[B.A.T.M.A.N.] LAN loop avoidance (part II)

[B.A.T.M.A.N.] LAN loop avoidance (part II)

[Marek Lindner]

Hi,

since nobody objected to the concept regarding lan loops that I presented a 
couple of days ago, I went forward and improved the code:
* locking has been revised
* batctl support was added

The new patches require the latest trunk.

Regards,
Marek

[B.A.T.M.A.N.] [PATCH 1/2] batman-adv: softif lan loop avoidance

[Marek Lindner]

By connecting multiple batman-adv mesh nodes to the same LAN network
an ethernet loop can be created when the soft-interface is bridged
with the LAN interface. A simple visualization of the loop:

node1  <-- LAN  -->  node2
   |                   |
 wifi  <-- mesh -->  wifi

This patch adds the functionality to detect other batman-adv nodes
connected to the LAN and select a 'gateway' to talk to the
non-batman-adv devices on this LAN. All traffic from and to the mesh
will be handled by this gateway to avoid the loop. OGMs received via
the soft-interface are interpreted as 'port announcements' to locate
potential batman-adv nodes. The patch can also deal with vlans on
top of batX and offers a list of LAN neighbors via debugfs.

Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
---
 batman-adv/bat_debugfs.c    |    9 ++
 batman-adv/main.c           |    2 +
 batman-adv/main.h           |    2 +
 batman-adv/originator.c     |    3 +
 batman-adv/routing.c        |   12 +-
 batman-adv/routing.h        |    2 +
 batman-adv/soft-interface.c |  302 +++++++++++++++++++++++++++++++++++++++++--
 batman-adv/soft-interface.h |    5 +-
 batman-adv/types.h          |   12 ++
 9 files changed, 332 insertions(+), 17 deletions(-)

diff --git a/batman-adv/bat_debugfs.c b/batman-adv/bat_debugfs.c
index bd4a12e..3fcb102 100644
--- a/batman-adv/bat_debugfs.c
+++ b/batman-adv/bat_debugfs.c
@@ -29,6 +29,7 @@
 #include "hard-interface.h"
 #include "gateway_common.h"
 #include "gateway_client.h"
+#include "soft-interface.h"
 #include "vis.h"
 #include "icmp_socket.h"
 #include "compat.h"
@@ -236,6 +237,12 @@ static int gateways_open(struct inode *inode, struct file *file)
 	return single_open(file, gw_client_seq_print_text, net_dev);
 }
 
+static int softif_neigh_open(struct inode *inode, struct file *file)
+{
+	struct net_device *net_dev = (struct net_device *)inode->i_private;
+	return single_open(file, softif_neigh_seq_print_text, net_dev);
+}
+
 static int transtable_global_open(struct inode *inode, struct file *file)
 {
 	struct net_device *net_dev = (struct net_device *)inode->i_private;
@@ -273,6 +280,7 @@ struct bat_debuginfo bat_debuginfo_##_name = {	\
 
 static BAT_DEBUGINFO(originators, S_IRUGO, originators_open);
 static BAT_DEBUGINFO(gateways, S_IRUGO, gateways_open);
+static BAT_DEBUGINFO(softif_neigh, S_IRUGO, softif_neigh_open);
 static BAT_DEBUGINFO(transtable_global, S_IRUGO, transtable_global_open);
 static BAT_DEBUGINFO(transtable_local, S_IRUGO, transtable_local_open);
 static BAT_DEBUGINFO(vis_data, S_IRUGO, vis_data_open);
@@ -280,6 +288,7 @@ static BAT_DEBUGINFO(vis_data, S_IRUGO, vis_data_open);
 static struct bat_debuginfo *mesh_debuginfos[] = {
 	&bat_debuginfo_originators,
 	&bat_debuginfo_gateways,
+	&bat_debuginfo_softif_neigh,
 	&bat_debuginfo_transtable_global,
 	&bat_debuginfo_transtable_local,
 	&bat_debuginfo_vis_data,
diff --git a/batman-adv/main.c b/batman-adv/main.c
index a067f75..0afa508 100644
--- a/batman-adv/main.c
+++ b/batman-adv/main.c
@@ -89,10 +89,12 @@ int mesh_init(struct net_device *soft_iface)
 	spin_lock_init(&bat_priv->gw_list_lock);
 	spin_lock_init(&bat_priv->vis_hash_lock);
 	spin_lock_init(&bat_priv->vis_list_lock);
+	spin_lock_init(&bat_priv->softif_neigh_lock);
 
 	INIT_HLIST_HEAD(&bat_priv->forw_bat_list);
 	INIT_HLIST_HEAD(&bat_priv->forw_bcast_list);
 	INIT_HLIST_HEAD(&bat_priv->gw_list);
+	INIT_HLIST_HEAD(&bat_priv->softif_neigh_list);
 
 	if (originator_init(bat_priv) < 1)
 		goto err;
diff --git a/batman-adv/main.h b/batman-adv/main.h
index 1528f7a..cc42eb4 100644
--- a/batman-adv/main.h
+++ b/batman-adv/main.h
@@ -72,6 +72,8 @@
 				   * forw_packet->direct_link_flags */
 #define MAX_AGGREGATION_MS 100
 
+#define SOFTIF_NEIGH_TIMEOUT 180000 /* 3 minutes */
+
 #define RESET_PROTECTION_MS 30000
 #define EXPECTED_SEQNO_RANGE	65536
 /* don't reset again within 30 seconds */
diff --git a/batman-adv/originator.c b/batman-adv/originator.c
index 3424ac2..a7b74f0 100644
--- a/batman-adv/originator.c
+++ b/batman-adv/originator.c
@@ -30,6 +30,7 @@
 #include "gateway_client.h"
 #include "hard-interface.h"
 #include "unicast.h"
+#include "soft-interface.h"
 
 static void purge_orig(struct work_struct *work);
 
