[net-next,v2,0/3] Introduce IPPROTO_SMC

Message

D. Wythe May 15, 2024, 6:41 a.m. UTC

From: "D. Wythe" <[e-mail]>

This patch allows to create smc socket via AF_INET,
similar to the following code,

/* create v4 smc sock */
v4 = socket(AF_INET, SOCK_STREAM, IPPROTO_SMC);

/* create v6 smc sock */
v6 = socket(AF_INET6, SOCK_STREAM, IPPROTO_SMC);

There are several reasons why we believe it is appropriate here:

1. For smc sockets, it actually use IPv4 (AF-INET) or IPv6 (AF-INET6)
address. There is no AF_SMC address at all.

2. Create smc socket in the AF_INET(6) path, which allows us to reuse
the infrastructure of AF_INET(6) path, such as common ebpf hooks.
Otherwise, smc have to implement it again in AF_SMC path. Such as:
  1. Replace IPPROTO_TCP with IPPROTO_SMC in the socket() syscall
     initiated by the user, without the use of LD-PRELOAD.
  2. Select whether immediate fallback is required based on peer's port/ip
     before connect().

A very significant result is that we can now use eBPF to implement smc_run
instead of LD_PRELOAD, who is completely ineffective in scenarios of static
linking.

Another potential value is that we are attempting to optimize the performance of
fallback socks, where merging socks is an important part, and it relies on the
creation of SMC sockets under the AF_INET path. (More information :
https://lore.kernel.org/netdev/[e-mail]/T/)

v1 -> v2 :

- Code formatting, mainly including alignment and annotation repair.
- move inet_smc proto ops to inet_smc.c, avoiding af_smc.c becoming too bulky.
- Fix the issue where refactoring affects the initialization order.
- Fix compile warning (unused out_inet_prot) while CONFIG_IPV6 was not set.

D. Wythe (3):
  net/smc: refatoring initialization of smc sock
  net/smc: expose smc proto operations
  net/smc: Introduce IPPROTO_SMC

 include/uapi/linux/in.h |   2 +
 net/smc/Makefile        |   2 +-
 net/smc/af_smc.c        | 183 ++++++++++++++++++++++++++++++------------------
 net/smc/inet_smc.c      | 107 ++++++++++++++++++++++++++++
 net/smc/inet_smc.h      |  32 +++++++++
 net/smc/smc.h           |  38 ++++++++++
 6 files changed, 294 insertions(+), 70 deletions(-)
 create mode 100644 net/smc/inet_smc.c
 create mode 100644 net/smc/inet_smc.h

Comments

Jakub Kicinski May 17, 2024, 7:19 p.m. UTC | #1

On Wed, 15 May 2024 14:41:43 +0800 D. Wythe wrote:
> This patch allows to create smc socket via AF_INET,
> similar to the following code,
> 
> /* create v4 smc sock */
> v4 = socket(AF_INET, SOCK_STREAM, IPPROTO_SMC);
> 
> /* create v6 smc sock */
> v6 = socket(AF_INET6, SOCK_STREAM, IPPROTO_SMC);

## Form letter - net-next-closed

The merge window for v6.10 has begun and we have already posted our pull
request. Therefore net-next is closed for new drivers, features, code
refactoring and optimizations. We are currently accepting bug fixes only.

Please repost when net-next reopens after May 26th.

RFC patches sent for review only are obviously welcome at any time.

See: https://www.kernel.org/doc/html/next/process/maintainer-netdev.html#development-cycle