* [PATCH net-next] net: define and implement new SOL_SOCKET SO_RX_IFINDEX option
@ 2024-10-24 15:41 Maciej Żenczykowski
2024-10-24 15:44 ` Maciej Żenczykowski
0 siblings, 1 reply; 3+ messages in thread
From: Maciej Żenczykowski @ 2024-10-24 15:41 UTC (permalink / raw)
To: Maciej Żenczykowski
Cc: Linux Network Development Mailing List, David S . Miller,
Eric Dumazet, Jakub Kicinski, Paolo Abeni,
Maciej Żenczykowski, Lorenzo Colitti
This is currently only implemented for TCP and is not
guaranteed to return correct information for a multitude
of reasons (including multipath reception), but there are
scenarios where it is useful: in particular a strong host
model where connections are only viable via a single interface,
for example a VPN interface. One could for example choose
to use this to SO_BINDTODEVICE.
Test:
// Python 2.7.18 (default, Jul 13 2022, 18:14:36)
import socket
SO_RX_IFINDEX=82
s = socket.socket(socket.AF_INET6, socket.SOCK_STREAM, 0)
c = socket.socket(socket.AF_INET6, socket.SOCK_STREAM, 0)
s.bind(('::', 8888))
s.listen(128)
c.connect(('::', 8888))
a = s.accept()
print a # (<socket._socketobject object>, ('::1', 58144, 0, 0))
p=a[0]
p.getsockname() # ('::1', 8888, 0, 0)
p.getpeername() # ('::1', 58144, 0, 0)
c.getsockname() # ('::1', 58144, 0, 0)
c.getpeername() # ('::1', 8888, 0, 0)
p.getsockopt(socket.SOL_SOCKET, SO_RX_IFINDEX) # 1 (lo)
c.getsockopt(socket.SOL_SOCKET, SO_RX_IFINDEX) # 0 (unknown)
c.send(b'X') # 1
p.recv(2) # 'X'
p.getsockopt(socket.SOL_SOCKET, SO_RX_IFINDEX) # 1 (lo)
c.getsockopt(socket.SOL_SOCKET, SO_RX_IFINDEX) # 0 (unknown)
p.send(b'Z') # 1
c.recv(2) # 'Z'
p.getsockopt(socket.SOL_SOCKET, SO_RX_IFINDEX) # 1 (lo)
c.getsockopt(socket.SOL_SOCKET, SO_RX_IFINDEX) # 1 (lo)
Which shows we should possibly fix the 3-way handshake SYN-ACK
to set sk->sk_rx_dst_ifindex.
Cc: Lorenzo Colitti <lorenzo@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Maciej Żenczykowski <maze@google.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 | 4 ++++
6 files changed, 14 insertions(+)
diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h
index 302507bf9b5d..5f139b095a49 100644
--- a/arch/alpha/include/uapi/asm/socket.h
+++ b/arch/alpha/include/uapi/asm/socket.h
@@ -148,6 +148,8 @@
#define SCM_TS_OPT_ID 81
+#define SO_RX_IFINDEX 82
+
#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 d118d4731580..ff25d24b4dea 100644
--- a/arch/mips/include/uapi/asm/socket.h
+++ b/arch/mips/include/uapi/asm/socket.h
@@ -159,6 +159,8 @@
#define SCM_TS_OPT_ID 81
+#define SO_RX_IFINDEX 82
+
#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 d268d69bfcd2..3f89c388e356 100644
--- a/arch/parisc/include/uapi/asm/socket.h
+++ b/arch/parisc/include/uapi/asm/socket.h
@@ -140,6 +140,8 @@
#define SCM_TS_OPT_ID 0x404C
+#define SO_RX_IFINDEX 82
+
#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 113cd9f353e3..f1af74f5f1ad 100644
--- a/arch/sparc/include/uapi/asm/socket.h