@@ -292,6 +293,8 @@ static void _purge_orig(struct bat_priv *bat_priv)
 
 	gw_node_purge_deleted(bat_priv);
 	gw_election(bat_priv);
+
+	softif_neigh_purge(bat_priv);
 }
 
 static void purge_orig(struct work_struct *work)
diff --git a/batman-adv/routing.c b/batman-adv/routing.c
index 37ad3c4..1377f01 100644
--- a/batman-adv/routing.c
+++ b/batman-adv/routing.c
@@ -1133,8 +1133,8 @@ static int check_unicast_packet(struct sk_buff *skb, int hdr_size)
 	return 0;
 }
 
-static int route_unicast_packet(struct sk_buff *skb,
-				struct batman_if *recv_if, int hdr_size)
+int route_unicast_packet(struct sk_buff *skb, struct batman_if *recv_if,
+			 int hdr_size)
 {
 	struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 	struct orig_node *orig_node;
@@ -1202,7 +1202,7 @@ static int route_unicast_packet(struct sk_buff *skb,
 			return NET_RX_SUCCESS;
 
 		skb = new_skb;
-		unicast_packet = (struct unicast_packet *) skb->data;
+		unicast_packet = (struct unicast_packet *)skb->data;
 	}
 
 	/* decrement ttl */
@@ -1226,7 +1226,7 @@ int recv_unicast_packet(struct sk_buff *skb, struct batman_if *recv_if)
 
 	/* packet for me */
 	if (is_my_mac(unicast_packet->dest)) {
-		interface_rx(recv_if->soft_iface, skb, hdr_size);
+		interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size);
 		return NET_RX_SUCCESS;
 	}
 
@@ -1258,7 +1258,7 @@ int recv_ucast_frag_packet(struct sk_buff *skb, struct batman_if *recv_if)
 		if (!new_skb)
 			return NET_RX_SUCCESS;
 
-		interface_rx(recv_if->soft_iface, new_skb,
+		interface_rx(recv_if->soft_iface, new_skb, recv_if,
 			     sizeof(struct unicast_packet));
 		return NET_RX_SUCCESS;
 	}
@@ -1340,7 +1340,7 @@ int recv_bcast_packet(struct sk_buff *skb, struct batman_if *recv_if)
 	add_bcast_packet_to_list(bat_priv, skb);
 
 	/* broadcast for me */
-	interface_rx(recv_if->soft_iface, skb, hdr_size);
+	interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size);
 
 	return NET_RX_SUCCESS;
 }
diff --git a/batman-adv/routing.h b/batman-adv/routing.h
index 06ea99d..8f7db1c 100644
--- a/batman-adv/routing.h
+++ b/batman-adv/routing.h
@@ -32,6 +32,8 @@ void receive_bat_packet(struct ethhdr *ethhdr,
 void update_routes(struct bat_priv *bat_priv, struct orig_node *orig_node,
 		   struct neigh_node *neigh_node, unsigned char *hna_buff,
 		   int hna_buff_len);
+int route_unicast_packet(struct sk_buff *skb, struct batman_if *recv_if,
+			 int hdr_size);
 int recv_icmp_packet(struct sk_buff *skb, struct batman_if *recv_if);
 int recv_unicast_packet(struct sk_buff *skb, struct batman_if *recv_if);
 int recv_ucast_frag_packet(struct sk_buff *skb, struct batman_if *recv_if);
diff --git a/batman-adv/soft-interface.c b/batman-adv/soft-interface.c
index 2a84d3b..779da31 100644
--- a/batman-adv/soft-interface.c
+++ b/batman-adv/soft-interface.c
@@ -35,8 +35,10 @@
 #include <linux/slab.h>
 #include <linux/ethtool.h>
 #include <linux/etherdevice.h>
+#include <linux/if_vlan.h>
 #include "compat.h"
 #include "unicast.h"
+#include "routing.h"
 
 
 static int bat_get_settings(struct net_device *dev, struct ethtool_cmd *cmd);
@@ -78,6 +80,214 @@ int my_skb_head_push(struct sk_buff *skb, unsigned int len)
 	return 0;
 }
 
