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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) | |
d512831a | 27 | return -ENOMEM; |
5f8ba20d JK |
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; | |
f81450f2 | 59 | int r, ret = 0; |
5f8ba20d JK |
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); | |
f81450f2 LP |
65 | if (r < 0) { |
66 | log_unit_error_errno(u, r, "bpf-foreign: Attaching foreign BPF program to cgroup %s failed: %m", path); | |
67 | if (ret >= 0) | |
68 | ret = r; | |
69 | } | |
5f8ba20d JK |
70 | } |
71 | ||
f81450f2 | 72 | return ret; |
5f8ba20d JK |
73 | } |
74 | ||
75 | /* | |
76 | * Prepare foreign BPF program for installation: | |
77 | * - Load the program from BPF filesystem to the kernel; | |
78 | * - Store program FD identified by program ID and attach type in the unit. | |
79 | */ | |
80 | static int bpf_foreign_prepare( | |
81 | Unit *u, | |
82 | enum bpf_attach_type attach_type, | |
83 | const char *bpffs_path) { | |
76dc1725 | 84 | _cleanup_(bpf_program_freep) BPFProgram *prog = NULL; |
5f8ba20d JK |
85 | _cleanup_free_ BPFForeignKey *key = NULL; |
86 | uint32_t prog_id; | |
87 | int r; | |
88 | ||
89 | assert(u); | |
90 | assert(bpffs_path); | |
91 | ||
dedca960 JK |
92 | r = path_is_fs_type(bpffs_path, BPF_FS_MAGIC); |
93 | if (r < 0) | |
94 | return log_unit_error_errno(u, r, | |
b1acbc08 | 95 | "bpf-foreign: Failed to determine filesystem type of %s: %m", bpffs_path); |
dedca960 JK |
96 | if (r == 0) |
97 | return log_unit_error_errno(u, SYNTHETIC_ERRNO(EINVAL), | |
b1acbc08 | 98 | "bpf-foreign: Path in BPF filesystem is expected."); |
dedca960 | 99 | |
5f8ba20d JK |
100 | r = bpf_program_new_from_bpffs_path(bpffs_path, &prog); |
101 | if (r < 0) | |
b1acbc08 | 102 | return log_unit_error_errno(u, r, "bpf-foreign: Failed to create foreign BPF program: %m"); |
5f8ba20d JK |
103 | |
104 | r = bpf_program_get_id_by_fd(prog->kernel_fd, &prog_id); | |
105 | if (r < 0) | |
b1acbc08 | 106 | return log_unit_error_errno(u, r, "bpf-foreign: Failed to get BPF program id from fd: %m"); |
5f8ba20d JK |
107 | |
108 | r = bpf_foreign_key_new(prog_id, attach_type, &key); | |
109 | if (r < 0) | |
110 | return log_unit_error_errno(u, r, | |
b1acbc08 | 111 | "bpf-foreign: Failed to create foreign BPF program key from path '%s': %m", bpffs_path); |
5f8ba20d JK |
112 | |
113 | r = hashmap_ensure_put(&u->bpf_foreign_by_key, &bpf_foreign_by_key_hash_ops, key, prog); | |
114 | if (r == -EEXIST) { | |
b1acbc08 | 115 | log_unit_warning_errno(u, r, "bpf-foreign: Foreign BPF program already exists, ignoring: %m"); |
5f8ba20d JK |
116 | return 0; |
117 | } | |
118 | if (r < 0) | |
b1acbc08 | 119 | return log_unit_error_errno(u, r, "bpf-foreign: Failed to put foreign BPF program into map: %m"); |
5f8ba20d JK |
120 | |
121 | TAKE_PTR(key); | |
122 | TAKE_PTR(prog); | |
123 | ||
124 | return 0; | |
125 | } | |
126 | ||
5f8ba20d JK |
127 | int bpf_foreign_install(Unit *u) { |
128 | _cleanup_free_ char *cgroup_path = NULL; | |
5f8ba20d | 129 | CGroupContext *cc; |
f81450f2 | 130 | int r, ret = 0; |
5f8ba20d JK |
131 | |
132 | assert(u); | |
133 | ||
134 | cc = unit_get_cgroup_context(u); | |
135 | if (!cc) | |
136 | return 0; | |
137 | ||
138 | r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path, NULL, &cgroup_path); | |
139 | if (r < 0) | |
b1acbc08 | 140 | return log_unit_error_errno(u, r, "bpf-foreign: Failed to get cgroup path: %m"); |
5f8ba20d JK |
141 | |
142 | LIST_FOREACH(programs, p, cc->bpf_foreign_programs) { | |
143 | r = bpf_foreign_prepare(u, p->attach_type, p->bpffs_path); | |
f81450f2 LP |
144 | if (r < 0 && ret >= 0) |
145 | ret = r; | |
5f8ba20d JK |
146 | } |
147 | ||
148 | r = attach_programs(u, cgroup_path, u->bpf_foreign_by_key, BPF_F_ALLOW_MULTI); | |
f81450f2 | 149 | return ret < 0 ? ret : r; |
5f8ba20d | 150 | } |