Skip to content
Navigation Menu
Toggle navigation
Sign in
In this repository
All GitHub Enterprise
↵
Jump to
↵
No suggested jump to results
In this repository
All GitHub Enterprise
↵
Jump to
↵
In this organization
All GitHub Enterprise
↵
Jump to
↵
In this repository
All GitHub Enterprise
↵
Jump to
↵
Sign in
Reseting focus
You signed in with another tab or window.
Reload
to refresh your session.
You signed out in another tab or window.
Reload
to refresh your session.
You switched accounts on another tab or window.
Reload
to refresh your session.
Dismiss alert
{{ message }}
mariux64
/
linux
Public
Notifications
You must be signed in to change notification settings
Fork
0
Star
0
Code
Issues
2
Pull requests
0
Actions
Projects
0
Wiki
Security
Insights
Additional navigation options
Code
Issues
Pull requests
Actions
Projects
Wiki
Security
Insights
Files
f4d0525
Documentation
LICENSES
arch
block
certs
crypto
drivers
fs
include
init
ipc
kernel
bpf
preload
Makefile
arraymap.c
bpf_inode_storage.c
bpf_iter.c
bpf_local_storage.c
bpf_lru_list.c
bpf_lru_list.h
bpf_lsm.c
bpf_struct_ops.c
bpf_struct_ops_types.h
btf.c
cgroup.c
core.c
cpumap.c
devmap.c
disasm.c
disasm.h
dispatcher.c
hashtab.c
helpers.c
inode.c
local_storage.c
lpm_trie.c
map_in_map.c
map_in_map.h
map_iter.c
net_namespace.c
offload.c
percpu_freelist.c
percpu_freelist.h
prog_iter.c
queue_stack_maps.c
reuseport_array.c
ringbuf.c
stackmap.c
syscall.c
sysfs_btf.c
task_iter.c
tnum.c
trampoline.c
verifier.c
cgroup
configs
debug
dma
entry
events
gcov
irq
kcsan
livepatch
locking
power
printk
rcu
sched
time
trace
.gitignore
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
Makefile
acct.c
async.c
audit.c
audit.h
audit_fsnotify.c
audit_tree.c
audit_watch.c
auditfilter.c
auditsc.c
backtracetest.c
bounds.c
capability.c
compat.c
configs.c
context_tracking.c
cpu.c
cpu_pm.c
crash_core.c
crash_dump.c
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c
extable.c
fail_function.c
fork.c
freezer.c
futex.c
gen_kheaders.sh
groups.c
hung_task.c
iomem.c
irq_work.c
jump_label.c
kallsyms.c
kcmp.c
kcov.c
kexec.c
kexec_core.c
kexec_elf.c
kexec_file.c
kexec_internal.h
kheaders.c
kmod.c
kprobes.c
ksysfs.c
kthread.c
latencytop.c
module-internal.h
module.c
module_signature.c
module_signing.c
notifier.c
nsproxy.c
padata.c
panic.c
params.c
pid.c
pid_namespace.c
profile.c
ptrace.c
range.c
reboot.c
regset.c
relay.c
resource.c
rseq.c
scs.c
seccomp.c
signal.c
smp.c
smpboot.c
smpboot.h
softirq.c
stackleak.c
stacktrace.c
stop_machine.c
sys.c
sys_ni.c
sysctl-test.c
sysctl.c
task_work.c
taskstats.c
test_kprobes.c
torture.c
tracepoint.c
tsacct.c
ucount.c
uid16.c
uid16.h
umh.c
up.c
user-return-notifier.c
user.c
user_namespace.c
usermode_driver.c
utsname.c
utsname_sysctl.c
watch_queue.c
watchdog.c
watchdog_hld.c
workqueue.c
workqueue_internal.h
lib
mm
net
samples
scripts
security
sound
tools
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile
README
Breadcrumbs
linux
/
kernel
/
bpf
/
reuseport_array.c
Blame
Blame
Latest commit
History
History
363 lines (304 loc) · 8.77 KB
Breadcrumbs
linux
/
kernel
/
bpf
/
reuseport_array.c
Top
File metadata and controls
Code
Blame
363 lines (304 loc) · 8.77 KB
Raw
// SPDX-License-Identifier: GPL-2.0 /* * Copyright (c) 2018 Facebook */ #include <linux/bpf.h> #include <linux/err.h> #include <linux/sock_diag.h> #include <net/sock_reuseport.h> struct reuseport_array { struct bpf_map map; struct sock __rcu *ptrs[]; }; static struct reuseport_array *reuseport_array(struct bpf_map *map) { return (struct reuseport_array *)map; } /* The caller must hold the reuseport_lock */ void bpf_sk_reuseport_detach(struct sock *sk) { uintptr_t sk_user_data; write_lock_bh(&sk->sk_callback_lock); sk_user_data = (uintptr_t)sk->sk_user_data; if (sk_user_data & SK_USER_DATA_BPF) { struct sock __rcu **socks; socks = (void *)(sk_user_data & SK_USER_DATA_PTRMASK); WRITE_ONCE(sk->sk_user_data, NULL); /* * Do not