From 20f13d8bcf58854c0416942f7c7975ace2e92d65 Mon Sep 17 00:00:00 2001 From: wollman Date: Sun, 23 Apr 2000 04:00:00 +0000 Subject: A couple months ago, Kirk and I were doing a walkthrough of the radix-tree search routine, and scratching our heads over why it was so obfuscated. This delta fixes a number of confusing style bugs and renames several structure members to have more meaningful names. There remain a number of odd control-flow structures. These changes do not affect the generated code. --- sys/net/radix.c | 335 ++++++++++++++++++++++++++++++++------------------------ 1 file changed, 190 insertions(+), 145 deletions(-) (limited to 'sys/net/radix.c') diff --git a/sys/net/radix.c b/sys/net/radix.c index 9dbbf97..e5bc935 100644 --- a/sys/net/radix.c +++ b/sys/net/radix.c @@ -70,7 +70,8 @@ static char *rn_zeros, *rn_ones; #define rn_masktop (mask_rnhead->rnh_treetop) #undef Bcmp -#define Bcmp(a, b, l) (l == 0 ? 0 : bcmp((caddr_t)(a), (caddr_t)(b), (u_long)l)) +#define Bcmp(a, b, l) \ + (l == 0 ? 0 : bcmp((caddr_t)(a), (caddr_t)(b), (u_long)l)) static int rn_lexobetter __P((void *m_arg, void *n_arg)); static struct radix_mask * @@ -81,12 +82,12 @@ static int rn_satsifies_leaf __P((char *trial, struct radix_node *leaf, /* * The data structure for the keys is a radix tree with one way - * branching removed. The index rn_b at an internal node n represents a bit + * branching removed. The index rn_bit at an internal node n represents a bit * position to be tested. The tree is arranged so that all descendants - * of a node n have keys whose bits all agree up to position rn_b - 1. - * (We say the index of n is rn_b.) + * of a node n have keys whose bits all agree up to position rn_bit - 1. + * (We say the index of n is rn_bit.) * - * There is at least one descendant which has a one bit at position rn_b, + * There is at least one descendant which has a one bit at position rn_bit, * and at least one with a zero there. * * A route is determined by a pair of key and mask. We require that the @@ -96,9 +97,9 @@ static int rn_satsifies_leaf __P((char *trial, struct radix_node *leaf, * representing the highest order bit). * * We say a mask is normal if every bit is 0, past the index of the mask. - * If a node n has a descendant (k, m) with index(m) == index(n) == rn_b, + * If a node n has a descendant (k, m) with index(m) == index(n) == rn_bit, * and m is a normal mask, then the route applies to every descendant of n. - * If the index(m) < rn_b, this implies the trailing last few bits of k + * If the index(m) < rn_bit, this implies the trailing last few bits of k * before bit b are all 0, (and hence consequently true of every descendant * of n), so the route applies to all descendants of the node as well. * @@ -121,11 +122,11 @@ rn_search(v_arg, head) register struct radix_node *x; register caddr_t v; - for (x = head, v = v_arg; x->rn_b >= 0;) { - if (x->rn_bmask & v[x->rn_off]) - x = x->rn_r; + for (x = head, v = v_arg; x->rn_bit >= 0;) { + if (x->rn_bmask & v[x->rn_offset]) + x = x->rn_right; else - x = x->rn_l; + x = x->rn_left; } return (x); } @@ -138,12 +139,12 @@ rn_search_m(v_arg, head, m_arg) register struct radix_node *x; register caddr_t v = v_arg, m = m_arg; - for (x = head; x->rn_b >= 0;) { - if ((x->rn_bmask & m[x->rn_off]) && - (x->rn_bmask & v[x->rn_off])) - x = x->rn_r; + for (x = head; x->rn_bit >= 0;) { + if ((x->rn_bmask & m[x->rn_offset]) && + (x->rn_bmask & v[x->rn_offset])) + x = x->rn_right; else - x = x->rn_l; + x = x->rn_left; } return x; } @@ -184,7 +185,8 @@ rn_lookup(v_arg, m_arg, head) caddr_t netmask = 0; if (m_arg) { - if ((x = rn_addmask(m_arg, 1, head->rnh_treetop->rn_off)) == 0) + x = rn_addmask(m_arg, 1, head->rnh_treetop->rn_offset); + if (x == 0) return (0); netmask = x->rn_key; } @@ -227,18 +229,18 @@ rn_match(v_arg, head) register caddr_t cp = v, cp2; caddr_t cplim; struct radix_node *saved_t, *top = t; - int off = t->rn_off, vlen = *(u_char *)cp, matched_off; - register int test, b, rn_b; + int off = t->rn_offset, vlen = *(u_char *)cp, matched_off; + register int test, b, rn_bit; /* * Open code rn_search(v, top) to avoid overhead of extra * subroutine call. */ - for (; t->rn_b >= 0; ) { - if (t->rn_bmask & cp[t->rn_off]) - t = t->rn_r; + for (; t->rn_bit >= 0; ) { + if (t->rn_bmask & cp[t->rn_offset]) + t = t->rn_right; else - t = t->rn_l; + t = t->rn_left; } /* * See if we match exactly as a host destination @@ -273,7 +275,7 @@ on1: b--; matched_off = cp - v; b += matched_off << 3; - rn_b = -1 - b; + rn_bit = -1 - b; /* * If there is a host route in a duped-key chain, it will be first. */ @@ -286,7 +288,7 @@ on1: * a route to a net. */ if (t->rn_flags & RNF_NORMAL) { - if (rn_b <= t->rn_b) + if (rn_bit <= t->rn_bit) return t; } else if (rn_satsifies_leaf(v, t, matched_off)) return t; @@ -294,29 +296,27 @@ on1: /* start searching up the tree */ do { register struct radix_mask *m; - t = t->rn_p; + t = t->rn_parent; m = t->rn_mklist; - if (m) { - /* - * If non-contiguous masks ever become important - * we can restore the masking and open coding of - * the search and satisfaction test and put the - * calculation of "off" back before the "do". - */ - do { - if (m->rm_flags & RNF_NORMAL) { - if (rn_b <= m->rm_b) - return (m->rm_leaf); - } else { - off = min(t->rn_off, matched_off); - x = rn_search_m(v, t, m->rm_mask); - while (x && x->rn_mask != m->rm_mask) - x = x->rn_dupedkey; - if (x && rn_satsifies_leaf(v, x, off)) - return x; - } - m = m->rm_mklist; - } while (m); + /* + * If non-contiguous masks ever become important + * we can restore the masking and open coding of + * the search and satisfaction test and put the + * calculation of "off" back before the "do". + */ + while (m) { + if (m->rm_flags & RNF_NORMAL) { + if (rn_bit <= m->rm_bit) + return (m->rm_leaf); + } else { + off = min(t->rn_offset, matched_off); + x = rn_search_m(v, t, m->rm_mask); + while (x && x->rn_mask != m->rm_mask) + x = x->rn_dupedkey; + if (x && rn_satsifies_leaf(v, x, off)) + return x; + } + m = m->rm_mklist; } } while (t != top); return 0; @@ -336,13 +336,19 @@ rn_newpair(v, b, nodes) struct radix_node nodes[2]; { register struct radix_node *tt = nodes, *t = tt + 1; - t->rn_b = b; t->rn_bmask = 0x80 >> (b & 7); - t->rn_l = tt; t->rn_off = b >> 3; - tt->rn_b = -1; tt->rn_key = (caddr_t)v; tt->rn_p = t; + t->rn_bit = b; + t->rn_bmask = 0x80 >> (b & 7); + t->rn_left = tt; + t->rn_offset = b >> 3; + tt->rn_bit = -1; + tt->rn_key = (caddr_t)v; + tt->rn_parent = t; tt->rn_flags = t->rn_flags = RNF_ACTIVE; #ifdef RN_DEBUG tt->rn_info = rn_nodenum++; t->rn_info = rn_nodenum++; - tt->rn_twin = t; tt->rn_ybro = rn_clist; rn_clist = tt; + tt->rn_twin = t; + tt->rn_ybro = rn_clist; + rn_clist = tt; #endif return t; } @@ -356,7 +362,7 @@ rn_insert(v_arg, head, dupentry, nodes) { caddr_t v = v_arg; struct radix_node *top = head->rnh_treetop; - int head_off = top->rn_off, vlen = (int)*((u_char *)v); + int head_off = top->rn_offset, vlen = (int)*((u_char *)v); register struct radix_node *t = rn_search(v_arg, top); register caddr_t cp = v + head_off; register int b; @@ -385,24 +391,29 @@ on1: cp = v; do { p = x; - if (cp[x->rn_off] & x->rn_bmask) - x = x->rn_r; - else x = x->rn_l; - } while (b > (unsigned) x->rn_b); /* x->rn_b < b && x->rn_b >= 0 */ + if (cp[x->rn_offset] & x->rn_bmask) + x = x->rn_right; + else + x = x->rn_left; + } while (b > (unsigned) x->rn_bit); + /* x->rn_bit < b && x->rn_bit >= 0 */ #ifdef RN_DEBUG if (rn_debug) log(LOG_DEBUG, "rn_insert: Going In:\n"), traverse(p); #endif - t = rn_newpair(v_arg, b, nodes); tt = t->rn_l; - if ((cp[p->rn_off] & p->rn_bmask) == 0) - p->rn_l = t; + t = rn_newpair(v_arg, b, nodes); + tt = t->rn_left; + if ((cp[p->rn_offset] & p->rn_bmask) == 0) + p->rn_left = t; else - p->rn_r = t; - x->rn_p = t; t->rn_p = p; /* frees x, p as temp vars below */ - if ((cp[t->rn_off] & t->rn_bmask) == 0) { - t->rn_r = x; + p->rn_right = t; + x->rn_parent = t; + t->rn_parent = p; /* frees x, p as temp vars below */ + if ((cp[t->rn_offset] & t->rn_bmask) == 0) { + t->rn_right = x; } else { - t->rn_r = tt; t->rn_l = x; + t->rn_right = tt; + t->rn_left = x; } #ifdef RN_DEBUG if (rn_debug) @@ -479,7 +490,7 @@ rn_addmask(n_arg, search, skip) isnormal = 0; } b += (cp - netmask) << 3; - x->rn_b = -1 - b; + x->rn_bit = -1 - b; if (isnormal) x->rn_flags |= RNF_NORMAL; return (x); @@ -513,7 +524,7 @@ rn_new_radix_mask(tt, next) return (0); } Bzero(m, sizeof *m); - m->rm_b = tt->rn_b; + m->rm_bit = tt->rn_bit; m->rm_flags = tt->rn_flags; if (tt->rn_flags & RNF_NORMAL) m->rm_leaf = tt; @@ -546,10 +557,10 @@ rn_addroute(v_arg, n_arg, head, treenodes) * nodes and possibly save time in calculating indices. */ if (netmask) { - if ((x = rn_addmask(netmask, 0, top->rn_off)) == 0) + if ((x = rn_addmask(netmask, 0, top->rn_offset)) == 0) return (0); - b_leaf = x->rn_b; - b = -1 - x->rn_b; + b_leaf = x->rn_bit; + b = -1 - x->rn_bit; netmask = x->rn_key; } /* @@ -562,9 +573,9 @@ rn_addroute(v_arg, n_arg, head, treenodes) return (0); if (netmask == 0 || (tt->rn_mask && - ((b_leaf < tt->rn_b) || /* index(netmask) > node */ - rn_refines(netmask, tt->rn_mask) || - rn_lexobetter(netmask, tt->rn_mask)))) + ((b_leaf < tt->rn_bit) /* index(netmask) > node */ + || rn_refines(netmask, tt->rn_mask) + || rn_lexobetter(netmask, tt->rn_mask)))) break; } /* @@ -582,23 +593,26 @@ rn_addroute(v_arg, n_arg, head, treenodes) /* link in at head of list */ (tt = treenodes)->rn_dupedkey = t; tt->rn_flags = t->rn_flags; - tt->rn_p = x = t->rn_p; - t->rn_p = tt; /* parent */ - if (x->rn_l == t) x->rn_l = tt; else x->rn_r = tt; + tt->rn_parent = x = t->rn_parent; + t->rn_parent = tt; /* parent */ + if (x->rn_left == t) + x->rn_left = tt; + else + x->rn_right = tt; saved_tt = tt; x = xx; } else { (tt = treenodes)->rn_dupedkey = t->rn_dupedkey; t->rn_dupedkey = tt; - tt->rn_p = t; /* parent */ + tt->rn_parent = t; /* parent */ if (tt->rn_dupedkey) /* parent */ - tt->rn_dupedkey->rn_p = tt; /* parent */ + tt->rn_dupedkey->rn_parent = tt; /* parent */ } #ifdef RN_DEBUG t=tt+1; tt->rn_info = rn_nodenum++; t->rn_info = rn_nodenum++; tt->rn_twin = t; tt->rn_ybro = rn_clist; rn_clist = tt; #endif tt->rn_key = (caddr_t) v; - tt->rn_b = -1; + tt->rn_bit = -1; tt->rn_flags = RNF_ACTIVE; } /* @@ -606,18 +620,21 @@ rn_addroute(v_arg, n_arg, head, treenodes) */ if (netmask) { tt->rn_mask = netmask; - tt->rn_b = x->rn_b; + tt->rn_bit = x->rn_bit; tt->rn_flags |= x->rn_flags & RNF_NORMAL; } - t = saved_tt->rn_p; + t = saved_tt->rn_parent; if (keyduplicated) goto on2; - b_leaf = -1 - t->rn_b; - if (t->rn_r == saved_tt) x = t->rn_l; else x = t->rn_r; + b_leaf = -1 - t->rn_bit; + if (t->rn_right == saved_tt) + x = t->rn_left; + else + x = t->rn_right; /* Promote general routes from below */ - if (x->rn_b < 0) { + if (x->rn_bit < 0) { for (mp = &t->rn_mklist; x; x = x->rn_dupedkey) - if (x->rn_mask && (x->rn_b >= b_leaf) && x->rn_mklist == 0) { + if (x->rn_mask && (x->rn_bit >= b_leaf) && x->rn_mklist == 0) { *mp = m = rn_new_radix_mask(x, 0); if (m) mp = &m->rm_mklist; @@ -627,19 +644,19 @@ rn_addroute(v_arg, n_arg, head, treenodes) * Skip over masks whose index is > that of new node */ for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist) - if (m->rm_b >= b_leaf) + if (m->rm_bit >= b_leaf) break; t->rn_mklist = m; *mp = 0; } on2: /* Add new route to highest possible ancestor's list */ - if ((netmask == 0) || (b > t->rn_b )) + if ((netmask == 0) || (b > t->rn_bit )) return tt; /* can't lift at all */ - b_leaf = tt->rn_b; + b_leaf = tt->rn_bit; do { x = t; - t = t->rn_p; - } while (b <= t->rn_b && x != top); + t = t->rn_parent; + } while (b <= t->rn_bit && x != top); /* * Search through routes associated with node to * insert new route according to index. @@ -647,15 +664,15 @@ on2: * double loop on deletion. */ for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist) { - if (m->rm_b < b_leaf) + if (m->rm_bit < b_leaf) continue; - if (m->rm_b > b_leaf) + if (m->rm_bit > b_leaf) break; if (m->rm_flags & RNF_NORMAL) { mmask = m->rm_leaf->rn_mask; if (tt->rn_flags & RNF_NORMAL) { - log(LOG_ERR, - "Non-unique normal route, mask not entered"); + log(LOG_ERR, + "Non-unique normal route, mask not entered"); return tt; } } else @@ -665,7 +682,8 @@ on2: tt->rn_mklist = m; return tt; } - if (rn_refines(netmask, mmask) || rn_lexobetter(netmask, mmask)) + if (rn_refines(netmask, mmask) + || rn_lexobetter(netmask, mmask)) break; } *mp = rn_new_radix_mask(tt, *mp); @@ -687,7 +705,7 @@ rn_delete(v_arg, netmask_arg, head) netmask = netmask_arg; x = head->rnh_treetop; tt = rn_search(v, x); - head_off = x->rn_off; + head_off = x->rn_offset; vlen = *(u_char *)v; saved_tt = tt; top = x; @@ -720,14 +738,14 @@ rn_delete(v_arg, netmask_arg, head) if (--m->rm_refs >= 0) goto on1; } - b = -1 - tt->rn_b; - t = saved_tt->rn_p; - if (b > t->rn_b) + b = -1 - tt->rn_bit; + t = saved_tt->rn_parent; + if (b > t->rn_bit) goto on1; /* Wasn't lifted at all */ do { x = t; - t = t->rn_p; - } while (b <= t->rn_b && x != top); + t = t->rn_parent; + } while (b <= t->rn_bit && x != top); for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist) if (m == saved_m) { *mp = m->rm_mklist; @@ -750,7 +768,7 @@ on1: for (t = rn_clist; t && t->rn_ybro != tt; t = t->rn_ybro) {} if (t) t->rn_ybro = tt->rn_ybro; #endif - t = tt->rn_p; + t = tt->rn_parent; dupedkey = saved_tt->rn_dupedkey; if (dupedkey) { /* @@ -759,39 +777,57 @@ on1: */ if (tt == saved_tt) { /* remove from head of chain */ - x = dupedkey; x->rn_p = t; - if (t->rn_l == tt) t->rn_l = x; else t->rn_r = x; + x = dupedkey; x->rn_parent = t; + if (t->rn_left == tt) + t->rn_left = x; + else + t->rn_right = x; } else { /* find node in front of tt on the chain */ for (x = p = saved_tt; p && p->rn_dupedkey != tt;) p = p->rn_dupedkey; if (p) { p->rn_dupedkey = tt->rn_dupedkey; - if (tt->rn_dupedkey) /* parent */ - tt->rn_dupedkey->rn_p = p; /* parent */ + if (tt->rn_dupedkey) /* parent */ + tt->rn_dupedkey->rn_parent = p; + /* parent */ } else log(LOG_ERR, "rn_delete: couldn't find us\n"); } t = tt + 1; if (t->rn_flags & RNF_ACTIVE) { #ifndef RN_DEBUG - *++x = *t; p = t->rn_p; + *++x = *t; + p = t->rn_parent; #else - b = t->rn_info; *++x = *t; t->rn_info = b; p = t->rn_p; + b = t->rn_info; + *++x = *t; + t->rn_info = b; + p = t->rn_parent; #endif - if (p->rn_l == t) p->rn_l = x; else p->rn_r = x; - x->rn_l->rn_p = x; x->rn_r->rn_p = x; + if (p->rn_left == t) + p->rn_left = x; + else + p->rn_right = x; + x->rn_left->rn_parent = x; + x->rn_right->rn_parent = x; } goto out; } - if (t->rn_l == tt) x = t->rn_r; else x = t->rn_l; - p = t->rn_p; - if (p->rn_r == t) p->rn_r = x; else p->rn_l = x; - x->rn_p = p; + if (t->rn_left == tt) + x = t->rn_right; + else + x = t->rn_left; + p = t->rn_parent; + if (p->rn_right == t) + p->rn_right = x; + else + p->rn_left = x; + x->rn_parent = p; /* * Demote routes attached to us. */ if (t->rn_mklist) { - if (x->rn_b >= 0) { + if (x->rn_bit >= 0) { for (mp = &x->rn_mklist; (m = *mp);) mp = &m->rm_mklist; *mp = t->rn_mklist; @@ -821,11 +857,17 @@ on1: #ifndef RN_DEBUG *t = *x; #else - b = t->rn_info; *t = *x; t->rn_info = b; + b = t->rn_info; + *t = *x; + t->rn_info = b; #endif - t->rn_l->rn_p = t; t->rn_r->rn_p = t; - p = x->rn_p; - if (p->rn_l == x) p->rn_l = t; else p->rn_r = t; + t->rn_left->rn_parent = t; + t->rn_right->rn_parent = t; + p = x->rn_parent; + if (p->rn_left == x) + p->rn_left = t; + else + p->rn_right = t; } out: tt->rn_flags &= ~RNF_ACTIVE; @@ -856,17 +898,17 @@ rn_walktree_from(h, a, m, f, w) * rn_search_m is sort-of-open-coded here. */ /* printf("about to search\n"); */ - for (rn = h->rnh_treetop; rn->rn_b >= 0; ) { + for (rn = h->rnh_treetop; rn->rn_bit >= 0; ) { last = rn; - /* printf("rn_b %d, rn_bmask %x, xm[rn_off] %x\n", - rn->rn_b, rn->rn_bmask, xm[rn->rn_off]); */ - if (!