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authorMartin KaFai Lau <[email protected]>2023-05-19 17:45:47 -0700
committerMartin KaFai Lau <[email protected]>2023-05-19 22:44:28 -0700
commit18f558876ff0361e8ceb537cdf6fec8936ff6f72 (patch)
tree3ad42c66005ca05fd9774e0fb61e572754d4ca43
parent9343184cb31fef673566ff37c41a9f418deb9de3 (diff)
parent1a8bc2299f4028e9bac36020ffaaec27a0dfb9c1 (diff)
Merge branch 'bpf: Add socket destroy capability'
Aditi Ghag says: ==================== This patch set adds the capability to destroy sockets in BPF. We plan to use the capability in Cilium to force client sockets to reconnect when their remote load-balancing backends are deleted. The other use case is on-the-fly policy enforcement where existing socket connections prevented by policies need to be terminated. The use cases, and more details around the selected approach were presented at LPC 2022 - https://lpc.events/event/16/contributions/1358/. RFC discussion - https://lore.kernel.org/netdev/CABG=zsBEh-P4NXk23eBJw7eajB5YJeRS7oPXnTAzs=yob4EMoQ@mail.gmail.com/T/#u. v8 patch series - https://lore.kernel.org/bpf/[email protected]/ v9 highlights: Address review comments: Martin: - Rearranged the kfunc filter patch, and added the missing break statement. - Squashed the extended selftest/bpf patch. Yonghong: - Revised commit message for patch 1. (Below notes are same as v8 patch series that are still relevant. Refer to earlier patch series versions for other notes.) - I hit a snag while writing the kfunc where verifier complained about the `sock_common` type passed from TCP iterator. With kfuncs, there don't seem to be any options available to pass BTF type hints to the verifier (equivalent of `ARG_PTR_TO_BTF_ID_SOCK_COMMON`, as was the case with the helper). As a result, I changed the argument type of the sock_destory kfunc to `sock_common`. ==================== Signed-off-by: Martin KaFai Lau <[email protected]>
-rw-r--r--include/linux/btf.h18
-rw-r--r--include/net/udp.h1
-rw-r--r--kernel/bpf/btf.c65
-rw-r--r--kernel/bpf/verifier.c7
-rw-r--r--net/core/filter.c63
-rw-r--r--net/ipv4/tcp.c9
-rw-r--r--net/ipv4/tcp_ipv4.c7
-rw-r--r--net/ipv4/udp.c291
-rw-r--r--tools/testing/selftests/bpf/network_helpers.c23
-rw-r--r--tools/testing/selftests/bpf/network_helpers.h1
-rw-r--r--tools/testing/selftests/bpf/prog_tests/sock_destroy.c221
-rw-r--r--tools/testing/selftests/bpf/progs/sock_destroy_prog.c145
-rw-r--r--tools/testing/selftests/bpf/progs/sock_destroy_prog_fail.c22
13 files changed, 794 insertions, 79 deletions
diff --git a/include/linux/btf.h b/include/linux/btf.h
index 508199e38415..cac9f304e27a 100644
--- a/include/linux/btf.h
+++ b/include/linux/btf.h
@@ -98,10 +98,14 @@ struct btf_type;
union bpf_attr;
struct btf_show;
struct btf_id_set;
+struct bpf_prog;
+
+typedef int (*btf_kfunc_filter_t)(const struct bpf_prog *prog, u32 kfunc_id);
struct btf_kfunc_id_set {
struct module *owner;
struct btf_id_set8 *set;
+ btf_kfunc_filter_t filter;
};
struct btf_id_dtor_kfunc {
@@ -479,7 +483,6 @@ static inline void *btf_id_set8_contains(const struct btf_id_set8 *set, u32 id)
return bsearch(&id, set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func);
}
-struct bpf_prog;
struct bpf_verifier_log;
#ifdef CONFIG_BPF_SYSCALL
@@ -487,10 +490,10 @@ const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id);
const char *btf_name_by_offset(const struct btf *btf, u32 offset);
struct btf *btf_parse_vmlinux(void);
struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog);
-u32 *btf_kfunc_id_set_contains(const struct btf *btf,
- enum bpf_prog_type prog_type,
- u32 kfunc_btf_id);
-u32 *btf_kfunc_is_modify_return(const struct btf *btf, u32 kfunc_btf_id);
+u32 *btf_kfunc_id_set_contains(const struct btf *btf, u32 kfunc_btf_id,
+ const struct bpf_prog *prog);
+u32 *btf_kfunc_is_modify_return(const struct btf *btf, u32 kfunc_btf_id,
+ const struct bpf_prog *prog);
int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
const struct btf_kfunc_id_set *s);
int register_btf_fmodret_id_set(const struct btf_kfunc_id_set *kset);
@@ -517,8 +520,9 @@ static inline const char *btf_name_by_offset(const struct btf *btf,
return NULL;
}
static inline u32 *btf_kfunc_id_set_contains(const struct btf *btf,
- enum bpf_prog_type prog_type,
- u32 kfunc_btf_id)
+ u32 kfunc_btf_id,
+ struct bpf_prog *prog)
+
{
return NULL;
}
diff --git a/include/net/udp.h b/include/net/udp.h
index de4b528522bb..5cad44318d71 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -437,7 +437,6 @@ struct udp_seq_afinfo {
struct udp_iter_state {
struct seq_net_private p;
int bucket;
- struct udp_seq_afinfo *bpf_seq_afinfo;
};
void *udp_seq_start(struct seq_file *seq, loff_t *pos);
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 6b682b8e4b50..947f0b83bfad 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -222,10 +222,17 @@ enum btf_kfunc_hook {
