2 * Copyright (c) 1998-2002 Luigi Rizzo, Universita` di Pisa
3 * Portions Copyright (c) 2000 Akamba Corp.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
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30 #ifndef _IP_DUMMYNET_H
31 #define _IP_DUMMYNET_H
34 * Definition of dummynet data structures. In the structures, I decided
35 * not to use the macros in <sys/queue.h> in the hope of making the code
36 * easier to port to other architectures. The type of lists and queue we
37 * use here is pretty simple anyways.
41 * We start with a heap, which is used in the scheduler to decide when
42 * to transmit packets etc.
44 * The key for the heap is used for two different values:
46 * 1. timer ticks- max 10K/second, so 32 bits are enough;
48 * 2. virtual times. These increase in steps of len/x, where len is the
49 * packet length, and x is either the weight of the flow, or the
51 * If we limit to max 1000 flows and a max weight of 100, then
52 * x needs 17 bits. The packet size is 16 bits, so we can easily
53 * overflow if we do not allow errors.
54 * So we use a key "dn_key" which is 64 bits. Some macros are used to
55 * compare key values and handle wraparounds.
56 * MAX64 returns the largest of two key values.
57 * MY_M is used as a shift count when doing fixed point arithmetic
58 * (a better name would be useful...).
60 typedef u_int64_t dn_key ; /* sorting key */
61 #define DN_KEY_LT(a,b) ((int64_t)((a)-(b)) < 0)
62 #define DN_KEY_LEQ(a,b) ((int64_t)((a)-(b)) <= 0)
63 #define DN_KEY_GT(a,b) ((int64_t)((a)-(b)) > 0)
64 #define DN_KEY_GEQ(a,b) ((int64_t)((a)-(b)) >= 0)
65 #define MAX64(x,y) (( (int64_t) ( (y)-(x) )) > 0 ) ? (y) : (x)
66 #define MY_M 16 /* number of left shift to obtain a larger precision */
69 * XXX With this scaling, max 1000 flows, max weight 100, 1Gbit/s, the
70 * virtual time wraps every 15 days.
74 * The OFFSET_OF macro is used to return the offset of a field within
75 * a structure. It is used by the heap management routines.
77 #define OFFSET_OF(type, field) ((int)&( ((type *)0)->field) )
80 * A heap entry is made of a key and a pointer to the actual
81 * object stored in the heap.
82 * The heap is an array of dn_heap_entry entries, dynamically allocated.
83 * Current size is "size", with "elements" actually in use.
84 * The heap normally supports only ordered insert and extract from the top.
85 * If we want to extract an object from the middle of the heap, we
86 * have to know where the object itself is located in the heap (or we
87 * need to scan the whole array). To this purpose, an object has a
88 * field (int) which contains the index of the object itself into the
89 * heap. When the object is moved, the field must also be updated.
90 * The offset of the index in the object is stored in the 'offset'
91 * field in the heap descriptor. The assumption is that this offset
92 * is non-zero if we want to support extract from the middle.
94 struct dn_heap_entry {
95 dn_key key ; /* sorting key. Topmost element is smallest one */
96 void *object ; /* object pointer */
102 int offset ; /* XXX if > 0 this is the offset of direct ptr to obj */
103 struct dn_heap_entry *p ; /* really an array of "size" entries */
107 * struct dn_pkt identifies a packet in the dummynet queue, but
108 * is also used to tag packets passed back to the various destinations
109 * (ip_input(), ip_output(), bdg_forward() and so on).
110 * As such the first part of the structure must be a struct m_hdr,
111 * followed by dummynet-specific parameters. The m_hdr must be
114 * mh_flags = PACKET_TYPE_DUMMYNET;
115 * mh_next = <pointer to the actual mbuf>
117 * mh_nextpkt, mh_data are free for dummynet use (mh_nextpkt is used to
118 * build a linked list of packets in a dummynet queue).
122 #define DN_NEXT(x) (struct dn_pkt *)(x)->hdr.mh_nextpkt
123 #define dn_m hdr.mh_next /* packet to be forwarded */
125 struct ip_fw *rule; /* matching rule */
126 int dn_dir; /* action when packet comes out. */
127 #define DN_TO_IP_OUT 1
128 #define DN_TO_IP_IN 2
129 #define DN_TO_BDG_FWD 3
130 #define DN_TO_ETH_DEMUX 4
131 #define DN_TO_ETH_OUT 5
133 dn_key output_time; /* when the pkt is due for delivery */
134 struct ifnet *ifp; /* interface, for ip_output */
135 struct sockaddr_in *dn_dst ;
136 struct route ro; /* route, for ip_output. MUST COPY */
137 int flags ; /* flags, for ip_output (IPv6 ?) */
141 * Overall structure of dummynet (with WF2Q+):
143 In dummynet, packets are selected with the firewall rules, and passed
144 to two different objects: PIPE or QUEUE.
