| blob | c13b85061dfb531ebfabe1c23aac73ed28ca32eb |
1 /* SPDX-License-Identifier: MIT */
2 /******************************************************************************
3 * netif.h
4 *
5 * Unified network-device I/O interface for Xen guest OSes.
6 *
7 * Copyright (c) 2003-2004, Keir Fraser
8 */
10 #ifndef __XEN_PUBLIC_IO_NETIF_H__
11 #define __XEN_PUBLIC_IO_NETIF_H__
16 /*
17 * Older implementation of Xen network frontend / backend has an
18 * implicit dependency on the MAX_SKB_FRAGS as the maximum number of
19 * ring slots a skb can use. Netfront / netback may not work as
20 * expected when frontend and backend have different MAX_SKB_FRAGS.
21 *
22 * A better approach is to add mechanism for netfront / netback to
23 * negotiate this value. However we cannot fix all possible
24 * frontends, so we need to define a value which states the minimum
25 * slots backend must support.
26 *
27 * The minimum value derives from older Linux kernel's MAX_SKB_FRAGS
28 * (18), which is proved to work with most frontends. Any new backend
29 * which doesn't negotiate with frontend should expect frontend to
30 * send a valid packet using slots up to this value.
31 */
32 #define XEN_NETIF_NR_SLOTS_MIN 18
34 /*
35 * Notifications after enqueuing any type of message should be conditional on
36 * the appropriate req_event or rsp_event field in the shared ring.
37 * If the client sends notification for rx requests then it should specify
38 * feature 'feature-rx-notify' via xenbus. Otherwise the backend will assume
39 * that it cannot safely queue packets (as it may not be kicked to send them).
40 */
42 /*
43 * "feature-split-event-channels" is introduced to separate guest TX
44 * and RX notification. Backend either doesn't support this feature or
45 * advertises it via xenstore as 0 (disabled) or 1 (enabled).
46 *
47 * To make use of this feature, frontend should allocate two event
48 * channels for TX and RX, advertise them to backend as
49 * "event-channel-tx" and "event-channel-rx" respectively. If frontend
50 * doesn't want to use this feature, it just writes "event-channel"
51 * node as before.
52 */
54 /*
55 * Multiple transmit and receive queues:
56 * If supported, the backend will write the key "multi-queue-max-queues" to
57 * the directory for that vif, and set its value to the maximum supported
58 * number of queues.
59 * Frontends that are aware of this feature and wish to use it can write the
60 * key "multi-queue-num-queues", set to the number they wish to use, which
61 * must be greater than zero, and no more than the value reported by the backend
62 * in "multi-queue-max-queues".
63 *
64 * Queues replicate the shared rings and event channels.
65 * "feature-split-event-channels" may optionally be used when using
66 * multiple queues, but is not mandatory.
67 *
68 * Each queue consists of one shared ring pair, i.e. there must be the same
69 * number of tx and rx rings.
70 *
71 * For frontends requesting just one queue, the usual event-channel and
72 * ring-ref keys are written as before, simplifying the backend processing
73 * to avoid distinguishing between a frontend that doesn't understand the
74 * multi-queue feature, and one that does, but requested only one queue.
75 *
76 * Frontends requesting two or more queues must not write the toplevel
77 * event-channel (or event-channel-{tx,rx}) and {tx,rx}-ring-ref keys,
78 * instead writing those keys under sub-keys having the name "queue-N" where
79 * N is the integer ID of the queue for which those keys belong. Queues
80 * are indexed from zero. For example, a frontend with two queues and split
81 * event channels must write the following set of queue-related keys:
82 *
83 * /local/domain/1/device/vif/0/multi-queue-num-queues = "2"
84 * /local/domain/1/device/vif/0/queue-0 = ""
85 * /local/domain/1/device/vif/0/queue-0/tx-ring-ref = "<ring-ref-tx0>"
86 * /local/domain/1/device/vif/0/queue-0/rx-ring-ref = "<ring-ref-rx0>"
87 * /local/domain/1/device/vif/0/queue-0/event-channel-tx = "<evtchn-tx0>"
88 * /local/domain/1/device/vif/0/queue-0/event-channel-rx = "<evtchn-rx0>"
89 * /local/domain/1/device/vif/0/queue-1 = ""
90 * /local/domain/1/device/vif/0/queue-1/tx-ring-ref = "<ring-ref-tx1>"
91 * /local/domain/1/device/vif/0/queue-1/rx-ring-ref = "<ring-ref-rx1"
92 * /local/domain/1/device/vif/0/queue-1/event-channel-tx = "<evtchn-tx1>"
93 * /local/domain/1/device/vif/0/queue-1/event-channel-rx = "<evtchn-rx1>"
94 *
95 * If there is any inconsistency in the XenStore data, the backend may
96 * choose not to connect any queues, instead treating the request as an
97 * error. This includes scenarios where more (or fewer) queues were
98 * requested than the frontend provided details for.
