| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| * Handle incoming frames |
| * Linux ethernet bridge |
| * |
| * Authors: |
| * Lennert Buytenhek <buytenh@gnu.org> |
| */ |
| |
| #include <linux/slab.h> |
| #include <linux/kernel.h> |
| #include <linux/netdevice.h> |
| #include <linux/etherdevice.h> |
| #include <linux/netfilter_bridge.h> |
| #ifdef CONFIG_NETFILTER_FAMILY_BRIDGE |
| #include <net/netfilter/nf_queue.h> |
| #endif |
| #include <linux/neighbour.h> |
| #include <net/arp.h> |
| #include <net/dsa.h> |
| #include <linux/export.h> |
| #include <linux/rculist.h> |
| #include "br_private.h" |
| #include "br_private_tunnel.h" |
| |
| static int |
| br_netif_receive_skb(struct net *net, struct sock *sk, struct sk_buff *skb) |
| { |
| br_drop_fake_rtable(skb); |
| return netif_receive_skb(skb); |
| } |
| |
| 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 net_bridge_vlan_group *vg; |
| |
| dev_sw_netstats_rx_add(brdev, skb->len); |
| |
| vg = br_vlan_group_rcu(br); |
| |
| /* Reset the offload_fwd_mark because there could be a stacked |
| * bridge above, and it should not think this bridge it doing |
| * that bridge's work forwarding out its ports. |
| */ |
| br_switchdev_frame_unmark(skb); |
| |
| /* Bridge is just like any other port. Make sure the |
| * packet is allowed except in promisc mode when someone |
| * may be running packet capture. |
| */ |
| if (!(brdev->flags & IFF_PROMISC) && |
| !br_allowed_egress(vg, skb)) { |
| kfree_skb(skb); |
| return NET_RX_DROP; |
| } |
| |
| indev = skb->dev; |
| skb->dev = brdev; |
| skb = br_handle_vlan(br, NULL, vg, skb); |
| if (!skb) |
| return NET_RX_DROP; |
| /* update the multicast stats if the packet is IGMP/MLD */ |
| br_multicast_count(br, NULL, skb, br_multicast_igmp_type(skb), |
| BR_MCAST_DIR_TX); |
| |
| return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, |
| dev_net(indev), NULL, skb, indev, NULL, |
| br_netif_receive_skb); |
| } |
| |
| /* note: already called with rcu_read_lock */ |
| int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb) |
| { |
| struct net_bridge_port *p = br_port_get_rcu(skb->dev); |
| enum br_pkt_type pkt_type = BR_PKT_UNICAST; |
| struct net_bridge_fdb_entry *dst = NULL; |
| struct net_bridge_mcast_port *pmctx; |
| struct net_bridge_mdb_entry *mdst; |
| bool local_rcv, mcast_hit = false; |
| struct net_bridge_mcast *brmctx; |
| struct net_bridge_vlan *vlan; |
| struct net_bridge *br; |
| u16 vid = 0; |
| u8 state; |
| |
| if (!p) |
| goto drop; |
| |
| br = p->br; |
| |
| if (br_mst_is_enabled(br)) { |
| state = BR_STATE_FORWARDING; |
| } else { |
| if (p->state == BR_STATE_DISABLED) |
| goto drop; |
| |
| state = p->state; |
| } |
| |
| brmctx = &p->br->multicast_ctx; |
| pmctx = &p->multicast_ctx; |
| if (!br_allowed_ingress(p->br, nbp_vlan_group_rcu(p), skb, &vid, |
| &state, &vlan)) |
| goto out; |
| |
| if (p->flags & BR_PORT_LOCKED) { |
| struct net_bridge_fdb_entry *fdb_src = |
| br_fdb_find_rcu(br, eth_hdr(skb)->h_source, vid); |
| |
| if (!fdb_src || READ_ONCE(fdb_src->dst) != p || |
| test_bit(BR_FDB_LOCAL, &fdb_src->flags)) |
| goto drop; |
| } |
| |
| nbp_switchdev_frame_mark(p, skb); |
| |
| /* insert into forwarding database after filtering to avoid spoofing */ |
| if (p->flags & BR_LEARNING) |
| br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, 0); |
| |
| local_rcv = !!(br->dev->flags & IFF_PROMISC); |
| if (is_multicast_ether_addr(eth_hdr(skb)->h_dest)) { |
| /* by definition the broadcast is also a multicast address */ |
| if (is_broadcast_ether_addr(eth_hdr(skb)->h_dest)) { |
| pkt_type = BR_PKT_BROADCAST; |
| local_rcv = true; |
| } else { |
| pkt_type = BR_PKT_MULTICAST; |
| if (br_multicast_rcv(&brmctx, &pmctx, vlan, skb, vid)) |
| goto drop; |
| } |
| } |
| |
