net/smc: introduce CLC first contact extension

SMC Version 2 defines a first contact extension for CLC accept
and CLC confirm. This patch covers sending and receiving of the
CLC first contact extension.
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc/af_smc.c

@@ -26,6 +26,7 @@
 #include <linux/sched/signal.h>
 #include <linux/if_vlan.h>
 #include <linux/rcupdate_wait.h>
+#include <linux/ctype.h>
 
 #include <net/sock.h>
 #include <net/tcp.h>
@@ -448,6 +449,16 @@ static void smcr_conn_save_peer_info(struct smc_sock *smc,
 	smc->conn.tx_off = bufsize * (smc->conn.peer_rmbe_idx - 1);
 }
 
+static bool smc_isascii(char *hostname)
+{
+	int i;
+
+	for (i = 0; i < SMC_MAX_HOSTNAME_LEN; i++)
+		if (!isascii(hostname[i]))
+			return false;
+	return true;
+}
+
 static void smcd_conn_save_peer_info(struct smc_sock *smc,
 				     struct smc_clc_msg_accept_confirm *clc)
 {
@@ -459,6 +470,22 @@ static void smcd_conn_save_peer_info(struct smc_sock *smc,
 	smc->conn.peer_rmbe_size = bufsize - sizeof(struct smcd_cdc_msg);
 	atomic_set(&smc->conn.peer_rmbe_space, smc->conn.peer_rmbe_size);
 	smc->conn.tx_off = bufsize * smc->conn.peer_rmbe_idx;
+	if (clc->hdr.version > SMC_V1 &&
+	    (clc->hdr.typev2 & SMC_FIRST_CONTACT_MASK)) {
+		struct smc_clc_msg_accept_confirm_v2 *clc_v2 =
+			(struct smc_clc_msg_accept_confirm_v2 *)clc;
+		struct smc_clc_first_contact_ext *fce =
+			(struct smc_clc_first_contact_ext *)
+				(((u8 *)clc_v2) + sizeof(*clc_v2));
+
+		memcpy(smc->conn.lgr->negotiated_eid, clc_v2->eid,
+		       SMC_MAX_EID_LEN);
+		smc->conn.lgr->peer_os = fce->os_type;
+		smc->conn.lgr->peer_smc_release = fce->release;
+		if (smc_isascii(fce->hostname))
+			memcpy(smc->conn.lgr->peer_hostname, fce->hostname,
+			       SMC_MAX_HOSTNAME_LEN);
+	}
 }
 
 static void smc_conn_save_peer_info(struct smc_sock *smc,
@@ -662,6 +689,7 @@ static int smc_connect_ism_vlan_cleanup(struct smc_sock *smc,
 
 #define SMC_CLC_MAX_ACCEPT_LEN \
 	(sizeof(struct smc_clc_msg_accept_confirm_v2) + \
+	 sizeof(struct smc_clc_first_contact_ext) + \
 	 sizeof(struct smc_clc_msg_trail))
 
 /* CLC handshake during connect */
@@ -2422,6 +2450,7 @@ static int __init smc_init(void)
 		return rc;
 
 	smc_ism_init();
+	smc_clc_init();
 
 	rc = smc_pnet_init();
 	if (rc)

net/smc/smc.h

@@ -29,6 +29,7 @@
 					 * devices
 					 */
 
+#define SMC_MAX_HOSTNAME_LEN	32
 #define SMC_MAX_EID_LEN		32
 
 extern struct proto smc_proto;

net/smc/smc_clc.c

@@ -14,6 +14,8 @@
 #include <linux/inetdevice.h>
 #include <linux/if_ether.h>
 #include <linux/sched/signal.h>
+#include <linux/utsname.h>
+#include <linux/ctype.h>
 
 #include <net/addrconf.h>
 #include <net/sock.h>
@@ -35,6 +37,8 @@ static const char SMC_EYECATCHER[4] = {'\xe2', '\xd4', '\xc3', '\xd9'};
 /* eye catcher "SMCD" EBCDIC for CLC messages */
 static const char SMCD_EYECATCHER[4] = {'\xe2', '\xd4', '\xc3', '\xc4'};
 
+static u8 smc_hostname[SMC_MAX_HOSTNAME_LEN];
+
 /* check arriving CLC proposal */
 static bool smc_clc_msg_prop_valid(struct smc_clc_msg_proposal *pclc)
 {
@@ -92,12 +96,23 @@ smc_clc_msg_acc_conf_valid(struct smc_clc_msg_accept_confirm_v2 *clc_v2)
 			return false;
 	} else {
 		if (hdr->typev1 == SMC_TYPE_D &&
-		    ntohs(hdr->length) != SMCD_CLC_ACCEPT_CONFIRM_LEN_V2)
+		    ntohs(hdr->length) != SMCD_CLC_ACCEPT_CONFIRM_LEN_V2 &&
+		    (ntohs(hdr->length) != SMCD_CLC_ACCEPT_CONFIRM_LEN_V2 +
+				sizeof(struct smc_clc_first_contact_ext)))
 			return false;
 	}
 	return true;
 }
 
