Add first pass at netcat. Base applet, -f, and -w implemented.

1 files changed, 116 insertions, 0 deletions

diff --git a/toys/netcat.c b/toys/netcat.c
new file mode 100644
index 00000000..39c531d8
--- /dev/null
+++ b/toys/netcat.c
@@ -0,0 +1,116 @@
+/* vi: set sw=4 ts=4: */
+/* nc: mini-netcat - Forward stdin/stdout to a file or network connection.
+ *
+ * Copyright 2007 Rob Landley <rob@landley.net>
+ */
+
+#include "toys.h"
+#include "toynet.h"
+
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#define TT toy.netcat
+
+static void timeout(int signum)
+{
+	error_exit("Timeout");
+}
+
+// Translate x.x.x.x numeric IPv4 address, or else DNS lookup an IPv4 name.
+void lookup_name(char *name, uint32_t *result)
+{
+	struct hostent *hostbyname;
+
+	hostbyname = gethostbyname(*toys.optargs);
+	if (!hostbyname) error_exit("name lookup failed");
+	*result = *(uint32_t *)*hostbyname->h_addr_list;
+}
+
+// Worry about a fancy lookup later.
+void lookup_port(char *str, uint16_t *port)
+{
+  *port = SWAP_BE16(atoi(str));
+}
+
+void netcat_main(void)
+{
+	int sockfd, pollcount;
+	struct pollfd pollfds[2];
+
+	if (TT.wait) {
+		signal(SIGALRM, timeout);
+		alarm(TT.wait);
+	}
+
+	if (TT.filename) pollfds[0].fd = xopen(TT.filename, O_RDWR);
+	else {
+		int temp;
+		struct sockaddr_in address;
+
+		// The argument parsing logic can't make "<2" conditional on "-f", so...
+		if (!*toys.optargs || !toys.optargs[1]) {
+			toys.exithelp++;
+			error_exit("Need address and port");
+		}
+
+		// Setup socket
+		sockfd = socket(AF_INET, SOCK_STREAM, 0);
+		if (-1 == sockfd) perror_exit("socket");
+		fcntl(sockfd, F_SETFD, FD_CLOEXEC);
+		temp = 1;
+		setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &temp, sizeof(temp));
+		memset(&address, 0, sizeof(address));
+		address.sin_family = AF_INET;
+		if (TT.port) {
+			address.sin_port = TT.port;
+			if (-1 == bind(sockfd, &address, sizeof(address)))
+				perror_exit("bind");
+		}
+
+		// Figure out where to dial out to.
+		lookup_name(*toys.optargs, (uint32_t *)&address.sin_addr);
+		lookup_port(toys.optargs[1], &address.sin_port);
+		temp = connect(sockfd, (struct sockaddr *)&address, sizeof(address));
+		if (temp<0) perror_exit("connect");
+		pollfds[0].fd = sockfd;
+	}
+
+	// We have a connection.  Disarm timeout.
+	if (TT.wait) {
+		alarm(0);
+		signal(SIGALRM, SIG_DFL);
+	}
+
+	pollcount = 2;
+	pollfds[1].fd = 0;
+	pollfds[0].events = pollfds[1].events = POLLIN;
+
+	// Poll loop copying stdin->socket and socket->stdout.
+	for (;;) {
+		int i;
+
+		if (0>poll(pollfds, pollcount, -1)) perror_exit("poll");
+
+		for (i=0; i<pollcount; i++) {
+			if (pollfds[i].revents & POLLIN) {
+				int len = read(pollfds[i].fd, toybuf, sizeof(toybuf));
+				if (len<1) goto dohupnow;
+				xwrite(i ? pollfds[0].fd : 1, toybuf, len);
+			}
+			if (pollfds[i].revents & POLLHUP) {
+dohupnow:
+				// Close half-connect.  This is needed for things like
+				// "echo GET / | netcat landley.net 80" to work.
+				if (i) {
+					shutdown(pollfds[0].fd, SHUT_WR);
+					pollcount--;
+				} else goto cleanup;
+			}
+		}
+	}
+cleanup:
+	close(pollfds[0].fd);
+//	close(sockfd);
+}