[PATCH] net: introduce SO_BPF_EXTENSIONS

[PATCH] net: introduce SO_BPF_EXTENSIONS

[Michal Sekletar]

userspace packet capturing libraries (e.g. libpcap) don't have a way how to find
out which BPF extensions are supported by the kernel, except compiling a filter
which uses extensions and trying to apply filter to the socket. This is very
inconvenient.

Therefore this commit introduces new option which can be used as an argument for
getsockopt() and allows one to obtain information about which BPF extensions are
supported by the kernel.

Signed-off-by: Michal Sekletar <msekleta@redhat.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Daniel Borkmann <dborkman@redhat.com>
---
 arch/alpha/include/uapi/asm/socket.h   |  2 ++
 arch/avr32/include/uapi/asm/socket.h   |  2 ++
 arch/cris/include/uapi/asm/socket.h    |  2 ++
 arch/frv/include/uapi/asm/socket.h     |  2 ++
 arch/ia64/include/uapi/asm/socket.h    |  2 ++
 arch/m32r/include/uapi/asm/socket.h    |  2 ++
 arch/mips/include/uapi/asm/socket.h    |  2 ++
 arch/mn10300/include/uapi/asm/socket.h |  2 ++
 arch/parisc/include/uapi/asm/socket.h  |  2 ++
 arch/powerpc/include/uapi/asm/socket.h |  2 ++
 arch/s390/include/uapi/asm/socket.h    |  2 ++
 arch/sparc/include/uapi/asm/socket.h   |  2 ++
 arch/xtensa/include/uapi/asm/socket.h  |  2 ++
 include/linux/filter.h                 | 18 ++++++++++++++++++
 include/net/sock.h                     | 19 +++++++++++++++++++
 include/uapi/asm-generic/socket.h      |  2 ++
 net/core/sock.c                        |  4 ++++
 17 files changed, 69 insertions(+)

diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h
index e3a1491..3de1394 100644
--- a/arch/alpha/include/uapi/asm/socket.h
+++ b/arch/alpha/include/uapi/asm/socket.h
@@ -85,4 +85,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _UAPI_ASM_SOCKET_H */
diff --git a/arch/avr32/include/uapi/asm/socket.h b/arch/avr32/include/uapi/asm/socket.h
index 4399364..35e677e 100644
--- a/arch/avr32/include/uapi/asm/socket.h
+++ b/arch/avr32/include/uapi/asm/socket.h
@@ -78,4 +78,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* __ASM_AVR32_SOCKET_H */
diff --git a/arch/cris/include/uapi/asm/socket.h b/arch/cris/include/uapi/asm/socket.h
index 13829aa..ed94e5e 100644
--- a/arch/cris/include/uapi/asm/socket.h
+++ b/arch/cris/include/uapi/asm/socket.h
@@ -80,6 +80,8 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _ASM_SOCKET_H */
 
 
diff --git a/arch/frv/include/uapi/asm/socket.h b/arch/frv/include/uapi/asm/socket.h
index 5d42997..ca2c6e6 100644
--- a/arch/frv/include/uapi/asm/socket.h
+++ b/arch/frv/include/uapi/asm/socket.h
@@ -78,5 +78,7 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _ASM_SOCKET_H */
 
diff --git a/arch/ia64/include/uapi/asm/socket.h b/arch/ia64/include/uapi/asm/socket.h
index c25302f..a1b49ba 100644
--- a/arch/ia64/include/uapi/asm/socket.h
+++ b/arch/ia64/include/uapi/asm/socket.h
@@ -87,4 +87,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _ASM_IA64_SOCKET_H */
diff --git a/arch/m32r/include/uapi/asm/socket.h b/arch/m32r/include/uapi/asm/socket.h
index 5296665..6c9a24b 100644
--- a/arch/m32r/include/uapi/asm/socket.h
+++ b/arch/m32r/include/uapi/asm/socket.h
@@ -78,4 +78,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _ASM_M32R_SOCKET_H */
diff --git a/arch/mips/include/uapi/asm/socket.h b/arch/mips/include/uapi/asm/socket.h
index 0df9787..a14baa2 100644
--- a/arch/mips/include/uapi/asm/socket.h
+++ b/arch/mips/include/uapi/asm/socket.h
@@ -96,4 +96,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _UAPI_ASM_SOCKET_H */
diff --git a/arch/mn10300/include/uapi/asm/socket.h b/arch/mn10300/include/uapi/asm/socket.h
index 71dedca..6aa3ce1 100644
--- a/arch/mn10300/include/uapi/asm/socket.h
+++ b/arch/mn10300/include/uapi/asm/socket.h
@@ -78,4 +78,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/parisc/include/uapi/asm/socket.h b/arch/parisc/include/uapi/asm/socket.h
index 7c614d0..e789b32 100644
--- a/arch/parisc/include/uapi/asm/socket.h
+++ b/arch/parisc/include/uapi/asm/socket.h
@@ -77,6 +77,8 @@
 
 #define SO_MAX_PACING_RATE	0x4048
 
+#define SO_BPF_EXTENSIONS	0x4029
+
 /* O_NONBLOCK clashes with the bits used for socket types.  Therefore we
  * have to define SOCK_NONBLOCK to a different value here.
  */
diff --git a/arch/powerpc/include/uapi/asm/socket.h b/arch/powerpc/include/uapi/asm/socket.h
index fa69832..a9c3e2e 100644
--- a/arch/powerpc/include/uapi/asm/socket.h
+++ b/arch/powerpc/include/uapi/asm/socket.h
@@ -85,4 +85,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif	/* _ASM_POWERPC_SOCKET_H */
diff --git a/arch/s390/include/uapi/asm/socket.h b/arch/s390/include/uapi/asm/socket.h
index c286c2e..e031332 100644
--- a/arch/s390/include/uapi/asm/socket.h
+++ b/arch/s390/include/uapi/asm/socket.h
@@ -84,4 +84,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/sparc/include/uapi/asm/socket.h b/arch/sparc/include/uapi/asm/socket.h
index 0f21e9a..54d9608 100644
--- a/arch/sparc/include/uapi/asm/socket.h
+++ b/arch/sparc/include/uapi/asm/socket.h
@@ -74,6 +74,8 @@
 
 #define SO_MAX_PACING_RATE	0x0031
 
+#define SO_BPF_EXTENSIONS	0x0032
+
 /* Security levels - as per NRL IPv6 - don't actually do anything */
 #define SO_SECURITY_AUTHENTICATION		0x5001
 #define SO_SECURITY_ENCRYPTION_TRANSPORT	0x5002
diff --git a/arch/xtensa/include/uapi/asm/socket.h b/arch/xtensa/include/uapi/asm/socket.h
index 7db5c22..39acec0 100644
--- a/arch/xtensa/include/uapi/asm/socket.h
+++ b/arch/xtensa/include/uapi/asm/socket.h
@@ -89,4 +89,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif	/* _XTENSA_SOCKET_H */
diff --git a/include/linux/filter.h b/include/linux/filter.h
index ff4e40c..9f0ea23 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -151,4 +151,22 @@ enum {
 	BPF_S_ANC_PAY_OFFSET,
 };
 
+enum {
+	BPF_ANC_FLAG_PROTOCOL         = (1 << 0),
+	BPF_ANC_FLAG_PKTTYPE          =	(1 << 1),
+	BPF_ANC_FLAG_IFINDEX          = (1 << 2),
+	BPF_ANC_FLAG_NLATTR           = (1 << 3),
+	BPF_ANC_FLAG_NLATTR_NEST      = (1 << 4),
+	BPF_ANC_FLAG_MARK             = (1 << 5),
+	BPF_ANC_FLAG_QUEUE            = (1 << 6),
+	BPF_ANC_FLAG_HATYPE           = (1 << 7),
+	BPF_ANC_FLAG_RXHASH           = (1 << 8),
+	BPF_ANC_FLAG_CPU              = (1 << 9),
+	BPF_ANC_FLAG_ALU_XOR_X        = (1 << 10),
+	BPF_ANC_FLAG_SECCOMP_LD_W     = (1 << 11),
+	BPF_ANC_FLAG_VLAN_TAG         = (1 << 12),
+	BPF_ANC_FLAG_VLAN_TAG_PRESENT = (1 << 13),
+	BPF_ANC_FLAG_PAY_OFFSET       = (1 << 14),
+};
+
 #endif /* __LINUX_FILTER_H__ */
diff --git a/include/net/sock.h b/include/net/sock.h
index e3a18ff..b0a1887 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2282,4 +2282,23 @@ extern int sysctl_optmem_max;
 extern __u32 sysctl_wmem_default;
 extern __u32 sysctl_rmem_default;
 
