Static http server

Good enough to serve the vpp sphinx and doxygen docs. Knows about
html, css, and javascript files.

Change-Id: Ib18c19f07f35f91ba935ea26ed7be406dacf2205
Signed-off-by: Dave Barach <dave@barachs.net>

1 files changed, 1392 insertions, 0 deletions

diff --git a/src/plugins/http_static/static_server.c b/src/plugins/http_static/static_server.c
new file mode 100644
index 00000000000..970db0d6798
--- /dev/null
+++ b/src/plugins/http_static/static_server.c
@@ -0,0 +1,1392 @@
+/*
+ * Copyright (c) 2017-2019 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 <vnet/vnet.h>
+#include <vnet/session/application.h>
+#include <vnet/session/application_interface.h>
+#include <vnet/session/session.h>
+#include <vppinfra/tw_timer_2t_1w_2048sl.h>
+#include <vppinfra/unix.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <http_static/http_static.h>
+#include <vppinfra/bihash_vec8_8.h>
+
+#include <vppinfra/bihash_template.c>
+
+/** @file
+    Simple Static http server, sufficient to
+    serve .html / .css / .js content.
+*/
+/*? %%clicmd:group_label Static HTTP Server %% ?*/
+
+/** \brief Session States
+ */
+
+typedef enum
+{
+  /** Session is closed */
+  HTTP_STATE_CLOSED,
+  /** Session is established */
+  HTTP_STATE_ESTABLISHED,
+  /** Session has sent an OK response */
+  HTTP_STATE_OK_SENT,
+  /** Session has sent an HTML response */
+  HTTP_STATE_RESPONSE_SENT,
+} http_session_state_t;
+
+/** \brief Application session
+ */
+typedef struct
+{
+  CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
+  /** Base class instance variables */
+#define _(type, name) type name;
+  foreach_app_session_field
+#undef _
+  /** rx thread index */
+  u32 thread_index;
+  /** rx buffer */
+  u8 *rx_buf;
+  /** vpp session index, handle */
+  u32 vpp_session_index;
+  u64 vpp_session_handle;
+  /** Timeout timer handle */
+  u32 timer_handle;
+  /** Fully-resolved file path */
+  u8 *path;
+  /** File data, a vector */
+  u8 *data;
+  /** Current data send offset */
+  u32 data_offset;
+  /** File cache pool index */
+  u32 cache_pool_index;
+} http_session_t;
+
+/** \brief In-memory file data cache entry
+ */
+typedef struct
+{
+  /** Name of the file */
+  u8 *filename;
+  /** Contents of the file, as a u8 * vector */
+  u8 *data;
+  /** Last time the cache entry was used */
+  f64 last_used;
+  /** Cache LRU links */
+  u32 next_index;
+  u32 prev_index;
+  /** Reference count, so we don't recycle while referenced */
+  int inuse;
+} file_data_cache_t;
+
+/** \brief Main data structure
+ */
+
+typedef struct
+{
+  /** Per thread vector of session pools */
+  http_session_t **sessions;
+  /** Session pool reader writer lock */
+  clib_rwlock_t sessions_lock;
+  /** vpp session to http session index map */
+  u32 **session_to_http_session;
+
+  /** vpp message/event queue */
+  svm_msg_q_t **vpp_queue;
+
+  /** Unified file data cache pool */
+  file_data_cache_t *cache_pool;
+  /** Hash table which maps file name to file data */
+    BVT (clib_bihash) name_to_data;
+
+  /** Current cache size */
+  u64 cache_size;
+  /** Max cache size in bytes */
+  u64 cache_limit;
+  /** Number of cache evictions */
+  u64 cache_evictions;
+
+  /** Cache LRU listheads */
+  u32 first_index;
+  u32 last_index;
+
+  /** root path to be served */
+  u8 *www_root;
+
+  /** Server's event queue */
+  svm_queue_t *vl_input_queue;
+
+  /** API client handle */
+  u32 my_client_index;
+
+  /** Application index */
+  u32 app_index;
+
+  /** Process node index for event scheduling */
+  u32 node_index;
+
+  /** Session cleanup timer wheel */
+  tw_timer_wheel_2t_1w_2048sl_t tw;
+  clib_spinlock_t tw_lock;
+
+  /** Time base, so we can generate browser cache control http spew */
+  clib_timebase_t timebase;
+
+  /** Number of preallocated fifos, usually 0 */
+  u32 prealloc_fifos;
+  /** Private segment size, usually 0 */
+  u32 private_segment_size;
+  /** Size of the allocated rx, tx fifos, roughly 8K or so */
+  u32 fifo_size;
+  /** The bind URI, defaults to tcp://0.0.0.0/80 */
+  u8 *uri;
+  vlib_main_t *vlib_main;
+} http_static_server_main_t;
+
+http_static_server_main_t http_static_server_main;
+
+/** \brief Acquire reader lock on the sessions pools
+ */
+static void
+http_static_server_sessions_reader_lock (void)
+{
+  clib_rwlock_reader_lock (&http_static_server_main.sessions_lock);
+}
+
+/** \brief Drop reader lock on the sessions pools
+ */
+static void
+http_static_server_sessions_reader_unlock (void)
+{
+  clib_rwlock_reader_unlock (&http_static_server_main.sessions_lock);
+}
+
+/** \brief Acquire writer lock on the sessions pools
+ */
+static void
+http_static_server_sessions_writer_lock (void)
+{
+  clib_rwlock_writer_lock (&http_static_server_main.sessions_lock);
+}
+
+/** \brief Drop writer lock on the sessions pools
+ */
+static void
+http_static_server_sessions_writer_unlock (void)
+{
+  clib_rwlock_writer_unlock (&http_static_server_main.sessions_lock);
+}
+
+/** \brief Allocate an http session
+ */
+static http_session_t *
