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 <[e-mail]>
Fixes: 174a79ff9515 ("bpf: sockmap with sk redirect support")
Suggested-by: Alexei Starovoitov <[e-mail]>
Acked-by: Alexei Starovoitov <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/linux/bpf.h

···
 	void (*map_fd_put_ptr)(void *ptr);
 	u32 (*map_gen_lookup)(struct bpf_map *map, struct bpf_insn *insn_buf);
 	u32 (*map_fd_sys_lookup_elem)(void *ptr);
-	int (*map_attach)(struct bpf_map *map,
-			  struct bpf_prog *p1, struct bpf_prog *p2);
 };
 
 struct bpf_map {
···
 
 #if defined(CONFIG_STREAM_PARSER) && defined(CONFIG_BPF_SYSCALL)
 struct sock  *__sock_map_lookup_elem(struct bpf_map *map, u32 key);
+int sock_map_attach_prog(struct bpf_map *map, struct bpf_prog *prog, u32 type);
 #else
 static inline struct sock  *__sock_map_lookup_elem(struct bpf_map *map, u32 key)
 {
 	return NULL;
+}
+
+static inline int sock_map_attach_prog(struct bpf_map *map,
+				       struct bpf_prog *prog,
+				       u32 type)
+{
+	return -EOPNOTSUPP;
 }
 #endif
 

include/uapi/linux/bpf.h

···
 	BPF_CGROUP_INET_EGRESS,
 	BPF_CGROUP_INET_SOCK_CREATE,
 	BPF_CGROUP_SOCK_OPS,
-	BPF_CGROUP_SMAP_INGRESS,
+	BPF_SK_SKB_STREAM_PARSER,
+	BPF_SK_SKB_STREAM_VERDICT,
 	__MAX_BPF_ATTACH_TYPE
 };
 
···
 		__u32		attach_bpf_fd;	/* eBPF program to attach */
 		__u32		attach_type;
 		__u32		attach_flags;
-		__u32		attach_bpf_fd2;
 	};
 
 	struct { /* anonymous struct used by BPF_PROG_TEST_RUN command */
···
  *     @flags: reserved for future use
  *     Return: SK_REDIRECT
  *
- * int bpf_sock_map_update(skops, map, key, flags, map_flags)
+ * int bpf_sock_map_update(skops, map, key, flags)
  *	@skops: pointer to bpf_sock_ops
  *	@map: pointer to sockmap to update
  *	@key: key to insert/update sock in map
  *	@flags: same flags as map update elem
- *	@map_flags: sock map specific flags
- *	   bit 1: Enable strparser
- *	   other bits: reserved
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\

kernel/bpf/sockmap.c

···
 	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;
 }
···
 	.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,

kernel/bpf/syscall.c

···
 
 #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;
···
 	if (IS_ERR(map))
 		return PTR_ERR(map);
 
-	if (!map->ops->map_attach) {
+	prog = bpf_prog_get_type(attr->attach_bpf_fd, BPF_PROG_TYPE_SK_SKB);
+	if (IS_ERR(prog)) {
 		fdput(f);
-		return -EOPNOTSUPP;
+		return PTR_ERR(prog);
 	}
 
-	prog1 = bpf_prog_get_type(attr->attach_bpf_fd, ptype);
-	if (IS_ERR(prog1)) {
-		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);
-	}
-
-	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;
 	}
 
···
 	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))

samples/sockmap/sockmap_kern.c

···
 		if (lport == 10000) {
 			ret = 1;
 			err = bpf_sock_map_update(skops, &sock_map, &ret,
-						  BPF_NOEXIST,
-						  BPF_SOCKMAP_STRPARSER);
+						  BPF_NOEXIST);
 			bpf_printk("passive(%i -> %i) map ctx update err: %d\n",
 				   lport, bpf_ntohl(rport), err);
 		}
···
 		if (bpf_ntohl(rport) == 10001) {
 			ret = 10;
 			err = bpf_sock_map_update(skops, &sock_map, &ret,
-						  BPF_NOEXIST,
-						  BPF_SOCKMAP_STRPARSER);
+						  BPF_NOEXIST);
 			bpf_printk("active(%i -> %i) map ctx update err: %d\n",
 				   lport, bpf_ntohl(rport), err);
 		}

