linux/net/batman-adv/multicast.c
Linus Lüssing cbebd363b2 batman-adv: Use own timer for multicast TT and TVLV updates
Instead of latching onto the OGM period, this patch introduces a worker
dedicated to multicast TT and TVLV updates.

The reasoning is, that upon roaming especially the translation table
should be updated timely to minimize connectivity issues.

With BATMAN V, the idea is to greatly increase the OGM interval to
reduce overhead. Unfortunately, right now this could lead to
a bad user experience if multicast traffic is involved.

Therefore this patch introduces a fixed 500ms update interval for
multicast TT entries and the multicast TVLV.

Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2016-10-30 11:11:35 +01:00

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/* Copyright (C) 2014-2016 B.A.T.M.A.N. contributors:
*
* Linus Lüssing
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "multicast.h"
#include "main.h"
#include <linux/atomic.h>
#include <linux/bitops.h>
#include <linux/bug.h>
#include <linux/byteorder/generic.h>
#include <linux/errno.h>
#include <linux/etherdevice.h>
#include <linux/fs.h>
#include <linux/icmpv6.h>
#include <linux/if_bridge.h>
#include <linux/if_ether.h>
#include <linux/igmp.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/kref.h>
#include <linux/list.h>
#include <linux/lockdep.h>
#include <linux/netdevice.h>
#include <linux/printk.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/seq_file.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/stddef.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/workqueue.h>
#include <net/addrconf.h>
#include <net/if_inet6.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include "hard-interface.h"
#include "hash.h"
#include "log.h"
#include "packet.h"
#include "translation-table.h"
#include "tvlv.h"
static void batadv_mcast_mla_update(struct work_struct *work);
/**
* batadv_mcast_start_timer - schedule the multicast periodic worker
* @bat_priv: the bat priv with all the soft interface information
*/
static void batadv_mcast_start_timer(struct batadv_priv *bat_priv)
{
queue_delayed_work(batadv_event_workqueue, &bat_priv->mcast.work,
msecs_to_jiffies(BATADV_MCAST_WORK_PERIOD));
}
/**
* batadv_mcast_get_bridge - get the bridge on top of the softif if it exists
* @soft_iface: netdev struct of the mesh interface
*
* If the given soft interface has a bridge on top then the refcount
* of the according net device is increased.
*
* Return: NULL if no such bridge exists. Otherwise the net device of the
* bridge.
*/
static struct net_device *batadv_mcast_get_bridge(struct net_device *soft_iface)
{
struct net_device *upper = soft_iface;
rcu_read_lock();
do {
upper = netdev_master_upper_dev_get_rcu(upper);
} while (upper && !(upper->priv_flags & IFF_EBRIDGE));
if (upper)
dev_hold(upper);
rcu_read_unlock();
return upper;
}
/**
* batadv_mcast_mla_softif_get - get softif multicast listeners
* @dev: the device to collect multicast addresses from
* @mcast_list: a list to put found addresses into
*
* Collects multicast addresses of multicast listeners residing
* on this kernel on the given soft interface, dev, in
* the given mcast_list. In general, multicast listeners provided by
* your multicast receiving applications run directly on this node.
*
* If there is a bridge interface on top of dev, collects from that one
* instead. Just like with IP addresses and routes, multicast listeners
* will(/should) register to the bridge interface instead of an
* enslaved bat0.
*
* Return: -ENOMEM on memory allocation error or the number of
* items added to the mcast_list otherwise.
*/
static int batadv_mcast_mla_softif_get(struct net_device *dev,
struct hlist_head *mcast_list)
{
struct net_device *bridge = batadv_mcast_get_bridge(dev);
struct netdev_hw_addr *mc_list_entry;
struct batadv_hw_addr *new;
int ret = 0;
netif_addr_lock_bh(bridge ? bridge : dev);
netdev_for_each_mc_addr(mc_list_entry, bridge ? bridge : dev) {
new = kmalloc(sizeof(*new), GFP_ATOMIC);
if (!new) {
ret = -ENOMEM;
break;
}
ether_addr_copy(new->addr, mc_list_entry->addr);
hlist_add_head(&new->list, mcast_list);
ret++;
}
netif_addr_unlock_bh(bridge ? bridge : dev);
if (bridge)
dev_put(bridge);
return ret;
}
/**
* batadv_mcast_mla_is_duplicate - check whether an address is in a list
* @mcast_addr: the multicast address to check
* @mcast_list: the list with multicast addresses to search in
*
* Return: true if the given address is already in the given list.
* Otherwise returns false.
*/
static bool batadv_mcast_mla_is_duplicate(u8 *mcast_addr,
struct hlist_head *mcast_list)
{
struct batadv_hw_addr *mcast_entry;
hlist_for_each_entry(mcast_entry, mcast_list, list)
if (batadv_compare_eth(mcast_entry->addr, mcast_addr))
return true;
return false;
}
/**
* batadv_mcast_mla_br_addr_cpy - copy a bridge multicast address
* @dst: destination to write to - a multicast MAC address
* @src: source to read from - a multicast IP address
*
* Converts a given multicast IPv4/IPv6 address from a bridge
* to its matching multicast MAC address and copies it into the given
* destination buffer.
*
* Caller needs to make sure the destination buffer can hold
* at least ETH_ALEN bytes.
*/
static void batadv_mcast_mla_br_addr_cpy(char *dst, const struct br_ip *src)
{
if (src->proto == htons(ETH_P_IP))
ip_eth_mc_map(src->u.ip4, dst);
#if IS_ENABLED(CONFIG_IPV6)
else if (src->proto == htons(ETH_P_IPV6))
ipv6_eth_mc_map(&src->u.ip6, dst);
#endif
else
eth_zero_addr(dst);
}
/**
* batadv_mcast_mla_bridge_get - get bridged-in multicast listeners
* @dev: a bridge slave whose bridge to collect multicast addresses from
* @mcast_list: a list to put found addresses into
*
* Collects multicast addresses of multicast listeners residing
* on foreign, non-mesh devices which we gave access to our mesh via
* a bridge on top of the given soft interface, dev, in the given
* mcast_list.