99 *
100 * Mapping of packets to queues is considered to be a function of the
101 * transmitting system (backend or frontend) and is not negotiated
102 * between the two. Guests are free to transmit packets on any queue
103 * they choose, provided it has been set up correctly. Guests must be
104 * prepared to receive packets on any queue they have requested be set up.
105 */
107 /*
108 * "feature-no-csum-offload" should be used to turn IPv4 TCP/UDP checksum
109 * offload off or on. If it is missing then the feature is assumed to be on.
110 * "feature-ipv6-csum-offload" should be used to turn IPv6 TCP/UDP checksum
111 * offload on or off. If it is missing then the feature is assumed to be off.
112 */
114 /*
115 * "feature-gso-tcpv4" and "feature-gso-tcpv6" advertise the capability to
116 * handle large TCP packets (in IPv4 or IPv6 form respectively). Neither
117 * frontends nor backends are assumed to be capable unless the flags are
118 * present.
119 */
121 /*
122 * "feature-multicast-control" and "feature-dynamic-multicast-control"
123 * advertise the capability to filter ethernet multicast packets in the
124 * backend. If the frontend wishes to take advantage of this feature then
125 * it may set "request-multicast-control". If the backend only advertises
126 * "feature-multicast-control" then "request-multicast-control" must be set
127 * before the frontend moves into the connected state. The backend will
128 * sample the value on this state transition and any subsequent change in
129 * value will have no effect. However, if the backend also advertises
130 * "feature-dynamic-multicast-control" then "request-multicast-control"
131 * may be set by the frontend at any time. In this case, the backend will
132 * watch the value and re-sample on watch events.
133 *
134 * If the sampled value of "request-multicast-control" is set then the
135 * backend transmit side should no longer flood multicast packets to the
136 * frontend, it should instead drop any multicast packet that does not
137 * match in a filter list.
138 * The list is amended by the frontend by sending dummy transmit requests
139 * containing XEN_NETIF_EXTRA_TYPE_MCAST_{ADD,DEL} extra-info fragments as
140 * specified below.
141 * Note that the filter list may be amended even if the sampled value of
142 * "request-multicast-control" is not set, however the filter should only
143 * be applied if it is set.
144 */
146 /*
147 * The setting of "trusted" node to "0" in the frontend path signals that the
148 * frontend should not trust the backend, and should deploy whatever measures
149 * available to protect from a malicious backend on the other end.
150 */
152 /*
153 * Control ring
154 * ============
155 *
156 * Some features, such as hashing (detailed below), require a
157 * significant amount of out-of-band data to be passed from frontend to
158 * backend. Use of xenstore is not suitable for large quantities of data
159 * because of quota limitations and so a dedicated 'control ring' is used.
160 * The ability of the backend to use a control ring is advertised by
161 * setting:
162 *
163 * /local/domain/X/backend/vif/<domid>/<vif>/feature-ctrl-ring = "1"
164 *
165 * The frontend provides a control ring to the backend by setting:
166 *
167 * /local/domain/<domid>/device/vif/<vif>/ctrl-ring-ref = <gref>
168 * /local/domain/<domid>/device/vif/<vif>/event-channel-ctrl = <port>
169 *
170 * where <gref> is the grant reference of the shared page used to
171 * implement the control ring and <port> is an event channel to be used
172 * as a mailbox interrupt. These keys must be set before the frontend
173 * moves into the connected state.
174 *
175 * The control ring uses a fixed request/response message size and is
176 * balanced (i.e. one request to one response), so operationally it is much
177 * the same as a transmit or receive ring.
178 * Note that there is no requirement that responses are issued in the same
179 * order as requests.
180 */
182 /*
183 * Link state
184 * ==========
185 *
186 * The backend can advertise its current link (carrier) state to the
187 * frontend using the /local/domain/X/backend/vif/<domid>/<vif>/carrier
188 * node. If this node is not present, then the frontend should assume that
189 * the link is up (for compatibility with backends that do not implement
190 * this feature). If this node is present, then a value of "0" should be
191 * interpreted by the frontend as the link being down (no carrier) and a
192 * value of "1" should be interpreted as the link being up (carrier
193 * present).
194 */
196 /*
197 * MTU
198 * ===
199 *
200 * The toolstack may set a value of MTU for the frontend by setting the
201 * /local/domain/<domid>/device/vif/<vif>/mtu node with the MTU value in
202 * octets. If this node is absent the frontend should assume an MTU value
203 * of 1500 octets. A frontend is also at liberty to ignore this value so
204 * it is only suitable for informing the frontend that a packet payload
205 * >1500 octets is permitted.
206 */
208 /*
209 * Hash types
210 * ==========
211 *
212 * For the purposes of the definitions below, 'Packet[]' is an array of
213 * octets containing an IP packet without options, 'Array[X..Y]' means a
214 * sub-array of 'Array' containing bytes X thru Y inclusive, and '+' is
215 * used to indicate concatenation of arrays.
