## modules/rp/rp_search.c

/* [<][>][^][v][top][bottom][index][help] */

## FUNCTIONS

This source file includes following functions.

1. rp_exclude_datlink
2. rp_preflist_search
3. rp_find_smallest_span
4. rp_leaf_occ_inc
5. rp_exclude_exact_match
6. rp_find_longest_prefix
7. rp_asc_process_datlist
8. rp_asc_append_datref
9. rp_srch_copyresults
10. rp_begend_preselection
11. RP_asc_search

       1 /***************************************
       2   $Revision: 1.12 $
       3
       4   Radix payload (rp) - user level functions for storing data in radix trees
       5
       6   rp_search = search the loaded radix trees using an ascii key
       7
       8               Motto: "And all that for inetnums..."
       9
      10   Status: NOT REVIEWED, TESTED
      11
      12   Design and implementation by: Marek Bukowy
      13
      14   ******************/ /******************
      15   Copyright (c) 1999                              RIPE NCC
      16
      17   All Rights Reserved
      18
      19   Permission to use, copy, modify, and distribute this software and its
      20   documentation for any purpose and without fee is hereby granted,
      21   provided that the above copyright notice appear in all copies and that
      22   both that copyright notice and this permission notice appear in
      23   supporting documentation, and that the name of the author not be
      24   used in advertising or publicity pertaining to distribution of the
      25   software without specific, written prior permission.
      26
      27   THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
      28   ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS; IN NO EVENT SHALL
      29   AUTHOR BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY
      30   DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
      31   AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
      32   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
      33   ***************************************/
      34
      35
      36 #include <rp.h>
      37
      38 static
      39 void
      40 rp_exclude_datlink(GList    **datlist, GList    *element)
         /* [<][>][^][v][top][bottom][index][help] */
      41 {
      42   /* remove element from list(becomes a self-consistent list) */
      43   *datlist = g_list_remove_link(*datlist, element);
      44
      45   /* free it and the payload */
      46   wr_clear_list( &element );
      47 }
      48
      49
      50 /**************************************************************************/
      51 /*+++++++++++
      52    helper:
      53    this routine goes through the list of prefixes and performs a bin_search
      54    on each of them; attaches the results to datlist.
      55 +++++++++++*/
      56 static
      57 er_ret_t
      58 rp_preflist_search (
         /* [<][>][^][v][top][bottom][index][help] */
      59                     rx_srch_mt search_mode,
      60                     int par_a,
      61                     int par_b,
      62                     rx_tree_t  *mytree,
      63                     GList    **preflist,
      64                     GList    **datlist
      65                     )
      66
      67 {
      68   char   prefstr[IP_PREFSTR_MAX];
      69   GList   *qitem;
      70   ip_prefix_t *querypref;
      71   er_ret_t err;
      72
      73   for( qitem = g_list_first(*preflist);
      74        qitem != NULL;
      75        qitem = g_list_next(qitem)) {
      76
      77     querypref = qitem->data;
      78
      79     if( IP_pref_b2a( querypref, prefstr, IP_PREFSTR_MAX) != IP_OK ) {
      80       die;
      81     }
      82     ER_dbg_va(FAC_RP, ASP_RP_SRCH_DET,
      83               "rx_preflist_search: mode %d (%s) (par %d) for %s",
      84               search_mode, RX_text_srch_mode(search_mode), par_a, prefstr);
      85
      86     if (mytree->num_nodes > 0) {
      87       err = RX_bin_search( search_mode, par_a, par_b, mytree, querypref,
      88                    datlist, RX_ANS_ALL);
      89       if( err != RX_OK ) {
      90         return err;
      91       }
      92     }
      93   }
      94
      95   return RX_OK;
      96 }
      97
      98 /*++++
      99   this is a helper: goes through a datlist and returns the smallest
     100   size of a range
     101
     102   works for IPv4 only
     103   +++*/
     104 static
     105 ip_rangesize_t
     106 rp_find_smallest_span( GList *datlist ) {
         /* [<][>][^][v][top][bottom][index][help] */
     107   ip_rangesize_t  min_span, span;
     108   GList *ditem;
     109
     110   min_span = 0xffffffff; /* IPv4 only!!!!*/
     111
     112     /* go through the list and find the shortest range.    */
     113     for(ditem = g_list_first(datlist);
     114         ditem != NULL;
     115         ditem = g_list_next(ditem)) {
     116       rx_datref_t *refptr = (rx_datref_t *) (ditem->data);
     117
     118       span = IP_rang_span( & refptr->leafptr->iprange);
     119
     120       if( span < min_span ) {
     121         min_span = span;
     122       }
     123     }
     124     ER_dbg_va(FAC_RP, ASP_RP_SRCH_DET,
     125               "rp_find_smallest_span: minimal span is %d", min_span);
     126
     127     return min_span;
     128 }
     129
     130
     131
     132 /* helper for the inetnum/exless search - for this one a hash of pairs
     133 (leafptr,occurences) must be maintained.
