[v7,4/4] batman-adv: Add IPv4 link-local/IPv6-ll-all-nodes multicast support
Commit Message
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_HAS_NO_BRIDGE 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 and the BATADV_MCAST_LISTENER_ANNOUNCEMENT
flag are currently set and unset at the same time, so 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 will need only
one node with a bridge to disable optimizations for link-local IPv4
and IPv6-link-local-all-nodes multicast, resulting in flooding all
these packets again. So the 224.0.0.x address range and the ff02::1
address will never be a safe choice for multicast streaming etc. if
you do not control every node.
Signed-off-by: Linus Lüssing <linus.luessing@web.de>
---
main.h | 1 +
multicast.c | 170 ++++++++++++++++++++++++++++++++++++++++++++----------
packet.h | 1 +
soft-interface.c | 1 +
types.h | 1 +
5 files changed, 143 insertions(+), 31 deletions(-)
Comments
On Thu, Jul 04, 2013 at 12:03:22AM +0200, Linus Lüssing wrote:
> [...]
> +enum batadv_forw_mode
> +batadv_mcast_forw_mode(struct sk_buff *skb, struct batadv_priv *bat_priv)
> +{
> + struct ethhdr *ethhdr = (struct ethhdr *)(skb->data);
> + int ret;
> +
> + ret = batadv_mcast_forw_mode_check(skb, bat_priv);
> + if (ret == -ENOMEM)
> + return BATADV_FORW_NONE;
> + else if (ret == -EINVAL)
Shouldn't this better be "ret < 0", in case you add more error cases later?
> return BATADV_FORW_ALL;
>
> - count = batadv_tt_global_hash_count(bat_priv, ethhdr->h_dest,
> + ret = batadv_tt_global_hash_count(bat_priv, ethhdr->h_dest,
> BATADV_NO_FLAGS);
>
> - switch (count) {
> + switch (ret) {
> case 0:
> return BATADV_FORW_NONE;
> case 1:
> @@ -263,6 +348,28 @@ batadv_mcast_forw_mode(struct sk_buff *skb, struct batadv_priv *bat_priv)
> }
>
> /**
> + * batadv_mcast_tvlv_update_flag_counter - update the counter of a flag
> + * @flag: the flag we want to update counters for
> + * @flag_counter: the counter we might update
> + * @new_flags: the new capability bitset of a node
> + * @old_flags: the current, to be updated bitset of a node
> + *
> + * Update the given flag_counter with the help of the new flag information
> + * of a node to reflect how many nodes have the given flag unset.
> + */
> +static void batadv_mcast_tvlv_update_flag_counter(uint8_t flag,
> + atomic_t *flag_counter,
> + uint8_t new_flags,
> + int old_flags)
Why are parts of the bitsets uint8_t, some int?
Also, this function should go into one of the previous patches, this has nothing to do with
IPv4 but is just a refactoring.
> +{
> + if (!(new_flags & flag) &&
> + (old_flags & flag || old_flags & BATADV_UNINIT_FLAGS))
> + atomic_inc(flag_counter);
> + else if (new_flags & flag && !(old_flags & flag))
> + atomic_dec(flag_counter);
> +}
> +
> +/**
> * 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
> @@ -285,13 +392,14 @@ static void batadv_mcast_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
> (tvlv_value) && (tvlv_value_len == sizeof(mcast_flags)))
> mcast_flags = *(uint8_t *)tvlv_value;
>
> - if (!(mcast_flags & BATADV_MCAST_LISTENER_ANNOUNCEMENT) &&
> - (orig->mcast_flags & BATADV_MCAST_LISTENER_ANNOUNCEMENT ||
> - orig->mcast_flags & BATADV_UNINIT_FLAGS))
> - atomic_inc(&bat_priv->mcast.num_no_mla);
> - else if (mcast_flags & BATADV_MCAST_LISTENER_ANNOUNCEMENT &&
> - !(orig->mcast_flags & BATADV_MCAST_LISTENER_ANNOUNCEMENT))
> - atomic_dec(&bat_priv->mcast.num_no_mla);
> + batadv_mcast_tvlv_update_flag_counter(
> + BATADV_MCAST_LISTENER_ANNOUNCEMENT,
> + &bat_priv->mcast.num_no_mla,
> + mcast_flags, orig->mcast_flags);
> + batadv_mcast_tvlv_update_flag_counter(
> + BATADV_MCAST_HAS_NO_BRIDGE,
> + &bat_priv->mcast.num_has_bridge,
> + mcast_flags, orig->mcast_flags);
You should find a shorter name, the alignment looks really ugly. :)
Cheers,
Simon
On Fri, Jul 12, 2013 at 11:12:16AM +0200, Simon Wunderlich wrote:
> On Thu, Jul 04, 2013 at 12:03:22AM +0200, Linus Lüssing wrote:
> > [...]
