| /* |
| * 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> |
| |
| static LIST_HEAD(mirred_list); |
| |
| 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) |
| { |
| struct tcf_mirred *m = to_mirred(a); |
| struct net_device *dev; |
| |
| list_del(&m->tcfm_list); |
| dev = rtnl_dereference(m->tcfm_dev); |
| if (dev) |
| dev_put(dev); |
| } |
| |
| 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, bool rtnl_held, |
| struct netlink_ext_ack *extack) |
| { |
| 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, err; |
| |
| if (!nla) { |
| NL_SET_ERR_MSG_MOD(extack, "Mirred requires attributes to be passed"); |
| return -EINVAL; |
| } |
| ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy, extack); |
| if (ret < 0) |
| return ret; |
| if (!tb[TCA_MIRRED_PARMS]) { |
| NL_SET_ERR_MSG_MOD(extack, "Missing required mirred parameters"); |
| return -EINVAL; |
| } |
| parm = nla_data(tb[TCA_MIRRED_PARMS]); |
| |
| err = tcf_idr_check_alloc(tn, &parm->index, a, bind); |
| if (err < 0) |
| return err; |
| exists = err; |
| 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_idr_release(*a, bind); |
| else |
| tcf_idr_cleanup(tn, parm->index); |
| NL_SET_ERR_MSG_MOD(extack, "Unknown mirred option"); |
| return -EINVAL; |
| } |
| if (parm->ifindex) { |
| dev = __dev_get_by_index(net, parm->ifindex); |
| if (dev == NULL) { |
| if (exists) |
| tcf_idr_release(*a, bind); |
| else |
| tcf_idr_cleanup(tn, parm->index); |
| return -ENODEV; |
| } |
| mac_header_xmit = dev_is_mac_header_xmit(dev); |
| } else { |
| dev = NULL; |
| } |
| |
| if (!exists) { |
| if (!dev) { |
| tcf_idr_cleanup(tn, parm->index); |
| NL_SET_ERR_MSG_MOD(extack, "Specified device does not exist"); |
| return -EINVAL; |
| } |
| ret = tcf_idr_create(tn, parm->index, est, a, |
| &act_mirred_ops, bind, true); |
| if (ret) { |
| tcf_idr_cleanup(tn, parm->index); |
| return ret; |
| } |
| ret = ACT_P_CREATED; |
| } else if (!ovr) { |
| tcf_idr_release(*a, bind); |
| return -EEXIST; |
| } |
| m = to_mirred(*a); |
| |
| ASSERT_RTNL(); |
| m->tcf_action = parm->action; |
| m->tcfm_eaction = parm->eaction; |
| if (dev != NULL) { |
| 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) { |
| list_add(&m->tcfm_list, &mirred_list); |
| tcf_idr_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 = max_t(u64, 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 net_device *dev = rtnl_dereference(m->tcfm_dev); |
| struct tc_mirred opt = { |
| .index = m->tcf_index, |
| .action = m->tcf_action, |
| .refcnt = refcount_read(&m->tcf_refcnt) - ref, |
| .bindcnt = atomic_read(&m->tcf_bindcnt) - bind, |
| .eaction = m->tcfm_eaction, |
| .ifindex = dev ? dev->ifindex : 0, |
| }; |
| 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 netlink_ext_ack *extack) |
| { |
| struct tc_action_net *tn = net_generic(net, mirred_net_id); |
| |
| return tcf_generic_walker(tn, skb, cb, type, ops, extack); |
| } |
| |
| static int tcf_mirred_search(struct net *net, struct tc_action **a, u32 index, |
| struct netlink_ext_ack *extack) |
| { |
| struct tc_action_net *tn = net_generic(net, mirred_net_id); |
| |
| return tcf_idr_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) { |
| 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); |
| } |
| } |
| } |
| |
| return NOTIFY_DONE; |
| } |
| |
| static struct notifier_block mirred_device_notifier = { |
| .notifier_call = mirred_device_event, |
| }; |
| |
| static struct net_device *tcf_mirred_get_dev(const struct tc_action *a) |
| { |
| struct tcf_mirred *m = to_mirred(a); |
| |
| return rtnl_dereference(m->tcfm_dev); |
| } |
| |
| static int tcf_mirred_delete(struct net *net, u32 index) |
| { |
| struct tc_action_net *tn = net_generic(net, mirred_net_id); |
| |
| return tcf_idr_delete_index(tn, index); |
| } |
| |
| 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_get_dev, |
| .delete = tcf_mirred_delete, |
| }; |
| |
| 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); |
| } |
| |
| static void __net_exit mirred_exit_net(struct list_head *net_list) |
| { |
| tc_action_net_exit(net_list, mirred_net_id); |
| } |
| |
| static struct pernet_operations mirred_net_ops = { |
| .init = mirred_init_net, |
| .exit_batch = 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); |