bpftool: support loading flow dissector

This commit adds support for loading/attaching/detaching flow
dissector program.

When `bpftool loadall` is called with a flow_dissector prog (i.e. when the
'type flow_dissector' argument is passed), we load and pin all programs.
User is responsible to construct the jump table for the tail calls.

The last argument of `bpftool attach` is made optional for this use
case.

Example:
bpftool prog load tools/testing/selftests/bpf/bpf_flow.o \
        /sys/fs/bpf/flow type flow_dissector \
	pinmaps /sys/fs/bpf/flow

bpftool map update pinned /sys/fs/bpf/flow/jmp_table \
        key 0 0 0 0 \
        value pinned /sys/fs/bpf/flow/IP

bpftool map update pinned /sys/fs/bpf/flow/jmp_table \
        key 1 0 0 0 \
        value pinned /sys/fs/bpf/flow/IPV6

bpftool map update pinned /sys/fs/bpf/flow/jmp_table \
        key 2 0 0 0 \
        value pinned /sys/fs/bpf/flow/IPV6OP

bpftool map update pinned /sys/fs/bpf/flow/jmp_table \
        key 3 0 0 0 \
        value pinned /sys/fs/bpf/flow/IPV6FR

bpftool map update pinned /sys/fs/bpf/flow/jmp_table \
        key 4 0 0 0 \
        value pinned /sys/fs/bpf/flow/MPLS

bpftool map update pinned /sys/fs/bpf/flow/jmp_table \
        key 5 0 0 0 \
        value pinned /sys/fs/bpf/flow/VLAN

bpftool prog attach pinned /sys/fs/bpf/flow/flow_dissector flow_dissector

Tested by using the above lines to load the prog in
the test_flow_dissector.sh selftest.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 46 insertions, 39 deletions

diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index c2ce4220bbca..5ff5544596e7 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -81,6 +81,7 @@ 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",
+        [BPF_FLOW_DISSECTOR] = "flow_dissector",
         [__MAX_BPF_ATTACH_TYPE] = NULL,
 };
 
@@ -721,30 +722,49 @@ int map_replace_compar(const void *p1, const void *p2)
         return a->idx - b->idx;
 }
 
-static int do_attach(int argc, char **argv)
+static int parse_attach_detach_args(int argc, char **argv, int *progfd,
+                                    enum bpf_attach_type *attach_type,
+                                    int *mapfd)
 {
-        enum bpf_attach_type attach_type;
-        int err, mapfd, progfd;
-
-        if (!REQ_ARGS(5)) {
-                p_err("too few parameters for map attach");
+        if (!REQ_ARGS(3))
                 return -EINVAL;
-        }
 
-        progfd = prog_parse_fd(&argc, &argv);
-        if (progfd < 0)
-                return progfd;
+        *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");
+        *attach_type = parse_attach_type(*argv);
+        if (*attach_type == __MAX_BPF_ATTACH_TYPE) {
+                p_err("invalid attach/detach type");
                 return -EINVAL;
         }
+
+        if (*attach_type == BPF_FLOW_DISSECTOR) {
+                *mapfd = -1;
+                return 0;
+        }
+
         NEXT_ARG();
+        if (!REQ_ARGS(2))
+                return -EINVAL;
+
+        *mapfd = map_parse_fd(&argc, &argv);
+        if (*mapfd < 0)
+                return *mapfd;
+
+        return 0;
+}
 
-        mapfd = map_parse_fd(&argc, &argv);
-        if (mapfd < 0)
-                return mapfd;
+static int do_attach(int argc, char **argv)
+{
+        enum bpf_attach_type attach_type;
+        int err, progfd;
+        int mapfd;
+
+        err = parse_attach_detach_args(argc, argv,
+                                       &progfd, &attach_type, &mapfd);
+        if (err)
+                return err;
 
         err = bpf_prog_attach(progfd, mapfd, attach_type, 0);
         if (err) {
@@ -760,27 +780,13 @@ static int do_attach(int argc, char **argv)
 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;
+        int err, progfd;
+        int mapfd;
 
-        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 = parse_attach_detach_args(argc, argv,
+                                       &progfd, &attach_type, &mapfd);
+        if (err)
+                return err;
 
         err = bpf_prog_detach2(progfd, mapfd, attach_type);
         if (err) {
@@ -1094,8 +1100,8 @@ static int do_help(int argc, char **argv)
                 "                         [type TYPE] [dev NAME] \\\n"
                 "                         [map { idx IDX | name NAME } MAP]\\\n"
                 "                         [pinmaps MAP_DIR]\n"
-                "       %s %s attach PROG ATTACH_TYPE MAP\n"
-                "       %s %s detach PROG ATTACH_TYPE 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"
@@ -1107,7 +1113,8 @@ 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"
+                "       ATTACH_TYPE := { msg_verdict | skb_verdict | skb_parse |\n"
+                "                        flow_dissector }\n"
                 "       " HELP_SPEC_OPTIONS "\n"
                 "",
                 bin_name, argv[-2], bin_name, argv[-2], bin_name, argv[-2],