Implement the preparation of a batman-adv multicast packet and use this under certain conditions.

For one thing this implements the capability to push a complete batman-adv multicast packet header, including a tracker TVLV with all originator destinations that have signaled interest in it, onto a given ethernet frame with an IP multicast packet inside.

For another checks are implemented to determine if encapsulating a multicast packet in this new batman-adv multicast packet type and using it is feasible. Those checks are:

1) Have all nodes signaled that they are capable of handling the new batman-adv multicast packet type? 2) Do all active hard interfaces of all nodes, including us, have an MTU of at least 1280 bytes? 3) Does a complete multicast packet header with all its destination addresses fit onto the given multicast packet / ethernet frame and does not exceed 1280 bytes?

If all checks passed then the new batman-adv multicast packet type will be used for transmission and distribution. Otherwise we fall back to one or more batman-adv unicast packet transmissions, if possible. Or if not possible we will fall back to classic flooding through a batman-adv broadcast packet.

Signed-off-by: Linus Lüssing linus.luessing@c0d3.blue --- net/batman-adv/multicast.c | 79 +++- net/batman-adv/multicast.h | 25 +- net/batman-adv/multicast_forw.c | 715 ++++++++++++++++++++++++++++++++ net/batman-adv/soft-interface.c | 6 +- net/batman-adv/types.h | 6 + 5 files changed, 823 insertions(+), 8 deletions(-)

diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c index f2b1e523fd85..d8ddb20fd732 100644 --- a/net/batman-adv/multicast.c +++ b/net/batman-adv/multicast.c @@ -1177,17 +1177,62 @@ static int batadv_mcast_forw_rtr_count(struct batadv_priv *bat_priv, } }

+/** + * batadv_mcast_forw_mode_by_count() - get forwarding mode by count + * @bat_priv: the bat priv with all the soft interface information + * @skb: the multicast packet to check + * @vid: the vlan identifier + * @is_routable: stores whether the destination is routable + * @count: the number of originators the multicast packet need to be sent to + * + * For a multicast packet with multiple destination originators, checks which + * mode to use. For BATADV_FORW_MCAST it also encapsulates the packet with a + * complete batman-adv multicast header. + * + * Return: + * BATADV_FORW_MCAST: If all nodes have multicast packet routing + * capabilities and an MTU >= 1280 on all hard interfaces (including us) + * and the encapsulated multicast packet with all destination addresses + * would still fit into an 1280 bytes batman-adv multicast packet + * (excluding the outer ethernet frame) and we could successfully push + * the full batman-adv multicast packet header. + * BATADV_FORW_UCASTS: If the packet cannot be sent in a batman-adv + * multicast packet and the amount of batman-adv unicast packets needed + * is smaller or equal to the configured multicast fanout. + * BATADV_FORW_BCAST: Otherwise. + */ +static enum batadv_forw_mode +batadv_mcast_forw_mode_by_count(struct batadv_priv *bat_priv, + struct sk_buff *skb, unsigned short vid, + int is_routable, int count) +{ + unsigned int mcast_hdrlen = batadv_mcast_forw_packet_hdrlen(count); + u8 own_tvlv_flags = bat_priv->mcast.mla_flags.tvlv_flags; + + if (!atomic_read(&bat_priv->mcast.num_no_mc_ptype_capa) && + own_tvlv_flags & BATADV_MCAST_HAVE_MC_PTYPE_CAPA && + skb->len + mcast_hdrlen <= IPV6_MIN_MTU && + batadv_mcast_forw_push(bat_priv, skb, vid, is_routable, count)) + return BATADV_FORW_MCAST; + + if (count <= atomic_read(&bat_priv->multicast_fanout)) + return BATADV_FORW_UCASTS; + + return BATADV_FORW_BCAST; +} + /** * 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 + * @vid: the vlan identifier * @is_routable: stores whether the destination is routable * * Return: The forwarding mode as enum batadv_forw_mode. */ enum batadv_forw_mode batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb, - int *is_routable) + unsigned short vid, int *is_routable) { int ret, tt_count, ip_count, unsnoop_count, total_count; bool is_unsnoopable = false; @@ -1217,10 +1262,8 @@ batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb, else if (unsnoop_count) return BATADV_FORW_BCAST;

- if (total_count <= atomic_read(&bat_priv->multicast_fanout)) - return BATADV_FORW_UCASTS; - - return BATADV_FORW_BCAST; + return batadv_mcast_forw_mode_by_count(bat_priv, skb, vid, *is_routable, + total_count); }

/** @@ -1780,6 +1823,31 @@ static void batadv_mcast_want_rtr6_update(struct batadv_priv *bat_priv, } }

