http_static: cleanup file handler and cache

Type: refactor

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: I7aff3a02315f9f92039dd2e3af1cbd8312aec662

1 files changed, 450 insertions, 0 deletions

diff --git a/src/plugins/http_static/http_cache.c b/src/plugins/http_static/http_cache.c
new file mode 100644
index 00000000000..8b9751b7f78
--- /dev/null
+++ b/src/plugins/http_static/http_cache.c
@@ -0,0 +1,450 @@
+/*
+ * Copyright (c) 2022 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <http_static/http_cache.h>
+#include <vppinfra/bihash_template.c>
+#include <vppinfra/unix.h>
+#include <vlib/vlib.h>
+
+static void
+hss_cache_lock (hss_cache_t *hc)
+{
+  clib_spinlock_lock (&hc->cache_lock);
+}
+
+static void
+hss_cache_unlock (hss_cache_t *hc)
+{
+  clib_spinlock_unlock (&hc->cache_lock);
+}
+
+/** \brief Sanity-check the forward and reverse LRU lists
+ */
+static inline void
+lru_validate (hss_cache_t *hc)
+{
+#if CLIB_DEBUG > 0
+  f64 last_timestamp;
+  u32 index;
+  int i;
+  hss_cache_entry_t *ce;
+
+  last_timestamp = 1e70;
+  for (i = 1, index = hc->first_index; index != ~0;)
+    {
+      ce = pool_elt_at_index (hc->cache_pool, index);
+      /* Timestamps should be smaller (older) as we walk the fwd list */
+      if (ce->last_used > last_timestamp)
+	{
+	  clib_warning ("%d[%d]: last used %.6f, last_timestamp %.6f", index,
+			i, ce->last_used, last_timestamp);
+	}
+      index = ce->next_index;
+      last_timestamp = ce->last_used;
+      i++;
+    }
+
+  last_timestamp = 0.0;
+  for (i = 1, index = hc->last_index; index != ~0;)
+    {
+      ce = pool_elt_at_index (hc->cache_pool, index);
+      /* Timestamps should be larger (newer) as we walk the rev list */
+      if (ce->last_used < last_timestamp)
+	{
+	  clib_warning ("%d[%d]: last used %.6f, last_timestamp %.6f", index,
+			i, ce->last_used, last_timestamp);
+	}
+      index = ce->prev_index;
+      last_timestamp = ce->last_used;
+      i++;
+    }
+#endif
+}
+
+/** \brief Remove a data cache entry from the LRU lists
+ */
+static inline void
+lru_remove (hss_cache_t *hc, hss_cache_entry_t *ce)
+{
+  hss_cache_entry_t *next_ep, *prev_ep;
+  u32 ce_index;
+
+  lru_validate (hc);
+
+  ce_index = ce - hc->cache_pool;
+
+  /* Deal with list heads */
+  if (ce_index == hc->first_index)
+    hc->first_index = ce->next_index;
+  if (ce_index == hc->last_index)
+    hc->last_index = ce->prev_index;
+
+  /* Fix next->prev */
+  if (ce->next_index != ~0)
+    {
+      next_ep = pool_elt_at_index (hc->cache_pool, ce->next_index);
+      next_ep->prev_index = ce->prev_index;
+    }
+  /* Fix prev->next */
+  if (ce->prev_index != ~0)
+    {
+      prev_ep = pool_elt_at_index (hc->cache_pool, ce->prev_index);
+      prev_ep->next_index = ce->next_index;
+    }
+  lru_validate (hc);
+}
+
+/** \brief Add an entry to the LRU lists, tag w/ supplied timestamp
+ */
+static inline void
+lru_add (hss_cache_t *hc, hss_cache_entry_t *ce, f64 now)
+{
+  hss_cache_entry_t *next_ce;
+  u32 ce_index;
+
+  lru_validate (hc);
+
+  ce_index = ce - hc->cache_pool;
+
+  /*
+   * Re-add at the head of the forward LRU list,
+   * tail of the reverse LRU list
+   */
+  if (hc->first_index != ~0)
+    {
+      next_ce = pool_elt_at_index (hc->cache_pool, hc->first_index);
+      next_ce->prev_index = ce_index;
+    }
+
+  ce->prev_index = ~0;
+
+  /* ep now the new head of the LRU forward list */
+  ce->next_index = hc->first_index;
+  hc->first_index = ce_index;
+
+  /* single session case: also the tail of the reverse LRU list */
+  if (hc->last_index == ~0)
+    hc->last_index = ce_index;
+  ce->last_used = now;
+
+  lru_validate (hc);
+}
+
