Fix message_buffer under-allocation in receive_messages#305
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caniko wants to merge 2 commits intoNoxime:masterfrom
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Fix message_buffer under-allocation in receive_messages#305caniko wants to merge 2 commits intoNoxime:masterfrom
caniko wants to merge 2 commits intoNoxime:masterfrom
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Currently `send_messages()` is only available on `ListenSocket`, but the underlying C++ API `ISteamNetworkingSockets::SendMessages()` is a top-level interface method that works with any connection handle. This means P2P dial-side connections (from `connect_p2p()`) have no way to use the efficient batched send path with per-message channel/lane tagging — the dialer never gets a `ListenSocket`, only a `NetConnection`. This is needed to use connection lanes (`ConfigureConnectionLanes`) from both sides of a P2P connection. Without it you can configure lanes but only the listener can actually send on them. The implementation is identical to `ListenSocket::send_messages()` — both structs hold the same `*mut ISteamNetworkingSockets` pointer, just in different fields. Closes Noxime#302
`Vec::reserve(additional)` ensures `capacity >= len + additional`, not `capacity >= capacity + additional`. When the buffer had some leftover capacity (0 < capacity < batch_size), the old expression `reserve(batch_size - capacity)` would guarantee only `capacity >= batch_size - old_capacity`, which is less than batch_size. The Steam API could then write past the allocated region. Pass `batch_size` directly so the guarantee becomes `capacity >= 0 + batch_size = batch_size`, which is correct since the buffer is always drained between calls (len == 0).
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What
Fixes a buffer under-allocation bug in
NetConnection::receive_messages,receive_messages_into, andNetPollGroup::receive_messages.Why
The old code did
reserve(batch_size - capacity), butVec::reserve(additional)guaranteescapacity >= len + additional— notcapacity + additional. When the internal message buffer had some leftover capacity but less thanbatch_size, the reservation fell short. The Steam API could then write messages beyond the allocated region, causing undefined behavior.Since the buffer is always drained between calls (
len == 0), passingbatch_sizedirectly gives the correct guarantee:capacity >= batch_size.Changes
Three call sites, same one-line fix each — replaced
reserve(batch_size - capacity)withreserve(batch_size).