enum {
BTF_KFUNC_SET_MAX_CNT = 256,
BTF_DTOR_KFUNC_MAX_CNT = 256,
+ BTF_KFUNC_FILTER_MAX_CNT = 16,
+};
+
+struct btf_kfunc_hook_filter {
+ btf_kfunc_filter_t filters[BTF_KFUNC_FILTER_MAX_CNT];
+ u32 nr_filters;
};
struct btf_kfunc_set_tab {
struct btf_id_set8 *sets[BTF_KFUNC_HOOK_MAX];
+ struct btf_kfunc_hook_filter hook_filters[BTF_KFUNC_HOOK_MAX];
};
struct btf_id_dtor_kfunc_tab {
@@ -7669,9 +7676,12 @@ static int btf_check_kfunc_protos(struct btf *btf, u32 func_id, u32 func_flags)
/* Kernel Function (kfunc) BTF ID set registration API */
static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook,
- struct btf_id_set8 *add_set)
+ const struct btf_kfunc_id_set *kset)
{
+ struct btf_kfunc_hook_filter *hook_filter;
+ struct btf_id_set8 *add_set = kset->set;
bool vmlinux_set = !btf_is_module(btf);
+ bool add_filter = !!kset->filter;
struct btf_kfunc_set_tab *tab;
struct btf_id_set8 *set;
u32 set_cnt;
@@ -7686,6 +7696,24 @@ static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook,
return 0;
tab = btf->kfunc_set_tab;
+
+ if (tab && add_filter) {
+ u32 i;
+
+ hook_filter = &tab->hook_filters[hook];
+ for (i = 0; i < hook_filter->nr_filters; i++) {
+ if (hook_filter->filters[i] == kset->filter) {
+ add_filter = false;
+ break;
+ }
+ }
+
+ if (add_filter && hook_filter->nr_filters == BTF_KFUNC_FILTER_MAX_CNT) {
+ ret = -E2BIG;
+ goto end;
+ }
+ }
+
if (!tab) {
tab = kzalloc(sizeof(*tab), GFP_KERNEL | __GFP_NOWARN);
if (!tab)
@@ -7708,7 +7736,7 @@ static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook,
*/
if (!vmlinux_set) {
tab->sets[hook] = add_set;
- return 0;
+ goto do_add_filter;
}
/* In case of vmlinux sets, there may be more than one set being
@@ -7750,6 +7778,11 @@ static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook,
sort(set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func, NULL);
+do_add_filter:
+ if (add_filter) {
+ hook_filter = &tab->hook_filters[hook];
+ hook_filter->filters[hook_filter->nr_filters++] = kset->filter;
+ }
return 0;
end:
btf_free_kfunc_set_tab(btf);
@@ -7758,15 +7791,22 @@ end:
static u32 *__btf_kfunc_id_set_contains(const struct btf *btf,
enum btf_kfunc_hook hook,
- u32 kfunc_btf_id)
+ u32 kfunc_btf_id,
+ const struct bpf_prog *prog)
{
+ struct btf_kfunc_hook_filter *hook_filter;
struct btf_id_set8 *set;
- u32 *id;
+ u32 *id, i;
if (hook >= BTF_KFUNC_HOOK_MAX)
return NULL;
if (!btf->kfunc_set_tab)
return NULL;
+ hook_filter = &btf->kfunc_set_tab->hook_filters[hook];
+ for (i = 0; i < hook_filter->nr_filters; i++) {
+ if (hook_filter->filters[i](prog, kfunc_btf_id))
+ return NULL;
+ }
set = btf->kfunc_set_tab->sets[hook];
if (!set)
return NULL;
@@ -7821,23 +7861,25 @@ static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type)
* protection for looking up a well-formed btf->kfunc_set_tab.
*/
u32 *btf_kfunc_id_set_contains(const struct btf *btf,
- enum bpf_prog_type prog_type,
- u32 kfunc_btf_id)
+ u32 kfunc_btf_id,
+ const struct bpf_prog *prog)
{
+ enum bpf_prog_type prog_type = resolve_prog_type(prog);
enum btf_kfunc_hook hook;
u32 *kfunc_flags;
- kfunc_flags = __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_COMMON, kfunc_btf_id);
+ kfunc_flags = __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_COMMON, kfunc_btf_id, prog);
if (kfunc_flags)
return kfunc_flags;
hook = bpf_prog_type_to_kfunc_hook(prog_type);
- return __btf_kfunc_id_set_contains(btf, hook, kfunc_btf_id);
+ return __btf_kfunc_id_set_contains(btf, hook, kfunc_btf_id, prog);
}
-u32 *btf_kfunc_is_modify_return(const struct btf *btf, u32 kfunc_btf_id)
+u32 *btf_kfunc_is_modify_return(const struct btf *btf, u32 kfunc_btf_id,
+ const struct bpf_prog *prog)
{
- return __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_FMODRET, kfunc_btf_id);
+ return __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_FMODRET, kfunc_btf_id, prog);
}
static int __register_btf_kfunc_id_set(enum btf_kfunc_hook hook,
@@ -7868,7 +7910,8 @@ static int __register_btf_kfunc_id_set(enum btf_kfunc_hook hook,
goto err_out;
}
- ret = btf_populate_kfunc_set(btf, hook, kset->set);
+ ret = btf_populate_kfunc_set(btf, hook, kset);
+
err_out:
btf_put(btf);
return ret;
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index f597491259ab..af70dad655ab 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -10939,7 +10939,7 @@ static int fetch_kfunc_meta(struct bpf_verifier_env *env,
*kfunc_name = func_name;
func_proto = btf_type_by_id(desc_btf, func->type);
- kfunc_flags = btf_kfunc_id_set_contains(desc_btf, resolve_prog_type(env->prog), func_id);
+ kfunc_flags = btf_kfunc_id_set_contains(desc_btf, func_id, env->prog);
if (!kfunc_flags) {
return -EACCES;
}
@@ -19010,7 +19010,8 @@ int bpf_check_attach_target(struct bpf_verifier_log *log,
* in the fmodret id set with the KF_SLEEPABLE flag.
