/*
   *  net/dccp/ccid.c
   *
   *  An implementation of the DCCP protocol
   *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
   *
   *  CCID infrastructure
   *
   *	This program is free software; you can redistribute it and/or modify it
   *	under the terms of the GNU General Public License version 2 as
   *	published by the Free Software Foundation.
   */
  
  #include <linux/slab.h>
  
  #include "ccid.h"
  #include "ccids/lib/tfrc.h"
  
  static struct ccid_operations *ccids[] = {
  	&ccid2_ops,
  #ifdef CONFIG_IP_DCCP_CCID3
  	&ccid3_ops,
  #endif
  };
  
  static struct ccid_operations *ccid_by_number(const u8 id)
  {
  	int i;
  
  	for (i = 0; i < ARRAY_SIZE(ccids); i++)
  		if (ccids[i]->ccid_id == id)
  			return ccids[i];
  	return NULL;
  }
  
  /* check that up to @array_len members in @ccid_array are supported */
  bool ccid_support_check(u8 const *ccid_array, u8 array_len)
  {
  	while (array_len > 0)
  		if (ccid_by_number(ccid_array[--array_len]) == NULL)
  			return false;
  	return true;
  }
  
  /**
   * ccid_get_builtin_ccids  -  Populate a list of built-in CCIDs
   * @ccid_array: pointer to copy into
   * @array_len: value to return length into
   *
   * This function allocates memory - caller must see that it is freed after use.
   */
  int ccid_get_builtin_ccids(u8 **ccid_array, u8 *array_len)
  {
  	*ccid_array = kmalloc(ARRAY_SIZE(ccids), gfp_any());
  	if (*ccid_array == NULL)
  		return -ENOBUFS;
  
  	for (*array_len = 0; *array_len < ARRAY_SIZE(ccids); *array_len += 1)
  		(*ccid_array)[*array_len] = ccids[*array_len]->ccid_id;
  	return 0;
  }
  
  int ccid_getsockopt_builtin_ccids(struct sock *sk, int len,
  				  char __user *optval, int __user *optlen)
  {
  	u8 *ccid_array, array_len;
  	int err = 0;
  
  	if (ccid_get_builtin_ccids(&ccid_array, &array_len))
  		return -ENOBUFS;
  
  	if (put_user(array_len, optlen))
  		err = -EFAULT;
  	else if (len > 0 && copy_to_user(optval, ccid_array,
  					 len > array_len ? array_len : len))
  		err = -EFAULT;
  
  	kfree(ccid_array);
  	return err;
  }
  
  static struct kmem_cache *ccid_kmem_cache_create(int obj_size, char *slab_name_fmt, const char *fmt,...)
  {
  	struct kmem_cache *slab;
  	va_list args;
  
  	va_start(args, fmt);
  	vsnprintf(slab_name_fmt, CCID_SLAB_NAME_LENGTH, fmt, args);
  	va_end(args);
  
  	slab = kmem_cache_create(slab_name_fmt, sizeof(struct ccid) + obj_size, 0,
  				 SLAB_HWCACHE_ALIGN, NULL);
  	return slab;
  }
  
  static void ccid_kmem_cache_destroy(struct kmem_cache *slab)
  {
  	if (slab != NULL)
  		kmem_cache_destroy(slab);
  }
  
  static int ccid_activate(struct ccid_operations *ccid_ops)
  {
  	int err = -ENOBUFS;
  
  	ccid_ops->ccid_hc_rx_slab =
  			ccid_kmem_cache_create(ccid_ops->ccid_hc_rx_obj_size,
  					       ccid_ops->ccid_hc_rx_slab_name,
  					       "ccid%u_hc_rx_sock",
  					       ccid_ops->ccid_id);
  	if (ccid_ops->ccid_hc_rx_slab == NULL)
  		goto out;
  
  	ccid_ops->ccid_hc_tx_slab =
  			ccid_kmem_cache_create(ccid_ops->ccid_hc_tx_obj_size,
  					       ccid_ops->ccid_hc_tx_slab_name,
  					       "ccid%u_hc_tx_sock",
  					       ccid_ops->ccid_id);
  	if (ccid_ops->ccid_hc_tx_slab == NULL)
  		goto out_free_rx_slab;
  
