diff options
Diffstat (limited to 'net/batman-adv/gateway_client.c')
| -rw-r--r-- | net/batman-adv/gateway_client.c | 844 |
1 files changed, 844 insertions, 0 deletions
diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c new file mode 100644 index 000000000..0c59fefc1 --- /dev/null +++ b/net/batman-adv/gateway_client.c @@ -0,0 +1,844 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (C) 2009-2018 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, see <http://www.gnu.org/licenses/>. + */ + +#include "gateway_client.h" +#include "main.h" + +#include <linux/atomic.h> +#include <linux/byteorder/generic.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/seq_file.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 "gateway_common.h" +#include "hard-interface.h" +#include "log.h" +#include "netlink.h" +#include "originator.h" +#include "routing.h" +#include "soft-interface.h" +#include "sysfs.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 + */ +static 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_node_put() - decrement the gw_node refcounter and possibly release + * it + * @gw_node: gateway node to free + */ +void batadv_gw_node_put(struct batadv_gw_node *gw_node) +{ + kref_put(&gw_node->refcount, batadv_gw_node_release); +} + +/** + * 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: + if (gw_node) + 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_dereference_protected(bat_priv->gw.curr_gw, 1); + rcu_assign_pointer(bat_priv->gw.curr_gw, new_gw_node); + + if (curr_gw_node) + 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: + if (curr_gw) + batadv_gw_node_put(curr_gw); + if (next_gw) + batadv_gw_node_put(next_gw); + if (router) + batadv_neigh_node_put(router); + if (router_ifinfo) + 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: + if (curr_gw_orig) + 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); + + 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); + } + 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); + + if (curr_gw) + batadv_gw_node_put(curr_gw); + } + +out: + if (gw_node) + 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); + } + spin_unlock_bh(&bat_priv->gw.list_lock); +} + +#ifdef CONFIG_BATMAN_ADV_DEBUGFS + +/** + * batadv_gw_client_seq_print_text() - Print the gateway table in a seq file + * @seq: seq file to print on + * @offset: not used + * + * Return: always 0 + */ +int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset) +{ + struct net_device *net_dev = (struct net_device *)seq->private; + struct batadv_priv *bat_priv = netdev_priv(net_dev); + struct batadv_hard_iface *primary_if; + + primary_if = batadv_seq_print_text_primary_if_get(seq); + if (!primary_if) + return 0; + + seq_printf(seq, "[B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s %s)]\n", + BATADV_SOURCE_VERSION, primary_if->net_dev->name, + primary_if->net_dev->dev_addr, net_dev->name, + bat_priv->algo_ops->name); + + batadv_hardif_put(primary_if); + + if (!bat_priv->algo_ops->gw.print) { + seq_puts(seq, + "No printing function for this routing protocol\n"); + return 0; + } + + bat_priv->algo_ops->gw.print(bat_priv, seq); + + return 0; +} +#endif + +/** + * 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: + if (primary_if) + batadv_hardif_put(primary_if); + if (soft_iface) + 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: + if (orig_dst_node) + batadv_orig_node_put(orig_dst_node); + if (curr_gw) + batadv_gw_node_put(curr_gw); + if (gw_node) + batadv_gw_node_put(gw_node); + if (neigh_old) + batadv_neigh_node_put(neigh_old); + if (neigh_curr) + batadv_neigh_node_put(neigh_curr); + return out_of_range; +} |