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