/* * Handle incoming frames * Linux ethernet bridge * * Authors: * Lennert Buytenhek * * 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 #include #include #include #include #include #include #include #include #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_netif_receive_skb(struct net *net, struct sock *sk, struct sk_buff *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; struct pcpu_sw_netstats *brstats = this_cpu_ptr(br->stats); u64_stats_update_begin(&brstats->syncp); brstats->rx_packets++; brstats->rx_bytes += skb->len; u64_stats_update_end(&brstats->syncp); vg = br_vlan_group_rcu(br); /* Bridge is just like any other port. Make sure the * packet is allowed except in promisc modue 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, 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); } 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 net *net, struct sock *sk, struct sk_buff *skb) { bool local_rcv = false, mcast_hit = false, unicast = true; struct net_bridge_port *p = br_port_get_rcu(skb->dev); const unsigned char *dest = eth_hdr(skb)->h_dest; struct net_bridge_fdb_entry *dst = NULL; struct net_bridge_mdb_entry *mdst; struct net_bridge *br; u16 vid = 0; if (!p || p->state == BR_STATE_DISABLED) goto drop; if (!br_allowed_ingress(p->br, nbp_vlan_group_rcu(p), skb, &vid)) goto out; nbp_switchdev_frame_mark(p, skb); /* 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; local_rcv = !!(br->dev->flags & IFF_PROMISC); 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)) { local_rcv = true; 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)) { local_rcv = true; br->dev->stats.multicast++; } mcast_hit = true; } else { local_rcv = true; br->dev->stats.multicast++; } unicast = false; } else if ((dst = __br_fdb_get(br, dest, vid)) && dst->is_local) { /* Do not forward the packet since it's local. */ return br_pass_frame_up(skb); } if (dst) { dst->used = jiffies; br_forward(dst->dst, skb, local_rcv, false); } else { if (!mcast_hit) br_flood(br, skb, unicast, local_rcv, false); else br_multicast_flood(mdst, skb, 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 && br_should_learn(p, skb, &vid)) br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid, false); } /* note: already called with rcu_read_lock */ static int br_handle_local_finish(struct net *net, struct sock *sk, struct sk_buff *skb) { struct net_bridge_port *p = br_port_get_rcu(skb->dev); __br_handle_local_finish(skb); BR_INPUT_SKB_CB(skb)->brdev = p->br->dev; br_pass_frame_up(skb); return 0; } /* * 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; *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; } /* Deliver packet to local host only */ NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, dev_net(skb->dev), NULL, skb, skb->dev, NULL, br_handle_local_finish); return RX_HANDLER_CONSUMED; } 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, dev_net(skb->dev), NULL, skb, skb->dev, NULL, br_handle_frame_finish); break; default: drop: kfree_skb(skb); } return RX_HANDLER_CONSUMED; }