move this NULL assignment outside of * sk->sk_callback_lock because there is * a race with reuseport_array_free() * which does not hold the reuseport_lock. */ RCU_INIT_POINTER(*socks, NULL); } write_unlock_bh(&sk->sk_callback_lock); } static int reuseport_array_alloc_check(union bpf_attr *attr) { if (attr->value_size != sizeof(u32) && attr->value_size != sizeof(u64)) return -EINVAL; return array_map_alloc_check(attr); } static void *reuseport_array_lookup_elem(struct bpf_map *map, void *key) { struct reuseport_array *array = reuseport_array(map); u32 index = *(u32 *)key; if (unlikely(index >= array->map.max_entries)) return NULL; return rcu_dereference(array->ptrs[index]); } /* Called from syscall only */ static int reuseport_array_delete_elem(struct bpf_map *map, void *key) { struct reuseport_array *array = reuseport_array(map); u32 index = *(u32 *)key; struct sock *sk; int err; if (index >= map->max_entries) return -E2BIG; if (!rcu_access_pointer(array->ptrs[index])) return -ENOENT; spin_lock_bh(&reuseport_lock); sk = rcu_dereference_protected(array->ptrs[index], lockdep_is_held(&reuseport_lock)); if (sk) { write_lock_bh(&sk->sk_callback_lock); WRITE_ONCE(sk->sk_user_data, NULL); RCU_INIT_POINTER(array->ptrs[index], NULL); write_unlock_bh(&sk->sk_callback_lock); err = 0; } else { err = -ENOENT; } spin_unlock_bh(&reuseport_lock); return err; } static void reuseport_array_free(struct bpf_map *map) { struct reuseport_array *array = reuseport_array(map); struct sock *sk; u32 i; /* * ops->map_*_elem() will not be able to access this * array now. Hence, this function only races with * bpf_sk_reuseport_detach() which was triggerred by * close() or disconnect(). * * This function and bpf_sk_reuseport_detach() are * both removing sk from "array". Who removes it * first does not matter. * * The only concern here is bpf_sk_reuseport_detach() * may access "array" which is being freed here. * bpf_sk_reuseport_detach() access this "array" * through sk->sk_user_data _and_ with sk->sk_callback_lock * held which is enough because this "array" is not freed * until all sk->sk_user_data has stopped referencing this "array". * * Hence, due to the above, taking "reuseport_lock" is not * needed here. */ /* * Since reuseport_lock is not taken, sk is accessed under * rcu_read_lock() */ rcu_read_lock(); for (i = 0; i < map->max_entries; i++) { sk = rcu_dereference(array->ptrs[i]); if (sk) { write_lock_bh(&sk->sk_callback_lock); /* * No need for WRITE_ONCE(). At this point, * no one is reading it without taking the * sk->sk_callback_lock. */ sk->sk_user_data = NULL; write_unlock_bh(&sk->sk_callback_lock); RCU_INIT_POINTER(array->ptrs[i], NULL); } } rcu_read_unlock(); /* * Once reaching here, all sk->sk_user_data is not * referenceing this "array". "array" can be freed now. */ bpf_map_area_free(array); } static struct bpf_map *reuseport_array_alloc(union bpf_attr *attr) { int err, numa_node = bpf_map_attr_numa_node(attr); struct reuseport_array *array; struct bpf_map_memory mem; u64 array_size; if (!bpf_capable()) return ERR_PTR(-EPERM); array_size = sizeof(*array); array_size += (u64)attr->max_entries * sizeof(struct sock *); err = bpf_map_charge_init(&mem, array_size); if (err) return ERR_PTR(err); /* allocate all map elements and zero-initialize them */ array = bpf_map_area_alloc(array_size, numa_node); if (!array) { bpf_map_charge_finish(&mem); return ERR_PTR(-ENOMEM); } /* copy mandatory map attributes */ bpf_map_init_from_attr(&array->map, attr); bpf_map_charge_move(&array->map.memory, &mem); return &array->map; } int bpf_fd_reuseport_array_lookup_elem(struct bpf_map *map, void *key, void *value) { struct sock *sk; int err; if (map->value_size != sizeof(u64)) return -ENOSPC; rcu_read_lock(); sk = reuseport_array_lookup_elem(map, key); if (sk) { *(u64 *)value = sock_gen_cookie(sk); err = 0; } else { err = -ENOENT; } rcu_read_unlock(); return err; } static