linux/net/sched/act_mirred.c
Pedro Tammela c2a67de9bb net/sched: introduce ACT_P_BOUND return code
Bound actions always return '0' and as of today we rely on '0'
being returned in order to properly skip bound actions in
tcf_idr_insert_many. In order to further improve maintainability,
introduce the ACT_P_BOUND return code.

Actions are updated to return 'ACT_P_BOUND' instead of plain '0'.
tcf_idr_insert_many is then updated to check for 'ACT_P_BOUND'.

Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://lore.kernel.org/r/20231229132642.1489088-1-pctammela@mojatatu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-01-03 18:36:24 -08:00

692 lines
17 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* net/sched/act_mirred.c packet mirroring and redirect actions
*
* 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/dst.h>
#include <net/pkt_sched.h>
#include <net/pkt_cls.h>
#include <linux/tc_act/tc_mirred.h>
#include <net/tc_act/tc_mirred.h>
#include <net/tc_wrapper.h>
static LIST_HEAD(mirred_list);
static DEFINE_SPINLOCK(mirred_list_lock);
#define MIRRED_NEST_LIMIT 4
static DEFINE_PER_CPU(unsigned int, mirred_nest_level);
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 bool tcf_mirred_can_reinsert(int action)
{
switch (action) {
case TC_ACT_SHOT:
case TC_ACT_STOLEN:
case TC_ACT_QUEUED:
case TC_ACT_TRAP:
return true;
}
return false;
}
static struct net_device *tcf_mirred_dev_dereference(struct tcf_mirred *m)
{
return rcu_dereference_protected(m->tcfm_dev,
lockdep_is_held(&m->tcf_lock));
}
static void tcf_mirred_release(struct tc_action *a)
{
struct tcf_mirred *m = to_mirred(a);
struct net_device *dev;
spin_lock(&mirred_list_lock);
list_del(&m->tcfm_list);
spin_unlock(&mirred_list_lock);
/* last reference to action, no need to lock */
dev = rcu_dereference_protected(m->tcfm_dev, 1);
netdev_put(dev, &m->tcfm_dev_tracker);
}
static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
[TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) },
[TCA_MIRRED_BLOCKID] = NLA_POLICY_MIN(NLA_U32, 1),
};
static struct tc_action_ops act_mirred_ops;
static void tcf_mirred_replace_dev(struct tcf_mirred *m,
struct net_device *ndev)
{
struct net_device *odev;
odev = rcu_replace_pointer(m->tcfm_dev, ndev,
lockdep_is_held(&m->tcf_lock));
netdev_put(odev, &m->tcfm_dev_tracker);
}
static int tcf_mirred_init(struct net *net, struct nlattr *nla,
struct nlattr *est, struct tc_action **a,
struct tcf_proto *tp,
u32 flags, struct netlink_ext_ack *extack)
{
struct tc_action_net *tn = net_generic(net, act_mirred_ops.net_id);
bool bind = flags & TCA_ACT_FLAGS_BIND;
struct nlattr *tb[TCA_MIRRED_MAX + 1];
struct tcf_chain *goto_ch = NULL;
bool mac_header_xmit = false;
struct tc_mirred *parm;
struct tcf_mirred *m;
bool exists = false;
int ret, err;
u32 index;
if (!nla) {
NL_SET_ERR_MSG_MOD(extack, "Mirred requires attributes to be passed");
return -EINVAL;
}
ret = nla_parse_nested_deprecated(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]);
index = parm->index;
err = tcf_idr_check_alloc(tn, &index, a, bind);
if (err < 0)
return err;
exists = err;
if (exists && bind)
return ACT_P_BOUND;
if (tb[TCA_MIRRED_BLOCKID] && parm->ifindex) {
NL_SET_ERR_MSG_MOD(extack,
"Cannot specify Block ID and dev simultaneously");
if (exists)
tcf_idr_release(*a, bind);
else
tcf_idr_cleanup(tn, index);
return -EINVAL;
}
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, index);
NL_SET_ERR_MSG_MOD(extack, "Unknown mirred option");
return -EINVAL;
}
if (!exists) {
if (!parm->ifindex && !tb[TCA_MIRRED_BLOCKID]) {
tcf_idr_cleanup(tn, index);
NL_SET_ERR_MSG_MOD(extack,
"Must specify device or block");
return -EINVAL;
}
ret = tcf_idr_create_from_flags(tn, index, est, a,
&act_mirred_ops, bind, flags);
if (ret) {
tcf_idr_cleanup(tn, index);
return ret;
}
ret = ACT_P_CREATED;
} else if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
