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-rw-r--r--net/batman-adv/gateway_client.c769
1 files changed, 769 insertions, 0 deletions
diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c
new file mode 100644
index 0000000000..d26124bc27
--- /dev/null
+++ b/net/batman-adv/gateway_client.c
@@ -0,0 +1,769 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) B.A.T.M.A.N. contributors:
+ *
+ * Marek Lindner
+ */
+
+#include "gateway_client.h"
+#include "main.h"
+
+#include <linux/atomic.h>
+#include <linux/byteorder/generic.h>
+#include <linux/container_of.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/in.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/kernel.h>
+#include <linux/kref.h>
+#include <linux/list.h>
+#include <linux/lockdep.h>
+#include <linux/netdevice.h>
+#include <linux/netlink.h>
+#include <linux/rculist.h>
+#include <linux/rcupdate.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/stddef.h>
+#include <linux/udp.h>
+#include <net/sock.h>
+#include <uapi/linux/batadv_packet.h>
+#include <uapi/linux/batman_adv.h>
+
+#include "hard-interface.h"
+#include "log.h"
+#include "netlink.h"
+#include "originator.h"
+#include "routing.h"
+#include "soft-interface.h"
+#include "translation-table.h"
+
+/* These are the offsets of the "hw type" and "hw address length" in the dhcp
+ * packet starting at the beginning of the dhcp header
+ */
+#define BATADV_DHCP_HTYPE_OFFSET 1
+#define BATADV_DHCP_HLEN_OFFSET 2
+/* Value of htype representing Ethernet */
+#define BATADV_DHCP_HTYPE_ETHERNET 0x01
+/* This is the offset of the "chaddr" field in the dhcp packet starting at the
+ * beginning of the dhcp header
+ */
+#define BATADV_DHCP_CHADDR_OFFSET 28
+
+/**
+ * batadv_gw_node_release() - release gw_node from lists and queue for free
+ * after rcu grace period
+ * @ref: kref pointer of the gw_node
+ */
+void batadv_gw_node_release(struct kref *ref)
+{
+ struct batadv_gw_node *gw_node;
+
+ gw_node = container_of(ref, struct batadv_gw_node, refcount);
+
+ batadv_orig_node_put(gw_node->orig_node);
+ kfree_rcu(gw_node, rcu);
+}
+
+/**
+ * batadv_gw_get_selected_gw_node() - Get currently selected gateway
+ * @bat_priv: the bat priv with all the soft interface information
+ *
+ * Return: selected gateway (with increased refcnt), NULL on errors
+ */
+struct batadv_gw_node *
+batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv)
+{
+ struct batadv_gw_node *gw_node;
+
+ rcu_read_lock();
+ gw_node = rcu_dereference(bat_priv->gw.curr_gw);
+ if (!gw_node)
+ goto out;
+
+ if (!kref_get_unless_zero(&gw_node->refcount))
+ gw_node = NULL;
+
+out:
+ rcu_read_unlock();
+ return gw_node;
+}
+
+/**
+ * batadv_gw_get_selected_orig() - Get originator of currently selected gateway
+ * @bat_priv: the bat priv with all the soft interface information
+ *
+ * Return: orig_node of selected gateway (with increased refcnt), NULL on errors
+ */
+struct batadv_orig_node *
+batadv_gw_get_selected_orig(struct batadv_priv *bat_priv)
+{
+ struct batadv_gw_node *gw_node;
+ struct batadv_orig_node *orig_node = NULL;
+
+ gw_node = batadv_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 (!kref_get_unless_zero(&orig_node->refcount))
+ orig_node = NULL;
+
+unlock:
+ rcu_read_unlock();
+out:
+ batadv_gw_node_put(gw_node);
+ return orig_node;
+}
+
+static void batadv_gw_select(struct batadv_priv *bat_priv,
+ struct batadv_gw_node *new_gw_node)
+{
+ struct batadv_gw_node *curr_gw_node;
+
+ spin_lock_bh(&bat_priv->gw.list_lock);
+
+ if (new_gw_node)
+ kref_get(&new_gw_node->refcount);
+
+ curr_gw_node = rcu_replace_pointer(bat_priv->gw.curr_gw, new_gw_node,
+ true);
+
+ batadv_gw_node_put(curr_gw_node);
+
+ spin_unlock_bh(&bat_priv->gw.list_lock);
+}
+
+/**
+ * batadv_gw_reselect() - force a gateway reselection
+ * @bat_priv: the bat priv with all the soft interface information
+ *
+ * Set a flag to remind the GW component to perform a new gateway reselection.