> > +enum batadv_forw_mode
> > +batadv_mcast_forw_mode(struct sk_buff *skb, struct batadv_priv *bat_priv)
> > +{
> > + struct ethhdr *ethhdr = (struct ethhdr *)(skb->data);
> > + int ret;
> > +
> > + ret = batadv_mcast_forw_mode_check(skb, bat_priv);
> > + if (ret == -ENOMEM)
> > + return BATADV_FORW_NONE;
> > + else if (ret == -EINVAL)
>
> Shouldn't this better be "ret < 0", in case you add more error cases later?
Good idea! Looks better, I'm adding that.
>
> > return BATADV_FORW_ALL;
> >
> > - count = batadv_tt_global_hash_count(bat_priv, ethhdr->h_dest,
> > + ret = batadv_tt_global_hash_count(bat_priv, ethhdr->h_dest,
> > BATADV_NO_FLAGS);
> >
> > - switch (count) {
> > + switch (ret) {
> > case 0:
> > return BATADV_FORW_NONE;
> > case 1:
> > @@ -263,6 +348,28 @@ batadv_mcast_forw_mode(struct sk_buff *skb, struct batadv_priv *bat_priv)
> > }
> >
> > /**
> > + * batadv_mcast_tvlv_update_flag_counter - update the counter of a flag
> > + * @flag: the flag we want to update counters for
> > + * @flag_counter: the counter we might update
> > + * @new_flags: the new capability bitset of a node
> > + * @old_flags: the current, to be updated bitset of a node
> > + *
> > + * Update the given flag_counter with the help of the new flag information
> > + * of a node to reflect how many nodes have the given flag unset.
> > + */
> > +static void batadv_mcast_tvlv_update_flag_counter(uint8_t flag,
> > + atomic_t *flag_counter,
> > + uint8_t new_flags,
> > + int old_flags)
>
> Why are parts of the bitsets uint8_t, some int?
Because the locally stored mcast_flags variable is bigger than the tvlv
mcast_flags (because of the BATADV_UNINIT_FLAGS).
>
> Also, this function should go into one of the previous patches, this has nothing to do with
> IPv4 but is just a refactoring.
Hm, it's just moving some code to a new function because the
original function got too long for my taste now. Anyways, ok, I'm
going to introduce that function in the previous patch already.
>
> > +{
> > + if (!(new_flags & flag) &&
> > + (old_flags & flag || old_flags & BATADV_UNINIT_FLAGS))
> > + atomic_inc(flag_counter);
> > + else if (new_flags & flag && !(old_flags & flag))
> > + atomic_dec(flag_counter);
> > +}
> > +
> > +/**
> > * 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
> > @@ -285,13 +392,14 @@ static void batadv_mcast_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
> > (tvlv_value) && (tvlv_value_len == sizeof(mcast_flags)))
> > mcast_flags = *(uint8_t *)tvlv_value;
> >
> > - if (!(mcast_flags & BATADV_MCAST_LISTENER_ANNOUNCEMENT) &&
> > - (orig->mcast_flags & BATADV_MCAST_LISTENER_ANNOUNCEMENT ||
> > - orig->mcast_flags & BATADV_UNINIT_FLAGS))
> > - atomic_inc(&bat_priv->mcast.num_no_mla);
> > - else if (mcast_flags & BATADV_MCAST_LISTENER_ANNOUNCEMENT &&
> > - !(orig->mcast_flags & BATADV_MCAST_LISTENER_ANNOUNCEMENT))
> > - atomic_dec(&bat_priv->mcast.num_no_mla);
> > + batadv_mcast_tvlv_update_flag_counter(
> > + BATADV_MCAST_LISTENER_ANNOUNCEMENT,
> > + &bat_priv->mcast.num_no_mla,
> > + mcast_flags, orig->mcast_flags);
> > + batadv_mcast_tvlv_update_flag_counter(
> > + BATADV_MCAST_HAS_NO_BRIDGE,
> > + &bat_priv->mcast.num_has_bridge,
> > + mcast_flags, orig->mcast_flags);
>
> You should find a shorter name, the alignment looks really ugly. :)
Oki doki, fair point :).
