bpf: bpftool, add support for attaching programs to maps

Sock map/hash introduce support for attaching programs to maps. To
date I have been doing this with custom tooling but this is less than
ideal as we shift to using bpftool as the single CLI for our BPF uses.
This patch adds new sub commands 'attach' and 'detach' to the 'prog'
command to attach programs to maps and then detach them.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

tools/bpf/bpftool/Documentation/bpftool-prog.rst

@@ -25,6 +25,8 @@ MAP COMMANDS
 |	**bpftool** **prog dump jited**  *PROG* [{**file** *FILE* | **opcodes**}]
 |	**bpftool** **prog pin** *PROG* *FILE*
 |	**bpftool** **prog load** *OBJ* *FILE* [**type** *TYPE*] [**map** {**idx** *IDX* | **name** *NAME*} *MAP*] [**dev** *NAME*]
+|       **bpftool** **prog attach** *PROG* *ATTACH_TYPE* *MAP*
+|       **bpftool** **prog detach** *PROG* *ATTACH_TYPE* *MAP*
 |	**bpftool** **prog help**
 |
 |	*MAP* := { **id** *MAP_ID* | **pinned** *FILE* }
@@ -37,6 +39,7 @@ MAP COMMANDS
 |		**cgroup/bind4** | **cgroup/bind6** | **cgroup/post_bind4** | **cgroup/post_bind6** |
 |		**cgroup/connect4** | **cgroup/connect6** | **cgroup/sendmsg4** | **cgroup/sendmsg6**
 |	}
+|       *ATTACH_TYPE* := { **msg_verdict** | **skb_verdict** | **skb_parse** }
 
 
 DESCRIPTION
@@ -90,6 +93,14 @@ DESCRIPTION
 
 		  Note: *FILE* must be located in *bpffs* mount.
 
+        **bpftool prog attach** *PROG* *ATTACH_TYPE* *MAP*
+                  Attach bpf program *PROG* (with type specified by *ATTACH_TYPE*)
+                  to the map *MAP*.
+
+        **bpftool prog detach** *PROG* *ATTACH_TYPE* *MAP*
+                  Detach bpf program *PROG* (with type specified by *ATTACH_TYPE*)
+                  from the map *MAP*.
+
 	**bpftool prog help**
 		  Print short help message.
 

tools/bpf/bpftool/Documentation/bpftool.rst

@@ -26,7 +26,7 @@ SYNOPSIS
 	| **pin** | **event_pipe** | **help** }
 
 	*PROG-COMMANDS* := { **show** | **list** | **dump jited** | **dump xlated** | **pin**
-	| **load** | **help** }
+	| **load** | **attach** | **detach** | **help** }
 
 	*CGROUP-COMMANDS* := { **show** | **list** | **attach** | **detach** | **help** }
 

tools/bpf/bpftool/bash-completion/bpftool

@@ -292,6 +292,23 @@ _bpftool()
                     fi
                     return 0
                     ;;
+                attach|detach)
+                    if [[ ${#words[@]} == 7 ]]; then
+                        COMPREPLY=( $( compgen -W "id pinned" -- "$cur" ) )
+                        return 0
+                    fi
+
+                    if [[ ${#words[@]} == 6 ]]; then
+                        COMPREPLY=( $( compgen -W "msg_verdict skb_verdict skb_parse" -- "$cur" ) )
+                        return 0
+                    fi
+
+                    if [[ $prev == "$command" ]]; then
+                        COMPREPLY=( $( compgen -W "id pinned" -- "$cur" ) )
+                        return 0
+                    fi
+                    return 0
+                    ;;
                 load)
                     local obj
 
@@ -347,7 +364,7 @@ _bpftool()
                     ;;
                 *)
                     [[ $prev == $object ]] && \
-                        COMPREPLY=( $( compgen -W 'dump help pin load \
+                        COMPREPLY=( $( compgen -W 'dump help pin attach detach load \
                             show list' -- "$cur" ) )
                     ;;
             esac

tools/bpf/bpftool/prog.c

@@ -77,6 +77,26 @@ static const char * const prog_type_name[] = {
 	[BPF_PROG_TYPE_FLOW_DISSECTOR]	= "flow_dissector",
 };
 