*/
else {
- u32 *flags = btf_kfunc_is_modify_return(btf, btf_id);
+ u32 *flags = btf_kfunc_is_modify_return(btf, btf_id,
+ prog);
if (flags && (*flags & KF_SLEEPABLE))
ret = 0;
@@ -19038,7 +19039,7 @@ int bpf_check_attach_target(struct bpf_verifier_log *log,
return -EINVAL;
}
ret = -EINVAL;
- if (btf_kfunc_is_modify_return(btf, btf_id) ||
+ if (btf_kfunc_is_modify_return(btf, btf_id, prog) ||
!check_attach_modify_return(addr, tname))
ret = 0;
if (ret) {
diff --git a/net/core/filter.c b/net/core/filter.c
index 451b0ec7f242..968139f4a1ac 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -11723,3 +11723,66 @@ static int __init bpf_kfunc_init(void)
return ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_XDP, &bpf_kfunc_set_xdp);
}
late_initcall(bpf_kfunc_init);
+
+/* Disables missing prototype warnings */
+__diag_push();
+__diag_ignore_all("-Wmissing-prototypes",
+ "Global functions as their definitions will be in vmlinux BTF");
+
+/* bpf_sock_destroy: Destroy the given socket with ECONNABORTED error code.
+ *
+ * The function expects a non-NULL pointer to a socket, and invokes the
+ * protocol specific socket destroy handlers.
+ *
+ * The helper can only be called from BPF contexts that have acquired the socket
+ * locks.
+ *
+ * Parameters:
+ * @sock: Pointer to socket to be destroyed
+ *
+ * Return:
+ * On error, may return EPROTONOSUPPORT, EINVAL.
+ * EPROTONOSUPPORT if protocol specific destroy handler is not supported.
+ * 0 otherwise
+ */
+__bpf_kfunc int bpf_sock_destroy(struct sock_common *sock)
+{
+ struct sock *sk = (struct sock *)sock;
+
+ /* The locking semantics that allow for synchronous execution of the
+ * destroy handlers are only supported for TCP and UDP.
+ * Supporting protocols will need to acquire sock lock in the BPF context
+ * prior to invoking this kfunc.
+ */
+ if (!sk->sk_prot->diag_destroy || (sk->sk_protocol != IPPROTO_TCP &&
+ sk->sk_protocol != IPPROTO_UDP))
+ return -EOPNOTSUPP;
+
+ return sk->sk_prot->diag_destroy(sk, ECONNABORTED);
+}
+
+__diag_pop()
+
+BTF_SET8_START(bpf_sk_iter_kfunc_ids)
+BTF_ID_FLAGS(func, bpf_sock_destroy, KF_TRUSTED_ARGS)
+BTF_SET8_END(bpf_sk_iter_kfunc_ids)
+
+static int tracing_iter_filter(const struct bpf_prog *prog, u32 kfunc_id)
+{
+ if (btf_id_set8_contains(&bpf_sk_iter_kfunc_ids, kfunc_id) &&
+ prog->expected_attach_type != BPF_TRACE_ITER)
+ return -EACCES;
+ return 0;
+}
+
+static const struct btf_kfunc_id_set bpf_sk_iter_kfunc_set = {
+ .owner = THIS_MODULE,
+ .set = &bpf_sk_iter_kfunc_ids,
+ .filter = tracing_iter_filter,
+};
+
+static int init_subsystem(void)
+{
+ return register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &bpf_sk_iter_kfunc_set);
+}
+late_initcall(init_subsystem);
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 4d6392c16b7a..87a04c3d9425 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -4682,8 +4682,10 @@ int tcp_abort(struct sock *sk, int err)
return 0;
}
- /* Don't race with userspace socket closes such as tcp_close. */
- lock_sock(sk);
+ /* BPF context ensures sock locking. */
+ if (!has_current_bpf_ctx())
+ /* Don't race with userspace socket closes such as tcp_close. */
+ lock_sock(sk);
if (sk->sk_state == TCP_LISTEN) {
tcp_set_state(sk, TCP_CLOSE);
@@ -4707,7 +4709,8 @@ int tcp_abort(struct sock *sk, int err)
bh_unlock_sock(sk);
local_bh_enable();
tcp_write_queue_purge(sk);
- release_sock(sk);
+ if (!has_current_bpf_ctx())
+ release_sock(sk);
return 0;
}
EXPORT_SYMBOL_GPL(tcp_abort);
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index db24ed8f8509..6c2a5f1c63c4 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2962,7 +2962,6 @@ static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v)
struct bpf_iter_meta meta;
struct bpf_prog *prog;
struct sock *sk = v;
- bool slow;
uid_t uid;
int ret;
@@ -2970,7 +2969,7 @@ static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v)
return 0;
if (sk_fullsock(sk))
- slow = lock_sock_fast(sk);
+ lock_sock(sk);
if (unlikely(sk_unhashed(sk))) {
ret = SEQ_SKIP;
@@ -2994,7 +2993,7 @@ static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v)
unlock:
if (sk_fullsock(sk))
- unlock_sock_fast(sk, slow);
+ release_sock(sk);
return ret;
}
@@ -3356,7 +3355,7 @@ static struct bpf_iter_reg tcp_reg_info = {
.ctx_arg_info_size = 1,
.ctx_arg_info = {
{ offsetof(struct bpf_iter__tcp, sk_common),
- PTR_TO_BTF_ID_OR_NULL },
+ PTR_TO_BTF_ID_OR_NULL | PTR_TRUSTED },
},
.get_func_proto = bpf_iter_tcp_get_func_proto,
.seq_info = &tcp_seq_info,
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index aa32afd871ee..6893fb867529 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2930,7 +2930,8 @@ EXPORT_SYMBOL(udp_poll);
int udp_abort(struct sock *sk, int err)
{
- lock_sock(sk);