+static void softif_neigh_hold(struct softif_neigh *softif_neigh)
+{
+	if (!softif_neigh)
+		return;
+
+	atomic_inc(&softif_neigh->refcnt);
+}
+
+static void softif_neigh_put(struct softif_neigh *softif_neigh)
+{
+	if (!softif_neigh)
+		return;
+
+	if (atomic_dec_and_test(&softif_neigh->refcnt))
+		kfree(softif_neigh);
+}
+
+void softif_neigh_purge(struct bat_priv *bat_priv)
+{
+	struct softif_neigh *softif_neigh;
+	struct hlist_node *node, *node_tmp;
+
+	hlist_for_each_entry_safe(softif_neigh, node, node_tmp,
+				  &bat_priv->softif_neigh_list, list) {
+
+		if (!time_after(jiffies, softif_neigh->last_seen +
+				msecs_to_jiffies(SOFTIF_NEIGH_TIMEOUT)))
+			continue;
+
+		spin_lock(&bat_priv->softif_neigh_lock);
+		hlist_del_rcu(&softif_neigh->list);
+		spin_unlock(&bat_priv->softif_neigh_lock);
+
+		if (bat_priv->softif_neigh == softif_neigh) {
+			bat_priv->softif_neigh = NULL;
+			bat_dbg(DBG_ROUTES, bat_priv,
+				 "Current mesh exit point '%pM' vanished "
+				 "(vid: %d).\n",
+				 softif_neigh->addr, softif_neigh->vid);
+			softif_neigh_put(bat_priv->softif_neigh);
+		}
+
+		synchronize_rcu();
+		softif_neigh_put(softif_neigh);
+	}
+}
+
+static struct softif_neigh *softif_neigh_get(struct bat_priv *bat_priv,
+					     uint8_t *addr, short vid)
+{
+	struct softif_neigh *softif_neigh;
+	struct hlist_node *node;
+
+	rcu_read_lock();
+	hlist_for_each_entry_rcu(softif_neigh, node,
+				 &bat_priv->softif_neigh_list, list) {
+		if (memcmp(softif_neigh->addr, addr, ETH_ALEN) != 0)
+			continue;
+
+		if (softif_neigh->vid != vid)
+			continue;
+
+		softif_neigh->last_seen = jiffies;
+		goto found;
+	}
+
+	softif_neigh = kzalloc(sizeof(struct softif_neigh), GFP_ATOMIC);
+	if (!softif_neigh)
+		goto out;
+
+	memcpy(softif_neigh->addr, addr, ETH_ALEN);
+	softif_neigh->vid = vid;
+	softif_neigh->last_seen = jiffies;
+	atomic_set(&softif_neigh->refcnt, 0);
+	softif_neigh_hold(softif_neigh);
+
+	INIT_HLIST_NODE(&softif_neigh->list);
+	spin_lock(&bat_priv->softif_neigh_lock);
+	hlist_add_head_rcu(&softif_neigh->list, &bat_priv->softif_neigh_list);
+	spin_unlock(&bat_priv->softif_neigh_lock);
+
+found:
+	softif_neigh_hold(softif_neigh);
+out:
+	rcu_read_unlock();
+	return softif_neigh;
+}
+
+int softif_neigh_seq_print_text(struct seq_file *seq, void *offset)
+{
+	struct net_device *net_dev = (struct net_device *)seq->private;
+	struct bat_priv *bat_priv = netdev_priv(net_dev);
+	struct softif_neigh *softif_neigh;
+	struct hlist_node *node;
+	size_t buf_size, pos;
+	char *buff;
+
+	if (!bat_priv->primary_if) {
+		return seq_printf(seq, "BATMAN mesh %s disabled - "
+			       "please specify interfaces to enable it\n",
+			       net_dev->name);
+	}
+
+	seq_printf(seq, "Softif neighbor list (%s)\n", net_dev->name);
+
+	buf_size = 1;
+	/* Estimate length for: "   xx:xx:xx:xx:xx:xx\n" */
+	rcu_read_lock();
+	hlist_for_each_entry_rcu(softif_neigh, node,
+				 &bat_priv->softif_neigh_list, list)
+		buf_size += 30;
+	rcu_read_unlock();
+
+	buff = kmalloc(buf_size, GFP_ATOMIC);
+	if (!buff)
+		return -ENOMEM;
+
+	buff[0] = '\0';
+	pos = 0;
+
+	rcu_read_lock();
+	hlist_for_each_entry_rcu(softif_neigh, node,
+				 &bat_priv->softif_neigh_list, list) {
+		pos += snprintf(buff + pos, 31, "%s %pM (vid: %d)\n",
+				bat_priv->softif_neigh == softif_neigh
+				? "=>" : "  ", softif_neigh->addr,
+				softif_neigh->vid);
+	}
+	rcu_read_unlock();
+
+	seq_printf(seq, "%s", buff);
+	kfree(buff);
+	return 0;
+}
+
+void softif_batman_recv(struct sk_buff *skb, struct net_device *dev, short vid)
+{
+	struct bat_priv *bat_priv = netdev_priv(dev);
+	struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
+	struct batman_packet *batman_packet;
+	struct softif_neigh *softif_neigh;
+
+	if (ntohs(ethhdr->h_proto) == ETH_P_8021Q)
+		batman_packet = (struct batman_packet *)
+					(skb->data + ETH_HLEN + VLAN_HLEN);
+	else
+		batman_packet = (struct batman_packet *)(skb->data + ETH_HLEN);
+
+	if (batman_packet->version != COMPAT_VERSION)
+		goto err;
+
+	if (batman_packet->packet_type != BAT_PACKET)
+		goto err;
+
+	if (!(batman_packet->flags & PRIMARIES_FIRST_HOP))
+		goto err;
+
+	if (is_my_mac(batman_packet->orig))
+		goto err;
+
+	softif_neigh = softif_neigh_get(bat_priv, batman_packet->orig, vid);
+
+	if (!softif_neigh)
+		goto err;
+
+	if (bat_priv->softif_neigh == softif_neigh)
+		goto out;
+
+	/* we got a neighbor but its mac is 'bigger' than ours  */
+	if (memcmp(bat_priv->primary_if->net_dev->dev_addr,
+		   softif_neigh->addr, ETH_ALEN) < 0)
+		goto out;
+
+	/* switch to new 'smallest neighbor' */
+	if ((bat_priv->softif_neigh) &&
+	    (memcmp(softif_neigh->addr, bat_priv->softif_neigh->addr,
+							ETH_ALEN) < 0)) {
+		bat_dbg(DBG_ROUTES, bat_priv,
+			"Changing mesh exit point from %pM (vid: %d) "
+			"to %pM (vid: %d).\n",
+			 bat_priv->softif_neigh->addr,
+			 bat_priv->softif_neigh->vid,
+			 softif_neigh->addr, softif_neigh->vid);
+		softif_neigh_put(bat_priv->softif_neigh);
+		bat_priv->softif_neigh = softif_neigh;
+		/* we need to hold the additional reference */
+		goto err;
+	}
+
+	/* close own batX device and use softif_neigh as exit node */
+	if ((!bat_priv->softif_neigh) &&
+	    (memcmp(softif_neigh->addr,
+		    bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN) < 0)) {
+		bat_dbg(DBG_ROUTES, bat_priv,
+			"Setting mesh exit point to %pM (vid: %d).\n",
+			softif_neigh->addr, softif_neigh->vid);
+		bat_priv->softif_neigh = softif_neigh;
+		/* we need to hold the additional reference */
+		goto err;
+	}
+
+out:
+	softif_neigh_put(softif_neigh);
+err:
+	kfree_skb(skb);
+	return;
+}
+
 static int interface_open(struct net_device *dev)
 {
 	netif_start_queue(dev);
@@ -112,7 +322,6 @@ static int interface_set_mac_addr(struct net_device *dev, void *p)
 	}
 
