Dear all,
Scratching a small itch: telnet(1) nicely prints what IP addresses it is
attempting to connect to, I'd like 'nc -v' to do the same, see below:
$ nc -v localhost 23
nc: connect to localhost (127.0.0.1) port 23 (tcp) failed: Connection refused
nc: connect to localhost (::1) port 23 (tcp) failed: Connection refused
$ # dont bother printing IPs when -n or host == ipaddr
$ nc -v -n 127.0.0.1 23
nc: connect to 127.0.0.1 port 23 (tcp) failed: Connection refused
$ dig a www.peeringdb.com +short
54.209.79.173
3.221.183.110
$ nc -v www.peeringdb.com 80
Connection to www.peeringdb.com (54.209.79.173) 80 port [tcp/www] succeeded!
^C
OK?
Kind regards,
Job
Index: netcat.c
===================================================================
RCS file: /cvs/src/usr.bin/nc/netcat.c,v
retrieving revision 1.207
diff -u -p -r1.207 netcat.c
--- netcat.c 17 Oct 2019 14:29:24 -0000 1.207
+++ netcat.c 23 Oct 2019 20:55:21 -0000
@@ -125,7 +125,7 @@ void help(void) __attribute__((noreturn)
int local_listen(const char *, const char *, struct addrinfo);
void readwrite(int, struct tls *);
void fdpass(int nfd) __attribute__((noreturn));
-int remote_connect(const char *, const char *, struct addrinfo);
+int remote_connect(const char *, const char *, struct addrinfo, char *);
int timeout_tls(int, struct tls *, int (*)(struct tls *));
int timeout_connect(int, const struct sockaddr *, socklen_t);
int socks_connect(const char *, const char *, struct addrinfo,
@@ -151,6 +151,7 @@ main(int argc, char *argv[])
{
int ch, s = -1, ret, socksv;
char *host, *uport;
+ char ipaddr[NI_MAXHOST];
struct addrinfo hints;
struct servent *sv;
socklen_t len;
@@ -677,7 +678,8 @@ main(int argc, char *argv[])
proxy, proxyport, proxyhints, socksv,
Pflag);
else
- s = remote_connect(host, portlist[i], hints);
+ s = remote_connect(host, portlist[i], hints,
+ ipaddr);
if (s == -1)
continue;
@@ -701,10 +703,14 @@ main(int argc, char *argv[])
uflag ? "udp" : "tcp");
}
- fprintf(stderr,
- "Connection to %s %s port [%s/%s] "
- "succeeded!\n", host, portlist[i],
- uflag ? "udp" : "tcp",
+ fprintf(stderr, "Connection to %s", host);
+
+ /* if there is something to report, print IP */
+ if (!nflag && (strcmp(host, ipaddr) != 0))
+ fprintf(stderr, " (%s)", ipaddr);
+
+ fprintf(stderr, " %s port [%s/%s] succeeded!\n",
+ portlist[i], uflag ? "udp" : "tcp",
sv ? sv->s_name : "*");
}
if (Fflag)
@@ -916,10 +922,11 @@ unix_listen(char *path)
* port or source address if needed. Returns -1 on failure.
*/
int
-remote_connect(const char *host, const char *port, struct addrinfo hints)
+remote_connect(const char *host, const char *port, struct addrinfo hints,
+ char *ipaddr)
{
struct addrinfo *res, *res0;
- int s = -1, error, on = 1, save_errno;
+ int s = -1, error, herr, on = 1, save_errno;
if ((error = getaddrinfo(host, port, &hints, &res0)))
errx(1, "getaddrinfo for host \"%s\" port %s: %s", host,
@@ -952,11 +959,26 @@ remote_connect(const char *host, const c
set_common_sockopts(s, res->ai_family);
+ if ((herr = getnameinfo(res->ai_addr, res->ai_addrlen, ipaddr,
+ NI_MAXHOST, NULL, 0, NI_NUMERICHOST)) != 0) {
+ if (herr == EAI_SYSTEM)
+ err(1, "getnameinfo");
+ else
+ errx(1, "getnameinfo: %s", gai_strerror(herr));
+ }
+
if (timeout_connect(s, res->ai_addr, res->ai_addrlen) == 0)
break;
- if (vflag)
- warn("connect to %s port %s (%s) failed", host, port,
- uflag ? "udp" : "tcp");
+
+ if (vflag) {
+ /* only print IP if there is something to report */
+ if (nflag || (strncmp(host, ipaddr, NI_MAXHOST) == 0))
+ warn("connect to %s port %s (%s) failed", host,
+ port, uflag ? "udp" : "tcp");
+ else
+ warn("connect to %s (%s) port %s (%s) failed",
+ host, ipaddr, port, uflag ? "udp" : "tcp");
+ }
save_errno = errno;
close(s);
