source: npl/overig/netcat_openbsd/patches/0007-udp-scan-timeout.patch @ 2154c77

From: Aron Xu <aron@debian.org>
Date: Mon, 13 Feb 2012 15:29:37 +0800
Subject: udp scan timeout

---
 netcat.c |   25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/netcat.c b/netcat.c
index 29ecf1a..baab909 100644
--- a/netcat.c
+++ b/netcat.c
@@ -111,6 +111,8 @@
 #define CONNECTION_FAILED 1
 #define CONNECTION_TIMEOUT 2
 
+#define UDP_SCAN_TIMEOUT 3                     /* Seconds */
+
 /* Command Line Options */
 int     Cflag = 0;                              /* CRLF line-ending */
 int    dflag;                                  /* detached, no stdin */
@@ -497,7 +499,7 @@ 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) {
@@ -1057,15 +1059,20 @@ build_ports(char *p)
 int
 udptest(int s)
 {
-       int i, ret;
-
-       for (i = 0; i <= 3; i++) {
-               if (write(s, "X", 1) == 1)
-                       ret = 1;
-               else
-                       ret = -1;
+       int i, t;
+
+       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
--