fwd_rule: Move ephemeral port probing to fwd_rule.c

We want to move parsing of forward rule options to fwd_rule.c so it can
eventually be shared with a configuration client.  As a preliminary step,
move the ephemeral port probing there, which that will need to use.

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

4 files changed, 84 insertions, 79 deletions

diff --git a/fwd.c b/fwd.c
index 979c149..a6d75b7 100644
--- a/fwd.c
+++ b/fwd.c
@@ -34,12 +34,6 @@
 #include "arp.h"
 #include "ndp.h"
 
-/* Ephemeral port range: values from RFC 6335 */
-static in_port_t fwd_ephemeral_min = (1 << 15) + (1 << 14);
-static in_port_t fwd_ephemeral_max = NUM_PORTS - 1;
-
-#define PORT_RANGE_SYSCTL	"/proc/sys/net/ipv4/ip_local_port_range"
-
 #define NEIGH_TABLE_SLOTS    1024
 #define NEIGH_TABLE_SIZE     (NEIGH_TABLE_SLOTS / 2)
 static_assert((NEIGH_TABLE_SLOTS & (NEIGH_TABLE_SLOTS - 1)) == 0,
@@ -249,73 +243,6 @@ void fwd_neigh_table_init(const struct ctx *c)
 		fwd_neigh_table_update(c, &mga, c->our_tap_mac, true);
 }
 
-/** fwd_probe_ephemeral() - Determine what ports this host considers ephemeral
- *
- * Work out what ports the host thinks are emphemeral and record it for later
- * use by fwd_port_is_ephemeral().  If we're unable to probe, assume the range
- * recommended by RFC 6335.
- */
-void fwd_probe_ephemeral(void)
-{
-	char *line, *tab, *end;
-	struct lineread lr;
-	long min, max;
-	ssize_t len;
-	int fd;
-
-	fd = open(PORT_RANGE_SYSCTL, O_RDONLY | O_CLOEXEC);
-	if (fd < 0) {
-		warn_perror("Unable to open %s", PORT_RANGE_SYSCTL);
-		return;
-	}
-
-	lineread_init(&lr, fd);
-	len = lineread_get(&lr, &line);
-	close(fd);
-
-	if (len < 0)
-		goto parse_err;
-
-	tab = strchr(line, '\t');
-	if (!tab)
-		goto parse_err;
-	*tab = '\0';
-
-	errno = 0;
-	min = strtol(line, &end, 10);
-	if (*end || errno)
-		goto parse_err;
-
-	errno = 0;
-	max = strtol(tab + 1, &end, 10);
-	if (*end || errno)
-		goto parse_err;
-
-	if (min < 0 || min >= (long)NUM_PORTS ||
-	    max < 0 || max >= (long)NUM_PORTS)
-		goto parse_err;
-
-	fwd_ephemeral_min = min;
-	fwd_ephemeral_max = max;
-
-	return;
-
-parse_err:
-	warn("Unable to parse %s", PORT_RANGE_SYSCTL);
-}
-
-/**
- * fwd_port_map_ephemeral() - Mark ephemeral ports in a bitmap
- * @map:	Bitmap to update
- */
-void fwd_port_map_ephemeral(uint8_t *map)
-{
-	unsigned port;
-
-	for (port = fwd_ephemeral_min; port <= fwd_ephemeral_max; port++)
-		bitmap_set(map, port);
-}
-
 /* Forwarding table storage, generally accessed via pointers in struct ctx */
 static struct fwd_table fwd_in;
 static struct fwd_table fwd_out;
diff --git a/fwd.h b/fwd.h
index 3e365d3..e664d1d 100644
--- a/fwd.h
+++ b/fwd.h
@@ -20,12 +20,6 @@
 
 struct flowside;
 
