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 /*      $NetBSD: radix.c,v 1.49 2020/10/18 13:07:31 gson Exp $  */
    2 
    3 /*
    4  * Copyright (c) 1988, 1989, 1993
    5  *      The Regents of the University of California.  All rights reserved.
    6  *
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions and the following disclaimer.
   12  * 2. Redistributions in binary form must reproduce the above copyright
   13  *    notice, this list of conditions and the following disclaimer in the
   14  *    documentation and/or other materials provided with the distribution.
   15  * 3. Neither the name of the University nor the names of its contributors
   16  *    may be used to endorse or promote products derived from this software
   17  *    without specific prior written permission.
   18  *
   19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   29  * SUCH DAMAGE.
   30  *
   31  *      @(#)radix.c     8.6 (Berkeley) 10/17/95
   32  */
   33 
   34 /*
   35  * Routines to build and maintain radix trees for routing lookups.
   36  */
   37 
   38 #include <sys/cdefs.h>
   39 __KERNEL_RCSID(0, "$NetBSD: radix.c,v 1.49 2020/10/18 13:07:31 gson Exp $");
   40 
   41 #ifndef _NET_RADIX_H_
   42 #include <sys/param.h>
   43 #include <sys/queue.h>
   44 #include <sys/kmem.h>
   45 #ifdef  _KERNEL
   46 #ifdef _KERNEL_OPT
   47 #include "opt_inet.h"
   48 #endif
   49 
   50 #include <sys/systm.h>
   51 #include <sys/malloc.h>
   52 #define M_DONTWAIT M_NOWAIT
   53 #include <sys/domain.h>
   54 #else
   55 #include <stdlib.h>
   56 #endif
   57 #include <sys/syslog.h>
   58 #include <net/radix.h>
   59 #endif
   60 
   61 typedef void (*rn_printer_t)(void *, const char *fmt, ...);
   62 
   63 int     max_keylen;
   64 struct radix_mask *rn_mkfreelist;
   65 struct radix_node_head *mask_rnhead;
   66 static char *addmask_key;
   67 static const char normal_chars[] =
   68     {0, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, -1};
   69 static char *rn_zeros, *rn_ones;
   70 
   71 #define rn_masktop (mask_rnhead->rnh_treetop)
   72 
   73 static int rn_satisfies_leaf(const char *, struct radix_node *, int);
   74 static int rn_lexobetter(const void *, const void *);
   75 static struct radix_mask *rn_new_radix_mask(struct radix_node *,
   76     struct radix_mask *);
   77 static struct radix_node *rn_walknext(struct radix_node *, rn_printer_t,
   78     void *);
   79 static struct radix_node *rn_walkfirst(struct radix_node *, rn_printer_t,
   80     void *);
   81 static void rn_nodeprint(struct radix_node *, rn_printer_t, void *,
   82     const char *);
   83 
   84 #define SUBTREE_OPEN    "[ "
   85 #define SUBTREE_CLOSE   " ]"
   86 
   87 #ifdef RN_DEBUG
   88 static void rn_treeprint(struct radix_node_head *, rn_printer_t, void *);
   89 #endif /* RN_DEBUG */
   90 
   91 /*
   92  * The data structure for the keys is a radix tree with one way
   93  * branching removed.  The index rn_b at an internal node n represents a bit
   94  * position to be tested.  The tree is arranged so that all descendants
   95  * of a node n have keys whose bits all agree up to position rn_b - 1.
   96  * (We say the index of n is rn_b.)
   97  *
   98  * There is at least one descendant which has a one bit at position rn_b,
   99  * and at least one with a zero there.
  100  *
  101  * A route is determined by a pair of key and mask.  We require that the
  102  * bit-wise logical and of the key and mask to be the key.
  103  * We define the index of a route to associated with the mask to be
  104  * the first bit number in the mask where 0 occurs (with bit number 0
  105  * representing the highest order bit).
  106  *
  107  * We say a mask is normal if every bit is 0, past the index of the mask.
  108  * If a node n has a descendant (k, m) with index(m) == index(n) == rn_b,
  109  * and m is a normal mask, then the route applies to every descendant of n.
  110  * If the index(m) < rn_b, this implies the trailing last few bits of k
  111  * before bit b are all 0, (and hence consequently true of every descendant
  112  * of n), so the route applies to all descendants of the node as well.
  113  *
  114  * Similar logic shows that a non-normal mask m such that
  115  * index(m) <= index(n) could potentially apply to many children of n.
  116  * Thus, for each non-host route, we attach its mask to a list at an internal
  117  * node as high in the tree as we can go.
  118  *
  119  * The present version of the code makes use of normal routes in short-
  120  * circuiting an explicit mask and compare operation when testing whether
  121  * a key satisfies a normal route, and also in remembering the unique leaf
  122  * that governs a subtree.
