From: Linus Lüssing linus.luessing@c0d3.blue
Now that we not only track the presence of multicast listeners but also multicast routers we can safely apply group-aware multicast-to-unicast forwarding to packets with a destination address of scope greater than link-local as well.
Signed-off-by: Linus Lüssing linus.luessing@c0d3.blue Signed-off-by: Sven Eckelmann sven@narfation.org Signed-off-by: Simon Wunderlich sw@simonwunderlich.de --- net/batman-adv/multicast.c | 259 +++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 241 insertions(+), 18 deletions(-)
diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c index 80d5f3c892cb..67d7f83009ae 100644 --- a/net/batman-adv/multicast.c +++ b/net/batman-adv/multicast.c @@ -980,6 +980,7 @@ static bool batadv_mcast_is_report_ipv4(struct sk_buff *skb) * @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 + * @is_routable: stores whether the destination is routable * * Checks whether the given IPv4 packet has the potential to be forwarded with a * mode more optimal than classic flooding. @@ -989,7 +990,8 @@ static bool batadv_mcast_is_report_ipv4(struct sk_buff *skb) */ static int batadv_mcast_forw_mode_check_ipv4(struct batadv_priv *bat_priv, struct sk_buff *skb, - bool *is_unsnoopable) + bool *is_unsnoopable, + int *is_routable) { struct iphdr *iphdr;
@@ -1002,16 +1004,13 @@ static int batadv_mcast_forw_mode_check_ipv4(struct batadv_priv *bat_priv,
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; + if (ipv4_is_local_multicast(iphdr->daddr)) + *is_unsnoopable = true; + else + *is_routable = ETH_P_IP;
return 0; } @@ -1046,6 +1045,7 @@ static bool batadv_mcast_is_report_ipv6(struct sk_buff *skb) * @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 + * @is_routable: stores whether the destination is routable * * Checks whether the given IPv6 packet has the potential to be forwarded with a * mode more optimal than classic flooding. @@ -1054,7 +1054,8 @@ static bool batadv_mcast_is_report_ipv6(struct sk_buff *skb) */ static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv, struct sk_buff *skb, - bool *is_unsnoopable) + bool *is_unsnoopable, + int *is_routable) { struct ipv6hdr *ip6hdr;
@@ -1067,10 +1068,7 @@ static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv,
ip6hdr = ipv6_hdr(skb);
- /* TODO: Implement Multicast Router Discovery (RFC4286), - * then allow scope > link local, too - */ - if (IPV6_ADDR_MC_SCOPE(&ip6hdr->daddr) != IPV6_ADDR_SCOPE_LINKLOCAL) + if (IPV6_ADDR_MC_SCOPE(&ip6hdr->daddr) < IPV6_ADDR_SCOPE_LINKLOCAL) return -EINVAL;
/* link-local-all-nodes multicast listeners behind a bridge are @@ -1078,6 +1076,8 @@ static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv, */ if (ipv6_addr_is_ll_all_nodes(&ip6hdr->daddr)) *is_unsnoopable = true; + else if (IPV6_ADDR_MC_SCOPE(&ip6hdr->daddr) > IPV6_ADDR_SCOPE_LINKLOCAL) + *is_routable = ETH_P_IPV6;
return 0; } @@ -1087,6 +1087,7 @@ static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv, * @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 + * @is_routable: stores whether the destination is routable * * Checks whether the given multicast ethernet frame has the potential to be * forwarded with a mode more optimal than classic flooding. @@ -1095,7 +1096,8 @@ static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv, */ static int batadv_mcast_forw_mode_check(struct batadv_priv *bat_priv, struct sk_buff *skb, - bool *is_unsnoopable) + bool *is_unsnoopable, + int *is_routable) { struct ethhdr *ethhdr = eth_hdr(skb);
@@ -1105,13 +1107,15 @@ static int batadv_mcast_forw_mode_check(struct batadv_priv *bat_priv, switch (ntohs(ethhdr->h_proto)) { case ETH_P_IP: return batadv_mcast_forw_mode_check_ipv4(bat_priv, skb, - is_unsnoopable); + is_unsnoopable, + is_routable); case ETH_P_IPV6: if (!IS_ENABLED(CONFIG_IPV6)) return -EINVAL;
return batadv_mcast_forw_mode_check_ipv6(bat_priv, skb, - is_unsnoopable); + is_unsnoopable, + is_routable); default: return -EINVAL; } @@ -1142,6 +1146,29 @@ static int batadv_mcast_forw_want_all_ip_count(struct batadv_priv *bat_priv, }
