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 <net/pkt_cls.h>
  25 #include <uapi/linux/tc_act/tc_connmark.h>
  26 #include <net/tc_act/tc_connmark.h>
  27
  28 #include <net/netfilter/nf_conntrack.h>
  29 #include <net/netfilter/nf_conntrack_core.h>
  30 #include <net/netfilter/nf_conntrack_zones.h>
  31
  32 static unsigned int connmark_net_id;
  33 static struct tc_action_ops act_connmark_ops;
  34
  35 static int tcf_connmark_act(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 = to_connmark(a);
  42         struct nf_conntrack_zone zone;
  43         struct nf_conn *c;
  44         int proto;
  45
  46         spin_lock(&ca->tcf_lock);
  47         tcf_lastuse_update(&ca->tcf_tm);
  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, bool rtnl_held,
 101                              struct tcf_proto *tp,
 102                              struct netlink_ext_ack *extack)
 103 {
 104         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 105         struct nlattr *tb[TCA_CONNMARK_MAX + 1];
 106         struct tcf_chain *goto_ch = NULL;
 107         struct tcf_connmark_info *ci;
 108         struct tc_connmark *parm;
 109         int ret = 0, err;
 110
 111         if (!nla)
 112                 return -EINVAL;
 113
 114         ret = nla_parse_nested(tb, TCA_CONNMARK_MAX, nla, connmark_policy,
 115                                NULL);
 116         if (ret < 0)
 117                 return ret;
 118
 119         if (!tb[TCA_CONNMARK_PARMS])
 120                 return -EINVAL;
 121
 122         parm = nla_data(tb[TCA_CONNMARK_PARMS]);
 123
 124         ret = tcf_idr_check_alloc(tn, &parm->index, a, bind);
 125         if (!ret) {
 126                 ret = tcf_idr_create(tn, parm->index, est, a,
 127                                      &act_connmark_ops, bind, false);
 128                 if (ret) {
 129                         tcf_idr_cleanup(tn, parm->index);
 130                         return ret;
 131                 }
 132
 133                 ci = to_connmark(*a);
 134                 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch,
 135                                                extack);
 136                 if (err < 0)
 137                         goto release_idr;
 138                 tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 139                 ci->net = net;
 140                 ci->zone = parm->zone;
 141
 142                 tcf_idr_insert(tn, *a);
 143                 ret = ACT_P_CREATED;
 144         } else if (ret > 0) {
 145                 ci = to_connmark(*a);
 146                 if (bind)
 147                         return 0;
 148                 if (!ovr) {
 149                         tcf_idr_release(*a, bind);
 150                         return -EEXIST;
 151                 }
 152                 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch,
 153                                                extack);
 154                 if (err < 0)
 155                         goto release_idr;
 156                 /* replacing action and zone */
 157                 spin_lock_bh(&ci->tcf_lock);
 158                 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 159                 ci->zone = parm->zone;
 160                 spin_unlock_bh(&ci->tcf_lock);
 161                 if (goto_ch)
 162                         tcf_chain_put_by_act(goto_ch);
 163                 ret = 0;
 164         }
 165
 166         return ret;
 167 release_idr:
 168         tcf_idr_release(*a, bind);
 169         return err;
 170 }
 171
 172 static inline int tcf_connmark_dump(struct sk_buff *skb, struct tc_action *a,
 173                                     int bind, int ref)
 174 {
 175         unsigned char *b = skb_tail_pointer(skb);
 176         struct tcf_connmark_info *ci = to_connmark(a);
 177         struct tc_connmark opt = {
 178                 .index   = ci->tcf_index,
 179                 .refcnt  = refcount_read(&ci->tcf_refcnt) - ref,
 180                 .bindcnt = atomic_read(&ci->tcf_bindcnt) - bind,
 181         };
 182         struct tcf_t t;
 183
 184         spin_lock_bh(&ci->tcf_lock);
 185         opt.action = ci->tcf_action;
 186         opt.zone = ci->zone;
 187         if (nla_put(skb, TCA_CONNMARK_PARMS, sizeof(opt), &opt))
 188                 goto nla_put_failure;
 189
 190         tcf_tm_dump(&t, &ci->tcf_tm);
 191         if (nla_put_64bit(skb, TCA_CONNMARK_TM, sizeof(t), &t,
 192                           TCA_CONNMARK_PAD))
 193                 goto nla_put_failure;
 194         spin_unlock_bh(&ci->tcf_lock);
 195
 196         return skb->len;
 197
 198 nla_put_failure:
 199         spin_unlock_bh(&ci->tcf_lock);
 200         nlmsg_trim(skb, b);
 201         return -1;
 202 }
 203
 204 static int tcf_connmark_walker(struct net *net, struct sk_buff *skb,
 205                                struct netlink_callback *cb, int type,
 206                                const struct tc_action_ops *ops,
 207                                struct netlink_ext_ack *extack)
 208 {
 209         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 210
 211         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 212 }
 213
 214 static int tcf_connmark_search(struct net *net, struct tc_action **a, u32 index)
 215 {
 216         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 217
 218         return tcf_idr_search(tn, a, index);
 219 }
 220
 221 static struct tc_action_ops act_connmark_ops = {
 222         .kind           =       "connmark",
 223         .id             =       TCA_ID_CONNMARK,
 224         .owner          =       THIS_MODULE,
 225         .act            =       tcf_connmark_act,
 226         .dump           =       tcf_connmark_dump,
 227         .init           =       tcf_connmark_init,
 228         .walk           =       tcf_connmark_walker,
 229         .lookup         =       tcf_connmark_search,
 230         .size           =       sizeof(struct tcf_connmark_info),
 231 };
 232
 233 static __net_init int connmark_init_net(struct net *net)
 234 {
 235         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 236
 237         return tc_action_net_init(tn, &act_connmark_ops);
 238 }
 239
 240 static void __net_exit connmark_exit_net(struct list_head *net_list)
 241 {
 242         tc_action_net_exit(net_list, connmark_net_id);
 243 }
 244
 245 static struct pernet_operations connmark_net_ops = {
 246         .init = connmark_init_net,
 247         .exit_batch = connmark_exit_net,
 248         .id   = &connmark_net_id,
 249         .size = sizeof(struct tc_action_net),
 250 };
 251
 252 static int __init connmark_init_module(void)
 253 {
 254         return tcf_register_action(&act_connmark_ops, &connmark_net_ops);
 255 }
 256
 257 static void __exit connmark_cleanup_module(void)
 258 {
 259         tcf_unregister_action(&act_connmark_ops, &connmark_net_ops);
 260 }
 261
 262 module_init(connmark_init_module);
 263 module_exit(connmark_cleanup_module);
 264 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
 265 MODULE_DESCRIPTION("Connection tracking mark restoring");
 266 MODULE_LICENSE("GPL");