  123  */
  124 
  125 struct radix_node *
  126 rn_search(
  127         const void *v_arg,
  128         struct radix_node *head)
  129 {
  130         const u_char * const v = v_arg;
  131         struct radix_node *x;
  132 
  133         for (x = head; x->rn_b >= 0;) {
  134                 if (x->rn_bmask & v[x->rn_off])
  135                         x = x->rn_r;
  136                 else
  137                         x = x->rn_l;
  138         }
  139         return x;
  140 }
  141 
  142 struct radix_node *
  143 rn_search_m(
  144         const void *v_arg,
  145         struct radix_node *head,
  146         const void *m_arg)
  147 {
  148         struct radix_node *x;
  149         const u_char * const v = v_arg;
  150         const u_char * const m = m_arg;
  151 
  152         for (x = head; x->rn_b >= 0;) {
  153                 if ((x->rn_bmask & m[x->rn_off]) &&
  154                     (x->rn_bmask & v[x->rn_off]))
  155                         x = x->rn_r;
  156                 else
  157                         x = x->rn_l;
  158         }
  159         return x;
  160 }
  161 
  162 int
  163 rn_refines(
  164         const void *m_arg,
  165         const void *n_arg)
  166 {
  167         const char *m = m_arg;
  168         const char *n = n_arg;
  169         const char *lim = n + *(const u_char *)n;
  170         const char *lim2 = lim;
  171         int longer = (*(const u_char *)n++) - (int)(*(const u_char *)m++);
  172         int masks_are_equal = 1;
  173 
  174         if (longer > 0)
  175                 lim -= longer;
  176         while (n < lim) {
  177                 if (*n & ~(*m))
  178                         return 0;
  179                 if (*n++ != *m++)
  180                         masks_are_equal = 0;
  181         }
  182         while (n < lim2)
  183                 if (*n++)
  184                         return 0;
  185         if (masks_are_equal && (longer < 0))
  186                 for (lim2 = m - longer; m < lim2; )
  187                         if (*m++)
  188                                 return 1;
  189         return !masks_are_equal;
  190 }
  191 
  192 struct radix_node *
  193 rn_lookup(
  194         const void *v_arg,
  195         const void *m_arg,
  196         struct radix_node_head *head)
  197 {
  198         struct radix_node *x;
  199         const char *netmask = NULL;
  200 
  201         if (m_arg) {
  202                 if ((x = rn_addmask(m_arg, 1, head->rnh_treetop->rn_off)) == 0)
  203                         return NULL;
  204                 netmask = x->rn_key;
  205         }
  206         x = rn_match(v_arg, head);
  207         if (x != NULL && netmask != NULL) {
  208                 while (x != NULL && x->rn_mask != netmask)
  209                         x = x->rn_dupedkey;
  210         }
  211         return x;
  212 }
  213 
  214 static int
  215 rn_satisfies_leaf(
  216         const char *trial,
  217         struct radix_node *leaf,
  218         int skip)
  219 {
  220         const char *cp = trial;
  221         const char *cp2 = leaf->rn_key;
  222         const char *cp3 = leaf->rn_mask;
  223         const char *cplim;
  224         int length = uimin(*(const u_char *)cp, *(const u_char *)cp2);
  225 
  226         if (cp3 == 0)
  227                 cp3 = rn_ones;
  228         else
  229                 length = uimin(length, *(const u_char *)cp3);
  230         cplim = cp + length; cp3 += skip; cp2 += skip;
  231         for (cp += skip; cp < cplim; cp++, cp2++, cp3++)
  232                 if ((*cp ^ *cp2) & *cp3)
  233                         return 0;
  234         return 1;
  235 }
  236 
  237 struct radix_node *
  238 rn_match(
  239         const void *v_arg,
  240         struct radix_node_head *head)
  241 {
  242         const char * const v = v_arg;
  243         struct radix_node *t = head->rnh_treetop;
  244         struct radix_node *top = t;
  245         struct radix_node *x;
  246         struct radix_node *saved_t;
  247         const char *cp = v;
  248         const char *cp2;
  249         const char *cplim;
  250         int off = t->rn_off;
  251         int vlen = *(const u_char *)cp;
  252         int matched_off;
  253         int test, b, rn_b;
  254 
  255         /*
  256          * Open code rn_search(v, top) to avoid overhead of extra
  257          * subroutine call.
  258          */
  259         for (; t->rn_b >= 0; ) {
  260                 if (t->rn_bmask & cp[t->rn_off])
  261                         t = t->rn_r;
  262                 else
  263                         t = t->rn_l;
  264         }
  265         /*
  266          * See if we match exactly as a host destination
  267          * or at least learn how many bits match, for normal mask finesse.
  268          *
  269          * It doesn't hurt us to limit how many bytes to check
  270          * to the length of the mask, since if it matches we had a genuine
  271          * match and the leaf we have is the most specific one anyway;
  272          * if it didn't match with a shorter length it would fail
  273          * with a long one.  This wins big for class B&C netmasks which
  274          * are probably the most common case...
  275          */
  276         if (t->rn_mask)
  277                 vlen = *(const u_char *)t->rn_mask;
  278         cp += off; cp2 = t->rn_key + off; cplim = v + vlen;
  279         for (; cp < cplim; cp++, cp2++)
  280                 if (*cp != *cp2)
  281                         goto on1;
  282         /*
  283          * This extra grot is in case we are explicitly asked
  284          * to look up the default.  Ugh!
  285          */
  286         if ((t->rn_flags & RNF_ROOT) && t->rn_dupedkey)
  287                 t = t->rn_dupedkey;
  288         return t;
  289 on1:
  290         test = (*cp ^ *cp2) & 0xff; /* find first bit that differs */
  291         for (b = 7; (test >>= 1) > 0;)
  292                 b--;
  293         matched_off = cp - v;
  294         b += matched_off << 3;
  295         rn_b = -1 - b;
  296         /*
  297          * If there is a host route in a duped-key chain, it will be first.