+ * However this function does not ensure that the current gateway is going to be
+ * deselected. The reselection mechanism may elect the same gateway once again.
+ *
+ * This means that invoking batadv_gw_reselect() does not guarantee a gateway
+ * change and therefore a uevent is not necessarily expected.
+ */
+void batadv_gw_reselect(struct batadv_priv *bat_priv)
+{
+ atomic_set(&bat_priv->gw.reselect, 1);
+}
+
+/**
+ * batadv_gw_check_client_stop() - check if client mode has been switched off
+ * @bat_priv: the bat priv with all the soft interface information
+ *
+ * This function assumes the caller has checked that the gw state *is actually
+ * changing*. This function is not supposed to be called when there is no state
+ * change.
+ */
+void batadv_gw_check_client_stop(struct batadv_priv *bat_priv)
+{
+ struct batadv_gw_node *curr_gw;
+
+ if (atomic_read(&bat_priv->gw.mode) != BATADV_GW_MODE_CLIENT)
+ return;
+
+ curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
+ if (!curr_gw)
+ return;
+
+ /* deselect the current gateway so that next time that client mode is
+ * enabled a proper GW_ADD event can be sent
+ */
+ batadv_gw_select(bat_priv, NULL);
+
+ /* if batman-adv is switching the gw client mode off and a gateway was
+ * already selected, send a DEL uevent
+ */
+ batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, NULL);
+
+ batadv_gw_node_put(curr_gw);
+}
+
+/**
+ * batadv_gw_election() - Elect the best gateway
+ * @bat_priv: the bat priv with all the soft interface information
+ */
+void batadv_gw_election(struct batadv_priv *bat_priv)
+{
+ struct batadv_gw_node *curr_gw = NULL;
+ struct batadv_gw_node *next_gw = NULL;
+ struct batadv_neigh_node *router = NULL;
+ struct batadv_neigh_ifinfo *router_ifinfo = NULL;
+ char gw_addr[18] = { '\0' };
+
+ if (atomic_read(&bat_priv->gw.mode) != BATADV_GW_MODE_CLIENT)
+ goto out;
+
+ if (!bat_priv->algo_ops->gw.get_best_gw_node)
+ goto out;
+
+ curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
+
+ if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw)
+ goto out;
+
+ /* if gw.reselect is set to 1 it means that a previous call to
+ * gw.is_eligible() said that we have a new best GW, therefore it can
+ * now be picked from the list and selected
+ */
+ next_gw = bat_priv->algo_ops->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 = batadv_orig_router_get(next_gw->orig_node,
+ BATADV_IF_DEFAULT);
+ if (!router) {
+ batadv_gw_reselect(bat_priv);
+ goto out;
+ }
+
+ router_ifinfo = batadv_neigh_ifinfo_get(router,
+ BATADV_IF_DEFAULT);
+ if (!router_ifinfo) {
+ batadv_gw_reselect(bat_priv);
+ goto out;
+ }
+ }
+
+ if (curr_gw && !next_gw) {
+ batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
+ "Removing selected gateway - no gateway in range\n");
+ batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL,
+ NULL);
+ } else if (!curr_gw && next_gw) {
+ batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
+ "Adding route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n",
+ next_gw->orig_node->orig,
+ next_gw->bandwidth_down / 10,
+ next_gw->bandwidth_down % 10,
+ next_gw->bandwidth_up / 10,
+ next_gw->bandwidth_up % 10,
+ router_ifinfo->bat_iv.tq_avg);
+ batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_ADD,
