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1// SPDX-License-Identifier: GPL-2.0-only
2/* Copyright (c) 2013-2018, 2021, The Linux Foundation. All rights reserved.
3 *
4 * RMNET Data MAP protocol
5 */
6
7#include <linux/netdevice.h>
8#include <linux/ip.h>
9#include <linux/ipv6.h>
10#include <net/ip6_checksum.h>
11#include <linux/bitfield.h>
12#include "rmnet_config.h"
13#include "rmnet_map.h"
14#include "rmnet_private.h"
15#include "rmnet_vnd.h"
16
17#define RMNET_MAP_DEAGGR_SPACING 64
18#define RMNET_MAP_DEAGGR_HEADROOM (RMNET_MAP_DEAGGR_SPACING / 2)
19
20static __sum16 *rmnet_map_get_csum_field(unsigned char protocol,
21 const void *txporthdr)
22{
23 if (protocol == IPPROTO_TCP)
24 return &((struct tcphdr *)txporthdr)->check;
25
26 if (protocol == IPPROTO_UDP)
27 return &((struct udphdr *)txporthdr)->check;
28
29 return NULL;
30}
31
32static int
33rmnet_map_ipv4_dl_csum_trailer(struct sk_buff *skb,
34 struct rmnet_map_dl_csum_trailer *csum_trailer,
35 struct rmnet_priv *priv)
36{
37 struct iphdr *ip4h = (struct iphdr *)skb->data;
38 void *txporthdr = skb->data + ip4h->ihl * 4;
39 __sum16 *csum_field, pseudo_csum;
40 __sum16 ip_payload_csum;
41
42 /* Computing the checksum over just the IPv4 header--including its
43 * checksum field--should yield 0. If it doesn't, the IP header
44 * is bad, so return an error and let the IP layer drop it.
45 */
46 if (ip_fast_csum(ip4h, ip4h->ihl)) {
47 priv->stats.csum_ip4_header_bad++;
48 return -EINVAL;
49 }
50
51 /* We don't support checksum offload on IPv4 fragments */
52 if (ip_is_fragment(ip4h)) {
53 priv->stats.csum_fragmented_pkt++;
54 return -EOPNOTSUPP;
55 }
56
57 /* Checksum offload is only supported for UDP and TCP protocols */
58 csum_field = rmnet_map_get_csum_field(ip4h->protocol, txporthdr);
59 if (!csum_field) {
60 priv->stats.csum_err_invalid_transport++;
61 return -EPROTONOSUPPORT;
62 }
63
64 /* RFC 768: UDP checksum is optional for IPv4, and is 0 if unused */
65 if (!*csum_field && ip4h->protocol == IPPROTO_UDP) {
66 priv->stats.csum_skipped++;
67 return 0;
68 }
69
70 /* The checksum value in the trailer is computed over the entire
71 * IP packet, including the IP header and payload. To derive the
72 * transport checksum from this, we first subract the contribution
73 * of the IP header from the trailer checksum. We then add the
74 * checksum computed over the pseudo header.
75 *
76 * We verified above that the IP header contributes zero to the
77 * trailer checksum. Therefore the checksum in the trailer is
78 * just the checksum computed over the IP payload.
79
80 * If the IP payload arrives intact, adding the pseudo header
81 * checksum to the IP payload checksum will yield 0xffff (negative
82 * zero). This means the trailer checksum and the pseudo checksum
83 * are additive inverses of each other. Put another way, the
84 * message passes the checksum test if the trailer checksum value
85 * is the negated pseudo header checksum.
86 *
87 * Knowing this, we don't even need to examine the transport
88 * header checksum value; it is already accounted for in the
89 * checksum value found in the trailer.
90 */
91 ip_payload_csum = csum_trailer->csum_value;
92
93 pseudo_csum = csum_tcpudp_magic(ip4h->saddr, ip4h->daddr,
94 ntohs(ip4h->tot_len) - ip4h->ihl * 4,
95 ip4h->protocol, 0);
96
97 /* The cast is required to ensure only the low 16 bits are examined */
98 if (ip_payload_csum != (__sum16)~pseudo_csum) {
99 priv->stats.csum_validation_failed++;
100 return -EINVAL;
101 }
102
103 priv->stats.csum_ok++;
104 return 0;
105}
106
107#if IS_ENABLED(CONFIG_IPV6)
108static int
109rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb,
110 struct rmnet_map_dl_csum_trailer *csum_trailer,
111 struct rmnet_priv *priv)
112{
113 struct ipv6hdr *ip6h = (struct ipv6hdr *)skb->data;
114 void *txporthdr = skb->data + sizeof(*ip6h);
115 __sum16 *csum_field, pseudo_csum;
116 __sum16 ip6_payload_csum;
117 __be16 ip_header_csum;
118
119 /* Checksum offload is only supported for UDP and TCP protocols;
120 * the packet cannot include any IPv6 extension headers
121 */
122 csum_field = rmnet_map_get_csum_field(ip6h->nexthdr, txporthdr);
123 if (!csum_field) {
124 priv->stats.csum_err_invalid_transport++;
125 return -EPROTONOSUPPORT;
126 }
127
128 /* The checksum value in the trailer is computed over the entire
129 * IP packet, including the IP header and payload. To derive the
130 * transport checksum from this, we first subract the contribution
131 * of the IP header from the trailer checksum. We then add the
132 * checksum computed over the pseudo header.
133 */
134 ip_header_csum = (__force __be16)ip_fast_csum(ip6h, sizeof(*ip6h) / 4);
135 ip6_payload_csum = csum16_sub(csum_trailer->csum_value, ip_header_csum);
136
137 pseudo_csum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
138 ntohs(ip6h->payload_len),
139 ip6h->nexthdr, 0);
140
141 /* It's sufficient to compare the IP payload checksum with the
142 * negated pseudo checksum to determine whether the packet
143 * checksum was good. (See further explanation in comments
144 * in rmnet_map_ipv4_dl_csum_trailer()).