+static const char * const attach_type_strings[] = {
+	[BPF_SK_SKB_STREAM_PARSER] = "stream_parser",
+	[BPF_SK_SKB_STREAM_VERDICT] = "stream_verdict",
+	[BPF_SK_MSG_VERDICT] = "msg_verdict",
+	[__MAX_BPF_ATTACH_TYPE] = NULL,
+};
+
+enum bpf_attach_type parse_attach_type(const char *str)
+{
+	enum bpf_attach_type type;
+
+	for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++) {
+		if (attach_type_strings[type] &&
+		    is_prefix(str, attach_type_strings[type]))
+			return type;
+	}
+
+	return __MAX_BPF_ATTACH_TYPE;
+}
+
 static void print_boot_time(__u64 nsecs, char *buf, unsigned int size)
 {
 	struct timespec real_time_ts, boot_time_ts;
@@ -697,6 +717,77 @@ int map_replace_compar(const void *p1, const void *p2)
 	return a->idx - b->idx;
 }
 
+static int do_attach(int argc, char **argv)
+{
+	enum bpf_attach_type attach_type;
+	int err, mapfd, progfd;
+
+	if (!REQ_ARGS(5)) {
+		p_err("too few parameters for map attach");
+		return -EINVAL;
+	}
+
+	progfd = prog_parse_fd(&argc, &argv);
+	if (progfd < 0)
+		return progfd;
+
+	attach_type = parse_attach_type(*argv);
+	if (attach_type == __MAX_BPF_ATTACH_TYPE) {
+		p_err("invalid attach type");
+		return -EINVAL;
+	}
+	NEXT_ARG();
+
+	mapfd = map_parse_fd(&argc, &argv);
+	if (mapfd < 0)
+		return mapfd;
+
+	err = bpf_prog_attach(progfd, mapfd, attach_type, 0);
+	if (err) {
+		p_err("failed prog attach to map");
+		return -EINVAL;
+	}
+
+	if (json_output)
+		jsonw_null(json_wtr);
+	return 0;
+}
+
+static int do_detach(int argc, char **argv)
+{
+	enum bpf_attach_type attach_type;
+	int err, mapfd, progfd;
+
+	if (!REQ_ARGS(5)) {
+		p_err("too few parameters for map detach");
+		return -EINVAL;
+	}
+
+	progfd = prog_parse_fd(&argc, &argv);
+	if (progfd < 0)
+		return progfd;
+
+	attach_type = parse_attach_type(*argv);
+	if (attach_type == __MAX_BPF_ATTACH_TYPE) {
+		p_err("invalid attach type");
+		return -EINVAL;
+	}
+	NEXT_ARG();
+
+	mapfd = map_parse_fd(&argc, &argv);
+	if (mapfd < 0)
+		return mapfd;
+
+	err = bpf_prog_detach2(progfd, mapfd, attach_type);
+	if (err) {
+		p_err("failed prog detach from map");
+		return -EINVAL;
+	}
+
+	if (json_output)
+		jsonw_null(json_wtr);
+	return 0;
+}
 static int do_load(int argc, char **argv)
 {
 	enum bpf_attach_type expected_attach_type;
@@ -942,6 +1033,8 @@ static int do_help(int argc, char **argv)
 		"       %s %s pin   PROG FILE\n"
 		"       %s %s load  OBJ  FILE [type TYPE] [dev NAME] \\\n"
 		"                         [map { idx IDX | name NAME } MAP]\n"
+		"       %s %s attach PROG ATTACH_TYPE MAP\n"
+		"       %s %s detach PROG ATTACH_TYPE MAP\n"
 		"       %s %s help\n"
 		"\n"
 		"       " HELP_SPEC_MAP "\n"
@@ -953,10 +1046,12 @@ static int do_help(int argc, char **argv)
 		"                 cgroup/bind4 | cgroup/bind6 | cgroup/post_bind4 |\n"
 		"                 cgroup/post_bind6 | cgroup/connect4 | cgroup/connect6 |\n"
 		"                 cgroup/sendmsg4 | cgroup/sendmsg6 }\n"
+		"       ATTACH_TYPE := { msg_verdict | skb_verdict | skb_parse }\n"
 		"       " HELP_SPEC_OPTIONS "\n"
 		"",
 		bin_name, argv[-2], bin_name, argv[-2], bin_name, argv[-2],
-		bin_name, argv[-2], bin_name, argv[-2], bin_name, argv[-2]);
+		bin_name, argv[-2], bin_name, argv[-2], bin_name, argv[-2],
+		bin_name, argv[-2], bin_name, argv[-2]);
 
 	return 0;
 }
@@ -968,6 +1063,8 @@ static const struct cmd cmds[] = {
 	{ "dump",	do_dump },
 	{ "pin",	do_pin },
 	{ "load",	do_load },
+	{ "attach",	do_attach },
+	{ "detach",	do_detach },
 	{ 0 }
 };