rxe_icrc.c

  1// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
  2/*
  3 * Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
  4 * Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
  5 */
  6
  7#include <linux/crc32.h>
  8
  9#include "rxe.h"
 10#include "rxe_loc.h"
 11
 12/**
 13 * rxe_crc32() - Compute cumulative crc32 for a contiguous segment
 14 * @rxe: rdma_rxe device object
 15 * @crc: starting crc32 value from previous segments
 16 * @next: starting address of current segment
 17 * @len: length of current segment
 18 *
 19 * Return: the cumulative crc32 checksum
 20 */
 21static __be32 rxe_crc32(struct rxe_dev *rxe, __be32 crc, void *next, size_t len)
 22{
 23	return (__force __be32)crc32_le((__force u32)crc, next, len);
 24}
 25
 26/**
 27 * rxe_icrc_hdr() - Compute the partial ICRC for the network and transport
 28 *		  headers of a packet.
 29 * @skb: packet buffer
 30 * @pkt: packet information
 31 *
 32 * Return: the partial ICRC
 33 */
 34static __be32 rxe_icrc_hdr(struct sk_buff *skb, struct rxe_pkt_info *pkt)
 35{
 36	unsigned int bth_offset = 0;
 37	struct iphdr *ip4h = NULL;
 38	struct ipv6hdr *ip6h = NULL;
 39	struct udphdr *udph;
 40	struct rxe_bth *bth;
 41	__be32 crc;
 42	int length;
 43	int hdr_size = sizeof(struct udphdr) +
 44		(skb->protocol == htons(ETH_P_IP) ?
 45		sizeof(struct iphdr) : sizeof(struct ipv6hdr));
 46	/* pseudo header buffer size is calculate using ipv6 header size since
 47	 * it is bigger than ipv4
 48	 */
 49	u8 pshdr[sizeof(struct udphdr) +
 50		sizeof(struct ipv6hdr) +
 51		RXE_BTH_BYTES];
 52
 53	/* This seed is the result of computing a CRC with a seed of
 54	 * 0xfffffff and 8 bytes of 0xff representing a masked LRH.
 55	 */
 56	crc = (__force __be32)0xdebb20e3;
 57
 58	if (skb->protocol == htons(ETH_P_IP)) { /* IPv4 */
 59		memcpy(pshdr, ip_hdr(skb), hdr_size);
 60		ip4h = (struct iphdr *)pshdr;
 61		udph = (struct udphdr *)(ip4h + 1);
 62
 63		ip4h->ttl = 0xff;
 64		ip4h->check = CSUM_MANGLED_0;
 65		ip4h->tos = 0xff;
 66	} else {				/* IPv6 */
 67		memcpy(pshdr, ipv6_hdr(skb), hdr_size);
 68		ip6h = (struct ipv6hdr *)pshdr;
 69		udph = (struct udphdr *)(ip6h + 1);
 70
 71		memset(ip6h->flow_lbl, 0xff, sizeof(ip6h->flow_lbl));
 72		ip6h->priority = 0xf;
 73		ip6h->hop_limit = 0xff;
 74	}
 75	udph->check = CSUM_MANGLED_0;
 76
 77	bth_offset += hdr_size;
 78
 79	memcpy(&pshdr[bth_offset], pkt->hdr, RXE_BTH_BYTES);
 80	bth = (struct rxe_bth *)&pshdr[bth_offset];
 81
 82	/* exclude bth.resv8a */
 83	bth->qpn |= cpu_to_be32(~BTH_QPN_MASK);
 84
 85	length = hdr_size + RXE_BTH_BYTES;
 86	crc = rxe_crc32(pkt->rxe, crc, pshdr, length);
 87
 88	/* And finish to compute the CRC on the remainder of the headers. */
 89	crc = rxe_crc32(pkt->rxe, crc, pkt->hdr + RXE_BTH_BYTES,
 90			rxe_opcode[pkt->opcode].length - RXE_BTH_BYTES);
 91	return crc;
 92}
 93
 94/**
 95 * rxe_icrc_check() - Compute ICRC for a packet and compare to the ICRC
 96 *		      delivered in the packet.
 97 * @skb: packet buffer
 98 * @pkt: packet information
 99 *
100 * Return: 0 if the values match else an error
101 */
102int rxe_icrc_check(struct sk_buff *skb, struct rxe_pkt_info *pkt)
103{
104	__be32 *icrcp;
105	__be32 pkt_icrc;
106	__be32 icrc;
107
108	icrcp = (__be32 *)(pkt->hdr + pkt->paylen - RXE_ICRC_SIZE);
109	pkt_icrc = *icrcp;
110
111	icrc = rxe_icrc_hdr(skb, pkt);
112	icrc = rxe_crc32(pkt->rxe, icrc, (u8 *)payload_addr(pkt),
113				payload_size(pkt) + bth_pad(pkt));
114	icrc = ~icrc;
115
116	if (unlikely(icrc != pkt_icrc))
117		return -EINVAL;
118
119	return 0;
120}
121
122/**
123 * rxe_icrc_generate() - compute ICRC for a packet.
124 * @skb: packet buffer
125 * @pkt: packet information
126 */
127void rxe_icrc_generate(struct sk_buff *skb, struct rxe_pkt_info *pkt)
128{
129	__be32 *icrcp;
130	__be32 icrc;
131
132	icrcp = (__be32 *)(pkt->hdr + pkt->paylen - RXE_ICRC_SIZE);
133	icrc = rxe_icrc_hdr(skb, pkt);
134	icrc = rxe_crc32(pkt->rxe, icrc, (u8 *)payload_addr(pkt),
135				payload_size(pkt) + bth_pad(pkt));
136	*icrcp = ~icrc;
137}