*
* Return: -ENOMEM on memory allocation error or the number of
* items added to the mcast_list otherwise.
*/
static int batadv_mcast_mla_bridge_get(struct net_device *dev,
struct hlist_head *mcast_list)
{
struct list_head bridge_mcast_list = LIST_HEAD_INIT(bridge_mcast_list);
struct br_ip_list *br_ip_entry, *tmp;
struct batadv_hw_addr *new;
u8 mcast_addr[ETH_ALEN];
int ret;
/* we don't need to detect these devices/listeners, the IGMP/MLD
* snooping code of the Linux bridge already does that for us
*/
ret = br_multicast_list_adjacent(dev, &bridge_mcast_list);
if (ret < 0)
goto out;
list_for_each_entry(br_ip_entry, &bridge_mcast_list, list) {
batadv_mcast_mla_br_addr_cpy(mcast_addr, &br_ip_entry->addr);
if (batadv_mcast_mla_is_duplicate(mcast_addr, mcast_list))
continue;
new = kmalloc(sizeof(*new), GFP_ATOMIC);
if (!new) {
ret = -ENOMEM;
break;
}
ether_addr_copy(new->addr, mcast_addr);
hlist_add_head(&new->list, mcast_list);
}
out:
list_for_each_entry_safe(br_ip_entry, tmp, &bridge_mcast_list, list) {
list_del(&br_ip_entry->list);
kfree(br_ip_entry);
}
return ret;
}
/**
* batadv_mcast_mla_list_free - free a list of multicast addresses
* @mcast_list: the list to free
*
* Removes and frees all items in the given mcast_list.
*/
static void batadv_mcast_mla_list_free(struct hlist_head *mcast_list)
{
struct batadv_hw_addr *mcast_entry;
struct hlist_node *tmp;
hlist_for_each_entry_safe(mcast_entry, tmp, mcast_list, list) {
hlist_del(&mcast_entry->list);
kfree(mcast_entry);
}
}
/**
* batadv_mcast_mla_tt_retract - clean up multicast listener announcements
* @bat_priv: the bat priv with all the soft interface information
* @mcast_list: a list of addresses which should _not_ be removed
*
* Retracts the announcement of any multicast listener from the
* translation table except the ones listed in the given mcast_list.
*
* If mcast_list is NULL then all are retracted.
*
* Do not call outside of the mcast worker! (or cancel mcast worker first)
*/
static void batadv_mcast_mla_tt_retract(struct batadv_priv *bat_priv,
struct hlist_head *mcast_list)
{
struct batadv_hw_addr *mcast_entry;
struct hlist_node *tmp;
WARN_ON(delayed_work_pending(&bat_priv->mcast.work));
hlist_for_each_entry_safe(mcast_entry, tmp, &bat_priv->mcast.mla_list,
list) {
if (mcast_list &&
batadv_mcast_mla_is_duplicate(mcast_entry->addr,
mcast_list))
continue;
batadv_tt_local_remove(bat_priv, mcast_entry->addr,
BATADV_NO_FLAGS,
"mcast TT outdated", false);
hlist_del(&mcast_entry->list);
kfree(mcast_entry);
}
}
/**
* batadv_mcast_mla_tt_add - add multicast listener announcements
* @bat_priv: the bat priv with all the soft interface information
* @mcast_list: a list of addresses which are going to get added
*
* Adds multicast listener announcements from the given mcast_list to the
* translation table if they have not been added yet.
*
* Do not call outside of the mcast worker! (or cancel mcast worker first)
*/
static void batadv_mcast_mla_tt_add(struct batadv_priv *bat_priv,
struct hlist_head *mcast_list)
{
struct batadv_hw_addr *mcast_entry;
struct hlist_node *tmp;
WARN_ON(delayed_work_pending(&bat_priv->mcast.work));
if (!mcast_list)
return;
hlist_for_each_entry_safe(mcast_entry, tmp, mcast_list, list) {
if (batadv_mcast_mla_is_duplicate(mcast_entry->addr,
&bat_priv->mcast.mla_list))
continue;
if (!batadv_tt_local_add(bat_priv->soft_iface,
mcast_entry->addr, BATADV_NO_FLAGS,
BATADV_NULL_IFINDEX, BATADV_NO_MARK))
continue;
hlist_del(&mcast_entry->list);
hlist_add_head(&mcast_entry->list, &bat_priv->mcast.mla_list);
}
}
/**
* batadv_mcast_has_bridge - check whether the soft-iface is bridged
* @bat_priv: the bat priv with all the soft interface information
*
* Checks whether there is a bridge on top of our soft interface.
*
* Return: true if there is a bridge, false otherwise.
*/
static bool batadv_mcast_has_bridge(struct batadv_priv *bat_priv)
{
struct net_device *upper = bat_priv->soft_iface;
rcu_read_lock();
do {
upper = netdev_master_upper_dev_get_rcu(upper);
} while (upper && !(upper->priv_flags & IFF_EBRIDGE));
rcu_read_unlock();
return upper;
}
/**
* batadv_mcast_querier_log - debug output regarding the querier status on link
* @bat_priv: the bat priv with all the soft interface information
* @str_proto: a string for the querier protocol (e.g. "IGMP" or "MLD")
* @old_state: the previous querier state on our link
* @new_state: the new querier state on our link
*
* Outputs debug messages to the logging facility with log level 'mcast'
* regarding changes to the querier status on the link which are relevant
* to our multicast optimizations.
*
* Usually this is about whether a querier appeared or vanished in
* our mesh or whether the querier is in the suboptimal position of being
* behind our local bridge segment: Snooping switches will directly
* forward listener reports to the querier, therefore batman-adv and
* the bridge will potentially not see these listeners - the querier is
* potentially shadowing listeners from us then.