samples/sockmap/sockmap_user.c

···
 	}
 
 	/* Attach programs to sockmap */
-	err = __bpf_prog_attach(prog_fd[0], prog_fd[1], map_fd[0],
-				BPF_CGROUP_SMAP_INGRESS, 0);
+	err = bpf_prog_attach(prog_fd[0], map_fd[0],
+				BPF_SK_SKB_STREAM_PARSER, 0);
+	if (err) {
+		fprintf(stderr, "ERROR: bpf_prog_attach (sockmap): %d (%s)\n",
+			err, strerror(errno));
+		return err;
+	}
+
+	err = bpf_prog_attach(prog_fd[1], map_fd[0],
+				BPF_SK_SKB_STREAM_VERDICT, 0);
 	if (err) {
 		fprintf(stderr, "ERROR: bpf_prog_attach (sockmap): %d (%s)\n",
 			err, strerror(errno));

tools/include/uapi/linux/bpf.h

···
 	BPF_CGROUP_INET_EGRESS,
 	BPF_CGROUP_INET_SOCK_CREATE,
 	BPF_CGROUP_SOCK_OPS,
-	BPF_CGROUP_SMAP_INGRESS,
+	BPF_SK_SKB_STREAM_PARSER,
+	BPF_SK_SKB_STREAM_VERDICT,
 	__MAX_BPF_ATTACH_TYPE
 };
 
···
 		__u32		attach_bpf_fd;	/* eBPF program to attach */
 		__u32		attach_type;
 		__u32		attach_flags;
-		__u32		attach_bpf_fd2;
 	};
 
 	struct { /* anonymous struct used by BPF_PROG_TEST_RUN command */
···
  *     @flags: reserved for future use
  *     Return: SK_REDIRECT
  *
- * int bpf_sock_map_update(skops, map, key, flags, map_flags)
+ * int bpf_sock_map_update(skops, map, key, flags)
  *	@skops: pointer to bpf_sock_ops
  *	@map: pointer to sockmap to update
  *	@key: key to insert/update sock in map
  *	@flags: same flags as map update elem
- *	@map_flags: sock map specific flags
- *	   bit 1: Enable strparser
- *	   other bits: reserved
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\

tools/lib/bpf/bpf.c

···
 	return sys_bpf(BPF_OBJ_GET, &attr, sizeof(attr));
 }
 
-int __bpf_prog_attach(int prog_fd1, int prog_fd2, int target_fd,
-		      enum bpf_attach_type type,
-		      unsigned int flags)
+int bpf_prog_attach(int prog_fd, int target_fd, enum bpf_attach_type type,
+		    unsigned int flags)
 {
 	union bpf_attr attr;
 
 	bzero(&attr, sizeof(attr));
 	attr.target_fd	   = target_fd;
-	attr.attach_bpf_fd = prog_fd1;
-	attr.attach_bpf_fd2 = prog_fd2;
+	attr.attach_bpf_fd = prog_fd;
 	attr.attach_type   = type;
 	attr.attach_flags  = flags;
 
 	return sys_bpf(BPF_PROG_ATTACH, &attr, sizeof(attr));
-}
-
-int bpf_prog_attach(int prog_fd, int target_fd, enum bpf_attach_type type,
-		    unsigned int flags)
-{
-	return __bpf_prog_attach(prog_fd, 0, target_fd, type, flags);
 }
 
 int bpf_prog_detach(int target_fd, enum bpf_attach_type type)

tools/lib/bpf/bpf.h

···
 int bpf_obj_get(const char *pathname);
 int bpf_prog_attach(int prog_fd, int attachable_fd, enum bpf_attach_type type,
 		    unsigned int flags);
-int __bpf_prog_attach(int prog1, int prog2,
-		      int attachable_fd,
-		      enum bpf_attach_type type,
-		      unsigned int flags);
 int bpf_prog_detach(int attachable_fd, enum bpf_attach_type type);
 int bpf_prog_test_run(int prog_fd, int repeat, void *data, __u32 size,
 		      void *data_out, __u32 *size_out, __u32 *retval,

tools/testing/selftests/bpf/bpf_helpers.h

···
 static int (*bpf_sk_redirect_map)(void *map, int key, int flags) =
 	(void *) BPF_FUNC_sk_redirect_map;
 static int (*bpf_sock_map_update)(void *map, void *key, void *value,
-				  unsigned long long flags,
-				  unsigned long long map_lags) =
+				  unsigned long long flags) =
 	(void *) BPF_FUNC_sock_map_update;
 
