ipvlan: Initial check-in of the IPVLAN driver.

This driver is very similar to the macvlan driver except that it
uses L3 on the frame to determine the logical interface while
functioning as packet dispatcher. It inherits L2 of the master
device hence the packets on wire will have the same L2 for all
the packets originating from all virtual devices off of the same
master device.

This driver was developed keeping the namespace use-case in
mind. Hence most of the examples given here take that as the
base setup where main-device belongs to the default-ns and
virtual devices are assigned to the additional namespaces.

The device operates in two different modes and the difference
in these two modes in primarily in the TX side.

(a) L2 mode : In this mode, the device behaves as a L2 device.
TX processing upto L2 happens on the stack of the virtual device
associated with (namespace). Packets are switched after that
into the main device (default-ns) and queued for xmit.

RX processing is simple and all multicast, broadcast (if
applicable), and unicast belonging to the address(es) are
delivered to the virtual devices.

(b) L3 mode : In this mode, the device behaves like a L3 device.
TX processing upto L3 happens on the stack of the virtual device
associated with (namespace). Packets are switched to the
main-device (default-ns) for the L2 processing. Hence the routing
table of the default-ns will be used in this mode.

RX processins is somewhat similar to the L2 mode except that in
this mode only Unicast packets are delivered to the virtual device
while main-dev will handle all other packets.

The devices can be added using the "ip" command from the iproute2
package -

	ip link add link <master> <virtual> type ipvlan mode [ l2 | l3 ]

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Maciej Żenczykowski <maze@google.com>
Cc: Laurent Chavey <chavey@google.com>
Cc: Tim Hockin <thockin@google.com>
Cc: Brandon Philips <brandon.philips@coreos.com>
Cc: Pavel Emelianov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 607 insertions, 0 deletions

