memp.c

00001 /**
00002  * @file
00003  * Dynamic pool memory manager
00004  *
00005  * lwIP has dedicated pools for many structures (netconn, protocol control blocks,
00006  * packet buffers, ...). All these pools are managed here.
00007  */
00008 
00009 /*
00010  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
00011  * All rights reserved. 
00012  * 
00013  * Redistribution and use in source and binary forms, with or without modification, 
00014  * are permitted provided that the following conditions are met:
00015  *
00016  * 1. Redistributions of source code must retain the above copyright notice,
00017  *    this list of conditions and the following disclaimer.
00018  * 2. Redistributions in binary form must reproduce the above copyright notice,
00019  *    this list of conditions and the following disclaimer in the documentation
00020  *    and/or other materials provided with the distribution.
00021  * 3. The name of the author may not be used to endorse or promote products
00022  *    derived from this software without specific prior written permission. 
00023  *
00024  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
00025  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
00026  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
00027  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
00028  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
00029  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
00030  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
00031  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
00032  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
00033  * OF SUCH DAMAGE.
00034  *
00035  * This file is part of the lwIP TCP/IP stack.
00036  * 
00037  * Author: Adam Dunkels <adam@sics.se>
00038  *
00039  */
00040 
00041 #include "lwip/opt.h"
00042 
00043 #include "lwip/memp.h"
00044 #include "lwip/pbuf.h"
00045 #include "lwip/udp.h"
00046 #include "lwip/raw.h"
00047 #include "lwip/tcp.h"
00048 #include "lwip/igmp.h"
00049 #include "lwip/api.h"
00050 #include "lwip/api_msg.h"
00051 #include "lwip/tcpip.h"
00052 #include "lwip/sys.h"
00053 #include "lwip/stats.h"
00054 #include "netif/etharp.h"
00055 #include "lwip/ip_frag.h"
00056 
00057 #include <string.h>
00058 
00059 struct memp {
00060   struct memp *next;
00061 #if MEMP_OVERFLOW_CHECK
00062   const char *file;
00063   int line;
00064 #endif /* MEMP_OVERFLOW_CHECK */
00065 };
00066 
00067 #if MEMP_OVERFLOW_CHECK
00068 /* if MEMP_OVERFLOW_CHECK is turned on, we reserve some bytes at the beginning
00069  * and at the end of each element, initialize them as 0xcd and check
00070  * them later. */
00071 /* If MEMP_OVERFLOW_CHECK is >= 2, on every call to memp_malloc or memp_free,
00072  * every single element in each pool is checked!
00073  * This is VERY SLOW but also very helpful. */
00074 /* MEMP_SANITY_REGION_BEFORE and MEMP_SANITY_REGION_AFTER can be overridden in
00075  * lwipopts.h to change the amount reserved for checking. */
00076 #ifndef MEMP_SANITY_REGION_BEFORE
00077 #define MEMP_SANITY_REGION_BEFORE  16
00078 #endif /* MEMP_SANITY_REGION_BEFORE*/
00079 #if MEMP_SANITY_REGION_BEFORE > 0
00080 #define MEMP_SANITY_REGION_BEFORE_ALIGNED    LWIP_MEM_ALIGN_SIZE(MEMP_SANITY_REGION_BEFORE)
00081 #else
00082 #define MEMP_SANITY_REGION_BEFORE_ALIGNED    0
00083 #endif /* MEMP_SANITY_REGION_BEFORE*/
00084 #ifndef MEMP_SANITY_REGION_AFTER
00085 #define MEMP_SANITY_REGION_AFTER   16
00086 #endif /* MEMP_SANITY_REGION_AFTER*/
00087 #if MEMP_SANITY_REGION_AFTER > 0
00088 #define MEMP_SANITY_REGION_AFTER_ALIGNED     LWIP_MEM_ALIGN_SIZE(MEMP_SANITY_REGION_AFTER)
00089 #else
00090 #define MEMP_SANITY_REGION_AFTER_ALIGNED     0
00091 #endif /* MEMP_SANITY_REGION_AFTER*/
00092 
00093 /* MEMP_SIZE: save space for struct memp and for sanity check */
00094 #define MEMP_SIZE          (LWIP_MEM_ALIGN_SIZE(sizeof(struct memp)) + MEMP_SANITY_REGION_BEFORE_ALIGNED)
00095 #define MEMP_ALIGN_SIZE(x) (LWIP_MEM_ALIGN_SIZE(x) + MEMP_SANITY_REGION_AFTER_ALIGNED)
00096 
00097 #else /* MEMP_OVERFLOW_CHECK */
00098 
00099 /* No sanity checks
00100  * We don't need to preserve the struct memp while not allocated, so we
00101  * can save a little space and set MEMP_SIZE to 0.
