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 struct tc_action_ops act_connmark_ops;
  29
  30 static int tcf_connmark_act(struct sk_buff *skb, const struct tc_action *a,
  31                             struct tcf_result *res)
  32 {
  33         const struct nf_conntrack_tuple_hash *thash;
  34         struct nf_conntrack_tuple tuple;
  35         enum ip_conntrack_info ctinfo;
  36         struct tcf_connmark_info *ca = to_connmark(a);
  37         struct nf_conntrack_zone zone;
  38         struct nf_conn *c;
  39         int proto;
  40
  41         spin_lock(&ca->tcf_lock);
  42         tcf_lastuse_update(&ca->tcf_tm);
  43         bstats_update(&ca->tcf_bstats, skb);
  44
  45         switch (skb_protocol(skb, true)) {
  46         case htons(ETH_P_IP):
  47                 if (skb->len < sizeof(struct iphdr))
  48                         goto out;
  49
  50                 proto = NFPROTO_IPV4;
  51                 break;
  52         case htons(ETH_P_IPV6):
  53                 if (skb->len < sizeof(struct ipv6hdr))
  54                         goto out;
  55
  56                 proto = NFPROTO_IPV6;
  57                 break;
  58         default:
  59                 goto out;
  60         }
  61
  62         c = nf_ct_get(skb, &ctinfo);
  63         if (c) {
  64                 skb->mark = READ_ONCE(c->mark);
  65                 /* using overlimits stats to count how many packets marked */
  66                 ca->tcf_qstats.overlimits++;
  67                 goto out;
  68         }
  69
  70         if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
  71                                proto, ca->net, &tuple))
  72                 goto out;
  73
  74         zone.id = ca->zone;
  75         zone.dir = NF_CT_DEFAULT_ZONE_DIR;
  76
  77         thash = nf_conntrack_find_get(ca->net, &zone, &tuple);
  78         if (!thash)
  79                 goto out;
  80
  81         c = nf_ct_tuplehash_to_ctrack(thash);
  82         /* using overlimits stats to count how many packets marked */
  83         ca->tcf_qstats.overlimits++;
  84         skb->mark = READ_ONCE(c->mark);
  85         nf_ct_put(c);
  86
  87 out:
  88         spin_unlock(&ca->tcf_lock);
  89         return ca->tcf_action;
  90 }
  91
  92 static const struct nla_policy connmark_policy[TCA_CONNMARK_MAX + 1] = {
  93         [TCA_CONNMARK_PARMS] = { .len = sizeof(struct tc_connmark) },
  94 };
  95
  96 static int tcf_connmark_init(struct net *net, struct nlattr *nla,
  97                              struct nlattr *est, struct tc_action **a,
  98                              struct tcf_proto *tp, u32 flags,
  99                              struct netlink_ext_ack *extack)
 100 {
 101         struct tc_action_net *tn = net_generic(net, act_connmark_ops.net_id);
 102         struct nlattr *tb[TCA_CONNMARK_MAX + 1];
 103         bool bind = flags & TCA_ACT_FLAGS_BIND;
 104         struct tcf_chain *goto_ch = NULL;
 105         struct tcf_connmark_info *ci;
 106         struct tc_connmark *parm;
 107         int ret = 0, err;
 108         u32 index;
 109
 110         if (!nla)
 111                 return -EINVAL;
 112
 113         ret = nla_parse_nested_deprecated(tb, TCA_CONNMARK_MAX, nla,
 114                                           connmark_policy, NULL);
 115         if (ret < 0)
 116                 return ret;
 117
 118         if (!tb[TCA_CONNMARK_PARMS])
 119                 return -EINVAL;
 120
 121         parm = nla_data(tb[TCA_CONNMARK_PARMS]);
 122         index = parm->index;
 123         ret = tcf_idr_check_alloc(tn, &index, a, bind);
 124         if (!ret) {
 125                 ret = tcf_idr_create(tn, index, est, a,
 126                                      &act_connmark_ops, bind, false, flags);
 127                 if (ret) {
 128                         tcf_idr_cleanup(tn, index);
 129                         return ret;
 130                 }
 131
 132                 ci = to_connmark(*a);
 133                 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch,
 134                                                extack);
 135                 if (err < 0)
 136                         goto release_idr;
