/* * net/sched/act_mirred.c packet mirroring and redirect actions * * 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. * * Authors: Jamal Hadi Salim (2002-4) * * TODO: Add ingress support (and socket redirect support) * */ #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/gfp.h> #include <linux/if_arp.h> #include <net/net_namespace.h> #include <net/netlink.h> #include <net/pkt_sched.h> #include <linux/tc_act/tc_mirred.h> #include <net/tc_act/tc_mirred.h> #include <linux/if_arp.h> #define MIRRED_TAB_MASK 7 static LIST_HEAD(mirred_list); static DEFINE_SPINLOCK(mirred_list_lock); static bool tcf_mirred_is_act_redirect(int action) { return action == TCA_EGRESS_REDIR || action == TCA_INGRESS_REDIR; } static bool tcf_mirred_act_wants_ingress(int action) { switch (action) { case TCA_EGRESS_REDIR: case TCA_EGRESS_MIRROR: return false; case TCA_INGRESS_REDIR: case TCA_INGRESS_MIRROR: return true; default: BUG(); } } static void tcf_mirred_release(struct tc_action *a, int bind) { struct tcf_mirred *m = to_mirred(a); struct net_device *dev; /* We could be called either in a RCU callback or with RTNL lock held. */ spin_lock_bh(&mirred_list_lock); list_del(&m->tcfm_list); dev = rcu_dereference_protected(m->tcfm_dev, 1); if (dev) dev_put(dev); spin_unlock_bh(&mirred_list_lock); } static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = { [TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) }, }; static unsigned int mirred_net_id; static struct tc_action_ops act_mirred_ops; static int tcf_mirred_init(struct net *net, struct nlattr *nla, struct nlattr *est, struct tc_action **a, int ovr, int bind) { struct tc_action_net *tn = net_generic(net, mirred_net_id); struct nlattr *tb[TCA_MIRRED_MAX + 1]; bool mac_header_xmit = false; struct tc_mirred *parm; struct tcf_mirred *m; struct net_device *dev; bool exists = false; int ret; if (nla == NULL) return -EINVAL; ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy); if (ret < 0) return ret; if (tb[TCA_MIRRED_PARMS] == NULL) return -EINVAL; parm = nla_data(tb[TCA_MIRRED_PARMS]); exists = tcf_hash_check(tn, parm->index, a, bind); if (exists && bind) return 0; switch (parm->eaction) { case TCA_EGRESS_MIRROR: case TCA_EGRESS_REDIR: case TCA_INGRESS_REDIR: case TCA_INGRESS_MIRROR: break; default: if (exists) tcf_hash_release(*a, bind); return -EINVAL; } if (parm->ifindex) { dev = __dev_get_by_index(net, parm->ifindex); if (dev == NULL) { if (exists) tcf_hash_release(*a, bind); return -ENODEV; } mac_header_xmit = dev_is_mac_header_xmit(dev); } else { dev = NULL; } if (!exists) { if (dev == NULL) return -EINVAL; ret = tcf_hash_create(tn, parm->index, est, a, &act_mirred_ops, bind, true); if (ret) return ret; ret = ACT_P_CREATED; } else { tcf_hash_release(*a, bind); if (!ovr) return -EEXIST; } m = to_mirred(*a); ASSERT_RTNL(); m->tcf_action = parm->action; m->tcfm_eaction = parm->eaction; if (dev != NULL) { m->tcfm_ifindex = parm->ifindex; if (ret != ACT_P_CREATED) dev_put(rcu_dereference_protected(m->tcfm_dev, 1)); dev_hold(dev); rcu_assign_pointer(m->tcfm_dev, dev); m->tcfm_mac_header_xmit = mac_header_xmit; } if (ret == ACT_P_CREATED) { spin_lock_bh(&mirred_list_lock); list_add(&m->tcfm_list, &mirred_list); spin_unlock_bh(&mirred_list_lock); tcf_hash_insert(tn, *a); } return ret; } static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a, struct tcf_result *res) { struct tcf_mirred *m = to_mirred(a); bool m_mac_header_xmit; struct net_device *dev; struct sk_buff *skb2; int retval, err = 0; int m_eaction; int mac_len; tcf_lastuse_update(&m->tcf_tm); bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb); rcu_read_lock(); m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit); m_eaction = READ_ONCE(m->tcfm_eaction); retval = READ_ONCE(m->tcf_action); dev = rcu_dereference(m->tcfm_dev); if (unlikely(!dev)) { pr_notice_once("tc mirred: target device is gone\n"); goto out; } if (unlikely(!