00102  */
00103 #define MEMP_SIZE           0
00104 #define MEMP_ALIGN_SIZE(x) (LWIP_MEM_ALIGN_SIZE(x))
00105 
00106 #endif /* MEMP_OVERFLOW_CHECK */
00107 
00108 /** This array holds the first free element of each pool.
00109  *  Elements form a linked list. */
00110 static struct memp *memp_tab[MEMP_MAX];
00111 
00112 /** This array holds the element sizes of each pool. */
00113 #if !MEM_USE_POOLS
00114 static
00115 #endif
00116 const u16_t memp_sizes[MEMP_MAX] = {
00117 #define LWIP_MEMPOOL(name,num,size,desc)  MEMP_ALIGN_SIZE(size),
00118 #include "lwip/memp_std.h"
00119 };
00120 
00121 /** This array holds the number of elements in each pool. */
00122 static const u16_t memp_num[MEMP_MAX] = {
00123 #define LWIP_MEMPOOL(name,num,size,desc)  (num),
00124 #include "lwip/memp_std.h"
00125 };
00126 
00127 /** This array holds a textual description of each pool. */
00128 #ifdef LWIP_DEBUG
00129 static const char *memp_desc[MEMP_MAX] = {
00130 #define LWIP_MEMPOOL(name,num,size,desc)  (desc),
00131 #include "lwip/memp_std.h"
00132 };
00133 #endif /* LWIP_DEBUG */
00134 
00135 /** This is the actual memory used by the pools. */
00136 static u8_t memp_memory[MEM_ALIGNMENT - 1 
00137 #define LWIP_MEMPOOL(name,num,size,desc) + ( (num) * (MEMP_SIZE + MEMP_ALIGN_SIZE(size) ) )
00138 #include "lwip/memp_std.h"
00139 ];
00140 
00141 #if MEMP_SANITY_CHECK
00142 /**
00143  * Check that memp-lists don't form a circle
00144  */
00145 static int
00146 memp_sanity(void)
00147 {
00148   s16_t i, c;
00149   struct memp *m, *n;
00150 
00151   for (i = 0; i < MEMP_MAX; i++) {
00152     for (m = memp_tab[i]; m != NULL; m = m->next) {
00153       c = 1;
00154       for (n = memp_tab[i]; n != NULL; n = n->next) {
00155         if (n == m && --c < 0) {
00156           return 0;
00157         }
00158       }
00159     }
00160   }
00161   return 1;
00162 }
00163 #endif /* MEMP_SANITY_CHECK*/
00164 #if MEMP_OVERFLOW_CHECK
00165 /**
00166  * Check if a memp element was victim of an overflow
00167  * (e.g. the restricted area after it has been altered)
00168  *
00169  * @param p the memp element to check
00170  * @param memp_size the element size of the pool p comes from
00171  */
00172 static void
00173 memp_overflow_check_element(struct memp *p, u16_t memp_size)
00174 {
00175   u16_t k;
00176   u8_t *m;
00177 #if MEMP_SANITY_REGION_BEFORE_ALIGNED > 0
00178   m = (u8_t*)p + MEMP_SIZE - MEMP_SANITY_REGION_BEFORE_ALIGNED;
00179   for (k = 0; k < MEMP_SANITY_REGION_BEFORE_ALIGNED; k++) {
00180     if (m[k] != 0xcd) {
00181       LWIP_ASSERT("detected memp underflow!", 0);
00182     }
00183   }
00184 #endif
00185 #if MEMP_SANITY_REGION_AFTER_ALIGNED > 0
00186   m = (u8_t*)p + MEMP_SIZE + memp_size - MEMP_SANITY_REGION_AFTER_ALIGNED;
00187   for (k = 0; k < MEMP_SANITY_REGION_AFTER_ALIGNED; k++) {
00188     if (m[k] != 0xcd) {
00189       LWIP_ASSERT("detected memp overflow!", 0);
00190     }
00191   }
00192 #endif
00193 }
00194 
00195 /**
00196  * Do an overflow check for all elements in every pool.
