From 0cac0cf4a7b60c889221c856087db5861a6bc5b7 Mon Sep 17 00:00:00 2001
From: Mark Stapp <mjs@voltanet.io>
Date: Wed, 1 Jul 2020 15:55:16 -0400
Subject: [PATCH] lib: add nexthop_str2backup

Add an api to convert an input list into an array of backup
nexthop indexes; useful for cli input.

Signed-off-by: Mark Stapp <mjs@voltanet.io>
---
 lib/nexthop.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 lib/nexthop.h |  9 ++++++++
 2 files changed, 71 insertions(+), 1 deletion(-)

diff --git a/lib/nexthop.c b/lib/nexthop.c
index 3f5308bc27..891ee64d64 100644
--- a/lib/nexthop.c
+++ b/lib/nexthop.c
@@ -658,7 +658,7 @@ void nexthop_copy(struct nexthop *copy, const struct nexthop *nexthop,
 	nexthop_copy_no_recurse(copy, nexthop, rparent);
 
 	/* Bit of a special case here, we need to handle the case
-	 * of a nexthop resolving to agroup. Hence, we need to
+	 * of a nexthop resolving to a group. Hence, we need to
 	 * use a nexthop_group API.
 	 */
 	if (CHECK_FLAG(copy->flags, NEXTHOP_FLAG_RECURSIVE))
@@ -683,6 +683,67 @@ struct nexthop *nexthop_dup(const struct nexthop *nexthop,
 	return new;
 }
 
+/*
+ * Parse one or more backup index values, as comma-separated numbers,
+ * into caller's array of uint8_ts. The array must be NEXTHOP_MAX_BACKUPS
+ * in size. Mails back the number of values converted, and returns 0 on
+ * success, <0 if an error in parsing.
+ */
+int nexthop_str2backups(const char *str, int *num_backups,
+			uint8_t *backups)
+{
+	char *ostr;			  /* copy of string (start) */
+	char *lstr;			  /* working copy of string */
+	char *nump;			  /* pointer to next segment */
+	char *endp;			  /* end pointer */
+	int i, ret;
+	uint8_t tmp[NEXTHOP_MAX_BACKUPS];
+	uint32_t lval;
+
+	/* Copy incoming string; the parse is destructive */
+	lstr = ostr = XSTRDUP(MTYPE_TMP, str);
+	*num_backups = 0;
+	ret = 0;
+
+	for (i = 0; i < NEXTHOP_MAX_BACKUPS && lstr; i++) {
+		nump = strsep(&lstr, ",");
+		lval = strtoul(nump, &endp, 10);
+
+		/* Format check */
+		if (*endp != '\0') {
+			ret = -1;
+			break;
+		}
+
+		/* Empty value */
+		if (endp == nump) {
+			ret = -1;
+			break;
+		}
+
+		/* Limit to one octet */
+		if (lval > 255) {
+			ret = -1;
+			break;
+		}
+
+		tmp[i] = lval;
+	}
+
+	/* Excess values */
+	if (ret == 0 && i == NEXTHOP_MAX_BACKUPS && lstr)
+		ret = -1;
+
+	if (ret == 0) {
+		*num_backups = i;
+		memcpy(backups, tmp, i);
+	}
+
+	XFREE(MTYPE_TMP, ostr);
+
+	return ret;
+}
+
 /*
  * nexthop printing variants:
  *	%pNHvv
diff --git a/lib/nexthop.h b/lib/nexthop.h
index e40c27d873..eaf67e6af1 100644
--- a/lib/nexthop.h
+++ b/lib/nexthop.h
@@ -235,6 +235,15 @@ extern struct nexthop *nexthop_dup(const struct nexthop *nexthop,
 extern struct nexthop *nexthop_dup_no_recurse(const struct nexthop *nexthop,
 					      struct nexthop *rparent);
 
+/*
+ * Parse one or more backup index values, as comma-separated numbers,
+ * into caller's array of uint8_ts. The array must be NEXTHOP_MAX_BACKUPS
+ * in size. Mails back the number of values converted, and returns 0 on
+ * success, <0 if an error in parsing.
+ */
+int nexthop_str2backups(const char *str, int *num_backups,
+			uint8_t *backups);
+
 #ifdef _FRR_ATTRIBUTE_PRINTFRR
 #pragma FRR printfrr_ext "%pNH"  (struct nexthop *)
 #endif
-- 
2.39.5