Checklist

• My issue is specific & actionable.
• I am not suggesting a protocol enhancement.
• I have searched on the issue tracker for my issue.

Description

Currently a host can send an unsolicited message to a remote peer, causing the remote peer to designate the host as a broadcast recipient.

This is no worse than before broadcast control, but it can negate the benefits of broadcast control, and is not currently stopped by the broadcasting host that is affected.

A broadcasting host should ignore unsolicited bitswap messages from others, so as to retain control of who broadcasts are sent to.

Security implications

There are no more security implications than there were before broadcast control was introduced, when all peers received broadcasts. The network's data is publicly discoverable, so secrecy must be achieved by other means such as encryption.