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         if (skb->protocol == htons(ETH_P_IP)) {
  47                 if (skb->len < sizeof(struct iphdr))
  48                         goto out;
  49
  50                 proto = NFPROTO_IPV4;
  51         } else if (skb->protocol == htons(ETH_P_IPV6)) {
  52                 if (skb->len < sizeof(struct ipv6hdr))
  53                         goto out;
  54
  55                 proto = NFPROTO_IPV6;
  56         } else {
  57                 goto out;
  58         }
  59
  60         c = nf_ct_get(skb, &ctinfo);
  61         if (c) {
  62                 skb->mark = c->mark;
  63                 /* using overlimits stats to count how many packets marked */
  64                 ca->tcf_qstats.overlimits++;
  65                 goto out;
  66         }
  67
  68         if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
  69                                proto, ca->net, &tuple))
  70                 goto out;
  71
  72         zone.id = ca->zone;
  73         zone.dir = NF_CT_DEFAULT_ZONE_DIR;
  74
  75         thash = nf_conntrack_find_get(ca->net, &zone, &tuple);
  76         if (!thash)
  77                 goto out;
  78
  79         c = nf_ct_tuplehash_to_ctrack(thash);
  80         /* using overlimits stats to count how many packets marked */
  81         ca->tcf_qstats.overlimits++;
  82         skb->mark = c->mark;
  83         nf_ct_put(c);
  84
  85 out:
  86         spin_unlock(&ca->tcf_lock);
  87         return ca->tcf_action;
  88 }
  89
  90 static const struct nla_policy connmark_policy[TCA_CONNMARK_MAX + 1] = {
  91         [TCA_CONNMARK_PARMS] = { .len = sizeof(struct tc_connmark) },
  92 };
  93
  94 static int tcf_connmark_init(struct net *net, struct nlattr *nla,
  95                              struct nlattr *est, struct tc_action **a,
  96                              int ovr, int bind, bool rtnl_held,
  97                              struct tcf_proto *tp,
  98                              struct netlink_ext_ack *extack)
  99 {
 100         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 101         struct nlattr *tb[TCA_CONNMARK_MAX + 1];
 102         struct tcf_chain *goto_ch = NULL;
 103         struct tcf_connmark_info *ci;
 104         struct tc_connmark *parm;
 105         int ret = 0, err;
 106
 107         if (!nla)
 108                 return -EINVAL;
 109
 110         ret = nla_parse_nested_deprecated(tb, TCA_CONNMARK_MAX, nla,
 111                                           connmark_policy, NULL);
 112         if (ret < 0)
 113                 return ret;
 114
 115         if (!tb[TCA_CONNMARK_PARMS])
 116                 return -EINVAL;
 117
 118         parm = nla_data(tb[TCA_CONNMARK_PARMS]);
 119
 120         ret = tcf_idr_check_alloc(tn, &parm->index, a, bind);
 121         if (!ret) {
 122                 ret = tcf_idr_create(tn, parm->index, est, a,
 123                                      &act_connmark_ops, bind, false);
 124                 if (ret) {
 125                         tcf_idr_cleanup(tn, parm->index);
 126                         return ret;
 127                 }
 128
 129                 ci = to_connmark(*a);
 130                 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch,
 131                                                extack);
 132                 if (err < 0)
 133                         goto release_idr;
 134                 tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 135                 ci->net = net;
 136                 ci->zone = parm->zone;
 137
 138                 tcf_idr_insert(tn, *a);
 139                 ret = ACT_P_CREATED;
 140         } else if (ret > 0) {
 141                 ci = to_connmark(*a);
 142                 if (bind)
 143                         return 0;
 144                 if (!ovr) {
 145                         tcf_idr_release(*a, bind);
 146                         return -EEXIST;
 147                 }
 148                 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch,
 149                                                extack);
 150                 if (err < 0)