  298          */
  299         if ((saved_t = t)->rn_mask == 0)
  300                 t = t->rn_dupedkey;
  301         for (; t; t = t->rn_dupedkey)
  302                 /*
  303                  * Even if we don't match exactly as a host,
  304                  * we may match if the leaf we wound up at is
  305                  * a route to a net.
  306                  */
  307                 if (t->rn_flags & RNF_NORMAL) {
  308                         if (rn_b <= t->rn_b)
  309                                 return t;
  310                 } else if (rn_satisfies_leaf(v, t, matched_off))
  311                                 return t;
  312         t = saved_t;
  313         /* start searching up the tree */
  314         do {
  315                 struct radix_mask *m;
  316                 t = t->rn_p;
  317                 m = t->rn_mklist;
  318                 if (m) {
  319                         /*
  320                          * If non-contiguous masks ever become important
  321                          * we can restore the masking and open coding of
  322                          * the search and satisfaction test and put the
  323                          * calculation of "off" back before the "do".
  324                          */
  325                         do {
  326                                 if (m->rm_flags & RNF_NORMAL) {
  327                                         if (rn_b <= m->rm_b)
  328                                                 return m->rm_leaf;
  329                                 } else {
  330                                         off = uimin(t->rn_off, matched_off);
  331                                         x = rn_search_m(v, t, m->rm_mask);
  332                                         while (x && x->rn_mask != m->rm_mask)
  333                                                 x = x->rn_dupedkey;
  334                                         if (x && rn_satisfies_leaf(v, x, off))
  335                                                 return x;
  336                                 }
  337                                 m = m->rm_mklist;
  338                         } while (m);
  339                 }
  340         } while (t != top);
  341         return NULL;
  342 }
  343 
  344 static void
  345 rn_nodeprint(struct radix_node *rn, rn_printer_t printer, void *arg,
  346     const char *delim)
  347 {
  348         (*printer)(arg, "%s(%s%p: p<%p> l<%p> r<%p>)",
  349             delim, ((void *)rn == arg) ? "*" : "", rn, rn->rn_p,
  350             rn->rn_l, rn->rn_r);
  351 }
  352 
  353 #ifdef RN_DEBUG
  354 int     rn_debug =  1;
  355 
  356 static void
  357 rn_dbg_print(void *arg, const char *fmt, ...)
  358 {
  359         va_list ap;
  360 
  361         va_start(ap, fmt);
  362         vlog(LOG_DEBUG, fmt, ap);
  363         va_end(ap);
  364 }
  365 
  366 static void
  367 rn_treeprint(struct radix_node_head *h, rn_printer_t printer, void *arg)
  368 {
  369         struct radix_node *dup, *rn;
  370         const char *delim;
  371 
  372         if (printer == NULL)
  373                 return;
  374 
  375         rn = rn_walkfirst(h->rnh_treetop, printer, arg);
  376         for (;;) {
  377                 /* Process leaves */
  378                 delim = "";
  379                 for (dup = rn; dup != NULL; dup = dup->rn_dupedkey) {
  380                         if ((dup->rn_flags & RNF_ROOT) != 0)
  381                                 continue;
  382                         rn_nodeprint(dup, printer, arg, delim);
  383                         delim = ", ";
  384                 }
  385                 rn = rn_walknext(rn, printer, arg);
  386                 if (rn->rn_flags & RNF_ROOT)
  387                         return;
  388         }
  389         /* NOTREACHED */
  390 }
  391 
  392 #define traverse(__head, __rn)  rn_treeprint((__head), rn_dbg_print, (__rn))
  393 #endif /* RN_DEBUG */
  394 
  395 struct radix_node *
  396 rn_newpair(
  397         const void *v,
  398         int b,
  399         struct radix_node nodes[2])
  400 {
  401         struct radix_node *tt = nodes;
  402         struct radix_node *t = tt + 1;
  403         t->rn_b = b; t->rn_bmask = 0x80 >> (b & 7);
  404         t->rn_l = tt; t->rn_off = b >> 3;
  405         tt->rn_b = -1; tt->rn_key = v; tt->rn_p = t;
  406         tt->rn_flags = t->rn_flags = RNF_ACTIVE;
  407         return t;
  408 }
  409 
  410 struct radix_node *
  411 rn_insert(
  412         const void *v_arg,
  413         struct radix_node_head *head,
  414         int *dupentry,
  415         struct radix_node nodes[2])
  416 {
  417         struct radix_node *top = head->rnh_treetop;
  418         struct radix_node *t = rn_search(v_arg, top);
  419         struct radix_node *tt;
  420         const char *v = v_arg;
  421         int head_off = top->rn_off;
  422         int vlen = *((const u_char *)v);
  423         const char *cp = v + head_off;
  424         int b;
  425         /*
  426          * Find first bit at which v and t->rn_key differ
  427          */
  428     {
  429         const char *cp2 = t->rn_key + head_off;
  430         const char *cplim = v + vlen;
  431         int cmp_res;
  432 
  433         while (cp < cplim)
  434                 if (*cp2++ != *cp++)
  435                         goto on1;
  436         *dupentry = 1;
  437         return t;
  438 on1:
  439         *dupentry = 0;
  440         cmp_res = (cp[-1] ^ cp2[-1]) & 0xff;
  441         for (b = (cp - v) << 3; cmp_res; b--)
  442                 cmp_res >>= 1;
  443     }
  444     {