>
> Cheers,
> Simon
Cheers, Linus
@@ -166,6 +166,7 @@ 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>
@@ -208,31 +208,61 @@ out:
}
/**
- * batadv_mcast_forw_mode - check on how to forward a multicast packet
- * @skb: The multicast packet to check
+ * batadv_mcast_forw_mode_check_ipv4 - check for optimized forwarding potential
+ * @skb: the IPv4 packet to check
* @bat_priv: the bat priv with all the soft interface information
*
- * Return the forwarding mode as enum batadv_forw_mode.
+ * 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 sk_buff *skb,
+ struct batadv_priv *bat_priv)
+{
+ 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, then add
+ * scope >= link local, too
+ */
+ if (!ipv4_is_local_multicast(iphdr->daddr))
+ return -EINVAL;
+
+ /* With one bridge involved, we cannot be certain about
+ * link-local multicast listener announcements anymore
+ */
+ if (atomic_read(&bat_priv->mcast.num_has_bridge))
+ return -EINVAL;
+
+ return 0;
+}
+
+/**
+ * batadv_mcast_forw_mode_check_ipv6 - check for optimized forwarding potential
+ * @skb: the IPv6 packet to check
+ * @bat_priv: the bat priv with all the soft interface information
+ *
+ * Check whether the given IPv6 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.
*/
-enum batadv_forw_mode
-batadv_mcast_forw_mode(struct sk_buff *skb, struct batadv_priv *bat_priv)
+static int batadv_mcast_forw_mode_check_ipv6(struct sk_buff *skb,
+ struct batadv_priv *bat_priv)
{
- struct ethhdr *ethhdr = (struct ethhdr *)(skb->data);
struct ipv6hdr *ip6hdr;
- int count;
-
- if (!atomic_read(&bat_priv->multicast_mode))
- return BATADV_FORW_ALL;
-
- if (atomic_read(&bat_priv->mcast.num_no_mla))
- return BATADV_FORW_ALL;
-
- if (ntohs(ethhdr->h_proto) != ETH_P_IPV6)
- return BATADV_FORW_ALL;
/* We might fail due to out-of-memory -> drop it */
- if (!pskb_may_pull(skb, sizeof(*ethhdr) + sizeof(*ip6hdr)))
- return BATADV_FORW_NONE;
+ if (!pskb_may_pull(skb, sizeof(struct ethhdr) + sizeof(*ip6hdr)))
+ return -ENOMEM;
ip6hdr = ipv6_hdr(skb);
@@ -241,18 +271,73 @@ batadv_mcast_forw_mode(struct sk_buff *skb, struct batadv_priv *bat_priv)
*/
if (IPV6_ADDR_MC_SCOPE(&ip6hdr->daddr) !=
IPV6_ADDR_SCOPE_LINKLOCAL)
- return BATADV_FORW_ALL;
+ return -EINVAL;
- /* We cannot snoop and therefore cannot optimize the
- * all-nodes-multicast address
+ /* With one bridge involved, we cannot be certain about
+ * link-local-all-nodes multicast listener announcements anymore
*/
- if (ipv6_addr_is_ll_all_nodes(&ip6hdr->daddr))
+ if (ipv6_addr_is_ll_all_nodes(&ip6hdr->daddr) &&
+ atomic_read(&bat_priv->mcast.num_has_bridge))
+ return -EINVAL;
+
+ return 0;
+}
+
+/**
+ * batadv_mcast_forw_mode_check - check for optimized forwarding potential
+ * @skb: the multicast frame to check
+ * @bat_priv: the bat priv with all the soft interface information
+ *
+ * Check whether the given multicast ethernet frame 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(struct sk_buff *skb,
+ struct batadv_priv *bat_priv)
+{
+ struct ethhdr *ethhdr = (struct ethhdr *)(skb->data);
+
+ if (!atomic_read(&bat_priv->multicast_mode))
+ return -EINVAL;
+
+ if (atomic_read(&bat_priv->mcast.num_no_mla))
+ return -EINVAL;
+
+ switch (ntohs(ethhdr->h_proto)) {
+ case ETH_P_IP:
+ return batadv_mcast_forw_mode_check_ipv4(skb, bat_priv);
+ case ETH_P_IPV6:
+ return batadv_mcast_forw_mode_check_ipv6(skb, bat_priv);
+ default:
+ return -EINVAL;
+ }
+}
+
+/**
+ * batadv_mcast_forw_mode - check on how to forward a multicast packet
+ * @skb: The multicast packet to check
+ * @bat_priv: the bat priv with all the soft interface information
+ *
+ * Return the forwarding mode as enum batadv_forw_mode.
