## 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: 1.15 $
       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 use_span = 0;
     235   int max_pref = -1;
     236   GList    *ditem, *newitem;
     237   GHashTable *lohash = g_hash_table_new(NULL, NULL);
     238
     239   /* in MORE and LESS(1) search exact match must not be displayed */
     240   if ( search_mode == RX_SRCH_MORE
     241        || ( search_mode == RX_SRCH_LESS && par_a == 1 ) ) {
     242     rp_exclude_exact_match(datlist, testrang);
     243   }
     244
     245   /* Preselection moved to processing, only span calculation done here *
     246    *
     247
     248    EXLESS and LESS(1) search: the smallest span must be found,
     249    but if the less spec node is not the same for all composing prefixes,
     250    it means it's not really this one.
     251
     252    we check that by the number of references to this node is less than
     253    the number of composing prefixes
     254
     255    We do the same for the less specific search - a node must be less
     256    specific to all prefixes.
     257
     258    if the number of references is  not enough, then return no hits,
     259    another try will be made, this time with one, encompassing prefix.
     260   */
     261
     262   if ( (search_mode == RX_SRCH_EXLESS )
     263        || ( search_mode == RX_SRCH_LESS && par_a == 1 ) )  {
     264     /* span works only for IP_V4. We use it only for inetnums,
     265        although RT/v4 would work too */
     266     if( testrang->begin.space == IP_V4 &&
     267         fam_id == RX_FAM_IN ) {
     268       min_span = rp_find_smallest_span(*datlist);
     269       use_span = 1;
     270     }
     271     else {
     272       /* in IPv6 and RT trees in general,  we can obtain the same
     273          result by selecting the longest prefix */
     274       max_pref = rp_find_longest_prefix(datlist);
     275     }
     276   }
     277
     278   /* Process the dataleaf copies and add to the list of answers. */
     279   ditem = g_list_first(*datlist);
     280   while(ditem != NULL) {
     281     rx_datref_t *refptr = (rx_datref_t *) (ditem->data);
     282     int exclude = 0;
     283
     284     if(search_mode == RX_SRCH_EXLESS || search_mode == RX_SRCH_LESS ) {
     285
     286       /* min_span defined <=> EXLESS or LESS(1) search of INETNUMS:
     287          the smallest span must be returned */
     288       if( !exclude && use_span
     289           && (span = IP_rang_span( &refptr->leafptr->iprange))!=min_span) {
     290         ER_dbg_va(FAC_RP, ASP_RP_SRCH_DET,
     291                   "process_datlist: (EX)LESS: discarded object with span %d", span);
     292         exclude = 1;
     293       }
     294       /* max_pref defined <=> EXLESS search of INETNUMS or LESS(1) of RT:
     295        */
     296       if( !exclude && max_pref >= 0
     297           && refptr->leafptr->preflen < max_pref ) {
     298         ER_dbg_va(FAC_RP, ASP_RP_SRCH_DET,
     299                   "process_datlist: (EX)LESS: discarded object with preflen %d",
     300                   refptr->leafptr->preflen);
     301         exclude = 1;
     302       }
     303
     304       /* number of occurences */
     305       /* XXX this will go when the old algorithm goes */
     306       if( !exclude
     307           && prefnumber > 1 ) { /* do not check if all will be approved */
     308
     309         if( rp_leaf_occ_inc(lohash, refptr->leafptr) < prefnumber ) {
     310           ER_dbg_va(FAC_RP, ASP_RP_SRCH_DET,
