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948def4a | 1 | /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
5f8ba20d JK |
2 | |
3 | #include "bpf-foreign.h" | |
4 | #include "bpf-program.h" | |
5 | #include "cgroup.h" | |
6 | #include "memory-util.h" | |
dedca960 | 7 | #include "missing_magic.h" |
5f8ba20d JK |
8 | #include "mountpoint-util.h" |
9 | #include "set.h" | |
dedca960 | 10 | #include "stat-util.h" |
5f8ba20d JK |
11 | |
12 | typedef struct BPFForeignKey BPFForeignKey; | |
13 | struct BPFForeignKey { | |
14 | uint32_t prog_id; | |
15 | uint32_t attach_type; | |
16 | }; | |
17 | ||
18 | static int bpf_foreign_key_new(uint32_t prog_id, | |
19 | enum bpf_attach_type attach_type, | |
20 | BPFForeignKey **ret) { | |
21 | _cleanup_free_ BPFForeignKey *p = NULL; | |
22 | ||
23 | assert(ret); | |
24 | ||
25 | p = new(BPFForeignKey, 1); | |
26 | if (!p) | |
27 | return log_oom(); | |
28 | ||
29 | *p = (BPFForeignKey) { | |
30 | .prog_id = prog_id, | |
31 | .attach_type = attach_type, | |
32 | }; | |
33 | ||
34 | *ret = TAKE_PTR(p); | |
35 | ||
36 | return 0; | |
37 | } | |
38 | ||
39 | static int bpf_foreign_key_compare_func(const BPFForeignKey *a, const BPFForeignKey *b) { | |
40 | int r = CMP(a->prog_id, b->prog_id); | |
41 | if (r != 0) | |
42 | return r; | |
43 | ||
44 | return CMP(a->attach_type, b->attach_type); | |
45 | } | |
46 | ||
47 | static void bpf_foreign_key_hash_func(const BPFForeignKey *p, struct siphash *h) { | |
48 | siphash24_compress(&p->prog_id, sizeof(p->prog_id), h); | |
49 | siphash24_compress(&p->attach_type, sizeof(p->attach_type), h); | |
50 | } | |
51 | ||
52 | DEFINE_PRIVATE_HASH_OPS_FULL(bpf_foreign_by_key_hash_ops, | |
53 | BPFForeignKey, bpf_foreign_key_hash_func, bpf_foreign_key_compare_func, free, | |
76dc1725 | 54 | BPFProgram, bpf_program_free); |
5f8ba20d JK |
55 | |
56 | static int attach_programs(Unit *u, const char *path, Hashmap* foreign_by_key, uint32_t attach_flags) { | |
57 | const BPFForeignKey *key; | |
58 | BPFProgram *prog; | |
59 | int r; | |
60 | ||
61 | assert(u); | |
62 | ||
63 | HASHMAP_FOREACH_KEY(prog, key, foreign_by_key) { | |
64 | r = bpf_program_cgroup_attach(prog, key->attach_type, path, attach_flags); | |
65 | if (r < 0) | |
b1acbc08 | 66 | return log_unit_error_errno(u, r, "bpf-foreign: Attaching foreign BPF program to cgroup %s failed: %m", path); |
5f8ba20d JK |
67 | } |
68 | ||
69 | return 0; | |
70 | } | |
71 | ||
72 | /* | |
73 | * Prepare foreign BPF program for installation: | |
74 | * - Load the program from BPF filesystem to the kernel; | |
75 | * - Store program FD identified by program ID and attach type in the unit. | |
76 | */ | |
77 | static int bpf_foreign_prepare( | |
78 | Unit *u, | |
79 | enum bpf_attach_type attach_type, | |
80 | const char *bpffs_path) { | |
76dc1725 | 81 | _cleanup_(bpf_program_freep) BPFProgram *prog = NULL; |
5f8ba20d JK |