-/* Number of ports for both TCP and UDP */
-#define	NUM_PORTS	(1U << 16)
-
-void fwd_probe_ephemeral(void);
-void fwd_port_map_ephemeral(uint8_t *map);
-
 #define FWD_RULE_BITS	8
 #define MAX_FWD_RULES	MAX_FROM_BITS(FWD_RULE_BITS)
 #define FWD_NO_HINT	(-1)
diff --git a/fwd_rule.c b/fwd_rule.c
index 47d8df1..9d48982 100644
--- a/fwd_rule.c
+++ b/fwd_rule.c
@@ -15,9 +15,87 @@
  * Author: David Gibson <david@gibson.dropbear.id.au>
  */
 
+#include <errno.h>
+#include <fcntl.h>
 #include <stdio.h>
+#include <unistd.h>
 
 #include "fwd_rule.h"
+#include "lineread.h"
+#include "log.h"
+
+/* Ephemeral port range: values from RFC 6335 */
+static in_port_t fwd_ephemeral_min = (1 << 15) + (1 << 14);
+static in_port_t fwd_ephemeral_max = NUM_PORTS - 1;
+
+#define PORT_RANGE_SYSCTL	"/proc/sys/net/ipv4/ip_local_port_range"
+
+/** fwd_probe_ephemeral() - Determine what ports this host considers ephemeral
+ *
+ * Work out what ports the host thinks are emphemeral and record it for later
+ * use by fwd_port_is_ephemeral().  If we're unable to probe, assume the range
+ * recommended by RFC 6335.
+ */
+void fwd_probe_ephemeral(void)
+{
+	char *line, *tab, *end;
+	struct lineread lr;
+	long min, max;
+	ssize_t len;
+	int fd;
+
+	fd = open(PORT_RANGE_SYSCTL, O_RDONLY | O_CLOEXEC);
+	if (fd < 0) {
+		warn_perror("Unable to open %s", PORT_RANGE_SYSCTL);
+		return;
+	}
+
+	lineread_init(&lr, fd);
+	len = lineread_get(&lr, &line);
+	close(fd);
+
+	if (len < 0)
+		goto parse_err;
+
+	tab = strchr(line, '\t');
+	if (!tab)
+		goto parse_err;
+	*tab = '\0';
+
+	errno = 0;
+	min = strtol(line, &end, 10);
+	if (*end || errno)
+		goto parse_err;
+
+	errno = 0;
+	max = strtol(tab + 1, &end, 10);
+	if (*end || errno)
+		goto parse_err;
+
+	if (min < 0 || min >= (long)NUM_PORTS ||
+	    max < 0 || max >= (long)NUM_PORTS)
+		goto parse_err;
+
+	fwd_ephemeral_min = min;
+	fwd_ephemeral_max = max;
+
+	return;
+
+parse_err:
+	warn("Unable to parse %s", PORT_RANGE_SYSCTL);
+}
+
+/**
+ * fwd_port_map_ephemeral() - Mark ephemeral ports in a bitmap
+ * @map:	Bitmap to update
+ */
+void fwd_port_map_ephemeral(uint8_t *map)
+{
+	unsigned port;
+
+	for (port = fwd_ephemeral_min; port <= fwd_ephemeral_max; port++)
+		bitmap_set(map, port);
+}
 
 /**
  * fwd_rule_addr() - Return match address for a rule
diff --git a/fwd_rule.h b/fwd_rule.h
index edba678..5c7b67a 100644
--- a/fwd_rule.h
+++ b/fwd_rule.h
@@ -17,6 +17,9 @@
 #include "inany.h"
 #include "bitmap.h"
 
+/* Number of ports for both TCP and UDP */
+#define	NUM_PORTS	(1U << 16)
+
 /* Forwarding capability bits */
 #define FWD_CAP_IPV4		BIT(0)
 #define FWD_CAP_IPV6		BIT(1)
@@ -51,6 +54,9 @@ struct fwd_rule {
 	uint8_t flags;
 };
 
+void fwd_probe_ephemeral(void);
+void fwd_port_map_ephemeral(uint8_t *map);
+
 #define FWD_RULE_STRLEN					    \
 	(IPPROTO_STRLEN - 1				    \
 	 + INANY_ADDRSTRLEN - 1				    \