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