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 unsigned int connmark_net_id;
  34 static struct tc_action_ops act_connmark_ops;
  35
  36 static int tcf_connmark(struct sk_buff *skb, const struct tc_action *a,
  37                         struct tcf_result *res)
  38 {
  39         const struct nf_conntrack_tuple_hash *thash;
  40         struct nf_conntrack_tuple tuple;
  41         enum ip_conntrack_info ctinfo;
  42         struct tcf_connmark_info *ca = to_connmark(a);
  43         struct nf_conntrack_zone zone;
  44         struct nf_conn *c;
  45         int proto;
  46
  47         spin_lock(&ca->tcf_lock);
  48         tcf_lastuse_update(&ca->tcf_tm);
  49         bstats_update(&ca->tcf_bstats, skb);
  50
  51         if (skb->protocol == htons(ETH_P_IP)) {
  52                 if (skb->len < sizeof(struct iphdr))
  53                         goto out;
  54
  55                 proto = NFPROTO_IPV4;
  56         } else if (skb->protocol == htons(ETH_P_IPV6)) {
  57                 if (skb->len < sizeof(struct ipv6hdr))
  58                         goto out;
  59
  60                 proto = NFPROTO_IPV6;
  61         } else {
  62                 goto out;
  63         }
  64
  65         c = nf_ct_get(skb, &ctinfo);
  66         if (c) {
  67                 skb->mark = c->mark;
  68                 /* using overlimits stats to count how many packets marked */
  69                 ca->tcf_qstats.overlimits++;
  70                 goto out;
  71         }
  72
  73         if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
  74                                proto, ca->net, &tuple))
  75                 goto out;
  76
  77         zone.id = ca->zone;
  78         zone.dir = NF_CT_DEFAULT_ZONE_DIR;
  79
  80         thash = nf_conntrack_find_get(ca->net, &zone, &tuple);
  81         if (!thash)
  82                 goto out;
  83
  84         c = nf_ct_tuplehash_to_ctrack(thash);
  85         /* using overlimits stats to count how many packets marked */
  86         ca->tcf_qstats.overlimits++;
  87         skb->mark = c->mark;
  88         nf_ct_put(c);
  89
  90 out:
  91         spin_unlock(&ca->tcf_lock);
  92         return ca->tcf_action;
  93 }
  94
  95 static const struct nla_policy connmark_policy[TCA_CONNMARK_MAX + 1] = {
  96         [TCA_CONNMARK_PARMS] = { .len = sizeof(struct tc_connmark) },
  97 };
  98
  99 static int tcf_connmark_init(struct net *net, struct nlattr *nla,
 100                              struct nlattr *est, struct tc_action **a,
 101                              int ovr, int bind)
 102 {
 103         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 104         struct nlattr *tb[TCA_CONNMARK_MAX + 1];
 105         struct tcf_connmark_info *ci;
 106         struct tc_connmark *parm;
 107         int ret = 0;
 108
 109         if (!nla)
 110                 return -EINVAL;
 111
 112         ret = nla_parse_nested(tb, TCA_CONNMARK_MAX, nla, connmark_policy);
 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         if (!tcf_hash_check(tn, parm->index, a, bind)) {
 122                 ret = tcf_hash_create(tn, parm->index, est, a,
 123                                       &act_connmark_ops, bind, false);
 124                 if (ret)
 125                         return ret;
 126
 127                 ci = to_connmark(*a);
 128                 ci->tcf_action = parm->action;
 129                 ci->net = net;
 130                 ci->zone = parm->zone;
 131
 132                 tcf_hash_insert(tn, *a);
 133                 ret = ACT_P_CREATED;
 134         } else {
 135                 ci = to_connmark(*a);
 136                 if (bind)
 137                         return 0;
 138                 tcf_hash_release(*a, bind);
 139                 if (!ovr)
 140                         return -EEXIST;
 141                 /* replacing action and zone */
 142                 ci->tcf_action = parm->action;
 143                 ci->zone = parm->zone;
 144         }
 145
 146         return ret;
 147 }
 148
 149 static inline int tcf_connmark_dump(struct sk_buff *skb, struct tc_action *a,
 150                                     int bind, int ref)
 151 {
 152         unsigned char *b = skb_tail_pointer(skb);
 153         struct tcf_connmark_info *ci = to_connmark(a);
 154
 155         struct tc_connmark opt = {
 156                 .index   = ci->tcf_index,
 157                 .refcnt  = ci->tcf_refcnt - ref,
 158                 .bindcnt = ci->tcf_bindcnt - bind,
 159                 .action  = ci->tcf_action,
 160                 .zone   = ci->zone,
 161         };
 162         struct tcf_t t;
 163
 164         if (nla_put(skb, TCA_CONNMARK_PARMS, sizeof(opt), &opt))
 165                 goto nla_put_failure;
 166
 167         tcf_tm_dump(&t, &ci->tcf_tm);
 168         if (nla_put_64bit(skb, TCA_CONNMARK_TM, sizeof(t), &t,
 169                           TCA_CONNMARK_PAD))
 170                 goto nla_put_failure;
 171
 172         return skb->len;
 173 nla_put_failure:
 174         nlmsg_trim(skb, b);
 175         return -1;
 176 }
 177
 178 static int tcf_connmark_walker(struct net *net, struct sk_buff *skb,
 179                                struct netlink_callback *cb, int type,
 180                                const struct tc_action_ops *ops)
 181 {
 182         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 183
 184         return tcf_generic_walker(tn, skb, cb, type, ops);
 185 }
 186
 187 static int tcf_connmark_search(struct net *net, struct tc_action **a, u32 index)
 188 {
 189         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 190
 191         return tcf_hash_search(tn, a, index);
 192 }
 193
 194 static struct tc_action_ops act_connmark_ops = {
 195         .kind           =       "connmark",
 196         .type           =       TCA_ACT_CONNMARK,
 197         .owner          =       THIS_MODULE,
 198         .act            =       tcf_connmark,
 199         .dump           =       tcf_connmark_dump,
 200         .init           =       tcf_connmark_init,
 201         .walk           =       tcf_connmark_walker,
 202         .lookup         =       tcf_connmark_search,
 203         .size           =       sizeof(struct tcf_connmark_info),
 204 };
 205
 206 static __net_init int connmark_init_net(struct net *net)
 207 {
 208         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 209
 210         return tc_action_net_init(tn, &act_connmark_ops, CONNMARK_TAB_MASK);
 211 }
 212
 213 static void __net_exit connmark_exit_net(struct net *net)
 214 {
 215         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 216
 217         tc_action_net_exit(tn);
 218 }
 219
 220 static struct pernet_operations connmark_net_ops = {
 221         .init = connmark_init_net,
 222         .exit = connmark_exit_net,
 223         .id   = &connmark_net_id,
 224         .size = sizeof(struct tc_action_net),
 225 };
 226
 227 static int __init connmark_init_module(void)
 228 {
 229         return tcf_register_action(&act_connmark_ops, &connmark_net_ops);
 230 }
 231
 232 static void __exit connmark_cleanup_module(void)
 233 {
 234         tcf_unregister_action(&act_connmark_ops, &connmark_net_ops);
 235 }
 236
 237 module_init(connmark_init_module);
 238 module_exit(connmark_cleanup_module);
 239 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
 240 MODULE_DESCRIPTION("Connection tracking mark restoring");
 241 MODULE_LICENSE("GPL");
 242