     311                     "process_datlist: (EX)LESS: leafptr %x not enough",refptr->leafptr);
     312           exclude = 1;
     313         }
     314         else {
     315           ER_dbg_va(FAC_RP, ASP_RP_SRCH_DET,
     316                     "process_datlist: (EX)LESS: leafptr %x GOOD enough",refptr->leafptr);
     317         }
     318       }
     319     }
     320     else if( search_mode ==  RX_SRCH_EXACT ) {
     321       /* EXACT search - discard if the range does not match */
     322       if( memcmp( & refptr->leafptr->iprange,
     323                   testrang, sizeof(ip_range_t)) != 0) {
     324
     325         ER_dbg_va(FAC_RP, ASP_RP_SRCH_DET,
     326                   "process_datlist: EXACT; discarded a mismatch");
     327         exclude = 1;
     328       } /*  EXACT match */
     329     }
     330     else if( search_mode ==  RX_SRCH_MORE ) {
     331       /* MORE: exclude if not fully contained in the search term */
     332       if( ! (IP_addr_in_rang(&refptr->leafptr->iprange.begin, testrang )
     333           && IP_addr_in_rang(&refptr->leafptr->iprange.end, testrang ))) {
     334         ER_dbg_va(FAC_RP, ASP_RP_SRCH_DET,
     335                   "process_datlist: MORE; discarded a not-fully contained one");
     336         exclude = 1;
     337       }
     338     }
     339
     340
     341     /* get next item now, before the current gets deleted */
     342     newitem = g_list_next(ditem);
     343     if( exclude ) {
     344       /* get rid of it */
     345       rp_exclude_datlink(datlist, ditem);
     346     }
     347     else {
     348       /* OK, so we ACCEPT these results*/
     349       /* uniqueness ensured in copy_results */
     350       (*hits)++;
     351     }
     352     ditem = newitem;
     353   } /* while ditem */
     354
     355   /* wr_clear_list(&lolist); */
     356   g_hash_table_destroy(lohash);
     357   return RX_OK;
     358 }
     359
     360 /**************************************************************************/
     361
     362 /*+ appends the element pointed to by datref to finallist +*/
     363 static
     364 er_ret_t
     365 rp_asc_append_datref(rx_datref_t *refptr, GList **finallist)
         /* [<][>][^][v][top][bottom][index][help] */
     366 {
     367   er_ret_t err;
     368   rx_datcpy_t *datcpy;
     369   void *dataptr;
     370
     371     /* OK, so we ACCEPT this result. Copy it.*/
     372
     373     if( (err=wr_calloc( (void **)& datcpy, 1, sizeof(rx_datcpy_t))) != UT_OK) {
     374       return err; /*    die;*/
     375     }
     376
     377     datcpy->leafcpy = *(refptr->leafptr);
     378
     379     /* copy the immediate data too. Set the ptr.*/
     380
     381     if( (err=wr_calloc( (void **) & dataptr, 1, refptr->leafptr->data_len))
     382         != UT_OK) {
     383       return err; /*    die;*/
     384     }
     385     memcpy(dataptr, refptr->leafptr->data_ptr, refptr->leafptr->data_len);
     386
     387     datcpy->leafcpy.data_ptr = dataptr;
     388
     389     *finallist = g_list_prepend(*finallist, datcpy);
     390
     391     /* XXX this wouldn't work in access_control */
     392     ER_dbg_va(FAC_RP, ASP_RP_SRCH_DATA,
     393               "rp_asc_append 'ed: %s", dataptr);
     394
     395     return RX_OK;
     396 }
     397
     398 /*+ goes through datlist (list of references "datref") and add copies of
     399 leaves referenced to the finallist
     400
     401 maintains its own uniqhash which holds pointers to copied dataleaves.
