With this patch IGMP or MLD reports are only forwarded to the selected
IGMP/MLD querier as RFC4541 suggests. This is necessary to avoid
multicast packet loss in bridged scenarios later:
An IGMPv2/MLDv1 querier does not actively join the multicast group the
reports are sent to. Because of this, this leads to snooping
bridges/switches not being able to learn of multicast listeners in the
mesh and wrongly shutting down ports for multicast traffic to the mesh.
---
net/batman-adv/Kconfig | 1 +
net/batman-adv/main.h | 6 +-
net/batman-adv/multicast.c | 256 ++++++++++++++++++++++++++++++++++++++-
net/batman-adv/multicast.h | 8 ++
net/batman-adv/soft-interface.c | 11 ++
net/batman-adv/types.h | 14 +++
6 files changed, 289 insertions(+), 7 deletions(-)
diff --git a/net/batman-adv/Kconfig b/net/batman-adv/Kconfig
index c6fc8f7..36153da 100644
--- a/net/batman-adv/Kconfig
+++ b/net/batman-adv/Kconfig
@@ -5,6 +5,7 @@
config BATMAN_ADV
tristate "B.A.T.M.A.N. Advanced Meshing Protocol"
depends on NET
+ depends on !BATMAN_ADV_MCAST || IPV6 || IPV6=n
select CRC16
select LIBCRC32C
default n
diff --git a/net/batman-adv/main.h b/net/batman-adv/main.h
index 4d23188..b6d3a73 100644
--- a/net/batman-adv/main.h
+++ b/net/batman-adv/main.h
@@ -178,9 +178,11 @@ enum batadv_uev_type {
#include <net/addrconf.h> /* ipv6 address stuff */
#include <linux/ip.h>
#include <net/rtnetlink.h>
+#include <net/mld.h>
#include <linux/jiffies.h>
#include <linux/seq_file.h>
#include <linux/if_vlan.h>
+#include <linux/igmp.h>
#include "types.h"
@@ -221,6 +223,7 @@ __be32 batadv_skb_crc32(struct sk_buff *skb, u8
*payload_ptr);
* @BATADV_DBG_BLA: bridge loop avoidance messages
* @BATADV_DBG_DAT: ARP snooping and DAT related messages
* @BATADV_DBG_NC: network coding related messages
+ * @BATADV_DBG_MCAST: multicast related messages
* @BATADV_DBG_ALL: the union of all the above log levels
*/
enum batadv_dbg_level {
@@ -230,7 +233,8 @@ enum batadv_dbg_level {
BATADV_DBG_BLA = BIT(3),
BATADV_DBG_DAT = BIT(4),
BATADV_DBG_NC = BIT(5),
- BATADV_DBG_ALL = 63,
+ BATADV_DBG_MCAST = BIT(6),
+ BATADV_DBG_ALL = 127,
};
#ifdef CONFIG_BATMAN_ADV_DEBUG
diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c
index b24e4bb..a6eff07 100644
--- a/net/batman-adv/multicast.c
+++ b/net/batman-adv/multicast.c
@@ -247,10 +247,76 @@ out:
}
/**
+ * batadv_mcast_is_report_ipv4 - check for IGMP reports (and queries)
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: the ethernet frame destined for the mesh
+ * @orig: if IGMP report: to be set to the querier to forward the skb to
+ *
+ * Checks whether the given frame is an IGMP report and if so sets the
+ * orig pointer to the originator of the selected IGMP querier if one exists
+ * and returns true. Otherwise returns false.
+ *
+ * If the packet is a general IGMP query instead then we delete the memorized,
+ * foreign IGMP querier (if one exists): We became the selected querier and
+ * therefore do not need to forward reports into the mesh.
+ *
+ * This call might reallocate skb data.
