1 files changed, 335 insertions, 0 deletions
diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
new file mode 100644
index 000000000..f2ef75c7c
--- /dev/null
+++ b/net/bridge/br_forward.c
@@ -0,0 +1,335 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	Forwarding decision
+ *	Linux ethernet bridge
+ *
+ *	Authors:
+ *	Lennert Buytenhek		<buytenh@gnu.org>
+ */
+
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/netdevice.h>
+#include <linux/netpoll.h>
+#include <linux/skbuff.h>
+#include <linux/if_vlan.h>
+#include <linux/netfilter_bridge.h>
+#include "br_private.h"
+
+/* Don't forward packets to originating port or forwarding disabled */
+static inline int should_deliver(const struct net_bridge_port *p,
+				 const struct sk_buff *skb)
+{
+	struct net_bridge_vlan_group *vg;
+
+	vg = nbp_vlan_group_rcu(p);
+	return ((p->flags & BR_HAIRPIN_MODE) || skb->dev != p->dev) &&
+		p->state == BR_STATE_FORWARDING && br_allowed_egress(vg, skb) &&
+		nbp_switchdev_allowed_egress(p, skb) &&
+		!br_skb_isolated(p, skb);
+}
+
+int br_dev_queue_push_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	skb_push(skb, ETH_HLEN);
+	if (!is_skb_forwardable(skb->dev, skb))
+		goto drop;
+
+	br_drop_fake_rtable(skb);
+
+	if (skb->ip_summed == CHECKSUM_PARTIAL &&
+	    (skb->protocol == htons(ETH_P_8021Q) ||
+	     skb->protocol == htons(ETH_P_8021AD))) {
+		int depth;
+
+		if (!vlan_get_protocol_and_depth(skb, skb->protocol, &depth))
+			goto drop;
+
+		skb_set_network_header(skb, depth);
+	}
+
+	dev_queue_xmit(skb);
+
+	return 0;
+
+drop:
+	kfree_skb(skb);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);
+
+int br_forward_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	skb->tstamp = 0;
+	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING,
+		       net, sk, skb, NULL, skb->dev,
+		       br_dev_queue_push_xmit);
+
+}
+EXPORT_SYMBOL_GPL(br_forward_finish);
+
+static void __br_forward(const struct net_bridge_port *to,
+			 struct sk_buff *skb, bool local_orig)
+{
+	struct net_bridge_vlan_group *vg;
+	struct net_device *indev;
+	struct net *net;
+	int br_hook;
+
+	vg = nbp_vlan_group_rcu(to);
+	skb = br_handle_vlan(to->br, to, vg, skb);
+	if (!skb)
+		return;
+
+	indev = skb->dev;
+	skb->dev = to->dev;
+	if (!local_orig) {
+		if (skb_warn_if_lro(skb)) {
+			kfree_skb(skb);
+			return;
+		}
+		br_hook = NF_BR_FORWARD;
+		skb_forward_csum(skb);
+		net = dev_net(indev);
+	} else {
+		if (unlikely(netpoll_tx_running(to->br->dev))) {
+			skb_push(skb, ETH_HLEN);
+			if (!is_skb_forwardable(skb->dev, skb))
+				kfree_skb(skb);
+			else
+				br_netpoll_send_skb(to, skb);
+			return;
+		}
+		br_hook = NF_BR_LOCAL_OUT;
+		net = dev_net(skb->dev);
+		indev = NULL;
+	}
+
+	NF_HOOK(NFPROTO_BRIDGE, br_hook,
+		net, NULL, skb, indev, skb->dev,
+		br_forward_finish);
+}
+
+static int deliver_clone(const struct net_bridge_port *prev,
+			 struct sk_buff *skb, bool local_orig)
+{
+	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
+
+	skb = skb_clone(skb, GFP_ATOMIC);
+	if (!skb) {
+		DEV_STATS_INC(dev, tx_dropped);
+		return -ENOMEM;
+	}
+
+	__br_forward(prev, skb, local_orig);
+	return 0;
+}
+
+/**
+ * br_forward - forward a packet to a specific port
+ * @to: destination port
+ * @skb: packet being forwarded
+ * @local_rcv: packet will be received locally after forwarding
+ * @local_orig: packet is locally originated
+ *
+ * Should be called with rcu_read_lock.
