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 static inline int hex_encode_size(int binsize) { return binsize*2 + 1; }
  93 extern void hex_encode(const uint8_t *bin, int binsize, char *buf);
  94   /* Convert a byte array to hex into a supplied buffer. */
  95 extern string_t hex_encode_alloc(const uint8_t *bin, int binsize);
  96   /* Returns the result in a freshly allocated string. */
  97
  98 extern bool_t hex_decode(uint8_t *buffer, int32_t buflen, int32_t *outlen,
  99                          cstring_t hb, bool_t allow_odd_nibble);
 100   /* Convert a hex string to binary, storing the result in buffer.  If
 101    * allow_odd_nibble then it is acceptable if the input is an odd number of
 102    * digits, and an additional leading zero digit is assumed; otherwise, this
 103    * is not acceptable and the conversion fails.
 104    *
 105    * The input is processed left to right until it is consumed, the buffer is
 106    * full, or an error is encountered in the input.  The length of output
 107    * produced is stored in *outlen.  Returns true if the entire input was
 108    * processed without error; otherwise false. */
 109
 110 extern void read_mpbin(MP_INT *a, uint8_t *bin, int binsize);
 111   /* Convert a buffer into its MP_INT representation */
 112
 113 extern char *write_mpstring(MP_INT *a);
 114   /* Convert a MP_INT into a hex string */
 115
 116 extern int32_t write_mpbin(MP_INT *a, uint8_t *buffer, int32_t buflen);
 117   /* Convert a MP_INT into a buffer; return length; truncate if necessary */
 118
 119 extern struct log_if *init_log(list_t *loglist);
 120
 121 extern void send_nak(const struct comm_addr *dest, uint32_t our_index,
 122                      uint32_t their_index, uint32_t msgtype,
 123                      struct buffer_if *buf, const char *logwhy);
 124
 125 extern int consttime_memeq(const void *s1, const void *s2, size_t n);
 126
 127 const char *iaddr_to_string(const union iaddr *ia);
 128 int iaddr_socklen(const union iaddr *ia);
 129
 130 void string_item_to_iaddr(const item_t *item, uint16_t port, union iaddr *ia,
 131                           const char *desc);
 132
 133
 134 /*
 135  * SBUF_DEFINE(int nbufs, size_t size);
 136  *   // Generates a number of definitions and statements organising
 137  *   // nbufs rotating char[size] buffers such that subsequent code
 138  *   // may refer to:
 139  * char *const SBUF;
 140  */
 141 #define SBUF_DEFINE(nbufs, size)                        \
 142     static int static_bufs__bufnum;                     \
 143     static char static_bufs__bufs[(nbufs)][(size)];     \
 144     static_bufs__bufnum++;                              \
 145     static_bufs__bufnum %= (nbufs);                     \
 146     static_bufs__bufs[static_bufs__bufnum]
 147 #define SBUF (static_bufs__bufs[static_bufs__bufnum])
 148
 149 /*----- line-buffered asynch input -----*/
 150
 151 enum async_linebuf_result {
 152     async_linebuf_nothing,
 153     async_linebuf_ok,
 154     async_linebuf_eof,
 155     async_linebuf_broken,
 156 };
 157
 158 const char *pollbadbit(int revents); /* returns 0, or bad bit description */
 159
 160 enum async_linebuf_result
 161 async_linebuf_read(struct pollfd *pfd, struct buffer_if *buf,
 162                    const char **emsg_out);
 163    /* Implements reading whole lines, asynchronously.  Use like
 164     * this:
 165     *   - set up the fd, which should be readable, O_NONBLOCK
 166     *   - set up and initialise buffer, which should be big enough
 167     *     for one line plus its trailing newline, and be empty
 168     *     with start==base
 169     *   - in your beforepoll_fn, be interested in POLLIN
 170     *   - in your afterpoll_fn, repeatedly call this function
 171     *     until it doesn't return `nothing'
 172     *   - after you're done, simply close fd and free or reset buf
 173     * State on return from async_linebuf_read depends on return value:
 174     *
 175     *   async_linebuf_nothing:
 176     *
 177     *      No complete lines available right now.  You should return
 178     *      from afterpoll.  buf should be left untouched until the
 179     *      next call to async_linebuf_read.
 180     *
 181     *   async_linebuf_ok:
 182     *
 183     *      buf->base contains a input line as a nul-terminated string
 184     *      (\n replaced by \0); *emsg_out==0.  You must call
 185     *      async_linebuf_read again before returning from afterpoll.
 186     *
 187     *   async_linebuf_eof:
 188     *
 189     *      EOF on stream.  buf->base contains any partial
 190     *      (non-newline-terminated) line; *emsg_out!=0 iff there was
 191     *      such a partial line.  You can call async_linebuf_read again
 192     *      if you like but it will probably just return eof again.
 193     *
 194     *   broken:
 195     *
 196     *      Fatal problem (might be overly long lines, nuls in input
 197     *      data, bad bits in pfd->revents, errors from read, etc.)
 198     *
 199     *      *emsg_out is the error message describing the problem;
 200     *      this message might be stored in buf, might be from
 201     *      strerror, or might be a constant.
 202     *
 203     *      You must not call async_linebuf_read again.  buf contents
 204     *      is undefined: it is only safe to reset or free.
 205     *
 206     * While using this function, do not look at buf->start or ->size
 207     * or anything after the first '\0' in buf.
 208     *
 209     * If you decide to stop reading with async_linebuf_read that's
 210     * fine and you can reset or free buf, but you risk missing some
 211     * read-but-not-reported data.
 212     */
 213
 214 /*----- some handy macros -----*/
 215
 216 #define MINMAX(ae,be,op) ({                     \
 217         typeof((ae)) a=(ae);                    \
 218         typeof((be)) b=(be);                    \
 219         a op b ? a : b;                         \
 220     })
 221 #define MAX(a,b) MINMAX((a),(b),>)
 222 #define MIN(a,b) MINMAX((a),(b),<)
 223
 224 #define MAX_RAW(a,b) ((a)>(b)?(a):(b))
 225 #define MIN_RAW(a,b) ((a)<(b)?(a):(b))
 226
 227 static inline bool_t iswouldblock(int e)
 228     { return e==EWOULDBLOCK || e==EAGAIN; }
 229
 230 #endif /* util_h */