216 */
218 /*
219 * A hash calculated over an IP version 4 header as follows:
220 *
221 * Buffer[0..8] = Packet[12..15] (source address) +
222 * Packet[16..19] (destination address)
223 *
224 * Result = Hash(Buffer, 8)
225 */
226 #define _XEN_NETIF_CTRL_HASH_TYPE_IPV4 0
227 #define XEN_NETIF_CTRL_HASH_TYPE_IPV4 \
228 (1 << _XEN_NETIF_CTRL_HASH_TYPE_IPV4)
230 /*
231 * A hash calculated over an IP version 4 header and TCP header as
232 * follows:
233 *
234 * Buffer[0..12] = Packet[12..15] (source address) +
235 * Packet[16..19] (destination address) +
236 * Packet[20..21] (source port) +
237 * Packet[22..23] (destination port)
238 *
239 * Result = Hash(Buffer, 12)
240 */
241 #define _XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP 1
242 #define XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP \
243 (1 << _XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP)
245 /*
246 * A hash calculated over an IP version 6 header as follows:
247 *
248 * Buffer[0..32] = Packet[8..23] (source address ) +
249 * Packet[24..39] (destination address)
250 *
251 * Result = Hash(Buffer, 32)
252 */
253 #define _XEN_NETIF_CTRL_HASH_TYPE_IPV6 2
254 #define XEN_NETIF_CTRL_HASH_TYPE_IPV6 \
255 (1 << _XEN_NETIF_CTRL_HASH_TYPE_IPV6)
257 /*
258 * A hash calculated over an IP version 6 header and TCP header as
259 * follows:
260 *
261 * Buffer[0..36] = Packet[8..23] (source address) +
262 * Packet[24..39] (destination address) +
263 * Packet[40..41] (source port) +
264 * Packet[42..43] (destination port)
265 *
266 * Result = Hash(Buffer, 36)
267 */
268 #define _XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP 3
269 #define XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP \
270 (1 << _XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP)
272 /*
273 * Hash algorithms
274 * ===============
275 */
277 #define XEN_NETIF_CTRL_HASH_ALGORITHM_NONE 0
279 /*
280 * Toeplitz hash:
281 */
283 #define XEN_NETIF_CTRL_HASH_ALGORITHM_TOEPLITZ 1
285 /*
286 * This algorithm uses a 'key' as well as the data buffer itself.
287 * (Buffer[] and Key[] are treated as shift-registers where the MSB of
288 * Buffer/Key[0] is considered 'left-most' and the LSB of Buffer/Key[N-1]
289 * is the 'right-most').
290 *
291 * Value = 0
292 * For number of bits in Buffer[]
293 * If (left-most bit of Buffer[] is 1)
294 * Value ^= left-most 32 bits of Key[]
295 * Key[] << 1
296 * Buffer[] << 1
297 *
298 * The code below is provided for convenience where an operating system
299 * does not already provide an implementation.
300 */
301 #ifdef XEN_NETIF_DEFINE_TOEPLITZ
306 {
311 /* Pre-load prefix with the first 8 bytes of the key */
315 }
326 }
328 /*
329 * 'prefix' has now been left-shifted by 8, so
330 * OR in the next byte.
331 */
333 keyi++;
334 }
336 /* The valid part of the hash is in the upper 32 bits. */
338 }
341 /*
342 * Control requests (struct xen_netif_ctrl_request)
343 * ================================================
344 *
345 * All requests have the following format:
346 *
347 * 0 1 2 3 4 5 6 7 octet
348 * +-----+-----+-----+-----+-----+-----+-----+-----+
349 * | id | type | data[0] |
350 * +-----+-----+-----+-----+-----+-----+-----+-----+
351 * | data[1] | data[2] |
352 * +-----+-----+-----+-----+-----------------------+
353 *
354 * id: the request identifier, echoed in response.