     134
     135 This routine increments the counter for a leafptr, creating a new
     136 pair if this leafptr was not referenced before.
     137
     138 */
     139 static
     140 int rp_leaf_occ_inc(GHashTable *hash, rx_dataleaf_t *leafptr)
         /* [<][>][^][v][top][bottom][index][help] */
     141 {
     142   /* one little trick: store the number of occurences
     143      as cast (void *) */
     144   int val;
     145
     146   val = (int) g_hash_table_lookup(hash, leafptr);
     147   /* 0 if it's not known yet. anyway: put it in the hash (value==key) */
     148
     149   g_hash_table_insert(hash, leafptr, (void *) ++val);
     150
     151   return val;
     152 }
     153
     154 /* exclude exact match - not to be merged with preselction :-( */
     155 static void
     156 rp_exclude_exact_match( GList **datlist, ip_range_t *testrang)
         /* [<][>][^][v][top][bottom][index][help] */
     157 {
     158   GList *ditem, *newitem;
     159
     160   ditem = g_list_first(*datlist);
     161
     162   while( ditem != NULL ) {
     163     rx_datref_t *refptr = (rx_datref_t *) (ditem->data);
     164
     165     newitem = g_list_next(ditem);
     166
     167     if( memcmp( & refptr->leafptr->iprange,
     168                 testrang, sizeof(ip_range_t)) == 0 ) {
     169       rp_exclude_datlink(datlist, ditem);
     170       ER_dbg_va(FAC_RP, ASP_RP_SRCH_DET,
     171                 "process_datlist: discarded an exact match");
     172     }
     173     ditem = newitem;
     174   } /* while */
     175 }
     176
     177 static int
     178 rp_find_longest_prefix(GList **datlist)
         /* [<][>][^][v][top][bottom][index][help] */
     179 {
     180   GList *ditem;
     181   int max_pref=0;
     182
     183   for(ditem = g_list_first(*datlist);
     184       ditem != NULL;
     185       ditem = g_list_next(ditem)) {
     186     rx_datref_t *refptr = (rx_datref_t *) (ditem->data);
     187
     188     if( refptr->leafptr->preflen > max_pref ) {
     189       max_pref = refptr->leafptr->preflen;
     190     }
     191   }
     192
     193   return max_pref;
     194 }
     195
     196
     197 /*+ rp_asc_process_datlist() - helper for RP_asc_search()
     198
     199   fetches the copies of objects from the radix tree into datlist
     200
     201      ASSUMES LOCKED TREE
     202
     203      the behaviour for a default inetnum (range) query is:
     204        do an exact match;
     205        if it fails, do an exless match on the encompassing prefix
     206      for routes(prefixes):
     207        do an exless match
     208
     209      So if it's the default search mode on an inetnum tree,
     210      and the key is a range,
     211      then an exact search is performed on one of the composing prefixes.
     212
     213      Then the resulting data leaves are checked for exact matching with
     214      the range queried for.
     215      Any dataleaves that do not match are discarded, and if none are left,
     216      the procedure falls back to searching for the encompassing prefix.
     217      (calculated in the smart_conv routine).