+/** + * batadv_mcast_have_mc_ptype_update() - update multicast packet type counter + * @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_HAVE_MC_PTYPE_CAPA flag of this originator, orig, has + * toggled then this method updates the counter accordingly. + */ +static void batadv_mcast_have_mc_ptype_update(struct batadv_priv *bat_priv, + struct batadv_orig_node *orig, + u8 mcast_flags) +{ + lockdep_assert_held(&orig->mcast_handler_lock); + + /* switched from flag set to unset */ + if (!(mcast_flags & BATADV_MCAST_HAVE_MC_PTYPE_CAPA) && + orig->mcast_flags & BATADV_MCAST_HAVE_MC_PTYPE_CAPA) + atomic_inc(&bat_priv->mcast.num_no_mc_ptype_capa); + /* switched from flag unset to set */ + else if (mcast_flags & BATADV_MCAST_HAVE_MC_PTYPE_CAPA && + !(orig->mcast_flags & BATADV_MCAST_HAVE_MC_PTYPE_CAPA)) + atomic_dec(&bat_priv->mcast.num_no_mc_ptype_capa); +} + /** * batadv_mcast_tvlv_flags_get() - get multicast flags from an OGM TVLV * @enabled: whether the originator has multicast TVLV support enabled @@ -1848,6 +1916,7 @@ static void batadv_mcast_tvlv_ogm_handler(struct batadv_priv *bat_priv, batadv_mcast_want_ipv6_update(bat_priv, orig, mcast_flags); batadv_mcast_want_rtr4_update(bat_priv, orig, mcast_flags); batadv_mcast_want_rtr6_update(bat_priv, orig, mcast_flags); + batadv_mcast_have_mc_ptype_update(bat_priv, orig, mcast_flags);

orig->mcast_flags = mcast_flags; spin_unlock_bh(&orig->mcast_handler_lock); diff --git a/net/batman-adv/multicast.h b/net/batman-adv/multicast.h index a5c0f384bb9a..d97ee51d26f2 100644 --- a/net/batman-adv/multicast.h +++ b/net/batman-adv/multicast.h @@ -11,6 +11,7 @@

#include <linux/netlink.h> #include <linux/skbuff.h> +#include <linux/types.h>

/** * enum batadv_forw_mode - the way a packet should be forwarded as @@ -28,6 +29,12 @@ enum batadv_forw_mode { */ BATADV_FORW_UCASTS,

+ /** + * @BATADV_FORW_MCAST: forward the packet to some nodes via a + * batman-adv multicast packet + */ + BATADV_FORW_MCAST, + /** @BATADV_FORW_NONE: don't forward, drop it */ BATADV_FORW_NONE, }; @@ -36,7 +43,7 @@ enum batadv_forw_mode {

enum batadv_forw_mode batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb, - int *is_routable); + unsigned short vid, int *is_routable);

int batadv_mcast_forw_send(struct batadv_priv *bat_priv, struct sk_buff *skb, unsigned short vid, int is_routable); @@ -57,11 +64,18 @@ void batadv_mcast_purge_orig(struct batadv_orig_node *orig_node); int batadv_mcast_forw_tracker_tvlv_handler(struct batadv_priv *bat_priv, struct sk_buff *skb);

+unsigned int batadv_mcast_forw_packet_hdrlen(unsigned int num_dests); + +bool batadv_mcast_forw_push(struct batadv_priv *bat_priv, struct sk_buff *skb, + unsigned short vid, int is_routable, int count); + +int batadv_mcast_forw_mcsend(struct batadv_priv *bat_priv, struct sk_buff *skb); + #else

static inline enum batadv_forw_mode batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb, - int *is_routable) + unsigned short vid, int *is_routable) { return BATADV_FORW_BCAST; } @@ -99,6 +113,13 @@ static inline void batadv_mcast_purge_orig(struct batadv_orig_node *orig_node) { }

+static inline int batadv_mcast_forw_mcsend(struct batadv_priv *bat_priv, + struct sk_buff *skb) +{ + kfree_skb(skb); + return NET_XMIT_DROP; +} + #endif /* CONFIG_BATMAN_ADV_MCAST */

#endif /* _NET_BATMAN_ADV_MULTICAST_H_ */ diff --git a/net/batman-adv/multicast_forw.c b/net/batman-adv/multicast_forw.c index 08f31b977777..e3a603ec8f51 100644 --- a/net/batman-adv/multicast_forw.c +++ b/net/batman-adv/multicast_forw.c @@ -7,24 +7,612 @@ #include "multicast.h" #include "main.h"

+#include <linux/bug.h> +#include <linux/build_bug.h> #include <linux/byteorder/generic.h> #include <linux/errno.h> #include <linux/etherdevice.h> #include <linux/gfp.h> #include <linux/if_ether.h> +#include <linux/if_vlan.h> +#include <linux/ipv6.h> +#include <linux/limits.h> #include <linux/netdevice.h> +#include <linux/rculist.h> +#include <linux/rcupdate.h> #include <linux/skbuff.h> #include <linux/stddef.h> +#include <linux/string.h> #include <linux/types.h> #include <uapi/linux/batadv_packet.h>

+#include "bridge_loop_avoidance.h" #include "originator.h" #include "routing.h" #include "send.h" +#include "translation-table.h"

