 190         }
 191
 192 bad:
 193         p->qstats.overlimits++;
 194 done:
 195         p->bstats.bytes += skb->len;
 196         p->bstats.packets++;
 197         spin_unlock(&p->lock);
 198         return p->action;
 199 }
 200
 201 static int
 202 tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,int bind, int ref)
 203 {
 204         unsigned char *b = skb->tail;
 205         struct tc_pedit *opt;
 206         struct tcf_pedit *p = PRIV(a, pedit);
 207         struct tcf_t t;
 208         int s;
 209
 210         s = sizeof(*opt) + p->nkeys * sizeof(struct tc_pedit_key);
 211
 212         /* netlink spinlocks held above us - must use ATOMIC */
 213         opt = kmalloc(s, GFP_ATOMIC);
 214         if (opt == NULL)
 215                 return -ENOBUFS;
 216         memset(opt, 0, s);
 217
 218         memcpy(opt->keys, p->keys, p->nkeys * sizeof(struct tc_pedit_key));
 219         opt->index = p->index;
 220         opt->nkeys = p->nkeys;
 221         opt->flags = p->flags;
 222         opt->action = p->action;
 223         opt->refcnt = p->refcnt - ref;
 224         opt->bindcnt = p->bindcnt - bind;
 225
 226
 227 #ifdef PEDIT_DEB
 228         {
 229                 /* Debug - get rid of later */
 230                 int i;
 231                 struct tc_pedit_key *key = opt->keys;
 232
 233                 for (i=0; i<opt->nkeys; i++, key++) {
 234                         printk( "\n key #%d",i);
 235                         printk( "  at %d: val %08x mask %08x",
 236                         (unsigned int)key->off,
 237                         (unsigned int)key->val,
 238                         (unsigned int)key->mask);
 239                 }
 240         }
 241 #endif
 242
 243         RTA_PUT(skb, TCA_PEDIT_PARMS, s, opt);
 244         t.install = jiffies_to_clock_t(jiffies - p->tm.install);
 245         t.lastuse = jiffies_to_clock_t(jiffies - p->tm.lastuse);
 246         t.expires = jiffies_to_clock_t(p->tm.expires);
 247         RTA_PUT(skb, TCA_PEDIT_TM, sizeof(t), &t);
 248         kfree(opt);
 249         return skb->len;
 250
 251 rtattr_failure:
 252         skb_trim(skb, b - skb->data);
 253         kfree(opt);
 254         return -1;
 255 }
 256
 257 static
 258 struct tc_action_ops act_pedit_ops = {
 259         .kind           =       "pedit",
 260         .type           =       TCA_ACT_PEDIT,
 261         .capab          =       TCA_CAP_NONE,
 262         .owner          =       THIS_MODULE,
 263         .act            =       tcf_pedit,
 264         .dump           =       tcf_pedit_dump,
 265         .cleanup        =       tcf_pedit_cleanup,
 266         .lookup         =       tcf_hash_search,
 267         .init           =       tcf_pedit_init,
 268         .walk           =       tcf_generic_walker
 269 };
 270
 271 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 272 MODULE_DESCRIPTION("Generic Packet Editor actions");
 273 MODULE_LICENSE("GPL");
 274
 275 static int __init
 276 pedit_init_module(void)
 277 {
 278         return tcf_register_action(&act_pedit_ops);
 279 }
 280
 281 static void __exit
 282 pedit_cleanup_module(void)
 283 {
 284         tcf_unregister_action(&act_pedit_ops);
 285 }
 286
 287 module_init(pedit_init_module);
 288 module_exit(pedit_cleanup_module);
 289