tcf_idr_release(*a, bind);
return -EEXIST;
}
m = to_mirred(*a);
if (ret == ACT_P_CREATED)
INIT_LIST_HEAD(&m->tcfm_list);
err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
if (err < 0)
goto release_idr;
spin_lock_bh(&m->tcf_lock);
if (parm->ifindex) {
struct net_device *ndev;
ndev = dev_get_by_index(net, parm->ifindex);
if (!ndev) {
spin_unlock_bh(&m->tcf_lock);
err = -ENODEV;
goto put_chain;
}
mac_header_xmit = dev_is_mac_header_xmit(ndev);
tcf_mirred_replace_dev(m, ndev);
netdev_tracker_alloc(ndev, &m->tcfm_dev_tracker, GFP_ATOMIC);
m->tcfm_mac_header_xmit = mac_header_xmit;
m->tcfm_blockid = 0;
} else if (tb[TCA_MIRRED_BLOCKID]) {
tcf_mirred_replace_dev(m, NULL);
m->tcfm_mac_header_xmit = false;
m->tcfm_blockid = nla_get_u32(tb[TCA_MIRRED_BLOCKID]);
}
goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
m->tcfm_eaction = parm->eaction;
spin_unlock_bh(&m->tcf_lock);
if (goto_ch)
tcf_chain_put_by_act(goto_ch);
if (ret == ACT_P_CREATED) {
spin_lock(&mirred_list_lock);
list_add(&m->tcfm_list, &mirred_list);
spin_unlock(&mirred_list_lock);
}
return ret;
put_chain:
if (goto_ch)
tcf_chain_put_by_act(goto_ch);
release_idr:
tcf_idr_release(*a, bind);
return err;
}
static bool is_mirred_nested(void)
{
return unlikely(__this_cpu_read(mirred_nest_level) > 1);
}
static int tcf_mirred_forward(bool want_ingress, struct sk_buff *skb)
{
int err;
if (!want_ingress)
err = tcf_dev_queue_xmit(skb, dev_queue_xmit);
else if (is_mirred_nested())
err = netif_rx(skb);
else
err = netif_receive_skb(skb);
return err;
}
static int tcf_mirred_to_dev(struct sk_buff *skb, struct tcf_mirred *m,
struct net_device *dev,
const bool m_mac_header_xmit, int m_eaction,
int retval)
{
struct sk_buff *skb_to_send = skb;
bool want_ingress;
bool is_redirect;
bool expects_nh;
bool at_ingress;
bool dont_clone;
int mac_len;
bool at_nh;
int err;
is_redirect = tcf_mirred_is_act_redirect(m_eaction);
if (unlikely(!(dev->flags & IFF_UP)) || !netif_carrier_ok(dev)) {
net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
dev->name);
err = -ENODEV;
goto out;
}
/* we could easily avoid the clone only if called by ingress and clsact;
* since we can't easily detect the clsact caller, skip clone only for
* ingress - that covers the TC S/W datapath.
*/
at_ingress = skb_at_tc_ingress(skb);
dont_clone = skb_at_tc_ingress(skb) && is_redirect &&
tcf_mirred_can_reinsert(retval);
if (!dont_clone) {
skb_to_send = skb_clone(skb, GFP_ATOMIC);
if (!skb_to_send) {
err = -ENOMEM;
goto out;
}
}
want_ingress = tcf_mirred_act_wants_ingress(m_eaction);
/* All mirred/redirected skbs should clear previous ct info */
nf_reset_ct(skb_to_send);
if (want_ingress && !at_ingress) /* drop dst for egress -> ingress */
skb_dst_drop(skb_to_send);
expects_nh = want_ingress || !m_mac_header_xmit;
at_nh = skb->data == skb_network_header(skb);
if (at_nh != expects_nh) {
mac_len = at_ingress ? skb->mac_len :
skb_network_offset(skb);
if (expects_nh) {
/* target device/action expect data at nh */
skb_pull_rcsum(skb_to_send, mac_len);
} else {
/* target device/action expect data at mac */
skb_push_rcsum(skb_to_send, mac_len);
}
}
skb_to_send->skb_iif = skb->dev->ifindex;
skb_to_send->dev = dev;
if (is_redirect) {
if (skb == skb_to_send)
retval = TC_ACT_CONSUMED;
skb_set_redirected(skb_to_send, skb_to_send->tc_at_ingress);
err = tcf_mirred_forward(want_ingress, skb_to_send);
} else {
err = tcf_mirred_forward(want_ingress, skb_to_send);
}
if (err) {
out:
tcf_action_inc_overlimit_qstats(&m->common);
if (is_redirect)
retval = TC_ACT_SHOT;
}
return retval;
}
static int tcf_blockcast_redir(struct sk_buff *skb, struct tcf_mirred *m,
struct tcf_block *block, int m_eaction,
const u32 exception_ifindex, int retval)
{
struct net_device *dev_prev = NULL;
struct net_device *dev = NULL;
unsigned long index;
int mirred_eaction;
mirred_eaction = tcf_mirred_act_wants_ingress(m_eaction) ?
