1 files changed, 709 insertions, 0 deletions

diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c
new file mode 100644
index 00000000..6f9b9b78
--- /dev/null
+++ b/net/batman-adv/gateway_client.c
@@ -0,0 +1,709 @@
+/*
+ * Copyright (C) 2009-2012 B.A.T.M.A.N. contributors:
+ *
+ * Marek Lindner
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA
+ *
+ */
+
+#include "main.h"
+#include "bat_sysfs.h"
+#include "gateway_client.h"
+#include "gateway_common.h"
+#include "hard-interface.h"
+#include "originator.h"
+#include "translation-table.h"
+#include "routing.h"
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/udp.h>
+#include <linux/if_vlan.h>
+
+/* This is the offset of the options field in a dhcp packet starting at
+ * the beginning of the dhcp header */
+#define DHCP_OPTIONS_OFFSET 240
+#define DHCP_REQUEST 3
+
+static void gw_node_free_ref(struct gw_node *gw_node)
+{
+	if (atomic_dec_and_test(&gw_node->refcount))
+		kfree_rcu(gw_node, rcu);
+}
+
+static struct gw_node *gw_get_selected_gw_node(struct bat_priv *bat_priv)
+{
+	struct gw_node *gw_node;
+
+	rcu_read_lock();
+	gw_node = rcu_dereference(bat_priv->curr_gw);
+	if (!gw_node)
+		goto out;
+
+	if (!atomic_inc_not_zero(&gw_node->refcount))
+		gw_node = NULL;
+
+out:
+	rcu_read_unlock();
+	return gw_node;
+}
+
+struct orig_node *gw_get_selected_orig(struct bat_priv *bat_priv)
+{
+	struct gw_node *gw_node;
+	struct orig_node *orig_node = NULL;
+
+	gw_node = gw_get_selected_gw_node(bat_priv);
+	if (!gw_node)
+		goto out;
+
+	rcu_read_lock();
+	orig_node = gw_node->orig_node;
+	if (!orig_node)
+		goto unlock;
+
+	if (!atomic_inc_not_zero(&orig_node->refcount))
+		orig_node = NULL;
+
+unlock:
+	rcu_read_unlock();
+out:
+	if (gw_node)
+		gw_node_free_ref(gw_node);
+	return orig_node;
+}
+
+static void gw_select(struct bat_priv *bat_priv, struct gw_node *new_gw_node)
+{
+	struct gw_node *curr_gw_node;
+
+	spin_lock_bh(&bat_priv->gw_list_lock);
+
+	if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount))
+		new_gw_node = NULL;
+
+	curr_gw_node = rcu_dereference_protected(bat_priv->curr_gw, 1);
+	rcu_assign_pointer(bat_priv->curr_gw, new_gw_node);
+
+	if (curr_gw_node)
+		gw_node_free_ref(curr_gw_node);
+
+	spin_unlock_bh(&bat_priv->gw_list_lock);
+}
+
+void gw_deselect(struct bat_priv *bat_priv)
+{
+	atomic_set(&bat_priv->gw_reselect, 1);
+}
+
+static struct gw_node *gw_get_best_gw_node(struct bat_priv *bat_priv)
+{
+	struct neigh_node *router;
+	struct hlist_node *node;
+	struct gw_node *gw_node, *curr_gw = NULL;
+	uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
+	uint8_t max_tq = 0;
+	int down, up;
+
+	rcu_read_lock();
+	hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
+		if (gw_node->deleted)
+			continue;
+
+		router = orig_node_get_router(gw_node->orig_node);
+		if (!router)
+			continue;
+
+		if (!atomic_inc_not_zero(&gw_node->refcount))
+			goto next;
+
+		switch (atomic_read(&bat_priv->gw_sel_class)) {
+		case 1: /* fast connection */
+			gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags,
+					     &down, &up);
+
+			tmp_gw_factor = (router->tq_avg * router->tq_avg *
+					 down * 100 * 100) /
+					 (TQ_LOCAL_WINDOW_SIZE *
+					 TQ_LOCAL_WINDOW_SIZE * 64);
+
+			if ((tmp_gw_factor > max_gw_factor) ||
+			    ((tmp_gw_factor == max_gw_factor) &&
+			     (router->tq_avg > max_tq))) {
+				if (curr_gw)
+					gw_node_free_ref(curr_gw);
+				curr_gw = gw_node;
+				atomic_inc(&curr_gw->refcount);
+			}
+			break;
+
+		default: /**
+			  * 2:  stable connection (use best statistic)
+			  * 3:  fast-switch (use best statistic but change as
+			  *     soon as a better gateway appears)
+			  * XX: late-switch (use best statistic but change as
+			  *     soon as a better gateway appears which has
+			  *     $routing_class more tq points)
+			  **/
+			if (router->tq_avg > max_tq) {
+				if (curr_gw)
+					gw_node_free_ref(curr_gw);
+				curr_gw = gw_node;
+				atomic_inc(&curr_gw->refcount);
+			}
+			break;
+		}
+
+		if (router->tq_avg > max_tq)
+			max_tq = router->tq_avg;
+
+		if (tmp_gw_factor > max_gw_factor)
+			max_gw_factor = tmp_gw_factor;
+
+		gw_node_free_ref(gw_node);
+
+next:
+		neigh_node_free_ref(router);
+	}
+	rcu_read_unlock();
+
+	return curr_gw;
+}
+
+void gw_election(struct bat_priv *bat_priv)
+{
+	struct gw_node *curr_gw = NULL, *next_gw = NULL;
+	struct neigh_node *router = NULL;
+	char gw_addr[18] = { '\0' };
+
+	/**
+	 * The batman daemon checks here if we already passed a full originator
+	 * cycle in order to make sure we don't choose the first gateway we
+	 * hear about. This check is based on the daemon's uptime which we
+	 * don't have.
