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batman-adv: Add IPv4 link-local/IPv6-ll-all-nodes multicast support 

With this patch a node may additionally perform the dropping or
unicasting behaviour for a link-local IPv4 and link-local-all-nodes
IPv6 multicast packet, too.

The extra counter and BATADV_MCAST_WANT_ALL_UNSNOOPABLES flag is needed
because with a future bridge snooping support integration a node with a
bridge on top of its soft interface is not able to reliably detect its
multicast listeners for IPv4 link-local and the IPv6
link-local-all-nodes addresses anymore (see RFC4541, section 2.1.2.2
and section 3).

Even though this new flag does make "no difference" now, it'll ensure
a seamless integration of multicast bridge support without needing to
break compatibility later.

Also note, that even with multicast bridge support it won't be possible
to optimize 224.0.0.x and ff02::1 towards nodes with bridges, they will
always receive these ranges.

Signed-off-by: Linus Lüssing <linus.luessing@web.de>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
This commit is contained in:
Linus Lüssing 2014-02-15 17:47:53 +01:00 committed by Antonio Quartulli
parent 1d8ab8d3c1
commit ab49886e3d
6 changed files with 156 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
net/batman-adv/main.c
View File

@ -111,6 +111,9 @@ int batadv_mesh_init(struct net_device *soft_iface)
spin_lock_init(&bat_priv->tt.last_changeset_lock);
spin_lock_init(&bat_priv->tt.commit_lock);
spin_lock_init(&bat_priv->gw.list_lock);
#ifdef CONFIG_BATMAN_ADV_MCAST
spin_lock_init(&bat_priv->mcast.want_lists_lock);
#endif
spin_lock_init(&bat_priv->tvlv.container_list_lock);
spin_lock_init(&bat_priv->tvlv.handler_list_lock);
spin_lock_init(&bat_priv->softif_vlan_list_lock);
@ -118,6 +121,9 @@ int batadv_mesh_init(struct net_device *soft_iface)
INIT_HLIST_HEAD(&bat_priv->forw_bat_list);
INIT_HLIST_HEAD(&bat_priv->forw_bcast_list);
INIT_HLIST_HEAD(&bat_priv->gw.list);
#ifdef CONFIG_BATMAN_ADV_MCAST
INIT_HLIST_HEAD(&bat_priv->mcast.want_all_unsnoopables_list);
#endif
INIT_LIST_HEAD(&bat_priv->tt.changes_list);
INIT_LIST_HEAD(&bat_priv->tt.req_list);
INIT_LIST_HEAD(&bat_priv->tt.roam_list);

1
net/batman-adv/main.h
View File

@ -177,6 +177,7 @@ enum batadv_uev_type {
#include <linux/slab.h>
#include <net/sock.h> /* struct sock */
#include <net/addrconf.h> /* ipv6 address stuff */
#include <linux/ip.h>
#include <net/rtnetlink.h>
#include <linux/jiffies.h>
#include <linux/seq_file.h>

135
net/batman-adv/multicast.c
View File

@ -247,10 +247,49 @@ out:
batadv_mcast_mla_list_free(&mcast_list);
}
/**
* 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.
*
* If so then returns 0. Otherwise -EINVAL is returned 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;
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_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.
@ -259,7 +298,8 @@ out:
* of memory.
*/
static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv,
struct sk_buff *skb)
struct sk_buff *skb,
bool *is_unsnoopable)
{
struct ipv6hdr *ip6hdr;
@ -279,7 +319,7 @@ static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv,
* not snoopable (see RFC4541, section 3, paragraph 3)
*/
if (ipv6_addr_is_ll_all_nodes(&ip6hdr->daddr))
return -EINVAL;
*is_unsnoopable = true;
return 0;
}
@ -288,6 +328,7 @@ static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv,
* 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.
@ -296,7 +337,8 @@ static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv,
* of memory.
*/
static int batadv_mcast_forw_mode_check(struct batadv_priv *bat_priv,
struct sk_buff *skb)
struct sk_buff *skb,
bool *is_unsnoopable)
{
struct ethhdr *ethhdr = eth_hdr(skb);
@ -307,8 +349,12 @@ static int batadv_mcast_forw_mode_check(struct batadv_priv *bat_priv,
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:
return batadv_mcast_forw_mode_check_ipv6(bat_priv, skb);
return batadv_mcast_forw_mode_check_ipv6(bat_priv, skb,
is_unsnoopable);
default:
return -EINVAL;
}
@ -330,6 +376,33 @@ batadv_mcast_forw_tt_node_get(struct batadv_priv *bat_priv,
ethhdr->h_dest, BATADV_NO_FLAGS);
}
/**
* batadv_mcast_want_forw_unsnoop_node_get - get a node with an unsnoopable flag
* @bat_priv: the bat priv with all the soft interface information
*
* Returns 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 (!atomic_inc_not_zero(&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
@ -344,10 +417,11 @@ 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, unsnoop_count, total_count;
bool is_unsnoopable = false;
struct ethhdr *ethhdr;
int ret, tt_count;
ret = batadv_mcast_forw_mode_check(bat_priv, skb);
ret = batadv_mcast_forw_mode_check(bat_priv, skb, &is_unsnoopable);
if (ret == -ENOMEM)
return BATADV_FORW_NONE;
else if (ret < 0)
@ -357,10 +431,18 @@ batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb,
tt_count = batadv_tt_global_hash_count(bat_priv, ethhdr->h_dest,
BATADV_NO_FLAGS);
unsnoop_count = !is_unsnoopable ? 0 :
atomic_read(&bat_priv->mcast.num_want_all_unsnoopables);
switch (tt_count) {
total_count = tt_count + unsnoop_count;
switch (total_count) {
case 1:
*orig = batadv_mcast_forw_tt_node_get(bat_priv, ethhdr);
if (tt_count)
*orig = batadv_mcast_forw_tt_node_get(bat_priv, ethhdr);
else if (unsnoop_count)
*orig = batadv_mcast_forw_unsnoop_node_get(bat_priv);
if (*orig)
return BATADV_FORW_SINGLE;
@ -372,6 +454,39 @@ batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb,
}
}
/**
* 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.
*/
static void batadv_mcast_want_unsnoop_update(struct batadv_priv *bat_priv,
struct batadv_orig_node *orig,
uint8_t mcast_flags)
{
/* 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);
hlist_add_head_rcu(&orig->mcast_want_all_unsnoopables_node,
&bat_priv->mcast.want_all_unsnoopables_list);
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);
hlist_del_rcu(&orig->mcast_want_all_unsnoopables_node);
spin_unlock_bh(&bat_priv->mcast.want_lists_lock);
}
}
/**
* batadv_mcast_tvlv_ogm_handler_v1 - process incoming multicast tvlv container
* @bat_priv: the bat priv with all the soft interface information
@ -416,6 +531,8 @@ static void batadv_mcast_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
(tvlv_value_len >= sizeof(mcast_flags)))
mcast_flags = *(uint8_t *)tvlv_value;
batadv_mcast_want_unsnoop_update(bat_priv, orig, mcast_flags);
orig->mcast_flags = mcast_flags;
}
@ -452,4 +569,6 @@ void batadv_mcast_purge_orig(struct batadv_orig_node *orig)
if (!(orig->capabilities & BATADV_ORIG_CAPA_HAS_MCAST))
atomic_dec(&bat_priv->mcast.num_disabled);
batadv_mcast_want_unsnoop_update(bat_priv, orig, BATADV_NO_FLAGS);
}