355 * type: the type of request (see below)
356 * data[]: any data associated with the request (determined by type)
357 */
363 #define XEN_NETIF_CTRL_TYPE_INVALID 0
364 #define XEN_NETIF_CTRL_TYPE_GET_HASH_FLAGS 1
365 #define XEN_NETIF_CTRL_TYPE_SET_HASH_FLAGS 2
366 #define XEN_NETIF_CTRL_TYPE_SET_HASH_KEY 3
367 #define XEN_NETIF_CTRL_TYPE_GET_HASH_MAPPING_SIZE 4
368 #define XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE 5
369 #define XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING 6
370 #define XEN_NETIF_CTRL_TYPE_SET_HASH_ALGORITHM 7
371 #define XEN_NETIF_CTRL_TYPE_GET_GREF_MAPPING_SIZE 8
372 #define XEN_NETIF_CTRL_TYPE_ADD_GREF_MAPPING 9
373 #define XEN_NETIF_CTRL_TYPE_DEL_GREF_MAPPING 10
376 };
378 /*
379 * Control responses (struct xen_netif_ctrl_response)
380 * ==================================================
381 *
382 * All responses have the following format:
383 *
384 * 0 1 2 3 4 5 6 7 octet
385 * +-----+-----+-----+-----+-----+-----+-----+-----+
386 * | id | type | status |
387 * +-----+-----+-----+-----+-----+-----+-----+-----+
388 * | data |
389 * +-----+-----+-----+-----+
390 *
391 * id: the corresponding request identifier
392 * type: the type of the corresponding request
393 * status: the status of request processing
394 * data: any data associated with the response (determined by type and
395 * status)
396 */
403 #define XEN_NETIF_CTRL_STATUS_SUCCESS 0
404 #define XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED 1
405 #define XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER 2
406 #define XEN_NETIF_CTRL_STATUS_BUFFER_OVERFLOW 3
409 };
411 /*
412 * Static Grants (struct xen_netif_gref)
413 * =====================================
414 *
415 * A frontend may provide a fixed set of grant references to be mapped on
416 * the backend. The message of type XEN_NETIF_CTRL_TYPE_ADD_GREF_MAPPING
417 * prior its usage in the command ring allows for creation of these mappings.
418 * The backend will maintain a fixed amount of these mappings.
419 *
420 * XEN_NETIF_CTRL_TYPE_GET_GREF_MAPPING_SIZE lets a frontend query how many
421 * of these mappings can be kept.
422 *
423 * Each entry in the XEN_NETIF_CTRL_TYPE_{ADD,DEL}_GREF_MAPPING input table has
424 * the following format:
425 *
426 * 0 1 2 3 4 5 6 7 octet
427 * +-----+-----+-----+-----+-----+-----+-----+-----+
428 * | grant ref | flags | status |
429 * +-----+-----+-----+-----+-----+-----+-----+-----+
430 *
431 * grant ref: grant reference (IN)
432 * flags: flags describing the control operation (IN)
433 * status: XEN_NETIF_CTRL_STATUS_* (OUT)
434 *
435 * 'status' is an output parameter which does not require to be set to zero
436 * prior to its usage in the corresponding control messages.
437 */
440 grant_ref_t ref;
443 #define _XEN_NETIF_CTRLF_GREF_readonly 0
444 #define XEN_NETIF_CTRLF_GREF_readonly (1U<<_XEN_NETIF_CTRLF_GREF_readonly)
447 };
449 /*
450 * Control messages
451 * ================
452 *
453 * XEN_NETIF_CTRL_TYPE_SET_HASH_ALGORITHM
454 * --------------------------------------
455 *
456 * This is sent by the frontend to set the desired hash algorithm.
457 *
458 * Request:
459 *
460 * type = XEN_NETIF_CTRL_TYPE_SET_HASH_ALGORITHM
461 * data[0] = a XEN_NETIF_CTRL_HASH_ALGORITHM_* value
462 * data[1] = 0
463 * data[2] = 0
464 *
465 * Response:
466 *
467 * status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not
468 * supported
469 * XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER - The algorithm is not
470 * supported
471 * XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
472 *
473 * NOTE: Setting data[0] to XEN_NETIF_CTRL_HASH_ALGORITHM_NONE disables
474 * hashing and the backend is free to choose how it steers packets
475 * to queues (which is the default behaviour).
476 *
477 * XEN_NETIF_CTRL_TYPE_GET_HASH_FLAGS
478 * ----------------------------------
479 *
480 * This is sent by the frontend to query the types of hash supported by
481 * the backend.
482 *
483 * Request:
484 *
485 * type = XEN_NETIF_CTRL_TYPE_GET_HASH_FLAGS
486 * data[0] = 0
487 * data[1] = 0
488 * data[2] = 0
489 *
490 * Response:
491 *
492 * status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not supported
493 * XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
494 * data = supported hash types (if operation was successful)
495 *
496 * NOTE: A valid hash algorithm must be selected before this operation can
497 * succeed.
498 *
499 * XEN_NETIF_CTRL_TYPE_SET_HASH_FLAGS
500 * ----------------------------------
501 *
502 * This is sent by the frontend to set the types of hash that the backend
503 * should calculate. (See above for hash type definitions).
504 * Note that the 'maximal' type of hash should always be chosen. For
505 * example, if the frontend sets both IPV4 and IPV4_TCP hash types then
506 * the latter hash type should be calculated for any TCP packet and the
507 * former only calculated for non-TCP packets.
508 *
509 * Request:
510 *
511 * type = XEN_NETIF_CTRL_TYPE_SET_HASH_FLAGS
512 * data[0] = bitwise OR of XEN_NETIF_CTRL_HASH_TYPE_* values
513 * data[1] = 0
514 * data[2] = 0
515 *
516 * Response:
517 *
518 * status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not
519 * supported
520 * XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER - One or more flag
521 * value is invalid or
522 * unsupported
523 * XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
524 * data = 0
525 *
526 * NOTE: A valid hash algorithm must be selected before this operation can
527 * succeed.
