[PATCH 10/12] conf: Use new parsing tools to handle -a option

[David Gibson <david@gibson.dropbear.id.au>]

The -a command line option can take either an address prefix, or a bare
address.  Current parsing of this is pretty awkward, using the special
purpose helper inany_prefix_pton().  With the new incremental parsing
helpers this can be done more naturally.  Rework it to use them.

This does requiring extending parse_inany() to parse_inany_() which also
reports the format of the address as parse, as opposed to the family of
the resulting address.  This is so that ::ffff:192.0.1.1/112 will be
correctly interpreted the same as 192.0.1.1/16, rather than the
nonsensical 192.0.0.1/112.

Cc: Jon Maloy <jmaloy@redhat.com>

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 Makefile |  1 -
 conf.c   | 63 +++++++++++++++++++++++++++++++++++---------------------
 inany.c  | 50 --------------------------------------------
 inany.h  |  2 --
 parse.c  | 17 ++++++++++++---
 parse.h  |  5 ++++-
 6 files changed, 58 insertions(+), 80 deletions(-)

diff --git a/Makefile b/Makefile
index e2b22ddf..5757aeff 100644
--- a/Makefile
+++ b/Makefile
@@ -223,7 +223,6 @@ passt-repair.cppcheck: $(PASST_REPAIR_SRCS) $(PASST_REPAIR_HEADERS) seccomp_repa
 pesto.cppcheck: BASE_CPPFLAGS += -DPESTO
 pesto.cppcheck: CPPCHECK_FLAGS += --suppress=unusedFunction:bitmap.c
 pesto.cppcheck: CPPCHECK_FLAGS += --suppress=unusedFunction:inany.h
-pesto.cppcheck: CPPCHECK_FLAGS += --suppress=unusedFunction:inany.c
 pesto.cppcheck: CPPCHECK_FLAGS += --suppress=unusedFunction:ip.h
 pesto.cppcheck: CPPCHECK_FLAGS += --suppress=unusedFunction:serialise.c
 pesto.cppcheck: CPPCHECK_FLAGS += --suppress=staticFunction:fwd_rule.c
diff --git a/conf.c b/conf.c
index 3614776c..ff7ca5c7 100644
--- a/conf.c
+++ b/conf.c
@@ -1176,43 +1176,60 @@ int conf_tap_fd(const char *arg)
  */
 static bool conf_addr(struct ctx *c, char *arg, uint8_t opt_n)
 {
+	unsigned long prefix_len;
+	const struct in_addr *a4;
 	union inany_addr addr;
+	sa_family_t parseaf;
 	const char *p = arg;
-	uint8_t prefix_len;
 	bool is_prefix;
 
-	is_prefix = inany_prefix_pton(arg, &addr, &prefix_len);
-
-	if (is_prefix && opt_n)
-		die("Redundant prefix length specification");
-
-	if (!is_prefix &&
-	    !(parse_inany(&p, &addr) && parse_eoi(p)))
-		die("Invalid address: %s", arg);
-
-	if (opt_n && inany_v4(&addr))
-		prefix_len = opt_n;
-	else if (!is_prefix)
-		prefix_len = inany_default_prefix_len(&addr);
+	if (!parse_inany_(&p, &addr, &parseaf))
+		goto bad;
+	a4 = inany_v4(&addr);
+
+	if ((is_prefix = parse_literal(&p, "/"))) {
+		/* Prefix length included in -a option */
+		if (!parse_unsigned(&p, 10, &prefix_len))
+			goto bad;
+		if (opt_n)
+			die("Redundant prefix length specification");
+		if (parseaf == AF_INET) {
+			if (prefix_len > 32)
+				goto bad_prefix;
+			prefix_len += 96;
+		} else if (prefix_len > 128) {
+			goto bad_prefix;
+		}
+	} else {
+		/* Get prefix length from elsewhere */
+		if (opt_n && a4)
+			prefix_len = opt_n;
+		else
+			prefix_len = inany_default_prefix_len(&addr);
+	}
 
-	if (inany_is_unspecified(&addr) || inany_is_multicast(&addr) ||
-	    inany_is_loopback(&addr) || IN6_IS_ADDR_V4COMPAT(&addr.a6))
-		die("Invalid address: %s", arg);
+	if (!parse_eoi(p)		||
+	    !inany_is_unicast(&addr)	||
+	    inany_is_loopback(&addr))
+		goto bad;
 
-	if (inany_v4(&addr)) {
-		c->ip4.addr = *inany_v4(&addr);
+	if (a4) {
+		c->ip4.addr = *a4;
 		c->ip4.prefix_len = prefix_len - 96;
 		c->ip4.addr_fixed = true;
-		if (c->mode == MODE_PASTA)
-			c->ip4.no_copy_addrs = true;
+		c->ip4.no_copy_addrs = true;
 	} else {
 		c->ip6.addr = addr.a6;
 		c->ip6.addr_fixed = true;
-		if (c->mode == MODE_PASTA)
-			c->ip6.no_copy_addrs = true;
+		c->ip6.no_copy_addrs = true;
 	}
 
 	return is_prefix;
+
+bad_prefix:
+	die("Invalid prefix length: %s", arg);
+bad:
+	die("Invalid guest address: %s", arg);
 }
 
