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 0;
  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 NET_XMIT_DROP;
  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 0;
  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         skb_queue_purge(&sch->q);
 101         sch->stats.backlog = 0;
 102 }
 103
 104 static int
 105 pfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch)
 106 {
 107         struct fifo_sched_data *q = (struct fifo_sched_data *)sch->data;
 108
 109         if (sch->q.qlen <= q->limit) {
 110                 __skb_queue_tail(&sch->q, skb);
 111                 sch->stats.bytes += skb->len;
 112                 sch->stats.packets++;
 113                 return 0;
 114         }
 115         sch->stats.drops++;
 116 #ifdef CONFIG_NET_CLS_POLICE
 117         if (sch->reshape_fail==NULL || sch->reshape_fail(skb, sch))
 118 #endif
 119                 kfree_skb(skb);
 120         return NET_XMIT_DROP;
 121 }
 122
 123 static int
 124 pfifo_requeue(struct sk_buff *skb, struct Qdisc* sch)
 125 {
 126         __skb_queue_head(&sch->q, skb);
 127         return 0;
 128 }
 129
 130
 131 static struct sk_buff *
 132 pfifo_dequeue(struct Qdisc* sch)
 133 {
 134         return __skb_dequeue(&sch->q);
 135 }
 136
 137 static int fifo_init(struct Qdisc *sch, struct rtattr *opt)
 138 {
 139         struct fifo_sched_data *q = (void*)sch->data;
 140
 141         if (opt == NULL) {
 142                 if (sch->ops == &bfifo_qdisc_ops)
 143                         q->limit = sch->dev->tx_queue_len*sch->dev->mtu;
 144                 else
 145                         q->limit = sch->dev->tx_queue_len;
 146         } else {
 147                 struct tc_fifo_qopt *ctl = RTA_DATA(opt);
 148                 if (opt->rta_len < RTA_LENGTH(sizeof(*ctl)))
 149                         return -EINVAL;
 150                 q->limit = ctl->limit;
 151         }
 152         return 0;
 153 }
 154
 155 #ifdef CONFIG_RTNETLINK
 156 static int fifo_dump(struct Qdisc *sch, struct sk_buff *skb)
 157 {
 158         struct fifo_sched_data *q = (void*)sch->data;
 159         unsigned char    *b = skb->tail;
 160         struct tc_fifo_qopt opt;
 161
 162         opt.limit = q->limit;
 163         RTA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
 164
 165         return skb->len;
 166
 167 rtattr_failure:
 168         skb_trim(skb, b - skb->data);
 169         return -1;
 170 }
 171 #endif
 172
 173 struct Qdisc_ops pfifo_qdisc_ops =
 174 {
 175         NULL,
 176         NULL,
 177         "pfifo",
 178         sizeof(struct fifo_sched_data),
 179
 180         pfifo_enqueue,
 181         pfifo_dequeue,
 182         pfifo_requeue,
 183         fifo_drop,
 184
 185         fifo_init,
 186         fifo_reset,
 187         NULL,
 188         fifo_init,
 189
 190 #ifdef CONFIG_RTNETLINK
 191         fifo_dump,
 192 #endif
 193 };
 194
 195 struct Qdisc_ops bfifo_qdisc_ops =
 196 {
 197         NULL,
 198         NULL,
 199         "bfifo",
 200         sizeof(struct fifo_sched_data),
 201
 202         bfifo_enqueue,
 203         bfifo_dequeue,
 204         bfifo_requeue,
 205         fifo_drop,
 206
 207         fifo_init,
 208         fifo_reset,
 209         NULL,
 210         fifo_init,
 211 #ifdef CONFIG_RTNETLINK
 212         fifo_dump,
 213 #endif
 214 };