*
* This is only interesting for nodes with a bridge on top of their
* soft interface.
*/
static void
batadv_mcast_querier_log(struct batadv_priv *bat_priv, char *str_proto,
struct batadv_mcast_querier_state *old_state,
struct batadv_mcast_querier_state *new_state)
{
if (!old_state->exists && new_state->exists)
batadv_info(bat_priv->soft_iface, "%s Querier appeared\n",
str_proto);
else if (old_state->exists && !new_state->exists)
batadv_info(bat_priv->soft_iface,
"%s Querier disappeared - multicast optimizations disabled\n",
str_proto);
else if (!bat_priv->mcast.bridged && !new_state->exists)
batadv_info(bat_priv->soft_iface,
"No %s Querier present - multicast optimizations disabled\n",
str_proto);
if (new_state->exists) {
if ((!old_state->shadowing && new_state->shadowing) ||
(!old_state->exists && new_state->shadowing))
batadv_dbg(BATADV_DBG_MCAST, bat_priv,
"%s Querier is behind our bridged segment: Might shadow listeners\n",
str_proto);
else if (old_state->shadowing && !new_state->shadowing)
batadv_dbg(BATADV_DBG_MCAST, bat_priv,
"%s Querier is not behind our bridged segment\n",
str_proto);
}
}
/**
* batadv_mcast_bridge_log - debug output for topology changes in bridged setups
* @bat_priv: the bat priv with all the soft interface information
* @bridged: a flag about whether the soft interface is currently bridged or not
* @querier_ipv4: (maybe) new status of a potential, selected IGMP querier
* @querier_ipv6: (maybe) new status of a potential, selected MLD querier
*
* If no bridges are ever used on this node, then this function does nothing.
*
* Otherwise this function outputs debug information to the 'mcast' log level
* which might be relevant to our multicast optimizations.
*
* More precisely, it outputs information when a bridge interface is added or
* removed from a soft interface. And when a bridge is present, it further
* outputs information about the querier state which is relevant for the
* multicast flags this node is going to set.
*/
static void
batadv_mcast_bridge_log(struct batadv_priv *bat_priv, bool bridged,
struct batadv_mcast_querier_state *querier_ipv4,
struct batadv_mcast_querier_state *querier_ipv6)
{
if (!bat_priv->mcast.bridged && bridged)
batadv_dbg(BATADV_DBG_MCAST, bat_priv,
"Bridge added: Setting Unsnoopables(U)-flag\n");
else if (bat_priv->mcast.bridged && !bridged)
batadv_dbg(BATADV_DBG_MCAST, bat_priv,
"Bridge removed: Unsetting Unsnoopables(U)-flag\n");
if (bridged) {
batadv_mcast_querier_log(bat_priv, "IGMP",
&bat_priv->mcast.querier_ipv4,
querier_ipv4);
batadv_mcast_querier_log(bat_priv, "MLD",
&bat_priv->mcast.querier_ipv6,
querier_ipv6);
}
}
/**
* batadv_mcast_flags_logs - output debug information about mcast flag changes
* @bat_priv: the bat priv with all the soft interface information
* @flags: flags indicating the new multicast state
*
* Whenever the multicast flags this nodes announces changes (@mcast_flags vs.
* bat_priv->mcast.flags), this notifies userspace via the 'mcast' log level.
*/
static void batadv_mcast_flags_log(struct batadv_priv *bat_priv, u8 flags)
{
u8 old_flags = bat_priv->mcast.flags;
char str_old_flags[] = "[...]";
sprintf(str_old_flags, "[%c%c%c]",
(old_flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES) ? 'U' : '.',
(old_flags & BATADV_MCAST_WANT_ALL_IPV4) ? '4' : '.',
(old_flags & BATADV_MCAST_WANT_ALL_IPV6) ? '6' : '.');
batadv_dbg(BATADV_DBG_MCAST, bat_priv,
"Changing multicast flags from '%s' to '[%c%c%c]'\n",
bat_priv->mcast.enabled ? str_old_flags : "<undefined>",
(flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES) ? 'U' : '.',
(flags & BATADV_MCAST_WANT_ALL_IPV4) ? '4' : '.',
(flags & BATADV_MCAST_WANT_ALL_IPV6) ? '6' : '.');
}
/**
* batadv_mcast_mla_tvlv_update - update multicast tvlv
* @bat_priv: the bat priv with all the soft interface information
*
* Updates the own multicast tvlv with our current multicast related settings,
* capabilities and inabilities.
*
* Return: false if we want all IPv4 && IPv6 multicast traffic and true
* otherwise.
*/
static bool batadv_mcast_mla_tvlv_update(struct batadv_priv *bat_priv)
{
struct batadv_tvlv_mcast_data mcast_data;
struct batadv_mcast_querier_state querier4 = {false, false};
struct batadv_mcast_querier_state querier6 = {false, false};
struct net_device *dev = bat_priv->soft_iface;
bool bridged;
mcast_data.flags = BATADV_NO_FLAGS;
memset(mcast_data.reserved, 0, sizeof(mcast_data.reserved));
bridged = batadv_mcast_has_bridge(bat_priv);
if (!bridged)
goto update;
#if !IS_ENABLED(CONFIG_BRIDGE_IGMP_SNOOPING)
pr_warn_once("No bridge IGMP snooping compiled - multicast optimizations disabled\n");
#endif
querier4.exists = br_multicast_has_querier_anywhere(dev, ETH_P_IP);
querier4.shadowing = br_multicast_has_querier_adjacent(dev, ETH_P_IP);
querier6.exists = br_multicast_has_querier_anywhere(dev, ETH_P_IPV6);
querier6.shadowing = br_multicast_has_querier_adjacent(dev, ETH_P_IPV6);
mcast_data.flags |= BATADV_MCAST_WANT_ALL_UNSNOOPABLES;
/* 1) If no querier exists at all, then multicast listeners on
* our local TT clients behind the bridge will keep silent.
