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 <asm/uaccess.h>
  14 #include <asm/system.h>
  15 #include <asm/bitops.h>
  16 #include <linux/types.h>
  17 #include <linux/kernel.h>
  18 #include <linux/sched.h>
  19 #include <linux/string.h>
  20 #include <linux/mm.h>
  21 #include <linux/socket.h>
  22 #include <linux/sockios.h>
  23 #include <linux/in.h>
  24 #include <linux/errno.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/if_ether.h>
  27 #include <linux/inet.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/etherdevice.h>
  30 #include <linux/notifier.h>
  31 #include <net/ip.h>
  32 #include <net/route.h>
  33 #include <linux/skbuff.h>
  34 #include <net/sock.h>
  35 #include <net/pkt_sched.h>
  36
  37 /* 1 band FIFO pseudo-"scheduler" */
  38
  39 struct fifo_sched_data
  40 {
  41         unsigned limit;
  42 };
  43
  44 static int
  45 bfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch)
  46 {
  47         struct fifo_sched_data *q = (struct fifo_sched_data *)sch->data;
  48
  49         if (sch->stats.backlog <= q->limit) {
  50                 __skb_queue_tail(&sch->q, skb);
  51                 sch->stats.backlog += skb->len;
  52                 sch->stats.bytes += skb->len;
  53                 sch->stats.packets++;
  54                 return 1;
  55         }
  56         sch->stats.drops++;
  57 #ifdef CONFIG_NET_CLS_POLICE
  58         if (sch->reshape_fail==NULL || sch->reshape_fail(skb, sch))
  59 #endif
  60                 kfree_skb(skb);
  61         return 0;
  62 }
  63
  64 static int
  65 bfifo_requeue(struct sk_buff *skb, struct Qdisc* sch)
  66 {
  67         __skb_queue_head(&sch->q, skb);
  68         sch->stats.backlog += skb->len;
  69         return 1;
  70 }
  71
  72 static struct sk_buff *
  73 bfifo_dequeue(struct Qdisc* sch)
  74 {
  75         struct sk_buff *skb;
  76
  77         skb = __skb_dequeue(&sch->q);
  78         if (skb)
  79                 sch->stats.backlog -= skb->len;
  80         return skb;
  81 }
  82
  83 static int
  84 fifo_drop(struct Qdisc* sch)
  85 {
  86         struct sk_buff *skb;
  87
  88         skb = __skb_dequeue_tail(&sch->q);
  89         if (skb) {
  90                 sch->stats.backlog -= skb->len;
  91                 kfree_skb(skb);
  92                 return 1;
  93         }
  94         return 0;
  95 }
  96
  97 static void
  98 fifo_reset(struct Qdisc* sch)
  99 {
 100         struct sk_buff *skb;
 101
 102         while ((skb=__skb_dequeue(&sch->q)) != NULL)
 103                 kfree_skb(skb);
 104         sch->stats.backlog = 0;
 105 }
 106
 107 static int
 108 pfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch)
 109 {
 110         struct fifo_sched_data *q = (struct fifo_sched_data *)sch->data;
 111
 112         if (sch->q.qlen <= q->limit) {
 113                 __skb_queue_tail(&sch->q, skb);
 114                 sch->stats.bytes += skb->len;
 115                 sch->stats.packets++;
 116                 return 1;
 117         }
 118         sch->stats.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 0;
 124 }
 125
 126 static int
 127 pfifo_requeue(struct sk_buff *skb, struct Qdisc* sch)
 128 {
 129         __skb_queue_head(&sch->q, skb);
 130         return 1;
 131 }
 132
 133
 134 static struct sk_buff *
 135 pfifo_dequeue(struct Qdisc* sch)
 136 {
 137         return __skb_dequeue(&sch->q);
 138 }
 139
 140
 141 static int fifo_init(struct Qdisc *sch, struct rtattr *opt)
 142 {
 143         struct fifo_sched_data *q = (void*)sch->data;
 144
 145         if (opt == NULL) {
 146                 q->limit = sch->dev->tx_queue_len;
 147                 if (sch->ops == &bfifo_qdisc_ops)
 148                         q->limit *= sch->dev->mtu;
 149         } else {
 150                 struct tc_fifo_qopt *ctl = RTA_DATA(opt);
 151                 if (opt->rta_len < RTA_LENGTH(sizeof(*ctl)))
 152                         return -EINVAL;
 153                 q->limit = ctl->limit;
 154         }
 155         return 0;
 156 }
 157
 158 #ifdef CONFIG_RTNETLINK
 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 #endif
 175
 176 struct Qdisc_ops pfifo_qdisc_ops =
 177 {
 178         NULL,
 179         NULL,
 180         "pfifo",
 181         sizeof(struct fifo_sched_data),
 182
 183         pfifo_enqueue,
 184         pfifo_dequeue,
 185         pfifo_requeue,
 186         fifo_drop,
 187
 188         fifo_init,
 189         fifo_reset,
 190         NULL,
 191 #ifdef CONFIG_RTNETLINK
 192         fifo_dump,
 193 #endif
 194 };
 195
 196 struct Qdisc_ops bfifo_qdisc_ops =
 197 {
 198         NULL,
 199         NULL,
 200         "bfifo",
 201         sizeof(struct fifo_sched_data),
 202
 203         bfifo_enqueue,
 204         bfifo_dequeue,
 205         bfifo_requeue,
 206         fifo_drop,
 207
 208         fifo_init,
 209         fifo_reset,
 210         NULL,
 211 #ifdef CONFIG_RTNETLINK
 212         fifo_dump,
 213 #endif
 214 };