diff options
author | Hugo Landau <hlandau@openssl.org> | 2023-04-18 19:30:56 +0100 |
---|---|---|
committer | Hugo Landau <hlandau@openssl.org> | 2023-05-12 14:47:13 +0100 |
commit | 0847e63ee5d58d824390aadcbcf10281c45900c4 (patch) | |
tree | 5dfd6836eb30316eb68fa0ea8c5d538cc27d9874 /include | |
parent | 9cacba434b027bc6f3a3f3c4255c2453935e5357 (diff) |
QUIC QSM: Stream garbage collection
This allows QUIC_STREAM objects to be deleted when they are no longer
needed.
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/20765)
Diffstat (limited to 'include')
-rw-r--r-- | include/internal/quic_stream.h | 6 | ||||
-rw-r--r-- | include/internal/quic_stream_map.h | 119 |
2 files changed, 124 insertions, 1 deletions
diff --git a/include/internal/quic_stream.h b/include/internal/quic_stream.h index 42d6ed2d7d..a1e88a4ab6 100644 --- a/include/internal/quic_stream.h +++ b/include/internal/quic_stream.h @@ -254,6 +254,12 @@ void ossl_quic_sstream_fin(QUIC_SSTREAM *qss); int ossl_quic_sstream_get_final_size(QUIC_SSTREAM *qss, uint64_t *final_size); /* + * Returns 1 iff all bytes (and any FIN, if any) which have been appended to the + * QUIC_SSTREAM so far, and any FIN (if any), have been both sent and acked. + */ +int ossl_quic_sstream_is_totally_acked(QUIC_SSTREAM *qss); + +/* * Resizes the internal ring buffer. All stream data is preserved safely. * * This can be used to expand or contract the ring buffer, but not to contract diff --git a/include/internal/quic_stream_map.h b/include/internal/quic_stream_map.h index 0f2732a6fc..5d21c60185 100644 --- a/include/internal/quic_stream_map.h +++ b/include/internal/quic_stream_map.h @@ -37,6 +37,7 @@ struct quic_stream_list_node_st { struct quic_stream_st { QUIC_STREAM_LIST_NODE active_node; /* for use by QUIC_STREAM_MAP */ QUIC_STREAM_LIST_NODE accept_node; /* accept queue of remotely-created streams */ + QUIC_STREAM_LIST_NODE ready_for_gc_node; /* queue of streams now ready for GC */ /* Temporary link used by TXP. */ QUIC_STREAM *txp_next; @@ -119,8 +120,117 @@ struct quic_stream_st { /* A FIN has been retired from the rstream buffer. */ unsigned int recv_fin_retired : 1; - /* The stream's XSO has been deleted. Pending GC. */ + /* + * The stream's XSO has been deleted. Pending GC. + * + * Here is how stream deletion works: + * + * - A QUIC_STREAM cannot be deleted until it is neither in the accept + * queue nor has an associated XSO. This condition occurs when and only + * when deleted is true. + * + * - Once there is the case (i.e., no user-facing API object exposing the + * stream), we can delete the stream once we determine that all of our + * protocol obligations requiring us to keep the QUIC_STREAM around have + * been met. + * + * The following frames relate to the streams layer for a specific + * stream: + * + * STREAM + * + * RX Obligations: + * Ignore for a deleted stream. + * + * (This is different from our obligation for a + * locally-initiated stream ID we have not created yet, + * which we must treat as a protocol error. This can be + * distinguished via a simple monotonic counter.) + * + * TX Obligations: + * None, once we've decided to (someday) delete the stream. + * + * STOP_SENDING + * + * We cannot delete the stream until we have finished informing + * the peer that we are not going to be listening to it + * anymore. + * + * RX Obligations: + * When we delete a stream we must have already had a FIN + * or RESET_STREAM we transmitted acknowledged by the peer. + * Thus we can ignore STOP_SENDING frames for deleted + * streams (if they occur, they are probably just + * retransmissions). + * + * TX Obligations: + * _Acknowledged_ receipt of a STOP_SENDING frame by the + * peer (unless the peer's send part has already FIN'd). + * + * RESET_STREAM + * + * We cannot delete the stream until we have finished informing + * the peer that we are not going to be transmitting on it + * anymore. + * + * RX Obligations: + * This indicates the peer is not going to send any more + * data on the stream. We don't need to care about this + * since once a stream is marked for deletion we don't care + * about any data it does send. We can ignore this for + * deleted streams. The important criterion is that the + * peer has been successfully delivered our STOP_SENDING + * frame. + * + * TX Obligations: + * _Acknowledged_ receipt of a RESET_STREAM frame or FIN by + * the peer. + * + * MAX_STREAM_DATA + * + * RX Obligations: + * Ignore. Since we are not going to be sending any more + * data on a stream once it has been marked for deletion, + * we don't need to care about flow control information. + * + * TX Obligations: + * None. + * + * In other words, our protocol obligation is simply: + * + * - either: + * - the peer has acknowledged receipt of a STOP_SENDING frame sent + * by us; -or- + * - we have received a FIN and all preceding segments from the peer + * + * [NOTE: The actual criterion required here is simply 'we have + * received a FIN from the peer'. However, due to reordering and + * retransmissions we might subsequently receive non-FIN segments + * out of order. The FIN means we know the peer will stop + * transmitting on the stream at *some* point, but by sending + * STOP_SENDING we can avoid these needless retransmissions we + * will just ignore anyway. In actuality we could just handle all + * cases by sending a STOP_SENDING. The strategy we choose is to + * only avoid sending a STOP_SENDING and rely on a received FIN + * when we have received all preceding data, as this makes it + * reasonably certain no benefit would be gained by sending + * STOP_SENDING.] + * + * TODO(QUIC): Implement the latter case (currently we just + * always do STOP_SENDING). + * + * and; + * + * - we have drained our send stream (for a finished send stream) + * and got acknowledgement all parts of it including the FIN, or + * sent a RESET_STREAM frame and got acknowledgement of that frame. + * + * Once these conditions are met, we can GC the QUIC_STREAM. + * + */ unsigned int deleted : 1; + /* Set to 1 once the above conditions are actually met. */ + unsigned int ready_for_gc : 1; }; /* @@ -138,6 +248,7 @@ typedef struct quic_stream_map_st { LHASH_OF(QUIC_STREAM) *map; QUIC_STREAM_LIST_NODE active_list; QUIC_STREAM_LIST_NODE accept_list; + QUIC_STREAM_LIST_NODE ready_for_gc_list; size_t rr_stepping, rr_counter, num_accept; QUIC_STREAM *rr_cur; uint64_t (*get_stream_limit_cb)(int uni, void *arg); @@ -288,6 +399,12 @@ void ossl_quic_stream_map_remove_from_accept_queue(QUIC_STREAM_MAP *qsm, size_t ossl_quic_stream_map_get_accept_queue_len(QUIC_STREAM_MAP *qsm); /* + * Delete streams ready for GC. Pointers to those QUIC_STREAM objects become + * invalid. + */ +void ossl_quic_stream_map_gc(QUIC_STREAM_MAP *qsm); + +/* * QUIC Stream Iterator * ==================== * |