diff --git a/extend.c b/extend.c
index e255d6f..8144213 100644
--- a/extend.c
+++ b/extend.c
@@ -77,7 +77,7 @@ static int cache_get(const struct sockaddr_ina *dst)
     uint8_t key[KEY_SIZE] = { 0 };
     int len = serialize_addr(dst, key, sizeof(key));
     
-    struct elem *val = mem_get(params.mempool, (char *)key, len);
+    struct elem_i *val = (struct elem_i *)mem_get(params.mempool, (char *)key, len);
     if (!val) {
         return -1;
     }
@@ -106,7 +106,7 @@ static int cache_add(const struct sockaddr_ina *dst, int m)
     LOG(LOG_S, "save ip: %s, m=%d\n", ADDR_STR, m);
     time_t t = time(0);
 
-    struct elem *val = mem_add(params.mempool, (char *)key, len);
+    struct elem_i *val = (struct elem_i *)mem_add(params.mempool, (char *)key, len, sizeof(struct elem_i));
     if (!val) {
         uniperror("mem_add");
         return -1;
diff --git a/main.c b/main.c
index b539132..8ce122b 100644
--- a/main.c
+++ b/main.c
@@ -306,7 +306,7 @@ struct mphdr *parse_hosts(char *buffer, size_t size)
             s++;
             continue;
         }
-        if (mem_add(hdr, s, e - s) == 0) {
+        if (mem_add(hdr, s, e - s, sizeof(struct elem)) == 0) {
             free(hdr);
             return 0;
         }
diff --git a/mpool.c b/mpool.c
index 50fe43e..8ac1fb2 100644
--- a/mpool.c
+++ b/mpool.c
@@ -15,68 +15,70 @@ static inline int scmp(const struct elem *p, const struct elem *q)
 KAVL_INIT(my, struct elem, head, scmp)
 
 
-struct mphdr *mem_pool(bool cst)
+struct mphdr *mem_pool(bool is_static)
 {
     struct mphdr *hdr = calloc(sizeof(struct mphdr), 1);
     if (hdr) {
-        hdr->stat = cst;
+        hdr->static_data = is_static;
     }
     return hdr;
 }
 
 
-struct elem *mem_get(struct mphdr *hdr, char *str, int len)
+struct elem *mem_get(const struct mphdr *hdr, const char *str, int len)
 {
     struct {
         int len;
-        char *data;
+        const char *data;
     } temp = { .len = len, .data = str };
     
     return kavl_find(my, hdr->root, (struct elem *)&temp, 0);
 }
 
 
-struct elem *mem_add(struct mphdr *hdr, char *str, int len)
+struct elem *mem_add(struct mphdr *hdr, char *str, int len, size_t struct_size)
 {
-    struct elem *v, *e = calloc(sizeof(struct elem), 1);
+    struct elem *v, *e = calloc(struct_size, 1);
     if (!e) {
         return 0;
     }
     e->len = len;
-    if (!hdr->stat) {
-        e->data = malloc(len);
-        if (!e->data) {
-            free(e);
-            return 0;
+    while (1) {
+        if (!hdr->static_data) {
+            e->data = malloc(len);
+            if (!e->data) {
+                break;
+            }
+            memcpy(e->data, str, len);
         }
-        memcpy(e->data, str, len);
-    }
-    else {
-        e->data = str;
-    }
-    v = kavl_insert(my, &hdr->root, e, 0);
-    if (e != v) {
-        if (!hdr->stat) {
-            free(e->data);
+        else {
+            e->data = str;
         }
-        free(e);
+        v = kavl_insert(my, &hdr->root, e, 0);
+        if (e != v) {
+            if (!hdr->static_data)
+                free(e->data);
+            break;
+        }
+        return v;
     }
-    return v;
+    free(e);
+    return 0;
 }
 
 
-void mem_delete(struct mphdr *hdr, char *str, int len)
+void mem_delete(struct mphdr *hdr, const char *str, int len)
 {
     struct {
         int len;
-        char *data;
+        const char *data;
     } temp = { .len = len, .data = str };
     
     struct elem *e = kavl_erase(my, &hdr->root, (struct elem *)&temp, 0);
     if (!e) {
         return;
     }
-    if (!hdr->stat) {
+    if (!hdr->static_data) {
         free(e->data);
         e->data = 0;
     }
@@ -91,7 +93,7 @@ void mem_destroy(struct mphdr *hdr)
         if (!e) {
             break;
         }
-        if (!hdr->stat && e->data) {
+        if (!hdr->static_data) {
             free(e->data);
         }
         e->data = 0;
diff --git a/mpool.h b/mpool.h
index c209dc0..cf60d85 100644
--- a/mpool.h
+++ b/mpool.h
@@ -8,23 +8,27 @@
 struct elem {
     int len;
     char *data;
-    int m;
-    time_t time;
     KAVL_HEAD(struct elem) head;
 };
 
+struct elem_i {
+    struct elem i;
+    int m;
+    time_t time;
+};
+
 struct mphdr {
-    bool stat;
+    bool static_data;
     struct elem *root;
 };
 
-struct mphdr *mem_pool(bool cst);
+struct mphdr *mem_pool(bool is_static);
 
-struct elem *mem_get(struct mphdr *hdr, char *str, int len);
+struct elem *mem_get(const struct mphdr *hdr, const char *str, int len);
 
-struct elem *mem_add(struct mphdr *hdr, char *str, int len);
+struct elem *mem_add(struct mphdr *hdr, char *str, int len, size_t ssize);
 
-void mem_delete(struct mphdr *hdr, char *str, int len);
+void mem_delete(struct mphdr *hdr, const char *str, int len);
 
 void mem_destroy(struct mphdr *hdr);