MFC r318160, 318176: Persistently store NIC's hardware MAC address, and add

a way to retrive it

NOTE: Due to restructuring, the merges didn't apply cleanly; the resulting
change is almost identical to what went into stable/11, but in some cases in
different locations.

The MAC address reported by `ifconfig ${nic} ether' does not always match
the address in the hardware, as reported by the driver during attach. In
particular, NICs which are components of a lagg(4) interface all report the
same MAC.

When attaching, the NIC driver passes the MAC address it read from the
hardware as an argument to ether_ifattach(). Keep a second copy of it, and
create ioctl(SIOCGHWADDR) to return it. Teach `ifconfig' to report it along
with the active MAC address.

PR:		194386

sbin/ifconfig/af_link.c

@@ -42,6 +42,7 @@ static const char rcsid[] =
 #include <stdlib.h>
 #include <string.h>
 #include <ifaddrs.h>
+#include <unistd.h>
 
 #include <net/if_dl.h>
 #include <net/if_types.h>
@@ -69,6 +70,41 @@ link_status(int s __unused, const struct ifaddrs *ifa)
 
 			printf("\tlladdr %s\n", link_ntoa(sdl) + n);
 		}
+		/* Best-effort (i.e. failures are silent) to get original
+		 * hardware address, as read by NIC driver at attach time. Only
+		 * applies to Ethernet NICs (IFT_ETHER). However, laggX
+		 * interfaces claim to be IFT_ETHER, and re-type their component
+		 * Ethernet NICs as IFT_IEEE8023ADLAG. So, check for both. If
+		 * the MAC is zeroed, then it's actually a lagg.
+		 */
+		if ((sdl->sdl_type == IFT_ETHER ||
+		    sdl->sdl_type == IFT_IEEE8023ADLAG) &&
+		    sdl->sdl_alen == ETHER_ADDR_LEN) {
+			struct ifreq ifr;
+			int sock_hw;
+			int rc;
+			static const u_char laggaddr[6] = {0};
+
+			strncpy(ifr.ifr_name, ifa->ifa_name,
+			    sizeof(ifr.ifr_name));
+			memcpy(&ifr.ifr_addr, ifa->ifa_addr,
+			    sizeof(ifa->ifa_addr->sa_len));
+			ifr.ifr_addr.sa_family = AF_LOCAL;
+			if ((sock_hw = socket(AF_LOCAL, SOCK_DGRAM, 0)) < 0) {
+				warn("socket(AF_LOCAL,SOCK_DGRAM)");
+				return;
+			}
+			rc = ioctl(sock_hw, SIOCGHWADDR, &ifr);
+			close(sock_hw);
+			if (rc != 0) {
+				return;
+			}
+			if (memcmp(ifr.ifr_addr.sa_data, laggaddr, sdl->sdl_alen) == 0) {
+				return;
+			}
+			printf("\thwaddr %s\n", ether_ntoa((const struct ether_addr *)
+			    &ifr.ifr_addr.sa_data));
+		}
 	}
 }
 

sys/net/if.c

@@ -732,6 +732,11 @@ if_attach_internal(struct ifnet *ifp, int vmove, struct if_clone *ifc)
 		/* Reliably crash if used uninitialized. */
 		ifp->if_broadcastaddr = NULL;
 
+		if (ifp->if_type == IFT_ETHER) {
+			ifp->if_hw_addr = malloc(ifp->if_addrlen, M_IFADDR,
+			    M_WAITOK | M_ZERO);
+		}
+
 #if defined(INET) || defined(INET6)
 		/* Use defaults for TSO, if nothing is set */
 		if (ifp->if_hw_tsomax == 0 &&
@@ -988,6 +993,8 @@ if_detach_internal(struct ifnet *ifp, int vmove, struct if_clone **ifcp)
 		 * Remove link ifaddr pointer and maybe decrement if_index.
 		 * Clean up all addresses.
 		 */
+		free(ifp->if_hw_addr, M_IFADDR);
+		ifp->if_hw_addr = NULL;
 		ifp->if_addr = NULL;
 
