[Aggregator] Handle AP list

infrastructure-centred/owlps-aggregator/owlps-aggregator.h

@@ -63,6 +63,17 @@ typedef struct _couple_list
 } couple_list ;
 
 
+/* Linked list of the known APs */
+typedef struct _ap_list
+{
+  unsigned char mac_address_bytes[6] ;
+  struct timeval last_seen ;
+
+  struct _ap_list *previous ;
+  struct _ap_list *next ;
+} ap_list ;
+
+
 /* Function headers */
 void initialise_configuration(int argc, char **argv) ;
 void parse_config_file(int argc, char **argv) ;
@@ -71,13 +82,28 @@ void check_configuration(void) ;
 
 int read_loop(int sockfd) ;
 void got_couple_info(couple_message message) ;
+
+void* monitor_couples(void) ;
 void free_couple_list(void) ;
 #ifdef DEBUG
 void print_couple_list(void) ;
 void print_couple_info(couple_info_list *info) ;
 #endif // DEBUG
 
-void* monitor_couples(void) ;
+void update_ap(unsigned char mac_address_bytes[6]) ;
+ap_list* find_ap(unsigned char mac_address_bytes[6]) ;
+void add_ap_front(unsigned char mac_address_bytes[6]) ;
+void update_ap_seen(ap_list *ap) ;
+void push_ap(ap_list *ap) ;
+
+void monitor_aps(void) ;
+void delete_old_aps(void) ;
+void delete_ap(ap_list *ap) ;
+void unlink_ap(ap_list *ap) ;
+void order_send(ap_list *ap) ;
+void move_ap_front(ap_list *ap) ;
+void free_ap_list(void) ;
+
 char* ip_bytes_to_string(unsigned char *ip_binary) ;
 void print_usage(void) ;
 

infrastructure-centred/owlps-aggregator/owlps-aggregatord.c

@@ -5,11 +5,15 @@
 
 #include "owlps-aggregator.h"
 
+#include <assert.h>
+
 
 
 char *program_name = NULL ;
 cfg_t *cfg = NULL ; // Configuration structure
 couple_list *couples = NULL ; // Computed data list
+ap_list *aps = NULL ;
+unsigned int nb_aps = 0 ;
 
 
 
@@ -49,6 +53,7 @@ int main(int argc, char **argv)
 
   (void) close(sockfd) ; // Close socket
   free_couple_list() ;
+  free_ap_list() ;
   cfg_free(cfg) ; // Clean configuration
 
   printf("%s: end.\n", program_name) ;
@@ -597,6 +602,169 @@ void free_couple_list()
 
 
 
+/*
+ * Updates the timestamp of the AP with the given MAC address if it is in
+ * the AP list, or add a new AP with this MAC address to the AP list.
+ */
+void update_ap(unsigned char mac_address_bytes[6])
+{
+  ap_list *found ;
+
+  if ((found = find_ap(mac_address_bytes)) == NULL)
+    add_ap_front(mac_address_bytes) ;
+
+  else
+    update_ap_seen(found) ;
+}
+
+
+/*
+ * Searches the AP list for an AP with the given MAC address and returns
+ * it.
+ */
+ap_list* find_ap(unsigned char mac_address_bytes[6])
+{
+  ap_list *found = aps ;
+
+  while (found != NULL)
+    {
+      if (mac_cmp(found->mac_address_bytes, mac_address_bytes))
+        return found ;
+      found = found->next ;
+    }
+
+  return NULL ;
+}
+
+
+/* Adds a new AP in front of the AP list. */
+inline void add_ap_front(unsigned char mac_address_bytes[6])
+{
+  ap_list *ap = malloc(sizeof(ap_list)) ;
+  memcpy(ap->mac_address_bytes, mac_address_bytes, 6) ;
+  update_ap_seen(ap) ;
+  push_ap(ap) ;
+  ++nb_aps ;
+}
+
+
+/* Updates the timestamp of the given AP. */
+inline void update_ap_seen(ap_list *ap)
+{
+  assert(ap) ;
+  gettimeofday(&ap->last_seen, NULL) ;
+}
+
+
+/*
+ * Puts an existing AP in front of the AP list. The AP must not be in
+ * the list yet.
+ */
+inline void push_ap(ap_list *ap)
+{
+  assert(ap) ;
+  ap->previous = NULL ;
+  ap->next = aps ;
+  if (aps != NULL)
+    aps->previous = ap ;
+  aps = ap ;
+}
+
+
+
+/*
+ * Monitors the AP list: sends orders to APs following their order in
+ * the list, and deletes old APs.
+ */
+void monitor_aps()
+{
+  while (run)
+    {
+      delete_old_aps() ;
+
+      if (nb_aps > 1)
+        order_send(aps) ;
+
+      usleep(cfg_getint(cfg, "ap_check_interval")) ;
+    }
+}
+
+
+/*
+ * Deletes APs that did not send any Hello packet for a while, following
+ * the list order. Stops on the first not-to-be-deleted AP.
+ */
+void delete_old_aps()
+{
+  struct timeval now ;
+  gettimeofday(&now, NULL) ;
+
+  while (aps != NULL)
+    if (sub_date(aps->last_seen, now) >
+        (unsigned long) cfg_getint(cfg, "keep_ap_timeout"))
+      delete_ap(aps) ;
+    else
+      return ;
+}
+
+
+/* Deletes an AP from the AP list. */
+inline void delete_ap(ap_list *ap)
+{
+  unlink_ap(ap) ;
+  free(ap) ;
+  --nb_aps ;
+}
+
+
+/* Extracts the given AP from the AP list. */
+void unlink_ap(ap_list *ap)
+{
+  assert(ap) ;
+  ap_list
+    *ap_previous = ap->previous,
+    *ap_next = ap->next ;
+
+  if (ap_previous != NULL)
+    ap_previous->next = ap_next ;
+
+  if (ap_next != NULL)
+    ap_next->previous = ap_previous ;
+
+  if (ap == aps)
+    aps = ap_next ;
+}
+
+
+void order_send(ap_list *ap)
+{
+
+}
+
+
+/* Move the given AP, existing in the AP list, in front of the list. */
+inline void move_ap_front(ap_list *ap)
+{
+  unlink_ap(ap) ;
+  push_ap(ap) ;
+}
+
+
+/* Empty the AP list. */
+void free_ap_list()
+{
+  ap_list *ap_ptr = aps ;
+
+  while (ap_ptr != NULL)
+    {
+      ap_ptr = ap_ptr->next ;
+      free(aps) ;
+      aps = ap_ptr ;
+    }
+}
+
+
+
 #ifdef DEBUG
 /* Prints the couple list */
 void print_couple_list()