1#ifndef _CRYPTO_GCM_H
2#define _CRYPTO_GCM_H
3
4#include <linux/errno.h>
5
6#include <crypto/aes.h>
7#include <crypto/gf128mul.h>
8
9#define GCM_AES_IV_SIZE 12
10#define GCM_RFC4106_IV_SIZE 8
11#define GCM_RFC4543_IV_SIZE 8
12
13/*
14 * validate authentication tag for GCM
15 */
16static inline int crypto_gcm_check_authsize(unsigned int authsize)
17{
18	switch (authsize) {
19	case 4:
20	case 8:
21	case 12:
22	case 13:
23	case 14:
24	case 15:
25	case 16:
26		break;
27	default:
28		return -EINVAL;
29	}
30
31	return 0;
32}
33
34/*
35 * validate authentication tag for RFC4106
36 */
37static inline int crypto_rfc4106_check_authsize(unsigned int authsize)
38{
39	switch (authsize) {
40	case 8:
41	case 12:
42	case 16:
43		break;
44	default:
45		return -EINVAL;
46	}
47
48	return 0;
49}
50
51/*
52 * validate assoclen for RFC4106/RFC4543
53 */
54static inline int crypto_ipsec_check_assoclen(unsigned int assoclen)
55{
56	switch (assoclen) {
57	case 16:
58	case 20:
59		break;
60	default:
61		return -EINVAL;
62	}
63
64	return 0;
65}
66
67struct aesgcm_ctx {
68	be128			ghash_key;
69	struct crypto_aes_ctx	aes_ctx;
70	unsigned int		authsize;
71};
72
73int aesgcm_expandkey(struct aesgcm_ctx *ctx, const u8 *key,
74		     unsigned int keysize, unsigned int authsize);
75
76void aesgcm_encrypt(const struct aesgcm_ctx *ctx, u8 *dst, const u8 *src,
77		    int crypt_len, const u8 *assoc, int assoc_len,
78		    const u8 iv[GCM_AES_IV_SIZE], u8 *authtag);
79
80bool __must_check aesgcm_decrypt(const struct aesgcm_ctx *ctx, u8 *dst,
81				 const u8 *src, int crypt_len, const u8 *assoc,
82				 int assoc_len, const u8 iv[GCM_AES_IV_SIZE],
83				 const u8 *authtag);
84
85#endif
86