+static inline int bpf_get_extensions(void)
+{
+	return BPF_ANC_FLAG_PROTOCOL |
+		BPF_ANC_FLAG_PKTTYPE |
+		BPF_ANC_FLAG_IFINDEX |
+		BPF_ANC_FLAG_NLATTR |
+		BPF_ANC_FLAG_NLATTR_NEST |
+		BPF_ANC_FLAG_MARK |
+		BPF_ANC_FLAG_QUEUE |
+		BPF_ANC_FLAG_HATYPE |
+		BPF_ANC_FLAG_RXHASH |
+		BPF_ANC_FLAG_CPU |
+		BPF_ANC_FLAG_ALU_XOR_X |
+		BPF_ANC_FLAG_SECCOMP_LD_W |
+		BPF_ANC_FLAG_VLAN_TAG |
+		BPF_ANC_FLAG_VLAN_TAG_PRESENT |
+		BPF_ANC_FLAG_PAY_OFFSET;
+}
+
 #endif	/* _SOCK_H */
diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
index 38f14d0..ea0796b 100644
--- a/include/uapi/asm-generic/socket.h
+++ b/include/uapi/asm-generic/socket.h
@@ -80,4 +80,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* __ASM_GENERIC_SOCKET_H */
diff --git a/net/core/sock.c b/net/core/sock.c
index ab20ed9..2acec15 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1168,6 +1168,10 @@ int sock_getsockopt(struct socket *sock, int level, int optname,
 		v.val = sock_flag(sk, SOCK_FILTER_LOCKED);
 		break;
 
+	case SO_BPF_EXTENSIONS:
+		v.val = bpf_get_extensions();
+		break;
+
 	case SO_SELECT_ERR_QUEUE:
 		v.val = sock_flag(sk, SOCK_SELECT_ERR_QUEUE);
 		break;
-- 
1.8.3.1

Re: [PATCH] net: introduce SO_BPF_EXTENSIONS

[Eric Dumazet]

On Thu, 2013-11-28 at 12:57 +0100, Michal Sekletar wrote:

> +enum {
> +	BPF_ANC_FLAG_PROTOCOL         = (1 << 0),
> +	BPF_ANC_FLAG_PKTTYPE          =	(1 << 1),
> +	BPF_ANC_FLAG_IFINDEX          = (1 << 2),
> +	BPF_ANC_FLAG_NLATTR           = (1 << 3),
> +	BPF_ANC_FLAG_NLATTR_NEST      = (1 << 4),
> +	BPF_ANC_FLAG_MARK             = (1 << 5),
> +	BPF_ANC_FLAG_QUEUE            = (1 << 6),
> +	BPF_ANC_FLAG_HATYPE           = (1 << 7),
> +	BPF_ANC_FLAG_RXHASH           = (1 << 8),
> +	BPF_ANC_FLAG_CPU              = (1 << 9),
> +	BPF_ANC_FLAG_ALU_XOR_X        = (1 << 10),
> +	BPF_ANC_FLAG_SECCOMP_LD_W     = (1 << 11),
> +	BPF_ANC_FLAG_VLAN_TAG         = (1 << 12),
> +	BPF_ANC_FLAG_VLAN_TAG_PRESENT = (1 << 13),
> +	BPF_ANC_FLAG_PAY_OFFSET       = (1 << 14),
> +};
> +

Why spending 15 bits (out of 32), for all these extensions ?

It seems a single one should be enough.

I do not think we will ever remove one of these extension.

Re: [PATCH] net: introduce SO_BPF_EXTENSIONS

[Daniel Borkmann]

On 11/28/2013 06:31 PM, Eric Dumazet wrote:
> On Thu, 2013-11-28 at 12:57 +0100, Michal Sekletar wrote:
>
>> +enum {
>> +	BPF_ANC_FLAG_PROTOCOL         = (1 << 0),
>> +	BPF_ANC_FLAG_PKTTYPE          =	(1 << 1),
>> +	BPF_ANC_FLAG_IFINDEX          = (1 << 2),
>> +	BPF_ANC_FLAG_NLATTR           = (1 << 3),
>> +	BPF_ANC_FLAG_NLATTR_NEST      = (1 << 4),
>> +	BPF_ANC_FLAG_MARK             = (1 << 5),
>> +	BPF_ANC_FLAG_QUEUE            = (1 << 6),
>> +	BPF_ANC_FLAG_HATYPE           = (1 << 7),
>> +	BPF_ANC_FLAG_RXHASH           = (1 << 8),
>> +	BPF_ANC_FLAG_CPU              = (1 << 9),
>> +	BPF_ANC_FLAG_ALU_XOR_X        = (1 << 10),
>> +	BPF_ANC_FLAG_SECCOMP_LD_W     = (1 << 11),
>> +	BPF_ANC_FLAG_VLAN_TAG         = (1 << 12),
>> +	BPF_ANC_FLAG_VLAN_TAG_PRESENT = (1 << 13),
>> +	BPF_ANC_FLAG_PAY_OFFSET       = (1 << 14),
>> +};
>> +
>
> Why spending 15 bits (out of 32), for all these extensions ?
>
> It seems a single one should be enough.
>
> I do not think we will ever remove one of these extension.

Agreed, this will just cripple of us adding other extensions in
terms of uapi. I assume there won't be so much more extensions,
but it's of course hard to predict the future. ;-)

Re: [PATCH] net: introduce SO_BPF_EXTENSIONS

[Michal Sekletár]

On Fri, Nov 29, 2013 at 3:13 PM, Daniel Borkmann <dborkman@redhat.com> wrote:
> On 11/28/2013 06:31 PM, Eric Dumazet wrote:
>>
>> On Thu, 2013-11-28 at 12:57 +0100, Michal Sekletar wrote:
>>
>>> +enum {
>>> +       BPF_ANC_FLAG_PROTOCOL         = (1 << 0),
>>> +       BPF_ANC_FLAG_PKTTYPE          = (1 << 1),
>>> +       BPF_ANC_FLAG_IFINDEX          = (1 << 2),
>>> +       BPF_ANC_FLAG_NLATTR           = (1 << 3),
>>> +       BPF_ANC_FLAG_NLATTR_NEST      = (1 << 4),
>>> +       BPF_ANC_FLAG_MARK             = (1 << 5),
>>> +       BPF_ANC_FLAG_QUEUE            = (1 << 6),
>>> +       BPF_ANC_FLAG_HATYPE           = (1 << 7),
>>> +       BPF_ANC_FLAG_RXHASH           = (1 << 8),
>>> +       BPF_ANC_FLAG_CPU              = (1 << 9),
>>> +       BPF_ANC_FLAG_ALU_XOR_X        = (1 << 10),
>>> +       BPF_ANC_FLAG_SECCOMP_LD_W     = (1 << 11),
>>> +       BPF_ANC_FLAG_VLAN_TAG         = (1 << 12),
>>> +       BPF_ANC_FLAG_VLAN_TAG_PRESENT = (1 << 13),
>>> +       BPF_ANC_FLAG_PAY_OFFSET       = (1 << 14),
>>> +};
>>> +
>>
>>
>> Why spending 15 bits (out of 32), for all these extensions ?
>>
>> It seems a single one should be enough.
>>
>> I do not think we will ever remove one of these extension.
>
>
> Agreed, this will just cripple of us adding other extensions in
> terms of uapi. I assume there won't be so much more extensions,
> but it's of course hard to predict the future. ;-)
>

Not sure I follow. Can you please elaborate on the explanation. Please
bare with me this is my first kernel patch submission.

