linux: add sysctl to pass untranslated interface names

Reviewed by:	kib
MFC after:	2 weeks
Differential Revision: https://reviews.freebsd.org/D33792

(cherry picked from commit 1f70a85b4cbc3ad19cec4a390e8754e54815be85)

5 files changed, 28 insertions, 15 deletions

diff --git a/sys/compat/linprocfs/linprocfs.c b/sys/compat/linprocfs/linprocfs.c
index a363644da744..27acd7d651a7 100644
--- a/sys/compat/linprocfs/linprocfs.c
+++ b/sys/compat/linprocfs/linprocfs.c
@@ -1414,11 +1414,6 @@ linprocfs_doprocmem(PFS_FILL_ARGS)
 	return (error);
 }
 
-/*
- * Criteria for interface name translation
- */
-#define IFP_IS_ETH(ifp) (ifp->if_type == IFT_ETHER)
-
 static int
 linux_ifname(struct ifnet *ifp, char *buffer, size_t buflen)
 {
@@ -1428,7 +1423,7 @@ linux_ifname(struct ifnet *ifp, char *buffer, size_t buflen)
 	IFNET_RLOCK_ASSERT();
 
 	/* Short-circuit non ethernet interfaces */
-	if (!IFP_IS_ETH(ifp))
+	if (linux_use_real_ifname(ifp))
 		return (strlcpy(buffer, ifp->if_xname, buflen));
 
 	/* Determine the (relative) unit number for ethernet interfaces */
@@ -1436,7 +1431,7 @@ linux_ifname(struct ifnet *ifp, char *buffer, size_t buflen)
 	CK_STAILQ_FOREACH(ifscan, &V_ifnet, if_link) {
 		if (ifscan == ifp)
 			return (snprintf(buffer, buflen, "eth%d", ethno));
-		if (IFP_IS_ETH(ifscan))
+		if (!linux_use_real_ifname(ifscan))
 			ethno++;
 	}
 
diff --git a/sys/compat/linux/linux.h b/sys/compat/linux/linux.h
index 18eafa88a432..ba7a96e1aa79 100644
--- a/sys/compat/linux/linux.h
+++ b/sys/compat/linux/linux.h
@@ -34,12 +34,6 @@
 #define	LINUX_IFHWADDRLEN	6
 #define	LINUX_IFNAMSIZ		16
 
-/*
- * Criteria for interface name translation
- */
-#define	IFP_IS_ETH(ifp)		(ifp->if_type == IFT_ETHER)
-#define	IFP_IS_LOOP(ifp)	(ifp->if_type == IFT_LOOP)
-
 struct l_sockaddr {
 	unsigned short	sa_family;
 	char		sa_data[14];
diff --git a/sys/compat/linux/linux_ioctl.c b/sys/compat/linux/linux_ioctl.c
index 101a52698a0a..cd89c16cad64 100644
--- a/sys/compat/linux/linux_ioctl.c
+++ b/sys/compat/linux/linux_ioctl.c
@@ -2121,7 +2121,7 @@ linux_ioctl_ifname(struct thread *td, struct l_ifreq *uifr)
 	error = ENODEV;
 	CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
 		if (ifr.ifr_ifindex == index) {
-			if (IFP_IS_ETH(ifp))
+			if (!linux_use_real_ifname(ifp))
 				snprintf(ifr.ifr_name, LINUX_IFNAMSIZ,
 				    "eth%d", ethno);
 			else
@@ -2130,7 +2130,7 @@ linux_ioctl_ifname(struct thread *td, struct l_ifreq *uifr)
 			error = 0;
 			break;
 		}
-		if (IFP_IS_ETH(ifp))
+		if (!linux_use_real_ifname(ifp))
 			ethno++;
 		index++;
 	}
diff --git a/sys/compat/linux/linux_util.c b/sys/compat/linux/linux_util.c
index 8e5462636705..86266fd3178f 100644
--- a/sys/compat/linux/linux_util.c
+++ b/sys/compat/linux/linux_util.c
@@ -52,6 +52,10 @@ __FBSDID("$FreeBSD$");
 #include <sys/systm.h>
 #include <sys/vnode.h>
 
+#include <net/if.h>
+#include <net/if_var.h>
+#include <net/if_types.h>
+
 #include <machine/stdarg.h>
 
 #include <compat/linux/linux_dtrace.h>
@@ -86,6 +90,11 @@ SYSCTL_STRING(_compat_linux, OID_AUTO, emul_path, CTLFLAG_RWTUN,
     linux_emul_path, sizeof(linux_emul_path),
     "Linux runtime environment path");
 
+static bool use_real_ifnames = false;
+SYSCTL_BOOL(_compat_linux, OID_AUTO, use_real_ifnames, CTLFLAG_RWTUN,
+    &use_real_ifnames, 0,
+    "Use FreeBSD interface names instead of generating ethN aliases");
+
 /*
  * Search an alternate path before passing pathname arguments on to
  * system calls. Useful for keeping a separate 'emulation tree'.
@@ -319,3 +328,9 @@ linux_device_unregister_handler(struct linux_device_handler *d)
 
 	return (EINVAL);
 }
+
+bool
+linux_use_real_ifname(const struct ifnet *ifp)
+{
+	return (use_real_ifnames || !IFP_IS_ETH(ifp));
+}
diff --git a/sys/compat/linux/linux_util.h b/sys/compat/linux/linux_util.h
index 436d4313abc8..681c03c625e4 100644
--- a/sys/compat/linux/linux_util.h
+++ b/sys/compat/linux/linux_util.h
@@ -127,6 +127,15 @@ int	linux_vn_get_major_minor(const struct vnode *vn, int *major, int *minor);
 char	*linux_get_char_devices(void);
 void	linux_free_get_char_devices(char *string);
 
+/*
+ * Criteria for interface name translation
+ */
+#define	IFP_IS_ETH(ifp)		((ifp)->if_type == IFT_ETHER)
+#define	IFP_IS_LOOP(ifp)	((ifp)->if_type == IFT_LOOP)
+
+struct ifnet;
+bool	linux_use_real_ifname(const struct ifnet *ifp);
+
 #if defined(KTR)
 
 #define	KTR_LINUX				KTR_SUBSYS