@@ -37,13 +37,20 @@ typedef struct urusai {

         client *clients;

 } urusai;

+typedef enum seenaction {

+	seen_error=0,

+	seen_new,

+	seen_updated,

+	seen_nochange

+} seenaction;

+

 static int signal_init(int signum, void (*fn)(int));

 static void sigint(int signum);

 volatile int sigint_flag=0;

 urusai *urusai_init(void);

 void urusai_free(urusai *u);

-client *urusai_clientseen(urusai *u, char *id, struct sockaddr_in *addr);

+client *urusai_clientseen(urusai *u, char *id, struct sockaddr_in *addr, seenaction *seen);

 int urusai_clientdeleteold(urusai *u, int timeout);

 client *urusai_clientget(urusai *u, char *id);

 int urusai_send(urusai *u, char *outbuf, int outbuf_used, client *destclient);

@@ -62,6 +69,7 @@ main(int argc, char *argv[])

         urusai *u;

         client *origclient, *destclient;

         char *serial,*origid,*destid,*cmd,*contents;

+	seenaction seen;	

         if((u=urusai_init())==NULL) {

                 printf("ERROR: Couldn'n get/bind socket or insufficient memory\n");

                 return(1);

@@ -69,15 +77,16 @@ main(int argc, char *argv[])

         sigint_flag=0;

         signal_init(SIGINT,sigint);

         while(!sigint_flag) {

+		memset(&clientaddr,0,sizeof(clientaddr));

                 clientaddr_len=sizeof(clientaddr);

                 if((inbuf_used=recvfrom(u->fd,inbuf,sizeof(inbuf),0,(struct sockaddr *)&clientaddr,&clientaddr_len))==-1)

                         continue; /* interrupted by signal */

                 if(msg_parse(inbuf,inbuf_used,&serial,&origid,&destid,&cmd,&contents)!=0)

                         continue;

-                if((origclient=urusai_clientseen(u,origid,&clientaddr))==NULL)

+                if((origclient=urusai_clientseen(u,origid,&clientaddr,&seen))==NULL)

                         continue;

                 if(strcmp(cmd,"ping")==0) {

-                        outbuf_used=msg_compose(outbuf, sizeof(outbuf), serial, NULL, origid,"pong",NULL);

+                        outbuf_used=msg_compose(outbuf, sizeof(outbuf), serial, NULL, origid,"pong",(seen==seen_new)?"new":(seen==seen_updated)?"updated":(seen==seen_nochange)?"nochange":NULL);

                         urusai_send(u,outbuf,outbuf_used,origclient);

                 } else if(strcmp(cmd,"message")==0) {

                         if((destclient=urusai_clientget(u,destid))==NULL) {

@@ -154,12 +163,15 @@ urusai_free(urusai *u)

 }

 client *

-urusai_clientseen(urusai *u, char *id, struct sockaddr_in *addr)

+urusai_clientseen(urusai *u, char *id, struct sockaddr_in *addr,seenaction *seen)

 {

         int i,ifree;

         client *c;

-        if(u==NULL)

+        if(u==NULL || id==NULL || addr==NULL || seen==NULL) {

+		if(seen!=NULL)

+			*seen=seen_error;

                 return(NULL);

+	}

         if(u->numclients==u->sizeclients) {

                 client *newc;

                 if((newc=realloc(u->clients,sizeof(client)*(u->sizeclients+CLIENTBLOCK)))==NULL)

@@ -176,13 +188,21 @@ urusai_clientseen(urusai *u, char *id, struct sockaddr_in *addr)

                         break;

         }

         if(i==u->sizeclients) {

-                if(ifree==-1)

+                if(ifree==-1) {

+			*seen=seen_error;

                         return(NULL);

+		}

                 i=ifree;

                 c=u->clients+i;

                 strncpy(c->id,id,sizeof(c->id));

                 c->id[sizeof(c->id)-1]='\0';

-        }

+		*seen=seen_new;

+        } else {

+		if(memcmp(&(c->addr),addr,sizeof(c->addr))==0)

+			*seen=seen_nochange;

+		else

+			*seen=seen_updated;

+	}

         c->lastrecv=time(NULL);

         memcpy(&(c->addr),addr,sizeof(c->addr));

         return(c);