 		/* We can now free link ifaddr. */
@@ -2639,6 +2646,10 @@ ifhwioctl(u_long cmd, struct ifnet *ifp, caddr_t data, struct thread *td)
 		EVENTHANDLER_INVOKE(iflladdr_event, ifp);
 		break;
 
+	case SIOCGHWADDR:
+		error = if_gethwaddr(ifp, ifr);
+		break;
+
 	case SIOCAIFGROUP:
 	{
 		struct ifgroupreq *ifgr = (struct ifgroupreq *)ifr;
@@ -3577,6 +3588,29 @@ if_setlladdr(struct ifnet *ifp, const u_char *lladdr, int len)
 	return (0);
 }
 
+/*
+ * Get the link layer address that was read from the hardware at attach.
+ *
+ * This is only set by Ethernet NICs (IFT_ETHER), but laggX interfaces re-type
+ * their component interfaces as IFT_IEEE8023ADLAG.
+ */
+int
+if_gethwaddr(struct ifnet *ifp, struct ifreq *ifr)
+{
+
+	if (ifp->if_hw_addr == NULL)
+		return (ENODEV);
+
+	switch (ifp->if_type) {
+	case IFT_ETHER:
+	case IFT_IEEE8023ADLAG:
+		bcopy(ifp->if_hw_addr, ifr->ifr_addr.sa_data, ifp->if_addrlen);
+		return (0);
+	default:
+		return (ENODEV);
+	}
+}
+
 /*
  * The name argument must be a pointer to storage which will last as
  * long as the interface does.  For physical devices, the result of

sys/net/if_ethersubr.c

@@ -918,6 +918,9 @@ ether_ifattach(struct ifnet *ifp, const u_int8_t *lla)
 	sdl->sdl_alen = ifp->if_addrlen;
 	bcopy(lla, LLADDR(sdl), ifp->if_addrlen);
 
+	if (ifp->if_hw_addr != NULL)
+		bcopy(lla, ifp->if_hw_addr, ifp->if_addrlen);
+
 	bpfattach(ifp, DLT_EN10MB, ETHER_HDR_LEN);
 	if (ng_ether_attach_p != NULL)
 		(*ng_ether_attach_p)(ifp);

sys/net/if_var.h

@@ -200,6 +200,7 @@ struct ifnet {
 		(struct ifnet *, struct vnet *, char *);
 	struct	vnet *if_home_vnet;	/* where this ifnet originates from */
 	struct	ifaddr	*if_addr;	/* pointer to link-level address */
+	void	*if_hw_addr;		/* hardware link-level address */
 	void	*if_llsoftc;		/* link layer softc */
 	int	if_drv_flags;		/* driver-managed status flags */
 	struct  ifaltq if_snd;		/* output queue (includes altq) */
@@ -973,6 +974,7 @@ void	if_qflush(struct ifnet *);
 void	if_ref(struct ifnet *);
 void	if_rele(struct ifnet *);
 int	if_setlladdr(struct ifnet *, const u_char *, int);
+int	if_gethwaddr(struct ifnet *, struct ifreq *);
 void	if_up(struct ifnet *);
 int	ifioctl(struct socket *, u_long, caddr_t, struct thread *);
 int	ifpromisc(struct ifnet *, int);

sys/sys/sockio.h

@@ -97,6 +97,7 @@
 #define	SIOCGIFSTATUS	_IOWR('i', 59, struct ifstat)	/* get IF status */
 #define	SIOCSIFLLADDR	 _IOW('i', 60, struct ifreq)	/* set linklevel addr */
 #define	SIOCGI2C	_IOWR('i', 61, struct ifreq)	/* get I2C data  */
+#define	SIOCGHWADDR	_IOWR('i', 62, struct ifreq)	/* get hardware lladdr */
 
 #define	SIOCSIFPHYADDR	 _IOW('i', 70, struct ifaliasreq) /* set gif address */
 #define	SIOCGIFPSRCADDR	_IOWR('i', 71, struct ifreq)	/* get gif psrc addr */