bpf: selftests add sockmap tests

This generates a set of sockets, attaches BPF programs, and sends some
simple traffic using basic send/recv pattern. Additionally, we do a bunch
of negative tests to ensure adding/removing socks out of the sockmap fail
correctly.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/lib/bpf/libbpf.c

@@ -1744,3 +1744,32 @@ long libbpf_get_error(const void *ptr)
 		return PTR_ERR(ptr);
 	return 0;
 }
+
+int bpf_prog_load(const char *file, enum bpf_prog_type type,
+		  struct bpf_object **pobj, int *prog_fd)
+{
+	struct bpf_program *prog;
+	struct bpf_object *obj;
+	int err;
+
+	obj = bpf_object__open(file);
+	if (IS_ERR(obj))
+		return -ENOENT;
+
+	prog = bpf_program__next(NULL, obj);
+	if (!prog) {
+		bpf_object__close(obj);
+		return -ENOENT;
+	}
+
+	bpf_program__set_type(prog, type);
+	err = bpf_object__load(obj);
+	if (err) {
+		bpf_object__close(obj);
+		return -EINVAL;
+	}
+
+	*pobj = obj;
+	*prog_fd = bpf_program__fd(prog);
+	return 0;
+}

tools/lib/bpf/libbpf.h

@@ -243,4 +243,6 @@ int bpf_map__pin(struct bpf_map *map, const char *path);
 
 long libbpf_get_error(const void *ptr);
 
+int bpf_prog_load(const char *file, enum bpf_prog_type type,
+		  struct bpf_object **pobj, int *prog_fd);
 #endif

tools/testing/selftests/bpf/Makefile

@@ -15,7 +15,7 @@ TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test
 	test_align
 
 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_pkt_md_access.o test_xdp_redirect.o sockmap_parse_prog.o sockmap_verdict_prog.o
 
 TEST_PROGS := test_kmod.sh test_xdp_redirect.sh
 

tools/testing/selftests/bpf/sockmap_parse_prog.c

@@ -0,0 +1,38 @@
+#include <linux/bpf.h>
+#include "bpf_helpers.h"
+#include "bpf_util.h"
+#include "bpf_endian.h"
+
+int _version SEC("version") = 1;
+
+#define bpf_printk(fmt, ...)					\
+({								\
+	       char ____fmt[] = fmt;				\
+	       bpf_trace_printk(____fmt, sizeof(____fmt),	\
+				##__VA_ARGS__);			\
+})
+
+SEC("sk_skb1")
+int bpf_prog1(struct __sk_buff *skb)
+{
+	void *data_end = (void *)(long) skb->data_end;
+	void *data = (void *)(long) skb->data;
+	__u32 lport = skb->local_port;
+	__u32 rport = skb->remote_port;
+	char *d = data;
+
+	if (data + 8 > data_end)
+		return skb->len;
+
+	/* This write/read is a bit pointless but tests the verifier and
+	 * strparser handler for read/write pkt data and access into sk
+	 * fields.
+	 */
+	d[0] = 1;
+
+	bpf_printk("data[0] = (%u): local_port %i remote %i\n",
+		   d[0], lport, bpf_ntohl(rport));
+	return skb->len;
+}
+
+char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/sockmap_verdict_prog.c

@@ -0,0 +1,48 @@
+#include <linux/bpf.h>
+#include "bpf_helpers.h"
+#include "bpf_util.h"
+#include "bpf_endian.h"
+
+int _version SEC("version") = 1;
+
+#define bpf_printk(fmt, ...)					\
+({								\
+	       char ____fmt[] = fmt;				\
+	       bpf_trace_printk(____fmt, sizeof(____fmt),	\
+				##__VA_ARGS__);			\
+})
+
+struct bpf_map_def SEC("maps") sock_map = {
+	.type = BPF_MAP_TYPE_SOCKMAP,
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.max_entries = 20,
+};
+
+SEC("sk_skb2")
+int bpf_prog2(struct __sk_buff *skb)
+{
+	void *data_end = (void *)(long) skb->data_end;
+	void *data = (void *)(long) skb->data;
+	__u32 lport = skb->local_port;
+	__u32 rport = skb->remote_port;
+	char *d = data;
+
+	if (data + 8 > data_end)
+		return SK_DROP;
+
+	d[0] = 0xd;
+	d[1] = 0xe;
+	d[2] = 0xa;
+	d[3] = 0xd;
+	d[4] = 0xb;
+	d[5] = 0xe;
+	d[6] = 0xe;
+	d[7] = 0xf;
+
+	bpf_printk("data[0] = (%u): local_port %i remote %i\n",
+		   d[0], lport, bpf_ntohl(rport));
+	return bpf_sk_redirect_map(&sock_map, 5, 0);
+}
+
+char _license[] SEC("license") = "GPL";