/* Copyright (C) 2009-2013 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 "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 BATADV_DHCP_OPTIONS_OFFSET 240 #define BATADV_DHCP_REQUEST 3 static void batadv_gw_node_free_ref(struct batadv_gw_node *gw_node) { if (atomic_dec_and_test(&gw_node->refcount)) kfree_rcu(gw_node, rcu); } 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 (!atomic_inc_not_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 (!atomic_inc_not_zero(&orig_node->refcount)) orig_node = NULL; unlock: rcu_read_unlock(); out: if (gw_node) batadv_gw_node_free_ref(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 && !atomic_inc_not_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_free_ref(curr_gw_node); spin_unlock_bh(&bat_priv->gw.list_lock); } void batadv_gw_deselect(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_gw_node *gw_node, *curr_gw = NULL; uint32_t max_gw_factor = 0, tmp_gw_factor = 0; uint32_t gw_divisor; uint8_t max_tq = 0; int down, up; uint8_t tq_avg; struct batadv_orig_node *orig_node; gw_divisor = BATADV_TQ_LOCAL_WINDOW_SIZE * BATADV_TQ_LOCAL_WINDOW_SIZE; gw_divisor *= 64; rcu_read_lock(); hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) { if (gw_node->deleted) continue; orig_node = gw_node->orig_node; router = batadv_orig_node_get_router(orig_node); if (!router) continue; if (!atomic_inc_not_zero(&gw_node->refcount)) goto next; tq_avg = router->tq_avg; switch (atomic_read(&bat_priv->gw_sel_class)) { case 1: /* fast connection */ batadv_gw_bandwidth_to_kbit(orig_node->gw_flags, &down, &up); tmp_gw_factor = tq_avg * tq_avg * down * 100 * 100; tmp_gw_factor /= gw_divisor; if ((tmp_gw_factor > max_gw_factor) || ((tmp_gw_factor == max_gw_factor) && (tq_avg > max_tq))) { if (curr_gw) batadv_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 (tq_avg > max_tq) { if (curr_gw) batadv_gw_node_free_ref(curr_gw); curr_gw = gw_node; atomic_inc(&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_free_ref(gw_node); next: batadv_neigh_node_free_ref(router); } 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; /* 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_free_ref(curr_gw); } void batadv_gw_election(struct batadv_priv *bat_priv) { struct batadv_gw_node *curr_gw = NULL, *next_gw = NULL; struct batadv_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) != 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_node_get_router(next_gw->orig_node); if (!router) { batadv_gw_deselect(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 (gw_flags: %i, tq: %i)\n", next_gw->orig_node->orig, next_gw->orig_node->gw_flags, router->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 (gw_flags: %i, tq: %i)\n", next_gw->orig_node->orig, next_gw->orig_node->gw_flags, router->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_free_ref(curr_gw); if (next_gw) batadv_gw_node_free_ref(next_gw); if (router) batadv_neigh_node_free_ref(router); } void batadv_gw_check_election(struct batadv_priv *bat_priv, struct batadv_orig_node *orig_node) { struct batadv_orig_node *curr_gw_orig; struct batadv_neigh_node *router_gw = NULL, *router_orig = NULL; uint8_t gw_tq_avg, orig_tq_avg; curr_gw_orig = batadv_gw_get_selected_orig(bat_priv); if (!curr_gw_orig) goto deselect; router_gw = batadv_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 = batadv_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; 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); deselect: batadv_gw_deselect(bat_priv); out: if (curr_gw_orig) batadv_orig_node_free_ref(curr_gw_orig); if (router_gw) batadv_neigh_node_free_ref(router_gw); if (router_orig) batadv_neigh_node_free_ref(router_orig); return; } static void batadv_gw_node_add(struct batadv_priv *bat_priv, struct batadv_orig_node *orig_node, uint8_t new_gwflags) { struct batadv_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); batadv_gw_bandwidth_to_kbit(new_gwflags, &down, &up); batadv_dbg(BATADV_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 batadv_gw_node_update(struct batadv_priv *bat_priv, struct batadv_orig_node *orig_node, uint8_t new_gwflags) { struct batadv_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 = batadv_gw_get_selected_gw_node(bat_priv); rcu_read_lock(); hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) { if (gw_node->orig_node != orig_node) continue; batadv_dbg(BATADV_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 == BATADV_NO_FLAGS) { gw_node->deleted = jiffies; batadv_dbg(BATADV_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 == BATADV_NO_FLAGS) goto unlock; batadv_gw_node_add(bat_priv, orig_node, new_gwflags); goto unlock; deselect: batadv_gw_deselect(bat_priv); unlock: rcu_read_unlock(); if (curr_gw) batadv_gw_node_free_ref(curr_gw); } void batadv_gw_node_delete(struct batadv_priv *bat_priv, struct batadv_orig_node *orig_node) { batadv_gw_node_update(bat_priv, orig_node, 0); } void batadv_gw_node_purge(struct batadv_priv *bat_priv) { struct batadv_gw_node *gw_node, *curr_gw; struct hlist_node *node_tmp; unsigned long timeout = msecs_to_jiffies(2 * BATADV_PURGE_TIMEOUT); int do_deselect = 0; curr_gw = batadv_gw_get_selected_gw_node(bat_priv); spin_lock_bh(&bat_priv->gw.list_lock); hlist_for_each_entry_safe(gw_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) == BATADV_MESH_ACTIVE) continue; if (curr_gw == gw_node) do_deselect = 1; hlist_del_rcu(&gw_node->list); batadv_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) batadv_gw_deselect(bat_priv); if (curr_gw) batadv_gw_node_free_ref(curr_gw); } /* 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; int down, up, ret = -1; batadv_gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags, &down, &up); router = batadv_orig_node_get_router(gw_node->orig_node); if (!router) goto out; curr_gw = batadv_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")); batadv_neigh_node_free_ref(router); if (curr_gw) batadv_gw_node_free_ref(curr_gw); out: 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]: gw_class ... [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) { if (gw_node->deleted) continue; /* 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_free_ref(primary_if); return 0; } /* this call might reallocate skb data */ static bool batadv_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 + BATADV_DHCP_OPTIONS_OFFSET + 1) goto out; p = skb->data + header_len + BATADV_DHCP_OPTIONS_OFFSET; pkt_len -= header_len + BATADV_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 == BATADV_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 < 1 + (*p)) goto out; pkt_len -= 1 + (*p); p += 1 + (*p); } } out: return ret; } /* this call might reallocate skb data */ bool batadv_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; /* skb->data might have been reallocated by pskb_may_pull() */ ethhdr = (struct ethhdr *)skb->data; if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) ethhdr = (struct ethhdr *)(skb->data + VLAN_HLEN); 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; } /* this call might reallocate skb data */ bool batadv_gw_out_of_range(struct batadv_priv *bat_priv, struct sk_buff *skb) { struct batadv_neigh_node *neigh_curr = NULL, *neigh_old = NULL; struct batadv_orig_node *orig_dst_node = NULL; struct batadv_gw_node *curr_gw = NULL; struct ethhdr *ethhdr; bool ret, out_of_range = false; unsigned int header_len = 0; uint8_t curr_tq_avg; ret = batadv_gw_is_dhcp_target(skb, &header_len); if (!ret) goto out; ethhdr = (struct ethhdr *)skb->data; orig_dst_node = batadv_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 = batadv_is_type_dhcprequest(skb, header_len); if (!ret) 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_tq_avg = neigh_curr->tq_avg; 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; if (curr_tq_avg - neigh_old->tq_avg > BATADV_GW_THRESHOLD) out_of_range = true; out: if (orig_dst_node) batadv_orig_node_free_ref(orig_dst_node); if (curr_gw) batadv_gw_node_free_ref(curr_gw); if (neigh_old) batadv_neigh_node_free_ref(neigh_old); if (neigh_curr) batadv_neigh_node_free_ref(neigh_curr); return out_of_range; }