+ if (!has_current_bpf_ctx())
+ lock_sock(sk);
/* udp{v6}_destroy_sock() sets it under the sk lock, avoid racing
* with close()
@@ -2943,7 +2944,8 @@ int udp_abort(struct sock *sk, int err)
__udp_disconnect(sk, 0);
out:
- release_sock(sk);
+ if (!has_current_bpf_ctx())
+ release_sock(sk);
return 0;
}
@@ -2988,9 +2990,30 @@ EXPORT_SYMBOL(udp_prot);
/* ------------------------------------------------------------------------ */
#ifdef CONFIG_PROC_FS
-static struct udp_table *udp_get_table_afinfo(struct udp_seq_afinfo *afinfo,
- struct net *net)
+static unsigned short seq_file_family(const struct seq_file *seq);
+static bool seq_sk_match(struct seq_file *seq, const struct sock *sk)
+{
+ unsigned short family = seq_file_family(seq);
+
+ /* AF_UNSPEC is used as a match all */
+ return ((family == AF_UNSPEC || family == sk->sk_family) &&
+ net_eq(sock_net(sk), seq_file_net(seq)));
+}
+
+#ifdef CONFIG_BPF_SYSCALL
+static const struct seq_operations bpf_iter_udp_seq_ops;
+#endif
+static struct udp_table *udp_get_table_seq(struct seq_file *seq,
+ struct net *net)
{
+ const struct udp_seq_afinfo *afinfo;
+
+#ifdef CONFIG_BPF_SYSCALL
+ if (seq->op == &bpf_iter_udp_seq_ops)
+ return net->ipv4.udp_table;
+#endif
+
+ afinfo = pde_data(file_inode(seq->file));
return afinfo->udp_table ? : net->ipv4.udp_table;
}
@@ -2998,16 +3021,10 @@ static struct sock *udp_get_first(struct seq_file *seq, int start)
{
struct udp_iter_state *state = seq->private;
struct net *net = seq_file_net(seq);
- struct udp_seq_afinfo *afinfo;
struct udp_table *udptable;
struct sock *sk;
- if (state->bpf_seq_afinfo)
- afinfo = state->bpf_seq_afinfo;
- else
- afinfo = pde_data(file_inode(seq->file));
-
- udptable = udp_get_table_afinfo(afinfo, net);
+ udptable = udp_get_table_seq(seq, net);
for (state->bucket = start; state->bucket <= udptable->mask;
++state->bucket) {
@@ -3018,10 +3035,7 @@ static struct sock *udp_get_first(struct seq_file *seq, int start)
spin_lock_bh(&hslot->lock);
sk_for_each(sk, &hslot->head) {
- if (!net_eq(sock_net(sk), net))
- continue;
- if (afinfo->family == AF_UNSPEC ||
- sk->sk_family == afinfo->family)
+ if (seq_sk_match(seq, sk))
goto found;
}
spin_unlock_bh(&hslot->lock);
@@ -3035,22 +3049,14 @@ static struct sock *udp_get_next(struct seq_file *seq, struct sock *sk)
{
struct udp_iter_state *state = seq->private;
struct net *net = seq_file_net(seq);
- struct udp_seq_afinfo *afinfo;
struct udp_table *udptable;
- if (state->bpf_seq_afinfo)
- afinfo = state->bpf_seq_afinfo;
- else
- afinfo = pde_data(file_inode(seq->file));
-
do {
sk = sk_next(sk);
- } while (sk && (!net_eq(sock_net(sk), net) ||
- (afinfo->family != AF_UNSPEC &&
- sk->sk_family != afinfo->family)));
+ } while (sk && !seq_sk_match(seq, sk));
if (!sk) {
- udptable = udp_get_table_afinfo(afinfo, net);
+ udptable = udp_get_table_seq(seq, net);
if (state->bucket <= udptable->mask)
spin_unlock_bh(&udptable->hash[state->bucket].lock);
@@ -3096,15 +3102,9 @@ EXPORT_SYMBOL(udp_seq_next);
void udp_seq_stop(struct seq_file *seq, void *v)
{
struct udp_iter_state *state = seq->private;
- struct udp_seq_afinfo *afinfo;
struct udp_table *udptable;
- if (state->bpf_seq_afinfo)
- afinfo = state->bpf_seq_afinfo;
- else
- afinfo = pde_data(file_inode(seq->file));
-
- udptable = udp_get_table_afinfo(afinfo, seq_file_net(seq));
+ udptable = udp_get_table_seq(seq, seq_file_net(seq));
if (state->bucket <= udptable->mask)
spin_unlock_bh(&udptable->hash[state->bucket].lock);
@@ -3157,6 +3157,143 @@ struct bpf_iter__udp {
int bucket __aligned(8);
};
+struct bpf_udp_iter_state {
+ struct udp_iter_state state;
+ unsigned int cur_sk;
+ unsigned int end_sk;
+ unsigned int max_sk;
+ int offset;
+ struct sock **batch;
+ bool st_bucket_done;
+};
+
+static int bpf_iter_udp_realloc_batch(struct bpf_udp_iter_state *iter,
+ unsigned int new_batch_sz);
+static struct sock *bpf_iter_udp_batch(struct seq_file *seq)
+{
+ struct bpf_udp_iter_state *iter = seq->private;
+ struct udp_iter_state *state = &iter->state;
+ struct net *net = seq_file_net(seq);
+ struct udp_table *udptable;
+ unsigned int batch_sks = 0;
+ bool resized = false;
+ struct sock *sk;
+
+ /* The current batch is done, so advance the bucket. */
+ if (iter->st_bucket_done) {
+ state->bucket++;
+ iter->offset = 0;
+ }
+
+ udptable = udp_get_table_seq(seq, net);
+
+again:
+ /* New batch for the next bucket.
+ * Iterate over the hash table to find a bucket with sockets matching
+ * the iterator attributes, and return the first matching socket from
+ * the bucket. The remaining matched sockets from the bucket are batched
+ * before releasing the bucket lock. This allows BPF programs that are
+ * called in seq_show to acquire the bucket lock if needed.
