net: socket: Fix recvmsg() pktinfo support.

Fix an issue where IPV6_RECVPKTINFO was used instead of IPV6_PKTINFO
when insert_pktinfo was called.

Signed-off-by: Cristian Bulacu <[email protected]>

Author: Cristib05

include/zephyr/net/socket.h

@@ -1092,6 +1092,9 @@ struct ipv6_mreq {
  */
 #define IPV6_RECVPKTINFO 49
 
+/** Option which returns an in6_pktinfo structure in ancillary data */
+#define IPV6_PKTINFO 50
+
 /** Pass an IPV6_RECVHOPLIMIT ancillary message that contains information
  *  about the hop limit of the incoming packet. See RFC 3542.
  */

subsys/net/lib/sockets/sockets_inet.c

@@ -1050,7 +1050,7 @@ static int add_pktinfo(struct net_context *ctx,
 		net_ipv6_addr_copy_raw((uint8_t *)&info.ipi6_addr, ipv6_hdr->dst);
 		info.ipi6_ifindex = ctx->iface;
 
-		ret = insert_pktinfo(msg, IPPROTO_IPV6, IPV6_RECVPKTINFO,
+		ret = insert_pktinfo(msg, IPPROTO_IPV6, IPV6_PKTINFO,
 				     &info, sizeof(info));
 
 		goto out;