[v5,3/3] batman-adv: improved gateway tq-based selection
Commit Message
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>
---
Removed a useless decrement in is_type_dhcprequest()
gateway_client.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
gateway_client.h | 3 +-
main.h | 3 +-
soft-interface.c | 10 ++++-
4 files changed, 104 insertions(+), 6 deletions(-)
@@ -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_rcu(struct rcu_head *rcu)
{
struct gw_node *gw_node;
@@ -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;
}
@@ -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_ */
@@ -79,7 +79,6 @@
#define BCAST_QUEUE_LEN 256
#define BATMAN_QUEUE_LEN 256
-
enum uev_action {
UEV_ADD = 0,
UEV_DEL,
@@ -90,6 +89,8 @@ enum uev_type {
UEV_GW = 0
};
+#define GW_THRESHOLD 50
+
/*
* Debug Messages
*/
@@ -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>
@@ -569,6 +570,7 @@ 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;
int data_len = skb->len, ret;
short vid = -1;
bool do_bcast = false;
@@ -603,8 +605,10 @@ int interface_tx(struct sk_buff *skb, struct net_device *soft_iface)
/* TODO: check this for locks */
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;
@@ -612,6 +616,8 @@ int interface_tx(struct sk_buff *skb, struct net_device *soft_iface)
if (ret == 0)
do_bcast = true;
}
+ if (orig_node)
+ orig_node_free_ref(orig_node);
/* ethernet packet should be broadcasted */
if (do_bcast) {