528 * Also, setting data[0] to zero disables hashing and the backend
529 * is free to choose how it steers packets to queues.
530 *
531 * XEN_NETIF_CTRL_TYPE_SET_HASH_KEY
532 * --------------------------------
533 *
534 * This is sent by the frontend to set the key of the hash if the algorithm
535 * requires it. (See hash algorithms above).
536 *
537 * Request:
538 *
539 * type = XEN_NETIF_CTRL_TYPE_SET_HASH_KEY
540 * data[0] = grant reference of page containing the key (assumed to
541 * start at beginning of grant)
542 * data[1] = size of key in octets
543 * data[2] = 0
544 *
545 * Response:
546 *
547 * status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not
548 * supported
549 * XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER - Key size is invalid
550 * XEN_NETIF_CTRL_STATUS_BUFFER_OVERFLOW - Key size is larger
551 * than the backend
552 * supports
553 * XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
554 * data = 0
555 *
556 * NOTE: Any key octets not specified are assumed to be zero (the key
557 * is assumed to be empty by default) and specifying a new key
558 * invalidates any previous key, hence specifying a key size of
559 * zero will clear the key (which ensures that the calculated hash
560 * will always be zero).
561 * The maximum size of key is algorithm and backend specific, but
562 * is also limited by the single grant reference.
563 * The grant reference may be read-only and must remain valid until
564 * the response has been processed.
565 *
566 * XEN_NETIF_CTRL_TYPE_GET_HASH_MAPPING_SIZE
567 * -----------------------------------------
568 *
569 * This is sent by the frontend to query the maximum size of mapping
570 * table supported by the backend. The size is specified in terms of
571 * table entries.
572 *
573 * Request:
574 *
575 * type = XEN_NETIF_CTRL_TYPE_GET_HASH_MAPPING_SIZE
576 * data[0] = 0
577 * data[1] = 0
578 * data[2] = 0
579 *
580 * Response:
581 *
582 * status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not supported
583 * XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
584 * data = maximum number of entries allowed in the mapping table
585 * (if operation was successful) or zero if a mapping table is
586 * not supported (i.e. hash mapping is done only by modular
587 * arithmetic).
588 *
589 * XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE
590 * -------------------------------------
591 *
592 * This is sent by the frontend to set the actual size of the mapping
593 * table to be used by the backend. The size is specified in terms of
594 * table entries.
595 * Any previous table is invalidated by this message and any new table
596 * is assumed to be zero filled.
597 *
598 * Request:
599 *
600 * type = XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE
601 * data[0] = number of entries in mapping table
602 * data[1] = 0
603 * data[2] = 0
604 *
605 * Response:
606 *
607 * status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not
608 * supported
609 * XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER - Table size is invalid
610 * XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
611 * data = 0
612 *
613 * NOTE: Setting data[0] to 0 means that hash mapping should be done
614 * using modular arithmetic.
615 *
616 * XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING
617 * ------------------------------------
618 *
619 * This is sent by the frontend to set the content of the table mapping
620 * hash value to queue number. The backend should calculate the hash from
621 * the packet header, use it as an index into the table (modulo the size
622 * of the table) and then steer the packet to the queue number found at
623 * that index.
624 *
625 * Request:
626 *
627 * type = XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING
628 * data[0] = grant reference of page containing the mapping (sub-)table
629 * (assumed to start at beginning of grant)
630 * data[1] = size of (sub-)table in entries
631 * data[2] = offset, in entries, of sub-table within overall table
632 *
633 * Response:
634 *
635 * status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not
636 * supported
637 * XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER - Table size or content
638 * is invalid
639 * XEN_NETIF_CTRL_STATUS_BUFFER_OVERFLOW - Table size is larger
640 * than the backend
641 * supports
642 * XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
643 * data = 0
644 *
645 * NOTE: The overall table has the following format:
646 *
647 * 0 1 2 3 4 5 6 7 octet
648 * +-----+-----+-----+-----+-----+-----+-----+-----+
649 * | mapping[0] | mapping[1] |
650 * +-----+-----+-----+-----+-----+-----+-----+-----+
651 * | . |
652 * | . |
653 * | . |
654 * +-----+-----+-----+-----+-----+-----+-----+-----+
655 * | mapping[N-2] | mapping[N-1] |
656 * +-----+-----+-----+-----+-----+-----+-----+-----+
657 *
658 * where N is specified by a XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE
659 * message and each mapping must specifies a queue between 0 and
660 * "multi-queue-num-queues" (see above).
661 * The backend may support a mapping table larger than can be
662 * mapped by a single grant reference. Thus sub-tables within a
663 * larger table can be individually set by sending multiple messages
664 * with differing offset values. Specifying a new sub-table does not
665 * invalidate any table data outside that range.
666 * The grant reference may be read-only and must remain valid until
667 * the response has been processed.
