include/net/esp.h

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