1// SPDX-License-Identifier: GPL-2.0-only
2/****************************************************************************
3 * Driver for Solarflare network controllers and boards
4 * Copyright 2005-2006 Fen Systems Ltd.
5 * Copyright 2005-2013 Solarflare Communications Inc.
6 */
7
8#include <linux/socket.h>
9#include <linux/in.h>
10#include <linux/slab.h>
11#include <linux/ip.h>
12#include <linux/ipv6.h>
13#include <linux/tcp.h>
14#include <linux/udp.h>
15#include <linux/prefetch.h>
16#include <linux/moduleparam.h>
17#include <linux/iommu.h>
18#include <net/ip.h>
19#include <net/checksum.h>
20#include <net/xdp.h>
21#include <linux/bpf_trace.h>
22#include "net_driver.h"
23#include "efx.h"
24#include "rx_common.h"
25#include "filter.h"
26#include "nic.h"
27#include "selftest.h"
28#include "workarounds.h"
29
30/* Preferred number of descriptors to fill at once */
31#define EFX_RX_PREFERRED_BATCH 8U
32
33/* Maximum rx prefix used by any architecture. */
34#define EFX_MAX_RX_PREFIX_SIZE 16
35
36/* Size of buffer allocated for skb header area. */
37#define EFX_SKB_HEADERS 128u
38
39/* Each packet can consume up to ceil(max_frame_len / buffer_size) buffers */
40#define EFX_RX_MAX_FRAGS DIV_ROUND_UP(EFX_MAX_FRAME_LEN(EFX_MAX_MTU), \
41 EFX_RX_USR_BUF_SIZE)
42
43static void efx_rx_packet__check_len(struct efx_rx_queue *rx_queue,
44 struct efx_rx_buffer *rx_buf,
45 int len)
46{
47 struct efx_nic *efx = rx_queue->efx;
48 unsigned max_len = rx_buf->len - efx->type->rx_buffer_padding;
49
50 if (likely(len <= max_len))
51 return;
52
53 /* The packet must be discarded, but this is only a fatal error
54 * if the caller indicated it was
55 */
56 rx_buf->flags |= EFX_RX_PKT_DISCARD;
57
58 if (net_ratelimit())
59 netif_err(efx, rx_err, efx->net_dev,
60 "RX queue %d overlength RX event (%#x > %#x)\n",
61 efx_rx_queue_index(rx_queue), len, max_len);
62
63 efx_rx_queue_channel(rx_queue)->n_rx_overlength++;
64}
65
66/* Allocate and construct an SKB around page fragments */
67static struct sk_buff *efx_rx_mk_skb(struct efx_channel *channel,
68 struct efx_rx_buffer *rx_buf,
69 unsigned int n_frags,
70 u8 *eh, int hdr_len)
71{
72 struct efx_nic *efx = channel->efx;
73 struct sk_buff *skb;
74
75 /* Allocate an SKB to store the headers */
76 skb = netdev_alloc_skb(dev: efx->net_dev,
77 length: efx->rx_ip_align + efx->rx_prefix_size +
78 hdr_len);
79 if (unlikely(skb == NULL)) {
80 atomic_inc(v: &efx->n_rx_noskb_drops);
81 return NULL;
82 }
83
84 EFX_WARN_ON_ONCE_PARANOID(rx_buf->len < hdr_len);
85
86 memcpy(skb->data + efx->rx_ip_align, eh - efx->rx_prefix_size,
87 efx->rx_prefix_size + hdr_len);
88 skb_reserve(skb, len: efx->rx_ip_align + efx->rx_prefix_size);
89 __skb_put(skb, len: hdr_len);
90
91 /* Append the remaining page(s) onto the frag list */
92 if (rx_buf->len > hdr_len) {
93 rx_buf->page_offset += hdr_len;
94 rx_buf->len -= hdr_len;
95
96 for (;;) {
97 skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
98 page: rx_buf->page, off: rx_buf->page_offset,
99 size: rx_buf->len, truesize: efx->rx_buffer_truesize);
100 rx_buf->page = NULL;
101
102 if (skb_shinfo(skb)->nr_frags == n_frags)
103 break;
104
105 rx_buf = efx_rx_buf_next(rx_queue: &channel->rx_queue, rx_buf);
106 }
107 } else {
108 __free_pages(page: rx_buf->page, order: efx->rx_buffer_order);
109 rx_buf->page = NULL;
110 n_frags = 0;
111 }
112
113 /* Move past the ethernet header */
114 skb->protocol = eth_type_trans(skb, dev: efx->net_dev);
115
116 skb_mark_napi_id(skb, napi: &channel->napi_str);
117
118 return skb;
119}
120
121void efx_rx_packet(struct efx_rx_queue *rx_queue, unsigned int index,
122 unsigned int n_frags, unsigned int len, u16 flags)
123{
124 struct efx_nic *efx = rx_queue->efx;
125 struct efx_channel *channel = efx_rx_queue_channel(rx_queue);
126 struct efx_rx_buffer *rx_buf;
127
128 rx_queue->rx_packets++;
129
130 rx_buf = efx_rx_buffer(rx_queue, index);
131 rx_buf->flags |= flags;
132
133 /* Validate the number of fragments and completed length */
134 if (n_frags == 1) {
135 if (!(flags & EFX_RX_PKT_PREFIX_LEN))
136 efx_rx_packet__check_len(rx_queue, rx_buf, len);
137 } else if (unlikely(n_frags > EFX_RX_MAX_FRAGS) ||
138 unlikely(len <= (n_frags - 1) * efx->rx_dma_len) ||
139 unlikely(len > n_frags * efx->rx_dma_len) ||
140 unlikely(!efx->rx_scatter)) {
141 /* If this isn't an explicit discard request, either
142 * the hardware or the driver is broken.
143 */
144 WARN_ON(!(len == 0 && rx_buf->flags & EFX_RX_PKT_DISCARD));
145 rx_buf->flags |= EFX_RX_PKT_DISCARD;
146 }
147
148 netif_vdbg(efx, rx_status, efx->net_dev,
149 "RX queue %d received ids %x-%x len %d %s%s\n",
150 efx_rx_queue_index(rx_queue), index,
151 (index + n_frags - 1) & rx_queue->ptr_mask, len,
152 (rx_buf->flags & EFX_RX_PKT_CSUMMED) ? " [SUMMED]" : "",
153 (rx_buf->flags & EFX_RX_PKT_DISCARD) ? " [DISCARD]" : "");
154
155 /* Discard packet, if instructed to do so. Process the
156 * previous receive first.
157 */
158 if (unlikely(rx_buf->flags & EFX_RX_PKT_DISCARD)) {
159 efx_rx_flush_packet(channel);
160 efx_discard_rx_packet(channel, rx_buf, n_frags);
161 return;
162 }
163
164 if (n_frags == 1 && !(flags & EFX_RX_PKT_PREFIX_LEN))
165 rx_buf->len = len;
166
167 /* Release and/or sync the DMA mapping - assumes all RX buffers
168 * consumed in-order per RX queue.
169 */
170 efx_sync_rx_buffer(efx, rx_buf, len: rx_buf->len);
171
172 /* Prefetch nice and early so data will (hopefully) be in cache by
173 * the time we look at it.
174 */
175 prefetch(efx_rx_buf_va(rx_buf));
176
177 rx_buf->page_offset += efx->rx_prefix_size;
178 rx_buf->len -= efx->rx_prefix_size;
179
180 if (n_frags > 1) {
181 /* Release/sync DMA mapping for additional fragments.
182 * Fix length for last fragment.
183 */
184 unsigned int tail_frags = n_frags - 1;
185
186 for (;;) {
187 rx_buf = efx_rx_buf_next(rx_queue, rx_buf);
188 if (--tail_frags == 0)
189 break;
190 efx_sync_rx_buffer(efx, rx_buf, len: efx->rx_dma_len);
191 }
192 rx_buf->len = len - (n_frags - 1) * efx->rx_dma_len;
193 efx_sync_rx_buffer(efx, rx_buf, len: rx_buf->len);
194 }
195
196 /* All fragments have been DMA-synced, so recycle pages. */
197 rx_buf = efx_rx_buffer(rx_queue, index);
198 efx_recycle_rx_pages(channel, rx_buf, n_frags);
199
200 /* Pipeline receives so that we give time for packet headers to be
201 * prefetched into cache.
