bpftool: Use libbpf_bpf_attach_type_str

This change switches bpftool over to using the recently introduced
libbpf_bpf_attach_type_str function instead of maintaining its own
string representation for the bpf_attach_type enum.

Note that contrary to other enum types, the variant names that bpftool
maps bpf_attach_type to do not adhere a simple to follow rule. With
bpf_prog_type, for example, the textual representation can easily be
inferred by stripping the BPF_PROG_TYPE_ prefix and lowercasing the
remaining string. bpf_attach_type violates this rule for various
variants.
We decided to fix up this deficiency with this change, meaning that
bpftool uses the same textual representations as libbpf. Supporting
tests, completion scripts, and man pages have been adjusted accordingly.
However, we did add support for accepting (the now undocumented)
original attach type names when they are provided by users.

For the test (test_bpftool_synctypes.py), I have removed the enum
representation checks, because we no longer mirror the various enum
variant names in bpftool source code. For the man page, help text, and
completion script checks we are now using enum definitions from
uapi/linux/bpf.h as the source of truth directly.

Signed-off-by: Daniel Müller <deso@posteo.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20220523230428.3077108-10-deso@posteo.net

bash-completion/bpftool

@@ -407,8 +407,8 @@ _bpftool()
                             return 0
                             ;;
                         5)
-                            local BPFTOOL_PROG_ATTACH_TYPES='msg_verdict \
-                                skb_verdict stream_verdict stream_parser \
+                            local BPFTOOL_PROG_ATTACH_TYPES='sk_msg_verdict \
+                                sk_skb_verdict sk_skb_stream_verdict sk_skb_stream_parser \
                                 flow_dissector'
                             COMPREPLY=( $( compgen -W "$BPFTOOL_PROG_ATTACH_TYPES" -- "$cur" ) )
                             return 0
@@ -1039,12 +1039,14 @@ _bpftool()
                     return 0
                     ;;
                 attach|detach)
-                    local BPFTOOL_CGROUP_ATTACH_TYPES='ingress egress \
-                        sock_create sock_ops device \
-                        bind4 bind6 post_bind4 post_bind6 connect4 connect6 \
-                        getpeername4 getpeername6 getsockname4 getsockname6 \
-                        sendmsg4 sendmsg6 recvmsg4 recvmsg6 sysctl getsockopt \
-                        setsockopt sock_release'
+                    local BPFTOOL_CGROUP_ATTACH_TYPES='cgroup_inet_ingress cgroup_inet_egress \
+                        cgroup_inet_sock_create cgroup_sock_ops cgroup_device cgroup_inet4_bind \
+                        cgroup_inet6_bind cgroup_inet4_post_bind cgroup_inet6_post_bind \
+                        cgroup_inet4_connect cgroup_inet6_connect cgroup_inet4_getpeername \
+                        cgroup_inet6_getpeername cgroup_inet4_getsockname cgroup_inet6_getsockname \
+                        cgroup_udp4_sendmsg cgroup_udp6_sendmsg cgroup_udp4_recvmsg \
+                        cgroup_udp6_recvmsg cgroup_sysctl cgroup_getsockopt cgroup_setsockopt \
+                        cgroup_inet_sock_release'
                     local ATTACH_FLAGS='multi override'
                     local PROG_TYPE='id pinned tag name'
                     # Check for $prev = $command first

docs/bpftool-cgroup.rst

@@ -31,11 +31,17 @@ CGROUP COMMANDS
 |	**bpftool** **cgroup help**
 |
 |	*PROG* := { **id** *PROG_ID* | **pinned** *FILE* | **tag** *PROG_TAG* }
-|	*ATTACH_TYPE* := { **ingress** | **egress** | **sock_create** | **sock_ops** | **device** |
-|		**bind4** | **bind6** | **post_bind4** | **post_bind6** | **connect4** | **connect6** |
-|		**getpeername4** | **getpeername6** | **getsockname4** | **getsockname6** | **sendmsg4** |
-|		**sendmsg6** | **recvmsg4** | **recvmsg6** | **sysctl** | **getsockopt** | **setsockopt** |
-|		**sock_release** }
+|	*ATTACH_TYPE* := { **cgroup_inet_ingress** | **cgroup_inet_egress** |
+|		**cgroup_inet_sock_create** | **cgroup_sock_ops** |
+|		**cgroup_device** | **cgroup_inet4_bind** | **cgroup_inet6_bind** |
+|		**cgroup_inet4_post_bind** | **cgroup_inet6_post_bind** |
+|		**cgroup_inet4_connect** | **cgroup_inet6_connect** |
+|		**cgroup_inet4_getpeername** | **cgroup_inet6_getpeername** |
+|		**cgroup_inet4_getsockname** | **cgroup_inet6_getsockname** |
+|		**cgroup_udp4_sendmsg** | **cgroup_udp6_sendmsg** |
+|		**cgroup_udp4_recvmsg** | **cgroup_udp6_recvmsg** |
+|		**cgroup_sysctl** | **cgroup_getsockopt** | **cgroup_setsockopt** |
+|		**cgroup_inet_sock_release** }
 |	*ATTACH_FLAGS* := { **multi** | **override** }
 