+ */
+ iter->cur_sk = 0;
+ iter->end_sk = 0;
+ iter->st_bucket_done = false;
+ batch_sks = 0;
+
+ for (; state->bucket <= udptable->mask; state->bucket++) {
+ struct udp_hslot *hslot2 = &udptable->hash2[state->bucket];
+
+ if (hlist_empty(&hslot2->head)) {
+ iter->offset = 0;
+ continue;
+ }
+
+ spin_lock_bh(&hslot2->lock);
+ udp_portaddr_for_each_entry(sk, &hslot2->head) {
+ if (seq_sk_match(seq, sk)) {
+ /* Resume from the last iterated socket at the
+ * offset in the bucket before iterator was stopped.
+ */
+ if (iter->offset) {
+ --iter->offset;
+ continue;
+ }
+ if (iter->end_sk < iter->max_sk) {
+ sock_hold(sk);
+ iter->batch[iter->end_sk++] = sk;
+ }
+ batch_sks++;
+ }
+ }
+ spin_unlock_bh(&hslot2->lock);
+
+ if (iter->end_sk)
+ break;
+
+ /* Reset the current bucket's offset before moving to the next bucket. */
+ iter->offset = 0;
+ }
+
+ /* All done: no batch made. */
+ if (!iter->end_sk)
+ return NULL;
+
+ if (iter->end_sk == batch_sks) {
+ /* Batching is done for the current bucket; return the first
+ * socket to be iterated from the batch.
+ */
+ iter->st_bucket_done = true;
+ goto done;
+ }
+ if (!resized && !bpf_iter_udp_realloc_batch(iter, batch_sks * 3 / 2)) {
+ resized = true;
+ /* After allocating a larger batch, retry one more time to grab
+ * the whole bucket.
+ */
+ state->bucket--;
+ goto again;
+ }
+done:
+ return iter->batch[0];
+}
+
+static void *bpf_iter_udp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+ struct bpf_udp_iter_state *iter = seq->private;
+ struct sock *sk;
+
+ /* Whenever seq_next() is called, the iter->cur_sk is
+ * done with seq_show(), so unref the iter->cur_sk.
+ */
+ if (iter->cur_sk < iter->end_sk) {
+ sock_put(iter->batch[iter->cur_sk++]);
+ ++iter->offset;
+ }
+
+ /* After updating iter->cur_sk, check if there are more sockets
+ * available in the current bucket batch.
+ */
+ if (iter->cur_sk < iter->end_sk)
+ sk = iter->batch[iter->cur_sk];
+ else
+ /* Prepare a new batch. */
+ sk = bpf_iter_udp_batch(seq);
+
+ ++*pos;
+ return sk;
+}
+
+static void *bpf_iter_udp_seq_start(struct seq_file *seq, loff_t *pos)
+{
+ /* bpf iter does not support lseek, so it always
+ * continue from where it was stop()-ped.
+ */
+ if (*pos)
+ return bpf_iter_udp_batch(seq);
+
+ return SEQ_START_TOKEN;
+}
+
static int udp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
struct udp_sock *udp_sk, uid_t uid, int bucket)
{
@@ -3177,18 +3314,37 @@ static int bpf_iter_udp_seq_show(struct seq_file *seq, void *v)
struct bpf_prog *prog;
struct sock *sk = v;
uid_t uid;
+ int ret;
if (v == SEQ_START_TOKEN)
return 0;
+ lock_sock(sk);
+
+ if (unlikely(sk_unhashed(sk))) {
+ ret = SEQ_SKIP;
+ goto unlock;
+ }
+
uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
meta.seq = seq;
prog = bpf_iter_get_info(&meta, false);
- return udp_prog_seq_show(prog, &meta, v, uid, state->bucket);
+ ret = udp_prog_seq_show(prog, &meta, v, uid, state->bucket);
+
+unlock:
+ release_sock(sk);
+ return ret;
+}
+
+static void bpf_iter_udp_put_batch(struct bpf_udp_iter_state *iter)
+{
+ while (iter->cur_sk < iter->end_sk)
+ sock_put(iter->batch[iter->cur_sk++]);
}
static void bpf_iter_udp_seq_stop(struct seq_file *seq, void *v)
{
+ struct bpf_udp_iter_state *iter = seq->private;
struct bpf_iter_meta meta;
struct bpf_prog *prog;
@@ -3199,17 +3355,35 @@ static void bpf_iter_udp_seq_stop(struct seq_file *seq, void *v)
(void)udp_prog_seq_show(prog, &meta, v, 0, 0);
}
- udp_seq_stop(seq, v);
+ if (iter->cur_sk < iter->end_sk) {
+ bpf_iter_udp_put_batch(iter);
+ iter->st_bucket_done = false;
+ }
}
static const struct seq_operations bpf_iter_udp_seq_ops = {
- .start = udp_seq_start,
- .next = udp_seq_next,
+ .start = bpf_iter_udp_seq_start,
+ .next = bpf_iter_udp_seq_next,
.stop = bpf_iter_udp_seq_stop,
.show = bpf_iter_udp_seq_show,
};
#endif
+static unsigned short seq_file_family(const struct seq_file *seq)
+{
+ const struct udp_seq_afinfo *afinfo;
+
+#ifdef CONFIG_BPF_SYSCALL
+ /* BPF iterator: bpf programs to filter sockets. */
+ if (seq->op == &bpf_iter_udp_seq_ops)
+ return AF_UNSPEC;
+#endif
+
+ /* Proc fs iterator */
+ afinfo = pde_data(file_inode(seq->file));
+ return afinfo->family;
+}
+
const struct seq_operations udp_seq_ops = {
.start = udp_seq_start,
.next = udp_seq_next,
@@ -3418,38 +3592,55 @@ static struct pernet_operations __net_initdata udp_sysctl_ops = {
DEFINE_BPF_ITER_FUNC(udp, struct bpf_iter_meta *meta,
