/*
** Copyright (C) 2005-2007 by Carnegie Mellon University.
**
** @OPENSOURCE_HEADER_START@
**
** Use of the SILK system and related source code is subject to the terms
** of the following licenses:
**
** GNU Public License (GPL) Rights pursuant to Version 2, June 1991
** Government Purpose License Rights (GPLR) pursuant to DFARS 252.225-7013
**
** NO WARRANTY
**
** ANY INFORMATION, MATERIALS, SERVICES, INTELLECTUAL PROPERTY OR OTHER
** PROPERTY OR RIGHTS GRANTED OR PROVIDED BY CARNEGIE MELLON UNIVERSITY
** PURSUANT TO THIS LICENSE (HEREINAFTER THE "DELIVERABLES") ARE ON AN
** "AS-IS" BASIS. CARNEGIE MELLON UNIVERSITY MAKES NO WARRANTIES OF ANY
** KIND, EITHER EXPRESS OR IMPLIED AS TO ANY MATTER INCLUDING, BUT NOT
** LIMITED TO, WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE,
** MERCHANTABILITY, INFORMATIONAL CONTENT, NONINFRINGEMENT, OR ERROR-FREE
** OPERATION. CARNEGIE MELLON UNIVERSITY SHALL NOT BE LIABLE FOR INDIRECT,
** SPECIAL OR CONSEQUENTIAL DAMAGES, SUCH AS LOSS OF PROFITS OR INABILITY
** TO USE SAID INTELLECTUAL PROPERTY, UNDER THIS LICENSE, REGARDLESS OF
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** CARNEGIE MELLON UNIVERSITY, EXPRESS OR IMPLIED, TO ANY PERSON
** CONCERNING THE APPLICATION OF OR THE RESULTS TO BE OBTAINED WITH THE
** DELIVERABLES UNDER THIS LICENSE.
**
** Licensee hereby agrees to defend, indemnify, and hold harmless Carnegie
** Mellon University, its trustees, officers, employees, and agents from
** all claims or demands made against them (and any related losses,
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** and/or its sub licensees' negligent use or willful misuse of or
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**
** Carnegie Mellon University Software Engineering Institute authored
** documents are sponsored by the U.S. Department of Defense under
** Contract F19628-00-C-0003. Carnegie Mellon University retains
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** reproduce these documents, or allow others to do so, for U.S.
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*/

/*
**
**  rwresolve.c
**
**  Mark Thomas
**  December 2005
**
**      A pipe-line filter to convert an IP to a hostname.  The
**      default field delimiter is '|' in deference to our internal
**      default.  The default fields are 1,2 (numbering starts at 1).
**      Changes can be provided via options --ip-fields=<range> and
**      --delimiter=<char>.
*/

#include "silk.h"

RCSIDENT("$SiLK: rwresolve.c 6081 2007-01-22 19:25:22Z mthomas $");

#include "utils.h"


/* LOCAL DEFINES AND TYPEDEFS */

/* where to send usage output */
#define USAGE_FH stdout

/* max fields (columns) we expect in each line of the output. */
#define MAX_FIELD_COUNT    100

/* set to 1 is use getaddrinfo(3), or to 0 for gethostbyaddr(3) */
#ifndef USE_GET_ADDR_INFO
#  define USE_GET_ADDR_INFO 0
#endif


/* LOCAL FUNCTIONS */

static void appUsageLong(void);              /* never returns */
static void appTeardown(void);
static void appSetup(int argc, char **argv); /* never returns */
static int  appOptionsHandler(clientData cData, int optindex, char *optarg);
static int  parseIPFields(const char *b);


/* LOCAL VARIABLES */

/* a value for each field, where 1 means the field should be resolved;
 * 0 means it should not */
static uint8_t ipFields[MAX_FIELD_COUNT];

/* field delimiter */
static char delimChar;

/* where to send output */
static FILE *outf;


/* OPTIONS SETUP */

typedef enum {
    OPT_IP_FIELDS, OPT_DELIMITER
} appOptionsEnum;


static struct option appOptions[] = {
    {"ip-fields", REQUIRED_ARG, 0, OPT_IP_FIELDS},
    {"delimiter", REQUIRED_ARG, 0, OPT_DELIMITER},
    {0,0,0,0}     /* sentinel entry */
};

static const char *appHelp[] = {
    "IP number fields to resolve (starting at 1). Def. 1,2",
    "delimiter to expect. Def. '|'",
    (char *)NULL
};




