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From: Aron Xu <aron@debian.org>
Date: Mon, 13 Feb 2012 15:29:37 +0800
Subject: udp scan timeout
---
netcat.c | 23 +++++++++++++++--------
1 file changed, 15 insertions(+), 8 deletions(-)
--- a/netcat.c
+++ b/netcat.c
@@ -129,6 +129,8 @@
#define CONNECTION_FAILED 1
#define CONNECTION_TIMEOUT 2
+#define UDP_SCAN_TIMEOUT 3 /* Seconds */
+
/* Command Line Options */
int dflag; /* detached, no stdin */
int Fflag; /* fdpass sock to stdout */
@@ -823,7 +825,7 @@ main(int argc, char *argv[])
continue;
ret = 0;
- if (vflag || zflag) {
+ if (vflag) {
/* For UDP, make sure we are connected. */
if (uflag) {
if (udptest(s) == -1) {
@@ -1768,15 +1770,20 @@ build_ports(char *p)
int
udptest(int s)
{
- int i, ret;
+ int i, t;
- for (i = 0; i <= 3; i++) {
- if (write(s, "X", 1) == 1)
- ret = 1;
- else
- ret = -1;
+ if ((write(s, "X", 1) != 1) ||
+ ((write(s, "X", 1) != 1) && (errno == ECONNREFUSED)))
+ return -1;
+
+ /* Give the remote host some time to reply. */
+ for (i = 0, t = (timeout == -1) ? UDP_SCAN_TIMEOUT : (timeout / 1000);
+ i < t; i++) {
+ sleep(1);
+ if ((write(s, "X", 1) != 1) && (errno == ECONNREFUSED))
+ return -1;
}
- return ret;
+ return 1;
}
void
|
