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 <l...@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 | 11 +++++++++++
6 files changed, 21 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..de4644aeb58d 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1614,6 +1614,17 @@ 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;
+#ifdef CONFIG_NET_NS
+ v.val64 = sock_net(sk)->net_cookie;
+#else
+ v.val64 = init_net.net_cookie;
+#endif
+ break;
+
default:
/* We implement the SO_SNDLOWAT etc to not be settable
* (1003.1g 7).
--
2.27.0
