Hi Martin,
Sorry to have been responding so late, I've been working on the
link_update you mentioned in last week,
I have completed the support and testing of the related functions of it.
and it is expected to be released in the
next few days.
As you mentioned, I do have much experience in kernel network
development, so I plan to resend the PATCH in the form of RFC.
I really hope to receive your suggestions in next serials. Thank you.😉
Best wishes.
D. Wythe
On 3/25/23 7:27 AM, Martin KaFai Lau wrote:
On 3/23/23 9:08 PM, D. Wythe wrote:
The latest design is that users can register a negotiator
implementation indexed by name, smc_sock can use bpf_setsockopt to
specify
whether a specific negotiation implementation is required via name.
If there are no settings, there will be no negotiators.
What do you think?
tbh, bpf_setsockopt is many steps away. It needs to begin with a
syscall setsockopt first. There is little reason it can only be done
with a bpf prog. and how does the user know which negotiator a smc
sock is using? Currently, ss can learn the tcp-cc of a sk.
~~~~~~~~
If this effort is serious, the code quality has to be much improved.
The obvious bug and unused variables make this set at most a RFC.
From the bpf perspective, it is ok-ish to start with a global
negotiator first and skip the setsockopt details for now. However, it
needs to be have a name. The new link_update
(https://lore.kernel.org/bpf/20230323032405.3735486-1-kuifeng@xxxxxxxx/)
has to work also. The struct_ops is rcu reader safe, so leverage it
whenever it can instead of the read/write lock. It is how struct_ops
work for tcp, so try to stay consistent as much as possible in the
networking stack.
In addition, I am very sorry that I have not issued my implementation
for such a long time, and I have encountered some problems with the
implementation because
the SMC needs to be built as kernel module, I have struggled with the
bpf_setsockopt implementation, and there are some new self-testes
that need to be written.
Regarding compiling as module,
+ifneq ($(CONFIG_SMC),)
+ifeq ($(CONFIG_BPF_SYSCALL),y)
+obj-y += smc/bpf_smc_struct_ops.o
+endif
struct_ops does not support module now. It is on the todo list. The
bpf_smc_struct_ops.o above can only be used when CONFIG_SMC=y.
Otherwise, the bpf_smc_struct_ops is always built in while most users
will never load the smc module.