Thanks,

Michal

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Re: [PATCH] net: introduce SO_BPF_EXTENSIONS

[Eric Dumazet]

On Thu, 2013-12-05 at 18:28 +0100, Michal Sekletár wrote:
> On Fri, Nov 29, 2013 at 3:13 PM, Daniel Borkmann <dborkman@redhat.com> wrote:
> > On 11/28/2013 06:31 PM, Eric Dumazet wrote:
> >>
> >> On Thu, 2013-11-28 at 12:57 +0100, Michal Sekletar wrote:
> >>
> >>> +enum {
> >>> +       BPF_ANC_FLAG_PROTOCOL         = (1 << 0),
> >>> +       BPF_ANC_FLAG_PKTTYPE          = (1 << 1),
> >>> +       BPF_ANC_FLAG_IFINDEX          = (1 << 2),
> >>> +       BPF_ANC_FLAG_NLATTR           = (1 << 3),
> >>> +       BPF_ANC_FLAG_NLATTR_NEST      = (1 << 4),
> >>> +       BPF_ANC_FLAG_MARK             = (1 << 5),
> >>> +       BPF_ANC_FLAG_QUEUE            = (1 << 6),
> >>> +       BPF_ANC_FLAG_HATYPE           = (1 << 7),
> >>> +       BPF_ANC_FLAG_RXHASH           = (1 << 8),
> >>> +       BPF_ANC_FLAG_CPU              = (1 << 9),
> >>> +       BPF_ANC_FLAG_ALU_XOR_X        = (1 << 10),
> >>> +       BPF_ANC_FLAG_SECCOMP_LD_W     = (1 << 11),
> >>> +       BPF_ANC_FLAG_VLAN_TAG         = (1 << 12),
> >>> +       BPF_ANC_FLAG_VLAN_TAG_PRESENT = (1 << 13),
> >>> +       BPF_ANC_FLAG_PAY_OFFSET       = (1 << 14),
> >>> +};
> >>> +
> >>
> >>
> >> Why spending 15 bits (out of 32), for all these extensions ?
> >>
> >> It seems a single one should be enough.
> >>
> >> I do not think we will ever remove one of these extension.
> >
> >
> > Agreed, this will just cripple of us adding other extensions in
> > terms of uapi. I assume there won't be so much more extensions,
> > but it's of course hard to predict the future. ;-)
> >
> 
> Not sure I follow. Can you please elaborate on the explanation. Please
> bare with me this is my first kernel patch submission.

if SO_BPF_EXTENSIONS is supported, than you can assume that all current
extensions are supported.

No need to consume one bit per feature, as all these features wont ever
disappear from linux.

RE: [PATCH] net: introduce SO_BPF_EXTENSIONS

[David Laight]

> if SO_BPF_EXTENSIONS is supported, than you can assume that all current
> extensions are supported.
> 
> No need to consume one bit per feature, as all these features wont ever
> disappear from linux.

However one of the BSDs could add a subset of the features and
wish to advertise the fact.
So using extra flags for non-trivial extensions could be useful.

	David

Re: [PATCH] net: introduce SO_BPF_EXTENSIONS

[Daniel Borkmann]

On 12/06/2013 10:50 AM, David Laight wrote:
>> if SO_BPF_EXTENSIONS is supported, than you can assume that all current
>> extensions are supported.
>>
>> No need to consume one bit per feature, as all these features wont ever
>> disappear from linux.
>
> However one of the BSDs could add a subset of the features and
> wish to advertise the fact.
> So using extra flags for non-trivial extensions could be useful.

Haven't had a closer look at the BSD BPF code /yet/, so ...

  i) Does BSD have such extensions and if so do we overlap some?

ii) Is it planned to also introduce SO_BPF_EXTENSIONS for BSD kernels
     to have one common api (that i.e. libpcap would then make use of)?

> 	David
>

RE: [PATCH] net: introduce SO_BPF_EXTENSIONS

[David Laight]

> From: Daniel Borkmann 
> On 12/06/2013 10:50 AM, David Laight wrote:
> >> if SO_BPF_EXTENSIONS is supported, than you can assume that all current
> >> extensions are supported.
> >>
> >> No need to consume one bit per feature, as all these features wont ever
> >> disappear from linux.
> >
> > However one of the BSDs could add a subset of the features and
> > wish to advertise the fact.
> > So using extra flags for non-trivial extensions could be useful.
> 
> Haven't had a closer look at the BSD BPF code /yet/, so ...

I've not looked either.

>   i) Does BSD have such extensions and if so do we overlap some?
> 
> ii) Is it planned to also introduce SO_BPF_EXTENSIONS for BSD kernels
>      to have one common api (that i.e. libpcap would then make use of)?

If it is useful to add any of the extensions, and they don't collide
with any other existing changes, then they might be added.
Adding a request that indicates which extensions are supported should
be easier than adding the extensions themselves.
Adding all the Linux extensions at once could be problematic.

	David

Re: [PATCH] net: introduce SO_BPF_EXTENSIONS

[Daniel Borkmann]

On 12/06/2013 12:15 PM, David Laight wrote:
>> From: Daniel Borkmann

>> Haven't had a closer look at the BSD BPF code /yet/, so ...
>
> I've not looked either.
>
>>    i) Does BSD have such extensions and if so do we overlap some?
>>
>> ii) Is it planned to also introduce SO_BPF_EXTENSIONS for BSD kernels
>>       to have one common api (that i.e. libpcap would then make use of)?
>
> If it is useful to add any of the extensions, and they don't collide
> with any other existing changes, then they might be added.
> Adding a request that indicates which extensions are supported should
> be easier than adding the extensions themselves.

Btw, we have aa1113d9f85da5 for that, but I see the point to get all
at once.

Ideally, they shouldn't even be added manually to this getsockopt,
plus we need to be careful of not preventing us in future from adding
additional extensions if they are needed for some good reason (hence,
the 1 bit, but maybe there's another better solution; haven't had
time to think about it so far).

Re: [PATCH] net: introduce SO_BPF_EXTENSIONS

[David Miller]

From: "David Laight" <David.Laight@ACULAB.COM>
Date: Fri, 6 Dec 2013 09:50:49 -0000

>> if SO_BPF_EXTENSIONS is supported, than you can assume that all current
>> extensions are supported.
>> 
>> No need to consume one bit per feature, as all these features wont ever
>> disappear from linux.
> 
> However one of the BSDs could add a subset of the features and
> wish to advertise the fact.
> So using extra flags for non-trivial extensions could be useful.

Sorry, we're not going to accomodate this.

Re: [PATCH] net: introduce SO_BPF_EXTENSIONS

[David Miller]

From: "David Laight" <David.Laight@ACULAB.COM>
Date: Fri, 6 Dec 2013 11:15:58 -0000

>>   i) Does BSD have such extensions and if so do we overlap some?
>> 
>> ii) Is it planned to also introduce SO_BPF_EXTENSIONS for BSD kernels
>>      to have one common api (that i.e. libpcap would then make use of)?
> 
> If it is useful to add any of the extensions, and they don't collide
> with any other existing changes, then they might be added.
> Adding a request that indicates which extensions are supported should
> be easier than adding the extensions themselves.
> Adding all the Linux extensions at once could be problematic.

Again, we're not going to accomodate this, sorry.

Re: [PATCH] net: introduce SO_BPF_EXTENSIONS

[Michal Sekletár]

Not sure I follow. Not going to accommodate, meaning at all or you
just my original approach? If later applies, I'll be happy to rewrite
the patch.