145 *
146 * The cast is required to ensure only the low 16 bits are
147 * examined.
148 */
149 if (ip6_payload_csum != (__sum16)~pseudo_csum) {
150 priv->stats.csum_validation_failed++;
151 return -EINVAL;
152 }
153
154 priv->stats.csum_ok++;
155 return 0;
156}
157#else
158static int
159rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb,
160 struct rmnet_map_dl_csum_trailer *csum_trailer,
161 struct rmnet_priv *priv)
162{
163 return 0;
164}
165#endif
166
167static void rmnet_map_complement_ipv4_txporthdr_csum_field(struct iphdr *ip4h)
168{
169 void *txphdr;
170 u16 *csum;
171
172 txphdr = (void *)ip4h + ip4h->ihl * 4;
173
174 if (ip4h->protocol == IPPROTO_TCP || ip4h->protocol == IPPROTO_UDP) {
175 csum = (u16 *)rmnet_map_get_csum_field(ip4h->protocol, txphdr);
176 *csum = ~(*csum);
177 }
178}
179
180static void
181rmnet_map_ipv4_ul_csum_header(struct iphdr *iphdr,
182 struct rmnet_map_ul_csum_header *ul_header,
183 struct sk_buff *skb)
184{
185 u16 val;
186
187 val = MAP_CSUM_UL_ENABLED_FLAG;
188 if (iphdr->protocol == IPPROTO_UDP)
189 val |= MAP_CSUM_UL_UDP_FLAG;
190 val |= skb->csum_offset & MAP_CSUM_UL_OFFSET_MASK;
191
192 ul_header->csum_start_offset = htons(skb_network_header_len(skb));
193 ul_header->csum_info = htons(val);
194
195 skb->ip_summed = CHECKSUM_NONE;
196
197 rmnet_map_complement_ipv4_txporthdr_csum_field(iphdr);
198}
199
200#if IS_ENABLED(CONFIG_IPV6)
201static void
202rmnet_map_complement_ipv6_txporthdr_csum_field(struct ipv6hdr *ip6h)
203{
204 void *txphdr;
205 u16 *csum;
206
207 txphdr = ip6h + 1;
208
209 if (ip6h->nexthdr == IPPROTO_TCP || ip6h->nexthdr == IPPROTO_UDP) {
210 csum = (u16 *)rmnet_map_get_csum_field(ip6h->nexthdr, txphdr);
211 *csum = ~(*csum);
212 }
213}
214
215static void
216rmnet_map_ipv6_ul_csum_header(struct ipv6hdr *ipv6hdr,
217 struct rmnet_map_ul_csum_header *ul_header,
218 struct sk_buff *skb)
219{
220 u16 val;
221
222 val = MAP_CSUM_UL_ENABLED_FLAG;
223 if (ipv6hdr->nexthdr == IPPROTO_UDP)
224 val |= MAP_CSUM_UL_UDP_FLAG;
225 val |= skb->csum_offset & MAP_CSUM_UL_OFFSET_MASK;
226
227 ul_header->csum_start_offset = htons(skb_network_header_len(skb));
228 ul_header->csum_info = htons(val);
229
230 skb->ip_summed = CHECKSUM_NONE;
231
232 rmnet_map_complement_ipv6_txporthdr_csum_field(ipv6hdr);
233}
234#else
235static void
236rmnet_map_ipv6_ul_csum_header(void *ip6hdr,
237 struct rmnet_map_ul_csum_header *ul_header,
238 struct sk_buff *skb)
239{
240}
241#endif
242
243static void rmnet_map_v5_checksum_uplink_packet(struct sk_buff *skb,
244 struct rmnet_port *port,
245 struct net_device *orig_dev)
246{
247 struct rmnet_priv *priv = netdev_priv(orig_dev);
248 struct rmnet_map_v5_csum_header *ul_header;
249
250 ul_header = skb_push(skb, sizeof(*ul_header));
251 memset(ul_header, 0, sizeof(*ul_header));
252 ul_header->header_info = u8_encode_bits(RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD,
253 MAPV5_HDRINFO_HDR_TYPE_FMASK);
254
255 if (skb->ip_summed == CHECKSUM_PARTIAL) {
256 void *iph = ip_hdr(skb);
257 __sum16 *check;
258 void *trans;
259 u8 proto;
260
261 if (skb->protocol == htons(ETH_P_IP)) {
262 u16 ip_len = ((struct iphdr *)iph)->ihl * 4;
263
264 proto = ((struct iphdr *)iph)->protocol;
265 trans = iph + ip_len;
266 } else if (IS_ENABLED(CONFIG_IPV6) &&
267 skb->protocol == htons(ETH_P_IPV6)) {
268 u16 ip_len = sizeof(struct ipv6hdr);
269
270 proto = ((struct ipv6hdr *)iph)->nexthdr;
271 trans = iph + ip_len;
272 } else {
273 priv->stats.csum_err_invalid_ip_version++;
274 goto sw_csum;
275 }
276
277 check = rmnet_map_get_csum_field(proto, trans);
278 if (check) {
279 skb->ip_summed = CHECKSUM_NONE;
280 /* Ask for checksum offloading */
281 ul_header->csum_info |= MAPV5_CSUMINFO_VALID_FLAG;
282 priv->stats.csum_hw++;
283 return;
284 }
285 }
286
287sw_csum:
288 priv->stats.csum_sw++;
289}
290
291/* Adds MAP header to front of skb->data
292 * Padding is calculated and set appropriately in MAP header. Mux ID is
293 * initialized to 0.