TCA_INGRESS_MIRROR : TCA_EGRESS_MIRROR;
xa_for_each(&block->ports, index, dev) {
if (index == exception_ifindex)
continue;
if (!dev_prev)
goto assign_prev;
tcf_mirred_to_dev(skb, m, dev_prev,
dev_is_mac_header_xmit(dev),
mirred_eaction, retval);
assign_prev:
dev_prev = dev;
}
if (dev_prev)
return tcf_mirred_to_dev(skb, m, dev_prev,
dev_is_mac_header_xmit(dev_prev),
m_eaction, retval);
return retval;
}
static int tcf_blockcast_mirror(struct sk_buff *skb, struct tcf_mirred *m,
struct tcf_block *block, int m_eaction,
const u32 exception_ifindex, int retval)
{
struct net_device *dev = NULL;
unsigned long index;
xa_for_each(&block->ports, index, dev) {
if (index == exception_ifindex)
continue;
tcf_mirred_to_dev(skb, m, dev,
dev_is_mac_header_xmit(dev),
m_eaction, retval);
}
return retval;
}
static int tcf_blockcast(struct sk_buff *skb, struct tcf_mirred *m,
const u32 blockid, struct tcf_result *res,
int retval)
{
const u32 exception_ifindex = skb->dev->ifindex;
struct tcf_block *block;
bool is_redirect;
int m_eaction;
m_eaction = READ_ONCE(m->tcfm_eaction);
is_redirect = tcf_mirred_is_act_redirect(m_eaction);
/* we are already under rcu protection, so can call block lookup
* directly.
*/
block = tcf_block_lookup(dev_net(skb->dev), blockid);
if (!block || xa_empty(&block->ports)) {
tcf_action_inc_overlimit_qstats(&m->common);
return retval;
}
if (is_redirect)
return tcf_blockcast_redir(skb, m, block, m_eaction,
exception_ifindex, retval);
/* If it's not redirect, it is mirror */
return tcf_blockcast_mirror(skb, m, block, m_eaction, exception_ifindex,
retval);
}
TC_INDIRECT_SCOPE int tcf_mirred_act(struct sk_buff *skb,
const struct tc_action *a,
struct tcf_result *res)
{
struct tcf_mirred *m = to_mirred(a);
int retval = READ_ONCE(m->tcf_action);
unsigned int nest_level;
bool m_mac_header_xmit;
struct net_device *dev;
int m_eaction;
u32 blockid;
nest_level = __this_cpu_inc_return(mirred_nest_level);
if (unlikely(nest_level > MIRRED_NEST_LIMIT)) {
net_warn_ratelimited("Packet exceeded mirred recursion limit on dev %s\n",
netdev_name(skb->dev));
retval = TC_ACT_SHOT;
goto dec_nest_level;
}
tcf_lastuse_update(&m->tcf_tm);
tcf_action_update_bstats(&m->common, skb);
blockid = READ_ONCE(m->tcfm_blockid);
if (blockid) {
retval = tcf_blockcast(skb, m, blockid, res, retval);
goto dec_nest_level;
}
dev = rcu_dereference_bh(m->tcfm_dev);
if (unlikely(!dev)) {
pr_notice_once("tc mirred: target device is gone\n");
tcf_action_inc_overlimit_qstats(&m->common);
goto dec_nest_level;
}
m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit);
m_eaction = READ_ONCE(m->tcfm_eaction);
retval = tcf_mirred_to_dev(skb, m, dev, m_mac_header_xmit, m_eaction,
retval);
dec_nest_level:
__this_cpu_dec(mirred_nest_level);
return retval;
}
static void tcf_stats_update(struct tc_action *a, u64 bytes, u64 packets,
u64 drops, u64 lastuse, bool hw)
{
struct tcf_mirred *m = to_mirred(a);
struct tcf_t *tm = &m->tcf_tm;
tcf_action_update_stats(a, bytes, packets, drops, hw);
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 tc_mirred opt = {
.index = m->tcf_index,
.refcnt = refcount_read(&m->tcf_refcnt) - ref,
.bindcnt = atomic_read(&m->tcf_bindcnt) - bind,
};
struct net_device *dev;
struct tcf_t t;
u32 blockid;
spin_lock_bh(&m->tcf_lock);
opt.action = m->tcf_action;
opt.eaction = m->tcfm_eaction;
dev = tcf_mirred_dev_dereference(m);
if (dev)
opt.ifindex = dev->ifindex;
if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
goto nla_put_failure;
blockid = m->tcfm_blockid;
if (blockid && nla_put_u32(skb, TCA_MIRRED_BLOCKID, blockid))
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;
spin_unlock_bh(&m->tcf_lock);
return skb->len;
nla_put_failure:
spin_unlock_bh(&m->tcf_lock);
nlmsg_trim(skb, b);
return -1;
}
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(&mirred_list_lock);
list_for_each_entry(m, &mirred_list, tcfm_list) {
spin_lock_bh(&m->tcf_lock);
if (tcf_mirred_dev_dereference(m) == dev) {
netdev_put(dev, &m->tcfm_dev_tracker);
/* Note : no rcu grace period necessary, as
* net_device are already rcu protected.