00197  *
00198  * @see memp_overflow_check_element for a description of the check
00199  */
00200 static void
00201 memp_overflow_check_all(void)
00202 {
00203   u16_t i, j;
00204   struct memp *p;
00205 
00206   p = LWIP_MEM_ALIGN(memp_memory);
00207   for (i = 0; i < MEMP_MAX; ++i) {
00208     p = p;
00209     for (j = 0; j < memp_num[i]; ++j) {
00210       memp_overflow_check_element(p, memp_sizes[i]);
00211       p = (struct memp*)((u8_t*)p + MEMP_SIZE + memp_sizes[i]);
00212     }
00213   }
00214 }
00215 
00216 /**
00217  * Initialize the restricted areas of all memp elements in every pool.
00218  */
00219 static void
00220 memp_overflow_init(void)
00221 {
00222   u16_t i, j;
00223   struct memp *p;
00224   u8_t *m;
00225 
00226   p = LWIP_MEM_ALIGN(memp_memory);
00227   for (i = 0; i < MEMP_MAX; ++i) {
00228     p = p;
00229     for (j = 0; j < memp_num[i]; ++j) {
00230 #if MEMP_SANITY_REGION_BEFORE_ALIGNED > 0
00231       m = (u8_t*)p + MEMP_SIZE - MEMP_SANITY_REGION_BEFORE_ALIGNED;
00232       memset(m, 0xcd, MEMP_SANITY_REGION_BEFORE_ALIGNED);
00233 #endif
00234 #if MEMP_SANITY_REGION_AFTER_ALIGNED > 0
00235       m = (u8_t*)p + MEMP_SIZE + memp_sizes[i] - MEMP_SANITY_REGION_AFTER_ALIGNED;
00236       memset(m, 0xcd, MEMP_SANITY_REGION_AFTER_ALIGNED);
00237 #endif
00238       p = (struct memp*)((u8_t*)p + MEMP_SIZE + memp_sizes[i]);
00239     }
00240   }
00241 }
00242 #endif /* MEMP_OVERFLOW_CHECK */
00243 
00244 /**
00245  * Initialize this module.
00246  * 
00247  * Carves out memp_memory into linked lists for each pool-type.
00248  */
00249 void
00250 memp_init(void)
00251 {
00252   struct memp *memp;
00253   u16_t i, j;
00254 
00255 #if MEMP_STATS
00256   for (i = 0; i < MEMP_MAX; ++i) {
00257     lwip_stats.memp[i].used = lwip_stats.memp[i].max =
00258       lwip_stats.memp[i].err = 0;
00259     lwip_stats.memp[i].avail = memp_num[i];
00260   }
00261 #endif /* MEMP_STATS */
00262 
00263   memp = (struct memp *)LWIP_MEM_ALIGN(memp_memory);
00264   /* for every pool: */
00265   for (i = 0; i < MEMP_MAX; ++i) {
00266     memp_tab[i] = NULL;
00267     /* create a linked list of memp elements */
00268     for (j = 0; j < memp_num[i]; ++j) {
00269       memp->next = memp_tab[i];
00270       memp_tab[i] = memp;
00271       memp = (struct memp *)((u8_t *)memp + MEMP_SIZE + memp_sizes[i]);
00272     }
00273   }
00274 #if MEMP_OVERFLOW_CHECK
00275   memp_overflow_init();
00276   /* check everything a first time to see if it worked */
00277   memp_overflow_check_all();
00278 #endif /* MEMP_OVERFLOW_CHECK */
00279 }
00280 
00281 /**
00282  * Get an element from a specific pool.