+http_static_server_session_alloc (u32 thread_index)
+{
+  http_static_server_main_t *hsm = &http_static_server_main;
+  http_session_t *hs;
+  pool_get (hsm->sessions[thread_index], hs);
+  memset (hs, 0, sizeof (*hs));
+  hs->session_index = hs - hsm->sessions[thread_index];
+  hs->thread_index = thread_index;
+  hs->timer_handle = ~0;
+  hs->cache_pool_index = ~0;
+  return hs;
+}
+
+/** \brief Get an http session by index
+ */
+static http_session_t *
+http_static_server_session_get (u32 thread_index, u32 hs_index)
+{
+  http_static_server_main_t *hsm = &http_static_server_main;
+  if (pool_is_free_index (hsm->sessions[thread_index], hs_index))
+    return 0;
+  return pool_elt_at_index (hsm->sessions[thread_index], hs_index);
+}
+
+/** \brief Free an http session
+ */
+static void
+http_static_server_session_free (http_session_t * hs)
+{
+  http_static_server_main_t *hsm = &http_static_server_main;
+  pool_put (hsm->sessions[hs->thread_index], hs);
+  if (CLIB_DEBUG)
+    memset (hs, 0xfa, sizeof (*hs));
+}
+
+/** \brief add a session to the vpp < -- > http session index map
+ */
+static void
+http_static_server_session_lookup_add (u32 thread_index, u32 s_index,
+				       u32 hs_index)
+{
+  http_static_server_main_t *hsm = &http_static_server_main;
+  vec_validate (hsm->session_to_http_session[thread_index], s_index);
+  hsm->session_to_http_session[thread_index][s_index] = hs_index;
+}
+
+/** \brief Remove a session from the vpp < -- > http session index map
+ */
+static void
+http_static_server_session_lookup_del (u32 thread_index, u32 s_index)
+{
+  http_static_server_main_t *hsm = &http_static_server_main;
+  hsm->session_to_http_session[thread_index][s_index] = ~0;
+}
+
+/** \brief lookup a session in the vpp < -- > http session index map
+ */
+
+static http_session_t *
+http_static_server_session_lookup (u32 thread_index, u32 s_index)
+{
+  http_static_server_main_t *hsm = &http_static_server_main;
+  u32 hs_index;
+
+  if (s_index < vec_len (hsm->session_to_http_session[thread_index]))
+    {
+      hs_index = hsm->session_to_http_session[thread_index][s_index];
+      return http_static_server_session_get (thread_index, hs_index);
+    }
+  return 0;
+}
+
+/** \brief Start a session cleanup timer
+ */
+
+static void
+http_static_server_session_timer_start (http_session_t * hs)
+{
+  u32 hs_handle;
+  hs_handle = hs->thread_index << 24 | hs->session_index;
+  clib_spinlock_lock (&http_static_server_main.tw_lock);
+  hs->timer_handle = tw_timer_start_2t_1w_2048sl (&http_static_server_main.tw,
+						  hs_handle, 0, 60);
+  clib_spinlock_unlock (&http_static_server_main.tw_lock);
+}
+
+/** \brief stop a session cleanup timer
+ */
+static void
+http_static_server_session_timer_stop (http_session_t * hs)
+{
+  if (hs->timer_handle == ~0)
+    return;
+  clib_spinlock_lock (&http_static_server_main.tw_lock);
+  tw_timer_stop_2t_1w_2048sl (&http_static_server_main.tw, hs->timer_handle);
+  clib_spinlock_unlock (&http_static_server_main.tw_lock);
+}
+
+/** \brief Clean up an http session
+ */
+
+static void
+http_static_server_session_cleanup (http_session_t * hs)
+{
+  http_static_server_main_t *hsm = &http_static_server_main;
+  file_data_cache_t *ep;
+
+  if (!hs)
+    return;
+
+  /*
+   * Decrement cache pool entry reference count
+   * Note that if e.g. a file lookup fails, the cache pool index
+   * won't be set
+   */
+  if (hs->cache_pool_index != ~0)
+    {
+      ep = pool_elt_at_index (hsm->cache_pool, hs->cache_pool_index);
+      ep->inuse--;
+      if (0)
+	clib_warning ("index %d refcnt now %d", hs->cache_pool_index,
+		      ep->inuse);
+    }
+
+  http_static_server_session_lookup_del (hs->thread_index,
+					 hs->vpp_session_index);
+  vec_free (hs->rx_buf);
+  vec_free (hs->path);
+  http_static_server_session_timer_stop (hs);
+  http_static_server_session_free (hs);
+}
+
+/** \brief Disconnect a session
+ */
+
+static void
+http_static_server_session_disconnect (http_session_t * hs)
+{
+  vnet_disconnect_args_t _a = { 0 }, *a = &_a;
+  a->handle = hs->vpp_session_handle;
+  a->app_index = http_static_server_main.app_index;
+  vnet_disconnect_session (a);
+}
+
+/* *INDENT-OFF* */
+/** \brief http error boilerplate
+ */
+static const char *http_error_template =
+    "HTTP/1.1 %s\r\n"
+    "Date: %U GMT\r\n"
+    "Content-Type: text/html\r\n"
+    "Connection: close\r\n"
+    "Pragma: no-cache\r\n"
+    "Content-Length: 0\r\n\r\n";
+
+/** \brief http response boilerplate
+ */
+static const char *http_response_template =
+    "Date: %U GMT\r\n"
+    "Expires: %U GMT\r\n"
+    "Server: VPP Static\r\n"
+    "Content-Type: text/%s\r\n"
+    "Connection: close \r\n"
+    "Content-Length: %d\r\n\r\n";
+
+/* *INDENT-ON* */
+
+/** \brief send http data
+    @param hs - http session
+    @param data - the data vector to transmit
+    @param offset - transmit offset for this operation
+    @return offset for next transmit operation, may be unchanged w/ full fifo
+*/
+
+static u32
