diff --git a/src/api/api_msg.c b/src/api/api_msg.c
index 1a112789..8c9c24b0 100644
--- a/src/api/api_msg.c
+++ b/src/api/api_msg.c
@@ -71,7 +71,7 @@ recv_raw(void *arg, struct raw_pcb *pcb, struct pbuf *p,
 
   if ((conn != NULL) && (conn->recvmbox != SYS_MBOX_NULL)) {
     buf = memp_malloc(MEMP_NETBUF);
-    if (!buf) {
+    if (buf == NULL) {
       return 0;
     }
     pbuf_ref(p);
diff --git a/src/api/tcpip.c b/src/api/tcpip.c
index 87a31fad..b71fb96d 100644
--- a/src/api/tcpip.c
+++ b/src/api/tcpip.c
@@ -245,14 +245,14 @@ ethernet_input(struct pbuf *p, struct netif *netif)
       etharp_arp_input(netif, (struct eth_addr*)(netif->hwaddr), p);
       break;
 
-#if PPPOE_SUPPORT > 0
-	case ETHTYPE_PPPOEDISC: /* PPP Over Ethernet Discovery Stage */
-	  pppoe_disc_input(netif, p);
-	  break;
-	case ETHTYPE_PPPOE: /* PPP Over Ethernet Session Stage */
-	  pppoe_data_input(netif, p);
-	  break;
-#endif
+#if PPPOE_SUPPORT
+    case ETHTYPE_PPPOEDISC: /* PPP Over Ethernet Discovery Stage */
+      pppoe_disc_input(netif, p);
+      break;
+    case ETHTYPE_PPPOE: /* PPP Over Ethernet Session Stage */
+      pppoe_data_input(netif, p);
+      break;
+#endif /* PPPOE_SUPPORT */
 
     default:
       pbuf_free(p);
diff --git a/src/core/mem.c b/src/core/mem.c
index b0885267..407d1a87 100644
--- a/src/core/mem.c
+++ b/src/core/mem.c
@@ -503,12 +503,12 @@ mem_malloc(mem_size_t size)
 
 void *mem_calloc(size_t count, size_t size)
 {
-    void *p;
+  void *p;
 
-    p = mem_malloc(count * size);
-    if(p) {
-        memset(p, 0, count * size);
-    }
-    return p;
+  p = mem_malloc(count * size);
+  if(p) {
+    memset(p, 0, count * size);
+  }
+  return p;
 }
 #endif /* !MEM_LIBC_MALLOC */
diff --git a/src/core/tcp_in.c b/src/core/tcp_in.c
index 9aae63ba..38383509 100644
--- a/src/core/tcp_in.c
+++ b/src/core/tcp_in.c
@@ -301,8 +301,9 @@ tcp_input(struct pbuf *p, struct netif *inp)
         }
       
         if (recv_data != NULL) {
-          if(flags & TCP_PSH)
-			recv_data->flgs |= PBUF_FLAG_PUSH;
+          if(flags & TCP_PSH) {
+            recv_data->flgs |= PBUF_FLAG_PUSH;
+          }
           /* Notify application that data has been received. */
           TCP_EVENT_RECV(pcb, recv_data, ERR_OK, err);
         }
diff --git a/src/include/lwip/mem.h b/src/include/lwip/mem.h
index f80e3b97..36c8781b 100644
--- a/src/include/lwip/mem.h
+++ b/src/include/lwip/mem.h
@@ -83,8 +83,8 @@ void  mem_init(void);
 void *mem_realloc(void *mem, mem_size_t size);
 #endif /* MEM_USE_POOLS */
 void *mem_malloc(mem_size_t size);
-void  mem_free(void *mem);
 void *mem_calloc(size_t count, size_t size);
+void  mem_free(void *mem);
 #endif /* MEM_LIBC_MALLOC */
 
 #ifndef LWIP_MEM_ALIGN_SIZE
diff --git a/src/include/netif/etharp.h b/src/include/netif/etharp.h
index 52a3e8b9..6b763c4c 100644
--- a/src/include/netif/etharp.h
+++ b/src/include/netif/etharp.h
@@ -119,8 +119,8 @@ PACK_STRUCT_END
 /** 5 seconds period */
 #define ARP_TMR_INTERVAL 5000
 
-#define ETHTYPE_ARP 0x0806
-#define ETHTYPE_IP  0x0800
+#define ETHTYPE_ARP       0x0806
+#define ETHTYPE_IP        0x0800
 #define ETHTYPE_PPPOEDISC 0x8863  /* PPP Over Ethernet Discovery Stage */
 #define ETHTYPE_PPPOE     0x8864  /* PPP Over Ethernet Session Stage */
 
diff --git a/src/netif/ethernetif.c b/src/netif/ethernetif.c
index db45767e..d6cdbd22 100644
--- a/src/netif/ethernetif.c
+++ b/src/netif/ethernetif.c
@@ -288,14 +288,14 @@ ethernetif_input(struct netif *netif)
 #endif /* ETHARP_TCPIP_INPUT */
 #endif /* ETHARP_TCPIP_ETHINPUT */
 
-#if PPPOE_SUPPORT > 0
+#if PPPOE_SUPPORT
   case ETHTYPE_PPPOEDISC: /* PPP Over Ethernet Discovery Stage */
-	pppoe_disc_input(netif, p);
-	break;
+    pppoe_disc_input(netif, p);
+    break;
   case ETHTYPE_PPPOE: /* PPP Over Ethernet Session Stage */
-	pppoe_data_input(netif, p);
-	break;
-#endif
+    pppoe_data_input(netif, p);
+    break;
+#endif /* PPPOE_SUPPORT */
 
   default:
     pbuf_free(p);