libceph: introduce connection modes and ms_mode option

msgr2 supports two connection modes: crc (plain) and secure (on-wire
encryption). Connection mode is picked by server based on input from
client.

Introduce ms_mode option:

ms_mode=legacy - msgr1 (default)
ms_mode=crc - crc mode, if denied fail
ms_mode=secure - secure mode, if denied fail
ms_mode=prefer-crc - crc mode, if denied agree to secure mode
ms_mode=prefer-secure - secure mode, if denied agree to crc mode

ms_mode affects all connections, we don't separate connections to mons
like it's done in userspace with ms_client_mode vs ms_mon_client_mode.

For now the default is legacy, to be flipped to prefer-crc after some
time.

Signed-off-by: Ilya Dryomov <[e-mail]>

include/linux/ceph/auth.h

···
 	const struct ceph_crypto_key *key;     /* our secret key */
 	unsigned want_keys;     /* which services we want */
 
+	int preferred_mode;	/* CEPH_CON_MODE_* */
+	int fallback_mode;	/* ditto */
+
 	struct mutex mutex;
 };
 
-extern struct ceph_auth_client *ceph_auth_init(const char *name,
-					       const struct ceph_crypto_key *key);
+struct ceph_auth_client *ceph_auth_init(const char *name,
+					const struct ceph_crypto_key *key,
+					const int *con_modes);
 extern void ceph_auth_destroy(struct ceph_auth_client *ac);
 
 extern void ceph_auth_reset(struct ceph_auth_client *ac);

include/linux/ceph/ceph_fs.h

···
 #define CEPH_AUTH_NONE	 	0x1
 #define CEPH_AUTH_CEPHX	 	0x2
 
+/* msgr2 protocol modes */
+#define CEPH_CON_MODE_UNKNOWN	0x0
+#define CEPH_CON_MODE_CRC	0x1
+#define CEPH_CON_MODE_SECURE	0x2
+
 #define CEPH_AUTH_UID_DEFAULT ((__u64) -1)
 
 const char *ceph_auth_proto_name(int proto);
+const char *ceph_con_mode_name(int mode);
 
 /*********************************************
  * message layer

include/linux/ceph/libceph.h

···
 	unsigned long osd_keepalive_timeout;	/* jiffies */
 	unsigned long osd_request_timeout;	/* jiffies */
 	u32 read_from_replica;  /* CEPH_OSD_FLAG_BALANCE/LOCALIZE_READS */
+	int con_modes[2];  /* CEPH_CON_MODE_* */
 
 	/*
 	 * any type that can't be simply compared or doesn't need

net/ceph/auth.c

···
 /*
  * setup, teardown.
  */
-struct ceph_auth_client *ceph_auth_init(const char *name, const struct ceph_crypto_key *key)
+struct ceph_auth_client *ceph_auth_init(const char *name,
+					const struct ceph_crypto_key *key,
+					const int *con_modes)
 {
 	struct ceph_auth_client *ac;
 	int ret;
-
-	dout("auth_init name '%s'\n", name);
 
 	ret = -ENOMEM;
 	ac = kzalloc(sizeof(*ac), GFP_NOFS);
···
 		ac->name = name;
 	else
 		ac->name = CEPH_AUTH_NAME_DEFAULT;
-	dout("auth_init name %s\n", ac->name);
 	ac->key = key;
+	ac->preferred_mode = con_modes[0];
+	ac->fallback_mode = con_modes[1];
+
+	dout("%s name '%s' preferred_mode %d fallback_mode %d\n", __func__,
+	     ac->name, ac->preferred_mode, ac->fallback_mode);
 	return ac;
 
 out:

net/ceph/ceph_common.c

···
 	Opt_ip,
 	Opt_crush_location,
 	Opt_read_from_replica,
+	Opt_ms_mode,
 	/* string args above */
 	Opt_share,
 	Opt_crc,
···
 	{}
 };
 