On Fri, Dec 6, 2013 at 6:15 PM, David Miller <davem@davemloft.net> wrote:
> From: "David Laight" <David.Laight@ACULAB.COM>
> Date: Fri, 6 Dec 2013 11:15:58 -0000
>
>>>   i) Does BSD have such extensions and if so do we overlap some?
>>>
>>> ii) Is it planned to also introduce SO_BPF_EXTENSIONS for BSD kernels
>>>      to have one common api (that i.e. libpcap would then make use of)?
>>
>> If it is useful to add any of the extensions, and they don't collide
>> with any other existing changes, then they might be added.
>> Adding a request that indicates which extensions are supported should
>> be easier than adding the extensions themselves.
>> Adding all the Linux extensions at once could be problematic.
>
> Again, we're not going to accomodate this, sorry.

Re: [PATCH] net: introduce SO_BPF_EXTENSIONS

[David Miller]

And please do not top post in the future, thank you.

[PATCH] net: introduce SO_BPF_EXTENSIONS

[Michal Sekletar]

userspace packet capturing libraries (e.g. libpcap) don't have a way how to find
out which BPF extensions are supported by the kernel, except compiling a filter
which uses extensions and trying to apply filter to the socket. This is very
inconvenient.

Therefore this commit introduces new option which can be used as an argument for
getsockopt() and allows one to obtain information about which BPF extensions are
supported by the kernel.

On Tue, Dec 10, 2013 at 1:25 AM, David Miller <davem@davemloft.net> wrote:

> And therefore, you do not need to define any actual bits yet. The
> socket option will for now just return "0", and that will mean that
> all the extensions Linux implements currently are presnet.

Signed-off-by: Michal Sekletar <msekleta@redhat.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: David Miller <davem@davemloft.net>
---
 arch/alpha/include/uapi/asm/socket.h   | 2 ++
 arch/avr32/include/uapi/asm/socket.h   | 2 ++
 arch/cris/include/uapi/asm/socket.h    | 2 ++
 arch/frv/include/uapi/asm/socket.h     | 2 ++
 arch/ia64/include/uapi/asm/socket.h    | 2 ++
 arch/m32r/include/uapi/asm/socket.h    | 2 ++
 arch/mips/include/uapi/asm/socket.h    | 2 ++
 arch/mn10300/include/uapi/asm/socket.h | 2 ++
 arch/parisc/include/uapi/asm/socket.h  | 2 ++
 arch/powerpc/include/uapi/asm/socket.h | 2 ++
 arch/s390/include/uapi/asm/socket.h    | 2 ++
 arch/sparc/include/uapi/asm/socket.h   | 2 ++
 arch/xtensa/include/uapi/asm/socket.h  | 2 ++
 include/net/sock.h                     | 5 +++++
 include/uapi/asm-generic/socket.h      | 2 ++
 net/core/sock.c                        | 4 ++++
 16 files changed, 37 insertions(+)

diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h
index e3a1491..3de1394 100644
--- a/arch/alpha/include/uapi/asm/socket.h
+++ b/arch/alpha/include/uapi/asm/socket.h
@@ -85,4 +85,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _UAPI_ASM_SOCKET_H */
diff --git a/arch/avr32/include/uapi/asm/socket.h b/arch/avr32/include/uapi/asm/socket.h
index cbf902e..6e6cd15 100644
--- a/arch/avr32/include/uapi/asm/socket.h
+++ b/arch/avr32/include/uapi/asm/socket.h
@@ -78,4 +78,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _UAPI__ASM_AVR32_SOCKET_H */
diff --git a/arch/cris/include/uapi/asm/socket.h b/arch/cris/include/uapi/asm/socket.h
index 13829aa..ed94e5e 100644
--- a/arch/cris/include/uapi/asm/socket.h
+++ b/arch/cris/include/uapi/asm/socket.h
@@ -80,6 +80,8 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _ASM_SOCKET_H */
 
 
diff --git a/arch/frv/include/uapi/asm/socket.h b/arch/frv/include/uapi/asm/socket.h
index 5d42997..ca2c6e6 100644
--- a/arch/frv/include/uapi/asm/socket.h
+++ b/arch/frv/include/uapi/asm/socket.h
@@ -78,5 +78,7 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _ASM_SOCKET_H */
 
diff --git a/arch/ia64/include/uapi/asm/socket.h b/arch/ia64/include/uapi/asm/socket.h
index c25302f..a1b49ba 100644
--- a/arch/ia64/include/uapi/asm/socket.h
+++ b/arch/ia64/include/uapi/asm/socket.h
@@ -87,4 +87,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _ASM_IA64_SOCKET_H */
diff --git a/arch/m32r/include/uapi/asm/socket.h b/arch/m32r/include/uapi/asm/socket.h
index 5296665..6c9a24b 100644
--- a/arch/m32r/include/uapi/asm/socket.h
+++ b/arch/m32r/include/uapi/asm/socket.h
@@ -78,4 +78,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _ASM_M32R_SOCKET_H */
diff --git a/arch/mips/include/uapi/asm/socket.h b/arch/mips/include/uapi/asm/socket.h
index 0df9787..a14baa2 100644
--- a/arch/mips/include/uapi/asm/socket.h
+++ b/arch/mips/include/uapi/asm/socket.h
@@ -96,4 +96,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _UAPI_ASM_SOCKET_H */
diff --git a/arch/mn10300/include/uapi/asm/socket.h b/arch/mn10300/include/uapi/asm/socket.h
index 71dedca..6aa3ce1 100644
--- a/arch/mn10300/include/uapi/asm/socket.h
+++ b/arch/mn10300/include/uapi/asm/socket.h
@@ -78,4 +78,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/parisc/include/uapi/asm/socket.h b/arch/parisc/include/uapi/asm/socket.h
index f33113a..a586f61 100644
--- a/arch/parisc/include/uapi/asm/socket.h
+++ b/arch/parisc/include/uapi/asm/socket.h
@@ -77,4 +77,6 @@
 
 #define SO_MAX_PACING_RATE	0x4048
 
+#define SO_BPF_EXTENSIONS	0x4029
+
 #endif /* _UAPI_ASM_SOCKET_H */
diff --git a/arch/powerpc/include/uapi/asm/socket.h b/arch/powerpc/include/uapi/asm/socket.h
index fa69832..a9c3e2e 100644
--- a/arch/powerpc/include/uapi/asm/socket.h
+++ b/arch/powerpc/include/uapi/asm/socket.h
@@ -85,4 +85,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif	/* _ASM_POWERPC_SOCKET_H */
diff --git a/arch/s390/include/uapi/asm/socket.h b/arch/s390/include/uapi/asm/socket.h
index c286c2e..e031332 100644
--- a/arch/s390/include/uapi/asm/socket.h
+++ b/arch/s390/include/uapi/asm/socket.h
@@ -84,4 +84,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/sparc/include/uapi/asm/socket.h b/arch/sparc/include/uapi/asm/socket.h
index 0f21e9a..54d9608 100644
--- a/arch/sparc/include/uapi/asm/socket.h
+++ b/arch/sparc/include/uapi/asm/socket.h
@@ -74,6 +74,8 @@
 
 #define SO_MAX_PACING_RATE	0x0031
 
+#define SO_BPF_EXTENSIONS	0x0032
+
 /* Security levels - as per NRL IPv6 - don't actually do anything */
 #define SO_SECURITY_AUTHENTICATION		0x5001
 #define SO_SECURITY_ENCRYPTION_TRANSPORT	0x5002
diff --git a/arch/xtensa/include/uapi/asm/socket.h b/arch/xtensa/include/uapi/asm/socket.h
index 7db5c22..39acec0 100644
--- a/arch/xtensa/include/uapi/asm/socket.h
+++ b/arch/xtensa/include/uapi/asm/socket.h
@@ -89,4 +89,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif	/* _XTENSA_SOCKET_H */
diff --git a/include/net/sock.h b/include/net/sock.h
index 5c3f7c3..ae8ff52 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2292,4 +2292,9 @@ extern int sysctl_optmem_max;
 extern __u32 sysctl_wmem_default;
 extern __u32 sysctl_rmem_default;
 