+ */
+enum batadv_forw_mode
+batadv_mcast_forw_mode(struct sk_buff *skb, struct batadv_priv *bat_priv)
+{
+ struct ethhdr *ethhdr = (struct ethhdr *)(skb->data);
+ int ret;
+
+ ret = batadv_mcast_forw_mode_check(skb, bat_priv);
+ if (ret == -ENOMEM)
+ return BATADV_FORW_NONE;
+ else if (ret == -EINVAL)
return BATADV_FORW_ALL;
- count = batadv_tt_global_hash_count(bat_priv, ethhdr->h_dest,
+ ret = batadv_tt_global_hash_count(bat_priv, ethhdr->h_dest,
BATADV_NO_FLAGS);
- switch (count) {
+ switch (ret) {
case 0:
return BATADV_FORW_NONE;
case 1:
@@ -263,6 +348,28 @@ batadv_mcast_forw_mode(struct sk_buff *skb, struct batadv_priv *bat_priv)
}
/**
+ * batadv_mcast_tvlv_update_flag_counter - update the counter of a flag
+ * @flag: the flag we want to update counters for
+ * @flag_counter: the counter we might update
+ * @new_flags: the new capability bitset of a node
+ * @old_flags: the current, to be updated bitset of a node
+ *
+ * Update the given flag_counter with the help of the new flag information
+ * of a node to reflect how many nodes have the given flag unset.
+ */
+static void batadv_mcast_tvlv_update_flag_counter(uint8_t flag,
+ atomic_t *flag_counter,
+ uint8_t new_flags,
+ int old_flags)
+{
+ if (!(new_flags & flag) &&
+ (old_flags & flag || old_flags & BATADV_UNINIT_FLAGS))
+ atomic_inc(flag_counter);
+ else if (new_flags & flag && !(old_flags & flag))
+ atomic_dec(flag_counter);
+}
+
+/**
* 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
@@ -285,13 +392,14 @@ static void batadv_mcast_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
(tvlv_value) && (tvlv_value_len == sizeof(mcast_flags)))
mcast_flags = *(uint8_t *)tvlv_value;
- if (!(mcast_flags & BATADV_MCAST_LISTENER_ANNOUNCEMENT) &&
- (orig->mcast_flags & BATADV_MCAST_LISTENER_ANNOUNCEMENT ||
- orig->mcast_flags & BATADV_UNINIT_FLAGS))
- atomic_inc(&bat_priv->mcast.num_no_mla);
- else if (mcast_flags & BATADV_MCAST_LISTENER_ANNOUNCEMENT &&
- !(orig->mcast_flags & BATADV_MCAST_LISTENER_ANNOUNCEMENT))
- atomic_dec(&bat_priv->mcast.num_no_mla);
+ batadv_mcast_tvlv_update_flag_counter(
+ BATADV_MCAST_LISTENER_ANNOUNCEMENT,
+ &bat_priv->mcast.num_no_mla,
+ mcast_flags, orig->mcast_flags);
+ batadv_mcast_tvlv_update_flag_counter(
+ BATADV_MCAST_HAS_NO_BRIDGE,
+ &bat_priv->mcast.num_has_bridge,
+ mcast_flags, orig->mcast_flags);
orig->mcast_flags = mcast_flags;
}
@@ -94,6 +94,7 @@ enum batadv_icmp_packettype {
/* multicast capabilities */
enum batadv_mcast_flags {
BATADV_MCAST_LISTENER_ANNOUNCEMENT = BIT(0),
+ BATADV_MCAST_HAS_NO_BRIDGE = BIT(1),
};
/* tt data subtypes */
@@ -663,6 +663,7 @@ static int batadv_softif_init_late(struct net_device *dev)
#ifdef CONFIG_BATMAN_ADV_MCAST
atomic_set(&bat_priv->multicast_mode, 1);
atomic_set(&bat_priv->mcast.num_no_mla, 0);
+ atomic_set(&bat_priv->mcast.num_has_bridge, 0);
#endif
atomic_set(&bat_priv->gw_mode, BATADV_GW_MODE_OFF);
atomic_set(&bat_priv->gw_sel_class, 20);
@@ -508,6 +508,7 @@ struct batadv_priv_dat {
struct batadv_priv_mcast {
struct hlist_head mla_list;
atomic_t num_no_mla;
+ atomic_t num_has_bridge;
};
#endif