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_icrc_init() - Initialize crypto function for computing crc32
14  * @rxe: rdma_rxe device object
15  *
16  * Return: 0 on success else an error
17  */
18 int rxe_icrc_init(struct rxe_dev *rxe)
19 {
20 	struct crypto_shash *tfm;
21 
22 	tfm = crypto_alloc_shash("crc32", 0, 0);
23 	if (IS_ERR(tfm)) {
24 		pr_warn("failed to init crc32 algorithm err:%ld\n",
25 			       PTR_ERR(tfm));
26 		return PTR_ERR(tfm);
27 	}
28 
29 	rxe->tfm = tfm;
30 
31 	return 0;
32 }
33 
34 /**
35  * rxe_crc32() - Compute cumulative crc32 for a contiguous segment
36  * @rxe: rdma_rxe device object
37  * @crc: starting crc32 value from previous segments
38  * @next: starting address of current segment
39  * @len: length of current segment
40  *
41  * Return: the cumulative crc32 checksum
42  */
43 static __be32 rxe_crc32(struct rxe_dev *rxe, __be32 crc, void *next, size_t len)
44 {
45 	__be32 icrc;
46 	int err;
47 
48 	SHASH_DESC_ON_STACK(shash, rxe->tfm);
49 
50 	shash->tfm = rxe->tfm;
51 	*(__be32 *)shash_desc_ctx(shash) = crc;
52 	err = crypto_shash_update(shash, next, len);
53 	if (unlikely(err)) {
54 		pr_warn_ratelimited("failed crc calculation, err: %d\n", err);
55 		return (__force __be32)crc32_le((__force u32)crc, next, len);
56 	}
57 
58 	icrc = *(__be32 *)shash_desc_ctx(shash);
59 	barrier_data(shash_desc_ctx(shash));
60 
61 	return icrc;
62 }
63 
64 /**
65  * rxe_icrc_hdr() - Compute the partial ICRC for the network and transport
66  *		  headers of a packet.
67  * @skb: packet buffer
68  * @pkt: packet information
69  *
70  * Return: the partial ICRC
71  */
72 static __be32 rxe_icrc_hdr(struct sk_buff *skb, struct rxe_pkt_info *pkt)
73 {
74 	unsigned int bth_offset = 0;
75 	struct iphdr *ip4h = NULL;
76 	struct ipv6hdr *ip6h = NULL;
77 	struct udphdr *udph;
78 	struct rxe_bth *bth;
79 	__be32 crc;
80 	int length;
81 	int hdr_size = sizeof(struct udphdr) +
82 		(skb->protocol == htons(ETH_P_IP) ?
83 		sizeof(struct iphdr) : sizeof(struct ipv6hdr));
84 	/* pseudo header buffer size is calculate using ipv6 header size since
85 	 * it is bigger than ipv4
86 	 */
87 	u8 pshdr[sizeof(struct udphdr) +
88 		sizeof(struct ipv6hdr) +
89 		RXE_BTH_BYTES];
90 
91 	/* This seed is the result of computing a CRC with a seed of
92 	 * 0xfffffff and 8 bytes of 0xff representing a masked LRH.
93 	 */
94 	crc = (__force __be32)0xdebb20e3;
95 
96 	if (skb->protocol == htons(ETH_P_IP)) { /* IPv4 */
97 		memcpy(pshdr, ip_hdr(skb), hdr_size);
98 		ip4h = (struct iphdr *)pshdr;
99 		udph = (struct udphdr *)(ip4h + 1);
100 
101 		ip4h->ttl = 0xff;
102 		ip4h->check = CSUM_MANGLED_0;
103 		ip4h->tos = 0xff;
104 	} else {				/* IPv6 */
105 		memcpy(pshdr, ipv6_hdr(skb), hdr_size);
106 		ip6h = (struct ipv6hdr *)pshdr;
107 		udph = (struct udphdr *)(ip6h + 1);
108 
109 		memset(ip6h->flow_lbl, 0xff, sizeof(ip6h->flow_lbl));
110 		ip6h->priority = 0xf;
111 		ip6h->hop_limit = 0xff;
112 	}
113 	udph->check = CSUM_MANGLED_0;
114 
115 	bth_offset += hdr_size;
116 
117 	memcpy(&pshdr[bth_offset], pkt->hdr, RXE_BTH_BYTES);
118 	bth = (struct rxe_bth *)&pshdr[bth_offset];
119 
120 	/* exclude bth.resv8a */
121 	bth->qpn |= cpu_to_be32(~BTH_QPN_MASK);
122 
123 	length = hdr_size + RXE_BTH_BYTES;
124 	crc = rxe_crc32(pkt->rxe, crc, pshdr, length);
125 
126 	/* And finish to compute the CRC on the remainder of the headers. */
127 	crc = rxe_crc32(pkt->rxe, crc, pkt->hdr + RXE_BTH_BYTES,
128 			rxe_opcode[pkt->opcode].length - RXE_BTH_BYTES);
129 	return crc;
130 }
131 
132 /**
133  * rxe_icrc_check() - Compute ICRC for a packet and compare to the ICRC
134  *		      delivered in the packet.
135  * @skb: packet buffer
136  * @pkt: packet information
137  *
138  * Return: 0 if the values match else an error
139  */
140 int rxe_icrc_check(struct sk_buff *skb, struct rxe_pkt_info *pkt)
141 {
142 	__be32 *icrcp;
143 	__be32 pkt_icrc;
144 	__be32 icrc;
145 
146 	icrcp = (__be32 *)(pkt->hdr + pkt->paylen - RXE_ICRC_SIZE);
147 	pkt_icrc = *icrcp;
148 
149 	icrc = rxe_icrc_hdr(skb, pkt);
150 	icrc = rxe_crc32(pkt->rxe, icrc, (u8 *)payload_addr(pkt),
151 				payload_size(pkt) + bth_pad(pkt));
152 	icrc = ~icrc;
153 
154 	if (unlikely(icrc != pkt_icrc))
155 		return -EINVAL;
156 
157 	return 0;
158 }
159 
160 /**
161  * rxe_icrc_generate() - compute ICRC for a packet.
162  * @skb: packet buffer
163  * @pkt: packet information
164  */
165 void rxe_icrc_generate(struct sk_buff *skb, struct rxe_pkt_info *pkt)
166 {
167 	__be32 *icrcp;
168 	__be32 icrc;
169 
170 	icrcp = (__be32 *)(pkt->hdr + pkt->paylen - RXE_ICRC_SIZE);
171 	icrc = rxe_icrc_hdr(skb, pkt);
172 	icrc = rxe_crc32(pkt->rxe, icrc, (u8 *)payload_addr(pkt),
173 				payload_size(pkt) + bth_pad(pkt));
174 	*icrcp = ~icrc;
175 }
176