82 | _cleanup_free_ BPFForeignKey *key = NULL; |
83 | uint32_t prog_id; | |
84 | int r; | |
85 | ||
86 | assert(u); | |
87 | assert(bpffs_path); | |
88 | ||
dedca960 JK |
89 | r = path_is_fs_type(bpffs_path, BPF_FS_MAGIC); |
90 | if (r < 0) | |
91 | return log_unit_error_errno(u, r, | |
b1acbc08 | 92 | "bpf-foreign: Failed to determine filesystem type of %s: %m", bpffs_path); |
dedca960 JK |
93 | if (r == 0) |
94 | return log_unit_error_errno(u, SYNTHETIC_ERRNO(EINVAL), | |
b1acbc08 | 95 | "bpf-foreign: Path in BPF filesystem is expected."); |
dedca960 | 96 | |
5f8ba20d JK |
97 | r = bpf_program_new_from_bpffs_path(bpffs_path, &prog); |
98 | if (r < 0) | |
b1acbc08 | 99 | return log_unit_error_errno(u, r, "bpf-foreign: Failed to create foreign BPF program: %m"); |
5f8ba20d JK |
100 | |
101 | r = bpf_program_get_id_by_fd(prog->kernel_fd, &prog_id); | |
102 | if (r < 0) | |
b1acbc08 | 103 | return log_unit_error_errno(u, r, "bpf-foreign: Failed to get BPF program id from fd: %m"); |
5f8ba20d JK |
104 | |
105 | r = bpf_foreign_key_new(prog_id, attach_type, &key); | |
106 | if (r < 0) | |
107 | return log_unit_error_errno(u, r, | |
b1acbc08 | 108 | "bpf-foreign: Failed to create foreign BPF program key from path '%s': %m", bpffs_path); |
5f8ba20d JK |
109 | |
110 | r = hashmap_ensure_put(&u->bpf_foreign_by_key, &bpf_foreign_by_key_hash_ops, key, prog); | |
111 | if (r == -EEXIST) { | |
b1acbc08 | 112 | log_unit_warning_errno(u, r, "bpf-foreign: Foreign BPF program already exists, ignoring: %m"); |
5f8ba20d JK |
113 | return 0; |
114 | } | |
115 | if (r < 0) | |
b1acbc08 | 116 | return log_unit_error_errno(u, r, "bpf-foreign: Failed to put foreign BPF program into map: %m"); |
5f8ba20d JK |
117 | |
118 | TAKE_PTR(key); | |
119 | TAKE_PTR(prog); | |
120 | ||
121 | return 0; | |
122 | } | |
123 | ||
5f8ba20d JK |
124 | int bpf_foreign_install(Unit *u) { |
125 | _cleanup_free_ char *cgroup_path = NULL; | |
5f8ba20d JK |
126 | CGroupContext *cc; |
127 | int r; | |
128 | ||
129 | assert(u); | |
130 | ||
131 | cc = unit_get_cgroup_context(u); | |
132 | if (!cc) | |
133 | return 0; | |
134 | ||
135 | r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path, NULL, &cgroup_path); | |
136 | if (r < 0) | |
b1acbc08 | 137 | return log_unit_error_errno(u, r, "bpf-foreign: Failed to get cgroup path: %m"); |
5f8ba20d JK |
138 | |
139 | LIST_FOREACH(programs, p, cc->bpf_foreign_programs) { | |
140 | r = bpf_foreign_prepare(u, p->attach_type, p->bpffs_path); | |
141 | if (r < 0) | |
b1acbc08 | 142 | return log_unit_error_errno(u, r, "bpf-foreign: Failed to prepare foreign BPF hashmap: %m"); |
5f8ba20d JK |
143 | } |
144 | ||
145 | r = attach_programs(u, cgroup_path, u->bpf_foreign_by_key, BPF_F_ALLOW_MULTI); | |
146 | if (r < 0) | |
b1acbc08 | 147 | return log_unit_error_errno(u, r, "bpf-foreign: Failed to install foreign BPF programs: %m"); |
5f8ba20d JK |
148 | |
149 | return 0; | |
150 | } |