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Commit 43676ab5 authored by Antonio Quartulli's avatar Antonio Quartulli Committed by Sven Eckelmann
Browse files

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: default avatarAntonio Quartulli <ordex@autistici.org>
Signed-off-by: default avatarMarek Lindner <lindner_marek@yahoo.de>
Signed-off-by: default avatarSven Eckelmann <sven@narfation.org>
parent 19595e05

net/batman-adv/gateway_client.c

+92 −2
Original line number Diff line number Diff line
@@ -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 @@ int gw_client_seq_print_text(struct seq_file *seq, void *offset) 
	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;

}

net/batman-adv/gateway_client.h

+2 −1
Original line number Diff line number Diff line
@@ -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_ */

net/batman-adv/main.h

+2 −1
Original line number Diff line number Diff line
@@ -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

 */

net/batman-adv/soft-interface.c

+8 −2
Original line number Diff line number Diff line
@@ -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 @@ static int interface_tx(struct sk_buff *skb, struct net_device *soft_iface) 
		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;

}