/* * net/sched/act_ipt.c iptables target interface * *TODO: Add other tables. For now we only support the ipv4 table targets * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * Copyright: Jamal Hadi Salim (2002-13) */ #include <linux/types.h> #include <linux/kernel.h> #include <linux/string.h> #include <linux/errno.h> #include <linux/skbuff.h> #include <linux/rtnetlink.h> #include <linux/module.h> #include <linux/init.h> #include <linux/slab.h> #include <net/netlink.h> #include <net/pkt_sched.h> #include <linux/tc_act/tc_ipt.h> #include <net/tc_act/tc_ipt.h> #include <linux/netfilter_ipv4/ip_tables.h> static unsigned int ipt_net_id; static struct tc_action_ops act_ipt_ops; static unsigned int xt_net_id; static struct tc_action_ops act_xt_ops; static int ipt_init_target(struct net *net, struct xt_entry_target *t, char *table, unsigned int hook) { struct xt_tgchk_param par; struct xt_target *target; struct ipt_entry e = {}; int ret = 0; target = xt_request_find_target(AF_INET, t->u.user.name, t->u.user.revision); if (IS_ERR(target)) return PTR_ERR(target); t->u.kernel.target = target; memset(&par, 0, sizeof(par)); par.net = net; par.table = table; par.entryinfo = &e; par.target = target; par.targinfo = t->data; par.hook_mask = hook; par.family = NFPROTO_IPV4; ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false); if (ret < 0) { module_put(t->u.kernel.target->me); return ret; } return 0; } static void ipt_destroy_target(struct xt_entry_target *t) { struct xt_tgdtor_param par = { .target = t->u.kernel.target, .targinfo = t->data, .family = NFPROTO_IPV4, }; if (par.target->destroy != NULL) par.target->destroy(&par); module_put(par.target->me); } static void tcf_ipt_release(struct tc_action *a) { struct tcf_ipt *ipt = to_ipt(a); if (ipt->tcfi_t) { ipt_destroy_target(ipt->tcfi_t); kfree(ipt->tcfi_t); } kfree(ipt->tcfi_tname); } static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = { [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ }, [TCA_IPT_HOOK] = { .type = NLA_U32 }, [TCA_IPT_INDEX] = { .type = NLA_U32 }, [TCA_IPT_TARG] = { .len = sizeof(struct xt_entry_target) }, }; static int __tcf_ipt_init(struct net *net, unsigned int id, struct nlattr *nla, struct nlattr *est, struct tc_action **a, const struct tc_action_ops *ops, int ovr, int bind) { struct tc_action_net *tn = net_generic(net, id); struct nlattr *tb[TCA_IPT_MAX + 1]; struct tcf_ipt *ipt; struct xt_entry_target *td, *t; char *tname; bool exists = false; int ret = 0, err; u32 hook = 0; u32 index = 0; if (nla == NULL) return -EINVAL; err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy, NULL); if (err < 0) return err; if (tb[TCA_IPT_INDEX] != NULL) index = nla_get_u32(tb[TCA_IPT_INDEX]); err = tcf_idr_check_alloc(tn, &index, a, bind); if (err < 0) return err; exists = err; if (exists && bind) return 0; if (tb[TCA_IPT_HOOK] == NULL || tb[TCA_IPT_TARG] == NULL) { if (exists) tcf_idr_release(*a, bind); else tcf_idr_cleanup(tn, index); return -EINVAL; } td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]); if (nla_len(tb[TCA_IPT_TARG]) != td->u.target_size) { if (exists) tcf_idr_release(*a, bind); else tcf_idr_cleanup(tn, index); return -EINVAL; } if (!exists) { ret = tcf_idr_create(tn, index, est, a, ops, bind, false); if (ret) { tcf_idr_cleanup(tn, index); return ret; } ret = ACT_P_CREATED; } else { if (bind)/* dont override defaults */ return 0; if (!ovr) { tcf_idr_release(*a, bind); return -EEXIST; } } hook = nla_get_u32(tb[TCA_IPT_HOOK]); err = -ENOMEM; tname = kmalloc(IFNAMSIZ, GFP_KERNEL); if (unlikely(!tname)) goto err1; if (tb[TCA_IPT_TABLE] == NULL || nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ) strcpy(tname, "mangle"); t = kmemdup(td, td->u.target_size, GFP_KERNEL); if (unlikely(!t)) goto err2; err = ipt_init_target(net, t, tname, hook); if (err < 0) goto err3; ipt = to_ipt(*a); spin_lock_bh(&ipt->tcf_lock); if (ret != ACT_P_CREATED) { ipt_destroy_target(ipt->tcfi_t); kfree(ipt->tcfi_tname); kfree(ipt->tcfi_t); } ipt->tcfi_tname = tname; ipt->tcfi_t = t; ipt->tcfi_hook = hook; spin_unlock_bh(&ipt->tcf_lock); if (ret == ACT_P_CREATED) tcf_idr_insert(tn, *a); return ret; err3: kfree(t); err2: kfree(tname); err1: tcf_idr_release(*a, bind); return err; } static int tcf_ipt_init(struct net *net, struct nlattr *nla, struct nlattr *est, struct tc_action **a, int ovr, int bind, bool rtnl_held, struct netlink_ext_ack *extack) { return __tcf_ipt_init(net, ipt_net_id, nla, est, a, &act_ipt_ops, ovr, bind); } static int tcf_xt_init(struct net *net, struct nlattr *nla, struct nlattr *est, struct tc_action **a, int ovr, int bind, bool unlocked, struct netlink_ext_ack *extack) { return __tcf_ipt_init(net, xt_net_id, nla, est, a, &act_xt_ops, ovr, bind); } static int tcf_ipt_act(struct sk_buff *skb, const struct tc_action *a, struct tcf_result *res) { int ret = 0, result = 0; struct tcf_ipt *ipt = to_ipt(a); struct xt_action_param par; struct nf_hook_state state = { .net = dev_net(skb->dev), .in = skb->dev, .hook = ipt->tcfi_hook, .pf = NFPROTO_IPV4, }; if (skb_unclone(skb, GFP_ATOMIC)) return TC_ACT_UNSPEC; spin_lock(&ipt->tcf_lock); tcf_lastuse_update(&ipt->tcf_tm); bstats_update(&ipt->tcf_bstats, skb); /* yes, we have to worry about both in and out dev * worry later - danger - this API seems to have changed * from earlier kernels */ par.state = &state; par.target = ipt->tcfi_t->u.kernel.target; par.targinfo = ipt->tcfi_t->data; ret = par.target->target(skb, &par); switch (ret) { case NF_ACCEPT: result = TC_ACT_OK; break; case NF_DROP: result = TC_ACT_SHOT; ipt->tcf_qstats.drops++; break; case XT_CONTINUE: result = TC_ACT_PIPE; break; default: net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n", ret); result = TC_ACT_OK; break; } spin_unlock(&ipt->tcf_lock); return result; } static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) { unsigned char *b = skb_tail_pointer(skb); struct tcf_ipt *ipt = to_ipt(a); struct xt_entry_target *t; struct tcf_t tm; struct tc_cnt c; /* for simple targets kernel size == user size * user name = target name * for foolproof you need to not assume this */ spin_lock_bh(&ipt->tcf_lock); t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC); if (unlikely(!t)) goto nla_put_failure; c.bindcnt = atomic_read(&ipt->tcf_bindcnt) - bind; c.refcnt = refcount_read(&ipt->tcf_refcnt) - ref; strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name); if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) || nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) || nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) || nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) || nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname)) goto