curve.h

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * Copyright 2011 - 2013 Daniel Borkmann.
   4  * Subject to the GPL, version 2.
   5  */
   6
   7 #ifndef CURVE_H
   8 #define CURVE_H
   9
  10 #include <stdint.h>
  11 #include <sys/time.h>
  12
  13 #include "locking.h"
  14 #include "built_in.h"
  15 #include "ioops.h"
  16 #include "rnd.h"
  17 #include "taia.h"
  18 #include "crypto.h"
  19
  20 static struct taia tolerance_taia = {
  21         .sec.x = 0,
  22         .nano = 700000000ULL,
  23         .atto = 0,
  24 };
  25
  26 struct curve25519_proto {
  27         unsigned char enonce[crypto_box_noncebytes] __aligned_16;
  28         unsigned char dnonce[crypto_box_noncebytes] __aligned_16;
  29         unsigned char key[crypto_box_noncebytes] __aligned_16;
  30 };
  31
  32 struct curve25519_struct {
  33         unsigned char *enc_buf;
  34         unsigned char *dec_buf;
  35         size_t enc_buf_size;
  36         size_t dec_buf_size;
  37         struct spinlock enc_lock;
  38         struct spinlock dec_lock;
  39 };
  40
  41 extern void curve25519_selftest(void);
  42 extern void curve25519_alloc_or_maybe_die(struct curve25519_struct *curve);
  43 extern void curve25519_free(void *curve);
  44 extern int curve25519_pubkey_hexparse_32(unsigned char *bin, size_t blen, const char *ascii, size_t alen);
  45 extern int curve25519_proto_init(struct curve25519_proto *proto, unsigned char *pubkey_remote, size_t len,
  46                                  char *home, int server);
  47 extern ssize_t curve25519_encode(struct curve25519_struct *curve, struct curve25519_proto *proto,
  48                                  unsigned char *plaintext, size_t size, unsigned char **chipertext);
  49 extern ssize_t curve25519_decode(struct curve25519_struct *curve, struct curve25519_proto *proto,
  50                                  unsigned char *chipertext, size_t size, unsigned char **plaintext,
  51                                  struct taia *arrival_taia);
  52
  53 static inline int is_good_taia(struct taia *arrival_taia, struct taia *packet_taia)
  54 {
  55         int is_ts_good = 0;
  56         struct taia sub_res;
  57
  58         if (taia_less(arrival_taia, packet_taia)) {
  59                 taia_sub(&sub_res, packet_taia, arrival_taia);
  60                 if (taia_less(&sub_res, &tolerance_taia))
  61                         is_ts_good = 1;
  62                 else
  63                         is_ts_good = 0;
  64         } else {
  65                 taia_sub(&sub_res, arrival_taia, packet_taia);
  66                 if (taia_less(&sub_res, &tolerance_taia))
  67                         is_ts_good = 1;
  68                 else
  69                         is_ts_good = 0;
  70         }
  71
  72         return is_ts_good;
  73 }
  74
  75 #endif /* CURVE_H */