Add listening support.

5 files changed, 102 insertions, 29 deletions

diff --git a/applets/usage.c b/applets/usage.c
index 215871b5a..1686910d5 100644
--- a/applets/usage.c
+++ b/applets/usage.c
@@ -959,9 +959,13 @@ const char mv_usage[] =
 
 #if defined BB_NC
 const char nc_usage[] =
-        "nc [IP] [port]" 
+        "nc [-p PORT] IP PORT\n"
+        "   or: nc -l -p PORT"
 #ifndef BB_FEATURE_TRIVIAL_HELP
-        "\n\nNetcat opens a pipe to IP:port"
+        "\n\nNetcat opens a pipe to IP:PORT\n"
+        "Options:\n"
+        "\t-l\tListen on the socket.\n"
+        "\t-p PORT\tBind the local port to PORT."
 #endif
         ;
 #endif
diff --git a/docs/busybox.sgml b/docs/busybox.sgml
index 0dc4bffa3..02d85e499 100644
--- a/docs/busybox.sgml
+++ b/docs/busybox.sgml
@@ -2452,7 +2452,12 @@
                 </para>
 
                 <para>
-                Open a pipe to HOST:PORT.
+                   or: nc -p PORT -l
+                </para>
+
+
+                <para>
+                Open a pipe to HOST:PORT or listen for a connection on PORT.
                 </para>
 
                 <para>
diff --git a/nc.c b/nc.c
index 682da82bf..3f512d1cb 100644
--- a/nc.c
+++ b/nc.c
@@ -41,7 +41,7 @@
 
 int nc_main(int argc, char **argv)
 {
-        int sfd;
+        int do_listen = 0, lport = 0, tmpfd, opt, sfd;
         char buf[BUFSIZ];
 
         struct sockaddr_in address;
@@ -49,24 +49,54 @@ int nc_main(int argc, char **argv)
 
         fd_set readfds, testfds;
 
-        argc--;
-        argv++;
-        if (argc < 2 || **argv == '-') {
-                usage(nc_usage);
+        while ((opt = getopt(argc, argv, "lp:")) > 0) {
+                switch (opt) {
+                        case 'l':
+                                do_listen++;
+                                break;
+                        case 'p':
+                                lport = atoi(optarg);
+                                break;
+                        default:
+                                usage(nc_usage);
+                }
         }
 
+        if ((do_listen && optind != argc) || (!do_listen && optind + 2 != argc))
+                usage(nc_usage);
+
         if ((sfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
                 perror_msg_and_die("socket");
 
-        if ((hostinfo = gethostbyname(*argv)) == NULL)
-                error_msg_and_die("cannot resolve %s", *argv);
-
         address.sin_family = AF_INET;
-        address.sin_addr = *(struct in_addr *) *hostinfo->h_addr_list;
-        address.sin_port = htons(atoi(*(++argv)));
 
-        if (connect(sfd, (struct sockaddr *) &address, sizeof(address)) < 0)
-                perror_msg_and_die("connect");
+        if (lport != 0) {
+                memset(&address.sin_addr, 0, sizeof(address.sin_addr));
+                address.sin_port = htons(lport);
+
+                if (bind(sfd, (struct sockaddr *) &address, sizeof(address)) < 0)
+                        perror_msg_and_die("bind");
+        }
+
+        if (do_listen) {
+                if (listen(sfd, 1) < 0)
+                        perror_msg_and_die("listen");
+
+                if ((tmpfd = accept(sfd, (struct sockaddr *) &address, &opt)) < 0)
+                        perror_msg_and_die("accept");
+
+                close(sfd);
+                sfd = tmpfd;
+        } else {
+                if ((hostinfo = gethostbyname(argv[optind])) == NULL)
+                        error_msg_and_die("cannot resolve %s\n", argv[optind]);
+
+                address.sin_addr = *(struct in_addr *) *hostinfo->h_addr_list;
+                address.sin_port = htons(atoi(argv[optind+1]));
+
+                if (connect(sfd, (struct sockaddr *) &address, sizeof(address)) < 0)
+                        perror_msg_and_die("connect");
+        }
 