294 */
295struct rmnet_map_header *rmnet_map_add_map_header(struct sk_buff *skb,
296 int hdrlen,
297 struct rmnet_port *port,
298 int pad)
299{
300 struct rmnet_map_header *map_header;
301 u32 padding, map_datalen;
302
303 map_datalen = skb->len - hdrlen;
304 map_header = (struct rmnet_map_header *)
305 skb_push(skb, sizeof(struct rmnet_map_header));
306 memset(map_header, 0, sizeof(struct rmnet_map_header));
307
308 /* Set next_hdr bit for csum offload packets */
309 if (port->data_format & RMNET_FLAGS_EGRESS_MAP_CKSUMV5)
310 map_header->flags |= MAP_NEXT_HEADER_FLAG;
311
312 if (pad == RMNET_MAP_NO_PAD_BYTES) {
313 map_header->pkt_len = htons(map_datalen);
314 return map_header;
315 }
316
317 BUILD_BUG_ON(MAP_PAD_LEN_MASK < 3);
318 padding = ALIGN(map_datalen, 4) - map_datalen;
319
320 if (padding == 0)
321 goto done;
322
323 if (skb_tailroom(skb) < padding)
324 return NULL;
325
326 skb_put_zero(skb, padding);
327
328done:
329 map_header->pkt_len = htons(map_datalen + padding);
330 /* This is a data packet, so the CMD bit is 0 */
331 map_header->flags = padding & MAP_PAD_LEN_MASK;
332
333 return map_header;
334}
335
336/* Deaggregates a single packet
337 * A whole new buffer is allocated for each portion of an aggregated frame.
338 * Caller should keep calling deaggregate() on the source skb until 0 is
339 * returned, indicating that there are no more packets to deaggregate. Caller
340 * is responsible for freeing the original skb.
341 */
342struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb,
343 struct rmnet_port *port)
344{
345 struct rmnet_map_v5_csum_header *next_hdr = NULL;
346 struct rmnet_map_header *maph;
347 void *data = skb->data;
348 struct sk_buff *skbn;
349 u8 nexthdr_type;
350 u32 packet_len;
351
352 if (skb->len == 0)
353 return NULL;
354
355 maph = (struct rmnet_map_header *)skb->data;
356 packet_len = ntohs(maph->pkt_len) + sizeof(*maph);
357
358 if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV4) {
359 packet_len += sizeof(struct rmnet_map_dl_csum_trailer);
360 } else if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV5) {
361 if (!(maph->flags & MAP_CMD_FLAG)) {
362 packet_len += sizeof(*next_hdr);
363 if (maph->flags & MAP_NEXT_HEADER_FLAG)
364 next_hdr = data + sizeof(*maph);
365 else
366 /* Mapv5 data pkt without csum hdr is invalid */
367 return NULL;
368 }
369 }
370
371 if (((int)skb->len - (int)packet_len) < 0)
372 return NULL;
373
374 /* Some hardware can send us empty frames. Catch them */
375 if (!maph->pkt_len)
376 return NULL;
377
378 if (next_hdr) {
379 nexthdr_type = u8_get_bits(next_hdr->header_info,
380 MAPV5_HDRINFO_HDR_TYPE_FMASK);
381 if (nexthdr_type != RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD)
382 return NULL;
383 }
384
385 skbn = alloc_skb(packet_len + RMNET_MAP_DEAGGR_SPACING, GFP_ATOMIC);
386 if (!skbn)
387 return NULL;
388
389 skb_reserve(skbn, RMNET_MAP_DEAGGR_HEADROOM);
390 skb_put(skbn, packet_len);
391 memcpy(skbn->data, skb->data, packet_len);
392 skb_pull(skb, packet_len);
393
394 return skbn;
395}
396
397/* Validates packet checksums. Function takes a pointer to
398 * the beginning of a buffer which contains the IP payload +
399 * padding + checksum trailer.
400 * Only IPv4 and IPv6 are supported along with TCP & UDP.
401 * Fragmented or tunneled packets are not supported.
402 */
403int rmnet_map_checksum_downlink_packet(struct sk_buff *skb, u16 len)
404{
405 struct rmnet_priv *priv = netdev_priv(skb->dev);
406 struct rmnet_map_dl_csum_trailer *csum_trailer;
407
408 if (unlikely(!(skb->dev->features & NETIF_F_RXCSUM))) {
409 priv->stats.csum_sw++;
410 return -EOPNOTSUPP;
411 }
412
413 csum_trailer = (struct rmnet_map_dl_csum_trailer *)(skb->data + len);
414
415 if (!(csum_trailer->flags & MAP_CSUM_DL_VALID_FLAG)) {
416 priv->stats.csum_valid_unset++;
417 return -EINVAL;
418 }
419
420 if (skb->protocol == htons(ETH_P_IP))
421 return rmnet_map_ipv4_dl_csum_trailer(skb, csum_trailer, priv);
422
423 if (IS_ENABLED(CONFIG_IPV6) && skb->protocol == htons(ETH_P_IPV6))
424 return rmnet_map_ipv6_dl_csum_trailer(skb, csum_trailer, priv);
425
426 priv->stats.csum_err_invalid_ip_version++;
427
428 return -EPROTONOSUPPORT;
429}
430
431static void rmnet_map_v4_checksum_uplink_packet(struct sk_buff *skb,
432 struct net_device *orig_dev)
433{
434 struct rmnet_priv *priv = netdev_priv(orig_dev);
435 struct rmnet_map_ul_csum_header *ul_header;
436 void *iphdr;
437
438 ul_header = (struct rmnet_map_ul_csum_header *)
439 skb_push(skb, sizeof(struct rmnet_map_ul_csum_header));
440
441 if (unlikely(!(orig_dev->features &
442 (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM))))
443 goto sw_csum;
444
445 if (skb->ip_summed != CHECKSUM_PARTIAL)
446 goto sw_csum;
447
448 iphdr = (char *)ul_header +
449 sizeof(struct rmnet_map_ul_csum_header);
450
451 if (skb->protocol == htons(ETH_P_IP)) {
452 rmnet_map_ipv4_ul_csum_header(iphdr, ul_header, skb);
453 priv->stats.csum_hw++;
454 return;
455 }
456
457 if (IS_ENABLED(CONFIG_IPV6) && skb->protocol == htons(ETH_P_IPV6)) {
458 rmnet_map_ipv6_ul_csum_header(iphdr, ul_header, skb);
459 priv->stats.csum_hw++;
460 return;
461 }
462
463 priv->stats.csum_err_invalid_ip_version++;
464
465sw_csum:
466 memset(ul_header, 0, sizeof(*ul_header));
467
468 priv->stats.csum_sw++;
469}
470
471/* Generates UL checksum meta info header for IPv4 and IPv6 over TCP and UDP
472 * packets that are supported for UL checksum offload.