+	 **/
+	if (atomic_read(&bat_priv->gw_mode) != GW_MODE_CLIENT)
+		goto out;
+
+	if (!atomic_dec_not_zero(&bat_priv->gw_reselect))
+		goto out;
+
+	curr_gw = gw_get_selected_gw_node(bat_priv);
+
+	next_gw = gw_get_best_gw_node(bat_priv);
+
+	if (curr_gw == next_gw)
+		goto out;
+
+	if (next_gw) {
+		sprintf(gw_addr, "%pM", next_gw->orig_node->orig);
+
+		router = orig_node_get_router(next_gw->orig_node);
+		if (!router) {
+			gw_deselect(bat_priv);
+			goto out;
+		}
+	}
+
+	if ((curr_gw) && (!next_gw)) {
+		bat_dbg(DBG_BATMAN, bat_priv,
+			"Removing selected gateway - no gateway in range\n");
+		throw_uevent(bat_priv, UEV_GW, UEV_DEL, NULL);
+	} else if ((!curr_gw) && (next_gw)) {
+		bat_dbg(DBG_BATMAN, bat_priv,
+			"Adding route to gateway %pM (gw_flags: %i, tq: %i)\n",
+			next_gw->orig_node->orig, next_gw->orig_node->gw_flags,
+			router->tq_avg);
+		throw_uevent(bat_priv, UEV_GW, UEV_ADD, gw_addr);
+	} else {
+		bat_dbg(DBG_BATMAN, bat_priv,
+			"Changing route to gateway %pM (gw_flags: %i, tq: %i)\n",
+			next_gw->orig_node->orig, next_gw->orig_node->gw_flags,
+			router->tq_avg);
+		throw_uevent(bat_priv, UEV_GW, UEV_CHANGE, gw_addr);
+	}
+
+	gw_select(bat_priv, next_gw);
+
+out:
+	if (curr_gw)
+		gw_node_free_ref(curr_gw);
+	if (next_gw)
+		gw_node_free_ref(next_gw);
+	if (router)
+		neigh_node_free_ref(router);
+}
+
+void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node)
+{
+	struct orig_node *curr_gw_orig;
+	struct neigh_node *router_gw = NULL, *router_orig = NULL;
+	uint8_t gw_tq_avg, orig_tq_avg;
+
+	curr_gw_orig = gw_get_selected_orig(bat_priv);
+	if (!curr_gw_orig)
+		goto deselect;
+
+	router_gw = orig_node_get_router(curr_gw_orig);
+	if (!router_gw)
+		goto deselect;
+
+	/* this node already is the gateway */
+	if (curr_gw_orig == orig_node)
+		goto out;
+
+	router_orig = orig_node_get_router(orig_node);
+	if (!router_orig)
+		goto out;
+
+	gw_tq_avg = router_gw->tq_avg;
+	orig_tq_avg = router_orig->tq_avg;
+
+	/* the TQ value has to be better */
+	if (orig_tq_avg < gw_tq_avg)
+		goto out;
+
+	/**
+	 * if the routing class is greater than 3 the value tells us how much
+	 * greater the TQ value of the new gateway must be
+	 **/
+	if ((atomic_read(&bat_priv->gw_sel_class) > 3) &&
+	    (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class)))
+		goto out;
+
+	bat_dbg(DBG_BATMAN, bat_priv,
+		"Restarting gateway selection: better gateway found (tq curr: %i, tq new: %i)\n",
+		gw_tq_avg, orig_tq_avg);
+
+deselect:
+	gw_deselect(bat_priv);
+out:
+	if (curr_gw_orig)
+		orig_node_free_ref(curr_gw_orig);
+	if (router_gw)
+		neigh_node_free_ref(router_gw);
+	if (router_orig)
+		neigh_node_free_ref(router_orig);
+
+	return;
+}
+
+static void gw_node_add(struct bat_priv *bat_priv,
+			struct orig_node *orig_node, uint8_t new_gwflags)
+{
+	struct gw_node *gw_node;
+	int down, up;
+
+	gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC);
+	if (!gw_node)