+ */
+static bool batadv_mcast_is_report_ipv4(struct batadv_priv *bat_priv,
+ struct sk_buff *skb,
+ struct batadv_orig_node **orig)
+{
+ struct batadv_mcast_querier_state *querier;
+ struct batadv_orig_node *orig_node;
+
+ if (ip_mc_check_igmp(skb, NULL) < 0)
+ return false;
+
+ querier = &bat_priv->mcast.querier_ipv4;
+
+ switch (igmp_hdr(skb)->type) {
+ case IGMP_HOST_MEMBERSHIP_REPORT:
+ case IGMPV2_HOST_MEMBERSHIP_REPORT:
+ case IGMPV3_HOST_MEMBERSHIP_REPORT:
+ rcu_read_lock();
+ orig_node = rcu_dereference(querier->orig);
+ if (orig_node && atomic_inc_not_zero(&orig_node->refcount)) {
+ /* TODO: include multicast routers via MRD (RFC4286) */
+ batadv_dbg(BATADV_DBG_MCAST, bat_priv,
+ "Redirecting IGMP Report to %pM\n",
+ orig_node->orig);
+ *orig = orig_node;
+ }
+ rcu_read_unlock();
+
+ return true;
+ case IGMP_HOST_MEMBERSHIP_QUERY:
+ /* RFC4541, section 2.1.1.1.b) says:
+ * ignore general queries from 0.0.0.0
+ */
+ if (!ip_hdr(skb)->saddr || igmp_hdr(skb)->group)
+ break;
+
+ spin_lock_bh(&querier->orig_lock);
+ orig_node = rcu_dereference(querier->orig);
+ if (orig_node)
+ rcu_assign_pointer(querier->orig, NULL);
+ spin_unlock_bh(&querier->orig_lock);
+
+ batadv_dbg(BATADV_DBG_MCAST, bat_priv,
+ "Snooped own IGMP Query\n");
+ break;
+ }
+
+ 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
+ * @orig: for IGMP reports: to be set to the querier to forward the skb to
*
* Checks whether the given IPv4 packet has the potential to be forwarded with
a
* mode more optimal than classic flooding.
@@ -260,7 +326,8 @@ out:
*/
static int batadv_mcast_forw_mode_check_ipv4(struct batadv_priv *bat_priv,
struct sk_buff *skb,
- bool *is_unsnoopable)
+ bool *is_unsnoopable,
+ struct batadv_orig_node **orig)
{
struct iphdr *iphdr;
@@ -268,6 +335,9 @@ static int batadv_mcast_forw_mode_check_ipv4(struct
batadv_priv *bat_priv,
if (!pskb_may_pull(skb, sizeof(struct ethhdr) + sizeof(*iphdr)))
return -ENOMEM;
+ if (batadv_mcast_is_report_ipv4(bat_priv, skb, orig))
+ return 0;
+
iphdr = ip_hdr(skb);
/* TODO: Implement Multicast Router Discovery (RFC4286),
@@ -284,11 +354,74 @@ static int batadv_mcast_forw_mode_check_ipv4(struct
batadv_priv *bat_priv,
return 0;
}
+#if IS_ENABLED(CONFIG_IPV6)
+/**
+ * batadv_mcast_is_report_ipv6 - check for MLD reports (and queries)
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: the ethernet frame destined for the mesh
+ * @orig: if MLD report: to be set to the querier to forward the skb to
+ *
+ * Checks whether the given frame is an MLD report and if so sets the
+ * orig pointer to the originator of the selected MLD querier if one exists
+ * and returns true. Otherwise returns false.
+ *
+ * If the packet is a general MLD query instead then we delete the memorized,
+ * foreign MLD querier (if one exists): We became the selected querier and
+ * therefore do not need to forward reports into the mesh.
+ *
+ * This call might reallocate skb data.
