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 <linux/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 = qdisc_priv(sch);
  49
  50         if (sch->qstats.backlog + skb->len <= q->limit) {
  51                 __skb_queue_tail(&sch->q, skb);
  52                 sch->qstats.backlog += skb->len;
  53                 sch->bstats.bytes += skb->len;
  54                 sch->bstats.packets++;
  55                 return 0;
  56         }
  57         sch->qstats.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->qstats.backlog += skb->len;
  70         sch->qstats.requeues++;
  71         return 0;
  72 }
  73
  74 static struct sk_buff *
  75 bfifo_dequeue(struct Qdisc* sch)
  76 {
  77         struct sk_buff *skb;
  78
  79         skb = __skb_dequeue(&sch->q);
  80         if (skb)
  81                 sch->qstats.backlog -= skb->len;
  82         return skb;
  83 }
  84
  85 static unsigned int
  86 fifo_drop(struct Qdisc* sch)
  87 {
  88         struct sk_buff *skb;
  89
  90         skb = __skb_dequeue_tail(&sch->q);
  91         if (skb) {
  92                 unsigned int len = skb->len;
  93                 sch->qstats.backlog -= len;
  94                 kfree_skb(skb);
  95                 return len;
  96         }
  97         return 0;
  98 }
  99
 100 static void
 101 fifo_reset(struct Qdisc* sch)
 102 {
 103         skb_queue_purge(&sch->q);
 104         sch->qstats.backlog = 0;
 105 }
 106
 107 static int
 108 pfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch)
 109 {
 110         struct fifo_sched_data *q = qdisc_priv(sch);
 111
 112         if (sch->q.qlen < q->limit) {
 113                 __skb_queue_tail(&sch->q, skb);
 114                 sch->bstats.bytes += skb->len;
 115                 sch->bstats.packets++;
 116                 return 0;
 117         }
 118         sch->qstats.drops++;
 119 #ifdef CONFIG_NET_CLS_POLICE
 120         if (sch->reshape_fail==NULL || sch->reshape_fail(skb, sch))
 121 #endif
 122                 kfree_skb(skb);
 123         return NET_XMIT_DROP;
 124 }
 125
 126 static int
 127 pfifo_requeue(struct sk_buff *skb, struct Qdisc* sch)
 128 {
 129         __skb_queue_head(&sch->q, skb);
 130         sch->qstats.requeues++;
 131         return 0;
 132 }
 133
 134
 135 static struct sk_buff *
 136 pfifo_dequeue(struct Qdisc* sch)
 137 {
 138         return __skb_dequeue(&sch->q);
 139 }
 140
 141 static int fifo_init(struct Qdisc *sch, struct rtattr *opt)
 142 {
 143         struct fifo_sched_data *q = qdisc_priv(sch);
 144
 145         if (opt == NULL) {
 146                 unsigned int limit = sch->dev->tx_queue_len ? : 1;
 147
 148                 if (sch->ops == &bfifo_qdisc_ops)
 149                         q->limit = limit*sch->dev->mtu;
 150                 else
 151                         q->limit = limit;
 152         } else {
 153                 struct tc_fifo_qopt *ctl = RTA_DATA(opt);
 154                 if (opt->rta_len < RTA_LENGTH(sizeof(*ctl)))
 155                         return -EINVAL;
 156                 q->limit = ctl->limit;
 157         }
 158         return 0;
 159 }
 160
 161 static int fifo_dump(struct Qdisc *sch, struct sk_buff *skb)
 162 {
 163         struct fifo_sched_data *q = qdisc_priv(sch);
 164         unsigned char    *b = skb->tail;
 165         struct tc_fifo_qopt opt;
 166
 167         opt.limit = q->limit;
 168         RTA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
 169
 170         return skb->len;
 171
 172 rtattr_failure:
 173         skb_trim(skb, b - skb->data);
 174         return -1;
 175 }
 176
 177 struct Qdisc_ops pfifo_qdisc_ops = {
 178         .next           =       NULL,
 179         .cl_ops         =       NULL,
 180         .id             =       "pfifo",
 181         .priv_size      =       sizeof(struct fifo_sched_data),
 182         .enqueue        =       pfifo_enqueue,
 183         .dequeue        =       pfifo_dequeue,
 184         .requeue        =       pfifo_requeue,
 185         .drop           =       fifo_drop,
 186         .init           =       fifo_init,
 187         .reset          =       fifo_reset,
 188         .destroy        =       NULL,
 189         .change         =       fifo_init,
 190         .dump           =       fifo_dump,
 191         .owner          =       THIS_MODULE,
 192 };
 193
 194 struct Qdisc_ops bfifo_qdisc_ops = {
 195         .next           =       NULL,
 196         .cl_ops         =       NULL,
 197         .id             =       "bfifo",
 198         .priv_size      =       sizeof(struct fifo_sched_data),
 199         .enqueue        =       bfifo_enqueue,
 200         .dequeue        =       bfifo_dequeue,
 201         .requeue        =       bfifo_requeue,
 202         .drop           =       fifo_drop,
 203         .init           =       fifo_init,
 204         .reset          =       fifo_reset,
 205         .destroy        =       NULL,
 206         .change         =       fifo_init,
 207         .dump           =       fifo_dump,
 208         .owner          =       THIS_MODULE,
 209 };
 210
 211 EXPORT_SYMBOL(bfifo_qdisc_ops);
 212 EXPORT_SYMBOL(pfifo_qdisc_ops);