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batman-adv: mcast: collect softif listeners from IP lists instead
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Instead of collecting multicast MAC addresses from the netdev hw mc
list collect a node's multicast listeners from the IP lists and convert
those to MAC addresses.

This allows to exclude addresses of specific scope later. On a
multicast MAC address the IP destination scope is not visible anymore.

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>
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Linus Lüssing authored and Simon Wunderlich committed Jun 27, 2019
1 parent 6bc4544 commit 5c50680
Showing 1 changed file with 143 additions and 49 deletions.
192 changes: 143 additions & 49 deletions net/batman-adv/multicast.c
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@
#include <linux/igmp.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/inetdevice.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/jiffies.h>
Expand Down Expand Up @@ -172,70 +173,129 @@ static struct net_device *batadv_mcast_get_bridge(struct net_device *soft_iface)
}

/**
* batadv_mcast_addr_is_ipv4() - check if multicast MAC is IPv4
* @addr: the MAC address to check
* 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 MAC address is one reserved for IPv4 multicast, false
* otherwise.
* Return: true if the given address is already in the given list.
* Otherwise returns false.
*/
static bool batadv_mcast_addr_is_ipv4(const u8 *addr)
static bool batadv_mcast_mla_is_duplicate(u8 *mcast_addr,
struct hlist_head *mcast_list)
{
static const u8 prefix[] = {0x01, 0x00, 0x5E};
struct batadv_hw_addr *mcast_entry;

return memcmp(prefix, addr, sizeof(prefix)) == 0;
hlist_for_each_entry(mcast_entry, mcast_list, list)
if (batadv_compare_eth(mcast_entry->addr, mcast_addr))
return true;

return false;
}

/**
* batadv_mcast_addr_is_ipv6() - check if multicast MAC is IPv6
* @addr: the MAC address to check
* batadv_mcast_mla_softif_get_ipv4() - get softif IPv4 multicast listeners
* @dev: the device to collect multicast addresses from
* @mcast_list: a list to put found addresses into
* @flags: flags indicating the new multicast state
*
* Return: True, if MAC address is one reserved for IPv6 multicast, false
* otherwise.
* Collects multicast addresses of IPv4 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.
*
* Return: -ENOMEM on memory allocation error or the number of
* items added to the mcast_list otherwise.
*/
static bool batadv_mcast_addr_is_ipv6(const u8 *addr)
static int
batadv_mcast_mla_softif_get_ipv4(struct net_device *dev,
struct hlist_head *mcast_list,
struct batadv_mcast_mla_flags *flags)
{
static const u8 prefix[] = {0x33, 0x33};
struct batadv_hw_addr *new;
struct in_device *in_dev;
u8 mcast_addr[ETH_ALEN];
struct ip_mc_list *pmc;
int ret = 0;

if (flags->tvlv_flags & BATADV_MCAST_WANT_ALL_IPV4)
return 0;

rcu_read_lock();

return memcmp(prefix, addr, sizeof(prefix)) == 0;
in_dev = __in_dev_get_rcu(dev);
if (!in_dev) {
rcu_read_unlock();
return 0;
}

for (pmc = rcu_dereference(in_dev->mc_list); pmc;
pmc = rcu_dereference(pmc->next_rcu)) {
ip_eth_mc_map(pmc->multiaddr, mcast_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);
ret++;
}
rcu_read_unlock();