+static_send_data (http_session_t * hs, u8 * data, u32 length, u32 offset)
+{
+  u32 bytes_to_send;
+
+  bytes_to_send = length - offset;
+
+  while (bytes_to_send > 0)
+    {
+      int actual_transfer;
+
+      actual_transfer = svm_fifo_enqueue_nowait
+	(hs->tx_fifo, bytes_to_send, data + offset);
+
+      /* Made any progress? */
+      if (actual_transfer <= 0)
+	return offset;
+      else
+	{
+	  offset += actual_transfer;
+	  bytes_to_send -= actual_transfer;
+
+	  if (svm_fifo_set_event (hs->tx_fifo))
+	    session_send_io_evt_to_thread (hs->tx_fifo,
+					   SESSION_IO_EVT_TX_FLUSH);
+	  return offset;
+	}
+    }
+  /* NOTREACHED */
+  return ~0;
+}
+
+/** \brief Send an http error string
+    @param hs - the http session
+    @param str - the error string, e.g. "404 Not Found"
+*/
+static void
+send_error (http_session_t * hs, char *str)
+{
+  http_static_server_main_t *hsm = &http_static_server_main;
+  u8 *data;
+  f64 now;
+
+  now = clib_timebase_now (&hsm->timebase);
+  data = format (0, http_error_template, str, format_clib_timebase_time, now);
+  static_send_data (hs, data, vec_len (data), 0);
+  vec_free (data);
+}
+
+/** \brief Retrieve data from the application layer
+ */
+static int
+session_rx_request (http_session_t * hs)
+{
+  u32 max_dequeue, cursize;
+  int n_read;
+
+  cursize = vec_len (hs->rx_buf);
+  max_dequeue = svm_fifo_max_dequeue (hs->rx_fifo);
+  if (PREDICT_FALSE (max_dequeue == 0))
+    return -1;
+
+  vec_validate (hs->rx_buf, cursize + max_dequeue - 1);
+  n_read = app_recv_stream_raw (hs->rx_fifo, hs->rx_buf + cursize,
+				max_dequeue, 0, 0 /* peek */ );
+  ASSERT (n_read == max_dequeue);
+  if (svm_fifo_is_empty (hs->rx_fifo))
+    svm_fifo_unset_event (hs->rx_fifo);
+
+  _vec_len (hs->rx_buf) = cursize + n_read;
+  return 0;
+}
+
+/** \brief Sanity-check the forward and reverse LRU lists
+ */
+static inline void
+lru_validate (http_static_server_main_t * hsm)
+{
+#if CLIB_DEBUG > 0
+  f64 last_timestamp;
+  u32 index;
+  int i;
+  file_data_cache_t *ep;
+
+  last_timestamp = 1e70;
+  for (i = 1, index = hsm->first_index; index != ~0;)
+    {
+      ep = pool_elt_at_index (hsm->cache_pool, index);
+      index = ep->next_index;
+      /* Timestamps should be smaller (older) as we walk the fwd list */
+      if (ep->last_used > last_timestamp)
+	{
+	  clib_warning ("%d[%d]: last used %.6f, last_timestamp %.6f",
+			ep - hsm->cache_pool, i,
+			ep->last_used, last_timestamp);
+	}
+      last_timestamp = ep->last_used;
+      i++;
+    }
+
+  last_timestamp = 0.0;
+  for (i = 1, index = hsm->last_index; index != ~0;)
+    {
+      ep = pool_elt_at_index (hsm->cache_pool, index);
+      index = ep->prev_index;
+      /* Timestamps should be larger (newer) as we walk the rev list */
+      if (ep->last_used < last_timestamp)
+	{
+	  clib_warning ("%d[%d]: last used %.6f, last_timestamp %.6f",
+			ep - hsm->cache_pool, i,
+			ep->last_used, last_timestamp);
+	}
+      last_timestamp = ep->last_used;
+      i++;
+    }
+#endif
+}
+
+/** \brief Remove a data cache entry from the LRU lists
+ */
+static inline void
+lru_remove (http_static_server_main_t * hsm, file_data_cache_t * ep)
+{
+  file_data_cache_t *next_ep, *prev_ep;
+  u32 ep_index;
+
+  lru_validate (hsm);
+
+  ep_index = ep - hsm->cache_pool;
+
+  /* Deal with list heads */
+  if (ep_index == hsm->first_index)
+    hsm->first_index = ep->next_index;
+  if (ep_index == hsm->last_index)
+    hsm->last_index = ep->prev_index;
+
+  /* Fix next->prev */
+  if (ep->next_index != ~0)
+    {
+      next_ep = pool_elt_at_index (hsm->cache_pool, ep->next_index);
+      next_ep->prev_index = ep->prev_index;
+    }
+  /* Fix prev->next */
+  if (ep->prev_index != ~0)
+    {
+      prev_ep = pool_elt_at_index (hsm->cache_pool, ep->prev_index);
+      prev_ep->next_index = ep->next_index;
+    }
+  lru_validate (hsm);
+}
+
+/** \brief Add an entry to the LRU lists, tag w/ supplied timestamp
+ */
+
+static inline void
+lru_add (http_static_server_main_t * hsm, file_data_cache_t * ep, f64 now)
+{
+  file_data_cache_t *next_ep;
+  u32 ep_index;
+
+  lru_validate (hsm);
+
+  ep_index = ep - hsm->cache_pool;
+
+  /*
+   * Re-add at the head of the forward LRU list,
+   * tail of the reverse LRU list
+   */
+  if (hsm->first_index != ~0)
+    {
+      next_ep = pool_elt_at_index (hsm->cache_pool, hsm->first_index);
+      next_ep->prev_index = ep_index;
+    }
+
+  ep->prev_index = ~0;
+
+  /* ep now the new head of the LRU forward list */
+  ep->next_index = hsm->first_index;
+  hsm->first_index = ep_index;
+
+  /* single session case: also the tail of the reverse LRU list */
+  if (hsm->last_index == ~0)
+    hsm->last_index = ep_index;
+  ep->last_used = now;
+
+  lru_validate (hsm);
+}
+
+/** \brief Remove and re-add a cache entry from/to the LRU lists
+ */
+
+static inline void
+lru_update (http_static_server_main_t * hsm, file_data_cache_t * ep, f64 now)
+{
+  lru_remove (hsm, ep);
+  lru_add (hsm, ep, now);
+}
+
+/** \brief Session-layer (main) data rx callback.