 

tools/testing/selftests/bpf/sockmap_parse_prog.c

···
 	 */
 	d[0] = 1;
 
-	bpf_printk("data[0] = (%u): local_port %i remote %i\n",
+	bpf_printk("parse: data[0] = (%u): local_port %i remote %i\n",
 		   d[0], lport, bpf_ntohl(rport));
 	return skb->len;
 }

tools/testing/selftests/bpf/sockmap_verdict_prog.c

···
 	d[6] = 0xe;
 	d[7] = 0xf;
 
-	bpf_printk("data[0] = (%u): local_port %i remote %i\n",
+	bpf_printk("verdict: data[0] = (%u): local_port %i remote %i redirect 5\n",
 		   d[0], lport, bpf_ntohl(rport));
 	return bpf_sk_redirect_map(&sock_map, 5, 0);
 }

tools/testing/selftests/bpf/test_maps.c

···
 		goto out_sockmap;
 	}
 
-	/* Nothing attached so these should fail */
+	/* Test update without programs */
 	for (i = 0; i < 6; i++) {
 		err = bpf_map_update_elem(fd, &i, &sfd[i], BPF_ANY);
-		if (!err) {
-			printf("Failed invalid update sockmap '%i:%i'\n",
+		if (err) {
+			printf("Failed noprog update sockmap '%i:%i'\n",
 			       i, sfd[i]);
 			goto out_sockmap;
 		}
 	}
 
 	/* Test attaching bad fds */
-	err = __bpf_prog_attach(-1, -2, fd, BPF_CGROUP_SMAP_INGRESS, 0);
+	err = bpf_prog_attach(-1, fd, BPF_SK_SKB_STREAM_PARSER, 0);
 	if (!err) {
-		printf("Failed invalid prog attach\n");
+		printf("Failed invalid parser prog attach\n");
+		goto out_sockmap;
+	}
+
+	err = bpf_prog_attach(-1, fd, BPF_SK_SKB_STREAM_VERDICT, 0);
+	if (!err) {
+		printf("Failed invalid verdict prog attach\n");
 		goto out_sockmap;
 	}
 
···
 		goto out_sockmap;
 	}
 
-	err = __bpf_prog_attach(parse_prog, verdict_prog, map_fd,
-				BPF_CGROUP_SMAP_INGRESS, 0);
+	err = bpf_prog_attach(parse_prog, map_fd,
+		      BPF_SK_SKB_STREAM_PARSER, 0);
 	if (err) {
 		printf("Failed bpf prog attach\n");
 		goto out_sockmap;
 	}
 
-	/* Test map update elem */
+	err = bpf_prog_attach(verdict_prog, map_fd,
+			      BPF_SK_SKB_STREAM_VERDICT, 0);
+	if (err) {
+		printf("Failed bpf prog attach\n");
+		goto out_sockmap;
+	}
+
+	/* Test map update elem afterwards fd lives in fd and map_fd */
 	for (i = 0; i < 6; i++) {
 		err = bpf_map_update_elem(map_fd, &i, &sfd[i], BPF_ANY);
 		if (err) {
···
 		goto out_sockmap;
 	}
 
-	/* Delete the reset of the elems include some NULL elems */
-	for (i = 0; i < 6; i++) {
-		err = bpf_map_delete_elem(map_fd, &i);
-		if (err && (i == 0 || i == 1 || i >= 4)) {
-			printf("Failed delete  sockmap %i '%i:%i'\n",
-			       err, i, sfd[i]);
-			goto out_sockmap;
-		} else if (!err && (i == 2 || i == 3)) {
-			printf("Failed null delete sockmap %i '%i:%i'\n",
-			       err, i, sfd[i]);
-			goto out_sockmap;
-		}
-	}
-
-	/* Test having multiple SMAPs open and active on same fds */
-	err = __bpf_prog_attach(parse_prog, verdict_prog, fd,
-				BPF_CGROUP_SMAP_INGRESS, 0);
-	if (err) {
-		printf("Failed fd bpf prog attach\n");
-		goto out_sockmap;
-	}
-
-	for (i = 0; i < 6; i++) {
-		err = bpf_map_update_elem(fd, &i, &sfd[i], BPF_ANY);
-		if (err) {
-			printf("Failed fd update sockmap %i '%i:%i'\n",
-			       err, i, sfd[i]);
-			goto out_sockmap;
-		}
-	}
-
-	/* Test duplicate socket add of NOEXIST, ANY and EXIST */
-	i = 0;
-	err = bpf_map_update_elem(fd, &i, &sfd[i], BPF_NOEXIST);
-	if (!err) {
-		printf("Failed BPF_NOEXIST create\n");
-		goto out_sockmap;
-	}
-
-	err = bpf_map_update_elem(fd, &i, &sfd[i], BPF_ANY);
-	if (err) {
-		printf("Failed sockmap update BPF_ANY\n");
-		goto out_sockmap;
-	}
-
-	err = bpf_map_update_elem(fd, &i, &sfd[i], BPF_EXIST);
-	if (err) {
-		printf("Failed sockmap update BPF_EXIST\n");
-		goto out_sockmap;
-	}
-
-	/* The above were pushing fd into same slot try different slot now */
+	/* Push fd into same slot */
 	i = 2;
 	err = bpf_map_update_elem(fd, &i, &sfd[i], BPF_NOEXIST);
 	if (!err) {
-		printf("Failed BPF_NOEXIST create\n");
+		printf("Failed allowed sockmap dup slot BPF_NOEXIST\n");
 		goto out_sockmap;
 	}
 
