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-rw-r--r--toys/netcat.c188
1 files changed, 140 insertions, 48 deletions
diff --git a/toys/netcat.c b/toys/netcat.c
index f5024c9b..9e27669c 100644
--- a/toys/netcat.c
+++ b/toys/netcat.c
@@ -6,28 +6,40 @@
*
* Not in SUSv3.
-USE_NETCAT(OLDTOY(nc, netcat, "i#w#l@p#s:q#f:e", TOYFLAG_BIN))
-USE_NETCAT(NEWTOY(netcat, "i#w#l@p#s:q#f:e", TOYFLAG_BIN))
+USE_NETCAT(OLDTOY(nc, netcat, USE_NETCAT_LISTEN("tl^L^")"w#p#s:q#f:", TOYFLAG_BIN))
+USE_NETCAT(NEWTOY(netcat, USE_NETCAT_LISTEN("tl^L^")"w#p#s:q#f:", TOYFLAG_BIN))
config NETCAT
bool "netcat"
- default n
+ default y
help
- usage: netcat [-iwlp] {IPADDR PORTNUM|-f FILENAME} [-e COMMAND]
+ usage: netcat [-wpq #] [-s addr] {IPADDR PORTNUM|-f FILENAME|-let} [-e COMMAND]
- -e exec the rest of the command line
- -i SECONDS delay after each line sent
-w SECONDS timeout for connection
- -f filename use file (ala /dev/ttyS0) instead of network
- -l listen for incoming connection (twice for persistent connection)
-p local port number
- -s local source address
+ -s local ipv4 address
-q SECONDS quit this many seconds after EOF on stdin.
-
- Use -l twice with -e for a quick-and-dirty server.
+ -f use FILENAME (ala /dev/ttyS0) instead of network
Use "stty 115200 -F /dev/ttyS0 && stty raw -echo -ctlecho" with
netcat -f to connect to a serial port.
+
+
+config NETCAT_LISTEN
+ bool "netcat sever options (-let)"
+ default y
+ depends on NETCAT
+ help
+ -t allocate tty (must come before -l or -L)
+ -l listen for one incoming connection.
+ -L listen for multiple incoming connections (server mode).
+
+ Any additional command line arguments after -l or -L are executed
+ to handle each incoming connection. If none, the connection is
+ forwarded to stdin/stdout.
+
+ For a quick-and-dirty server, try something like:
+ netcat -s 127.0.0.1 -p 1234 -tL /bin/bash -l
*/
#include "toys.h"
@@ -38,54 +50,65 @@ DEFINE_GLOBALS(
long quit_delay; // -q Exit after EOF from stdin after # seconds.
char *source_address; // -s Bind to a specific source address.
long port; // -p Bind to a specific source port.
- long listen; // -l Listen for connection instead of dialing out.
long wait; // -w Wait # seconds for a connection.
- long delay; // -i delay between lines sent
)
#define TT this.netcat
+#define FLAG_f 1
+#define FLAG_L 32
+#define FLAG_l 64
+#define FLAG_t 128
+
static void timeout(int signum)
{
- error_exit("Timeout");
+ if (TT.wait) error_exit("Timeout");
+ exit(0);
+}
+
+static void set_alarm(int seconds)
+{
+ signal(SIGALRM, seconds ? timeout : SIG_DFL);
+ alarm(seconds);
}
// Translate x.x.x.x numeric IPv4 address, or else DNS lookup an IPv4 name.
-void lookup_name(char *name, uint32_t *result)
+static void lookup_name(char *name, uint32_t *result)
{
struct hostent *hostbyname;
- hostbyname = gethostbyname(*toys.optargs);
- if (!hostbyname) error_exit("name lookup failed");
+ hostbyname = gethostbyname(name);
+ if (!hostbyname) error_exit("no host '%s'", name);
*result = *(uint32_t *)*hostbyname->h_addr_list;
}
// Worry about a fancy lookup later.
-void lookup_port(char *str, uint16_t *port)
+static void lookup_port(char *str, uint16_t *port)
{
*port = SWAP_BE16(atoi(str));
}
void netcat_main(void)
{
- int sockfd, pollcount;
+ int sockfd=-1, pollcount=2;
struct pollfd pollfds[2];
- if (TT.wait) {
- signal(SIGALRM, timeout);
- alarm(TT.wait);
- }
+ pollfds[0].events = pollfds[1].events = POLLIN;
+ set_alarm(TT.wait);
+
+ // The argument parsing logic can't make "<2" conditional on other
+ // arguments like -f and -l, so we do it by hand here.