+    Parse the http request, and reply to it.
+    Future extensions might include POST processing, active content, etc.
+*/
+
+static int
+http_static_server_rx_callback (session_t * s)
+{
+  http_static_server_main_t *hsm = &http_static_server_main;
+  u32 request_len;
+  u8 *request = 0;
+  u8 *path;
+  http_session_t *hs;
+  int i, rv;
+  struct stat _sb, *sb = &_sb;
+  u8 *http_response;
+  f64 now;
+  clib_error_t *error;
+  char *suffix;
+  char *http_type;
+
+  /* Acquire a reader lock on the session table */
+  http_static_server_sessions_reader_lock ();
+  hs = http_static_server_session_lookup (s->thread_index, s->session_index);
+
+  /* No such session? Say goodnight, Gracie... */
+  if (!hs || hs->session_state == HTTP_STATE_CLOSED)
+    {
+      http_static_server_sessions_reader_unlock ();
+      return 0;
+    }
+
+  /* If this session has already sent "OK 200" */
+  if (hs->session_state == HTTP_STATE_OK_SENT)
+    goto static_send_response;
+
+  /* If this session has already sent a response (needs to send more data)  */
+  if (hs->session_state == HTTP_STATE_RESPONSE_SENT)
+    goto static_send_data;
+
+  /* Read data from the sesison layer */
+  rv = session_rx_request (hs);
+  if (rv)
+    goto wait_for_data;
+
+  /* Process the client request */
+  request = hs->rx_buf;
+  request_len = vec_len (request);
+  if (vec_len (request) < 7)
+    {
+      send_error (hs, "400 Bad Request");
+      goto close_session;
+    }
+
+  /* We only handle GET requests at the moment */
+  for (i = 0; i < request_len - 4; i++)
+    {
+      if (request[i] == 'G' &&
+	  request[i + 1] == 'E' &&
+	  request[i + 2] == 'T' && request[i + 3] == ' ')
+	goto find_end;
+    }
+  send_error (hs, "400 Bad Request");
+  goto close_session;
+
+find_end:
+
+  /* Lose "GET " */
+  vec_delete (request, i + 5, 0);
+
+  /* Lose stuff to the right of the path */
+  for (i = 0; i < vec_len (request); i++)
+    {
+      if (request[i] == ' ' || request[i] == '?')
+	{
+	  request[i] = 0;
+	  break;
+	}
+    }
+
+  /* Now we can construc the file to open */
+  path = format (0, "%s/%s%c", hsm->www_root, request, 0);
+
+  if (0)
+    clib_warning ("GET '%s'", path);
+
+  /* Try to find the file. 2x special cases to find index.html */
+  if (stat ((char *) path, sb) < 0	/* cant even stat the file */
+      || sb->st_size < 20	/* file too small */
+      || (sb->st_mode & S_IFMT) != S_IFREG /* not a regular file */ )
+    {
+      u32 save_length = vec_len (path) - 1;
+      /* Try appending "index.html"... */
+      _vec_len (path) -= 1;
+      path = format (path, "index.html%c", 0);
+      if (stat ((char *) path, sb) < 0	/* cant even stat the file */
+	  || sb->st_size < 20	/* file too small */
+	  || (sb->st_mode & S_IFMT) != S_IFREG /* not a regular file */ )
+	{
+	  _vec_len (path) = save_length;
+	  path = format (path, "/index.html%c", 0);
+
+	  /* Send a redirect, otherwise the browser will confuse itself */
+	  if (stat ((char *) path, sb) < 0	/* cant even stat the file */
+	      || sb->st_size < 20	/* file too small */
+	      || (sb->st_mode & S_IFMT) != S_IFREG /* not a regular file */ )
+	    {
+	      vec_free (path);
+	      send_error (hs, "404 Not Found");
+	      goto close_session;
+	    }
+	  else
+	    {
+	      transport_connection_t *tc;
+	      /*
+	       * To make this bit work correctly, we need to know our local
+	       * IP address, etc. and send it in the redirect...