 DESCRIPTION

docs/bpftool-prog.rst

@@ -53,8 +53,9 @@ PROG COMMANDS
 |		**cgroup/getsockopt** | **cgroup/setsockopt** | **cgroup/sock_release** |
 |		**struct_ops** | **fentry** | **fexit** | **freplace** | **sk_lookup**
 |	}
-|       *ATTACH_TYPE* := {
-|		**msg_verdict** | **skb_verdict** | **stream_verdict** | **stream_parser** | **flow_dissector**
+|	*ATTACH_TYPE* := {
+|		**sk_msg_verdict** | **sk_skb_verdict** | **sk_skb_stream_verdict** |
+|		**sk_skb_stream_parser** | **flow_dissector**
 |	}
 |	*METRICs* := {
 |		**cycles** | **instructions** | **l1d_loads** | **llc_misses** |

src/cgroup.c

@@ -21,25 +21,43 @@
 #define HELP_SPEC_ATTACH_FLAGS						\
 	"ATTACH_FLAGS := { multi | override }"
 
-#define HELP_SPEC_ATTACH_TYPES						       \
-	"       ATTACH_TYPE := { ingress | egress | sock_create |\n"	       \
-	"                        sock_ops | device | bind4 | bind6 |\n"	       \
-	"                        post_bind4 | post_bind6 | connect4 |\n"       \
-	"                        connect6 | getpeername4 | getpeername6 |\n"   \
-	"                        getsockname4 | getsockname6 | sendmsg4 |\n"   \
-	"                        sendmsg6 | recvmsg4 | recvmsg6 |\n"           \
-	"                        sysctl | getsockopt | setsockopt |\n"	       \
-	"                        sock_release }"
+#define HELP_SPEC_ATTACH_TYPES						\
+	"       ATTACH_TYPE := { cgroup_inet_ingress | cgroup_inet_egress |\n" \
+	"                        cgroup_inet_sock_create | cgroup_sock_ops |\n" \
+	"                        cgroup_device | cgroup_inet4_bind |\n" \
+	"                        cgroup_inet6_bind | cgroup_inet4_post_bind |\n" \
+	"                        cgroup_inet6_post_bind | cgroup_inet4_connect |\n" \
+	"                        cgroup_inet6_connect | cgroup_inet4_getpeername |\n" \
+	"                        cgroup_inet6_getpeername | cgroup_inet4_getsockname |\n" \
+	"                        cgroup_inet6_getsockname | cgroup_udp4_sendmsg |\n" \
+	"                        cgroup_udp6_sendmsg | cgroup_udp4_recvmsg |\n" \
+	"                        cgroup_udp6_recvmsg | cgroup_sysctl |\n" \
+	"                        cgroup_getsockopt | cgroup_setsockopt |\n" \
+	"                        cgroup_inet_sock_release }"
 
 static unsigned int query_flags;
 
 static enum bpf_attach_type parse_attach_type(const char *str)
 {
+	const char *attach_type_str;
 	enum bpf_attach_type type;
 
-	for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++) {
-		if (attach_type_name[type] &&
-		    is_prefix(str, attach_type_name[type]))
+	for (type = 0; ; type++) {
+		attach_type_str = libbpf_bpf_attach_type_str(type);
+		if (!attach_type_str)
+			break;
+		if (!strcmp(str, attach_type_str))
+			return type;
+	}
+
+	/* Also check traditionally used attach type strings. For these we keep
+	 * allowing prefixed usage.
+	 */
+	for (type = 0; ; type++) {
+		attach_type_str = bpf_attach_type_input_str(type);
+		if (!attach_type_str)
+			break;
+		if (is_prefix(str, attach_type_str))
 			return type;
 	}
 