     402
     403 modifies: finallist
     404
     405 returns: error from wr_malloc
     406
     407 +*/
     408 static
     409 er_ret_t
     410 rp_srch_copyresults(GList *datlist,
         /* [<][>][^][v][top][bottom][index][help] */
     411                     GList **finallist,
     412                     int maxcount)
     413 {
     414   er_ret_t err;
     415   GList    *ditem;
     416   GHashTable *uniqhash = g_hash_table_new(NULL, NULL); /* defaults */
     417   int count = 0;
     418
     419   ER_dbg_va(FAC_RP, ASP_RP_SRCH_DET, "srch_copyresults");
     420
     421   /*  copy dataleaves pointed to by entries from the datlist
     422       only once (check uniqueness in the hash table) */
     423   for(ditem = g_list_first(datlist);
     424       ditem != NULL;
     425       ditem = g_list_next(ditem)) {
     426     rx_datref_t   *refptr = (rx_datref_t *) (ditem->data);
     427     rx_dataleaf_t *ansptr = refptr->leafptr;
     428
     429     /* search for every ansptr (dataleaf pointer) in uniqhash */
     430     if( g_hash_table_lookup(uniqhash, ansptr) == NULL ) {
     431
     432       /* it's not known yet. OK: put it in the hash (value==key) */
     433       g_hash_table_insert(uniqhash, ansptr, ansptr);
     434
     435       /* and copy the dataleaf */
     436       if( !NOERR(err = rp_asc_append_datref(refptr, finallist)) ) {
     437         return err;
     438       }
     439     }
     440
     441     /* check the limit on number of objects if defined ( >0)  */
     442     count++;
     443     if( maxcount > 0 && count > maxcount ) {
     444       break;
     445     }
     446
     447   } /*  foreach (datlist) */
     448
     449   g_hash_table_destroy(uniqhash); /* elements are still linked to through datlist */
     450
     451   return RP_OK;
     452 }
     453
     454 static
     455 void
     456 rp_begend_preselection(GList **datlist, rx_fam_t fam_id, ip_range_t *testrang)
         /* [<][>][^][v][top][bottom][index][help] */
     457 {
     458   GList *ditem, *newitem;
     459
     460   ditem = g_list_first(*datlist);
     461
     462   while( ditem != NULL ) {
     463     rx_datref_t *refptr = (rx_datref_t *) (ditem->data);
     464     newitem = g_list_next(ditem);
     465
     466     /* the test is indentical for route & inetnum trees */
     467     if( IP_addr_in_rang(&testrang->end, &refptr->leafptr->iprange) == 0 ) {
     468
     469       ER_dbg_va(FAC_RP, ASP_RP_SRCH_DET,
     470                 "process_datlist: discarded an uncovering leafptr %x",
     471                 refptr->leafptr);
     472       rp_exclude_datlink(datlist, ditem);
     473     }
     474     ditem = newitem;
     475   } /* while */
     476 }
     477
     478 /*+++++++++++++++
     479   search.
     480
     481   2 approaches:
     482
     483   1. (most modes): look up all less specifics of beginning and end of range,
     484   compare/select/etc.
     485
     486   2. More spec mode: break up the query range into prefixes, [erform a search
     487   for each of them. Add all results together.
     488
     489   translates a query into a binary prefix (or prefixes, if range).
     490   for registry+space (or if they are zero, for all
     491   registries/spaces)
     492   finds tree
     493   calls RX_bin_search (returning node copies).
     494   will not put duplicate entries (composed inetnums).
     495   returns some sort of error code :-)
     496
     497   Cuts the number of answers from RX_bin_search down to max_count,
     498   but since some of the answers may have been "normalized" in the
     499   underlying functions (multiple occurences removed),
     500   the result is _at_most_ max_count.
     501
     502   appends to a given list of data blocks (not nodes!)
     503
     504   The EXLESS search on inetnum tree should return the shortest range
     505   that was found, by means of comparing span (size) of the range.
     506   If there are more of size equal to the smallest one, they are also
     507   returned.