nla_put_failure; tcf_tm_dump(&tm, &ipt->tcf_tm); if (nla_put_64bit(skb, TCA_IPT_TM, sizeof(tm), &tm, TCA_IPT_PAD)) goto nla_put_failure; spin_unlock_bh(&ipt->tcf_lock); kfree(t); return skb->len; nla_put_failure: spin_unlock_bh(&ipt->tcf_lock); nlmsg_trim(skb, b); kfree(t); return -1; } static int tcf_ipt_walker(struct net *net, struct sk_buff *skb, struct netlink_callback *cb, int type, const struct tc_action_ops *ops, struct netlink_ext_ack *extack) { struct tc_action_net *tn = net_generic(net, ipt_net_id); return tcf_generic_walker(tn, skb, cb, type, ops, extack); } static int tcf_ipt_search(struct net *net, struct tc_action **a, u32 index) { struct tc_action_net *tn = net_generic(net, ipt_net_id); return tcf_idr_search(tn, a, index); } static struct tc_action_ops act_ipt_ops = { .kind = "ipt", .id = TCA_ID_IPT, .owner = THIS_MODULE, .act = tcf_ipt_act, .dump = tcf_ipt_dump, .cleanup = tcf_ipt_release, .init = tcf_ipt_init, .walk = tcf_ipt_walker, .lookup = tcf_ipt_search, .size = sizeof(struct tcf_ipt), }; static __net_init int ipt_init_net(struct net *net) { struct tc_action_net *tn = net_generic(net, ipt_net_id); return tc_action_net_init(tn, &act_ipt_ops); } static void __net_exit ipt_exit_net(struct list_head *net_list) { tc_action_net_exit(net_list, ipt_net_id); } static struct pernet_operations ipt_net_ops = { .init = ipt_init_net, .exit_batch = ipt_exit_net, .id = &ipt_net_id, .size = sizeof(struct tc_action_net), }; static int tcf_xt_walker(struct net *net, struct sk_buff *skb, struct netlink_callback *cb, int type, const struct tc_action_ops *ops, struct netlink_ext_ack *extack) { struct tc_action_net *tn = net_generic(net, xt_net_id); return tcf_generic_walker(tn, skb, cb, type, ops, extack); } static int tcf_xt_search(struct net *net, struct tc_action **a, u32 index) { struct tc_action_net *tn = net_generic(net, xt_net_id); return tcf_idr_search(tn, a, index); } static struct tc_action_ops act_xt_ops = { .kind = "xt", .id = TCA_ID_XT, .owner = THIS_MODULE, .act = tcf_ipt_act, .dump = tcf_ipt_dump, .cleanup = tcf_ipt_release, .init = tcf_xt_init, .walk = tcf_xt_walker, .lookup = tcf_xt_search, .size = sizeof(struct tcf_ipt), }; static __net_init int xt_init_net(struct net *net) { struct tc_action_net *tn = net_generic(net, xt_net_id); return tc_action_net_init(tn, &act_xt_ops); } static void __net_exit xt_exit_net(struct list_head *net_list) { tc_action_net_exit(net_list, xt_net_id); } static struct pernet_operations xt_net_ops = { .init = xt_init_net, .exit_batch = xt_exit_net, .id = &xt_net_id, .size = sizeof(struct tc_action_net), }; MODULE_AUTHOR("Jamal Hadi Salim(2002-13)"); MODULE_DESCRIPTION("Iptables target actions"); MODULE_LICENSE("GPL"); MODULE_ALIAS("act_xt"); static int __init ipt_init_module(void) { int ret1, ret2; ret1 = tcf_register_action(&act_xt_ops, &xt_net_ops); if (ret1 < 0) pr_err("Failed to load xt action\n"); ret2 = tcf_register_action(&act_ipt_ops, &ipt_net_ops); if (ret2 < 0) pr_err("Failed to load ipt action\n"); if (ret1 < 0 && ret2 < 0) { return ret1; } else return 0; } static void __exit ipt_cleanup_module(void) { tcf_unregister_action(&act_ipt_ops, &ipt_net_ops); tcf_unregister_action(&act_xt_ops, &xt_net_ops); } module_init(ipt_init_module); module_exit(ipt_cleanup_module);