parse: Add helpers for parsing IP addresses

parse_ipv[46]() are wrappers around inet_pton() that are more
convenient for use when the IP is part of a longer string, rather than
the entire string.  parse_inany() replaces inany_pton() which again
will become more convenient for strings including IPs that aren't just
an IP.

For now we only have some simple and sometimes awkward use cases,
we'll replace these with more natural uses in future.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

7 files changed, 109 insertions, 39 deletions

diff --git a/Makefile b/Makefile
index 85d279c..e2b22dd 100644
--- a/Makefile
+++ b/Makefile
@@ -227,4 +227,5 @@ 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
+pesto.cppcheck: CPPCHECK_FLAGS += --suppress=staticFunction:parse.c
 pesto.cppcheck: $(PESTO_SRCS) $(PESTO_HEADERS) seccomp_pesto.h
diff --git a/conf.c b/conf.c
index bd35711..2d1895d 100644
--- a/conf.c
+++ b/conf.c
@@ -357,7 +357,7 @@ static uint8_t conf_ip4_prefix(const char *arg)
 	struct in_addr mask;
 	unsigned long len;
 
-	if (inet_pton(AF_INET, arg, &mask)) {
+	if (parse_ipv4(&p, &mask) && parse_eoi(p)) {
 		in_addr_t hmask = ntohl(mask.s_addr);
 		len = __builtin_popcount(hmask);
 		if ((hmask << len) == 0)
@@ -1577,7 +1577,9 @@ void conf(struct ctx *c, int argc, char **argv)
 			if (addr_has_prefix_len && prefix_len_from_opt)
 				die("Redundant prefix length specification");
 
-			if (!addr_has_prefix_len && !inany_pton(optarg, &addr))
+			p = optarg;
+			if (!addr_has_prefix_len &&
+			    !(parse_inany(&p, &addr) && parse_eoi(p)))
 				die("Invalid address: %s", optarg);
 
 			if (prefix_len_from_opt && inany_v4(&addr))
diff --git a/fwd_rule.c b/fwd_rule.c
index 0b85b17..6d7ec2c 100644
--- a/fwd_rule.c
+++ b/fwd_rule.c
@@ -595,6 +595,8 @@ void fwd_rule_parse(char optname, bool del, const char *optarg,
 	strncpy(buf, optarg, sizeof(buf) - 1);
 
 	if ((spec = strchr(buf, '/'))) {
+		const char *p = buf;
+
 		*spec = 0;
 		spec++;
 
@@ -616,22 +618,11 @@ void fwd_rule_parse(char optname, bool del, const char *optarg,
 			}
 		}
 
-		if (ifname == buf + 1) {	/* Interface without address */
+		if (ifname == buf + 1 || /* Interface without address */
+		    !strcmp(buf, "*")) /* Explicit wildcard address */
 			addr = NULL;
-		} else {
-			char *p = buf;
-
-			/* Allow square brackets for IPv4 too for convenience */
-			if (*p == '[' && p[strlen(p) - 1] == ']') {
-				p[strlen(p) - 1] = '\0';
-				p++;
-			}
-
-			if (strcmp(p, "*") == 0)
-				addr = NULL;
-			else if (!inany_pton(p, &addr_buf))
-				die("Bad forwarding address '%s'", p);
-		}
+		else if (!parse_inany(&p, &addr_buf) && parse_eoi(p))
+			die("Bad forwarding address '%s'", buf);
 	} else {
 		spec = buf;
 
diff --git a/inany.c b/inany.c
index 23faf3f..154f08b 100644
--- a/inany.c
+++ b/inany.c
@@ -27,6 +27,7 @@
 #include "ip.h"
 #include "inany.h"
 #include "fwd.h"
+#include "parse.h"
 
 const union inany_addr inany_loopback4 = INANY_INIT4(IN4ADDR_LOOPBACK_INIT);
 const union inany_addr inany_any4 = INANY_INIT4(IN4ADDR_ANY_INIT);
@@ -70,26 +71,6 @@ const char *inany_ntop(const union inany_addr *src, char *dst, socklen_t size)
 	return inet_ntop(AF_INET6, &src->a6, dst, size);
 }
 
-/** inany_pton - Parse an IPv[46] address from text format
- * @src:	IPv[46] address
- * @dst:	output buffer, filled with parsed address
- *
- * Return: on success, 1, if no parseable address is found, 0
- */
-int inany_pton(const char *src, union inany_addr *dst)
-{
-	if (inet_pton(AF_INET, src, &dst->v4mapped.a4)) {
-		memset(&dst->v4mapped.zero, 0, sizeof(dst->v4mapped.zero));
-		memset(&dst->v4mapped.one, 0xff, sizeof(dst->v4mapped.one));
-		return 1;
-	}
-
-	if (inet_pton(AF_INET6, src, &dst->a6))
-		return 1;
-
-	return 0;
-}
-
 /**
  * inany_prefix_pton() - Parse an IPv[46] address with prefix length
  * @src:	IPv[46] address and prefix length string in CIDR format
@@ -104,6 +85,7 @@ int inany_prefix_pton(const char *src, union inany_addr *dst,
 	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;
 