* 2) If the selected querier is on one of our local TT clients,
* behind the bridge, then this querier might shadow multicast
* listeners on our local TT clients, behind this bridge.
*
* In both cases, we will signalize other batman nodes that
* we need all multicast traffic of the according protocol.
*/
if (!querier4.exists || querier4.shadowing)
mcast_data.flags |= BATADV_MCAST_WANT_ALL_IPV4;
if (!querier6.exists || querier6.shadowing)
mcast_data.flags |= BATADV_MCAST_WANT_ALL_IPV6;
update:
batadv_mcast_bridge_log(bat_priv, bridged, &querier4, &querier6);
bat_priv->mcast.querier_ipv4.exists = querier4.exists;
bat_priv->mcast.querier_ipv4.shadowing = querier4.shadowing;
bat_priv->mcast.querier_ipv6.exists = querier6.exists;
bat_priv->mcast.querier_ipv6.shadowing = querier6.shadowing;
bat_priv->mcast.bridged = bridged;
if (!bat_priv->mcast.enabled ||
mcast_data.flags != bat_priv->mcast.flags) {
batadv_mcast_flags_log(bat_priv, mcast_data.flags);
batadv_tvlv_container_register(bat_priv, BATADV_TVLV_MCAST, 2,
&mcast_data, sizeof(mcast_data));
bat_priv->mcast.flags = mcast_data.flags;
bat_priv->mcast.enabled = true;
}
return !(mcast_data.flags &
(BATADV_MCAST_WANT_ALL_IPV4 | BATADV_MCAST_WANT_ALL_IPV6));
}
/**
* __batadv_mcast_mla_update - update the own MLAs
* @bat_priv: the bat priv with all the soft interface information
*
* Updates the own multicast listener announcements in the translation
* table as well as the own, announced multicast tvlv container.
*
* Note that non-conflicting reads and writes to bat_priv->mcast.mla_list
* in batadv_mcast_mla_tt_retract() and batadv_mcast_mla_tt_add() are
* ensured by the non-parallel execution of the worker this function
* belongs to.
*/
static void __batadv_mcast_mla_update(struct batadv_priv *bat_priv)
{
struct net_device *soft_iface = bat_priv->soft_iface;
struct hlist_head mcast_list = HLIST_HEAD_INIT;
int ret;
if (!batadv_mcast_mla_tvlv_update(bat_priv))
goto update;
ret = batadv_mcast_mla_softif_get(soft_iface, &mcast_list);
if (ret < 0)
goto out;
ret = batadv_mcast_mla_bridge_get(soft_iface, &mcast_list);
if (ret < 0)
goto out;
update:
batadv_mcast_mla_tt_retract(bat_priv, &mcast_list);
batadv_mcast_mla_tt_add(bat_priv, &mcast_list);
out:
batadv_mcast_mla_list_free(&mcast_list);
}
/**
* batadv_mcast_mla_update - update the own MLAs
* @work: kernel work struct
*
* Updates the own multicast listener announcements in the translation
* table as well as the own, announced multicast tvlv container.
*
* In the end, reschedules the work timer.
*/
static void batadv_mcast_mla_update(struct work_struct *work)
{
struct delayed_work *delayed_work;
struct batadv_priv_mcast *priv_mcast;
struct batadv_priv *bat_priv;
delayed_work = to_delayed_work(work);
priv_mcast = container_of(delayed_work, struct batadv_priv_mcast, work);
bat_priv = container_of(priv_mcast, struct batadv_priv, mcast);
__batadv_mcast_mla_update(bat_priv);
batadv_mcast_start_timer(bat_priv);
}
/**
* batadv_mcast_is_report_ipv4 -check for IGMP reports
* @skb: the ethernet frame destined for the mesh
*
* This call might reallocate skb data.
*
* Checks whether the given frame is a valid IGMP report.
*
* Return: If so then true, otherwise false.
*/
static bool batadv_mcast_is_report_ipv4(struct sk_buff *skb)
{
if (ip_mc_check_igmp(skb, NULL) < 0)
return false;
switch (igmp_hdr(skb)->type) {
case IGMP_HOST_MEMBERSHIP_REPORT:
case IGMPV2_HOST_MEMBERSHIP_REPORT:
case IGMPV3_HOST_MEMBERSHIP_REPORT:
return true;
}
return false;
}
/**
* batadv_mcast_forw_mode_check_ipv4 - check for optimized forwarding potential
* @bat_priv: the bat priv with all the soft interface information
* @skb: the IPv4 packet to check
* @is_unsnoopable: stores whether the destination is snoopable
*
* Checks whether the given IPv4 packet has the potential to be forwarded with a
* mode more optimal than classic flooding.
*
* Return: If so then 0. Otherwise -EINVAL or -ENOMEM in case of memory
* allocation failure.
*/
static int batadv_mcast_forw_mode_check_ipv4(struct batadv_priv *bat_priv,
struct sk_buff *skb,
bool *is_unsnoopable)
{
struct iphdr *iphdr;
/* We might fail due to out-of-memory -> drop it */
if (!pskb_may_pull(skb, sizeof(struct ethhdr) + sizeof(*iphdr)))
return -ENOMEM;
if (batadv_mcast_is_report_ipv4(skb))
return -EINVAL;
iphdr = ip_hdr(skb);
/* TODO: Implement Multicast Router Discovery (RFC4286),
* then allow scope > link local, too
*/
if (!ipv4_is_local_multicast(iphdr->daddr))
return -EINVAL;
/* link-local multicast listeners behind a bridge are
* not snoopable (see RFC4541, section 2.1.2.2)
*/
*is_unsnoopable = true;
return 0;
}
#if IS_ENABLED(CONFIG_IPV6)
/**
* batadv_mcast_is_report_ipv6 - check for MLD reports
* @skb: the ethernet frame destined for the mesh
*
* This call might reallocate skb data.
*
* Checks whether the given frame is a valid MLD report.
