/*

 * lcd_time.c

 *

 * XXX  Should etimelist entries with <0,0> time tuples be timed out?

 * XXX  Need a routine to free the memory?  (Perhaps at shutdown?)

 */

#include <net-snmp/net-snmp-config.h>

#include <net-snmp/net-snmp-features.h>

#include <sys/types.h>

#include <stdio.h>

#ifdef HAVE_STDLIB_H

#include <stdlib.h>

#endif

#ifdef HAVE_STRING_H

#include <string.h>

#else

#include <strings.h>

#endif

#ifdef TIME_WITH_SYS_TIME

# include <sys/time.h>

# include <time.h>

#else

# ifdef HAVE_SYS_TIME_H

#  include <sys/time.h>

# else

#  include <time.h>

# endif

#endif

#ifdef HAVE_NETINET_IN_H

#include <netinet/in.h>

#endif

#ifdef HAVE_UNISTD_H

#include <unistd.h>

#endif

#include <net-snmp/types.h>

#include <net-snmp/output_api.h>

#include <net-snmp/utilities.h>

#include <net-snmp/library/snmp_api.h>

#include <net-snmp/library/callback.h>

#include <net-snmp/library/snmp_secmod.h>

#include <net-snmp/library/snmpusm.h>

#include <net-snmp/library/lcd_time.h>

#include <net-snmp/library/scapi.h>

#include <net-snmp/library/snmpv3.h>

#include <net-snmp/library/transform_oids.h>

netsnmp_feature_child_of(usm_support, libnetsnmp);

netsnmp_feature_child_of(usm_lcd_time, usm_support);

#ifndef NETSNMP_FEATURE_REMOVE_USM_LCD_TIME

/*

 * Global static hashlist to contain Enginetime entries.

 *

 * New records are prepended to the appropriate list at the hash index.

 */

static Enginetime etimelist[ETIMELIST_SIZE];

/*******************************************************************-o-******

 * get_enginetime

 *

 * Parameters:

 *  *engineID

 *   engineID_len

 *  *engineboot

 *  *engine_time

 *      

 * Returns:

 *  SNMPERR_SUCCESS   Success -- when a record for engineID is found.

 *  SNMPERR_GENERR    Otherwise.

 *

 *

 * Lookup engineID and return the recorded values for the

 * <engine_time, engineboot> tuple adjusted to reflect the estimated time

 * at the engine in question.

 *

 * Special case: if engineID is NULL or if engineID_len is 0 then

 * the time tuple is returned immediately as zero.

 *

 * XXX  What if timediff wraps?  >shrug<

 * XXX  Then: you need to increment the boots value.  Now.  Detecting

 *            this is another matter.

 */

int

get_enginetime(const u_char * engineID,

               u_int engineID_len,

               u_int * engineboot,

               u_int * engine_time, u_int authenticated)

{

    int             rval = SNMPERR_SUCCESS;

    int             timediff = 0;

    Enginetime      e = NULL;

    /*

     * Sanity check.

     */

    if (!engine_time || !engineboot) {

        QUITFUN(SNMPERR_GENERR, get_enginetime_quit);

    }

    /*

     * Compute estimated current engine_time tuple at engineID if

     * a record is cached for it.

     */

    *engine_time = *engineboot = 0;

    if (!engineID || (engineID_len <= 0)) {

        QUITFUN(SNMPERR_GENERR, get_enginetime_quit);

    }

    if (!(e = search_enginetime_list(engineID, engineID_len))) {

        QUITFUN(SNMPERR_GENERR, get_enginetime_quit);

    }

#ifdef LCD_TIME_SYNC_OPT

    if (!authenticated || e->authenticatedFlag) {

#endif

        *engine_time = e->engineTime;

        *engineboot = e->engineBoot;

       timediff = (int) (snmpv3_local_snmpEngineTime() - e->lastReceivedEngineTime);

#ifdef LCD_TIME_SYNC_OPT

    }

#endif

    if (timediff > (int) (ENGINETIME_MAX - *engine_time)) {

        *engine_time = (timediff - (ENGINETIME_MAX - *engine_time));

        /*

         * FIX -- move this check up... should not change anything

         * * if engineboot is already locked.  ???