@@ -129,7 +111,7 @@ int inany_prefix_pton(const char *src, union inany_addr *dst,
 		return 1;
 	}
 
-	if (inany_pton(astr, dst)) {
+	if (parse_inany(&p, dst) && parse_eoi(p)) {
 		if (plen > 32)
 			return 0;
 		*prefix_len = plen + 96;
diff --git a/inany.h b/inany.h
index 6bf3eca..93d9836 100644
--- a/inany.h
+++ b/inany.h
@@ -303,7 +303,6 @@ 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_pton(const char *src, union inany_addr *dst);
 int inany_prefix_pton(const char *src, union inany_addr *dst,
 		      uint8_t *prefix_len);
 
diff --git a/parse.c b/parse.c
index ad21040..c8d3a9b 100644
--- a/parse.c
+++ b/parse.c
@@ -16,9 +16,12 @@
 #include <stddef.h>
 #include <stdlib.h>
 #include <string.h>
+#include <limits.h>
+#include <arpa/inet.h>
 
 #include "common.h"
 #include "parse.h"
+#include "inany.h"
 
 /**
  * DOC: Theory of Operation
@@ -111,3 +114,91 @@ bool parse_port_range(const char **cursor, struct port_range *range)
 	*cursor = p;
 	return true;
 }
+
+/**
+ * parse_ipv4() - Parse an IPv4 address from a string
+ * @abuf:	On success, updated with parsed address
+ */
+bool parse_ipv4(const char **cursor, struct in_addr *abuf)
+{
+	/* Brackets are not typical on IPv4, but allow for consistency */
+	const char *p = *cursor;
+	bool bracket = parse_literal(&p, "[");
+	char buf[INET_ADDRSTRLEN];
+	struct in_addr addr;
+	size_t len;
+
+	if (bracket)
+		len = strcspn(p, "]");
+	else
+		len = strspn(p, "0123456789.");
+
+	if (len >= sizeof(buf))
+		return false;
+	memcpy(buf, p, len);
+	buf[len] = '\0';
+	p += len;
+
+	if (!inet_pton(AF_INET, buf, &addr))
+		return false;
+
+	if (bracket && !parse_literal(&p, "]"))
+		return false;
+
+	*cursor = p;
+	*abuf = addr;
+	return true;
+}
+
+/**
+ * parse_ipv6() - Parse an IPv6 address from a string
+ * @abuf:	On success, updated with parsed address
+ */
+static bool parse_ipv6(const char **cursor, struct in6_addr *abuf)
+{
+	const char *p = *cursor;
+	bool bracket = parse_literal(&p, "[");
+	char buf[INET6_ADDRSTRLEN];
+	struct in6_addr addr;
+	size_t len;
+
+	if (bracket)
+		len = strcspn(p, "]");
+	else
+		len = strspn(p, "0123456789aAbBcCdDeEfF:.");
+
+	if (len >= sizeof(buf))
+		return false;
+	memcpy(buf, p, len);
+	buf[len] = '\0';
+	p += len;
+
+	if (!inet_pton(AF_INET6, buf, &addr))
+		return false;
+
+	if (bracket && !parse_literal(&p, "]"))
+		return false;
+
+	*cursor = p;
+	*abuf = addr;
+	return true;
+}
+
+/**
+ * parse_inany() - Parse an IPv4 or IPv6 address from a string
+ * @addr:	On success, updated with parsed address
+ */
+bool parse_inany(const char **cursor, union inany_addr *addr)
+{
+	struct in_addr a4;
+
+	if (parse_ipv6(cursor, &addr->a6))
+		return true;
+
+	if (parse_ipv4(cursor, &a4)) {
+		*addr = inany_from_v4(a4);
+		return true;
+	}
+
+	return false;
+}
diff --git a/parse.h b/parse.h
index 155b399..2820a06 100644
--- a/parse.h
+++ b/parse.h
@@ -9,6 +9,8 @@
 #include <stdbool.h>
 #include <netinet/in.h>
 
+union inany_addr;
+
 /**
  * port_range() - Represents a non-empty range of ports
  * @first:	First port number in the range
@@ -24,5 +26,7 @@ bool parse_literal(const char **cursor, const char *lit);
 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);
 
 #endif /* _PARSE_H */