+		return;
+
+	INIT_HLIST_NODE(&gw_node->list);
+	gw_node->orig_node = orig_node;
+	atomic_set(&gw_node->refcount, 1);
+
+	spin_lock_bh(&bat_priv->gw_list_lock);
+	hlist_add_head_rcu(&gw_node->list, &bat_priv->gw_list);
+	spin_unlock_bh(&bat_priv->gw_list_lock);
+
+	gw_bandwidth_to_kbit(new_gwflags, &down, &up);
+	bat_dbg(DBG_BATMAN, bat_priv,
+		"Found new gateway %pM -> gw_class: %i - %i%s/%i%s\n",
+		orig_node->orig, new_gwflags,
+		(down > 2048 ? down / 1024 : down),
+		(down > 2048 ? "MBit" : "KBit"),
+		(up > 2048 ? up / 1024 : up),
+		(up > 2048 ? "MBit" : "KBit"));
+}
+
+void gw_node_update(struct bat_priv *bat_priv,
+		    struct orig_node *orig_node, uint8_t new_gwflags)
+{
+	struct hlist_node *node;
+	struct gw_node *gw_node, *curr_gw;
+
+	/**
+	 * Note: We don't need a NULL check here, since curr_gw never gets
+	 * dereferenced. If curr_gw is NULL we also should not exit as we may
+	 * have this gateway in our list (duplication check!) even though we
+	 * have no currently selected gateway.
+	 */
+	curr_gw = gw_get_selected_gw_node(bat_priv);
+
+	rcu_read_lock();
+	hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
+		if (gw_node->orig_node != orig_node)
+			continue;
+
+		bat_dbg(DBG_BATMAN, bat_priv,
+			"Gateway class of originator %pM changed from %i to %i\n",
+			orig_node->orig, gw_node->orig_node->gw_flags,
+			new_gwflags);
+
+		gw_node->deleted = 0;
+
+		if (new_gwflags == NO_FLAGS) {
+			gw_node->deleted = jiffies;
+			bat_dbg(DBG_BATMAN, bat_priv,
+				"Gateway %pM removed from gateway list\n",
+				orig_node->orig);
+
+			if (gw_node == curr_gw)
+				goto deselect;
+		}
+
+		goto unlock;
+	}
+
+	if (new_gwflags == NO_FLAGS)
+		goto unlock;
+
+	gw_node_add(bat_priv, orig_node, new_gwflags);
+	goto unlock;
+
+deselect:
+	gw_deselect(bat_priv);
+unlock:
+	rcu_read_unlock();
+
+	if (curr_gw)
+		gw_node_free_ref(curr_gw);
+}
+
+void gw_node_delete(struct bat_priv *bat_priv, struct orig_node *orig_node)
+{
+	gw_node_update(bat_priv, orig_node, 0);
+}
+
+void gw_node_purge(struct bat_priv *bat_priv)
+{
+	struct gw_node *gw_node, *curr_gw;
+	struct hlist_node *node, *node_tmp;
+	unsigned long timeout = msecs_to_jiffies(2 * PURGE_TIMEOUT);
+	int do_deselect = 0;
+
+	curr_gw = gw_get_selected_gw_node(bat_priv);
+
+	spin_lock_bh(&bat_priv->gw_list_lock);
+
+	hlist_for_each_entry_safe(gw_node, node, node_tmp,
+				  &bat_priv->gw_list, list) {
+		if (((!gw_node->deleted) ||
+		     (time_before(jiffies, gw_node->deleted + timeout))) &&
+		    atomic_read(&bat_priv->mesh_state) == MESH_ACTIVE)
+			continue;
+
+		if (curr_gw == gw_node)
+			do_deselect = 1;
+
+		hlist_del_rcu(&gw_node->list);
+		gw_node_free_ref(gw_node);
+	}
+
+	spin_unlock_bh(&bat_priv->gw_list_lock);
+
+	/* gw_deselect() needs to acquire the gw_list_lock */
+	if (do_deselect)
+		gw_deselect(bat_priv);
+
+	if (curr_gw)
+		gw_node_free_ref(curr_gw);
+}
+
+/**
+ * fails if orig_node has no router
