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); 213