@@ -52,6 +70,7 @@ static int show_bpf_prog(int id, enum bpf_attach_type attach_type,
 {
 	char prog_name[MAX_PROG_FULL_NAME];
 	struct bpf_prog_info info = {};
+	const char *attach_type_str;
 	__u32 info_len = sizeof(info);
 	int prog_fd;
 
@@ -64,13 +83,13 @@ static int show_bpf_prog(int id, enum bpf_attach_type attach_type,
 		return -1;
 	}
 
+	attach_type_str = libbpf_bpf_attach_type_str(attach_type);
 	get_prog_full_name(&info, prog_fd, prog_name, sizeof(prog_name));
 	if (json_output) {
 		jsonw_start_object(json_wtr);
 		jsonw_uint_field(json_wtr, "id", info.id);
-		if (attach_type < ARRAY_SIZE(attach_type_name))
-			jsonw_string_field(json_wtr, "attach_type",
-					   attach_type_name[attach_type]);
+		if (attach_type_str)
+			jsonw_string_field(json_wtr, "attach_type", attach_type_str);
 		else
 			jsonw_uint_field(json_wtr, "attach_type", attach_type);
 		jsonw_string_field(json_wtr, "attach_flags",
@@ -79,8 +98,8 @@ static int show_bpf_prog(int id, enum bpf_attach_type attach_type,
 		jsonw_end_object(json_wtr);
 	} else {
 		printf("%s%-8u ", level ? "    " : "", info.id);
-		if (attach_type < ARRAY_SIZE(attach_type_name))
-			printf("%-15s", attach_type_name[attach_type]);
+		if (attach_type_str)
+			printf("%-15s", attach_type_str);
 		else
 			printf("type %-10u", attach_type);
 		printf(" %-15s %-15s\n", attach_flags_str, prog_name);