 	err = bpf_map_update_elem(fd, &i, &sfd[i], BPF_ANY);
 	if (err) {
-		printf("Failed sockmap update BPF_ANY\n");
+		printf("Failed sockmap update new slot BPF_ANY\n");
 		goto out_sockmap;
 	}
 
 	err = bpf_map_update_elem(fd, &i, &sfd[i], BPF_EXIST);
 	if (err) {
-		printf("Failed sockmap update BPF_EXIST\n");
+		printf("Failed sockmap update new slot BPF_EXIST\n");
 		goto out_sockmap;
 	}
 
-	/* Try pushing fd into different map, this is not allowed at the
-	 * moment. Which programs would we use?
-	 */
-	err = bpf_map_update_elem(map_fd, &i, &sfd[i], BPF_NOEXIST);
-	if (!err) {
-		printf("Failed BPF_NOEXIST create\n");
+	/* Delete the elems without programs */
+	for (i = 0; i < 6; i++) {
+		err = bpf_map_delete_elem(fd, &i);
+		if (err) {
+			printf("Failed delete sockmap %i '%i:%i'\n",
+			       err, i, sfd[i]);
+		}
+	}
+
+	/* Test having multiple maps open and set with programs on same fds */
+	err = bpf_prog_attach(parse_prog, fd,
+			      BPF_SK_SKB_STREAM_PARSER, 0);
+	if (err) {
+		printf("Failed fd bpf parse prog attach\n");
+		goto out_sockmap;
+	}
+	err = bpf_prog_attach(verdict_prog, fd,
+			      BPF_SK_SKB_STREAM_VERDICT, 0);
+	if (err) {
+		printf("Failed fd bpf verdict prog attach\n");
 		goto out_sockmap;
 	}
 
-	err = bpf_map_update_elem(map_fd, &i, &sfd[i], BPF_ANY);
-	if (!err) {
-		printf("Failed sockmap update BPF_ANY\n");
-		goto out_sockmap;
-	}
-
-	err = bpf_map_update_elem(map_fd, &i, &sfd[i], BPF_EXIST);
-	if (!err) {
-		printf("Failed sockmap update BPF_EXIST\n");
-		goto out_sockmap;
+	for (i = 4; i < 6; i++) {
+		err = bpf_map_update_elem(fd, &i, &sfd[i], BPF_ANY);
+		if (!err) {
+			printf("Failed allowed duplicate programs in update ANY sockmap %i '%i:%i'\n",
+			       err, i, sfd[i]);
+			goto out_sockmap;
+		}
+		err = bpf_map_update_elem(fd, &i, &sfd[i], BPF_NOEXIST);
+		if (!err) {
+			printf("Failed allowed duplicate program in update NOEXIST sockmap  %i '%i:%i'\n",
+			       err, i, sfd[i]);
+			goto out_sockmap;
+		}
+		err = bpf_map_update_elem(fd, &i, &sfd[i], BPF_EXIST);
+		if (!err) {
+			printf("Failed allowed duplicate program in update EXIST sockmap  %i '%i:%i'\n",
+			       err, i, sfd[i]);
+			goto out_sockmap;
+		}
 	}
 
 	/* Test map close sockets */