return ret;
}

/**
* batadv_mcast_mla_softif_get() - get softif multicast listeners
* batadv_mcast_mla_softif_get_ipv6() - get softif IPv6 multicast listeners
* @dev: the device to collect multicast addresses from
* @mcast_list: a list to put found addresses into
* @flags: flags indicating the new multicast state
*
* Collects multicast addresses of multicast listeners residing
* Collects multicast addresses of IPv6 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.
*/
#if IS_ENABLED(CONFIG_IPV6)
static int
batadv_mcast_mla_softif_get(struct net_device *dev,
struct hlist_head *mcast_list,
struct batadv_mcast_mla_flags *flags)
batadv_mcast_mla_softif_get_ipv6(struct net_device *dev,
struct hlist_head *mcast_list,
struct batadv_mcast_mla_flags *flags)
{
bool all_ipv4 = flags->tvlv_flags & BATADV_MCAST_WANT_ALL_IPV4;
bool all_ipv6 = flags->tvlv_flags & BATADV_MCAST_WANT_ALL_IPV6;
struct net_device *bridge = batadv_mcast_get_bridge(dev);
struct netdev_hw_addr *mc_list_entry;
struct batadv_hw_addr *new;
struct inet6_dev *in6_dev;
u8 mcast_addr[ETH_ALEN];
struct ifmcaddr6 *pmc6;
int ret = 0;

netif_addr_lock_bh(bridge ? bridge : dev);
netdev_for_each_mc_addr(mc_list_entry, bridge ? bridge : dev) {
if (all_ipv4 && batadv_mcast_addr_is_ipv4(mc_list_entry->addr))
if (flags->tvlv_flags & BATADV_MCAST_WANT_ALL_IPV6)
return 0;

rcu_read_lock();

in6_dev = __in6_dev_get(dev);
if (!in6_dev) {
rcu_read_unlock();
return 0;
}

read_lock_bh(&in6_dev->lock);
for (pmc6 = in6_dev->mc_list; pmc6; pmc6 = pmc6->next) {
if (IPV6_ADDR_MC_SCOPE(&pmc6->mca_addr) <
IPV6_ADDR_SCOPE_LINKLOCAL)
continue;

if (all_ipv6 && batadv_mcast_addr_is_ipv6(mc_list_entry->addr))
ipv6_eth_mc_map(&pmc6->mca_addr, mcast_addr);

if (batadv_mcast_mla_is_duplicate(mcast_addr, mcast_list))
continue;

new = kmalloc(sizeof(*new), GFP_ATOMIC);
Expand All @@ -244,36 +304,70 @@ batadv_mcast_mla_softif_get(struct net_device *dev,
break;
}

ether_addr_copy(new->addr, mc_list_entry->addr);
ether_addr_copy(new->addr, mcast_addr);
hlist_add_head(&new->list, mcast_list);
ret++;
}
netif_addr_unlock_bh(bridge ? bridge : dev);

if (bridge)
dev_put(bridge);
read_unlock_bh(&in6_dev->lock);
rcu_read_unlock();

return ret;
}
#else
static inline int
batadv_mcast_mla_softif_get_ipv6(struct net_device *dev,
struct hlist_head *mcast_list,
struct batadv_mcast_mla_flags *flags)
{
return 0;
}
#endif

/**
* 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
* 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
* @flags: flags indicating the new multicast state
*
* Return: true if the given address is already in the given list.
* Otherwise returns false.
* 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 bool batadv_mcast_mla_is_duplicate(u8 *mcast_addr,
struct hlist_head *mcast_list)
static int
batadv_mcast_mla_softif_get(struct net_device *dev,
struct hlist_head *mcast_list,
struct batadv_mcast_mla_flags *flags)
{
struct batadv_hw_addr *mcast_entry;
struct net_device *bridge = batadv_mcast_get_bridge(dev);
int ret4, ret6 = 0;

hlist_for_each_entry(mcast_entry, mcast_list, list)
if (batadv_compare_eth(mcast_entry->addr, mcast_addr))
return true;
if (bridge)
dev = bridge;

return false;
ret4 = batadv_mcast_mla_softif_get_ipv4(dev, mcast_list, flags);
if (ret4 < 0)
goto out;

ret6 = batadv_mcast_mla_softif_get_ipv6(dev, mcast_list, flags);
if (ret6 < 0) {
ret4 = 0;
goto out;
}

out:
if (bridge)
dev_put(bridge);

return ret4 + ret6;
}

/**
Expand Down

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