     218      Add the dataleaf copies to the list of answers,
     219      taking span into account
     220 +*/
     221 static
     222 er_ret_t
     223 rp_asc_process_datlist(
         /* [<][>][^][v][top][bottom][index][help] */
     224                        rx_srch_mt search_mode,
     225                        int        par_a,
     226                        rx_fam_t   fam_id,
     227                        int        prefnumber,
     228                        GList    **datlist,
     229                        ip_range_t *testrang,
     230                        int       *hits
     231                        )
     232 {
     233   ip_rangesize_t  min_span=0, span;
     234   int max_pref = -1;
     235   GList    *ditem, *newitem;
     236   GHashTable *lohash = g_hash_table_new(NULL, NULL);
     237
     238   /* in MORE and LESS(1) search exact match must not be displayed */
     239   if ( search_mode == RX_SRCH_MORE
     240        || ( search_mode == RX_SRCH_LESS && par_a == 1 ) ) {
     241     rp_exclude_exact_match(datlist, testrang);
     242   }
     243
     244   /* Preselection moved to processing, only span calculation done here *
     245    *
     246
     247    EXLESS and LESS(1) search: the smallest span must be found,
     248    but if the less spec node is not the same for all composing prefixes,
     249    it means it's not really this one.
     250
     251    we check that by the number of references to this node is less than
     252    the number of composing prefixes
     253
     254    We do the same for the less specific search - a node must be less
     255    specific to all prefixes.
     256
     257    if the number of references is  not enough, then return no hits,
     258    another try will be made, this time with one, encompassing prefix.
     259   */
     260
     261   if ( (search_mode == RX_SRCH_EXLESS )
     262        || ( search_mode == RX_SRCH_LESS && par_a == 1 ) )  {
     263     /* span works only for IP_V4. We use it only for inetnums,
     264        although RT/v4 would work too */
     265     if( testrang->begin.space == IP_V4 &&
     266         fam_id == RX_FAM_IN ) {
     267       min_span = rp_find_smallest_span(*datlist);
     268     }
     269     else {
     270       /* in IPv6 and RT trees in general,  we can obtain the same
     271          result by selecting the longest prefix */
     272       max_pref = rp_find_longest_prefix(datlist);
     273     }
     274   }
     275
     276   /* Process the dataleaf copies and add to the list of answers. */
     277   ditem = g_list_first(*datlist);
     278   while(ditem != NULL) {
     279     rx_datref_t *refptr = (rx_datref_t *) (ditem->data);
     280     int exclude = 0;
     281
     282     if(search_mode == RX_SRCH_EXLESS || search_mode == RX_SRCH_LESS ) {
     283
     284       /* min_span defined <=> EXLESS or LESS(1) search of INETNUMS:
     285          the smallest span must be returned */
     286       if( !exclude && min_span != 0
     287           && (span = IP_rang_span( &refptr->leafptr->iprange))!=min_span) {
     288         ER_dbg_va(FAC_RP, ASP_RP_SRCH_DET,
     289                   "process_datlist: (EX)LESS: discarded object with span %d", span);
     290         exclude = 1;
     291       }
     292       /* max_pref defined <=> EXLESS search of INETNUMS or LESS(1) of RT:
     293        */
     294       if( !exclude && max_pref >= 0
     295           && refptr->leafptr->preflen < max_pref ) {
     296         ER_dbg_va(FAC_RP, ASP_RP_SRCH_DET,
     297                   "process_datlist: (EX)LESS: discarded object with preflen %d",
     298                   refptr->leafptr->preflen);
     299         exclude = 1;
     300       }
     301
     302       /* number of occurences */
     303       /* XXX this will go when the old algorithm goes */
