1 files changed, 198 insertions, 0 deletions
diff --git a/lib/ngtcp2_pv.h b/lib/ngtcp2_pv.h
new file mode 100644
index 0000000..293cbca
--- /dev/null
+++ b/lib/ngtcp2_pv.h
@@ -0,0 +1,198 @@
+/*
+ * 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 */