2 * Pscan is a mini port scanner implementation for busybox
4 * Copyright 2007 Tito Ragusa <farmatito@tiscali.it>
6 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
9 //usage:#define pscan_trivial_usage
10 //usage: "[-cb] [-p MIN_PORT] [-P MAX_PORT] [-t TIMEOUT] [-T MIN_RTT] HOST"
11 //usage:#define pscan_full_usage "\n\n"
12 //usage: "Scan a host, print all open ports\n"
14 //usage: "\n -c Show closed ports too"
15 //usage: "\n -b Show blocked ports too"
16 //usage: "\n -p Scan from this port (default 1)"
17 //usage: "\n -P Scan up to this port (default 1024)"
18 //usage: "\n -t Timeout (default 5000 ms)"
19 //usage: "\n -T Minimum rtt (default 5 ms, increase for congested hosts)"
25 #define DMSG(...) bb_error_msg(__VA_ARGS__)
26 #define DERR(...) bb_perror_msg(__VA_ARGS__)
28 #define DMSG(...) ((void)0)
29 #define DERR(...) ((void)0)
32 static const char *port_name(unsigned port)
34 struct servent *server;
36 server = getservbyport(htons(port), NULL);
38 return server->s_name;
42 /* We don't expect to see 1000+ seconds delay, unsigned is enough */
43 #define MONOTONIC_US() ((unsigned)monotonic_us())
45 int pscan_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
46 int pscan_main(int argc UNUSED_PARAM, char **argv)
48 const char *opt_max_port = "1024"; /* -P: default max port */
49 const char *opt_min_port = "1"; /* -p: default min port */
50 const char *opt_timeout = "5000"; /* -t: default timeout in msec */
51 /* We estimate rtt and wait rtt*4 before concluding that port is
52 * totally blocked. min rtt of 5 ms may be too low if you are
53 * scanning an Internet host behind saturated/traffic shaped link.
54 * Rule of thumb: with min_rtt of N msec, scanning 1000 ports
55 * will take N seconds at absolute minimum */
56 const char *opt_min_rtt = "5"; /* -T: default min rtt in msec */
57 const char *result_str;
58 len_and_sockaddr *lsap;
61 unsigned port, max_port, nports;
62 unsigned closed_ports = 0;
63 unsigned open_ports = 0;
70 opt_complementary = "=1"; /* exactly one non-option */
71 opt = getopt32(argv, "cbp:P:t:T:", &opt_min_port, &opt_max_port, &opt_timeout, &opt_min_rtt);
73 max_port = xatou_range(opt_max_port, 1, 65535);
74 port = xatou_range(opt_min_port, 1, max_port);
75 nports = max_port - port + 1;
76 min_rtt = xatou_range(opt_min_rtt, 1, INT_MAX/1000 / 4) * 1000;
77 timeout = xatou_range(opt_timeout, 1, INT_MAX/1000 / 4) * 1000;
78 /* Initial rtt is BIG: */
81 DMSG("min_rtt %u timeout %u", min_rtt, timeout);
83 lsap = xhost2sockaddr(*argv, port);
84 printf("Scanning %s ports %u to %u\n Port\tProto\tState\tService\n",
85 *argv, port, max_port);
87 for (; port <= max_port; port++) {
88 DMSG("rtt %u", rtt_4);
90 /* The SOCK_STREAM socket type is implemented on the TCP/IP protocol. */
91 set_nport(&lsap->u.sa, htons(port));
92 s = xsocket(lsap->u.sa.sa_family, SOCK_STREAM, 0);
93 /* We need unblocking socket so we don't need to wait for ETIMEOUT. */
94 /* Nonblocking connect typically "fails" with errno == EINPROGRESS */
97 DMSG("connect to port %u", port);
99 start = MONOTONIC_US();
100 if (connect(s, &lsap->u.sa, lsap->len) == 0) {
101 /* Unlikely, for me even localhost fails :) */
102 DMSG("connect succeeded");
105 /* Check for untypical errors... */
106 if (errno != EAGAIN && errno != EINPROGRESS
107 && errno != ECONNREFUSED
109 bb_perror_nomsg_and_die();
114 if (errno == ECONNREFUSED) {
115 if (opt & 1) /* -c: show closed too */
116 result_str = "closed";
120 DERR("port %u errno %d @%u", port, errno, diff);
123 if (opt & 2) /* -b: show blocked too */
124 result_str = "blocked";
127 /* Can sleep (much) longer than specified delay.
128 * We check rtt BEFORE we usleep, otherwise
129 * on localhost we'll have no writes done (!)
130 * before we exceed (rather small) rtt */
133 diff = MONOTONIC_US() - start;
134 DMSG("write to port %u @%u", port, diff - start);
135 if (write(s, " ", 1) >= 0) { /* We were able to write to the socket */
141 DMSG("out of loop @%u", diff);
143 printf("%5u" "\t" "tcp" "\t" "%s" "\t" "%s" "\n",
144 port, result_str, port_name(port));
146 /* Estimate new rtt - we don't want to wait entire timeout
147 * for each port. *4 allows for rise in net delay.
148 * We increase rtt quickly (rtt_4*4), decrease slowly
149 * (diff is at least rtt_4/8, *4 == rtt_4/2)
150 * because we don't want to accidentally miss ports. */
159 if (ENABLE_FEATURE_CLEAN_UP) free(lsap);
161 printf("%d closed, %d open, %d timed out (or blocked) ports\n",
164 nports - (closed_ports + open_ports));