Commit | Line | Data |
---|---|---|
28fbcfa0 AS |
1 | /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com |
2 | * | |
3 | * This program is free software; you can redistribute it and/or | |
4 | * modify it under the terms of version 2 of the GNU General Public | |
5 | * License as published by the Free Software Foundation. | |
6 | * | |
7 | * This program is distributed in the hope that it will be useful, but | |
8 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
9 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
10 | * General Public License for more details. | |
11 | */ | |
12 | #include <linux/bpf.h> | |
13 | #include <linux/err.h> | |
14 | #include <linux/vmalloc.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/mm.h> | |
17 | ||
18 | struct bpf_array { | |
19 | struct bpf_map map; | |
20 | u32 elem_size; | |
21 | char value[0] __aligned(8); | |
22 | }; | |
23 | ||
24 | /* Called from syscall */ | |
25 | static struct bpf_map *array_map_alloc(union bpf_attr *attr) | |
26 | { | |
27 | struct bpf_array *array; | |
daaf427c | 28 | u32 elem_size, array_size; |
28fbcfa0 AS |
29 | |
30 | /* check sanity of attributes */ | |
31 | if (attr->max_entries == 0 || attr->key_size != 4 || | |
32 | attr->value_size == 0) | |
33 | return ERR_PTR(-EINVAL); | |
34 | ||
35 | elem_size = round_up(attr->value_size, 8); | |
36 | ||
daaf427c AS |
37 | /* check round_up into zero and u32 overflow */ |
38 | if (elem_size == 0 || | |
39 | attr->max_entries > (U32_MAX - sizeof(*array)) / elem_size) | |
40 | return ERR_PTR(-ENOMEM); | |
41 | ||
42 | array_size = sizeof(*array) + attr->max_entries * elem_size; | |
43 | ||
28fbcfa0 | 44 | /* allocate all map elements and zero-initialize them */ |
daaf427c | 45 | array = kzalloc(array_size, GFP_USER | __GFP_NOWARN); |
28fbcfa0 | 46 | if (!array) { |
daaf427c | 47 | array = vzalloc(array_size); |
28fbcfa0 AS |
48 | if (!array) |
49 | return ERR_PTR(-ENOMEM); | |
50 | } | |
51 | ||
52 | /* copy mandatory map attributes */ | |
53 | array->map.key_size = attr->key_size; | |
54 | array->map.value_size = attr->value_size; | |
55 | array->map.max_entries = attr->max_entries; | |
56 | ||
57 | array->elem_size = elem_size; | |
58 | ||
59 | return &array->map; | |
28fbcfa0 AS |
60 | } |
61 | ||
62 | /* Called from syscall or from eBPF program */ | |
63 | static void *array_map_lookup_elem(struct bpf_map *map, void *key) | |
64 | { | |
65 | struct bpf_array *array = container_of(map, struct bpf_array, map); | |
66 | u32 index = *(u32 *)key; | |
67 | ||
68 | if (index >= array->map.max_entries) | |
69 | return NULL; | |
70 | ||
71 | return array->value + array->elem_size * index; | |
72 | } | |
73 | ||
74 | /* Called from syscall */ | |
75 | static int array_map_get_next_key(struct bpf_map *map, void *key, void *next_key) | |
76 | { | |
77 | struct bpf_array *array = container_of(map, struct bpf_array, map); | |
78 | u32 index = *(u32 *)key; | |
79 | u32 *next = (u32 *)next_key; | |
80 | ||
81 | if (index >= array->map.max_entries) { | |
82 | *next = 0; | |
83 | return 0; | |
84 | } | |
85 | ||
86 | if (index == array->map.max_entries - 1) | |
87 | return -ENOENT; | |
88 | ||
89 | *next = index + 1; | |
90 | return 0; | |
91 | } | |
92 | ||
93 | /* Called from syscall or from eBPF program */ | |
94 | static int array_map_update_elem(struct bpf_map *map, void *key, void *value, | |
95 | u64 map_flags) | |
96 | { | |
97 | struct bpf_array *array = container_of(map, struct bpf_array, map); | |
98 | u32 index = *(u32 *)key; | |
99 | ||
100 | if (map_flags > BPF_EXIST) | |
101 | /* unknown flags */ | |
102 | return -EINVAL; | |
103 | ||
104 | if (index >= array->map.max_entries) | |
105 | /* all elements were pre-allocated, cannot insert a new one */ | |
106 | return -E2BIG; | |
107 | ||
108 | if (map_flags == BPF_NOEXIST) | |
daaf427c | 109 | /* all elements already exist */ |
28fbcfa0 AS |
110 | return -EEXIST; |
111 | ||
112 | memcpy(array->value + array->elem_size * index, value, array->elem_size); | |
113 | return 0; | |
114 | } | |
115 | ||
116 | /* Called from syscall or from eBPF program */ | |
117 | static int array_map_delete_elem(struct bpf_map *map, void *key) | |
118 | { | |
119 | return -EINVAL; | |
120 | } | |
121 | ||
122 | /* Called when map->refcnt goes to zero, either from workqueue or from syscall */ | |
123 | static void array_map_free(struct bpf_map *map) | |
124 | { | |
125 | struct bpf_array *array = container_of(map, struct bpf_array, map); | |
126 | ||
127 | /* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0, | |
128 | * so the programs (can be more than one that used this map) were | |
129 | * disconnected from events. Wait for outstanding programs to complete | |
130 | * and free the array | |
131 | */ | |
132 | synchronize_rcu(); | |
133 | ||
134 | kvfree(array); | |
135 | } | |
136 | ||
137 | static struct bpf_map_ops array_ops = { | |
138 | .map_alloc = array_map_alloc, | |
139 | .map_free = array_map_free, | |
140 | .map_get_next_key = array_map_get_next_key, | |
141 | .map_lookup_elem = array_map_lookup_elem, | |
142 | .map_update_elem = array_map_update_elem, | |
143 | .map_delete_elem = array_map_delete_elem, | |
144 | }; | |
145 | ||
146 | static struct bpf_map_type_list tl = { | |
147 | .ops = &array_ops, | |
148 | .type = BPF_MAP_TYPE_ARRAY, | |
149 | }; | |
150 | ||
151 | static int __init register_array_map(void) | |
152 | { | |
153 | bpf_register_map_type(&tl); | |
154 | return 0; | |
155 | } | |
156 | late_initcall(register_array_map); |