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1 /******************************************************************************
2 * xen_netif.h
3 *
4 * Unified network-device I/O interface for Xen guest OSes.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to
8 * deal in the Software without restriction, including without limitation the
9 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
10 * sell copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
22 * DEALINGS IN THE SOFTWARE.
23 *
24 * Copyright (c) 2003-2004, Keir Fraser
25 */
27 #ifndef __XEN_PUBLIC_IO_XEN_NETIF_H__
28 #define __XEN_PUBLIC_IO_XEN_NETIF_H__
33 /*
34 * Older implementation of Xen network frontend / backend has an
35 * implicit dependency on the MAX_SKB_FRAGS as the maximum number of
36 * ring slots a skb can use. Netfront / netback may not work as
37 * expected when frontend and backend have different MAX_SKB_FRAGS.
38 *
39 * A better approach is to add mechanism for netfront / netback to
40 * negotiate this value. However we cannot fix all possible
41 * frontends, so we need to define a value which states the minimum
42 * slots backend must support.
43 *
44 * The minimum value derives from older Linux kernel's MAX_SKB_FRAGS
45 * (18), which is proved to work with most frontends. Any new backend
46 * which doesn't negotiate with frontend should expect frontend to
47 * send a valid packet using slots up to this value.
48 */
49 #define XEN_NETIF_NR_SLOTS_MIN 18
51 /*
52 * Notifications after enqueuing any type of message should be conditional on
53 * the appropriate req_event or rsp_event field in the shared ring.
54 * If the client sends notification for rx requests then it should specify
55 * feature 'feature-rx-notify' via xenbus. Otherwise the backend will assume
56 * that it cannot safely queue packets (as it may not be kicked to send them).
57 */
59 /*
60 * "feature-split-event-channels" is introduced to separate guest TX
61 * and RX notification. Backend either doesn't support this feature or
62 * advertises it via xenstore as 0 (disabled) or 1 (enabled).
63 *
64 * To make use of this feature, frontend should allocate two event
65 * channels for TX and RX, advertise them to backend as
66 * "event-channel-tx" and "event-channel-rx" respectively. If frontend
67 * doesn't want to use this feature, it just writes "event-channel"
68 * node as before.
69 */
71 /*
72 * Multiple transmit and receive queues:
73 * If supported, the backend will write the key "multi-queue-max-queues" to
74 * the directory for that vif, and set its value to the maximum supported
75 * number of queues.
76 * Frontends that are aware of this feature and wish to use it can write the
77 * key "multi-queue-num-queues", set to the number they wish to use, which
78 * must be greater than zero, and no more than the value reported by the backend
79 * in "multi-queue-max-queues".
80 *
81 * Queues replicate the shared rings and event channels.
82 * "feature-split-event-channels" may optionally be used when using
83 * multiple queues, but is not mandatory.
84 *
85 * Each queue consists of one shared ring pair, i.e. there must be the same
86 * number of tx and rx rings.
87 *
88 * For frontends requesting just one queue, the usual event-channel and
89 * ring-ref keys are written as before, simplifying the backend processing
90 * to avoid distinguishing between a frontend that doesn't understand the
91 * multi-queue feature, and one that does, but requested only one queue.
92 *
93 * Frontends requesting two or more queues must not write the toplevel
94 * event-channel (or event-channel-{tx,rx}) and {tx,rx}-ring-ref keys,
95 * instead writing those keys under sub-keys having the name "queue-N" where
96 * N is the integer ID of the queue for which those keys belong. Queues
97 * are indexed from zero. For example, a frontend with two queues and split
98 * event channels must write the following set of queue-related keys:
99 *
100 * /local/domain/1/device/vif/0/multi-queue-num-queues = "2"
101 * /local/domain/1/device/vif/0/queue-0 = ""
102 * /local/domain/1/device/vif/0/queue-0/tx-ring-ref = "<ring-ref-tx0>"
103 * /local/domain/1/device/vif/0/queue-0/rx-ring-ref = "<ring-ref-rx0>"
104 * /local/domain/1/device/vif/0/queue-0/event-channel-tx = "<evtchn-tx0>"
105 * /local/domain/1/device/vif/0/queue-0/event-channel-rx = "<evtchn-rx0>"
106 * /local/domain/1/device/vif/0/queue-1 = ""
107 * /local/domain/1/device/vif/0/queue-1/tx-ring-ref = "<ring-ref-tx1>"
108 * /local/domain/1/device/vif/0/queue-1/rx-ring-ref = "<ring-ref-rx1"
109 * /local/domain/1/device/vif/0/queue-1/event-channel-tx = "<evtchn-tx1>"
110 * /local/domain/1/device/vif/0/queue-1/event-channel-rx = "<evtchn-rx1>"
111 *
112 * If there is any inconsistency in the XenStore data, the backend may
113 * choose not to connect any queues, instead treating the request as an
114 * error. This includes scenarios where more (or fewer) queues were
115 * requested than the frontend provided details for.