 	memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
-
 	return 0;
 }
 
@@ -132,7 +341,9 @@ int interface_tx(struct sk_buff *skb, struct net_device *soft_iface)
 	struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
 	struct bat_priv *bat_priv = netdev_priv(soft_iface);
 	struct bcast_packet *bcast_packet;
+	struct vlan_ethhdr *vhdr;
 	int data_len = skb->len, ret;
+	short vid = -1;
 	bool bcast_dst = false, do_bcast = true;
 
 	if (atomic_read(&bat_priv->mesh_state) != MESH_ACTIVE)
@@ -140,6 +351,27 @@ int interface_tx(struct sk_buff *skb, struct net_device *soft_iface)
 
 	soft_iface->trans_start = jiffies;
 
+	switch (ntohs(ethhdr->h_proto)) {
+	case ETH_P_8021Q:
+		vhdr = (struct vlan_ethhdr *)skb->data;
+		vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK;
+
+		if (ntohs(vhdr->h_vlan_encapsulated_proto) != ETH_P_BATMAN)
+			break;
+
+		/* fall through */
+	case ETH_P_BATMAN:
+		softif_batman_recv(skb, soft_iface, vid);
+		goto end;
+	}
+
+	/**
+	 * if we have a another chosen mesh exit node in range
+	 * it will transport the packets to the mesh
+	 */
+	if ((bat_priv->softif_neigh) && (bat_priv->softif_neigh->vid == vid))
+		goto dropped;
+
 	/* TODO: check this for locks */
 	hna_local_add(soft_iface, ethhdr->h_source);
 
@@ -199,17 +431,60 @@ end:
 }
 
 void interface_rx(struct net_device *soft_iface,
-		  struct sk_buff *skb, int hdr_size)
+		  struct sk_buff *skb, struct batman_if *recv_if,
+		  int hdr_size)
 {
-	struct bat_priv *priv = netdev_priv(soft_iface);
+	struct bat_priv *bat_priv = netdev_priv(soft_iface);
+	struct unicast_packet *unicast_packet;
+	struct ethhdr *ethhdr;
+	struct vlan_ethhdr *vhdr;
+	short vid = -1;
+	int ret;
 
 	/* check if enough space is available for pulling, and pull */
-	if (!pskb_may_pull(skb, hdr_size)) {
-		kfree_skb(skb);
-		return;
-	}
+	if (!pskb_may_pull(skb, hdr_size))
+		goto dropped;
+
 	skb_pull_rcsum(skb, hdr_size);
-/*	skb_set_mac_header(skb, -sizeof(struct ethhdr));*/
+	skb_reset_mac_header(skb);
+
+	ethhdr = (struct ethhdr *)skb_mac_header(skb);
+
+	switch (ntohs(ethhdr->h_proto)) {
+	case ETH_P_8021Q:
+		vhdr = (struct vlan_ethhdr *)skb->data;
+		vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK;
+
+		if (ntohs(vhdr->h_vlan_encapsulated_proto) != ETH_P_BATMAN)
+			break;
+
+		/* fall through */
+	case ETH_P_BATMAN:
+		goto dropped;
+	}
+
+	/**
+	 * if we have a another chosen mesh exit node in range
+	 * it will transport the packets to the non-mesh network
+	 */
+	if ((bat_priv->softif_neigh) && (bat_priv->softif_neigh->vid == vid)) {
+		skb_push(skb, hdr_size);
+		unicast_packet = (struct unicast_packet *)skb->data;
+
+		if ((unicast_packet->packet_type != BAT_UNICAST) &&
+		    (unicast_packet->packet_type != BAT_UNICAST_FRAG))
+			goto dropped;
+
+		skb_reset_mac_header(skb);
+
+		memcpy(unicast_packet->dest,
+		       bat_priv->softif_neigh->addr, ETH_ALEN);
+		ret = route_unicast_packet(skb, recv_if, hdr_size);
+		if (ret == NET_RX_DROP)
+			goto dropped;
+
+		goto out;
+	}
 
 	/* skb->dev & skb->pkt_type are set here */
 	skb->protocol = eth_type_trans(skb, soft_iface);
@@ -220,12 +495,18 @@ void interface_rx(struct net_device *soft_iface,
 