+++ b/arch/sparc/include/uapi/asm/socket.h
@@ -141,6 +141,8 @@
#define SCM_TS_OPT_ID 0x005a
+#define SO_RX_IFINDEX 0x005b
+
#if !defined(__KERNEL__)
diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
index deacfd6dd197..b16c69e22606 100644
--- a/include/uapi/asm-generic/socket.h
+++ b/include/uapi/asm-generic/socket.h
@@ -143,6 +143,8 @@
#define SCM_TS_OPT_ID 81
+#define SO_RX_IFINDEX 82
+
#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 7f398bd07fb7..6c985413c21f 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1932,6 +1932,10 @@ int sk_getsockopt(struct sock *sk, int level, int optname,
v.val = READ_ONCE(sk->sk_mark);
break;
+ case SO_RX_IFINDEX:
+ v.val = READ_ONCE(sk->sk_rx_dst_ifindex);
+ break;
+
case SO_RCVMARK:
v.val = sock_flag(sk, SOCK_RCVMARK);
break;
--
2.47.0.105.g07ac214952-goog
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH net-next] net: define and implement new SOL_SOCKET SO_RX_IFINDEX option
2024-10-24 15:41 [PATCH net-next] net: define and implement new SOL_SOCKET SO_RX_IFINDEX option Maciej Żenczykowski
@ 2024-10-24 15:44 ` Maciej Żenczykowski
2024-10-25 14:44 ` Willem de Bruijn
0 siblings, 1 reply; 3+ messages in thread
From: Maciej Żenczykowski @ 2024-10-24 15:44 UTC (permalink / raw)
To: Maciej Żenczykowski
Cc: Linux Network Development Mailing List, David S . Miller,
Eric Dumazet, Jakub Kicinski, Paolo Abeni, Lorenzo Colitti
On Thu, Oct 24, 2024 at 5:41 PM Maciej Żenczykowski <maze@google.com> wrote:
>
> This is currently only implemented for TCP and is not
> guaranteed to return correct information for a multitude
> of reasons (including multipath reception), but there are
> scenarios where it is useful: in particular a strong host
> model where connections are only viable via a single interface,
> for example a VPN interface. One could for example choose
> to use this to SO_BINDTODEVICE.
>
> Test:
> // Python 2.7.18 (default, Jul 13 2022, 18:14:36)
> import socket
> SO_RX_IFINDEX=82
> s = socket.socket(socket.AF_INET6, socket.SOCK_STREAM, 0)
> c = socket.socket(socket.AF_INET6, socket.SOCK_STREAM, 0)
> s.bind(('::', 8888))
> s.listen(128)
> c.connect(('::', 8888))
> a = s.accept()
> print a # (<socket._socketobject object>, ('::1', 58144, 0, 0))
> p=a[0]
> p.getsockname() # ('::1', 8888, 0, 0)
> p.getpeername() # ('::1', 58144, 0, 0)
> c.getsockname() # ('::1', 58144, 0, 0)
> c.getpeername() # ('::1', 8888, 0, 0)
> p.getsockopt(socket.SOL_SOCKET, SO_RX_IFINDEX) # 1 (lo)
> c.getsockopt(socket.SOL_SOCKET, SO_RX_IFINDEX) # 0 (unknown)
> c.send(b'X') # 1
> p.recv(2) # 'X'
> p.getsockopt(socket.SOL_SOCKET, SO_RX_IFINDEX) # 1 (lo)
> c.getsockopt(socket.SOL_SOCKET, SO_RX_IFINDEX) # 0 (unknown)
> p.send(b'Z') # 1
> c.recv(2) # 'Z'
> p.getsockopt(socket.SOL_SOCKET, SO_RX_IFINDEX) # 1 (lo)
> c.getsockopt(socket.SOL_SOCKET, SO_RX_IFINDEX) # 1 (lo)
>
> Which shows we should possibly fix the 3-way handshake SYN-ACK
> to set sk->sk_rx_dst_ifindex.