+	       */
+	      u8 *redirect;
+
+	      vec_delete (path, vec_len (hsm->www_root) - 1, 0);
+
+	      if (0)
+		clib_warning ("redirect to '%s'", path);
+
+	      tc = session_get_transport (s);
+	      redirect = format (0, "HTTP/1.1 301 Moved Permanently\r\n"
+				 "Location: http://%U/%s",
+				 format_ip46_address, &tc->lcl_ip, tc->is_ip4,
+				 path);
+	      static_send_data (hs, redirect, vec_len (redirect), 0);
+	      vec_free (path);
+	      vec_free (redirect);
+	      goto close_session;
+	    }
+	}
+    }
+
+  hs->path = path;
+  /* send 200 OK first */
+
+  static_send_data (hs, (u8 *) "HTTP/1.1 200 OK\r\n", 17, 0);
+  hs->session_state = HTTP_STATE_OK_SENT;
+  goto postpone;
+
+static_send_response:
+
+  ASSERT (hs->path);
+
+  /* find or read the file if we haven't done so yet. */
+  if (hs->data == 0)
+    {
+      BVT (clib_bihash_kv) kv;
+      file_data_cache_t *dp;
+
+      /* First, try the cache */
+      kv.key = (u64) hs->path;
+      if (BV (clib_bihash_search) (&hsm->name_to_data, &kv, &kv) == 0)
+	{
+	  /* found the data.. */
+	  dp = pool_elt_at_index (hsm->cache_pool, kv.value);
+	  hs->data = dp->data;
+	  /* Update the cache entry, mark it in-use */
+	  lru_update (hsm, dp, vlib_time_now (hsm->vlib_main));
+	  hs->cache_pool_index = dp - hsm->cache_pool;
+	  dp->inuse++;
+	  if (0)
+	    clib_warning ("index %d refcnt now %d", hs->cache_pool_index,
+			  dp->inuse);
+	}
+      else
+	{
+	  /* Need to recycle one (or more cache) entries? */
+	  if (hsm->cache_size > hsm->cache_limit)
+	    {
+	      int free_index = hsm->last_index;
+
+	      while (free_index != ~0)
+		{
+		  /* pick the LRU */
+		  dp = pool_elt_at_index (hsm->cache_pool, free_index);
+		  free_index = dp->prev_index;
+		  /* Which could be in use... */
+		  if (dp->inuse)
+		    {
+		      if (0)
+			clib_warning ("index %d in use refcnt %d",
+				      dp - hsm->cache_pool, dp->inuse);
+		      continue;
+		    }
+
+		  BV (clib_bihash_add_del) (&hsm->name_to_data, &kv,
+					    0 /* is_add */ );
+		  lru_remove (hsm, dp);
+		  hsm->cache_size -= vec_len (dp->data);
+		  hsm->cache_evictions++;
+		  vec_free (dp->filename);
+		  vec_free (dp->data);
+		  pool_put (hsm->cache_pool, dp);
+		  if (hsm->cache_size < hsm->cache_limit)
+		    break;
+		}
+	    }
+
+	  /* Read the file */
+	  error = clib_file_contents ((char *) (hs->path), &hs->data);
+	  if (error)
+	    {
+	      clib_warning ("Error reading '%s'", hs->path);
+	      clib_error_report (error);
+	      vec_free (hs->path);
+	      goto close_session;
+	    }
+	  /* Create a cache entry for it */
+	  pool_get (hsm->cache_pool, dp);
+	  memset (dp, 0, sizeof (*dp));
+	  dp->filename = vec_dup (hs->path);
+	  dp->data = hs->data;
+	  hs->cache_pool_index = dp - hsm->cache_pool;
+	  dp->inuse++;
+	  if (0)
+	    clib_warning ("index %d refcnt now %d", hs->cache_pool_index,
+			  dp->inuse);
+	  lru_add (hsm, dp, vlib_time_now (hsm->vlib_main));
+	  kv.key = (u64) vec_dup (hs->path);
+	  kv.value = dp - hsm->cache_pool;
+	  /* Add to the lookup table */
+	  BV (clib_bihash_add_del) (&hsm->name_to_data, &kv, 1 /* is_add */ );
+	  hsm->cache_size += vec_len (dp->data);
+	}
+      hs->data_offset = 0;
+    }
+
+  /* What kind of dog food are we serving? */
+  suffix = (char *) (hs->path + vec_len (hs->path) - 1);
+  while (*suffix != '.')
+    suffix--;
+  suffix++;
+  http_type = "html";
+  if (!clib_strcmp (suffix, "css"))
+    http_type = "css";
+  else if (!clib_strcmp (suffix, "js"))
+    http_type = "javascript";
+
+  /*
+   * Send an http response, which needs the current time,
+   * the expiration time, and the data length
+   */
+  now = clib_timebase_now (&hsm->timebase);
+  http_response = format (0, http_response_template,
+			  /* Date */
+			  format_clib_timebase_time, now,
+			  /* Expires */
+			  format_clib_timebase_time, now + 600.0,
+			  http_type, vec_len (hs->data));
+  static_send_data (hs, http_response, vec_len (http_response), 0);
+  vec_free (http_response);
+  hs->session_state = HTTP_STATE_RESPONSE_SENT;
+  /* NOTE FALLTHROUGH */
+
+static_send_data:
+
+  /*
+   * Try to send data. Ideally, the fifos will be large
+   * enough to send the entire file in one motion.
