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multicast.c
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multicast.c
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/* Copyright (C) 2014-2017 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");
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;
}
/**
* 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;
}
/**
* 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);
case ETH_P_IPV6:
if (!IS_ENABLED(CONFIG_IPV6))
return -EINVAL;
return batadv_mcast_forw_mode_check_ipv6(bat_priv, skb,
is_unsnoopable);
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);