116 *
117 * Mapping of packets to queues is considered to be a function of the
118 * transmitting system (backend or frontend) and is not negotiated
119 * between the two. Guests are free to transmit packets on any queue
120 * they choose, provided it has been set up correctly. Guests must be
121 * prepared to receive packets on any queue they have requested be set up.
122 */
124 /*
125 * "feature-no-csum-offload" should be used to turn IPv4 TCP/UDP checksum
126 * offload off or on. If it is missing then the feature is assumed to be on.
127 * "feature-ipv6-csum-offload" should be used to turn IPv6 TCP/UDP checksum
128 * offload on or off. If it is missing then the feature is assumed to be off.
129 */
131 /*
132 * "feature-gso-tcpv4" and "feature-gso-tcpv6" advertise the capability to
133 * handle large TCP packets (in IPv4 or IPv6 form respectively). Neither
134 * frontends nor backends are assumed to be capable unless the flags are
135 * present.
136 */
138 /*
139 * "feature-multicast-control" and "feature-dynamic-multicast-control"
140 * advertise the capability to filter ethernet multicast packets in the
141 * backend. If the frontend wishes to take advantage of this feature then
142 * it may set "request-multicast-control". If the backend only advertises
143 * "feature-multicast-control" then "request-multicast-control" must be set
144 * before the frontend moves into the connected state. The backend will
145 * sample the value on this state transition and any subsequent change in
146 * value will have no effect. However, if the backend also advertises
147 * "feature-dynamic-multicast-control" then "request-multicast-control"
148 * may be set by the frontend at any time. In this case, the backend will
149 * watch the value and re-sample on watch events.
150 *
151 * If the sampled value of "request-multicast-control" is set then the
152 * backend transmit side should no longer flood multicast packets to the
153 * frontend, it should instead drop any multicast packet that does not
154 * match in a filter list.
155 * The list is amended by the frontend by sending dummy transmit requests
156 * containing XEN_NETIF_EXTRA_TYPE_MCAST_{ADD,DEL} extra-info fragments as
157 * specified below.
158 * Note that the filter list may be amended even if the sampled value of
159 * "request-multicast-control" is not set, however the filter should only
160 * be applied if it is set.
161 */
163 /*
164 * "xdp-headroom" is used to request that extra space is added
165 * for XDP processing. The value is measured in bytes and passed by
166 * the frontend to be consistent between both ends.
167 * If the value is greater than zero that means that
168 * an RX response is going to be passed to an XDP program for processing.
169 * XEN_NETIF_MAX_XDP_HEADROOM defines the maximum headroom offset in bytes
170 *
171 * "feature-xdp-headroom" is set to "1" by the netback side like other features
172 * so a guest can check if an XDP program can be processed.
173 */
174 #define XEN_NETIF_MAX_XDP_HEADROOM 0x7FFF
176 /*
177 * Control ring
178 * ============
179 *
180 * Some features, such as hashing (detailed below), require a
181 * significant amount of out-of-band data to be passed from frontend to
182 * backend. Use of xenstore is not suitable for large quantities of data
183 * because of quota limitations and so a dedicated 'control ring' is used.
184 * The ability of the backend to use a control ring is advertised by
185 * setting:
186 *
187 * /local/domain/X/backend/<domid>/<vif>/feature-ctrl-ring = "1"
188 *
189 * The frontend provides a control ring to the backend by setting:
190 *
191 * /local/domain/<domid>/device/vif/<vif>/ctrl-ring-ref = <gref>
192 * /local/domain/<domid>/device/vif/<vif>/event-channel-ctrl = <port>
193 *
194 * where <gref> is the grant reference of the shared page used to
195 * implement the control ring and <port> is an event channel to be used
196 * as a mailbox interrupt. These keys must be set before the frontend
197 * moves into the connected state.