+   */
+
+  hs->data_offset = static_send_data (hs, hs->data, vec_len (hs->data),
+				      hs->data_offset);
+  if (hs->data_offset < vec_len (hs->data))
+    goto postpone;
+
+close_session:
+  http_static_server_session_disconnect (hs);
+  http_static_server_session_cleanup (hs);
+  http_static_server_sessions_reader_unlock ();
+  return 0;
+
+postpone:
+  (void) svm_fifo_set_event (hs->rx_fifo);
+  session_send_io_evt_to_thread (hs->rx_fifo, SESSION_IO_EVT_BUILTIN_RX);
+  http_static_server_sessions_reader_unlock ();
+  return 0;
+
+wait_for_data:
+  http_static_server_sessions_reader_unlock ();
+  return 0;
+}
+
+/** \brief Session accept callback
+ */
+
+static int
+http_static_server_session_accept_callback (session_t * s)
+{
+  http_static_server_main_t *hsm = &http_static_server_main;
+  http_session_t *hs;
+
+  hsm->vpp_queue[s->thread_index] =
+    session_main_get_vpp_event_queue (s->thread_index);
+
+  http_static_server_sessions_writer_lock ();
+
+  hs = http_static_server_session_alloc (s->thread_index);
+  http_static_server_session_lookup_add (s->thread_index, s->session_index,
+					 hs->session_index);
+  hs->rx_fifo = s->rx_fifo;
+  hs->tx_fifo = s->tx_fifo;
+  hs->vpp_session_index = s->session_index;
+  hs->vpp_session_handle = session_handle (s);
+  hs->session_state = HTTP_STATE_ESTABLISHED;
+  http_static_server_session_timer_start (hs);
+
+  http_static_server_sessions_writer_unlock ();
+
+  s->session_state = SESSION_STATE_READY;
+  return 0;
+}
+
+/** \brief Session disconnect callback
+ */
+
+static void
+http_static_server_session_disconnect_callback (session_t * s)
+{
+  http_static_server_main_t *hsm = &http_static_server_main;
+  vnet_disconnect_args_t _a = { 0 }, *a = &_a;
+  http_session_t *hs;
+
+  http_static_server_sessions_writer_lock ();
+
+  hs = http_static_server_session_lookup (s->thread_index, s->session_index);
+  http_static_server_session_cleanup (hs);
+
+  http_static_server_sessions_writer_unlock ();
+
+  a->handle = session_handle (s);
+  a->app_index = hsm->app_index;
+  vnet_disconnect_session (a);
+}
+
+/** \brief Session reset callback
+ */
+
+static void
+http_static_server_session_reset_callback (session_t * s)
+{
+  http_static_server_main_t *hsm = &http_static_server_main;
+  vnet_disconnect_args_t _a = { 0 }, *a = &_a;
+  http_session_t *hs;
+
+  http_static_server_sessions_writer_lock ();
+
+  hs = http_static_server_session_lookup (s->thread_index, s->session_index);
+  http_static_server_session_cleanup (hs);
+
+  http_static_server_sessions_writer_unlock ();
+
+  a->handle = session_handle (s);
+  a->app_index = hsm->app_index;
+  vnet_disconnect_session (a);
+}
+
+static int
+http_static_server_session_connected_callback (u32 app_index, u32 api_context,
+					       session_t * s, u8 is_fail)
+{
+  clib_warning ("called...");
+  return -1;
+}
+
+static int
+http_static_server_add_segment_callback (u32 client_index, u64 segment_handle)
+{
+  clib_warning ("called...");
+  return -1;
+}
+
+/** \brief Session-layer virtual function table
+ */
+static session_cb_vft_t http_static_server_session_cb_vft = {
+  .session_accept_callback = http_static_server_session_accept_callback,
+  .session_disconnect_callback =
+    http_static_server_session_disconnect_callback,
+  .session_connected_callback = http_static_server_session_connected_callback,
+  .add_segment_callback = http_static_server_add_segment_callback,
+  .builtin_app_rx_callback = http_static_server_rx_callback,
+  .session_reset_callback = http_static_server_session_reset_callback
+};
+
+static int
+http_static_server_attach ()
+{
+  vnet_app_add_tls_cert_args_t _a_cert, *a_cert = &_a_cert;
+  vnet_app_add_tls_key_args_t _a_key, *a_key = &_a_key;
+  http_static_server_main_t *hsm = &http_static_server_main;
+  u64 options[APP_OPTIONS_N_OPTIONS];
+  vnet_app_attach_args_t _a, *a = &_a;
+  u32 segment_size = 128 << 20;
+
+  clib_memset (a, 0, sizeof (*a));
+  clib_memset (options, 0, sizeof (options));
+
+  if (hsm->private_segment_size)
+    segment_size = hsm->private_segment_size;
+
+  a->api_client_index = ~0;
+  a->name = format (0, "test_http_static_server");
+  a->session_cb_vft = &http_static_server_session_cb_vft;
+  a->options = options;
+  a->options[APP_OPTIONS_SEGMENT_SIZE] = segment_size;
+  a->options[APP_OPTIONS_RX_FIFO_SIZE] =
+    hsm->fifo_size ? hsm->fifo_size : 8 << 10;
+  a->options[APP_OPTIONS_TX_FIFO_SIZE] =
+    hsm->fifo_size ? hsm->fifo_size : 32 << 10;
+  a->options[APP_OPTIONS_FLAGS] = APP_OPTIONS_FLAGS_IS_BUILTIN;
+  a->options[APP_OPTIONS_PREALLOC_FIFO_PAIRS] = hsm->prealloc_fifos;
+
+  if (vnet_application_attach (a))
+    {
+      vec_free (a->name);
+      clib_warning ("failed to attach server");
+      return -1;
+    }
+  vec_free (a->name);
+  hsm->app_index = a->app_index;
+
+  clib_memset (a_cert, 0, sizeof (*a_cert));
+  a_cert->app_index = a->app_index;
+  vec_validate (a_cert->cert, test_srv_crt_rsa_len);
+  clib_memcpy_fast (a_cert->cert, test_srv_crt_rsa, test_srv_crt_rsa_len);
+  vnet_app_add_tls_cert (a_cert);
+
+  clib_memset (a_key, 0, sizeof (*a_key));
+  a_key->app_index = a->app_index;