473 */
474void rmnet_map_checksum_uplink_packet(struct sk_buff *skb,
475 struct rmnet_port *port,
476 struct net_device *orig_dev,
477 int csum_type)
478{
479 switch (csum_type) {
480 case RMNET_FLAGS_EGRESS_MAP_CKSUMV4:
481 rmnet_map_v4_checksum_uplink_packet(skb, orig_dev);
482 break;
483 case RMNET_FLAGS_EGRESS_MAP_CKSUMV5:
484 rmnet_map_v5_checksum_uplink_packet(skb, port, orig_dev);
485 break;
486 default:
487 break;
488 }
489}
490
491/* Process a MAPv5 packet header */
492int rmnet_map_process_next_hdr_packet(struct sk_buff *skb,
493 u16 len)
494{
495 struct rmnet_priv *priv = netdev_priv(skb->dev);
496 struct rmnet_map_v5_csum_header *next_hdr;
497 u8 nexthdr_type;
498
499 next_hdr = (struct rmnet_map_v5_csum_header *)(skb->data +
500 sizeof(struct rmnet_map_header));
501
502 nexthdr_type = u8_get_bits(next_hdr->header_info,
503 MAPV5_HDRINFO_HDR_TYPE_FMASK);
504
505 if (nexthdr_type != RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD)
506 return -EINVAL;
507
508 if (unlikely(!(skb->dev->features & NETIF_F_RXCSUM))) {
509 priv->stats.csum_sw++;
510 } else if (next_hdr->csum_info & MAPV5_CSUMINFO_VALID_FLAG) {
511 priv->stats.csum_ok++;
512 skb->ip_summed = CHECKSUM_UNNECESSARY;
513 } else {
514 priv->stats.csum_valid_unset++;
515 }
516
517 /* Pull csum v5 header */
518 skb_pull(skb, sizeof(*next_hdr));
519
520 return 0;
521}
522
523#define RMNET_AGG_BYPASS_TIME_NSEC 10000000L
524
525static void reset_aggr_params(struct rmnet_port *port)
526{
527 port->skbagg_head = NULL;
528 port->agg_count = 0;
529 port->agg_state = 0;
530 memset(&port->agg_time, 0, sizeof(struct timespec64));
531}
532
533static void rmnet_send_skb(struct rmnet_port *port, struct sk_buff *skb)
534{
535 if (skb_needs_linearize(skb, port->dev->features)) {
536 if (unlikely(__skb_linearize(skb))) {
537 struct rmnet_priv *priv;
538
539 priv = netdev_priv(port->rmnet_dev);
540 this_cpu_inc(priv->pcpu_stats->stats.tx_drops);
541 dev_kfree_skb_any(skb);
542 return;
543 }
544 }
545
546 dev_queue_xmit(skb);
547}
548
549static void rmnet_map_flush_tx_packet_work(struct work_struct *work)
550{
551 struct sk_buff *skb = NULL;
552 struct rmnet_port *port;
553
554 port = container_of(work, struct rmnet_port, agg_wq);
555
556 spin_lock_bh(&port->agg_lock);
557 if (likely(port->agg_state == -EINPROGRESS)) {
558 /* Buffer may have already been shipped out */
559 if (likely(port->skbagg_head)) {
560 skb = port->skbagg_head;
561 reset_aggr_params(port);
562 }
563 port->agg_state = 0;
564 }
565
566 spin_unlock_bh(&port->agg_lock);
567 if (skb)
568 rmnet_send_skb(port, skb);
569}
570
571static enum hrtimer_restart rmnet_map_flush_tx_packet_queue(struct hrtimer *t)
572{
573 struct rmnet_port *port;
574
575 port = container_of(t, struct rmnet_port, hrtimer);
576
577 schedule_work(&port->agg_wq);
578
579 return HRTIMER_NORESTART;
580}
581
582unsigned int rmnet_map_tx_aggregate(struct sk_buff *skb, struct rmnet_port *port,
583 struct net_device *orig_dev)
584{
585 struct timespec64 diff, last;
586 unsigned int len = skb->len;
587 struct sk_buff *agg_skb;
588 int size;
589
590 spin_lock_bh(&port->agg_lock);
591 memcpy(&last, &port->agg_last, sizeof(struct timespec64));
592 ktime_get_real_ts64(&port->agg_last);
593
594 if (!port->skbagg_head) {
595 /* Check to see if we should agg first. If the traffic is very
596 * sparse, don't aggregate.
597 */
598new_packet:
599 diff = timespec64_sub(port->agg_last, last);
600 size = port->egress_agg_params.bytes - skb->len;
601
602 if (size < 0) {
603 /* dropped */
604 spin_unlock_bh(&port->agg_lock);
605 return 0;
606 }
607
608 if (diff.tv_sec > 0 || diff.tv_nsec > RMNET_AGG_BYPASS_TIME_NSEC ||
609 size == 0)
610 goto no_aggr;
611
612 port->skbagg_head = skb_copy_expand(skb, 0, size, GFP_ATOMIC);
613 if (!port->skbagg_head)
614 goto no_aggr;
615
616 dev_kfree_skb_any(skb);
617 port->skbagg_head->protocol = htons(ETH_P_MAP);
618 port->agg_count = 1;
619 ktime_get_real_ts64(&port->agg_time);
620 skb_frag_list_init(port->skbagg_head);
621 goto schedule;
622 }
623 diff = timespec64_sub(port->agg_last, port->agg_time);
624 size = port->egress_agg_params.bytes - port->skbagg_head->len;
625
626 if (skb->len > size) {
627 agg_skb = port->skbagg_head;
628 reset_aggr_params(port);
629 spin_unlock_bh(&port->agg_lock);
630 hrtimer_cancel(&port->hrtimer);
631 rmnet_send_skb(port, agg_skb);
632 spin_lock_bh(&port->agg_lock);
633 goto new_packet;
634 }
635
636 if (skb_has_frag_list(port->skbagg_head))
637 port->skbagg_tail->next = skb;
638 else
639 skb_shinfo(port->skbagg_head)->frag_list = skb;
640
641 port->skbagg_head->len += skb->len;
642 port->skbagg_head->data_len += skb->len;
643 port->skbagg_head->truesize += skb->truesize;
644 port->skbagg_tail = skb;
645 port->agg_count++;
646
647 if (diff.tv_sec > 0 || diff.tv_nsec > port->egress_agg_params.time_nsec ||
648 port->agg_count >= port->egress_agg_params.count ||
649 port->skbagg_head->len == port->egress_agg_params.bytes) {
650 agg_skb = port->skbagg_head;
651 reset_aggr_params(port);
652 spin_unlock_bh(&port->agg_lock);
653 hrtimer_cancel(&port->hrtimer);
654 rmnet_send_skb(port, agg_skb);
655 return len;
656 }
657
658schedule:
659 if (!hrtimer_active(&port->hrtimer) && port->agg_state != -EINPROGRESS) {
660 port->agg_state = -EINPROGRESS;
661 hrtimer_start(&port->hrtimer,
662 ns_to_ktime(port->egress_agg_params.time_nsec),
663 HRTIMER_MODE_REL);
664 }
665 spin_unlock_bh(&port->agg_lock);
666
667 return len;
668
669no_aggr:
670 spin_unlock_bh(&port->agg_lock);
671 skb->protocol = htons(ETH_P_MAP);
672 dev_queue_xmit(skb);
673
674 return len;
675}
676
677void rmnet_map_update_ul_agg_config(struct rmnet_port *port, u32 size,
678 u32 count, u32 time)
679{
680 spin_lock_bh(&port->agg_lock);
681 port->egress_agg_params.bytes = size;
682 WRITE_ONCE(port->egress_agg_params.count, count);
683 port->egress_agg_params.time_nsec = time * NSEC_PER_USEC;
684 spin_unlock_bh(&port->agg_lock);
685}
686
687void rmnet_map_tx_aggregate_init(struct rmnet_port *port)
688{
689 hrtimer_init(&port->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
690 port->hrtimer.function = rmnet_map_flush_tx_packet_queue;
691 spin_lock_init(&port->agg_lock);
692 rmnet_map_update_ul_agg_config(port, 4096, 1, 800);
693 INIT_WORK(&port->agg_wq, rmnet_map_flush_tx_packet_work);
694}
695
696void rmnet_map_tx_aggregate_exit(struct rmnet_port *port)
697{
698 hrtimer_cancel(&port->hrtimer);
699 cancel_work_sync(&port->agg_wq);
700
701 spin_lock_bh(&port->agg_lock);
702 if (port->agg_state == -EINPROGRESS) {
703 if (port->skbagg_head) {
704 dev_kfree_skb_any(port->skbagg_head);
705 reset_aggr_params(port);
706 }
707
708 port->agg_state = 0;
709 }
710 spin_unlock_bh(&port->agg_lock);
711}
1// SPDX-License-Identifier: GPL-2.0-only
2/* Copyright (c) 2013-2018, 2021, The Linux Foundation. All rights reserved.
3 *
4 * RMNET Data MAP protocol
5 */
6
7#include <linux/netdevice.h>
8#include <linux/ip.h>
9#include <linux/ipv6.h>
10#include <net/ip6_checksum.h>
11#include <linux/bitfield.h>
12#include "rmnet_config.h"
13#include "rmnet_map.h"
14#include "rmnet_private.h"
15
16#define RMNET_MAP_DEAGGR_SPACING 64
17#define RMNET_MAP_DEAGGR_HEADROOM (RMNET_MAP_DEAGGR_SPACING / 2)
18
19static __sum16 *rmnet_map_get_csum_field(unsigned char protocol,
20 const void *txporthdr)
21{
22 if (protocol == IPPROTO_TCP)
23 return &((struct tcphdr *)txporthdr)->check;
24
25 if (protocol == IPPROTO_UDP)
26 return &((struct udphdr *)txporthdr)->check;
27
28 return NULL;
29}
30
31static int
32rmnet_map_ipv4_dl_csum_trailer(struct sk_buff *skb,
33 struct rmnet_map_dl_csum_trailer *csum_trailer,
34 struct rmnet_priv *priv)
35{
36 struct iphdr *ip4h = (struct iphdr *)skb->data;
37 void *txporthdr = skb->data + ip4h->ihl * 4;
38 __sum16 *csum_field, pseudo_csum;
39 __sum16 ip_payload_csum;
40
41 /* Computing the checksum over just the IPv4 header--including its
42 * checksum field--should yield 0. If it doesn't, the IP header
43 * is bad, so return an error and let the IP layer drop it.
44 */
45 if (ip_fast_csum(ip4h, ip4h->ihl)) {
46 priv->stats.csum_ip4_header_bad++;
47 return -EINVAL;
48 }
49
50 /* We don't support checksum offload on IPv4 fragments */
51 if (ip_is_fragment(ip4h)) {
52 priv->stats.csum_fragmented_pkt++;
53 return -EOPNOTSUPP;
54 }
55
56 /* Checksum offload is only supported for UDP and TCP protocols */
57 csum_field = rmnet_map_get_csum_field(ip4h->protocol, txporthdr);
58 if (!csum_field) {
59 priv->stats.csum_err_invalid_transport++;
60 return -EPROTONOSUPPORT;
61 }
62
63 /* RFC 768: UDP checksum is optional for IPv4, and is 0 if unused */
64 if (!*csum_field && ip4h->protocol == IPPROTO_UDP) {
65 priv->stats.csum_skipped++;
66 return 0;
67 }
68
69 /* The checksum value in the trailer is computed over the entire
70 * IP packet, including the IP header and payload. To derive the
71 * transport checksum from this, we first subract the contribution
72 * of the IP header from the trailer checksum. We then add the
73 * checksum computed over the pseudo header.