+ gw_addr);
+ } else {
+ batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
+ "Changing route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n",
+ next_gw->orig_node->orig,
+ next_gw->bandwidth_down / 10,
+ next_gw->bandwidth_down % 10,
+ next_gw->bandwidth_up / 10,
+ next_gw->bandwidth_up % 10,
+ router_ifinfo->bat_iv.tq_avg);
+ batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_CHANGE,
+ gw_addr);
+ }
+
+ batadv_gw_select(bat_priv, next_gw);
+
+out:
+ batadv_gw_node_put(curr_gw);
+ batadv_gw_node_put(next_gw);
+ batadv_neigh_node_put(router);
+ batadv_neigh_ifinfo_put(router_ifinfo);
+}
+
+/**
+ * batadv_gw_check_election() - Elect orig node as best gateway when eligible
+ * @bat_priv: the bat priv with all the soft interface information
+ * @orig_node: orig node which is to be checked
+ */
+void batadv_gw_check_election(struct batadv_priv *bat_priv,
+ struct batadv_orig_node *orig_node)
+{
+ struct batadv_orig_node *curr_gw_orig;
+
+ /* abort immediately if the routing algorithm does not support gateway
+ * election
+ */
+ if (!bat_priv->algo_ops->gw.is_eligible)
+ return;
+
+ curr_gw_orig = batadv_gw_get_selected_orig(bat_priv);
+ if (!curr_gw_orig)
+ goto reselect;
+
+ /* this node already is the gateway */
+ if (curr_gw_orig == orig_node)
+ goto out;
+
+ if (!bat_priv->algo_ops->gw.is_eligible(bat_priv, curr_gw_orig,
+ orig_node))
+ goto out;
+
+reselect:
+ batadv_gw_reselect(bat_priv);
+out:
+ batadv_orig_node_put(curr_gw_orig);
+}
+
+/**
+ * batadv_gw_node_add() - add gateway node to list of available gateways
+ * @bat_priv: the bat priv with all the soft interface information
+ * @orig_node: originator announcing gateway capabilities
+ * @gateway: announced bandwidth information
+ *
+ * Has to be called with the appropriate locks being acquired
+ * (gw.list_lock).
+ */
+static void batadv_gw_node_add(struct batadv_priv *bat_priv,
+ struct batadv_orig_node *orig_node,
+ struct batadv_tvlv_gateway_data *gateway)
+{
+ struct batadv_gw_node *gw_node;
+
+ lockdep_assert_held(&bat_priv->gw.list_lock);
+
+ if (gateway->bandwidth_down == 0)
+ return;
+
+ gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC);
+ if (!gw_node)
+ return;
+
+ kref_init(&gw_node->refcount);
+ INIT_HLIST_NODE(&gw_node->list);
+ kref_get(&orig_node->refcount);
+ gw_node->orig_node = orig_node;
+ gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);
+ gw_node->bandwidth_up = ntohl(gateway->bandwidth_up);
+
+ kref_get(&gw_node->refcount);
+ hlist_add_head_rcu(&gw_node->list, &bat_priv->gw.gateway_list);
+ bat_priv->gw.generation++;
+
+ batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
+ "Found new gateway %pM -> gw bandwidth: %u.%u/%u.%u MBit\n",
+ orig_node->orig,
+ ntohl(gateway->bandwidth_down) / 10,
+ ntohl(gateway->bandwidth_down) % 10,
+ ntohl(gateway->bandwidth_up) / 10,
+ ntohl(gateway->bandwidth_up) % 10);
+
+ /* don't return reference to new gw_node */
+ batadv_gw_node_put(gw_node);
+}
+
+/**
+ * batadv_gw_node_get() - retrieve gateway node from list of available gateways
+ * @bat_priv: the bat priv with all the soft interface information
+ * @orig_node: originator announcing gateway capabilities
+ *
+ * Return: gateway node if found or NULL otherwise.
