1 /* 2 * Copyright(c) 2007 Intel Corporation. All rights reserved. 3 * 4 * This program is free software; you can redistribute it and/or modify it 5 * under the terms and conditions of the GNU General Public License, 6 * version 2, as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope it will be useful, but WITHOUT 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 11 * more details. 12 * 13 * You should have received a copy of the GNU General Public License along with 14 * this program; if not, write to the Free Software Foundation, Inc., 15 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. 16 * 17 * Maintained at www.Open-FCoE.org 18 */ 19 20 /* 21 * Frame allocation. 22 */ 23 #include <linux/module.h> 24 #include <linux/kernel.h> 25 #include <linux/skbuff.h> 26 #include <linux/crc32.h> 27 #include <linux/gfp.h> 28 29 #include <scsi/fc_frame.h> 30 31 /* 32 * Check the CRC in a frame. 33 */ 34 u32 fc_frame_crc_check(struct fc_frame *fp) 35 { 36 u32 crc; 37 u32 error; 38 const u8 *bp; 39 unsigned int len; 40 41 WARN_ON(!fc_frame_is_linear(fp)); 42 fr_flags(fp) &= ~FCPHF_CRC_UNCHECKED; 43 len = (fr_len(fp) + 3) & ~3; /* round up length to include fill */ 44 bp = (const u8 *) fr_hdr(fp); 45 crc = ~crc32(~0, bp, len); 46 error = crc ^ fr_crc(fp); 47 return error; 48 } 49 EXPORT_SYMBOL(fc_frame_crc_check); 50 51 /* 52 * Allocate a frame intended to be sent. 53 * Get an sk_buff for the frame and set the length. 54 */ 55 struct fc_frame *_fc_frame_alloc(size_t len) 56 { 57 struct fc_frame *fp; 58 struct sk_buff *skb; 59 60 WARN_ON((len % sizeof(u32)) != 0); 61 len += sizeof(struct fc_frame_header); 62 skb = alloc_skb_fclone(len + FC_FRAME_HEADROOM + FC_FRAME_TAILROOM + 63 NET_SKB_PAD, GFP_ATOMIC); 64 if (!skb) 65 return NULL; 66 skb_reserve(skb, NET_SKB_PAD + FC_FRAME_HEADROOM); 67 fp = (struct fc_frame *) skb; 68 fc_frame_init(fp); 69 skb_put(skb, len); 70 return fp; 71 } 72 EXPORT_SYMBOL(_fc_frame_alloc); 73 74 struct fc_frame *fc_frame_alloc_fill(struct fc_lport *lp, size_t payload_len) 75 { 76 struct fc_frame *fp; 77 size_t fill; 78 79 fill = payload_len % 4; 80 if (fill != 0) 81 fill = 4 - fill; 82 fp = _fc_frame_alloc(payload_len + fill); 83 if (fp) { 84 memset((char *) fr_hdr(fp) + payload_len, 0, fill); 85 /* trim is OK, we just allocated it so there are no fragments */ 86 skb_trim(fp_skb(fp), 87 payload_len + sizeof(struct fc_frame_header)); 88 } 89 return fp; 90 } 91 EXPORT_SYMBOL(fc_frame_alloc_fill); 92