+  vec_validate (a_key->key, test_srv_key_rsa_len);
+  clib_memcpy_fast (a_key->key, test_srv_key_rsa, test_srv_key_rsa_len);
+  vnet_app_add_tls_key (a_key);
+
+  return 0;
+}
+
+static int
+http_static_server_listen ()
+{
+  http_static_server_main_t *hsm = &http_static_server_main;
+  vnet_listen_args_t _a, *a = &_a;
+  clib_memset (a, 0, sizeof (*a));
+  a->app_index = hsm->app_index;
+  a->uri = "tcp://0.0.0.0/80";
+  if (hsm->uri)
+    a->uri = (char *) hsm->uri;
+  return vnet_bind_uri (a);
+}
+
+static void
+http_static_server_session_cleanup_cb (void *hs_handlep)
+{
+  http_session_t *hs;
+  uword hs_handle;
+  hs_handle = pointer_to_uword (hs_handlep);
+  hs =
+    http_static_server_session_get (hs_handle >> 24, hs_handle & 0x00FFFFFF);
+  if (!hs)
+    return;
+  hs->timer_handle = ~0;
+  http_static_server_session_disconnect (hs);
+  http_static_server_session_cleanup (hs);
+}
+
+/** \brief Expired session timer-wheel callback
+ */
+static void
+http_expired_timers_dispatch (u32 * expired_timers)
+{
+  u32 hs_handle;
+  int i;
+
+  for (i = 0; i < vec_len (expired_timers); i++)
+    {
+      /* Get session handle. The first bit is the timer id */
+      hs_handle = expired_timers[i] & 0x7FFFFFFF;
+      session_send_rpc_evt_to_thread (hs_handle >> 24,
+				      http_static_server_session_cleanup_cb,
+				      uword_to_pointer (hs_handle, void *));
+    }
+}
+
+/** \brief Timer-wheel expiration process
+ */
+static uword
+http_static_server_process (vlib_main_t * vm, vlib_node_runtime_t * rt,
+			    vlib_frame_t * f)
+{
+  http_static_server_main_t *hsm = &http_static_server_main;
+  f64 now, timeout = 1.0;
+  uword *event_data = 0;
+  uword __clib_unused event_type;
+
+  while (1)
+    {
+      vlib_process_wait_for_event_or_clock (vm, timeout);
+      now = vlib_time_now (vm);
+      event_type = vlib_process_get_events (vm, (uword **) & event_data);
+
+      /* expire timers */
+      clib_spinlock_lock (&http_static_server_main.tw_lock);
+      tw_timer_expire_timers_2t_1w_2048sl (&hsm->tw, now);
+      clib_spinlock_unlock (&http_static_server_main.tw_lock);
+
+      vec_reset_length (event_data);
+    }
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (http_static_server_process_node) =
+{
+  .function = http_static_server_process,
+  .type = VLIB_NODE_TYPE_PROCESS,
+  .name = "static-http-server-process",
+  .state = VLIB_NODE_STATE_DISABLED,
+};
+/* *INDENT-ON* */
+
+static int
+http_static_server_create (vlib_main_t * vm)
+{
+  vlib_thread_main_t *vtm = vlib_get_thread_main ();
+  http_static_server_main_t *hsm = &http_static_server_main;
+  u32 num_threads;
+  vlib_node_t *n;
+
+  num_threads = 1 /* main thread */  + vtm->n_threads;
+  vec_validate (hsm->vpp_queue, num_threads - 1);
+  vec_validate (hsm->sessions, num_threads - 1);
+  vec_validate (hsm->session_to_http_session, num_threads - 1);
+
+  clib_rwlock_init (&hsm->sessions_lock);
+  clib_spinlock_init (&hsm->tw_lock);
+
+  if (http_static_server_attach ())
+    {
+      clib_warning ("failed to attach server");
+      return -1;
+    }
+  if (http_static_server_listen ())
+    {
+      clib_warning ("failed to start listening");
+      return -1;
+    }
+
+  /* Init path-to-cache hash table */
+  BV (clib_bihash_init) (&hsm->name_to_data, "http cache", 128, 32 << 20);
+
+  /* Init timer wheel and process */
+  tw_timer_wheel_init_2t_1w_2048sl (&hsm->tw, http_expired_timers_dispatch,
+				    1 /* timer interval */ , ~0);
+  vlib_node_set_state (vm, http_static_server_process_node.index,
+		       VLIB_NODE_STATE_POLLING);
+  n = vlib_get_node (vm, http_static_server_process_node.index);
+  vlib_start_process (vm, n->runtime_index);
+
+  return 0;
+}
+
+/** \brief API helper function for vl_api_http_static_enable_t messages
+ */
+int
+http_static_server_enable_api (u32 fifo_size, u32 cache_limit,
+			       u32 prealloc_fifos,
+			       u32 private_segment_size,
+			       u8 * www_root, u8 * uri)
+{
+  http_static_server_main_t *hsm = &http_static_server_main;
+  int rv;
+
+  hsm->fifo_size = fifo_size;
+  hsm->cache_limit = cache_limit;
+  hsm->prealloc_fifos = prealloc_fifos;
+  hsm->private_segment_size = private_segment_size;
+  hsm->www_root = format (0, "%s%c", www_root, 0);
+  hsm->uri = format (0, "%s%c", uri, 0);
+
+  if (vec_len (hsm->www_root) < 2)
+    return VNET_API_ERROR_INVALID_VALUE;
+
+  if (hsm->my_client_index != ~0)
+    return VNET_API_ERROR_APP_ALREADY_ATTACHED;
+
+  vnet_session_enable_disable (hsm->vlib_main, 1 /* turn on TCP, etc. */ );
+
+  rv = http_static_server_create (hsm->vlib_main);
+  switch (rv)
+    {
+    case 0:
+      break;
+    default:
+      vec_free (hsm->www_root);
+      vec_free (hsm->uri);
+      return VNET_API_ERROR_INIT_FAILED;
+    }
+  return 0;
+}
+
+static clib_error_t *
+http_static_server_create_command_fn (vlib_main_t * vm,
+				      unformat_input_t * input,
+				      vlib_cli_command_t * cmd)
+{
+  http_static_server_main_t *hsm = &http_static_server_main;
+  unformat_input_t _line_input, *line_input = &_line_input;
+  u64 seg_size;
+  u8 *www_root = 0;
+  int rv;
+
+  hsm->prealloc_fifos = 0;
