al-Lyth bin Abi Sulaym الليث بن أبي سليم · The Chapters on Marriage

Ibn Umar said: “The Messenger of Allah forbade Shighar. Shighar is when a man says to another man: 'Marry your daughter or sister to me, on condition that I will marry my daughter or sister to you,' and they do not give any dower (i.e. neither of them give other the dower).”