+enum ceph_ms_mode {
+	Opt_ms_mode_legacy,
+	Opt_ms_mode_crc,
+	Opt_ms_mode_secure,
+	Opt_ms_mode_prefer_crc,
+	Opt_ms_mode_prefer_secure
+};
+
+static const struct constant_table ceph_param_ms_mode[] = {
+	{"legacy",		Opt_ms_mode_legacy},
+	{"crc",			Opt_ms_mode_crc},
+	{"secure",		Opt_ms_mode_secure},
+	{"prefer-crc",		Opt_ms_mode_prefer_crc},
+	{"prefer-secure",	Opt_ms_mode_prefer_secure},
+	{}
+};
+
 static const struct fs_parameter_spec ceph_parameters[] = {
 	fsparam_flag	("abort_on_full",		Opt_abort_on_full),
 	fsparam_flag_no ("cephx_require_signatures",	Opt_cephx_require_signatures),
···
 			 fs_param_deprecated, NULL),
 	fsparam_enum	("read_from_replica",		Opt_read_from_replica,
 			 ceph_param_read_from_replica),
+	fsparam_enum	("ms_mode",			Opt_ms_mode,
+			 ceph_param_ms_mode),
 	fsparam_string	("secret",			Opt_secret),
 	fsparam_flag_no ("share",			Opt_share),
 	fsparam_flag_no ("tcp_nodelay",			Opt_tcp_nodelay),
···
 	opt->osd_idle_ttl = CEPH_OSD_IDLE_TTL_DEFAULT;
 	opt->osd_request_timeout = CEPH_OSD_REQUEST_TIMEOUT_DEFAULT;
 	opt->read_from_replica = CEPH_READ_FROM_REPLICA_DEFAULT;
+	opt->con_modes[0] = CEPH_CON_MODE_UNKNOWN;
+	opt->con_modes[1] = CEPH_CON_MODE_UNKNOWN;
 	return opt;
 }
 EXPORT_SYMBOL(ceph_alloc_options);
···
 			BUG();
 		}
 		break;
+	case Opt_ms_mode:
+		switch (result.uint_32) {
+		case Opt_ms_mode_legacy:
+			opt->con_modes[0] = CEPH_CON_MODE_UNKNOWN;
+			opt->con_modes[1] = CEPH_CON_MODE_UNKNOWN;
+			break;
+		case Opt_ms_mode_crc:
+			opt->con_modes[0] = CEPH_CON_MODE_CRC;
+			opt->con_modes[1] = CEPH_CON_MODE_UNKNOWN;
+			break;
+		case Opt_ms_mode_secure:
+			opt->con_modes[0] = CEPH_CON_MODE_SECURE;
+			opt->con_modes[1] = CEPH_CON_MODE_UNKNOWN;
+			break;
+		case Opt_ms_mode_prefer_crc:
+			opt->con_modes[0] = CEPH_CON_MODE_CRC;
+			opt->con_modes[1] = CEPH_CON_MODE_SECURE;
+			break;
+		case Opt_ms_mode_prefer_secure:
+			opt->con_modes[0] = CEPH_CON_MODE_SECURE;
+			opt->con_modes[1] = CEPH_CON_MODE_CRC;
+			break;
+		default:
+			BUG();
+		}
+		break;
 
 	case Opt_osdtimeout:
 		warn_plog(&log, "Ignoring osdtimeout");
···
 		seq_puts(m, "read_from_replica=balance,");
 	} else if (opt->read_from_replica == CEPH_OSD_FLAG_LOCALIZE_READS) {
 		seq_puts(m, "read_from_replica=localize,");
+	}
+	if (opt->con_modes[0] != CEPH_CON_MODE_UNKNOWN) {
+		if (opt->con_modes[0] == CEPH_CON_MODE_CRC &&
+		    opt->con_modes[1] == CEPH_CON_MODE_UNKNOWN) {
+			seq_puts(m, "ms_mode=crc,");
+		} else if (opt->con_modes[0] == CEPH_CON_MODE_SECURE &&
+			   opt->con_modes[1] == CEPH_CON_MODE_UNKNOWN) {
+			seq_puts(m, "ms_mode=secure,");
+		} else if (opt->con_modes[0] == CEPH_CON_MODE_CRC &&
+			   opt->con_modes[1] == CEPH_CON_MODE_SECURE) {
+			seq_puts(m, "ms_mode=prefer-crc,");
+		} else if (opt->con_modes[0] == CEPH_CON_MODE_SECURE &&
+			   opt->con_modes[1] == CEPH_CON_MODE_CRC) {
+			seq_puts(m, "ms_mode=prefer-secure,");
+		}
 	}
 
 	if (opt->flags & CEPH_OPT_FSID)

net/ceph/ceph_strings.c

···
 	}
 }
 
+const char *ceph_con_mode_name(int mode)
+{
+	switch (mode) {
+	case CEPH_CON_MODE_UNKNOWN:
+		return "unknown";
+	case CEPH_CON_MODE_CRC:
+		return "crc";
+	case CEPH_CON_MODE_SECURE:
+		return "secure";
+	default:
+		return "???";
+	}
+}
+
 const char *ceph_osd_op_name(int op)
 {
 	switch (op) {

net/ceph/mon_client.c

···
 
 	/* connection */
 	/* authentication */
-	monc->auth = ceph_auth_init(cl->options->name,
-				    cl->options->key);
+	monc->auth = ceph_auth_init(cl->options->name, cl->options->key,
+				    cl->options->con_modes);
 	if (IS_ERR(monc->auth)) {
 		err = PTR_ERR(monc->auth);
 		goto out_monmap;