net/if: Drop ifmediareq and just use the regular ifreq for SIOCGIFMEDIA.

This was introduced into the main API in 2010 (d72ede75fb),
but was actually only fully used for the past month (c2a9a890f3)
when SIOCGIFMEDIA was supported for all *BSD drivers and not just WiFi.
Most userland consumers of this structure did not use it correctly,
as was the case in #17770, and only worked because in the fallback case
the network stack just treated it as if it were an ifreq.

Nothing actually used the ifm_count/ifm_ulist (though tentative APIs
were exposed for it) as noted by previous commits; and the fact that
Haiku's IFM_* declarations are so spartan makes most of the returned
values unintelligible to userland without using FreeBSD compat headers.

If, in the future, we decide to implement ifmedia listing and selection
properly, that should likely be done with separate ioctls instead of
having multi-function ones like this.

This is technically an ABI break, but in practice it should not matter:
ifmediareq::ifm_current aligns with ifreq::ifr_media, so the things
that used this structure like our in-tree code did will continue to work.
Until this past May, the only other field that was usually set was
ifm_active, but in the absence of setting ifm_status all non-Haiku
consumers should ignore it completely.

The only consumer of this ioctl that I know of out of the tree,
wpa_supplicant, still works after these changes.

headers/os/net/NetworkDevice.h

@@ -99,9 +99,6 @@ public:
 			uint32				Flags() const;
 			bool				HasLink() const;
 
-			int32				CountMedia() const;
-			int32				GetMediaAt(int32 index) const;
-
 			int32				Media() const;
 			status_t			SetMedia(int32 media);
 

headers/posix/net/if.h

@@ -64,17 +64,6 @@ struct ifaliasreq {
 	uint32_t		ifra_flags;
 };
 
-/* used with SIOCGIFMEDIA */
-struct ifmediareq {
-	char			ifm_name[IF_NAMESIZE];
-	int				ifm_current;
-	int				ifm_mask;
-	int				ifm_status;
-	int				ifm_active;
-	int				ifm_count;
-	int*			ifm_ulist;
-};
-
 
 /* interface flags */
 #define IFF_UP				0x0001

src/add-ons/kernel/network/stack/datalink.cpp

@@ -918,19 +918,16 @@ interface_protocol_control(net_datalink_protocol* _protocol, int32 option,
 		case SIOCGIFMEDIA:
 		{
 			// get media
-			if (length > 0 && length < sizeof(ifmediareq))
+			const size_t copylen = offsetof(ifreq, ifr_media) + sizeof(ifreq::ifr_media);
+			if (length > 0 && length < copylen)
 				return B_BAD_VALUE;
 
-			struct ifmediareq request;
+			struct ifreq request;
-			if (user_memcpy(&request, argument, sizeof(request)) != B_OK)
+			if (user_memcpy(&request, argument, copylen) != B_OK)
 				return B_BAD_ADDRESS;
 
-			// TODO: Support retrieving the media list?
+			request.ifr_media = interface->device->media;
-			memset(&request, 0, sizeof(struct ifmediareq));
+			return user_memcpy(argument, &request, copylen);
-			request.ifm_active = request.ifm_current
-				= interface->device->media;
-
-			return user_memcpy(argument, &request, sizeof(request));
 		}
 
 		case SIOCGIFMETRIC:

src/add-ons/kernel/network/stack/link.cpp

@@ -455,30 +455,22 @@ link_control(net_protocol* _protocol, int level, int option, void* value,
 		case SIOCGIFMEDIA:
 		{
 			// get media
-			if (*_length > 0 && *_length < sizeof(ifmediareq))
+			const size_t copylen = offsetof(ifreq, ifr_media) + sizeof(ifreq::ifr_media);
+			if (*_length > 0 && *_length < copylen)
 				return B_BAD_VALUE;
 
 			net_device_interface* interface;
-			struct ifmediareq request;
+			struct ifreq request;
-			if (!user_request_get_device_interface(value, (ifreq&)request,
+			if (!user_request_get_device_interface(value, request, interface))
-					interface))
 				return B_BAD_ADDRESS;
-
 			if (interface == NULL)
 				return B_DEVICE_NOT_FOUND;
 
-			if (user_memcpy(&request, value, sizeof(ifmediareq)) != B_OK) {
+			request.ifr_media = interface->device->media;
-				put_device_interface(interface);
-				return B_BAD_ADDRESS;
-			}
-
-			// We do not support SIOCSIFMEDIA here, so ignore the media list.
-			memset(&request, 0, sizeof(struct ifmediareq));
-			request.ifm_active = request.ifm_current = interface->device->media;
 
 			put_device_interface(interface);
 
-			return user_memcpy(value, &request, sizeof(struct ifmediareq));
+			return user_memcpy(value, &request, copylen);
 		}
 
 		case SIOCSPACKETCAP:

src/kits/network/libnetapi/NetworkDevice.cpp

@@ -617,39 +617,14 @@ BNetworkDevice::HasLink() const
 }
 
 
-int32
-BNetworkDevice::CountMedia() const
-{
-	ifmediareq request;
-	request.ifm_count = 0;
-	request.ifm_ulist = NULL;
-
-	if (do_request(request, Name(), SIOCGIFMEDIA) != B_OK)
-		return -1;
-
-	return request.ifm_count;
-}
-
-
 int32
 BNetworkDevice::Media() const
 {
-	ifmediareq request;
+	ifreq request;
-	request.ifm_count = 0;
-	request.ifm_ulist = NULL;
-
 	if (do_request(request, Name(), SIOCGIFMEDIA) != B_OK)
 		return -1;
 
-	return request.ifm_current;
+	return request.ifr_media;
-}
-
-
-int32
-BNetworkDevice::GetMediaAt(int32 index) const
-{
-	// TODO: this could do some caching
-	return 0;
 }
 
 

src/kits/network/libnetapi/NetworkInterface.cpp

@@ -257,14 +257,11 @@ BNetworkInterface::MTU() const
 int32
 BNetworkInterface::Media() const
 {
-	ifmediareq request;
+	ifreq request;
-	request.ifm_count = 0;
-	request.ifm_ulist = NULL;
-
 	if (do_request(AF_INET, request, Name(), SIOCGIFMEDIA) != B_OK)
 		return -1;
 
-	return request.ifm_current;
+	return request.ifr_media;
 }
 
 

src/libs/compat/freebsd_network/compat/net/if.h

@@ -117,6 +117,16 @@ struct if_data {
 	struct	timeval ifi_lastchange;	/* time of last administrative change */
 };
 
+struct ifmediareq {
+	char	ifm_name[IFNAMSIZ];	/* if name, e.g. "en0" */
+	int	ifm_current;		/* current media options */
+	int	ifm_mask;		/* don't care mask */
+	int	ifm_status;		/* media status */
+	int	ifm_active;		/* active options */
+	int	ifm_count;		/* # entries in ifm_ulist array */
+	int	*ifm_ulist;		/* media words */
+};
+
 struct  ifdrv {
 	char			ifd_name[IFNAMSIZ];     /* if name, e.g. "en0" */
 	unsigned long	ifd_cmd;

src/libs/compat/freebsd_network/device_hooks.c

@@ -328,7 +328,6 @@ compat_control(void *cookie, uint32 op, void *arg, size_t length)
 
 		case SIOCSIFFLAGS:
 		case SIOCSIFMEDIA:
-		case SIOCGIFMEDIA:
 		case SIOCSIFMTU:
 		{
 			IFF_LOCKGIANT(ifp);