inet/net-internal.h

   1 /* Network-related functions for internal library use.
   2    Copyright (C) 2016-2023 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _NET_INTERNAL_H
  20 #define _NET_INTERNAL_H 1
  21
  22 #include <arpa/inet.h>
  23 #include <stdbool.h>
  24 #include <stdint.h>
  25 #include <sys/time.h>
  26 #include <libc-diag.h>
  27 #include <struct___timespec64.h>
  28
  29 int __inet6_scopeid_pton (const struct in6_addr *address,
  30                           const char *scope, uint32_t *result);
  31 libc_hidden_proto (__inet6_scopeid_pton)
  32
  33
  34 /* IDNA conversion.  These functions convert domain names between the
  35    current multi-byte character set and the IDNA encoding.  On
  36    success, the result string is written to *RESULT (which the caller
  37    has to free), and zero is returned.  On error, an EAI_* error code
  38    is returned (see <netdb.h>), and *RESULT is not changed.  */
  39 int __idna_to_dns_encoding (const char *name, char **result);
  40 libc_hidden_proto (__idna_to_dns_encoding)
  41 int __idna_from_dns_encoding (const char *name, char **result);
  42 libc_hidden_proto (__idna_from_dns_encoding)
  43
  44
  45 /* Return value of __idna_name_classify below.  */
  46 enum idna_name_classification
  47 {
  48   idna_name_ascii,          /* No non-ASCII characters.  */
  49   idna_name_nonascii,       /* Non-ASCII characters, no backslash.  */
  50   idna_name_nonascii_backslash, /* Non-ASCII characters with backslash.  */
  51   idna_name_encoding_error, /* Decoding error.  */
  52   idna_name_memory_error,   /* Memory allocation failure.  */
  53   idna_name_error,          /* Other error during decoding.  Check errno.  */
  54 };
  55
  56 /* Check the specified name for non-ASCII characters and backslashes
  57    or encoding errors.  */
  58 enum idna_name_classification __idna_name_classify (const char *name)
  59   attribute_hidden;
  60
  61 /* Deadline handling for enforcing timeouts.
  62
  63    Code should call __deadline_current_time to obtain the current time
  64    and cache it locally.  The cache needs updating after every
  65    long-running or potentially blocking operation.  Deadlines relative
  66    to the current time can be computed using __deadline_from_timeval.
  67    The deadlines may have to be recomputed in response to certain
  68    events (such as an incoming packet), but they are absolute (not
  69    relative to the current time).  A timeout suitable for use with the
  70    poll function can be computed from such a deadline using
  71    __deadline_to_ms.
  72
  73    The fields in the structs defined belowed should only be used
  74    within the implementation.  */
  75
  76 /* Cache of the current time.  Used to compute deadlines from relative
  77    timeouts and vice versa.  */
  78 struct deadline_current_time
  79 {
  80   struct __timespec64 current;
  81 };
  82
  83 /* Return the current time.  Terminates the process if the current
  84    time is not available.  */
  85 struct deadline_current_time __deadline_current_time (void) attribute_hidden;
  86
  87 /* Computed absolute deadline.  */
  88 struct deadline
  89 {
  90   struct __timespec64 absolute;
  91 };
  92
  93
  94 /* For internal use only.  */
  95 static inline bool
  96 __deadline_is_infinite (struct deadline deadline)
  97 {
  98   return deadline.absolute.tv_nsec < 0;
  99 }
 100
 101 /* GCC 8.3 and 9.2 both incorrectly report total_deadline
 102  * (from sunrpc/clnt_udp.c) as maybe-uninitialized when tv_sec is 8 bytes
 103  * (64-bits) wide on 32-bit systems. We have to set -Wmaybe-uninitialized
 104  * here as it won't fix the error in sunrpc/clnt_udp.c.
 105  * A GCC bug has been filed here:
 106  *    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91691
 107  */
 108 DIAG_PUSH_NEEDS_COMMENT;
 109 DIAG_IGNORE_NEEDS_COMMENT (9, "-Wmaybe-uninitialized");
 110
 111 /* Return true if the current time is at the deadline or past it.  */
 112 static inline bool
 113 __deadline_elapsed (struct deadline_current_time current,
 114                     struct deadline deadline)
 115 {
 116   return !__deadline_is_infinite (deadline)
 117     && (current.current.tv_sec > deadline.absolute.tv_sec
 118         || (current.current.tv_sec == deadline.absolute.tv_sec
 119             && current.current.tv_nsec >= deadline.absolute.tv_nsec));
 120 }
 121
 122 /* Return the deadline which occurs first.  */
 123 static inline struct deadline
 124 __deadline_first (struct deadline left, struct deadline right)
 125 {
 126   if (__deadline_is_infinite (right)
 127       || left.absolute.tv_sec < right.absolute.tv_sec
 128       || (left.absolute.tv_sec == right.absolute.tv_sec
 129           && left.absolute.tv_nsec < right.absolute.tv_nsec))
 130     return left;
 131   else
 132     return right;
 133 }
 134
 135 DIAG_POP_NEEDS_COMMENT;
 136
 137 /* Add TV to the current time and return it.  Returns a special
 138    infinite absolute deadline on overflow.  */
 139 struct deadline __deadline_from_timeval (struct deadline_current_time,
 140                                          struct timeval tv) attribute_hidden;
 141
 142 /* Compute the number of milliseconds until the specified deadline,
 143    from the current time in the argument.  The result is mainly for
 144    use with poll.  If the deadline has already passed, return 0.  If
 145    the result would overflow an int, return INT_MAX.  */
 146 int __deadline_to_ms (struct deadline_current_time, struct deadline)
 147   attribute_hidden;
 148
 149 /* Return true if TV.tv_sec is non-negative and TV.tv_usec is in the
 150    interval [0, 999999].  */
 151 static inline bool
 152 __is_timeval_valid_timeout (struct timeval tv)
 153 {
 154   return tv.tv_sec >= 0 && tv.tv_usec >= 0 && tv.tv_usec < 1000 * 1000;
 155 }
 156
 157 #endif /* _NET_INTERNAL_H */