#define batadv_mcast_forw_tracker_for_each_dest(dest, num_dests) \ for (; num_dests; num_dests--, (dest) += ETH_ALEN)

+/** + * batadv_mcast_forw_skb_push() - skb_push and memorize amount of pushed bytes + * @skb: the skb to push onto + * @size: the amount of bytes to push + * @len: stores the total amount of bytes pushed + * + * Performs an skb_push() onto the given skb and adds the amount of pushed bytes + * to the given len pointer. + * + * Return: the return value of the skb_push() call. + */ +static void *batadv_mcast_forw_skb_push(struct sk_buff *skb, size_t size, + unsigned short *len) +{ + *len += size; + return skb_push(skb, size); +} + +/** + * batadv_mcast_forw_push_padding() - push 2 padding bytes to skb's front + * @skb: the skb to push onto + * @tvlv_len: stores the amount of currently pushed TVLV bytes + * + * Pushes two padding bytes to the front of the given skb. + * + * Return: On success a pointer to the first byte of the two pushed padding + * bytes within the skb. NULL otherwise. + */ +static char * +batadv_mcast_forw_push_padding(struct sk_buff *skb, unsigned short *tvlv_len) +{ + const int pad_len = 2; + char *padding; + + if (skb_headroom(skb) < pad_len) + return NULL; + + padding = batadv_mcast_forw_skb_push(skb, pad_len, tvlv_len); + memset(padding, 0, pad_len); + + return padding; +} + +/** + * batadv_mcast_forw_push_est_padding() - push padding bytes if necessary + * @skb: the skb to potentially push the padding onto + * @count: the (estimated) number of originators the multicast packet needs to + * be sent to + * @tvlv_len: stores the amount of currently pushed TVLV bytes + * + * If the number of destination entries is even then this adds two + * padding bytes to the end of the tracker TVLV. + * + * Return: true on success or if no padding is needed, false otherwise. + */ +static bool +batadv_mcast_forw_push_est_padding(struct sk_buff *skb, int count, + unsigned short *tvlv_len) +{ + if (!(count % 2) && !batadv_mcast_forw_push_padding(skb, tvlv_len)) + return false; + + return true; +} + +/** + * batadv_mcast_forw_orig_entry() - get orig_node from an hlist node + * @node: the hlist node to get the orig_node from + * @entry_offset: the offset of the hlist node within the orig_node struct + * + * Return: The orig_node containing the hlist node on success, NULL on error. + */ +static struct batadv_orig_node * +batadv_mcast_forw_orig_entry(struct hlist_node *node, + size_t entry_offset) +{ + /* sanity check */ + switch (entry_offset) { + case offsetof(struct batadv_orig_node, mcast_want_all_ipv4_node): + case offsetof(struct batadv_orig_node, mcast_want_all_ipv6_node): + case offsetof(struct batadv_orig_node, mcast_want_all_rtr4_node): + case offsetof(struct batadv_orig_node, mcast_want_all_rtr6_node): + break; + default: + WARN_ON(1); + return NULL; + } + + return (struct batadv_orig_node *)((void *)node - entry_offset); +} + +/** + * batadv_mcast_forw_push_dest() - push an originator MAC address onto an skb + * @bat_priv: the bat priv with all the soft interface information + * @skb: the skb to push the destination address onto + * @vid: the vlan identifier + * @orig_node: the originator node to get the MAC address from + * @num_dests: a pointer to store the number of pushed addresses in + * @tvlv_len: stores the amount of currently pushed TVLV bytes + * + * If the orig_node is a BLA backbone gateway, if there is not enough skb + * headroom available or if num_dests is already at its maximum (65535) then + * neither the skb nor num_dests is changed. Otherwise the originator's MAC + * address is pushed onto the given skb and num_dests incremented by one. + * + * Return: true if the orig_node is a backbone gateway or if an orig address + * was pushed successfully, false otherwise. + */ +static bool batadv_mcast_forw_push_dest(struct batadv_priv *bat_priv, + struct sk_buff *skb, unsigned short vid, + struct batadv_orig_node *orig_node, + unsigned short *num_dests, + unsigned short *tvlv_len) +{ + BUILD_BUG_ON(sizeof_field(struct batadv_tvlv_mcast_tracker, num_dests) + != sizeof(__be16)); + + /* Avoid sending to other BLA gateways - they already got the frame from + * the LAN side we share with them. + * TODO: Refactor to take BLA into account earlier in mode check. + */ + if (batadv_bla_is_backbone_gw_orig(bat_priv, orig_node->orig, vid)) + return true; + + if (skb_headroom(skb) < ETH_ALEN || *num_dests == U16_MAX) + return false; + + batadv_mcast_forw_skb_push(skb, ETH_ALEN, tvlv_len); + ether_addr_copy(skb->data, orig_node->orig); + (*num_dests)++; + + return true; +} + +/** + * batadv_mcast_forw_push_dests_list() - push originators from list onto an skb + * @bat_priv: the bat priv with all the soft interface information + * @skb: the skb to push the destination addresses onto + * @vid: the vlan identifier + * @head: the list to gather originators from + * @entry_offset: offset of an hlist node in an orig_node structure + * @num_dests: a pointer to store the number of pushed addresses in + * @tvlv_len: stores the amount of currently pushed TVLV bytes + * + * Push the MAC addresses of all originators in the given list onto the given + * skb. + * + * Return: true on success, false otherwise. + */ +static int batadv_mcast_forw_push_dests_list(struct batadv_priv *bat_priv, + struct sk_buff *skb, + unsigned short vid, + struct hlist_head *head, + size_t entry_offset, + unsigned short *num_dests, + unsigned short *tvlv_len) +{ + struct hlist_node *node; + struct batadv_orig_node *orig_node; + + rcu_read_lock(); + __hlist_for_each_rcu(node, head) { + orig_node = batadv_mcast_forw_orig_entry(node, entry_offset); + if (!orig_node || + !batadv_mcast_forw_push_dest(bat_priv, skb, vid, orig_node, + num_dests, tvlv_len)) { + rcu_read_unlock(); + return false; + } + } + rcu_read_unlock(); + + return true; +} + +/** + * batadv_mcast_forw_push_tt() - push originators with interest through TT + * @bat_priv: the bat priv with all the soft interface information + * @skb: the skb to push the destination addresses onto + * @vid: the vlan identifier + * @num_dests: a pointer to store the number of pushed addresses in + * @tvlv_len: stores the amount of currently pushed TVLV bytes + * + * Push the MAC addresses of all originators which have indicated interest in + * this multicast packet through the translation table onto the given skb. + * + * Return: true on success, false otherwise. + */ +static bool +batadv_mcast_forw_push_tt(struct batadv_priv *bat_priv, struct sk_buff *skb, + unsigned short vid, unsigned short *num_dests, + unsigned short *tvlv_len) +{ + struct batadv_tt_orig_list_entry *orig_entry; + + struct batadv_tt_global_entry *tt_global; + const u8 *addr = eth_hdr(skb)->h_dest; + + /* ok */ + int ret = true; + + tt_global = batadv_tt_global_hash_find(bat_priv, addr, vid); + if (!tt_global) + goto out; + + rcu_read_lock(); + hlist_for_each_entry_rcu(orig_entry, &tt_global->orig_list, list) { + if (!batadv_mcast_forw_push_dest(bat_priv, skb, vid, + orig_entry->orig_node, + num_dests, tvlv_len)) { + ret = false; + break; + } + } + rcu_read_unlock(); + + batadv_tt_global_entry_put(tt_global); + +out: + return ret; +} + +/** + * batadv_mcast_forw_push_want_all() - push originators with want-all flag + * @bat_priv: the bat priv with all the soft interface information + * @skb: the skb to push the destination addresses onto + * @vid: the vlan identifier + * @num_dests: a pointer to store the number of pushed addresses in + * @tvlv_len: stores the amount of currently pushed TVLV bytes + * + * Push the MAC addresses of all originators which have indicated interest in + * this multicast packet through the want-all flag onto the given skb. + * + * Return: true on success, false otherwise. + */ +static bool batadv_mcast_forw_push_want_all(struct batadv_priv *bat_priv, + struct sk_buff *skb, + unsigned short vid, + unsigned short *num_dests, + unsigned short *tvlv_len) +{ + struct hlist_head *head = NULL; + size_t offset; + int ret; + + switch (eth_hdr(skb)->h_proto) { + case htons(ETH_P_IP): + head = &bat_priv->mcast.want_all_ipv4_list; + offset = offsetof(struct batadv_orig_node, + mcast_want_all_ipv4_node); + break; + case htons(ETH_P_IPV6): + head = &bat_priv->mcast.want_all_ipv6_list; + offset = offsetof(struct batadv_orig_node, + mcast_want_all_ipv6_node); + break; + default: + return false; + } + + ret = batadv_mcast_forw_push_dests_list(bat_priv, skb, vid, head, + offset, num_dests, tvlv_len); + if (!ret) + return false; + + return true; +} + +/** + * batadv_mcast_forw_push_want_rtr() - push originators with want-router flag + * @bat_priv: the bat priv with all the soft interface information + * @skb: the skb to push the destination addresses onto + * @vid: the vlan identifier + * @num_dests: a pointer to store the number of pushed addresses in + * @tvlv_len: stores the amount of currently pushed TVLV bytes + * + * Push the MAC addresses of all originators which have indicated interest in + * this multicast packet through the want-all-rtr flag onto the given skb. + * + * Return: true on success, false otherwise. + */ +static bool batadv_mcast_forw_push_want_rtr(struct batadv_priv *bat_priv, + struct sk_buff *skb, + unsigned short vid, + unsigned short *num_dests, + unsigned short *tvlv_len) +{ + struct hlist_head *head = NULL; + size_t offset; + int ret; + + switch (eth_hdr(skb)->h_proto) { + case htons(ETH_P_IP): + head = &bat_priv->mcast.want_all_rtr4_list; + offset = offsetof(struct batadv_orig_node, + mcast_want_all_rtr4_node); + break; + case htons(ETH_P_IPV6): + head = &bat_priv->mcast.want_all_rtr6_list; + offset = offsetof(struct batadv_orig_node, + mcast_want_all_rtr6_node); + break; + default: + return false; + } + + ret = batadv_mcast_forw_push_dests_list(bat_priv, skb, vid, head, + offset, num_dests, tvlv_len); + if (!ret) + return false; + + return true; +} + +/** + * batadv_mcast_forw_scrape() - remove bytes within skb data + * @skb: the skb to remove bytes from + * @offset: the offset from the skb data from which to scrape + * @len: the amount of bytes to scrape starting from the offset + * + * Scrapes/removes len bytes from the given skb at the given offset from the + * skb data. + * + * Caller needs to ensure that the region from the skb data's start up + * to/including the to be removed bytes are linearized. + */ +static void batadv_mcast_forw_scrape(struct sk_buff *skb, + unsigned short offset, + unsigned short len) +{ + char *to = skb_pull(skb, len), *from = to - len; + + memmove(to, from, offset); +} + +/** + * batadv_mcast_forw_push_scrape_padding() - remove TVLV padding + * @skb: the skb to potentially adjust the TVLV's padding on + * @tvlv_len: stores the amount of currently pushed TVLV bytes + * + * Remove two padding bytes from the end of the multicast tracker TVLV, + * from before the payload data. + * + * Caller needs to ensure that the TVLV bytes are linearized. + */ +static void batadv_mcast_forw_push_scrape_padding(struct sk_buff *skb, + unsigned short *tvlv_len) +{ + const int pad_len = 2; + + batadv_mcast_forw_scrape(skb, *tvlv_len - pad_len, pad_len); + *tvlv_len -= pad_len; +} + +/** + * batadv_mcast_forw_push_insert_padding() - insert TVLV padding + * @skb: the skb to potentially adjust the TVLV's padding on + * @tvlv_len: stores