1 | /* Network-related functions for internal library use. |
2 | Copyright (C) 2016-2017 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 | <http://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 | |
27 | int __inet6_scopeid_pton (const struct in6_addr *address, |
28 | const char *scope, uint32_t *result); |
29 | libc_hidden_proto (__inet6_scopeid_pton) |
30 | |
31 | |
32 | /* Deadline handling for enforcing timeouts. |
33 | |
34 | Code should call __deadline_current_time to obtain the current time |
35 | and cache it locally. The cache needs updating after every |
36 | long-running or potentially blocking operation. Deadlines relative |
37 | to the current time can be computed using __deadline_from_timeval. |
38 | The deadlines may have to be recomputed in response to certain |
39 | events (such as an incoming packet), but they are absolute (not |
40 | relative to the current time). A timeout suitable for use with the |
41 | poll function can be computed from such a deadline using |
42 | __deadline_to_ms. |
43 | |
44 | The fields in the structs defined belowed should only be used |
45 | within the implementation. */ |
46 | |
47 | /* Cache of the current time. Used to compute deadlines from relative |
48 | timeouts and vice versa. */ |
49 | struct deadline_current_time |
50 | { |
51 | struct timespec current; |
52 | }; |
53 | |
54 | /* Return the current time. Terminates the process if the current |
55 | time is not available. */ |
56 | struct deadline_current_time __deadline_current_time (void) |
57 | internal_function attribute_hidden; |
58 | |
59 | /* Computed absolute deadline. */ |
60 | struct deadline |
61 | { |
62 | struct timespec absolute; |
63 | }; |
64 | |
65 | |
66 | /* For internal use only. */ |
67 | static inline bool |
68 | __deadline_is_infinite (struct deadline deadline) |
69 | { |
70 | return deadline.absolute.tv_nsec < 0; |
71 | } |
72 | |
73 | /* Return true if the current time is at the deadline or past it. */ |
74 | static inline bool |
75 | __deadline_elapsed (struct deadline_current_time current, |
76 | struct deadline deadline) |
77 | { |
78 | return !__deadline_is_infinite (deadline) |
79 | && (current.current.tv_sec > deadline.absolute.tv_sec |
80 | || (current.current.tv_sec == deadline.absolute.tv_sec |
81 | && current.current.tv_nsec >= deadline.absolute.tv_nsec)); |
82 | } |
83 | |
84 | /* Return the deadline which occurs first. */ |
85 | static inline struct deadline |
86 | __deadline_first (struct deadline left, struct deadline right) |
87 | { |
88 | if (__deadline_is_infinite (right) |
89 | || left.absolute.tv_sec < right.absolute.tv_sec |
90 | || (left.absolute.tv_sec == right.absolute.tv_sec |
91 | && left.absolute.tv_nsec < right.absolute.tv_nsec)) |
92 | return left; |
93 | else |
94 | return right; |
95 | } |
96 | |
97 | /* Add TV to the current time and return it. Returns a special |
98 | infinite absolute deadline on overflow. */ |
99 | struct deadline __deadline_from_timeval (struct deadline_current_time, |
100 | struct timeval tv) |
101 | internal_function attribute_hidden; |
102 | |
103 | /* Compute the number of milliseconds until the specified deadline, |
104 | from the current time in the argument. The result is mainly for |
105 | use with poll. If the deadline has already passed, return 0. If |
106 | the result would overflow an int, return INT_MAX. */ |
107 | int __deadline_to_ms (struct deadline_current_time, struct deadline) |
108 | internal_function attribute_hidden; |
109 | |
110 | /* Return true if TV.tv_sec is non-negative and TV.tv_usec is in the |
111 | interval [0, 999999]. */ |
112 | static inline bool |
113 | __is_timeval_valid_timeout (struct timeval tv) |
114 | { |
115 | return tv.tv_sec >= 0 && tv.tv_usec >= 0 && tv.tv_usec < 1000 * 1000; |
116 | } |
117 | |
118 | #endif /* _NET_INTERNAL_H */ |
119 | |