*
* Return: If so then true, otherwise false.
*/
static bool batadv_mcast_is_report_ipv6(struct sk_buff *skb)
{
if (ipv6_mc_check_mld(skb, NULL) < 0)
return false;
switch (icmp6_hdr(skb)->icmp6_type) {
case ICMPV6_MGM_REPORT:
case ICMPV6_MLD2_REPORT:
return true;
}
return false;
}
/**
* batadv_mcast_forw_mode_check_ipv6 - check for optimized forwarding potential
* @bat_priv: the bat priv with all the soft interface information
* @skb: the IPv6 packet to check
* @is_unsnoopable: stores whether the destination is snoopable
*
* Checks whether the given IPv6 packet has the potential to be forwarded with a
* mode more optimal than classic flooding.
*
* Return: If so then 0. Otherwise -EINVAL is or -ENOMEM if we are out of memory
*/
static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv,
struct sk_buff *skb,
bool *is_unsnoopable)
{
struct ipv6hdr *ip6hdr;
/* We might fail due to out-of-memory -> drop it */
if (!pskb_may_pull(skb, sizeof(struct ethhdr) + sizeof(*ip6hdr)))
return -ENOMEM;
if (batadv_mcast_is_report_ipv6(skb))
return -EINVAL;
ip6hdr = ipv6_hdr(skb);
/* TODO: Implement Multicast Router Discovery (RFC4286),
* then allow scope > link local, too
*/
if (IPV6_ADDR_MC_SCOPE(&ip6hdr->daddr) != IPV6_ADDR_SCOPE_LINKLOCAL)
return -EINVAL;
/* link-local-all-nodes multicast listeners behind a bridge are
* not snoopable (see RFC4541, section 3, paragraph 3)
*/
if (ipv6_addr_is_ll_all_nodes(&ip6hdr->daddr))
*is_unsnoopable = true;
return 0;
}
#endif
/**
* batadv_mcast_forw_mode_check - check for optimized forwarding potential
* @bat_priv: the bat priv with all the soft interface information
* @skb: the multicast frame to check
* @is_unsnoopable: stores whether the destination is snoopable
*
* Checks whether the given multicast ethernet frame has the potential to be
* forwarded with a mode more optimal than classic flooding.
*
* Return: If so then 0. Otherwise -EINVAL is or -ENOMEM if we are out of memory
*/
static int batadv_mcast_forw_mode_check(struct batadv_priv *bat_priv,
struct sk_buff *skb,
bool *is_unsnoopable)
{
struct ethhdr *ethhdr = eth_hdr(skb);
if (!atomic_read(&bat_priv->multicast_mode))
return -EINVAL;
if (atomic_read(&bat_priv->mcast.num_disabled))
return -EINVAL;
switch (ntohs(ethhdr->h_proto)) {
case ETH_P_IP:
return batadv_mcast_forw_mode_check_ipv4(bat_priv, skb,
is_unsnoopable);
#if IS_ENABLED(CONFIG_IPV6)
case ETH_P_IPV6:
return batadv_mcast_forw_mode_check_ipv6(bat_priv, skb,
is_unsnoopable);
#endif
default:
return -EINVAL;
}
}
/**
* batadv_mcast_forw_want_all_ip_count - count nodes with unspecific mcast
* interest
* @bat_priv: the bat priv with all the soft interface information
* @ethhdr: ethernet header of a packet
*
* Return: the number of nodes which want all IPv4 multicast traffic if the
* given ethhdr is from an IPv4 packet or the number of nodes which want all
* IPv6 traffic if it matches an IPv6 packet.
*/
static int batadv_mcast_forw_want_all_ip_count(struct batadv_priv *bat_priv,
struct ethhdr *ethhdr)
{
switch (ntohs(ethhdr->h_proto)) {
case ETH_P_IP:
return atomic_read(&bat_priv->mcast.num_want_all_ipv4);
case ETH_P_IPV6:
return atomic_read(&bat_priv->mcast.num_want_all_ipv6);
default:
/* we shouldn't be here... */
return 0;
}
}
/**
* batadv_mcast_forw_tt_node_get - get a multicast tt node
* @bat_priv: the bat priv with all the soft interface information
* @ethhdr: the ether header containing the multicast destination
*
* Return: an orig_node matching the multicast address provided by ethhdr
* via a translation table lookup. This increases the returned nodes refcount.
*/
static struct batadv_orig_node *
batadv_mcast_forw_tt_node_get(struct batadv_priv *bat_priv,
struct ethhdr *ethhdr)
{
return batadv_transtable_search(bat_priv, ethhdr->h_source,
ethhdr->h_dest, BATADV_NO_FLAGS);
}
/**
* batadv_mcast_forw_ipv4_node_get - get a node with an ipv4 flag
* @bat_priv: the bat priv with all the soft interface information
*
* Return: an orig_node which has the BATADV_MCAST_WANT_ALL_IPV4 flag set and
* increases its refcount.
*/
static struct batadv_orig_node *
batadv_mcast_forw_ipv4_node_get(struct batadv_priv *bat_priv)
{
struct batadv_orig_node *tmp_orig_node, *orig_node = NULL;
rcu_read_lock();
hlist_for_each_entry_rcu(tmp_orig_node,
&bat_priv->mcast.want_all_ipv4_list,
mcast_want_all_ipv4_node) {
if (!kref_get_unless_zero(&tmp_orig_node->refcount))
continue;
orig_node = tmp_orig_node;
break;
}
rcu_read_unlock();
return orig_node;
}
/**
* batadv_mcast_forw_ipv6_node_get - get a node with an ipv6 flag
* @bat_priv: the bat priv with all the soft interface information
*
* Return: an orig_node which has the BATADV_MCAST_WANT_ALL_IPV6 flag set
* and increases its refcount.