202 */
203 efx_rx_flush_packet(channel);
204 channel->rx_pkt_n_frags = n_frags;
205 channel->rx_pkt_index = index;
206}
207
208static void efx_rx_deliver(struct efx_channel *channel, u8 *eh,
209 struct efx_rx_buffer *rx_buf,
210 unsigned int n_frags)
211{
212 struct sk_buff *skb;
213 u16 hdr_len = min_t(u16, rx_buf->len, EFX_SKB_HEADERS);
214
215 skb = efx_rx_mk_skb(channel, rx_buf, n_frags, eh, hdr_len);
216 if (unlikely(skb == NULL)) {
217 struct efx_rx_queue *rx_queue;
218
219 rx_queue = efx_channel_get_rx_queue(channel);
220 efx_free_rx_buffers(rx_queue, rx_buf, num_bufs: n_frags);
221 return;
222 }
223 skb_record_rx_queue(skb, rx_queue: channel->rx_queue.core_index);
224
225 /* Set the SKB flags */
226 skb_checksum_none_assert(skb);
227 if (likely(rx_buf->flags & EFX_RX_PKT_CSUMMED)) {
228 skb->ip_summed = CHECKSUM_UNNECESSARY;
229 skb->csum_level = !!(rx_buf->flags & EFX_RX_PKT_CSUM_LEVEL);
230 }
231
232 efx_rx_skb_attach_timestamp(channel, skb);
233
234 if (channel->type->receive_skb)
235 if (channel->type->receive_skb(channel, skb))
236 return;
237
238 /* Pass the packet up */
239 if (channel->rx_list != NULL)
240 /* Add to list, will pass up later */
241 list_add_tail(new: &skb->list, head: channel->rx_list);
242 else
243 /* No list, so pass it up now */
244 netif_receive_skb(skb);
245}
246
247/** efx_do_xdp: perform XDP processing on a received packet
248 *
249 * Returns true if packet should still be delivered.
250 */
251static bool efx_do_xdp(struct efx_nic *efx, struct efx_channel *channel,
252 struct efx_rx_buffer *rx_buf, u8 **ehp)
253{
254 u8 rx_prefix[EFX_MAX_RX_PREFIX_SIZE];
255 struct efx_rx_queue *rx_queue;
256 struct bpf_prog *xdp_prog;
257 struct xdp_frame *xdpf;
258 struct xdp_buff xdp;
259 u32 xdp_act;
260 s16 offset;
261 int err;
262
263 xdp_prog = rcu_dereference_bh(efx->xdp_prog);
264 if (!xdp_prog)
265 return true;
266
267 rx_queue = efx_channel_get_rx_queue(channel);
268
269 if (unlikely(channel->rx_pkt_n_frags > 1)) {
270 /* We can't do XDP on fragmented packets - drop. */
271 efx_free_rx_buffers(rx_queue, rx_buf,
272 num_bufs: channel->rx_pkt_n_frags);
273 if (net_ratelimit())
274 netif_err(efx, rx_err, efx->net_dev,
275 "XDP is not possible with multiple receive fragments (%d)\n",
276 channel->rx_pkt_n_frags);
277 channel->n_rx_xdp_bad_drops++;
278 return false;
279 }
280
281 dma_sync_single_for_cpu(dev: &efx->pci_dev->dev, addr: rx_buf->dma_addr,
282 size: rx_buf->len, dir: DMA_FROM_DEVICE);
283
284 /* Save the rx prefix. */
285 EFX_WARN_ON_PARANOID(efx->rx_prefix_size > EFX_MAX_RX_PREFIX_SIZE);
286 memcpy(rx_prefix, *ehp - efx->rx_prefix_size,
287 efx->rx_prefix_size);
288
289 xdp_init_buff(xdp: &xdp, frame_sz: efx->rx_page_buf_step, rxq: &rx_queue->xdp_rxq_info);
290 /* No support yet for XDP metadata */
291 xdp_prepare_buff(xdp: &xdp, hard_start: *ehp - EFX_XDP_HEADROOM, EFX_XDP_HEADROOM,
292 data_len: rx_buf->len, meta_valid: false);
293
294 xdp_act = bpf_prog_run_xdp(prog: xdp_prog, xdp: &xdp);
295
296 offset = (u8 *)xdp.data - *ehp;
297
298 switch (xdp_act) {
299 case XDP_PASS:
300 /* Fix up rx prefix. */
301 if (offset) {
302 *ehp += offset;
303 rx_buf->page_offset += offset;
304 rx_buf->len -= offset;
305 memcpy(*ehp - efx->rx_prefix_size, rx_prefix,
306 efx->rx_prefix_size);
307 }
308 break;
309
310 case XDP_TX:
311 /* Buffer ownership passes to tx on success. */
