The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/net/radix.c

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    1 /*-
    2  * Copyright (c) 1988, 1989, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  * 4. Neither the name of the University nor the names of its contributors
   14  *    may be used to endorse or promote products derived from this software
   15  *    without specific prior written permission.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  *
   29  *      @(#)radix.c     8.5 (Berkeley) 5/19/95
   30  * $FreeBSD$
   31  */
   32 
   33 /*
   34  * Routines to build and maintain radix trees for routing lookups.
   35  */
   36 #ifndef _RADIX_H_
   37 #include <sys/param.h>
   38 #ifdef  _KERNEL
   39 #include <sys/lock.h>
   40 #include <sys/mutex.h>
   41 #include <sys/systm.h>
   42 #include <sys/malloc.h>
   43 #include <sys/domain.h>
   44 #else
   45 #include <stdlib.h>
   46 #endif
   47 #include <sys/syslog.h>
   48 #include <net/radix.h>
   49 #endif
   50 
   51 static int      rn_walktree_from(struct radix_node_head *h, void *a, void *m,
   52                     walktree_f_t *f, void *w);
   53 static int rn_walktree(struct radix_node_head *, walktree_f_t *, void *);
   54 static struct radix_node
   55          *rn_insert(void *, struct radix_node_head *, int *,
   56              struct radix_node [2]),
   57          *rn_newpair(void *, int, struct radix_node[2]),
   58          *rn_search(void *, struct radix_node *),
   59          *rn_search_m(void *, struct radix_node *, void *);
   60 
   61 static int      max_keylen;
   62 static struct radix_mask *rn_mkfreelist;
   63 static struct radix_node_head *mask_rnhead;
   64 /*
   65  * Work area -- the following point to 3 buffers of size max_keylen,
   66  * allocated in this order in a block of memory malloc'ed by rn_init.
   67  */
   68 static char *rn_zeros, *rn_ones, *addmask_key;
   69 
   70 #define MKGet(m) {                                              \
   71         if (rn_mkfreelist) {                                    \
   72                 m = rn_mkfreelist;                              \
   73                 rn_mkfreelist = (m)->rm_mklist;                 \
   74         } else                                                  \
   75                 R_Malloc(m, struct radix_mask *, sizeof (struct radix_mask)); }
   76  
   77 #define MKFree(m) { (m)->rm_mklist = rn_mkfreelist; rn_mkfreelist = (m);}
   78 
   79 #define rn_masktop (mask_rnhead->rnh_treetop)
   80 
   81 static int      rn_lexobetter(void *m_arg, void *n_arg);
   82 static struct radix_mask *
   83                 rn_new_radix_mask(struct radix_node *tt,
   84                     struct radix_mask *next);
   85 static int      rn_satisfies_leaf(char *trial, struct radix_node *leaf,
   86                     int skip);
   87 
   88 /*
   89  * The data structure for the keys is a radix tree with one way
   90  * branching removed.  The index rn_bit at an internal node n represents a bit
   91  * position to be tested.  The tree is arranged so that all descendants
   92  * of a node n have keys whose bits all agree up to position rn_bit - 1.
   93  * (We say the index of n is rn_bit.)
   94  *
   95  * There is at least one descendant which has a one bit at position rn_bit,
   96  * and at least one with a zero there.
   97  *
   98  * A route is determined by a pair of key and mask.  We require that the
   99  * bit-wise logical and of the key and mask to be the key.
  100  * We define the index of a route to associated with the mask to be
  101  * the first bit number in the mask where 0 occurs (with bit number 0
  102  * representing the highest order bit).
  103  *
  104  * We say a mask is normal if every bit is 0, past the index of the mask.
  105  * If a node n has a descendant (k, m) with index(m) == index(n) == rn_bit,
  106  * and m is a normal mask, then the route applies to every descendant of n.
  107  * If the index(m) < rn_bit, this implies the trailing last few bits of k
  108  * before bit b are all 0, (and hence consequently true of every descendant
  109  * of n), so the route applies to all descendants of the node as well.
  110  *
  111  * Similar logic shows that a non-normal mask m such that
  112  * index(m) <= index(n) could potentially apply to many children of n.
  113  * Thus, for each non-host route, we attach its mask to a list at an internal
  114  * node as high in the tree as we can go.
  115  *
  116  * The present version of the code makes use of normal routes in short-
  117  * circuiting an explict mask and compare operation when testing whether
  118  * a key satisfies a normal route, and also in remembering the unique leaf
  119  * that governs a subtree.
  120  */
  121 
  122 /*
  123  * Most of the functions in this code assume that the key/mask arguments
  124  * are sockaddr-like structures, where the first byte is an u_char
  125  * indicating the size of the entire structure.
  126  *
  127  * To make the assumption more explicit, we use the LEN() macro to access
  128  * this field. It is safe to pass an expression with side effects
  129  * to LEN() as the argument is evaluated only once.
  130  */
  131 #define LEN(x) (*(const u_char *)(x))
  132 
  133 /*
  134  * XXX THIS NEEDS TO BE FIXED
  135  * In the code, pointers to keys and masks are passed as either
  136  * 'void *' (because callers use to pass pointers of various kinds), or
  137  * 'caddr_t' (which is fine for pointer arithmetics, but not very
  138  * clean when you dereference it to access data). Furthermore, caddr_t
  139  * is really 'char *', while the natural type to operate on keys and
  140  * masks would be 'u_char'. This mismatch require a lot of casts and
  141  * intermediate variables to adapt types that clutter the code.
  142  */
  143 
  144 /*
  145  * Search a node in the tree matching the key.
