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xt_psd: move match functionality to helpers

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Reduce line count and to allow code reuse when IPv6 support will be
introduced.
This commit is contained in:
Florian Westphal
2012-08-16 13:05:05 +02:00
committed by Jan Engelhardt
parent 57d25f22f1
commit 093f3b0a97
1 changed files with 26 additions and 10 deletions
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36
extensions/xt_psd.c
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@@ -149,6 +149,29 @@ is_portscan(struct host *host, const struct xt_psd_info *psdinfo,
return false;
}
static struct host *host_get_next(struct host *h, struct host **last)
{
if (h->next != NULL)
*last = h;
return h->next;
}
static void ht_unlink(struct host **head, struct host *last)
{
if (last != NULL)
last->next = last->next->next;
else if (*head != NULL)
*head = (*head)->next;
}
static bool
entry_is_recent(const struct host *h, unsigned long delay_threshold,
unsigned long now)
{
return now - h->timestamp <= (delay_threshold * HZ) / 100 &&
time_after_eq(now, h->timestamp);
}
static bool
xt_psd_match(const struct sk_buff *pskb, struct xt_action_param *match)
{
@@ -216,16 +239,12 @@ xt_psd_match(const struct sk_buff *pskb, struct xt_action_param *match)
if (curr->src_addr.s_addr == addr.s_addr)
break;
count++;
if (curr->next != NULL)
last = curr;
curr = curr->next;
curr = host_get_next(curr, &last);
}
if (curr != NULL) {
/* We know this address, and the entry isn't too old. Update it. */
if (now - curr->timestamp <= (psdinfo->delay_threshold*HZ)/100 &&
time_after_eq(now, curr->timestamp)) {
if (entry_is_recent(curr, psdinfo->delay_threshold, now)) {
if (port_in_list(curr, proto, dest_port))
goto out_no_match;
/* TCP/ACK and/or TCP/RST to a new port? This could be an outgoing connection. */
@@ -240,10 +259,7 @@ xt_psd_match(const struct sk_buff *pskb, struct xt_action_param *match)
* remove from the hash table. We'll allocate a new entry instead since
* this one might get re-used too soon. */
curr->src_addr.s_addr = 0;
if (last != NULL)
last->next = last->next->next;
else if (*head != NULL)
*head = (*head)->next;
ht_unlink(head, last);
last = NULL;
}