mdw@git.distorted.org.uk Git - secnet/blob - util.h

   1 /*
   2  * This file is part of secnet.
   3  * See README for full list of copyright holders.
   4  *
   5  * secnet is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 3 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * secnet is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * version 3 along with secnet; if not, see
  17  * https://www.gnu.org/licenses/gpl.html.
  18  */
  19
  20 #ifndef util_h
  21 #define util_h
  22
  23 #include "secnet.h"
  24 #include <gmp.h>
  25
  26 #include "hackypar.h"
  27
  28 #define BUF_ASSERT_FREE(buf) do { buffer_assert_free((buf), \
  29                                                      __FILE__,__LINE__); } \
  30 while(0)
  31 #define BUF_ASSERT_USED(buf) do { buffer_assert_used((buf), \
  32                                                      __FILE__,__LINE__); } \
  33 while(0)
  34 #define BUF_ALLOC(buf,own) do { buffer_assert_free((buf),__FILE__,__LINE__); \
  35          (buf)->free=False; (buf)->owner=(own); (buf)->start=(buf)->base; \
  36          (buf)->size=0; } while(0)
  37 #define BUF_FREE(buf) do { (buf)->free=True; } while(0)
  38
  39 extern void buffer_assert_free(struct buffer_if *buffer, cstring_t file,
  40                                int line);
  41 extern void buffer_assert_used(struct buffer_if *buffer, cstring_t file,
  42                                int line);
  43 extern void buffer_new(struct buffer_if *buffer, int32_t len);
  44 extern void buffer_init(struct buffer_if *buffer, int32_t max_start_pad);
  45 extern void buffer_destroy(struct buffer_if *buffer);
  46 extern void buffer_copy(struct buffer_if *dst, const struct buffer_if *src);
  47 extern void *buf_append(struct buffer_if *buf, int32_t amount);
  48 extern void *buf_prepend(struct buffer_if *buf, int32_t amount);
  49 extern void *buf_unappend(struct buffer_if *buf, int32_t amount);
  50 extern void *buf_unprepend(struct buffer_if *buf, int32_t amount);
  51
  52 /*
  53  * void BUF_ADD_BYTES(append,    struct buffer_if*, const void*, int32_t size);
  54  * void BUF_ADD_BYTES(prepend,   struct buffer_if*, const void*, int32_t size);
  55  * void BUF_GET_BYTES(unappend,  struct buffer_if*,       void*, int32_t size);
  56  * void BUF_GET_BYTES(unprepend, struct buffer_if*,       void*, int32_t size);
  57  *     // all of these evaluate size twice
  58  *
  59  * void BUF_ADD_OBJ(append,    struct_buffer_if*, const OBJECT& something);
  60  * void BUF_ADD_OBJ(prepend,   struct_buffer_if*, const OBJECT& something);
  61  * void BUF_GET_OBJ(unappend,  struct_buffer_if*,       OBJECT& something);
  62  * void BUF_GET_OBJ(unprepend, struct_buffer_if*,       OBJECT& something);
  63  */
  64 #define BUF_ADD_BYTES(appendprepend, bufp, datap, size)                 \
  65     (buf_un##appendprepend /* ensures we have correct direction */,     \
  66      memcpy(buf_##appendprepend((bufp),(size)),(datap),(size)))
  67 #define BUF_ADD_OBJ(appendprepend, bufp, obj) \
  68     BUF_ADD_BYTES(appendprepend,(bufp),&(obj),sizeof((obj)))
  69 #define BUF_GET_BYTES(unappendunprepend, bufp, datap, size)             \
  70     (BUF_GET__DOESNOTEXIST__buf_un##unappendunprepend,                  \
  71      memcpy((datap),buf_##unappendunprepend((bufp),(size)),(size)))
  72 #define BUF_GET_OBJ(unappendunprepend, bufp, obj) \
  73     BUF_ADD_BYTES(unappendunprepend,&(obj),(bufp),sizeof((obj)))
  74 #define BUF_GET__DOESNOTEXIST__buf_ununappend  0
  75 #define BUF_GET__DOESNOTEXIST__buf_ununprepend 0
  76
  77 static inline int32_t buf_remaining_space(const struct buffer_if *buf)
  78 {
  79     return (buf->base + buf->alloclen) - (buf->start + buf->size);
  80 }
  81
  82 extern void buffer_readonly_view(struct buffer_if *n, const void*, int32_t len);
  83 extern void buffer_readonly_clone(struct buffer_if *n, const struct buffer_if*);
  84   /* Caller must only use unappend, unprepend et al. on n.
  85    * New buffer state (in n) before this can be undefined.  After use,
  86    * it must NOT be freed. */
  87
  88 extern void buf_append_string(struct buffer_if *buf, cstring_t s);
  89   /* Append a two-byte length and the string to the buffer. Length is in
  90    * network byte order. */
  91
  92 extern string_t hex_encode(const uint8_t *bin, int binsize);
  93   /* Convert a byte array to hex, returning the result in a freshly allocated
  94    * string. */
  95
  96 extern bool_t hex_decode(uint8_t *buffer, int32_t buflen, int32_t *outlen,
  97                          cstring_t hb, bool_t allow_odd_nibble);
  98   /* Convert a hex string to binary, storing the result in buffer.  If
  99    * allow_odd_nibble then it is acceptable if the input is an odd number of
 100    * digits, and an additional leading zero digit is assumed; otherwise, this
 101    * is not acceptable and the conversion fails.
