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   1 #ifndef _NET_ESP_H
   2 #define _NET_ESP_H
   3
   4 #include <net/xfrm.h>
   5 #include <asm/scatterlist.h>
   6
   7 #define ESP_NUM_FAST_SG         4
   8
   9 struct esp_data
  10 {
  11         struct scatterlist              sgbuf[ESP_NUM_FAST_SG];
  12
  13         /* Confidentiality */
  14         struct {
  15                 u8                      *key;           /* Key */
  16                 int                     key_len;        /* Key length */
  17                 u8                      *ivec;          /* ivec buffer */
  18                 /* ivlen is offset from enc_data, where encrypted data start.
  19                  * It is logically different of crypto_tfm_alg_ivsize(tfm).
  20                  * We assume that it is either zero (no ivec), or
  21                  * >= crypto_tfm_alg_ivsize(tfm). */
  22                 int                     ivlen;
  23                 int                     padlen;         /* 0..255 */
  24                 struct crypto_tfm       *tfm;           /* crypto handle */
  25         } conf;
  26
  27         /* Integrity. It is active when icv_full_len != 0 */
  28         struct {
  29                 u8                      *key;           /* Key */
  30                 int                     key_len;        /* Length of the key */
  31                 u8                      *work_icv;
  32                 int                     icv_full_len;
  33                 int                     icv_trunc_len;
  34                 void                    (*icv)(struct esp_data*,
  35                                                struct sk_buff *skb,
  36                                                int offset, int len, u8 *icv);
  37                 struct crypto_tfm       *tfm;
  38         } auth;
  39 };
  40
  41 extern int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len);
  42 extern int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer);
  43 extern void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len);
  44
  45 static inline void
  46 esp_hmac_digest(struct esp_data *esp, struct sk_buff *skb, int offset,
  47                 int len, u8 *auth_data)
  48 {
  49         struct crypto_tfm *tfm = esp->auth.tfm;
  50         char *icv = esp->auth.work_icv;
  51
  52         memset(auth_data, 0, esp->auth.icv_trunc_len);
  53         crypto_hmac_init(tfm, esp->auth.key, &esp->auth.key_len);
  54         skb_icv_walk(skb, tfm, offset, len, crypto_hmac_update);
  55         crypto_hmac_final(tfm, esp->auth.key, &esp->auth.key_len, icv);
  56         memcpy(auth_data, icv, esp->auth.icv_trunc_len);
  57 }
  58
  59 #endif