         */

        if (*engineboot < ENGINEBOOT_MAX) {

            *engineboot += 1;

        }

    } else {

        *engine_time += timediff;

    }

    DEBUGMSGTL(("lcd_get_enginetime", "engineID "));

    DEBUGMSGHEX(("lcd_get_enginetime", engineID, engineID_len));

    DEBUGMSG(("lcd_get_enginetime", ": boots=%d, time=%d\n", *engineboot,

              *engine_time));

  get_enginetime_quit:

    return rval;

}                               /* end get_enginetime() */

/*******************************************************************-o-******

 * get_enginetime

 *

 * Parameters:

 *  *engineID

 *   engineID_len

 *  *engineboot

 *  *engine_time

 *      

 * Returns:

 *  SNMPERR_SUCCESS   Success -- when a record for engineID is found.

 *  SNMPERR_GENERR    Otherwise.

 *

 *

 * Lookup engineID and return the recorded values for the

 * <engine_time, engineboot> tuple adjusted to reflect the estimated time

 * at the engine in question.

 *

 * Special case: if engineID is NULL or if engineID_len is 0 then

 * the time tuple is returned immediately as zero.

 *

 * XXX  What if timediff wraps?  >shrug<

 * XXX  Then: you need to increment the boots value.  Now.  Detecting

 *            this is another matter.

 */

int

get_enginetime_ex(u_char * engineID,

                  u_int engineID_len,

                  u_int * engineboot,

                  u_int * engine_time,

                  u_int * last_engine_time, u_int authenticated)

{

    int             rval = SNMPERR_SUCCESS;

    int             timediff = 0;

    Enginetime      e = NULL;

    /*

     * Sanity check.

     */

    if (!engine_time || !engineboot || !last_engine_time) {

        QUITFUN(SNMPERR_GENERR, get_enginetime_ex_quit);

    }

    /*

     * Compute estimated current engine_time tuple at engineID if

     * a record is cached for it.

     */

    *last_engine_time = *engine_time = *engineboot = 0;

    if (!engineID || (engineID_len <= 0)) {

        QUITFUN(SNMPERR_GENERR, get_enginetime_ex_quit);

    }

    if (!(e = search_enginetime_list(engineID, engineID_len))) {

        QUITFUN(SNMPERR_GENERR, get_enginetime_ex_quit);

    }

#ifdef LCD_TIME_SYNC_OPT

    if (!authenticated || e->authenticatedFlag) {

#endif

        *last_engine_time = *engine_time = e->engineTime;

        *engineboot = e->engineBoot;

       timediff = (int) (snmpv3_local_snmpEngineTime() - e->lastReceivedEngineTime);

#ifdef LCD_TIME_SYNC_OPT

    }

#endif

    if (timediff > (int) (ENGINETIME_MAX - *engine_time)) {

        *engine_time = (timediff - (ENGINETIME_MAX - *engine_time));

        /*

         * FIX -- move this check up... should not change anything

         * * if engineboot is already locked.  ???

         */

        if (*engineboot < ENGINEBOOT_MAX) {

            *engineboot += 1;

        }

    } else {

        *engine_time += timediff;

    }

    DEBUGMSGTL(("lcd_get_enginetime_ex", "engineID "));

    DEBUGMSGHEX(("lcd_get_enginetime_ex", engineID, engineID_len));

    DEBUGMSG(("lcd_get_enginetime_ex", ": boots=%d, time=%d\n",

              *engineboot, *engine_time));

  get_enginetime_ex_quit:

    return rval;

}                               /* end get_enginetime_ex() */

void free_enginetime(unsigned char *engineID, size_t engineID_len)

{

    Enginetime      e = NULL, *prev;

    int             rval = 0;

    rval = hash_engineID(engineID, engineID_len);

    if (rval < 0)

  return;

    prev = &etimelist[rval];

    while ((e = *prev) != NULL) {

  if (e->engineID_len == engineID_len &&

      memcmp(e->engineID, engineID, engineID_len) == 0) {

      *prev = e->next;

      SNMP_FREE(e->engineID);

      SNMP_FREE(e);

  } else {

      prev = &e->next;

  }

    }

}

/*******************************************************************-o-****

**

 * free_etimelist

 *

 * Parameters:

 *   None

 *      

 * Returns:

 *   void

 *

 *

 * Free all of the memory used by entries in the etimelist.