+ */
+struct batadv_gw_node *batadv_gw_node_get(struct batadv_priv *bat_priv,
+ struct batadv_orig_node *orig_node)
+{
+ struct batadv_gw_node *gw_node_tmp, *gw_node = NULL;
+
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(gw_node_tmp, &bat_priv->gw.gateway_list,
+ list) {
+ if (gw_node_tmp->orig_node != orig_node)
+ continue;
+
+ if (!kref_get_unless_zero(&gw_node_tmp->refcount))
+ continue;
+
+ gw_node = gw_node_tmp;
+ break;
+ }
+ rcu_read_unlock();
+
+ return gw_node;
+}
+
+/**
+ * batadv_gw_node_update() - update list of available gateways with changed
+ * bandwidth information
+ * @bat_priv: the bat priv with all the soft interface information
+ * @orig_node: originator announcing gateway capabilities
+ * @gateway: announced bandwidth information
+ */
+void batadv_gw_node_update(struct batadv_priv *bat_priv,
+ struct batadv_orig_node *orig_node,
+ struct batadv_tvlv_gateway_data *gateway)
+{
+ struct batadv_gw_node *gw_node, *curr_gw = NULL;
+
+ spin_lock_bh(&bat_priv->gw.list_lock);
+ gw_node = batadv_gw_node_get(bat_priv, orig_node);
+ if (!gw_node) {
+ batadv_gw_node_add(bat_priv, orig_node, gateway);
+ spin_unlock_bh(&bat_priv->gw.list_lock);
+ goto out;
+ }
+ spin_unlock_bh(&bat_priv->gw.list_lock);
+
+ if (gw_node->bandwidth_down == ntohl(gateway->bandwidth_down) &&
+ gw_node->bandwidth_up == ntohl(gateway->bandwidth_up))
+ goto out;
+
+ batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
+ "Gateway bandwidth of originator %pM changed from %u.%u/%u.%u MBit to %u.%u/%u.%u MBit\n",
+ orig_node->orig,
+ gw_node->bandwidth_down / 10,
+ gw_node->bandwidth_down % 10,
+ gw_node->bandwidth_up / 10,
+ gw_node->bandwidth_up % 10,
+ ntohl(gateway->bandwidth_down) / 10,
+ ntohl(gateway->bandwidth_down) % 10,
+ ntohl(gateway->bandwidth_up) / 10,
+ ntohl(gateway->bandwidth_up) % 10);
+
+ gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);
+ gw_node->bandwidth_up = ntohl(gateway->bandwidth_up);
+
+ if (ntohl(gateway->bandwidth_down) == 0) {
+ batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
+ "Gateway %pM removed from gateway list\n",
+ orig_node->orig);
+
+ /* Note: We don't need a NULL check here, since curr_gw never
+ * gets dereferenced.
+ */
+ spin_lock_bh(&bat_priv->gw.list_lock);
+ if (!hlist_unhashed(&gw_node->list)) {
+ hlist_del_init_rcu(&gw_node->list);
+ batadv_gw_node_put(gw_node);
+ bat_priv->gw.generation++;
+ }
+ spin_unlock_bh(&bat_priv->gw.list_lock);
+
+ curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
+ if (gw_node == curr_gw)
+ batadv_gw_reselect(bat_priv);
+
+ batadv_gw_node_put(curr_gw);
+ }
+
+out:
+ batadv_gw_node_put(gw_node);
+}
+
+/**
+ * batadv_gw_node_delete() - Remove orig_node from gateway list
+ * @bat_priv: the bat priv with all the soft interface information
+ * @orig_node: orig node which is currently in process of being removed
+ */
+void batadv_gw_node_delete(struct batadv_priv *bat_priv,
+ struct batadv_orig_node *orig_node)
+{
+ struct batadv_tvlv_gateway_data gateway;
+
+ gateway.bandwidth_down = 0;
+ gateway.bandwidth_up = 0;
+
+ batadv_gw_node_update(bat_priv, orig_node, &gateway);
+}
+
+/**
+ * batadv_gw_node_free() - Free gateway information from soft interface
+ * @bat_priv: the bat priv with all the soft interface information
+ */
+void batadv_gw_node_free(struct batadv_priv *bat_priv)
+{
+ struct batadv_gw_node *gw_node;
+ struct hlist_node *node_tmp;
+
+ spin_lock_bh(&bat_priv->gw.list_lock);
+ hlist_for_each_entry_safe(gw_node, node_tmp,
+ &bat_priv->gw.gateway_list, list) {
+ hlist_del_init_rcu(&gw_node->list);
+ batadv_gw_node_put(gw_node);
+ bat_priv->gw.generation++;
+ }
+ spin_unlock_bh(&bat_priv->gw.list_lock);
+}
+
+/**
+ * batadv_gw_dump() - Dump gateways into a message
+ * @msg: Netlink message to dump into
+ * @cb: Control block containing additional options
+ *
+ * Return: Error code, or length of message
+ */
+int batadv_gw_dump(struct sk_buff *msg, struct netlink_callback *cb)
+{
+ struct batadv_hard_iface *primary_if = NULL;
+ struct net *net = sock_net(cb->skb->sk);
+ struct net_device *soft_iface;
+ struct batadv_priv *bat_priv;
+ int ifindex;
+ int ret;
+
+ ifindex = batadv_netlink_get_ifindex(cb->nlh,
+ BATADV_ATTR_MESH_IFINDEX);
+ if (!ifindex)
+ return -EINVAL;
+
+ soft_iface = dev_get_by_index(net, ifindex);
+ if (!soft_iface || !batadv_softif_is_valid(soft_iface)) {
+ ret = -ENODEV;
+ goto out;
+ }
+
+ bat_priv = netdev_priv(soft_iface);
+
+ primary_if = batadv_primary_if_get_selected(bat_priv);
+ if (!primary_if || primary_if->if_status != BATADV_IF_ACTIVE) {
+ ret = -ENOENT;
+ goto out;
+ }
+
+ if (!bat_priv->algo_ops->gw.dump) {
+ ret = -EOPNOTSUPP;
+ goto out;
+ }
+
+ bat_priv->algo_ops->gw.dump(msg, cb, bat_priv);
+
+ ret = msg->len;
+
+out:
+ batadv_hardif_put(primary_if);
+ dev_put(soft_iface);
+
+ return ret;
+}
+
+/**
+ * batadv_gw_dhcp_recipient_get() - check if a packet is a DHCP message
+ * @skb: the packet to check
+ * @header_len: a pointer to the batman-adv header size
+ * @chaddr: buffer where the client address will be stored. Valid
+ * only if the function returns BATADV_DHCP_TO_CLIENT
+ *
+ * This function may re-allocate the data buffer of the skb passed as argument.
