lib/network.h

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Network library header.
   4  * Copyright (C) 1998 Kunihiro Ishiguro
   5  */
   6
   7 #ifndef _ZEBRA_NETWORK_H
   8 #define _ZEBRA_NETWORK_H
   9
  10 #ifdef HAVE_SYS_ENDIAN_H
  11 #include <sys/endian.h>
  12 #endif
  13 #ifdef HAVE_ENDIAN_H
  14 #include <endian.h>
  15 #endif
  16
  17 #ifdef __cplusplus
  18 extern "C" {
  19 #endif
  20
  21 /* Both readn and writen are deprecated and will be removed.  They are not
  22    suitable for use with non-blocking file descriptors.
  23  */
  24 extern int readn(int, uint8_t *, int);
  25 extern int writen(int, const uint8_t *, int);
  26
  27 /* Set the file descriptor to use non-blocking I/O.  Returns 0 for success,
  28    -1 on error. */
  29 extern int set_nonblocking(int fd);
  30
  31 extern int set_cloexec(int fd);
  32
  33 /* Does the I/O error indicate that the operation should be retried later? */
  34 #define ERRNO_IO_RETRY(EN)                                                     \
  35         (((EN) == EAGAIN) || ((EN) == EWOULDBLOCK) || ((EN) == EINTR))
  36
  37 extern float htonf(float);
  38 extern float ntohf(float);
  39
  40 /* force type for be64toh/htobe64 to be uint64_t, *without* a direct cast
  41  *
  42  * this is a workaround for false-positive printfrr warnings from FRR's
  43  * frr-format GCC plugin that would be triggered from
  44  * { printfrr("%"PRIu64, (uint64_t)be64toh(...)); }
  45  *
  46  * the key element here is that "(uint64_t)expr" causes the warning, while
  47  * "({ uint64_t x = expr; x; })" does not.  (The cast is the trigger, a
  48  * variable of the same type works correctly.)
  49  */
  50
  51 /* zap system definitions... */
  52 #ifdef be64toh
  53 #undef be64toh
  54 #endif
  55 #ifdef htobe64
  56 #undef htobe64
  57 #endif
  58
  59 #if BYTE_ORDER == LITTLE_ENDIAN
  60 #define be64toh(x)      ({ uint64_t r = __builtin_bswap64(x); r; })
  61 #define htobe64(x)      ({ uint64_t r = __builtin_bswap64(x); r; })
  62 #elif BYTE_ORDER == BIG_ENDIAN
  63 #define be64toh(x)      ({ uint64_t r = (x); r; })
  64 #define htobe64(x)      ({ uint64_t r = (x); r; })
  65 #else
  66 #error nobody expects the endianish inquisition. check OS endian.h headers.
  67 #endif
  68
  69 /**
  70  * Generate a sequence number using monotonic clock with a same second call
  71  * protection to help guarantee a unique incremental sequence number that never
  72  * goes back (except when wrapping/overflow).
  73  *
  74  * **NOTE** this function is not thread safe since it uses `static` variable.
  75  *
  76  * This function and `frr_sequence32_next` should be used to initialize
  77  * sequence numbers without directly calling other `time_t` returning
  78  * functions because of `time_t` truncation warnings.
  79  *
  80  * \returns `uint64_t` number based on the monotonic clock.
  81  */
  82 extern uint64_t frr_sequence_next(void);
  83
  84 /** Same as `frr_sequence_next` but returns truncated number. */
  85 extern uint32_t frr_sequence32_next(void);
  86
  87 /**
  88  * Helper function that returns a random long value. The main purpose of
  89  * this function is to hide a `random()` call that gets flagged by coverity
  90  * scan and put it into one place.
  91  *
  92  * The main usage of this function should be for generating jitter or weak
  93  * random values for simple purposes.
  94  *
  95  * See 'man 3 random' for more information.
  96  *
  97  * \returns random long integer.
  98  */
  99 static inline long frr_weak_random(void)
 100 {
 101         /* coverity[dont_call] */
 102         return random();
 103 }
 104
 105 #ifdef __cplusplus
 106 }
 107 #endif
 108
 109 #endif /* _ZEBRA_NETWORK_H */