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From: Aron Xu <aron@debian.org>
Date: Mon, 13 Feb 2012 14:43:56 +0800
Subject: Fix connect() timeout
---
netcat.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 77 insertions(+), 5 deletions(-)
diff --git a/netcat.c b/netcat.c
index bec6e46..461e2bd 100644
--- a/netcat.c
+++ b/netcat.c
@@ -90,6 +90,7 @@
#include <ctype.h>
#include <err.h>
#include <errno.h>
+#include <fcntl.h>
#include <limits.h>
#include <netdb.h>
#include <poll.h>
@@ -124,6 +125,10 @@
# define TLS_MUSTSTAPLE (1 << 4)
#endif
+#define CONNECTION_SUCCESS 0
+#define CONNECTION_FAILED 1
+#define CONNECTION_TIMEOUT 2
+
/* Command Line Options */
int dflag; /* detached, no stdin */
int Fflag; /* fdpass sock to stdout */
@@ -215,6 +220,8 @@ ssize_t drainbuf(int, unsigned char *, size_t *);
ssize_t fillbuf(int, unsigned char *, size_t *);
#endif
+static int connect_with_timeout(int, const struct sockaddr *, socklen_t, int);
+
int
main(int argc, char *argv[])
{
@@ -1088,18 +1095,21 @@ remote_connect(const char *host, const char *port, struct addrinfo hints,
}
}
- if (timeout_connect(s, res->ai_addr, res->ai_addrlen) == 0)
+ if ((error = connect_with_timeout(s, res->ai_addr, res->ai_addrlen,
+ timeout)) == CONNECTION_SUCCESS)
break;
if (vflag) {
/* only print IP if there is something to report */
if (nflag || ipaddr == NULL ||
(strncmp(host, ipaddr, NI_MAXHOST) == 0))
- warn("connect to %s port %s (%s) failed", host,
- port, uflag ? "udp" : "tcp");
+ warn("connect to %s port %s (%s) %s", host,
+ port, uflag ? "udp" : "tcp",
+ error == CONNECTION_TIMEOUT ? "timed out" : "failed");
else
- warn("connect to %s (%s) port %s (%s) failed",
- host, ipaddr, port, uflag ? "udp" : "tcp");
+ warn("connect to %s (%s) port %s (%s) %s",
+ host, ipaddr, port, uflag ? "udp" : "tcp",
+ error == CONNECTION_TIMEOUT ? "timed out" : "failed");
}
save_errno = errno;
@@ -1141,6 +1151,68 @@ 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
|
