The test cases for TCP and UDP iterators mirror the intended usages of the
helper.
The destroy helpers set `ECONNABORTED` error code that we can validate in the
test code with client sockets. But UDP sockets have an overriding error code
from the disconnect called during abort, so the error code the validation is
only done for TCP sockets.
The `struct sock` is redefined as vmlinux.h forward declares the struct, and the
loader fails to load the program as it finds the BTF FWD type for the struct
incompatible with the BTF STRUCT type.
Here are the snippets of the verifier error, and corresponding BTF output:
```
verifier error: extern (func ksym) ...: func_proto ... incompatible with kernel
BTF for selftest prog binary:
[104] FWD 'sock' fwd_kind=struct
[70] PTR '(anon)' type_id=104
[84] FUNC_PROTO '(anon)' ret_type_id=2 vlen=1
'(anon)' type_id=70
[85] FUNC 'bpf_sock_destroy' type_id=84 linkage=extern
--
[96] DATASEC '.ksyms' size=0 vlen=1
type_id=85 offset=0 size=0 (FUNC 'bpf_sock_destroy')
BTF for selftest vmlinux:
[74923] FUNC 'bpf_sock_destroy' type_id=48965 linkage=static
[48965] FUNC_PROTO '(anon)' ret_type_id=9 vlen=1
'sk' type_id=1340
[1340] PTR '(anon)' type_id=2363
[2363] STRUCT 'sock' size=1280 vlen=93
```
Signed-off-by: Aditi Ghag <aditi.ghag@xxxxxxxxxxxxx>
---
.../selftests/bpf/prog_tests/sock_destroy.c | 125 ++++++++++++++++++
.../selftests/bpf/progs/sock_destroy_prog.c | 110 +++++++++++++++
2 files changed, 235 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/sock_destroy.c
create mode 100644 tools/testing/selftests/bpf/progs/sock_destroy_prog.c
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..d9da9d3578e2
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/sock_destroy.c
@@ -0,0 +1,125 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+
+#include "sock_destroy_prog.skel.h"
+#include "network_helpers.h"
+
+#define ECONNABORTED 103
+
+static int duration;
+
+static void start_iter_sockets(struct bpf_program *prog)
+{
+ struct bpf_link *link;
+ char buf[16] = {};
+ 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)
+ ;
+ CHECK(len < 0, "read", "read failed: %s\n", strerror(errno));
+
+ close(iter_fd);
+
+free_link:
+ bpf_link__destroy(link);
+}
+
+void test_tcp(struct sock_destroy_prog *skel)
+{
+ int serv = -1, clien = -1, n = 0;
+
+ serv = start_server(AF_INET6, SOCK_STREAM, NULL, 0, 0);
+ if (CHECK(serv < 0, "start_server", "failed to start server\n"))
+ goto cleanup_serv;
+
+ clien = connect_to_fd(serv, 0);
+ if (CHECK(clien < 0, "connect_to_fd", "errno %d\n", errno))
+ goto cleanup_serv;
+
+ serv = accept(serv, NULL, NULL);
+ if (CHECK(serv < 0, "accept", "errno %d\n", errno))
+ goto cleanup;
+
+ n = send(clien, "t", 1, 0);
+ if (CHECK(n < 0, "client_send", "client failed to send on socket\n"))
+ goto cleanup;
+
+ start_iter_sockets(skel->progs.iter_tcp6);
+
+ n = send(clien, "t", 1, 0);
+ if (CHECK(n > 0, "client_send after destroy", "succeeded on destroyed socket\n"))
+ goto cleanup;
+ CHECK(errno != ECONNABORTED, "client_send", "unexpected error code on destroyed socket\n");
+
+
+cleanup:
+ close(clien);
+cleanup_serv:
+ close(serv);
+}
+
+
+void test_udp(struct sock_destroy_prog *skel)
+{
+ int serv = -1, clien = -1, n = 0;
+
+ serv = start_server(AF_INET6, SOCK_DGRAM, NULL, 6161, 0);
+ if (CHECK(serv < 0, "start_server", "failed to start server\n"))
+ goto cleanup_serv;
+
+ clien = connect_to_fd(serv, 0);
+ if (CHECK(clien < 0, "connect_to_fd", "errno %d\n", errno))
+ goto cleanup_serv;
+
+ n = send(clien, "t", 1, 0);
+ if (CHECK(n < 0, "client_send", "client failed to send on socket\n"))
+ goto cleanup;
+
+ start_iter_sockets(skel->progs.iter_udp6);
+
+ n = send(clien, "t", 1, 0);
+ if (CHECK(n > 0, "client_send after destroy", "succeeded on destroyed socket\n"))
+ goto cleanup;
+ // UDP sockets have an overriding error code after they are disconnected.
+
+
+cleanup:
+ close(clien);
+cleanup_serv:
+ close(serv);
+}
+
+void test_sock_destroy(void)
+{
+ int cgroup_fd = 0;
+ struct sock_destroy_prog *skel;
+
+ skel = sock_destroy_prog__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "skel_open"))
+ return;
+
+ cgroup_fd = test__join_cgroup("/sock_destroy");
+ if (CHECK(cgroup_fd < 0, "join_cgroup", "cgroup creation failed\n"))
+ goto close_cgroup_fd;
+
+ 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 close_cgroup_fd;
+
+ test_tcp(skel);
+ test_udp(skel);
+
+
+close_cgroup_fd:
+ 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..c6805a9b7594
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/sock_destroy_prog.c
@@ -0,0 +1,110 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define sock sock___not_used
+#include "vmlinux.h"
+#undef sock
+
+#include <bpf/bpf_helpers.h>
+
+#define AF_INET6 10
+
+/* Redefine the struct: vmlinux.h forward declares it, and the loader fails
+ * to load the program as it finds the BTF FWD type for the struct incompatible
+ * with the BTF STRUCT type.
+ */
+struct sock {
+ struct sock_common __sk_common;
+#define sk_family __sk_common.skc_family
+#define sk_cookie __sk_common.skc_cookie
+};
+
+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)
+{
+ int key = 0;
+ __u64 sock_cookie = 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(struct bpf_iter__tcp *ctx)
+{
+ struct sock_common *sk_common = ctx->sk_common;
+ struct seq_file *seq = ctx->meta->seq;
+ __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;
+
+ if (sock_cookie == *val)
+ bpf_sock_destroy(sk_common);
+
+ return 0;
+}
+
+SEC("iter/udp")
+int iter_udp6(struct bpf_iter__udp *ctx)
+{
+ struct seq_file *seq = ctx->meta->seq;
+ struct udp_sock *udp_sk = ctx->udp_sk;
+ struct sock *sk = (struct sock *) udp_sk;
+ __u64 sock_cookie = 0;
+ int key = 0;
+ __u64 *val;
+
+ if (!sk)
+ return 0;
+
+ sock_cookie = bpf_get_socket_cookie(sk);
+ val = bpf_map_lookup_elem(&udp_conn_sockets, &key);
+
+ if (!val)
+ return 0;
+
+ if (sock_cookie == *val)
+ bpf_sock_destroy((struct sock_common *)sk);
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
--
2.34.1
