/*
* Copyright (C) 2009-2011 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 "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 = 2 * PURGE_TIMEOUT * HZ;
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%s, MainIF/MAC: %s/%pM (%s)]\n",
"Gateway", "#", TQ_MAX_VALUE, "Nexthop",
"outgoingIF", SOURCE_VERSION, REVISION_VERSION_STR,
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:
* - octect 1: option type
* - octect 2: option data len (only if type != 255 and 0)
* - octect 3: option data */
while (*p != 255 && !ret) {
/* p now points to the first octect: option type */
if (*p == 53) {
/* type 53 is the message type option.
* Jump the len octect and go to the data octect */
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;
}
int gw_is_target(struct bat_priv *bat_priv, struct sk_buff *skb,
struct orig_node *old_gw)
{
struct ethhdr *ethhdr;
struct iphdr *iphdr;
struct ipv6hdr *ipv6hdr;
struct udphdr *udphdr;
struct gw_node *curr_gw;
struct neigh_node *neigh_curr = NULL, *neigh_old = NULL;
unsigned int header_len = 0;
int ret = 1;
if (atomic_read(&bat_priv->gw_mode) == GW_MODE_OFF)
return 0;
/* check for ethernet header */
if (!pskb_may_pull(skb, header_len + ETH_HLEN))
return 0;
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 0;
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 0;
iphdr = (struct iphdr *)(skb->data + header_len);
header_len += iphdr->ihl * 4;
/* check for udp header */
if (iphdr->protocol != IPPROTO_UDP)
return 0;
break;
case ETH_P_IPV6:
if (!pskb_may_pull(skb, header_len + sizeof(*ipv6hdr)))
return 0;
ipv6hdr = (struct ipv6hdr *)(skb->data + header_len);
header_len += sizeof(*ipv6hdr);
/* check for udp header */
if (ipv6hdr->nexthdr != IPPROTO_UDP)
return 0;
break;
default:
return 0;
}
if (!pskb_may_pull(skb, header_len + sizeof(*udphdr)))
return 0;
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 0;
if ((ntohs(ethhdr->h_proto) == ETH_P_IPV6) &&
(ntohs(udphdr->dest) != 547))
return 0;
if (atomic_read(&bat_priv->gw_mode) == GW_MODE_SERVER)
return -1;
curr_gw = gw_get_selected_gw_node(bat_priv);
if (!curr_gw)
return 0;
/* If old_gw != NULL then this packet is unicast.
* So, at this point we have to check the message type: if it is a
* DHCPREQUEST we have to decide whether to drop it or not */
if (old_gw && curr_gw->orig_node != old_gw) {
if (is_type_dhcprequest(skb, header_len)) {
/* 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);
neigh_old = find_router(bat_priv, old_gw, NULL);
if (!neigh_curr || !neigh_old)
goto free_neigh;
if (neigh_curr->tq_avg - neigh_old->tq_avg <
GW_THRESHOLD)
ret = -1;
}
}
free_neigh:
if (neigh_old)
neigh_node_free_ref(neigh_old);
if (neigh_curr)
neigh_node_free_ref(neigh_curr);
if (curr_gw)
gw_node_free_ref(curr_gw);
return ret;
}