+/** \brief Remove and re-add a cache entry from/to the LRU lists
+ */
+static inline void
+lru_update (hss_cache_t *hc, hss_cache_entry_t *ep, f64 now)
+{
+  lru_remove (hc, ep);
+  lru_add (hc, ep, now);
+}
+
+static void
+hss_cache_attach_entry (hss_cache_t *hc, u32 ce_index, u8 **data,
+			u64 *data_len)
+{
+  hss_cache_entry_t *ce;
+
+  /* Expect ce_index to be validated outside */
+  ce = pool_elt_at_index (hc->cache_pool, ce_index);
+  ce->inuse++;
+  *data = ce->data;
+  *data_len = vec_len (ce->data);
+
+  /* Update the cache entry, mark it in-use */
+  lru_update (hc, ce, vlib_time_now (vlib_get_main ()));
+
+  if (hc->debug_level > 1)
+    clib_warning ("index %d refcnt now %d", ce_index, ce->inuse);
+}
+
+/** \brief Detach cache entry from session
+ */
+void
+hss_cache_detach_entry (hss_cache_t *hc, u32 ce_index)
+{
+  hss_cache_entry_t *ce;
+
+  hss_cache_lock (hc);
+
+  ce = pool_elt_at_index (hc->cache_pool, ce_index);
+  ce->inuse--;
+
+  if (hc->debug_level > 1)
+    clib_warning ("index %d refcnt now %d", ce_index, ce->inuse);
+
+  hss_cache_unlock (hc);
+}
+
+static u32
+hss_cache_lookup (hss_cache_t *hc, u8 *path)
+{
+  BVT (clib_bihash_kv) kv;
+  int rv;
+
+  kv.key = (u64) path;
+  kv.value = ~0;
+
+  /* Value updated only if lookup succeeds */
+  rv = BV (clib_bihash_search) (&hc->name_to_data, &kv, &kv);
+  ASSERT (!rv || kv.value == ~0);
+
+  if (hc->debug_level > 1)
+    clib_warning ("lookup '%s' %s", kv.key, kv.value == ~0 ? "fail" : "found");
+
+  return kv.value;
+}
+
+u32
+hss_cache_lookup_and_attach (hss_cache_t *hc, u8 *path, u8 **data,
+			     u64 *data_len)
+{
+  u32 ce_index;
+
+  /* Make sure nobody removes the entry while we look it up */
+  hss_cache_lock (hc);
+
+  ce_index = hss_cache_lookup (hc, path);
+  if (ce_index != ~0)
+    hss_cache_attach_entry (hc, ce_index, data, data_len);
+
+  hss_cache_unlock (hc);
+
+  return ce_index;
+}
+
+static void
+hss_cache_do_evictions (hss_cache_t *hc)
+{
+  BVT (clib_bihash_kv) kv;
+  hss_cache_entry_t *ce;
+  u32 free_index;
+
+  free_index = hc->last_index;
+
+  while (free_index != ~0)
+    {
+      /* pick the LRU */
+      ce = pool_elt_at_index (hc->cache_pool, free_index);
+      /* Which could be in use... */
+      if (ce->inuse)
+	{
+	  if (hc->debug_level > 1)
+	    clib_warning ("index %d in use refcnt %d", free_index, ce->inuse);
+	}
+      free_index = ce->prev_index;
+      kv.key = (u64) (ce->filename);
+      kv.value = ~0ULL;
+      if (BV (clib_bihash_add_del) (&hc->name_to_data, &kv, 0 /* is_add */) <
+	  0)
+	{
+	  clib_warning ("LRU delete '%s' FAILED!", ce->filename);
+	}
+      else if (hc->debug_level > 1)
+	clib_warning ("LRU delete '%s' ok", ce->filename);
+
+      lru_remove (hc, ce);
+      hc->cache_size -= vec_len (ce->data);
+      hc->cache_evictions++;
+      vec_free (ce->filename);
+      vec_free (ce->data);
+
+      if (hc->debug_level > 1)
+	clib_warning ("pool put index %d", ce - hc->cache_pool);
+
+      pool_put (hc->cache_pool, ce);
+      if (hc->cache_size < hc->cache_limit)
+	break;
+    }
+}
+
+u32
+hss_cache_add_and_attach (hss_cache_t *hc, u8 *path, u8 **data, u64 *data_len)
+{
+  BVT (clib_bihash_kv) kv;
+  hss_cache_entry_t *ce;
+  clib_error_t *error;
+  u8 *file_data;
+  u32 ce_index;
+
+  hss_cache_lock (hc);
+
+  /* Need to recycle one (or more cache) entries? */
+  if (hc->cache_size > hc->cache_limit)
+    hss_cache_do_evictions (hc);
+
+  /* Read the file */
+  error = clib_file_contents ((char *) path, &file_data);
+  if (error)
+    {
+      clib_warning ("Error reading '%s'", path);
+      clib_error_report (error);
+      return ~0;
+    }
+
+  /* Create a cache entry for it */
