From 4b45baee101b02f29143c22db92f33162edb1ece Mon Sep 17 00:00:00 2001
From: Dirk Ziegelmeier <dirk@ziegelmeier.net>
Date: Fri, 26 Aug 2016 15:58:18 +0200
Subject: [PATCH] Add some dual-stack notes to documentation

---
 src/core/raw.c             | 2 ++
 src/core/tcp.c             | 2 ++
 src/core/udp.c             | 2 ++
 src/include/lwip/ip_addr.h | 6 +++++-
 4 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/core/raw.c b/src/core/raw.c
index efa21f90..a3a90778 100644
--- a/src/core/raw.c
+++ b/src/core/raw.c
@@ -472,6 +472,8 @@ raw_new(u8_t proto)
  * could not be allocated.
  *
  * @param type IP address type, see IPADDR_TYPE_XX definitions.
+ * If you want to listen to IPv4 and IPv6 (dual-stack) packets,
+ * supply @ref IPADDR_TYPE_ANY as argument and bind to @ref IP_ANY_TYPE.
  * @param proto the protocol number (next header) of the IPv6 packet payload
  *              (e.g. IP6_NEXTH_ICMP6)
  *
diff --git a/src/core/tcp.c b/src/core/tcp.c
index 7f15c04c..64eef699 100644
--- a/src/core/tcp.c
+++ b/src/core/tcp.c
@@ -1603,6 +1603,8 @@ tcp_new(void)
  * The pcb is not put on any list until binding using tcp_bind().
  *
  * @param type IP address type, see IPADDR_TYPE_XX definitions.
+ * If you want to listen to IPv4 and IPv6 (dual-stack) connections,
+ * supply @ref IPADDR_TYPE_ANY as argument and bind to @ref IP_ANY_TYPE.
  * @return a new tcp_pcb that initially is in state CLOSED
  */
 struct tcp_pcb *
diff --git a/src/core/udp.c b/src/core/udp.c
index 04a64537..60d3f4a6 100644
--- a/src/core/udp.c
+++ b/src/core/udp.c
@@ -1145,6 +1145,8 @@ udp_new(void)
  * Create a UDP PCB for specific IP type.
  *
  * @param type IP address type, see IPADDR_TYPE_XX definitions.
+ * If you want to listen to IPv4 and IPv6 (dual-stack) packets,
+ * supply @ref IPADDR_TYPE_ANY as argument and bind to @ref IP_ANY_TYPE.
  * @return The UDP PCB which was created. NULL if the PCB data structure
  * could not be allocated.
  *
diff --git a/src/include/lwip/ip_addr.h b/src/include/lwip/ip_addr.h
index 5523ee02..4b13e702 100644
--- a/src/include/lwip/ip_addr.h
+++ b/src/include/lwip/ip_addr.h
@@ -47,9 +47,13 @@
 extern "C" {
 #endif
 
-/** These are the values for ip_addr_t.type */
+/** Value for ip_addr_t.type: IPv4 */
 #define IPADDR_TYPE_V4                0U
+/** Value for ip_addr_t.type: IPv6 */
 #define IPADDR_TYPE_V6                6U
+/** Value for ip_addr_t.type: IPv4+IPv6 ("dual-stack")
+ * @see tcp_new_ip_type(), udp_new_ip_type(), raw_new_ip_type().
+ */
 #define IPADDR_TYPE_ANY               46U
 
 #if LWIP_IPV4 && LWIP_IPV6