source: branches/3.2/mindi-busybox/networking/pscan.c @ 3232

Last change on this file since 3232 was 3232, checked in by bruno, 6 years ago
  • Update mindi-busybox to 1.21.1
  • Property svn:eol-style set to native
File size: 5.1 KB
Line 
1/*
2 * Pscan is a mini port scanner implementation for busybox
3 *
4 * Copyright 2007 Tito Ragusa <farmatito@tiscali.it>
5 *
6 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
7 */
8
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"
13//usage:     "\n    -c  Show closed ports too"
14//usage:     "\n    -b  Show blocked ports too"
15//usage:     "\n    -p  Scan from this port (default 1)"
16//usage:     "\n    -P  Scan up to this port (default 1024)"
17//usage:     "\n    -t  Timeout (default 5000 ms)"
18//usage:     "\n    -T  Minimum rtt (default 5 ms, increase for congested hosts)"
19
20#include "libbb.h"
21
22/* debugging */
23#ifdef DEBUG_PSCAN
24#define DMSG(...) bb_error_msg(__VA_ARGS__)
25#define DERR(...) bb_perror_msg(__VA_ARGS__)
26#else
27#define DMSG(...) ((void)0)
28#define DERR(...) ((void)0)
29#endif
30
31static const char *port_name(unsigned port)
32{
33    struct servent *server;
34
35    server = getservbyport(htons(port), NULL);
36    if (server)
37        return server->s_name;
38    return "unknown";
39}
40
41/* We don't expect to see 1000+ seconds delay, unsigned is enough */
42#define MONOTONIC_US() ((unsigned)monotonic_us())
43
44int pscan_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
45int pscan_main(int argc UNUSED_PARAM, char **argv)
46{
47    const char *opt_max_port = "1024";      /* -P: default max port */
48    const char *opt_min_port = "1";         /* -p: default min port */
49    const char *opt_timeout = "5000";       /* -t: default timeout in msec */
50    /* We estimate rtt and wait rtt*4 before concluding that port is
51     * totally blocked. min rtt of 5 ms may be too low if you are
52     * scanning an Internet host behind saturated/traffic shaped link.
53     * Rule of thumb: with min_rtt of N msec, scanning 1000 ports
54     * will take N seconds at absolute minimum */
55    const char *opt_min_rtt = "5";          /* -T: default min rtt in msec */
56    const char *result_str;
57    len_and_sockaddr *lsap;
58    int s;
59    unsigned opt;
60    unsigned port, max_port, nports;
61    unsigned closed_ports = 0;
62    unsigned open_ports = 0;
63    /* all in usec */
64    unsigned timeout;
65    unsigned min_rtt;
66    unsigned rtt_4;
67    unsigned start, diff;
68
69    opt_complementary = "=1"; /* exactly one non-option */
70    opt = getopt32(argv, "cbp:P:t:T:", &opt_min_port, &opt_max_port, &opt_timeout, &opt_min_rtt);
71    argv += optind;
72    max_port = xatou_range(opt_max_port, 1, 65535);
73    port = xatou_range(opt_min_port, 1, max_port);
74    nports = max_port - port + 1;
75    min_rtt = xatou_range(opt_min_rtt, 1, INT_MAX/1000 / 4) * 1000;
76    timeout = xatou_range(opt_timeout, 1, INT_MAX/1000 / 4) * 1000;
77    /* Initial rtt is BIG: */
78    rtt_4 = timeout;
79
80    DMSG("min_rtt %u timeout %u", min_rtt, timeout);
81
82    lsap = xhost2sockaddr(*argv, port);
83    printf("Scanning %s ports %u to %u\n Port\tProto\tState\tService\n",
84            *argv, port, max_port);
85
86    for (; port <= max_port; port++) {
87        DMSG("rtt %u", rtt_4);
88
89        /* The SOCK_STREAM socket type is implemented on the TCP/IP protocol. */
90        set_nport(&lsap->u.sa, htons(port));
91        s = xsocket(lsap->u.sa.sa_family, SOCK_STREAM, 0);
92        /* We need unblocking socket so we don't need to wait for ETIMEOUT. */
93        /* Nonblocking connect typically "fails" with errno == EINPROGRESS */
94        ndelay_on(s);
95
96        DMSG("connect to port %u", port);
97        result_str = NULL;
98        start = MONOTONIC_US();
99        if (connect(s, &lsap->u.sa, lsap->len) == 0) {
100            /* Unlikely, for me even localhost fails :) */
101            DMSG("connect succeeded");
102            goto open;
103        }
104        /* Check for untypical errors... */
105        if (errno != EAGAIN && errno != EINPROGRESS
106         && errno != ECONNREFUSED
107        ) {
108            bb_perror_nomsg_and_die();
109        }
110
111        diff = 0;
112        while (1) {
113            if (errno == ECONNREFUSED) {
114                if (opt & 1) /* -c: show closed too */
115                    result_str = "closed";
116                closed_ports++;
117                break;
118            }
119            DERR("port %u errno %d @%u", port, errno, diff);
120
121            if (diff > rtt_4) {
122                if (opt & 2) /* -b: show blocked too */
123                    result_str = "blocked";
124                break;
125            }
126            /* Can sleep (much) longer than specified delay.
127             * We check rtt BEFORE we usleep, otherwise
128             * on localhost we'll have no writes done (!)
129             * before we exceed (rather small) rtt */
130            usleep(rtt_4/8);
131 open:
132            diff = MONOTONIC_US() - start;
133            DMSG("write to port %u @%u", port, diff - start);
134            if (write(s, " ", 1) >= 0) { /* We were able to write to the socket */
135                open_ports++;
136                result_str = "open";
137                break;
138            }
139        }
140        DMSG("out of loop @%u", diff);
141        if (result_str)
142            printf("%5u" "\t" "tcp" "\t" "%s" "\t" "%s" "\n",
143                    port, result_str, port_name(port));
144
145        /* Estimate new rtt - we don't want to wait entire timeout
146         * for each port. *4 allows for rise in net delay.
147         * We increase rtt quickly (rtt_4*4), decrease slowly
148         * (diff is at least rtt_4/8, *4 == rtt_4/2)
149         * because we don't want to accidentally miss ports. */
150        rtt_4 = diff * 4;
151        if (rtt_4 < min_rtt)
152            rtt_4 = min_rtt;
153        if (rtt_4 > timeout)
154            rtt_4 = timeout;
155        /* Clean up */
156        close(s);
157    }
158    if (ENABLE_FEATURE_CLEAN_UP) free(lsap);
159
160    printf("%d closed, %d open, %d timed out (or blocked) ports\n",
161                    closed_ports,
162                    open_ports,
163                    nports - (closed_ports + open_ports));
164    return EXIT_SUCCESS;
165}
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