*/
static struct batadv_orig_node *
batadv_mcast_forw_ipv6_node_get(struct batadv_priv *bat_priv)
{
struct batadv_orig_node *tmp_orig_node, *orig_node = NULL;
rcu_read_lock();
hlist_for_each_entry_rcu(tmp_orig_node,
&bat_priv->mcast.want_all_ipv6_list,
mcast_want_all_ipv6_node) {
if (!kref_get_unless_zero(&tmp_orig_node->refcount))
continue;
orig_node = tmp_orig_node;
break;
}
rcu_read_unlock();
return orig_node;
}
/**
* batadv_mcast_forw_ip_node_get - get a node with an ipv4/ipv6 flag
* @bat_priv: the bat priv with all the soft interface information
* @ethhdr: an ethernet header to determine the protocol family from
*
* Return: an orig_node which has the BATADV_MCAST_WANT_ALL_IPV4 or
* BATADV_MCAST_WANT_ALL_IPV6 flag, depending on the provided ethhdr, set and
* increases its refcount.
*/
static struct batadv_orig_node *
batadv_mcast_forw_ip_node_get(struct batadv_priv *bat_priv,
struct ethhdr *ethhdr)
{
switch (ntohs(ethhdr->h_proto)) {
case ETH_P_IP:
return batadv_mcast_forw_ipv4_node_get(bat_priv);
case ETH_P_IPV6:
return batadv_mcast_forw_ipv6_node_get(bat_priv);
default:
/* we shouldn't be here... */
return NULL;
}
}
/**
* batadv_mcast_forw_unsnoop_node_get - get a node with an unsnoopable flag
* @bat_priv: the bat priv with all the soft interface information
*
* Return: an orig_node which has the BATADV_MCAST_WANT_ALL_UNSNOOPABLES flag
* set and increases its refcount.
*/
static struct batadv_orig_node *
batadv_mcast_forw_unsnoop_node_get(struct batadv_priv *bat_priv)
{
struct batadv_orig_node *tmp_orig_node, *orig_node = NULL;
rcu_read_lock();
hlist_for_each_entry_rcu(tmp_orig_node,
&bat_priv->mcast.want_all_unsnoopables_list,
mcast_want_all_unsnoopables_node) {
if (!kref_get_unless_zero(&tmp_orig_node->refcount))
continue;
orig_node = tmp_orig_node;
break;
}
rcu_read_unlock();
return orig_node;
}
/**
* batadv_mcast_forw_mode - check on how to forward a multicast packet
* @bat_priv: the bat priv with all the soft interface information
* @skb: The multicast packet to check
* @orig: an originator to be set to forward the skb to
*
* Return: the forwarding mode as enum batadv_forw_mode and in case of
* BATADV_FORW_SINGLE set the orig to the single originator the skb
* should be forwarded to.
*/
enum batadv_forw_mode
batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb,
struct batadv_orig_node **orig)
{
int ret, tt_count, ip_count, unsnoop_count, total_count;
bool is_unsnoopable = false;
struct ethhdr *ethhdr;
ret = batadv_mcast_forw_mode_check(bat_priv, skb, &is_unsnoopable);
if (ret == -ENOMEM)
return BATADV_FORW_NONE;
else if (ret < 0)
return BATADV_FORW_ALL;
ethhdr = eth_hdr(skb);
tt_count = batadv_tt_global_hash_count(bat_priv, ethhdr->h_dest,
BATADV_NO_FLAGS);
ip_count = batadv_mcast_forw_want_all_ip_count(bat_priv, ethhdr);
unsnoop_count = !is_unsnoopable ? 0 :
atomic_read(&bat_priv->mcast.num_want_all_unsnoopables);
total_count = tt_count + ip_count + unsnoop_count;
switch (total_count) {
case 1:
if (tt_count)
*orig = batadv_mcast_forw_tt_node_get(bat_priv, ethhdr);
else if (ip_count)
*orig = batadv_mcast_forw_ip_node_get(bat_priv, ethhdr);
else if (unsnoop_count)
*orig = batadv_mcast_forw_unsnoop_node_get(bat_priv);
if (*orig)
return BATADV_FORW_SINGLE;
/* fall through */
case 0:
return BATADV_FORW_NONE;
default:
return BATADV_FORW_ALL;
}
}
/**
* batadv_mcast_want_unsnoop_update - update unsnoop counter and list
* @bat_priv: the bat priv with all the soft interface information
* @orig: the orig_node which multicast state might have changed of
* @mcast_flags: flags indicating the new multicast state
*
* If the BATADV_MCAST_WANT_ALL_UNSNOOPABLES flag of this originator,
* orig, has toggled then this method updates counter and list accordingly.
*
* Caller needs to hold orig->mcast_handler_lock.
*/
static void batadv_mcast_want_unsnoop_update(struct batadv_priv *bat_priv,
struct batadv_orig_node *orig,
u8 mcast_flags)
{
struct hlist_node *node = &orig->mcast_want_all_unsnoopables_node;
struct hlist_head *head = &bat_priv->mcast.want_all_unsnoopables_list;
lockdep_assert_held(&orig->mcast_handler_lock);
/* switched from flag unset to set */
if (mcast_flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES &&
!(orig->mcast_flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES)) {
atomic_inc(&bat_priv->mcast.num_want_all_unsnoopables);
spin_lock_bh(&bat_priv->mcast.want_lists_lock);
/* flag checks above + mcast_handler_lock prevents this */
WARN_ON(!hlist_unhashed(node));
hlist_add_head_rcu(node, head);
spin_unlock_bh(&bat_priv->mcast.want_lists_lock);
/* switched from flag set to unset */
} else if (!(mcast_flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES) &&
orig->mcast_flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES) {
atomic_dec(&bat_priv->mcast.num_want_all_unsnoopables);
spin_lock_bh(&bat_priv->mcast.want_lists_lock);
/* flag checks above + mcast_handler_lock prevents this */
WARN_ON(hlist_unhashed(node));
hlist_del_init_rcu(node);
spin_unlock_bh(&bat_priv->mcast.want_lists_lock);
}
}
/**
* batadv_mcast_want_ipv4_update - update want-all-ipv4 counter and list
* @bat_priv: the bat priv with all the soft interface information
* @orig: the orig_node which multicast state might have changed of
* @mcast_flags: flags indicating the new multicast state
*
* If the BATADV_MCAST_WANT_ALL_IPV4 flag of this originator, orig, has
* toggled then this method updates counter and list accordingly.
