/* Copyright (C) 2009-2016 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/etherdevice.h> #include <linux/fs.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/netdevice.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 "gateway_common.h" #include "hard-interface.h" #include "originator.h" #include "packet.h" #include "routing.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 */ static void batadv_gw_node_put(struct batadv_gw_node *gw_node) { kref_put(&gw_node->refcount, batadv_gw_node_release); } static 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; } 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_unless_zero(&new_gw_node->refcount)) new_gw_node = NULL; 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); } static struct batadv_gw_node * batadv_gw_get_best_gw_node(struct batadv_priv *bat_priv) { struct batadv_neigh_node *router; struct batadv_neigh_ifinfo *router_ifinfo; struct batadv_gw_node *gw_node, *curr_gw = NULL; u64 max_gw_factor = 0; u64 tmp_gw_factor = 0; u8 max_tq = 0; u8 tq_avg; struct batadv_orig_node *orig_node; rcu_read_lock(); hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) { orig_node = gw_node->orig_node; router = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT); if (!router) continue; router_ifinfo = batadv_neigh_ifinfo_get(router, BATADV_IF_DEFAULT); if (!router_ifinfo) goto next; if (!kref_get_unless_zero(&gw_node->refcount)) goto next; tq_avg = router_ifinfo->bat_iv.tq_avg; switch (atomic_read(&bat_priv->gw_sel_class)) { case 1: /* fast connection */ tmp_gw_factor = tq_avg * tq_avg; tmp_gw_factor *= gw_node->bandwidth_down; tmp_gw_factor *= 100 * 100; tmp_gw_factor >>= 18; if ((tmp_gw_factor > max_gw_factor) || ((tmp_gw_factor == max_gw_factor) && (tq_avg > max_tq))) { if (curr_gw) batadv_gw_node_put(curr_gw); curr_gw = gw_node; kref_get(&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 (tq_avg > max_tq) { if (curr_gw) batadv_gw_node_put(curr_gw); curr_gw = gw_node; kref_get(&curr_gw->refcount); } break; } if (tq_avg > max_tq) max_tq = tq_avg; if (tmp_gw_factor > max_gw_factor) max_gw_factor = tmp_gw_factor; batadv_gw_node_put(gw_node); next: batadv_neigh_node_put(router); if (router_ifinfo) batadv_neigh_ifinfo_put(router_ifinfo); } rcu_read_unlock(); return curr_gw; } /** * 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); } 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; curr_gw = batadv_gw_get_selected_gw_node(bat_priv); if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw) goto out; next_gw = batadv_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); } void batadv_gw_check_election(struct batadv_priv *bat_priv, struct batadv_orig_node *orig_node) { struct batadv_neigh_ifinfo *router_orig_tq = NULL; struct batadv_neigh_ifinfo *router_gw_tq = NULL; struct batadv_orig_node *curr_gw_orig; struct batadv_neigh_node *router_gw = NULL; struct batadv_neigh_node *router_orig = NULL; u8 gw_tq_avg, orig_tq_avg; curr_gw_orig = batadv_gw_get_selected_orig(bat_priv); if (!curr_gw_orig) goto reselect; router_gw = batadv_orig_router_get(curr_gw_orig, BATADV_IF_DEFAULT); if (!router_gw) goto reselect; router_gw_tq = batadv_neigh_ifinfo_get(router_gw, BATADV_IF_DEFAULT); if (!router_gw_tq) goto reselect; /* this node already is the gateway */ if (curr_gw_orig == orig_node) goto out; router_orig = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT); if (!router_orig) goto out; router_orig_tq = batadv_neigh_ifinfo_get(router_orig, BATADV_IF_DEFAULT); if (!router_orig_tq) goto out; gw_tq_avg = router_gw_tq->bat_iv.tq_avg; orig_tq_avg = router_orig_tq->bat_iv.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; batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "Restarting gateway selection: better gateway found (tq curr: %i, tq new: %i)\n", gw_tq_avg, orig_tq_avg); reselect: batadv_gw_reselect(bat_priv); out: if (curr_gw_orig) batadv_orig_node_put(curr_gw_orig); if (router_gw) batadv_neigh_node_put(router_gw); if (router_orig) batadv_neigh_node_put(router_orig); if (router_gw_tq) batadv_neigh_ifinfo_put(router_gw_tq); if (router_orig_tq) batadv_neigh_ifinfo_put(router_orig_tq); } /** * 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 */ 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; if (gateway->bandwidth_down == 0) return; if (!kref_get_unless_zero(&orig_node->refcount)) return; gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC); if (!gw_node) { batadv_orig_node_put(orig_node); return; } INIT_HLIST_NODE(&gw_node->list); gw_node->orig_node = orig_node; gw_node->bandwidth_down = ntohl(gateway->bandwidth_down); gw_node->bandwidth_up = ntohl(gateway->bandwidth_up); kref_init(&gw_node->refcount); 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); 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); } /** * 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. */ static 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.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; gw_node = batadv_gw_node_get(bat_priv, orig_node); if (!gw_node) { batadv_gw_node_add(bat_priv, orig_node, gateway); goto out; } 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); } 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); } 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.list, list) { hlist_del_init_rcu(&gw_node->list); batadv_gw_node_put(gw_node); } spin_unlock_bh(&bat_priv->gw.list_lock); } /* fails if orig_node has no router */ static int batadv_write_buffer_text(struct batadv_priv *bat_priv, struct seq_file *seq, const struct batadv_gw_node *gw_node) { struct batadv_gw_node *curr_gw; struct batadv_neigh_node *router; struct batadv_neigh_ifinfo *router_ifinfo = NULL; int ret = -1; router = batadv_orig_router_get(gw_node->orig_node, BATADV_IF_DEFAULT); if (!router) goto out; router_ifinfo = batadv_neigh_ifinfo_get(router, BATADV_IF_DEFAULT); if (!router_ifinfo) goto out; curr_gw = batadv_gw_get_selected_gw_node(bat_priv); seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %u.%u/%u.%u MBit\n", (curr_gw == gw_node ? "=>" : " "), gw_node->orig_node->orig, router_ifinfo->bat_iv.tq_avg, router->addr, router->if_incoming->net_dev->name, gw_node->bandwidth_down / 10, gw_node->bandwidth_down % 10, gw_node->bandwidth_up / 10, gw_node->bandwidth_up % 10); ret = seq_has_overflowed(seq) ? -1 : 0; if (curr_gw) batadv_gw_node_put(curr_gw); out: if (router_ifinfo) batadv_neigh_ifinfo_put(router_ifinfo); if (router) batadv_neigh_node_put(router); return ret; } 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; struct batadv_gw_node *gw_node; int gw_count = 0; primary_if = batadv_seq_print_text_primary_if_get(seq); if (!primary_if) goto out; seq_printf(seq, " %-12s (%s/%i) %17s [%10s]: advertised uplink bandwidth ... [B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n", "Gateway", "#", BATADV_TQ_MAX_VALUE, "Nexthop", "outgoingIF", BATADV_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, &bat_priv->gw.list, list) { /* fails if orig_node has no router */ if (batadv_write_buffer_text(bat_priv, seq, gw_node) < 0) continue; gw_count++; } rcu_read_unlock(); if (gw_count == 0) seq_puts(seq, "No gateways in range ...\n"); out: if (primary_if) batadv_hardif_put(primary_if); return 0; } /** * 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 && pskb_may_pull(skb, chaddr_offset + ETH_ALEN)) { /* 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 gw * @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); 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; }