1 /* 2 * Copyright (c) 2010 Riccardo Panicucci, Luigi Rizzo, Universita` di Pisa 3 * All rights reserved 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 /* 28 * The API to write a packet scheduling algorithm for dummynet. 29 * 30 * $FreeBSD$ 31 */ 32 33 #ifndef _DN_SCHED_H 34 #define _DN_SCHED_H 35 36 #define DN_MULTIQUEUE 0x01 37 /* 38 * Descriptor for a scheduling algorithm. 39 * Contains all function pointers for a given scheduler 40 * This is typically created when a module is loaded, and stored 41 * in a global list of schedulers. 42 */ 43 struct dn_alg { 44 uint32_t type; /* the scheduler type */ 45 const char *name; /* scheduler name */ 46 uint32_t flags; /* DN_MULTIQUEUE if supports multiple queues */ 47 48 /* 49 * The following define the size of 3 optional data structures 50 * that may need to be allocated at runtime, and are appended 51 * to each of the base data structures: scheduler, sched.inst, 52 * and queue. We don't have a per-flowset structure. 53 */ 54 /* + parameters attached to the template, e.g. 55 * default queue sizes, weights, quantum size, and so on; 56 */ 57 size_t schk_datalen; 58 59 /* + per-instance parameters, such as timestamps, 60 * containers for queues, etc; 61 */ 62 size_t si_datalen; 63 64 size_t q_datalen; /* per-queue parameters (e.g. S,F) */ 65 66 /* 67 * Methods implemented by the scheduler: 68 * enqueue enqueue packet 'm' on scheduler 's', queue 'q'. 69 * q is NULL for !MULTIQUEUE. 70 * Return 0 on success, 1 on drop (packet consumed anyways). 71 * Note that q should be interpreted only as a hint 72 * on the flow that the mbuf belongs to: while a 73 * scheduler will normally enqueue m into q, it is ok 74 * to leave q alone and put the mbuf elsewhere. 75 * This function is called in two cases: 76 * - when a new packet arrives to the scheduler; 77 * - when a scheduler is reconfigured. In this case the 78 * call is issued by the new_queue callback, with a 79 * non empty queue (q) and m pointing to the first 80 * mbuf in the queue. For this reason, the function 81 * should internally check for (m != q->mq.head) 82 * before calling dn_enqueue(). 83 * 84 * dequeue Called when scheduler instance 's' can 85 * dequeue a packet. Return NULL if none are available. 86 * XXX what about non work-conserving ? 87 * 88 * config called on 'sched X config ...', normally writes 89 * in the area of size sch_arg 90 * 91 * destroy called on 'sched delete', frees everything 92 * in sch_arg (other parts are handled by more specific 93 * functions) 94 * 95 * new_sched called when a new instance is created, e.g. 96 * to create the local queue for !MULTIQUEUE, set V or 97 * copy parameters for WFQ, and so on. 98 * 99 * free_sched called when deleting an instance, cleans 100 * extra data in the per-instance area. 101 * 102 * new_fsk called when a flowset is linked to a scheduler, 103 * e.g. to validate parameters such as weights etc. 104 * free_fsk when a flowset is unlinked from a scheduler. 105 * (probably unnecessary) 106 * 107 * new_queue called to set the per-queue parameters, 108 * e.g. S and F, adjust sum of weights in the parent, etc. 109 * 110 * The new_queue callback is normally called from when 111 * creating a new queue. In some cases (such as a 112 * scheduler change or reconfiguration) it can be called 113 * with a non empty queue. In this case, the queue 114 * In case of non empty queue, the new_queue callback could 115 * need to call the enqueue function. In this case, 116 * the callback should eventually call enqueue() passing 117 * as m the first element in the queue. 118 * 119 * free_queue actions related to a queue removal, e.g. undo 120 * all the above. If the queue has data in it, also remove 121 * from the scheduler. This can e.g. happen during a reconfigure. 122 */ 123 int (*enqueue)(struct dn_sch_inst *, struct dn_queue *, 124 struct mbuf *); 125 struct mbuf * (*dequeue)(struct dn_sch_inst *); 126 127 int (*config)(struct dn_schk *); 128 int (*destroy)(struct dn_schk*); 129 int (*new_sched)(struct dn_sch_inst *); 130 int (*free_sched)(struct dn_sch_inst *); 131 int (*new_fsk)(struct dn_fsk *f); 132 int (*free_fsk)(struct dn_fsk *f); 133 int (*new_queue)(struct dn_queue *q); 134 int (*free_queue)(struct dn_queue *q); 135 136 /* run-time fields */ 137 int ref_count; /* XXX number of instances in the system */ 138 SLIST_ENTRY(dn_alg) next; /* Next scheduler in the list */ 139 }; 140 141 /* MSVC does not support initializers so we need this ugly macro */ 142 #ifdef _WIN32 143 #define _SI(fld) 144 #else 145 #define _SI(fld) fld 146 #endif 147 148 /* 149 * Additionally, dummynet exports some functions and macros 150 * to be used by schedulers: 151 */ 152 153 void dn_free_pkts(struct mbuf *mnext); 154 int dn_enqueue(struct dn_queue *q, struct mbuf* m, int drop); 155 /* bound a variable between min and max */ 156 int ipdn_bound_var(int *v, int dflt, int lo, int hi, const char *msg); 157 158 /* 159 * Extract the head of a queue, update stats. Must be the very last 160 * thing done on a dequeue as the queue itself may go away. 161 */ 162 static __inline struct mbuf* 163 dn_dequeue(struct dn_queue *q) 164 { 165 struct mbuf *m = q->mq.head; 166 if (m == NULL) 167 return NULL; 168 q->mq.head = m->m_nextpkt; 169 170 /* Update stats for the queue */ 171 q->ni.length--; 172 q->ni.len_bytes -= m->m_pkthdr.len; 173 if (q->_si) { 174 q->_si->ni.length--; 175 q->_si->ni.len_bytes -= m->m_pkthdr.len; 176 } 177 if (q->ni.length == 0) /* queue is now idle */ 178 q->q_time = dn_cfg.curr_time; 179 return m; 180 } 181 182 int dn_sched_modevent(module_t mod, int cmd, void *arg); 183 184 #define DECLARE_DNSCHED_MODULE(name, dnsched) \ 185 static moduledata_t name##_mod = { \ 186 #name, dn_sched_modevent, dnsched \ 187 }; \ 188 DECLARE_MODULE(name, name##_mod, \ 189 SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY); \ 190 MODULE_DEPEND(name, dummynet, 3, 3, 3); 191 #endif /* _DN_SCHED_H */ 192