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_act(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, bool rtnl_held,
 100                              struct netlink_ext_ack *extack)
 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                                NULL);
 113         if (ret < 0)
 114                 return ret;
 115
 116         if (!tb[TCA_CONNMARK_PARMS])
 117                 return -EINVAL;
 118
 119         parm = nla_data(tb[TCA_CONNMARK_PARMS]);
 120
 121         ret = tcf_idr_check_alloc(tn, &parm->index, a, bind);
 122         if (!ret) {
 123                 ret = tcf_idr_create(tn, parm->index, est, a,
 124                                      &act_connmark_ops, bind, false);
 125                 if (ret) {
 126                         tcf_idr_cleanup(tn, parm->index);
 127                         return ret;
 128                 }
 129
 130                 ci = to_connmark(*a);
 131                 ci->tcf_action = parm->action;
 132                 ci->net = net;
 133                 ci->zone = parm->zone;
 134
 135                 tcf_idr_insert(tn, *a);
 136                 ret = ACT_P_CREATED;
 137         } else if (ret > 0) {
 138                 ci = to_connmark(*a);
 139                 if (bind)
 140                         return 0;
 141                 if (!ovr) {
 142                         tcf_idr_release(*a, bind);
 143                         return -EEXIST;
 144                 }
 145                 /* replacing action and zone */
 146                 spin_lock_bh(&ci->tcf_lock);
 147                 ci->tcf_action = parm->action;
 148                 ci->zone = parm->zone;
 149                 spin_unlock_bh(&ci->tcf_lock);
 150                 ret = 0;
 151         }
 152
 153         return ret;
 154 }
 155
 156 static inline int tcf_connmark_dump(struct sk_buff *skb, struct tc_action *a,
 157                                     int bind, int ref)
 158 {
 159         unsigned char *b = skb_tail_pointer(skb);
 160         struct tcf_connmark_info *ci = to_connmark(a);
 161         struct tc_connmark opt = {
 162                 .index   = ci->tcf_index,
 163                 .refcnt  = refcount_read(&ci->tcf_refcnt) - ref,
 164                 .bindcnt = atomic_read(&ci->tcf_bindcnt) - bind,
 165         };
 166         struct tcf_t t;
 167
 168         spin_lock_bh(&ci->tcf_lock);
 169         opt.action = ci->tcf_action;
 170         opt.zone = ci->zone;
 171         if (nla_put(skb, TCA_CONNMARK_PARMS, sizeof(opt), &opt))
 172                 goto nla_put_failure;
 173
 174         tcf_tm_dump(&t, &ci->tcf_tm);
 175         if (nla_put_64bit(skb, TCA_CONNMARK_TM, sizeof(t), &t,
 176                           TCA_CONNMARK_PAD))
 177                 goto nla_put_failure;
 178         spin_unlock_bh(&ci->tcf_lock);
 179
 180         return skb->len;
 181
 182 nla_put_failure:
 183         spin_unlock_bh(&ci->tcf_lock);
 184         nlmsg_trim(skb, b);
 185         return -1;
 186 }
 187
 188 static int tcf_connmark_walker(struct net *net, struct sk_buff *skb,
 189                                struct netlink_callback *cb, int type,
 190                                const struct tc_action_ops *ops,
 191                                struct netlink_ext_ack *extack)
 192 {
 193         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 194
 195         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 196 }
 197
 198 static int tcf_connmark_search(struct net *net, struct tc_action **a, u32 index)
 199 {
 200         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 201
 202         return tcf_idr_search(tn, a, index);
 203 }
 204
 205 static struct tc_action_ops act_connmark_ops = {
 206         .kind           =       "connmark",
 207         .id             =       TCA_ID_CONNMARK,
 208         .owner          =       THIS_MODULE,
 209         .act            =       tcf_connmark_act,
 210         .dump           =       tcf_connmark_dump,
 211         .init           =       tcf_connmark_init,
 212         .walk           =       tcf_connmark_walker,
 213         .lookup         =       tcf_connmark_search,
 214         .size           =       sizeof(struct tcf_connmark_info),
 215 };
 216
 217 static __net_init int connmark_init_net(struct net *net)
 218 {
 219         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 220
 221         return tc_action_net_init(tn, &act_connmark_ops);
 222 }
 223
 224 static void __net_exit connmark_exit_net(struct list_head *net_list)
 225 {
 226         tc_action_net_exit(net_list, connmark_net_id);
 227 }
 228
 229 static struct pernet_operations connmark_net_ops = {
 230         .init = connmark_init_net,
 231         .exit_batch = connmark_exit_net,
 232         .id   = &connmark_net_id,
 233         .size = sizeof(struct tc_action_net),
 234 };
 235
 236 static int __init connmark_init_module(void)
 237 {
 238         return tcf_register_action(&act_connmark_ops, &connmark_net_ops);
 239 }
 240
 241 static void __exit connmark_cleanup_module(void)
 242 {
 243         tcf_unregister_action(&act_connmark_ops, &connmark_net_ops);
 244 }
 245
 246 module_init(connmark_init_module);
 247 module_exit(connmark_cleanup_module);
 248 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
 249 MODULE_DESCRIPTION("Connection tracking mark restoring");
 250 MODULE_LICENSE("GPL");