From 7f0d245a5e6d2d789e1fce4b5388ea69aba3b428 Mon Sep 17 00:00:00 2001 From: Ondrej Zajicek Date: Tue, 27 Jul 2010 17:17:11 +0200 Subject: Minor changes in prefix trie. --- filter/trie.c | 94 ++++++++++++++++++++++++++++------------------------------- 1 file changed, 45 insertions(+), 49 deletions(-) (limited to 'filter/trie.c') diff --git a/filter/trie.c b/filter/trie.c index fb405de..522eb99 100644 --- a/filter/trie.c +++ b/filter/trie.c @@ -14,7 +14,7 @@ * indicates the index of the bit in the address that is used to * branch at the node. If we need to represent just a set of * prefixes, it would be simple, but we have to represent a - * set of prefix pattern. Each prefix pattern consists of + * set of prefix patterns. Each prefix pattern consists of * &ppaddr/&pplen and two integers: &low and &high, and a prefix * &paddr/&plen matches that pattern if the first MIN(&plen, &pplen) * bits of &paddr and &ppaddr are the same and &low <= &plen <= &high. @@ -65,8 +65,8 @@ * - we are beyond the end of path (node length > &plen) * - we are still on path and keep walking (node length < &plen) * - * The walking code in add_node_to_trie() and trie_match_prefix() - * is structured according to these cases. + * The walking code in trie_match_prefix() is structured according to + * these cases. */ #include "nest/bird.h" @@ -80,17 +80,18 @@ * Allocates and returns a new empty trie. */ struct f_trie * -f_new_trie(void) +f_new_trie(linpool *lp) { struct f_trie * ret; - ret = cfg_allocz(sizeof(struct f_trie)); + ret = lp_allocz(lp, sizeof(struct f_trie)); + ret->lp = lp; return ret; } static inline struct f_trie_node * -new_node(int plen, ip_addr paddr, ip_addr pmask, ip_addr amask) +new_node(struct f_trie *t, int plen, ip_addr paddr, ip_addr pmask, ip_addr amask) { - struct f_trie_node *n = cfg_allocz(sizeof(struct f_trie_node)); + struct f_trie_node *n = lp_allocz(t->lp, sizeof(struct f_trie_node)); n->plen = plen; n->addr = paddr; n->mask = pmask; @@ -104,11 +105,33 @@ attach_node(struct f_trie_node *parent, struct f_trie_node *child) parent->c[ipa_getbit(child->addr, parent->plen) ? 1 : 0] = child; } -static void -add_node_to_trie(struct f_trie *t, int plen, ip_addr ip, ip_addr amask) +/** + * trie_add_prefix + * @t: trie to add to + * @px: prefix address + * @plen: prefix length + * @l: prefix lower bound + * @h: prefix upper bound + * + * Adds prefix (prefix pattern) @px/@plen to trie @t. @l and @h are lower + * and upper bounds on accepted prefix lengths, both inclusive. 0 <= + * l, h <= 32 (128 for IPv6). + */ + +void +trie_add_prefix(struct f_trie *t, ip_addr px, int plen, int l, int h) { + if (l == 0) + t->zero = 1; + else + l--; + + if (h < plen) + plen = h; + + ip_addr amask = ipa_xor(ipa_mkmask(l), ipa_mkmask(h)); ip_addr pmask = ipa_mkmask(plen); - ip_addr paddr = ipa_and(ip, pmask); + ip_addr paddr = ipa_and(px, pmask); struct f_trie_node *o = NULL; struct f_trie_node *n = &t->root; @@ -123,13 +146,13 @@ add_node_to_trie(struct f_trie *t, int plen, ip_addr ip, ip_addr amask) as the other child of 'b'. */ int blen = ipa_pxlen(paddr, n->addr); ip_addr bmask = ipa_mkmask(blen); - ip_addr baddr = ipa_and(ip, bmask); + ip_addr baddr = ipa_and(px, bmask); /* Merge accept masks from children to get accept mask for node 'b' */ ip_addr baccm = ipa_and(ipa_or(amask, n->accept), bmask); - struct f_trie_node *a = new_node(plen, paddr, pmask, amask); - struct f_trie_node *b = new_node(blen, baddr, bmask, baccm); + struct f_trie_node *a = new_node(t, plen, paddr, pmask, amask); + struct f_trie_node *b = new_node(t, blen, baddr, bmask, baccm); attach_node(o, b); attach_node(b, n); attach_node(b, a); @@ -140,7 +163,7 @@ add_node_to_trie(struct f_trie *t, int plen, ip_addr ip, ip_addr amask) { /* We add new node 'a' between node 'o' and node 'n' */ amask = ipa_or(amask, ipa_and(n->accept, pmask)); - struct f_trie_node *a = new_node(plen, paddr, pmask, amask); + struct f_trie_node *a = new_node(t, plen, paddr, pmask, amask); attach_node(o, a); attach_node(a, n); return; @@ -156,58 +179,31 @@ add_node_to_trie(struct f_trie *t, int plen, ip_addr ip, ip_addr amask) /* Update accept mask part M2 and go deeper */ n->accept = ipa_or(n->accept, ipa_and(amask, n->mask)); - /* n->plen < plen and plen <= 32 */ + /* n->plen < plen and plen <= 32 (128) */ o = n; n = n->c[ipa_getbit(paddr, n->plen) ? 1 : 0]; } /* We add new tail node 'a' after node 'o' */ - struct f_trie_node *a = new_node(plen, paddr, pmask, amask); + struct f_trie_node *a = new_node(t, plen, paddr, pmask, amask); attach_node(o, a); } /** - * trie_add_prefix - * @t: trie to add to - * @px: prefix to add - * - * Adds prefix (prefix pattern) @px to trie @t. - */ -void -trie_add_prefix(struct f_trie *t, struct f_prefix *px) -{ - int l, h; - int plen = px->len & LEN_MASK; - - /* 'l' and 'h' are lower and upper bounds on accepted - prefix lengths, both inclusive. 0 <= l, h <= 32 */ - f_prefix_get_bounds(px, &l, &h); - - if (l == 0) - t->zero = 1; - else - l--; - - ip_addr amask = ipa_xor(ipa_mkmask(l), ipa_mkmask(h)); - /* MIN(plen, h) instead of just plen is a little trick. */ - add_node_to_trie(t, MIN(plen, h), px->ip, amask); -} - -/** - * trie_match_prefix + * trie_match * @t: trie - * @px: prefix + * @px: prefix address + * @plen: prefix length * * Tries to find a matching prefix pattern in the trie such that - * prefix @px matches that prefix pattern. Returns 1 if there + * prefix @px/@plen matches that prefix pattern. Returns 1 if there * is such prefix pattern in the trie. */ int -trie_match_prefix(struct f_trie *t, struct f_prefix *px) +trie_match_prefix(struct f_trie *t, ip_addr px, int plen) { - int plen = px->len & LEN_MASK; ip_addr pmask = ipa_mkmask(plen); - ip_addr paddr = ipa_and(px->ip, pmask); + ip_addr paddr = ipa_and(px, pmask); if (plen == 0) return t->zero; -- cgit v1.2.3