source: npl/overig/netcat_openbsd/patches/0002-connect-timeout.patch @ 8f1e3c5

From: Aron Xu <aron@debian.org>
Date: Mon, 13 Feb 2012 14:43:56 +0800
Subject: connect timeout

---
 netcat.c |   77 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 75 insertions(+), 2 deletions(-)

diff --git a/netcat.c b/netcat.c
index 9b2def2..f3cc8c1 100644
--- a/netcat.c
+++ b/netcat.c
@@ -106,6 +106,10 @@
 #define PORT_MAX_LEN   6
 #define UNIX_DG_TMP_SOCKET_SIZE        19
 
+#define CONNECTION_SUCCESS 0
+#define CONNECTION_FAILED 1
+#define CONNECTION_TIMEOUT 2
+
 /* Command Line Options */
 int    dflag;                                  /* detached, no stdin */
 unsigned int iflag;                            /* Interval Flag */
@@ -151,6 +155,9 @@ void        set_common_sockopts(int);
 int    map_tos(char *, int *);
 void   usage(int);
 
+static int connect_with_timeout(int fd, const struct sockaddr *sa,
+        socklen_t salen, int ctimeout);
+
 int
 main(int argc, char *argv[])
 {
@@ -651,11 +658,14 @@ remote_connect(const char *host, const char *port, struct addrinfo hints)
 
                set_common_sockopts(s);
 
-               if (timeout_connect(s, res0->ai_addr, res0->ai_addrlen) == 0)
+                if ((error = connect_with_timeout(s, res0->ai_addr, res0->ai_addrlen, timeout))== CONNECTION_SUCCESS)
                        break;
-               else if (vflag)
+               else if (vflag && error == CONNECTION_FAILED)
                        warn("connect to %s port %s (%s) failed", host, port,
                            uflag ? "udp" : "tcp");
+                else if (vflag && error == CONNECTION_TIMEOUT)
+                    warn("connect to %s port %s (%s) timed out", host, port,
+                            uflag ? "udp" : "tcp");
 
                close(s);
                s = -1;
@@ -703,6 +713,69 @@ timeout_connect(int s, const struct sockaddr *name, socklen_t namelen)
        return (ret);
 }
 
+static int connect_with_timeout(int fd, const struct sockaddr *sa,
+                               socklen_t salen, int ctimeout)
+{
+       int err;
+       struct timeval tv, *tvp = NULL;
+       fd_set connect_fdset;
+       socklen_t len;
+       int orig_flags;
+
+       orig_flags = fcntl(fd, F_GETFL, 0);
+       if (fcntl(fd, F_SETFL, orig_flags | O_NONBLOCK) < 0 ) {
+               warn("can't set O_NONBLOCK - timeout not available");
+               if (connect(fd, sa, salen) == 0)
+                       return CONNECTION_SUCCESS;
+               else
+                       return CONNECTION_FAILED;
+       }
+
+       /* set connect timeout */
+       if (ctimeout > 0) {
+               tv.tv_sec = (time_t)ctimeout/1000;
+               tv.tv_usec = 0;
+               tvp = &tv;
+       }
+
+       /* attempt the connection */
+       err = connect(fd, sa, salen);
+       if (err != 0 && errno == EINPROGRESS) {
+               /* connection is proceeding
+                * it is complete (or failed) when select returns */
+
+               /* initialize connect_fdset */
+               FD_ZERO(&connect_fdset);
+               FD_SET(fd, &connect_fdset);
+
+               /* call select */
+               do {
+                       err = select(fd + 1, NULL, &connect_fdset,
+                                    NULL, tvp);
+               } while (err < 0 && errno == EINTR);
+
+               /* select error */
+               if (err < 0)
+                       errx(1,"select error: %s", strerror(errno));
+               /* we have reached a timeout */
+               if (err == 0)
+                       return CONNECTION_TIMEOUT;
+               /* select returned successfully, but we must test socket
+                * error for result */
+               len = sizeof(err);
+               if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &len) < 0)
+                       errx(1, "getsockopt error: %s", strerror(errno));
+               /* setup errno according to the result returned by
+                * getsockopt */
+               if (err != 0)
+                       errno = err;
+       }
+
+       /* return aborted if an error occured, and valid otherwise */
+       fcntl(fd, F_SETFL, orig_flags);
+       return (err != 0)? CONNECTION_FAILED : CONNECTION_SUCCESS;
+}
+
 /*
  * local_listen()
  * Returns a socket listening on a local port, binds to specified source
--