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 <[email protected]> --- main.c | 6 +++ main.h | 1 + multicast.c | 135 ++++++++++++++++++++++++++++++++++++++++++++++++++---- packet.h | 9 ++++ soft-interface.c | 1 + types.h | 12 +++++ 6 files changed, 156 insertions(+), 8 deletions(-) diff --git a/main.c b/main.c index 8f11b67..57b09fa 100644 --- a/main.c +++ b/main.c @@ -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); diff --git a/main.h b/main.h index dc6b4a2..a31da5a 100644 --- a/main.h +++ b/main.h @@ -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> diff --git a/multicast.c b/multicast.c index 127ba50..ebfbf6e 100644 --- a/multicast.c +++ b/multicast.c @@ -272,9 +272,48 @@ out: } /** + * 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 + * + * Check whether the given IPv4 packet has the potential to + * be forwarded with a mode more optimal than classic flooding. + * + * If so then return 0. Otherwise -EINVAL is returned or -ENOMEM if we are + * out of memory. + */ +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 * * Check whether the given IPv6 packet has the potential to * be forwarded with a mode more optimal than classic flooding. @@ -283,7 +322,8 @@ out: * 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; @@ -304,7 +344,7 @@ 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; } @@ -313,6 +353,7 @@ 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 * * Check whether the given multicast ethernet frame has the potential to * be forwarded with a mode more optimal than classic flooding. @@ -321,7 +362,8 @@ static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv, * out 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); @@ -332,8 +374,12 @@ 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; } @@ -356,6 +402,33 @@ batadv_mcast_forw_tt_node_get(struct batadv_priv *bat_priv, } /** + * 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 + * + * Return an orig_node which has the BATADV_MCAST_WANT_ALL_UNSNOOPABLES flag set + * and increase its refcount. + */ +static struct batadv_orig_node * +batadv_mcast_forw_unsnoop_node_get(struct batadv_priv *bat_priv) +{ + struct batadv_orig_node *orig_node; + + rcu_read_lock(); + hlist_for_each_entry_rcu(orig_node, + &bat_priv->mcast.want_all_unsnoopables_list, + mcast_want_all_unsnoopables_node) { + if (atomic_inc_not_zero(&orig_node->refcount)) + goto unlock; + } + + orig_node = NULL; + +unlock: + 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 @@ -370,9 +443,10 @@ batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb, struct batadv_orig_node **orig) { struct ethhdr *ethhdr; - int ret, tt_count; + bool is_unsnoopable = false; + int ret, tt_count, unsnoop_count, total_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) @@ -382,10 +456,18 @@ 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; @@ -398,6 +480,39 @@ 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 * @orig: the orig_node of the ogm @@ -441,6 +556,8 @@ 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; } @@ -477,4 +594,6 @@ 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); } diff --git a/packet.h b/packet.h index e8c483d..0aada24 100644 --- a/packet.h +++ b/packet.h @@ -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 diff --git a/soft-interface.c b/soft-interface.c index 1a643fe..db6feca 100644 --- a/soft-interface.c +++ b/soft-interface.c @@ -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); diff --git a/types.h b/types.h index c28fc4a..1a674cb 100644 --- a/types.h +++ b/types.h @@ -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 -- 1.7.10.4
