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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187/* Copyright (c) 2003 Juan Lang * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA * * This implementation uses a linked list, because I don't have a decent * hash table implementation handy. This is somewhat inefficient, but it's * rather more efficient than not having a name cache at all. */
#include "netapi32.h"
typedef struct _NBNameCacheNode{ DWORD expireTime; NBNameCacheEntry *entry; struct _NBNameCacheNode *next;} NBNameCacheNode;
struct NBNameCache{ HANDLE heap; CRITICAL_SECTION cs; DWORD entryExpireTimeMS; NBNameCacheNode *head;};
/* Unlinks the node pointed to by *prev, and frees any associated memory. * If that node's next pointed to another node, *prev now points to it. * Assumes the caller owns cache's lock. */static void NBNameCacheUnlinkNode(struct NBNameCache *cache, NBNameCacheNode **prev){ if (cache && prev && *prev) { NBNameCacheNode *next = (*prev)->next;
HeapFree(cache->heap, 0, (*prev)->entry); HeapFree(cache->heap, 0, *prev); *prev = next; }}
/* Walks the list beginning with cache->head looking for the node with name * name. If the node is found, returns a pointer to the next pointer of the * node _prior_ to the found node (or head if head points to it). Thus, if the * node's all you want, dereference the return value twice. If you want to * modify the list, modify the referent of the return value. * While it's at it, deletes nodes whose time has expired (except the node * you're looking for, of course). * Returns NULL if the node isn't found. * Assumes the caller owns cache's lock. */static NBNameCacheNode **NBNameCacheWalk(struct NBNameCache *cache, const char name[NCBNAMSZ]){ NBNameCacheNode **ret = NULL;
if (cache && cache->head) { NBNameCacheNode **ptr;
ptr = &cache->head; while (ptr && *ptr && (*ptr)->entry) { if (!memcmp((*ptr)->entry->name, name, NCBNAMSZ - 1)) ret = ptr; else { if (GetTickCount() > (*ptr)->expireTime) NBNameCacheUnlinkNode(cache, ptr); } if (*ptr) ptr = &(*ptr)->next; } } return ret;}
struct NBNameCache *NBNameCacheCreate(HANDLE heap, DWORD entryExpireTimeMS){ struct NBNameCache *cache; if (!heap) heap = GetProcessHeap(); cache = HeapAlloc(heap, 0, sizeof(struct NBNameCache)); if (cache) { cache->heap = heap; InitializeCriticalSection(&cache->cs); cache->cs.DebugInfo->Spare[0] = (DWORD_PTR)(__FILE__ ": NBNameCache.cs"); cache->entryExpireTimeMS = entryExpireTimeMS; cache->head = NULL; } return cache;}
BOOL NBNameCacheAddEntry(struct NBNameCache *cache, NBNameCacheEntry *entry){ BOOL ret;
if (cache && entry) { NBNameCacheNode **node;
EnterCriticalSection(&cache->cs); node = NBNameCacheWalk(cache, (char*)entry->name); if (node) { (*node)->expireTime = GetTickCount() + cache->entryExpireTimeMS; HeapFree(cache->heap, 0, (*node)->entry); (*node)->entry = entry; ret = TRUE; } else { NBNameCacheNode *newNode = HeapAlloc(cache->heap, 0, sizeof(NBNameCacheNode)); if (newNode) { newNode->expireTime = GetTickCount() + cache->entryExpireTimeMS; newNode->entry = entry; newNode->next = cache->head; cache->head = newNode; ret = TRUE; } else ret = FALSE; } LeaveCriticalSection(&cache->cs); } else ret = FALSE; return ret;}
const NBNameCacheEntry *NBNameCacheFindEntry(struct NBNameCache *cache, const UCHAR name[NCBNAMSZ]){ const NBNameCacheEntry *ret; UCHAR printName[NCBNAMSZ];
memcpy(printName, name, NCBNAMSZ - 1); printName[NCBNAMSZ - 1] = '\0'; if (cache) { NBNameCacheNode **node;
EnterCriticalSection(&cache->cs); node = NBNameCacheWalk(cache, (const char *)name); if (node) ret = (*node)->entry; else ret = NULL; LeaveCriticalSection(&cache->cs); } else ret = NULL; return ret;}
void NBNameCacheDestroy(struct NBNameCache *cache){ if (cache) { cache->cs.DebugInfo->Spare[0] = 0; DeleteCriticalSection(&cache->cs); while (cache->head) NBNameCacheUnlinkNode(cache, &cache->head); HeapFree(cache->heap, 0, cache); }}