xt_psd: move match functionality to helpers

Reduce line count and to allow code reuse when IPv6 support will be
introduced.

diff --git a/extensions/xt_psd.c b/extensions/xt_psd.c
index 197dbf9d8ec85db1c26fd79001c06bc3c280489e..dbe422b1a68ef3acbb870b5ce36dae55f7dca01d 100644 (file)
--- a/extensions/xt_psd.c
+++ b/extensions/xt_psd.c
@@ -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;
        }