diff --git a/drivers/net/ipvlan/ipvlan_core.c b/drivers/net/ipvlan/ipvlan_core.c
new file mode 100644
index 000000000000..a14d87783245
--- /dev/null
+++ b/drivers/net/ipvlan/ipvlan_core.c
@@ -0,0 +1,607 @@
+/* Copyright (c) 2014 Mahesh Bandewar <maheshb@google.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ */
+
+#include "ipvlan.h"
+
+static u32 ipvlan_jhash_secret;
+
+void ipvlan_init_secret(void)
+{
+	net_get_random_once(&ipvlan_jhash_secret, sizeof(ipvlan_jhash_secret));
+}
+
+static void ipvlan_count_rx(const struct ipvl_dev *ipvlan,
+			    unsigned int len, bool success, bool mcast)
+{
+	if (!ipvlan)
+		return;
+
+	if (likely(success)) {
+		struct ipvl_pcpu_stats *pcptr;
+
+		pcptr = this_cpu_ptr(ipvlan->pcpu_stats);
+		u64_stats_update_begin(&pcptr->syncp);
+		pcptr->rx_pkts++;
+		pcptr->rx_bytes += len;
+		if (mcast)
+			pcptr->rx_mcast++;
+		u64_stats_update_end(&pcptr->syncp);
+	} else {
+		this_cpu_inc(ipvlan->pcpu_stats->rx_errs);
+	}
+}
+
+static u8 ipvlan_get_v6_hash(const void *iaddr)
+{
+	const struct in6_addr *ip6_addr = iaddr;
+
+	return __ipv6_addr_jhash(ip6_addr, ipvlan_jhash_secret) &
+	       IPVLAN_HASH_MASK;
+}
+
+static u8 ipvlan_get_v4_hash(const void *iaddr)
+{
+	const struct in_addr *ip4_addr = iaddr;
+
+	return jhash_1word(ip4_addr->s_addr, ipvlan_jhash_secret) &
+	       IPVLAN_HASH_MASK;
+}
+
+struct ipvl_addr *ipvlan_ht_addr_lookup(const struct ipvl_port *port,
+					const void *iaddr, bool is_v6)
+{
+	struct ipvl_addr *addr;
+	u8 hash;
+
+	hash = is_v6 ? ipvlan_get_v6_hash(iaddr) :
+	       ipvlan_get_v4_hash(iaddr);
+	hlist_for_each_entry_rcu(addr, &port->hlhead[hash], hlnode) {
+		if (is_v6 && addr->atype == IPVL_IPV6 &&
+		    ipv6_addr_equal(&addr->ip6addr, iaddr))
+			return addr;
+		else if (!is_v6 && addr->atype == IPVL_IPV4 &&
+			 addr->ip4addr.s_addr ==
+				((struct in_addr *)iaddr)->s_addr)
+			return addr;
+	}
+	return NULL;
+}
+
+void ipvlan_ht_addr_add(struct ipvl_dev *ipvlan, struct ipvl_addr *addr)
+{
+	struct ipvl_port *port = ipvlan->port;
+	u8 hash;
+
+	hash = (addr->atype == IPVL_IPV6) ?
+	       ipvlan_get_v6_hash(&addr->ip6addr) :
+	       ipvlan_get_v4_hash(&addr->ip4addr);
+	hlist_add_head_rcu(&addr->hlnode, &port->hlhead[hash]);
+}
+
+void ipvlan_ht_addr_del(struct ipvl_addr *addr, bool sync)
+{
+	hlist_del_rcu(&addr->hlnode);
+	if (sync)
+		synchronize_rcu();
+}
+
+bool ipvlan_addr_busy(struct ipvl_dev *ipvlan, void *iaddr, bool is_v6)
+{
+	struct ipvl_port *port = ipvlan->port;
+	struct ipvl_addr *addr;
+
+	list_for_each_entry(addr, &ipvlan->addrs, anode) {
+		if ((is_v6 && addr->atype == IPVL_IPV6 &&
+		    ipv6_addr_equal(&addr->ip6addr, iaddr)) ||
+		    (!is_v6 && addr->atype == IPVL_IPV4 &&
+		    addr->ip4addr.s_addr == ((struct in_addr *)iaddr)->s_addr))
+			return true;
+	}
+
+	if (ipvlan_ht_addr_lookup(port, iaddr, is_v6))
+		return true;
+
+	return false;
+}
+
+static void *ipvlan_get_L3_hdr(struct sk_buff *skb, int *type)
+{
+	void *lyr3h = NULL;
+