+  pool_get_zero (hc->cache_pool, ce);
+  ce->filename = vec_dup (path);
+  ce->data = file_data;
+
+  /* Attach cache entry without additional lock */
+  ce->inuse++;
+  *data = file_data;
+  *data_len = vec_len (file_data);
+  lru_add (hc, ce, vlib_time_now (vlib_get_main ()));
+
+  hc->cache_size += vec_len (ce->data);
+  ce_index = ce - hc->cache_pool;
+
+  if (hc->debug_level > 1)
+    clib_warning ("index %d refcnt now %d", ce_index, ce->inuse);
+
+  /* Add to the lookup table */
+
+  kv.key = (u64) vec_dup (path);
+  kv.value = ce_index;
+
+  if (hc->debug_level > 1)
+    clib_warning ("add '%s' value %lld", kv.key, kv.value);
+
+  if (BV (clib_bihash_add_del) (&hc->name_to_data, &kv, 1 /* is_add */) < 0)
+    {
+      clib_warning ("BUG: add failed!");
+    }
+
+  hss_cache_unlock (hc);
+
+  return ce_index;
+}
+
+u32
+hss_cache_clear (hss_cache_t *hc)
+{
+  u32 free_index, busy_items = 0;
+  hss_cache_entry_t *ce;
+  BVT (clib_bihash_kv) kv;
+
+  hss_cache_lock (hc);
+
+  /* Walk the LRU list to find active entries */
+  free_index = hc->last_index;
+  while (free_index != ~0)
+    {
+      ce = pool_elt_at_index (hc->cache_pool, free_index);
+      free_index = ce->prev_index;
+      /* Which could be in use... */
+      if (ce->inuse)
+	{
+	  busy_items++;
+	  free_index = ce->next_index;
+	  continue;
+	}
+      kv.key = (u64) (ce->filename);
+      kv.value = ~0ULL;
+      if (BV (clib_bihash_add_del) (&hc->name_to_data, &kv, 0 /* is_add */) <
+	  0)
+	{
+	  clib_warning ("BUG: cache clear delete '%s' FAILED!", ce->filename);
+	}
+
+      lru_remove (hc, ce);
+      hc->cache_size -= vec_len (ce->data);
+      hc->cache_evictions++;
+      vec_free (ce->filename);
+      vec_free (ce->data);
+      if (hc->debug_level > 1)
+	clib_warning ("pool put index %d", ce - hc->cache_pool);
+      pool_put (hc->cache_pool, ce);
+      free_index = hc->last_index;
+    }
+
+  hss_cache_unlock (hc);
+
+  return busy_items;
+}
+
+void
+hss_cache_init (hss_cache_t *hc, uword cache_size, u8 debug_level)
+{
+  clib_spinlock_init (&hc->cache_lock);
+
+  /* Init path-to-cache hash table */
+  BV (clib_bihash_init) (&hc->name_to_data, "http cache", 128, 32 << 20);
+
+  hc->cache_limit = cache_size;
+  hc->debug_level = debug_level;
+  hc->first_index = hc->last_index = ~0;
+}
+
+/** \brief format a file cache entry
+ */
+static u8 *
+format_hss_cache_entry (u8 *s, va_list *args)
+{
+  hss_cache_entry_t *ep = va_arg (*args, hss_cache_entry_t *);
+  f64 now = va_arg (*args, f64);
+
+  /* Header */
+  if (ep == 0)
+    {
+      s = format (s, "%40s%12s%20s", "File", "Size", "Age");
+      return s;
+    }
+  s = format (s, "%40s%12lld%20.2f", ep->filename, vec_len (ep->data),
+	      now - ep->last_used);
+  return s;
+}
+
+u8 *
+format_hss_cache (u8 *s, va_list *args)
+{
+  hss_cache_t *hc = va_arg (*args, hss_cache_t *);
+  u32 verbose = va_arg (*args, u32);
+  hss_cache_entry_t *ce;
+  vlib_main_t *vm;
+  u32 index;
+  f64 now;
+
+  if (verbose == 0)
+    {
+      s = format (s, "cache size %lld bytes, limit %lld bytes, evictions %lld",
+		  hc->cache_size, hc->cache_limit, hc->cache_evictions);
+      return 0;
+    }
+
+  vm = vlib_get_main ();
+  now = vlib_time_now (vm);
+
+  s = format (s, "%U", format_hss_cache_entry, 0 /* header */, now);
+
+  for (index = hc->first_index; index != ~0;)
+    {
+      ce = pool_elt_at_index (hc->cache_pool, index);
+      index = ce->next_index;
+      s = format (s, "%U", format_hss_cache_entry, ce, now);
+    }
+
+  s = format (s, "%40s%12lld", "Total Size", hc->cache_size);
+
+  return s;
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */