From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>,
Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
Yonghong Song <yhs@fb.com>,
Marek Majkowski <marek@cloudflare.com>,
Lorenz Bauer <lmb@cloudflare.com>,
Alan Maguire <alan.maguire@oracle.com>,
Jesper Dangaard Brouer <brouer@redhat.com>,
David Miller <davem@davemloft.net>,
netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: [PATCH bpf-next v3 2/5] bpf: Add support for setting chain call sequence for programs
Date: Mon, 07 Oct 2019 19:20:37 +0200 [thread overview]
Message-ID: <157046883723.2092443.3902769602513209987.stgit@alrua-x1> (raw)
In-Reply-To: <157046883502.2092443.146052429591277809.stgit@alrua-x1>
From: Toke Høiland-Jørgensen <toke@redhat.com>
This adds support for setting and deleting bpf chain call programs through
a couple of new commands in the bpf() syscall. The CHAIN_ADD and CHAIN_DEL
commands take two eBPF program fds and a return code, and install the
'next' program to be chain called after the 'prev' program if that program
returns 'retcode'. A retcode of -1 means "wildcard", so that the program
will be executed regardless of the previous program's return code.
The syscall command names are based on Alexei's prog_chain example[0],
which Alan helpfully rebased on current bpf-next. However, the logic and
program storage is obviously adapted to the execution logic in the previous
commit.
[0] https://git.kernel.org/pub/scm/linux/kernel/git/ast/bpf.git/commit/?h=prog_chain&id=f54f45d00f91e083f6aec2abe35b6f0be52ae85b&context=15
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
---
include/uapi/linux/bpf.h | 10 ++++++
kernel/bpf/syscall.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 88 insertions(+)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 1ce80a227be3..b03c23963af8 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -107,6 +107,9 @@ enum bpf_cmd {
BPF_MAP_LOOKUP_AND_DELETE_ELEM,
BPF_MAP_FREEZE,
BPF_BTF_GET_NEXT_ID,
+ BPF_PROG_CHAIN_ADD,
+ BPF_PROG_CHAIN_DEL,
+ BPF_PROG_CHAIN_GET,
};
enum bpf_map_type {
@@ -516,6 +519,13 @@ union bpf_attr {
__u64 probe_offset; /* output: probe_offset */
__u64 probe_addr; /* output: probe_addr */
} task_fd_query;
+
+ struct { /* anonymous struct used by BPF_PROG_CHAIN_* commands */
+ __u32 prev_prog_fd;
+ __u32 next_prog_fd;
+ __u32 retcode;
+ __u32 next_prog_id; /* output: prog_id */
+ };
} __attribute__((aligned(8)));
/* The description below is an attempt at providing documentation to eBPF
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index b8a203a05881..be8112e08a88 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2113,6 +2113,79 @@ static int bpf_prog_test_run(const union bpf_attr *attr,
return ret;
}
+#define BPF_PROG_CHAIN_LAST_FIELD next_prog_id
+
+static int bpf_prog_chain(int cmd, const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ struct bpf_prog *prog, *next_prog, *old_prog;
+ struct bpf_prog **array;
+ int ret = -EOPNOTSUPP;
+ u32 index, prog_id;
+
+ if (CHECK_ATTR(BPF_PROG_CHAIN))
+ return -EINVAL;
+
+ /* Index 0 is wildcard, encoded as ~0 by userspace */
+ if (attr->retcode == ((u32) ~0))
+ index = 0;
+ else
+ index = attr->retcode + 1;
+
+ if (index >= BPF_NUM_CHAIN_SLOTS)
+ return -E2BIG;
+
+ prog = bpf_prog_get(attr->prev_prog_fd);
+ if (IS_ERR(prog))
+ return PTR_ERR(prog);
+
+ /* If the chain_calls bit is not set, that's because the chain call flag
+ * was not set on program load, and so we can't support chain calls.
