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_conntrack_zone zone;
  41         struct nf_conn *c;
  42         int proto;
  43
  44         spin_lock(&ca->tcf_lock);
  45         ca->tcf_tm.lastuse = jiffies;
  46         bstats_update(&ca->tcf_bstats, skb);
  47
  48         if (skb->protocol == htons(ETH_P_IP)) {
  49                 if (skb->len < sizeof(struct iphdr))
  50                         goto out;
  51
  52                 proto = NFPROTO_IPV4;
  53         } else if (skb->protocol == htons(ETH_P_IPV6)) {
  54                 if (skb->len < sizeof(struct ipv6hdr))
  55                         goto out;
  56
  57                 proto = NFPROTO_IPV6;
  58         } else {
  59                 goto out;
  60         }
  61
  62         c = nf_ct_get(skb, &ctinfo);
  63         if (c) {
  64                 skb->mark = c->mark;
  65                 /* using overlimits stats to count how many packets marked */
  66                 ca->tcf_qstats.overlimits++;
  67                 goto out;
  68         }
  69
  70         if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
  71                                proto, &tuple))
  72                 goto out;
  73
  74         zone.id = ca->zone;
  75         zone.dir = NF_CT_DEFAULT_ZONE_DIR;
  76
  77         thash = nf_conntrack_find_get(dev_net(skb->dev), &zone, &tuple);
  78         if (!thash)
  79                 goto out;
  80
  81         c = nf_ct_tuplehash_to_ctrack(thash);
  82         /* using overlimits stats to count how many packets marked */
  83         ca->tcf_qstats.overlimits++;
  84         skb->mark = c->mark;
  85         nf_ct_put(c);
  86
  87 out:
  88         spin_unlock(&ca->tcf_lock);
  89         return ca->tcf_action;
  90 }
  91
  92 static const struct nla_policy connmark_policy[TCA_CONNMARK_MAX + 1] = {
  93         [TCA_CONNMARK_PARMS] = { .len = sizeof(struct tc_connmark) },
  94 };
  95
  96 static int tcf_connmark_init(struct net *net, struct nlattr *nla,
  97                              struct nlattr *est, struct tc_action *a,
  98                              int ovr, int bind)
  99 {
 100         struct nlattr *tb[TCA_CONNMARK_MAX + 1];
 101         struct tcf_connmark_info *ci;
 102         struct tc_connmark *parm;
 103         int ret = 0;
 104
 105         if (!nla)
 106                 return -EINVAL;
 107
 108         ret = nla_parse_nested(tb, TCA_CONNMARK_MAX, nla, connmark_policy);
 109         if (ret < 0)
 110                 return ret;
 111
 112         parm = nla_data(tb[TCA_CONNMARK_PARMS]);
 113
 114         if (!tcf_hash_check(parm->index, a, bind)) {
 115                 ret = tcf_hash_create(parm->index, est, a, sizeof(*ci),
 116                                       bind, false);
 117                 if (ret)
 118                         return ret;
 119
 120                 ci = to_connmark(a);
 121                 ci->tcf_action = parm->action;
 122                 ci->zone = parm->zone;
 123
 124                 tcf_hash_insert(a);
 125                 ret = ACT_P_CREATED;
 126         } else {
 127                 ci = to_connmark(a);
 128                 if (bind)
 129                         return 0;
 130                 tcf_hash_release(a, bind);
 131                 if (!ovr)
 132                         return -EEXIST;
 133                 /* replacing action and zone */
 134                 ci->tcf_action = parm->action;
 135                 ci->zone = parm->zone;
 136         }
 137
 138         return ret;
 139 }
 140
 141 static inline int tcf_connmark_dump(struct sk_buff *skb, struct tc_action *a,
 142                                     int bind, int ref)
 143 {
 144         unsigned char *b = skb_tail_pointer(skb);
 145         struct tcf_connmark_info *ci = a->priv;
 146
 147         struct tc_connmark opt = {
 148                 .index   = ci->tcf_index,
 149                 .refcnt  = ci->tcf_refcnt - ref,
 150                 .bindcnt = ci->tcf_bindcnt - bind,
 151                 .action  = ci->tcf_action,
 152                 .zone   = ci->zone,
 153         };
 154         struct tcf_t t;
 155
 156         if (nla_put(skb, TCA_CONNMARK_PARMS, sizeof(opt), &opt))
 157                 goto nla_put_failure;
 158
 159         t.install = jiffies_to_clock_t(jiffies - ci->tcf_tm.install);
 160         t.lastuse = jiffies_to_clock_t(jiffies - ci->tcf_tm.lastuse);
 161         t.expires = jiffies_to_clock_t(ci->tcf_tm.expires);
 162         if (nla_put(skb, TCA_CONNMARK_TM, sizeof(t), &t))
 163                 goto nla_put_failure;
 164
 165         return skb->len;
 166 nla_put_failure:
 167         nlmsg_trim(skb, b);
 168         return -1;
 169 }
 170
 171 static struct tc_action_ops act_connmark_ops = {
 172         .kind           =       "connmark",
 173         .type           =       TCA_ACT_CONNMARK,
 174         .owner          =       THIS_MODULE,
 175         .act            =       tcf_connmark,
 176         .dump           =       tcf_connmark_dump,
 177         .init           =       tcf_connmark_init,
 178 };
 179
 180 static int __init connmark_init_module(void)
 181 {
 182         return tcf_register_action(&act_connmark_ops, CONNMARK_TAB_MASK);
 183 }
 184
 185 static void __exit connmark_cleanup_module(void)
 186 {
 187         tcf_unregister_action(&act_connmark_ops);
 188 }
 189
 190 module_init(connmark_init_module);
 191 module_exit(connmark_cleanup_module);
 192 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
 193 MODULE_DESCRIPTION("Connection tracking mark restoring");
 194 MODULE_LICENSE("GPL");
 195