198 *
199 * The control ring uses a fixed request/response message size and is
200 * balanced (i.e. one request to one response), so operationally it is much
201 * the same as a transmit or receive ring.
202 * Note that there is no requirement that responses are issued in the same
203 * order as requests.
204 */
206 /*
207 * Hash types
208 * ==========
209 *
210 * For the purposes of the definitions below, 'Packet[]' is an array of
211 * octets containing an IP packet without options, 'Array[X..Y]' means a
212 * sub-array of 'Array' containing bytes X thru Y inclusive, and '+' is
213 * used to indicate concatenation of arrays.
214 */
216 /*
217 * A hash calculated over an IP version 4 header as follows:
218 *
219 * Buffer[0..8] = Packet[12..15] (source address) +
220 * Packet[16..19] (destination address)
221 *
222 * Result = Hash(Buffer, 8)
223 */
224 #define _XEN_NETIF_CTRL_HASH_TYPE_IPV4 0
225 #define XEN_NETIF_CTRL_HASH_TYPE_IPV4 \
226 (1 << _XEN_NETIF_CTRL_HASH_TYPE_IPV4)
228 /*
229 * A hash calculated over an IP version 4 header and TCP header as
230 * follows:
231 *
232 * Buffer[0..12] = Packet[12..15] (source address) +
233 * Packet[16..19] (destination address) +
234 * Packet[20..21] (source port) +
235 * Packet[22..23] (destination port)
236 *
237 * Result = Hash(Buffer, 12)
238 */
239 #define _XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP 1
240 #define XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP \
241 (1 << _XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP)
243 /*
244 * A hash calculated over an IP version 6 header as follows:
245 *
246 * Buffer[0..32] = Packet[8..23] (source address ) +
247 * Packet[24..39] (destination address)
248 *
249 * Result = Hash(Buffer, 32)
250 */
251 #define _XEN_NETIF_CTRL_HASH_TYPE_IPV6 2
252 #define XEN_NETIF_CTRL_HASH_TYPE_IPV6 \
253 (1 << _XEN_NETIF_CTRL_HASH_TYPE_IPV6)
255 /*
256 * A hash calculated over an IP version 6 header and TCP header as
257 * follows:
258 *
259 * Buffer[0..36] = Packet[8..23] (source address) +
260 * Packet[24..39] (destination address) +
261 * Packet[40..41] (source port) +
262 * Packet[42..43] (destination port)
263 *
264 * Result = Hash(Buffer, 36)
265 */
266 #define _XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP 3
267 #define XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP \
268 (1 << _XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP)
270 /*
271 * Hash algorithms
272 * ===============
273 */
275 #define XEN_NETIF_CTRL_HASH_ALGORITHM_NONE 0
277 /*
278 * Toeplitz hash:
279 */
281 #define XEN_NETIF_CTRL_HASH_ALGORITHM_TOEPLITZ 1
283 /*
284 * This algorithm uses a 'key' as well as the data buffer itself.
285 * (Buffer[] and Key[] are treated as shift-registers where the MSB of
286 * Buffer/Key[0] is considered 'left-most' and the LSB of Buffer/Key[N-1]
287 * is the 'right-most').
288 *
289 * Value = 0
290 * For number of bits in Buffer[]
291 * If (left-most bit of Buffer[] is 1)
292 * Value ^= left-most 32 bits of Key[]
293 * Key[] << 1
294 * Buffer[] << 1
295 *
296 * The code below is provided for convenience where an operating system
297 * does not already provide an implementation.
298 */
299 #ifdef XEN_NETIF_DEFINE_TOEPLITZ
303 {
308 /* Pre-load prefix with the first 8 bytes of the key */
312 }
323 }
325 /*
326 * 'prefix' has now been left-shifted by 8, so
327 * OR in the next byte.
328 */
330 keyi++;
331 }
333 /* The valid part of the hash is in the upper 32 bits. */
335 }
338 /*
339 * Control requests (struct xen_netif_ctrl_request)
340 * ================================================
341 *
342 * All requests have the following format:
343 *
344 * 0 1 2 3 4 5 6 7 octet
345 * +-----+-----+-----+-----+-----+-----+-----+-----+
346 * | id | type | data[0] |
347 * +-----+-----+-----+-----+-----+-----+-----+-----+
348 * | data[1] | data[2] |
349 * +-----+-----+-----+-----+-----------------------+
350 *
351 * id: the request identifier, echoed in response.