+ */
+static bool batadv_mcast_is_report_ipv6(struct batadv_priv *bat_priv,
+ struct sk_buff *skb,
+ struct batadv_orig_node **orig)
+{
+ struct mld_msg *mld;
+ struct batadv_mcast_querier_state *querier;
+ struct batadv_orig_node *orig_node;
+ int ret;
+
+ if (ipv6_mc_check_mld(skb, NULL) < 0)
+ return false;
+
+ querier = &bat_priv->mcast.querier_ipv6;
+ mld = (struct mld_msg *)icmp6_hdr(skb);
+
+ switch (mld->mld_type) {
+ case ICMPV6_MGM_REPORT:
+ case ICMPV6_MLD2_REPORT:
+ rcu_read_lock();
+ orig_node = rcu_dereference(querier->orig);
+ if (orig_node && atomic_inc_not_zero(&orig_node->refcount)) {
+ /* TODO: include multicast routers via MRD (RFC4286) */
+ batadv_dbg(BATADV_DBG_MCAST, bat_priv,
+ "Redirecting MLD Report to %pM\n",
+ orig_node->orig);
+ *orig = orig_node;
+ }
+ rcu_read_unlock();
+
+ return true;
+ case ICMPV6_MGM_QUERY:
+ spin_lock_bh(&querier->orig_lock);
+ orig_node = rcu_dereference(querier->orig);
+ if (orig_node)
+ rcu_assign_pointer(querier->orig, NULL);
+ spin_unlock_bh(&querier->orig_lock);
+
+ batadv_dbg(BATADV_DBG_MCAST, bat_priv,
+ "Snooped own MLD Query\n");
+ break;
+ }
+
+ 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
+ * @orig: for MLD reports: to be set to the querier to forward the skb to
*
* Checks whether the given IPv6 packet has the potential to be forwarded with
a
* mode more optimal than classic flooding.
@@ -298,7 +431,8 @@ static int batadv_mcast_forw_mode_check_ipv4(struct
batadv_priv *bat_priv,
*/
static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv,
struct sk_buff *skb,
- bool *is_unsnoopable)
+ bool *is_unsnoopable,
+ struct batadv_orig_node **orig)
{
struct ipv6hdr *ip6hdr;
@@ -306,6 +440,9 @@ static int batadv_mcast_forw_mode_check_ipv6(struct
batadv_priv *bat_priv,
if (!pskb_may_pull(skb, sizeof(struct ethhdr) + sizeof(*ip6hdr)))
return -ENOMEM;
+ if (batadv_mcast_is_report_ipv6(bat_priv, skb, orig))
+ return 0;
+
ip6hdr = ipv6_hdr(skb);
/* TODO: Implement Multicast Router Discovery (RFC4286),
@@ -322,6 +459,7 @@ static int batadv_mcast_forw_mode_check_ipv6(struct
batadv_priv *bat_priv,
return 0;
}
+#endif
/**
* batadv_mcast_forw_mode_check - check for optimized forwarding potential
@@ -337,7 +475,8 @@ static int batadv_mcast_forw_mode_check_ipv6(struct
batadv_priv *bat_priv,
*/
static int batadv_mcast_forw_mode_check(struct batadv_priv *bat_priv,
struct sk_buff *skb,
- bool *is_unsnoopable)
+ bool *is_unsnoopable,
+ struct batadv_orig_node **orig)
{
struct ethhdr *ethhdr = eth_hdr(skb);
@@ -350,10 +489,12 @@ static int batadv_mcast_forw_mode_check(struct
batadv_priv *bat_priv,
switch (ntohs(ethhdr->h_proto)) {
case ETH_P_IP:
return batadv_mcast_forw_mode_check_ipv4(bat_priv, skb,
- is_unsnoopable);
+ is_unsnoopable, orig);
+#if IS_ENABLED(CONFIG_IPV6)
case ETH_P_IPV6:
return batadv_mcast_forw_mode_check_ipv6(bat_priv, skb,
- is_unsnoopable);
+ is_unsnoopable, orig);
+#endif
default:
return -EINVAL;
}
@@ -521,12 +662,16 @@ batadv_mcast_forw_mode(struct batadv_priv *bat_priv,
struct sk_buff *skb,
bool is_unsnoopable = false;
struct ethhdr *ethhdr;
- ret = batadv_mcast_forw_mode_check(bat_priv, skb, &is_unsnoopable);
+ ret = batadv_mcast_forw_mode_check(bat_priv, skb, &is_unsnoopable,
+ orig);
if (ret == -ENOMEM)
return BATADV_FORW_NONE;
else if (ret < 0)
return BATADV_FORW_ALL;
+ if (*orig)
+ return BATADV_FORW_SINGLE;
+
ethhdr = eth_hdr(skb);
tt_count = batadv_tt_global_hash_count(bat_priv, ethhdr->h_dest,
@@ -558,6 +703,105 @@ batadv_mcast_forw_mode(struct batadv_priv *bat_priv,
struct sk_buff *skb,
}
/**
+ * batadv_mcast_snoop_query_ipv4 - snoop for the selected MLD querier
+ * @skb: the unencapsulated ethernet frame coming from the mesh
+ * @orig_node: the originator this frame came from
+ *
+ * Checks whether the given frame is a general IGMP query from the selected
+ * querier and if so memorizes the originator this frame came from.
