[PATCH bpf 1/4] net: add SO_NETNS_COOKIE socket option
From: Lorenz Bauer <hidden>
Date: 2021-02-10 12:14:04
Also in:
bpf, linux-alpha, linux-api, linux-arch, linux-mips, lkml, sparclinux
Subsystem:
alpha port, bpf [general] (safe dynamic programs and tools), bpf [networking] (tcx & tc bpf, sock_addr), generic include/asm header files, mips, networking [general], networking [sockets], parisc architecture, sparc + ultrasparc (sparc/sparc64), the rest · Maintainers:
Richard Henderson, Matt Turner, Magnus Lindholm, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Arnd Bergmann, Thomas Bogendoerfer, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Kuniyuki Iwashima, Willem de Bruijn, "James E.J. Bottomley", Helge Deller, Andreas Larsson, Linus Torvalds
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. The BPF helpers change slightly: instead of returning 0 when network namespaces are disabled we return the init_net cookie as for the socket option. Cc: linux-api@vger.kernel.org Signed-off-by: Lorenz Bauer <redacted> --- 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/linux/sock_diag.h | 20 ++++++++++++++++++++ include/uapi/asm-generic/socket.h | 2 ++ net/core/filter.c | 9 ++++----- net/core/sock.c | 7 +++++++ 8 files changed, 41 insertions(+), 5 deletions(-)
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/linux/sock_diag.h b/include/linux/sock_diag.h
index 0b9ecd8cf979..6e88436097b1 100644
--- a/include/linux/sock_diag.h
+++ b/include/linux/sock_diag.h@@ -38,6 +38,26 @@ static inline u64 sock_gen_cookie(struct sock *sk) return cookie; } +static inline u64 __sock_gen_netns_cookie(struct sock *sk) +{ +#ifdef CONFIG_NET_NS + return __net_gen_cookie(sk->sk_net.net); +#else + return __net_gen_cookie(&init_net); +#endif +} + +static inline u64 sock_gen_netns_cookie(struct sock *sk) +{ + u64 cookie; + + preempt_disable(); + cookie = __sock_gen_netns_cookie(sk); + preempt_enable(); + + return cookie; +} + int sock_diag_check_cookie(struct sock *sk, const __u32 *cookie); void sock_diag_save_cookie(struct sock *sk, __u32 *cookie);
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/filter.c b/net/core/filter.c
index e15d4741719a..51f47b6913f1 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c@@ -4645,11 +4645,10 @@ static const struct bpf_func_proto bpf_get_socket_cookie_sock_ops_proto = { static u64 __bpf_get_netns_cookie(struct sock *sk) { -#ifdef CONFIG_NET_NS - return __net_gen_cookie(sk ? sk->sk_net.net : &init_net); -#else - return 0; -#endif + if (sk) + return __sock_gen_netns_cookie(sk); + + return __net_gen_cookie(&init_net); } BPF_CALL_1(bpf_get_netns_cookie_sock, struct sock *, ctx)
diff --git a/net/core/sock.c b/net/core/sock.c
index bbcd4b97eddd..2db201c210ca 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c@@ -1606,6 +1606,13 @@ 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_gen_netns_cookie(sk); + break; + default: /* We implement the SO_SNDLOWAT etc to not be settable * (1003.1g 7).
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2.27.0