Respond pings with pongs.

Set the state of a friend as offline if timeout goes without receiving
PONG. If PING is received, send PONG. If PONG is received, set state as
online.

diff --git a/friend.c b/friend.c
index 68deccd..03d306d 100644 (file)
--- a/friend.c
+++ b/friend.c
@@ -27,11 +27,18 @@
 #include <stdio.h>
 #include "message.h"
 
+enum {
+       STATE_OFFLINE,
+       STATE_PINGED,
+       STATE_ONLINE,
+};
+
 struct friend {
        char *name;
        char *address;
        uint16_t port;
        GInetSocketAddress *saddr;
+       int state;
 };
 
 static GSocket *usock;
@@ -64,6 +71,22 @@ int friend_send_message(struct friend *friend, char *buffer, size_t len)
        return 0;
 }
 
+void friend_timeout(struct friend *friend)
+{
+       if (friend->state == STATE_PINGED) {
+               friend->state = STATE_OFFLINE;
+       }
+}
+
+void friend_got_message(struct friend *friend, char *buffer, size_t len)
+{
+       if (len >= 4 && !strncmp(buffer, "PING", 4)) {
+               pong(friend);
+       } else if (len >= 4 && !strncmp(buffer, "PONG", 4)) {
+               friend->state = STATE_ONLINE;
+       }
+}
+
 struct cache {
        GList *friends;
 };
@@ -123,6 +146,7 @@ int cache_add_friend(struct cache *cache, char *name, char *address, uint16_t po
        g_object_unref(addr);
        cache->friends = g_list_append(cache->friends, friend);
        ping(friend);
+       friend->state = STATE_PINGED;
        return 0;
 }
 

diff --git a/friend.h b/friend.h
index 76a22bd..efe5f65 100644 (file)
--- a/friend.h
+++ b/friend.h
@@ -38,4 +38,7 @@ struct friend *friend_get_by_address(GInetAddress *address, uint16_t port);
 
 char *friend_get_name();
 
+void friend_timeout(struct friend *friend);
+void friend_got_message(struct friend *friend, char *buffer, size_t len);
+
 #endif

diff --git a/message.c b/message.c
index 25b5160..8c6dafd 100644 (file)
--- a/message.c
+++ b/message.c
@@ -26,6 +26,7 @@
 gboolean ping_timeout(gpointer data)
 {
        struct friend *friend = data;
+       friend_timeout(friend);
        return G_SOURCE_REMOVE;
 }
 
@@ -58,7 +59,7 @@ gboolean message_incoming(GIOChannel *channel, GIOCondition cond, gpointer data)
                friend = friend_get_by_address(iaddress, port);
                if (friend) {
                        printf("got message from %s\n", friend_get_name(friend));
-                       g_source_remove_by_user_data(friend);
+                       friend_got_message(friend, buffer, len);
                } else {
                        printf("could not find friend from address %s\n", g_inet_address_to_string(iaddress));
                }
@@ -77,7 +78,16 @@ int message_init(GSocket *sock)
 
 int ping(struct friend *friend)
 {
+       int err;
        char ping[5] = "PING";
-       friend_send_message(friend, ping, 4);
-       g_timeout_add(2000, ping_timeout, friend);
+       err = friend_send_message(friend, ping, 4);
+       if (!err)
+               g_timeout_add(2000, ping_timeout, friend);
+       return err;
+}
+
+int pong(struct friend *friend)
+{
+       char pong[5] = "PONG";
+       return friend_send_message(friend, pong, 4);
 }

diff --git a/message.h b/message.h
index d2fbcc1..cd018c9 100644 (file)
--- a/message.h
+++ b/message.h
@@ -24,5 +24,6 @@
 
 int message_init(GSocket *sock);
 int ping(struct friend *friend);
+int pong(struct friend *friend);
 
 #endif