  146  */
  147 static struct radix_node *
  148 rn_search(v_arg, head)
  149         void *v_arg;
  150         struct radix_node *head;
  151 {
  152         register struct radix_node *x;
  153         register caddr_t v;
  154 
  155         for (x = head, v = v_arg; x->rn_bit >= 0;) {
  156                 if (x->rn_bmask & v[x->rn_offset])
  157                         x = x->rn_right;
  158                 else
  159                         x = x->rn_left;
  160         }
  161         return (x);
  162 }
  163 
  164 /*
  165  * Same as above, but with an additional mask.
  166  * XXX note this function is used only once.
  167  */
  168 static struct radix_node *
  169 rn_search_m(v_arg, head, m_arg)
  170         struct radix_node *head;
  171         void *v_arg, *m_arg;
  172 {
  173         register struct radix_node *x;
  174         register caddr_t v = v_arg, m = m_arg;
  175 
  176         for (x = head; x->rn_bit >= 0;) {
  177                 if ((x->rn_bmask & m[x->rn_offset]) &&
  178                     (x->rn_bmask & v[x->rn_offset]))
  179                         x = x->rn_right;
  180                 else
  181                         x = x->rn_left;
  182         }
  183         return x;
  184 }
  185 
  186 int
  187 rn_refines(m_arg, n_arg)
  188         void *m_arg, *n_arg;
  189 {
  190         register caddr_t m = m_arg, n = n_arg;
  191         register caddr_t lim, lim2 = lim = n + LEN(n);
  192         int longer = LEN(n++) - (int)LEN(m++);
  193         int masks_are_equal = 1;
  194 
  195         if (longer > 0)
  196                 lim -= longer;
  197         while (n < lim) {
  198                 if (*n & ~(*m))
  199                         return 0;
  200                 if (*n++ != *m++)
  201                         masks_are_equal = 0;
  202         }
  203         while (n < lim2)
  204                 if (*n++)
  205                         return 0;
  206         if (masks_are_equal && (longer < 0))
  207                 for (lim2 = m - longer; m < lim2; )
  208                         if (*m++)
  209                                 return 1;
  210         return (!masks_are_equal);
  211 }
  212 
  213 struct radix_node *
  214 rn_lookup(v_arg, m_arg, head)
  215         void *v_arg, *m_arg;
  216         struct radix_node_head *head;
  217 {
  218         register struct radix_node *x;
  219         caddr_t netmask = 0;
  220 
  221         if (m_arg) {
  222                 x = rn_addmask(m_arg, 1, head->rnh_treetop->rn_offset);
  223                 if (x == 0)
  224                         return (0);
  225                 netmask = x->rn_key;
  226         }
  227         x = rn_match(v_arg, head);
  228         if (x && netmask) {
  229                 while (x && x->rn_mask != netmask)
  230                         x = x->rn_dupedkey;
  231         }
  232         return x;
  233 }
  234 
  235 static int
  236 rn_satisfies_leaf(trial, leaf, skip)
  237         char *trial;
  238         register struct radix_node *leaf;
  239         int skip;
  240 {
  241         register char *cp = trial, *cp2 = leaf->rn_key, *cp3 = leaf->rn_mask;
  242         char *cplim;
  243         int length = min(LEN(cp), LEN(cp2));
  244 
  245         if (cp3 == 0)
  246                 cp3 = rn_ones;
  247         else
  248                 length = min(length, *(u_char *)cp3);
  249         cplim = cp + length; cp3 += skip; cp2 += skip;
  250         for (cp += skip; cp < cplim; cp++, cp2++, cp3++)
  251                 if ((*cp ^ *cp2) & *cp3)
  252                         return 0;
  253         return 1;
  254 }
  255 
  256 struct radix_node *
  257 rn_match(v_arg, head)
  258         void *v_arg;
  259         struct radix_node_head *head;
  260 {
  261         caddr_t v = v_arg;
  262         register struct radix_node *t = head->rnh_treetop, *x;
  263         register caddr_t cp = v, cp2;
  264         caddr_t cplim;
  265         struct radix_node *saved_t, *top = t;
  266         int off = t->rn_offset, vlen = LEN(cp), matched_off;
  267         register int test, b, rn_bit;
  268 
  269         /*
  270          * Open code rn_search(v, top) to avoid overhead of extra
  271          * subroutine call.
  272          */
  273         for (; t->rn_bit >= 0; ) {
  274                 if (t->rn_bmask & cp[t->rn_offset])
  275                         t = t->rn_right;
  276                 else
  277                         t = t->rn_left;
  278         }
  279         /*
  280          * See if we match exactly as a host destination
  281          * or at least learn how many bits match, for normal mask finesse.
  282          *
  283          * It doesn't hurt us to limit how many bytes to check
  284          * to the length of the mask, since if it matches we had a genuine
  285          * match and the leaf we have is the most specific one anyway;
  286          * if it didn't match with a shorter length it would fail
  287          * with a long one.  This wins big for class B&C netmasks which
  288          * are probably the most common case...
  289          */
  290         if (t->rn_mask)
  291                 vlen = *(u_char *)t->rn_mask;
  292         cp += off; cp2 = t->rn_key + off; cplim = v + vlen;
  293         for (; cp < cplim; cp++, cp2++)
  294                 if (*cp != *cp2)
  295                         goto on1;
  296         /*
  297          * This extra grot is in case we are explicitly asked
  298          * to look up the default.  Ugh!
  299          *
  300          * Never return the root node itself, it seems to cause a
  301          * lot of confusion.
  302          */
  303         if (t->rn_flags & RNF_ROOT)
  304                 t = t->rn_dupedkey;
  305         return t;
  306 on1:
  307         test = (*cp ^ *cp2) & 0xff; /* find first bit that differs */
  308         for (b = 7; (test >>= 1) > 0;)
  309                 b--;
  310         matched_off = cp - v;
  311         b += matched_off << 3;
  312         rn_bit = -1 - b;
  313         /*
  314          * If there is a host route in a duped-key chain, it will be first.
