Mercurial > hg > nginx
view src/core/ngx_rbtree.c @ 6847:d72b38376092
Resolver: fixed handling of partially resolved SRV.
The resolver handles SRV requests in two stages. In the first
stage it gets all SRV RRs, and in the second stage it resolves
the names from SRV RRs into addresses.
Previously, if a response to an SRV request was cached, the
queries to resolve names were not limited by a timeout. If a
response to any of these queries was not received, the SRV
request could never complete.
If a response to an SRV request was not cached, and some of the
queries to resolve names timed out, NGX_RESOLVE_TIMEDOUT was
returned instead of successfully resolved addresses.
To fix both issues, resolving of names is now always limited by
a timeout.
author | Dmitry Volyntsev <xeioex@nginx.com> |
---|---|
date | Fri, 16 Dec 2016 18:21:55 +0300 |
parents | 1f513d7f1b45 |
children | b3c5b4312667 |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> /* * The red-black tree code is based on the algorithm described in * the "Introduction to Algorithms" by Cormen, Leiserson and Rivest. */ static ngx_inline void ngx_rbtree_left_rotate(ngx_rbtree_node_t **root, ngx_rbtree_node_t *sentinel, ngx_rbtree_node_t *node); static ngx_inline void ngx_rbtree_right_rotate(ngx_rbtree_node_t **root, ngx_rbtree_node_t *sentinel, ngx_rbtree_node_t *node); void ngx_rbtree_insert(ngx_rbtree_t *tree, ngx_rbtree_node_t *node) { ngx_rbtree_node_t **root, *temp, *sentinel; /* a binary tree insert */ root = (ngx_rbtree_node_t **) &tree->root; sentinel = tree->sentinel; if (*root == sentinel) { node->parent = NULL; node->left = sentinel; node->right = sentinel; ngx_rbt_black(node); *root = node; return; } tree->insert(*root, node, sentinel); /* re-balance tree */ while (node != *root && ngx_rbt_is_red(node->parent)) { if (node->parent == node->parent->parent->left) { temp = node->parent->parent->right; if (ngx_rbt_is_red(temp)) { ngx_rbt_black(node->parent); ngx_rbt_black(temp); ngx_rbt_red(node->parent->parent); node = node->parent->parent; } else { if (node == node->parent->right) { node = node->parent; ngx_rbtree_left_rotate(root, sentinel, node); } ngx_rbt_black(node->parent); ngx_rbt_red(node->parent->parent); ngx_rbtree_right_rotate(root, sentinel, node->parent->parent); } } else { temp = node->parent->parent->left; if (ngx_rbt_is_red(temp)) { ngx_rbt_black(node->parent); ngx_rbt_black(temp); ngx_rbt_red(node->parent->parent); node = node->parent->parent; } else { if (node == node->parent->left) { node = node->parent; ngx_rbtree_right_rotate(root, sentinel, node); } ngx_rbt_black(node->parent); ngx_rbt_red(node->parent->parent); ngx_rbtree_left_rotate(root, sentinel, node->parent->parent); } } } ngx_rbt_black(*root); } void ngx_rbtree_insert_value(ngx_rbtree_node_t *temp, ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel) { ngx_rbtree_node_t **p; for ( ;; ) { p = (node->key < temp->key) ? &temp->left : &temp->right; if (*p == sentinel) { break; } temp = *p; } *p = node; node->parent = temp; node->left = sentinel; node->right = sentinel; ngx_rbt_red(node); } void ngx_rbtree_insert_timer_value(ngx_rbtree_node_t *temp, ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel) { ngx_rbtree_node_t **p; for ( ;; ) { /* * Timer values * 1) are spread in small range, usually several minutes, * 2) and overflow each 49 days, if milliseconds are stored in 32 bits. * The comparison takes into account that overflow. */ /* node->key < temp->key */ p = ((ngx_rbtree_key_int_t) (node->key - temp->key) < 0) ? &temp->left : &temp->right; if (*p == sentinel) { break; } temp = *p; } *p = node; node->parent = temp; node->left = sentinel; node->right = sentinel; ngx_rbt_red(node); } void