ab47eeee6
Denis Vlasenko
2007-06-16
Subject
forgot svn add...
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networking/pscan.c+150 -0
| @@ -0,0 +1,150 @@ | |
| + | /* |
| + | * Pscan is a mini port scanner implementation for busybox |
| + | * |
| + | * Copyright 2007 Tito Ragusa <[email protected]> |
| + | * |
| + | * Licensed under the GPL v2 or later, see the file LICENSE in this tarball. |
| + | */ |
| + | |
| + | #include "libbb.h" |
| + | |
| + | /* debugging */ |
| + | #ifdef DEBUG_PSCAN |
| + | #define DMSG(...) bb_error_msg(__VA_ARGS__) |
| + | #define DERR(...) bb_perror_msg(__VA_ARGS__) |
| + | #else |
| + | #define DMSG(...) ((void)0) |
| + | #define DERR(...) ((void)0) |
| + | #endif |
| + | |
| + | /* return time in usec */ |
| + | // TODO: move to libbb and use in traceroute, zcip, arping etc |
| + | // (maybe also use absolute monotonic clock - no time warps |
| + | // due to admin resetting date/time?) |
| + | static unsigned gettimeofday_us(void) |
| + | { |
| + | struct timeval now; |
| + | |
| + | if (gettimeofday(&now, NULL)) |
| + | return 0; |
| + | return (now.tv_sec * 1000000 + now.tv_usec); |
| + | } |
| + | |
| + | static const char *port_name(unsigned port) |
| + | { |
| + | struct servent *server; |
| + | |
| + | server = getservbyport(htons(port), NULL); |
| + | if (server) |
| + | return server->s_name; |
| + | return "unknown"; |
| + | } |
| + | |
| + | int pscan_main(int argc, char **argv); |
| + | int pscan_main(int argc, char **argv) |
| + | { |
| + | const char *opt_max_port = "1024"; /* -P: default max port */ |
| + | const char *opt_min_port = "1"; /* -p: default min port */ |
| + | const char *opt_timeout = "5000"; /* -t: default timeout */ |
| + | /* We estimate rtt and wait rtt*4 before concluding that port is |
| + | * totally blocked. min rtt of 5 ms may be too low if you are |
| + | * scanning an Internet host behind saturated/traffic shaped link. |
| + | * 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 */ |
| + | len_and_sockaddr *lsap; |
| + | int s; |
| + | unsigned port, max_port, nports; |
| + | unsigned closed_ports = 0; |
| + | unsigned open_ports = 0; |
| + | /* all in usec */ |
| + | unsigned timeout; |
| + | unsigned min_rtt; |
| + | unsigned rtt_4; |
| + | unsigned start; |
| + | |
| + | opt_complementary = "=1"; /* exactly one non-option */ |
| + | getopt32(argc, argv, "p: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, 65535); |
| + | nports = max_port - port + 1; |
| + | if ((int)nports <= 0) |
| + | bb_show_usage(); |
| + | 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; |
| + | |
| + | DMSG("min_rtt %u timeout %u", min_rtt, timeout); |
| + | |
| + | lsap = xhost2sockaddr(*argv, port); |
| + | printf("Scanning %s ports %u to %u\n Port\tProto\tState\tService\n", |
| + | *argv, port, max_port); |
| + | |
| + | for (; port <= max_port; port++) { |
| + | DMSG("rtt %u", rtt_4); |
| + | |
| + | /* The SOCK_STREAM socket type is implemented on the TCP/IP protocol. */ |
| + | set_nport(lsap, htons(port)); |
| + | s = xsocket(lsap->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); |
| + | start = gettimeofday_us(); |
| + | if (connect(s, &lsap->sa, lsap->len) == 0) { |
| + | /* Unlikely, for me even localhost fails :) */ |
| + | DMSG("connect succeeded"); |
| + | goto open; |
| + | } |
| + | /* Check for untypical errors... */ |
| + | if (errno != EAGAIN && errno != EINPROGRESS |
| + | && errno != ECONNREFUSED |
| + | ) { |
| + | bb_perror_nomsg_and_die(); |
| + | } |
| + | |
| + | while (1) { |
| + | if (errno == ECONNREFUSED) { |
| + | DMSG("port %u: ECONNREFUSED", port); |
| + | closed_ports++; |
| + | break; |
| + | } |
| + | DERR("port %u errno %d @%u", port, errno, gettimeofday_us() - start); |
| + | if ((gettimeofday_us() - start) > rtt_4) |
| + | break; |
| + | /* Can sleep (much) longer than specified delay. |
| + | * We check rtt BEFORE we usleep, otherwise |
| + | * on localhost we'll do zero writes done (!) |
| + | * before we exceed (rather small) rtt */ |
| + | usleep(rtt_4/8); |
| + | DMSG("write to port %u @%u", port, gettimeofday_us() - start); |
| + | if (write(s, " ", 1) >= 0) { /* We were able to write to the socket */ |
| + | open: |
| + | open_ports++; |
| + | printf("%5u\ttcp\topen\t%s\n", port, port_name(port)); |
| + | break; |
| + | } |
| + | } |
| + | DMSG("out of loop @%u", gettimeofday_us() - start); |
| + | |
| + | /* 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) |
| + | * because we don't want to accidentally miss ports. */ |
| + | rtt_4 = (gettimeofday_us() - start) * 4; |
| + | if (rtt_4 < min_rtt) |
| + | rtt_4 = min_rtt; |
| + | if (rtt_4 > timeout) |
| + | rtt_4 = timeout; |
| + | /* Clean up */ |
| + | close(s); |
| + | } |
| + | if (ENABLE_FEATURE_CLEAN_UP) free(lsap); |
| + | |
| + | printf("%d closed, %d open, %d timed out ports\n", |
| + | closed_ports, |
| + | open_ports, |
| + | nports - (closed_ports + open_ports)); |
| + | return EXIT_SUCCESS; |
| + | } |