[INFINIBAND]: IPoIB IPv4 multicast

Add ip_ib_mc_map() to convert IPv4 multicast addresses to IPoIB
hardware addresses.  Also add <linux/if_infiniband.h> so INFINIBAND_ALEN
has a home.

The mapping for multicast addresses is described in
  http://www.ietf.org/internet-drafts/draft-ietf-ipoib-ip-over-infiniband-08.txtSigned-off-by: Roland Dreier <roland@topspin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/if_infiniband.h

+/*
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available at
+ * <http://www.fsf.org/copyleft/gpl.html>, or the OpenIB.org BSD
+ * license, available in the LICENSE.TXT file accompanying this
+ * software.  These details are also available at
+ * <http://openib.org/license.html>.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * Copyright (c) 2004 Topspin Communications.  All rights reserved.
+ *
+ * $Id$
+ */
+
+#ifndef _LINUX_IF_INFINIBAND_H
+#define _LINUX_IF_INFINIBAND_H
+
+#define INFINIBAND_ALEN		20	/* Octets in IPoIB HW addr	*/
+
+#endif /* _LINUX_IF_INFINIBAND_H */

include/net/ip.h

@@ -229,6 +229,39 @@ static inline void ip_eth_mc_map(u32 addr, char *buf)
 	buf[3]=addr&0x7F;
 }
 
+/*
+ *	Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
+ *	Leave P_Key as 0 to be filled in by driver.
+ */
+
+static inline void ip_ib_mc_map(u32 addr, char *buf)
+{
+	buf[0]  = 0;		/* Reserved */
+	buf[1]  = 0xff;		/* Multicast QPN */
+	buf[2]  = 0xff;
+	buf[3]  = 0xff;
+	addr    = ntohl(addr);
+	buf[4]  = 0xff;
+	buf[5]  = 0x12;		/* link local scope */
+	buf[6]  = 0x40;		/* IPv4 signature */
+	buf[7]  = 0x1b;
+	buf[8]  = 0;		/* P_Key */
+	buf[9]  = 0;
+	buf[10] = 0;
+	buf[11] = 0;
+	buf[12] = 0;
+	buf[13] = 0;
+	buf[14] = 0;
+	buf[15] = 0;
+	buf[19] = addr & 0xff;
+	addr  >>= 8;
+	buf[18] = addr & 0xff;
+	addr  >>= 8;
+	buf[17] = addr & 0xff;
+	addr  >>= 8;
+	buf[16] = addr & 0x0f;
+}
+
 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 #include <linux/ipv6.h>
 #endif

net/ipv4/arp.c

@@ -213,6 +213,9 @@ int arp_mc_map(u32 addr, u8 *haddr, struct net_device *dev, int dir)
 	case ARPHRD_IEEE802_TR:
 		ip_tr_mc_map(addr, haddr);
 		return 0;
+	case ARPHRD_INFINIBAND:
+		ip_ib_mc_map(addr, haddr);
+		return 0;
 	default:
 		if (dir) {
 			memcpy(haddr, dev->broadcast, dev->addr_len);