  315          */
  316         if ((saved_t = t)->rn_mask == 0)
  317                 t = t->rn_dupedkey;
  318         for (; t; t = t->rn_dupedkey)
  319                 /*
  320                  * Even if we don't match exactly as a host,
  321                  * we may match if the leaf we wound up at is
  322                  * a route to a net.
  323                  */
  324                 if (t->rn_flags & RNF_NORMAL) {
  325                         if (rn_bit <= t->rn_bit)
  326                                 return t;
  327                 } else if (rn_satisfies_leaf(v, t, matched_off))
  328                                 return t;
  329         t = saved_t;
  330         /* start searching up the tree */
  331         do {
  332                 register struct radix_mask *m;
  333                 t = t->rn_parent;
  334                 m = t->rn_mklist;
  335                 /*
  336                  * If non-contiguous masks ever become important
  337                  * we can restore the masking and open coding of
  338                  * the search and satisfaction test and put the
  339                  * calculation of "off" back before the "do".
  340                  */
  341                 while (m) {
  342                         if (m->rm_flags & RNF_NORMAL) {
  343                                 if (rn_bit <= m->rm_bit)
  344                                         return (m->rm_leaf);
  345                         } else {
  346                                 off = min(t->rn_offset, matched_off);
  347                                 x = rn_search_m(v, t, m->rm_mask);
  348                                 while (x && x->rn_mask != m->rm_mask)
  349                                         x = x->rn_dupedkey;
  350                                 if (x && rn_satisfies_leaf(v, x, off))
  351                                         return x;
  352                         }
  353                         m = m->rm_mklist;
  354                 }
  355         } while (t != top);
  356         return 0;
  357 }
  358 
  359 #ifdef RN_DEBUG
  360 int     rn_nodenum;
  361 struct  radix_node *rn_clist;
  362 int     rn_saveinfo;
  363 int     rn_debug =  1;
  364 #endif
  365 
  366 /*
  367  * Whenever we add a new leaf to the tree, we also add a parent node,
  368  * so we allocate them as an array of two elements: the first one must be
  369  * the leaf (see RNTORT() in route.c), the second one is the parent.
  370  * This routine initializes the relevant fields of the nodes, so that
  371  * the leaf is the left child of the parent node, and both nodes have
  372  * (almost) all all fields filled as appropriate.
  373  * (XXX some fields are left unset, see the '#if 0' section).
  374  * The function returns a pointer to the parent node.
  375  */
  376 
  377 static struct radix_node *
  378 rn_newpair(v, b, nodes)
  379         void *v;
  380         int b;
  381         struct radix_node nodes[2];
  382 {
  383         register struct radix_node *tt = nodes, *t = tt + 1;
  384         t->rn_bit = b;
  385         t->rn_bmask = 0x80 >> (b & 7);
  386         t->rn_left = tt;
  387         t->rn_offset = b >> 3;
  388 
  389 #if 0  /* XXX perhaps we should fill these fields as well. */
  390         t->rn_parent = t->rn_right = NULL;
  391 
  392         tt->rn_mask = NULL;
  393         tt->rn_dupedkey = NULL;
  394         tt->rn_bmask = 0;
  395 #endif
  396         tt->rn_bit = -1;
  397         tt->rn_key = (caddr_t)v;
  398         tt->rn_parent = t;
  399         tt->rn_flags = t->rn_flags = RNF_ACTIVE;
  400         tt->rn_mklist = t->rn_mklist = 0;
  401 #ifdef RN_DEBUG
  402         tt->rn_info = rn_nodenum++; t->rn_info = rn_nodenum++;
  403         tt->rn_twin = t;
  404         tt->rn_ybro = rn_clist;
  405         rn_clist = tt;
  406 #endif
  407         return t;
  408 }
  409 
  410 static struct radix_node *
  411 rn_insert(v_arg, head, dupentry, nodes)
  412         void *v_arg;
  413         struct radix_node_head *head;
  414         int *dupentry;
  415         struct radix_node nodes[2];
  416 {
  417         caddr_t v = v_arg;
  418         struct radix_node *top = head->rnh_treetop;
  419         int head_off = top->rn_offset, vlen = (int)LEN(v);
  420         register struct radix_node *t = rn_search(v_arg, top);
  421         register caddr_t cp = v + head_off;
  422         register int b;
  423         struct radix_node *tt;
  424         /*
  425          * Find first bit at which v and t->rn_key differ
  426          */
  427     {
  428         register caddr_t cp2 = t->rn_key + head_off;
  429         register int cmp_res;
  430         caddr_t cplim = v + vlen;
  431 
  432         while (cp < cplim)
  433                 if (*cp2++ != *cp++)
  434                         goto on1;
  435         *dupentry = 1;
  436         return t;
  437 on1:
  438         *dupentry = 0;
  439         cmp_res = (cp[-1] ^ cp2[-1]) & 0xff;
  440         for (b = (cp - v) << 3; cmp_res; b--)
  441                 cmp_res >>= 1;
  442     }
  443     {
  444         register struct radix_node *p, *x = top;
  445         cp = v;
  446         do {
  447                 p = x;
  448                 if (cp[x->rn_offset] & x->rn_bmask)
  449                         x = x->rn_right;
  450                 else
  451                         x = x->rn_left;
  452         } while (b > (unsigned) x->rn_bit);
  453                                 /* x->rn_bit < b && x->rn_bit >= 0 */
  454 #ifdef RN_DEBUG
  455         if (rn_debug)
  456                 log(LOG_DEBUG, "rn_insert: Going In:\n"), traverse(p);
  457 #endif
  458         t = rn_newpair(v_arg, b, nodes); 
  459         tt = t->rn_left;
  460         if ((cp[p->rn_offset] & p->rn_bmask) == 0)
  461                 p->rn_left = t;
  462         else
  463                 p->rn_right = t;