146 A QUEUE is just a queue with configurable size and queue management
147 policy. It is also associated with a mask (to discriminate among
148 different flows), a weight (used to give different shares of the
149 bandwidth to different flows) and a "pipe", which essentially
150 supplies the transmit clock for all queues associated with that
153 A PIPE emulates a fixed-bandwidth link, whose bandwidth is
154 configurable. The "clock" for a pipe can come from either an
155 internal timer, or from the transmit interrupt of an interface.
156 A pipe is also associated with one (or more, if masks are used)
157 queue, where all packets for that pipe are stored.
159 The bandwidth available on the pipe is shared by the queues
160 associated with that pipe (only one in case the packet is sent
161 to a PIPE) according to the WF2Q+ scheduling algorithm and the
164 In general, incoming packets are stored in the appropriate queue,
165 which is then placed into one of a few heaps managed by a scheduler
166 to decide when the packet should be extracted.
167 The scheduler (a function called dummynet()) is run at every timer
168 tick, and grabs queues from the head of the heaps when they are
169 ready for processing.
171 There are three data structures definining a pipe and associated queues:
173 + dn_pipe, which contains the main configuration parameters related
174 to delay and bandwidth;
175 + dn_flow_set, which contains WF2Q+ configuration, flow
176 masks, plr and RED configuration;
177 + dn_flow_queue, which is the per-flow queue (containing the packets)
179 Multiple dn_flow_set can be linked to the same pipe, and multiple
180 dn_flow_queue can be linked to the same dn_flow_set.
181 All data structures are linked in a linear list which is used for
182 housekeeping purposes.
184 During configuration, we create and initialize the dn_flow_set
185 and dn_pipe structures (a dn_pipe also contains a dn_flow_set).
187 At runtime: packets are sent to the appropriate dn_flow_set (either
188 WFQ ones, or the one embedded in the dn_pipe for fixed-rate flows),
189 which in turn dispatches them to the appropriate dn_flow_queue
190 (created dynamically according to the masks).
192 The transmit clock for fixed rate flows (ready_event()) selects the
193 dn_flow_queue to be used to transmit the next packet. For WF2Q,
194 wfq_ready_event() extract a pipe which in turn selects the right
195 flow using a number of heaps defined into the pipe itself.
201 * per flow queue. This contains the flow identifier, the queue
202 * of packets, counters, and parameters used to support both RED and
205 * A dn_flow_queue is created and initialized whenever a packet for
206 * a new flow arrives.
208 struct dn_flow_queue {
209 struct dn_flow_queue *next ;
210 struct ipfw_flow_id id ;
212 struct dn_pkt *head, *tail ; /* queue of packets */
215 long numbytes ; /* credit for transmission (dynamic queues) */
217 u_int64_t tot_pkts ; /* statistics counters */
218 u_int64_t tot_bytes ;
221 int hash_slot ; /* debugging/diagnostic */
224 int avg ; /* average queue length est. (scaled) */
225 int count ; /* arrivals since last RED drop */
226 int random ; /* random value (scaled) */
227 u_int32_t q_time ; /* start of queue idle time */
230 struct dn_flow_set *fs ; /* parent flow set */
231 int heap_pos ; /* position (index) of struct in heap */
232 dn_key sched_time ; /* current time when queue enters ready_heap */
234 dn_key S,F ; /* start time, finish time */
236 * Setting F < S means the timestamp is invalid. We only need
237 * to test this when the queue is empty.
242 * flow_set descriptor. Contains the "template" parameters for the
243 * queue configuration, and pointers to the hash table of dn_flow_queue's.
245 * The hash table is an array of lists -- we identify the slot by
246 * hashing the flow-id, then scan the list looking for a match.
247 * The size of the hash table (buckets) is configurable on a per-queue
250 * A dn_flow_set is created whenever a new queue or pipe is created (in the
251 * latter case, the structure is located inside the struct dn_pipe).