+	switch (skb->protocol) {
+	case htons(ETH_P_ARP): {
+		struct arphdr *arph;
+
+		if (unlikely(!pskb_may_pull(skb, sizeof(*arph))))
+			return NULL;
+
+		arph = arp_hdr(skb);
+		*type = IPVL_ARP;
+		lyr3h = arph;
+		break;
+	}
+	case htons(ETH_P_IP): {
+		u32 pktlen;
+		struct iphdr *ip4h;
+
+		if (unlikely(!pskb_may_pull(skb, sizeof(*ip4h))))
+			return NULL;
+
+		ip4h = ip_hdr(skb);
+		pktlen = ntohs(ip4h->tot_len);
+		if (ip4h->ihl < 5 || ip4h->version != 4)
+			return NULL;
+		if (skb->len < pktlen || pktlen < (ip4h->ihl * 4))
+			return NULL;
+
+		*type = IPVL_IPV4;
+		lyr3h = ip4h;
+		break;
+	}
+	case htons(ETH_P_IPV6): {
+		struct ipv6hdr *ip6h;
+
+		if (unlikely(!pskb_may_pull(skb, sizeof(*ip6h))))
+			return NULL;
+
+		ip6h = ipv6_hdr(skb);
+		if (ip6h->version != 6)
+			return NULL;
+
+		*type = IPVL_IPV6;
+		lyr3h = ip6h;
+		/* Only Neighbour Solicitation pkts need different treatment */
+		if (ipv6_addr_any(&ip6h->saddr) &&
+		    ip6h->nexthdr == NEXTHDR_ICMP) {
+			*type = IPVL_ICMPV6;
+			lyr3h = ip6h + 1;
+		}
+		break;
+	}
+	default:
+		return NULL;
+	}
+
+	return lyr3h;
+}
+
+unsigned int ipvlan_mac_hash(const unsigned char *addr)
+{
+	u32 hash = jhash_1word(__get_unaligned_cpu32(addr+2),
+			       ipvlan_jhash_secret);
+
+	return hash & IPVLAN_MAC_FILTER_MASK;
+}
+
+static void ipvlan_multicast_frame(struct ipvl_port *port, struct sk_buff *skb,
+				   const struct ipvl_dev *in_dev, bool local)
+{
+	struct ethhdr *eth = eth_hdr(skb);
+	struct ipvl_dev *ipvlan;
+	struct sk_buff *nskb;
+	unsigned int len;
+	unsigned int mac_hash;
+	int ret;
+
+	if (skb->protocol == htons(ETH_P_PAUSE))
+		return;
+
+	list_for_each_entry(ipvlan, &port->ipvlans, pnode) {
+		if (local && (ipvlan == in_dev))
+			continue;
+
+		mac_hash = ipvlan_mac_hash(eth->h_dest);
+		if (!test_bit(mac_hash, ipvlan->mac_filters))
+			continue;
+
+		ret = NET_RX_DROP;
+		len = skb->len + ETH_HLEN;
+		nskb = skb_clone(skb, GFP_ATOMIC);
+		if (!nskb)
+			goto mcast_acct;
+
+		if (ether_addr_equal(eth->h_dest, ipvlan->phy_dev->broadcast))
+			nskb->pkt_type = PACKET_BROADCAST;
+		else
+			nskb->pkt_type = PACKET_MULTICAST;
+
+		nskb->dev = ipvlan->dev;
+		if (local)
+			ret = dev_forward_skb(ipvlan->dev, nskb);
+		else
+			ret = netif_rx(nskb);
+mcast_acct:
+		ipvlan_count_rx(ipvlan, len, ret == NET_RX_SUCCESS, true);
+	}
+
+	/* Locally generated? ...Forward a copy to the main-device as
+	 * well. On the RX side we'll ignore it (wont give it to any
+	 * of the virtual devices.
+	 */
+	if (local) {
+		nskb = skb_clone(skb, GFP_ATOMIC);
+		if (nskb) {
+			if (ether_addr_equal(eth->h_dest, port->dev->broadcast))
+				nskb->pkt_type = PACKET_BROADCAST;
+			else
+				nskb->pkt_type = PACKET_MULTICAST;
+
+			dev_forward_skb(port->dev, nskb);
+		}
+	}
+}
+
+static int ipvlan_rcv_frame(struct ipvl_addr *addr, struct sk_buff *skb,
+			    bool local)
+{
+	struct ipvl_dev *ipvlan = addr->master;
+	struct net_device *dev = ipvlan->dev;
+	unsigned int len;
