Let netdb use a memp pool for allocating memory when getaddrinfo() is called.

CHANGELOG

@@ -19,6 +19,10 @@ HISTORY
 
   ++ New features:
 
+  2010-02-01: Simon Goldschmidt
+  * opt.h, memp_std.h, dns.h, netdb.c, memp.c: Let netdb use a memp pool
+    for allocating memory when getaddrinfo() is called.
+
   2010-01-31: Simon Goldschmidt
   * dhcp.h, dhcp.c: Reworked the code that parses DHCP options: parse
     them once instead of parsing for every option. This also removes

src/api/netdb.c

@@ -39,8 +39,10 @@
 
 #include "lwip/err.h"
 #include "lwip/mem.h"
+#include "lwip/memp.h"
 #include "lwip/ip_addr.h"
 #include "lwip/api.h"
+#include "lwip/dns.h"
 
 #include <string.h>
 #include <stdlib.h>
@@ -235,7 +237,7 @@ lwip_freeaddrinfo(struct addrinfo *ai)
 
   while (ai != NULL) {
     next = ai->ai_next;
-    mem_free(ai);
+    memp_free(MEMP_NETDB, ai);
     ai = next;
   }
 }
@@ -305,7 +307,10 @@ lwip_getaddrinfo(const char *nodename, const char *servname,
     LWIP_ASSERT("namelen is too long", (namelen + 1) <= (mem_size_t)-1);
     total_size += namelen + 1;
   }
-  ai = mem_malloc(total_size);
+  /* If this fails, please report to lwip-devel! :-) */
+  LWIP_ASSERT("total_size <= NETDB_ELEM_SIZE: please report this!",
+    total_size <= NETDB_ELEM_SIZE);
+  ai = memp_malloc(MEMP_NETDB);
   if (ai == NULL) {
     goto memerr;
   }
@@ -338,7 +343,7 @@ lwip_getaddrinfo(const char *nodename, const char *servname,
   return 0;
 memerr:
   if (ai != NULL) {
-    mem_free(ai);
+    memp_free(MEMP_NETDB, ai);
   }
   return EAI_MEMORY;
 }

src/core/memp.c

@@ -56,6 +56,7 @@
 #include "lwip/ip_frag.h"
 #include "lwip/snmp_structs.h"
 #include "lwip/snmp_msg.h"
+#include "lwip/dns.h"
 
 #include <string.h>
 

src/include/lwip/dns.h

@@ -66,6 +66,13 @@
 #define DNS_RRCLASS_HS            4     /* Hesiod [Dyer 87] */
 #define DNS_RRCLASS_FLUSH         0x800 /* Flush bit */
 
+/* The size used for the next line is rather a hack, but it prevents including socket.h in all files
+   that include memp.h, and that would possibly break portability (since socket.h defines some types
+   and constants possibly already define by the OS).
+   Calculation rule:
+   sizeof(struct addrinfo) + sizeof(struct sockaddr_in) + DNS_MAX_NAME_LENGTH + 1 byte zero-termination */
+#define NETDB_ELEM_SIZE           (32 + 16 + DNS_MAX_NAME_LENGTH + 1)
+
 /** Callback which is invoked when a hostname is found.
  * A function of this type must be implemented by the application using the DNS resolver.
  * @param name pointer to the name that was looked up.
@@ -75,15 +82,10 @@
 */
 typedef void (*dns_found_callback)(const char *name, struct ip_addr *ipaddr, void *callback_arg);
 
-
 void           dns_init(void);
-
 void           dns_tmr(void);
-
 void           dns_setserver(u8_t numdns, struct ip_addr *dnsserver);
-
 struct ip_addr dns_getserver(u8_t numdns);
-
 err_t          dns_gethostbyname(const char *hostname, struct ip_addr *addr,
                                  dns_found_callback found, void *callback_arg);
 

src/include/lwip/memp_std.h

@@ -74,6 +74,9 @@ LWIP_MEMPOOL(SNMP_NODE,      MEMP_NUM_SNMP_NODE,       sizeof(struct mib_list_no
 LWIP_MEMPOOL(SNMP_VARBIND,   MEMP_NUM_SNMP_VARBIND,    sizeof(struct snmp_varbind),      "SNMP_VARBIND")
 LWIP_MEMPOOL(SNMP_VALUE,     MEMP_NUM_SNMP_VALUE,      SNMP_MAX_VALUE_SIZE,              "SNMP_VALUE")
 #endif /* LWIP_SNMP */
+#if LWIP_DNS && LWIP_SOCKET
+LWIP_MEMPOOL(NETDB,          MEMP_NUM_NETDB,           NETDB_ELEM_SIZE,               "NETDB")
+#endif /* LWIP_DNS && LWIP_SOCKET */
 
 /*
  * A list of pools of pbuf's used by LWIP.

src/include/lwip/opt.h

@@ -362,6 +362,14 @@
 #define MEMP_NUM_SNMP_VALUE             3
 #endif
 
+/**
+ * MEMP_NUM_NETDB: the number of concurrently running lwip_addrinfo() calls
+ * (before freeing the corresponding memory using lwip_freeaddrinfo()).
+ */
+#ifndef MEMP_NUM_NETDB
+#define MEMP_NUM_NETDB                  1
+#endif
+
 /**
  * PBUF_POOL_SIZE: the number of buffers in the pbuf pool. 
  */