668 *
669 * XEN_NETIF_CTRL_TYPE_GET_GREF_MAPPING_SIZE
670 * -----------------------------------------
671 *
672 * This is sent by the frontend to fetch the number of grefs that can be kept
673 * mapped in the backend.
674 *
675 * Request:
676 *
677 * type = XEN_NETIF_CTRL_TYPE_GET_GREF_MAPPING_SIZE
678 * data[0] = queue index (assumed 0 for single queue)
679 * data[1] = 0
680 * data[2] = 0
681 *
682 * Response:
683 *
684 * status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not
685 * supported
686 * XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER - The queue index is
687 * out of range
688 * XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
689 * data = maximum number of entries allowed in the gref mapping table
690 * (if operation was successful) or zero if it is not supported.
691 *
692 * XEN_NETIF_CTRL_TYPE_ADD_GREF_MAPPING
693 * ------------------------------------
694 *
695 * This is sent by the frontend for backend to map a list of grant
696 * references.
697 *
698 * Request:
699 *
700 * type = XEN_NETIF_CTRL_TYPE_ADD_GREF_MAPPING
701 * data[0] = queue index
702 * data[1] = grant reference of page containing the mapping list
703 * (r/w and assumed to start at beginning of page)
704 * data[2] = size of list in entries
705 *
706 * Response:
707 *
708 * status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not
709 * supported
710 * XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER - Operation failed
711 * XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
712 *
713 * NOTE: Each entry in the input table has the format outlined
714 * in struct xen_netif_gref.
715 * Contrary to XEN_NETIF_CTRL_TYPE_DEL_GREF_MAPPING, the struct
716 * xen_netif_gref 'status' field is not used and therefore the response
717 * 'status' determines the success of this operation. In case of
718 * failure none of grants mappings get added in the backend.
719 *
720 * XEN_NETIF_CTRL_TYPE_DEL_GREF_MAPPING
721 * ------------------------------------
722 *
723 * This is sent by the frontend for backend to unmap a list of grant
724 * references.
725 *
726 * Request:
727 *
728 * type = XEN_NETIF_CTRL_TYPE_DEL_GREF_MAPPING
729 * data[0] = queue index
730 * data[1] = grant reference of page containing the mapping list
731 * (r/w and assumed to start at beginning of page)
732 * data[2] = size of list in entries
733 *
734 * Response:
735 *
736 * status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not
737 * supported
738 * XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER - Operation failed
739 * XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
740 * data = number of entries that were unmapped
741 *
742 * NOTE: Each entry in the input table has the format outlined in struct
743 * xen_netif_gref.
744 * The struct xen_netif_gref 'status' field determines if the entry
745 * was successfully removed.
746 * The entries used are only the ones representing grant references that
747 * were previously the subject of a XEN_NETIF_CTRL_TYPE_ADD_GREF_MAPPING
748 * operation. Any other entries will have their status set to
749 * XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER upon completion.
750 */
756 /*
757 * Guest transmit
758 * ==============
759 *
760 * This is the 'wire' format for transmit (frontend -> backend) packets:
761 *
762 * Fragment 1: netif_tx_request_t - flags = NETTXF_*
763 * size = total packet size
764 * [Extra 1: netif_extra_info_t] - (only if fragment 1 flags include
765 * NETTXF_extra_info)
766 * ...
767 * [Extra N: netif_extra_info_t] - (only if extra N-1 flags include
768 * XEN_NETIF_EXTRA_MORE)
769 * ...
770 * Fragment N: netif_tx_request_t - (only if fragment N-1 flags include
771 * NETTXF_more_data - flags on preceding
772 * extras are not relevant here)
773 * flags = 0
774 * size = fragment size
775 *
776 * NOTE:
777 *
778 * This format slightly is different from that used for receive
779 * (backend -> frontend) packets. Specifically, in a multi-fragment
780 * packet the actual size of fragment 1 can only be determined by
781 * subtracting the sizes of fragments 2..N from the total packet size.
782 *
783 * Ring slot size is 12 octets, however not all request/response
784 * structs use the full size.
785 *
786 * tx request data (netif_tx_request_t)
787 * ------------------------------------
788 *
789 * 0 1 2 3 4 5 6 7 octet
790 * +-----+-----+-----+-----+-----+-----+-----+-----+
791 * | grant ref | offset | flags |
792 * +-----+-----+-----+-----+-----+-----+-----+-----+
793 * | id | size |
794 * +-----+-----+-----+-----+
795 *
796 * grant ref: Reference to buffer page.
797 * offset: Offset within buffer page.
798 * flags: NETTXF_*.
799 * id: request identifier, echoed in response.
800 * size: packet size in bytes.
