sizeof(mtu_info));sin= (struct sockaddr_in6 *)msg->msg_name;if(sin) {sin->sin6_family = AF_INET6;sin->sin6_flowinfo =0;sin->sin6_port =0;sin->sin6_scope_id = mtu_info.ip6m_addr.sin6_scope_id;ipv6_addr_copy(&sin->sin6_addr, &mtu_info.ip6m_addr.sin6_addr);...