 151                         goto release_idr;
 152                 /* replacing action and zone */
 153                 spin_lock_bh(&ci->tcf_lock);
 154                 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 155                 ci->zone = parm->zone;
 156                 spin_unlock_bh(&ci->tcf_lock);
 157                 if (goto_ch)
 158                         tcf_chain_put_by_act(goto_ch);
 159                 ret = 0;
 160         }
 161
 162         return ret;
 163 release_idr:
 164         tcf_idr_release(*a, bind);
 165         return err;
 166 }
 167
 168 static inline int tcf_connmark_dump(struct sk_buff *skb, struct tc_action *a,
 169                                     int bind, int ref)
 170 {
 171         unsigned char *b = skb_tail_pointer(skb);
 172         struct tcf_connmark_info *ci = to_connmark(a);
 173         struct tc_connmark opt = {
 174                 .index   = ci->tcf_index,
 175                 .refcnt  = refcount_read(&ci->tcf_refcnt) - ref,
 176                 .bindcnt = atomic_read(&ci->tcf_bindcnt) - bind,
 177         };
 178         struct tcf_t t;
 179
 180         spin_lock_bh(&ci->tcf_lock);
 181         opt.action = ci->tcf_action;
 182         opt.zone = ci->zone;
 183         if (nla_put(skb, TCA_CONNMARK_PARMS, sizeof(opt), &opt))
 184                 goto nla_put_failure;
 185
 186         tcf_tm_dump(&t, &ci->tcf_tm);
 187         if (nla_put_64bit(skb, TCA_CONNMARK_TM, sizeof(t), &t,
 188                           TCA_CONNMARK_PAD))
 189                 goto nla_put_failure;
 190         spin_unlock_bh(&ci->tcf_lock);
 191
 192         return skb->len;
 193
 194 nla_put_failure:
 195         spin_unlock_bh(&ci->tcf_lock);
 196         nlmsg_trim(skb, b);
 197         return -1;
 198 }
 199
 200 static int tcf_connmark_walker(struct net *net, struct sk_buff *skb,
 201                                struct netlink_callback *cb, int type,
 202                                const struct tc_action_ops *ops,
 203                                struct netlink_ext_ack *extack)
 204 {
 205         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 206
 207         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 208 }
 209
 210 static int tcf_connmark_search(struct net *net, struct tc_action **a, u32 index)
 211 {
 212         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 213
 214         return tcf_idr_search(tn, a, index);
 215 }
 216
 217 static struct tc_action_ops act_connmark_ops = {
 218         .kind           =       "connmark",
 219         .id             =       TCA_ID_CONNMARK,
 220         .owner          =       THIS_MODULE,
 221         .act            =       tcf_connmark_act,
 222         .dump           =       tcf_connmark_dump,
 223         .init           =       tcf_connmark_init,
 224         .walk           =       tcf_connmark_walker,
 225         .lookup         =       tcf_connmark_search,
 226         .size           =       sizeof(struct tcf_connmark_info),
 227 };
 228
 229 static __net_init int connmark_init_net(struct net *net)
 230 {
 231         struct tc_action_net *tn = net_generic(net, connmark_net_id);
 232
 233         return tc_action_net_init(tn, &act_connmark_ops);
 234 }
 235
 236 static void __net_exit connmark_exit_net(struct list_head *net_list)
 237 {
 238         tc_action_net_exit(net_list, connmark_net_id);
 239 }
 240
 241 static struct pernet_operations connmark_net_ops = {
 242         .init = connmark_init_net,
 243         .exit_batch = connmark_exit_net,
 244         .id   = &connmark_net_id,
 245         .size = sizeof(struct tc_action_net),
 246 };
 247
 248 static int __init connmark_init_module(void)
 249 {
 250         return tcf_register_action(&act_connmark_ops, &connmark_net_ops);
 251 }
 252
 253 static void __exit connmark_cleanup_module(void)
 254 {
 255         tcf_unregister_action(&act_connmark_ops, &connmark_net_ops);
 256 }
 257
 258 module_init(connmark_init_module);
 259 module_exit(connmark_cleanup_module);
 260 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
 261 MODULE_DESCRIPTION("Connection tracking mark restoring");
 262 MODULE_LICENSE("GPL");