*/
RCU_INIT_POINTER(m->tcfm_dev, NULL);
} else if (m->tcfm_blockid) {
m->tcfm_blockid = 0;
}
spin_unlock_bh(&m->tcf_lock);
}
spin_unlock(&mirred_list_lock);
}
return NOTIFY_DONE;
}
static struct notifier_block mirred_device_notifier = {
.notifier_call = mirred_device_event,
};
static void tcf_mirred_dev_put(void *priv)
{
struct net_device *dev = priv;
dev_put(dev);
}
static struct net_device *
tcf_mirred_get_dev(const struct tc_action *a,
tc_action_priv_destructor *destructor)
{
struct tcf_mirred *m = to_mirred(a);
struct net_device *dev;
rcu_read_lock();
dev = rcu_dereference(m->tcfm_dev);
if (dev) {
dev_hold(dev);
*destructor = tcf_mirred_dev_put;
}
rcu_read_unlock();
return dev;
}
static size_t tcf_mirred_get_fill_size(const struct tc_action *act)
{
return nla_total_size(sizeof(struct tc_mirred));
}
static void tcf_offload_mirred_get_dev(struct flow_action_entry *entry,
const struct tc_action *act)
{
entry->dev = act->ops->get_dev(act, &entry->destructor);
if (!entry->dev)
return;
entry->destructor_priv = entry->dev;
}
static int tcf_mirred_offload_act_setup(struct tc_action *act, void *entry_data,
u32 *index_inc, bool bind,
struct netlink_ext_ack *extack)
{
if (bind) {
struct flow_action_entry *entry = entry_data;
if (is_tcf_mirred_egress_redirect(act)) {
entry->id = FLOW_ACTION_REDIRECT;
tcf_offload_mirred_get_dev(entry, act);
} else if (is_tcf_mirred_egress_mirror(act)) {
entry->id = FLOW_ACTION_MIRRED;
tcf_offload_mirred_get_dev(entry, act);
} else if (is_tcf_mirred_ingress_redirect(act)) {
entry->id = FLOW_ACTION_REDIRECT_INGRESS;
tcf_offload_mirred_get_dev(entry, act);
} else if (is_tcf_mirred_ingress_mirror(act)) {
entry->id = FLOW_ACTION_MIRRED_INGRESS;
tcf_offload_mirred_get_dev(entry, act);
} else {
NL_SET_ERR_MSG_MOD(extack, "Unsupported mirred offload");
return -EOPNOTSUPP;
}
*index_inc = 1;
} else {
struct flow_offload_action *fl_action = entry_data;
if (is_tcf_mirred_egress_redirect(act))
fl_action->id = FLOW_ACTION_REDIRECT;
else if (is_tcf_mirred_egress_mirror(act))
fl_action->id = FLOW_ACTION_MIRRED;
else if (is_tcf_mirred_ingress_redirect(act))
fl_action->id = FLOW_ACTION_REDIRECT_INGRESS;
else if (is_tcf_mirred_ingress_mirror(act))
fl_action->id = FLOW_ACTION_MIRRED_INGRESS;
else
return -EOPNOTSUPP;
}
return 0;
}
static struct tc_action_ops act_mirred_ops = {
.kind = "mirred",
.id = TCA_ID_MIRRED,
.owner = THIS_MODULE,
.act = tcf_mirred_act,
.stats_update = tcf_stats_update,
.dump = tcf_mirred_dump,
.cleanup = tcf_mirred_release,
.init = tcf_mirred_init,
.get_fill_size = tcf_mirred_get_fill_size,
.offload_act_setup = tcf_mirred_offload_act_setup,
.size = sizeof(struct tcf_mirred),
.get_dev = tcf_mirred_get_dev,
};
static __net_init int mirred_init_net(struct net *net)
{
struct tc_action_net *tn = net_generic(net, act_mirred_ops.net_id);
return tc_action_net_init(net, tn, &act_mirred_ops);
}
static void __net_exit mirred_exit_net(struct list_head *net_list)
{
tc_action_net_exit(net_list, act_mirred_ops.net_id);
}
static struct pernet_operations mirred_net_ops = {
.init = mirred_init_net,
.exit_batch = mirred_exit_net,
.id = &act_mirred_ops.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");
err = tcf_register_action(&act_mirred_ops, &mirred_net_ops);
if (err)
unregister_netdevice_notifier(&mirred_device_notifier);
return err;
}
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);