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batman-adv: refactoring gateway handling code

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Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Acked-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
This commit is contained in:
Marek Lindner
2011-09-08 13:12:53 +02:00
committed by Sven Eckelmann
parent 25a92b138d
commit be7af5cf9c
3 changed files with 125 additions and 74 deletions
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151
net/batman-adv/gateway_client.c
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@@ -25,6 +25,7 @@
#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>
@@ -572,108 +573,142 @@ out:
return ret;
}
int gw_is_target(struct bat_priv *bat_priv, struct sk_buff *skb,
struct orig_node *old_gw)
bool gw_is_dhcp_target(struct sk_buff *skb, unsigned int *header_len)
{
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;
if (!pskb_may_pull(skb, *header_len + ETH_HLEN))
return false;
ethhdr = (struct ethhdr *)skb->data;
header_len += ETH_HLEN;
*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;
if (!pskb_may_pull(skb, *header_len + VLAN_HLEN))
return false;
ethhdr = (struct ethhdr *)(skb->data + VLAN_HLEN);
header_len += 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;
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 0;
return false;
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);
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 0;
return false;
break;
default:
return 0;
return false;
}
if (!pskb_may_pull(skb, header_len + sizeof(*udphdr)))
return 0;
udphdr = (struct udphdr *)(skb->data + header_len);
header_len += sizeof(*udphdr);
if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr)))
return false;
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;
return false;
if ((ntohs(ethhdr->h_proto) == ETH_P_IPV6) &&
(ntohs(udphdr->dest) != 547))
return 0;
return false;
if (atomic_read(&bat_priv->gw_mode) == GW_MODE_SERVER)
return -1;
return true;
}
curr_gw = gw_get_selected_gw_node(bat_priv);
if (!curr_gw)
return 0;
bool gw_out_of_range(struct bat_priv *bat_priv,
struct sk_buff *skb, struct ethhdr *ethhdr)
{
struct neigh_node *neigh_curr = NULL, *neigh_old = NULL;
struct orig_node *orig_dst_node = NULL;
struct gw_node *curr_gw = NULL;
bool ret, out_of_range = false;
unsigned int header_len = 0;
uint8_t curr_tq_avg;
/* 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;
}
ret = gw_is_dhcp_target(skb, &header_len);
if (!ret)
goto out;
orig_dst_node = 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 = is_type_dhcprequest(skb, header_len);
if (!ret)
goto out;
switch (atomic_read(&bat_priv->gw_mode)) {
case 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 = TQ_MAX_VALUE;
break;
case GW_MODE_CLIENT:
curr_gw = 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 = find_router(bat_priv, curr_gw->orig_node, NULL);
if (!neigh_curr)
goto out;
curr_tq_avg = neigh_curr->tq_avg;
break;
case GW_MODE_OFF:
default:
goto out;
}
free_neigh:
neigh_old = find_router(bat_priv, orig_dst_node, NULL);
if (!!neigh_old)
goto out;
if (curr_tq_avg - neigh_old->tq_avg > GW_THRESHOLD)
out_of_range = true;
out:
if (orig_dst_node)
orig_node_free_ref(orig_dst_node);
if (curr_gw)
gw_node_free_ref(curr_gw);
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;
return out_of_range;
}