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
6 #include <linux/module.h>
7 #include <linux/atm.h>
8 #include <linux/atmdev.h>
9 #include <linux/skbuff.h>
10 #include <linux/sonet.h>
11 #include <linux/bitops.h>
12 #include <asm/atomic.h>
13 #include <asm/errno.h>
14
15
16 int atm_charge(struct atm_vcc *vcc,int truesize)
17 {
18 atm_force_charge(vcc,truesize);
19 if (atomic_read(&vcc->rx_inuse) <= vcc->sk->rcvbuf) return 1;
20 atm_return(vcc,truesize);
21 atomic_inc(&vcc->stats->rx_drop);
22 return 0;
23 }
24
25
26 struct sk_buff *atm_alloc_charge(struct atm_vcc *vcc,int pdu_size,
27 int gfp_flags)
28 {
29 int guess = atm_guess_pdu2truesize(pdu_size);
30
31 atm_force_charge(vcc,guess);
32 if (atomic_read(&vcc->rx_inuse) <= vcc->sk->rcvbuf) {
33 struct sk_buff *skb = alloc_skb(pdu_size,gfp_flags);
34
35 if (skb) {
36 atomic_add(skb->truesize-guess,&vcc->rx_inuse);
37 return skb;
38 }
39 }
40 atm_return(vcc,guess);
41 atomic_inc(&vcc->stats->rx_drop);
42 return NULL;
43 }
44
45
46 static int check_ci(struct atm_vcc *vcc,short vpi,int vci)
47 {
48 struct atm_vcc *walk;
49
50 for (walk = vcc->dev->vccs; walk; walk = walk->next)
51 if (test_bit(ATM_VF_ADDR,&walk->flags) && walk->vpi == vpi &&
52 walk->vci == vci && ((walk->qos.txtp.traffic_class !=
53 ATM_NONE && vcc->qos.txtp.traffic_class != ATM_NONE) ||
54 (walk->qos.rxtp.traffic_class != ATM_NONE &&
55 vcc->qos.rxtp.traffic_class != ATM_NONE)))
56 return -EADDRINUSE;
57 /* allow VCCs with same VPI/VCI iff they don't collide on
58 TX/RX (but we may refuse such sharing for other reasons,
59 e.g. if protocol requires to have both channels) */
60 return 0;
61 }
62
63
64 int atm_find_ci(struct atm_vcc *vcc,short *vpi,int *vci)
65 {
66 static short p = 0; /* poor man's per-device cache */
67 static int c = 0;
68 short old_p;
69 int old_c;
70
71 if (*vpi != ATM_VPI_ANY && *vci != ATM_VCI_ANY)
72 return check_ci(vcc,*vpi,*vci);
73 /* last scan may have left values out of bounds for current device */
74 if (*vpi != ATM_VPI_ANY) p = *vpi;
75 else if (p >= 1 << vcc->dev->ci_range.vpi_bits) p = 0;
76 if (*vci != ATM_VCI_ANY) c = *vci;
77 else if (c < ATM_NOT_RSV_VCI || c >= 1 << vcc->dev->ci_range.vci_bits)
78 c = ATM_NOT_RSV_VCI;
79 old_p = p;
80 old_c = c;
81 do {
82 if (!check_ci(vcc,p,c)) {
83 *vpi = p;
84 *vci = c;
85 return 0;
86 }
87 if (*vci == ATM_VCI_ANY) {
88 c++;
89 if (c >= 1 << vcc->dev->ci_range.vci_bits)
90 c = ATM_NOT_RSV_VCI;
91 }
92 if ((c == ATM_NOT_RSV_VCI || *vci != ATM_VCI_ANY) &&
93 *vpi == ATM_VPI_ANY) {
94 p++;
95 if (p >= 1 << vcc->dev->ci_range.vpi_bits) p = 0;
96 }
97 }
98 while (old_p != p || old_c != c);
99 return -EADDRINUSE;
100 }
101
102
103 /*
104 * atm_pcr_goal returns the positive PCR if it should be rounded up, the
105 * negative PCR if it should be rounded down, and zero if the maximum available
106 * bandwidth should be used.
107 *
108 * The rules are as follows (* = maximum, - = absent (0), x = value "x",
109 * (x+ = x or next value above x, x- = x or next value below):
110 *
111 * min max pcr result min max pcr result
112 * - - - * (UBR only) x - - x+
113 * - - * * x - * *
114 * - - z z- x - z z-
115 * - * - * x * - x+
116 * - * * * x * * *
117 * - * z z- x * z z-
118 * - y - y- x y - x+
119 * - y * y- x y * y-
120 * - y z z- x y z z-
121 *
122 * All non-error cases can be converted with the following simple set of rules:
123 *
124 * if pcr == z then z-
125 * else if min == x && pcr == - then x+
126 * else if max == y then y-
127 * else *
128 */
129
130
131 int atm_pcr_goal(struct atm_trafprm *tp)
132 {
133 if (tp->pcr && tp->pcr != ATM_MAX_PCR) return -tp->pcr;
134 if (tp->min_pcr && !tp->pcr) return tp->min_pcr;
135 if (tp->max_pcr != ATM_MAX_PCR) return -tp->max_pcr;
136 return 0;
137 }
138
139
140 void sonet_copy_stats(struct k_sonet_stats *from,struct sonet_stats *to)
141 {
142 #define __HANDLE_ITEM(i) to->i = atomic_read(&from->i)
143 __SONET_ITEMS
144 #undef __HANDLE_ITEM
145 }
146
147
148 void sonet_subtract_stats(struct k_sonet_stats *from,struct sonet_stats *to)
149 {
150 #define __HANDLE_ITEM(i) atomic_sub(to->i,&from->i)
151 __SONET_ITEMS
152 #undef __HANDLE_ITEM
153 }
154
155
156 EXPORT_SYMBOL(atm_charge);
157 EXPORT_SYMBOL(atm_alloc_charge);
158 EXPORT_SYMBOL(atm_find_ci);
159 EXPORT_SYMBOL(atm_pcr_goal);
160 EXPORT_SYMBOL(sonet_copy_stats);
161 EXPORT_SYMBOL(sonet_subtract_stats);
162
This page was automatically generated by the
LXR engine.
Visit the LXR main site for more
information.