  464         x->rn_parent = t;
  465         t->rn_parent = p; /* frees x, p as temp vars below */
  466         if ((cp[t->rn_offset] & t->rn_bmask) == 0) {
  467                 t->rn_right = x;
  468         } else {
  469                 t->rn_right = tt;
  470                 t->rn_left = x;
  471         }
  472 #ifdef RN_DEBUG
  473         if (rn_debug)
  474                 log(LOG_DEBUG, "rn_insert: Coming Out:\n"), traverse(p);
  475 #endif
  476     }
  477         return (tt);
  478 }
  479 
  480 struct radix_node *
  481 rn_addmask(n_arg, search, skip)
  482         int search, skip;
  483         void *n_arg;
  484 {
  485         caddr_t netmask = (caddr_t)n_arg;
  486         register struct radix_node *x;
  487         register caddr_t cp, cplim;
  488         register int b = 0, mlen, j;
  489         int maskduplicated, m0, isnormal;
  490         struct radix_node *saved_x;
  491         static int last_zeroed = 0;
  492 
  493         if ((mlen = LEN(netmask)) > max_keylen)
  494                 mlen = max_keylen;
  495         if (skip == 0)
  496                 skip = 1;
  497         if (mlen <= skip)
  498                 return (mask_rnhead->rnh_nodes);
  499         if (skip > 1)
  500                 bcopy(rn_ones + 1, addmask_key + 1, skip - 1);
  501         if ((m0 = mlen) > skip)
  502                 bcopy(netmask + skip, addmask_key + skip, mlen - skip);
  503         /*
  504          * Trim trailing zeroes.
  505          */
  506         for (cp = addmask_key + mlen; (cp > addmask_key) && cp[-1] == 0;)
  507                 cp--;
  508         mlen = cp - addmask_key;
  509         if (mlen <= skip) {
  510                 if (m0 >= last_zeroed)
  511                         last_zeroed = mlen;
  512                 return (mask_rnhead->rnh_nodes);
  513         }
  514         if (m0 < last_zeroed)
  515                 bzero(addmask_key + m0, last_zeroed - m0);
  516         *addmask_key = last_zeroed = mlen;
  517         x = rn_search(addmask_key, rn_masktop);
  518         if (bcmp(addmask_key, x->rn_key, mlen) != 0)
  519                 x = 0;
  520         if (x || search)
  521                 return (x);
  522         R_Zalloc(x, struct radix_node *, max_keylen + 2 * sizeof (*x));
  523         if ((saved_x = x) == 0)
  524                 return (0);
  525         netmask = cp = (caddr_t)(x + 2);
  526         bcopy(addmask_key, cp, mlen);
  527         x = rn_insert(cp, mask_rnhead, &maskduplicated, x);
  528         if (maskduplicated) {
  529                 log(LOG_ERR, "rn_addmask: mask impossibly already in tree");
  530                 Free(saved_x);
  531                 return (x);
  532         }
  533         /*
  534          * Calculate index of mask, and check for normalcy.
  535          * First find the first byte with a 0 bit, then if there are
  536          * more bits left (remember we already trimmed the trailing 0's),
  537          * the pattern must be one of those in normal_chars[], or we have
  538          * a non-contiguous mask.
  539          */
  540         cplim = netmask + mlen;
  541         isnormal = 1;
  542         for (cp = netmask + skip; (cp < cplim) && *(u_char *)cp == 0xff;)
  543                 cp++;
  544         if (cp != cplim) {
  545                 static char normal_chars[] = {
  546                         0, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff};
  547 
  548                 for (j = 0x80; (j & *cp) != 0; j >>= 1)
  549                         b++;
  550                 if (*cp != normal_chars[b] || cp != (cplim - 1))
  551                         isnormal = 0;
  552         }
  553         b += (cp - netmask) << 3;
  554         x->rn_bit = -1 - b;
  555         if (isnormal)
  556                 x->rn_flags |= RNF_NORMAL;
  557         return (x);
  558 }
  559 
  560 static int      /* XXX: arbitrary ordering for non-contiguous masks */
  561 rn_lexobetter(m_arg, n_arg)
  562         void *m_arg, *n_arg;
  563 {
  564         register u_char *mp = m_arg, *np = n_arg, *lim;
  565 
  566         if (LEN(mp) > LEN(np))
  567                 return 1;  /* not really, but need to check longer one first */
  568         if (LEN(mp) == LEN(np))
  569                 for (lim = mp + LEN(mp); mp < lim;)
  570                         if (*mp++ > *np++)
  571                                 return 1;
  572         return 0;
  573 }
  574 
  575 static struct radix_mask *
  576 rn_new_radix_mask(tt, next)
  577         register struct radix_node *tt;
  578         register struct radix_mask *next;
  579 {
  580         register struct radix_mask *m;
  581 
  582         MKGet(m);
  583         if (m == 0) {
  584                 log(LOG_ERR, "Mask for route not entered\n");
  585                 return (0);
  586         }
  587         bzero(m, sizeof *m);
  588         m->rm_bit = tt->rn_bit;
  589         m->rm_flags = tt->rn_flags;
  590         if (tt->rn_flags & RNF_NORMAL)
  591                 m->rm_leaf = tt;
  592         else
  593                 m->rm_mask = tt->rn_mask;
  594         m->rm_mklist = next;
  595         tt->rn_mklist = m;
  596         return m;
  597 }
  598 
  599 struct radix_node *
  600 rn_addroute(v_arg, n_arg, head, treenodes)
  601         void *v_arg, *n_arg;
  602         struct radix_node_head *head;
  603         struct radix_node treenodes[2];
  604 {
  605         caddr_t v = (caddr_t)v_arg, netmask = (caddr_t)n_arg;
  606         register struct radix_node *t, *x = 0, *tt;
  607         struct radix_node *saved_tt, *top = head->rnh_treetop;
  608         short b = 0, b_leaf = 0;
  609         int keyduplicated;
  610         caddr_t mmask;
  611         struct radix_mask *m, **mp;
  612 
  613         /*
  614          * In dealing with non-contiguous masks, there may be
  615          * many different routes which have the same mask.
  616          * We will find it useful to have a unique pointer to
  617          * the mask to speed avoiding duplicate references at
  618          * nodes and possibly save time in calculating indices.
  619          */
  620         if (netmask)  {
  621                 if ((x = rn_addmask(netmask, 0, top->rn_offset)) == 0)
  622                         return (0);
  623                 b_leaf = x->rn_bit;
  624                 b = -1 - x->rn_bit;
  625                 netmask = x->rn_key;
  626         }
  627         /*
  628          * Deal with duplicated keys: attach node to previous instance
  629          */
  630         saved_tt = tt = rn_insert(v, head, &keyduplicated, treenodes);
  631         if (keyduplicated) {
  632                 for (t = tt; tt; t = tt, tt = tt->rn_dupedkey) {
  633                         if (tt->rn_mask == netmask)
  634                                 return (0);
  635                         if (netmask == 0 ||
  636                             (tt->rn_mask &&
  637                              ((b_leaf < tt->rn_bit) /* index(netmask) > node */
  638                               || rn_refines(netmask, tt->rn_mask)
  639                               || rn_lexobetter(netmask, tt->rn_mask))))
  640                                 break;
  641                 }
  642                 /*
  643                  * If the mask is not duplicated, we wouldn't
  644                  * find it among possible duplicate key entries
  645                  * anyway, so the above test doesn't hurt.
  646                  *
  647                  * We sort the masks for a duplicated key the same way as
  648                  * in a masklist -- most specific to least specific.
  649                  * This may require the unfortunate nuisance of relocating
  650                  * the head of the list.
  651                  *
  652                  * We also reverse, or doubly link the list through the
  653                  * parent pointer.
  654                  */
  655                 if (tt == saved_tt) {
  656                         struct  radix_node *xx = x;
  657                         /* link in at head of list */
  658                         (tt = treenodes)->rn_dupedkey = t;
  659                         tt->rn_flags = t->rn_flags;
  660                         tt->rn_parent = x = t->rn_parent;
  661                         t->rn_parent = tt;                      /* parent */
  662                         if (x->rn_left == t)
  663                                 x->rn_left = tt;
  664                         else
  665                                 x->rn_right = tt;
  666                         saved_tt = tt; x = xx;
  667                 } else {
  668                         (tt = treenodes)->rn_dupedkey = t->rn_dupedkey;
  669                         t->rn_dupedkey = tt;
  670                         tt->rn_parent = t;                      /* parent */
  671                         if (tt->rn_dupedkey)                    /* parent */
  672                                 tt->rn_dupedkey->rn_parent = tt; /* parent */
  673                 }
  674 #ifdef RN_DEBUG
  675                 t=tt+1; tt->rn_info = rn_nodenum++; t->rn_info = rn_nodenum++;
  676                 tt->rn_twin = t; tt->rn_ybro = rn_clist; rn_clist = tt;
  677 #endif
  678                 tt->rn_key = (caddr_t) v;
  679                 tt->rn_bit = -1;
  680                 tt->rn_flags = RNF_ACTIVE;
  681         }
  682         /*
  683          * Put mask in tree.
  684          */
  685         if (netmask) {
  686                 tt->rn_mask = netmask;
  687                 tt->rn_bit = x->rn_bit;
  688                 tt->rn_flags |= x->rn_flags & RNF_NORMAL;
  689         }
  690         t = saved_tt->rn_parent;
  691         if (keyduplicated)
  692                 goto on2;
  693         b_leaf = -1 - t->rn_bit;
  694         if (t->rn_right == saved_tt)
  695                 x = t->rn_left;
  696         else
  697                 x = t->rn_right;
  698         /* Promote general routes from below */
  699         if (x->rn_bit < 0) {
  700             for (mp = &t->rn_mklist; x; x = x->rn_dupedkey)
  701                 if (x->rn_mask && (x->rn_bit >= b_leaf) && x->rn_mklist == 0) {
  702                         *mp = m = rn_new_radix_mask(x, 0);
  703                         if (m)
  704                                 mp = &m->rm_mklist;
  705                 }
  706         } else if (x->rn_mklist) {
  707                 /*
  708                  * Skip over masks whose index is > that of new node
  709                  */
  710                 for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist)
  711                         if (m->rm_bit >= b_leaf)
  712                                 break;
  713                 t->rn_mklist = m; *mp = 0;
  714         }
  715 on2:
  716         /* Add new route to highest possible ancestor's list */
  717         if ((netmask == 0) || (b > t->rn_bit ))
  718                 return tt; /* can't lift at all */
  719         b_leaf = tt->rn_bit;
  720         do {
  721                 x = t;
  722                 t = t->rn_parent;
  723         } while (b <= t->rn_bit && x != top);
  724         /*
  725          * Search through routes associated with node to
  726          * insert new route according to index.
  727          * Need same criteria as when sorting dupedkeys to avoid
  728          * double loop on deletion.
  729          */
  730         for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist) {
  731                 if (m->rm_bit < b_leaf)
  732                         continue;
  733                 if (m->rm_bit > b_leaf)
  734                         break;
  735                 if (m->rm_flags & RNF_NORMAL) {
  736                         mmask = m->rm_leaf->rn_mask;
  737                         if (tt->rn_flags & RNF_NORMAL) {
  738                             log(LOG_ERR,
  739                                 "Non-unique normal route, mask not entered\n");
  740                                 return tt;
  741                         }
  742                 } else
  743                         mmask = m->rm_mask;
  744                 if (mmask == netmask) {
  745                         m->rm_refs++;
  746                         tt->rn_mklist = m;
  747                         return tt;
  748                 }
  749                 if (rn_refines(netmask, mmask)
  750                     || rn_lexobetter(netmask, mmask))
  751                         break;
  752         }
  753         *mp = rn_new_radix_mask(tt, *mp);
  754         return tt;
  755 }
  756 
  757 struct radix_node *
  758 rn_delete(v_arg, netmask_arg, head)
  759         void *v_arg, *netmask_arg;
  760         struct radix_node_head *head;
  761 {
  762         register struct radix_node *t, *p, *x, *tt;
  763         struct radix_mask *m, *saved_m, **mp;
  764         struct radix_node *dupedkey, *saved_tt, *top;
  765         caddr_t v, netmask;
  766         int b, head_off, vlen;
  767 
  768         v = v_arg;
  769         netmask = netmask_arg;
  770         x = head->rnh_treetop;
  771         tt = rn_search(v, x);
  772         head_off = x->rn_offset;
  773         vlen =  LEN(v);
  774         saved_tt = tt;
  775         top = x;
  776         if (tt == 0 ||
  777             bcmp(v + head_off, tt->rn_key + head_off, vlen - head_off))
  778                 return (0);
  779         /*
  780          * Delete our route from mask lists.
  781          */
  782         if (netmask) {
  783                 if ((x = rn_addmask(netmask, 1, head_off)) == 0)
  784                         return (0);
  785                 netmask = x->rn_key;
  786                 while (tt->rn_mask != netmask)
  787                         if ((tt = tt->rn_dupedkey) == 0)
  788                                 return (0);
  789         }
  790         if (tt->rn_mask == 0 || (saved_m = m = tt->rn_mklist) == 0)
  791                 goto on1;
  792         if (tt->rn_flags & RNF_NORMAL) {
  793                 if (m->rm_leaf != tt || m->rm_refs > 0) {
  794                         log(LOG_ERR, "rn_delete: inconsistent annotation\n");
  795                         return 0;  /* dangling ref could cause disaster */
  796                 }
  797         } else {
  798                 if (m->rm_mask != tt->rn_mask) {
  799                         log(LOG_ERR, "rn_delete: inconsistent annotation\n");
  800                         goto on1;
  801                 }
  802                 if (--m->rm_refs >= 0)
  803                         goto on1;
  804         }
  805         b = -1 - tt->rn_bit;
  806         t = saved_tt->rn_parent;
  807         if (b > t->rn_bit)
  808                 goto on1; /* Wasn't lifted at all */
  809         do {
  810                 x = t;
  811                 t = t->rn_parent;
  812         } while (b <= t->rn_bit && x != top);
  813         for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist)
  814                 if (m == saved_m) {
  815                         *mp = m->rm_mklist;
  816                         MKFree(m);
  817                         break;
  818                 }
  819         if (m == 0) {
  820                 log(LOG_ERR, "rn_delete: couldn't find our annotation\n");
  821                 if (tt->rn_flags & RNF_NORMAL)
  822                         return (0); /* Dangling ref to us */
  823         }
  824 on1:
  825         /*
  826          * Eliminate us from tree
  827          */
  828         if (tt->rn_flags & RNF_ROOT)
  829                 return (0);
  830 #ifdef RN_DEBUG
  831         /* Get us out of the creation list */
  832         for (t = rn_clist; t && t->rn_ybro != tt; t = t->rn_ybro) {}
  833         if (t) t->rn_ybro = tt->rn_ybro;
  834 #endif
  835         t = tt->rn_parent;
  836         dupedkey = saved_tt->rn_dupedkey;
  837         if (dupedkey) {
  838                 /*
  839                  * Here, tt is the deletion target and
  840                  * saved_tt is the head of the dupekey chain.
  841                  */
  842                 if (tt == saved_tt) {
  843                         /* remove from head of chain */
  844                         x = dupedkey; x->rn_parent = t;
  845                         if (t->rn_left == tt)
  846                                 t->rn_left = x;
  847                         else
  848                                 t->rn_right = x;
  849                 } else {
  850                         /* find node in front of tt on the chain */
  851                         for (x = p = saved_tt; p && p->rn_dupedkey != tt;)
  852                                 p = p->rn_dupedkey;
  853                         if (p) {
  854                                 p->rn_dupedkey = tt->rn_dupedkey;
  855                                 if (tt->rn_dupedkey)            /* parent */
  856                                         tt->rn_dupedkey->rn_parent = p;
  857                                                                 /* parent */
  858                         } else log(LOG_ERR, "rn_delete: couldn't find us\n");
  859                 }
  860                 t = tt + 1;
  861                 if  (t->rn_flags & RNF_ACTIVE) {
  862 #ifndef RN_DEBUG
  863                         *++x = *t;
  864                         p = t->rn_parent;
  865 #else
  866                         b = t->rn_info;
  867                         *++x = *t;
  868                         t->rn_info = b;
  869                         p = t->rn_parent;
  870 #endif
  871                         if (p->rn_left == t)
  872                                 p->rn_left = x;
  873                         else
  874                                 p->rn_right = x;
  875                         x->rn_left->rn_parent = x;
  876                         x->rn_right->rn_parent = x;
  877                 }
  878                 goto out;
  879         }
  880         if (t->rn_left == tt)
  881                 x = t->rn_right;
  882         else
  883                 x = t->rn_left;
  884         p = t->rn_parent;
  885         if (p->rn_right == t)
  886                 p->rn_right = x;
  887         else
  888                 p->rn_left = x;
  889         x->rn_parent = p;
  890         /*
  891          * Demote routes attached to us.