312 xdpf = xdp_convert_buff_to_frame(xdp: &xdp);
313 err = efx_xdp_tx_buffers(efx, n: 1, xdpfs: &xdpf, flush: true);
314 if (unlikely(err != 1)) {
315 efx_free_rx_buffers(rx_queue, rx_buf, num_bufs: 1);
316 if (net_ratelimit())
317 netif_err(efx, rx_err, efx->net_dev,
318 "XDP TX failed (%d)\n", err);
319 channel->n_rx_xdp_bad_drops++;
320 trace_xdp_exception(dev: efx->net_dev, xdp: xdp_prog, act: xdp_act);
321 } else {
322 channel->n_rx_xdp_tx++;
323 }
324 break;
325
326 case XDP_REDIRECT:
327 err = xdp_do_redirect(dev: efx->net_dev, xdp: &xdp, prog: xdp_prog);
328 if (unlikely(err)) {
329 efx_free_rx_buffers(rx_queue, rx_buf, num_bufs: 1);
330 if (net_ratelimit())
331 netif_err(efx, rx_err, efx->net_dev,
332 "XDP redirect failed (%d)\n", err);
333 channel->n_rx_xdp_bad_drops++;
334 trace_xdp_exception(dev: efx->net_dev, xdp: xdp_prog, act: xdp_act);
335 } else {
336 channel->n_rx_xdp_redirect++;
337 }
338 break;
339
340 default:
341 bpf_warn_invalid_xdp_action(dev: efx->net_dev, prog: xdp_prog, act: xdp_act);
342 efx_free_rx_buffers(rx_queue, rx_buf, num_bufs: 1);
343 channel->n_rx_xdp_bad_drops++;
344 trace_xdp_exception(dev: efx->net_dev, xdp: xdp_prog, act: xdp_act);
345 break;
346
347 case XDP_ABORTED:
348 trace_xdp_exception(dev: efx->net_dev, xdp: xdp_prog, act: xdp_act);
349 fallthrough;
350 case XDP_DROP:
351 efx_free_rx_buffers(rx_queue, rx_buf, num_bufs: 1);
352 channel->n_rx_xdp_drops++;
353 break;
354 }
355
356 return xdp_act == XDP_PASS;
357}
358
359/* Handle a received packet. Second half: Touches packet payload. */
360void __efx_rx_packet(struct efx_channel *channel)
361{
362 struct efx_rx_queue *rx_queue = efx_channel_get_rx_queue(channel);
363 struct efx_nic *efx = channel->efx;
364 struct efx_rx_buffer *rx_buf =
365 efx_rx_buffer(rx_queue, index: channel->rx_pkt_index);
366 u8 *eh = efx_rx_buf_va(buf: rx_buf);
367
368 /* Read length from the prefix if necessary. This already
369 * excludes the length of the prefix itself.
370 */
371 if (rx_buf->flags & EFX_RX_PKT_PREFIX_LEN) {
372 rx_buf->len = le16_to_cpup(p: (__le16 *)
373 (eh + efx->rx_packet_len_offset));
374 /* A known issue may prevent this being filled in;
375 * if that happens, just drop the packet.
376 * Must do that in the driver since passing a zero-length
377 * packet up to the stack may cause a crash.
378 */
379 if (unlikely(!rx_buf->len)) {
380 efx_free_rx_buffers(rx_queue, rx_buf,
381 num_bufs: channel->rx_pkt_n_frags);
382 channel->n_rx_frm_trunc++;
383 goto out;
384 }
385 }
386
387 /* If we're in loopback test, then pass the packet directly to the
388 * loopback layer, and free the rx_buf here
389 */
390 if (unlikely(efx->loopback_selftest)) {
391 efx_loopback_rx_packet(efx, buf_ptr: eh, pkt_len: rx_buf->len);
392 efx_free_rx_buffers(rx_queue, rx_buf,
393 num_bufs: channel->rx_pkt_n_frags);
394 goto out;
395 }
396
397 if (!efx_do_xdp(efx, channel, rx_buf, ehp: &eh))
398 goto out;
399
400 if (unlikely(!(efx->net_dev->features & NETIF_F_RXCSUM)))
401 rx_buf->flags &= ~EFX_RX_PKT_CSUMMED;
402
403 if ((rx_buf->flags & EFX_RX_PKT_TCP) && !channel->type->receive_skb)
404 efx_rx_packet_gro(channel, rx_buf, n_frags: channel->rx_pkt_n_frags, eh, csum: 0);
405 else
406 efx_rx_deliver(channel, eh, rx_buf, n_frags: channel->rx_pkt_n_frags);
407out:
408 channel->rx_pkt_n_frags = 0;
409}
410

source code of linux/drivers/net/ethernet/sfc/rx.c