src/common.c

@@ -31,52 +31,6 @@
 #define BPF_FS_MAGIC		0xcafe4a11
 #endif
 
-const char * const attach_type_name[__MAX_BPF_ATTACH_TYPE] = {
-	[BPF_CGROUP_INET_INGRESS]	= "ingress",
-	[BPF_CGROUP_INET_EGRESS]	= "egress",
-	[BPF_CGROUP_INET_SOCK_CREATE]	= "sock_create",
-	[BPF_CGROUP_INET_SOCK_RELEASE]	= "sock_release",
-	[BPF_CGROUP_SOCK_OPS]		= "sock_ops",
-	[BPF_CGROUP_DEVICE]		= "device",
-	[BPF_CGROUP_INET4_BIND]		= "bind4",
-	[BPF_CGROUP_INET6_BIND]		= "bind6",
-	[BPF_CGROUP_INET4_CONNECT]	= "connect4",
-	[BPF_CGROUP_INET6_CONNECT]	= "connect6",
-	[BPF_CGROUP_INET4_POST_BIND]	= "post_bind4",
-	[BPF_CGROUP_INET6_POST_BIND]	= "post_bind6",
-	[BPF_CGROUP_INET4_GETPEERNAME]	= "getpeername4",
-	[BPF_CGROUP_INET6_GETPEERNAME]	= "getpeername6",
-	[BPF_CGROUP_INET4_GETSOCKNAME]	= "getsockname4",
-	[BPF_CGROUP_INET6_GETSOCKNAME]	= "getsockname6",
-	[BPF_CGROUP_UDP4_SENDMSG]	= "sendmsg4",
-	[BPF_CGROUP_UDP6_SENDMSG]	= "sendmsg6",
-	[BPF_CGROUP_SYSCTL]		= "sysctl",
-	[BPF_CGROUP_UDP4_RECVMSG]	= "recvmsg4",
-	[BPF_CGROUP_UDP6_RECVMSG]	= "recvmsg6",
-	[BPF_CGROUP_GETSOCKOPT]		= "getsockopt",
-	[BPF_CGROUP_SETSOCKOPT]		= "setsockopt",
-	[BPF_SK_SKB_STREAM_PARSER]	= "sk_skb_stream_parser",
-	[BPF_SK_SKB_STREAM_VERDICT]	= "sk_skb_stream_verdict",
-	[BPF_SK_SKB_VERDICT]		= "sk_skb_verdict",
-	[BPF_SK_MSG_VERDICT]		= "sk_msg_verdict",
-	[BPF_LIRC_MODE2]		= "lirc_mode2",
-	[BPF_FLOW_DISSECTOR]		= "flow_dissector",
-	[BPF_TRACE_RAW_TP]		= "raw_tp",
-	[BPF_TRACE_FENTRY]		= "fentry",
-	[BPF_TRACE_FEXIT]		= "fexit",
-	[BPF_MODIFY_RETURN]		= "mod_ret",
-	[BPF_LSM_MAC]			= "lsm_mac",
-	[BPF_SK_LOOKUP]			= "sk_lookup",
-	[BPF_TRACE_ITER]		= "trace_iter",
-	[BPF_XDP_DEVMAP]		= "xdp_devmap",
-	[BPF_XDP_CPUMAP]		= "xdp_cpumap",
-	[BPF_XDP]			= "xdp",
-	[BPF_SK_REUSEPORT_SELECT]	= "sk_skb_reuseport_select",
-	[BPF_SK_REUSEPORT_SELECT_OR_MIGRATE]	= "sk_skb_reuseport_select_or_migrate",
-	[BPF_PERF_EVENT]		= "perf_event",
-	[BPF_TRACE_KPROBE_MULTI]	= "trace_kprobe_multi",
-};
-
 void p_err(const char *fmt, ...)
 {
 	va_list ap;
@@ -1009,3 +963,39 @@ bool equal_fn_for_key_as_id(const void *k1, const void *k2, void *ctx)
 {
 	return k1 == k2;
 }
+
+const char *bpf_attach_type_input_str(enum bpf_attach_type t)
+{
+	switch (t) {
+	case BPF_CGROUP_INET_INGRESS:		return "ingress";
+	case BPF_CGROUP_INET_EGRESS:		return "egress";
+	case BPF_CGROUP_INET_SOCK_CREATE:	return "sock_create";
+	case BPF_CGROUP_INET_SOCK_RELEASE:	return "sock_release";
+	case BPF_CGROUP_SOCK_OPS:		return "sock_ops";
+	case BPF_CGROUP_DEVICE:			return "device";
+	case BPF_CGROUP_INET4_BIND:		return "bind4";
+	case BPF_CGROUP_INET6_BIND:		return "bind6";
+	case BPF_CGROUP_INET4_CONNECT:		return "connect4";
+	case BPF_CGROUP_INET6_CONNECT:		return "connect6";
+	case BPF_CGROUP_INET4_POST_BIND:	return "post_bind4";
+	case BPF_CGROUP_INET6_POST_BIND:	return "post_bind6";
+	case BPF_CGROUP_INET4_GETPEERNAME:	return "getpeername4";
+	case BPF_CGROUP_INET6_GETPEERNAME:	return "getpeername6";
+	case BPF_CGROUP_INET4_GETSOCKNAME:	return "getsockname4";
+	case BPF_CGROUP_INET6_GETSOCKNAME:	return "getsockname6";
+	case BPF_CGROUP_UDP4_SENDMSG:		return "sendmsg4";
+	case BPF_CGROUP_UDP6_SENDMSG:		return "sendmsg6";
+	case BPF_CGROUP_SYSCTL:			return "sysctl";
+	case BPF_CGROUP_UDP4_RECVMSG:		return "recvmsg4";
+	case BPF_CGROUP_UDP6_RECVMSG:		return "recvmsg6";
+	case BPF_CGROUP_GETSOCKOPT:		return "getsockopt";
+	case BPF_CGROUP_SETSOCKOPT:		return "setsockopt";
+	case BPF_TRACE_RAW_TP:			return "raw_tp";
+	case BPF_TRACE_FENTRY:			return "fentry";
+	case BPF_TRACE_FEXIT:			return "fexit";
+	case BPF_MODIFY_RETURN:			return "mod_ret";
+	case BPF_SK_REUSEPORT_SELECT:		return "sk_skb_reuseport_select";
+	case BPF_SK_REUSEPORT_SELECT_OR_MIGRATE:	return "sk_skb_reuseport_select_or_migrate";
+	default:	return libbpf_bpf_attach_type_str(t);
+	}
+}

src/link.c

@@ -78,9 +78,11 @@ show_link_header_json(struct bpf_link_info *info, json_writer_t *wtr)
 
 static void show_link_attach_type_json(__u32 attach_type, json_writer_t *wtr)
 {
-	if (attach_type < ARRAY_SIZE(attach_type_name))
-		jsonw_string_field(wtr, "attach_type",
-				   attach_type_name[attach_type]);
+	const char *attach_type_str;
+
+	attach_type_str = libbpf_bpf_attach_type_str(attach_type);
+	if (attach_type_str)
+		jsonw_string_field(wtr, "attach_type", attach_type_str);
 	else
 		jsonw_uint_field(wtr, "attach_type", attach_type);
 }
@@ -196,8 +198,11 @@ static void show_link_header_plain(struct bpf_link_info *info)
 