     508
     509   returns RX_OK or a code from an underlying function
     510 ++++++++++++*/
     511 er_ret_t
     512 RP_asc_search (
         /* [<][>][^][v][top][bottom][index][help] */
     513                rx_srch_mt search_mode,
     514                int par_a,
     515                int par_b,
     516                char *key,     /*+ search term: (string) prefix/range/IP +*/
     517                rp_regid_t  reg_id,
     518                rp_attr_t  attr,    /*+ extra tree id (within the same reg/spc/fam +*/
     519                GList **finallist,    /*+ answers go here, please +*/
     520                int    max_count    /*+ max # of answers. RX_ALLANS == unlimited +*/
     521                )
     522 {
     523   GList    *preflist = NULL;
     524   GList    *datlist = NULL;
     525   er_ret_t   err;
     526   ip_range_t  testrang;
     527   int        locked = 0;
     528   ip_keytype_t key_type;
     529   ip_space_t   spc_id;
     530   rx_fam_t   fam_id = RP_attr2fam( attr );
     531   rx_tree_t   *mytree;
     532   int hits=0;
     533   ip_prefix_t beginpref;
     534
     535
     536   /*  abort on error (but unlock the tree) */
     537   ER_dbg_va(FAC_RP, ASP_RP_SRCH_GEN,
     538             "RP_NEW_asc_search:  query %s : mode %d (%s) (par %d) for %s",
     539             DF_get_attribute_name(attr),
     540             search_mode, RX_text_srch_mode(search_mode), par_a, key);
     541
     542
     543   /* parse the key into a prefix list */
     544   if( ( err = IP_smart_conv(key, 0, 0,
     545                             &preflist, IP_EXPN, &key_type)) != IP_OK ) {
     546     /* operational trouble (UT_*) or invalid key (IP_INVARG)*/
     547     return err;
     548   }
     549
     550   /* set the test values */
     551   IP_smart_range(key, &testrang, IP_EXPN, &key_type);
     552
     553   /* find the tree */
     554   if( NOERR(err) ) {
     555     spc_id = IP_pref_b2_space( g_list_first(preflist)->data );
     556     if( ! NOERR(err = RP_tree_get( &mytree, reg_id, spc_id, attr ))) {
     557       return err;
     558     }
     559   }
     560   /* the point of no return: now we lock the tree. From here, even if errors
     561      occur, we still go through all procedure to unlock the tree at the end */
     562
     563   /* lock the tree */
     564   TH_acquire_read_lockw( &(mytree->rwlock) );
     565   locked = 1;
     566
     567   /* Collection: this procedure is used for some search_modes only */
     568   if(    search_mode == RX_SRCH_EXLESS
     569       || search_mode == RX_SRCH_LESS
     570       || search_mode == RX_SRCH_EXACT )  {
     571
     572     /* 1. compose a /32(/128) prefix for beginning of range */
     573     beginpref.ip = testrang.begin;
     574     beginpref.bits = IP_sizebits(spc_id);
     575
     576     /* 2. dataleaves collection: look up the beginning prefix in LESS(255) mode */
     577     if( NOERR(err) ) {
     578       err = RX_bin_search( RX_SRCH_LESS, 255, 0, mytree, &beginpref,
     579                            &datlist, RX_ANS_ALL);
     580     }
     581
     582     /* 3. preselection: exclude those that do not include end of range
     583      */
     584     if( NOERR(err) ) {
     585       rp_begend_preselection(&datlist, fam_id, &testrang);
     586     }
     587
     588   } /* if exless|less|exact */
     589   else {
     590     /* MORE */
     591
     592     /* standard collection using the traditional method:
     593        repeat the search for all prefixes and join results */
     594
     595     if( NOERR(err) ) {
     596       err = rp_preflist_search ( search_mode, par_a, par_b,
     597                                  mytree, &preflist, &datlist);
     598     }
     599   } /* collection */
     600
     601   ER_dbg_va(FAC_RP, ASP_RP_SRCH_GEN,
     602             "RP_NEW_asc_search: collected %d references ",
     603             g_list_length(datlist));
     604
     605
     606   /* 5. processing - using the same processing function */
     607   if( NOERR(err) ) {
     608     err = rp_asc_process_datlist( search_mode, par_a, fam_id,
     609                                   1, /* one occurence is enough */
     610                                   &datlist,
     611                                   &testrang,  &hits );
     612   }
     613
     614   /* 6. copy results */
     615   if( NOERR(err) ) {
     616     err = rp_srch_copyresults(datlist, finallist, max_count); /* and uniq */
     617   }
     618
     619   if( locked ) {
     620     /* 100. unlock the tree */
     621     TH_release_read_lockw( &(mytree->rwlock) );
     622   }
     623
     624   /* clean up */
     625   wr_clear_list( &preflist );
     626   wr_clear_list( &datlist );
     627
     628   /* NOTE if error occured, finallist may be partly filled in. */
     629   return err;
     630 }
     631

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