int reuseport_array_update_check(const struct reuseport_array *array, const struct sock *nsk, const struct sock *osk, const struct sock_reuseport *nsk_reuse, u32 map_flags) { if (osk && map_flags == BPF_NOEXIST) return -EEXIST; if (!osk && map_flags == BPF_EXIST) return -ENOENT; if (nsk->sk_protocol != IPPROTO_UDP && nsk->sk_protocol != IPPROTO_TCP) return -ENOTSUPP; if (nsk->sk_family != AF_INET && nsk->sk_family != AF_INET6) return -ENOTSUPP; if (nsk->sk_type != SOCK_STREAM && nsk->sk_type != SOCK_DGRAM) return -ENOTSUPP; /* * sk must be hashed (i.e. listening in the TCP case or binded * in the UDP case) and * it must also be a SO_REUSEPORT sk (i.e. reuse cannot be NULL). * * Also, sk will be used in bpf helper that is protected by * rcu_read_lock(). */ if (!sock_flag(nsk, SOCK_RCU_FREE) || !sk_hashed(nsk) || !nsk_reuse) return -EINVAL; /* READ_ONCE because the sk->sk_callback_lock may not be held here */ if (READ_ONCE(nsk->sk_user_data)) return -EBUSY; return 0; } /* * Called from syscall only. * The "nsk" in the fd refcnt. * The "osk" and "reuse" are protected by reuseport_lock. */ int bpf_fd_reuseport_array_update_elem(struct bpf_map *map, void *key, void *value, u64 map_flags) { struct reuseport_array *array = reuseport_array(map); struct sock *free_osk = NULL, *osk, *nsk; struct sock_reuseport *reuse; u32 index = *(u32 *)key; uintptr_t sk_user_data; struct socket *socket; int err, fd; if (map_flags > BPF_EXIST) return -EINVAL; if (index >= map->max_entries) return -E2BIG; if (map->value_size == sizeof(u64)) { u64 fd64 = *(u64 *)value; if (fd64 > S32_MAX) return -EINVAL; fd = fd64; } else { fd = *(int *)value; } socket = sockfd_lookup(fd, &err); if (!socket) return err; nsk = socket->sk; if (!nsk) { err = -EINVAL; goto put_file; } /* Quick checks before taking reuseport_lock */ err = reuseport_array_update_check(array, nsk, rcu_access_pointer(array->ptrs[index]), rcu_access_pointer(nsk->sk_reuseport_cb), map_flags); if (err) goto put_file; spin_lock_bh(&reuseport_lock); /* * Some of the checks only need reuseport_lock * but it is done under sk_callback_lock also * for simplicity reason. */ write_lock_bh(&nsk->sk_callback_lock); osk = rcu_dereference_protected(array->ptrs[index], lockdep_is_held(&reuseport_lock)); reuse = rcu_dereference_protected(nsk->sk_reuseport_cb, lockdep_is_held(&reuseport_lock)); err = reuseport_array_update_check(array, nsk, osk, reuse, map_flags); if (err) goto put_file_unlock; sk_user_data = (uintptr_t)&array->ptrs[index] | SK_USER_DATA_NOCOPY | SK_USER_DATA_BPF; WRITE_ONCE(nsk->sk_user_data, (void *)sk_user_data); rcu_assign_pointer(array->ptrs[index], nsk); free_osk = osk; err = 0; put_file_unlock: write_unlock_bh(&nsk->sk_callback_lock); if (free_osk) { write_lock_bh(&free_osk->sk_callback_lock); WRITE_ONCE(free_osk->sk_user_data, NULL); write_unlock_bh(&free_osk->sk_callback_lock); } spin_unlock_bh(&reuseport_lock); put_file: fput(socket->file); return err; } /* Called from syscall */ static int reuseport_array_get_next_key(struct bpf_map *map, void *key, void *next_key) { struct reuseport_array *array = reuseport_array(map); u32 index = key ? *(u32 *)key : U32_MAX; u32 *next = (u32 *)next_key; if (index >= array->map.max_entries) { *next = 0; return 0; } if (index == array->map.max_entries - 1) return -ENOENT; *next = index + 1; return 0; } static int reuseport_array_map_btf_id; const struct bpf_map_ops reuseport_array_ops = { .map_meta_equal = bpf_map_meta_equal, .map_alloc_check = reuseport_array_alloc_check, .map_alloc = reuseport_array_alloc, .map_free = reuseport_array_free, .map_lookup_elem = reuseport_array_lookup_elem, .map_get_next_key = reuseport_array_get_next_key, .map_delete_elem = reuseport_array_delete_elem, .map_btf_name = "reuseport_array", .map_btf_id = &reuseport_array_map_btf_id, };
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
You can’t perform that action at this time.