254 struct dn_flow_set *next; /* next flow set in all_flow_sets list */
256 u_short fs_nr ; /* flow_set number */
258 #define DN_HAVE_FLOW_MASK 0x0001
259 #define DN_IS_RED 0x0002
260 #define DN_IS_GENTLE_RED 0x0004
261 #define DN_QSIZE_IS_BYTES 0x0008 /* queue size is measured in bytes */
262 #define DN_IS_PIPE 0x4000
263 #define DN_IS_QUEUE 0x8000
265 struct dn_pipe *pipe ; /* pointer to parent pipe */
266 u_short parent_nr ; /* parent pipe#, 0 if local to a pipe */
268 int weight ; /* WFQ queue weight */
269 int qsize ; /* queue size in slots or bytes */
270 int plr ; /* pkt loss rate (2^31-1 means 100%) */
272 struct ipfw_flow_id flow_mask ;
274 /* hash table of queues onto this flow_set */
275 int rq_size ; /* number of slots */
276 int rq_elements ; /* active elements */
277 struct dn_flow_queue **rq; /* array of rq_size entries */
279 u_int32_t last_expired ; /* do not expire too frequently */
280 int backlogged ; /* #active queues for this flowset */
284 #define SCALE(x) ( (x) << SCALE_RED )
285 #define SCALE_VAL(x) ( (x) >> SCALE_RED )
286 #define SCALE_MUL(x,y) ( ( (x) * (y) ) >> SCALE_RED )
287 int w_q ; /* queue weight (scaled) */
288 int max_th ; /* maximum threshold for queue (scaled) */
289 int min_th ; /* minimum threshold for queue (scaled) */
290 int max_p ; /* maximum value for p_b (scaled) */
291 u_int c_1 ; /* max_p/(max_th-min_th) (scaled) */
292 u_int c_2 ; /* max_p*min_th/(max_th-min_th) (scaled) */
293 u_int c_3 ; /* for GRED, (1-max_p)/max_th (scaled) */
294 u_int c_4 ; /* for GRED, 1 - 2*max_p (scaled) */
295 u_int * w_q_lookup ; /* lookup table for computing (1-w_q)^t */
296 u_int lookup_depth ; /* depth of lookup table */
297 int lookup_step ; /* granularity inside the lookup table */
298 int lookup_weight ; /* equal to (1-w_q)^t / (1-w_q)^(t+1) */
299 int avg_pkt_size ; /* medium packet size */
300 int max_pkt_size ; /* max packet size */
304 * Pipe descriptor. Contains global parameters, delay-line queue,
305 * and the flow_set used for fixed-rate queues.
307 * For WF2Q+ support it also has 3 heaps holding dn_flow_queue:
308 * not_eligible_heap, for queues whose start time is higher
309 * than the virtual time. Sorted by start time.
310 * scheduler_heap, for queues eligible for scheduling. Sorted by
312 * idle_heap, all flows that are idle and can be removed. We
313 * do that on each tick so we do not slow down too much
314 * operations during forwarding.
317 struct dn_pipe { /* a pipe */
318 struct dn_pipe *next ;
320 int pipe_nr ; /* number */
321 int bandwidth; /* really, bytes/tick. */
322 int delay ; /* really, ticks */
324 struct dn_pkt *head, *tail ; /* packets in delay line */
327 struct dn_heap scheduler_heap ; /* top extract - key Finish time*/
328 struct dn_heap not_eligible_heap; /* top extract- key Start time */
329 struct dn_heap idle_heap ; /* random extract - key Start=Finish time */
331 dn_key V ; /* virtual time */
332 int sum; /* sum of weights of all active sessions */
333 int numbytes; /* bits I can transmit (more or less). */
335 dn_key sched_time ; /* time pipe was scheduled in ready_heap */
338 * When the tx clock come from an interface (if_name[0] != '\0'), its name
339 * is stored below, whereas the ifp is filled when the rule is configured.
343 int ready ; /* set if ifp != NULL and we got a signal from it */
345 struct dn_flow_set fs ; /* used with fixed-rate flows */
349 typedef int ip_dn_ctl_t(struct sockopt *); /* raw_ip.c */
350 typedef void ip_dn_ruledel_t(void *); /* ip_fw.c */
351 typedef int ip_dn_io_t(struct mbuf *m, int pipe_nr, int dir,
352 struct ip_fw_args *fwa);
353 extern ip_dn_ctl_t *ip_dn_ctl_ptr;
354 extern ip_dn_ruledel_t *ip_dn_ruledel_ptr;
355 extern ip_dn_io_t *ip_dn_io_ptr;
356 #define DUMMYNET_LOADED (ip_dn_io_ptr != NULL)
359 #endif /* _IP_DUMMYNET_H */