source: MondoRescue/branches/2.2.5/mindi-busybox/networking/pscan.c @ 1765

Last change on this file since 1765 was 1765, checked in by Bruno Cornec, 12 years ago

Update to busybox 1.7.2

  • Property svn:eol-style set to native
File size: 4.2 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 the GPL v2 or later, see the file LICENSE in this tarball.
7 */
8
9#include "libbb.h"
10
11/* debugging */
12#ifdef DEBUG_PSCAN
13#define DMSG(...) bb_error_msg(__VA_ARGS__)
14#define DERR(...) bb_perror_msg(__VA_ARGS__)
15#else
16#define DMSG(...) ((void)0)
17#define DERR(...) ((void)0)
18#endif
19
20static const char *port_name(unsigned port)
21{
22    struct servent *server;
23
24    server = getservbyport(htons(port), NULL);
25    if (server)
26        return server->s_name;
27    return "unknown";
28}
29
30/* We don't expect to see 1000+ seconds delay, unsigned is enough */
31#define MONOTONIC_US() ((unsigned)monotonic_us())
32
33int pscan_main(int argc, char **argv);
34int pscan_main(int argc, char **argv)
35{
36    const char *opt_max_port = "1024";      /* -P: default max port */
37    const char *opt_min_port = "1";         /* -p: default min port */
38    const char *opt_timeout = "5000";       /* -t: default timeout in msec */
39    /* We estimate rtt and wait rtt*4 before concluding that port is
40     * totally blocked. min rtt of 5 ms may be too low if you are
41     * scanning an Internet host behind saturated/traffic shaped link.
42     * Rule of thumb: with min_rtt of N msec, scanning 1000 ports
43     * will take N seconds at absolute minimum */
44    const char *opt_min_rtt = "5";          /* -T: default min rtt in msec */
45    len_and_sockaddr *lsap;
46    int s;
47    unsigned port, max_port, nports;
48    unsigned closed_ports = 0;
49    unsigned open_ports = 0;
50    /* all in usec */
51    unsigned timeout;
52    unsigned min_rtt;
53    unsigned rtt_4;
54    unsigned start;
55
56    opt_complementary = "=1"; /* exactly one non-option */
57    getopt32(argv, "p:P:t:T:", &opt_min_port, &opt_max_port, &opt_timeout, &opt_min_rtt);
58    argv += optind;
59    max_port = xatou_range(opt_max_port, 1, 65535);
60    port = xatou_range(opt_min_port, 1, max_port);
61    nports = max_port - port + 1;
62    rtt_4 = timeout = xatou_range(opt_timeout, 1, INT_MAX/1000 / 4) * 1000;
63    min_rtt = xatou_range(opt_min_rtt, 1, INT_MAX/1000 / 4) * 1000;
64
65    DMSG("min_rtt %u timeout %u", min_rtt, timeout);
66
67    lsap = xhost2sockaddr(*argv, port);
68    printf("Scanning %s ports %u to %u\n Port\tProto\tState\tService\n",
69            *argv, port, max_port);
70
71    for (; port <= max_port; port++) {
72        DMSG("rtt %u", rtt_4);
73
74        /* The SOCK_STREAM socket type is implemented on the TCP/IP protocol. */
75        set_nport(lsap, htons(port));
76        s = xsocket(lsap->sa.sa_family, SOCK_STREAM, 0);
77
78        /* We need unblocking socket so we don't need to wait for ETIMEOUT. */
79        /* Nonblocking connect typically "fails" with errno == EINPROGRESS */
80        ndelay_on(s);
81        DMSG("connect to port %u", port);
82        start = MONOTONIC_US();
83        if (connect(s, &lsap->sa, lsap->len) == 0) {
84            /* Unlikely, for me even localhost fails :) */
85            DMSG("connect succeeded");
86            goto open;
87        }
88        /* Check for untypical errors... */
89        if (errno != EAGAIN && errno != EINPROGRESS
90         && errno != ECONNREFUSED
91        ) {
92            bb_perror_nomsg_and_die();
93        }
94
95        while (1) {
96            if (errno == ECONNREFUSED) {
97                DMSG("port %u: ECONNREFUSED", port);
98                closed_ports++;
99                break;
100            }
101            DERR("port %u errno %d @%u", port, errno, MONOTONIC_US() - start);
102            if ((MONOTONIC_US() - start) > rtt_4)
103                break;
104            /* Can sleep (much) longer than specified delay.
105             * We check rtt BEFORE we usleep, otherwise
106             * on localhost we'll do zero writes done (!)
107             * before we exceed (rather small) rtt */
108            usleep(rtt_4/8);
109            DMSG("write to port %u @%u", port, MONOTONIC_US() - start);
110            if (write(s, " ", 1) >= 0) { /* We were able to write to the socket */
111 open:
112                open_ports++;
113                printf("%5u\ttcp\topen\t%s\n", port, port_name(port));
114                break;
115            }
116        }
117        DMSG("out of loop @%u", MONOTONIC_US() - start);
118
119        /* Estimate new rtt - we don't want to wait entire timeout
120         * for each port. *4 allows for rise in net delay.
121         * We increase rtt quickly (*4), decrease slowly (4/8 == 1/2)
122         * because we don't want to accidentally miss ports. */
123        rtt_4 = (MONOTONIC_US() - start) * 4;
124        if (rtt_4 < min_rtt)
125            rtt_4 = min_rtt;
126        if (rtt_4 > timeout)
127            rtt_4 = timeout;
128        /* Clean up */
129        close(s);
130    }
131    if (ENABLE_FEATURE_CLEAN_UP) free(lsap);
132
133    printf("%d closed, %d open, %d timed out ports\n",
134                    closed_ports,
135                    open_ports,
136                    nports - (closed_ports + open_ports));
137    return EXIT_SUCCESS;
138}
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