ngx_rbtree_delete(ngx_rbtree_t *tree, ngx_rbtree_node_t *node) { ngx_uint_t red; ngx_rbtree_node_t **root, *sentinel, *subst, *temp, *w; /* a binary tree delete */ root = (ngx_rbtree_node_t **) &tree->root; sentinel = tree->sentinel; if (node->left == sentinel) { temp = node->right; subst = node; } else if (node->right == sentinel) { temp = node->left; subst = node; } else { subst = ngx_rbtree_min(node->right, sentinel); if (subst->left != sentinel) { temp = subst->left; } else { temp = subst->right; } } if (subst == *root) { *root = temp; ngx_rbt_black(temp); /* DEBUG stuff */ node->left = NULL; node->right = NULL; node->parent = NULL; node->key = 0; return; } red = ngx_rbt_is_red(subst); if (subst == subst->parent->left) { subst->parent->left = temp; } else { subst->parent->right = temp; } if (subst == node) { temp->parent = subst->parent; } else { if (subst->parent == node) { temp->parent = subst; } else { temp->parent = subst->parent; } subst->left = node->left; subst->right = node->right; subst->parent = node->parent; ngx_rbt_copy_color(subst, node); if (node == *root) { *root = subst; } else { if (node == node->parent->left) { node->parent->left = subst; } else { node->parent->right = subst; } } if (subst->left != sentinel) { subst->left->parent = subst; } if (subst->right != sentinel) { subst->right->parent = subst; } } /* DEBUG stuff */ node->left = NULL; node->right = NULL; node->parent = NULL; node->key = 0; if (red) { return; } /* a delete fixup */ while (temp != *root && ngx_rbt_is_black(temp)) { if (temp == temp->parent->left) { w = temp->parent->right; if (ngx_rbt_is_red(w)) { ngx_rbt_black(w); ngx_rbt_red(temp->parent); ngx_rbtree_left_rotate(root, sentinel, temp->parent); w = temp->parent->right; } if (ngx_rbt_is_black(w->left) && ngx_rbt_is_black(w->right)) { ngx_rbt_red(w); temp = temp->parent; } else { if (ngx_rbt_is_black(w->right)) { ngx_rbt_black(w->left); ngx_rbt_red(w); ngx_rbtree_right_rotate(root, sentinel, w); w = temp->parent->right; } ngx_rbt_copy_color(w, temp->parent); ngx_rbt_black(temp->parent); ngx_rbt_black(w->right); ngx_rbtree_left_rotate(root, sentinel, temp->parent); temp = *root; } } else { w = temp->parent->left; if (ngx_rbt_is_red(w)) { ngx_rbt_black(w); ngx_rbt_red(temp->parent); ngx_rbtree_right_rotate(root, sentinel, temp->parent); w = temp->parent->left; } if (ngx_rbt_is_black(w->left) && ngx_rbt_is_black(w->right)) { ngx_rbt_red(w); temp = temp->parent; } else { if (ngx_rbt_is_black(w->left)) { ngx_rbt_black(w->right); ngx_rbt_red(w); ngx_rbtree_left_rotate(root, sentinel, w); w = temp->parent->left; } ngx_rbt_copy_color(w, temp->parent); ngx_rbt_black(temp->parent); ngx_rbt_black(w->left); ngx_rbtree_right_rotate(root, sentinel, temp->parent); temp = *root; } } } ngx_rbt_black(temp); } static ngx_inline void ngx_rbtree_left_rotate(ngx_rbtree_node_t **root, ngx_rbtree_node_t *sentinel, ngx_rbtree_node_t *node) { ngx_rbtree_node_t *temp; temp = node->right; node->right = temp->left; if (temp->left != sentinel) { temp->left->parent = node; } temp->parent = node->parent; if (node == *root) { *root = temp; } else if (node == node->parent->left) { node->parent->left = temp; } else { node->parent->right = temp; } temp->left = node; node->parent = temp; } static ngx_inline void ngx_rbtree_right_rotate(ngx_rbtree_node_t **root, ngx_rbtree_node_t *sentinel, ngx_rbtree_node_t *node) { ngx_rbtree_node_t *temp; temp = node->left; node->left = temp->right; if (temp->right != sentinel) { temp->right->parent = node; } temp->parent = node->parent; if (node == *root) { *root = temp; } else if (node == node->parent->right) { node->parent->right = temp; } else { node->parent->left = temp; } temp->right = node; node->parent = temp; }