  445         struct radix_node *p, *x = top;
  446         cp = v;
  447         do {
  448                 p = x;
  449                 if (cp[x->rn_off] & x->rn_bmask)
  450                         x = x->rn_r;
  451                 else x = x->rn_l;
  452         } while (b > (unsigned) x->rn_b); /* x->rn_b < b && x->rn_b >= 0 */
  453 #ifdef RN_DEBUG
  454         if (rn_debug)
  455                 log(LOG_DEBUG, "%s: Going In:\n", __func__), traverse(head, p);
  456 #endif
  457         t = rn_newpair(v_arg, b, nodes); tt = t->rn_l;
  458         if ((cp[p->rn_off] & p->rn_bmask) == 0)
  459                 p->rn_l = t;
  460         else
  461                 p->rn_r = t;
  462         x->rn_p = t; t->rn_p = p; /* frees x, p as temp vars below */
  463         if ((cp[t->rn_off] & t->rn_bmask) == 0) {
  464                 t->rn_r = x;
  465         } else {
  466                 t->rn_r = tt; t->rn_l = x;
  467         }
  468 #ifdef RN_DEBUG
  469         if (rn_debug) {
  470                 log(LOG_DEBUG, "%s: Coming Out:\n", __func__),
  471                     traverse(head, p);
  472         }
  473 #endif /* RN_DEBUG */
  474     }
  475         return tt;
  476 }
  477 
  478 struct radix_node *
  479 rn_addmask(
  480         const void *n_arg,
  481         int search,
  482         int skip)
  483 {
  484         const char *netmask = n_arg;
  485         const char *cp;
  486         const char *cplim;
  487         struct radix_node *x;
  488         struct radix_node *saved_x;
  489         int b = 0, mlen, j;
  490         int maskduplicated, m0, isnormal;
  491         static int last_zeroed = 0;
  492 
  493         if ((mlen = *(const u_char *)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                 memmove(addmask_key + 1, rn_ones + 1, skip - 1);
  501         if ((m0 = mlen) > skip)
  502                 memmove(addmask_key + skip, netmask + 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                 memset(addmask_key + m0, 0, last_zeroed - m0);
  516         *addmask_key = last_zeroed = mlen;
  517         x = rn_search(addmask_key, rn_masktop);
  518         if (memcmp(addmask_key, x->rn_key, mlen) != 0)
  519                 x = 0;
  520         if (x || search)
  521                 return x;
  522         R_Malloc(x, struct radix_node *, max_keylen + 2 * sizeof (*x));
  523         if ((saved_x = x) == NULL)
  524                 return NULL;
  525         memset(x, 0, max_keylen + 2 * sizeof (*x));
  526         cp = netmask = (void *)(x + 2);
  527         memmove(x + 2, addmask_key, mlen);
  528         x = rn_insert(cp, mask_rnhead, &maskduplicated, x);
  529         if (maskduplicated) {
  530                 log(LOG_ERR, "rn_addmask: mask impossibly already in tree\n");
  531                 Free(saved_x);
  532                 return x;
  533         }
  534         /*
  535          * Calculate index of mask, and check for normalcy.
  536          */
  537         cplim = netmask + mlen; isnormal = 1;
  538         for (cp = netmask + skip; (cp < cplim) && *(const u_char *)cp == 0xff;)
  539                 cp++;
  540         if (cp != cplim) {
  541                 for (j = 0x80; (j & *cp) != 0; j >>= 1)
  542                         b++;
  543                 if (*cp != normal_chars[b] || cp != (cplim - 1))
  544                         isnormal = 0;
  545         }
  546         b += (cp - netmask) << 3;
  547         x->rn_b = -1 - b;
  548         if (isnormal)
  549                 x->rn_flags |= RNF_NORMAL;
  550         return x;
  551 }
  552 
  553 static int      /* XXX: arbitrary ordering for non-contiguous masks */
  554 rn_lexobetter(
  555         const void *m_arg,
  556         const void *n_arg)
  557 {
  558         const u_char *mp = m_arg;
  559         const u_char *np = n_arg;
  560         const u_char *lim;
  561 
  562         if (*mp > *np)
  563                 return 1;  /* not really, but need to check longer one first */
  564         if (*mp == *np)
  565                 for (lim = mp + *mp; mp < lim;)
  566                         if (*mp++ > *np++)
  567                                 return 1;
  568         return 0;
  569 }
  570 
  571 static struct radix_mask *
  572 rn_new_radix_mask(
  573         struct radix_node *tt,
  574         struct radix_mask *next)
  575 {
  576         struct radix_mask *m;
  577 
  578         MKGet(m);
  579         if (m == NULL) {
  580                 log(LOG_ERR, "Mask for route not entered\n");
  581                 return NULL;
  582         }
  583         memset(m, 0, sizeof(*m));
  584         m->rm_b = tt->rn_b;
  585         m->rm_flags = tt->rn_flags;
  586         if (tt->rn_flags & RNF_NORMAL)
  587                 m->rm_leaf = tt;
  588         else
  589                 m->rm_mask = tt->rn_mask;
  590         m->rm_mklist = next;
  591         tt->rn_mklist = m;
  592         return m;
  593 }
  594 
  595 struct radix_node *
  596 rn_addroute(
  597         const void *v_arg,
  598         const void *n_arg,
  599         struct radix_node_head *head,
  600         struct radix_node treenodes[2])
  601 {
  602         const char *v = v_arg, *netmask = n_arg;
  603         struct radix_node *t, *x = NULL, *tt;
  604         struct radix_node *saved_tt, *top = head->rnh_treetop;
  605         short b = 0, b_leaf = 0;
  606         int keyduplicated;
  607         const char *mmask;
  608         struct radix_mask *m, **mp;
  609 
  610         /*
  611          * In dealing with non-contiguous masks, there may be
  612          * many different routes which have the same mask.
