On Wed, 5 Jun 2024, D. Wythe wrote:
From: "D. Wythe" <alibuda@xxxxxxxxxxxxxxxxx>
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.
Signed-off-by: D. Wythe <alibuda@xxxxxxxxxxxxxxxxx>
Tested-by: Niklas Schnelle <schnelle@xxxxxxxxxxxxx>
---
include/uapi/linux/in.h | 2 +
net/smc/Makefile | 2 +-
net/smc/af_smc.c | 16 ++++-
net/smc/smc_inet.c | 169 ++++++++++++++++++++++++++++++++++++++++++++++++
net/smc/smc_inet.h | 22 +++++++
5 files changed, 208 insertions(+), 3 deletions(-)
create mode 100644 net/smc/smc_inet.c
create mode 100644 net/smc/smc_inet.h
diff --git a/include/uapi/linux/in.h b/include/uapi/linux/in.h
index e682ab6..0c6322b 100644
--- a/include/uapi/linux/in.h
+++ b/include/uapi/linux/in.h
@@ -83,6 +83,8 @@ enum {
#define IPPROTO_RAW IPPROTO_RAW
IPPROTO_MPTCP = 262, /* Multipath TCP connection */
#define IPPROTO_MPTCP IPPROTO_MPTCP
+ IPPROTO_SMC = 263, /* Shared Memory Communications */
+#define IPPROTO_SMC IPPROTO_SMC
Hello,
It's not required to assign IPPROTO_MPTCP+1 as your new IPPROTO_SMC value.
Making IPPROTO_MAX larger does increase the size of the inet_diag_table.
Values from 256 to 261 are usable for IPPROTO_SMC without increasing
IPPROTO_MAX.
Just for background: When we added IPPROTO_MPTCP, we chose 262 because it
is IPPROTO_TCP+0x100. The IANA reserved protocol numbers are 8 bits wide
so we knew we would not conflict with any future additions, and in the
case of MPTCP is was convenient that truncating the proto value to 8 bits
would match IPPROTO_TCP.
- Mat
IPPROTO_MAX
};