+static inline int bpf_get_extensions(void)
+{
+	return 0;
+}
+
 #endif	/* _SOCK_H */
diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
index 38f14d0..ea0796b 100644
--- a/include/uapi/asm-generic/socket.h
+++ b/include/uapi/asm-generic/socket.h
@@ -80,4 +80,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* __ASM_GENERIC_SOCKET_H */
diff --git a/net/core/sock.c b/net/core/sock.c
index 85ad6f0..70e5a6e 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1167,6 +1167,10 @@ int sock_getsockopt(struct socket *sock, int level, int optname,
 		v.val = sock_flag(sk, SOCK_FILTER_LOCKED);
 		break;
 
+	case SO_BPF_EXTENSIONS:
+		v.val = bpf_get_extensions();
+		break;
+
 	case SO_SELECT_ERR_QUEUE:
 		v.val = sock_flag(sk, SOCK_SELECT_ERR_QUEUE);
 		break;
-- 
1.8.4.2

Re: [PATCH] net: introduce SO_BPF_EXTENSIONS

[Daniel Borkmann]

On 01/16/2014 05:14 PM, Michal Sekletar wrote:
> userspace packet capturing libraries (e.g. libpcap) don't have a way how to find
> out which BPF extensions are supported by the kernel, except compiling a filter
> which uses extensions and trying to apply filter to the socket. This is very
> inconvenient.
>
> Therefore this commit introduces new option which can be used as an argument for
> getsockopt() and allows one to obtain information about which BPF extensions are
> supported by the kernel.
>
> On Tue, Dec 10, 2013 at 1:25 AM, David Miller <davem@davemloft.net> wrote:
>
>> And therefore, you do not need to define any actual bits yet. The
>> socket option will for now just return "0", and that will mean that
>> all the extensions Linux implements currently are presnet.
>
> Signed-off-by: Michal Sekletar <msekleta@redhat.com>
> Cc: Michael Kerrisk <mtk.manpages@gmail.com>
> Cc: Daniel Borkmann <dborkman@redhat.com>
> Cc: David Miller <davem@davemloft.net>
> ---
>   arch/alpha/include/uapi/asm/socket.h   | 2 ++
>   arch/avr32/include/uapi/asm/socket.h   | 2 ++
>   arch/cris/include/uapi/asm/socket.h    | 2 ++
>   arch/frv/include/uapi/asm/socket.h     | 2 ++
>   arch/ia64/include/uapi/asm/socket.h    | 2 ++
>   arch/m32r/include/uapi/asm/socket.h    | 2 ++
>   arch/mips/include/uapi/asm/socket.h    | 2 ++
>   arch/mn10300/include/uapi/asm/socket.h | 2 ++
>   arch/parisc/include/uapi/asm/socket.h  | 2 ++
>   arch/powerpc/include/uapi/asm/socket.h | 2 ++
>   arch/s390/include/uapi/asm/socket.h    | 2 ++
>   arch/sparc/include/uapi/asm/socket.h   | 2 ++
>   arch/xtensa/include/uapi/asm/socket.h  | 2 ++
>   include/net/sock.h                     | 5 +++++
>   include/uapi/asm-generic/socket.h      | 2 ++
>   net/core/sock.c                        | 4 ++++
>   16 files changed, 37 insertions(+)
>
...
> --- a/include/net/sock.h
> +++ b/include/net/sock.h
> @@ -2292,4 +2292,9 @@ extern int sysctl_optmem_max;
>   extern __u32 sysctl_wmem_default;
>   extern __u32 sysctl_rmem_default;
>
> +static inline int bpf_get_extensions(void)
> +{
> +	return 0;
> +}
> +

This should rather be in: include/linux/filter.h

And then, maybe be renamed into something like bpf_tell_extensions()
for example, but that's just nit.

Also, please add a comment, saying if people add new extensions, they
need to enumerate them within this function from now on so that user
space who enquires for that can be made aware of.

Still, grepping through latest libpcap sources, tells me, so far over
the years they have included SKF_AD_PROTOCOL and SKF_AD_PKTTYPE, wow!

That's very disappointing, so I have high hopes with this getsockopt().

;)

Thanks,

Daniel

>   #endif	/* _SOCK_H */
> diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
> index 38f14d0..ea0796b 100644
> --- a/include/uapi/asm-generic/socket.h
> +++ b/include/uapi/asm-generic/socket.h
> @@ -80,4 +80,6 @@
>
>   #define SO_MAX_PACING_RATE	47
>
> +#define SO_BPF_EXTENSIONS	48
> +
>   #endif /* __ASM_GENERIC_SOCKET_H */
> diff --git a/net/core/sock.c b/net/core/sock.c
> index 85ad6f0..70e5a6e 100644
> --- a/net/core/sock.c
> +++ b/net/core/sock.c
> @@ -1167,6 +1167,10 @@ int sock_getsockopt(struct socket *sock, int level, int optname,
>   		v.val = sock_flag(sk, SOCK_FILTER_LOCKED);
>   		break;
>
> +	case SO_BPF_EXTENSIONS:
> +		v.val = bpf_get_extensions();
> +		break;
> +
>   	case SO_SELECT_ERR_QUEUE:
>   		v.val = sock_flag(sk, SOCK_SELECT_ERR_QUEUE);
>   		break;
>

[PATCH] net: introduce SO_BPF_EXTENSIONS

[Michal Sekletar]

userspace packet capturing libraries (e.g. libpcap) don't have a way how to find
out which BPF extensions are supported by the kernel, except compiling a filter
which uses extensions and trying to apply filter to the socket. This is very
inconvenient.

Therefore this commit introduces new option which can be used as an argument for
getsockopt() and allows one to obtain information about which BPF extensions are
supported by the kernel.

On Tue, Dec 10, 2013 at 1:25 AM, David Miller <davem@davemloft.net> wrote:

> And therefore, you do not need to define any actual bits yet. The
> socket option will for now just return "0", and that will mean that
> all the extensions Linux implements currently are presnet.

Signed-off-by: Michal Sekletar <msekleta@redhat.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: David Miller <davem@davemloft.net>
---
 arch/alpha/include/uapi/asm/socket.h   |  2 ++
 arch/avr32/include/uapi/asm/socket.h   |  2 ++
 arch/cris/include/uapi/asm/socket.h    |  2 ++
 arch/frv/include/uapi/asm/socket.h     |  2 ++
 arch/ia64/include/uapi/asm/socket.h    |  2 ++
 arch/m32r/include/uapi/asm/socket.h    |  2 ++
 arch/mips/include/uapi/asm/socket.h    |  2 ++
 arch/mn10300/include/uapi/asm/socket.h |  2 ++
 arch/parisc/include/uapi/asm/socket.h  |  2 ++
 arch/powerpc/include/uapi/asm/socket.h |  2 ++
 arch/s390/include/uapi/asm/socket.h    |  2 ++
 arch/sparc/include/uapi/asm/socket.h   |  2 ++
 arch/xtensa/include/uapi/asm/socket.h  |  2 ++
 include/linux/filter.h                 | 10 ++++++++++
 include/uapi/asm-generic/socket.h      |  2 ++
 net/core/sock.c                        |  4 ++++
 16 files changed, 42 insertions(+)

diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h
index e3a1491..3de1394 100644
--- a/arch/alpha/include/uapi/asm/socket.h
+++ b/arch/alpha/include/uapi/asm/socket.h
@@ -85,4 +85,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _UAPI_ASM_SOCKET_H */
diff --git a/arch/avr32/include/uapi/asm/socket.h b/arch/avr32/include/uapi/asm/socket.h
index cbf902e..6e6cd15 100644
--- a/arch/avr32/include/uapi/asm/socket.h
+++ b/arch/avr32/include/uapi/asm/socket.h
@@ -78,4 +78,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _UAPI__ASM_AVR32_SOCKET_H */
diff --git a/arch/cris/include/uapi/asm/socket.h b/arch/cris/include/uapi/asm/socket.h
index 13829aa..ed94e5e 100644
--- a/arch/cris/include/uapi/asm/socket.h
+++ b/arch/cris/include/uapi/asm/socket.h
@@ -80,6 +80,8 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _ASM_SOCKET_H */
 