352 * type: the type of request (see below)
353 * data[]: any data associated with the request (determined by type)
354 */
360 #define XEN_NETIF_CTRL_TYPE_INVALID 0
361 #define XEN_NETIF_CTRL_TYPE_GET_HASH_FLAGS 1
362 #define XEN_NETIF_CTRL_TYPE_SET_HASH_FLAGS 2
363 #define XEN_NETIF_CTRL_TYPE_SET_HASH_KEY 3
364 #define XEN_NETIF_CTRL_TYPE_GET_HASH_MAPPING_SIZE 4
365 #define XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE 5
366 #define XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING 6
367 #define XEN_NETIF_CTRL_TYPE_SET_HASH_ALGORITHM 7
370 };
372 /*
373 * Control responses (struct xen_netif_ctrl_response)
374 * ==================================================
375 *
376 * All responses have the following format:
377 *
378 * 0 1 2 3 4 5 6 7 octet
379 * +-----+-----+-----+-----+-----+-----+-----+-----+
380 * | id | type | status |
381 * +-----+-----+-----+-----+-----+-----+-----+-----+
382 * | data |
383 * +-----+-----+-----+-----+
384 *
385 * id: the corresponding request identifier
386 * type: the type of the corresponding request
387 * status: the status of request processing
388 * data: any data associated with the response (determined by type and
389 * status)
390 */
397 #define XEN_NETIF_CTRL_STATUS_SUCCESS 0
398 #define XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED 1
399 #define XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER 2
400 #define XEN_NETIF_CTRL_STATUS_BUFFER_OVERFLOW 3
403 };
405 /*
406 * Control messages
407 * ================
408 *
409 * XEN_NETIF_CTRL_TYPE_SET_HASH_ALGORITHM
410 * --------------------------------------
411 *
412 * This is sent by the frontend to set the desired hash algorithm.
413 *
414 * Request:
415 *
416 * type = XEN_NETIF_CTRL_TYPE_SET_HASH_ALGORITHM
417 * data[0] = a XEN_NETIF_CTRL_HASH_ALGORITHM_* value
418 * data[1] = 0
419 * data[2] = 0
420 *
421 * Response:
422 *
423 * status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not
424 * supported
425 * XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER - The algorithm is not
426 * supported
427 * XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
428 *
429 * NOTE: Setting data[0] to XEN_NETIF_CTRL_HASH_ALGORITHM_NONE disables
430 * hashing and the backend is free to choose how it steers packets
431 * to queues (which is the default behaviour).
432 *
433 * XEN_NETIF_CTRL_TYPE_GET_HASH_FLAGS
434 * ----------------------------------
435 *
436 * This is sent by the frontend to query the types of hash supported by
437 * the backend.
438 *
439 * Request:
440 *
441 * type = XEN_NETIF_CTRL_TYPE_GET_HASH_FLAGS
442 * data[0] = 0
443 * data[1] = 0
444 * data[2] = 0
445 *
446 * Response:
447 *
448 * status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not supported
449 * XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
450 * data = supported hash types (if operation was successful)
451 *
452 * NOTE: A valid hash algorithm must be selected before this operation can
453 * succeed.
454 *
455 * XEN_NETIF_CTRL_TYPE_SET_HASH_FLAGS
456 * ----------------------------------
457 *
458 * This is sent by the frontend to set the types of hash that the backend
459 * should calculate. (See above for hash type definitions).
460 * Note that the 'maximal' type of hash should always be chosen. For
461 * example, if the frontend sets both IPV4 and IPV4_TCP hash types then
462 * the latter hash type should be calculated for any TCP packet and the
463 * former only calculated for non-TCP packets.
464 *
465 * Request:
466 *
467 * type = XEN_NETIF_CTRL_TYPE_SET_HASH_FLAGS
468 * data[0] = bitwise OR of XEN_NETIF_CTRL_HASH_TYPE_* values
469 * data[1] = 0
470 * data[2] = 0
471 *
472 * Response:
473 *
474 * status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not
475 * supported
476 * XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER - One or more flag
477 * value is invalid or
478 * unsupported
479 * XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
480 * data = 0
481 *
482 * NOTE: A valid hash algorithm must be selected before this operation can
483 * succeed.
