From 47b8a9471fe006cef74d1ba8f8a2839fd8164041 Mon Sep 17 00:00:00 2001
From: rodri <rgl@antares-labs.eu>
Date: Sun, 13 Dec 2020 13:49:38 +0000
Subject: initial commit. basic udp echo support.

---
 main.c | 142 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 142 insertions(+)
 create mode 100644 main.c

(limited to 'main.c')

diff --git a/main.c b/main.c
new file mode 100644
index 0000000..8d059e9
--- /dev/null
+++ b/main.c
@@ -0,0 +1,142 @@
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <pthread.h>
+#include <utf.h>
+#include <fmt.h>
+#include "dat.h"
+#include "fns.h"
+#include "args.h"
+
+enum {
+	LPORT = 7
+};
+
+int lfd, ncpu;
+pthread_t *threads;
+pthread_mutex_t attendlock;
+
+int debug;
+char *argv0;
+
+/*
+ * echo service as of rfc862
+ */
+//void
+//srvecho(int fd)
+//{
+//	char buf[8192];
+//	int n;
+//
+//	while((n = read(fd, buf, sizeof buf)) > 0)
+//		if(write(fd, buf, n) != n)
+//			return;
+//}
+//
+//void*
+//tmain(void *a)
+//{
+//	char caddr[128];
+//	int cfd;
+//
+//	for(;;){
+//		pthread_mutex_lock(&attendlock);
+//		if((cfd = acceptcall(lfd, caddr, sizeof caddr)) < 0)
+//			sysfatal("acceptcall: %r");
+//		pthread_mutex_unlock(&attendlock);
+//
+//		if(debug)
+//			fprint(2, "thr#%lu accepted call from %s\n", pthread_self(), caddr);
+//
+//		srvecho(cfd);
+//		close(cfd);
+//
+//		if(debug)
+//			fprint(2, "thr#%lu ended call with %s\n", pthread_self(), caddr);
+//	}
+//}
+
+/*
+ * (udp)echo service as of rfc862
+ */
+void*
+udpechosrv(void *a)
+{
+	sockaddr_in csa;
+	char buf[4096], caddr[128], *cs;
+	int n, port;
+	uint csalen;
+
+	memset(&csa, 0, sizeof(sockaddr_in));
+	csalen = sizeof(sockaddr_in);
+
+	for(;;){
+		pthread_mutex_lock(&attendlock);
+		if((n = recvfrom(lfd, buf, sizeof buf, 0, (sockaddr*)&csa, &csalen)) < 0){
+			pthread_mutex_unlock(&attendlock);
+			continue;
+		}
+		pthread_mutex_unlock(&attendlock);
+
+		cs = inet_ntoa(csa.sin_addr);
+		port = ntohs(csa.sin_port);
+		snprint(caddr, sizeof caddr, "udp!%s!%d", cs, port);
+
+		if(debug)
+			fprint(2, "thr#%lu received %d byte datagram from %s\n", pthread_self(), n, caddr);
+
+		if(sendto(lfd, buf, n, 0, (sockaddr*)&csa, csalen) < 0)
+			continue;
+
+		if(debug)
+			fprint(2, "thr#%lu sent %d byte datagram to %s\n", pthread_self(), n, caddr);
+	}
+}
+
+static void
+usage(void)
+{
+	fprint(2, "usage: %s [-d]\n", argv0);
+	exit(1);
+}
+
+int
+main(int argc, char *argv[])
+{
+	int i;
+
+	ARGBEGIN{
+	case 'd': debug++; break;
+	default: usage();
+	}ARGEND;
+	if(argc != 0)
+		usage();
+
+	if((lfd = bindudp(LPORT)) < 0)
+		sysfatal("bindudp: %r");
+
+	ncpu = sysconf(_SC_NPROCESSORS_ONLN);
+	if(ncpu < 1)
+		ncpu = 1;
+
+	threads = emalloc(sizeof(pthread_t)*ncpu);
+	pthread_mutex_init(&attendlock, nil);
+
+	for(i = 0; i < ncpu; i++){
+		pthread_create(threads+i, nil, udpechosrv, nil);
+		if(debug)
+			fprint(2, "created thr#%lu\n", *(threads+i));
+	}
+
+	pause();
+
+	free(threads);
+	pthread_mutex_destroy(&attendlock);
+	exit(0);
+}
-- 
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