Initial import

1 files changed, 315 insertions, 0 deletions

diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
new file mode 100644
index 000000000..f921a5dce
--- /dev/null
+++ b/net/bridge/br_input.c
@@ -0,0 +1,315 @@
+/*
+ *	Handle incoming frames
+ *	Linux ethernet bridge
+ *
+ *	Authors:
+ *	Lennert Buytenhek		<buytenh@gnu.org>
+ *
+ *	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 <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/netfilter_bridge.h>
+#include <linux/neighbour.h>
+#include <net/arp.h>
+#include <linux/export.h>
+#include <linux/rculist.h>
+#include "br_private.h"
+
+/* Hook for brouter */
+br_should_route_hook_t __rcu *br_should_route_hook __read_mostly;
+EXPORT_SYMBOL(br_should_route_hook);
+
+static int br_pass_frame_up(struct sk_buff *skb)
+{
+	struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev;
+	struct net_bridge *br = netdev_priv(brdev);
+	struct pcpu_sw_netstats *brstats = this_cpu_ptr(br->stats);
+	struct net_port_vlans *pv;
+
+	u64_stats_update_begin(&brstats->syncp);
+	brstats->rx_packets++;
+	brstats->rx_bytes += skb->len;
+	u64_stats_update_end(&brstats->syncp);
+
+	/* Bridge is just like any other port.  Make sure the
+	 * packet is allowed except in promisc modue when someone
+	 * may be running packet capture.
+	 */
+	pv = br_get_vlan_info(br);
+	if (!(brdev->flags & IFF_PROMISC) &&
+	    !br_allowed_egress(br, pv, skb)) {
+		kfree_skb(skb);
+		return NET_RX_DROP;
+	}
+
+	indev = skb->dev;
+	skb->dev = brdev;
+	skb = br_handle_vlan(br, pv, skb);
+	if (!skb)
+		return NET_RX_DROP;
+
+	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, NULL, skb,
+		       indev, NULL,
+		       netif_receive_skb_sk);
+}
+
+static void br_do_proxy_arp(struct sk_buff *skb, struct net_bridge *br,
+			    u16 vid, struct net_bridge_port *p)
+{
+	struct net_device *dev = br->dev;
+	struct neighbour *n;
+	struct arphdr *parp;
+	u8 *arpptr, *sha;
+	__be32 sip, tip;
+
+	BR_INPUT_SKB_CB(skb)->proxyarp_replied = false;
+
+	if (dev->flags & IFF_NOARP)
+		return;
+
+	if (!pskb_may_pull(skb, arp_hdr_len(dev))) {
+		dev->stats.tx_dropped++;
+		return;
+	}
+	parp = arp_hdr(skb);
+
+	if (parp->ar_pro != htons(ETH_P_IP) ||
+	    parp->ar_op != htons(ARPOP_REQUEST) ||
+	    parp->ar_hln != dev->addr_len ||
+	    parp->ar_pln != 4)
+		return;
+
+	arpptr = (u8 *)parp + sizeof(struct arphdr);
+	sha = arpptr;
+	arpptr += dev->addr_len;	/* sha */
+	memcpy(&sip, arpptr, sizeof(sip));
+	arpptr += sizeof(sip);
+	arpptr += dev->addr_len;	/* tha */
+	memcpy(&tip, arpptr, sizeof(tip));
+
+	if (ipv4_is_loopback(tip) ||
+	    ipv4_is_multicast(tip))
+		return;
+
+	n = neigh_lookup(&arp_tbl, &tip, dev);
+	if (n) {
+		struct net_bridge_fdb_entry *f;
+
+		if (!(n->nud_state & NUD_VALID)) {
+			neigh_release(n);
+			return;
+		}
+
+		f = __br_fdb_get(br, n->ha, vid);
+		if (f && ((p->flags & BR_PROXYARP) ||
+			  (f->dst && (f->dst->flags & BR_PROXYARP_WIFI)))) {
+			arp_send(ARPOP_REPLY, ETH_P_ARP, sip, skb->dev, tip,
+				 sha, n->ha, sha);
+			BR_INPUT_SKB_CB(skb)->proxyarp_replied = true;
+		}
+
+		neigh_release(n);
+	}
+}
+
+/* note: already called with rcu_read_lock */
+int br_handle_frame_finish(struct sock *sk, struct sk_buff *skb)
+{
+	const unsigned char *dest = eth_hdr(skb)->h_dest;
+	struct net_bridge_port *p = br_port_get_rcu(skb->dev);
+	struct net_bridge *br;
+	struct net_bridge_fdb_entry *dst;
+	struct net_bridge_mdb_entry *mdst;
+	struct sk_buff *skb2;
+	bool unicast = true;
+	u16 vid = 0;
+
+	if (!p || p->state == BR_STATE_DISABLED)
+		goto drop;
+
+	if (!br_allowed_ingress(p->br, nbp_get_vlan_info(p), skb, &vid))
+		goto out;
+
+	/* insert into forwarding database after filtering to avoid spoofing */
+	br = p->br;
+	if (p->flags & BR_LEARNING)
+		br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, false);
+
+	if (!is_broadcast_ether_addr(dest) && is_multicast_ether_addr(dest) &&
+	    br_multicast_rcv(br, p, skb, vid))
+		goto drop;
+
+	if (p->state == BR_STATE_LEARNING)
+		goto drop;
+
+	BR_INPUT_SKB_CB(skb)->brdev = br->dev;
+
+	/* The packet skb2 goes to the local host (NULL to skip). */
