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  */
fc_frame_crc_check(struct fc_frame * fp)22 u32 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 }
37 EXPORT_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  */
_fc_frame_alloc(size_t len)43 struct 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 }
60 EXPORT_SYMBOL(_fc_frame_alloc);
61 
fc_frame_alloc_fill(struct fc_lport * lp,size_t payload_len)62 struct 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 }
79 EXPORT_SYMBOL(fc_frame_alloc_fill);
80