net/sched/act_connmark.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * net/sched/act_connmark.c  netfilter connmark retriever action
   4  * skb mark is over-written
   5  *
   6  * Copyright (c) 2011 Felix Fietkau <nbd@openwrt.org>
   7 */
   8
   9 #include <linux/module.h>
  10 #include <linux/init.h>
  11 #include <linux/kernel.h>
  12 #include <linux/skbuff.h>
  13 #include <linux/rtnetlink.h>
  14 #include <linux/pkt_cls.h>
  15 #include <linux/ip.h>
  16 #include <linux/ipv6.h>
  17 #include <net/netlink.h>
  18 #include <net/pkt_sched.h>
  19 #include <net/act_api.h>
  20 #include <net/pkt_cls.h>
  21 #include <uapi/linux/tc_act/tc_connmark.h>
  22 #include <net/tc_act/tc_connmark.h>
  23
  24 #include <net/netfilter/nf_conntrack.h>
  25 #include <net/netfilter/nf_conntrack_core.h>
  26 #include <net/netfilter/nf_conntrack_zones.h>
  27
  28 static unsigned int connmark_net_id;
  29 static struct tc_action_ops act_connmark_ops;
  30
  31 static int tcf_connmark_act(struct sk_buff *skb, const struct tc_action *a,
  32                             struct tcf_result *res)
  33 {
  34         const struct nf_conntrack_tuple_hash *thash;
  35         struct nf_conntrack_tuple tuple;
  36         enum ip_conntrack_info ctinfo;
  37         struct tcf_connmark_info *ca = to_connmark(a);
  38         struct nf_conntrack_zone zone;
  39         struct nf_conn *c;
  40         int proto;
  41
  42         spin_lock(&ca->tcf_lock);
  43         tcf_lastuse_update(&ca->tcf_tm);
  44         bstats_update(&ca->tcf_bstats, skb);
  45
  46         switch (skb_protocol(skb, true)) {
  47         case htons(ETH_P_IP):
  48                 if (skb->len < sizeof(struct iphdr))
  49                         goto out;
  50
  51                 proto = NFPROTO_IPV4;
  52                 break;
  53         case htons(ETH_P_IPV6):
  54                 if (skb->len < sizeof(struct ipv6hdr))
  55                         goto out;
  56
  57                 proto = NFPROTO_IPV6;
  58                 break;
  59         default:
  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 tcf_proto *tp, u32 flags,
 101                              struct netlink_ext_ack *extack)
 102 {
 103         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 104         struct nlattr *tb[TCA_CONNMARK_MAX + 1];
 105         struct tcf_chain *goto_ch = NULL;
 106         struct tcf_connmark_info *ci;
 107         struct tc_connmark *parm;
 108         int ret = 0, err;
 109         u32 index;
 110
 111         if (!nla)
 112                 return -EINVAL;
 113
 114         ret = nla_parse_nested_deprecated(tb, TCA_CONNMARK_MAX, nla,
 115                                           connmark_policy, 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         index = parm->index;
 124         ret = tcf_idr_check_alloc(tn, &index, a, bind);
 125         if (!ret) {
 126                 ret = tcf_idr_create(tn, index, est, a,
 127                                      &act_connmark_ops, bind, false, 0);
 128                 if (ret) {
 129                         tcf_idr_cleanup(tn, 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                 ret = ACT_P_CREATED;
 143         } else if (ret > 0) {
 144                 ci = to_connmark(*a);
 145                 if (bind)
 146                         return 0;
 147                 if (!ovr) {
 148                         tcf_idr_release(*a, bind);
 149                         return -EEXIST;
 150                 }
 151                 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch,
 152                                                extack);
 153                 if (err < 0)
 154                         goto release_idr;
 155                 /* replacing action and zone */
 156                 spin_lock_bh(&ci->tcf_lock);
 157                 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 158                 ci->zone = parm->zone;