+  hsm->private_segment_size = 0;
+  hsm->fifo_size = 0;
+  /* 10mb cache limit, before LRU occurs */
+  hsm->cache_limit = 10 << 20;
+
+  /* Get a line of input. */
+  if (!unformat_user (input, unformat_line_input, line_input))
+    goto no_wwwroot;
+
+  while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (line_input, "www-root %s", &www_root))
+	;
+      else
+	if (unformat (line_input, "prealloc-fifos %d", &hsm->prealloc_fifos))
+	;
+      else if (unformat (line_input, "private-segment-size %U",
+			 unformat_memory_size, &seg_size))
+	{
+	  if (seg_size >= 0x100000000ULL)
+	    {
+	      vlib_cli_output (vm, "private segment size %llu, too large",
+			       seg_size);
+	      return 0;
+	    }
+	  hsm->private_segment_size = seg_size;
+	}
+      else if (unformat (line_input, "fifo-size %d", &hsm->fifo_size))
+	hsm->fifo_size <<= 10;
+      else if (unformat (line_input, "cache-size %U", unformat_memory_size,
+			 &hsm->cache_limit))
+	{
+	  if (hsm->cache_limit < (128 << 10))
+	    {
+	      return clib_error_return (0,
+					"cache-size must be at least 128kb");
+	    }
+	}
+
+      else if (unformat (line_input, "uri %s", &hsm->uri))
+	;
+      else
+	return clib_error_return (0, "unknown input `%U'",
+				  format_unformat_error, line_input);
+    }
+  unformat_free (line_input);
+
+  if (www_root == 0)
+    {
+    no_wwwroot:
+      return clib_error_return (0, "Must specify www-root <path>");
+    }
+
+  if (hsm->my_client_index != (u32) ~ 0)
+    {
+      vec_free (www_root);
+      return clib_error_return (0, "http server already running...");
+    }
+
+  hsm->www_root = www_root;
+
+  vnet_session_enable_disable (vm, 1 /* turn on TCP, etc. */ );
+
+  rv = http_static_server_create (vm);
+  switch (rv)
+    {
+    case 0:
+      break;
+    default:
+      vec_free (hsm->www_root);
+      return clib_error_return (0, "server_create returned %d", rv);
+    }
+  return 0;
+}
+
+/*?
+ * Enable the static http server
+ *
+ * @cliexpar
+ * This command enables the static http server. Only the www-root
+ * parameter is required
+ * @clistart
+ * http static server www-root /tmp/www uri tcp://0.0.0.0/80 cache-size 2m
+ * @cliend
+ * @cliexcmd{http static server www-root <path> [prealloc-fios <nn>]
+ *   [private-segment-size <nnMG>] [fifo-size <nbytes>] [uri <uri>]}
+?*/
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (http_static_server_create_command, static) =
+{
+  .path = "http static server",
+  .short_help = "http static server www-root <path> [prealloc-fios <nn>]\n"
+  "[private-segment-size <nnMG>] [fifo-size <nbytes>] [uri <uri>]\n",
+  .function = http_static_server_create_command_fn,
+};
+/* *INDENT-ON* */
+
+/** \brief format a file cache entry
+ */
+u8 *
+format_hsm_cache_entry (u8 * s, va_list * args)
+{
+  file_data_cache_t *ep = va_arg (*args, file_data_cache_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;
+}
+
+static clib_error_t *
+http_show_static_server_command_fn (vlib_main_t * vm,
+				    unformat_input_t * input,
+				    vlib_cli_command_t * cmd)
+{
+  http_static_server_main_t *hsm = &http_static_server_main;
+  file_data_cache_t *ep, **entries = 0;
+  int verbose = 0;
+  u32 index;
+  f64 now;
+
+  if (hsm->www_root == 0)
+    return clib_error_return (0, "Static server disabled");
+
+  if (unformat (input, "verbose %d", &verbose))
+    ;
+  else if (unformat (input, "verbose"))
+    verbose = 1;
+
+  if (verbose == 0)
+    {
+      vlib_cli_output
+	(vm, "www_root %s, cache size %lld bytes, limit %lld bytes, "
+	 "evictions %lld",
+	 hsm->www_root, hsm->cache_size, hsm->cache_limit,
+	 hsm->cache_evictions);
+      return 0;
+    }
+
+  now = vlib_time_now (vm);
+
+  vlib_cli_output (vm, "%U", format_hsm_cache_entry, 0 /* header */ ,
+		   now);
+
+  for (index = hsm->first_index; index != ~0;)
+    {
+      ep = pool_elt_at_index (hsm->cache_pool, index);
+      index = ep->next_index;
+      vlib_cli_output (vm, "%U", format_hsm_cache_entry, ep, now);
+    }
+
+  vlib_cli_output (vm, "%40s%12lld", "Total Size", hsm->cache_size);
+
+  vec_free (entries);
+
+  return 0;
+}
+
+/*?
+ * Display static http server cache statistics
+ *
+ * @cliexpar
+ * This command shows the contents of the static http server cache
+ * @clistart
+ * show http static server
+ * @cliend
+ * @cliexcmd{show http static server [verbose]}
+?*/
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (http_show_static_server_command, static) =
+{
+  .path = "show http static server",
+  .short_help = "show http static server [verbose]",
+  .function = http_show_static_server_command_fn,
+};
+/* *INDENT-ON* */
+
+static clib_error_t *
+http_static_server_main_init (vlib_main_t * vm)
+{
+  http_static_server_main_t *hsm = &http_static_server_main;
+
+  hsm->my_client_index = ~0;
+  hsm->vlib_main = vm;
+  hsm->first_index = hsm->last_index = ~0;
+
+  clib_timebase_init (&hsm->timebase, 0 /* GMT */ ,
+		      CLIB_TIMEBASE_DAYLIGHT_NONE);
+
+  return 0;
+}
+
+VLIB_INIT_FUNCTION (http_static_server_main_init);
+
+/*
+* fd.io coding-style-patch-verification: ON
+*
+* Local Variables:
+* eval: (c-set-style "gnu")
+* End:
+*/