  892          */
  893         if (t->rn_mklist) {
  894                 if (x->rn_bit >= 0) {
  895                         for (mp = &x->rn_mklist; (m = *mp);)
  896                                 mp = &m->rm_mklist;
  897                         *mp = t->rn_mklist;
  898                 } else {
  899                         /* If there are any key,mask pairs in a sibling
  900                            duped-key chain, some subset will appear sorted
  901                            in the same order attached to our mklist */
  902                         for (m = t->rn_mklist; m && x; x = x->rn_dupedkey)
  903                                 if (m == x->rn_mklist) {
  904                                         struct radix_mask *mm = m->rm_mklist;
  905                                         x->rn_mklist = 0;
  906                                         if (--(m->rm_refs) < 0)
  907                                                 MKFree(m);
  908                                         m = mm;
  909                                 }
  910                         if (m)
  911                                 log(LOG_ERR,
  912                                     "rn_delete: Orphaned Mask %p at %p\n",
  913                                     (void *)m, (void *)x);
  914                 }
  915         }
  916         /*
  917          * We may be holding an active internal node in the tree.
  918          */
  919         x = tt + 1;
  920         if (t != x) {
  921 #ifndef RN_DEBUG
  922                 *t = *x;
  923 #else
  924                 b = t->rn_info;
  925                 *t = *x;
  926                 t->rn_info = b;
  927 #endif
  928                 t->rn_left->rn_parent = t;
  929                 t->rn_right->rn_parent = t;
  930                 p = x->rn_parent;
  931                 if (p->rn_left == x)
  932                         p->rn_left = t;
  933                 else
  934                         p->rn_right = t;
  935         }
  936 out:
  937         tt->rn_flags &= ~RNF_ACTIVE;
  938         tt[1].rn_flags &= ~RNF_ACTIVE;
  939         return (tt);
  940 }
  941 
  942 /*
  943  * This is the same as rn_walktree() except for the parameters and the
  944  * exit.
  945  */
  946 static int
  947 rn_walktree_from(h, a, m, f, w)
  948         struct radix_node_head *h;
  949         void *a, *m;
  950         walktree_f_t *f;
  951         void *w;
  952 {
  953         int error;
  954         struct radix_node *base, *next;
  955         u_char *xa = (u_char *)a;
  956         u_char *xm = (u_char *)m;
  957         register struct radix_node *rn, *last = 0 /* shut up gcc */;
  958         int stopping = 0;
  959         int lastb;
  960 
  961         /*
  962          * rn_search_m is sort-of-open-coded here. We cannot use the
  963          * function because we need to keep track of the last node seen.
  964          */
  965         /* printf("about to search\n"); */
  966         for (rn = h->rnh_treetop; rn->rn_bit >= 0; ) {
  967                 last = rn;
  968                 /* printf("rn_bit %d, rn_bmask %x, xm[rn_offset] %x\n",
  969                        rn->rn_bit, rn->rn_bmask, xm[rn->rn_offset]); */
  970                 if (!(rn->rn_bmask & xm[rn->rn_offset])) {
  971                         break;
  972                 }
  973                 if (rn->rn_bmask & xa[rn->rn_offset]) {
  974                         rn = rn->rn_right;
  975                 } else {
  976                         rn = rn->rn_left;
  977                 }
  978         }
  979         /* printf("done searching\n"); */
  980 
  981         /*
  982          * Two cases: either we stepped off the end of our mask,
  983          * in which case last == rn, or we reached a leaf, in which
  984          * case we want to start from the last node we looked at.
  985          * Either way, last is the node we want to start from.
  986          */
  987         rn = last;
  988         lastb = rn->rn_bit;
  989 
  990         /* printf("rn %p, lastb %d\n", rn, lastb);*/
  991 
  992         /*
  993          * This gets complicated because we may delete the node
  994          * while applying the function f to it, so we need to calculate
  995          * the successor node in advance.
  996          */
  997         while (rn->rn_bit >= 0)
  998                 rn = rn->rn_left;
  999 
 1000         while (!stopping) {
 1001                 /* printf("node %p (%d)\n", rn, rn->rn_bit); */
 1002                 base = rn;
 1003                 /* If at right child go back up, otherwise, go right */
 1004                 while (rn->rn_parent->rn_right == rn
 1005                        && !(rn->rn_flags & RNF_ROOT)) {
 1006                         rn = rn->rn_parent;
 1007 
 1008                         /* if went up beyond last, stop */
 1009                         if (rn->rn_bit <= lastb) {
 1010                                 stopping = 1;
 1011                                 /* printf("up too far\n"); */
 1012                                 /*
 1013                                  * XXX we should jump to the 'Process leaves'
 1014                                  * part, because the values of 'rn' and 'next'
 1015                                  * we compute will not be used. Not a big deal
 1016                                  * because this loop will terminate, but it is
 1017                                  * inefficient and hard to understand!
 1018                                  */
 1019                         }
 1020                 }
 1021                 
 1022                 /* 
 1023                  * At the top of the tree, no need to traverse the right
 1024                  * half, prevent the traversal of the entire tree in the
 1025                  * case of default route.
