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