+ */
+static int _write_buffer_text(struct bat_priv *bat_priv, struct seq_file *seq,
+			      const struct gw_node *gw_node)
+{
+	struct gw_node *curr_gw;
+	struct neigh_node *router;
+	int down, up, ret = -1;
+
+	gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags, &down, &up);
+
+	router = orig_node_get_router(gw_node->orig_node);
+	if (!router)
+		goto out;
+
+	curr_gw = gw_get_selected_gw_node(bat_priv);
+
+	ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n",
+			 (curr_gw == gw_node ? "=>" : "  "),
+			 gw_node->orig_node->orig,
+			 router->tq_avg, router->addr,
+			 router->if_incoming->net_dev->name,
+			 gw_node->orig_node->gw_flags,
+			 (down > 2048 ? down / 1024 : down),
+			 (down > 2048 ? "MBit" : "KBit"),
+			 (up > 2048 ? up / 1024 : up),
+			 (up > 2048 ? "MBit" : "KBit"));
+
+	neigh_node_free_ref(router);
+	if (curr_gw)
+		gw_node_free_ref(curr_gw);
+out:
+	return ret;
+}
+
+int gw_client_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 hard_iface *primary_if;
+	struct gw_node *gw_node;
+	struct hlist_node *node;
+	int gw_count = 0, ret = 0;
+
+	primary_if = primary_if_get_selected(bat_priv);
+	if (!primary_if) {
+		ret = seq_printf(seq,
+				 "BATMAN mesh %s disabled - please specify interfaces to enable it\n",
+				 net_dev->name);
+		goto out;
+	}
+
+	if (primary_if->if_status != IF_ACTIVE) {
+		ret = seq_printf(seq,
+				 "BATMAN mesh %s disabled - primary interface not active\n",
+				 net_dev->name);
+		goto out;
+	}
+
+	seq_printf(seq,
+		   "      %-12s (%s/%i) %17s [%10s]: gw_class ... [B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n",
+		   "Gateway", "#", TQ_MAX_VALUE, "Nexthop", "outgoingIF",
+		   SOURCE_VERSION, primary_if->net_dev->name,
+		   primary_if->net_dev->dev_addr, net_dev->name);
+
+	rcu_read_lock();
+	hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
+		if (gw_node->deleted)
+			continue;
+
+		/* fails if orig_node has no router */
+		if (_write_buffer_text(bat_priv, seq, gw_node) < 0)
+			continue;
+
+		gw_count++;
+	}
+	rcu_read_unlock();
+
+	if (gw_count == 0)
+		seq_printf(seq, "No gateways in range ...\n");
+
+out:
+	if (primary_if)
+		hardif_free_ref(primary_if);
+	return ret;
+}
+
+static bool is_type_dhcprequest(struct sk_buff *skb, int header_len)
+{
+	int ret = false;
+	unsigned char *p;
+	int pkt_len;
+
+	if (skb_linearize(skb) < 0)
+		goto out;
+
+	pkt_len = skb_headlen(skb);
+
+	if (pkt_len < header_len + DHCP_OPTIONS_OFFSET + 1)
+		goto out;
+
+	p = skb->data + header_len + DHCP_OPTIONS_OFFSET;
+	pkt_len -= header_len + DHCP_OPTIONS_OFFSET + 1;
+
+	/* Access the dhcp option lists. Each entry is made up by:
+	 * - octet 1: option type
+	 * - octet 2: option data len (only if type != 255 and 0)
+	 * - octet 3: option data */
+	while (*p != 255 && !ret) {
+		/* p now points to the first octet: option type */
+		if (*p == 53) {
+			/* type 53 is the message type option.