  613          * We will find it useful to have a unique pointer to
  614          * the mask to speed avoiding duplicate references at
  615          * nodes and possibly save time in calculating indices.
  616          */
  617         if (netmask != NULL) {
  618                 if ((x = rn_addmask(netmask, 0, top->rn_off)) == NULL)
  619                         return NULL;
  620                 b_leaf = x->rn_b;
  621                 b = -1 - x->rn_b;
  622                 netmask = x->rn_key;
  623         }
  624         /*
  625          * Deal with duplicated keys: attach node to previous instance
  626          */
  627         saved_tt = tt = rn_insert(v, head, &keyduplicated, treenodes);
  628         if (keyduplicated) {
  629                 for (t = tt; tt != NULL; t = tt, tt = tt->rn_dupedkey) {
  630                         if (tt->rn_mask == netmask)
  631                                 return NULL;
  632                         if (netmask == NULL ||
  633                             (tt->rn_mask != NULL &&
  634                              (b_leaf < tt->rn_b || /* index(netmask) > node */
  635                                rn_refines(netmask, tt->rn_mask) ||
  636                                rn_lexobetter(netmask, tt->rn_mask))))
  637                                 break;
  638                 }
  639                 /*
  640                  * If the mask is not duplicated, we wouldn't
  641                  * find it among possible duplicate key entries
  642                  * anyway, so the above test doesn't hurt.
  643                  *
  644                  * We sort the masks for a duplicated key the same way as
  645                  * in a masklist -- most specific to least specific.
  646                  * This may require the unfortunate nuisance of relocating
  647                  * the head of the list.
  648                  *
  649                  * We also reverse, or doubly link the list through the
  650                  * parent pointer.
  651                  */
  652                 if (tt == saved_tt) {
  653                         struct  radix_node *xx = x;
  654                         /* link in at head of list */
  655                         (tt = treenodes)->rn_dupedkey = t;
  656                         tt->rn_flags = t->rn_flags;
  657                         tt->rn_p = x = t->rn_p;
  658                         t->rn_p = tt;
  659                         if (x->rn_l == t)
  660                                 x->rn_l = tt;
  661                         else
  662                                 x->rn_r = tt;
  663                         saved_tt = tt;
  664                         x = xx;
  665                 } else {
  666                         (tt = treenodes)->rn_dupedkey = t->rn_dupedkey;
  667                         t->rn_dupedkey = tt;
  668                         tt->rn_p = t;
  669                         if (tt->rn_dupedkey)
  670                                 tt->rn_dupedkey->rn_p = tt;
  671                 }
  672                 tt->rn_key = v;
  673                 tt->rn_b = -1;
  674                 tt->rn_flags = RNF_ACTIVE;
  675         }
  676         /*
  677          * Put mask in tree.
  678          */
  679         if (netmask != NULL) {
  680                 tt->rn_mask = netmask;
  681                 tt->rn_b = x->rn_b;
  682                 tt->rn_flags |= x->rn_flags & RNF_NORMAL;
  683         }
  684         t = saved_tt->rn_p;
  685         if (keyduplicated)
  686                 goto on2;
  687         b_leaf = -1 - t->rn_b;
  688         if (t->rn_r == saved_tt)
  689                 x = t->rn_l;
  690         else
  691                 x = t->rn_r;
  692         /* Promote general routes from below */
  693         if (x->rn_b < 0) {
  694                 for (mp = &t->rn_mklist; x != NULL; x = x->rn_dupedkey) {
  695                         if (x->rn_mask != NULL && x->rn_b >= b_leaf &&
  696                             x->rn_mklist == NULL) {
  697                                 *mp = m = rn_new_radix_mask(x, NULL);
  698                                 if (m != NULL)
  699                                         mp = &m->rm_mklist;
  700                         }
  701                 }
  702         } else if (x->rn_mklist != NULL) {
  703                 /*
  704                  * Skip over masks whose index is > that of new node
  705                  */
  706                 for (mp = &x->rn_mklist; (m = *mp) != NULL; mp = &m->rm_mklist)
  707                         if (m->rm_b >= b_leaf)
  708                                 break;
  709                 t->rn_mklist = m;
  710                 *mp = NULL;
  711         }
  712 on2:
  713         /* Add new route to highest possible ancestor's list */
  714         if (netmask == NULL || b > t->rn_b)
  715                 return tt; /* can't lift at all */
  716         b_leaf = tt->rn_b;
  717         do {
  718                 x = t;
  719                 t = t->rn_p;
  720         } while (b <= t->rn_b && x != top);
  721         /*
  722          * Search through routes associated with node to
  723          * insert new route according to index.
  724          * Need same criteria as when sorting dupedkeys to avoid
  725          * double loop on deletion.
