curl/lib/conncache.c

/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 2012 - 2016, Linus Nielsen Feltzing, <linus@haxx.se>
 * Copyright (C) 2012 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at https://curl.haxx.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ***************************************************************************/

#include "curl_setup.h"

#include <curl/curl.h>

#include "urldata.h"
#include "url.h"
#include "progress.h"
#include "multiif.h"
#include "sendf.h"
#include "conncache.h"
#include "share.h"
#include "sigpipe.h"
#include "connect.h"

/* The last 3 #include files should be in this order */
#include "curl_printf.h"
#include "curl_memory.h"
#include "memdebug.h"

#define CONN_LOCK(x) if((x)->share)                                     \
    Curl_share_lock((x), CURL_LOCK_DATA_CONNECT, CURL_LOCK_ACCESS_SINGLE)
#define CONN_UNLOCK(x) if((x)->share)                   \
    Curl_share_unlock((x), CURL_LOCK_DATA_CONNECT)


static void conn_llist_dtor(void *user, void *element)
{
  struct connectdata *data = element;
  (void)user;

  data->bundle = NULL;
}

static CURLcode bundle_create(struct Curl_easy *data,
                              struct connectbundle **cb_ptr)
{
  (void)data;
  DEBUGASSERT(*cb_ptr == NULL);
  *cb_ptr = malloc(sizeof(struct connectbundle));
  if(!*cb_ptr)
    return CURLE_OUT_OF_MEMORY;

  (*cb_ptr)->num_connections = 0;
  (*cb_ptr)->multiuse = BUNDLE_UNKNOWN;

  Curl_llist_init(&(*cb_ptr)->conn_list, (curl_llist_dtor) conn_llist_dtor);
  return CURLE_OK;
}

static void bundle_destroy(struct connectbundle *cb_ptr)
{
  if(!cb_ptr)
    return;

  Curl_llist_destroy(&cb_ptr->conn_list, NULL);

  free(cb_ptr);
}

/* Add a connection to a bundle */
static CURLcode bundle_add_conn(struct connectbundle *cb_ptr,
                                struct connectdata *conn)
{
  Curl_llist_insert_next(&cb_ptr->conn_list, cb_ptr->conn_list.tail, conn,
                         &conn->bundle_node);
  conn->bundle = cb_ptr;
  cb_ptr->num_connections++;
  return CURLE_OK;
}

/* Remove a connection from a bundle */
static int bundle_remove_conn(struct connectbundle *cb_ptr,
                              struct connectdata *conn)
{
  struct curl_llist_element *curr;

  curr = cb_ptr->conn_list.head;
  while(curr) {
    if(curr->ptr == conn) {
      Curl_llist_remove(&cb_ptr->conn_list, curr, NULL);
      cb_ptr->num_connections--;
      conn->bundle = NULL;
      return 1; /* we removed a handle */
    }
    curr = curr->next;
  }
  return 0;
}

static void free_bundle_hash_entry(void *freethis)
{
  struct connectbundle *b = (struct connectbundle *) freethis;

  bundle_destroy(b);
}

int Curl_conncache_init(struct conncache *connc, int size)
{
  int rc;

  /* allocate a new easy handle to use when closing cached connections */
  connc->closure_handle = curl_easy_init();
  if(!connc->closure_handle)
    return 1; /* bad */

  rc = Curl_hash_init(&connc->hash, size, Curl_hash_str,
                      Curl_str_key_compare, free_bundle_hash_entry);
  if(rc) {
    Curl_close(connc->closure_handle);
    connc->closure_handle = NULL;
  }
  else
    connc->closure_handle->state.conn_cache = connc;

  return rc;
}

void Curl_conncache_destroy(struct conncache *connc)
{
  if(connc)
    Curl_hash_destroy(&connc->hash);
}

/* creates a key to find a bundle for this connection */
static void hashkey(struct connectdata *conn, char *buf,
                    size_t len) /* something like 128 is fine */
{
  const char *hostname;

  if(conn->bits.socksproxy)
    hostname = conn->socks_proxy.host.name;
  else if(conn->bits.httpproxy)
    hostname = conn->http_proxy.host.name;
  else if(conn->bits.conn_to_host)
    hostname = conn->conn_to_host.name;
  else
    hostname = conn->host.name;

  DEBUGASSERT(len > 32);

  /* put the number first so that the hostname gets cut off if too long */
  snprintf(buf, len, "%ld%s", conn->port, hostname);
}

