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 unsigned 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 NULL); 114 if (ret < 0) 115 return ret; 116 117 if (!tb[TCA_CONNMARK_PARMS]) 118 return -EINVAL; 119 120 parm = nla_data(tb[TCA_CONNMARK_PARMS]); 121 122 if (!tcf_hash_check(tn, parm->index, a, bind)) { 123 ret = tcf_hash_create(tn, parm->index, est, a, 124 &act_connmark_ops, bind, false); 125 if (ret) 126 return ret; 127 128 ci = to_connmark(*a); 129 ci->tcf_action = parm->action; 130 ci->net = net; 131 ci->zone = parm->zone; 132 133 tcf_hash_insert(tn, *a); 134 ret = ACT_P_CREATED; 135 } else { 136 ci = to_connmark(*a); 137 if (bind) 138 return 0; 139 tcf_hash_release(*a, bind); 140 if (!ovr) 141 return -EEXIST; 142 /* replacing action and zone */ 143 ci->tcf_action = parm->action; 144 ci->zone = parm->zone; 145 } 146 147 return ret; 148 } 149 150 static inline int tcf_connmark_dump(struct sk_buff *skb, struct tc_action *a, 151 int bind, int ref) 152 { 153 unsigned char *b = skb_tail_pointer(skb); 154 struct tcf_connmark_info *ci = to_connmark(a); 155 156 struct tc_connmark opt = { 157 .index = ci->tcf_index, 158 .refcnt = ci->tcf_refcnt - ref, 159 .bindcnt = ci->tcf_bindcnt - bind, 160 .action = ci->tcf_action, 161 .zone = ci->zone, 162 }; 163 struct tcf_t t; 164 165 if (nla_put(skb, TCA_CONNMARK_PARMS, sizeof(opt), &opt)) 166 goto nla_put_failure; 167 168 tcf_tm_dump(&t, &ci->tcf_tm); 169 if (nla_put_64bit(skb, TCA_CONNMARK_TM, sizeof(t), &t, 170 TCA_CONNMARK_PAD)) 171 goto nla_put_failure; 172 173 return skb->len; 174 nla_put_failure: 175 nlmsg_trim(skb, b); 176 return -1; 177 } 178 179 static int tcf_connmark_walker(struct net *net, struct sk_buff *skb, 180 struct netlink_callback *cb, int type, 181 const struct tc_action_ops *ops) 182 { 183 struct tc_action_net *tn = net_generic(net, connmark_net_id); 184 185 return tcf_generic_walker(tn, skb, cb, type, ops); 186 } 187 188 static int tcf_connmark_search(struct net *net, struct tc_action **a, u32 index) 189 { 190 struct tc_action_net *tn = net_generic(net, connmark_net_id); 191 192 return tcf_hash_search(tn, a, index); 193 } 194 195 static struct tc_action_ops act_connmark_ops = { 196 .kind = "connmark", 197 .type = TCA_ACT_CONNMARK, 198 .owner = THIS_MODULE, 199 .act = tcf_connmark, 200 .dump = tcf_connmark_dump, 201 .init = tcf_connmark_init, 202 .walk = tcf_connmark_walker, 203 .lookup = tcf_connmark_search, 204 .size = sizeof(struct tcf_connmark_info), 205 }; 206 207 static __net_init int connmark_init_net(struct net *net) 208 { 209 struct tc_action_net *tn = net_generic(net, connmark_net_id); 210 211 return tc_action_net_init(tn, &act_connmark_ops, CONNMARK_TAB_MASK); 212 } 213 214 static void __net_exit connmark_exit_net(struct net *net) 215 { 216 struct tc_action_net *tn = net_generic(net, connmark_net_id); 217 218 tc_action_net_exit(tn); 219 } 220 221 static struct pernet_operations connmark_net_ops = { 222 .init = connmark_init_net, 223 .exit = connmark_exit_net, 224 .id = &connmark_net_id, 225 .size = sizeof(struct tc_action_net), 226 }; 227 228 static int __init connmark_init_module(void) 229 { 230 return tcf_register_action(&act_connmark_ops, &connmark_net_ops); 231 } 232 233 static void __exit connmark_cleanup_module(void) 234 { 235 tcf_unregister_action(&act_connmark_ops, &connmark_net_ops); 236 } 237 238 module_init(connmark_init_module); 239 module_exit(connmark_cleanup_module); 240 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>"); 241 MODULE_DESCRIPTION("Connection tracking mark restoring"); 242 MODULE_LICENSE("GPL"); 243 244