  	pr_info("DCCP: Activated CCID %d (%s)
  ",
  		ccid_ops->ccid_id, ccid_ops->ccid_name);
  	err = 0;
  out:
  	return err;
  out_free_rx_slab:
  	ccid_kmem_cache_destroy(ccid_ops->ccid_hc_rx_slab);
  	ccid_ops->ccid_hc_rx_slab = NULL;
  	goto out;
  }
  
  static void ccid_deactivate(struct ccid_operations *ccid_ops)
  {
  	ccid_kmem_cache_destroy(ccid_ops->ccid_hc_tx_slab);
  	ccid_ops->ccid_hc_tx_slab = NULL;
  	ccid_kmem_cache_destroy(ccid_ops->ccid_hc_rx_slab);
  	ccid_ops->ccid_hc_rx_slab = NULL;
  
  	pr_info("DCCP: Deactivated CCID %d (%s)
  ",
  		ccid_ops->ccid_id, ccid_ops->ccid_name);
  }
  
  struct ccid *ccid_new(const u8 id, struct sock *sk, bool rx)
  {
  	struct ccid_operations *ccid_ops = ccid_by_number(id);
  	struct ccid *ccid = NULL;
  
  	if (ccid_ops == NULL)
  		goto out;
  
  	ccid = kmem_cache_alloc(rx ? ccid_ops->ccid_hc_rx_slab :
  				     ccid_ops->ccid_hc_tx_slab, gfp_any());
  	if (ccid == NULL)
  		goto out;
  	ccid->ccid_ops = ccid_ops;
  	if (rx) {
  		memset(ccid + 1, 0, ccid_ops->ccid_hc_rx_obj_size);
  		if (ccid->ccid_ops->ccid_hc_rx_init != NULL &&
  		    ccid->ccid_ops->ccid_hc_rx_init(ccid, sk) != 0)
  			goto out_free_ccid;
  	} else {
  		memset(ccid + 1, 0, ccid_ops->ccid_hc_tx_obj_size);
  		if (ccid->ccid_ops->ccid_hc_tx_init != NULL &&
  		    ccid->ccid_ops->ccid_hc_tx_init(ccid, sk) != 0)
  			goto out_free_ccid;
  	}
  out:
  	return ccid;
  out_free_ccid:
  	kmem_cache_free(rx ? ccid_ops->ccid_hc_rx_slab :
  			ccid_ops->ccid_hc_tx_slab, ccid);
  	ccid = NULL;
  	goto out;
  }
  
  void ccid_hc_rx_delete(struct ccid *ccid, struct sock *sk)
  {
  	if (ccid != NULL) {
  		if (ccid->ccid_ops->ccid_hc_rx_exit != NULL)
  			ccid->ccid_ops->ccid_hc_rx_exit(sk);
  		kmem_cache_free(ccid->ccid_ops->ccid_hc_rx_slab, ccid);
  	}
  }
  
  void ccid_hc_tx_delete(struct ccid *ccid, struct sock *sk)
  {
  	if (ccid != NULL) {
  		if (ccid->ccid_ops->ccid_hc_tx_exit != NULL)
  			ccid->ccid_ops->ccid_hc_tx_exit(sk);
  		kmem_cache_free(ccid->ccid_ops->ccid_hc_tx_slab, ccid);
  	}
  }
  
  int __init ccid_initialize_builtins(void)
  {
  	int i, err = tfrc_lib_init();
  
  	if (err)
  		return err;
  
  	for (i = 0; i < ARRAY_SIZE(ccids); i++) {
  		err = ccid_activate(ccids[i]);
  		if (err)
  			goto unwind_registrations;
  	}
  	return 0;
  
  unwind_registrations:
  	while(--i >= 0)
  		ccid_deactivate(ccids[i]);
  	tfrc_lib_exit();
  	return err;
  }
  
  void ccid_cleanup_builtins(void)
  {
  	int i;
  
  	for (i = 0; i < ARRAY_SIZE(ccids); i++)
  		ccid_deactivate(ccids[i]);
  	tfrc_lib_exit();
  }