 159                 spin_unlock_bh(&ci->tcf_lock);
 160                 if (goto_ch)
 161                         tcf_chain_put_by_act(goto_ch);
 162                 ret = 0;
 163         }
 164
 165         return ret;
 166 release_idr:
 167         tcf_idr_release(*a, bind);
 168         return err;
 169 }
 170
 171 static inline int tcf_connmark_dump(struct sk_buff *skb, struct tc_action *a,
 172                                     int bind, int ref)
 173 {
 174         unsigned char *b = skb_tail_pointer(skb);
 175         struct tcf_connmark_info *ci = to_connmark(a);
 176         struct tc_connmark opt = {
 177                 .index   = ci->tcf_index,
 178                 .refcnt  = refcount_read(&ci->tcf_refcnt) - ref,
 179                 .bindcnt = atomic_read(&ci->tcf_bindcnt) - bind,
 180         };
 181         struct tcf_t t;
 182
 183         spin_lock_bh(&ci->tcf_lock);
 184         opt.action = ci->tcf_action;
 185         opt.zone = ci->zone;
 186         if (nla_put(skb, TCA_CONNMARK_PARMS, sizeof(opt), &opt))
 187                 goto nla_put_failure;
 188
 189         tcf_tm_dump(&t, &ci->tcf_tm);
 190         if (nla_put_64bit(skb, TCA_CONNMARK_TM, sizeof(t), &t,
 191                           TCA_CONNMARK_PAD))
 192                 goto nla_put_failure;
 193         spin_unlock_bh(&ci->tcf_lock);
 194
 195         return skb->len;
 196
 197 nla_put_failure:
 198         spin_unlock_bh(&ci->tcf_lock);
 199         nlmsg_trim(skb, b);
 200         return -1;
 201 }
 202
 203 static int tcf_connmark_walker(struct net *net, struct sk_buff *skb,
 204                                struct netlink_callback *cb, int type,
 205                                const struct tc_action_ops *ops,
 206                                struct netlink_ext_ack *extack)
 207 {
 208         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 209
 210         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 211 }
 212
 213 static int tcf_connmark_search(struct net *net, struct tc_action **a, u32 index)
 214 {
 215         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 216
 217         return tcf_idr_search(tn, a, index);
 218 }
 219
 220 static struct tc_action_ops act_connmark_ops = {
 221         .kind           =       "connmark",
 222         .id             =       TCA_ID_CONNMARK,
 223         .owner          =       THIS_MODULE,
 224         .act            =       tcf_connmark_act,
 225         .dump           =       tcf_connmark_dump,
 226         .init           =       tcf_connmark_init,
 227         .walk           =       tcf_connmark_walker,
 228         .lookup         =       tcf_connmark_search,
 229         .size           =       sizeof(struct tcf_connmark_info),
 230 };
 231
 232 static __net_init int connmark_init_net(struct net *net)
 233 {
 234         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 235
 236         return tc_action_net_init(net, tn, &act_connmark_ops);
 237 }
 238
 239 static void __net_exit connmark_exit_net(struct list_head *net_list)
 240 {
 241         tc_action_net_exit(net_list, connmark_net_id);
 242 }
 243
 244 static struct pernet_operations connmark_net_ops = {
 245         .init = connmark_init_net,
 246         .exit_batch = connmark_exit_net,
 247         .id   = &connmark_net_id,
 248         .size = sizeof(struct tc_action_net),
 249 };
 250
 251 static int __init connmark_init_module(void)
 252 {
 253         return tcf_register_action(&act_connmark_ops, &connmark_net_ops);
 254 }
 255
 256 static void __exit connmark_cleanup_module(void)
 257 {
 258         tcf_unregister_action(&act_connmark_ops, &connmark_net_ops);
 259 }
 260
 261 module_init(connmark_init_module);
 262 module_exit(connmark_cleanup_module);
 263 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
 264 MODULE_DESCRIPTION("Connection tracking mark restoring");
 265 MODULE_LICENSE("GPL");