 
diff --git a/arch/frv/include/uapi/asm/socket.h b/arch/frv/include/uapi/asm/socket.h
index 5d42997..ca2c6e6 100644
--- a/arch/frv/include/uapi/asm/socket.h
+++ b/arch/frv/include/uapi/asm/socket.h
@@ -78,5 +78,7 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _ASM_SOCKET_H */
 
diff --git a/arch/ia64/include/uapi/asm/socket.h b/arch/ia64/include/uapi/asm/socket.h
index c25302f..a1b49ba 100644
--- a/arch/ia64/include/uapi/asm/socket.h
+++ b/arch/ia64/include/uapi/asm/socket.h
@@ -87,4 +87,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _ASM_IA64_SOCKET_H */
diff --git a/arch/m32r/include/uapi/asm/socket.h b/arch/m32r/include/uapi/asm/socket.h
index 5296665..6c9a24b 100644
--- a/arch/m32r/include/uapi/asm/socket.h
+++ b/arch/m32r/include/uapi/asm/socket.h
@@ -78,4 +78,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _ASM_M32R_SOCKET_H */
diff --git a/arch/mips/include/uapi/asm/socket.h b/arch/mips/include/uapi/asm/socket.h
index 0df9787..a14baa2 100644
--- a/arch/mips/include/uapi/asm/socket.h
+++ b/arch/mips/include/uapi/asm/socket.h
@@ -96,4 +96,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _UAPI_ASM_SOCKET_H */
diff --git a/arch/mn10300/include/uapi/asm/socket.h b/arch/mn10300/include/uapi/asm/socket.h
index 71dedca..6aa3ce1 100644
--- a/arch/mn10300/include/uapi/asm/socket.h
+++ b/arch/mn10300/include/uapi/asm/socket.h
@@ -78,4 +78,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/parisc/include/uapi/asm/socket.h b/arch/parisc/include/uapi/asm/socket.h
index f33113a..a586f61 100644
--- a/arch/parisc/include/uapi/asm/socket.h
+++ b/arch/parisc/include/uapi/asm/socket.h
@@ -77,4 +77,6 @@
 
 #define SO_MAX_PACING_RATE	0x4048
 
+#define SO_BPF_EXTENSIONS	0x4029
+
 #endif /* _UAPI_ASM_SOCKET_H */
diff --git a/arch/powerpc/include/uapi/asm/socket.h b/arch/powerpc/include/uapi/asm/socket.h
index fa69832..a9c3e2e 100644
--- a/arch/powerpc/include/uapi/asm/socket.h
+++ b/arch/powerpc/include/uapi/asm/socket.h
@@ -85,4 +85,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif	/* _ASM_POWERPC_SOCKET_H */
diff --git a/arch/s390/include/uapi/asm/socket.h b/arch/s390/include/uapi/asm/socket.h
index c286c2e..e031332 100644
--- a/arch/s390/include/uapi/asm/socket.h
+++ b/arch/s390/include/uapi/asm/socket.h
@@ -84,4 +84,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/sparc/include/uapi/asm/socket.h b/arch/sparc/include/uapi/asm/socket.h
index 0f21e9a..54d9608 100644
--- a/arch/sparc/include/uapi/asm/socket.h
+++ b/arch/sparc/include/uapi/asm/socket.h
@@ -74,6 +74,8 @@
 
 #define SO_MAX_PACING_RATE	0x0031
 
+#define SO_BPF_EXTENSIONS	0x0032
+
 /* Security levels - as per NRL IPv6 - don't actually do anything */
 #define SO_SECURITY_AUTHENTICATION		0x5001
 #define SO_SECURITY_ENCRYPTION_TRANSPORT	0x5002
diff --git a/arch/xtensa/include/uapi/asm/socket.h b/arch/xtensa/include/uapi/asm/socket.h
index 7db5c22..39acec0 100644
--- a/arch/xtensa/include/uapi/asm/socket.h
+++ b/arch/xtensa/include/uapi/asm/socket.h
@@ -89,4 +89,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif	/* _XTENSA_SOCKET_H */
diff --git a/include/linux/filter.h b/include/linux/filter.h
index ff4e40c..3c9a7fc 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -83,6 +83,16 @@ static inline void bpf_jit_free(struct sk_filter *fp)
 #define SK_RUN_FILTER(FILTER, SKB) sk_run_filter(SKB, FILTER->insns)
 #endif
 
+static inline int bpf_tell_extensions(void)
+{
+        /* When adding new BPF extension it is necessary to enumerate it here, so
+         * userspace software which wants to know what is supported can do so by inspecting
+         * return value of this function
+         */
+
+        return 0;
+}
+
 enum {
 	BPF_S_RET_K = 1,
 	BPF_S_RET_A,
diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
index 38f14d0..ea0796b 100644
--- a/include/uapi/asm-generic/socket.h
+++ b/include/uapi/asm-generic/socket.h
@@ -80,4 +80,6 @@
 
 #define SO_MAX_PACING_RATE	47
 
+#define SO_BPF_EXTENSIONS	48
+
 #endif /* __ASM_GENERIC_SOCKET_H */
diff --git a/net/core/sock.c b/net/core/sock.c
index 85ad6f0..4a32e52 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1167,6 +1167,10 @@ int sock_getsockopt(struct socket *sock, int level, int optname,
 		v.val = sock_flag(sk, SOCK_FILTER_LOCKED);
 		break;
 
+	case SO_BPF_EXTENSIONS:
+		v.val = bpf_tell_extensions();
+		break;
+
 	case SO_SELECT_ERR_QUEUE:
 		v.val = sock_flag(sk, SOCK_SELECT_ERR_QUEUE);
 		break;
-- 
1.8.4.2

Re: [PATCH] net: introduce SO_BPF_EXTENSIONS

[Michal Sekletar]

On Thu, Jan 16, 2014 at 05:41:46PM +0100, Daniel Borkmann wrote:
> On 01/16/2014 05:14 PM, Michal Sekletar wrote:
> >userspace packet capturing libraries (e.g. libpcap) don't have a way how to find
> >out which BPF extensions are supported by the kernel, except compiling a filter
> >which uses extensions and trying to apply filter to the socket. This is very
> >inconvenient.
> >
> >Therefore this commit introduces new option which can be used as an argument for
> >getsockopt() and allows one to obtain information about which BPF extensions are
> >supported by the kernel.
> >
> >On Tue, Dec 10, 2013 at 1:25 AM, David Miller <davem@davemloft.net> wrote:
> >
> >>And therefore, you do not need to define any actual bits yet. The
> >>socket option will for now just return "0", and that will mean that
> >>all the extensions Linux implements currently are presnet.
> >
> >Signed-off-by: Michal Sekletar <msekleta@redhat.com>
> >Cc: Michael Kerrisk <mtk.manpages@gmail.com>
> >Cc: Daniel Borkmann <dborkman@redhat.com>
> >Cc: David Miller <davem@davemloft.net>
> >---
> >  arch/alpha/include/uapi/asm/socket.h   | 2 ++
> >  arch/avr32/include/uapi/asm/socket.h   | 2 ++
> >  arch/cris/include/uapi/asm/socket.h    | 2 ++
> >  arch/frv/include/uapi/asm/socket.h     | 2 ++
> >  arch/ia64/include/uapi/asm/socket.h    | 2 ++
> >  arch/m32r/include/uapi/asm/socket.h    | 2 ++
> >  arch/mips/include/uapi/asm/socket.h    | 2 ++
> >  arch/mn10300/include/uapi/asm/socket.h | 2 ++
> >  arch/parisc/include/uapi/asm/socket.h  | 2 ++
> >  arch/powerpc/include/uapi/asm/socket.h | 2 ++
> >  arch/s390/include/uapi/asm/socket.h    | 2 ++
> >  arch/sparc/include/uapi/asm/socket.h   | 2 ++
> >  arch/xtensa/include/uapi/asm/socket.h  | 2 ++
> >  include/net/sock.h                     | 5 +++++
> >  include/uapi/asm-generic/socket.h      | 2 ++
> >  net/core/sock.c                        | 4 ++++
> >  16 files changed, 37 insertions(+)
> >
> ...
> >--- a/include/net/sock.h
> >+++ b/include/net/sock.h
> >@@ -2292,4 +2292,9 @@ extern int sysctl_optmem_max;
> >  extern __u32 sysctl_wmem_default;
> >  extern __u32 sysctl_rmem_default;
> >
> >+static inline int bpf_get_extensions(void)
> >+{
> >+	return 0;
> >+}
> >+
> 
> This should rather be in: include/linux/filter.h

Yes, having that function there makes more sense.

