1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright(c) 2007 Intel Corporation. All rights reserved.
4 *
5 * Maintained at www.Open-FCoE.org
6 */
7
8/*
9 * Frame allocation.
10 */
11#include <linux/module.h>
12#include <linux/kernel.h>
13#include <linux/skbuff.h>
14#include <linux/crc32.h>
15#include <linux/gfp.h>
16
17#include <scsi/fc_frame.h>
18
19/*
20 * Check the CRC in a frame.
21 */
22u32 fc_frame_crc_check(struct fc_frame *fp)
23{
24	u32 crc;
25	u32 error;
26	const u8 *bp;
27	unsigned int len;
28
29	WARN_ON(!fc_frame_is_linear(fp));
30	fr_flags(fp) &= ~FCPHF_CRC_UNCHECKED;
31	len = (fr_len(fp) + 3) & ~3;	/* round up length to include fill */
32	bp = (const u8 *) fr_hdr(fp);
33	crc = ~crc32(~0, bp, len);
34	error = crc ^ fr_crc(fp);
35	return error;
36}
37EXPORT_SYMBOL(fc_frame_crc_check);
38
39/*
40 * Allocate a frame intended to be sent.
41 * Get an sk_buff for the frame and set the length.
42 */
43struct fc_frame *_fc_frame_alloc(size_t len)
44{
45	struct fc_frame *fp;
46	struct sk_buff *skb;
47
48	WARN_ON((len % sizeof(u32)) != 0);
49	len += sizeof(struct fc_frame_header);
50	skb = alloc_skb_fclone(len + FC_FRAME_HEADROOM + FC_FRAME_TAILROOM +
51			       NET_SKB_PAD, GFP_ATOMIC);
52	if (!skb)
53		return NULL;
54	skb_reserve(skb, NET_SKB_PAD + FC_FRAME_HEADROOM);
55	fp = (struct fc_frame *) skb;
56	fc_frame_init(fp);
57	skb_put(skb, len);
58	return fp;
59}
60EXPORT_SYMBOL(_fc_frame_alloc);
61
62struct fc_frame *fc_frame_alloc_fill(struct fc_lport *lp, size_t payload_len)
63{
64	struct fc_frame *fp;
65	size_t fill;
66
67	fill = payload_len % 4;
68	if (fill != 0)
69		fill = 4 - fill;
70	fp = _fc_frame_alloc(payload_len + fill);
71	if (fp) {
72		memset((char *) fr_hdr(fp) + payload_len, 0, fill);
73		/* trim is OK, we just allocated it so there are no fragments */
74		skb_trim(fp_skb(fp),
75			 payload_len + sizeof(struct fc_frame_header));
76	}
77	return fp;
78}
79EXPORT_SYMBOL(fc_frame_alloc_fill);
80