From af1da5e047c9e7ba8562a32336163e27d9bf152d Mon Sep 17 00:00:00 2001
From: "chao.an" <anchao@xiaomi.com>
Date: Wed, 2 Dec 2020 13:41:22 +0800
Subject: [PATCH] net/igmp: add MULTICAST_TTL support

Change-Id: Ic8c9a4f4f9b1ebf9858fa5368c6c75e949de6800
Signed-off-by: chao.an <anchao@xiaomi.com>
---
 net/inet/ipv4_setsockopt.c | 32 +++++++++++++++++++++++++++-----
 1 file changed, 27 insertions(+), 5 deletions(-)

diff --git a/net/inet/ipv4_setsockopt.c b/net/inet/ipv4_setsockopt.c
index 11438bda370..995b750b113 100644
--- a/net/inet/ipv4_setsockopt.c
+++ b/net/inet/ipv4_setsockopt.c
@@ -51,6 +51,7 @@
 #include "netdev/netdev.h"
 #include "igmp/igmp.h"
 #include "inet/inet.h"
+#include "udp/udp.h"
 
 #ifdef CONFIG_NET_IPv4
 
@@ -187,19 +188,40 @@ int ipv4_setsockopt(FAR struct socket *psock, int option,
             }
         }
         break;
+
       case IP_MULTICAST_TTL:          /* Set/read the time-to-live value of
                                        * outgoing multicast packets */
-      case IP_MULTICAST_LOOP:         /* Set/read boolean that determines
-                                       * whether sent multicast packets
-                                       * should be looped back to local
-                                       * sockets. */
         {
-          ret = OK;
+          if (psock->s_type != SOCK_DGRAM ||
+              value_len != sizeof(int))
+            {
+              ret = -EINVAL;
+            }
+          else
+            {
+              FAR struct udp_conn_s *conn;
+              int ttl = *(FAR int *)value;
+
+              if (ttl <= 0 || ttl > 255)
+                {
+                  ret = -EINVAL;
+                }
+              else
+                {
+                  conn = (FAR struct udp_conn_s *)psock->s_conn;
+                  conn->ttl = ttl;
+                  ret = OK;
+                }
+            }
         }
         break;
 
       /* The following IPv4 socket options are defined, but not implemented */
 
+      case IP_MULTICAST_LOOP:         /* Set/read boolean that determines
+                                       * whether sent multicast packets
+                                       * should be looped back to local
+                                       * sockets. */
       case IP_MULTICAST_IF:           /* Set local device for a multicast
                                        * socket */
       case IP_UNBLOCK_SOURCE:         /* Unblock previously blocked multicast