>
> Cc: Lorenzo Colitti <lorenzo@google.com>
> Cc: Eric Dumazet <edumazet@google.com>
> Signed-off-by: Maciej Żenczykowski <maze@google.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 | 4 ++++
> 6 files changed, 14 insertions(+)
>
> diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h
> index 302507bf9b5d..5f139b095a49 100644
> --- a/arch/alpha/include/uapi/asm/socket.h
> +++ b/arch/alpha/include/uapi/asm/socket.h
> @@ -148,6 +148,8 @@
>
> #define SCM_TS_OPT_ID 81
>
> +#define SO_RX_IFINDEX 82
> +
> #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 d118d4731580..ff25d24b4dea 100644
> --- a/arch/mips/include/uapi/asm/socket.h
> +++ b/arch/mips/include/uapi/asm/socket.h
> @@ -159,6 +159,8 @@
>
> #define SCM_TS_OPT_ID 81
>
> +#define SO_RX_IFINDEX 82
> +
> #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 d268d69bfcd2..3f89c388e356 100644
> --- a/arch/parisc/include/uapi/asm/socket.h
> +++ b/arch/parisc/include/uapi/asm/socket.h
> @@ -140,6 +140,8 @@
>
> #define SCM_TS_OPT_ID 0x404C
>
> +#define SO_RX_IFINDEX 82
> +
> #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 113cd9f353e3..f1af74f5f1ad 100644
> --- a/arch/sparc/include/uapi/asm/socket.h
> +++ b/arch/sparc/include/uapi/asm/socket.h
> @@ -141,6 +141,8 @@
>
> #define SCM_TS_OPT_ID 0x005a
>
> +#define SO_RX_IFINDEX 0x005b
> +
> #if !defined(__KERNEL__)
>
>
> diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
> index deacfd6dd197..b16c69e22606 100644
> --- a/include/uapi/asm-generic/socket.h
> +++ b/include/uapi/asm-generic/socket.h
> @@ -143,6 +143,8 @@
>
> #define SCM_TS_OPT_ID 81
>
> +#define SO_RX_IFINDEX 82
> +
> #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 7f398bd07fb7..6c985413c21f 100644
> --- a/net/core/sock.c
> +++ b/net/core/sock.c
> @@ -1932,6 +1932,10 @@ int sk_getsockopt(struct sock *sk, int level, int optname,
> v.val = READ_ONCE(sk->sk_mark);
> break;
>
> + case SO_RX_IFINDEX:
> + v.val = READ_ONCE(sk->sk_rx_dst_ifindex);
> + break;
> +
> case SO_RCVMARK:
> v.val = sock_flag(sk, SOCK_RCVMARK);
> break;
> --
> 2.47.0.105.g07ac214952-goog
>
Note: I'm not sure if I did the right thing with parisc...
It has:
#define SO_DEVMEM_LINEAR 78
#define SCM_DEVMEM_LINEAR SO_DEVMEM_LINEAR
#define SO_DEVMEM_DMABUF 79
#define SCM_DEVMEM_DMABUF SO_DEVMEM_DMABUF
#define SO_DEVMEM_DONTNEED 80
which is weird...
--
Maciej Żenczykowski, Kernel Networking Developer @ Google
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH net-next] net: define and implement new SOL_SOCKET SO_RX_IFINDEX option
2024-10-24 15:44 ` Maciej Żenczykowski
@ 2024-10-25 14:44 ` Willem de Bruijn
0 siblings, 0 replies; 3+ messages in thread
From: Willem de Bruijn @ 2024-10-25 14:44 UTC (permalink / raw)
To: Maciej Żenczykowski, Maciej Żenczykowski
Cc: Linux Network Development Mailing List, David S . Miller,
Eric Dumazet, Jakub Kicinski, Paolo Abeni, Lorenzo Colitti
Maciej Żenczykowski wrote:
> On Thu, Oct 24, 2024 at 5:41 PM Maciej Żenczykowski <maze@google.com> wrote:
> >
> > This is currently only implemented for TCP and is not
> > guaranteed to return correct information for a multitude
> > of reasons (including multipath reception), but there are
> > scenarios where it is useful: in particular a strong host
> > model where connections are only viable via a single interface,
> > for example a VPN interface. One could for example choose
> > to use this to SO_BINDTODEVICE.
Fair to say that this is the equivalent of ipi_ifindex in IP_PKTINFO,
but for non datagram sockets where skb_iff cannot be read directly?
> >
> > Test:
> > // Python 2.7.18 (default, Jul 13 2022, 18:14:36)
> > import socket
> > SO_RX_IFINDEX=82
> > s = socket.socket(socket.AF_INET6, socket.SOCK_STREAM, 0)
> > c = socket.socket(socket.AF_INET6, socket.SOCK_STREAM, 0)
> > s.bind(('::', 8888))
> > s.listen(128)
> > c.connect(('::', 8888))
> > a = s.accept()
> > print a # (<socket._socketobject object>, ('::1', 58144, 0, 0))
> > p=a[0]
> > p.getsockname() # ('::1', 8888, 0, 0)
> > p.getpeername() # ('::1', 58144, 0, 0)
> > c.getsockname() # ('::1', 58144, 0, 0)
> > c.getpeername() # ('::1', 8888, 0, 0)
> > p.getsockopt(socket.SOL_SOCKET, SO_RX_IFINDEX) # 1 (lo)
> > c.getsockopt(socket.SOL_SOCKET, SO_RX_IFINDEX) # 0 (unknown)
> > c.send(b'X') # 1
> > p.recv(2) # 'X'
> > p.getsockopt(socket.SOL_SOCKET, SO_RX_IFINDEX) # 1 (lo)
> > c.getsockopt(socket.SOL_SOCKET, SO_RX_IFINDEX) # 0 (unknown)
> > p.send(b'Z') # 1
> > c.recv(2) # 'Z'
> > p.getsockopt(socket.SOL_SOCKET, SO_RX_IFINDEX) # 1 (lo)
> > c.getsockopt(socket.SOL_SOCKET, SO_RX_IFINDEX) # 1 (lo)
> >
> > Which shows we should possibly fix the 3-way handshake SYN-ACK
> > to set sk->sk_rx_dst_ifindex.