/* Look up the bundle with all the connections to the same host this
   connectdata struct is setup to use. */
struct connectbundle *Curl_conncache_find_bundle(struct connectdata *conn,
                                                 struct conncache *connc)
{
  struct connectbundle *bundle = NULL;
  if(connc) {
    char key[128];
    hashkey(conn, key, sizeof(key));
    CONN_LOCK(conn->data);
    bundle = Curl_hash_pick(&connc->hash, key, strlen(key));
    CONN_UNLOCK(conn->data);
  }

  return bundle;
}

static bool conncache_add_bundle(struct conncache *connc,
                                 char *key,
                                 struct connectbundle *bundle)
{
  void *p = Curl_hash_add(&connc->hash, key, strlen(key), bundle);

  return p?TRUE:FALSE;
}

static void conncache_remove_bundle(struct conncache *connc,
                                    struct connectbundle *bundle)
{
  struct curl_hash_iterator iter;
  struct curl_hash_element *he;

  if(!connc)
    return;

  Curl_hash_start_iterate(&connc->hash, &iter);

  he = Curl_hash_next_element(&iter);
  while(he) {
    if(he->ptr == bundle) {
      /* The bundle is destroyed by the hash destructor function,
         free_bundle_hash_entry() */
      Curl_hash_delete(&connc->hash, he->key, he->key_len);
      return;
    }

    he = Curl_hash_next_element(&iter);
  }
}

CURLcode Curl_conncache_add_conn(struct conncache *connc,
                                 struct connectdata *conn)
{
  CURLcode result;
  struct connectbundle *bundle;
  struct connectbundle *new_bundle = NULL;
  struct Curl_easy *data = conn->data;

  bundle = Curl_conncache_find_bundle(conn, data->state.conn_cache);
  if(!bundle) {
    int rc;
    char key[128];

    result = bundle_create(data, &new_bundle);
    if(result)
      return result;

    hashkey(conn, key, sizeof(key));
    CONN_LOCK(data);
    rc = conncache_add_bundle(data->state.conn_cache, key, new_bundle);
    CONN_UNLOCK(data);

    if(!rc) {
      bundle_destroy(new_bundle);
      return CURLE_OUT_OF_MEMORY;
    }
    bundle = new_bundle;
  }

  CONN_LOCK(data);
  result = bundle_add_conn(bundle, conn);
  if(result) {
    if(new_bundle)
      conncache_remove_bundle(data->state.conn_cache, new_bundle);
    CONN_UNLOCK(data);
    return result;
  }
  CONN_UNLOCK(data);

  conn->connection_id = connc->next_connection_id++;
  connc->num_connections++;

  DEBUGF(infof(conn->data, "Added connection %ld. "
               "The cache now contains %" CURL_FORMAT_CURL_OFF_TU " members\n",
               conn->connection_id, (curl_off_t) connc->num_connections));

  return CURLE_OK;
}

void Curl_conncache_remove_conn(struct conncache *connc,
                                struct connectdata *conn)
{
  struct connectbundle *bundle = conn->bundle;

  /* The bundle pointer can be NULL, since this function can be called
     due to a failed connection attempt, before being added to a bundle */
  if(bundle) {
    CONN_LOCK(conn->data);
    bundle_remove_conn(bundle, conn);
    if(bundle->num_connections == 0)
      conncache_remove_bundle(connc, bundle);
    CONN_UNLOCK(conn->data);
    if(connc) {
      connc->num_connections--;

      DEBUGF(infof(conn->data, "The cache now contains %"
                   CURL_FORMAT_CURL_OFF_TU " members\n",
                   (curl_off_t) connc->num_connections));
    }
  }
}

/* This function iterates the entire connection cache and calls the
   function func() with the connection pointer as the first argument
   and the supplied 'param' argument as the other,

   Return 0 from func() to continue the loop, return 1 to abort it.
 */
void Curl_conncache_foreach(struct Curl_easy *data,
                            struct conncache *connc,
                            void *param,
                            int (*func)(struct connectdata *conn, void *param))
{
  struct curl_hash_iterator iter;
  struct curl_llist_element *curr;
  struct curl_hash_element *he;

  if(!connc)
    return;

  CONN_LOCK(data);
  Curl_hash_start_iterate(&connc->hash, &iter);

  he = Curl_hash_next_element(&iter);
  while(he) {
    struct connectbundle *bundle;

    bundle = he->ptr;
    he = Curl_hash_next_element(&iter);

    curr = bundle->conn_list.head;
    while(curr) {
      /* Yes, we need to update curr before calling func(), because func()
         might decide to remove the connection */
      struct connectdata *conn = curr->ptr;
      curr = curr->next;

      if(1 == func(conn, param)) {
        CONN_UNLOCK(data);
        return;
      }
    }
  }
  CONN_UNLOCK(data);
}

/* Return the first connection found in the cache. Used when closing all
   connections.

