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 <uapi/linux/tc_act/tc_connmark.h> 25 #include <net/tc_act/tc_connmark.h> 26 27 #include <net/netfilter/nf_conntrack.h> 28 #include <net/netfilter/nf_conntrack_core.h> 29 #include <net/netfilter/nf_conntrack_zones.h> 30 31 #define CONNMARK_TAB_MASK 3 32 33 static int connmark_net_id; 34 static struct tc_action_ops act_connmark_ops; 35 36 static int tcf_connmark(struct sk_buff *skb, const struct tc_action *a, 37 struct tcf_result *res) 38 { 39 const struct nf_conntrack_tuple_hash *thash; 40 struct nf_conntrack_tuple tuple; 41 enum ip_conntrack_info ctinfo; 42 struct tcf_connmark_info *ca = to_connmark(a); 43 struct nf_conntrack_zone zone; 44 struct nf_conn *c; 45 int proto; 46 47 spin_lock(&ca->tcf_lock); 48 tcf_lastuse_update(&ca->tcf_tm); 49 bstats_update(&ca->tcf_bstats, skb); 50 51 if (skb->protocol == htons(ETH_P_IP)) { 52 if (skb->len < sizeof(struct iphdr)) 53 goto out; 54 55 proto = NFPROTO_IPV4; 56 } else if (skb->protocol == htons(ETH_P_IPV6)) { 57 if (skb->len < sizeof(struct ipv6hdr)) 58 goto out; 59 60 proto = NFPROTO_IPV6; 61 } else { 62 goto out; 63 } 64 65 c = nf_ct_get(skb, &ctinfo); 66 if (c) { 67 skb->mark = c->mark; 68 /* using overlimits stats to count how many packets marked */ 69 ca->tcf_qstats.overlimits++; 70 goto out; 71 } 72 73 if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb), 74 proto, ca->net, &tuple)) 75 goto out; 76 77 zone.id = ca->zone; 78 zone.dir = NF_CT_DEFAULT_ZONE_DIR; 79 80 thash = nf_conntrack_find_get(ca->net, &zone, &tuple); 81 if (!thash) 82 goto out; 83 84 c = nf_ct_tuplehash_to_ctrack(thash); 85 /* using overlimits stats to count how many packets marked */ 86 ca->tcf_qstats.overlimits++; 87 skb->mark = c->mark; 88 nf_ct_put(c); 89 90 out: 91 spin_unlock(&ca->tcf_lock); 92 return ca->tcf_action; 93 } 94 95 static const struct nla_policy connmark_policy[TCA_CONNMARK_MAX + 1] = { 96 [TCA_CONNMARK_PARMS] = { .len = sizeof(struct tc_connmark) }, 97 }; 98 99 static int tcf_connmark_init(struct net *net, struct nlattr *nla, 100 struct nlattr *est, struct tc_action **a, 101 int ovr, int bind) 102 { 103 struct tc_action_net *tn = net_generic(net, connmark_net_id); 104 struct nlattr *tb[TCA_CONNMARK_MAX + 1]; 105 struct tcf_connmark_info *ci; 106 struct tc_connmark *parm; 107 int ret = 0; 108 109 if (!nla) 110 return -EINVAL; 111 112 ret = nla_parse_nested(tb, TCA_CONNMARK_MAX, nla, connmark_policy); 113 if (ret < 0) 114 return ret; 115 116 parm = nla_data(tb[TCA_CONNMARK_PARMS]); 117 118 if (!tcf_hash_check(tn, parm->index, a, bind)) { 119 ret = tcf_hash_create(tn, parm->index, est, a, 120 &act_connmark_ops, bind, false); 121 if (ret) 122 return ret; 123 124 ci = to_connmark(*a); 125 ci->tcf_action = parm->action; 126 ci->net = net; 127 ci->zone = parm->zone; 128 129 tcf_hash_insert(tn, *a); 130 ret = ACT_P_CREATED; 131 } else { 132 ci = to_connmark(*a); 133 if (bind) 134 return 0; 135 tcf_hash_release(*a, bind); 136 if (!ovr) 137 return -EEXIST; 138 /* replacing action and zone */ 139 ci->tcf_action = parm->action; 140 ci->zone = parm->zone; 141 } 142 143 return ret; 144 } 145 146 static inline int tcf_connmark_dump(struct sk_buff *skb, struct tc_action *a, 147 int bind, int ref) 148 { 149 unsigned char *b = skb_tail_pointer(skb); 150 struct tcf_connmark_info *ci = to_connmark(a); 151 152 struct tc_connmark opt = { 153 .index = ci->tcf_index, 154 .refcnt = ci->tcf_refcnt - ref, 155 .bindcnt = ci->tcf_bindcnt - bind, 156 .action = ci->tcf_action, 157 .zone = ci->zone, 158 }; 159 struct tcf_t t; 160 161 if (nla_put(skb, TCA_CONNMARK_PARMS, sizeof(opt), &opt)) 162 goto nla_put_failure; 163 164 tcf_tm_dump(&t, &ci->tcf_tm); 165 if (nla_put_64bit(skb, TCA_CONNMARK_TM, sizeof(t), &t, 166 TCA_CONNMARK_PAD)) 167 goto nla_put_failure; 168 169 return skb->len; 170 nla_put_failure: 171 nlmsg_trim(skb, b); 172 return -1; 173 } 174 175 static int tcf_connmark_walker(struct net *net, struct sk_buff *skb, 176 struct netlink_callback *cb, int type, 177 const struct tc_action_ops *ops) 178 { 179 struct tc_action_net *tn = net_generic(net, connmark_net_id); 180 181 return tcf_generic_walker(tn, skb, cb, type, ops); 182 } 183 184 static int tcf_connmark_search(struct net *net, struct tc_action **a, u32 index) 185 { 186 struct tc_action_net *tn = net_generic(net, connmark_net_id); 187 188 return tcf_hash_search(tn, a, index); 189 } 190 191 static struct tc_action_ops act_connmark_ops = { 192 .kind = "connmark", 193 .type = TCA_ACT_CONNMARK, 194 .owner = THIS_MODULE, 195 .act = tcf_connmark, 196 .dump = tcf_connmark_dump, 197 .init = tcf_connmark_init, 198 .walk = tcf_connmark_walker, 199 .lookup = tcf_connmark_search, 200 .size = sizeof(struct tcf_connmark_info), 201 }; 202 203 static __net_init int connmark_init_net(struct net *net) 204 { 205 struct tc_action_net *tn = net_generic(net, connmark_net_id); 206 207 return tc_action_net_init(tn, &act_connmark_ops, CONNMARK_TAB_MASK); 208 } 209 210 static void __net_exit connmark_exit_net(struct net *net) 211 { 212 struct tc_action_net *tn = net_generic(net, connmark_net_id); 213 214 tc_action_net_exit(tn); 215 } 216 217 static struct pernet_operations connmark_net_ops = { 218 .init = connmark_init_net, 219 .exit = connmark_exit_net, 220 .id = &connmark_net_id, 221 .size = sizeof(struct tc_action_net), 222 }; 223 224 static int __init connmark_init_module(void) 225 { 226 return tcf_register_action(&act_connmark_ops, &connmark_net_ops); 227 } 228 229 static void __exit connmark_cleanup_module(void) 230 { 231 tcf_unregister_action(&act_connmark_ops, &connmark_net_ops); 232 } 233 234 module_init(connmark_init_module); 235 module_exit(connmark_cleanup_module); 236 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>"); 237 MODULE_DESCRIPTION("Connection tracking mark restoring"); 238 MODULE_LICENSE("GPL"); 239 240