*
* Caller needs to hold orig->mcast_handler_lock.
*/
static void batadv_mcast_want_ipv4_update(struct batadv_priv *bat_priv,
struct batadv_orig_node *orig,
u8 mcast_flags)
{
struct hlist_node *node = &orig->mcast_want_all_ipv4_node;
struct hlist_head *head = &bat_priv->mcast.want_all_ipv4_list;
lockdep_assert_held(&orig->mcast_handler_lock);
/* switched from flag unset to set */
if (mcast_flags & BATADV_MCAST_WANT_ALL_IPV4 &&
!(orig->mcast_flags & BATADV_MCAST_WANT_ALL_IPV4)) {
atomic_inc(&bat_priv->mcast.num_want_all_ipv4);
spin_lock_bh(&bat_priv->mcast.want_lists_lock);
/* flag checks above + mcast_handler_lock prevents this */
WARN_ON(!hlist_unhashed(node));
hlist_add_head_rcu(node, head);
spin_unlock_bh(&bat_priv->mcast.want_lists_lock);
/* switched from flag set to unset */
} else if (!(mcast_flags & BATADV_MCAST_WANT_ALL_IPV4) &&
orig->mcast_flags & BATADV_MCAST_WANT_ALL_IPV4) {
atomic_dec(&bat_priv->mcast.num_want_all_ipv4);
spin_lock_bh(&bat_priv->mcast.want_lists_lock);
/* flag checks above + mcast_handler_lock prevents this */
WARN_ON(hlist_unhashed(node));
hlist_del_init_rcu(node);
spin_unlock_bh(&bat_priv->mcast.want_lists_lock);
}
}
/**
* batadv_mcast_want_ipv6_update - update want-all-ipv6 counter and list
* @bat_priv: the bat priv with all the soft interface information
* @orig: the orig_node which multicast state might have changed of
* @mcast_flags: flags indicating the new multicast state
*
* If the BATADV_MCAST_WANT_ALL_IPV6 flag of this originator, orig, has
* toggled then this method updates counter and list accordingly.
*
* Caller needs to hold orig->mcast_handler_lock.
*/
static void batadv_mcast_want_ipv6_update(struct batadv_priv *bat_priv,
struct batadv_orig_node *orig,
u8 mcast_flags)
{
struct hlist_node *node = &orig->mcast_want_all_ipv6_node;
struct hlist_head *head = &bat_priv->mcast.want_all_ipv6_list;
lockdep_assert_held(&orig->mcast_handler_lock);
/* switched from flag unset to set */
if (mcast_flags & BATADV_MCAST_WANT_ALL_IPV6 &&
!(orig->mcast_flags & BATADV_MCAST_WANT_ALL_IPV6)) {
atomic_inc(&bat_priv->mcast.num_want_all_ipv6);
spin_lock_bh(&bat_priv->mcast.want_lists_lock);
/* flag checks above + mcast_handler_lock prevents this */
WARN_ON(!hlist_unhashed(node));
hlist_add_head_rcu(node, head);
spin_unlock_bh(&bat_priv->mcast.want_lists_lock);
/* switched from flag set to unset */
} else if (!(mcast_flags & BATADV_MCAST_WANT_ALL_IPV6) &&
orig->mcast_flags & BATADV_MCAST_WANT_ALL_IPV6) {
atomic_dec(&bat_priv->mcast.num_want_all_ipv6);
spin_lock_bh(&bat_priv->mcast.want_lists_lock);
/* flag checks above + mcast_handler_lock prevents this */
WARN_ON(hlist_unhashed(node));
hlist_del_init_rcu(node);
spin_unlock_bh(&bat_priv->mcast.want_lists_lock);
}
}
/**
* batadv_mcast_tvlv_ogm_handler - process incoming multicast tvlv container
* @bat_priv: the bat priv with all the soft interface information
* @orig: the orig_node of the ogm
* @flags: flags indicating the tvlv state (see batadv_tvlv_handler_flags)
* @tvlv_value: tvlv buffer containing the multicast data
* @tvlv_value_len: tvlv buffer length
*/
static void batadv_mcast_tvlv_ogm_handler(struct batadv_priv *bat_priv,
struct batadv_orig_node *orig,
u8 flags,
void *tvlv_value,
u16 tvlv_value_len)
{
bool orig_mcast_enabled = !(flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND);
u8 mcast_flags = BATADV_NO_FLAGS;
bool orig_initialized;
if (orig_mcast_enabled && tvlv_value &&
(tvlv_value_len >= sizeof(mcast_flags)))
mcast_flags = *(u8 *)tvlv_value;
spin_lock_bh(&orig->mcast_handler_lock);
orig_initialized = test_bit(BATADV_ORIG_CAPA_HAS_MCAST,
&orig->capa_initialized);
/* If mcast support is turned on decrease the disabled mcast node
* counter only if we had increased it for this node before. If this
* is a completely new orig_node no need to decrease the counter.
*/
if (orig_mcast_enabled &&
!test_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capabilities)) {
if (orig_initialized)
atomic_dec(&bat_priv->mcast.num_disabled);
set_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capabilities);
/* If mcast support is being switched off or if this is an initial
* OGM without mcast support then increase the disabled mcast
* node counter.