+ *
+ * Return:
+ * - BATADV_DHCP_NO if the packet is not a dhcp message or if there was an error
+ * while parsing it
+ * - BATADV_DHCP_TO_SERVER if this is a message going to the DHCP server
+ * - BATADV_DHCP_TO_CLIENT if this is a message going to a DHCP client
+ */
+enum batadv_dhcp_recipient
+batadv_gw_dhcp_recipient_get(struct sk_buff *skb, unsigned int *header_len,
+ u8 *chaddr)
+{
+ enum batadv_dhcp_recipient ret = BATADV_DHCP_NO;
+ struct ethhdr *ethhdr;
+ struct iphdr *iphdr;
+ struct ipv6hdr *ipv6hdr;
+ struct udphdr *udphdr;
+ struct vlan_ethhdr *vhdr;
+ int chaddr_offset;
+ __be16 proto;
+ u8 *p;
+
+ /* check for ethernet header */
+ if (!pskb_may_pull(skb, *header_len + ETH_HLEN))
+ return BATADV_DHCP_NO;
+
+ ethhdr = eth_hdr(skb);
+ proto = ethhdr->h_proto;
+ *header_len += ETH_HLEN;
+
+ /* check for initial vlan header */
+ if (proto == htons(ETH_P_8021Q)) {
+ if (!pskb_may_pull(skb, *header_len + VLAN_HLEN))
+ return BATADV_DHCP_NO;
+
+ vhdr = vlan_eth_hdr(skb);
+ proto = vhdr->h_vlan_encapsulated_proto;
+ *header_len += VLAN_HLEN;
+ }
+
+ /* check for ip header */
+ switch (proto) {
+ case htons(ETH_P_IP):
+ if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr)))
+ return BATADV_DHCP_NO;
+
+ iphdr = (struct iphdr *)(skb->data + *header_len);
+ *header_len += iphdr->ihl * 4;
+
+ /* check for udp header */
+ if (iphdr->protocol != IPPROTO_UDP)
+ return BATADV_DHCP_NO;
+
+ break;
+ case htons(ETH_P_IPV6):
+ if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr)))
+ return BATADV_DHCP_NO;
+
+ ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len);
+ *header_len += sizeof(*ipv6hdr);
+
+ /* check for udp header */
+ if (ipv6hdr->nexthdr != IPPROTO_UDP)
+ return BATADV_DHCP_NO;
+
+ break;
+ default:
+ return BATADV_DHCP_NO;
+ }
+
+ if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr)))
+ return BATADV_DHCP_NO;
+
+ udphdr = (struct udphdr *)(skb->data + *header_len);
+ *header_len += sizeof(*udphdr);
+
+ /* check for bootp port */
+ switch (proto) {
+ case htons(ETH_P_IP):
+ if (udphdr->dest == htons(67))
+ ret = BATADV_DHCP_TO_SERVER;
+ else if (udphdr->source == htons(67))
+ ret = BATADV_DHCP_TO_CLIENT;
+ break;
+ case htons(ETH_P_IPV6):
+ if (udphdr->dest == htons(547))
+ ret = BATADV_DHCP_TO_SERVER;
+ else if (udphdr->source == htons(547))
+ ret = BATADV_DHCP_TO_CLIENT;
+ break;
+ }
+
+ chaddr_offset = *header_len + BATADV_DHCP_CHADDR_OFFSET;
+ /* store the client address if the message is going to a client */
+ if (ret == BATADV_DHCP_TO_CLIENT) {
+ if (!pskb_may_pull(skb, chaddr_offset + ETH_ALEN))
+ return BATADV_DHCP_NO;
+
+ /* check if the DHCP packet carries an Ethernet DHCP */
+ p = skb->data + *header_len + BATADV_DHCP_HTYPE_OFFSET;
+ if (*p != BATADV_DHCP_HTYPE_ETHERNET)
+ return BATADV_DHCP_NO;
+