 1026                  */
 1027                 if (rn->rn_parent->rn_flags & RNF_ROOT)
 1028                         stopping = 1;
 1029 
 1030                 /* Find the next *leaf* since next node might vanish, too */
 1031                 for (rn = rn->rn_parent->rn_right; rn->rn_bit >= 0;)
 1032                         rn = rn->rn_left;
 1033                 next = rn;
 1034                 /* Process leaves */
 1035                 while ((rn = base) != 0) {
 1036                         base = rn->rn_dupedkey;
 1037                         /* printf("leaf %p\n", rn); */
 1038                         if (!(rn->rn_flags & RNF_ROOT)
 1039                             && (error = (*f)(rn, w)))
 1040                                 return (error);
 1041                 }
 1042                 rn = next;
 1043 
 1044                 if (rn->rn_flags & RNF_ROOT) {
 1045                         /* printf("root, stopping"); */
 1046                         stopping = 1;
 1047                 }
 1048 
 1049         }
 1050         return 0;
 1051 }
 1052 
 1053 static int
 1054 rn_walktree(h, f, w)
 1055         struct radix_node_head *h;
 1056         walktree_f_t *f;
 1057         void *w;
 1058 {
 1059         int error;
 1060         struct radix_node *base, *next;
 1061         register struct radix_node *rn = h->rnh_treetop;
 1062         /*
 1063          * This gets complicated because we may delete the node
 1064          * while applying the function f to it, so we need to calculate
 1065          * the successor node in advance.
 1066          */
 1067         /* First time through node, go left */
 1068         while (rn->rn_bit >= 0)
 1069                 rn = rn->rn_left;
 1070         for (;;) {
 1071                 base = rn;
 1072                 /* If at right child go back up, otherwise, go right */
 1073                 while (rn->rn_parent->rn_right == rn
 1074                        && (rn->rn_flags & RNF_ROOT) == 0)
 1075                         rn = rn->rn_parent;
 1076                 /* Find the next *leaf* since next node might vanish, too */
 1077                 for (rn = rn->rn_parent->rn_right; rn->rn_bit >= 0;)
 1078                         rn = rn->rn_left;
 1079                 next = rn;
 1080                 /* Process leaves */
 1081                 while ((rn = base)) {
 1082                         base = rn->rn_dupedkey;
 1083                         if (!(rn->rn_flags & RNF_ROOT)
 1084                             && (error = (*f)(rn, w)))
 1085                                 return (error);
 1086                 }
 1087                 rn = next;
 1088                 if (rn->rn_flags & RNF_ROOT)
 1089                         return (0);
 1090         }
 1091         /* NOTREACHED */
 1092 }
 1093 
 1094 /*
 1095  * Allocate and initialize an empty tree. This has 3 nodes, which are
 1096  * part of the radix_node_head (in the order <left,root,right>) and are
 1097  * marked RNF_ROOT so they cannot be freed.
 1098  * The leaves have all-zero and all-one keys, with significant
 1099  * bits starting at 'off'.
 1100  * Return 1 on success, 0 on error.
 1101  */
 1102 int
 1103 rn_inithead(head, off)
 1104         void **head;
 1105         int off;
 1106 {
 1107         register struct radix_node_head *rnh;
 1108         register struct radix_node *t, *tt, *ttt;
 1109         if (*head)
 1110                 return (1);
 1111         R_Zalloc(rnh, struct radix_node_head *, sizeof (*rnh));
 1112         if (rnh == 0)
 1113                 return (0);
 1114 #ifdef _KERNEL
 1115         RADIX_NODE_HEAD_LOCK_INIT(rnh);
 1116 #endif
 1117         *head = rnh;
 1118         t = rn_newpair(rn_zeros, off, rnh->rnh_nodes);
 1119         ttt = rnh->rnh_nodes + 2;
 1120         t->rn_right = ttt;
 1121         t->rn_parent = t;
 1122         tt = t->rn_left;        /* ... which in turn is rnh->rnh_nodes */
 1123         tt->rn_flags = t->rn_flags = RNF_ROOT | RNF_ACTIVE;
 1124         tt->rn_bit = -1 - off;
 1125         *ttt = *tt;
 1126         ttt->rn_key = rn_ones;
 1127         rnh->rnh_addaddr = rn_addroute;
 1128         rnh->rnh_deladdr = rn_delete;
 1129         rnh->rnh_matchaddr = rn_match;
 1130         rnh->rnh_lookup = rn_lookup;
 1131         rnh->rnh_walktree = rn_walktree;
 1132         rnh->rnh_walktree_from = rn_walktree_from;
 1133         rnh->rnh_treetop = t;
 1134         return (1);
 1135 }
 1136 
 1137 void
 1138 rn_init()
 1139 {
 1140         char *cp, *cplim;
 1141 #ifdef _KERNEL
 1142         struct domain *dom;
 1143 
 1144         for (dom = domains; dom; dom = dom->dom_next)
 1145                 if (dom->dom_maxrtkey > max_keylen)
 1146                         max_keylen = dom->dom_maxrtkey;
 1147 #endif
 1148         if (max_keylen == 0) {
 1149                 log(LOG_ERR,
 1150                     "rn_init: radix functions require max_keylen be set\n");
 1151                 return;
 1152         }
 1153         R_Malloc(rn_zeros, char *, 3 * max_keylen);
 1154         if (rn_zeros == NULL)
 1155                 panic("rn_init");
 1156         bzero(rn_zeros, 3 * max_keylen);
 1157         rn_ones = cp = rn_zeros + max_keylen;
 1158         addmask_key = cplim = rn_ones + max_keylen;
 1159         while (cp < cplim)
 1160                 *cp++ = -1;
 1161         if (rn_inithead((void **)(void *)&mask_rnhead, 0) == 0)
 1162                 panic("rn_init 2");
 1163 }

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