diff options
Diffstat (limited to 'net/bridge/br_forward.c')
| -rw-r--r-- | net/bridge/br_forward.c | 349 |
1 files changed, 349 insertions, 0 deletions
diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c new file mode 100644 index 000000000..7431f89e8 --- /dev/null +++ b/net/bridge/br_forward.c @@ -0,0 +1,349 @@ +// 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; + BR_INPUT_SKB_CB(skb)->backup_nhid = READ_ONCE(to->backup_nhid); + 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, + u16 vid) +{ + struct net_bridge_port *prev = NULL; + struct net_bridge_port *p; + + br_tc_skb_miss_set(skb, pkt_type != BR_PKT_BROADCAST); + + 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 (BR_INPUT_SKB_CB(skb)->proxyarp_replied && + ((p->flags & BR_PROXYARP_WIFI) || + br_is_neigh_suppress_enabled(p, vid))) + 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; + br_tc_skb_miss_set(skb, true); + } + + 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 |