Linux: set broadcast flag by default for ipvlan interfaces.

Author: ido

src/common.h

@@ -63,6 +63,10 @@
 #define ROUNDUP4(a)		(1 + (((a) - 1) |  3))
 #define ROUNDUP8(a)		(1 + (((a) - 1) |  7))
 
+#ifndef FIELD_SIZEOF
+#define FIELD_SIZEOF(t, f) sizeof(((t *)0)->f)
+#endif
+
 /* Some systems don't define timespec macros */
 #ifndef timespecclear
 #define timespecclear(tsp)      (tsp)->tv_sec = (time_t)((tsp)->tv_nsec = 0L)

src/if-linux.c

@@ -310,44 +310,29 @@ if_init(struct interface *ifp)
 	return if_writepathuint(ifp->ctx, path, 1) == -1 ? -1 : 0;
 }
 
-/* Returns number of bytes written to driver, 0 on error.
- * @driverlen note that sizeof(ethtool_drvinfo.driver) = 32 */
+/* Returns number of bytes written to driver, else 0 (error or indeterminate). */
 static size_t
-if_get_driver(const char *ifname, char *driver, const size_t driverlen)
+if_get_driver(struct interface *ifp, char *driver, const size_t driverlen)
 {
-	struct ifreq ifr = { .ifr_flags = 0 };
-	struct ethtool_drvinfo drvinfo;
-	int fd;
-	size_t n = 0;
+	struct ethtool_drvinfo drvinfo = { .cmd = ETHTOOL_GDRVINFO };
+	struct ifreq ifr = { .ifr_data = (void *)&drvinfo };
 
-	fd = socket(AF_INET, SOCK_STREAM, 0);
-	if (fd == -1) {
-		logerr("%s: socket ifname=%s", __func__, ifname);
-		goto eexit;
-	}
-	memset(&ifr, 0, sizeof(ifr));
-	strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
-	drvinfo.cmd = ETHTOOL_GDRVINFO;
-	ifr.ifr_data = (void *)&drvinfo;
-	if (ioctl(fd, SIOCETHTOOL, &ifr) == -1) {
-		logerr("%s: SIOCETHTOOL ifname=%s", __func__, ifname);
-		goto eexit;
+	strlcpy(ifr.ifr_name, ifp->name, sizeof(ifr.ifr_name));
+	if (ioctl(ifp->ctx->pf_inet_fd, SIOCETHTOOL, &ifr) != 0) {
+		logerr("%s: SIOCETHTOOL ifname=%s", __func__, ifp->name);
+		return 0; /* 0 means error or indeterminate driver name */
 	}
-	n = strlcpy(driver, drvinfo.driver, driverlen);
-eexit:
-	if (fd != -1)
-		close(fd);
-	return n;
+	return strlcpy(driver, drvinfo.driver, driverlen);
 }
 
 static bool
-if_cmp_driver(const char *ifname, const char *driver)
+if_cmp_driver(struct interface *ifp, const char *driver)
 {
-	char ifdriver[32]; /* see ethtool_drvinfo.driver declaration */
-	size_t n = if_get_driver(ifname, ifdriver, sizeof(ifdriver));
+	char ifdriver[FIELD_SIZEOF(struct ethtool_drvinfo, driver)];
+	size_t n = if_get_driver(ifp, ifdriver, sizeof(ifdriver));
 
 	if (n == 0) {
-		logerr("%s: if_get_driver ifname=%s", __func__, ifname);
+		logerr("%s: if_get_driver ifname=%s", __func__, ifp->name);
 		return false;
 	}
 	if (strncmp(ifdriver, driver, n) == 0)
@@ -358,7 +343,7 @@ if_cmp_driver(const char *ifname, const char *driver)
 static bool
 if_ipvlan(struct interface *ifp)
 {
-	if (if_cmp_driver(ifp->name, "ipvlan"))
+	if (if_cmp_driver(ifp, "ipvlan"))
 		return true;
 	return false;
 }