1 /* 2 * net/sched/act_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 <linux/slab.h> 21 #include <net/netlink.h> 22 #include <net/pkt_sched.h> 23 #include <linux/tc_act/tc_pedit.h> 24 #include <net/tc_act/tc_pedit.h> 25 26 #define PEDIT_TAB_MASK 15 27 28 static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = { 29 [TCA_PEDIT_PARMS] = { .len = sizeof(struct tc_pedit) }, 30 }; 31 32 static int tcf_pedit_init(struct net *net, struct nlattr *nla, 33 struct nlattr *est, struct tc_action *a, 34 int ovr, int bind) 35 { 36 struct nlattr *tb[TCA_PEDIT_MAX + 1]; 37 struct tc_pedit *parm; 38 int ret = 0, err; 39 struct tcf_pedit *p; 40 struct tc_pedit_key *keys = NULL; 41 int ksize; 42 43 if (nla == NULL) 44 return -EINVAL; 45 46 err = nla_parse_nested(tb, TCA_PEDIT_MAX, nla, pedit_policy); 47 if (err < 0) 48 return err; 49 50 if (tb[TCA_PEDIT_PARMS] == NULL) 51 return -EINVAL; 52 parm = nla_data(tb[TCA_PEDIT_PARMS]); 53 ksize = parm->nkeys * sizeof(struct tc_pedit_key); 54 if (nla_len(tb[TCA_PEDIT_PARMS]) < sizeof(*parm) + ksize) 55 return -EINVAL; 56 57 if (!tcf_hash_check(parm->index, a, bind)) { 58 if (!parm->nkeys) 59 return -EINVAL; 60 ret = tcf_hash_create(parm->index, est, a, sizeof(*p), bind); 61 if (ret) 62 return ret; 63 p = to_pedit(a); 64 keys = kmalloc(ksize, GFP_KERNEL); 65 if (keys == NULL) { 66 tcf_hash_cleanup(a, est); 67 return -ENOMEM; 68 } 69 ret = ACT_P_CREATED; 70 } else { 71 p = to_pedit(a); 72 tcf_hash_release(a, bind); 73 if (bind) 74 return 0; 75 if (!ovr) 76 return -EEXIST; 77 78 if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) { 79 keys = kmalloc(ksize, GFP_KERNEL); 80 if (keys == NULL) 81 return -ENOMEM; 82 } 83 } 84 85 spin_lock_bh(&p->tcf_lock); 86 p->tcfp_flags = parm->flags; 87 p->tcf_action = parm->action; 88 if (keys) { 89 kfree(p->tcfp_keys); 90 p->tcfp_keys = keys; 91 p->tcfp_nkeys = parm->nkeys; 92 } 93 memcpy(p->tcfp_keys, parm->keys, ksize); 94 spin_unlock_bh(&p->tcf_lock); 95 if (ret == ACT_P_CREATED) 96 tcf_hash_insert(a); 97 return ret; 98 } 99 100 static void tcf_pedit_cleanup(struct tc_action *a, int bind) 101 { 102 struct tcf_pedit *p = a->priv; 103 struct tc_pedit_key *keys = p->tcfp_keys; 104 kfree(keys); 105 } 106 107 static int tcf_pedit(struct sk_buff *skb, const struct tc_action *a, 108 struct tcf_result *res) 109 { 110 struct tcf_pedit *p = a->priv; 111 int i, munged = 0; 112 unsigned int off; 113 114 if (skb_unclone(skb, GFP_ATOMIC)) 115 return p->tcf_action; 116 117 off = skb_network_offset(skb); 118 119 spin_lock(&p->tcf_lock); 120 121 p->tcf_tm.lastuse = jiffies; 122 123 if (p->tcfp_nkeys > 0) { 124 struct tc_pedit_key *tkey = p->tcfp_keys; 125 126 for (i = p->tcfp_nkeys; i > 0; i--, tkey++) { 127 u32 *ptr, _data; 128 int offset = tkey->off; 129 130 if (tkey->offmask) { 131 char *d, _d; 132 133 d = skb_header_pointer(skb, off + tkey->at, 1, 