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batman-adv: improved gateway tq-based selection 

If a client issues a DHCPREQUEST for renewal, the packet is dropped
if the old destination (the old gateway for the client) TQ is smaller
than the current best gateway TQ less GW_THRESHOLD

Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
This commit is contained in:
Antonio Quartulli 2011-04-26 21:31:45 +02:00 committed by Sven Eckelmann
parent 19595e054d
commit 43676ab590
4 changed files with 104 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

94
net/batman-adv/gateway_client.c
View File

@ -25,11 +25,17 @@
#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))
@ -509,14 +515,75 @@ out:
return ret;
}
int gw_is_target(struct bat_priv *bat_priv, struct sk_buff *skb)
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;
@ -584,7 +651,30 @@ int gw_is_target(struct bat_priv *bat_priv, struct sk_buff *skb)
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 1;
return ret;
}

3
net/batman-adv/gateway_client.h
View File

@ -31,6 +31,7 @@ void gw_node_update(struct bat_priv *bat_priv,
void gw_node_delete(struct bat_priv *bat_priv, struct orig_node *orig_node);
void gw_node_purge(struct bat_priv *bat_priv);
int gw_client_seq_print_text(struct seq_file *seq, void *offset);
int gw_is_target(struct bat_priv *bat_priv, struct sk_buff *skb);
int gw_is_target(struct bat_priv *bat_priv, struct sk_buff *skb,
struct orig_node *old_gw);
#endif /* _NET_BATMAN_ADV_GATEWAY_CLIENT_H_ */

3
net/batman-adv/main.h
View File

@ -91,7 +91,6 @@ enum mesh_state {
#define BCAST_QUEUE_LEN 256
#define BATMAN_QUEUE_LEN 256
enum uev_action {
UEV_ADD = 0,
UEV_DEL,
@ -102,6 +101,8 @@ enum uev_type {
UEV_GW = 0
};
#define GW_THRESHOLD 50
/*
* Debug Messages
*/

10
net/batman-adv/soft-interface.c
View File

@ -30,6 +30,7 @@
#include "gateway_common.h"
#include "gateway_client.h"
#include "bat_sysfs.h"
#include "originator.h"
#include <linux/slab.h>
#include <linux/ethtool.h>
#include <linux/etherdevice.h>
@ -561,6 +562,7 @@ static int interface_tx(struct sk_buff *skb, struct net_device *soft_iface)
struct bcast_packet *bcast_packet;
struct vlan_ethhdr *vhdr;
struct softif_neigh *curr_softif_neigh = NULL;
struct orig_node *orig_node = NULL;
int data_len = skb->len, ret;
short vid = -1;
bool do_bcast = false;
@ -595,8 +597,10 @@ static int interface_tx(struct sk_buff *skb, struct net_device *soft_iface)
/* Register the client MAC in the transtable */
tt_local_add(soft_iface, ethhdr->h_source);
if (is_multicast_ether_addr(ethhdr->h_dest)) {
ret = gw_is_target(bat_priv, skb);
orig_node = transtable_search(bat_priv, ethhdr->h_dest);
if (is_multicast_ether_addr(ethhdr->h_dest) ||
(orig_node && orig_node->gw_flags)) {
ret = gw_is_target(bat_priv, skb, orig_node);
if (ret < 0)
goto dropped;
@ -656,6 +660,8 @@ end:
softif_neigh_free_ref(curr_softif_neigh);
if (primary_if)
hardif_free_ref(primary_if);
if (orig_node)
orig_node_free_ref(orig_node);
return NETDEV_TX_OK;
}