[bpf-next PATCH 2/2] bpf: test_maps add a test to catch kcm + sockmap

[John Fastabend <john.fastabend@gmail.com>]

Adding a socket to both sockmap and kcm is not supported due to
collision on sk_user_data usage.

If selftests is run without KCM support we will issue a warning
and continue with the tests.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
---
 tools/testing/selftests/bpf/Makefile      |    2 -
 tools/testing/selftests/bpf/sockmap_kcm.c |   14 ++++++
 tools/testing/selftests/bpf/test_maps.c   |   64 ++++++++++++++++++++++++++++-
 3 files changed, 77 insertions(+), 3 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/sockmap_kcm.c

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index d99dd6f..f290554 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -28,7 +28,7 @@ TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test
 
 TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test_obj_id.o \
 	test_pkt_md_access.o test_xdp_redirect.o test_xdp_meta.o sockmap_parse_prog.o     \
-	sockmap_verdict_prog.o dev_cgroup.o sample_ret0.o test_tracepoint.o \
+	sockmap_verdict_prog.o sockmap_kcm.o dev_cgroup.o sample_ret0.o test_tracepoint.o \
 	test_l4lb_noinline.o test_xdp_noinline.o test_stacktrace_map.o \
 	sample_map_ret0.o test_tcpbpf_kern.o test_stacktrace_build_id.o \
 	sockmap_tcp_msg_prog.o connect4_prog.o connect6_prog.o test_adjust_tail.o \
diff --git a/tools/testing/selftests/bpf/sockmap_kcm.c b/tools/testing/selftests/bpf/sockmap_kcm.c
new file mode 100644
index 0000000..4377adc
--- /dev/null
+++ b/tools/testing/selftests/bpf/sockmap_kcm.c
@@ -0,0 +1,14 @@
+#include <linux/bpf.h>
+#include "bpf_helpers.h"
+#include "bpf_util.h"
+#include "bpf_endian.h"
+
+int _version SEC("version") = 1;
+
+SEC("socket_kcm")
+int bpf_prog1(struct __sk_buff *skb)
+{
+	return skb->len;
+}
+
+char _license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/test_maps.c b/tools/testing/selftests/bpf/test_maps.c
index 9b552c0..be20f1d 100644
--- a/tools/testing/selftests/bpf/test_maps.c
+++ b/tools/testing/selftests/bpf/test_maps.c
@@ -20,6 +20,7 @@
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <linux/bpf.h>
+#include <linux/kcm.h>
 
 #include <bpf/bpf.h>
 #include <bpf/libbpf.h>
@@ -479,14 +480,16 @@ static void test_devmap(int task, void *data)
 #define SOCKMAP_PARSE_PROG "./sockmap_parse_prog.o"
 #define SOCKMAP_VERDICT_PROG "./sockmap_verdict_prog.o"
 #define SOCKMAP_TCP_MSG_PROG "./sockmap_tcp_msg_prog.o"
+#define KCM_PROG "./sockmap_kcm.o"
 static void test_sockmap(int tasks, void *data)
 {
 	struct bpf_map *bpf_map_rx, *bpf_map_tx, *bpf_map_msg, *bpf_map_break;
-	int map_fd_msg = 0, map_fd_rx = 0, map_fd_tx = 0, map_fd_break;
+	int map_fd_msg = 0, map_fd_rx = 0, map_fd_tx = 0, map_fd_break, kcm;
 	int ports[] = {50200, 50201, 50202, 50204};
 	int err, i, fd, udp, sfd[6] = {0xdeadbeef};
 	u8 buf[20] = {0x0, 0x5, 0x3, 0x2, 0x1, 0x0};
-	int parse_prog, verdict_prog, msg_prog;
+	int parse_prog, verdict_prog, msg_prog, kcm_prog;
+	struct kcm_attach attach_info;
 	struct sockaddr_in addr;
 	int one = 1, s, sc, rc;
 	struct bpf_object *obj;
@@ -744,6 +747,62 @@ static void test_sockmap(int tasks, void *data)
 		goto out_sockmap;
 	}
 
+	/* Test adding a KCM socket into map */
+#define AF_KCM 41
+	kcm = socket(AF_KCM, SOCK_DGRAM, KCMPROTO_CONNECTED);
+	if (kcm == -1) {
+		printf("Warning, KCM+Sockmap could not be tested.\n");
+		goto skip_kcm;
+	}
+
+	err = bpf_prog_load(KCM_PROG,
+			    BPF_PROG_TYPE_SOCKET_FILTER,
+			    &obj, &kcm_prog);
+	if (err) {
+		printf("Failed to load SK_SKB parse prog\n");
+		goto out_sockmap;
+	}
+
+	i = 2;
+	memset(&attach_info, 0, sizeof(attach_info));
+	attach_info.fd = sfd[i];
+	attach_info.bpf_fd = kcm_prog;
+	err = ioctl(kcm, SIOCKCMATTACH, &attach_info);
+	if (!err) {
+		perror("Failed KCM attached to sockmap fd: ");
+		goto out_sockmap;
+	}
+
+	err = bpf_map_delete_elem(fd, &i);
+	if (err) {
+		printf("Failed delete sockmap from empty map %i %i\n", err, errno);
+		goto out_sockmap;
+	}
+
+	err = ioctl(kcm, SIOCKCMATTACH, &attach_info);
+	if (err) {
+		perror("Failed KCM attach");
+		goto out_sockmap;
+	}
+
+	err = bpf_map_update_elem(fd, &i, &sfd[i], BPF_ANY);
+	if (!err) {
+		printf("Failed sockmap attached KCM sock!\n");
+		goto out_sockmap;
+	}
+	err = ioctl(kcm, SIOCKCMUNATTACH, &attach_info);
+	if (err) {
+		printf("Failed detach KCM sock!\n");
+		goto out_sockmap;
+	}
+
+	err = bpf_map_update_elem(fd, &i, &sfd[i], BPF_ANY);
+	if (err) {
+		printf("Failed post-kcm update sockmap '%i:%i'\n",
+		       i, sfd[i]);
+		goto out_sockmap;
+	}
+
 	/* Test map update elem afterwards fd lives in fd and map_fd */
 	for (i = 2; i < 6; i++) {
 		err = bpf_map_update_elem(map_fd_rx, &i, &sfd[i], BPF_ANY);
@@ -776,6 +835,7 @@ static void test_sockmap(int tasks, void *data)
 		}
 	}
 
+skip_kcm:
 	/* Put sfd[2] (sending fd below) into msg map to test sendmsg bpf */
 	i = 0;
 	err = bpf_map_update_elem(map_fd_msg, &i, &sfd[2], BPF_ANY);