   NOTE: no locking is done here as this is presumably only done when cleaning
   up a cache!
*/
struct connectdata *
Curl_conncache_find_first_connection(struct conncache *connc)
{
  struct curl_hash_iterator iter;
  struct curl_hash_element *he;
  struct connectbundle *bundle;

  Curl_hash_start_iterate(&connc->hash, &iter);

  he = Curl_hash_next_element(&iter);
  while(he) {
    struct curl_llist_element *curr;
    bundle = he->ptr;

    curr = bundle->conn_list.head;
    if(curr) {
      return curr->ptr;
    }

    he = Curl_hash_next_element(&iter);
  }

  return NULL;
}

/*
 * This function finds the connection in the connection
 * cache that has been unused for the longest time.
 *
 * Returns the pointer to the oldest idle connection, or NULL if none was
 * found.
 */
struct connectdata *
Curl_conncache_oldest_idle(struct Curl_easy *data)
{
  struct conncache *bc = data->state.conn_cache;
  struct curl_hash_iterator iter;
  struct curl_llist_element *curr;
  struct curl_hash_element *he;
  timediff_t highscore =- 1;
  timediff_t score;
  struct curltime now;
  struct connectdata *conn_candidate = NULL;
  struct connectbundle *bundle;

  now = Curl_now();

  CONN_LOCK(data);
  Curl_hash_start_iterate(&bc->hash, &iter);

  he = Curl_hash_next_element(&iter);
  while(he) {
    struct connectdata *conn;

    bundle = he->ptr;

    curr = bundle->conn_list.head;
    while(curr) {
      conn = curr->ptr;

      if(!conn->inuse) {
        /* Set higher score for the age passed since the connection was used */
        score = Curl_timediff(now, conn->now);

        if(score > highscore) {
          highscore = score;
          conn_candidate = conn;
        }
      }
      curr = curr->next;
    }

    he = Curl_hash_next_element(&iter);
  }
  CONN_UNLOCK(data);

  return conn_candidate;
}

void Curl_conncache_close_all_connections(struct conncache *connc)
{
  struct connectdata *conn;

  conn = Curl_conncache_find_first_connection(connc);
  while(conn) {
    SIGPIPE_VARIABLE(pipe_st);
    conn->data = connc->closure_handle;

    sigpipe_ignore(conn->data, &pipe_st);
    conn->data->easy_conn = NULL; /* clear the easy handle's connection
                                     pointer */
    /* This will remove the connection from the cache */
    connclose(conn, "kill all");
    (void)Curl_disconnect(conn, FALSE);
    sigpipe_restore(&pipe_st);

    conn = Curl_conncache_find_first_connection(connc);
  }

  if(connc->closure_handle) {
    SIGPIPE_VARIABLE(pipe_st);
    sigpipe_ignore(connc->closure_handle, &pipe_st);

    Curl_hostcache_clean(connc->closure_handle,
                         connc->closure_handle->dns.hostcache);
    Curl_close(connc->closure_handle);
    sigpipe_restore(&pipe_st);
  }
}

#if 0
/* Useful for debugging the connection cache */
void Curl_conncache_print(struct conncache *connc)
{
  struct curl_hash_iterator iter;
  struct curl_llist_element *curr;
  struct curl_hash_element *he;

  if(!connc)
    return;

  fprintf(stderr, "=Bundle cache=\n");

  Curl_hash_start_iterate(connc->hash, &iter);

  he = Curl_hash_next_element(&iter);
  while(he) {
    struct connectbundle *bundle;
    struct connectdata *conn;

    bundle = he->ptr;

    fprintf(stderr, "%s -", he->key);
    curr = bundle->conn_list->head;
    while(curr) {
      conn = curr->ptr;

      fprintf(stderr, " [%p %d]", (void *)conn, conn->inuse);
      curr = curr->next;
    }
    fprintf(stderr, "\n");

    he = Curl_hash_next_element(&iter);
  }
}
#endif