+	rx_handler_result_t ret = RX_HANDLER_CONSUMED;
+	bool success = false;
+
+	len = skb->len + ETH_HLEN;
+	if (unlikely(!(dev->flags & IFF_UP))) {
+		kfree_skb(skb);
+		goto out;
+	}
+
+	skb = skb_share_check(skb, GFP_ATOMIC);
+	if (!skb)
+		goto out;
+
+	skb->dev = dev;
+	skb->pkt_type = PACKET_HOST;
+
+	if (local) {
+		if (dev_forward_skb(ipvlan->dev, skb) == NET_RX_SUCCESS)
+			success = true;
+	} else {
+		ret = RX_HANDLER_ANOTHER;
+		success = true;
+	}
+
+out:
+	ipvlan_count_rx(ipvlan, len, success, false);
+	return ret;
+}
+
+static struct ipvl_addr *ipvlan_addr_lookup(struct ipvl_port *port,
+					    void *lyr3h, int addr_type,
+					    bool use_dest)
+{
+	struct ipvl_addr *addr = NULL;
+
+	if (addr_type == IPVL_IPV6) {
+		struct ipv6hdr *ip6h;
+		struct in6_addr *i6addr;
+
+		ip6h = (struct ipv6hdr *)lyr3h;
+		i6addr = use_dest ? &ip6h->daddr : &ip6h->saddr;
+		addr = ipvlan_ht_addr_lookup(port, i6addr, true);
+	} else if (addr_type == IPVL_ICMPV6) {
+		struct nd_msg *ndmh;
+		struct in6_addr *i6addr;
+
+		/* Make sure that the NeighborSolicitation ICMPv6 packets
+		 * are handled to avoid DAD issue.
+		 */
+		ndmh = (struct nd_msg *)lyr3h;
+		if (ndmh->icmph.icmp6_type == NDISC_NEIGHBOUR_SOLICITATION) {
+			i6addr = &ndmh->target;
+			addr = ipvlan_ht_addr_lookup(port, i6addr, true);
+		}
+	} else if (addr_type == IPVL_IPV4) {
+		struct iphdr *ip4h;
+		__be32 *i4addr;
+
+		ip4h = (struct iphdr *)lyr3h;
+		i4addr = use_dest ? &ip4h->daddr : &ip4h->saddr;
+		addr = ipvlan_ht_addr_lookup(port, i4addr, false);
+	} else if (addr_type == IPVL_ARP) {
+		struct arphdr *arph;
+		unsigned char *arp_ptr;
+		__be32 dip;
+
+		arph = (struct arphdr *)lyr3h;
+		arp_ptr = (unsigned char *)(arph + 1);
+		if (use_dest)
+			arp_ptr += (2 * port->dev->addr_len) + 4;
+		else
+			arp_ptr += port->dev->addr_len;
+
+		memcpy(&dip, arp_ptr, 4);
+		addr = ipvlan_ht_addr_lookup(port, &dip, false);
+	}
+
+	return addr;
+}
+
+static int ipvlan_process_v4_outbound(struct sk_buff *skb)
+{
+	const struct iphdr *ip4h = ip_hdr(skb);
+	struct net_device *dev = skb->dev;
+	struct rtable *rt;
+	int err, ret = NET_XMIT_DROP;
+	struct flowi4 fl4 = {
+		.flowi4_oif = dev->iflink,
+		.flowi4_tos = RT_TOS(ip4h->tos),
+		.flowi4_flags = FLOWI_FLAG_ANYSRC,
+		.daddr = ip4h->daddr,
+		.saddr = ip4h->saddr,
+	};
+
+	rt = ip_route_output_flow(dev_net(dev), &fl4, NULL);
+	if (IS_ERR(rt))
+		goto err;
+
+	if (rt->rt_type != RTN_UNICAST && rt->rt_type != RTN_LOCAL) {
+		ip_rt_put(rt);
+		goto err;
+	}
+	skb_dst_drop(skb);
+	skb_dst_set(skb, &rt->dst);
+	err = ip_local_out(skb);
+	if (unlikely(net_xmit_eval(err)))
+		dev->stats.tx_errors++;
+	else
+		ret = NET_XMIT_SUCCESS;
+	goto out;
+err:
+	dev->stats.tx_errors++;
+	kfree_skb(skb);
+out:
+	return ret;
+}
+
+static int ipvlan_process_v6_outbound(struct sk_buff *skb)
+{
+	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
+	struct net_device *dev = skb->dev;
+	struct dst_entry *dst;
+	int err, ret = NET_XMIT_DROP;
+	struct flowi6 fl6 = {