*/
} else if (!orig_mcast_enabled &&
(test_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capabilities) ||
!orig_initialized)) {
atomic_inc(&bat_priv->mcast.num_disabled);
clear_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capabilities);
}
set_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capa_initialized);
batadv_mcast_want_unsnoop_update(bat_priv, orig, mcast_flags);
batadv_mcast_want_ipv4_update(bat_priv, orig, mcast_flags);
batadv_mcast_want_ipv6_update(bat_priv, orig, mcast_flags);
orig->mcast_flags = mcast_flags;
spin_unlock_bh(&orig->mcast_handler_lock);
}
/**
* batadv_mcast_init - initialize the multicast optimizations structures
* @bat_priv: the bat priv with all the soft interface information
*/
void batadv_mcast_init(struct batadv_priv *bat_priv)
{
batadv_tvlv_handler_register(bat_priv, batadv_mcast_tvlv_ogm_handler,
NULL, BATADV_TVLV_MCAST, 2,
BATADV_TVLV_HANDLER_OGM_CIFNOTFND);
INIT_DELAYED_WORK(&bat_priv->mcast.work, batadv_mcast_mla_update);
batadv_mcast_start_timer(bat_priv);
}
#ifdef CONFIG_BATMAN_ADV_DEBUGFS
/**
* batadv_mcast_flags_print_header - print own mcast flags to debugfs table
* @bat_priv: the bat priv with all the soft interface information
* @seq: debugfs table seq_file struct
*
* Prints our own multicast flags including a more specific reason why
* they are set, that is prints the bridge and querier state too, to
* the debugfs table specified via @seq.
*/
static void batadv_mcast_flags_print_header(struct batadv_priv *bat_priv,
struct seq_file *seq)
{
u8 flags = bat_priv->mcast.flags;
char querier4, querier6, shadowing4, shadowing6;
bool bridged = bat_priv->mcast.bridged;
if (bridged) {
querier4 = bat_priv->mcast.querier_ipv4.exists ? '.' : '4';
querier6 = bat_priv->mcast.querier_ipv6.exists ? '.' : '6';
shadowing4 = bat_priv->mcast.querier_ipv4.shadowing ? '4' : '.';
shadowing6 = bat_priv->mcast.querier_ipv6.shadowing ? '6' : '.';
} else {
querier4 = '?';
querier6 = '?';
shadowing4 = '?';
shadowing6 = '?';
}
seq_printf(seq, "Multicast flags (own flags: [%c%c%c])\n",
(flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES) ? 'U' : '.',
(flags & BATADV_MCAST_WANT_ALL_IPV4) ? '4' : '.',
(flags & BATADV_MCAST_WANT_ALL_IPV6) ? '6' : '.');
seq_printf(seq, "* Bridged [U]\t\t\t\t%c\n", bridged ? 'U' : '.');
seq_printf(seq, "* No IGMP/MLD Querier [4/6]:\t\t%c/%c\n",
querier4, querier6);
seq_printf(seq, "* Shadowing IGMP/MLD Querier [4/6]:\t%c/%c\n",
shadowing4, shadowing6);
seq_puts(seq, "-------------------------------------------\n");
seq_printf(seq, " %-10s %s\n", "Originator", "Flags");
}
/**
* batadv_mcast_flags_seq_print_text - print the mcast flags of other nodes
* @seq: seq file to print on
* @offset: not used
*
* This prints a table of (primary) originators and their according
* multicast flags, including (in the header) our own.
*
* Return: always 0
*/
int batadv_mcast_flags_seq_print_text(struct seq_file *seq, void *offset)
{
struct net_device *net_dev = (struct net_device *)seq->private;
struct batadv_priv *bat_priv = netdev_priv(net_dev);
struct batadv_hard_iface *primary_if;
struct batadv_hashtable *hash = bat_priv->orig_hash;
struct batadv_orig_node *orig_node;
struct hlist_head *head;
u8 flags;
u32 i;
primary_if = batadv_seq_print_text_primary_if_get(seq);
if (!primary_if)
return 0;
batadv_mcast_flags_print_header(bat_priv, seq);
for (i = 0; i < hash->size; i++) {
head = &hash->table[i];
rcu_read_lock();
hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
if (!test_bit(BATADV_ORIG_CAPA_HAS_MCAST,
&orig_node->capa_initialized))
continue;
if (!test_bit(BATADV_ORIG_CAPA_HAS_MCAST,
&orig_node->capabilities)) {
seq_printf(seq, "%pM -\n", orig_node->orig);
continue;
}
flags = orig_node->mcast_flags;
seq_printf(seq, "%pM [%c%c%c]\n", orig_node->orig,
(flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES)
? 'U' : '.',
(flags & BATADV_MCAST_WANT_ALL_IPV4)
? '4' : '.',
(flags & BATADV_MCAST_WANT_ALL_IPV6)
? '6' : '.');
}
rcu_read_unlock();
}
batadv_hardif_put(primary_if);
return 0;
}
#endif
/**
* batadv_mcast_free - free the multicast optimizations structures
* @bat_priv: the bat priv with all the soft interface information
*/
void batadv_mcast_free(struct batadv_priv *bat_priv)
{
cancel_delayed_work_sync(&bat_priv->mcast.work);
batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_MCAST, 2);
batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_MCAST, 2);
/* safely calling outside of worker, as worker was canceled above */
batadv_mcast_mla_tt_retract(bat_priv, NULL);
}
/**
* batadv_mcast_purge_orig - reset originator global mcast state modifications
* @orig: the originator which is going to get purged
*/
void batadv_mcast_purge_orig(struct batadv_orig_node *orig)
{
struct batadv_priv *bat_priv = orig->bat_priv;
spin_lock_bh(&orig->mcast_handler_lock);
if (!test_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capabilities) &&
test_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capa_initialized))
atomic_dec(&bat_priv->mcast.num_disabled);
batadv_mcast_want_unsnoop_update(bat_priv, orig, BATADV_NO_FLAGS);
batadv_mcast_want_ipv4_update(bat_priv, orig, BATADV_NO_FLAGS);
batadv_mcast_want_ipv6_update(bat_priv, orig, BATADV_NO_FLAGS);
spin_unlock_bh(&orig->mcast_handler_lock);
}