+ */
+void br_forward(const struct net_bridge_port *to,
+		struct sk_buff *skb, bool local_rcv, bool local_orig)
+{
+	if (unlikely(!to))
+		goto out;
+
+	/* redirect to backup link if the destination port is down */
+	if (rcu_access_pointer(to->backup_port) && !netif_carrier_ok(to->dev)) {
+		struct net_bridge_port *backup_port;
+
+		backup_port = rcu_dereference(to->backup_port);
+		if (unlikely(!backup_port))
+			goto out;
+		to = backup_port;
+	}
+
+	if (should_deliver(to, skb)) {
+		if (local_rcv)
+			deliver_clone(to, skb, local_orig);
+		else
+			__br_forward(to, skb, local_orig);
+		return;
+	}
+
+out:
+	if (!local_rcv)
+		kfree_skb(skb);
+}
+EXPORT_SYMBOL_GPL(br_forward);
+
+static struct net_bridge_port *maybe_deliver(
+	struct net_bridge_port *prev, struct net_bridge_port *p,
+	struct sk_buff *skb, bool local_orig)
+{
+	u8 igmp_type = br_multicast_igmp_type(skb);
+	int err;
+
+	if (!should_deliver(p, skb))
+		return prev;
+
+	if (!prev)
+		goto out;
+
+	err = deliver_clone(prev, skb, local_orig);
+	if (err)
+		return ERR_PTR(err);
+out:
+	br_multicast_count(p->br, p, skb, igmp_type, BR_MCAST_DIR_TX);
+
+	return p;
+}
+
+/* called under rcu_read_lock */
+void br_flood(struct net_bridge *br, struct sk_buff *skb,
+	      enum br_pkt_type pkt_type, bool local_rcv, bool local_orig)
+{
+	struct net_bridge_port *prev = NULL;
+	struct net_bridge_port *p;
+
+	list_for_each_entry_rcu(p, &br->port_list, list) {
+		/* Do not flood unicast traffic to ports that turn it off, nor
+		 * other traffic if flood off, except for traffic we originate
+		 */
+		switch (pkt_type) {
+		case BR_PKT_UNICAST:
+			if (!(p->flags & BR_FLOOD))
+				continue;
+			break;
+		case BR_PKT_MULTICAST:
+			if (!(p->flags & BR_MCAST_FLOOD) && skb->dev != br->dev)
+				continue;
+			break;
+		case BR_PKT_BROADCAST:
+			if (!(p->flags & BR_BCAST_FLOOD) && skb->dev != br->dev)
+				continue;
+			break;
+		}
+
+		/* Do not flood to ports that enable proxy ARP */
+		if (p->flags & BR_PROXYARP)
+			continue;
+		if ((p->flags & (BR_PROXYARP_WIFI | BR_NEIGH_SUPPRESS)) &&
+		    BR_INPUT_SKB_CB(skb)->proxyarp_replied)
+			continue;
+
+		prev = maybe_deliver(prev, p, skb, local_orig);
+		if (IS_ERR(prev))
+			goto out;
+	}
+
+	if (!prev)
+		goto out;
+
+	if (local_rcv)
+		deliver_clone(prev, skb, local_orig);
+	else
+		__br_forward(prev, skb, local_orig);
+	return;
+
+out:
+	if (!local_rcv)
+		kfree_skb(skb);
+}
+
+#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
+static void maybe_deliver_addr(struct net_bridge_port *p, struct sk_buff *skb,
+			       const unsigned char *addr, bool local_orig)
+{
+	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
+	const unsigned char *src = eth_hdr(skb)->h_source;
+
+	if (!should_deliver(p, skb))
+		return;
+
+	/* Even with hairpin, no soliloquies - prevent breaking IPv6 DAD */
+	if (skb->dev == p->dev && ether_addr_equal(src, addr))
+		return;
+
+	skb = skb_copy(skb, GFP_ATOMIC);
+	if (!skb) {
+		DEV_STATS_INC(dev, tx_dropped);
+		return;
+	}
+
+	if (!is_broadcast_ether_addr(addr))
+		memcpy(eth_hdr(skb)->h_dest, addr, ETH_ALEN);
+
+	__br_forward(p, skb, local_orig);
+}
+
+/* called with rcu_read_lock */
+void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
+			struct sk_buff *skb,
+			bool local_rcv, bool local_orig)
+{
+	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
+	struct net_bridge *br = netdev_priv(dev);
+	struct net_bridge_port *prev = NULL;
+	struct net_bridge_port_group *p;
+	bool allow_mode_include = true;
+	struct hlist_node *rp;
+
+	rp = rcu_dereference(hlist_first_rcu(&br->router_list));
+	if (mdst) {
+		p = rcu_dereference(mdst->ports);
+		if (br_multicast_should_handle_mode(br, mdst->addr.proto) &&
+		    br_multicast_is_star_g(&mdst->addr))
+			allow_mode_include = false;
+	} else {
+		p = NULL;
+	}
+
+	while (p || rp) {
+		struct net_bridge_port *port, *lport, *rport;
+
+		lport = p ? p->key.port : NULL;
+		rport = hlist_entry_safe(rp, struct net_bridge_port, rlist);
+
+		if ((unsigned long)lport > (unsigned long)rport) {
+			port = lport;
+
+			if (port->flags & BR_MULTICAST_TO_UNICAST) {
+				maybe_deliver_addr(lport, skb, p->eth_addr,
+						   local_orig);
+				goto delivered;
+			}
+			if ((!allow_mode_include &&
+			     p->filter_mode == MCAST_INCLUDE) ||
+			    (p->flags & MDB_PG_FLAGS_BLOCKED))
+				goto delivered;
+		} else {
+			port = rport;
+		}
+
+		prev = maybe_deliver(prev, port, skb, local_orig);
+		if (IS_ERR(prev))
+			goto out;
+delivered:
+		if ((unsigned long)lport >= (unsigned long)port)
+			p = rcu_dereference(p->next);
+		if ((unsigned long)rport >= (unsigned long)port)
+			rp = rcu_dereference(hlist_next_rcu(rp));
+	}
+
+	if (!prev)
+		goto out;
+
+	if (local_rcv)
+		deliver_clone(prev, skb, local_orig);
+	else
+		__br_forward(prev, skb, local_orig);
+	return;
+
+out:
+	if (!local_rcv)
+		kfree_skb(skb);
+}
+#endif