| if (state == BR_STATE_LEARNING) |
| goto drop; |
| |
| BR_INPUT_SKB_CB(skb)->brdev = br->dev; |
| BR_INPUT_SKB_CB(skb)->src_port_isolated = !!(p->flags & BR_ISOLATED); |
| |
| if (IS_ENABLED(CONFIG_INET) && |
| (skb->protocol == htons(ETH_P_ARP) || |
| skb->protocol == htons(ETH_P_RARP))) { |
| br_do_proxy_suppress_arp(skb, br, vid, p); |
| } else if (IS_ENABLED(CONFIG_IPV6) && |
| skb->protocol == htons(ETH_P_IPV6) && |
| br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED) && |
| pskb_may_pull(skb, sizeof(struct ipv6hdr) + |
| sizeof(struct nd_msg)) && |
| ipv6_hdr(skb)->nexthdr == IPPROTO_ICMPV6) { |
| struct nd_msg *msg, _msg; |
| |
| msg = br_is_nd_neigh_msg(skb, &_msg); |
| if (msg) |
| br_do_suppress_nd(skb, br, vid, p, msg); |
| } |
| |
| switch (pkt_type) { |
| case BR_PKT_MULTICAST: |
| mdst = br_mdb_get(brmctx, skb, vid); |
| if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) && |
| br_multicast_querier_exists(brmctx, eth_hdr(skb), mdst)) { |
| if ((mdst && mdst->host_joined) || |
| br_multicast_is_router(brmctx, skb)) { |
| local_rcv = true; |
| DEV_STATS_INC(br->dev, multicast); |
| } |
| mcast_hit = true; |
| } else { |
| local_rcv = true; |
| DEV_STATS_INC(br->dev, multicast); |
| } |
| break; |
| case BR_PKT_UNICAST: |
| dst = br_fdb_find_rcu(br, eth_hdr(skb)->h_dest, vid); |
| break; |
| default: |
| break; |
| } |
| |
| if (dst) { |
| unsigned long now = jiffies; |
| |
| if (test_bit(BR_FDB_LOCAL, &dst->flags)) |
| return br_pass_frame_up(skb); |
| |
| if (now != dst->used) |
| dst->used = now; |
| br_forward(dst->dst, skb, local_rcv, false); |
| } else { |
| if (!mcast_hit) |
| br_flood(br, skb, pkt_type, local_rcv, false); |
| else |
| br_multicast_flood(mdst, skb, brmctx, local_rcv, false); |
| } |
| |
| if (local_rcv) |
| return br_pass_frame_up(skb); |
| |
| out: |
| return 0; |
| drop: |
| kfree_skb(skb); |
| goto out; |
| } |
| EXPORT_SYMBOL_GPL(br_handle_frame_finish); |
| |
| static void __br_handle_local_finish(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) && |
| nbp_state_should_learn(p) && |
| !br_opt_get(p->br, BROPT_NO_LL_LEARN) && |
| br_should_learn(p, skb, &vid)) |
| br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid, 0); |
| } |
| |
| /* note: already called with rcu_read_lock */ |
| static int br_handle_local_finish(struct net *net, struct sock *sk, struct sk_buff *skb) |
| { |
| __br_handle_local_finish(skb); |
| |
| /* return 1 to signal the okfn() was called so it's ok to use the skb */ |
| return 1; |
| } |
| |
| static int nf_hook_bridge_pre(struct sk_buff *skb, struct sk_buff **pskb) |
| { |
| #ifdef CONFIG_NETFILTER_FAMILY_BRIDGE |
| struct nf_hook_entries *e = NULL; |
| struct nf_hook_state state; |
| unsigned int verdict, i; |
| struct net *net; |
| int ret; |
| |
| net = dev_net(skb->dev); |
| #ifdef HAVE_JUMP_LABEL |
| if (!static_key_false(&nf_hooks_needed[NFPROTO_BRIDGE][NF_BR_PRE_ROUTING])) |
| goto frame_finish; |
| #endif |
| |
| e = rcu_dereference(net->nf.hooks_bridge[NF_BR_PRE_ROUTING]); |
| if (!e) |
| goto frame_finish; |
| |
| nf_hook_state_init(&state, NF_BR_PRE_ROUTING, |
| NFPROTO_BRIDGE, skb->dev, NULL, NULL, |
| net, br_handle_frame_finish); |
| |
| for (i = 0; i < e->num_hook_entries; i++) { |
| verdict = nf_hook_entry_hookfn(&e->hooks[i], skb, &state); |
| switch (verdict & NF_VERDICT_MASK) { |
| case NF_ACCEPT: |
| if (BR_INPUT_SKB_CB(skb)->br_netfilter_broute) { |
| *pskb = skb; |
| return RX_HANDLER_PASS; |
| } |
| break; |
| case NF_DROP: |
| kfree_skb(skb); |
| return RX_HANDLER_CONSUMED; |
| case NF_QUEUE: |
| ret = nf_queue(skb, &state, i, verdict); |
| if (ret == 1) |
| continue; |
| return RX_HANDLER_CONSUMED; |
| default: /* STOLEN */ |
| return RX_HANDLER_CONSUMED; |
| } |
| } |
| frame_finish: |
| net = dev_net(skb->dev); |