9
net/batman-adv/packet.h
View File

@ -89,6 +89,15 @@ enum batadv_icmp_packettype {
BATADV_PARAMETER_PROBLEM = 12,
};
/**
* enum batadv_mcast_flags - flags for multicast capabilities and settings
* @BATADV_MCAST_WANT_ALL_UNSNOOPABLES: we want all packets destined for
* 224.0.0.0/24 or ff02::1
*/
enum batadv_mcast_flags {
BATADV_MCAST_WANT_ALL_UNSNOOPABLES = BIT(0),
};
/* tt data subtypes */
#define BATADV_TT_DATA_TYPE_MASK 0x0F

1
net/batman-adv/soft-interface.c
View File

@ -710,6 +710,7 @@ static int batadv_softif_init_late(struct net_device *dev)
bat_priv->mcast.flags = BATADV_NO_FLAGS;
atomic_set(&bat_priv->multicast_mode, 1);
atomic_set(&bat_priv->mcast.num_disabled, 0);
atomic_set(&bat_priv->mcast.num_want_all_unsnoopables, 0);
#endif
atomic_set(&bat_priv->gw_mode, BATADV_GW_MODE_OFF);
atomic_set(&bat_priv->gw_sel_class, 20);

12
net/batman-adv/types.h
View File

@ -205,6 +205,8 @@ struct batadv_orig_bat_iv {
* @last_seen: time when last packet from this node was received
* @bcast_seqno_reset: time when the broadcast seqno window was reset
* @mcast_flags: multicast flags announced by the orig node
* @mcast_want_all_unsnoop_node: a list node for the
* mcast.want_all_unsnoopables list
* @capabilities: announced capabilities of this originator
* @capa_initialized: bitfield to remember whether a capability was initialized
* @last_ttvn: last seen translation table version number
@ -249,6 +251,7 @@ struct batadv_orig_node {
unsigned long bcast_seqno_reset;
#ifdef CONFIG_BATMAN_ADV_MCAST
uint8_t mcast_flags;
struct hlist_node mcast_want_all_unsnoopables_node;
#endif
uint8_t capabilities;
uint8_t capa_initialized;
@ -619,15 +622,24 @@ struct batadv_priv_dat {
/**
* struct batadv_priv_mcast - per mesh interface mcast data
* @mla_list: list of multicast addresses we are currently announcing via TT
* @want_all_unsnoopables_list: a list of orig_nodes wanting all unsnoopable
* multicast traffic
* @flags: the flags we have last sent in our mcast tvlv
* @enabled: whether the multicast tvlv is currently enabled
* @num_disabled: number of nodes that have no mcast tvlv
* @num_want_all_unsnoopables: number of nodes wanting unsnoopable IP traffic
* @want_lists_lock: lock for protecting modifications to mcast want lists
* (traversals are rcu-locked)
*/
struct batadv_priv_mcast {
struct hlist_head mla_list;
struct hlist_head want_all_unsnoopables_list;
uint8_t flags;
bool enabled;
atomic_t num_disabled;
atomic_t num_want_all_unsnoopables;
/* protects want_all_unsnoopables_list */
spinlock_t want_lists_lock;
};
#endif