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-rw-r--r--lib/ngtcp2_pv.h198
1 files changed, 198 insertions, 0 deletions
diff --git a/lib/ngtcp2_pv.h b/lib/ngtcp2_pv.h
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+/*
+ * ngtcp2
+ *
+ * Copyright (c) 2019 ngtcp2 contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#ifndef NGTCP2_PV_H
+#define NGTCP2_PV_H
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif /* HAVE_CONFIG_H */
+
+#include <ngtcp2/ngtcp2.h>
+
+#include "ngtcp2_cid.h"
+#include "ngtcp2_ringbuf.h"
+
+/* NGTCP2_PV_MAX_ENTRIES is the maximum number of entries that
+ ngtcp2_pv can contain. It must be power of 2. */
+#define NGTCP2_PV_MAX_ENTRIES 8
+/* NGTCP2_PV_NUM_PROBE_PKT is the number of probe packets containing
+ PATH_CHALLENGE sent at a time. */
+#define NGTCP2_PV_NUM_PROBE_PKT 2
+
+typedef struct ngtcp2_log ngtcp2_log;
+
+typedef struct ngtcp2_frame_chain ngtcp2_frame_chain;
+
+/* NGTCP2_PV_ENTRY_FLAG_NONE indicates that no flag is set. */
+#define NGTCP2_PV_ENTRY_FLAG_NONE 0x00u
+/* NGTCP2_PV_ENTRY_FLAG_UNDERSIZED indicates that UDP datagram which
+ contains PATH_CHALLENGE is undersized (< 1200 bytes) */
+#define NGTCP2_PV_ENTRY_FLAG_UNDERSIZED 0x01u
+
+typedef struct ngtcp2_pv_entry {
+ /* expiry is the timestamp when this PATH_CHALLENGE expires. */
+ ngtcp2_tstamp expiry;
+ /* flags is zero or more of NGTCP2_PV_ENTRY_FLAG_*. */
+ uint8_t flags;
+ /* data is a byte string included in PATH_CHALLENGE. */
+ uint8_t data[8];
+} ngtcp2_pv_entry;
+
+void ngtcp2_pv_entry_init(ngtcp2_pv_entry *pvent, const uint8_t *data,
+ ngtcp2_tstamp expiry, uint8_t flags);
+
+/* NGTCP2_PV_FLAG_NONE indicates no flag is set. */
+#define NGTCP2_PV_FLAG_NONE 0x00u
+/* NGTCP2_PV_FLAG_DONT_CARE indicates that the outcome of path
+ validation should be ignored entirely. */
+#define NGTCP2_PV_FLAG_DONT_CARE 0x01u
+/* NGTCP2_PV_FLAG_CANCEL_TIMER indicates that the expiry timer is
+ cancelled. */
+#define NGTCP2_PV_FLAG_CANCEL_TIMER 0x02u
+/* NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE indicates that fallback DCID is
+ available in ngtcp2_pv. If path validation fails, fallback to the
+ fallback DCID. If path validation succeeds, fallback DCID is
+ retired if it does not equal to the current DCID. */
+#define NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE 0x04u
+/* NGTCP2_PV_FLAG_MTU_PROBE indicates that a validation must probe
+ least MTU that QUIC requires, which is 1200 bytes. If it fails, a
+ path is not viable. */
+#define NGTCP2_PV_FLAG_MTU_PROBE 0x08u
+/* NGTCP2_PV_FLAG_PREFERRED_ADDR indicates that client is migrating to
+ server's preferred address. This flag is only used by client. */
+#define NGTCP2_PV_FLAG_PREFERRED_ADDR 0x10u
+
+typedef struct ngtcp2_pv ngtcp2_pv;
+
+ngtcp2_static_ringbuf_def(pv_ents, NGTCP2_PV_MAX_ENTRIES,
+ sizeof(ngtcp2_pv_entry));
+/*
+ * ngtcp2_pv is the context of a single path validation.