struct udp_sock *udp_sk, uid_t uid, int bucket)
-static int bpf_iter_init_udp(void *priv_data, struct bpf_iter_aux_info *aux)
+static int bpf_iter_udp_realloc_batch(struct bpf_udp_iter_state *iter,
+ unsigned int new_batch_sz)
{
- struct udp_iter_state *st = priv_data;
- struct udp_seq_afinfo *afinfo;
- int ret;
+ struct sock **new_batch;
- afinfo = kmalloc(sizeof(*afinfo), GFP_USER | __GFP_NOWARN);
- if (!afinfo)
+ new_batch = kvmalloc_array(new_batch_sz, sizeof(*new_batch),
+ GFP_USER | __GFP_NOWARN);
+ if (!new_batch)
return -ENOMEM;
- afinfo->family = AF_UNSPEC;
- afinfo->udp_table = NULL;
- st->bpf_seq_afinfo = afinfo;
+ bpf_iter_udp_put_batch(iter);
+ kvfree(iter->batch);
+ iter->batch = new_batch;
+ iter->max_sk = new_batch_sz;
+
+ return 0;
+}
+
+#define INIT_BATCH_SZ 16
+
+static int bpf_iter_init_udp(void *priv_data, struct bpf_iter_aux_info *aux)
+{
+ struct bpf_udp_iter_state *iter = priv_data;
+ int ret;
+
ret = bpf_iter_init_seq_net(priv_data, aux);
if (ret)
- kfree(afinfo);
+ return ret;
+
+ ret = bpf_iter_udp_realloc_batch(iter, INIT_BATCH_SZ);
+ if (ret)
+ bpf_iter_fini_seq_net(priv_data);
+
return ret;
}
static void bpf_iter_fini_udp(void *priv_data)
{
- struct udp_iter_state *st = priv_data;
+ struct bpf_udp_iter_state *iter = priv_data;
- kfree(st->bpf_seq_afinfo);
bpf_iter_fini_seq_net(priv_data);
+ kvfree(iter->batch);
}
static const struct bpf_iter_seq_info udp_seq_info = {
.seq_ops = &bpf_iter_udp_seq_ops,
.init_seq_private = bpf_iter_init_udp,
.fini_seq_private = bpf_iter_fini_udp,
- .seq_priv_size = sizeof(struct udp_iter_state),
+ .seq_priv_size = sizeof(struct bpf_udp_iter_state),
};
static struct bpf_iter_reg udp_reg_info = {
@@ -3457,7 +3648,7 @@ static struct bpf_iter_reg udp_reg_info = {
.ctx_arg_info_size = 1,
.ctx_arg_info = {
{ offsetof(struct bpf_iter__udp, udp_sk),
- PTR_TO_BTF_ID_OR_NULL },
+ PTR_TO_BTF_ID_OR_NULL | PTR_TRUSTED },
},
.seq_info = &udp_seq_info,
};
diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c
index 596caa176582..a105c0cd008a 100644
--- a/tools/testing/selftests/bpf/network_helpers.c
+++ b/tools/testing/selftests/bpf/network_helpers.c
@@ -427,3 +427,26 @@ void close_netns(struct nstoken *token)
close(token->orig_netns_fd);
free(token);
}
+
+int get_socket_local_port(int sock_fd)
+{
+ struct sockaddr_storage addr;
+ socklen_t addrlen = sizeof(addr);
+ int err;
+
+ err = getsockname(sock_fd, (struct sockaddr *)&addr, &addrlen);
+ if (err < 0)
+ return err;
+
+ if (addr.ss_family == AF_INET) {
+ struct sockaddr_in *sin = (struct sockaddr_in *)&addr;
+
+ return sin->sin_port;
+ } else if (addr.ss_family == AF_INET6) {
+ struct sockaddr_in6 *sin = (struct sockaddr_in6 *)&addr;
+
+ return sin->sin6_port;
+ }
+
+ return -1;
+}
diff --git a/tools/testing/selftests/bpf/network_helpers.h b/tools/testing/selftests/bpf/network_helpers.h
index f882c691b790..694185644da6 100644
--- a/tools/testing/selftests/bpf/network_helpers.h
+++ b/tools/testing/selftests/bpf/network_helpers.h
@@ -56,6 +56,7 @@ int fastopen_connect(int server_fd, const char *data, unsigned int data_len,
int make_sockaddr(int family, const char *addr_str, __u16 port,
struct sockaddr_storage *addr, socklen_t *len);
char *ping_command(int family);
+int get_socket_local_port(int sock_fd);
struct nstoken;
/**
diff --git a/tools/testing/selftests/bpf/prog_tests/sock_destroy.c b/tools/testing/selftests/bpf/prog_tests/sock_destroy.c
new file mode 100644
index 000000000000..b0583309a94e
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/sock_destroy.c
@@ -0,0 +1,221 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+#include <bpf/bpf_endian.h>
+
+#include "sock_destroy_prog.skel.h"
+#include "sock_destroy_prog_fail.skel.h"
+#include "network_helpers.h"
+
+#define TEST_NS "sock_destroy_netns"
+
+static void start_iter_sockets(struct bpf_program *prog)
+{
+ struct bpf_link *link;
+ char buf[50] = {};
+ int iter_fd, len;
+
+ link = bpf_program__attach_iter(prog, NULL);
+ if (!ASSERT_OK_PTR(link, "attach_iter"))
+ return;
+
+ iter_fd = bpf_iter_create(bpf_link__fd(link));
+ if (!ASSERT_GE(iter_fd, 0, "create_iter"))
+ goto free_link;
+
+ while ((len = read(iter_fd, buf, sizeof(buf))) > 0)
+ ;
+ ASSERT_GE(len, 0, "read");
+
+ close(iter_fd);
+
+free_link:
+ bpf_link__destroy(link);
+}
+
+static void test_tcp_client(struct sock_destroy_prog *skel)
+{
+ int serv = -1, clien = -1, accept_serv = -1, n;
+
+ serv = start_server(AF_INET6, SOCK_STREAM, NULL, 0, 0);