the amount of currently pushed TVLV bytes + * + * Inserts two padding bytes at the end of the multicast tracker TVLV, + * before the payload data in the given skb. + * + * Return: true on success, false otherwise. + */ +static bool batadv_mcast_forw_push_insert_padding(struct sk_buff *skb, + unsigned short *tvlv_len) +{ + unsigned short offset = *tvlv_len; + char *to, *from = skb->data; + + to = batadv_mcast_forw_push_padding(skb, tvlv_len); + if (!to) + return false; + + memmove(to, from, offset); + memset(to + offset, 0, *tvlv_len - offset); + return true; +} + +/** + * batadv_mcast_forw_push_adjust_padding() - adjust padding if necessary + * @skb: the skb to potentially adjust the TVLV's padding on + * @count: the (estimated) number of originators the multicast packet needs to + * be sent to + * @tvlv_len: stores the amount of currently pushed TVLV bytes + * + * If the number of destination entries is even then this adds two + * padding bytes to the end of the tracker TVLV. + * + * Return: true on success or if no padding is needed, false otherwise. + */ +static bool +batadv_mcast_forw_push_adjust_padding(struct sk_buff *skb, int *count, + unsigned short num_dests_pushed, + unsigned short *tvlv_len) +{ + int ret = true; + + if (likely((num_dests_pushed % 2) == (*count % 2))) + goto out; + + /** + * estimated even number of destinations, but turned out to be odd + * -> remove padding + */ + if (!(*count % 2) && (num_dests_pushed % 2)) + batadv_mcast_forw_push_scrape_padding(skb, tvlv_len); + /** + * estimated odd number of destinations, but turned out to be even + * -> add padding + */ + else if ((*count % 2) && (!(num_dests_pushed % 2))) + ret = batadv_mcast_forw_push_insert_padding(skb, tvlv_len); + +out: + *count = num_dests_pushed; + return ret; +} + +/** + * batadv_mcast_forw_push_dests() - push originator addresses onto an skb + * @bat_priv: the bat priv with all the soft interface information + * @skb: the skb to push the destination addresses onto + * @vid: the vlan identifier + * @is_routable: indicates whether the destination is routable + * @count: the number of originators the multicast packet needs to be sent to + * @tvlv_len: stores the amount of currently pushed TVLV bytes + * + * Push the MAC addresses of all originators which have indicated interest in + * this multicast packet onto the given skb. + * + * Return: -ENOMEM if there is not enough skb headroom available. Otherwise, on + * success 0. + */ +static int +batadv_mcast_forw_push_dests(struct batadv_priv *bat_priv, struct sk_buff *skb, + unsigned short vid, int is_routable, int *count, + unsigned short *tvlv_len) +{ + unsigned short num_dests = 0; + + if (!batadv_mcast_forw_push_est_padding(skb, *count, tvlv_len)) + goto err; + + if (!batadv_mcast_forw_push_tt(bat_priv, skb, vid, &num_dests, + tvlv_len)) + goto err; + + if (!batadv_mcast_forw_push_want_all(bat_priv, skb, vid, &num_dests, + tvlv_len)) + goto err; + + if (is_routable && + !batadv_mcast_forw_push_want_rtr(bat_priv, skb, vid, &num_dests, + tvlv_len)) + goto err; + + if (!batadv_mcast_forw_push_adjust_padding(skb, count, num_dests, + tvlv_len)) + goto err; + + return 0; +err: + return -ENOMEM; +} + +/** + * batadv_mcast_forw_push_tracker() - push a multicast tracker TVLV header + * @skb: the skb to push the tracker TVLV onto + * @num_dests: the number of destination addresses to set in the header + * @tvlv_len: stores the amount of currently pushed TVLV bytes + * + * Pushes a multicast tracker TVLV header onto the given skb, including the + * generic TVLV header but excluding the destination MAC addresses. + * + * The provided num_dests value is taken into consideration to set the + * num_dests field in the tracker header and to set the appropriate TVLV length + * value fields. + * + * Return: -ENOMEM if there is not enough skb headroom available. Otherwise, on + * success 0. + */ +static int batadv_mcast_forw_push_tracker(struct sk_buff *skb, int num_dests, + unsigned short *tvlv_len) +{ + struct batadv_tvlv_mcast_tracker *mcast_tracker; + struct batadv_tvlv_hdr *tvlv_hdr; + unsigned int tvlv_value_len; + + if (skb_headroom(skb) < sizeof(*mcast_tracker) + sizeof(*tvlv_hdr)) + return -ENOMEM; + + tvlv_value_len = sizeof(*mcast_tracker) + *tvlv_len; + if (tvlv_value_len + sizeof(*tvlv_hdr) > U16_MAX) + return -ENOMEM; + + batadv_mcast_forw_skb_push(skb, sizeof(*mcast_tracker), tvlv_len); + mcast_tracker = (struct batadv_tvlv_mcast_tracker *)skb->data; + mcast_tracker->num_dests = htons(num_dests); + + skb_reset_network_header(skb); + + batadv_mcast_forw_skb_push(skb, sizeof(*tvlv_hdr), tvlv_len); + tvlv_hdr = (struct batadv_tvlv_hdr *)skb->data; + tvlv_hdr->type = BATADV_TVLV_MCAST_TRACKER; + tvlv_hdr->version = 1; + tvlv_hdr->len = htons(tvlv_value_len); + + return 0; +} + +/** + * batadv_mcast_forw_push_tvlvs() - push a multicast tracker TVLV onto an skb + * @bat_priv: the bat priv with all the soft interface information + * @skb: the skb to push the tracker TVLV onto + * @vid: the vlan identifier + * @is_routable: indicates whether the destination is routable + * @count: the number of originators the multicast packet needs to be sent to + * @tvlv_len: stores the amount of currently pushed TVLV bytes + * + * Pushes a multicast tracker TVLV onto the given skb, including the collected + * destination MAC addresses and the generic TVLV header. + * + * Return: -ENOMEM if there is not enough skb headroom available. Otherwise, on + * success 0. + */ +static int +batadv_mcast_forw_push_tvlvs(struct batadv_priv *bat_priv, struct sk_buff *skb, + unsigned short vid, int is_routable, int count, + unsigned short *tvlv_len) +{ + int ret; + + ret = batadv_mcast_forw_push_dests(bat_priv, skb, vid, is_routable, + &count, tvlv_len); + if (ret < 0) + return ret; + + ret = batadv_mcast_forw_push_tracker(skb, count, tvlv_len); + if (ret < 0) + return ret; + + return 0; +} + +/** + * batadv_mcast_forw_push_hdr() - push a multicast packet header onto an skb + * @skb: the skb to push the header onto + * @tvlv_len: the total TVLV length value to set in the header + * + * Pushes a batman-adv multicast packet header onto the given skb and sets + * the provided total TVLV length value in it. + * + * Caller needs to ensure enough skb headroom is available. + * + * Return: -ENOMEM if there is not enough skb headroom available. Otherwise, on + * success 0. + */ +static int +batadv_mcast_forw_push_hdr(struct sk_buff *skb, unsigned short tvlv_len) +{ + struct batadv_mcast_packet *mcast_packet; + + if (skb_headroom(skb) < sizeof(*mcast_packet)) + return -ENOMEM; + + skb_push(skb, sizeof(*mcast_packet)); + + mcast_packet = (struct batadv_mcast_packet *)skb->data; + mcast_packet->version = BATADV_COMPAT_VERSION; + mcast_packet->ttl = BATADV_TTL; + mcast_packet->packet_type = BATADV_MCAST; + mcast_packet->reserved = 0; + mcast_packet->tvlv_len = htons(tvlv_len); + + return 0; +} + /** * batadv_mcast_forw_orig_to_neigh() - get next hop neighbor to an orig address * @bat_priv: the bat priv with all the soft interface information @@ -254,3 +842,130 @@ int batadv_mcast_forw_tracker_tvlv_handler(struct batadv_priv *bat_priv, { return batadv_mcast_forw_packet(bat_priv, skb, false); } + +/** + * batadv_mcast_forw_packet_hdrlen() - multicast packet header length + * @num_dests: number of destination nodes + * + * Calculates the total batman-adv multicast packet header length for a given + * number of destination nodes (excluding the outer ethernet frame). + * + * Return: The calculated total batman-adv multicast packet header length. + */ +unsigned int batadv_mcast_forw_packet_hdrlen(unsigned int num_dests) +{ + /** + * If the number of destination entries is even then we need to add + * two byte padding to the tracker TVLV. + */ + int padding = (!(num_dests % 2)) ? 2 : 0; + + return padding + num_dests * ETH_ALEN + + sizeof(struct batadv_tvlv_mcast_tracker) + + sizeof(struct batadv_tvlv_hdr) + + sizeof(struct batadv_mcast_packet); +} + +/** + * batadv_mcast_forw_expand_head() - expand headroom for an mcast packet + * @bat_priv: the bat priv with all the soft interface information + * @skb: the multicast packet to send + * + * Tries to expand an skb's headroom so that its head to tail is 1298 + * bytes (minimum IPv6 MTU + vlan ethernet header size) large. + * + * Return: -EINVAL if the given skb's length is too large or -ENOMEM on memory + * allocation failure. Otherwise, on success, zero is returned. + */ +static int batadv_mcast_forw_expand_head(struct batadv_priv *bat_priv, + struct sk_buff *skb) +{ + int hdr_size = VLAN_ETH_HLEN + IPV6_MIN_MTU - skb->len; + + /* TODO: Could be tightened to actual number of destination nodes? + * But it's tricky, number of destinations might have increased since + * we last checked. + */ + if (hdr_size < 0) { + /* batadv_mcast_forw_mode_check_count() should ensure we do not + * end up here + */ + WARN_ON(1); + return -EINVAL; + } + + if (skb_headroom(skb) < hdr_size && + pskb_expand_head(skb, hdr_size, 0, GFP_ATOMIC) < 0) + return -ENOMEM; + + return 0; +} + +/** + * batadv_mcast_forw_push() - encapsulate skb in a batman-adv multicast packet + * @bat_priv: the bat priv with all the soft interface information + * @skb: the multicast packet to encapsulate and send + * @vid: the vlan identifier + * @is_routable: indicates whether the destination is routable + * @count: the number of originators the multicast packet needs to be sent to + * + * Encapsulates the given multicast packet in a batman-adv multicast packet. + * A multicast tracker TVLV with destination originator addresses for any node + * that signaled interest in it, that is either via the translation table or the + * according want-all flags, is attached accordingly. + * + * Return: true on success, false otherwise. + */ +bool batadv_mcast_forw_push(struct batadv_priv *bat_priv, struct sk_buff *skb, + unsigned short vid, int is_routable, int count) +{ + unsigned short tvlv_len = 0; + int ret; + + if (batadv_mcast_forw_expand_head(bat_priv, skb) < 0) + goto err; + + skb_reset_transport_header(skb); + + ret = batadv_mcast_forw_push_tvlvs(bat_priv, skb, vid, is_routable, + count, &tvlv_len); + if (ret < 0) + goto err; + + ret = batadv_mcast_forw_push_hdr(skb, tvlv_len); + if (ret < 0) + goto err; + + return true; + +err: + if (tvlv_len) + skb_pull(skb, tvlv_len); + + return false; +} + +/** + * batadv_mcast_forw_mcsend() - send a self prepared batman-adv multicast packet + * @bat_priv: the bat priv with all the soft interface information + * @skb: the multicast packet to encapsulate and send + * + * Transmits a batman-adv multicast packet that was locally prepared and + * consumes/frees it. + * + * Return: NET_XMIT_DROP on memory allocation failure. NET_XMIT_SUCCESS + * otherwise. + */ +int batadv_mcast_forw_mcsend(struct batadv_priv *bat_priv, + struct sk_buff *skb) +{ + int ret = batadv_mcast_forw_packet(bat_priv, skb, true); + + if (ret < 0) { + kfree_skb(skb); + return NET_XMIT_DROP; + } + + consume_skb(skb); + return NET_XMIT_SUCCESS; +} diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c index 72b7120e4629..5b9be365b706 100644 --- a/net/batman-adv/soft-interface.c +++ b/net/batman-adv/soft-interface.c @@ -298,12 +298,13 @@ static netdev_tx_t batadv_interface_tx(struct sk_buff *skb,