+			 * Jump the len octet and go to the data octet */
+			if (pkt_len < 2)
+				goto out;
+			p += 2;
+
+			/* check if the message type is what we need */
+			if (*p == DHCP_REQUEST)
+				ret = true;
+			break;
+		} else if (*p == 0) {
+			/* option type 0 (padding), just go forward */
+			if (pkt_len < 1)
+				goto out;
+			pkt_len--;
+			p++;
+		} else {
+			/* This is any other option. So we get the length... */
+			if (pkt_len < 1)
+				goto out;
+			pkt_len--;
+			p++;
+
+			/* ...and then we jump over the data */
+			if (pkt_len < *p)
+				goto out;
+			pkt_len -= *p;
+			p += (*p);
+		}
+	}
+out:
+	return ret;
+}
+
+bool gw_is_dhcp_target(struct sk_buff *skb, unsigned int *header_len)
+{
+	struct ethhdr *ethhdr;
+	struct iphdr *iphdr;
+	struct ipv6hdr *ipv6hdr;
+	struct udphdr *udphdr;
+
+	/* check for ethernet header */
+	if (!pskb_may_pull(skb, *header_len + ETH_HLEN))
+		return false;
+	ethhdr = (struct ethhdr *)skb->data;
+	*header_len += ETH_HLEN;
+
+	/* check for initial vlan header */
+	if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
+		if (!pskb_may_pull(skb, *header_len + VLAN_HLEN))
+			return false;
+		ethhdr = (struct ethhdr *)(skb->data + VLAN_HLEN);
+		*header_len += VLAN_HLEN;
+	}
+
+	/* check for ip header */
+	switch (ntohs(ethhdr->h_proto)) {
+	case ETH_P_IP:
+		if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr)))
+			return false;
+		iphdr = (struct iphdr *)(skb->data + *header_len);
+		*header_len += iphdr->ihl * 4;
+
+		/* check for udp header */
+		if (iphdr->protocol != IPPROTO_UDP)
+			return false;
+
+		break;
+	case ETH_P_IPV6:
+		if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr)))
+			return false;
+		ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len);
+		*header_len += sizeof(*ipv6hdr);
+
+		/* check for udp header */
+		if (ipv6hdr->nexthdr != IPPROTO_UDP)
+			return false;
+
+		break;
+	default:
+		return false;
+	}
+
+	if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr)))
+		return false;
+	udphdr = (struct udphdr *)(skb->data + *header_len);
+	*header_len += sizeof(*udphdr);
+
+	/* check for bootp port */
+	if ((ntohs(ethhdr->h_proto) == ETH_P_IP) &&
+	    (ntohs(udphdr->dest) != 67))
+		return false;
+
+	if ((ntohs(ethhdr->h_proto) == ETH_P_IPV6) &&
+	    (ntohs(udphdr->dest) != 547))
+		return false;
+
+	return true;
+}
+
+bool gw_out_of_range(struct bat_priv *bat_priv,
+		     struct sk_buff *skb, struct ethhdr *ethhdr)
+{
+	struct neigh_node *neigh_curr = NULL, *neigh_old = NULL;
+	struct orig_node *orig_dst_node = NULL;
+	struct gw_node *curr_gw = NULL;
+	bool ret, out_of_range = false;
+	unsigned int header_len = 0;
+	uint8_t curr_tq_avg;
+
+	ret = gw_is_dhcp_target(skb, &header_len);
+	if (!ret)
+		goto out;
+
+	orig_dst_node = transtable_search(bat_priv, ethhdr->h_source,
+					  ethhdr->h_dest);
+	if (!orig_dst_node)
+		goto out;
+
+	if (!orig_dst_node->gw_flags)
+		goto out;
+
+	ret = is_type_dhcprequest(skb, header_len);
+	if (!ret)
+		goto out;
+
+	switch (atomic_read(&bat_priv->gw_mode)) {
+	case GW_MODE_SERVER:
+		/* If we are a GW then we are our best GW. We can artificially
+		 * set the tq towards ourself as the maximum value */
+		curr_tq_avg = TQ_MAX_VALUE;
+		break;
+	case GW_MODE_CLIENT:
+		curr_gw = gw_get_selected_gw_node(bat_priv);
+		if (!curr_gw)
+			goto out;
+
+		/* packet is going to our gateway */
+		if (curr_gw->orig_node == orig_dst_node)
+			goto out;
+
+		/* If the dhcp packet has been sent to a different gw,
+		 * we have to evaluate whether the old gw is still
+		 * reliable enough */
+		neigh_curr = find_router(bat_priv, curr_gw->orig_node, NULL);
+		if (!neigh_curr)
+			goto out;
+
+		curr_tq_avg = neigh_curr->tq_avg;
+		break;
+	case GW_MODE_OFF:
+	default:
+		goto out;
+	}
+
+	neigh_old = find_router(bat_priv, orig_dst_node, NULL);
+	if (!neigh_old)
+		goto out;
+
+	if (curr_tq_avg - neigh_old->tq_avg > GW_THRESHOLD)
+		out_of_range = true;
+
+out:
+	if (orig_dst_node)
+		orig_node_free_ref(orig_dst_node);
+	if (curr_gw)
+		gw_node_free_ref(curr_gw);
+	if (neigh_old)
+		neigh_node_free_ref(neigh_old);
+	if (neigh_curr)
+		neigh_node_free_ref(neigh_curr);
+	return out_of_range;
+}