(dev->flags & IFF_UP))) { net_notice_ratelimited("tc mirred to Houston: device %s is down\n", dev->name); goto out; } skb2 = skb_clone(skb, GFP_ATOMIC); if (!skb2) goto out; /* If action's target direction differs than filter's direction, * and devices expect a mac header on xmit, then mac push/pull is * needed. */ if (skb_at_tc_ingress(skb) != tcf_mirred_act_wants_ingress(m_eaction) && m_mac_header_xmit) { if (!skb_at_tc_ingress(skb)) { /* caught at egress, act ingress: pull mac */ mac_len = skb_network_header(skb) - skb_mac_header(skb); skb_pull_rcsum(skb2, mac_len); } else { /* caught at ingress, act egress: push mac */ skb_push_rcsum(skb2, skb->mac_len); } } /* mirror is always swallowed */ if (tcf_mirred_is_act_redirect(m_eaction)) { skb2->tc_redirected = 1; skb2->tc_from_ingress = skb2->tc_at_ingress; } skb2->skb_iif = skb->dev->ifindex; skb2->dev = dev; if (!tcf_mirred_act_wants_ingress(m_eaction)) err = dev_queue_xmit(skb2); else err = netif_receive_skb(skb2); if (err) { out: qstats_overlimit_inc(this_cpu_ptr(m->common.cpu_qstats)); if (tcf_mirred_is_act_redirect(m_eaction)) retval = TC_ACT_SHOT; } rcu_read_unlock(); return retval; } static void tcf_stats_update(struct tc_action *a, u64 bytes, u32 packets, u64 lastuse) { struct tcf_mirred *m = to_mirred(a); struct tcf_t *tm = &m->tcf_tm; _bstats_cpu_update(this_cpu_ptr(a->cpu_bstats), bytes, packets); tm->lastuse = lastuse; } static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) { unsigned char *b = skb_tail_pointer(skb); struct tcf_mirred *m = to_mirred(a); struct tc_mirred opt = { .index = m->tcf_index, .action = m->tcf_action, .refcnt = m->tcf_refcnt - ref, .bindcnt = m->tcf_bindcnt - bind, .eaction = m->tcfm_eaction, .ifindex = m->tcfm_ifindex, }; struct tcf_t t; if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt)) goto nla_put_failure; tcf_tm_dump(&t, &m->tcf_tm); if (nla_put_64bit(skb, TCA_MIRRED_TM, sizeof(t), &t, TCA_MIRRED_PAD)) goto nla_put_failure; return skb->len; nla_put_failure: nlmsg_trim(skb, b); return -1; } static int tcf_mirred_walker(struct net *net, struct sk_buff *skb, struct netlink_callback *cb, int type, const struct tc_action_ops *ops) { struct tc_action_net *tn = net_generic(net, mirred_net_id); return tcf_generic_walker(tn, skb, cb, type, ops); } static int tcf_mirred_search(struct net *net, struct tc_action **a, u32 index) { struct tc_action_net *tn = net_generic(net, mirred_net_id); return tcf_hash_search(tn, a, index); } static int mirred_device_event(struct notifier_block *unused, unsigned long event, void *ptr) { struct net_device *dev = netdev_notifier_info_to_dev(ptr); struct tcf_mirred *m; ASSERT_RTNL(); if (event == NETDEV_UNREGISTER) { spin_lock_bh(&mirred_list_lock); list_for_each_entry(m, &mirred_list, tcfm_list) { if (rcu_access_pointer(m->tcfm_dev) == dev) { dev_put(dev); /* Note : no rcu grace period necessary, as * net_device are already rcu protected. */ RCU_INIT_POINTER(m->tcfm_dev, NULL); } } spin_unlock_bh(&mirred_list_lock); } return NOTIFY_DONE; } static struct notifier_block mirred_device_notifier = { .notifier_call = mirred_device_event, }; static int tcf_mirred_device(const struct tc_action *a, struct net *net, struct net_device **mirred_dev) { int ifindex = tcf_mirred_ifindex(a); *mirred_dev = __dev_get_by_index(net, ifindex); if (!*mirred_dev) return -EINVAL; return 0; } static struct tc_action_ops act_mirred_ops = { .kind = "mirred", .type = TCA_ACT_MIRRED, .owner = THIS_MODULE, .act = tcf_mirred, .stats_update = tcf_stats_update, .dump = tcf_mirred_dump, .cleanup = tcf_mirred_release, .init = tcf_mirred_init, .walk = tcf_mirred_walker, .lookup = tcf_mirred_search, .size = sizeof(struct tcf_mirred), .get_dev = tcf_mirred_device, }; static __net_init int mirred_init_net(struct net *net) { struct tc_action_net *tn = net_generic(net, mirred_net_id); return tc_action_net_init(tn, &act_mirred_ops, MIRRED_TAB_MASK); } static void __net_exit mirred_exit_net(struct net *net) { struct tc_action_net *tn = net_generic(net, mirred_net_id); tc_action_net_exit(tn); } static struct pernet_operations mirred_net_ops = { .init = mirred_init_net, .exit = mirred_exit_net, .id = &mirred_net_id, .size = sizeof(struct tc_action_net), }; MODULE_AUTHOR("Jamal Hadi Salim(2002)"); MODULE_DESCRIPTION("Device Mirror/redirect actions"); MODULE_LICENSE("GPL"); static int __init mirred_init_module(void) { int err = register_netdevice_notifier(&mirred_device_notifier); if (err) return err; pr_info("Mirror/redirect action on\n"); return tcf_register_action(&act_mirred_ops, &mirred_net_ops); } static void __exit mirred_cleanup_module(void) { tcf_unregister_action(&act_mirred_ops, &mirred_net_ops); unregister_netdevice_notifier(&mirred_device_notifier); } module_init(mirred_init_module); module_exit(mirred_cleanup_module);