484 * Also, setting data[0] to zero disables hashing and the backend
485 * is free to choose how it steers packets to queues.
486 *
487 * XEN_NETIF_CTRL_TYPE_SET_HASH_KEY
488 * --------------------------------
489 *
490 * This is sent by the frontend to set the key of the hash if the algorithm
491 * requires it. (See hash algorithms above).
492 *
493 * Request:
494 *
495 * type = XEN_NETIF_CTRL_TYPE_SET_HASH_KEY
496 * data[0] = grant reference of page containing the key (assumed to
497 * start at beginning of grant)
498 * data[1] = size of key in octets
499 * data[2] = 0
500 *
501 * Response:
502 *
503 * status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not
504 * supported
505 * XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER - Key size is invalid
506 * XEN_NETIF_CTRL_STATUS_BUFFER_OVERFLOW - Key size is larger
507 * than the backend
508 * supports
509 * XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
510 * data = 0
511 *
512 * NOTE: Any key octets not specified are assumed to be zero (the key
513 * is assumed to be empty by default) and specifying a new key
514 * invalidates any previous key, hence specifying a key size of
515 * zero will clear the key (which ensures that the calculated hash
516 * will always be zero).
517 * The maximum size of key is algorithm and backend specific, but
518 * is also limited by the single grant reference.
519 * The grant reference may be read-only and must remain valid until
520 * the response has been processed.
521 *
522 * XEN_NETIF_CTRL_TYPE_GET_HASH_MAPPING_SIZE
523 * -----------------------------------------
524 *
525 * This is sent by the frontend to query the maximum size of mapping
526 * table supported by the backend. The size is specified in terms of
527 * table entries.
528 *
529 * Request:
530 *
531 * type = XEN_NETIF_CTRL_TYPE_GET_HASH_MAPPING_SIZE
532 * data[0] = 0
533 * data[1] = 0
534 * data[2] = 0
535 *
536 * Response:
537 *
538 * status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not supported
539 * XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
540 * data = maximum number of entries allowed in the mapping table
541 * (if operation was successful) or zero if a mapping table is
542 * not supported (i.e. hash mapping is done only by modular
543 * arithmetic).
544 *
545 * XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE
546 * -------------------------------------
547 *
548 * This is sent by the frontend to set the actual size of the mapping
549 * table to be used by the backend. The size is specified in terms of
550 * table entries.
551 * Any previous table is invalidated by this message and any new table
552 * is assumed to be zero filled.
553 *
554 * Request:
555 *
556 * type = XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE
557 * data[0] = number of entries in mapping table
558 * data[1] = 0
559 * data[2] = 0
560 *
561 * Response:
562 *
563 * status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not
564 * supported
565 * XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER - Table size is invalid
566 * XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
567 * data = 0
568 *
569 * NOTE: Setting data[0] to 0 means that hash mapping should be done
570 * using modular arithmetic.
571 *
572 * XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING
573 * ------------------------------------
574 *
575 * This is sent by the frontend to set the content of the table mapping
576 * hash value to queue number. The backend should calculate the hash from
577 * the packet header, use it as an index into the table (modulo the size
578 * of the table) and then steer the packet to the queue number found at
579 * that index.
580 *
581 * Request:
582 *
583 * type = XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING
584 * data[0] = grant reference of page containing the mapping (sub-)table
585 * (assumed to start at beginning of grant)
586 * data[1] = size of (sub-)table in entries
587 * data[2] = offset, in entries, of sub-table within overall table
588 *
589 * Response:
590 *
591 * status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not
592 * supported
593 * XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER - Table size or content
594 * is invalid
595 * XEN_NETIF_CTRL_STATUS_BUFFER_OVERFLOW - Table size is larger
596 * than the backend
597 * supports
598 * XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
599 * data = 0
600 *
601 * NOTE: The overall table has the following format:
602 *
603 * 0 1 2 3 4 5 6 7 octet
604 * +-----+-----+-----+-----+-----+-----+-----+-----+
605 * | mapping[0] | mapping[1] |
606 * +-----+-----+-----+-----+-----+-----+-----+-----+
607 * | . |
608 * | . |
609 * | . |
610 * +-----+-----+-----+-----+-----+-----+-----+-----+
611 * | mapping[N-2] | mapping[N-1] |
612 * +-----+-----+-----+-----+-----+-----+-----+-----+
613 *
614 * where N is specified by a XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE
615 * message and each mapping must specifies a queue between 0 and
616 * "multi-queue-num-queues" (see above).