+ if (!ASSERT_GE(serv, 0, "start_server"))
+ goto cleanup;
+
+ clien = connect_to_fd(serv, 0);
+ if (!ASSERT_GE(clien, 0, "connect_to_fd"))
+ goto cleanup;
+
+ accept_serv = accept(serv, NULL, NULL);
+ if (!ASSERT_GE(accept_serv, 0, "serv accept"))
+ goto cleanup;
+
+ n = send(clien, "t", 1, 0);
+ if (!ASSERT_EQ(n, 1, "client send"))
+ goto cleanup;
+
+ /* Run iterator program that destroys connected client sockets. */
+ start_iter_sockets(skel->progs.iter_tcp6_client);
+
+ n = send(clien, "t", 1, 0);
+ if (!ASSERT_LT(n, 0, "client_send on destroyed socket"))
+ goto cleanup;
+ ASSERT_EQ(errno, ECONNABORTED, "error code on destroyed socket");
+
+cleanup:
+ if (clien != -1)
+ close(clien);
+ if (accept_serv != -1)
+ close(accept_serv);
+ if (serv != -1)
+ close(serv);
+}
+
+static void test_tcp_server(struct sock_destroy_prog *skel)
+{
+ int serv = -1, clien = -1, accept_serv = -1, n, serv_port;
+
+ serv = start_server(AF_INET6, SOCK_STREAM, NULL, 0, 0);
+ if (!ASSERT_GE(serv, 0, "start_server"))
+ goto cleanup;
+ serv_port = get_socket_local_port(serv);
+ if (!ASSERT_GE(serv_port, 0, "get_sock_local_port"))
+ goto cleanup;
+ skel->bss->serv_port = (__be16) serv_port;
+
+ clien = connect_to_fd(serv, 0);
+ if (!ASSERT_GE(clien, 0, "connect_to_fd"))
+ goto cleanup;
+
+ accept_serv = accept(serv, NULL, NULL);
+ if (!ASSERT_GE(accept_serv, 0, "serv accept"))
+ goto cleanup;
+
+ n = send(clien, "t", 1, 0);
+ if (!ASSERT_EQ(n, 1, "client send"))
+ goto cleanup;
+
+ /* Run iterator program that destroys server sockets. */
+ start_iter_sockets(skel->progs.iter_tcp6_server);
+
+ n = send(clien, "t", 1, 0);
+ if (!ASSERT_LT(n, 0, "client_send on destroyed socket"))
+ goto cleanup;
+ ASSERT_EQ(errno, ECONNRESET, "error code on destroyed socket");
+
+cleanup:
+ if (clien != -1)
+ close(clien);
+ if (accept_serv != -1)
+ close(accept_serv);
+ if (serv != -1)
+ close(serv);
+}
+
+static void test_udp_client(struct sock_destroy_prog *skel)
+{
+ int serv = -1, clien = -1, n = 0;
+
+ serv = start_server(AF_INET6, SOCK_DGRAM, NULL, 0, 0);
+ if (!ASSERT_GE(serv, 0, "start_server"))
+ goto cleanup;
+
+ clien = connect_to_fd(serv, 0);
+ if (!ASSERT_GE(clien, 0, "connect_to_fd"))
+ goto cleanup;
+
+ n = send(clien, "t", 1, 0);
+ if (!ASSERT_EQ(n, 1, "client send"))
+ goto cleanup;
+
+ /* Run iterator program that destroys sockets. */
+ start_iter_sockets(skel->progs.iter_udp6_client);
+
+ n = send(clien, "t", 1, 0);
+ if (!ASSERT_LT(n, 0, "client_send on destroyed socket"))
+ goto cleanup;
+ /* UDP sockets have an overriding error code after they are disconnected,
+ * so we don't check for ECONNABORTED error code.
+ */
+
+cleanup:
+ if (clien != -1)
+ close(clien);
+ if (serv != -1)
+ close(serv);
+}
+
+static void test_udp_server(struct sock_destroy_prog *skel)
+{
+ int *listen_fds = NULL, n, i, serv_port;
+ unsigned int num_listens = 5;
+ char buf[1];
+
+ /* Start reuseport servers. */
+ listen_fds = start_reuseport_server(AF_INET6, SOCK_DGRAM,
+ "::1", 0, 0, num_listens);
+ if (!ASSERT_OK_PTR(listen_fds, "start_reuseport_server"))
+ goto cleanup;
+ serv_port = get_socket_local_port(listen_fds[0]);
+ if (!ASSERT_GE(serv_port, 0, "get_sock_local_port"))
+ goto cleanup;
+ skel->bss->serv_port = (__be16) serv_port;
+
+ /* Run iterator program that destroys server sockets. */
+ start_iter_sockets(skel->progs.iter_udp6_server);
+
+ for (i = 0; i < num_listens; ++i) {
+ n = read(listen_fds[i], buf, sizeof(buf));
+ if (!ASSERT_EQ(n, -1, "read") ||
+ !ASSERT_EQ(errno, ECONNABORTED, "error code on destroyed socket"))
+ break;
+ }
+ ASSERT_EQ(i, num_listens, "server socket");
+
+cleanup:
+ free_fds(listen_fds, num_listens);
+}
+
+void test_sock_destroy(void)
+{
+ struct sock_destroy_prog *skel;
+ struct nstoken *nstoken = NULL;
+ int cgroup_fd;
+
+ skel = sock_destroy_prog__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "skel_open"))
+ return;
+
+ cgroup_fd = test__join_cgroup("/sock_destroy");
+ if (!ASSERT_GE(cgroup_fd, 0, "join_cgroup"))
+ goto cleanup;
+
+ skel->links.sock_connect = bpf_program__attach_cgroup(
+ skel->progs.sock_connect, cgroup_fd);
+ if (!ASSERT_OK_PTR(skel->links.sock_connect, "prog_attach"))
+ goto cleanup;
+
+ SYS(cleanup, "ip netns add %s", TEST_NS);
+ SYS(cleanup, "ip -net %s link set dev lo up", TEST_NS);
+
+ nstoken = open_netns(TEST_NS);
+ if (!ASSERT_OK_PTR(nstoken, "open_netns"))
+ goto cleanup;
+
+ if (test__start_subtest("tcp_client"))