74 *
75 * We verified above that the IP header contributes zero to the
76 * trailer checksum. Therefore the checksum in the trailer is
77 * just the checksum computed over the IP payload.
78
79 * If the IP payload arrives intact, adding the pseudo header
80 * checksum to the IP payload checksum will yield 0xffff (negative
81 * zero). This means the trailer checksum and the pseudo checksum
82 * are additive inverses of each other. Put another way, the
83 * message passes the checksum test if the trailer checksum value
84 * is the negated pseudo header checksum.
85 *
86 * Knowing this, we don't even need to examine the transport
87 * header checksum value; it is already accounted for in the
88 * checksum value found in the trailer.
89 */
90 ip_payload_csum = csum_trailer->csum_value;
91
92 pseudo_csum = csum_tcpudp_magic(ip4h->saddr, ip4h->daddr,
93 ntohs(ip4h->tot_len) - ip4h->ihl * 4,
94 ip4h->protocol, 0);
95
96 /* The cast is required to ensure only the low 16 bits are examined */
97 if (ip_payload_csum != (__sum16)~pseudo_csum) {
98 priv->stats.csum_validation_failed++;
99 return -EINVAL;
100 }
101
102 priv->stats.csum_ok++;
103 return 0;
104}
105
106#if IS_ENABLED(CONFIG_IPV6)
107static int
108rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb,
109 struct rmnet_map_dl_csum_trailer *csum_trailer,
110 struct rmnet_priv *priv)
111{
112 struct ipv6hdr *ip6h = (struct ipv6hdr *)skb->data;
113 void *txporthdr = skb->data + sizeof(*ip6h);
114 __sum16 *csum_field, pseudo_csum;
115 __sum16 ip6_payload_csum;
116 __be16 ip_header_csum;
117
118 /* Checksum offload is only supported for UDP and TCP protocols;
119 * the packet cannot include any IPv6 extension headers
120 */
121 csum_field = rmnet_map_get_csum_field(ip6h->nexthdr, txporthdr);
122 if (!csum_field) {
123 priv->stats.csum_err_invalid_transport++;
124 return -EPROTONOSUPPORT;
125 }
126
127 /* The checksum value in the trailer is computed over the entire
128 * IP packet, including the IP header and payload. To derive the
129 * transport checksum from this, we first subract the contribution
130 * of the IP header from the trailer checksum. We then add the
131 * checksum computed over the pseudo header.
132 */
133 ip_header_csum = (__force __be16)ip_fast_csum(ip6h, sizeof(*ip6h) / 4);
134 ip6_payload_csum = csum16_sub(csum_trailer->csum_value, ip_header_csum);
135
136 pseudo_csum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
137 ntohs(ip6h->payload_len),
138 ip6h->nexthdr, 0);
139
140 /* It's sufficient to compare the IP payload checksum with the
141 * negated pseudo checksum to determine whether the packet
142 * checksum was good. (See further explanation in comments
143 * in rmnet_map_ipv4_dl_csum_trailer()).
144 *
145 * The cast is required to ensure only the low 16 bits are
146 * examined.
147 */
148 if (ip6_payload_csum != (__sum16)~pseudo_csum) {
149 priv->stats.csum_validation_failed++;
150 return -EINVAL;
151 }
152
153 priv->stats.csum_ok++;
154 return 0;
155}
156#else
157static int
158rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb,
159 struct rmnet_map_dl_csum_trailer *csum_trailer,
160 struct rmnet_priv *priv)
161{
162 return 0;
163}
164#endif
165
166static void rmnet_map_complement_ipv4_txporthdr_csum_field(struct iphdr *ip4h)
167{
168 void *txphdr;
169 u16 *csum;
170
171 txphdr = (void *)ip4h + ip4h->ihl * 4;
172
173 if (ip4h->protocol == IPPROTO_TCP || ip4h->protocol == IPPROTO_UDP) {
174 csum = (u16 *)rmnet_map_get_csum_field(ip4h->protocol, txphdr);
175 *csum = ~(*csum);
176 }
177}
178
179static void
180rmnet_map_ipv4_ul_csum_header(struct iphdr *iphdr,
181 struct rmnet_map_ul_csum_header *ul_header,
182 struct sk_buff *skb)
183{
184 u16 val;
185
186 val = MAP_CSUM_UL_ENABLED_FLAG;
187 if (iphdr->protocol == IPPROTO_UDP)
188 val |= MAP_CSUM_UL_UDP_FLAG;
189 val |= skb->csum_offset & MAP_CSUM_UL_OFFSET_MASK;
190
191 ul_header->csum_start_offset = htons(skb_network_header_len(skb));
192 ul_header->csum_info = htons(val);
193
194 skb->ip_summed = CHECKSUM_NONE;
195
196 rmnet_map_complement_ipv4_txporthdr_csum_field(iphdr);