/** + * batadv_mcast_forw_rtr_count() - count nodes with a multicast router + * @bat_priv: the bat priv with all the soft interface information + * @protocol: the ethernet protocol type to count multicast routers for + * + * Return: the number of nodes which want all routable IPv4 multicast traffic + * if the protocol is ETH_P_IP or the number of nodes which want all routable + * IPv6 traffic if the protocol is ETH_P_IPV6. Otherwise returns 0. + */ + +static int batadv_mcast_forw_rtr_count(struct batadv_priv *bat_priv, + int protocol) +{ + switch (protocol) { + case ETH_P_IP: + return atomic_read(&bat_priv->mcast.num_want_all_rtr4); + case ETH_P_IPV6: + return atomic_read(&bat_priv->mcast.num_want_all_rtr6); + default: + return 0; + } +} + +/** * batadv_mcast_forw_tt_node_get() - get a multicast tt node * @bat_priv: the bat priv with all the soft interface information * @ethhdr: the ether header containing the multicast destination @@ -1263,6 +1290,84 @@ batadv_mcast_forw_unsnoop_node_get(struct batadv_priv *bat_priv) }
/** + * batadv_mcast_forw_rtr4_node_get() - get a node with an ipv4 mcast router flag + * @bat_priv: the bat priv with all the soft interface information + * + * Return: an orig_node which has the BATADV_MCAST_WANT_NO_RTR4 flag unset and + * increases its refcount. + */ +static struct batadv_orig_node * +batadv_mcast_forw_rtr4_node_get(struct batadv_priv *bat_priv) +{ + struct batadv_orig_node *tmp_orig_node, *orig_node = NULL; + + rcu_read_lock(); + hlist_for_each_entry_rcu(tmp_orig_node, + &bat_priv->mcast.want_all_rtr4_list, + mcast_want_all_rtr4_node) { + if (!kref_get_unless_zero(&tmp_orig_node->refcount)) + continue; + + orig_node = tmp_orig_node; + break; + } + rcu_read_unlock(); + + return orig_node; +} + +/** + * batadv_mcast_forw_rtr6_node_get() - get a node with an ipv6 mcast router flag + * @bat_priv: the bat priv with all the soft interface information + * + * Return: an orig_node which has the BATADV_MCAST_WANT_NO_RTR6 flag unset + * and increases its refcount. + */ +static struct batadv_orig_node * +batadv_mcast_forw_rtr6_node_get(struct batadv_priv *bat_priv) +{ + struct batadv_orig_node *tmp_orig_node, *orig_node = NULL; + + rcu_read_lock(); + hlist_for_each_entry_rcu(tmp_orig_node, + &bat_priv->mcast.want_all_rtr6_list, + mcast_want_all_rtr6_node) { + if (!kref_get_unless_zero(&tmp_orig_node->refcount)) + continue; + + orig_node = tmp_orig_node; + break; + } + rcu_read_unlock(); + + return orig_node; +} + +/** + * batadv_mcast_forw_rtr_node_get() - get a node with an ipv4/ipv6 router flag + * @bat_priv: the bat priv with all the soft interface information + * @ethhdr: an ethernet header to determine the protocol family from + * + * Return: an orig_node which has no BATADV_MCAST_WANT_NO_RTR4 or + * BATADV_MCAST_WANT_NO_RTR6 flag, depending on the provided ethhdr, set and + * increases its refcount. + */ +static struct batadv_orig_node * +batadv_mcast_forw_rtr_node_get(struct batadv_priv *bat_priv, + struct ethhdr *ethhdr) +{ + switch (ntohs(ethhdr->h_proto)) { + case ETH_P_IP: + return batadv_mcast_forw_rtr4_node_get(bat_priv); + case ETH_P_IPV6: + return batadv_mcast_forw_rtr6_node_get(bat_priv); + default: + /* we shouldn't be here... */ + return NULL; + } +} + +/** * 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 @@ -1280,8 +1385,11 @@ batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb, bool is_unsnoopable = false; unsigned int mcast_fanout; struct ethhdr *ethhdr; + int is_routable = 0; + int rtr_count = 0;
- ret = batadv_mcast_forw_mode_check(bat_priv, skb, &is_unsnoopable); + ret = batadv_mcast_forw_mode_check(bat_priv, skb, &is_unsnoopable, + &is_routable); if (ret == -ENOMEM) return BATADV_FORW_NONE; else if (ret < 0) @@ -1294,8 +1402,9 @@ batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb, ip_count = batadv_mcast_forw_want_all_ip_count(bat_priv, ethhdr); unsnoop_count = !is_unsnoopable ? 0 : atomic_read(&bat_priv->mcast.num_want_all_unsnoopables); + rtr_count = batadv_mcast_forw_rtr_count(bat_priv, is_routable);
- total_count = tt_count + ip_count + unsnoop_count; + total_count = tt_count + ip_count + unsnoop_count + rtr_count;