  726          */
  727         for (mp = &x->rn_mklist; (m = *mp) != NULL; mp = &m->rm_mklist) {
  728                 if (m->rm_b < b_leaf)
  729                         continue;
  730                 if (m->rm_b > b_leaf)
  731                         break;
  732                 if (m->rm_flags & RNF_NORMAL) {
  733                         mmask = m->rm_leaf->rn_mask;
  734                         if (tt->rn_flags & RNF_NORMAL) {
  735                                 log(LOG_ERR, "Non-unique normal route,"
  736                                     " mask not entered\n");
  737                                 return tt;
  738                         }
  739                 } else
  740                         mmask = m->rm_mask;
  741                 if (mmask == netmask) {
  742                         m->rm_refs++;
  743                         tt->rn_mklist = m;
  744                         return tt;
  745                 }
  746                 if (rn_refines(netmask, mmask) || rn_lexobetter(netmask, mmask))
  747                         break;
  748         }
  749         *mp = rn_new_radix_mask(tt, *mp);
  750         return tt;
  751 }
  752 
  753 struct radix_node *
  754 rn_delete1(
  755         const void *v_arg,
  756         const void *netmask_arg,
  757         struct radix_node_head *head,
  758         struct radix_node *rn)
  759 {
  760         struct radix_node *t, *p, *x, *tt;
  761         struct radix_mask *m, *saved_m, **mp;
  762         struct radix_node *dupedkey, *saved_tt, *top;
  763         const char *v, *netmask;
  764         int b, head_off, vlen;
  765 
  766         v = v_arg;
  767         netmask = netmask_arg;
  768         x = head->rnh_treetop;
  769         tt = rn_search(v, x);
  770         head_off = x->rn_off;
  771         vlen =  *(const u_char *)v;
  772         saved_tt = tt;
  773         top = x;
  774         if (tt == NULL ||
  775             memcmp(v + head_off, tt->rn_key + head_off, vlen - head_off) != 0)
  776                 return NULL;
  777         /*
  778          * Delete our route from mask lists.
  779          */
  780         if (netmask != NULL) {
  781                 if ((x = rn_addmask(netmask, 1, head_off)) == NULL)
  782                         return NULL;
  783                 netmask = x->rn_key;
  784                 while (tt->rn_mask != netmask)
  785                         if ((tt = tt->rn_dupedkey) == NULL)
  786                                 return NULL;
  787         }
  788         if (tt->rn_mask == NULL || (saved_m = m = tt->rn_mklist) == NULL)
  789                 goto on1;
  790         if (tt->rn_flags & RNF_NORMAL) {
  791                 if (m->rm_leaf != tt || m->rm_refs > 0) {
  792                         log(LOG_ERR, "rn_delete: inconsistent annotation\n");
  793                         return NULL;  /* dangling ref could cause disaster */
  794                 }
  795         } else {
  796                 if (m->rm_mask != tt->rn_mask) {
  797                         log(LOG_ERR, "rn_delete: inconsistent annotation\n");
  798                         goto on1;
  799                 }
  800                 if (--m->rm_refs >= 0)
  801                         goto on1;
  802         }
  803         b = -1 - tt->rn_b;
  804         t = saved_tt->rn_p;
  805         if (b > t->rn_b)
  806                 goto on1; /* Wasn't lifted at all */
  807         do {
  808                 x = t;
  809                 t = t->rn_p;
  810         } while (b <= t->rn_b && x != top);
  811         for (mp = &x->rn_mklist; (m = *mp) != NULL; mp = &m->rm_mklist) {
  812                 if (m == saved_m) {
  813                         *mp = m->rm_mklist;
  814                         MKFree(m);
  815                         break;
  816                 }
  817         }
  818         if (m == NULL) {
  819                 log(LOG_ERR, "rn_delete: couldn't find our annotation\n");
  820                 if (tt->rn_flags & RNF_NORMAL)
  821                         return NULL; /* Dangling ref to us */
  822         }
  823 on1:
  824         /*
  825          * Eliminate us from tree
  826          */
  827         if (tt->rn_flags & RNF_ROOT)
  828                 return NULL;
  829 #ifdef RN_DEBUG
  830         if (rn_debug)
  831                 log(LOG_DEBUG, "%s: Going In:\n", __func__), traverse(head, tt);
  832 #endif
  833         t = tt->rn_p;
  834         dupedkey = saved_tt->rn_dupedkey;
  835         if (dupedkey != NULL) {
  836                 /*
  837                  * Here, tt is the deletion target, and
  838                  * saved_tt is the head of the dupedkey chain.
  839                  */
  840                 if (tt == saved_tt) {
  841                         x = dupedkey;
  842                         x->rn_p = t;
  843                         if (t->rn_l == tt)
  844                                 t->rn_l = x;
  845                         else
  846                                 t->rn_r = x;
  847                 } else {
  848                         /* find node in front of tt on the chain */
  849                         for (x = p = saved_tt;
  850                              p != NULL && p->rn_dupedkey != tt;)
  851                                 p = p->rn_dupedkey;
  852                         if (p != NULL) {
  853                                 p->rn_dupedkey = tt->rn_dupedkey;
  854                                 if (tt->rn_dupedkey != NULL)
  855                                         tt->rn_dupedkey->rn_p = p;
  856                         } else
  857                                 log(LOG_ERR, "rn_delete: couldn't find us\n");
  858                 }
  859                 t = tt + 1;
  860                 if  (t->rn_flags & RNF_ACTIVE) {
  861                         *++x = *t;
  862                         p = t->rn_p;
  863                         if (p->rn_l == t)
  864                                 p->rn_l = x;
  865                         else
  866                                 p->rn_r = x;
  867                         x->rn_l->rn_p = x;
  868                         x->rn_r->rn_p = x;
  869                 }
  870                 goto out;
  871         }
  872         if (t->rn_l == tt)
  873                 x = t->rn_r;
  874         else
  875                 x = t->rn_l;
  876         p = t->rn_p;
  877         if (p->rn_r == t)
  878                 p->rn_r = x;
  879         else
  880                 p->rn_l = x;
  881         x->rn_p = p;
  882         /*
  883          * Demote routes attached to us.