617 * The backend may support a mapping table larger than can be
618 * mapped by a single grant reference. Thus sub-tables within a
619 * larger table can be individually set by sending multiple messages
620 * with differing offset values. Specifying a new sub-table does not
621 * invalidate any table data outside that range.
622 * The grant reference may be read-only and must remain valid until
623 * the response has been processed.
624 */
630 /*
631 * Guest transmit
632 * ==============
633 *
634 * This is the 'wire' format for transmit (frontend -> backend) packets:
635 *
636 * Fragment 1: xen_netif_tx_request_t - flags = XEN_NETTXF_*
637 * size = total packet size
638 * [Extra 1: xen_netif_extra_info_t] - (only if fragment 1 flags include
639 * XEN_NETTXF_extra_info)
640 * ...
641 * [Extra N: xen_netif_extra_info_t] - (only if extra N-1 flags include
642 * XEN_NETIF_EXTRA_MORE)
643 * ...
644 * Fragment N: xen_netif_tx_request_t - (only if fragment N-1 flags include
645 * XEN_NETTXF_more_data - flags on preceding
646 * extras are not relevant here)
647 * flags = 0
648 * size = fragment size
649 *
650 * NOTE:
651 *
652 * This format slightly is different from that used for receive
653 * (backend -> frontend) packets. Specifically, in a multi-fragment
654 * packet the actual size of fragment 1 can only be determined by
655 * subtracting the sizes of fragments 2..N from the total packet size.
656 *
657 * Ring slot size is 12 octets, however not all request/response
658 * structs use the full size.
659 *
660 * tx request data (xen_netif_tx_request_t)
661 * ------------------------------------
662 *
663 * 0 1 2 3 4 5 6 7 octet
664 * +-----+-----+-----+-----+-----+-----+-----+-----+
665 * | grant ref | offset | flags |
666 * +-----+-----+-----+-----+-----+-----+-----+-----+
667 * | id | size |
668 * +-----+-----+-----+-----+
669 *
670 * grant ref: Reference to buffer page.
671 * offset: Offset within buffer page.
672 * flags: XEN_NETTXF_*.
673 * id: request identifier, echoed in response.
674 * size: packet size in bytes.
675 *
676 * tx response (xen_netif_tx_response_t)
677 * ---------------------------------
678 *
679 * 0 1 2 3 4 5 6 7 octet
680 * +-----+-----+-----+-----+-----+-----+-----+-----+
681 * | id | status | unused |
682 * +-----+-----+-----+-----+-----+-----+-----+-----+
683 * | unused |
684 * +-----+-----+-----+-----+
685 *
686 * id: reflects id in transmit request
687 * status: XEN_NETIF_RSP_*
688 *
689 * Guest receive
690 * =============
691 *
692 * This is the 'wire' format for receive (backend -> frontend) packets:
693 *
694 * Fragment 1: xen_netif_rx_request_t - flags = XEN_NETRXF_*
695 * size = fragment size
696 * [Extra 1: xen_netif_extra_info_t] - (only if fragment 1 flags include
697 * XEN_NETRXF_extra_info)
698 * ...
699 * [Extra N: xen_netif_extra_info_t] - (only if extra N-1 flags include
700 * XEN_NETIF_EXTRA_MORE)
701 * ...
702 * Fragment N: xen_netif_rx_request_t - (only if fragment N-1 flags include
703 * XEN_NETRXF_more_data - flags on preceding
704 * extras are not relevant here)
705 * flags = 0
706 * size = fragment size
707 *
708 * NOTE:
709 *
710 * This format slightly is different from that used for transmit
711 * (frontend -> backend) packets. Specifically, in a multi-fragment
712 * packet the size of the packet can only be determined by summing the
713 * sizes of fragments 1..N.
714 *
715 * Ring slot size is 8 octets.