+ /* check if the DHCP packet carries a valid Ethernet address */
+ p = skb->data + *header_len + BATADV_DHCP_HLEN_OFFSET;
+ if (*p != ETH_ALEN)
+ return BATADV_DHCP_NO;
+
+ ether_addr_copy(chaddr, skb->data + chaddr_offset);
+ }
+
+ return ret;
+}
+
+/**
+ * batadv_gw_out_of_range() - check if the dhcp request destination is the best
+ * gateway
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: the outgoing packet
+ *
+ * Check if the skb is a DHCP request and if it is sent to the current best GW
+ * server. Due to topology changes it may be the case that the GW server
+ * previously selected is not the best one anymore.
+ *
+ * This call might reallocate skb data.
+ * Must be invoked only when the DHCP packet is going TO a DHCP SERVER.
+ *
+ * Return: true if the packet destination is unicast and it is not the best gw,
+ * false otherwise.
+ */
+bool batadv_gw_out_of_range(struct batadv_priv *bat_priv,
+ struct sk_buff *skb)
+{
+ struct batadv_neigh_node *neigh_curr = NULL;
+ struct batadv_neigh_node *neigh_old = NULL;
+ struct batadv_orig_node *orig_dst_node = NULL;
+ struct batadv_gw_node *gw_node = NULL;
+ struct batadv_gw_node *curr_gw = NULL;
+ struct batadv_neigh_ifinfo *curr_ifinfo, *old_ifinfo;
+ struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
+ bool out_of_range = false;
+ u8 curr_tq_avg;
+ unsigned short vid;
+
+ vid = batadv_get_vid(skb, 0);
+
+ if (is_multicast_ether_addr(ethhdr->h_dest))
+ goto out;
+
+ orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source,
+ ethhdr->h_dest, vid);
+ if (!orig_dst_node)
+ goto out;
+
+ gw_node = batadv_gw_node_get(bat_priv, orig_dst_node);
+ if (!gw_node)
+ goto out;
+
+ switch (atomic_read(&bat_priv->gw.mode)) {
+ case BATADV_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 = BATADV_TQ_MAX_VALUE;
+ break;
+ case BATADV_GW_MODE_CLIENT:
+ curr_gw = batadv_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 = batadv_find_router(bat_priv, curr_gw->orig_node,
+ NULL);
+ if (!neigh_curr)
+ goto out;
+
+ curr_ifinfo = batadv_neigh_ifinfo_get(neigh_curr,
+ BATADV_IF_DEFAULT);
+ if (!curr_ifinfo)
+ goto out;
+
+ curr_tq_avg = curr_ifinfo->bat_iv.tq_avg;
+ batadv_neigh_ifinfo_put(curr_ifinfo);
+
+ break;
+ case BATADV_GW_MODE_OFF:
+ default:
+ goto out;
+ }
+
+ neigh_old = batadv_find_router(bat_priv, orig_dst_node, NULL);
+ if (!neigh_old)
+ goto out;
+
+ old_ifinfo = batadv_neigh_ifinfo_get(neigh_old, BATADV_IF_DEFAULT);
+ if (!old_ifinfo)
+ goto out;
+
+ if ((curr_tq_avg - old_ifinfo->bat_iv.tq_avg) > BATADV_GW_THRESHOLD)
+ out_of_range = true;
+ batadv_neigh_ifinfo_put(old_ifinfo);
+
+out:
+ batadv_orig_node_put(orig_dst_node);
+ batadv_gw_node_put(curr_gw);
+ batadv_gw_node_put(gw_node);
+ batadv_neigh_node_put(neigh_old);
+ batadv_neigh_node_put(neigh_curr);
+ return out_of_range;
+}