  884          */
  885         if (t->rn_mklist == NULL)
  886                 ;
  887         else if (x->rn_b >= 0) {
  888                 for (mp = &x->rn_mklist; (m = *mp) != NULL; mp = &m->rm_mklist)
  889                         ;
  890                 *mp = t->rn_mklist;
  891         } else {
  892                 /* If there are any key,mask pairs in a sibling
  893                    duped-key chain, some subset will appear sorted
  894                    in the same order attached to our mklist */
  895                 for (m = t->rn_mklist;
  896                      m != NULL && x != NULL;
  897                      x = x->rn_dupedkey) {
  898                         if (m == x->rn_mklist) {
  899                                 struct radix_mask *mm = m->rm_mklist;
  900                                 x->rn_mklist = NULL;
  901                                 if (--(m->rm_refs) < 0)
  902                                         MKFree(m);
  903                                 m = mm;
  904                         }
  905                 }
  906                 if (m != NULL) {
  907                         log(LOG_ERR, "rn_delete: Orphaned Mask %p at %p\n",
  908                             m, x);
  909                 }
  910         }
  911         /*
  912          * We may be holding an active internal node in the tree.
  913          */
  914         x = tt + 1;
  915         if (t != x) {
  916                 *t = *x;
  917                 t->rn_l->rn_p = t;
  918                 t->rn_r->rn_p = t;
  919                 p = x->rn_p;
  920                 if (p->rn_l == x)
  921                         p->rn_l = t;
  922                 else
  923                         p->rn_r = t;
  924         }
  925 out:
  926 #ifdef RN_DEBUG
  927         if (rn_debug) {
  928                 log(LOG_DEBUG, "%s: Coming Out:\n", __func__),
  929                     traverse(head, tt);
  930         }
  931 #endif /* RN_DEBUG */
  932         tt->rn_flags &= ~RNF_ACTIVE;
  933         tt[1].rn_flags &= ~RNF_ACTIVE;
  934         return tt;
  935 }
  936 
  937 struct radix_node *
  938 rn_delete(
  939         const void *v_arg,
  940         const void *netmask_arg,
  941         struct radix_node_head *head)
  942 {
  943         return rn_delete1(v_arg, netmask_arg, head, NULL);
  944 }
  945 
  946 static struct radix_node *
  947 rn_walknext(struct radix_node *rn, rn_printer_t printer, void *arg)
  948 {
  949         /* If at right child go back up, otherwise, go right */
  950         while (rn->rn_p->rn_r == rn && (rn->rn_flags & RNF_ROOT) == 0) {
  951                 if (printer != NULL)
  952                         (*printer)(arg, SUBTREE_CLOSE);
  953                 rn = rn->rn_p;
  954         }
  955         if (printer)
  956                 rn_nodeprint(rn->rn_p, printer, arg, "");
  957         /* Find the next *leaf* since next node might vanish, too */
  958         for (rn = rn->rn_p->rn_r; rn->rn_b >= 0;) {
  959                 if (printer != NULL)
  960                         (*printer)(arg, SUBTREE_OPEN);
  961                 rn = rn->rn_l;
  962         }
  963         return rn;
  964 }
  965 
  966 static struct radix_node *
  967 rn_walkfirst(struct radix_node *rn, rn_printer_t printer, void *arg)
  968 {
  969         /* First time through node, go left */
  970         while (rn->rn_b >= 0) {
  971                 if (printer != NULL)
  972                         (*printer)(arg, SUBTREE_OPEN);
  973                 rn = rn->rn_l;
  974         }
  975         return rn;
  976 }
  977 
  978 int
  979 rn_walktree(
  980         struct radix_node_head *h,
  981         int (*f)(struct radix_node *, void *),
  982         void *w)
  983 {
  984         int error;
  985         struct radix_node *base, *next, *rn;
  986         /*
  987          * This gets complicated because we may delete the node
  988          * while applying the function f to it, so we need to calculate
  989          * the successor node in advance.
  990          */
  991         rn = rn_walkfirst(h->rnh_treetop, NULL, NULL);
  992         for (;;) {
  993                 base = rn;
  994                 next = rn_walknext(rn, NULL, NULL);
  995                 /* Process leaves */
  996                 while ((rn = base) != NULL) {
  997                         base = rn->rn_dupedkey;
  998                         if (!(rn->rn_flags & RNF_ROOT) && (error = (*f)(rn, w)))
  999                                 return error;
 1000                 }
 1001                 rn = next;
 1002                 if (rn->rn_flags & RNF_ROOT)
 1003                         return 0;
 1004         }
 1005         /* NOTREACHED */
 1006 }
 1007 
 1008 struct radix_node *
 1009 rn_search_matched(struct radix_node_head *h,
 1010     int (*matcher)(struct radix_node *, void *), void *w)
 1011 {
 1012         bool matched;
 1013         struct radix_node *base, *next, *rn;
 1014         /*
 1015          * This gets complicated because we may delete the node
 1016          * while applying the function f to it, so we need to calculate
 1017          * the successor node in advance.
