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 */