switch (total_count) { case 1: @@ -1305,6 +1414,9 @@ batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb, *orig = batadv_mcast_forw_ip_node_get(bat_priv, ethhdr); else if (unsnoop_count) *orig = batadv_mcast_forw_unsnoop_node_get(bat_priv); + else if (rtr_count) + *orig = batadv_mcast_forw_rtr_node_get(bat_priv, + ethhdr);
if (*orig) return BATADV_FORW_SINGLE; @@ -1476,6 +1588,111 @@ batadv_mcast_forw_want_all(struct batadv_priv *bat_priv, }
/** + * batadv_mcast_forw_want_all_rtr4() - forward to nodes with want-all-rtr4 + * @bat_priv: the bat priv with all the soft interface information + * @skb: the multicast packet to transmit + * @vid: the vlan identifier + * + * Sends copies of a frame with multicast destination to any node with a + * BATADV_MCAST_WANT_NO_RTR4 flag unset. A transmission is performed via a + * batman-adv unicast packet for each such destination node. + * + * Return: NET_XMIT_DROP on memory allocation failure, NET_XMIT_SUCCESS + * otherwise. + */ +static int +batadv_mcast_forw_want_all_rtr4(struct batadv_priv *bat_priv, + struct sk_buff *skb, unsigned short vid) +{ + struct batadv_orig_node *orig_node; + int ret = NET_XMIT_SUCCESS; + struct sk_buff *newskb; + + rcu_read_lock(); + hlist_for_each_entry_rcu(orig_node, + &bat_priv->mcast.want_all_rtr4_list, + mcast_want_all_rtr4_node) { + newskb = skb_copy(skb, GFP_ATOMIC); + if (!newskb) { + ret = NET_XMIT_DROP; + break; + } + + batadv_send_skb_unicast(bat_priv, newskb, BATADV_UNICAST, 0, + orig_node, vid); + } + rcu_read_unlock(); + return ret; +} + +/** + * batadv_mcast_forw_want_all_rtr6() - forward to nodes with want-all-rtr6 + * @bat_priv: the bat priv with all the soft interface information + * @skb: The multicast packet to transmit + * @vid: the vlan identifier + * + * Sends copies of a frame with multicast destination to any node with a + * BATADV_MCAST_WANT_NO_RTR6 flag unset. A transmission is performed via a + * batman-adv unicast packet for each such destination node. + * + * Return: NET_XMIT_DROP on memory allocation failure, NET_XMIT_SUCCESS + * otherwise. + */ +static int +batadv_mcast_forw_want_all_rtr6(struct batadv_priv *bat_priv, + struct sk_buff *skb, unsigned short vid) +{ + struct batadv_orig_node *orig_node; + int ret = NET_XMIT_SUCCESS; + struct sk_buff *newskb; + + rcu_read_lock(); + hlist_for_each_entry_rcu(orig_node, + &bat_priv->mcast.want_all_rtr6_list, + mcast_want_all_rtr6_node) { + newskb = skb_copy(skb, GFP_ATOMIC); + if (!newskb) { + ret = NET_XMIT_DROP; + break; + } + + batadv_send_skb_unicast(bat_priv, newskb, BATADV_UNICAST, 0, + orig_node, vid); + } + rcu_read_unlock(); + return ret; +} + +/** + * batadv_mcast_forw_want_rtr() - forward packet to nodes in a want-all-rtr list + * @bat_priv: the bat priv with all the soft interface information + * @skb: the multicast packet to transmit + * @vid: the vlan identifier + * + * Sends copies of a frame with multicast destination to any node with a + * BATADV_MCAST_WANT_NO_RTR4 or BATADV_MCAST_WANT_NO_RTR6 flag unset. A + * transmission is performed via a batman-adv unicast packet for each such + * destination node. + * + * Return: NET_XMIT_DROP on memory allocation failure or if the protocol family + * is neither IPv4 nor IPv6. NET_XMIT_SUCCESS otherwise. + */ +static int +batadv_mcast_forw_want_rtr(struct batadv_priv *bat_priv, + struct sk_buff *skb, unsigned short vid) +{ + switch (ntohs(eth_hdr(skb)->h_proto)) { + case ETH_P_IP: + return batadv_mcast_forw_want_all_rtr4(bat_priv, skb, vid); + case ETH_P_IPV6: + return batadv_mcast_forw_want_all_rtr6(bat_priv, skb, vid); + default: + /* we shouldn't be here... */ + return NET_XMIT_DROP; + } +} + +/** * batadv_mcast_forw_send() - send packet to any detected multicast recpient * @bat_priv: the bat priv with all the soft interface information * @skb: the multicast packet to transmit @@ -1508,6 +1725,12 @@ int batadv_mcast_forw_send(struct batadv_priv *bat_priv, struct sk_buff *skb, return ret; }
+ ret = batadv_mcast_forw_want_rtr(bat_priv, skb, vid); + if (ret != NET_XMIT_SUCCESS) { + kfree_skb(skb); + return ret; + } + consume_skb(skb); return ret; }