+ test_tcp_client(skel);
+ if (test__start_subtest("tcp_server"))
+ test_tcp_server(skel);
+ if (test__start_subtest("udp_client"))
+ test_udp_client(skel);
+ if (test__start_subtest("udp_server"))
+ test_udp_server(skel);
+
+ RUN_TESTS(sock_destroy_prog_fail);
+
+cleanup:
+ if (nstoken)
+ close_netns(nstoken);
+ SYS_NOFAIL("ip netns del " TEST_NS " &> /dev/null");
+ if (cgroup_fd >= 0)
+ close(cgroup_fd);
+ sock_destroy_prog__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/sock_destroy_prog.c b/tools/testing/selftests/bpf/progs/sock_destroy_prog.c
new file mode 100644
index 000000000000..9e0bf7a54cec
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/sock_destroy_prog.c
@@ -0,0 +1,145 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_endian.h>
+
+#include "bpf_tracing_net.h"
+
+__be16 serv_port = 0;
+
+int bpf_sock_destroy(struct sock_common *sk) __ksym;
+
+struct {
+ __uint(type, BPF_MAP_TYPE_ARRAY);
+ __uint(max_entries, 1);
+ __type(key, __u32);
+ __type(value, __u64);
+} tcp_conn_sockets SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_ARRAY);
+ __uint(max_entries, 1);
+ __type(key, __u32);
+ __type(value, __u64);
+} udp_conn_sockets SEC(".maps");
+
+SEC("cgroup/connect6")
+int sock_connect(struct bpf_sock_addr *ctx)
+{
+ __u64 sock_cookie = 0;
+ int key = 0;
+ __u32 keyc = 0;
+
+ if (ctx->family != AF_INET6 || ctx->user_family != AF_INET6)
+ return 1;
+
+ sock_cookie = bpf_get_socket_cookie(ctx);
+ if (ctx->protocol == IPPROTO_TCP)
+ bpf_map_update_elem(&tcp_conn_sockets, &key, &sock_cookie, 0);
+ else if (ctx->protocol == IPPROTO_UDP)
+ bpf_map_update_elem(&udp_conn_sockets, &keyc, &sock_cookie, 0);
+ else
+ return 1;
+
+ return 1;
+}
+
+SEC("iter/tcp")
+int iter_tcp6_client(struct bpf_iter__tcp *ctx)
+{
+ struct sock_common *sk_common = ctx->sk_common;
+ __u64 sock_cookie = 0;
+ __u64 *val;
+ int key = 0;
+
+ if (!sk_common)
+ return 0;
+
+ if (sk_common->skc_family != AF_INET6)
+ return 0;
+
+ sock_cookie = bpf_get_socket_cookie(sk_common);
+ val = bpf_map_lookup_elem(&tcp_conn_sockets, &key);
+ if (!val)
+ return 0;
+ /* Destroy connected client sockets. */
+ if (sock_cookie == *val)
+ bpf_sock_destroy(sk_common);
+
+ return 0;
+}
+
+SEC("iter/tcp")
+int iter_tcp6_server(struct bpf_iter__tcp *ctx)
+{
+ struct sock_common *sk_common = ctx->sk_common;
+ const struct inet_connection_sock *icsk;
+ const struct inet_sock *inet;
+ struct tcp6_sock *tcp_sk;
+ __be16 srcp;
+
+ if (!sk_common)
+ return 0;
+
+ if (sk_common->skc_family != AF_INET6)
+ return 0;
+
+ tcp_sk = bpf_skc_to_tcp6_sock(sk_common);
+ if (!tcp_sk)
+ return 0;
+
+ icsk = &tcp_sk->tcp.inet_conn;
+ inet = &icsk->icsk_inet;
+ srcp = inet->inet_sport;
+
+ /* Destroy server sockets. */
+ if (srcp == serv_port)
+ bpf_sock_destroy(sk_common);
+
+ return 0;
+}
+
+
+SEC("iter/udp")
+int iter_udp6_client(struct bpf_iter__udp *ctx)
+{
+ struct udp_sock *udp_sk = ctx->udp_sk;
+ struct sock *sk = (struct sock *) udp_sk;
+ __u64 sock_cookie = 0, *val;
+ int key = 0;
+
+ if (!sk)
+ return 0;
+
+ sock_cookie = bpf_get_socket_cookie(sk);
+ val = bpf_map_lookup_elem(&udp_conn_sockets, &key);
+ if (!val)
+ return 0;
+ /* Destroy connected client sockets. */
+ if (sock_cookie == *val)
+ bpf_sock_destroy((struct sock_common *)sk);
+
+ return 0;
+}
+
+SEC("iter/udp")
+int iter_udp6_server(struct bpf_iter__udp *ctx)
+{
+ struct udp_sock *udp_sk = ctx->udp_sk;
+ struct sock *sk = (struct sock *) udp_sk;
+ struct inet_sock *inet;
+ __be16 srcp;
+
+ if (!sk)
+ return 0;
+
+ inet = &udp_sk->inet;
+ srcp = inet->inet_sport;
+ if (srcp == serv_port)
+ bpf_sock_destroy((struct sock_common *)sk);
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/progs/sock_destroy_prog_fail.c b/tools/testing/selftests/bpf/progs/sock_destroy_prog_fail.c
new file mode 100644
index 000000000000..dd6850b58e25
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/sock_destroy_prog_fail.c
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "vmlinux.h"
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_helpers.h>
+
+#include "bpf_misc.h"
+
+char _license[] SEC("license") = "GPL";
+
+int bpf_sock_destroy(struct sock_common *sk) __ksym;
+
+SEC("tp_btf/tcp_destroy_sock")
+__failure __msg("calling kernel function bpf_sock_destroy is not allowed")
+int BPF_PROG(trace_tcp_destroy_sock, struct sock *sk)
+{
+ /* should not load */
+ bpf_sock_destroy((struct sock_common *)sk);
+
+ return 0;
+}
+