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 28 #include <scsi/fc_frame.h> 29 30 /* 31 * Check the CRC in a frame. 32 */ 33 u32 fc_frame_crc_check(struct fc_frame *fp) 34 { 35 u32 crc; 36 u32 error; 37 const u8 *bp; 38 unsigned int len; 39 40 WARN_ON(!fc_frame_is_linear(fp)); 41 fr_flags(fp) &= ~FCPHF_CRC_UNCHECKED; 42 len = (fr_len(fp) + 3) & ~3; /* round up length to include fill */ 43 bp = (const u8 *) fr_hdr(fp); 44 crc = ~crc32(~0, bp, len); 45 error = crc ^ fr_crc(fp); 46 return error; 47 } 48 EXPORT_SYMBOL(fc_frame_crc_check); 49 50 /* 51 * Allocate a frame intended to be sent via fcoe_xmit. 52 * Get an sk_buff for the frame and set the length. 53 */ 54 struct fc_frame *__fc_frame_alloc(size_t len) 55 { 56 struct fc_frame *fp; 57 struct sk_buff *skb; 58 59 WARN_ON((len % sizeof(u32)) != 0); 60 len += sizeof(struct fc_frame_header); 61 skb = dev_alloc_skb(len + FC_FRAME_HEADROOM + FC_FRAME_TAILROOM); 62 if (!skb) 63 return NULL; 64 fp = (struct fc_frame *) skb; 65 fc_frame_init(fp); 66 skb_reserve(skb, FC_FRAME_HEADROOM); 67 skb_put(skb, len); 68 return fp; 69 } 70 EXPORT_SYMBOL(__fc_frame_alloc); 71 72 73 struct fc_frame *fc_frame_alloc_fill(struct fc_lport *lp, size_t payload_len) 74 { 75 struct fc_frame *fp; 76 size_t fill; 77 78 fill = payload_len % 4; 79 if (fill != 0) 80 fill = 4 - fill; 81 fp = __fc_frame_alloc(payload_len + fill); 82 if (fp) { 83 memset((char *) fr_hdr(fp) + payload_len, 0, fill); 84 /* trim is OK, we just allocated it so there are no fragments */ 85 skb_trim(fp_skb(fp), 86 payload_len + sizeof(struct fc_frame_header)); 87 } 88 return fp; 89 } 90