 *

 */

void free_etimelist(void)

{

     int index = 0;

     Enginetime e = NULL;

     Enginetime nextE = NULL;

     for( ; index < ETIMELIST_SIZE; ++index)

     {

           e = etimelist[index];

           while(e != NULL)

           {

                 nextE = e->next;

                 SNMP_FREE(e->engineID);

                 SNMP_FREE(e);

                 e = nextE;

           }

           etimelist[index] = NULL;

     }

     return;

}

/*******************************************************************-o-******

 * set_enginetime

 *

 * Parameters:

 *  *engineID

 *   engineID_len

 *   engineboot

 *   engine_time

 *      

 * Returns:

 *  SNMPERR_SUCCESS   Success.

 *  SNMPERR_GENERR    Otherwise.

 *

 *

 * Lookup engineID and store the given <engine_time, engineboot> tuple

 * and then stamp the record with a consistent source of local time.

 * If the engineID record does not exist, create one.

 *

 * Special case: engineID is NULL or engineID_len is 0 defines an engineID

 * that is "always set."

 *

 * XXX  "Current time within the local engine" == time(NULL)...

 */

int

set_enginetime(const u_char * engineID,

               u_int engineID_len,

               u_int engineboot, u_int engine_time, u_int authenticated)

{

    int             rval = SNMPERR_SUCCESS, iindex;

    Enginetime      e = NULL;

    /*

     * Sanity check.

     */

    if (!engineID || (engineID_len <= 0)) {

        return rval;

    }

    /*

     * Store the given <engine_time, engineboot> tuple in the record

     * for engineID.  Create a new record if necessary.

     */

    if (!(e = search_enginetime_list(engineID, engineID_len))) {

        if ((iindex = hash_engineID(engineID, engineID_len)) < 0) {

            QUITFUN(SNMPERR_GENERR, set_enginetime_quit);

        }

        e = calloc(1, sizeof(*e));

        if (!e) {

            QUITFUN(SNMPERR_GENERR, set_enginetime_quit);

        }

        e->engineID = calloc(1, engineID_len);

        if (!e->engineID) {

            QUITFUN(SNMPERR_GENERR, set_enginetime_quit);

        }

        memcpy(e->engineID, engineID, engineID_len);

        e->engineID_len = engineID_len;

        e->next = etimelist[iindex];

        etimelist[iindex] = e;

    }

#ifdef LCD_TIME_SYNC_OPT

    if (authenticated || !e->authenticatedFlag) {

        e->authenticatedFlag = authenticated;

#else

    if (authenticated) {

#endif

        e->engineTime = engine_time;

        e->engineBoot = engineboot;

        e->lastReceivedEngineTime = snmpv3_local_snmpEngineTime();

    }

    e = NULL;                   /* Indicates a successful update. */

    DEBUGMSGTL(("lcd_set_enginetime", "engineID "));

    DEBUGMSGHEX(("lcd_set_enginetime", engineID, engineID_len));

    DEBUGMSG(("lcd_set_enginetime", ": boots=%d, time=%d\n", engineboot,

              engine_time));

  set_enginetime_quit:

    SNMP_FREE(e);

    return rval;

}                               /* end set_enginetime() */

/*******************************************************************-o-******

 * search_enginetime_list

 *

 * Parameters:

 *  *engineID

 *   engineID_len

 *      

 * Returns:

 *  Pointer to a etimelist record with engineID <engineID>  -OR-

 *  NULL if no record exists.

 *

 *

 * Search etimelist for an entry with engineID.

 *

 * ASSUMES that no engineID will have more than one record in the list.

 */

Enginetime

search_enginetime_list(const u_char * engineID, u_int engineID_len)

{

    int             rval = SNMPERR_SUCCESS;

    Enginetime      e = NULL;

    /*

     * Sanity check.

     */

    if (!engineID || (engineID_len <= 0)) {

        QUITFUN(SNMPERR_GENERR, search_enginetime_list_quit);

    }

    /*

     * Find the entry for engineID if there be one.

     */

    rval = hash_engineID(engineID, engineID_len);

    if (rval < 0) {

        QUITFUN(SNMPERR_GENERR, search_enginetime_list_quit);

    }

    e = etimelist[rval];

    for ( /*EMPTY*/; e; e = e->next) {

        if ((engineID_len == e->engineID_len)

            && !memcmp(e->engineID, engineID, engineID_len)) {

            break;

        }

    }

  search_enginetime_list_quit:

    return e;

}                               /* end search_enginetime_list() */

/*******************************************************************-o-******

 * hash_engineID

 *

 * Parameters:

 *  *engineID

 *   engineID_len

 *      

 * Returns:

 *  >0      etimelist index for this engineID.

