[PATCH net-next 13/14] net/smc: introduce CLC first contact extension

Karsten Graul
2020-09-26T10:44:55Z

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>
---
net/smc/af_smc.c | 29 +++++++++++++++++++++++++++++
net/smc/smc.h | 1 +
net/smc/smc_clc.c | 42 +++++++++++++++++++++++++++++++++++++-----
net/smc/smc_clc.h | 18 ++++++++++++++++++
net/smc/smc_core.c | 1 +
net/smc/smc_core.h | 5 +++++
6 files changed, 91 insertions(+), 5 deletions(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index da282a860cfb..3007f9c36d2c 100644
--- a/net/smc/af_smc.c
+++ b/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)
diff --git a/net/smc/smc.h b/net/smc/smc.h
index a1e480a3ec43..d65e15f0c944 100644
--- a/net/smc/smc.h
+++ b/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;
diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
index a2eb59dbcdb0..6762291b3940 100644
--- a/net/smc/smc_clc.c
+++ b/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)));
+}
diff --git a/net/smc/smc_clc.h b/net/smc/smc_clc.h
index 926b86cce68f..92179d955f59 100644
--- a/net/smc/smc_clc.h
+++ b/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
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index c52acb6fe6c9..f1dbb5025c0b 100644
--- a/net/smc/smc_core.c
+++ b/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 {
diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
index 35e38dd26cbf..f1e867ce2e63 100644
--- a/net/smc/smc_core.h
+++ b/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;
--
2.17.1