/* FUNCTION DEFINITIONS */

/*
 *  appUsageLong();
 *
 *    Print complete usage information to USAGE_FH.  Pass this
 *    function to skOptionsSetUsageCallback(); optionsParse() will
 *    call this funciton and then exit the program when the --help
 *    option is given.
 */
static void appUsageLong(void)
{
#define USAGE_MSG                                                             \
    ("[SWITCHES]\n"                                                           \
     "\tReads delimited text (such as from rwcut) from the standard input\n"  \
     "\tand resolves the IP addresses in the specified columns.  If the\n"    \
     "\t--ip-fields switch is not given, columns 1 and 2 are resolved.\n"     \
     "\tOutput is sent to the standard output.  Beware, this is going\n"      \
     "\tto be slow.\n")

    FILE *fh = USAGE_FH;

    skAppStandardUsage(fh, USAGE_MSG, appOptions, appHelp);
}


/*
 *  appTeardown()
 *
 *    Teardown all modules, close all files, and tidy up all
 *    application state.
 *
 *    This function is idempotent.
 */
static void appTeardown(void)
{
    static int teardownFlag = 0;

    if (teardownFlag) {
        return;
    }
    teardownFlag = 1;

    skAppUnregister();
}


/*
 *  appSetup(argc, argv);
 *
 *    Perform all the setup for this application include setting up
 *    required modules, parsing options, etc.  This function should be
 *    passed the same arguments that were passed into main().
 *
 *    Returns to the caller if all setup succeeds.  If anything fails,
 *    this function will cause the application to exit with a FAILURE
 *    exit status.
 */
static void appSetup(int argc, char **argv)
{
    int arg_index;

    /* verify same number of options and help strings */
    assert((sizeof(appHelp)/sizeof(char *)) ==
           (sizeof(appOptions)/sizeof(struct option)));

    /* register the application */
    skAppRegister(argv[0]);
    skOptionsSetUsageCallback(&appUsageLong);

    /* initialize globals */
    memset(ipFields, sizeof(ipFields), 0);
    ipFields[0] = 1;
    ipFields[1] = 1;
    delimChar = '|';
    outf = stdout;

    /* register the options */
    if (optionsRegister(appOptions, (optHandler)appOptionsHandler, NULL))
    {
        skAppPrintErr("unable to register options");
        exit(EXIT_FAILURE);
    }

    /* parse options */
    arg_index = optionsParse(argc, argv);
    if (arg_index < 0) {
        skAppUsage();             /* never returns */
    }

    /* check for extra arguments */
    if (arg_index != argc) {
        skAppPrintErr("unexpected argument '%s'", argv[arg_index]);
        skAppUsage();             /* never returns */
    }

    if (atexit(appTeardown) < 0) {
        skAppPrintErr("registering appTeardown() failed");
        appTeardown();
        exit(EXIT_FAILURE);
    }

    return;                     /* OK */
}


/*
 *  status = appOptionsHandler(cData, opt_index, opt_arg);
 *
 *    Called by optionsParse(), this handles a user-specified switch
 *    that the application has registered, typically by setting global
 *    variables.  Returns 1 if the switch processing failed or 0 if it
 *    succeeded.  Returning a non-zero from from the handler causes
 *    optionsParse() to return a negative value.
 *
 *    The clientData in 'cData' is typically ignored; 'opt_index' is
 *    the index number that was specified as the last value for each
 *    struct option in appOptions[]; 'opt_arg' is the user's argument
 *    to the switch for options that have a REQUIRED_ARG or an
 *    OPTIONAL_ARG.
 */
static int appOptionsHandler(
    clientData  UNUSED(cData),
    int         opt_index,
    char       *opt_arg)
{
    switch ((appOptionsEnum)opt_index) {
      case OPT_IP_FIELDS:
        /* ip fields */
        if (parseIPFields(opt_arg)) {
            return 1;
        }
        break;

      case OPT_DELIMITER:
        /* delimiter */
        delimChar = *opt_arg;
        if ('\0' == delimChar) {
            skAppPrintErr("empty string not valid argument for --delimiter");
            return 1;
        }
        break;
    }
    return 0;                   /* OK */
}