(rn->rn_bmask & xm[rn->rn_off])) { + /* printf("rn_bit %d, rn_bmask %x, xm[rn_offset] %x\n", + rn->rn_bit, rn->rn_bmask, xm[rn->rn_offset]); */ + if (!(rn->rn_bmask & xm[rn->rn_offset])) { break; } - if (rn->rn_bmask & xa[rn->rn_off]) { - rn = rn->rn_r; + if (rn->rn_bmask & xa[rn->rn_offset]) { + rn = rn->rn_right; } else { - rn = rn->rn_l; + rn = rn->rn_left; } } /* printf("done searching\n"); */ @@ -878,7 +920,7 @@ rn_walktree_from(h, a, m, f, w) * Either way, last is the node we want to start from. */ rn = last; - lastb = rn->rn_b; + lastb = rn->rn_bit; /* printf("rn %p, lastb %d\n", rn, lastb);*/ @@ -887,26 +929,27 @@ rn_walktree_from(h, a, m, f, w) * while applying the function f to it, so we need to calculate * the successor node in advance. */ - while (rn->rn_b >= 0) - rn = rn->rn_l; + while (rn->rn_bit >= 0) + rn = rn->rn_left; while (!stopping) { - /* printf("node %p (%d)\n", rn, rn->rn_b); */ + /* printf("node %p (%d)\n", rn, rn->rn_bit); */ base = rn; /* If at right child go back up, otherwise, go right */ - while (rn->rn_p->rn_r == rn && !(rn->rn_flags & RNF_ROOT)) { - rn = rn->rn_p; + while (rn->rn_parent->rn_right == rn + && !(rn->rn_flags & RNF_ROOT)) { + rn = rn->rn_parent; /* if went up beyond last, stop */ - if (rn->rn_b < lastb) { + if (rn->rn_bit < lastb) { stopping = 1; /* printf("up too far\n"); */ } } /* Find the next *leaf* since next node might vanish, too */ - for (rn = rn->rn_p->rn_r; rn->rn_b >= 0;) - rn = rn->rn_l; + for (rn = rn->rn_parent->rn_right; rn->rn_bit >= 0;) + rn = rn->rn_left; next = rn; /* Process leaves */ while ((rn = base) != 0) { @@ -942,21 +985,23 @@ rn_walktree(h, f, w) * the successor node in advance. */ /* First time through node, go left */ - while (rn->rn_b >= 0) - rn = rn->rn_l; + while (rn->rn_bit >= 0) + rn = rn->rn_left; for (;;) { base = rn; /* If at right child go back up, otherwise, go right */ - while (rn->rn_p->rn_r == rn && (rn->rn_flags & RNF_ROOT) == 0) - rn = rn->rn_p; + while (rn->rn_parent->rn_right == rn + && (rn->rn_flags & RNF_ROOT) == 0) + rn = rn->rn_parent; /* Find the next *leaf* since next node might vanish, too */ - for (rn = rn->rn_p->rn_r; rn->rn_b >= 0;) - rn = rn->rn_l; + for (rn = rn->rn_parent->rn_right; rn->rn_bit >= 0;) + rn = rn->rn_left; next = rn; /* Process leaves */ while ((rn = base)) { base = rn->rn_dupedkey; - if (!(rn->rn_flags & RNF_ROOT) && (error = (*f)(rn, w))) + if (!(rn->rn_flags & RNF_ROOT) + && (error = (*f)(rn, w))) return (error); } rn = next; @@ -982,11 +1027,11 @@ rn_inithead(head, off) *head = rnh; t = rn_newpair(rn_zeros, off, rnh->rnh_nodes); ttt = rnh->rnh_nodes + 2; - t->rn_r = ttt; - t->rn_p = t; - tt = t->rn_l; + t->rn_right = ttt; + t->rn_parent = t; + tt = t->rn_left; tt->rn_flags = t->rn_flags = RNF_ROOT | RNF_ACTIVE; - tt->rn_b = -1 - off; + tt->rn_bit = -1 - off; *ttt = *tt; ttt->rn_key = rn_ones; rnh->rnh_addaddr = rn_addroute; -- cgit v1.1