     304       if( !exclude
     305           && prefnumber > 1 ) { /* do not check if all will be approved */
     306
     307         if( rp_leaf_occ_inc(lohash, refptr->leafptr) < prefnumber ) {
     308           ER_dbg_va(FAC_RP, ASP_RP_SRCH_DET,
     309                     "process_datlist: (EX)LESS: leafptr %x not enough",refptr->leafptr);
     310           exclude = 1;
     311         }
     312         else {
     313           ER_dbg_va(FAC_RP, ASP_RP_SRCH_DET,
     314                     "process_datlist: (EX)LESS: leafptr %x GOOD enough",refptr->leafptr);
     315         }
     316       }
     317     }
     318     else if( search_mode ==  RX_SRCH_EXACT ) {
     319       /* EXACT search - discard if the range does not match */
     320       if( memcmp( & refptr->leafptr->iprange,
     321                   testrang, sizeof(ip_range_t)) != 0) {
     322
     323         ER_dbg_va(FAC_RP, ASP_RP_SRCH_DET,
     324                   "process_datlist: EXACT; discarded a mismatch");
     325         exclude = 1;
     326       } /*  EXACT match */
     327     }
     328     else if( search_mode ==  RX_SRCH_MORE ) {
     329       /* MORE: exclude if not fully contained in the search term */
     330       if( ! (IP_addr_in_rang(&refptr->leafptr->iprange.begin, testrang )
     331           && IP_addr_in_rang(&refptr->leafptr->iprange.end, testrang ))) {
     332         ER_dbg_va(FAC_RP, ASP_RP_SRCH_DET,
     333                   "process_datlist: MORE; discarded a not-fully contained one");
     334         exclude = 1;
     335       }
     336     }
     337
     338
     339     /* get next item now, before the current gets deleted */
     340     newitem = g_list_next(ditem);
     341     if( exclude ) {
     342       /* get rid of it */
     343       rp_exclude_datlink(datlist, ditem);
     344     }
     345     else {
     346       /* OK, so we ACCEPT these results*/
     347       /* uniqueness ensured in copy_results */
     348       (*hits)++;
     349     }
     350     ditem = newitem;
     351   } /* while ditem */
     352
     353   /* wr_clear_list(&lolist); */
     354   g_hash_table_destroy(lohash);
     355   return RX_OK;
     356 }
     357
     358 /**************************************************************************/
     359
     360 /*+ appends the element pointed to by datref to finallist +*/
     361 static
     362 er_ret_t
     363 rp_asc_append_datref(rx_datref_t *refptr, GList **finallist)
         /* [<][>][^][v][top][bottom][index][help] */
     364 {
     365   er_ret_t err;
     366   rx_datcpy_t *datcpy;
     367   void *dataptr;
     368
     369     /* OK, so we ACCEPT this result. Copy it.*/
     370
     371     if( (err=wr_calloc( (void **)& datcpy, 1, sizeof(rx_datcpy_t))) != UT_OK) {
     372       return err; /*    die;*/
     373     }
     374
     375     datcpy->leafcpy = *(refptr->leafptr);
     376
     377     /* copy the immediate data too. Set the ptr.*/
     378
     379     if( (err=wr_calloc( (void **) & dataptr, 1, refptr->leafptr->data_len))
     380         != UT_OK) {
     381       return err; /*    die;*/
     382     }
     383     memcpy(dataptr, refptr->leafptr->data_ptr, refptr->leafptr->data_len);
     384
     385     datcpy->leafcpy.data_ptr = dataptr;
     386
     387     *finallist = g_list_prepend(*finallist, datcpy);
     388
     389     /* XXX this wouldn't work in access_control */
     390     ER_dbg_va(FAC_RP, ASP_RP_SRCH_DATA,
     391               "rp_asc_append 'ed: %s", dataptr);
     392
     393     return RX_OK;
     394 }
     395
     396 /*+ goes through datlist (list of references "datref") and add copies of
     397 leaves referenced to the finallist
     398
     399 maintains its own uniqhash which holds pointers to copied dataleaves.
