net/smc: add generic netlink support for system EID

With SMC-Dv2 users can configure if the static system EID should be used during CLC handshake, or if only user EIDs are allowed. Add generic netlink support to enable and disable the system EID, and to retrieve the system EID and its current enabled state. Signed-off-by: Karsten Graul <[email protected]> Reviewed-by: Guvenc Gulce <[email protected]> Signed-off-by: Guvenc Gulce <[email protected]> Signed-off-by: David S. Miller <[email protected]>
ambv · Sep 14, 2021 · 3c57214 · 3c57214
1 parent 11a26c5
commit 3c57214
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diff --git a/include/uapi/linux/smc.h b/include/uapi/linux/smc.h
@@ -56,6 +56,9 @@ enum {
 	SMC_NETLINK_ADD_UEID,
 	SMC_NETLINK_REMOVE_UEID,
 	SMC_NETLINK_FLUSH_UEID,
+	SMC_NETLINK_DUMP_SEID,
+	SMC_NETLINK_ENABLE_SEID,
+	SMC_NETLINK_DISABLE_SEID,
 };
 
 /* SMC_GENL_FAMILY top level attributes */
@@ -257,4 +260,13 @@ enum {
 	__SMC_NLA_EID_TABLE_MAX,
 	SMC_NLA_EID_TABLE_MAX = __SMC_NLA_EID_TABLE_MAX - 1
 };
+
+/* SMC_NETLINK_SEID attributes */
+enum {
+	SMC_NLA_SEID_UNSPEC,
+	SMC_NLA_SEID_ENTRY,	/* string */
+	SMC_NLA_SEID_ENABLED,	/* u8 */
+	__SMC_NLA_SEID_TABLE_MAX,
+	SMC_NLA_SEID_TABLE_MAX = __SMC_NLA_SEID_TABLE_MAX - 1
+};
 #endif /* _UAPI_LINUX_SMC_H */
diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
@@ -143,6 +143,10 @@ static int smc_clc_ueid_remove(char *ueid)
 			rc = 0;
 		}
 	}
+	if (!rc && !smc_clc_eid_table.ueid_cnt) {
+		smc_clc_eid_table.seid_enabled = 1;
+		rc = -EAGAIN;	/* indicate success and enabling of seid */
+	}
 	write_unlock(&smc_clc_eid_table.lock);
 	return rc;
 }
@@ -216,6 +220,64 @@ int smc_nl_dump_ueid(struct sk_buff *skb, struct netlink_callback *cb)
 	return skb->len;
 }
 
+int smc_nl_dump_seid(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct smc_nl_dmp_ctx *cb_ctx = smc_nl_dmp_ctx(cb);
+	char seid_str[SMC_MAX_EID_LEN + 1];
+	u8 seid_enabled;
+	void *hdr;
+	u8 *seid;
+
+	if (cb_ctx->pos[0])
+		return skb->len;
+
+	hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
+			  &smc_gen_nl_family, NLM_F_MULTI,
+			  SMC_NETLINK_DUMP_SEID);
+	if (!hdr)
+		return -ENOMEM;
+	if (!smc_ism_is_v2_capable())
+		goto end;
+
+	smc_ism_get_system_eid(&seid);
+	snprintf(seid_str, sizeof(seid_str), "%s", seid);
+	if (nla_put_string(skb, SMC_NLA_SEID_ENTRY, seid_str))
+		goto err;
+	read_lock(&smc_clc_eid_table.lock);
+	seid_enabled = smc_clc_eid_table.seid_enabled;
+	read_unlock(&smc_clc_eid_table.lock);
+	if (nla_put_u8(skb, SMC_NLA_SEID_ENABLED, seid_enabled))
+		goto err;
+end:
+	genlmsg_end(skb, hdr);
+	cb_ctx->pos[0]++;
+	return skb->len;
+err:
+	genlmsg_cancel(skb, hdr);
+	return -EMSGSIZE;
+}
+
+int smc_nl_enable_seid(struct sk_buff *skb, struct genl_info *info)
+{
+	write_lock(&smc_clc_eid_table.lock);
+	smc_clc_eid_table.seid_enabled = 1;
+	write_unlock(&smc_clc_eid_table.lock);
+	return 0;
+}
+
+int smc_nl_disable_seid(struct sk_buff *skb, struct genl_info *info)
+{
+	int rc = 0;
+
+	write_lock(&smc_clc_eid_table.lock);
+	if (!smc_clc_eid_table.ueid_cnt)
+		rc = -ENOENT;
+	else
+		smc_clc_eid_table.seid_enabled = 0;
+	write_unlock(&smc_clc_eid_table.lock);
+	return rc;
+}
+
 static bool _smc_clc_match_ueid(u8 *peer_ueid)
 {
 	struct smc_clc_eid_entry *tmp_ueid;

diff --git a/net/smc/smc_clc.h b/net/smc/smc_clc.h
@@ -347,5 +347,8 @@ int smc_nl_dump_ueid(struct sk_buff *skb, struct netlink_callback *cb);
 int smc_nl_add_ueid(struct sk_buff *skb, struct genl_info *info);
 int smc_nl_remove_ueid(struct sk_buff *skb, struct genl_info *info);
 int smc_nl_flush_ueid(struct sk_buff *skb, struct genl_info *info);
+int smc_nl_dump_seid(struct sk_buff *skb, struct netlink_callback *cb);
+int smc_nl_enable_seid(struct sk_buff *skb, struct genl_info *info);
+int smc_nl_disable_seid(struct sk_buff *skb, struct genl_info *info);
 
 #endif
diff --git a/net/smc/smc_netlink.c b/net/smc/smc_netlink.c
@@ -96,6 +96,21 @@ static const struct genl_ops smc_gen_nl_ops[] = {
 		.flags = GENL_ADMIN_PERM,
 		.doit = smc_nl_flush_ueid,
 	},
+	{
+		.cmd = SMC_NETLINK_DUMP_SEID,
+		/* can be retrieved by unprivileged users */
+		.dumpit = smc_nl_dump_seid,
+	},
+	{
+		.cmd = SMC_NETLINK_ENABLE_SEID,
+		.flags = GENL_ADMIN_PERM,
+		.doit = smc_nl_enable_seid,
+	},
+	{
+		.cmd = SMC_NETLINK_DISABLE_SEID,
+		.flags = GENL_ADMIN_PERM,
+		.doit = smc_nl_disable_seid,
+	},
 };
 
 static const struct nla_policy smc_gen_nl_policy[2] = {