+		.flowi6_iif = skb->dev->ifindex,
+		.daddr = ip6h->daddr,
+		.saddr = ip6h->saddr,
+		.flowi6_flags = FLOWI_FLAG_ANYSRC,
+		.flowlabel = ip6_flowinfo(ip6h),
+		.flowi6_mark = skb->mark,
+		.flowi6_proto = ip6h->nexthdr,
+	};
+
+	dst = ip6_route_output(dev_net(dev), NULL, &fl6);
+	if (IS_ERR(dst))
+		goto err;
+
+	skb_dst_drop(skb);
+	skb_dst_set(skb, dst);
+	err = ip6_local_out(skb);
+	if (unlikely(net_xmit_eval(err)))
+		dev->stats.tx_errors++;
+	else
+		ret = NET_XMIT_SUCCESS;
+	goto out;
+err:
+	dev->stats.tx_errors++;
+	kfree_skb(skb);
+out:
+	return ret;
+}
+
+static int ipvlan_process_outbound(struct sk_buff *skb,
+				   const struct ipvl_dev *ipvlan)
+{
+	struct ethhdr *ethh = eth_hdr(skb);
+	int ret = NET_XMIT_DROP;
+
+	/* In this mode we dont care about multicast and broadcast traffic */
+	if (is_multicast_ether_addr(ethh->h_dest)) {
+		pr_warn_ratelimited("Dropped {multi|broad}cast of type= [%x]\n",
+				    ntohs(skb->protocol));
+		kfree_skb(skb);
+		goto out;
+	}
+
+	/* The ipvlan is a pseudo-L2 device, so the packets that we receive
+	 * will have L2; which need to discarded and processed further
+	 * in the net-ns of the main-device.
+	 */
+	if (skb_mac_header_was_set(skb)) {
+		skb_pull(skb, sizeof(*ethh));
+		skb->mac_header = (typeof(skb->mac_header))~0U;
+		skb_reset_network_header(skb);
+	}
+
+	if (skb->protocol == htons(ETH_P_IPV6))
+		ret = ipvlan_process_v6_outbound(skb);
+	else if (skb->protocol == htons(ETH_P_IP))
+		ret = ipvlan_process_v4_outbound(skb);
+	else {
+		pr_warn_ratelimited("Dropped outbound packet type=%x\n",
+				    ntohs(skb->protocol));
+		kfree_skb(skb);
+	}
+out:
+	return ret;
+}
+
+static int ipvlan_xmit_mode_l3(struct sk_buff *skb, struct net_device *dev)
+{
+	const struct ipvl_dev *ipvlan = netdev_priv(dev);
+	void *lyr3h;
+	struct ipvl_addr *addr;
+	int addr_type;
+
+	lyr3h = ipvlan_get_L3_hdr(skb, &addr_type);
+	if (!lyr3h)
+		goto out;
+
+	addr = ipvlan_addr_lookup(ipvlan->port, lyr3h, addr_type, true);
+	if (addr)
+		return ipvlan_rcv_frame(addr, skb, true);
+
+out:
+	skb->dev = ipvlan->phy_dev;
+	return ipvlan_process_outbound(skb, ipvlan);
+}
+
+static int ipvlan_xmit_mode_l2(struct sk_buff *skb, struct net_device *dev)
+{
+	const struct ipvl_dev *ipvlan = netdev_priv(dev);
+	struct ethhdr *eth = eth_hdr(skb);
+	struct ipvl_addr *addr;
+	void *lyr3h;
+	int addr_type;
+
+	if (ether_addr_equal(eth->h_dest, eth->h_source)) {
+		lyr3h = ipvlan_get_L3_hdr(skb, &addr_type);
+		if (lyr3h) {
+			addr = ipvlan_addr_lookup(ipvlan->port, lyr3h, addr_type, true);
+			if (addr)
+				return ipvlan_rcv_frame(addr, skb, true);
+		}
+		skb = skb_share_check(skb, GFP_ATOMIC);
+		if (!skb)
+			return NET_XMIT_DROP;
+
+		/* Packet definitely does not belong to any of the
+		 * virtual devices, but the dest is local. So forward
+		 * the skb for the main-dev. At the RX side we just return
+		 * RX_PASS for it to be processed further on the stack.
+		 */
+		return dev_forward_skb(ipvlan->phy_dev, skb);