197}
198
199#if IS_ENABLED(CONFIG_IPV6)
200static void
201rmnet_map_complement_ipv6_txporthdr_csum_field(struct ipv6hdr *ip6h)
202{
203 void *txphdr;
204 u16 *csum;
205
206 txphdr = ip6h + 1;
207
208 if (ip6h->nexthdr == IPPROTO_TCP || ip6h->nexthdr == IPPROTO_UDP) {
209 csum = (u16 *)rmnet_map_get_csum_field(ip6h->nexthdr, txphdr);
210 *csum = ~(*csum);
211 }
212}
213
214static void
215rmnet_map_ipv6_ul_csum_header(struct ipv6hdr *ipv6hdr,
216 struct rmnet_map_ul_csum_header *ul_header,
217 struct sk_buff *skb)
218{
219 u16 val;
220
221 val = MAP_CSUM_UL_ENABLED_FLAG;
222 if (ipv6hdr->nexthdr == IPPROTO_UDP)
223 val |= MAP_CSUM_UL_UDP_FLAG;
224 val |= skb->csum_offset & MAP_CSUM_UL_OFFSET_MASK;
225
226 ul_header->csum_start_offset = htons(skb_network_header_len(skb));
227 ul_header->csum_info = htons(val);
228
229 skb->ip_summed = CHECKSUM_NONE;
230
231 rmnet_map_complement_ipv6_txporthdr_csum_field(ipv6hdr);
232}
233#else
234static void
235rmnet_map_ipv6_ul_csum_header(void *ip6hdr,
236 struct rmnet_map_ul_csum_header *ul_header,
237 struct sk_buff *skb)
238{
239}
240#endif
241
242static void rmnet_map_v5_checksum_uplink_packet(struct sk_buff *skb,
243 struct rmnet_port *port,
244 struct net_device *orig_dev)
245{
246 struct rmnet_priv *priv = netdev_priv(orig_dev);
247 struct rmnet_map_v5_csum_header *ul_header;
248
249 ul_header = skb_push(skb, sizeof(*ul_header));
250 memset(ul_header, 0, sizeof(*ul_header));
251 ul_header->header_info = u8_encode_bits(RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD,
252 MAPV5_HDRINFO_HDR_TYPE_FMASK);
253
254 if (skb->ip_summed == CHECKSUM_PARTIAL) {
255 void *iph = ip_hdr(skb);
256 __sum16 *check;
257 void *trans;
258 u8 proto;
259
260 if (skb->protocol == htons(ETH_P_IP)) {
261 u16 ip_len = ((struct iphdr *)iph)->ihl * 4;
262
263 proto = ((struct iphdr *)iph)->protocol;
264 trans = iph + ip_len;
265 } else if (IS_ENABLED(CONFIG_IPV6) &&
266 skb->protocol == htons(ETH_P_IPV6)) {
267 u16 ip_len = sizeof(struct ipv6hdr);
268
269 proto = ((struct ipv6hdr *)iph)->nexthdr;
270 trans = iph + ip_len;
271 } else {
272 priv->stats.csum_err_invalid_ip_version++;
273 goto sw_csum;
274 }
275
276 check = rmnet_map_get_csum_field(proto, trans);
277 if (check) {
278 skb->ip_summed = CHECKSUM_NONE;
279 /* Ask for checksum offloading */
280 ul_header->csum_info |= MAPV5_CSUMINFO_VALID_FLAG;
281 priv->stats.csum_hw++;
282 return;
283 }
284 }
285
286sw_csum:
287 priv->stats.csum_sw++;
288}
289
290/* Adds MAP header to front of skb->data
291 * Padding is calculated and set appropriately in MAP header. Mux ID is
292 * initialized to 0.
293 */
294struct rmnet_map_header *rmnet_map_add_map_header(struct sk_buff *skb,
295 int hdrlen,
296 struct rmnet_port *port,
297 int pad)
298{
299 struct rmnet_map_header *map_header;
300 u32 padding, map_datalen;
301
302 map_datalen = skb->len - hdrlen;
303 map_header = (struct rmnet_map_header *)
304 skb_push(skb, sizeof(struct rmnet_map_header));
305 memset(map_header, 0, sizeof(struct rmnet_map_header));
306
307 /* Set next_hdr bit for csum offload packets */
308 if (port->data_format & RMNET_FLAGS_EGRESS_MAP_CKSUMV5)
309 map_header->flags |= MAP_NEXT_HEADER_FLAG;
310
311 if (pad == RMNET_MAP_NO_PAD_BYTES) {
312 map_header->pkt_len = htons(map_datalen);
313 return map_header;
314 }
315
316 BUILD_BUG_ON(MAP_PAD_LEN_MASK < 3);
317 padding = ALIGN(map_datalen, 4) - map_datalen;
318
319 if (padding == 0)
320 goto done;
321
322 if (skb_tailroom(skb) < padding)
323 return NULL;
324
325 skb_put_zero(skb, padding);
326
327done:
328 map_header->pkt_len = htons(map_datalen + padding);
329 /* This is a data packet, so the CMD bit is 0 */
330 map_header->flags = padding & MAP_PAD_LEN_MASK;
331
332 return map_header;
333}
334
335/* Deaggregates a single packet
336 * A whole new buffer is allocated for each portion of an aggregated frame.
337 * Caller should keep calling deaggregate() on the source skb until 0 is
338 * returned, indicating that there are no more packets to deaggregate. Caller
339 * is responsible for freeing the original skb.
