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batman-adv: mcast: implement multicast packet generation

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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>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
This commit is contained in:
Linus Lüssing 2023-09-07 03:09:09 +02:00 committed by Simon Wunderlich
parent 07afe1ba28
commit 9003913322
5 changed files with 840 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

79
net/batman-adv/multicast.c
View File

@ -1169,17 +1169,62 @@ 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;
@ -1209,10 +1254,8 @@ 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);
}
/**
@ -1772,6 +1815,31 @@ 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
@ -1840,6 +1908,7 @@ 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);

25
net/batman-adv/multicast.h
View File

@ -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_ */

732
net/batman-adv/multicast_forw.c
View File

@ -7,19 +7,30 @@
#include "multicast.h"
#include "main.h"
#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>
#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 "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)
@ -27,6 +38,600 @@
#define batadv_mcast_forw_tracker_for_each_dest2(dest1, dest2, num_dests) \
for (; num_dests; num_dests--, (dest1) += ETH_ALEN, (dest2) += 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, *from;
SKB_LINEAR_ASSERT(skb);
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
* @num_dests_pushed: the number of originators that were actually added to the
* multicast packet's tracker TVLV
* @tvlv_len: stores the amount of currently pushed TVLV bytes
*
* Adjusts the padding in the multicast packet's tracker TVLV depending on the
* initially estimated amount of destinations versus the amount of destinations
* that were actually added to the tracker TVLV.
*
* If the initial estimate was correct or at least the oddness was the same then
* no padding adjustment is performed.
* If the initially estimated number was even, so padding was initially added,
* but it turned out to be odd then padding is removed.
* If the initially estimated number was odd, so no padding was initially added,
* but it turned out to be even then padding is added.
*
* Return: true if no padding adjustment is needed or the adjustment was
* successful, 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_scrub_dests() - scrub destinations in a tracker TVLV
* @bat_priv: the bat priv with all the soft interface information
@ -237,3 +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;
}

6
net/batman-adv/soft-interface.c
View File

@ -301,12 +301,13 @@ 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:
@ -365,6 +366,8 @@ send:
} 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))
@ -762,6 +765,7 @@ 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);

6
net/batman-adv/types.h
View File

@ -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)