 137                 tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 138                 ci->net = net;
 139                 ci->zone = parm->zone;
 140
 141                 ret = ACT_P_CREATED;
 142         } else if (ret > 0) {
 143                 ci = to_connmark(*a);
 144                 if (bind)
 145                         return 0;
 146                 if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
 147                         tcf_idr_release(*a, bind);
 148                         return -EEXIST;
 149                 }
 150                 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch,
 151                                                extack);
 152                 if (err < 0)
 153                         goto release_idr;
 154                 /* replacing action and zone */
 155                 spin_lock_bh(&ci->tcf_lock);
 156                 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 157                 ci->zone = parm->zone;
 158                 spin_unlock_bh(&ci->tcf_lock);
 159                 if (goto_ch)
 160                         tcf_chain_put_by_act(goto_ch);
 161                 ret = 0;
 162         }
 163
 164         return ret;
 165 release_idr:
 166         tcf_idr_release(*a, bind);
 167         return err;
 168 }
 169
 170 static inline int tcf_connmark_dump(struct sk_buff *skb, struct tc_action *a,
 171                                     int bind, int ref)
 172 {
 173         unsigned char *b = skb_tail_pointer(skb);
 174         struct tcf_connmark_info *ci = to_connmark(a);
 175         struct tc_connmark opt = {
 176                 .index   = ci->tcf_index,
 177                 .refcnt  = refcount_read(&ci->tcf_refcnt) - ref,
 178                 .bindcnt = atomic_read(&ci->tcf_bindcnt) - bind,
 179         };
 180         struct tcf_t t;
 181
 182         spin_lock_bh(&ci->tcf_lock);
 183         opt.action = ci->tcf_action;
 184         opt.zone = ci->zone;
 185         if (nla_put(skb, TCA_CONNMARK_PARMS, sizeof(opt), &opt))
 186                 goto nla_put_failure;
 187
 188         tcf_tm_dump(&t, &ci->tcf_tm);
 189         if (nla_put_64bit(skb, TCA_CONNMARK_TM, sizeof(t), &t,
 190                           TCA_CONNMARK_PAD))
 191                 goto nla_put_failure;
 192         spin_unlock_bh(&ci->tcf_lock);
 193
 194         return skb->len;
 195
 196 nla_put_failure:
 197         spin_unlock_bh(&ci->tcf_lock);
 198         nlmsg_trim(skb, b);
 199         return -1;
 200 }
 201
 202 static struct tc_action_ops act_connmark_ops = {
 203         .kind           =       "connmark",
 204         .id             =       TCA_ID_CONNMARK,
 205         .owner          =       THIS_MODULE,
 206         .act            =       tcf_connmark_act,
 207         .dump           =       tcf_connmark_dump,
 208         .init           =       tcf_connmark_init,
 209         .size           =       sizeof(struct tcf_connmark_info),
 210 };
 211
 212 static __net_init int connmark_init_net(struct net *net)
 213 {
 214         struct tc_action_net *tn = net_generic(net, act_connmark_ops.net_id);
 215
 216         return tc_action_net_init(net, tn, &act_connmark_ops);
 217 }
 218
 219 static void __net_exit connmark_exit_net(struct list_head *net_list)
 220 {
 221         tc_action_net_exit(net_list, act_connmark_ops.net_id);
 222 }
 223
 224 static struct pernet_operations connmark_net_ops = {
 225         .init = connmark_init_net,
 226         .exit_batch = connmark_exit_net,
 227         .id   = &act_connmark_ops.net_id,
 228         .size = sizeof(struct tc_action_net),
 229 };
 230
 231 static int __init connmark_init_module(void)
 232 {
 233         return tcf_register_action(&act_connmark_ops, &connmark_net_ops);
 234 }
 235
 236 static void __exit connmark_cleanup_module(void)
 237 {
 238         tcf_unregister_action(&act_connmark_ops, &connmark_net_ops);
 239 }
 240
 241 module_init(connmark_init_module);
 242 module_exit(connmark_cleanup_module);
 243 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
 244 MODULE_DESCRIPTION("Connection tracking mark restoring");
 245 MODULE_LICENSE("GPL");