 *  SNMPERR_GENERR    Error.

 *  

 * 

 * Use a cheap hash to build an index into the etimelist.  Method is 

 * to hash the engineID, then split the hash into u_int's and add them up

 * and modulo the size of the list.

 *

 */

int

hash_engineID(const u_char * engineID, u_int engineID_len)

{

    int             rval = SNMPERR_GENERR;

    size_t          buf_len = SNMP_MAXBUF;

    u_int           additive = 0;

    u_char         *bufp, buf[SNMP_MAXBUF];

    void           *context = NULL;

    /*

     * Sanity check.

     */

    if (!engineID || (engineID_len <= 0)) {

        QUITFUN(SNMPERR_GENERR, hash_engineID_quit);

    }

    /*

     * Hash engineID into a list index.

     */

#ifndef NETSNMP_DISABLE_MD5

    rval = sc_hash(usmHMACMD5AuthProtocol,

                   OID_LENGTH(usmHMACMD5AuthProtocol),

                   engineID, engineID_len, buf, &buf_len);

    if (rval == SNMPERR_SC_NOT_CONFIGURED) {

        /* fall back to sha1 */

        rval = sc_hash(usmHMACSHA1AuthProtocol,

                   OID_LENGTH(usmHMACSHA1AuthProtocol),

                   engineID, engineID_len, buf, &buf_len);

    }

#else

    rval = sc_hash(usmHMACSHA1AuthProtocol,

                   OID_LENGTH(usmHMACSHA1AuthProtocol),

                   engineID, engineID_len, buf, &buf_len);

#endif

    QUITFUN(rval, hash_engineID_quit);

    for (bufp = buf; (bufp - buf) < (int) buf_len; bufp += 4) {

        additive += (u_int) * bufp;

    }

  hash_engineID_quit:

    SNMP_FREE(context);

    memset(buf, 0, SNMP_MAXBUF);

    return (rval < 0) ? rval : (int)(additive % ETIMELIST_SIZE);

}                               /* end hash_engineID() */

#ifdef NETSNMP_ENABLE_TESTING_CODE

/*******************************************************************-o-******

 * dump_etimelist_entry

 *

 * Parameters:

 *  e

 *  count

 */

void

dump_etimelist_entry(Enginetime e, int count)

{

    size_t          buflen;

    char            tabs[SNMP_MAXBUF], *s;

    snprintf(tabs, sizeof(tabs), "%*s", 2 * (count + 1), "");

    buflen = e->engineID_len;

    if (!(s = dump_snmpEngineID(e->engineID, &buflen))) {

        binary_to_hex(e->engineID, e->engineID_len, &s);

    }

    DEBUGMSGTL(("dump_etimelist", "%s\n", tabs));

    DEBUGMSGTL(("dump_etimelist", "%s%s (len=%d) <%d,%d>\n", tabs,

                s, e->engineID_len, e->engineTime, e->engineBoot));

    DEBUGMSGTL(("dump_etimelist", "%s%ld (%ld)", tabs,

                e->lastReceivedEngineTime,

                snmpv3_local_snmpEngineTime() - e->lastReceivedEngineTime));

    SNMP_FREE(s);

}                               /* end dump_etimelist_entry() */

/*******************************************************************-o-******

 * dump_etimelist

 */

void

dump_etimelist(void)

{

    int             iindex = -1, count = 0;

    Enginetime      e;

    DEBUGMSGTL(("dump_etimelist", "\n"));

    while (++iindex < ETIMELIST_SIZE) {

        DEBUGMSG(("dump_etimelist", "[%d]", iindex));

        count = 0;

        e = etimelist[iindex];

        while (e) {

            dump_etimelist_entry(e, count++);

            e = e->next;

        }

        if (count > 0) {

            DEBUGMSG(("dump_etimelist", "\n"));

        }

    }                           /* endwhile */

    DEBUGMSG(("dump_etimelist", "\n"));

}                               /* end dump_etimelist() */

#endif                          /* NETSNMP_ENABLE_TESTING_CODE */

#endif /* NETSNMP_FEATURE_REMOVE_USM_LCD_TIME */