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pscan: add -c, -b: report closed, blocked ports

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This commit is contained in:
Denis Vlasenko 2008-03-23 14:46:14 +00:00
parent 69ca5a70fd
commit 715c16ab0a
2 changed files with 34 additions and 16 deletions
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4
include/usage.h
View File

@ -3019,10 +3019,12 @@
" 2990 andersen andersen R ps\n"
#define pscan_trivial_usage \
"[-p MIN_PORT] [-P MAX_PORT] [-t TIMEOUT] [-T MIN_RTT] HOST"
"[-cb] [-p MIN_PORT] [-P MAX_PORT] [-t TIMEOUT] [-T MIN_RTT] HOST"
#define pscan_full_usage \
"Scan a host, print all open ports\n" \
"\nOptions:" \
"\n -c Show closed ports too" \
"\n -c Show blocked ports too" \
"\n -p Scan from this port (default 1)" \
"\n -P Scan up to this port (default 1024)" \
"\n -t Timeout (default 5000 ms)" \

46
networking/pscan.c
View File

@ -42,8 +42,10 @@ int pscan_main(int argc ATTRIBUTE_UNUSED, char **argv)
* Rule of thumb: with min_rtt of N msec, scanning 1000 ports
* will take N seconds at absolute minimum */
const char *opt_min_rtt = "5"; /* -T: default min rtt in msec */
const char *result_str;
len_and_sockaddr *lsap;
int s;
unsigned opt;
unsigned port, max_port, nports;
unsigned closed_ports = 0;
unsigned open_ports = 0;
@ -51,16 +53,18 @@ int pscan_main(int argc ATTRIBUTE_UNUSED, char **argv)
unsigned timeout;
unsigned min_rtt;
unsigned rtt_4;
unsigned start;
unsigned start, diff;
opt_complementary = "=1"; /* exactly one non-option */
getopt32(argv, "p:P:t:T:", &opt_min_port, &opt_max_port, &opt_timeout, &opt_min_rtt);
opt = getopt32(argv, "cbp:P:t:T:", &opt_min_port, &opt_max_port, &opt_timeout, &opt_min_rtt);
argv += optind;
max_port = xatou_range(opt_max_port, 1, 65535);
port = xatou_range(opt_min_port, 1, max_port);
nports = max_port - port + 1;
rtt_4 = timeout = xatou_range(opt_timeout, 1, INT_MAX/1000 / 4) * 1000;
min_rtt = xatou_range(opt_min_rtt, 1, INT_MAX/1000 / 4) * 1000;
timeout = xatou_range(opt_timeout, 1, INT_MAX/1000 / 4) * 1000;
/* Initial rtt is BIG: */
rtt_4 = timeout;
DMSG("min_rtt %u timeout %u", min_rtt, timeout);
@ -74,11 +78,12 @@ int pscan_main(int argc ATTRIBUTE_UNUSED, char **argv)
/* The SOCK_STREAM socket type is implemented on the TCP/IP protocol. */
set_nport(lsap, htons(port));
s = xsocket(lsap->u.sa.sa_family, SOCK_STREAM, 0);
/* We need unblocking socket so we don't need to wait for ETIMEOUT. */
/* Nonblocking connect typically "fails" with errno == EINPROGRESS */
ndelay_on(s);
DMSG("connect to port %u", port);
result_str = NULL;
start = MONOTONIC_US();
if (connect(s, &lsap->u.sa, lsap->len) == 0) {
/* Unlikely, for me even localhost fails :) */
@ -92,35 +97,46 @@ int pscan_main(int argc ATTRIBUTE_UNUSED, char **argv)
bb_perror_nomsg_and_die();
}
diff = 0;
while (1) {
if (errno == ECONNREFUSED) {
DMSG("port %u: ECONNREFUSED", port);
if (opt & 1) /* -c: show closed too */
result_str = "closed";
closed_ports++;
break;
}
DERR("port %u errno %d @%u", port, errno, MONOTONIC_US() - start);
if ((MONOTONIC_US() - start) > rtt_4)
DERR("port %u errno %d @%u", port, errno, diff);
if (diff > rtt_4) {
if (opt & 2) /* -b: show blocked too */
result_str = "blocked";
break;
}
/* Can sleep (much) longer than specified delay.
* We check rtt BEFORE we usleep, otherwise
* on localhost we'll do zero writes done (!)
* on localhost we'll have no writes done (!)
* before we exceed (rather small) rtt */
usleep(rtt_4/8);
DMSG("write to port %u @%u", port, MONOTONIC_US() - start);
if (write(s, " ", 1) >= 0) { /* We were able to write to the socket */
open:
diff = MONOTONIC_US() - start;
DMSG("write to port %u @%u", port, diff - start);
if (write(s, " ", 1) >= 0) { /* We were able to write to the socket */
open_ports++;
printf("%5u\ttcp\topen\t%s\n", port, port_name(port));
result_str = "open";
break;
}
}
DMSG("out of loop @%u", MONOTONIC_US() - start);
DMSG("out of loop @%u", diff);
if (result_str)
printf("%5u" "\t" "tcp" "\t" "%s" "\t" "%s" "\n",
port, result_str, port_name(port));
/* Estimate new rtt - we don't want to wait entire timeout
* for each port. *4 allows for rise in net delay.
* We increase rtt quickly (*4), decrease slowly (4/8 == 1/2)
* We increase rtt quickly (rtt_4*4), decrease slowly
* (diff is at least rtt_4/8, *4 == rtt_4/2)
* because we don't want to accidentally miss ports. */
rtt_4 = (MONOTONIC_US() - start) * 4;
rtt_4 = diff * 4;
if (rtt_4 < min_rtt)
rtt_4 = min_rtt;
if (rtt_4 > timeout)
@ -130,7 +146,7 @@ int pscan_main(int argc ATTRIBUTE_UNUSED, char **argv)
}
if (ENABLE_FEATURE_CLEAN_UP) free(lsap);
printf("%d closed, %d open, %d timed out ports\n",
printf("%d closed, %d open, %d timed out (or blocked) ports\n",
closed_ports,
open_ports,
nports - (closed_ports + open_ports));