+	skb2 = NULL;
+
+	if (br->dev->flags & IFF_PROMISC)
+		skb2 = skb;
+
+	dst = NULL;
+
+	if (IS_ENABLED(CONFIG_INET) && skb->protocol == htons(ETH_P_ARP))
+		br_do_proxy_arp(skb, br, vid, p);
+
+	if (is_broadcast_ether_addr(dest)) {
+		skb2 = skb;
+		unicast = false;
+	} else if (is_multicast_ether_addr(dest)) {
+		mdst = br_mdb_get(br, skb, vid);
+		if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
+		    br_multicast_querier_exists(br, eth_hdr(skb))) {
+			if ((mdst && mdst->mglist) ||
+			    br_multicast_is_router(br))
+				skb2 = skb;
+			br_multicast_forward(mdst, skb, skb2);
+			skb = NULL;
+			if (!skb2)
+				goto out;
+		} else
+			skb2 = skb;
+
+		unicast = false;
+		br->dev->stats.multicast++;
+	} else if ((dst = __br_fdb_get(br, dest, vid)) &&
+			dst->is_local) {
+		skb2 = skb;
+		/* Do not forward the packet since it's local. */
+		skb = NULL;
+	}
+
+	if (skb) {
+		if (dst) {
+			dst->used = jiffies;
+			br_forward(dst->dst, skb, skb2);
+		} else
+			br_flood_forward(br, skb, skb2, unicast);
+	}
+
+	if (skb2)
+		return br_pass_frame_up(skb2);
+
+out:
+	return 0;
+drop:
+	kfree_skb(skb);
+	goto out;
+}
+EXPORT_SYMBOL_GPL(br_handle_frame_finish);
+
+/* note: already called with rcu_read_lock */
+static int br_handle_local_finish(struct sock *sk, struct sk_buff *skb)
+{
+	struct net_bridge_port *p = br_port_get_rcu(skb->dev);
+	u16 vid = 0;
+
+	/* check if vlan is allowed, to avoid spoofing */
+	if (p->flags & BR_LEARNING && br_should_learn(p, skb, &vid))
+		br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid, false);
+	return 0;	 /* process further */
+}
+
+/*
+ * Return NULL if skb is handled
+ * note: already called with rcu_read_lock
+ */
+rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
+{
+	struct net_bridge_port *p;
+	struct sk_buff *skb = *pskb;
+	const unsigned char *dest = eth_hdr(skb)->h_dest;
+	br_should_route_hook_t *rhook;
+
+	if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
+		return RX_HANDLER_PASS;
+
+	if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
+		goto drop;
+
+	skb = skb_share_check(skb, GFP_ATOMIC);
+	if (!skb)
+		return RX_HANDLER_CONSUMED;
+
+	p = br_port_get_rcu(skb->dev);
+
+	if (unlikely(is_link_local_ether_addr(dest))) {
+		u16 fwd_mask = p->br->group_fwd_mask_required;
+
+		/*
+		 * See IEEE 802.1D Table 7-10 Reserved addresses
+		 *
+		 * Assignment		 		Value
+		 * Bridge Group Address		01-80-C2-00-00-00
+		 * (MAC Control) 802.3		01-80-C2-00-00-01
+		 * (Link Aggregation) 802.3	01-80-C2-00-00-02
+		 * 802.1X PAE address		01-80-C2-00-00-03
+		 *
+		 * 802.1AB LLDP 		01-80-C2-00-00-0E
+		 *
+		 * Others reserved for future standardization
+		 */
+		switch (dest[5]) {
+		case 0x00:	/* Bridge Group Address */
+			/* If STP is turned off,
+			   then must forward to keep loop detection */
+			if (p->br->stp_enabled == BR_NO_STP ||
+			    fwd_mask & (1u << dest[5]))
+				goto forward;
+			break;
+
+		case 0x01:	/* IEEE MAC (Pause) */
+			goto drop;
+
+		default:
+			/* Allow selective forwarding for most other protocols */
+			fwd_mask |= p->br->group_fwd_mask;
+			if (fwd_mask & (1u << dest[5]))
+				goto forward;
+		}
+
+		/* Deliver packet to local host only */
+		if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, NULL, skb,
+			    skb->dev, NULL, br_handle_local_finish)) {
+			return RX_HANDLER_CONSUMED; /* consumed by filter */
+		} else {
+			*pskb = skb;
+			return RX_HANDLER_PASS;	/* continue processing */
+		}
+	}
+
+forward:
+	switch (p->state) {
+	case BR_STATE_FORWARDING:
+		rhook = rcu_dereference(br_should_route_hook);
+		if (rhook) {
+			if ((*rhook)(skb)) {
+				*pskb = skb;
+				return RX_HANDLER_PASS;
+			}
+			dest = eth_hdr(skb)->h_dest;
+		}
+		/* fall through */
+	case BR_STATE_LEARNING:
+		if (ether_addr_equal(p->br->dev->dev_addr, dest))
+			skb->pkt_type = PACKET_HOST;
+
+		NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, NULL, skb,
+			skb->dev, NULL,
+			br_handle_frame_finish);
+		break;
+	default:
+drop:
+		kfree_skb(skb);
+	}
+	return RX_HANDLER_CONSUMED;
+}