bpf: convert sockmap field attach_bpf_fd2 to type

In the initial sockmap API we provided strparser and verdict programs
using a single attach command by extending the attach API with a the
attach_bpf_fd2 field.

However, if we add other programs in the future we will be adding a
field for every new possible type, attach_bpf_fd(3,4,..). This
seems a bit clumsy for an API. So lets push the programs using two
new type fields.

   BPF_SK_SKB_STREAM_PARSER
   BPF_SK_SKB_STREAM_VERDICT

This has the advantage of having a readable name and can easily be
extended in the future.

Updates to samples and sockmap included here also generalize tests
slightly to support upcoming patch for multiple map support.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Fixes: 174a79ff9515 ("bpf: sockmap with sk redirect support")
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 25 insertions, 38 deletions

diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c
index 617c239..cf570d1 100644
--- a/kernel/bpf/sockmap.c
+++ b/kernel/bpf/sockmap.c
@@ -723,20 +723,24 @@ out:
 	return err;
 }
 
-static int sock_map_attach_prog(struct bpf_map *map,
-				struct bpf_prog *parse,
-				struct bpf_prog *verdict)
+int sock_map_attach_prog(struct bpf_map *map, struct bpf_prog *prog, u32 type)
 {
 	struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
-	struct bpf_prog *_parse, *_verdict;
+	struct bpf_prog *orig;
 
-	_parse = xchg(&stab->bpf_parse, parse);
-	_verdict = xchg(&stab->bpf_verdict, verdict);
+	switch (type) {
+	case BPF_SK_SKB_STREAM_PARSER:
+		orig = xchg(&stab->bpf_parse, prog);
+		break;
+	case BPF_SK_SKB_STREAM_VERDICT:
+		orig = xchg(&stab->bpf_verdict, prog);
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
 
-	if (_parse)
-		bpf_prog_put(_parse);
-	if (_verdict)
-		bpf_prog_put(_verdict);
+	if (orig)
+		bpf_prog_put(orig);
 
 	return 0;
 }
@@ -777,7 +781,6 @@ const struct bpf_map_ops sock_map_ops = {
 	.map_get_next_key = sock_map_get_next_key,
 	.map_update_elem = sock_map_update_elem,
 	.map_delete_elem = sock_map_delete_elem,
-	.map_attach = sock_map_attach_prog,
 };
 
 BPF_CALL_5(bpf_sock_map_update, struct bpf_sock_ops_kern *, bpf_sock,
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 9378f3b..021a05d 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1093,12 +1093,12 @@ static int bpf_obj_get(const union bpf_attr *attr)
 
 #ifdef CONFIG_CGROUP_BPF
 
-#define BPF_PROG_ATTACH_LAST_FIELD attach_bpf_fd2
+#define BPF_PROG_ATTACH_LAST_FIELD attach_flags
 
-static int sockmap_get_from_fd(const union bpf_attr *attr, int ptype)
+static int sockmap_get_from_fd(const union bpf_attr *attr)
 {
-	struct bpf_prog *prog1, *prog2;
 	int ufd = attr->target_fd;
+	struct bpf_prog *prog;
 	struct bpf_map *map;
 	struct fd f;
 	int err;
@@ -1108,29 +1108,16 @@ static int sockmap_get_from_fd(const union bpf_attr *attr, int ptype)
 	if (IS_ERR(map))
 		return PTR_ERR(map);
 
-	if (!map->ops->map_attach) {
-		fdput(f);
-		return -EOPNOTSUPP;
-	}
-
-	prog1 = bpf_prog_get_type(attr->attach_bpf_fd, ptype);
-	if (IS_ERR(prog1)) {
+	prog = bpf_prog_get_type(attr->attach_bpf_fd, BPF_PROG_TYPE_SK_SKB);
+	if (IS_ERR(prog)) {
 		fdput(f);
-		return PTR_ERR(prog1);
-	}
-
-	prog2 = bpf_prog_get_type(attr->attach_bpf_fd2, ptype);
-	if (IS_ERR(prog2)) {
-		fdput(f);
-		bpf_prog_put(prog1);
-		return PTR_ERR(prog2);
+		return PTR_ERR(prog);
 	}
 
-	err = map->ops->map_attach(map, prog1, prog2);
+	err = sock_map_attach_prog(map, prog, attr->attach_type);
 	if (err) {
 		fdput(f);
-		bpf_prog_put(prog1);
-		bpf_prog_put(prog2);
+		bpf_prog_put(prog);
 		return err;
 	}
 
@@ -1165,16 +1152,13 @@ static int bpf_prog_attach(const union bpf_attr *attr)
 	case BPF_CGROUP_SOCK_OPS:
 		ptype = BPF_PROG_TYPE_SOCK_OPS;
 		break;
-	case BPF_CGROUP_SMAP_INGRESS:
-		ptype = BPF_PROG_TYPE_SK_SKB;
-		break;
+	case BPF_SK_SKB_STREAM_PARSER:
+	case BPF_SK_SKB_STREAM_VERDICT:
+		return sockmap_get_from_fd(attr);
 	default:
 		return -EINVAL;
 	}
 
-	if (attr->attach_type == BPF_CGROUP_SMAP_INGRESS)
-		return sockmap_get_from_fd(attr, ptype);
-
 	prog = bpf_prog_get_type(attr->attach_bpf_fd, ptype);
 	if (IS_ERR(prog))
 		return PTR_ERR(prog);