 /*	skb->ip_summed = CHECKSUM_UNNECESSARY;*/
 
-	priv->stats.rx_packets++;
-	priv->stats.rx_bytes += skb->len + sizeof(struct ethhdr);
+	bat_priv->stats.rx_packets++;
+	bat_priv->stats.rx_bytes += skb->len + sizeof(struct ethhdr);
 
 	soft_iface->last_rx = jiffies;
 
 	netif_rx(skb);
+	return;
+
+dropped:
+	kfree_skb(skb);
+out:
+	return;
 }
 
 #ifdef HAVE_NET_DEVICE_OPS
@@ -316,6 +597,7 @@ struct net_device *softif_create(char *name)
 
 	bat_priv->primary_if = NULL;
 	bat_priv->num_ifaces = 0;
+	bat_priv->softif_neigh = NULL;
 
 	ret = sysfs_add_meshif(soft_iface);
 	if (ret < 0)
diff --git a/batman-adv/soft-interface.h b/batman-adv/soft-interface.h
index 843a7ec..02b7733 100644
--- a/batman-adv/soft-interface.h
+++ b/batman-adv/soft-interface.h
@@ -23,9 +23,12 @@
 #define _NET_BATMAN_ADV_SOFT_INTERFACE_H_
 
 int my_skb_head_push(struct sk_buff *skb, unsigned int len);
+int softif_neigh_seq_print_text(struct seq_file *seq, void *offset);
+void softif_neigh_purge(struct bat_priv *bat_priv);
 int interface_tx(struct sk_buff *skb, struct net_device *soft_iface);
 void interface_rx(struct net_device *soft_iface,
-		  struct sk_buff *skb, int hdr_size);
+		  struct sk_buff *skb, struct batman_if *recv_if,
+		  int hdr_size);
 struct net_device *softif_create(char *name);
 void softif_destroy(struct net_device *soft_iface);
 
diff --git a/batman-adv/types.h b/batman-adv/types.h
index a609100..dfa8784 100644
--- a/batman-adv/types.h
+++ b/batman-adv/types.h
@@ -134,6 +134,8 @@ struct bat_priv {
 	atomic_t bcast_queue_left;
 	atomic_t batman_queue_left;
 	char num_ifaces;
+	struct hlist_head softif_neigh_list;
+	struct softif_neigh *softif_neigh;
 	struct debug_log *debug_log;
 	struct batman_if *primary_if;
 	struct kobject *mesh_obj;
@@ -154,6 +156,7 @@ struct bat_priv {
 	spinlock_t gw_list_lock; /* protects gw_list */
 	spinlock_t vis_hash_lock; /* protects vis_hash */
 	spinlock_t vis_list_lock; /* protects vis_info::recv_list */
+	spinlock_t softif_neigh_lock; /* protects soft-interface neigh list */
 	int16_t num_local_hna;
 	atomic_t hna_local_changed;
 	struct delayed_work hna_work;
@@ -253,4 +256,13 @@ struct recvlist_node {
 	uint8_t mac[ETH_ALEN];
 };
 
+struct softif_neigh {
+	struct hlist_node list;
+	uint8_t addr[ETH_ALEN];
+	unsigned long last_seen;
+	short vid;
+	atomic_t refcnt;
+	struct rcu_head rcu;
+};
+
 #endif /* _NET_BATMAN_ADV_TYPES_H_ */
-- 
1.7.1

Re: [B.A.T.M.A.N.] batman-adv: softif lan loop avoidance

[Lew Pitcher]

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On September 26, 2010 14:57:56 Marek Lindner wrote:
> By connecting multiple batman-adv mesh nodes to the same LAN network
> an ethernet loop can be created when the soft-interface is bridged
> with the LAN interface. A simple visualization of the loop:
>
> node1  <-- LAN  -->  node2
>    |                   |
>  wifi  <-- mesh -->  wifi
>
> This patch adds the functionality to detect other batman-adv nodes
> connected to the LAN and select a 'gateway' to talk to the
> non-batman-adv devices on this LAN. All traffic from and to the mesh
> will be handled by this gateway to avoid the loop. OGMs received via
> the soft-interface are interpreted as 'port announcements' to locate
> potential batman-adv nodes. The patch can also deal with vlans on
> top of batX and offers a list of LAN neighbors via debugfs.

Not meaning to "joggle your elbow" on this, and only for my own information 
and education, I wonder if you could tell me why this approach was selected?

ISTM that, for this sort of loop, 
  node1  <-- LAN  -->  node2
     |                   |
  wifi1  <-- mesh -->  wifi2
you are trying to prevent OGMs from perpetually circulating around. 
Wouldn't "wifi1" be able to recognize it's own OGMs? If so, then why wouldn't 
it just drop them, rather than passing them along to the next node?

If each wifi dropped it's own OGMs, then OGMs would only "circulate" once 
through the loop, and be discarded when they arrive back at their originating 
node.

Obviously, I don't understand enough about batman and batman-adv to be 
critical of the design; I'm simply trying to understand how the design works, 
and why you chose the "gateway" approach to eliminate routing loops.

Thanks
-- 
Lew Pitcher
Master Codewright & JOAT-in-training   | Registered Linux User #112576
Me: http://pitcher.digitalfreehold.ca/ | Just Linux: http://justlinux.ca/
----------      Slackware - Because I know what I'm doing.         ------



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Re: [B.A.T.M.A.N.] batman-adv: softif lan loop avoidance

[Marek Lindner]

On Sunday 26 September 2010 21:16:16 Lew Pitcher wrote:
> you are trying to prevent OGMs from perpetually circulating around. 
> Wouldn't "wifi1" be able to recognize it's own OGMs? If so, then why
> wouldn't  it just drop them, rather than passing them along to the next
> node?
> 
> If each wifi dropped it's own OGMs, then OGMs would only "circulate" once 
> through the loop, and be discarded when they arrive back at their
> originating  node.

