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-rw-r--r--toys/netcat.c116
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);
+}