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.

---
 util.c | 113 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 113 insertions(+)
 create mode 100644 util.c

(limited to 'util.c')

diff --git a/util.c b/util.c
new file mode 100644
index 0000000..26acbc3
--- /dev/null
+++ b/util.c
@@ -0,0 +1,113 @@
+#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 <utf.h>
+#include <fmt.h>
+#include "dat.h"
+#include "fns.h"
+
+extern int debug;
+
+void
+sysfatal(char *fmt, ...)
+{
+	va_list arg;
+	char buf[2048];
+
+	va_start(arg, fmt);
+	vseprint(buf, buf+sizeof(buf), fmt, arg);
+	va_end(arg);
+	fprint(2, "%s\n", buf);
+	exit(1);
+}
+
+void *
+emalloc(ulong n)
+{
+	void *p;
+
+	p = malloc(n);
+	if(p == nil)
+		sysfatal("malloc: %r");
+	memset(p, 0, n);
+	return p;
+}
+
+sockaddr_in*
+mkinetsa(char *ipaddr, int port)
+{
+	sockaddr_in *sa;
+
+	sa = emalloc(sizeof(sockaddr_in));
+	sa->sin_family = AF_INET;
+	if(inet_pton(AF_INET, ipaddr, &sa->sin_addr.s_addr) <= 0)
+		sysfatal("inet_pton: %r");
+	sa->sin_port = htons(port);
+	return sa;
+}
+
+int
+listentcp(int port)
+{
+	sockaddr_in *addr;
+	int fd;
+
+	addr = mkinetsa("0.0.0.0", port);
+	if((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0)
+		return -1;
+	if(bind(fd, (sockaddr*)addr, sizeof(sockaddr_in)) < 0){
+		close(fd);
+		return -1;
+	}
+	if(listen(fd, 128) < 0){
+		close(fd);
+		return -1;
+	}
+	if(debug)
+		fprint(2, "listening on tcp!%s!%d\n", inet_ntoa(addr->sin_addr), port);
+	free(addr);
+	return fd;
+}
+
+int
+bindudp(int port)
+{
+	sockaddr_in *addr;
+	int fd;
+
+	addr = mkinetsa("0.0.0.0", port);
+	if((fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0)
+		return -1;
+	if(bind(fd, (sockaddr*)addr, sizeof(sockaddr_in)) < 0){
+		close(fd);
+		return -1;
+	}
+	if(debug)
+		fprint(2, "listening on udp!%s!%d\n", inet_ntoa(addr->sin_addr), port);
+	free(addr);
+	return fd;
+}
+
+int
+acceptcall(int lfd, char *caddr, int caddrlen)
+{
+	sockaddr_in addr;
+	uint addrlen;
+	int fd, port;
+	char *cs;
+
+	memset(&addr, 0, sizeof(sockaddr_in));
+	addrlen = sizeof(sockaddr_in);
+	if((fd = accept(lfd, (sockaddr*)&addr, &addrlen)) < 0)
+		return -1;
+	cs = inet_ntoa(addr.sin_addr);
+	port = ntohs(addr.sin_port);
+	snprint(caddr, caddrlen, "tcp!%s!%d", cs, port);
+	return fd;
+}
-- 
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