src/feature/dircommon/consdiff.h

   1 /* Copyright (c) 2014, Daniel Martí
   2  * Copyright (c) 2014-2021, The Tor Project, Inc. */
   3 /* See LICENSE for licensing information */
   4
   5 /**
   6  * @file consdiff.h
   7  * @brief Header for consdiff.c
   8  **/
   9
  10 #ifndef TOR_CONSDIFF_H
  11 #define TOR_CONSDIFF_H
  12
  13 #include "core/or/or.h"
  14
  15 char *consensus_diff_generate(const char *cons1, size_t cons1len,
  16                               const char *cons2, size_t cons2len);
  17 char *consensus_diff_apply(const char *consensus, size_t consensus_len,
  18                            const char *diff, size_t diff_len);
  19
  20 int looks_like_a_consensus_diff(const char *document, size_t len);
  21
  22 #ifdef CONSDIFF_PRIVATE
  23 #include "lib/container/bitarray.h"
  24
  25 struct memarea_t;
  26
  27 /** Line type used for constructing consensus diffs.  Each of these lines
  28  * refers to a chunk of memory allocated elsewhere, and is not necessarily
  29  * NUL-terminated: this helps us avoid copies and save memory. */
  30 typedef struct cdline_t {
  31   const char *s;
  32   uint32_t len;
  33 } cdline_t;
  34
  35 typedef struct consensus_digest_t {
  36   uint8_t sha3_256[DIGEST256_LEN];
  37 } consensus_digest_t;
  38
  39 STATIC smartlist_t *consdiff_gen_diff(const smartlist_t *cons1,
  40                                       const smartlist_t *cons2,
  41                                       const consensus_digest_t *digests1,
  42                                       const consensus_digest_t *digests2,
  43                                       struct memarea_t *area);
  44 STATIC char *consdiff_apply_diff(const smartlist_t *cons1,
  45                                  const smartlist_t *diff,
  46                                  const consensus_digest_t *digests1);
  47 STATIC int consdiff_get_digests(const smartlist_t *diff,
  48                                 char *digest1_out,
  49                                 char *digest2_out);
  50
  51 /** Data structure to define a slice of a smarltist. */
  52 typedef struct smartlist_slice_t {
  53   /**
  54    * Smartlist that this slice is made from.
  55    * References the whole original smartlist that the slice was made out of.
  56    * */
  57   const smartlist_t *list;
  58   /** Starting position of the slice in the smartlist. */
  59   int offset;
  60   /** Length of the slice, i.e. the number of elements it holds. */
  61   int len;
  62 } smartlist_slice_t;
  63 STATIC smartlist_t *gen_ed_diff(const smartlist_t *cons1,
  64                                 const smartlist_t *cons2,
  65                                 struct memarea_t *area);
  66 STATIC smartlist_t *apply_ed_diff(const smartlist_t *cons1,
  67                                   const smartlist_t *diff,
  68                                   int start_line);
  69 STATIC void calc_changes(smartlist_slice_t *slice1, smartlist_slice_t *slice2,
  70                          bitarray_t *changed1, bitarray_t *changed2);
  71 STATIC smartlist_slice_t *smartlist_slice(const smartlist_t *list,
  72                                           int start, int end);
  73 STATIC int next_router(const smartlist_t *cons, int cur);
  74 STATIC int *lcs_lengths(const smartlist_slice_t *slice1,
  75                         const smartlist_slice_t *slice2,
  76                         int direction);
  77 STATIC void trim_slices(smartlist_slice_t *slice1, smartlist_slice_t *slice2);
  78 STATIC int base64cmp(const cdline_t *hash1, const cdline_t *hash2);
  79 STATIC int get_id_hash(const cdline_t *line, cdline_t *hash_out);
  80 STATIC int is_valid_router_entry(const cdline_t *line);
  81 STATIC int smartlist_slice_string_pos(const smartlist_slice_t *slice,
  82                                       const cdline_t *string);
  83 STATIC void set_changed(bitarray_t *changed1, bitarray_t *changed2,
  84                         const smartlist_slice_t *slice1,
  85                         const smartlist_slice_t *slice2);
  86 STATIC int consensus_split_lines(smartlist_t *out,
  87                                  const char *s, size_t len,
  88                                  struct memarea_t *area);
  89 STATIC void smartlist_add_linecpy(smartlist_t *lst, struct memarea_t *area,
  90                                   const char *s);
  91 STATIC int lines_eq(const cdline_t *a, const cdline_t *b);
  92 STATIC int line_str_eq(const cdline_t *a, const char *b);
  93
  94 MOCK_DECL(STATIC int,
  95           consensus_compute_digest,(const char *cons, size_t len,
  96                                     consensus_digest_t *digest_out));
  97 MOCK_DECL(STATIC int,
  98           consensus_compute_digest_as_signed,(const char *cons, size_t len,
  99                                               consensus_digest_t *digest_out));
 100 MOCK_DECL(STATIC int,
 101           consensus_digest_eq,(const uint8_t *d1,
 102                                const uint8_t *d2));
 103 #endif /* defined(CONSDIFF_PRIVATE) */
 104
 105 #endif /* !defined(TOR_CONSDIFF_H) */