/*
 * parseIPFields:
 *      given a list (i.e., comma or - delimited set of numbers), set the
 *      element in fields to 1 if the fields are wanted.
 * Input:
 *      char *
 * Return:
 *      0 if OK. 1 else;
 * Side Effects:
 *      fields[]
 */
static int parseIPFields(const char *arg)
{
    uint32_t *list;
    uint32_t count;
    uint32_t i;

    if (skStringParseNumberList(&list, &count, arg, 1, MAX_FIELD_COUNT, 0))
    {
        return 1;
    }

    memset(ipFields, 0, sizeof(ipFields));
    for (i = 0; i < count; ++i) {
        ipFields[list[i] - 1] = 1;
    }

    return 0;                   /* OK */
}


int main(int argc, char **argv)
{
    char line[2048];
    char *cp, *ep, *sp;
    char *eol;
    int field;
    FILE *handle = stdin;
    uint32_t val = 0;
    char *dotted;
#if USE_GET_ADDR_INFO
    struct addrinfo hints;

    /* set up the hints structure */
    memset(&hints, 0, sizeof(struct addrinfo));
    hints.ai_family = AF_INET;
    hints.ai_protocol = IPPROTO_UDP;
    hints.ai_flags = AI_CANONNAME ;
#endif

    appSetup(argc, argv);                       /* never returns */

    /* read from handle until EOF */
    while (!feof(handle)) {
        if (!fgets(line, sizeof(line), handle)) {
            continue;
        }
        eol = strchr(line, '\n');
        if (eol == line) {
            /* empty line; ignore */
            continue;
        }

        if (NULL != eol) {
            /* expected behavior: read an entire line */
            *eol = '\0';
        } else if (feof(handle)) {
            /* okay: last line did not end in newline */
        } else {
            /* bad: line was longer than sizeof(line).  read until newline
             * or eof, then throw away the line */
            while (fgets(line, sizeof(line), handle) && !strchr(line,'\n'))
                ; /* empty */
            continue;
        }

        cp = line;
        field = 0;

        while (*cp) {
            ep = strchr(cp, delimChar);
            if (ep) {
                *ep = '\0';
            }

            if ( !ipFields[field]) {
                /* not an IP field.  Print it. */
                fprintf(outf, "%s", cp);
                goto NEXT_FIELD;
            }

            /* must convert this field */
            sp = cp;

            /* eat leading whitespace */
            while (*sp && isspace((int)*sp)) {
                ++sp;
            }

            dotted = strchr(sp, '.');
            if (dotted == NULL) {
                unsigned long val_ul = strtoul(sp, NULL, 10);
                if (val_ul == 0 || val_ul >= UINT32_MAX) {
                    fprintf(outf, "%s", cp);
                    goto NEXT_FIELD;
                }
                val = (uint32_t)val_ul;
            }

#if USE_GET_ADDR_INFO
            {
                struct addrinfo *addr;
                struct addrinfo *addresses;
                char buf[SK_NUM2DOT_STRLEN];
                int err;

                if (dotted == NULL) {
                    if (NULL == num2dot_r(val, buf)) {
                        fprintf(outf, "%s", cp);
                        goto NEXT_FIELD;
                    }
                    sp = buf;
                }

                err = getaddrinfo(sp, NULL, &hints, &addresses);
                if (err) {
                    fprintf(outf, "%s", cp);
                    goto NEXT_FIELD;
                }

                addr = addresses;
                while (addr) {
                    if (addr->ai_canonname) {
                        fprintf(outf, "%s", addr->ai_canonname);
                        break;
                    }
                    addr = addr->ai_next;
                }
                if (addr == NULL) {
                    /* didn't find a name */
                    fprintf(outf, "%s", cp);
                }
                freeaddrinfo(addresses);
            }
#else
            {
                struct hostent *he;
                in_addr_t a;

                if (dotted) {
                    val = dot2num(sp);
                    if (val == UINT32_MAX) {
                        fprintf(outf, "%s", cp);
                    }
                }

                a = htonl(val);

                he = gethostbyaddr((char*)&a, sizeof(in_addr_t), AF_INET);
                if (he == NULL) {
                    fprintf(outf, "%s", cp);
                    goto NEXT_FIELD;
                } else {
                    fprintf(outf, "%s", he->h_name);
                }
            }
#endif /* USE_GET_ADDR_INFO */

          NEXT_FIELD:
            if (ep) {
                /* we saw a delimiter earlier so print it */
                fprintf(outf, "%c", delimChar);
                cp = ep + 1;
            } else {
                /* at end of line; break out of while() */
                break;
            }
            ++field;
        }

        fprintf(outf, "%s", "\n");

    } /* outer loop over lines  */

    appTeardown();
    exit(EXIT_SUCCESS);
}


/*
** Local variables:
** mode:c
** indent-tabs-mode:nil
** c-basic-offset:4
** End:
*/