+ */
+struct ngtcp2_pv {
+ const ngtcp2_mem *mem;
+ ngtcp2_log *log;
+ /* dcid is DCID and path this path validation uses. */
+ ngtcp2_dcid dcid;
+ /* fallback_dcid is the usually validated DCID and used as a
+ fallback if this path validation fails. */
+ ngtcp2_dcid fallback_dcid;
+ /* ents is the ring buffer of ngtcp2_pv_entry */
+ ngtcp2_static_ringbuf_pv_ents ents;
+ /* timeout is the duration within which this path validation should
+ succeed. */
+ ngtcp2_duration timeout;
+ /* fallback_pto is PTO of fallback connection. */
+ ngtcp2_duration fallback_pto;
+ /* started_ts is the timestamp this path validation starts. */
+ ngtcp2_tstamp started_ts;
+ /* round is the number of times that probe_pkt_left is reset. */
+ size_t round;
+ /* probe_pkt_left is the number of probe packets containing
+ PATH_CHALLENGE which can be send without waiting for an
+ expiration of a previous flight. */
+ size_t probe_pkt_left;
+ /* flags is bitwise-OR of zero or more of NGTCP2_PV_FLAG_*. */
+ uint8_t flags;
+};
+
+/*
+ * ngtcp2_pv_new creates new ngtcp2_pv object and assigns its pointer
+ * to |*ppv|. This function makes a copy of |dcid|. |timeout| is a
+ * duration within which this path validation must succeed.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * NGTCP2_ERR_NOMEM
+ * Out of memory
+ */
+int ngtcp2_pv_new(ngtcp2_pv **ppv, const ngtcp2_dcid *dcid,
+ ngtcp2_duration timeout, uint8_t flags, ngtcp2_log *log,
+ const ngtcp2_mem *mem);
+
+/*
+ * ngtcp2_pv_del deallocates |pv|. This function frees memory |pv|
+ * points too.
+ */
+void ngtcp2_pv_del(ngtcp2_pv *pv);
+
+/*
+ * ngtcp2_pv_add_entry adds new entry with |data|. |expiry| is the
+ * expiry time of the entry.
+ */
+void ngtcp2_pv_add_entry(ngtcp2_pv *pv, const uint8_t *data,
+ ngtcp2_tstamp expiry, uint8_t flags, ngtcp2_tstamp ts);
+
+/*
+ * ngtcp2_pv_full returns nonzero if |pv| is full of ngtcp2_pv_entry.
+ */
+int ngtcp2_pv_full(ngtcp2_pv *pv);
+
+/*
+ * ngtcp2_pv_validate validates that the received |data| matches the
+ * one of the existing entry. The flag of ngtcp2_pv_entry that
+ * matches |data| is assigned to |*pflags| if this function succeeds.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * NGTCP2_ERR_PATH_VALIDATION_FAILED
+ * path validation has failed and must be abandoned
+ * NGTCP2_ERR_INVALID_STATE
+ * |pv| includes no entry
+ * NGTCP2_ERR_INVALID_ARGUMENT
+ * |pv| does not have an entry which has |data| and |path|
+ */
+int ngtcp2_pv_validate(ngtcp2_pv *pv, uint8_t *pflags, const uint8_t *data);
+
+/*
+ * ngtcp2_pv_handle_entry_expiry checks expiry of existing entries.
+ */
+void ngtcp2_pv_handle_entry_expiry(ngtcp2_pv *pv, ngtcp2_tstamp ts);
+
+/*
+ * ngtcp2_pv_should_send_probe returns nonzero if new entry can be
+ * added by ngtcp2_pv_add_entry.
+ */
+int ngtcp2_pv_should_send_probe(ngtcp2_pv *pv);
+
+/*
+ * ngtcp2_pv_validation_timed_out returns nonzero if the path
+ * validation fails because of timeout.
+ */
+int ngtcp2_pv_validation_timed_out(ngtcp2_pv *pv, ngtcp2_tstamp ts);
+
+/*
+ * ngtcp2_pv_next_expiry returns the earliest expiry.
+ */
+ngtcp2_tstamp ngtcp2_pv_next_expiry(ngtcp2_pv *pv);
+
+/*
+ * ngtcp2_pv_cancel_expired_timer cancels the expired timer.
+ */
+void ngtcp2_pv_cancel_expired_timer(ngtcp2_pv *pv, ngtcp2_tstamp ts);
+
+#endif /* NGTCP2_PV_H */