Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Kuniyuki Iwashima <kuniyu@amazon.co.jp>
To:     "David S . Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Martin KaFai Lau <kafai@fb.com>
CC:     Benjamin Herrenschmidt <benh@amazon.com>,
        Kuniyuki Iwashima <kuniyu@amazon.co.jp>,
        Kuniyuki Iwashima <kuni1840@gmail.com>,
        <osa-contribution-log@amazon.com>, <bpf@vger.kernel.org>,
        <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: [PATCH v1 bpf-next 06/11] bpf: Introduce two attach types for BPF_PROG_TYPE_SK_REUSEPORT.
Date:   Tue, 1 Dec 2020 23:44:13 +0900
Message-ID: <20201201144418.35045-7-kuniyu@amazon.co.jp>
In-Reply-To: <20201201144418.35045-1-kuniyu@amazon.co.jp>
References: <20201201144418.35045-1-kuniyu@amazon.co.jp>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

This commit adds new bpf_attach_type for BPF_PROG_TYPE_SK_REUSEPORT to
check if the attached eBPF program is capable of migrating sockets.

When the eBPF program is attached, the kernel runs it for socket migration
only if the expected_attach_type is BPF_SK_REUSEPORT_SELECT_OR_MIGRATE.
The kernel will change the behaviour depending on the returned value:

  - SK_PASS with selected_sk, select it as a new listener
  - SK_PASS with selected_sk NULL, fall back to the random selection
  - SK_DROP, cancel the migration

Link: https://lore.kernel.org/netdev/20201123003828.xjpjdtk4ygl6tg6h@kafai-mbp.dhcp.thefacebook.com/
Suggested-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
---
 include/uapi/linux/bpf.h       | 2 ++
 kernel/bpf/syscall.c           | 8 ++++++++
 tools/include/uapi/linux/bpf.h | 2 ++
 3 files changed, 12 insertions(+)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 85278deff439..cfc207ae7782 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -241,6 +241,8 @@ enum bpf_attach_type {
 	BPF_XDP_CPUMAP,
 	BPF_SK_LOOKUP,
 	BPF_XDP,
+	BPF_SK_REUSEPORT_SELECT,
+	BPF_SK_REUSEPORT_SELECT_OR_MIGRATE,
 	__MAX_BPF_ATTACH_TYPE
 };
 
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index f3fe9f53f93c..a0796a8de5ea 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2036,6 +2036,14 @@ bpf_prog_load_check_attach(enum bpf_prog_type prog_type,
 		if (expected_attach_type == BPF_SK_LOOKUP)
 			return 0;
 		return -EINVAL;
+	case BPF_PROG_TYPE_SK_REUSEPORT:
+		switch (expected_attach_type) {
+		case BPF_SK_REUSEPORT_SELECT:
+		case BPF_SK_REUSEPORT_SELECT_OR_MIGRATE:
+			return 0;
+		default:
+			return -EINVAL;
+		}
 	case BPF_PROG_TYPE_EXT:
 		if (expected_attach_type)
 			return -EINVAL;
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 85278deff439..cfc207ae7782 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -241,6 +241,8 @@ enum bpf_attach_type {
 	BPF_XDP_CPUMAP,
 	BPF_SK_LOOKUP,
 	BPF_XDP,
+	BPF_SK_REUSEPORT_SELECT,
+	BPF_SK_REUSEPORT_SELECT_OR_MIGRATE,
 	__MAX_BPF_ATTACH_TYPE
 };
 
-- 
2.17.2 (Apple Git-113)