> >
> > Cc: Lorenzo Colitti <lorenzo@google.com>
> > Cc: Eric Dumazet <edumazet@google.com>
> > Signed-off-by: Maciej Żenczykowski <maze@google.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 | 4 ++++
> > 6 files changed, 14 insertions(+)
> >
> > diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h
> > index 302507bf9b5d..5f139b095a49 100644
> > --- a/arch/alpha/include/uapi/asm/socket.h
> > +++ b/arch/alpha/include/uapi/asm/socket.h
> > @@ -148,6 +148,8 @@
> >
> > #define SCM_TS_OPT_ID 81
> >
> > +#define SO_RX_IFINDEX 82
> > +
> > #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 d118d4731580..ff25d24b4dea 100644
> > --- a/arch/mips/include/uapi/asm/socket.h
> > +++ b/arch/mips/include/uapi/asm/socket.h
> > @@ -159,6 +159,8 @@
> >
> > #define SCM_TS_OPT_ID 81
> >
> > +#define SO_RX_IFINDEX 82
> > +
> > #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 d268d69bfcd2..3f89c388e356 100644
> > --- a/arch/parisc/include/uapi/asm/socket.h
> > +++ b/arch/parisc/include/uapi/asm/socket.h
> > @@ -140,6 +140,8 @@
> >
> > #define SCM_TS_OPT_ID 0x404C
> >
> > +#define SO_RX_IFINDEX 82
> > +
> > #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 113cd9f353e3..f1af74f5f1ad 100644
> > --- a/arch/sparc/include/uapi/asm/socket.h
> > +++ b/arch/sparc/include/uapi/asm/socket.h
> > @@ -141,6 +141,8 @@
> >
> > #define SCM_TS_OPT_ID 0x005a
> >
> > +#define SO_RX_IFINDEX 0x005b
> > +
> > #if !defined(__KERNEL__)
> >
> >
> > diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
> > index deacfd6dd197..b16c69e22606 100644
> > --- a/include/uapi/asm-generic/socket.h
> > +++ b/include/uapi/asm-generic/socket.h
> > @@ -143,6 +143,8 @@
> >
> > #define SCM_TS_OPT_ID 81
> >
> > +#define SO_RX_IFINDEX 82
> > +
> > #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 7f398bd07fb7..6c985413c21f 100644
> > --- a/net/core/sock.c
> > +++ b/net/core/sock.c
> > @@ -1932,6 +1932,10 @@ int sk_getsockopt(struct sock *sk, int level, int optname,
> > v.val = READ_ONCE(sk->sk_mark);
> > break;
> >
> > + case SO_RX_IFINDEX:
> > + v.val = READ_ONCE(sk->sk_rx_dst_ifindex);
> > + break;
> > +
If it is limited to TCP, return error in other cases.
So that we can extend it later with well defined behavior.
> > case SO_RCVMARK:
> > v.val = sock_flag(sk, SOCK_RCVMARK);
> > break;
> > --
> > 2.47.0.105.g07ac214952-goog
> >
>
> Note: I'm not sure if I did the right thing with parisc...
> It has:
> #define SO_DEVMEM_LINEAR 78
> #define SCM_DEVMEM_LINEAR SO_DEVMEM_LINEAR
> #define SO_DEVMEM_DMABUF 79
> #define SCM_DEVMEM_DMABUF SO_DEVMEM_DMABUF
> #define SO_DEVMEM_DONTNEED 80
> which is weird...
This is a common pattern.
To define separate SCM constants for cmsg fields, even though they
have the same constant as their [gs]etsockopt counterparts.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2024-10-25 14:44 ` Willem de Bruijn
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