+ */
+ if (!prog->chain_calls)
+ goto out;
+
+ array = prog->aux->chain_progs;
+
+ switch (cmd) {
+ case BPF_PROG_CHAIN_ADD:
+ next_prog = bpf_prog_get(attr->next_prog_fd);
+ if (IS_ERR(next_prog)) {
+ ret = PTR_ERR(next_prog);
+ break;
+ }
+ old_prog = xchg(array + index, next_prog);
+ if (old_prog)
+ bpf_prog_put(old_prog);
+ ret = 0;
+ break;
+ case BPF_PROG_CHAIN_DEL:
+ old_prog = xchg(array + index, NULL);
+ if (old_prog) {
+ bpf_prog_put(old_prog);
+ ret = 0;
+ } else {
+ ret = -ENOENT;
+ }
+ break;
+ case BPF_PROG_CHAIN_GET:
+ old_prog = READ_ONCE(array[index]);
+ if (old_prog) {
+ prog_id = old_prog->aux->id;
+ if (put_user(prog_id, &uattr->next_prog_id))
+ ret = -EFAULT;
+ else
+ ret = 0;
+ } else
+ ret = -ENOENT;
+ break;
+ }
+
+out:
+ bpf_prog_put(prog);
+ return ret;
+}
+
#define BPF_OBJ_GET_NEXT_ID_LAST_FIELD next_id
static int bpf_obj_get_next_id(const union bpf_attr *attr,
@@ -2885,6 +2958,11 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz
case BPF_PROG_TEST_RUN:
err = bpf_prog_test_run(&attr, uattr);
break;
+ case BPF_PROG_CHAIN_ADD:
+ case BPF_PROG_CHAIN_DEL:
+ case BPF_PROG_CHAIN_GET:
+ err = bpf_prog_chain(cmd, &attr, uattr);
+ break;
case BPF_PROG_GET_NEXT_ID:
err = bpf_obj_get_next_id(&attr, uattr,
&prog_idr, &prog_idr_lock);
next prev parent reply other threads:[~2019-10-07 17:20 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-07 17:20 [PATCH bpf-next v3 0/5] xdp: Support multiple programs on a single interface through chain calls Toke Høiland-Jørgensen
2019-10-07 17:20 ` [PATCH bpf-next v3 1/5] bpf: Support chain calling multiple BPF programs after each other Toke Høiland-Jørgensen
2019-10-07 20:42 ` Alexei Starovoitov
2019-10-08 8:07 ` Toke Høiland-Jørgensen
2019-10-09 1:51 ` Alexei Starovoitov
2019-10-09 8:03 ` Toke Høiland-Jørgensen
2019-10-10 4:41 ` Alexei Starovoitov
2019-10-14 12:35 ` Toke Høiland-Jørgensen
2019-10-14 17:08 ` John Fastabend
2019-10-14 18:48 ` Toke Høiland-Jørgensen
2019-10-15 16:30 ` Edward Cree
2019-10-15 16:42 ` Toke Høiland-Jørgensen
2019-10-15 18:33 ` Edward Cree
2019-10-17 12:11 ` Toke Høiland-Jørgensen
2019-10-22 17:27 ` Edward Cree
2019-10-22 18:07 ` Toke Høiland-Jørgensen
2019-11-12 2:51 ` static and dynamic linking. Was: [PATCH bpf-next v3 1/5] bpf: Support chain calling multiple BPF Alexei Starovoitov
2019-11-12 16:20 ` Toke Høiland-Jørgensen
2019-11-12 19:52 ` Alexei Starovoitov
2019-11-12 21:25 ` Edward Cree
2019-11-12 23:18 ` Alexei Starovoitov
2019-11-13 18:30 ` Edward Cree
2019-11-13 18:51 ` Andrii Nakryiko
2019-11-15 2:13 ` Alexei Starovoitov
2019-11-15 16:56 ` John Fastabend
2019-11-12 23:25 ` John Fastabend
2019-11-13 0:21 ` Alexei Starovoitov
2019-11-13 5:33 ` John Fastabend
2019-11-15 1:50 ` Alexei Starovoitov
2019-11-15 16:39 ` John Fastabend
2019-11-14 15:41 ` Toke Høiland-Jørgensen
2019-11-12 16:32 ` Edward Cree
2019-11-15 11:48 ` Lorenz Bauer
2019-11-15 23:02 ` Alexei Starovoitov
2019-11-18 13:29 ` Lorenz Bauer
2019-10-21 23:51 ` [PATCH bpf-next v3 1/5] bpf: Support chain calling multiple BPF programs after each other Edward Cree
2019-10-16 2:28 ` Alexei Starovoitov
2019-10-16 8:27 ` Jesper Dangaard Brouer
2019-10-16 10:35 ` Daniel Borkmann
2019-10-16 11:16 ` Toke Høiland-Jørgensen
2019-10-16 13:51 ` Toke Høiland-Jørgensen
2019-10-19 20:09 ` bpf indirect calls Alexei Starovoitov
2019-10-20 10:58 ` Toke Høiland-Jørgensen
2019-10-25 16:30 ` Alexei Starovoitov
2019-10-27 12:15 ` Toke Høiland-Jørgensen
2023-09-27 13:27 ` Matt Bobrowski
2023-09-29 21:06 ` Alexei Starovoitov
2023-10-02 18:50 ` Barret Rhoden
2023-10-06 9:36 ` Matt Bobrowski
2023-10-06 18:49 ` Alexei Starovoitov
2023-10-19 12:28 ` Matt Bobrowski
2019-10-09 10:19 ` [PATCH bpf-next v3 1/5] bpf: Support chain calling multiple BPF programs after each other Jesper Dangaard Brouer
2019-10-09 17:57 ` Alexei Starovoitov
2019-10-07 17:20 ` Toke Høiland-Jørgensen [this message]
2019-10-07 20:38 ` [PATCH bpf-next v3 2/5] bpf: Add support for setting chain call sequence for programs Daniel Borkmann
2019-10-08 8:09 ` Toke Høiland-Jørgensen
2019-10-07 17:20 ` [PATCH bpf-next v3 3/5] tools: Update bpf.h header for program chain calls Toke Høiland-Jørgensen
2019-10-07 17:20 ` [PATCH bpf-next v3 4/5] libbpf: Add syscall wrappers for BPF_PROG_CHAIN_* commands Toke Høiland-Jørgensen
2019-10-07 17:20 ` [PATCH bpf-next v3 5/5] selftests: Add tests for XDP chain calls Toke Høiland-Jørgensen
2019-10-07 18:58 ` [PATCH bpf-next v3 0/5] xdp: Support multiple programs on a single interface through " John Fastabend
2019-10-08 8:42 ` Toke Høiland-Jørgensen
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