net/sched/act_connmark.c

   1 /*
   2  * net/sched/act_connmark.c  netfilter connmark retriever action
   3  * skb mark is over-written
   4  *
   5  * Copyright (c) 2011 Felix Fietkau <nbd@openwrt.org>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11 */
  12
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/kernel.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/rtnetlink.h>
  18 #include <linux/pkt_cls.h>
  19 #include <linux/ip.h>
  20 #include <linux/ipv6.h>
  21 #include <net/netlink.h>
  22 #include <net/pkt_sched.h>
  23 #include <net/act_api.h>
  24 #include <uapi/linux/tc_act/tc_connmark.h>
  25 #include <net/tc_act/tc_connmark.h>
  26
  27 #include <net/netfilter/nf_conntrack.h>
  28 #include <net/netfilter/nf_conntrack_core.h>
  29 #include <net/netfilter/nf_conntrack_zones.h>
  30
  31 #define CONNMARK_TAB_MASK     3
  32
  33 static int tcf_connmark(struct sk_buff *skb, const struct tc_action *a,
  34                         struct tcf_result *res)
  35 {
  36         const struct nf_conntrack_tuple_hash *thash;
  37         struct nf_conntrack_tuple tuple;
  38         enum ip_conntrack_info ctinfo;
  39         struct tcf_connmark_info *ca = a->priv;
  40         struct nf_conn *c;
  41         int proto;
  42
  43         spin_lock(&ca->tcf_lock);
  44         ca->tcf_tm.lastuse = jiffies;
  45         bstats_update(&ca->tcf_bstats, skb);
  46
  47         if (skb->protocol == htons(ETH_P_IP)) {
  48                 if (skb->len < sizeof(struct iphdr))
  49                         goto out;
  50
  51                 proto = NFPROTO_IPV4;
  52         } else if (skb->protocol == htons(ETH_P_IPV6)) {
  53                 if (skb->len < sizeof(struct ipv6hdr))
  54                         goto out;
  55
  56                 proto = NFPROTO_IPV6;
  57         } else {
  58                 goto out;
  59         }
  60
  61         c = nf_ct_get(skb, &ctinfo);
  62         if (c) {
  63                 skb->mark = c->mark;
  64                 /* using overlimits stats to count how many packets marked */
  65                 ca->tcf_qstats.overlimits++;
  66                 nf_ct_put(c);
  67                 goto out;
  68         }
  69
  70         if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
  71                                proto, &tuple))
  72                 goto out;
  73
  74         thash = nf_conntrack_find_get(dev_net(skb->dev), ca->zone, &tuple);
  75         if (!thash)
  76                 goto out;
  77
  78         c = nf_ct_tuplehash_to_ctrack(thash);
  79         /* using overlimits stats to count how many packets marked */
  80         ca->tcf_qstats.overlimits++;
  81         skb->mark = c->mark;
  82         nf_ct_put(c);
  83
  84 out:
  85         skb->nfct = NULL;
  86         spin_unlock(&ca->tcf_lock);
  87         return ca->tcf_action;
  88 }
  89
  90 static const struct nla_policy connmark_policy[TCA_CONNMARK_MAX + 1] = {
  91         [TCA_CONNMARK_PARMS] = { .len = sizeof(struct tc_connmark) },
  92 };
  93
  94 static int tcf_connmark_init(struct net *net, struct nlattr *nla,
  95                              struct nlattr *est, struct tc_action *a,
  96                              int ovr, int bind)
  97 {
  98         struct nlattr *tb[TCA_CONNMARK_MAX + 1];
  99         struct tcf_connmark_info *ci;
 100         struct tc_connmark *parm;
 101         int ret = 0;
 102
 103         if (!nla)
 104                 return -EINVAL;
 105
 106         ret = nla_parse_nested(tb, TCA_CONNMARK_MAX, nla, connmark_policy);
 107         if (ret < 0)
 108                 return ret;
 109
 110         parm = nla_data(tb[TCA_CONNMARK_PARMS]);
 111
 112         if (!tcf_hash_check(parm->index, a, bind)) {
 113                 ret = tcf_hash_create(parm->index, est, a, sizeof(*ci), bind);
 114                 if (ret)
 115                         return ret;
 116
 117                 ci = to_connmark(a);
 118                 ci->tcf_action = parm->action;
 119                 ci->zone = parm->zone;
 120
 121                 tcf_hash_insert(a);
 122                 ret = ACT_P_CREATED;
 123         } else {
 124                 ci = to_connmark(a);
 125                 if (bind)
 126                         return 0;
 127                 tcf_hash_release(a, bind);
 128                 if (!ovr)
 129                         return -EEXIST;
 130                 /* replacing action and zone */
 131                 ci->tcf_action = parm->action;
 132                 ci->zone = parm->zone;
 133         }
 134
 135         return ret;
 136 }
 137
 138 static inline int tcf_connmark_dump(struct sk_buff *skb, struct tc_action *a,
 139                                     int bind, int ref)
 140 {
 141         unsigned char *b = skb_tail_pointer(skb);
 142         struct tcf_connmark_info *ci = a->priv;
 143
 144         struct tc_connmark opt = {
 145                 .index   = ci->tcf_index,
 146                 .refcnt  = ci->tcf_refcnt - ref,
 147                 .bindcnt = ci->tcf_bindcnt - bind,
 148                 .action  = ci->tcf_action,
 149                 .zone   = ci->zone,
 150         };
 151         struct tcf_t t;
 152
 153         if (nla_put(skb, TCA_CONNMARK_PARMS, sizeof(opt), &opt))
 154                 goto nla_put_failure;
 155
 156         t.install = jiffies_to_clock_t(jiffies - ci->tcf_tm.install);
 157         t.lastuse = jiffies_to_clock_t(jiffies - ci->tcf_tm.lastuse);
 158         t.expires = jiffies_to_clock_t(ci->tcf_tm.expires);
 159         if (nla_put(skb, TCA_CONNMARK_TM, sizeof(t), &t))
 160                 goto nla_put_failure;
 161
 162         return skb->len;
 163 nla_put_failure:
 164         nlmsg_trim(skb, b);
 165         return -1;
 166 }
 167
 168 static struct tc_action_ops act_connmark_ops = {
 169         .kind           =       "connmark",
 170         .type           =       TCA_ACT_CONNMARK,
 171         .owner          =       THIS_MODULE,
 172         .act            =       tcf_connmark,
 173         .dump           =       tcf_connmark_dump,
 174         .init           =       tcf_connmark_init,
 175 };
 176
 177 static int __init connmark_init_module(void)
 178 {
 179         return tcf_register_action(&act_connmark_ops, CONNMARK_TAB_MASK);
 180 }
 181
 182 static void __exit connmark_cleanup_module(void)
 183 {
 184         tcf_unregister_action(&act_connmark_ops);
 185 }
 186
 187 module_init(connmark_init_module);
 188 module_exit(connmark_cleanup_module);
 189 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
 190 MODULE_DESCRIPTION("Connection tracking mark restoring");
 191 MODULE_LICENSE("GPL");
 192