diff --git a/src/core/dns.c b/src/core/dns.c
index 6ad0b4b7..cc8dc852 100644
--- a/src/core/dns.c
+++ b/src/core/dns.c
@@ -183,6 +183,14 @@ struct dns_answer {
 /* maximum allowed size for the struct due to non-packed */
 #define SIZEOF_DNS_ANSWER_ASSERT 12
 
+/* DNS table entry states */
+typedef enum {
+  DNS_STATE_UNUSED           = 0,
+  DNS_STATE_NEW              = 1,
+  DNS_STATE_ASKING           = 2,
+  DNS_STATE_DONE             = 3
+} dns_state_enum_t;
+
 /** DNS table entry */
 struct dns_table_entry {
   u32_t ttl;
diff --git a/src/include/lwip/dhcp.h b/src/include/lwip/dhcp.h
index f9bdb1ee..220342b3 100644
--- a/src/include/lwip/dhcp.h
+++ b/src/include/lwip/dhcp.h
@@ -58,6 +58,12 @@ extern "C" {
 
 #define DHCP_BOOT_FILE_LEN      128U
 
+/* AutoIP cooperation flags (struct dhcp.autoip_coop_state) */
+typedef enum {
+  DHCP_AUTOIP_COOP_STATE_OFF  = 0,
+  DHCP_AUTOIP_COOP_STATE_ON   = 1
+} dhcp_autoip_coop_state_enum_t;
+
 struct dhcp
 {
   /** transaction identifier of last sent request */
diff --git a/src/include/lwip/prot/dhcp.h b/src/include/lwip/prot/dhcp.h
index c33aa04c..112953cb 100644
--- a/src/include/lwip/prot/dhcp.h
+++ b/src/include/lwip/prot/dhcp.h
@@ -114,12 +114,6 @@ typedef enum {
   DHCP_STATE_BACKING_OFF     = 12
 } dhcp_state_enum_t;
 
-/* AutoIP cooperation flags */
-typedef enum {
-  DHCP_AUTOIP_COOP_STATE_OFF  = 0,
-  DHCP_AUTOIP_COOP_STATE_ON   = 1
-} dhcp_autoip_coop_state_enum_t;
-
 /* DHCP op codes */
 #define DHCP_BOOTREQUEST            1
 #define DHCP_BOOTREPLY              2
@@ -172,7 +166,7 @@ typedef enum {
 #define DHCP_OPTION_T2              59 /* T2 rebinding time */
 #define DHCP_OPTION_US              60
 #define DHCP_OPTION_CLIENT_ID       61
-#define DHCP_OPTION_TFTP_SERVERNAME 66  
+#define DHCP_OPTION_TFTP_SERVERNAME 66
 #define DHCP_OPTION_BOOTFILE        67
 
 /* possible combinations of overloading the file and sname fields with options */
diff --git a/src/include/lwip/prot/dns.h b/src/include/lwip/prot/dns.h
index 9998fb60..0a99ab0c 100644
--- a/src/include/lwip/prot/dns.h
+++ b/src/include/lwip/prot/dns.h
@@ -42,7 +42,7 @@
 
 #include "lwip/arch.h"
 
-#ifdef	__cplusplus
+#ifdef __cplusplus
 extern "C" {
 #endif
 
@@ -114,18 +114,9 @@ PACK_STRUCT_END
 #  include "arch/epstruct.h"
 #endif
 #define SIZEOF_DNS_HDR 12
-        
-/* DNS protocol states */
-typedef enum {
-  DNS_STATE_UNUSED           = 0,
-  DNS_STATE_NEW              = 1,
-  DNS_STATE_ASKING           = 2,
-  DNS_STATE_DONE             = 3
-} dns_state_enum_t;
 
-#ifdef	__cplusplus
+#ifdef __cplusplus
 }
 #endif
 
-#endif	/* LWIP_HDR_PROT_DNS_H */
-
+#endif /* LWIP_HDR_PROT_DNS_H */
diff --git a/src/include/lwip/prot/icmp.h b/src/include/lwip/prot/icmp.h
index b0005a6b..7d19385c 100644
--- a/src/include/lwip/prot/icmp.h
+++ b/src/include/lwip/prot/icmp.h
@@ -78,10 +78,9 @@ PACK_STRUCT_END
 #  include "arch/epstruct.h"
 #endif
 
+/* Compatibility defines, old versions used to combine type and code to an u16_t */
 #define ICMPH_TYPE(hdr) ((hdr)->type)
 #define ICMPH_CODE(hdr) ((hdr)->code)
-
-/** Combines type and code to an u16_t */
 #define ICMPH_TYPE_SET(hdr, t) ((hdr)->type = (t))
 #define ICMPH_CODE_SET(hdr, c) ((hdr)->code = (c))