nvme-fc: revise TRADDR parsing

The FC-NVME spec hasn't locked down on the format string for TRADDR.
Currently the spec is lobbying for "nn-<16hexdigits>:pn-<16hexdigits>"
where the wwn's are hex values but not prefixed by 0x.

Most implementations so far expect a string format of
"nn-0x<16hexdigits>:pn-0x<16hexdigits>" to be used. The transport
uses the match_u64 parser which requires a leading 0x prefix to set
the base properly. If it's not there, a match will either fail or return
a base 10 value.

The resolution in T11 is pushing out. Therefore, to fix things now and
to cover any eventuality and any implementations already in the field,
this patch adds support for both formats.

The change consists of replacing the token matching routine with a
routine that validates the fixed string format, and then builds
a local copy of the hex name with a 0x prefix before calling
the system parser.

Note: the same parser routine exists in both the initiator and target
transports. Given this is about the only "shared" item, we chose to
replicate rather than create an interdendency on some shared code.

Signed-off-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

1 files changed, 53 insertions, 48 deletions

diff --git a/drivers/nvme/target/fc.c b/drivers/nvme/target/fc.c
index d5801c150b1c..31ca55dfcb1d 100644
--- a/drivers/nvme/target/fc.c
+++ b/drivers/nvme/target/fc.c
@@ -2293,66 +2293,70 @@ nvmet_fc_rcv_fcp_abort(struct nvmet_fc_target_port *target_port,
 }
 EXPORT_SYMBOL_GPL(nvmet_fc_rcv_fcp_abort);
 
-enum {
-	FCT_TRADDR_ERR		= 0,
-	FCT_TRADDR_WWNN		= 1 << 0,
-	FCT_TRADDR_WWPN		= 1 << 1,
-};
 
 struct nvmet_fc_traddr {
 	u64	nn;
 	u64	pn;
 };
 
-static const match_table_t traddr_opt_tokens = {
-	{ FCT_TRADDR_WWNN,	"nn-%s"		},
-	{ FCT_TRADDR_WWPN,	"pn-%s"		},
-	{ FCT_TRADDR_ERR,	NULL		}
-};
-
 static int
-nvmet_fc_parse_traddr(struct nvmet_fc_traddr *traddr, char *buf)
+__nvme_fc_parse_u64(substring_t *sstr, u64 *val)
 {
-	substring_t args[MAX_OPT_ARGS];
-	char *options, *o, *p;
-	int token, ret = 0;
 	u64 token64;
 
-	options = o = kstrdup(buf, GFP_KERNEL);
-	if (!options)
-		return -ENOMEM;
+	if (match_u64(sstr, &token64))
+		return -EINVAL;
+	*val = token64;
 
-	while ((p = strsep(&o, ":\n")) != NULL) {
-		if (!*p)
-			continue;
+	return 0;
+}
 
-		token = match_token(p, traddr_opt_tokens, args);
-		switch (token) {
-		case FCT_TRADDR_WWNN:
-			if (match_u64(args, &token64)) {
-				ret = -EINVAL;
-				goto out;
-			}
-			traddr->nn = token64;
-			break;
-		case FCT_TRADDR_WWPN:
-			if (match_u64(args, &token64)) {
-				ret = -EINVAL;
-				goto out;
-			}
-			traddr->pn = token64;
-			break;
-		default:
-			pr_warn("unknown traddr token or missing value '%s'\n",
-					p);
-			ret = -EINVAL;
-			goto out;
-		}
-	}
+/*
+ * This routine validates and extracts the WWN's from the TRADDR string.
+ * As kernel parsers need the 0x to determine number base, universally
+ * build string to parse with 0x prefix before parsing name strings.
+ */
+static int
+nvme_fc_parse_traddr(struct nvmet_fc_traddr *traddr, char *buf, size_t blen)
+{
+	char name[2 + NVME_FC_TRADDR_HEXNAMELEN + 1];
+	substring_t wwn = { name, &name[sizeof(name)-1] };
+	int nnoffset, pnoffset;
+
+	/* validate it string one of the 2 allowed formats */
+	if (strnlen(buf, blen) == NVME_FC_TRADDR_MAXLENGTH &&
+			!strncmp(buf, "nn-0x", NVME_FC_TRADDR_OXNNLEN) &&
+			!strncmp(&buf[NVME_FC_TRADDR_MAX_PN_OFFSET],
+				"pn-0x", NVME_FC_TRADDR_OXNNLEN)) {
+		nnoffset = NVME_FC_TRADDR_OXNNLEN;
+		pnoffset = NVME_FC_TRADDR_MAX_PN_OFFSET +
+						NVME_FC_TRADDR_OXNNLEN;
+	} else if ((strnlen(buf, blen) == NVME_FC_TRADDR_MINLENGTH &&
+			!strncmp(buf, "nn-", NVME_FC_TRADDR_NNLEN) &&
+			!strncmp(&buf[NVME_FC_TRADDR_MIN_PN_OFFSET],
+				"pn-", NVME_FC_TRADDR_NNLEN))) {
+		nnoffset = NVME_FC_TRADDR_NNLEN;
+		pnoffset = NVME_FC_TRADDR_MIN_PN_OFFSET + NVME_FC_TRADDR_NNLEN;
+	} else
+		goto out_einval;
+
+	name[0] = '0';
+	name[1] = 'x';
+	name[2 + NVME_FC_TRADDR_HEXNAMELEN] = 0;
+
+	memcpy(&name[2], &buf[nnoffset], NVME_FC_TRADDR_HEXNAMELEN);
+	if (__nvme_fc_parse_u64(&wwn, &traddr->nn))
+		goto out_einval;
+
+	memcpy(&name[2], &buf[pnoffset], NVME_FC_TRADDR_HEXNAMELEN);
+	if (__nvme_fc_parse_u64(&wwn, &traddr->pn))
+		goto out_einval;
 
-out:
-	kfree(options);
-	return ret;
+	return 0;
+
+out_einval:
+	pr_warn("%s: bad traddr string\n", __func__);
+	return -EINVAL;
 }
 
 static int
@@ -2370,7 +2374,8 @@ nvmet_fc_add_port(struct nvmet_port *port)
 
 	/* map the traddr address info to a target port */
 
-	ret = nvmet_fc_parse_traddr(&traddr, port->disc_addr.traddr);
+	ret = nvme_fc_parse_traddr(&traddr, port->disc_addr.traddr,
+			sizeof(port->disc_addr.traddr));
 	if (ret)
 		return ret;