DNS_LOCAL_HOSTLIST_IS_DYNAMIC uses its own MEMP pool instead of the heap

src/core/dns.c

@@ -78,6 +78,7 @@
 
 #include "lwip/udp.h"
 #include "lwip/mem.h"
+#include "lwip/memp.h"
 #include "lwip/dns.h"
 
 #include <string.h>
@@ -180,14 +181,6 @@ struct dns_table_entry {
 };
 
 #if DNS_LOCAL_HOSTLIST
-/** struct used for local host-list */
-struct local_hostlist_entry {
-  /** static hostname */
-  const char *name;
-  /** static host address in network byteorder */
-  ip_addr_t addr;
-  struct local_hostlist_entry *next;
-};
 
 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
 /** Local host-list. For hostnames in this list, no
@@ -329,7 +322,8 @@ dns_init_local()
     struct local_hostlist_entry *init_entry = &local_hostlist_init[i];
     LWIP_ASSERT("invalid host name (NULL)", init_entry->name != NULL);
     namelen = strlen(init_entry->name);
-    entry = mem_malloc((mem_size_t)(sizeof(struct local_hostlist_entry) + namelen + 1));
+    LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
+    entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
     LWIP_ASSERT("mem-error in dns_init_local", entry != NULL);
     if (entry != NULL) {
       entry->name = (char*)entry + sizeof(struct local_hostlist_entry);
@@ -398,7 +392,7 @@ dns_local_removehost(const char *hostname, const ip_addr_t *addr)
       }
       free_entry = entry;
       entry = entry->next;
-      mem_free(free_entry);
+      memp_free(MEMP_LOCALHOSTLIST, free_entry);
       removed++;
     } else {
       last_entry = entry;
@@ -423,7 +417,8 @@ dns_local_addhost(const char *hostname, const ip_addr_t *addr)
   size_t namelen;
   LWIP_ASSERT("invalid host name (NULL)", hostname != NULL);
   namelen = strlen(hostname);
-  entry = mem_malloc((mem_size_t)(sizeof(struct local_hostlist_entry) + namelen + 1));
+  LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
+  entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
   if (entry == NULL) {
     return ERR_MEM;
   }

src/include/lwip/dns.h

@@ -73,6 +73,23 @@
    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)
 
+#if DNS_LOCAL_HOSTLIST
+/** struct used for local host-list */
+struct local_hostlist_entry {
+  /** static hostname */
+  const char *name;
+  /** static host address in network byteorder */
+  ip_addr_t addr;
+  struct local_hostlist_entry *next;
+};
+#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
+#ifndef DNS_LOCAL_HOSTLIST_MAX_NAMELEN
+#define DNS_LOCAL_HOSTLIST_MAX_NAMELEN  DNS_MAX_NAME_LENGTH
+#endif
+#define LOCALHOSTLIST_ELEM_SIZE ((sizeof(struct local_hostlist_entry) + DNS_LOCAL_HOSTLIST_MAX_NAMELEN + 1))
+#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
+#endif /* DNS_LOCAL_HOSTLIST */
+
 /** 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.

src/include/lwip/memp_std.h

@@ -79,6 +79,9 @@ LWIP_MEMPOOL(SNMP_VALUE,     MEMP_NUM_SNMP_VALUE,      SNMP_MAX_VALUE_SIZE,
 #if LWIP_DNS && LWIP_SOCKET
 LWIP_MEMPOOL(NETDB,          MEMP_NUM_NETDB,           NETDB_ELEM_SIZE,               "NETDB")
 #endif /* LWIP_DNS && LWIP_SOCKET */
+#if LWIP_DNS && DNS_LOCAL_HOSTLIST && DNS_LOCAL_HOSTLIST_IS_DYNAMIC
+LWIP_MEMPOOL(LOCALHOSTLIST,  MEMP_NUM_LOCALHOSTLIST,   LOCALHOSTLIST_ELEM_SIZE,       "LOCALHOSTLIST")
+#endif /* LWIP_DNS && DNS_LOCAL_HOSTLIST && DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
 
 /*
  * A list of pools of pbuf's used by LWIP.

src/include/lwip/opt.h

@@ -370,6 +370,14 @@
 #define MEMP_NUM_NETDB                  1
 #endif
 
+/**
+ * MEMP_NUM_LOCALHOSTLIST: the number of host entries in the local host list
+ * if DNS_LOCAL_HOSTLIST_IS_DYNAMIC==1.
+ */
+#ifndef MEMP_NUM_LOCALHOSTLIST
+#define MEMP_NUM_LOCALHOSTLIST          1
+#endif
+
 /**
  * PBUF_POOL_SIZE: the number of buffers in the pbuf pool. 
  */