Contents of /tags/mkinitrd-6_2_1/busybox/networking/pscan.c
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Sun May 30 12:16:23 2010 UTC (14 years, 4 months ago) by niro
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File size: 4651 byte(s)
Sun May 30 12:16:23 2010 UTC (14 years, 4 months ago) by niro
File MIME type: text/plain
File size: 4651 byte(s)
tagged 'mkinitrd-6_2_1'
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 | |
20 | static 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 | |
33 | int pscan_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
34 | int pscan_main(int argc UNUSED_PARAM, 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 | const char *result_str; |
46 | len_and_sockaddr *lsap; |
47 | int s; |
48 | unsigned opt; |
49 | unsigned port, max_port, nports; |
50 | unsigned closed_ports = 0; |
51 | unsigned open_ports = 0; |
52 | /* all in usec */ |
53 | unsigned timeout; |
54 | unsigned min_rtt; |
55 | unsigned rtt_4; |
56 | unsigned start, diff; |
57 | |
58 | opt_complementary = "=1"; /* exactly one non-option */ |
59 | opt = getopt32(argv, "cbp:P:t:T:", &opt_min_port, &opt_max_port, &opt_timeout, &opt_min_rtt); |
60 | argv += optind; |
61 | max_port = xatou_range(opt_max_port, 1, 65535); |
62 | port = xatou_range(opt_min_port, 1, max_port); |
63 | nports = max_port - port + 1; |
64 | min_rtt = xatou_range(opt_min_rtt, 1, INT_MAX/1000 / 4) * 1000; |
65 | timeout = xatou_range(opt_timeout, 1, INT_MAX/1000 / 4) * 1000; |
66 | /* Initial rtt is BIG: */ |
67 | rtt_4 = timeout; |
68 | |
69 | DMSG("min_rtt %u timeout %u", min_rtt, timeout); |
70 | |
71 | lsap = xhost2sockaddr(*argv, port); |
72 | printf("Scanning %s ports %u to %u\n Port\tProto\tState\tService\n", |
73 | *argv, port, max_port); |
74 | |
75 | for (; port <= max_port; port++) { |
76 | DMSG("rtt %u", rtt_4); |
77 | |
78 | /* The SOCK_STREAM socket type is implemented on the TCP/IP protocol. */ |
79 | set_nport(lsap, htons(port)); |
80 | s = xsocket(lsap->u.sa.sa_family, SOCK_STREAM, 0); |
81 | /* We need unblocking socket so we don't need to wait for ETIMEOUT. */ |
82 | /* Nonblocking connect typically "fails" with errno == EINPROGRESS */ |
83 | ndelay_on(s); |
84 | |
85 | DMSG("connect to port %u", port); |
86 | result_str = NULL; |
87 | start = MONOTONIC_US(); |
88 | if (connect(s, &lsap->u.sa, lsap->len) == 0) { |
89 | /* Unlikely, for me even localhost fails :) */ |
90 | DMSG("connect succeeded"); |
91 | goto open; |
92 | } |
93 | /* Check for untypical errors... */ |
94 | if (errno != EAGAIN && errno != EINPROGRESS |
95 | && errno != ECONNREFUSED |
96 | ) { |
97 | bb_perror_nomsg_and_die(); |
98 | } |
99 | |
100 | diff = 0; |
101 | while (1) { |
102 | if (errno == ECONNREFUSED) { |
103 | if (opt & 1) /* -c: show closed too */ |
104 | result_str = "closed"; |
105 | closed_ports++; |
106 | break; |
107 | } |
108 | DERR("port %u errno %d @%u", port, errno, diff); |
109 | |
110 | if (diff > rtt_4) { |
111 | if (opt & 2) /* -b: show blocked too */ |
112 | result_str = "blocked"; |
113 | break; |
114 | } |
115 | /* Can sleep (much) longer than specified delay. |
116 | * We check rtt BEFORE we usleep, otherwise |
117 | * on localhost we'll have no writes done (!) |
118 | * before we exceed (rather small) rtt */ |
119 | usleep(rtt_4/8); |
120 | open: |
121 | diff = MONOTONIC_US() - start; |
122 | DMSG("write to port %u @%u", port, diff - start); |
123 | if (write(s, " ", 1) >= 0) { /* We were able to write to the socket */ |
124 | open_ports++; |
125 | result_str = "open"; |
126 | break; |
127 | } |
128 | } |
129 | DMSG("out of loop @%u", diff); |
130 | if (result_str) |
131 | printf("%5u" "\t" "tcp" "\t" "%s" "\t" "%s" "\n", |
132 | port, result_str, port_name(port)); |
133 | |
134 | /* Estimate new rtt - we don't want to wait entire timeout |
135 | * for each port. *4 allows for rise in net delay. |
136 | * We increase rtt quickly (rtt_4*4), decrease slowly |
137 | * (diff is at least rtt_4/8, *4 == rtt_4/2) |
138 | * because we don't want to accidentally miss ports. */ |
139 | rtt_4 = diff * 4; |
140 | if (rtt_4 < min_rtt) |
141 | rtt_4 = min_rtt; |
142 | if (rtt_4 > timeout) |
143 | rtt_4 = timeout; |
144 | /* Clean up */ |
145 | close(s); |
146 | } |
147 | if (ENABLE_FEATURE_CLEAN_UP) free(lsap); |
148 | |
149 | printf("%d closed, %d open, %d timed out (or blocked) ports\n", |
150 | closed_ports, |
151 | open_ports, |
152 | nports - (closed_ports + open_ports)); |
153 | return EXIT_SUCCESS; |
154 | } |