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From: Lorenz Bauer <lmb@cloudflare.com>
To: eric.dumazet@gmail.com, daniel@iogearbox.net, ast@kernel.org,
	andrii@kernel.org
Cc: bpf@vger.kernel.org, netdev@vger.kernel.org,
	kernel-team@cloudflare.com, Lorenz Bauer <lmb@cloudflare.com>
Subject: [PATCH bpf-next v3 1/4] net: add SO_NETNS_COOKIE socket option
Date: Fri, 19 Feb 2021 15:43:27 +0000	[thread overview]
Message-ID: <20210219154330.93615-2-lmb@cloudflare.com> (raw)
In-Reply-To: <20210219154330.93615-1-lmb@cloudflare.com>

We need to distinguish which network namespace a socket belongs to.
BPF has the useful bpf_get_netns_cookie helper for this, but accessing
it from user space isn't possible. Add a read-only socket option that
returns the netns cookie, similar to SO_COOKIE. If network namespaces
are disabled, SO_NETNS_COOKIE returns the cookie of init_net.

Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
---
 arch/alpha/include/uapi/asm/socket.h  | 2 ++
 arch/mips/include/uapi/asm/socket.h   | 2 ++
 arch/parisc/include/uapi/asm/socket.h | 2 ++
 arch/sparc/include/uapi/asm/socket.h  | 2 ++
 include/uapi/asm-generic/socket.h     | 2 ++
 net/core/sock.c                       | 7 +++++++
 6 files changed, 17 insertions(+)

diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h
index 57420356ce4c..6b3daba60987 100644
--- a/arch/alpha/include/uapi/asm/socket.h
+++ b/arch/alpha/include/uapi/asm/socket.h
@@ -127,6 +127,8 @@
 #define SO_PREFER_BUSY_POLL	69
 #define SO_BUSY_POLL_BUDGET	70
 
+#define SO_NETNS_COOKIE		71
+
 #if !defined(__KERNEL__)
 
 #if __BITS_PER_LONG == 64
diff --git a/arch/mips/include/uapi/asm/socket.h b/arch/mips/include/uapi/asm/socket.h
index 2d949969313b..cdf404a831b2 100644
--- a/arch/mips/include/uapi/asm/socket.h
+++ b/arch/mips/include/uapi/asm/socket.h
@@ -138,6 +138,8 @@
 #define SO_PREFER_BUSY_POLL	69
 #define SO_BUSY_POLL_BUDGET	70
 
+#define SO_NETNS_COOKIE		71
+
 #if !defined(__KERNEL__)
 
 #if __BITS_PER_LONG == 64
diff --git a/arch/parisc/include/uapi/asm/socket.h b/arch/parisc/include/uapi/asm/socket.h
index f60904329bbc..5b5351cdcb33 100644
--- a/arch/parisc/include/uapi/asm/socket.h
+++ b/arch/parisc/include/uapi/asm/socket.h
@@ -119,6 +119,8 @@
 #define SO_PREFER_BUSY_POLL	0x4043
 #define SO_BUSY_POLL_BUDGET	0x4044
 
+#define SO_NETNS_COOKIE		0x4045
+
 #if !defined(__KERNEL__)
 
 #if __BITS_PER_LONG == 64
diff --git a/arch/sparc/include/uapi/asm/socket.h b/arch/sparc/include/uapi/asm/socket.h
index 848a22fbac20..ff79db753dce 100644
--- a/arch/sparc/include/uapi/asm/socket.h
+++ b/arch/sparc/include/uapi/asm/socket.h
@@ -120,6 +120,8 @@
 #define SO_PREFER_BUSY_POLL	 0x0048
 #define SO_BUSY_POLL_BUDGET	 0x0049
 
+#define SO_NETNS_COOKIE		 0x004a
+
 #if !defined(__KERNEL__)
 
 
diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
index 4dcd13d097a9..d588c244ec2f 100644
--- a/include/uapi/asm-generic/socket.h
+++ b/include/uapi/asm-generic/socket.h
@@ -122,6 +122,8 @@
 #define SO_PREFER_BUSY_POLL	69
 #define SO_BUSY_POLL_BUDGET	70
 
+#define SO_NETNS_COOKIE		71
+
 #if !defined(__KERNEL__)
 
 #if __BITS_PER_LONG == 64 || (defined(__x86_64__) && defined(__ILP32__))
diff --git a/net/core/sock.c b/net/core/sock.c
index 0ed98f20448a..84db011a192f 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1614,6 +1614,13 @@ int sock_getsockopt(struct socket *sock, int level, int optname,
 		v.val = sk->sk_bound_dev_if;
 		break;
 
+	case SO_NETNS_COOKIE:
+		lv = sizeof(u64);
+		if (len != lv)
+			return -EINVAL;
+		v.val64 = sock_net(sk)->net_cookie;
+		break;
+
 	default:
 		/* We implement the SO_SNDLOWAT etc to not be settable
 		 * (1003.1g 7).
-- 
2.27.0


  reply	other threads:[~2021-02-19 15:46 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-19 15:43 [PATCH bpf-next v3 0/4] Expose network namespace cookies to user space Lorenz Bauer
2021-02-19 15:43 ` Lorenz Bauer [this message]
2021-02-19 15:43 ` [PATCH bpf-next v3 2/4] nsfs: add an ioctl to discover the network namespace cookie Lorenz Bauer
2021-02-19 15:43 ` [PATCH bpf-next v3 3/4] tools/testing: add test for NS_GET_COOKIE Lorenz Bauer
2021-02-19 15:43 ` [PATCH bpf-next v3 4/4] tools/testing: add a selftest for SO_NETNS_COOKIE Lorenz Bauer
2021-03-12  9:57 ` [PATCH bpf-next v3 0/4] Expose network namespace cookies to user space Tony Lu

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