     400
     401 modifies: finallist
     402
     403 returns: error from wr_malloc
     404
     405 +*/
     406 static
     407 er_ret_t
     408 rp_srch_copyresults(GList *datlist,
         /* [<][>][^][v][top][bottom][index][help] */
     409                     GList **finallist,
     410                     int maxcount)
     411 {
     412   er_ret_t err;
     413   GList    *ditem;
     414   GHashTable *uniqhash = g_hash_table_new(NULL, NULL); /* defaults */
     415   int count = 0;
     416
     417   ER_dbg_va(FAC_RP, ASP_RP_SRCH_DET, "srch_copyresults");
     418
     419   /*  copy dataleaves pointed to by entries from the datlist
     420       only once (check uniqueness in the hash table) */
     421   for(ditem = g_list_first(datlist);
     422       ditem != NULL;
     423       ditem = g_list_next(ditem)) {
     424     rx_datref_t   *refptr = (rx_datref_t *) (ditem->data);
     425     rx_dataleaf_t *ansptr = refptr->leafptr;
     426
     427     /* search for every ansptr (dataleaf pointer) in uniqhash */
     428     if( g_hash_table_lookup(uniqhash, ansptr) == NULL ) {
     429
     430       /* it's not known yet. OK: put it in the hash (value==key) */
     431       g_hash_table_insert(uniqhash, ansptr, ansptr);
     432
     433       /* and copy the dataleaf */
     434       if( !NOERR(err = rp_asc_append_datref(refptr, finallist)) ) {
     435         return err;
     436       }
     437     }
     438
     439     /* check the limit on number of objects if defined ( >0)  */
     440     count++;
     441     if( maxcount > 0 && count > maxcount ) {
     442       break;
     443     }
     444
     445   } /*  foreach (datlist) */
     446
     447   g_hash_table_destroy(uniqhash); /* elements are still linked to through datlist */
     448
     449   return RP_OK;
     450 }
     451
     452 static
     453 void
     454 rp_begend_preselection(GList **datlist, rx_fam_t fam_id, ip_range_t *testrang)
         /* [<][>][^][v][top][bottom][index][help] */
     455 {
     456   GList *ditem, *newitem;
     457
     458   ditem = g_list_first(*datlist);
     459
     460   while( ditem != NULL ) {
     461     rx_datref_t *refptr = (rx_datref_t *) (ditem->data);
     462     newitem = g_list_next(ditem);
     463
     464     /* the test is indentical for route & inetnum trees */
     465     if( IP_addr_in_rang(&testrang->end, &refptr->leafptr->iprange) == 0 ) {
     466
     467       rp_exclude_datlink(datlist, ditem);
     468       ER_dbg_va(FAC_RP, ASP_RP_SRCH_DET,
     469                 "process_datlist: discarded an uncovering leafptr %x",
     470                 refptr->leafptr);
     471
     472     }
     473     ditem = newitem;
     474   } /* while */
     475 }
     476
     477 /*+++++++++++++++
     478   search.
     479
     480   2 approaches:
     481
     482   1. (most modes): look up all less specifics of beginning and end of range,
     483   compare/select/etc.
     484
     485   2. More spec mode: break up the query range into prefixes, [erform a search
     486   for each of them. Add all results together.
     487
     488   translates a query into a binary prefix (or prefixes, if range).
     489   for registry+space (or if they are zero, for all
     490   registries/spaces)
     491   finds tree
     492   calls RX_bin_search (returning node copies).
     493   will not put duplicate entries (composed inetnums).
     494   returns some sort of error code :-)
     495
     496   Cuts the number of answers from RX_bin_search down to max_count,
     497   but since some of the answers may have been "normalized" in the
     498   underlying functions (multiple occurences removed),
     499   the result is _at_most_ max_count.
     500
     501   appends to a given list of data blocks (not nodes!)
     502
     503   The EXLESS search on inetnum tree should return the shortest range
     504   that was found, by means of comparing span (size) of the range.
     505   If there are more of size equal to the smallest one, they are also
     506   returned.