716 *
717 * rx request (xen_netif_rx_request_t)
718 * -------------------------------
719 *
720 * 0 1 2 3 4 5 6 7 octet
721 * +-----+-----+-----+-----+-----+-----+-----+-----+
722 * | id | pad | gref |
723 * +-----+-----+-----+-----+-----+-----+-----+-----+
724 *
725 * id: request identifier, echoed in response.
726 * gref: reference to incoming granted frame.
727 *
728 * rx response (xen_netif_rx_response_t)
729 * ---------------------------------
730 *
731 * 0 1 2 3 4 5 6 7 octet
732 * +-----+-----+-----+-----+-----+-----+-----+-----+
733 * | id | offset | flags | status |
734 * +-----+-----+-----+-----+-----+-----+-----+-----+
735 *
736 * id: reflects id in receive request
737 * offset: offset in page of start of received packet
738 * flags: XEN_NETRXF_*
739 * status: -ve: XEN_NETIF_RSP_*; +ve: Rx'ed pkt size.
740 *
741 * NOTE: Historically, to support GSO on the frontend receive side, Linux
742 * netfront does not make use of the rx response id (because, as
743 * described below, extra info structures overlay the id field).
744 * Instead it assumes that responses always appear in the same ring
745 * slot as their corresponding request. Thus, to maintain
746 * compatibility, backends must make sure this is the case.
747 *
748 * Extra Info
749 * ==========
750 *
751 * Can be present if initial request or response has NET{T,R}XF_extra_info,
752 * or previous extra request has XEN_NETIF_EXTRA_MORE.
753 *
754 * The struct therefore needs to fit into either a tx or rx slot and
755 * is therefore limited to 8 octets.
756 *
757 * NOTE: Because extra info data overlays the usual request/response
758 * structures, there is no id information in the opposite direction.
759 * So, if an extra info overlays an rx response the frontend can
760 * assume that it is in the same ring slot as the request that was
761 * consumed to make the slot available, and the backend must ensure
762 * this assumption is true.
763 *
764 * extra info (xen_netif_extra_info_t)
765 * -------------------------------
766 *
767 * General format:
768 *
769 * 0 1 2 3 4 5 6 7 octet
770 * +-----+-----+-----+-----+-----+-----+-----+-----+
771 * |type |flags| type specific data |
772 * +-----+-----+-----+-----+-----+-----+-----+-----+
773 * | padding for tx |
774 * +-----+-----+-----+-----+
775 *
776 * type: XEN_NETIF_EXTRA_TYPE_*
777 * flags: XEN_NETIF_EXTRA_FLAG_*
778 * padding for tx: present only in the tx case due to 8 octet limit
779 * from rx case. Not shown in type specific entries
780 * below.
781 *
782 * XEN_NETIF_EXTRA_TYPE_GSO:
783 *
784 * 0 1 2 3 4 5 6 7 octet
785 * +-----+-----+-----+-----+-----+-----+-----+-----+
786 * |type |flags| size |type | pad | features |
787 * +-----+-----+-----+-----+-----+-----+-----+-----+
788 *
789 * type: Must be XEN_NETIF_EXTRA_TYPE_GSO
790 * flags: XEN_NETIF_EXTRA_FLAG_*
791 * size: Maximum payload size of each segment. For example,
792 * for TCP this is just the path MSS.
793 * type: XEN_NETIF_GSO_TYPE_*: This determines the protocol of
794 * the packet and any extra features required to segment the
795 * packet properly.
796 * features: EN_XEN_NETIF_GSO_FEAT_*: This specifies any extra GSO
797 * features required to process this packet, such as ECN
798 * support for TCPv4.
799 *
800 * XEN_NETIF_EXTRA_TYPE_MCAST_{ADD,DEL}:
801 *
802 * 0 1 2 3 4 5 6 7 octet
803 * +-----+-----+-----+-----+-----+-----+-----+-----+
804 * |type |flags| addr |
805 * +-----+-----+-----+-----+-----+-----+-----+-----+
806 *
807 * type: Must be XEN_NETIF_EXTRA_TYPE_MCAST_{ADD,DEL}
808 * flags: XEN_NETIF_EXTRA_FLAG_*
809 * addr: address to add/remove
810 *
811 * XEN_NETIF_EXTRA_TYPE_HASH:
812 *
813 * A backend that supports teoplitz hashing is assumed to accept
814 * this type of extra info in transmit packets.
