[PATCH] bpf: bpftool, add support for attaching programs to maps

[John Fastabend <john.fastabend@gmail.com>]

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>
---
 tools/bpf/bpftool/main.h |    1 +
 tools/bpf/bpftool/prog.c |   92 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 92 insertions(+), 1 deletion(-)

diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index 40492cd..9ceb2b6 100644
--- a/tools/bpf/bpftool/main.h
+++ b/tools/bpf/bpftool/main.h
@@ -137,6 +137,7 @@ int cmd_select(const struct cmd *cmds, int argc, char **argv,
 int do_cgroup(int argc, char **arg);
 int do_perf(int argc, char **arg);
 int do_net(int argc, char **arg);
+int do_attach_cmd(int argc, char **arg);
 
 int prog_parse_fd(int *argc, char ***argv);
 int map_parse_fd(int *argc, char ***argv);
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index b1cd3bc..280881d 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -77,6 +77,26 @@
 	[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 +717,71 @@ 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(4)) {
+		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;
+	}
+	return 0;
+}
+
+static int do_detach(int argc, char **argv)
+{
+	enum bpf_attach_type attach_type;
+	int err, mapfd, progfd;
+
+	if (!REQ_ARGS(4)) {
+		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;
+	}
+	return 0;
+}
 static int do_load(int argc, char **argv)
 {
 	enum bpf_attach_type expected_attach_type;
@@ -942,6 +1027,7 @@ 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 help\n"
 		"\n"
 		"       " HELP_SPEC_MAP "\n"
@@ -953,10 +1039,12 @@ 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]);
 
 	return 0;
 }
@@ -968,6 +1056,8 @@ static int do_help(int argc, char **argv)
 	{ "dump",	do_dump },
 	{ "pin",	do_pin },
 	{ "load",	do_load },
+	{ "attach",	do_attach },
+	{ "detach",	do_detach },
 	{ 0 }
 };