 static void show_link_attach_type_plain(__u32 attach_type)
 {
-	if (attach_type < ARRAY_SIZE(attach_type_name))
-		printf("attach_type %s  ", attach_type_name[attach_type]);
+	const char *attach_type_str;
+
+	attach_type_str = libbpf_bpf_attach_type_str(attach_type);
+	if (attach_type_str)
+		printf("attach_type %s  ", attach_type_str);
 	else
 		printf("attach_type %u  ", attach_type);
 }

src/main.h

@@ -243,6 +243,20 @@ int print_all_levels(__maybe_unused enum libbpf_print_level level,
 size_t hash_fn_for_key_as_id(const void *key, void *ctx);
 bool equal_fn_for_key_as_id(const void *k1, const void *k2, void *ctx);
 
+/* bpf_attach_type_input_str - convert the provided attach type value into a
+ * textual representation that we accept for input purposes.
+ *
+ * This function is similar in nature to libbpf_bpf_attach_type_str, but
+ * recognizes some attach type names that have been used by the program in the
+ * past and which do not follow the string inference scheme that libbpf uses.
+ * These textual representations should only be used for user input.
+ *
+ * @t: The attach type
+ * Returns a pointer to a static string identifying the attach type. NULL is
+ * returned for unknown bpf_attach_type values.
+ */
+const char *bpf_attach_type_input_str(enum bpf_attach_type t);
+
 static inline void *u32_as_hash_field(__u32 x)
 {
 	return (void *)(uintptr_t)x;

src/prog.c

@@ -41,12 +41,23 @@ enum dump_mode {
 	DUMP_XLATED,
 };
 
+static const bool attach_types[] = {
+	[BPF_SK_SKB_STREAM_PARSER] = true,
+	[BPF_SK_SKB_STREAM_VERDICT] = true,
+	[BPF_SK_SKB_VERDICT] = true,
+	[BPF_SK_MSG_VERDICT] = true,
+	[BPF_FLOW_DISSECTOR] = true,
+	[__MAX_BPF_ATTACH_TYPE] = false,
+};
+
+/* Textual representations traditionally used by the program and kept around
+ * for the sake of backwards compatibility.
+ */
 static const char * const attach_type_strings[] = {
 	[BPF_SK_SKB_STREAM_PARSER] = "stream_parser",
 	[BPF_SK_SKB_STREAM_VERDICT] = "stream_verdict",
 	[BPF_SK_SKB_VERDICT] = "skb_verdict",
 	[BPF_SK_MSG_VERDICT] = "msg_verdict",
-	[BPF_FLOW_DISSECTOR] = "flow_dissector",
 	[__MAX_BPF_ATTACH_TYPE] = NULL,
 };
 
@@ -57,6 +68,14 @@ static 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_types[type]) {
+			const char *attach_type_str;
+
+			attach_type_str = libbpf_bpf_attach_type_str(type);
+			if (!strcmp(str, attach_type_str))
+				return type;
+		}
+
 		if (attach_type_strings[type] &&
 		    is_prefix(str, attach_type_strings[type]))
 			return type;
@@ -2341,8 +2360,8 @@ static int do_help(int argc, char **argv)
 		"                 cgroup/sendmsg6 | cgroup/recvmsg4 | cgroup/recvmsg6 |\n"
 		"                 cgroup/getsockopt | cgroup/setsockopt | cgroup/sock_release |\n"
 		"                 struct_ops | fentry | fexit | freplace | sk_lookup }\n"
-		"       ATTACH_TYPE := { msg_verdict | skb_verdict | stream_verdict |\n"
-		"                        stream_parser | flow_dissector }\n"
+		"       ATTACH_TYPE := { sk_msg_verdict | sk_skb_verdict | sk_skb_stream_verdict |\n"
+		"                        sk_skb_stream_parser | flow_dissector }\n"
 		"       METRIC := { cycles | instructions | l1d_loads | llc_misses | itlb_misses | dtlb_misses }\n"
 		"       " HELP_SPEC_OPTIONS " |\n"
 		"                    {-f|--bpffs} | {-m|--mapcompat} | {-n|--nomount} |\n"