 1018          */
 1019         rn = rn_walkfirst(h->rnh_treetop, NULL, NULL);
 1020         for (;;) {
 1021                 base = rn;
 1022                 next = rn_walknext(rn, NULL, NULL);
 1023                 /* Process leaves */
 1024                 while ((rn = base) != NULL) {
 1025                         base = rn->rn_dupedkey;
 1026                         if (!(rn->rn_flags & RNF_ROOT)) {
 1027                                 matched = (*matcher)(rn, w);
 1028                                 if (matched)
 1029                                         return rn;
 1030                         }
 1031                 }
 1032                 rn = next;
 1033                 if (rn->rn_flags & RNF_ROOT)
 1034                         return NULL;
 1035         }
 1036         /* NOTREACHED */
 1037 }
 1038 
 1039 struct delayinit {
 1040         void **head;
 1041         int off;
 1042         SLIST_ENTRY(delayinit) entries;
 1043 };
 1044 static SLIST_HEAD(, delayinit) delayinits = SLIST_HEAD_INITIALIZER(delayheads);
 1045 static int radix_initialized;
 1046 
 1047 /*
 1048  * Initialize a radix tree once radix is initialized.  Only for bootstrap.
 1049  * Assume that no concurrency protection is necessary at this stage.
 1050  */
 1051 void
 1052 rn_delayedinit(void **head, int off)
 1053 {
 1054         struct delayinit *di;
 1055 
 1056         if (radix_initialized)
 1057                 return;
 1058 
 1059         di = kmem_alloc(sizeof(*di), KM_SLEEP);
 1060         di->head = head;
 1061         di->off = off;
 1062         SLIST_INSERT_HEAD(&delayinits, di, entries);
 1063 }
 1064 
 1065 int
 1066 rn_inithead(void **head, int off)
 1067 {
 1068         struct radix_node_head *rnh;
 1069 
 1070         if (*head != NULL)
 1071                 return 1;
 1072         R_Malloc(rnh, struct radix_node_head *, sizeof (*rnh));
 1073         if (rnh == NULL)
 1074                 return 0;
 1075         *head = rnh;
 1076         return rn_inithead0(rnh, off);
 1077 }
 1078 
 1079 int
 1080 rn_inithead0(struct radix_node_head *rnh, int off)
 1081 {
 1082         struct radix_node *t;
 1083         struct radix_node *tt;
 1084         struct radix_node *ttt;
 1085 
 1086         memset(rnh, 0, sizeof(*rnh));
 1087         t = rn_newpair(rn_zeros, off, rnh->rnh_nodes);
 1088         ttt = rnh->rnh_nodes + 2;
 1089         t->rn_r = ttt;
 1090         t->rn_p = t;
 1091         tt = t->rn_l;
 1092         tt->rn_flags = t->rn_flags = RNF_ROOT | RNF_ACTIVE;
 1093         tt->rn_b = -1 - off;
 1094         *ttt = *tt;
 1095         ttt->rn_key = rn_ones;
 1096         rnh->rnh_addaddr = rn_addroute;
 1097         rnh->rnh_deladdr = rn_delete;
 1098         rnh->rnh_matchaddr = rn_match;
 1099         rnh->rnh_lookup = rn_lookup;
 1100         rnh->rnh_treetop = t;
 1101         return 1;
 1102 }
 1103 
 1104 void
 1105 rn_init(void)
 1106 {
 1107         char *cp, *cplim;
 1108         struct delayinit *di;
 1109 #ifdef _KERNEL
 1110         struct domain *dp;
 1111 
 1112         if (radix_initialized)
 1113                 panic("radix already initialized");
 1114         radix_initialized = 1;
 1115 
 1116         DOMAIN_FOREACH(dp) {
 1117                 if (dp->dom_maxrtkey > max_keylen)
 1118                         max_keylen = dp->dom_maxrtkey;
 1119         }
 1120 #endif
 1121         if (max_keylen == 0) {
 1122 #ifndef _KERNEL
 1123                 log(LOG_ERR,
 1124                     "rn_init: radix functions require max_keylen be set\n");
 1125 #endif
 1126                 return;
 1127         }
 1128 
 1129         R_Malloc(rn_zeros, char *, 3 * max_keylen);
 1130         if (rn_zeros == NULL)
 1131                 panic("rn_init");
 1132         memset(rn_zeros, 0, 3 * max_keylen);
 1133         rn_ones = cp = rn_zeros + max_keylen;
 1134         addmask_key = cplim = rn_ones + max_keylen;
 1135         while (cp < cplim)
 1136                 *cp++ = -1;
 1137         if (rn_inithead((void *)&mask_rnhead, 0) == 0)
 1138                 panic("rn_init 2");
 1139 
 1140         while ((di = SLIST_FIRST(&delayinits)) != NULL) {
 1141                 if (!rn_inithead(di->head, di->off))
 1142                         panic("delayed rn_inithead failed");
 1143                 SLIST_REMOVE_HEAD(&delayinits, entries);
 1144                 kmem_free(di, sizeof(*di));
 1145         }
 1146 }

Cache object: 632ea0284b5a6454243c40f584692bb5


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