801 *
802 * tx response (netif_tx_response_t)
803 * ---------------------------------
804 *
805 * 0 1 2 3 4 5 6 7 octet
806 * +-----+-----+-----+-----+-----+-----+-----+-----+
807 * | id | status | unused |
808 * +-----+-----+-----+-----+-----+-----+-----+-----+
809 * | unused |
810 * +-----+-----+-----+-----+
811 *
812 * id: reflects id in transmit request
813 * status: NETIF_RSP_*
814 *
815 * Guest receive
816 * =============
817 *
818 * This is the 'wire' format for receive (backend -> frontend) packets:
819 *
820 * Fragment 1: netif_rx_request_t - flags = NETRXF_*
821 * size = fragment size
822 * [Extra 1: netif_extra_info_t] - (only if fragment 1 flags include
823 * NETRXF_extra_info)
824 * ...
825 * [Extra N: netif_extra_info_t] - (only if extra N-1 flags include
826 * XEN_NETIF_EXTRA_MORE)
827 * ...
828 * Fragment N: netif_rx_request_t - (only if fragment N-1 flags include
829 * NETRXF_more_data - flags on preceding
830 * extras are not relevant here)
831 * flags = 0
832 * size = fragment size
833 *
834 * NOTE:
835 *
836 * This format slightly is different from that used for transmit
837 * (frontend -> backend) packets. Specifically, in a multi-fragment
838 * packet the size of the packet can only be determined by summing the
839 * sizes of fragments 1..N.
840 *
841 * Ring slot size is 8 octets.
842 *
843 * rx request (netif_rx_request_t)
844 * -------------------------------
845 *
846 * 0 1 2 3 4 5 6 7 octet
847 * +-----+-----+-----+-----+-----+-----+-----+-----+
848 * | id | pad | gref |
849 * +-----+-----+-----+-----+-----+-----+-----+-----+
850 *
851 * id: request identifier, echoed in response.
852 * gref: reference to incoming granted frame.
853 *
854 * rx response (netif_rx_response_t)
855 * ---------------------------------
856 *
857 * 0 1 2 3 4 5 6 7 octet
858 * +-----+-----+-----+-----+-----+-----+-----+-----+
859 * | id | offset | flags | status |
860 * +-----+-----+-----+-----+-----+-----+-----+-----+
861 *
862 * id: reflects id in receive request
863 * offset: offset in page of start of received packet
864 * flags: NETRXF_*
865 * status: -ve: NETIF_RSP_*; +ve: Rx'ed pkt size.
866 *
867 * NOTE: Historically, to support GSO on the frontend receive side, Linux
868 * netfront does not make use of the rx response id (because, as
869 * described below, extra info structures overlay the id field).
870 * Instead it assumes that responses always appear in the same ring
871 * slot as their corresponding request. Thus, to maintain
872 * compatibility, backends must make sure this is the case.
873 *
874 * Extra Info
875 * ==========
876 *
877 * Can be present if initial request or response has NET{T,R}XF_extra_info,
878 * or previous extra request has XEN_NETIF_EXTRA_MORE.
879 *
880 * The struct therefore needs to fit into either a tx or rx slot and
881 * is therefore limited to 8 octets.
882 *
883 * NOTE: Because extra info data overlays the usual request/response
884 * structures, there is no id information in the opposite direction.
885 * So, if an extra info overlays an rx response the frontend can
886 * assume that it is in the same ring slot as the request that was
887 * consumed to make the slot available, and the backend must ensure
888 * this assumption is true.
889 *
890 * extra info (netif_extra_info_t)
891 * -------------------------------
892 *
893 * General format:
894 *
895 * 0 1 2 3 4 5 6 7 octet
896 * +-----+-----+-----+-----+-----+-----+-----+-----+
897 * |type |flags| type specific data |
898 * +-----+-----+-----+-----+-----+-----+-----+-----+
899 * | padding for tx |
900 * +-----+-----+-----+-----+
901 *
902 * type: XEN_NETIF_EXTRA_TYPE_*
903 * flags: XEN_NETIF_EXTRA_FLAG_*
904 * padding for tx: present only in the tx case due to 8 octet limit
905 * from rx case. Not shown in type specific entries
906 * below.
907 *
908 * XEN_NETIF_EXTRA_TYPE_GSO:
909 *
910 * 0 1 2 3 4 5 6 7 octet
911 * +-----+-----+-----+-----+-----+-----+-----+-----+
912 * |type |flags| size |type | pad | features |
913 * +-----+-----+-----+-----+-----+-----+-----+-----+
914 *
915 * type: Must be XEN_NETIF_EXTRA_TYPE_GSO
916 * flags: XEN_NETIF_EXTRA_FLAG_*
917 * size: Maximum payload size of each segment. For example,
918 * for TCP this is just the path MSS.
919 * type: XEN_NETIF_GSO_TYPE_*: This determines the protocol of
920 * the packet and any extra features required to segment the
921 * packet properly.
922 * features: EN_NETIF_GSO_FEAT_*: This specifies any extra GSO
923 * features required to process this packet, such as ECN
924 * support for TCPv4.