00283  *
00284  * @param type the pool to get an element from
00285  *
00286  * the debug version has two more parameters:
00287  * @param file file name calling this function
00288  * @param line number of line where this function is called
00289  *
00290  * @return a pointer to the allocated memory or a NULL pointer on error
00291  */
00292 void *
00293 #if !MEMP_OVERFLOW_CHECK
00294 memp_malloc(memp_t type)
00295 #else
00296 memp_malloc_fn(memp_t type, const char* file, const int line)
00297 #endif
00298 {
00299   struct memp *memp;
00300   SYS_ARCH_DECL_PROTECT(old_level);
00301  
00302   LWIP_ERROR("memp_malloc: type < MEMP_MAX", (type < MEMP_MAX), return NULL;);
00303 
00304   SYS_ARCH_PROTECT(old_level);
00305 #if MEMP_OVERFLOW_CHECK >= 2
00306   memp_overflow_check_all();
00307 #endif /* MEMP_OVERFLOW_CHECK >= 2 */
00308 
00309   memp = memp_tab[type];
00310   
00311   if (memp != NULL) {    
00312     memp_tab[type] = memp->next;    
00313 #if MEMP_OVERFLOW_CHECK
00314     memp->next = NULL;
00315     memp->file = file;
00316     memp->line = line;
00317 #endif /* MEMP_OVERFLOW_CHECK */
00318 #if MEMP_STATS
00319     ++lwip_stats.memp[type].used;
00320     if (lwip_stats.memp[type].used > lwip_stats.memp[type].max) {
00321       lwip_stats.memp[type].max = lwip_stats.memp[type].used;
00322     }
00323 #endif /* MEMP_STATS */
00324     LWIP_ASSERT("memp_malloc: memp properly aligned",
00325                 ((mem_ptr_t)memp % MEM_ALIGNMENT) == 0);
00326     memp = (struct memp*)((u8_t*)memp + MEMP_SIZE);
00327   } else {
00328     LWIP_DEBUGF(MEMP_DEBUG | 2, ("memp_malloc: out of memory in pool %s\n", memp_desc[type]));
00329 #if MEMP_STATS
00330     ++lwip_stats.memp[type].err;
00331 #endif /* MEMP_STATS */
00332   }
00333 
00334   SYS_ARCH_UNPROTECT(old_level);
00335 
00336   return memp;
00337 }
00338 
00339 /**
00340  * Put an element back into its pool.
00341  *
00342  * @param type the pool where to put mem
00343  * @param mem the memp element to free
00344  */
00345 void
00346 memp_free(memp_t type, void *mem)
00347 {
00348   struct memp *memp;
00349   SYS_ARCH_DECL_PROTECT(old_level);
00350 
00351   if (mem == NULL) {
00352     return;
00353   }
00354   LWIP_ASSERT("memp_free: mem properly aligned",
00355                 ((mem_ptr_t)mem % MEM_ALIGNMENT) == 0);
00356 
00357   memp = (struct memp *)((u8_t*)mem - MEMP_SIZE);
00358 
00359   SYS_ARCH_PROTECT(old_level);
00360 #if MEMP_OVERFLOW_CHECK
00361 #if MEMP_OVERFLOW_CHECK >= 2
00362   memp_overflow_check_all();
00363 #else
00364   memp_overflow_check_element(memp, memp_sizes[type]);
00365 #endif /* MEMP_OVERFLOW_CHECK >= 2 */
00366 #endif /* MEMP_OVERFLOW_CHECK */
00367 
00368 #if MEMP_STATS
00369   lwip_stats.memp[type].used--; 
00370 #endif /* MEMP_STATS */
00371   
00372   memp->next = memp_tab[type]; 
00373   memp_tab[type] = memp;
00374 
00375 #if MEMP_SANITY_CHECK
00376   LWIP_ASSERT("memp sanity", memp_sanity());
00377 #endif /* MEMP_SANITY_CHECK */
00378 
00379   SYS_ARCH_UNPROTECT(old_level);
00380 }