net/sched/sch_fifo.c

   1 /*
   2  * net/sched/sch_fifo.c The simplest FIFO queue.
   3  *
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  *
   9  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  10  */
  11
  12 #include <linux/config.h>
  13 #include <linux/module.h>
  14 #include <asm/uaccess.h>
  15 #include <asm/system.h>
  16 #include <asm/bitops.h>
  17 #include <linux/types.h>
  18 #include <linux/kernel.h>
  19 #include <linux/sched.h>
  20 #include <linux/string.h>
  21 #include <linux/mm.h>
  22 #include <linux/socket.h>
  23 #include <linux/sockios.h>
  24 #include <linux/in.h>
  25 #include <linux/errno.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/if_ether.h>
  28 #include <linux/inet.h>
  29 #include <linux/netdevice.h>
  30 #include <linux/etherdevice.h>
  31 #include <linux/notifier.h>
  32 #include <net/ip.h>
  33 #include <net/route.h>
  34 #include <linux/skbuff.h>
  35 #include <net/sock.h>
  36 #include <net/pkt_sched.h>
  37
  38 /* 1 band FIFO pseudo-"scheduler" */
  39
  40 struct fifo_sched_data
  41 {
  42         unsigned limit;
  43 };
  44
  45 static int
  46 bfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch)
  47 {
  48         struct fifo_sched_data *q = (struct fifo_sched_data *)sch->data;
  49
  50         if (sch->stats.backlog + skb->len <= q->limit) {
  51                 __skb_queue_tail(&sch->q, skb);
  52                 sch->stats.backlog += skb->len;
  53                 sch->stats.bytes += skb->len;
  54                 sch->stats.packets++;
  55                 return 0;
  56         }
  57         sch->stats.drops++;
  58 #ifdef CONFIG_NET_CLS_POLICE
  59         if (sch->reshape_fail==NULL || sch->reshape_fail(skb, sch))
  60 #endif
  61                 kfree_skb(skb);
  62         return NET_XMIT_DROP;
  63 }
  64
  65 static int
  66 bfifo_requeue(struct sk_buff *skb, struct Qdisc* sch)
  67 {
  68         __skb_queue_head(&sch->q, skb);
  69         sch->stats.backlog += skb->len;
  70         return 0;
  71 }
  72
  73 static struct sk_buff *
  74 bfifo_dequeue(struct Qdisc* sch)
  75 {
  76         struct sk_buff *skb;
  77
  78         skb = __skb_dequeue(&sch->q);
  79         if (skb)
  80                 sch->stats.backlog -= skb->len;
  81         return skb;
  82 }
  83
  84 static unsigned int
  85 fifo_drop(struct Qdisc* sch)
  86 {
  87         struct sk_buff *skb;
  88
  89         skb = __skb_dequeue_tail(&sch->q);
  90         if (skb) {
  91                 unsigned int len = skb->len;
  92                 sch->stats.backlog -= len;
  93                 kfree_skb(skb);
  94                 return len;
  95         }
  96         return 0;
  97 }
  98
  99 static void
 100 fifo_reset(struct Qdisc* sch)
 101 {
 102         skb_queue_purge(&sch->q);
 103         sch->stats.backlog = 0;
 104 }
 105
 106 static int
 107 pfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch)
 108 {
 109         struct fifo_sched_data *q = (struct fifo_sched_data *)sch->data;
 110
 111         if (sch->q.qlen < q->limit) {
 112                 __skb_queue_tail(&sch->q, skb);
 113                 sch->stats.bytes += skb->len;
 114                 sch->stats.packets++;
 115                 return 0;
 116         }
 117         sch->stats.drops++;
 118 #ifdef CONFIG_NET_CLS_POLICE
 119         if (sch->reshape_fail==NULL || sch->reshape_fail(skb, sch))
 120 #endif
 121                 kfree_skb(skb);
 122         return NET_XMIT_DROP;
 123 }
 124
 125 static int
 126 pfifo_requeue(struct sk_buff *skb, struct Qdisc* sch)
 127 {
 128         __skb_queue_head(&sch->q, skb);
 129         return 0;
 130 }
 131
 132
 133 static struct sk_buff *
 134 pfifo_dequeue(struct Qdisc* sch)
 135 {
 136         return __skb_dequeue(&sch->q);
 137 }
 138
 139 static int fifo_init(struct Qdisc *sch, struct rtattr *opt)
 140 {
 141         struct fifo_sched_data *q = (void*)sch->data;
 142
 143         if (opt == NULL) {
 144                 unsigned int limit = sch->dev->tx_queue_len ? : 1;
 145
 146                 if (sch->ops == &bfifo_qdisc_ops)
 147                         q->limit = limit*sch->dev->mtu;
 148                 else
 149                         q->limit = limit;
 150         } else {
 151                 struct tc_fifo_qopt *ctl = RTA_DATA(opt);
 152                 if (opt->rta_len < RTA_LENGTH(sizeof(*ctl)))
 153                         return -EINVAL;
 154                 q->limit = ctl->limit;
 155         }
 156         return 0;
 157 }
 158
 159 static int fifo_dump(struct Qdisc *sch, struct sk_buff *skb)
 160 {
 161         struct fifo_sched_data *q = (void*)sch->data;
 162         unsigned char    *b = skb->tail;
 163         struct tc_fifo_qopt opt;
 164
 165         opt.limit = q->limit;
 166         RTA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
 167
 168         return skb->len;
 169
 170 rtattr_failure:
 171         skb_trim(skb, b - skb->data);
 172         return -1;
 173 }
 174
 175 struct Qdisc_ops pfifo_qdisc_ops = {
 176         .next           =       NULL,
 177         .cl_ops         =       NULL,
 178         .id             =       "pfifo",
 179         .priv_size      =       sizeof(struct fifo_sched_data),
 180         .enqueue        =       pfifo_enqueue,
 181         .dequeue        =       pfifo_dequeue,
 182         .requeue        =       pfifo_requeue,
 183         .drop           =       fifo_drop,
 184         .init           =       fifo_init,
 185         .reset          =       fifo_reset,
 186         .destroy        =       NULL,
 187         .change         =       fifo_init,
 188         .dump           =       fifo_dump,
 189         .owner          =       THIS_MODULE,
 190 };
 191
 192 struct Qdisc_ops bfifo_qdisc_ops = {
 193         .next           =       NULL,
 194         .cl_ops         =       NULL,
 195         .id             =       "bfifo",
 196         .priv_size      =       sizeof(struct fifo_sched_data),
 197         .enqueue        =       bfifo_enqueue,
 198         .dequeue        =       bfifo_dequeue,
 199         .requeue        =       bfifo_requeue,
 200         .drop           =       fifo_drop,
 201         .init           =       fifo_init,
 202         .reset          =       fifo_reset,
 203         .destroy        =       NULL,
 204         .change         =       fifo_init,
 205         .dump           =       fifo_dump,
 206         .owner          =       THIS_MODULE,
 207 };
 208
 209 EXPORT_SYMBOL(bfifo_qdisc_ops);
 210 EXPORT_SYMBOL(pfifo_qdisc_ops);