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