Maybe my mail was not clear enough that this problem exists because the 
payload traffic loops, not the batman-adv protocol traffic. As you correctly 
pointed out the OGMs are filtered and dropped if necessary.

By the way, this is not a problem unique to batman-adv. Ethernet loops are a 
common problem in bridged / switched environments. Feel free to search for 
"bridge loop" or "ethernet loop" to find some interesting examples.  

Regards,
Marek

Re: [B.A.T.M.A.N.] batman-adv: softif lan loop avoidance

[DuncanSF]

Sorry for the formatting: my client doesn't understand signed messages.

Lew quoted Marek who wrote:
> This patch adds the functionality to detect other batman-adv nodes
> connected to the LAN and select a 'gateway' to talk to the
> non-batman-adv devices on this LAN.

Doing this defeats part of the purpose of running batman-adv on
a LAN.  Picture the case where nodes have links between each
other both on their wireless interfaces and through Homeplug
adapters like the old Netgear XE102 Ethernet-to-Powerline bridge.

Electing a single mesh-to-LAN gateway as proposed will blackhole
any stations on that LAN unable to reach the elected gateway.

Not everything connected to a LAN port is a standard, reliable
local area network.  *smiles*

duncan.


----- Original Message ----- 
From: "Lew Pitcher" <lew.pitcher@digitalfreehold.ca>
To: "The list for a Better Approach To Mobile Ad-hoc Networking" 
<b.a.t.m.a.n@lists.open-mesh.org>
Sent: Sunday, September 26, 2010 12:16 PM
Subject: Re: [B.A.T.M.A.N.] batman-adv: softif lan loop avoidance

Re: [B.A.T.M.A.N.] batman-adv: softif lan loop avoidance

[Donald Gordon]

On Mon, Sep 27, 2010 at 1:25 PM, DuncanSF
<duncan-tech-openmesh@404.978.org> wrote:
> Doing this defeats part of the purpose of running batman-adv on
> a LAN.  Picture the case where nodes have links between each
> other both on their wireless interfaces and through Homeplug
> adapters like the old Netgear XE102 Ethernet-to-Powerline bridge.
>
> Electing a single mesh-to-LAN gateway as proposed will blackhole
> any stations on that LAN unable to reach the elected gateway.
>
> Not everything connected to a LAN port is a standard, reliable
> local area network.  *smiles*

Surely in that situation you'd run batman-advanced in a topology where
you only sent batman-encapsulated packets over your unreliable
ethernet (which is unreliable in a similar way to adhoc wifi), and
then either configure up your bat0 interfaces locally on every host or
bridge the bat0 interfaces to nice reliable local ethernet networks.
Then batman would automatically choose the best path over the
available networks to connect your islands of reliability :-)

donald

Re: [B.A.T.M.A.N.] batman-adv: softif lan loop avoidance

[Marek Lindner]

On Monday 27 September 2010 02:25:52 DuncanSF wrote:
> Doing this defeats part of the purpose of running batman-adv on
> a LAN.  Picture the case where nodes have links between each
> other both on their wireless interfaces and through Homeplug
> adapters like the old Netgear XE102 Ethernet-to-Powerline bridge

It seems you somewhat misunderstood this new feature. As Donald already 
pointed out: It does not apply in your case.

But thanks a lot for all your questions because it made me aware of  the fact 
that my explanations were not clear enough. To address the matter I wrote a 
document: http://www.open-mesh.org/wiki/bridge-loop-avoidance

Let me know if it answers the questions raised here and also pay close 
attention to the handcrafted fancy graphics. :-)

Regards,
Marek

Re: [B.A.T.M.A.N.] batman-adv: softif lan loop avoidance

[Donald Gordon]

On Tue, Sep 28, 2010 at 4:58 AM, Marek Lindner <lindner_marek@yahoo.de> wrote:
> But thanks a lot for all your questions because it made me aware of  the fact
> that my explanations were not clear enough. To address the matter I wrote a
> document: http://www.open-mesh.org/wiki/bridge-loop-avoidance
>
> Let me know if it answers the questions raised here and also pay close
> attention to the handcrafted fancy graphics. :-)

Questions I still have:

* Does this mean that batman will now send OGMs out the bat0 interface?
* Can the LAN be added as an interface that batman will send "normal"
batman packets out, too?  So bat0 would be in a bridge br0 with e.g.
eth0, but br0 or eth0 would also be set up as an interface batman
would send/recieve batman-encapsulated packets on?

thanks

donald

Re: [B.A.T.M.A.N.] batman-adv: softif lan loop avoidance

[Marek Lindner]

On Monday 27 September 2010 23:00:21 Donald Gordon wrote:
> * Does this mean that batman will now send OGMs out the bat0 interface?

No, OGMs have to originate from the bridge interface bat0 belongs to.


> * Can the LAN be added as an interface that batman will send "normal"
> batman packets out, too?  So bat0 would be in a bridge br0 with e.g.
> eth0, but br0 or eth0 would also be set up as an interface batman
> would send/recieve batman-encapsulated packets on?

If an interface is part of a bridge (e.g. br0) it can't be used by batman-adv 
at the same time. The bridge module pulls in all the traffic. But that always 
has been the case and is not a new development.

Is that a theoretical question or do you have a use case ?