+ if ((toys.optflags&FLAG_f) && toys.optc!=1) toys.exithelp++;
+ if (!(toys.optflags&(FLAG_l|FLAG_L)) && toys.optc!=2) toys.exithelp++;
+
+ if (toys.exithelp) error_exit("Argument count wrong");
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");
- }
+ pollfds[1].fd = 0;
// Setup socket
sockfd = socket(AF_INET, SOCK_STREAM, 0);
@@ -95,29 +118,95 @@ void netcat_main(void)
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)))
+ if (TT.source_address || TT.port) {
+ address.sin_port = SWAP_BE16(TT.port);
+ if (TT.source_address)
+ lookup_name(TT.source_address, (uint32_t *)&address.sin_addr);
+ if (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;
+ // Dial out
+
+ if (!CFG_NETCAT_LISTEN || !(toys.optflags&(FLAG_L|FLAG_l))) {
+ // 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;
+
+ // Listen for incoming connections
+
+ } else {
+ socklen_t len = sizeof(address);
+
+ if (listen(sockfd, 5)) error_exit("listen");
+ if (!TT.port) {
+ getsockname(sockfd, &address, &len);
+ printf("%d\n", SWAP_BE16(address.sin_port));
+ fflush(stdout);
+ }
+ // Do we need to defer calling accept() to the new thread
+ // because -l has arguments and we want it to return immediately?
+ temp = 0;
+ if ((toys.optflags&FLAG_l) && toys.optc) temp++;
+
+ for (;;) {
+ pid_t child = 0;
+
+ // For -l, call accept from the _new_ thread.
+
+ if (temp != 1) {
+ pollfds[0].fd = accept(sockfd, (struct sockaddr *)&address,
+ &len);
+ if (pollfds[0].fd<0) perror_exit("accept");
+
+ if (temp==2) {
+ close(sockfd);
+ break;
+ }
+ } else temp++;
+
+ // Do we need a tty?
+
+ if (toys.optflags&FLAG_t)
+ child = forkpty(&(pollfds[1].fd), NULL, NULL, NULL);
+
+ // Do we need to fork and/or redirect for exec?
+
+ else {
+ if (temp || (toys.optflags&FLAG_L)) child = fork();
+ if (!child && toys.optc) {
+ int fd = pollfds[0].fd;
+
+ if (!temp) close(sockfd);
+ dup2(fd, 0);
+ dup2(fd, 1);
+ dup2(fd, 2);
+ if (fd>2) close(fd);
+ }
+ }
+
+ if (child<0) error_msg("Fork failed\n");
+ if (child<1) {
+ if (!temp) break;
+ continue;
+ }
+ if (temp) exit(0);
+ close(pollfds[0].fd);
+ }
+ }
}
// We have a connection. Disarm timeout.
- if (TT.wait) {
- alarm(0);
- signal(SIGALRM, SIG_DFL);
- }
+ // (Does not play well with -L, but what _should_ that do?)
+ set_alarm(0);
- pollcount = 2;
- pollfds[1].fd = 0;
- pollfds[0].events = pollfds[1].events = POLLIN;
+ if (CFG_NETCAT_LISTEN && (toys.optflags&(FLAG_L|FLAG_l) && toys.optc)) {
+ execvp(*toys.optargs, toys.optargs);
+ error_exit("Exec failed");
+ }
// Poll loop copying stdin->socket and socket->stdout.
for (;;) {
@@ -133,16 +222,19 @@ void netcat_main(void)
}
if (pollfds[i].revents & POLLHUP) {
dohupnow:
- // Close half-connect. This is needed for things like
- // "echo GET / | netcat landley.net 80" to work.
+ // Close half-connection. This is needed for things like
+ // "echo GET / | netcat landley.net 80"
if (i) {
shutdown(pollfds[0].fd, SHUT_WR);
pollcount--;
+ set_alarm(TT.quit_delay);
} else goto cleanup;
}
}
}
cleanup:
- close(pollfds[0].fd);
-// close(sockfd);
+ if (CFG_TOYBOX_FREE) {
+ close(pollfds[0].fd);
+ close(sockfd);
+ }
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-14 08:00:58 +0000