815 * A frontend that enables hashing is assumed to accept
816 * this type of extra info in receive packets.
817 *
818 * 0 1 2 3 4 5 6 7 octet
819 * +-----+-----+-----+-----+-----+-----+-----+-----+
820 * |type |flags|htype| alg |LSB ---- value ---- MSB|
821 * +-----+-----+-----+-----+-----+-----+-----+-----+
822 *
823 * type: Must be XEN_NETIF_EXTRA_TYPE_HASH
824 * flags: XEN_NETIF_EXTRA_FLAG_*
825 * htype: Hash type (one of _XEN_NETIF_CTRL_HASH_TYPE_* - see above)
826 * alg: The algorithm used to calculate the hash (one of
827 * XEN_NETIF_CTRL_HASH_TYPE_ALGORITHM_* - see above)
828 * value: Hash value
829 */
831 /* Protocol checksum field is blank in the packet (hardware offload)? */
832 #define _XEN_NETTXF_csum_blank (0)
833 #define XEN_NETTXF_csum_blank (1U<<_XEN_NETTXF_csum_blank)
835 /* Packet data has been validated against protocol checksum. */
836 #define _XEN_NETTXF_data_validated (1)
837 #define XEN_NETTXF_data_validated (1U<<_XEN_NETTXF_data_validated)
839 /* Packet continues in the next request descriptor. */
840 #define _XEN_NETTXF_more_data (2)
841 #define XEN_NETTXF_more_data (1U<<_XEN_NETTXF_more_data)
843 /* Packet to be followed by extra descriptor(s). */
844 #define _XEN_NETTXF_extra_info (3)
845 #define XEN_NETTXF_extra_info (1U<<_XEN_NETTXF_extra_info)
847 #define XEN_NETIF_MAX_TX_SIZE 0xFFFF
849 grant_ref_t gref;
854 };
856 /* Types of xen_netif_extra_info descriptors. */
863 #define XEN_NETIF_EXTRA_TYPE_MAX (6)
865 /* xen_netif_extra_info_t flags. */
866 #define _XEN_NETIF_EXTRA_FLAG_MORE (0)
867 #define XEN_NETIF_EXTRA_FLAG_MORE (1U<<_XEN_NETIF_EXTRA_FLAG_MORE)
869 /* GSO types */
870 #define XEN_NETIF_GSO_TYPE_NONE (0)
871 #define XEN_NETIF_GSO_TYPE_TCPV4 (1)
872 #define XEN_NETIF_GSO_TYPE_TCPV6 (2)
874 /*
875 * This structure needs to fit within both xen_netif_tx_request_t and
876 * xen_netif_rx_response_t for compatibility.
877 */
902 };
907 };
912 grant_ref_t gref;
913 };
915 /* Packet data has been validated against protocol checksum. */
916 #define _XEN_NETRXF_data_validated (0)
917 #define XEN_NETRXF_data_validated (1U<<_XEN_NETRXF_data_validated)
919 /* Protocol checksum field is blank in the packet (hardware offload)? */
920 #define _XEN_NETRXF_csum_blank (1)
921 #define XEN_NETRXF_csum_blank (1U<<_XEN_NETRXF_csum_blank)
923 /* Packet continues in the next request descriptor. */
924 #define _XEN_NETRXF_more_data (2)
925 #define XEN_NETRXF_more_data (1U<<_XEN_NETRXF_more_data)
927 /* Packet to be followed by extra descriptor(s). */
928 #define _XEN_NETRXF_extra_info (3)
929 #define XEN_NETRXF_extra_info (1U<<_XEN_NETRXF_extra_info)
931 /* Packet has GSO prefix. Deprecated but included for compatibility */
932 #define _XEN_NETRXF_gso_prefix (4)
933 #define XEN_NETRXF_gso_prefix (1U<<_XEN_NETRXF_gso_prefix)
940 };
942 /*
943 * Generate xen_netif ring structures and types.
944 */
951 #define XEN_NETIF_RSP_DROPPED -2
952 #define XEN_NETIF_RSP_ERROR -1
953 #define XEN_NETIF_RSP_OKAY 0
954 /* No response: used for auxiliary requests (e.g., xen_netif_extra_info_t). */
955 #define XEN_NETIF_RSP_NULL 1
957 #endif