Regards,
Marek

Re: [B.A.T.M.A.N.] [PATCH 1/2] batman-adv: softif lan loop avoidance

[Sven Eckelmann]

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Marek Lindner wrote:
> +static void softif_neigh_hold(struct softif_neigh *softif_neigh)
> +{
> +       if (!softif_neigh)
> +               return;
> +
> +       atomic_inc(&softif_neigh->refcnt);
> +}
> +
> +static void softif_neigh_put(struct softif_neigh *softif_neigh)
> +{
> +       if (!softif_neigh)
> +               return;
> +
> +       if (atomic_dec_and_test(&softif_neigh->refcnt))
> +               kfree(softif_neigh);
> +}

Do you want to change the other _hold and _put functions to make it consistent 
in batman-adv regarding the NULL pointer checks?

> +void softif_neigh_purge(struct bat_priv *bat_priv)
> +{
> +	struct softif_neigh *softif_neigh;
> +	struct hlist_node *node, *node_tmp;
> +
> +	hlist_for_each_entry_safe(softif_neigh, node, node_tmp,
> +				  &bat_priv->softif_neigh_list, list) {
> +
> +		if (!time_after(jiffies, softif_neigh->last_seen +
> +				msecs_to_jiffies(SOFTIF_NEIGH_TIMEOUT)))
> +			continue;
> +
> +		spin_lock(&bat_priv->softif_neigh_lock);
> +		hlist_del_rcu(&softif_neigh->list);
> +		spin_unlock(&bat_priv->softif_neigh_lock);
> +
> +		if (bat_priv->softif_neigh == softif_neigh) {
> +			bat_priv->softif_neigh = NULL;
> +			bat_dbg(DBG_ROUTES, bat_priv,
> +				 "Current mesh exit point '%pM' vanished "
> +				 "(vid: %d).\n",
> +				 softif_neigh->addr, softif_neigh->vid);
> +			softif_neigh_put(bat_priv->softif_neigh);
> +		}
> +
> +		synchronize_rcu();
> +		softif_neigh_put(softif_neigh);
> +	}

You must protect the whole loop and not only the hlist_del_rcu with the 
bat_priv->softif_neigh_lock, And it must be with spin_lock_irqsave because you 
use it in context were irq is disabled and in some with enabled irq 
contexts... or am I wrong?

> +void softif_batman_recv(struct sk_buff *skb, struct net_device *dev, short
> vid) +{
> +	struct bat_priv *bat_priv = netdev_priv(dev);
> +	struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
> +	struct batman_packet *batman_packet;
> +	struct softif_neigh *softif_neigh;
> +
> +	if (ntohs(ethhdr->h_proto) == ETH_P_8021Q)
> +		batman_packet = (struct batman_packet *)
> +					(skb->data + ETH_HLEN + VLAN_HLEN);
> +	else
> +		batman_packet = (struct batman_packet *)(skb->data + ETH_HLEN);
> +
> +	if (batman_packet->version != COMPAT_VERSION)
> +		goto err;
> +
> +	if (batman_packet->packet_type != BAT_PACKET)
> +		goto err;
> +
> +	if (!(batman_packet->flags & PRIMARIES_FIRST_HOP))
> +		goto err;
> +
> +	if (is_my_mac(batman_packet->orig))
> +		goto err;
> +
> +	softif_neigh = softif_neigh_get(bat_priv, batman_packet->orig, vid);
> +
> +	if (!softif_neigh)
> +		goto err;
> +
> +	if (bat_priv->softif_neigh == softif_neigh)
> +		goto out;
> +
> +	/* we got a neighbor but its mac is 'bigger' than ours  */
> +	if (memcmp(bat_priv->primary_if->net_dev->dev_addr,
> +		   softif_neigh->addr, ETH_ALEN) < 0)
> +		goto out;
> +
> +	/* switch to new 'smallest neighbor' */
> +	if ((bat_priv->softif_neigh) &&
> +	    (memcmp(softif_neigh->addr, bat_priv->softif_neigh->addr,
> +							ETH_ALEN) < 0)) {
> +		bat_dbg(DBG_ROUTES, bat_priv,
> +			"Changing mesh exit point from %pM (vid: %d) "
> +			"to %pM (vid: %d).\n",
> +			 bat_priv->softif_neigh->addr,
> +			 bat_priv->softif_neigh->vid,
> +			 softif_neigh->addr, softif_neigh->vid);
> +		softif_neigh_put(bat_priv->softif_neigh);
> +		bat_priv->softif_neigh = softif_neigh;
> +		/* we need to hold the additional reference */
> +		goto err;
> +	}
> +
> +	/* close own batX device and use softif_neigh as exit node */
> +	if ((!bat_priv->softif_neigh) &&
> +	    (memcmp(softif_neigh->addr,
> +		    bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN) < 0)) {
> +		bat_dbg(DBG_ROUTES, bat_priv,
> +			"Setting mesh exit point to %pM (vid: %d).\n",
> +			softif_neigh->addr, softif_neigh->vid);
> +		bat_priv->softif_neigh = softif_neigh;
> +		/* we need to hold the additional reference */
> +		goto err;
> +	}
> +
> +out:
> +	softif_neigh_put(softif_neigh);
> +err:
> +	kfree_skb(skb);
> +	return;
> +}

Can you mark that function as static?

Best regards,
	Sven

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Re: [B.A.T.M.A.N.] [PATCH 1/2] batman-adv: softif lan loop avoidance

[Marek Lindner]

On Tuesday 28 September 2010 23:23:03 Sven Eckelmann wrote:
> Do you want to change the other _hold and _put functions to make it
> consistent in batman-adv regarding the NULL pointer checks?