> 
> And then, maybe be renamed into something like bpf_tell_extensions()
> for example, but that's just nit.

Renamed.

> 
> Also, please add a comment, saying if people add new extensions, they
> need to enumerate them within this function from now on so that user
> space who enquires for that can be made aware of.

Let me know if even more explanatory comment is desired.

> 
> Still, grepping through latest libpcap sources, tells me, so far over
> the years they have included SKF_AD_PROTOCOL and SKF_AD_PKTTYPE, wow!
> 
> That's very disappointing, so I have high hopes with this getsockopt().
> 
> ;)
> 
> Thanks,

Thank you for the review. Btw, what do you think about define for parisc? I am
not sure I grok 0x4048 for SO_MAX_PACING_RATE and hence not sure about 0x4029
for SO_BPF_EXTENSIONS.

> 
> Daniel

Michal

> 
> >  #endif	/* _SOCK_H */
> >diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
> >index 38f14d0..ea0796b 100644
> >--- a/include/uapi/asm-generic/socket.h
> >+++ b/include/uapi/asm-generic/socket.h
> >@@ -80,4 +80,6 @@
> >
> >  #define SO_MAX_PACING_RATE	47
> >
> >+#define SO_BPF_EXTENSIONS	48
> >+
> >  #endif /* __ASM_GENERIC_SOCKET_H */
> >diff --git a/net/core/sock.c b/net/core/sock.c
> >index 85ad6f0..70e5a6e 100644
> >--- a/net/core/sock.c
> >+++ b/net/core/sock.c
> >@@ -1167,6 +1167,10 @@ int sock_getsockopt(struct socket *sock, int level, int optname,
> >  		v.val = sock_flag(sk, SOCK_FILTER_LOCKED);
> >  		break;
> >
> >+	case SO_BPF_EXTENSIONS:
> >+		v.val = bpf_get_extensions();
> >+		break;
> >+
> >  	case SO_SELECT_ERR_QUEUE:
> >  		v.val = sock_flag(sk, SOCK_SELECT_ERR_QUEUE);
> >  		break;
> >

Re: [PATCH] net: introduce SO_BPF_EXTENSIONS

[Daniel Borkmann]

On 01/16/2014 06:26 PM, Michal Sekletar wrote:
> On Thu, Jan 16, 2014 at 05:41:46PM +0100, Daniel Borkmann wrote:
>> On 01/16/2014 05:14 PM, Michal Sekletar wrote:
>>> userspace packet capturing libraries (e.g. libpcap) don't have a way how to find
>>> out which BPF extensions are supported by the kernel, except compiling a filter
>>> which uses extensions and trying to apply filter to the socket. This is very
>>> inconvenient.
>>>
>>> Therefore this commit introduces new option which can be used as an argument for
>>> getsockopt() and allows one to obtain information about which BPF extensions are
>>> supported by the kernel.
>>>
>>> On Tue, Dec 10, 2013 at 1:25 AM, David Miller <davem@davemloft.net> wrote:
>>>
>>>> And therefore, you do not need to define any actual bits yet. The
>>>> socket option will for now just return "0", and that will mean that
>>>> all the extensions Linux implements currently are presnet.
>>>
>>> Signed-off-by: Michal Sekletar <msekleta@redhat.com>
>>> Cc: Michael Kerrisk <mtk.manpages@gmail.com>
>>> Cc: Daniel Borkmann <dborkman@redhat.com>
>>> Cc: David Miller <davem@davemloft.net>
>>> ---
>>>   arch/alpha/include/uapi/asm/socket.h   | 2 ++
>>>   arch/avr32/include/uapi/asm/socket.h   | 2 ++
>>>   arch/cris/include/uapi/asm/socket.h    | 2 ++
>>>   arch/frv/include/uapi/asm/socket.h     | 2 ++
>>>   arch/ia64/include/uapi/asm/socket.h    | 2 ++
>>>   arch/m32r/include/uapi/asm/socket.h    | 2 ++
>>>   arch/mips/include/uapi/asm/socket.h    | 2 ++
>>>   arch/mn10300/include/uapi/asm/socket.h | 2 ++
>>>   arch/parisc/include/uapi/asm/socket.h  | 2 ++
>>>   arch/powerpc/include/uapi/asm/socket.h | 2 ++
>>>   arch/s390/include/uapi/asm/socket.h    | 2 ++
>>>   arch/sparc/include/uapi/asm/socket.h   | 2 ++
>>>   arch/xtensa/include/uapi/asm/socket.h  | 2 ++
>>>   include/net/sock.h                     | 5 +++++
>>>   include/uapi/asm-generic/socket.h      | 2 ++
>>>   net/core/sock.c                        | 4 ++++
>>>   16 files changed, 37 insertions(+)
>>>
>> ...
>>> --- a/include/net/sock.h
>>> +++ b/include/net/sock.h
>>> @@ -2292,4 +2292,9 @@ extern int sysctl_optmem_max;
>>>   extern __u32 sysctl_wmem_default;
>>>   extern __u32 sysctl_rmem_default;
>>>
>>> +static inline int bpf_get_extensions(void)
>>> +{
>>> +	return 0;
>>> +}
>>> +
>>
>> This should rather be in: include/linux/filter.h
>
> Yes, having that function there makes more sense.
>
>>
>> And then, maybe be renamed into something like bpf_tell_extensions()
>> for example, but that's just nit.
>
> Renamed.
>
>>
>> Also, please add a comment, saying if people add new extensions, they
>> need to enumerate them within this function from now on so that user
>> space who enquires for that can be made aware of.
>
> Let me know if even more explanatory comment is desired.

I think that looks good.

>> Still, grepping through latest libpcap sources, tells me, so far over
>> the years they have included SKF_AD_PROTOCOL and SKF_AD_PKTTYPE, wow!
>>
>> That's very disappointing, so I have high hopes with this getsockopt().
>>
>> ;)
>>
>> Thanks,
>
> Thank you for the review. Btw, what do you think about define for parisc? I am

Yes, saw that in the patch and had similar thoughts.

> not sure I grok 0x4048 for SO_MAX_PACING_RATE and hence not sure about 0x4029
> for SO_BPF_EXTENSIONS.

Hmm, maybe typo; SO_MAX_PACING_RATE should have been a 0x4028 ?

Re: [PATCH] net: introduce SO_BPF_EXTENSIONS

[Eric Dumazet]

On Thu, 2014-01-16 at 19:34 +0100, Daniel Borkmann wrote:

> > Thank you for the review. Btw, what do you think about define for parisc? I am
> 
> Yes, saw that in the patch and had similar thoughts.
> 
> > not sure I grok 0x4048 for SO_MAX_PACING_RATE and hence not sure about 0x4029
> > for SO_BPF_EXTENSIONS.
> 
> Hmm, maybe typo; SO_MAX_PACING_RATE should have been a 0x4028 ?

Indeed it was a typo.

I think its time to change this, as this was added for linux-3.13

Re: [PATCH] net: introduce SO_BPF_EXTENSIONS

[Daniel Borkmann]

On 01/16/2014 07:49 PM, Eric Dumazet wrote:
> On Thu, 2014-01-16 at 19:34 +0100, Daniel Borkmann wrote:
>
>>> Thank you for the review. Btw, what do you think about define for parisc? I am
>>
>> Yes, saw that in the patch and had similar thoughts.
>>
>>> not sure I grok 0x4048 for SO_MAX_PACING_RATE and hence not sure about 0x4029
>>> for SO_BPF_EXTENSIONS.
>>
>> Hmm, maybe typo; SO_MAX_PACING_RATE should have been a 0x4028 ?
>
> Indeed it was a typo.
>
> I think its time to change this, as this was added for linux-3.13

Ok, are you sending out a patch?