     507
     508   returns RX_OK or a code from an underlying function
     509 ++++++++++++*/
     510 er_ret_t
     511 RP_asc_search (
         /* [<][>][^][v][top][bottom][index][help] */
     512                rx_srch_mt search_mode,
     513                int par_a,
     514                int par_b,
     515                char *key,     /*+ search term: (string) prefix/range/IP +*/
     516                rp_regid_t  reg_id,
     517                rp_attr_t  attr,    /*+ extra tree id (within the same reg/spc/fam +*/
     518                GList **finallist,    /*+ answers go here, please +*/
     519                int    max_count    /*+ max # of answers. RX_ALLANS == unlimited +*/
     520                )
     521 {
     522   GList    *preflist = NULL;
     523   GList    *datlist = NULL;
     524   er_ret_t   err;
     525   ip_range_t  testrang;
     526   int        locked = 0;
     527   ip_keytype_t key_type;
     528   ip_space_t   spc_id;
     529   rx_fam_t   fam_id = RP_attr2fam( attr );
     530   rx_tree_t   *mytree;
     531   int hits=0;
     532   ip_prefix_t beginpref;
     533
     534
     535   /*  abort on error (but unlock the tree) */
     536   ER_dbg_va(FAC_RP, ASP_RP_SRCH_GEN,
     537             "RP_NEW_asc_search:  query %s : mode %d (%s) (par %d) for %s",
     538             DF_get_attribute_name(attr),
     539             search_mode, RX_text_srch_mode(search_mode), par_a, key);
     540
     541
     542   /* parse the key into a prefix list */
     543   if( ( err = IP_smart_conv(key, 0, 0,
     544                             &preflist, IP_EXPN, &key_type)) != IP_OK ) {
     545     /* operational trouble (UT_*) or invalid key (IP_INVARG)*/
     546     return err;
     547   }
     548
     549   /* set the test values */
     550   IP_smart_range(key, &testrang, IP_EXPN, &key_type);
     551
     552   /* find the tree */
     553   if( NOERR(err) ) {
     554     spc_id = IP_pref_b2_space( g_list_first(preflist)->data );
     555     if( ! NOERR(err = RP_tree_get( &mytree, reg_id, spc_id, attr ))) {
     556       return err;
     557     }
     558   }
     559   /* the point of no return: now we lock the tree. From here, even if errors
     560      occur, we still go through all procedure to unlock the tree at the end */
     561
     562   /* lock the tree */
     563   TH_acquire_read_lock( &(mytree->rwlock) );
     564   locked = 1;
     565
     566   /* Collection: this procedure is used for some search_modes only */
     567   if(    search_mode == RX_SRCH_EXLESS
     568       || search_mode == RX_SRCH_LESS
     569       || search_mode == RX_SRCH_EXACT )  {
     570
     571     /* 1. compose a /32(/128) prefix for beginning of range */
     572     beginpref.ip = testrang.begin;
     573     beginpref.bits = IP_sizebits(spc_id);
     574
     575     /* 2. dataleaves collection: look up the beginning prefix in LESS(255) mode */
     576     if( NOERR(err) ) {
     577       err = RX_bin_search( RX_SRCH_LESS, 255, 0, mytree, &beginpref,
     578                            &datlist, RX_ANS_ALL);
     579     }
     580
     581     /* 3. preselection: exclude those that do not include end of range
     582      */
     583     if( NOERR(err) ) {
     584       rp_begend_preselection(&datlist, fam_id, &testrang);
     585     }
     586
     587   } /* if exless|less|exact */
     588   else {
     589     /* MORE */
     590
     591     /* standard collection using the traditional method:
     592        repeat the search for all prefixes and join results */
     593
     594     if( NOERR(err) ) {
     595       err = rp_preflist_search ( search_mode, par_a, par_b,
     596                                  mytree, &preflist, &datlist);
     597     }
     598   } /* collection */
     599
     600   ER_dbg_va(FAC_RP, ASP_RP_SRCH_GEN,
     601             "RP_NEW_asc_search: collected %d references ",
     602             g_list_length(datlist));
     603
     604
     605   /* 5. processing - using the same processing function */
     606   if( NOERR(err) ) {
     607     err = rp_asc_process_datlist( search_mode, par_a, fam_id,
     608                                   1, /* one occurence is enough */
     609                                   &datlist,
     610                                   &testrang,  &hits );
     611   }
     612
     613   /* 6. copy results */
     614   if( NOERR(err) ) {
     615     err = rp_srch_copyresults(datlist, finallist, max_count); /* and uniq */
     616   }
     617
     618   if( locked ) {
     619     /* 100. unlock the tree */
     620     TH_release_read_lock( &(mytree->rwlock) );
     621   }
     622
     623   /* clean up */
     624   wr_clear_list( &preflist );
     625   wr_clear_list( &datlist );
     626
     627   /* NOTE if error occured, finallist may be partly filled in. */
     628   return err;
     629 }
     630

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