1/* net/atm/atm_misc.c - Various functions for use by ATM drivers */
2
3/* Written 1995-2000 by Werner Almesberger, EPFL ICA */
4
5#include <linux/module.h>
6#include <linux/atm.h>
7#include <linux/atmdev.h>
8#include <linux/skbuff.h>
9#include <linux/sonet.h>
10#include <linux/bitops.h>
11#include <linux/errno.h>
12#include <linux/atomic.h>
13
14int atm_charge(struct atm_vcc *vcc, int truesize)
15{
16	atm_force_charge(vcc, truesize);
17	if (atomic_read(&sk_atm(vcc)->sk_rmem_alloc) <= sk_atm(vcc)->sk_rcvbuf)
18		return 1;
19	atm_return(vcc, truesize);
20	atomic_inc(&vcc->stats->rx_drop);
21	return 0;
22}
23EXPORT_SYMBOL(atm_charge);
24
25struct sk_buff *atm_alloc_charge(struct atm_vcc *vcc, int pdu_size,
26				 gfp_t gfp_flags)
27{
28	struct sock *sk = sk_atm(vcc);
29	int guess = SKB_TRUESIZE(pdu_size);
30
31	atm_force_charge(vcc, guess);
32	if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf) {
33		struct sk_buff *skb = alloc_skb(pdu_size, gfp_flags);
34
35		if (skb) {
36			atomic_add(skb->truesize-guess,
37				   &sk->sk_rmem_alloc);
38			return skb;
39		}
40	}
41	atm_return(vcc, guess);
42	atomic_inc(&vcc->stats->rx_drop);
43	return NULL;
44}
45EXPORT_SYMBOL(atm_alloc_charge);
46
47
48/*
49 * atm_pcr_goal returns the positive PCR if it should be rounded up, the
50 * negative PCR if it should be rounded down, and zero if the maximum available
51 * bandwidth should be used.
52 *
53 * The rules are as follows (* = maximum, - = absent (0), x = value "x",
54 * (x+ = x or next value above x, x- = x or next value below):
55 *
56 *	min max pcr	result		min max pcr	result
57 *	-   -   -	* (UBR only)	x   -   -	x+
58 *	-   -   *	*		x   -   *	*
59 *	-   -   z	z-		x   -   z	z-
60 *	-   *   -	*		x   *   -	x+
61 *	-   *   *	*		x   *   *	*
62 *	-   *   z	z-		x   *   z	z-
63 *	-   y   -	y-		x   y   -	x+
64 *	-   y   *	y-		x   y   *	y-
65 *	-   y   z	z-		x   y   z	z-
66 *
67 * All non-error cases can be converted with the following simple set of rules:
68 *
69 *   if pcr == z then z-
70 *   else if min == x && pcr == - then x+
71 *     else if max == y then y-
72 *	 else *
73 */
74
75int atm_pcr_goal(const struct atm_trafprm *tp)
76{
77	if (tp->pcr && tp->pcr != ATM_MAX_PCR)
78		return -tp->pcr;
79	if (tp->min_pcr && !tp->pcr)
80		return tp->min_pcr;
81	if (tp->max_pcr != ATM_MAX_PCR)
82		return -tp->max_pcr;
83	return 0;
84}
85EXPORT_SYMBOL(atm_pcr_goal);
86
87void sonet_copy_stats(struct k_sonet_stats *from, struct sonet_stats *to)
88{
89#define __HANDLE_ITEM(i) to->i = atomic_read(&from->i)
90	__SONET_ITEMS
91#undef __HANDLE_ITEM
92}
93EXPORT_SYMBOL(sonet_copy_stats);
94
95void sonet_subtract_stats(struct k_sonet_stats *from, struct sonet_stats *to)
96{
97#define __HANDLE_ITEM(i) atomic_sub(to->i, &from->i)
98	__SONET_ITEMS
99#undef __HANDLE_ITEM
100}
101EXPORT_SYMBOL(sonet_subtract_stats);
102