Thanks,

Daniel

Re: [PATCH] net: introduce SO_BPF_EXTENSIONS

[Eric Dumazet]

On Thu, 2014-01-16 at 19:52 +0100, Daniel Borkmann wrote:
> On 01/16/2014 07:49 PM, Eric Dumazet wrote:
> > On Thu, 2014-01-16 at 19:34 +0100, Daniel Borkmann wrote:
> >
> >>> Thank you for the review. Btw, what do you think about define for parisc? I am
> >>
> >> Yes, saw that in the patch and had similar thoughts.
> >>
> >>> not sure I grok 0x4048 for SO_MAX_PACING_RATE and hence not sure about 0x4029
> >>> for SO_BPF_EXTENSIONS.
> >>
> >> Hmm, maybe typo; SO_MAX_PACING_RATE should have been a 0x4028 ?
> >
> > Indeed it was a typo.
> >
> > I think its time to change this, as this was added for linux-3.13
> 
> Ok, are you sending out a patch?

Yes, I will, thanks !

[PATCH] parisc: fix SO_MAX_PACING_RATE typo

[Eric Dumazet]

From: Eric Dumazet <edumazet@google.com>

SO_MAX_PACING_RATE definition on parisc got a typo.
Its not too late to fix it, before 3.13 is official.

Fixes: 62748f32d501 ("net: introduce SO_MAX_PACING_RATE")
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 arch/parisc/include/uapi/asm/socket.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/parisc/include/uapi/asm/socket.h b/arch/parisc/include/uapi/asm/socket.h
index f33113a6141e..70b3674dac4e 100644
--- a/arch/parisc/include/uapi/asm/socket.h
+++ b/arch/parisc/include/uapi/asm/socket.h
@@ -75,6 +75,6 @@
 
 #define SO_BUSY_POLL		0x4027
 
-#define SO_MAX_PACING_RATE	0x4048
+#define SO_MAX_PACING_RATE	0x4028
 
 #endif /* _UAPI_ASM_SOCKET_H */

Re: [PATCH] net: introduce SO_BPF_EXTENSIONS

[Daniel Borkmann]

On 01/16/2014 07:34 PM, Daniel Borkmann wrote:
> On 01/16/2014 06:26 PM, Michal Sekletar wrote:
>> On Thu, Jan 16, 2014 at 05:41:46PM +0100, Daniel Borkmann wrote:
>>> On 01/16/2014 05:14 PM, Michal Sekletar wrote:
>>>> userspace packet capturing libraries (e.g. libpcap) don't have a way how to find
>>>> out which BPF extensions are supported by the kernel, except compiling a filter
>>>> which uses extensions and trying to apply filter to the socket. This is very
>>>> inconvenient.
>>>>
>>>> Therefore this commit introduces new option which can be used as an argument for
>>>> getsockopt() and allows one to obtain information about which BPF extensions are
>>>> supported by the kernel.
>>>>
>>>> On Tue, Dec 10, 2013 at 1:25 AM, David Miller <davem@davemloft.net> wrote:
>>>>
>>>>> And therefore, you do not need to define any actual bits yet. The
>>>>> socket option will for now just return "0", and that will mean that
>>>>> all the extensions Linux implements currently are presnet.
>>>>
>>>> Signed-off-by: Michal Sekletar <msekleta@redhat.com>
>>>> Cc: Michael Kerrisk <mtk.manpages@gmail.com>
>>>> Cc: Daniel Borkmann <dborkman@redhat.com>
>>>> Cc: David Miller <davem@davemloft.net>
>>>> ---
>>>>   arch/alpha/include/uapi/asm/socket.h   | 2 ++
>>>>   arch/avr32/include/uapi/asm/socket.h   | 2 ++
>>>>   arch/cris/include/uapi/asm/socket.h    | 2 ++
>>>>   arch/frv/include/uapi/asm/socket.h     | 2 ++
>>>>   arch/ia64/include/uapi/asm/socket.h    | 2 ++
>>>>   arch/m32r/include/uapi/asm/socket.h    | 2 ++
>>>>   arch/mips/include/uapi/asm/socket.h    | 2 ++
>>>>   arch/mn10300/include/uapi/asm/socket.h | 2 ++
>>>>   arch/parisc/include/uapi/asm/socket.h  | 2 ++
>>>>   arch/powerpc/include/uapi/asm/socket.h | 2 ++
>>>>   arch/s390/include/uapi/asm/socket.h    | 2 ++
>>>>   arch/sparc/include/uapi/asm/socket.h   | 2 ++
>>>>   arch/xtensa/include/uapi/asm/socket.h  | 2 ++
>>>>   include/net/sock.h                     | 5 +++++
>>>>   include/uapi/asm-generic/socket.h      | 2 ++
>>>>   net/core/sock.c                        | 4 ++++
>>>>   16 files changed, 37 insertions(+)
>>>>
>>> ...
>>>> --- a/include/net/sock.h
>>>> +++ b/include/net/sock.h
>>>> @@ -2292,4 +2292,9 @@ extern int sysctl_optmem_max;
>>>>   extern __u32 sysctl_wmem_default;
>>>>   extern __u32 sysctl_rmem_default;
>>>>
>>>> +static inline int bpf_get_extensions(void)
>>>> +{
>>>> +    return 0;
>>>> +}
>>>> +
>>>
>>> This should rather be in: include/linux/filter.h
>>
>> Yes, having that function there makes more sense.
>>
>>>
>>> And then, maybe be renamed into something like bpf_tell_extensions()
>>> for example, but that's just nit.
>>
>> Renamed.
>>
>>>
>>> Also, please add a comment, saying if people add new extensions, they
>>> need to enumerate them within this function from now on so that user
>>> space who enquires for that can be made aware of.
>>
>> Let me know if even more explanatory comment is desired.
>
> I think that looks good.

Ok, then it seems you need to put your changes on top of [1]; and
0x4029 is fine then.

Sine you have to rebase anyway, and since I just noticed in your v2
patch [2] ... In function bpf_tell_extensions(), you need to convert
your whitespaces to tab, see Documentation/CodingStyle. While you're
at it, also try to line-break the comment at around 80 chars.

Otherwise your patch looks good, thanks Michal.

   [1] http://patchwork.ozlabs.org/patch/311829/
   [2] http://patchwork.ozlabs.org/patch/311790/

>>> Still, grepping through latest libpcap sources, tells me, so far over
>>> the years they have included SKF_AD_PROTOCOL and SKF_AD_PKTTYPE, wow!
>>>
>>> That's very disappointing, so I have high hopes with this getsockopt().
>>>
>>> ;)
>>>
>>> Thanks,
>>
>> Thank you for the review. Btw, what do you think about define for parisc? I am
>
> Yes, saw that in the patch and had similar thoughts.
>
>> not sure I grok 0x4048 for SO_MAX_PACING_RATE and hence not sure about 0x4029
>> for SO_BPF_EXTENSIONS.
>
> Hmm, maybe typo; SO_MAX_PACING_RATE should have been a 0x4028 ?
> --
> To unsubscribe from this list: send the line "unsubscribe netdev" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH] parisc: fix SO_MAX_PACING_RATE typo

[David Miller]

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 16 Jan 2014 11:15:12 -0800

> From: Eric Dumazet <edumazet@google.com>
> 
> SO_MAX_PACING_RATE definition on parisc got a typo.
> Its not too late to fix it, before 3.13 is official.
> 
> Fixes: 62748f32d501 ("net: introduce SO_MAX_PACING_RATE")
> Signed-off-by: Eric Dumazet <edumazet@google.com>

Applied, thanks.