1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
|
/* netcat.c - Forward stdin/stdout to a file or network connection.
*
* Copyright 2007 Rob Landley <rob@landley.net>
*
* TODO: udp, ipv6, genericize for telnet/microcom/tail-f
* fix -t, xconnect
* netcat -L zombies
USE_NETCAT(OLDTOY(nc, netcat, TOYFLAG_USR|TOYFLAG_BIN))
USE_NETCAT(NEWTOY(netcat, USE_NETCAT_LISTEN("^tlL")"w#<1W#<1p#<1>65535q#<1s:f:46u"USE_NETCAT_LISTEN("[!tlL][!Lw]")"[!46]", TOYFLAG_BIN))
config NETCAT
bool "netcat"
default y
help
usage: netcat [-46] [-u] [-wpq #] [-s addr] {IPADDR PORTNUM|-f FILENAME}
-4 Force IPv4
-6 Force IPv6
-f Use FILENAME (ala /dev/ttyS0) instead of network
-p Local port number
-q Quit SECONDS after EOF on stdin, even if stdout hasn't closed yet
-s Local source address
-u Use UDP
-w SECONDS timeout to establish connection
-W SECONDS timeout for more data on an idle connection
Use "stty 115200 -F /dev/ttyS0 && stty raw -echo -ctlecho" with
netcat -f to connect to a serial port.
config NETCAT_LISTEN
bool "netcat server options (-let)"
default y
depends on NETCAT
help
usage: netcat [-t] [-lL COMMAND...]
-l Listen for one incoming connection
-L Listen for multiple incoming connections (server mode)
-t Allocate tty (must come before -l or -L)
The command line after -l or -L is executed (as a child process) to handle
each incoming connection. If blank -l waits for a connection and forwards
it to stdin/stdout. If no -p specified, -l prints port it bound to and
backgrounds itself (returning immediately).
For a quick-and-dirty server, try something like:
netcat -s 127.0.0.1 -p 1234 -tL /bin/bash -l
*/
#define FOR_netcat
#include "toys.h"
GLOBALS(
char *f, *s;
long q, p, W, w;
)
static void timeout(int signum)
{
if (TT.w) error_exit("Timeout");
xexit();
}
static void set_alarm(int seconds)
{
xsignal(SIGALRM, seconds ? timeout : SIG_DFL);
alarm(seconds);
}
void netcat_main(void)
{
int sockfd = -1, in1 = 0, in2 = 0, out1 = 1, out2 = 1;
int family = AF_UNSPEC, type = SOCK_STREAM;
pid_t child;
// Addjust idle and quit_delay to ms or -1 for no timeout
TT.W = TT.W ? TT.W*1000 : -1;
TT.q = TT.q ? TT.q*1000 : -1;
set_alarm(TT.w);
// The argument parsing logic can't make "<2" conditional on other
// arguments like -f and -l, so do it by hand here.
if ((toys.optflags&FLAG_f) ? toys.optc :
(!(toys.optflags&(FLAG_l|FLAG_L)) && toys.optc!=2))
help_exit("bad argument count");
if (toys.optflags&FLAG_4) family = AF_INET;
else if (toys.optflags&FLAG_6) family = AF_INET6;
if (toys.optflags&FLAG_u) type = SOCK_DGRAM;
if (TT.f) in1 = out2 = xopen(TT.f, O_RDWR);
else {
// Setup socket
if (!(toys.optflags&(FLAG_L|FLAG_l))) {
struct addrinfo *addr = xgetaddrinfo(toys.optargs[0], toys.optargs[1],
family, type, 0, 0);
sockfd = xconnect(addr);
// We have a connection. Disarm timeout.
set_alarm(0);
in1 = out2 = sockfd;
pollinate(in1, in2, out1, out2, TT.W, TT.q);
} else {
// Listen for incoming connections
struct sockaddr* address = (void*)toybuf;
socklen_t len = sizeof(struct sockaddr_storage);
sprintf(toybuf, "%ld", TT.p);
sockfd = xbind(xgetaddrinfo(TT.s, toybuf, family, type, 0, 0));
if (listen(sockfd, 5)) error_exit("listen");
if (!TT.p) {
short port_be;
getsockname(sockfd, address, &len);
if (address->sa_family == AF_INET)
port_be = ((struct sockaddr_in*)address)->sin_port;
else if (address->sa_family == AF_INET6)
port_be = ((struct sockaddr_in6*)address)->sin6_port;
else
perror_exit("getsockname: bad family");
printf("%d\n", SWAP_BE16(port_be));
fflush(stdout);
// Return immediately if no -p and -Ll has arguments, so wrapper
// script can use port number.
if (CFG_TOYBOX_FORK && toys.optc && xfork()) goto cleanup;
}
do {
child = 0;
in1 = out2 = accept(sockfd, (struct sockaddr *)address, &len);
if (in1<0) perror_exit("accept");
// We have a connection. Disarm timeout.
set_alarm(0);
if (toys.optc) {
// Do we need a tty?
// TODO nommu, and -t only affects server mode...? Only do -t with optc
// if (CFG_TOYBOX_FORK && (toys.optflags&FLAG_t))
// child = forkpty(&fdout, NULL, NULL, NULL);
// else
// Do we need to fork and/or redirect for exec?
if (toys.optflags&FLAG_L) NOEXIT(child = XVFORK());
if (child) {
close(in1);
continue;
}
dup2(in1, 0);
dup2(in1, 1);
if (toys.optflags&FLAG_L) dup2(in1, 2);
if (in1>2) close(in1);
xexec(toys.optargs);
}
pollinate(in1, in2, out1, out2, TT.W, TT.q);
close(in1);
} while (!(toys.optflags&FLAG_l));
}
}
cleanup:
if (CFG_TOYBOX_FREE) {
close(in1);
close(sockfd);
}
}
|