+static void smc_clc_fill_fce(struct smc_clc_first_contact_ext *fce, int *len)
+{
+	memset(fce, 0, sizeof(*fce));
+	fce->os_type = SMC_CLC_OS_LINUX;
+	fce->release = SMC_RELEASE;
+	memcpy(fce->hostname, smc_hostname, sizeof(smc_hostname));
+	(*len) += sizeof(*fce);
+}
+
 /* check if received message has a correct header length and contains valid
  * heading and trailing eyecatchers
  */
@@ -623,10 +638,11 @@ static int smc_clc_send_confirm_accept(struct smc_sock *smc,
 {
 	struct smc_connection *conn = &smc->conn;
 	struct smc_clc_msg_accept_confirm *clc;
+	struct smc_clc_first_contact_ext fce;
 	struct smc_clc_msg_trail trl;
-	struct kvec vec[2];
+	struct kvec vec[3];
 	struct msghdr msg;
-	int i;
+	int i, len;
 
 	/* send SMC Confirm CLC msg */
 	clc = (struct smc_clc_msg_accept_confirm *)clc_v2;
@@ -652,8 +668,10 @@ static int smc_clc_send_confirm_accept(struct smc_sock *smc,
 			smc_ism_get_system_eid(conn->lgr->smcd, &eid);
 			if (eid)
 				memcpy(clc_v2->eid, eid, SMC_MAX_EID_LEN);
-			clc_v2->hdr.length =
-					htons(SMCD_CLC_ACCEPT_CONFIRM_LEN_V2);
+			len = SMCD_CLC_ACCEPT_CONFIRM_LEN_V2;
+			if (first_contact)
+				smc_clc_fill_fce(&fce, &len);
+			clc_v2->hdr.length = htons(len);
 		}
 		memcpy(trl.eyecatcher, SMCD_EYECATCHER,
 		       sizeof(SMCD_EYECATCHER));
@@ -701,6 +719,10 @@ static int smc_clc_send_confirm_accept(struct smc_sock *smc,
 						SMCD_CLC_ACCEPT_CONFIRM_LEN :
 						SMCR_CLC_ACCEPT_CONFIRM_LEN) -
 				   sizeof(trl);
+	if (version > SMC_V1 && first_contact) {
+		vec[i].iov_base = &fce;
+		vec[i++].iov_len = sizeof(fce);
+	}
 	vec[i].iov_base = &trl;
 	vec[i++].iov_len = sizeof(trl);
 	return kernel_sendmsg(smc->clcsock, &msg, vec, 1,
@@ -748,3 +770,13 @@ int smc_clc_send_accept(struct smc_sock *new_smc, bool srv_first_contact,
 
 	return len > 0 ? 0 : len;
 }
+
+void __init smc_clc_init(void)
+{
+	struct new_utsname *u;
+
+	memset(smc_hostname, _S, sizeof(smc_hostname)); /* ASCII blanks */
+	u = utsname();
+	memcpy(smc_hostname, u->nodename,
+	       min_t(size_t, strlen(u->nodename), sizeof(smc_hostname)));
+}

net/smc/smc_clc.h

@@ -199,6 +199,23 @@ struct smcd_clc_msg_accept_confirm_common {	/* SMCD accept/confirm */
 	__be32 linkid;		/* Link identifier */
 } __packed;
 
+#define SMC_CLC_OS_ZOS		1
+#define SMC_CLC_OS_LINUX	2
+#define SMC_CLC_OS_AIX		3
+
+struct smc_clc_first_contact_ext {
+	u8 reserved1;
+#if defined(__BIG_ENDIAN_BITFIELD)
+	u8 os_type : 4,
+	   release : 4;
+#elif defined(__LITTLE_ENDIAN_BITFIELD)
+	u8 release : 4,
+	   os_type : 4;
+#endif
+	u8 reserved2[2];
+	u8 hostname[SMC_MAX_HOSTNAME_LEN];
+};
+
 struct smc_clc_msg_accept_confirm {	/* clc accept / confirm message */
 	struct smc_clc_msg_hdr hdr;
 	union {
@@ -304,5 +321,6 @@ int smc_clc_send_confirm(struct smc_sock *smc, bool clnt_first_contact,
 			 u8 version);
 int smc_clc_send_accept(struct smc_sock *smc, bool srv_first_contact,
 			u8 version);
+void smc_clc_init(void) __init;
 
 #endif

net/smc/smc_core.c

@@ -418,6 +418,7 @@ static int smc_lgr_create(struct smc_sock *smc, struct smc_init_info *ini)
 		lgr->smcd = ini->ism_dev[ini->ism_selected];
 		lgr_list = &ini->ism_dev[ini->ism_selected]->lgr_list;
 		lgr_lock = &lgr->smcd->lgr_lock;
+		lgr->smc_version = ini->smcd_version;
 		lgr->peer_shutdown = 0;
 		atomic_inc(&ini->ism_dev[ini->ism_selected]->lgr_cnt);
 	} else {

net/smc/smc_core.h

@@ -231,6 +231,11 @@ struct smc_link_group {
 	u8			freeing : 1;	/* lgr is being freed */
 
 	bool			is_smcd;	/* SMC-R or SMC-D */
+	u8			smc_version;
+	u8			negotiated_eid[SMC_MAX_EID_LEN];
+	u8			peer_os;	/* peer operating system */
+	u8			peer_smc_release;
+	u8			peer_hostname[SMC_MAX_HOSTNAME_LEN];
 	union {
 		struct { /* SMC-R */
 			enum smc_lgr_role	role;