+ */
+static void batadv_mcast_snoop_query_ipv4(struct sk_buff *skb,
+ struct batadv_orig_node *orig_node)
+{
+ struct batadv_mcast_querier_state *querier;
+
+ if (ip_mc_check_igmp(skb, NULL) < 0)
+ return;
+
+ /* we are only interested in general queries (group == 0.0.0.0) */
+ if (igmp_hdr(skb)->type != IGMP_HOST_MEMBERSHIP_QUERY ||
+ igmp_hdr(skb)->group)
+ return;
+
+ /* RFC4541, section 2.1.1.1.b) says: ignore queries from 0.0.0.0 */
+ if (!ip_hdr(skb)->saddr)
+ return;
+
+ querier = &orig_node->bat_priv->mcast.querier_ipv4;
+
+ spin_lock_bh(&querier->orig_lock);
+ rcu_assign_pointer(querier->orig, orig_node);
+ spin_unlock_bh(&querier->orig_lock);
+
+ batadv_dbg(BATADV_DBG_MCAST, orig_node->bat_priv,
+ "Snooped IGMP Query from originator %pM\n", orig_node->orig);
+}
+
+#if IS_ENABLED(CONFIG_IPV6)
+/**
+ * batadv_mcast_snoop_query_ipv6 - snoop for the selected MLD querier
+ * @skb: the unencapsulated ethernet frame coming from the mesh
+ * @orig_node: the originator this frame came from
+ *
+ * Checks whether the given frame is a general MLD query from the selected
+ * querier and if so memorizes the originator this frame came from.
+ */
+static void batadv_mcast_snoop_query_ipv6(struct sk_buff *skb,
+ struct batadv_orig_node *orig_node)
+{
+ struct mld_msg *mld;
+ struct batadv_mcast_querier_state *querier;
+
+ if (ipv6_mc_check_mld(skb, NULL) < 0)
+ return;
+
+ mld = (struct mld_msg *)icmp6_hdr(skb);
+
+ /* we are only interested in general queries (mca == ::) */
+ if (mld->mld_type != ICMPV6_MGM_QUERY ||
+ !ipv6_addr_any(&mld->mld_mca))
+ return;
+
+ querier = &orig_node->bat_priv->mcast.querier_ipv6;
+
+ spin_lock_bh(&querier->orig_lock);
+ rcu_assign_pointer(querier->orig, orig_node);
+ spin_unlock_bh(&querier->orig_lock);
+
+ batadv_dbg(BATADV_DBG_MCAST, orig_node->bat_priv,
+ "Snooped MLD Query from originator %pM\n", orig_node->orig);
+}
+#endif
+
+/**
+ * batadv_mcast_snoop_query - snoop the selected IGMP/MLD querier
+ * @skb: the unencapsulated ethernet frame coming from the mesh
+ * @orig_node: the originator this frame came from
+ *
+ * Checks whether the given frame is a general IGMP or MLD query
+ * from the selected querier and if so memorizes the originator
+ * this frame came from.
+ *
+ * This call might reallocate skb data.
