lib: add `s` option to `pI4`/`pI6`/`pIA` printfrr

Adding an `s` after these printfrr specifiers replaces 0.0.0.0 / :: in
the output with a star (`*`).  This is primarily intended for use with
multicast, e.g. to print `(*,G)`.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>

1 files changed, 46 insertions, 0 deletions

diff --git a/lib/prefix.c b/lib/prefix.c
index d3e8a612e..4e9d41836 100644
--- a/lib/prefix.c
+++ b/lib/prefix.c
@@ -1374,10 +1374,36 @@ static ssize_t printfrr_ia(struct fbuf *buf, struct printfrr_eargs *ea,
 {
 	const struct ipaddr *ipa = ptr;
 	char cbuf[INET6_ADDRSTRLEN];
+	bool use_star = false;
+
+	if (ea->fmt[0] == 's') {
+		use_star = true;
+		ea->fmt++;
+	}
 
 	if (!ipa)
 		return bputs(buf, "(null)");
 
+	if (use_star) {
+		struct in_addr zero4 = {};
+		struct in6_addr zero6 = {};
+
+		switch (ipa->ipa_type) {
+		case IPADDR_V4:
+			if (!memcmp(&ipa->ip.addr, &zero4, sizeof(zero4)))
+				return bputch(buf, '*');
+			break;
+
+		case IPADDR_V6:
+			if (!memcmp(&ipa->ip.addr, &zero6, sizeof(zero6)))
+				return bputch(buf, '*');
+			break;
+
+		default:
+			break;
+		}
+	}
+
 	ipaddr2str(ipa, cbuf, sizeof(cbuf));
 	return bputs(buf, cbuf);
 }
@@ -1387,10 +1413,20 @@ static ssize_t printfrr_i4(struct fbuf *buf, struct printfrr_eargs *ea,
 			   const void *ptr)
 {
 	char cbuf[INET_ADDRSTRLEN];
+	bool use_star = false;
+	struct in_addr zero = {};
+
+	if (ea->fmt[0] == 's') {
+		use_star = true;
+		ea->fmt++;
+	}
 
 	if (!ptr)
 		return bputs(buf, "(null)");
 
+	if (use_star && !memcmp(ptr, &zero, sizeof(zero)))
+		return bputch(buf, '*');
+
 	inet_ntop(AF_INET, ptr, cbuf, sizeof(cbuf));
 	return bputs(buf, cbuf);
 }
@@ -1400,10 +1436,20 @@ static ssize_t printfrr_i6(struct fbuf *buf, struct printfrr_eargs *ea,
 			   const void *ptr)
 {
 	char cbuf[INET6_ADDRSTRLEN];
+	bool use_star = false;
+	struct in6_addr zero = {};
+
+	if (ea->fmt[0] == 's') {
+		use_star = true;
+		ea->fmt++;
+	}
 
 	if (!ptr)
 		return bputs(buf, "(null)");
 
+	if (use_star && !memcmp(ptr, &zero, sizeof(zero)))
+		return bputch(buf, '*');
+
 	inet_ntop(AF_INET6, ptr, cbuf, sizeof(cbuf));
 	return bputs(buf, cbuf);
 }