| br_handle_frame_finish(net, NULL, skb); |
| #else |
| br_handle_frame_finish(dev_net(skb->dev), NULL, skb); |
| #endif |
| return RX_HANDLER_CONSUMED; |
| } |
| |
| /* Return 0 if the frame was not processed otherwise 1 |
| * note: already called with rcu_read_lock |
| */ |
| static int br_process_frame_type(struct net_bridge_port *p, |
| struct sk_buff *skb) |
| { |
| struct br_frame_type *tmp; |
| |
| hlist_for_each_entry_rcu(tmp, &p->br->frame_type_list, list) |
| if (unlikely(tmp->type == skb->protocol)) |
| return tmp->frame_handler(p, skb); |
| |
| return 0; |
| } |
| |
| /* |
| * Return NULL if skb is handled |
| * note: already called with rcu_read_lock |
| */ |
| static 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; |
| |
| 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; |
| |
| memset(skb->cb, 0, sizeof(struct br_input_skb_cb)); |
| |
| p = br_port_get_rcu(skb->dev); |
| if (p->flags & BR_VLAN_TUNNEL) |
| br_handle_ingress_vlan_tunnel(skb, p, nbp_vlan_group_rcu(p)); |
| |
| 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 |
| */ |
| fwd_mask |= p->group_fwd_mask; |
| 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; |
| *pskb = skb; |
| __br_handle_local_finish(skb); |
| return RX_HANDLER_PASS; |
| |
| case 0x01: /* IEEE MAC (Pause) */ |
| goto drop; |
| |
| case 0x0E: /* 802.1AB LLDP */ |
| fwd_mask |= p->br->group_fwd_mask; |
| if (fwd_mask & (1u << dest[5])) |
| goto forward; |
| *pskb = skb; |
| __br_handle_local_finish(skb); |
| return RX_HANDLER_PASS; |
| |
| default: |
| /* Allow selective forwarding for most other protocols */ |
| fwd_mask |= p->br->group_fwd_mask; |
| if (fwd_mask & (1u << dest[5])) |
| goto forward; |
| } |
| |
| /* The else clause should be hit when nf_hook(): |
| * - returns < 0 (drop/error) |
| * - returns = 0 (stolen/nf_queue) |
| * Thus return 1 from the okfn() to signal the skb is ok to pass |
| */ |
| if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, |
| dev_net(skb->dev), NULL, skb, skb->dev, NULL, |
| br_handle_local_finish) == 1) { |
| return RX_HANDLER_PASS; |
| } else { |
| return RX_HANDLER_CONSUMED; |
| } |
| } |
| |
| if (unlikely(br_process_frame_type(p, skb))) |
| return RX_HANDLER_PASS; |
| |
| forward: |
| if (br_mst_is_enabled(p->br)) |
| goto defer_stp_filtering; |
| |
| switch (p->state) { |
| case BR_STATE_FORWARDING: |
| case BR_STATE_LEARNING: |
| defer_stp_filtering: |
| if (ether_addr_equal(p->br->dev->dev_addr, dest)) |
| skb->pkt_type = PACKET_HOST; |
| |
| return nf_hook_bridge_pre(skb, pskb); |
| default: |
| drop: |
| kfree_skb(skb); |
| } |
| return RX_HANDLER_CONSUMED; |
| } |
| |
| /* This function has no purpose other than to appease the br_port_get_rcu/rtnl |
| * helpers which identify bridged ports according to the rx_handler installed |
| * on them (so there _needs_ to be a bridge rx_handler even if we don't need it |
| * to do anything useful). This bridge won't support traffic to/from the stack, |
| * but only hardware bridging. So return RX_HANDLER_PASS so we don't steal |
| * frames from the ETH_P_XDSA packet_type handler. |
| */ |
| static rx_handler_result_t br_handle_frame_dummy(struct sk_buff **pskb) |
| { |
| return RX_HANDLER_PASS; |
| } |
| |
| rx_handler_func_t *br_get_rx_handler(const struct net_device *dev) |
| { |
| if (netdev_uses_dsa(dev)) |
| return br_handle_frame_dummy; |
| |
| return br_handle_frame; |
| } |
| |
| void br_add_frame(struct net_bridge *br, struct br_frame_type *ft) |
| { |
| hlist_add_head_rcu(&ft->list, &br->frame_type_list); |
| } |
| |
| void br_del_frame(struct net_bridge *br, struct br_frame_type *ft) |
| { |
| struct br_frame_type *tmp; |
| |
| hlist_for_each_entry(tmp, &br->frame_type_list, list) |
| if (ft == tmp) { |
| hlist_del_rcu(&ft->list); |
| return; |
| } |
| } |