+ */
+void batadv_mcast_snoop_query(struct sk_buff *skb,
+ struct batadv_orig_node *orig_node)
+{
+ struct ethhdr *ethhdr = eth_hdr(skb);
+
+ switch (ntohs(ethhdr->h_proto)) {
+ case ETH_P_IP:
+ batadv_mcast_snoop_query_ipv4(skb, orig_node);
+ break;
+#if IS_ENABLED(CONFIG_IPV6)
+ case ETH_P_IPV6:
+ batadv_mcast_snoop_query_ipv6(skb, orig_node);
+ break;
+#endif
+ }
+}
+
+/**
* 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
diff --git a/net/batman-adv/multicast.h b/net/batman-adv/multicast.h
index 3a44ebd..3727beb 100644
--- a/net/batman-adv/multicast.h
+++ b/net/batman-adv/multicast.h
@@ -40,6 +40,9 @@ enum batadv_forw_mode
batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb,
struct batadv_orig_node **mcast_single_orig);
+void batadv_mcast_snoop_query(struct sk_buff *skb,
+ struct batadv_orig_node *orig_node);
+
void batadv_mcast_init(struct batadv_priv *bat_priv);
void batadv_mcast_free(struct batadv_priv *bat_priv);
@@ -59,6 +62,11 @@ batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct
sk_buff *skb,
return BATADV_FORW_ALL;
}
+static inline void batadv_mcast_snoop_query(struct sk_buff *skb,
+ struct batadv_orig_node *orig_node)
+{
+}
+
static inline int batadv_mcast_init(struct batadv_priv *bat_priv)
{
return 0;
diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index 5ec31d7..445d80e 100644
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -176,6 +176,8 @@ static int batadv_interface_tx(struct sk_buff *skb,
if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
goto dropped;
+ skb_set_network_header(skb, ETH_HLEN);
+
soft_iface->trans_start = jiffies;
vid = batadv_get_vid(skb, 0);
ethhdr = eth_hdr(skb);
@@ -366,6 +368,7 @@ void batadv_interface_rx(struct net_device *soft_iface,
skb_pull_rcsum(skb, hdr_size);
skb_reset_mac_header(skb);
+ skb_set_network_header(skb, ETH_HLEN);
/* clean the netfilter state now that the batman-adv header has been
* removed
@@ -428,6 +431,9 @@ void batadv_interface_rx(struct net_device *soft_iface,
skb->mark &= ~bat_priv->isolation_mark_mask;
skb->mark |= bat_priv->isolation_mark;
}
+
+ if (orig_node)
+ batadv_mcast_snoop_query(skb, orig_node);
} else if (batadv_is_ap_isolated(bat_priv, ethhdr->h_source,
ethhdr->h_dest, vid)) {
goto dropped;
@@ -738,6 +744,11 @@ static int batadv_softif_init_late(struct net_device *dev)
atomic_set(&bat_priv->distributed_arp_table, 1);
#endif
#ifdef CONFIG_BATMAN_ADV_MCAST
+ rcu_assign_pointer(bat_priv->mcast.querier_ipv4.orig, NULL);
+ spin_lock_init(&bat_priv->mcast.querier_ipv4.orig_lock);
+ rcu_assign_pointer(bat_priv->mcast.querier_ipv6.orig, NULL);
+ spin_lock_init(&bat_priv->mcast.querier_ipv6.orig_lock);
+
bat_priv->mcast.flags = BATADV_NO_FLAGS;
atomic_set(&bat_priv->multicast_mode, 1);
atomic_set(&bat_priv->mcast.num_disabled, 0);
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index 9398c3f..a0f5bf8 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -623,12 +623,24 @@ struct batadv_priv_dat {
#ifdef CONFIG_BATMAN_ADV_MCAST
/**
+ * struct batadv_mcast_querier_state - IGMP/MLD querier state when bridged
+ * @orig: node on which the selected querier resides
+ * @orig_lock: protects updates of the selected querier in 'orig'
+ */
+struct batadv_mcast_querier_state {
+ struct batadv_orig_node __rcu *orig; /* rcu protected pointer */
+ spinlock_t orig_lock; /* protects updates of orig */
+};
+
+/**
* 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
* @want_all_ipv4_list: a list of orig_nodes wanting all IPv4 multicast traffic
* @want_all_ipv6_list: a list of orig_nodes wanting all IPv6 multicast traffic
+ * @querier_ipv4: the current state of an IGMP querier in the mesh
+ * @querier_ipv6: the current state of an MLD querier in the mesh
* @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
@@ -643,6 +655,8 @@ struct batadv_priv_mcast {
struct hlist_head want_all_unsnoopables_list;
struct hlist_head want_all_ipv4_list;
struct hlist_head want_all_ipv6_list;
+ struct batadv_mcast_querier_state querier_ipv4;
+ struct batadv_mcast_querier_state querier_ipv6;
uint8_t flags;
bool enabled;
atomic_t num_disabled;
--
1.7.10.4
