include/net/esp.h

   1 #ifndef _NET_ESP_H
   2 #define _NET_ESP_H
   3
   4 #include <linux/crypto.h>
   5 #include <net/xfrm.h>
   6 #include <linux/scatterlist.h>
   7
   8 #define ESP_NUM_FAST_SG         4
   9
  10 struct esp_data
  11 {
  12         struct scatterlist              sgbuf[ESP_NUM_FAST_SG];
  13
  14         /* Confidentiality */
  15         struct {
  16                 int                     padlen;         /* 0..255 */
  17                 /* ivlen is offset from enc_data, where encrypted data start.
  18                  * It is logically different of crypto_tfm_alg_ivsize(tfm).
  19                  * We assume that it is either zero (no ivec), or
  20                  * >= crypto_tfm_alg_ivsize(tfm). */
  21                 int                     ivlen;
  22                 int                     ivinitted;
  23                 u8                      *ivec;          /* ivec buffer */
  24                 struct crypto_blkcipher *tfm;           /* crypto handle */
  25         } conf;
  26
  27         /* Integrity. It is active when icv_full_len != 0 */
  28         struct {
  29                 u8                      *work_icv;
  30                 int                     icv_full_len;
  31                 int                     icv_trunc_len;
  32                 struct crypto_hash      *tfm;
  33         } auth;
  34 };
  35
  36 extern void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len);
  37
  38 static inline int esp_mac_digest(struct esp_data *esp, struct sk_buff *skb,
  39                                  int offset, int len)
  40 {
  41         struct hash_desc desc;
  42         int err;
  43
  44         desc.tfm = esp->auth.tfm;
  45         desc.flags = 0;
  46
  47         err = crypto_hash_init(&desc);
  48         if (unlikely(err))
  49                 return err;
  50         err = skb_icv_walk(skb, &desc, offset, len, crypto_hash_update);
  51         if (unlikely(err))
  52                 return err;
  53         return crypto_hash_final(&desc, esp->auth.work_icv);
  54 }
  55
  56 struct ip_esp_hdr;
  57
  58 static inline struct ip_esp_hdr *ip_esp_hdr(const struct sk_buff *skb)
  59 {
  60         return (struct ip_esp_hdr *)skb_transport_header(skb);
  61 }
  62
  63 #endif