+
+	} else if (is_multicast_ether_addr(eth->h_dest)) {
+		u8 ip_summed = skb->ip_summed;
+
+		skb->ip_summed = CHECKSUM_UNNECESSARY;
+		ipvlan_multicast_frame(ipvlan->port, skb, ipvlan, true);
+		skb->ip_summed = ip_summed;
+	}
+
+	skb->dev = ipvlan->phy_dev;
+	return dev_queue_xmit(skb);
+}
+
+int ipvlan_queue_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct ipvl_dev *ipvlan = netdev_priv(dev);
+	struct ipvl_port *port = ipvlan_port_get_rcu(ipvlan->phy_dev);
+
+	if (!port)
+		goto out;
+
+	if (unlikely(!pskb_may_pull(skb, sizeof(struct ethhdr))))
+		goto out;
+
+	switch(port->mode) {
+	case IPVLAN_MODE_L2:
+		return ipvlan_xmit_mode_l2(skb, dev);
+	case IPVLAN_MODE_L3:
+		return ipvlan_xmit_mode_l3(skb, dev);
+	}
+
+	/* Should not reach here */
+	WARN_ONCE(true, "ipvlan_queue_xmit() called for mode = [%hx]\n",
+			  port->mode);
+out:
+	kfree_skb(skb);
+	return NET_XMIT_DROP;
+}
+
+static bool ipvlan_external_frame(struct sk_buff *skb, struct ipvl_port *port)
+{
+	struct ethhdr *eth = eth_hdr(skb);
+	struct ipvl_addr *addr;
+	void *lyr3h;
+	int addr_type;
+
+	if (ether_addr_equal(eth->h_source, skb->dev->dev_addr)) {
+		lyr3h = ipvlan_get_L3_hdr(skb, &addr_type);
+		if (!lyr3h)
+			return true;
+
+		addr = ipvlan_addr_lookup(port, lyr3h, addr_type, false);
+		if (addr)
+			return false;
+	}
+
+	return true;
+}
+
+static rx_handler_result_t ipvlan_handle_mode_l3(struct sk_buff **pskb,
+						 struct ipvl_port *port)
+{
+	void *lyr3h;
+	int addr_type;
+	struct ipvl_addr *addr;
+	struct sk_buff *skb = *pskb;
+	rx_handler_result_t ret = RX_HANDLER_PASS;
+
+	lyr3h = ipvlan_get_L3_hdr(skb, &addr_type);
+	if (!lyr3h)
+		goto out;
+
+	addr = ipvlan_addr_lookup(port, lyr3h, addr_type, true);
+	if (addr)
+		ret = ipvlan_rcv_frame(addr, skb, false);
+
+out:
+	return ret;
+}
+
+static rx_handler_result_t ipvlan_handle_mode_l2(struct sk_buff **pskb,
+						 struct ipvl_port *port)
+{
+	struct sk_buff *skb = *pskb;
+	struct ethhdr *eth = eth_hdr(skb);
+	rx_handler_result_t ret = RX_HANDLER_PASS;
+	void *lyr3h;
+	int addr_type;
+
+	if (is_multicast_ether_addr(eth->h_dest)) {
+		if (ipvlan_external_frame(skb, port))
+			ipvlan_multicast_frame(port, skb, NULL, false);
+	} else {
+		struct ipvl_addr *addr;
+
+		lyr3h = ipvlan_get_L3_hdr(skb, &addr_type);
+		if (!lyr3h)
+			return ret;
+
+		addr = ipvlan_addr_lookup(port, lyr3h, addr_type, true);
+		if (addr)
+			ret = ipvlan_rcv_frame(addr, skb, false);
+	}
+
+	return ret;
+}
+
+rx_handler_result_t ipvlan_handle_frame(struct sk_buff **pskb)
+{
+	struct sk_buff *skb = *pskb;
+	struct ipvl_port *port = ipvlan_port_get_rcu(skb->dev);
+
+	if (!port)
+		return RX_HANDLER_PASS;
+
+	switch (port->mode) {
+	case IPVLAN_MODE_L2:
+		return ipvlan_handle_mode_l2(pskb, port);
+	case IPVLAN_MODE_L3:
+		return ipvlan_handle_mode_l3(pskb, port);
+	}
+
+	/* Should not reach here */
+	WARN_ONCE(true, "ipvlan_handle_frame() called for mode = [%hx]\n",
+			  port->mode);
+	kfree_skb(skb);
+	return NET_RX_DROP;
+}