 102    *
 103    * The input is processed left to right until it is consumed, the buffer is
 104    * full, or an error is encountered in the input.  The length of output
 105    * produced is stored in *outlen.  Returns true if the entire input was
 106    * processed without error; otherwise false. */
 107
 108 extern void read_mpbin(MP_INT *a, uint8_t *bin, int binsize);
 109   /* Convert a buffer into its MP_INT representation */
 110
 111 extern char *write_mpstring(MP_INT *a);
 112   /* Convert a MP_INT into a hex string */
 113
 114 extern int32_t write_mpbin(MP_INT *a, uint8_t *buffer, int32_t buflen);
 115   /* Convert a MP_INT into a buffer; return length; truncate if necessary */
 116
 117 extern struct log_if *init_log(list_t *loglist);
 118
 119 extern void send_nak(const struct comm_addr *dest, uint32_t our_index,
 120                      uint32_t their_index, uint32_t msgtype,
 121                      struct buffer_if *buf, const char *logwhy);
 122
 123 extern int consttime_memeq(const void *s1, const void *s2, size_t n);
 124
 125 const char *iaddr_to_string(const union iaddr *ia);
 126 int iaddr_socklen(const union iaddr *ia);
 127
 128 void string_item_to_iaddr(const item_t *item, uint16_t port, union iaddr *ia,
 129                           const char *desc);
 130
 131
 132 /*
 133  * SBUF_DEFINE(int nbufs, size_t size);
 134  *   // Generates a number of definitions and statements organising
 135  *   // nbufs rotating char[size] buffers such that subsequent code
 136  *   // may refer to:
 137  * char *const SBUF;
 138  */
 139 #define SBUF_DEFINE(nbufs, size)                        \
 140     static int static_bufs__bufnum;                     \
 141     static char static_bufs__bufs[(nbufs)][(size)];     \
 142     static_bufs__bufnum++;                              \
 143     static_bufs__bufnum %= (nbufs);                     \
 144     static_bufs__bufs[static_bufs__bufnum]
 145 #define SBUF (static_bufs__bufs[static_bufs__bufnum])
 146
 147 /*----- line-buffered asynch input -----*/
 148
 149 enum async_linebuf_result {
 150     async_linebuf_nothing,
 151     async_linebuf_ok,
 152     async_linebuf_eof,
 153     async_linebuf_broken,
 154 };
 155
 156 const char *pollbadbit(int revents); /* returns 0, or bad bit description */
 157
 158 enum async_linebuf_result
 159 async_linebuf_read(struct pollfd *pfd, struct buffer_if *buf,
 160                    const char **emsg_out);
 161    /* Implements reading whole lines, asynchronously.  Use like
 162     * this:
 163     *   - set up the fd, which should be readable, O_NONBLOCK
 164     *   - set up and initialise buffer, which should be big enough
 165     *     for one line plus its trailing newline, and be empty
 166     *     with start==base
 167     *   - in your beforepoll_fn, be interested in POLLIN
 168     *   - in your afterpoll_fn, repeatedly call this function
 169     *     until it doesn't return `nothing'
 170     *   - after you're done, simply close fd and free or reset buf
 171     * State on return from async_linebuf_read depends on return value:
 172     *
 173     *   async_linebuf_nothing:
 174     *
 175     *      No complete lines available right now.  You should return
 176     *      from afterpoll.  buf should be left untouched until the
 177     *      next call to async_linebuf_read.
 178     *
 179     *   async_linebuf_ok:
 180     *
 181     *      buf->base contains a input line as a nul-terminated string
 182     *      (\n replaced by \0); *emsg_out==0.  You must call
 183     *      async_linebuf_read again before returning from afterpoll.
 184     *
 185     *   async_linebuf_eof:
 186     *
 187     *      EOF on stream.  buf->base contains any partial
 188     *      (non-newline-terminated) line; *emsg_out!=0 iff there was
 189     *      such a partial line.  You can call async_linebuf_read again
 190     *      if you like but it will probably just return eof again.
 191     *
 192     *   broken:
 193     *
 194     *      Fatal problem (might be overly long lines, nuls in input
 195     *      data, bad bits in pfd->revents, errors from read, etc.)
 196     *
 197     *      *emsg_out is the error message describing the problem;
 198     *      this message might be stored in buf, might be from
 199     *      strerror, or might be a constant.
 200     *
 201     *      You must not call async_linebuf_read again.  buf contents
 202     *      is undefined: it is only safe to reset or free.
 203     *
 204     * While using this function, do not look at buf->start or ->size
 205     * or anything after the first '\0' in buf.
 206     *
 207     * If you decide to stop reading with async_linebuf_read that's
 208     * fine and you can reset or free buf, but you risk missing some
 209     * read-but-not-reported data.
 210     */
 211
 212 /*----- some handy macros -----*/
 213
 214 #define MINMAX(ae,be,op) ({                     \
 215         typeof((ae)) a=(ae);                    \
 216         typeof((be)) b=(be);                    \
 217         a op b ? a : b;                         \
 218     })
 219 #define MAX(a,b) MINMAX((a),(b),>)
 220 #define MIN(a,b) MINMAX((a),(b),<)
 221
 222 #define MAX_RAW(a,b) ((a)>(b)?(a):(b))
 223 #define MIN_RAW(a,b) ((a)<(b)?(a):(b))
 224
 225 static inline bool_t iswouldblock(int e)
 226     { return e==EWOULDBLOCK || e==EAGAIN; }
 227
 228 #endif /* util_h */