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 static unsigned int connmark_net_id;
  32 static struct tc_action_ops act_connmark_ops;
  33
  34 static int tcf_connmark(struct sk_buff *skb, const struct tc_action *a,
  35                         struct tcf_result *res)
  36 {
  37         const struct nf_conntrack_tuple_hash *thash;
  38         struct nf_conntrack_tuple tuple;
  39         enum ip_conntrack_info ctinfo;
  40         struct tcf_connmark_info *ca = to_connmark(a);
  41         struct nf_conntrack_zone zone;
  42         struct nf_conn *c;
  43         int proto;
  44
  45         spin_lock(&ca->tcf_lock);
  46         tcf_lastuse_update(&ca->tcf_tm);
  47         bstats_update(&ca->tcf_bstats, skb);
  48
  49         if (skb->protocol == htons(ETH_P_IP)) {
  50                 if (skb->len < sizeof(struct iphdr))
  51                         goto out;
  52
  53                 proto = NFPROTO_IPV4;
  54         } else if (skb->protocol == htons(ETH_P_IPV6)) {
  55                 if (skb->len < sizeof(struct ipv6hdr))
  56                         goto out;
  57
  58                 proto = NFPROTO_IPV6;
  59         } else {
  60                 goto out;
  61         }
  62
  63         c = nf_ct_get(skb, &ctinfo);
  64         if (c) {
  65                 skb->mark = c->mark;
  66                 /* using overlimits stats to count how many packets marked */
  67                 ca->tcf_qstats.overlimits++;
  68                 goto out;
  69         }
  70
  71         if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
  72                                proto, ca->net, &tuple))
  73                 goto out;
  74
  75         zone.id = ca->zone;
  76         zone.dir = NF_CT_DEFAULT_ZONE_DIR;
  77
  78         thash = nf_conntrack_find_get(ca->net, &zone, &tuple);
  79         if (!thash)
  80                 goto out;
  81
  82         c = nf_ct_tuplehash_to_ctrack(thash);
  83         /* using overlimits stats to count how many packets marked */
  84         ca->tcf_qstats.overlimits++;
  85         skb->mark = c->mark;
  86         nf_ct_put(c);
  87
  88 out:
  89         spin_unlock(&ca->tcf_lock);
  90         return ca->tcf_action;
  91 }
  92
  93 static const struct nla_policy connmark_policy[TCA_CONNMARK_MAX + 1] = {
  94         [TCA_CONNMARK_PARMS] = { .len = sizeof(struct tc_connmark) },
  95 };
  96
  97 static int tcf_connmark_init(struct net *net, struct nlattr *nla,
  98                              struct nlattr *est, struct tc_action **a,
  99                              int ovr, int bind)
 100 {
 101         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 102         struct nlattr *tb[TCA_CONNMARK_MAX + 1];
 103         struct tcf_connmark_info *ci;
 104         struct tc_connmark *parm;
 105         int ret = 0;
 106
 107         if (!nla)
 108                 return -EINVAL;
 109
 110         ret = nla_parse_nested(tb, TCA_CONNMARK_MAX, nla, connmark_policy,
 111                                NULL);
 112         if (ret < 0)
 113                 return ret;
 114
 115         if (!tb[TCA_CONNMARK_PARMS])
 116                 return -EINVAL;
 117
 118         parm = nla_data(tb[TCA_CONNMARK_PARMS]);
 119
 120         if (!tcf_idr_check(tn, parm->index, a, bind)) {
 121                 ret = tcf_idr_create(tn, parm->index, est, a,
 122                                      &act_connmark_ops, bind, false);
 123                 if (ret)
 124                         return ret;
 125
 126                 ci = to_connmark(*a);
 127                 ci->tcf_action = parm->action;
 128                 ci->net = net;
 129                 ci->zone = parm->zone;
 130
 131                 tcf_idr_insert(tn, *a);
 132                 ret = ACT_P_CREATED;
 133         } else {
 134                 ci = to_connmark(*a);
 135                 if (bind)
 136                         return 0;
 137                 tcf_idr_release(*a, bind);
 138                 if (!ovr)
 139                         return -EEXIST;
 140                 /* replacing action and zone */
 141                 ci->tcf_action = parm->action;
 142                 ci->zone = parm->zone;
 143         }
 144
 145         return ret;
 146 }
 147
 148 static inline int tcf_connmark_dump(struct sk_buff *skb, struct tc_action *a,
 149                                     int bind, int ref)
 150 {
 151         unsigned char *b = skb_tail_pointer(skb);
 152         struct tcf_connmark_info *ci = to_connmark(a);
 153
 154         struct tc_connmark opt = {
 155                 .index   = ci->tcf_index,
 156                 .refcnt  = ci->tcf_refcnt - ref,
 157                 .bindcnt = ci->tcf_bindcnt - bind,
 158                 .action  = ci->tcf_action,
 159                 .zone   = ci->zone,
 160         };
 161         struct tcf_t t;
 162
 163         if (nla_put(skb, TCA_CONNMARK_PARMS, sizeof(opt), &opt))
 164                 goto nla_put_failure;
 165
 166         tcf_tm_dump(&t, &ci->tcf_tm);
 167         if (nla_put_64bit(skb, TCA_CONNMARK_TM, sizeof(t), &t,
 168                           TCA_CONNMARK_PAD))
 169                 goto nla_put_failure;
 170
 171         return skb->len;
 172 nla_put_failure:
 173         nlmsg_trim(skb, b);
 174         return -1;
 175 }
 176
 177 static int tcf_connmark_walker(struct net *net, struct sk_buff *skb,
 178                                struct netlink_callback *cb, int type,
 179                                const struct tc_action_ops *ops)
 180 {
 181         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 182
 183         return tcf_generic_walker(tn, skb, cb, type, ops);
 184 }
 185
 186 static int tcf_connmark_search(struct net *net, struct tc_action **a, u32 index)
 187 {
 188         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 189
 190         return tcf_idr_search(tn, a, index);
 191 }
 192
 193 static struct tc_action_ops act_connmark_ops = {
 194         .kind           =       "connmark",
 195         .type           =       TCA_ACT_CONNMARK,
 196         .owner          =       THIS_MODULE,
 197         .act            =       tcf_connmark,
 198         .dump           =       tcf_connmark_dump,
 199         .init           =       tcf_connmark_init,
 200         .walk           =       tcf_connmark_walker,
 201         .lookup         =       tcf_connmark_search,
 202         .size           =       sizeof(struct tcf_connmark_info),
 203 };
 204
 205 static __net_init int connmark_init_net(struct net *net)
 206 {
 207         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 208
 209         return tc_action_net_init(tn, &act_connmark_ops);
 210 }
 211
 212 static void __net_exit connmark_exit_net(struct net *net)
 213 {
 214         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 215
 216         tc_action_net_exit(tn);
 217 }
 218
 219 static struct pernet_operations connmark_net_ops = {
 220         .init = connmark_init_net,
 221         .exit = connmark_exit_net,
 222         .id   = &connmark_net_id,
 223         .size = sizeof(struct tc_action_net),
 224 };
 225
 226 static int __init connmark_init_module(void)
 227 {
 228         return tcf_register_action(&act_connmark_ops, &connmark_net_ops);
 229 }
 230
 231 static void __exit connmark_cleanup_module(void)
 232 {
 233         tcf_unregister_action(&act_connmark_ops, &connmark_net_ops);
 234 }
 235
 236 module_init(connmark_init_module);
 237 module_exit(connmark_cleanup_module);
 238 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
 239 MODULE_DESCRIPTION("Connection tracking mark restoring");
 240 MODULE_LICENSE("GPL");
 241