134 &_d); 135 if (!d) 136 goto bad; 137 offset += (*d & tkey->offmask) >> tkey->shift; 138 } 139 140 if (offset % 4) { 141 pr_info("tc filter pedit" 142 " offset must be on 32 bit boundaries\n"); 143 goto bad; 144 } 145 if (offset > 0 && offset > skb->len) { 146 pr_info("tc filter pedit" 147 " offset %d can't exceed pkt length %d\n", 148 offset, skb->len); 149 goto bad; 150 } 151 152 ptr = skb_header_pointer(skb, off + offset, 4, &_data); 153 if (!ptr) 154 goto bad; 155 /* just do it, baby */ 156 *ptr = ((*ptr & tkey->mask) ^ tkey->val); 157 if (ptr == &_data) 158 skb_store_bits(skb, off + offset, ptr, 4); 159 munged++; 160 } 161 162 if (munged) 163 skb->tc_verd = SET_TC_MUNGED(skb->tc_verd); 164 goto done; 165 } else 166 WARN(1, "pedit BUG: index %d\n", p->tcf_index); 167 168 bad: 169 p->tcf_qstats.overlimits++; 170 done: 171 bstats_update(&p->tcf_bstats, skb); 172 spin_unlock(&p->tcf_lock); 173 return p->tcf_action; 174 } 175 176 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a, 177 int bind, int ref) 178 { 179 unsigned char *b = skb_tail_pointer(skb); 180 struct tcf_pedit *p = a->priv; 181 struct tc_pedit *opt; 182 struct tcf_t t; 183 int s; 184 185 s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key); 186 187 /* netlink spinlocks held above us - must use ATOMIC */ 188 opt = kzalloc(s, GFP_ATOMIC); 189 if (unlikely(!opt)) 190 return -ENOBUFS; 191 192 memcpy(opt->keys, p->tcfp_keys, 193 p->tcfp_nkeys * sizeof(struct tc_pedit_key)); 194 opt->index = p->tcf_index; 195 opt->nkeys = p->tcfp_nkeys; 196 opt->flags = p->tcfp_flags; 197 opt->action = p->tcf_action; 198 opt->refcnt = p->tcf_refcnt - ref; 199 opt->bindcnt = p->tcf_bindcnt - bind; 200 201 if (nla_put(skb, TCA_PEDIT_PARMS, s, opt)) 202 goto nla_put_failure; 203 t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install); 204 t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse); 205 t.expires = jiffies_to_clock_t(p->tcf_tm.expires); 206 if (nla_put(skb, TCA_PEDIT_TM, sizeof(t), &t)) 207 goto nla_put_failure; 208 kfree(opt); 209 return skb->len; 210 211 nla_put_failure: 212 nlmsg_trim(skb, b); 213 kfree(opt); 214 return -1; 215 } 216 217 static struct tc_action_ops act_pedit_ops = { 218 .kind = "pedit", 219 .type = TCA_ACT_PEDIT, 220 .owner = THIS_MODULE, 221 .act = tcf_pedit, 222 .dump = tcf_pedit_dump, 223 .cleanup = tcf_pedit_cleanup, 224 .init = tcf_pedit_init, 225 }; 226 227 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)"); 228 MODULE_DESCRIPTION("Generic Packet Editor actions"); 229 MODULE_LICENSE("GPL"); 230 231 static int __init pedit_init_module(void) 232 { 233 return tcf_register_action(&act_pedit_ops, PEDIT_TAB_MASK); 234 } 235 236 static void __exit pedit_cleanup_module(void) 237 { 238 tcf_unregister_action(&act_pedit_ops); 239 } 240 241 module_init(pedit_init_module); 242 module_exit(pedit_cleanup_module); 243 244