send: if (do_bcast && !is_broadcast_ether_addr(ethhdr->h_dest)) { - forw_mode = batadv_mcast_forw_mode(bat_priv, skb, + forw_mode = batadv_mcast_forw_mode(bat_priv, skb, vid, &mcast_is_routable); switch (forw_mode) { case BATADV_FORW_BCAST: break; case BATADV_FORW_UCASTS: + case BATADV_FORW_MCAST: do_bcast = false; break; case BATADV_FORW_NONE: @@ -362,6 +363,8 @@ static netdev_tx_t batadv_interface_tx(struct sk_buff *skb, } else if (forw_mode == BATADV_FORW_UCASTS) { ret = batadv_mcast_forw_send(bat_priv, skb, vid, mcast_is_routable); + } else if (forw_mode == BATADV_FORW_MCAST) { + ret = batadv_mcast_forw_mcsend(bat_priv, skb); } else { if (batadv_dat_snoop_outgoing_arp_request(bat_priv, skb)) @@ -759,6 +762,7 @@ static int batadv_softif_init_late(struct net_device *dev) atomic_set(&bat_priv->mcast.num_want_all_unsnoopables, 0); atomic_set(&bat_priv->mcast.num_want_all_ipv4, 0); atomic_set(&bat_priv->mcast.num_want_all_ipv6, 0); + atomic_set(&bat_priv->mcast.num_no_mc_ptype_capa, 0); #endif atomic_set(&bat_priv->gw.mode, BATADV_GW_MODE_OFF); atomic_set(&bat_priv->gw.bandwidth_down, 100); diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h index a2fee3325b29..4008ae1d6c15 100644 --- a/net/batman-adv/types.h +++ b/net/batman-adv/types.h @@ -1342,6 +1342,12 @@ struct batadv_priv_mcast { /** @num_want_all_rtr6: counter for items in want_all_rtr6_list */ atomic_t num_want_all_rtr6;

