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 connmark_net_id;
  34
  35 static int tcf_connmark(struct sk_buff *skb, const struct tc_action *a,
  36                         struct tcf_result *res)
  37 {
  38         const struct nf_conntrack_tuple_hash *thash;
  39         struct nf_conntrack_tuple tuple;
  40         enum ip_conntrack_info ctinfo;
  41         struct tcf_connmark_info *ca = a->priv;
  42         struct nf_conntrack_zone zone;
  43         struct nf_conn *c;
  44         int proto;
  45
  46         spin_lock(&ca->tcf_lock);
  47         ca->tcf_tm.lastuse = jiffies;
  48         bstats_update(&ca->tcf_bstats, skb);
  49
  50         if (skb->protocol == htons(ETH_P_IP)) {
  51                 if (skb->len < sizeof(struct iphdr))
  52                         goto out;
  53
  54                 proto = NFPROTO_IPV4;
  55         } else if (skb->protocol == htons(ETH_P_IPV6)) {
  56                 if (skb->len < sizeof(struct ipv6hdr))
  57                         goto out;
  58
  59                 proto = NFPROTO_IPV6;
  60         } else {
  61                 goto out;
  62         }
  63
  64         c = nf_ct_get(skb, &ctinfo);
  65         if (c) {
  66                 skb->mark = c->mark;
  67                 /* using overlimits stats to count how many packets marked */
  68                 ca->tcf_qstats.overlimits++;
  69                 goto out;
  70         }
  71
  72         if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
  73                                proto, ca->net, &tuple))
  74                 goto out;
  75
  76         zone.id = ca->zone;
  77         zone.dir = NF_CT_DEFAULT_ZONE_DIR;
  78
  79         thash = nf_conntrack_find_get(ca->net, &zone, &tuple);
  80         if (!thash)
  81                 goto out;
  82
  83         c = nf_ct_tuplehash_to_ctrack(thash);
  84         /* using overlimits stats to count how many packets marked */
  85         ca->tcf_qstats.overlimits++;
  86         skb->mark = c->mark;
  87         nf_ct_put(c);
  88
  89 out:
  90         spin_unlock(&ca->tcf_lock);
  91         return ca->tcf_action;
  92 }
  93
  94 static const struct nla_policy connmark_policy[TCA_CONNMARK_MAX + 1] = {
  95         [TCA_CONNMARK_PARMS] = { .len = sizeof(struct tc_connmark) },
  96 };
  97
  98 static int tcf_connmark_init(struct net *net, struct nlattr *nla,
  99                              struct nlattr *est, struct tc_action *a,
 100                              int ovr, int bind)
 101 {
 102         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 103         struct nlattr *tb[TCA_CONNMARK_MAX + 1];
 104         struct tcf_connmark_info *ci;
 105         struct tc_connmark *parm;
 106         int ret = 0;
 107
 108         if (!nla)
 109                 return -EINVAL;
 110
 111         ret = nla_parse_nested(tb, TCA_CONNMARK_MAX, nla, connmark_policy);
 112         if (ret < 0)
 113                 return ret;
 114
 115         parm = nla_data(tb[TCA_CONNMARK_PARMS]);
 116
 117         if (!tcf_hash_check(tn, parm->index, a, bind)) {
 118                 ret = tcf_hash_create(tn, parm->index, est, a,
 119                                       sizeof(*ci), bind, false);
 120                 if (ret)
 121                         return ret;
 122
 123                 ci = to_connmark(a);
 124                 ci->tcf_action = parm->action;
 125                 ci->net = net;
 126                 ci->zone = parm->zone;
 127
 128                 tcf_hash_insert(tn, a);
 129                 ret = ACT_P_CREATED;
 130         } else {
 131                 ci = to_connmark(a);
 132                 if (bind)
 133                         return 0;
 134                 tcf_hash_release(a, bind);
 135                 if (!ovr)
 136                         return -EEXIST;
 137                 /* replacing action and zone */
 138                 ci->tcf_action = parm->action;
 139                 ci->zone = parm->zone;
 140         }
 141
 142         return ret;
 143 }
 144
 145 static inline int tcf_connmark_dump(struct sk_buff *skb, struct tc_action *a,
 146                                     int bind, int ref)
 147 {
 148         unsigned char *b = skb_tail_pointer(skb);
 149         struct tcf_connmark_info *ci = a->priv;
 150
 151         struct tc_connmark opt = {
 152                 .index   = ci->tcf_index,
 153                 .refcnt  = ci->tcf_refcnt - ref,
 154                 .bindcnt = ci->tcf_bindcnt - bind,
 155                 .action  = ci->tcf_action,
 156                 .zone   = ci->zone,
 157         };
 158         struct tcf_t t;
 159
 160         if (nla_put(skb, TCA_CONNMARK_PARMS, sizeof(opt), &opt))
 161                 goto nla_put_failure;
 162
 163         t.install = jiffies_to_clock_t(jiffies - ci->tcf_tm.install);
 164         t.lastuse = jiffies_to_clock_t(jiffies - ci->tcf_tm.lastuse);
 165         t.expires = jiffies_to_clock_t(ci->tcf_tm.expires);
 166         if (nla_put_64bit(skb, TCA_CONNMARK_TM, sizeof(t), &t,
 167                           TCA_CONNMARK_PAD))
 168                 goto nla_put_failure;
 169
 170         return skb->len;
 171 nla_put_failure:
 172         nlmsg_trim(skb, b);
 173         return -1;
 174 }
 175
 176 static int tcf_connmark_walker(struct net *net, struct sk_buff *skb,
 177                                struct netlink_callback *cb, int type,
 178                                struct tc_action *a)
 179 {
 180         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 181
 182         return tcf_generic_walker(tn, skb, cb, type, a);
 183 }
 184
 185 static int tcf_connmark_search(struct net *net, struct tc_action *a, u32 index)
 186 {
 187         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 188
 189         return tcf_hash_search(tn, a, index);
 190 }
 191
 192 static struct tc_action_ops act_connmark_ops = {
 193         .kind           =       "connmark",
 194         .type           =       TCA_ACT_CONNMARK,
 195         .owner          =       THIS_MODULE,
 196         .act            =       tcf_connmark,
 197         .dump           =       tcf_connmark_dump,
 198         .init           =       tcf_connmark_init,
 199         .walk           =       tcf_connmark_walker,
 200         .lookup         =       tcf_connmark_search,
 201 };
 202
 203 static __net_init int connmark_init_net(struct net *net)
 204 {
 205         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 206
 207         return tc_action_net_init(tn, &act_connmark_ops, CONNMARK_TAB_MASK);
 208 }
 209
 210 static void __net_exit connmark_exit_net(struct net *net)
 211 {
 212         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 213
 214         tc_action_net_exit(tn);
 215 }
 216
 217 static struct pernet_operations connmark_net_ops = {
 218         .init = connmark_init_net,
 219         .exit = connmark_exit_net,
 220         .id   = &connmark_net_id,
 221         .size = sizeof(struct tc_action_net),
 222 };
 223
 224 static int __init connmark_init_module(void)
 225 {
 226         return tcf_register_action(&act_connmark_ops, &connmark_net_ops);
 227 }
 228
 229 static void __exit connmark_cleanup_module(void)
 230 {
 231         tcf_unregister_action(&act_connmark_ops, &connmark_net_ops);
 232 }
 233
 234 module_init(connmark_init_module);
 235 module_exit(connmark_cleanup_module);
 236 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
 237 MODULE_DESCRIPTION("Connection tracking mark restoring");
 238 MODULE_LICENSE("GPL");
 239