 /**
diff --git a/inany.c b/inany.c
index 154f08b5..120c9387 100644
--- a/inany.c
+++ b/inany.c
@@ -70,53 +70,3 @@ const char *inany_ntop(const union inany_addr *src, char *dst, socklen_t size)
 
 	return inet_ntop(AF_INET6, &src->a6, dst, size);
 }
-
-/**
- * inany_prefix_pton() - Parse an IPv[46] address with prefix length
- * @src:	IPv[46] address and prefix length string in CIDR format
- * @dst:	Output buffer, filled with parsed address
- * @prefix_len:	Prefix length, to be filled in IPv6 format
- *
- * Return: 1 on success, 0 if no parseable address or prefix is found
- */
-int inany_prefix_pton(const char *src, union inany_addr *dst,
-		      uint8_t *prefix_len)
-{
-	char astr[INANY_ADDRSTRLEN] = { 0 };
-	size_t alen = strcspn(src, "/");
-	const char *pstr = &src[alen + 1];
-	const char *p = astr;
-	unsigned long plen;
-	char *end;
-
-	if (alen >= INANY_ADDRSTRLEN)
-		return 0;
-
-	if (src[alen] != '/')
-		return 0;
-
-	strncpy(astr, src, alen);
-
-	/* Read prefix length */
-	errno = 0;
-	plen = strtoul(pstr, &end, 10);
-	if (errno || *end || plen > 128)
-		return 0;
-
-	/* Read address */
-	if (inet_pton(AF_INET6, astr, dst)) {
-		if (inany_v4(dst) && plen < 96)
-			return 0;
-		*prefix_len = plen;
-		return 1;
-	}
-
-	if (parse_inany(&p, dst) && parse_eoi(p)) {
-		if (plen > 32)
-			return 0;
-		*prefix_len = plen + 96;
-		return 1;
-	}
-
-	return 0;
-}
diff --git a/inany.h b/inany.h
index 93d98368..5b176ccf 100644
--- a/inany.h
+++ b/inany.h
@@ -303,7 +303,5 @@ static inline int inany_from_sockaddr(union inany_addr *dst, in_port_t *port,
 
 bool inany_matches(const union inany_addr *a, const union inany_addr *b);
 const char *inany_ntop(const union inany_addr *src, char *dst, socklen_t size);
-int inany_prefix_pton(const char *src, union inany_addr *dst,
-		      uint8_t *prefix_len);
 
 #endif /* INANY_H */
diff --git a/parse.c b/parse.c
index 0349c5dc..3e0dbd45 100644
--- a/parse.c
+++ b/parse.c
@@ -184,18 +184,29 @@ static bool parse_ipv6(const char **cursor, struct in6_addr *abuf)
 }
 
 /**
- * parse_inany() - Parse an IPv4 or IPv6 address from a string
+ * parse_inany_() - Parse an IPv4 or IPv6 address from a string
  * @addr:	On success, updated with parsed address
+ * @parseaf:	On success, updated with the format of the parsed address
+ *
+ * @parseaf is updated to reflect the string format, not the final address
+ * family.  So "::ffff:192.0.1.1", will set @parseaf to AF_INET6, despite being
+ * a IPv4-mapped address.
  */
-bool parse_inany(const char **cursor, union inany_addr *addr)
+bool parse_inany_(const char **cursor, union inany_addr *addr,
+		  sa_family_t *parseaf)
 {
 	struct in_addr a4;
 
-	if (parse_ipv6(cursor, &addr->a6))
+	if (parse_ipv6(cursor, &addr->a6)) {
+		if (parseaf)
+			*parseaf = AF_INET6;
 		return true;
+	}
 
 	if (parse_ipv4(cursor, &a4)) {
 		*addr = inany_from_v4(a4);
+		if (parseaf)
+			*parseaf = AF_INET;
 		return true;
 	}
 
diff --git a/parse.h b/parse.h
index 2820a065..08b038cf 100644
--- a/parse.h
+++ b/parse.h
@@ -27,6 +27,9 @@ bool parse_eoi(const char *cursor);
 bool parse_unsigned(const char **cursor, int base, unsigned long *valp);
 bool parse_port_range(const char **cursor, struct port_range *range);
 bool parse_ipv4(const char **cursor, struct in_addr *abuf);
-bool parse_inany(const char **cursor, union inany_addr *addr);
+bool parse_inany_(const char **cursor, union inany_addr *addr,
+		 sa_family_t *parseaf);
+
+#define parse_inany(cursor, addr)	parse_inany_((cursor), (addr), NULL)
 
 #endif /* _PARSE_H */
-- 
2.54.0