| 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), |
| 61 | bind, false); |
| 62 | if (ret) |
| 63 | return ret; |
| 64 | p = to_pedit(a); |
| 65 | keys = kmalloc(ksize, GFP_KERNEL); |
| 66 | if (keys == NULL) { |
| 67 | tcf_hash_cleanup(a, est); |
| 68 | return -ENOMEM; |
| 69 | } |
| 70 | ret = ACT_P_CREATED; |
| 71 | } else { |
| 72 | if (bind) |
| 73 | return 0; |
| 74 | tcf_hash_release(a, bind); |
| 75 | if (!ovr) |
| 76 | return -EEXIST; |
| 77 | p = to_pedit(a); |
| 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 bool offset_valid(struct sk_buff *skb, int offset) |
| 108 | { |
| 109 | if (offset > 0 && offset > skb->len) |
| 110 | return false; |
| 111 | |
| 112 | if (offset < 0 && -offset > skb_headroom(skb)) |
| 113 | return false; |
| 114 | |
| 115 | return true; |
| 116 | } |
| 117 | |
| 118 | static int tcf_pedit(struct sk_buff *skb, const struct tc_action *a, |
| 119 | struct tcf_result *res) |
| 120 | { |
| 121 | struct tcf_pedit *p = a->priv; |
| 122 | int i; |
| 123 | unsigned int off; |
| 124 | |
| 125 | if (skb_unclone(skb, GFP_ATOMIC)) |
| 126 | return p->tcf_action; |
| 127 | |
| 128 | off = skb_network_offset(skb); |
| 129 | |
| 130 | spin_lock(&p->tcf_lock); |
| 131 | |
| 132 | p->tcf_tm.lastuse = jiffies; |
| 133 | |
| 134 | if (p->tcfp_nkeys > 0) { |
| 135 | struct tc_pedit_key *tkey = p->tcfp_keys; |
| 136 | |
| 137 | for (i = p->tcfp_nkeys; i > 0; i--, tkey++) { |
| 138 | u32 *ptr, _data; |
| 139 | int offset = tkey->off; |
| 140 | |
| 141 | if (tkey->offmask) { |
| 142 | char *d, _d; |
| 143 | |
| 144 | if (!offset_valid(skb, off + tkey->at)) { |
| 145 | pr_info("tc filter pedit 'at' offset %d out of bounds\n", |
| 146 | off + tkey->at); |
| 147 | goto bad; |
| 148 | } |
| 149 | d = skb_header_pointer(skb, off + tkey->at, 1, |
| 150 | &_d); |
| 151 | if (!d) |
| 152 | goto bad; |
| 153 | offset += (*d & tkey->offmask) >> tkey->shift; |
| 154 | } |
| 155 | |
| 156 | if (offset % 4) { |
| 157 | pr_info("tc filter pedit" |
| 158 | " offset must be on 32 bit boundaries\n"); |
| 159 | goto bad; |
| 160 | } |
| 161 | |
| 162 | if (!offset_valid(skb, off + offset)) { |
| 163 | pr_info("tc filter pedit offset %d out of bounds\n", |
| 164 | offset); |
| 165 | goto bad; |
| 166 | } |
| 167 | |
| 168 | ptr = skb_header_pointer(skb, off + offset, 4, &_data); |
| 169 | if (!ptr) |
| 170 | goto bad; |
| 171 | /* just do it, baby */ |
| 172 | *ptr = ((*ptr & tkey->mask) ^ tkey->val); |
| 173 | if (ptr == &_data) |
| 174 | skb_store_bits(skb, off + offset, ptr, 4); |
| 175 | } |
| 176 | |
| 177 | goto done; |
| 178 | } else |
| 179 | WARN(1, "pedit BUG: index %d\n", p->tcf_index); |
| 180 | |
| 181 | bad: |
| 182 | p->tcf_qstats.overlimits++; |
| 183 | done: |
| 184 | bstats_update(&p->tcf_bstats, skb); |
| 185 | spin_unlock(&p->tcf_lock); |
| 186 | return p->tcf_action; |
| 187 | } |
| 188 | |
| 189 | static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a, |
| 190 | int bind, int ref) |
| 191 | { |
| 192 | unsigned char *b = skb_tail_pointer(skb); |
| 193 | struct tcf_pedit *p = a->priv; |
| 194 | struct tc_pedit *opt; |
| 195 | struct tcf_t t; |
| 196 | int s; |
| 197 | |
| 198 | s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key); |
| 199 | |
| 200 | /* netlink spinlocks held above us - must use ATOMIC */ |
| 201 | opt = kzalloc(s, GFP_ATOMIC); |
| 202 | if (unlikely(!opt)) |
| 203 | return -ENOBUFS; |
| 204 | |
| 205 | memcpy(opt->keys, p->tcfp_keys, |
| 206 | p->tcfp_nkeys * sizeof(struct tc_pedit_key)); |
| 207 | opt->index = p->tcf_index; |
| 208 | opt->nkeys = p->tcfp_nkeys; |
| 209 | opt->flags = p->tcfp_flags; |
| 210 | opt->action = p->tcf_action; |
| 211 | opt->refcnt = p->tcf_refcnt - ref; |
| 212 | opt->bindcnt = p->tcf_bindcnt - bind; |
| 213 | |
| 214 | if (nla_put(skb, TCA_PEDIT_PARMS, s, opt)) |
| 215 | goto nla_put_failure; |
| 216 | t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install); |
| 217 | t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse); |
| 218 | t.expires = jiffies_to_clock_t(p->tcf_tm.expires); |
| 219 | if (nla_put(skb, TCA_PEDIT_TM, sizeof(t), &t)) |
| 220 | goto nla_put_failure; |
| 221 | kfree(opt); |
| 222 | return skb->len; |
| 223 | |
| 224 | nla_put_failure: |
| 225 | nlmsg_trim(skb, b); |
| 226 | kfree(opt); |
| 227 | return -1; |
| 228 | } |
| 229 | |
| 230 | static struct tc_action_ops act_pedit_ops = { |
| 231 | .kind = "pedit", |
| 232 | .type = TCA_ACT_PEDIT, |
| 233 | .owner = THIS_MODULE, |
| 234 | .act = tcf_pedit, |
| 235 | .dump = tcf_pedit_dump, |
| 236 | .cleanup = tcf_pedit_cleanup, |
| 237 | .init = tcf_pedit_init, |
| 238 | }; |
| 239 | |
| 240 | MODULE_AUTHOR("Jamal Hadi Salim(2002-4)"); |
| 241 | MODULE_DESCRIPTION("Generic Packet Editor actions"); |
| 242 | MODULE_LICENSE("GPL"); |
| 243 | |
| 244 | static int __init pedit_init_module(void) |
| 245 | { |
| 246 | return tcf_register_action(&act_pedit_ops, PEDIT_TAB_MASK); |
| 247 | } |
| 248 | |
| 249 | static void __exit pedit_cleanup_module(void) |
| 250 | { |
| 251 | tcf_unregister_action(&act_pedit_ops); |
| 252 | } |
| 253 | |
| 254 | module_init(pedit_init_module); |
| 255 | module_exit(pedit_cleanup_module); |
| 256 | |