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-rw-r--r--net/bridge/br_forward.c343
1 files changed, 343 insertions, 0 deletions
diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
new file mode 100644
index 000000000..4e3394a7d
--- /dev/null
+++ b/net/bridge/br_forward.c
@@ -0,0 +1,343 @@
+// 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 &&
+ eth_type_vlan(skb->protocol)) {
+ int depth;
+
+ if (!vlan_get_protocol_and_depth(skb, skb->protocol, &depth))
+ goto drop;
+
+ skb_set_network_header(skb, depth);
+ }
+
+ br_switchdev_frame_set_offload_fwd_mark(skb);
+
+ 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_clear_tstamp(skb);
+ 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;
+
+ /* Mark the skb for forwarding offload early so that br_handle_vlan()
+ * can know whether to pop the VLAN header on egress or keep it.
+ */
+ nbp_switchdev_frame_mark_tx_fwd_offload(to, skb);
+
+ 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;
+
+ nbp_switchdev_frame_mark_tx_fwd_to_hwdom(p, skb);
+
+ 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,
+ struct net_bridge_mcast *brmctx,
+ bool local_rcv, bool local_orig)
+{
+ struct net_bridge_port *prev = NULL;
+ struct net_bridge_port_group *p;
+ bool allow_mode_include = true;
+ struct hlist_node *rp;
+
+ rp = br_multicast_get_first_rport_node(brmctx, skb);
+
+ if (mdst) {
+ p = rcu_dereference(mdst->ports);
+ if (br_multicast_should_handle_mode(brmctx, 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 = br_multicast_rport_from_node_skb(rp, skb);
+
+ 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