Yes, I will send patches for that.


> You must protect the whole loop and not only the hlist_del_rcu with the
> bat_priv->softif_neigh_lock, And it must be with spin_lock_irqsave because
> you use it in context were irq is disabled and in some with enabled irq
> contexts... or am I wrong?

No, you are right - I will add the irq locks.


> Can you mark that function as static?

Done.

Thanks for your review,
Marek

[B.A.T.M.A.N.] [PATCH 2/2] batctl: display soft-interface neighbor table

[Marek Lindner]

Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
---
 batctl/debug.c      |    9 +++++++++
 batctl/debug.h      |    2 ++
 batctl/main.c       |    6 ++++++
 batctl/man/batctl.8 |    3 +++
 4 files changed, 20 insertions(+), 0 deletions(-)

diff --git a/batctl/debug.c b/batctl/debug.c
index 1dbc204..ea5e1cb 100644
--- a/batctl/debug.c
+++ b/batctl/debug.c
@@ -61,6 +61,15 @@ void trans_global_usage(void)
 	printf(" \t -w [interval] watch mode - refresh the global translation table continuously\n");
 }
 
+void softif_neigh_usage(void)
+{
+	printf("Usage: batctl [options] softif_neigh \n");
+	printf("options:\n");
+	printf(" \t -h print this help\n");
+	printf(" \t -n don't replace mac addresses with bat-host names\n");
+	printf(" \t -w [interval] watch mode - refresh the soft-interface neighbor table continuously\n");
+}
+
 void gateways_usage(void)
 {
 	printf("Usage: batctl [options] gateways \n");
diff --git a/batctl/debug.h b/batctl/debug.h
index 8bed80e..aa5b362 100644
--- a/batctl/debug.h
+++ b/batctl/debug.h
@@ -24,6 +24,7 @@
 #define DEBUG_ORIGINATORS "originators"
 #define DEBUG_TRANSTABLE_LOCAL "transtable_local"
 #define DEBUG_TRANSTABLE_GLOBAL "transtable_global"
+#define DEBUG_SOFTIF_NEIGH "softif_neigh"
 #define DEBUG_GATEWAYS "gateways"
 #define DEBUG_VIS_DATA "vis_data"
 #define DEBUG_LOG "log"
@@ -31,6 +32,7 @@
 void originators_usage(void);
 void trans_local_usage(void);
 void trans_global_usage(void);
+void softif_neigh_usage(void);
 void gateways_usage(void);
 int handle_debug_table(char *mesh_iface, int argc, char **argv,
 		       char *file_path, void table_usage(void));
diff --git a/batctl/main.c b/batctl/main.c
index 5e3f5d8..9c1195b 100644
--- a/batctl/main.c
+++ b/batctl/main.c
@@ -52,6 +52,7 @@ void print_usage(void) {
 	printf(" \tgateways|gwl                      \tdisplay the gateway server list\n");
 	printf(" \ttranslocal|tl                     \tdisplay the local translation table\n");
 	printf(" \ttransglobal|tg                    \tdisplay the global translation table\n");
+	printf(" \tsoftif_neigh|sn                   \tdisplay the soft-interface neighbor table\n");
 	printf(" \tvis_mode|vm     [mode]            \tdisplay or modify the status of the VIS server\n");
 	printf(" \tvis_data|vd     [dot|JSON]        \tdisplay the VIS data in dot or JSON format\n");
 	printf(" \taggregation|ag  [0|1]             \tdisplay or modify the packet aggregation setting\n");
@@ -136,6 +137,11 @@ int main(int argc, char **argv)
 		ret = handle_debug_table(mesh_iface, argc - 1, argv + 1,
 					 DEBUG_TRANSTABLE_GLOBAL, trans_global_usage);
 
+	} else if ((strcmp(argv[1], "softif_neigh") == 0) || (strcmp(argv[1], "sn") == 0)) {
+
+		ret = handle_debug_table(mesh_iface, argc - 1, argv + 1,
+					 DEBUG_SOFTIF_NEIGH, softif_neigh_usage);
+
 	} else if ((strcmp(argv[1], "loglevel") == 0) || (strcmp(argv[1], "ll") == 0)) {
 
 		ret = handle_loglevel(mesh_iface, argc - 1, argv + 1);
diff --git a/batctl/man/batctl.8 b/batctl/man/batctl.8
index f98e6ad..13822ef 100644
--- a/batctl/man/batctl.8
+++ b/batctl/man/batctl.8
@@ -121,6 +121,9 @@ Display the local translation table. batctl will refresh the list every second i
 .IP "\fBtransglobal\fP|\fBtg\fP   [\fB\-w\fP [\fI\interval\fP]][\fB\-n\fP]"
 Display the global translation table. batctl will refresh the list every second if the "\-w" option was given or add a number to let it refresh at a custom interval in seconds (with optional decimal places). Use "\-n" to let batctl not replace the MAC addresses with bat\-host names in the output.
 .br
+.IP "\fBsoftif_neigh\fP|\fBsn\fP   [\fB\-w\fP [\fI\interval\fP]][\fB\-n\fP]"
+Display the soft\-interface neighbor table. batctl will refresh the list every second if the "\-w" option was given or add a number to let it refresh at a custom interval in seconds (with optional decimal places). Use "\-n" to let batctl not replace the MAC addresses with bat\-host names in the output.
+.br
 .IP "\fBvis_mode|vm\fP	  [\fBmode\fP]\fP"
 If no parameter is given the current vis mode is displayed otherwise the parameter is used to set the vis mode.
 .br
-- 
1.7.1