340 */
341struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb,
342 struct rmnet_port *port)
343{
344 struct rmnet_map_v5_csum_header *next_hdr = NULL;
345 struct rmnet_map_header *maph;
346 void *data = skb->data;
347 struct sk_buff *skbn;
348 u8 nexthdr_type;
349 u32 packet_len;
350
351 if (skb->len == 0)
352 return NULL;
353
354 maph = (struct rmnet_map_header *)skb->data;
355 packet_len = ntohs(maph->pkt_len) + sizeof(*maph);
356
357 if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV4) {
358 packet_len += sizeof(struct rmnet_map_dl_csum_trailer);
359 } else if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV5) {
360 if (!(maph->flags & MAP_CMD_FLAG)) {
361 packet_len += sizeof(*next_hdr);
362 if (maph->flags & MAP_NEXT_HEADER_FLAG)
363 next_hdr = data + sizeof(*maph);
364 else
365 /* Mapv5 data pkt without csum hdr is invalid */
366 return NULL;
367 }
368 }
369
370 if (((int)skb->len - (int)packet_len) < 0)
371 return NULL;
372
373 /* Some hardware can send us empty frames. Catch them */
374 if (!maph->pkt_len)
375 return NULL;
376
377 if (next_hdr) {
378 nexthdr_type = u8_get_bits(next_hdr->header_info,
379 MAPV5_HDRINFO_HDR_TYPE_FMASK);
380 if (nexthdr_type != RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD)
381 return NULL;
382 }
383
384 skbn = alloc_skb(packet_len + RMNET_MAP_DEAGGR_SPACING, GFP_ATOMIC);
385 if (!skbn)
386 return NULL;
387
388 skb_reserve(skbn, RMNET_MAP_DEAGGR_HEADROOM);
389 skb_put(skbn, packet_len);
390 memcpy(skbn->data, skb->data, packet_len);
391 skb_pull(skb, packet_len);
392
393 return skbn;
394}
395
396/* Validates packet checksums. Function takes a pointer to
397 * the beginning of a buffer which contains the IP payload +
398 * padding + checksum trailer.
399 * Only IPv4 and IPv6 are supported along with TCP & UDP.
400 * Fragmented or tunneled packets are not supported.
401 */
402int rmnet_map_checksum_downlink_packet(struct sk_buff *skb, u16 len)
403{
404 struct rmnet_priv *priv = netdev_priv(skb->dev);
405 struct rmnet_map_dl_csum_trailer *csum_trailer;
406
407 if (unlikely(!(skb->dev->features & NETIF_F_RXCSUM))) {
408 priv->stats.csum_sw++;
409 return -EOPNOTSUPP;
410 }
411
412 csum_trailer = (struct rmnet_map_dl_csum_trailer *)(skb->data + len);
413
414 if (!(csum_trailer->flags & MAP_CSUM_DL_VALID_FLAG)) {
415 priv->stats.csum_valid_unset++;
416 return -EINVAL;
417 }
418
419 if (skb->protocol == htons(ETH_P_IP))
420 return rmnet_map_ipv4_dl_csum_trailer(skb, csum_trailer, priv);
421
422 if (IS_ENABLED(CONFIG_IPV6) && skb->protocol == htons(ETH_P_IPV6))
423 return rmnet_map_ipv6_dl_csum_trailer(skb, csum_trailer, priv);
424
425 priv->stats.csum_err_invalid_ip_version++;
426
427 return -EPROTONOSUPPORT;
428}
429
430static void rmnet_map_v4_checksum_uplink_packet(struct sk_buff *skb,
431 struct net_device *orig_dev)
432{
433 struct rmnet_priv *priv = netdev_priv(orig_dev);
434 struct rmnet_map_ul_csum_header *ul_header;
435 void *iphdr;
436
437 ul_header = (struct rmnet_map_ul_csum_header *)
438 skb_push(skb, sizeof(struct rmnet_map_ul_csum_header));
439
440 if (unlikely(!(orig_dev->features &
441 (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM))))
442 goto sw_csum;
443
444 if (skb->ip_summed != CHECKSUM_PARTIAL)
445 goto sw_csum;
446
447 iphdr = (char *)ul_header +
448 sizeof(struct rmnet_map_ul_csum_header);
449
450 if (skb->protocol == htons(ETH_P_IP)) {
451 rmnet_map_ipv4_ul_csum_header(iphdr, ul_header, skb);
452 priv->stats.csum_hw++;
453 return;
454 }
455
456 if (IS_ENABLED(CONFIG_IPV6) && skb->protocol == htons(ETH_P_IPV6)) {
457 rmnet_map_ipv6_ul_csum_header(iphdr, ul_header, skb);
458 priv->stats.csum_hw++;
459 return;
460 }
461
462 priv->stats.csum_err_invalid_ip_version++;
463
464sw_csum:
465 memset(ul_header, 0, sizeof(*ul_header));
466
467 priv->stats.csum_sw++;
468}
469
470/* Generates UL checksum meta info header for IPv4 and IPv6 over TCP and UDP
471 * packets that are supported for UL checksum offload.
472 */
473void rmnet_map_checksum_uplink_packet(struct sk_buff *skb,
474 struct rmnet_port *port,
475 struct net_device *orig_dev,
476 int csum_type)
477{
478 switch (csum_type) {
479 case RMNET_FLAGS_EGRESS_MAP_CKSUMV4:
480 rmnet_map_v4_checksum_uplink_packet(skb, orig_dev);
481 break;
482 case RMNET_FLAGS_EGRESS_MAP_CKSUMV5:
483 rmnet_map_v5_checksum_uplink_packet(skb, port, orig_dev);
484 break;
485 default:
486 break;
487 }
488}
489
490/* Process a MAPv5 packet header */
491int rmnet_map_process_next_hdr_packet(struct sk_buff *skb,
492 u16 len)
493{
494 struct rmnet_priv *priv = netdev_priv(skb->dev);
495 struct rmnet_map_v5_csum_header *next_hdr;
496 u8 nexthdr_type;
497
498 next_hdr = (struct rmnet_map_v5_csum_header *)(skb->data +
499 sizeof(struct rmnet_map_header));
500
501 nexthdr_type = u8_get_bits(next_hdr->header_info,
502 MAPV5_HDRINFO_HDR_TYPE_FMASK);
503
504 if (nexthdr_type != RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD)
505 return -EINVAL;
506
507 if (unlikely(!(skb->dev->features & NETIF_F_RXCSUM))) {
508 priv->stats.csum_sw++;
509 } else if (next_hdr->csum_info & MAPV5_CSUMINFO_VALID_FLAG) {
510 priv->stats.csum_ok++;
511 skb->ip_summed = CHECKSUM_UNNECESSARY;
512 } else {
513 priv->stats.csum_valid_unset++;
514 }
515
516 /* Pull csum v5 header */
517 skb_pull(skb, sizeof(*next_hdr));
518
519 return 0;
520}