925 *
926 * XEN_NETIF_EXTRA_TYPE_MCAST_{ADD,DEL}:
927 *
928 * 0 1 2 3 4 5 6 7 octet
929 * +-----+-----+-----+-----+-----+-----+-----+-----+
930 * |type |flags| addr |
931 * +-----+-----+-----+-----+-----+-----+-----+-----+
932 *
933 * type: Must be XEN_NETIF_EXTRA_TYPE_MCAST_{ADD,DEL}
934 * flags: XEN_NETIF_EXTRA_FLAG_*
935 * addr: address to add/remove
936 *
937 * XEN_NETIF_EXTRA_TYPE_HASH:
938 *
939 * A backend that supports teoplitz hashing is assumed to accept
940 * this type of extra info in transmit packets.
941 * A frontend that enables hashing is assumed to accept
942 * this type of extra info in receive packets.
943 *
944 * 0 1 2 3 4 5 6 7 octet
945 * +-----+-----+-----+-----+-----+-----+-----+-----+
946 * |type |flags|htype| alg |LSB ---- value ---- MSB|
947 * +-----+-----+-----+-----+-----+-----+-----+-----+
948 *
949 * type: Must be XEN_NETIF_EXTRA_TYPE_HASH
950 * flags: XEN_NETIF_EXTRA_FLAG_*
951 * htype: Hash type (one of _XEN_NETIF_CTRL_HASH_TYPE_* - see above)
952 * alg: The algorithm used to calculate the hash (one of
953 * XEN_NETIF_CTRL_HASH_TYPE_ALGORITHM_* - see above)
954 * value: Hash value
955 */
957 /* Protocol checksum field is blank in the packet (hardware offload)? */
958 #define _NETTXF_csum_blank (0)
959 #define NETTXF_csum_blank (1U<<_NETTXF_csum_blank)
961 /* Packet data has been validated against protocol checksum. */
962 #define _NETTXF_data_validated (1)
963 #define NETTXF_data_validated (1U<<_NETTXF_data_validated)
965 /* Packet continues in the next request descriptor. */
966 #define _NETTXF_more_data (2)
967 #define NETTXF_more_data (1U<<_NETTXF_more_data)
969 /* Packet to be followed by extra descriptor(s). */
970 #define _NETTXF_extra_info (3)
971 #define NETTXF_extra_info (1U<<_NETTXF_extra_info)
973 #define XEN_NETIF_MAX_TX_SIZE 0xFFFF
975 grant_ref_t gref;
980 };
983 /* Types of netif_extra_info descriptors. */
989 #define XEN_NETIF_EXTRA_TYPE_MAX (5)
991 /* netif_extra_info_t flags. */
992 #define _XEN_NETIF_EXTRA_FLAG_MORE (0)
993 #define XEN_NETIF_EXTRA_FLAG_MORE (1U<<_XEN_NETIF_EXTRA_FLAG_MORE)
995 /* GSO types */
996 #define XEN_NETIF_GSO_TYPE_NONE (0)
997 #define XEN_NETIF_GSO_TYPE_TCPV4 (1)
998 #define XEN_NETIF_GSO_TYPE_TCPV6 (2)
1000 /*
1001 * This structure needs to fit within both netif_tx_request_t and
1002 * netif_rx_response_t for compatibility.
1003 */
1024 };
1030 };
1036 grant_ref_t gref;
1037 };
1040 /* Packet data has been validated against protocol checksum. */
1041 #define _NETRXF_data_validated (0)
1042 #define NETRXF_data_validated (1U<<_NETRXF_data_validated)
1044 /* Protocol checksum field is blank in the packet (hardware offload)? */
1045 #define _NETRXF_csum_blank (1)
1046 #define NETRXF_csum_blank (1U<<_NETRXF_csum_blank)
1048 /* Packet continues in the next request descriptor. */
1049 #define _NETRXF_more_data (2)
1050 #define NETRXF_more_data (1U<<_NETRXF_more_data)
1052 /* Packet to be followed by extra descriptor(s). */
1053 #define _NETRXF_extra_info (3)
1054 #define NETRXF_extra_info (1U<<_NETRXF_extra_info)
1056 /* Packet has GSO prefix. Deprecated but included for compatibility */
1057 #define _NETRXF_gso_prefix (4)
1058 #define NETRXF_gso_prefix (1U<<_NETRXF_gso_prefix)
1065 };
1068 /*
1069 * Generate netif ring structures and types.
1070 */
1075 #define NETIF_RSP_DROPPED -2
1076 #define NETIF_RSP_ERROR -1
1077 #define NETIF_RSP_OKAY 0
1078 /* No response: used for auxiliary requests (e.g., netif_extra_info_t). */
1079 #define NETIF_RSP_NULL 1
1081 #endif
1083 /*
1084 * Local variables:
1085 * mode: C
1086 * c-file-style: "BSD"
1087 * c-basic-offset: 4
1088 * tab-width: 4
1089 * indent-tabs-mode: nil
1090 * End:
1091 */