         FD_ZERO(&readfds);
         FD_SET(sfd, &readfds);
diff --git a/networking/nc.c b/networking/nc.c
index 682da82bf..3f512d1cb 100644
--- a/networking/nc.c
+++ b/networking/nc.c
@@ -41,7 +41,7 @@
 
 int nc_main(int argc, char **argv)
 {
-        int sfd;
+        int do_listen = 0, lport = 0, tmpfd, opt, sfd;
         char buf[BUFSIZ];
 
         struct sockaddr_in address;
@@ -49,24 +49,54 @@ int nc_main(int argc, char **argv)
 
         fd_set readfds, testfds;
 
-        argc--;
-        argv++;
-        if (argc < 2 || **argv == '-') {
-                usage(nc_usage);
+        while ((opt = getopt(argc, argv, "lp:")) > 0) {
+                switch (opt) {
+                        case 'l':
+                                do_listen++;
+                                break;
+                        case 'p':
+                                lport = atoi(optarg);
+                                break;
+                        default:
+                                usage(nc_usage);
+                }
         }
 
+        if ((do_listen && optind != argc) || (!do_listen && optind + 2 != argc))
+                usage(nc_usage);
+
         if ((sfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
                 perror_msg_and_die("socket");
 
-        if ((hostinfo = gethostbyname(*argv)) == NULL)
-                error_msg_and_die("cannot resolve %s", *argv);
-
         address.sin_family = AF_INET;
-        address.sin_addr = *(struct in_addr *) *hostinfo->h_addr_list;
-        address.sin_port = htons(atoi(*(++argv)));
 
-        if (connect(sfd, (struct sockaddr *) &address, sizeof(address)) < 0)
-                perror_msg_and_die("connect");
+        if (lport != 0) {
+                memset(&address.sin_addr, 0, sizeof(address.sin_addr));
+                address.sin_port = htons(lport);
+
+                if (bind(sfd, (struct sockaddr *) &address, sizeof(address)) < 0)
+                        perror_msg_and_die("bind");
+        }
+
+        if (do_listen) {
+                if (listen(sfd, 1) < 0)
+                        perror_msg_and_die("listen");
+
+                if ((tmpfd = accept(sfd, (struct sockaddr *) &address, &opt)) < 0)
+                        perror_msg_and_die("accept");
+
+                close(sfd);
+                sfd = tmpfd;
+        } else {
+                if ((hostinfo = gethostbyname(argv[optind])) == NULL)
+                        error_msg_and_die("cannot resolve %s\n", argv[optind]);
+
+                address.sin_addr = *(struct in_addr *) *hostinfo->h_addr_list;
+                address.sin_port = htons(atoi(argv[optind+1]));
+
+                if (connect(sfd, (struct sockaddr *) &address, sizeof(address)) < 0)
+                        perror_msg_and_die("connect");
+        }
 
         FD_ZERO(&readfds);
         FD_SET(sfd, &readfds);
diff --git a/usage.c b/usage.c
index 215871b5a..1686910d5 100644
--- a/usage.c
+++ b/usage.c
@@ -959,9 +959,13 @@ const char mv_usage[] =
 
 #if defined BB_NC
 const char nc_usage[] =
-        "nc [IP] [port]" 
+        "nc [-p PORT] IP PORT\n"
+        "   or: nc -l -p PORT"
 #ifndef BB_FEATURE_TRIVIAL_HELP
-        "\n\nNetcat opens a pipe to IP:port"
+        "\n\nNetcat opens a pipe to IP:PORT\n"
+        "Options:\n"
+        "\t-l\tListen on the socket.\n"
+        "\t-p PORT\tBind the local port to PORT."
 #endif
         ;
 #endif