forgot svn add...

1 files changed, 150 insertions, 0 deletions

diff --git a/networking/pscan.c b/networking/pscan.c
new file mode 100644
index 000000000..10bf3b606
--- /dev/null
+++ b/networking/pscan.c
@@ -0,0 +1,150 @@
+/*
+ * Pscan is a mini port scanner implementation for busybox
+ *
+ * Copyright 2007 Tito Ragusa <farmatito@tiscali.it>
+ *
+ * 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;
+}