+ /** + * @num_no_mc_ptype_capa: counter for number of nodes without the + * BATADV_MCAST_HAVE_MC_PTYPE_CAPA flag + */ + atomic_t num_no_mc_ptype_capa; + /** * @want_lists_lock: lock for protecting modifications to mcasts * want_all_{unsnoopables,ipv4,ipv6}_list (traversals are rcu-locked)

On Saturday, 8 July 2023 23:51:10 CEST Linus Lüssing wrote: [...]

Changelog v5:

• removed patches 1/5 + 2/5, as they were already applied
• rebased to current main branch
• changed padding behaviour:
  • now 2 bytes padding on the end of the multicast tracker TVLV, if number of destination nodes is even
  • as number of destination nodes might change between initial check until after pushing them, functions to post-adjust padding after pushing were added
• added/fixed TTL handling
• removed skb_pull() bailing from sub-functions of batadv_mcast_forw_push(), to only have a single skb_pull() to keep track of in batadv_mcast_forw_push() to revert the changes to the skb; instead a "unsigned short *tvlv_len" is passsed along in batadv_mcast_.*push.*() functions to keep track of how many bytes were pushed
• moved + verified skb->ip_summed invalidation
• batadv_mcast_forw_shrink_tracker() xmas tree ordering
• reword batadv_mcast_forw_push_dest() "Return:" kerneldoc
• fixed spelling: outter -> outer

Didn't perform any actual review. But here are the buildbot complaints. The compiler.h is missing since patch 2 (for the "likely()").

Output of different failed tests ================================

ecsv/multicast: headers -----------------------

diff --git a/net/batman-adv/multicast_forw.c b/net/batman-adv/multicast_forw.c index a90e9057..96ec3f06 100644 --- a/net/batman-adv/multicast_forw.c +++ b/net/batman-adv/multicast_forw.c @@ -10,6 +10,7 @@ #include <linux/bug.h> #include <linux/build_bug.h> #include <linux/byteorder/generic.h> +#include <linux/compiler.h> #include <linux/errno.h> #include <linux/etherdevice.h> #include <linux/gfp.h>

ecsv/multicast: kerneldoc ./net/batman-adv/multicast_forw.c -----------------------------------------------------------

./net/batman-adv/multicast_forw.c:433: warning: Function parameter or member 'num_dests_pushed' not described in 'batadv_mcast_forw_push_adjust_padding'

ecsv/multicast: sparse linux-5.1 cfg: BLA=y DAT=n DEBUG=n TRACING=y NC=y MCAST=y BATMAN_V=y ---------------------------------------------------------------------------

/home/build_test/build_env/tmp.SpMnhX4MAz/net/batman-adv/multicast_forw.c:783:7: warning: symbol 'batadv_mcast_forw_shrink_align_offset' was not declared. Should it be static?

ecsv/multicast: unused_symbols linux-5.1 cfg: BLA=y DAT=n DEBUG=n TRACING=y NC=y MCAST=y BATMAN_V=y ---------------------------------------------------------------------------

batadv_mcast_forw_shrink_align_offset

Kind regards, Sven