Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

netcat: Implement zero I/O mode #478

Closed
wants to merge 1 commit into from
Closed

netcat: Implement zero I/O mode #478

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Jump to
Jump to file
Failed to load files.
Diff view
Diff view
16 changes: 12 additions & 4 deletions toys/net/netcat.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@
*
* TODO: genericize for telnet/microcom/tail-f, fix -t

USE_NETCAT(NEWTOY(netcat, "^tElLw#<1W#<1p#<1>65535q#<1s:f:46uUn[!tlL][!Lw][!Lu][!46U]", TOYFLAG_BIN))
USE_NETCAT(NEWTOY(netcat, "^tElLw#<1W#<1p#<1>65535q#<1s:f:46uUnvz[!tlL][!Lw][!Lu][!46U]", TOYFLAG_BIN))
USE_NETCAT(OLDTOY(nc, netcat, TOYFLAG_USR|TOYFLAG_BIN))

config NETCAT
Expand All @@ -26,10 +26,12 @@ config NETCAT
-q Quit SECONDS after EOF on stdin, even if stdout hasn't closed yet
-s Local source address
-t Allocate tty
-v Verbose
-u Use UDP
-U Use a UNIX domain socket
-W SECONDS timeout for more data on an idle connection
-w SECONDS timeout to establish connection
-z zero-I/O mode [used for scanning]

When listening the COMMAND line is executed as a child process to handle
an incoming connection. With no COMMAND -l forwards the connection
Expand Down Expand Up @@ -106,9 +108,15 @@ void netcat_main(void)
else {
// Setup socket
if (!FLAG(l) && !FLAG(L)) {
if (FLAG(U)) sockfd = usock(toys.optargs[0], type, 1);
else sockfd = xconnectany(xgetaddrinfo(toys.optargs[0],
toys.optargs[1], family, type, 0, AI_NUMERICHOST*FLAG(n)));
char *host = toys.optargs[0];
char *port = toys.optargs[1];
if (FLAG(U)) sockfd = usock(host, type, 1);
else sockfd = xconnectany(xgetaddrinfo(host, port, family, type, 0, AI_NUMERICHOST*FLAG(n)));

if (FLAG(v)) printf("%s:%s [open]\n", host, port);

// Do not perform any I/O in zero mode
if (FLAG(z)) goto cleanup;

// We have a connection. Disarm timeout and start poll/send loop.
alarm(0);
Expand Down