/*
* urusaiserver.c
*
* UDP notificator server implementing simple messaging.
*
* Author: Dario Rodriguez dario@softhome.net
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <signal.h>
#include <time.h>
#include <errno.h>
#define SERVERPORT 20245
#define BUFLEN 2048
#define MAXID 32
#define CLIENTBLOCK 128
#define MAXPACKETSIZE 1300
typedef struct client {
struct sockaddr_in addr;
time_t lastrecv;
char id[MAXID];
} client;
typedef struct urusai {
int fd;
struct sockaddr_in myaddr;
int numclients;
int sizeclients;
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, 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);
int msg_parse(char *inbuf, int inbuf_used,char **serial,char **origid,char **destid,char **cmd, char **contents);
int msg_compose(char *outbuf, int bufsize, char *serial, char *origid, char *destid, char *cmd, char *contents);
int
main(int argc, char *argv[])
{
char inbuf[BUFLEN],outbuf[BUFLEN];;
int inbuf_used,outbuf_used;
struct sockaddr_in clientaddr;
socklen_t clientaddr_len;
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);
}
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,&seen))==NULL)
continue;
if(strcmp(cmd,"ping")==0) {
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) {
outbuf_used=msg_compose(outbuf, sizeof(outbuf), serial, NULL, origid,"messageerror","destid_unknown");
urusai_send(u,outbuf,outbuf_used,origclient);
} else {
outbuf_used=msg_compose(outbuf, sizeof(outbuf), serial, origid, destid,"message",contents);
urusai_send(u,outbuf,outbuf_used,destclient);
}
} else if(strcmp(cmd,"receipt")==0) {
if((destclient=urusai_clientget(u,destid))==NULL) {
outbuf_used=msg_compose(outbuf, sizeof(outbuf), serial, NULL, origid,"receipterror","destid_unknown");
urusai_send(u,outbuf,outbuf_used,origclient);
} else {
outbuf_used=msg_compose(outbuf, sizeof(outbuf), serial, origid, destid,"receipt",contents);
urusai_send(u,outbuf,outbuf_used,destclient);
}
}
}
urusai_free(u),u=NULL;
return(0);
}
static int
signal_init(int signum, void (*fn)(int))
{
struct sigaction sa;
sa.sa_handler=fn;
sigemptyset(&sa.sa_mask);
sa.sa_flags=0;
return(sigaction(signum,&sa,0));
}
static void
sigint(int signum)
{
sigint_flag=1;
}
urusai *
urusai_init(void)
{
urusai *u;
if((u=malloc(sizeof(urusai)))==NULL)
return(NULL);
memset(u,0,sizeof(urusai));
if((u->fd=socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP))==-1) {
urusai_free(u),u=NULL;
return(NULL);
}
u->myaddr.sin_family=AF_INET;
u->myaddr.sin_port=htons(SERVERPORT);
u->myaddr.sin_addr.s_addr=htonl(INADDR_ANY);
if(bind(u->fd,(struct sockaddr *)&(u->myaddr),sizeof(u->myaddr))==-1) {
urusai_free(u),u=NULL;
return(NULL);
}
return(u);
}
void
urusai_free(urusai *u)
{
if(u==NULL)
return;
if(u->fd!=-1)
close(u->fd),u->fd=-1;
if(u->clients) {
free(u->clients),u->clients=NULL;
u->numclients=0;
u->sizeclients=0;
}
free(u),u=NULL;
}
client *
urusai_clientseen(urusai *u, char *id, struct sockaddr_in *addr,seenaction *seen)
{
int i,ifree;
client *c;
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)
return(NULL);
u->clients=newc;
memset(u->clients+u->sizeclients,0,CLIENTBLOCK*sizeof(client));
u->sizeclients+=CLIENTBLOCK;
}
for(i=0,ifree=-1;i<u->sizeclients;i++) {
c=u->clients+i;
if(c->id[0]=='\0' && ifree==-1)
ifree=i;
if(strcmp(id,c->id)==0)
break;
}
if(i==u->sizeclients) {
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);
}
int
urusai_clientdeleteold(urusai *u, int timeout)
{
time_t cuttime;
int i;
client *c;
if(u==NULL)
return(-1);
cuttime=time(NULL)-timeout;
for(i=0;i<u->sizeclients;i++) {
c=u->clients+i;
if(c->id[0]=='\0' || c->lastrecv>cuttime)
continue;
memset(c,0,sizeof(client));
}
return(0);
}
client *
urusai_clientget(urusai *u, char *id)
{
int i;
client *c;
if(u==NULL || id[0]=='\0')
return(NULL);
for(i=0;i<u->sizeclients;i++) {
c=u->clients+i;
if(strcmp(id,c->id)==0)
return(c);
}
return(NULL);
}
int
urusai_send(urusai *u, char *outbuf, int outbuf_used, client *destclient)
{
struct sockaddr_in to;
if(u==NULL || outbuf==NULL || outbuf_used<=0 || destclient==NULL)
return(-1);
memcpy(&to,&(destclient->addr),sizeof(to));
if(sendto(u->fd,outbuf,outbuf_used,0,(struct sockaddr *)&to,sizeof(to))==-1)
return(-1);
return(0);
}
int
msg_parse(char *inbuf, int inbuf_used,char **serial,char **origid,char **destid,char **cmd, char **contents)
{
char *ptr;
if(inbuf==NULL || inbuf_used<=0)
return(-1);
*serial=inbuf;
if((ptr=memchr(*serial,0,inbuf_used-(*serial-inbuf)))==NULL)
return(-1);
*origid=ptr+1;
if((ptr=memchr(*origid,0,inbuf_used-(*origid-inbuf)))==NULL)
return(-1);
*destid=ptr+1;
if((ptr=memchr(*destid,0,inbuf_used-(*destid-inbuf)))==NULL)
return(-1);
*cmd=ptr+1;
if((ptr=memchr(*cmd,0,inbuf_used-(*cmd-inbuf)))==NULL)
return(-1);
*contents=ptr+1;
if((ptr=memchr(*contents,0,inbuf_used-(*contents-inbuf)))==NULL)
return(-1);
return(0);
}
int msg_compose(char *outbuf, int bufsize, char *serial, char *origid, char *destid, char *cmd, char *contents)
{
int totallen,len;
char *ptr;
if(outbuf==NULL || bufsize<=0 || serial==NULL)
return(-1);
totallen=strlen(serial)+1+
((origid==NULL)?0:strlen(origid))+1+
((destid==NULL)?0:strlen(destid))+1+
((cmd==NULL)?0:strlen(cmd))+1+
((contents==NULL)?0:strlen(contents))+1;
if(totallen>bufsize || totallen>MAXPACKETSIZE)
return(-1);
ptr=outbuf;
len=strlen(serial);
memcpy(ptr,serial,len),ptr+=len;
*(ptr++)=0;
len=(origid==NULL)?0:strlen(origid);
memcpy(ptr,origid,len),ptr+=len;
*(ptr++)=0;
len=(destid==NULL)?0:strlen(destid);
memcpy(ptr,destid,len),ptr+=len;
*(ptr++)=0;
len=(cmd==NULL)?0:strlen(cmd);
memcpy(ptr,cmd,len),ptr+=len;
*(ptr++)=0;
len=(contents==NULL)?0:strlen(contents);
memcpy(ptr,contents,len),ptr+=len;
*(ptr++)=0;
return(ptr-outbuf);
}