[PATCH net-next 2/2] net/smc: Introduce IPPROTO_SMC

D. Wythe
2024-05-10T04:12:28Z

From: "D. Wythe" <alibuda@linux.alibaba.com>

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@linux.alibaba.com>
---
include/uapi/linux/in.h | 2 +
net/smc/af_smc.c | 129 +++++++++++++++++++++++++++++++++++++++++++++++-
net/smc/inet_smc.h | 32 ++++++++++++
3 files changed, 162 insertions(+), 1 deletion(-)
create mode 100644 net/smc/inet_smc.h

diff --git a/include/uapi/linux/in.h b/include/uapi/linux/in.h
index e682ab6..74c12e33 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
IPPROTO_MAX
};
#endif
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 1f03724..b4557828 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -54,6 +54,7 @@
#include "smc_tracepoint.h"
#include "smc_sysctl.h"
#include "smc_loopback.h"
+#include "inet_smc.h"

static DEFINE_MUTEX(smc_server_lgr_pending); /* serialize link group
* creation on server
@@ -3402,6 +3403,16 @@ static int smc_create(struct net *net, struct socket *sock, int protocol,
.create = smc_create,
};

+int smc_inet_init_sock(struct sock *sk)
+{
+ struct net *net = sock_net(sk);
+
+ /* init common smc sock */
+ smc_sock_init(net, sk, IPPROTO_SMC);
+ /* create clcsock */
+ return __smc_create_clcsk(net, sk, sk->sk_family);
+}
+
static int smc_ulp_init(struct sock *sk)
{
struct socket *tcp = sk->sk_socket;
@@ -3460,6 +3471,90 @@ static void smc_ulp_clone(const struct request_sock *req, struct sock *newsk,
.clone = smc_ulp_clone,
};

+struct proto smc_inet_prot = {
+ .name = "INET_SMC",
+ .owner = THIS_MODULE,
+ .init = smc_inet_init_sock,
+ .hash = smc_hash_sk,
+ .unhash = smc_unhash_sk,
+ .release_cb = smc_release_cb,
+ .obj_size = sizeof(struct smc_sock),
+ .h.smc_hash = &smc_v4_hashinfo,
+ .slab_flags = SLAB_TYPESAFE_BY_RCU,
+};
+
+const struct proto_ops smc_inet_stream_ops = {
+ .family = PF_INET,
+ .owner = THIS_MODULE,
+ .release = smc_release,
+ .bind = smc_bind,
+ .connect = smc_connect,
+ .socketpair = sock_no_socketpair,
+ .accept = smc_accept,
+ .getname = smc_getname,
+ .poll = smc_poll,
+ .ioctl = smc_ioctl,
+ .listen = smc_listen,
+ .shutdown = smc_shutdown,
+ .setsockopt = smc_setsockopt,
+ .getsockopt = smc_getsockopt,
+ .sendmsg = smc_sendmsg,
+ .recvmsg = smc_recvmsg,
+ .mmap = sock_no_mmap,
+ .splice_read = smc_splice_read,
+};
+
+struct inet_protosw smc_inet_protosw = {
+ .type = SOCK_STREAM,
+ .protocol = IPPROTO_SMC,
+ .prot = &smc_inet_prot,
+ .ops = &smc_inet_stream_ops,
+ .flags = INET_PROTOSW_ICSK,
+};
+
+#if IS_ENABLED(CONFIG_IPV6)
+struct proto smc_inet6_prot = {
+ .name = "INET6_SMC",
+ .owner = THIS_MODULE,
+ .init = smc_inet_init_sock,
+ .hash = smc_hash_sk,
+ .unhash = smc_unhash_sk,
+ .release_cb = smc_release_cb,
+ .obj_size = sizeof(struct smc_sock),
+ .h.smc_hash = &smc_v6_hashinfo,
+ .slab_flags = SLAB_TYPESAFE_BY_RCU,
+};
+
+const struct proto_ops smc_inet6_stream_ops = {
+ .family = PF_INET6,
+ .owner = THIS_MODULE,
+ .release = smc_release,
+ .bind = smc_bind,
+ .connect = smc_connect,
+ .socketpair = sock_no_socketpair,
+ .accept = smc_accept,
+ .getname = smc_getname,
+ .poll = smc_poll,
+ .ioctl = smc_ioctl,
+ .listen = smc_listen,
+ .shutdown = smc_shutdown,
+ .setsockopt = smc_setsockopt,
+ .getsockopt = smc_getsockopt,
+ .sendmsg = smc_sendmsg,
+ .recvmsg = smc_recvmsg,
+ .mmap = sock_no_mmap,
+ .splice_read = smc_splice_read,
+};
+
+struct inet_protosw smc_inet6_protosw = {
+ .type = SOCK_STREAM,
+ .protocol = IPPROTO_SMC,
+ .prot = &smc_inet6_prot,
+ .ops = &smc_inet6_stream_ops,
+ .flags = INET_PROTOSW_ICSK,
+};
+#endif
+
unsigned int smc_net_id;

static __net_init int smc_net_init(struct net *net)
@@ -3595,9 +3690,28 @@ static int __init smc_init(void)
goto out_lo;
}

+ rc = proto_register(&smc_inet_prot, 1);
+ if (rc) {
+ pr_err("%s: proto_register smc_inet_prot fails with %d\n", __func__, rc);
+ goto out_ulp;
+ }
+ inet_register_protosw(&smc_inet_protosw);
+#if IS_ENABLED(CONFIG_IPV6)
+ rc = proto_register(&smc_inet6_prot, 1);
+ if (rc) {
+ pr_err("%s: proto_register smc_inet6_prot fails with %d\n", __func__, rc);
+ goto out_inet_prot;
+ }
+ inet6_register_protosw(&smc_inet6_protosw);
+#endif
+
static_branch_enable(&tcp_have_smc);
return 0;
-
+out_inet_prot:
+ inet_unregister_protosw(&smc_inet_protosw);
+ proto_unregister(&smc_inet_prot);
+out_ulp:
+ tcp_unregister_ulp(&smc_ulp_ops);
out_lo:
smc_loopback_exit();
out_ib:
@@ -3634,6 +3748,10 @@ static int __init smc_init(void)
static void __exit smc_exit(void)
{
static_branch_disable(&tcp_have_smc);
+ inet_unregister_protosw(&smc_inet_protosw);
+#if IS_ENABLED(CONFIG_IPV6)
+ inet6_unregister_protosw(&smc_inet6_protosw);
+#endif
tcp_unregister_ulp(&smc_ulp_ops);
sock_unregister(PF_SMC);
smc_core_exit();
@@ -3645,6 +3763,10 @@ static void __exit smc_exit(void)
destroy_workqueue(smc_hs_wq);
proto_unregister(&smc_proto6);
proto_unregister(&smc_proto);
+ proto_unregister(&smc_inet_prot);
+#if IS_ENABLED(CONFIG_IPV6)
+ proto_unregister(&smc_inet6_prot);
+#endif
smc_pnet_exit();
smc_nl_exit();
smc_clc_exit();
@@ -3661,4 +3783,9 @@ static void __exit smc_exit(void)
MODULE_LICENSE("GPL");
MODULE_ALIAS_NETPROTO(PF_SMC);
MODULE_ALIAS_TCP_ULP("smc");
+/* 263 for IPPROTO_SMC and 1 for SOCK_STREAM */
+MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 263, 1);
+#if IS_ENABLED(CONFIG_IPV6)
+MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 263, 1);
+#endif
MODULE_ALIAS_GENL_FAMILY(SMC_GENL_FAMILY_NAME);
diff --git a/net/smc/inet_smc.h b/net/smc/inet_smc.h
new file mode 100644
index 00000000..fcdcb61
--- /dev/null
+++ b/net/smc/inet_smc.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Shared Memory Communications over RDMA (SMC-R) and RoCE
+ *
+ * Definitions for the SMC module (socket related)
+
+ * Copyright IBM Corp. 2016
+ *
+ */
+#ifndef __INET_SMC
+#define __INET_SMC
+
+#include <net/protocol.h>
+#include <net/sock.h>
+#include <net/tcp.h>
+
+extern struct proto smc_inet_prot;
+extern const struct proto_ops smc_inet_stream_ops;
+extern struct inet_protosw smc_inet_protosw;
+
+#if IS_ENABLED(CONFIG_IPV6)
+#include <net/ipv6.h>
+/* MUST after net/tcp.h or warning */
+#include <net/transp_v6.h>
+extern struct proto smc_inet6_prot;
+extern const struct proto_ops smc_inet6_stream_ops;
+extern struct inet_protosw smc_inet6_protosw;
+#endif
+
+int smc_inet_init_sock(struct sock *sk);
+
+#endif // __INET_SMC
--
1.8.3.1