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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#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 intbr_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, bool promisc){ 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);
BR_INPUT_SKB_CB(skb)->promisc = promisc;
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){ enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED; 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; bool promisc; u16 vid = 0; u8 state;
if (!p) goto drop;
br = p->br;
if (br_mst_is_enabled(p)) { state = BR_STATE_FORWARDING; } else { if (p->state == BR_STATE_DISABLED) { reason = SKB_DROP_REASON_BRIDGE_INGRESS_STP_STATE; 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 (test_bit(BR_PORT_LOCKED_BIT, &p->flags)) { struct net_bridge_fdb_entry *fdb_src = br_fdb_find_rcu(br, eth_hdr(skb)->h_source, vid);
if (!fdb_src) { /* FDB miss. Create locked FDB entry if MAB is enabled * and drop the packet. */ if (test_bit(BR_PORT_MAB_BIT, &p->flags)) br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, BIT(BR_FDB_LOCKED)); goto drop; } else if (READ_ONCE(fdb_src->dst) != p || test_bit(BR_FDB_LOCAL, &fdb_src->flags)) { /* FDB mismatch. Drop the packet without roaming. */ goto drop; } else if (test_bit(BR_FDB_LOCKED, &fdb_src->flags)) { /* FDB match, but entry is locked. Refresh it and drop * the packet. */ br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, BIT(BR_FDB_LOCKED)); goto drop; } }
nbp_switchdev_frame_mark(p, skb);
/* insert into forwarding database after filtering to avoid spoofing */ if (test_bit(BR_LEARNING_BIT, &p->flags)) br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, 0);
promisc = !!(br->dev->flags & IFF_PROMISC); local_rcv = 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) { reason = SKB_DROP_REASON_BRIDGE_INGRESS_STP_STATE; goto drop; }
BR_INPUT_SKB_CB(skb)->brdev = br->dev; BR_INPUT_SKB_CB(skb)->src_port_isolated = test_bit(BR_ISOLATED_BIT, &p->flags);
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 (ipv6_mod_enabled() && 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_entry_skb_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) || br->dev->flags & IFF_ALLMULTI) { 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); if (unlikely(!dst && vid && br_opt_get(br, BROPT_FDB_LOCAL_VLAN_0))) { dst = br_fdb_find_rcu(br, eth_hdr(skb)->h_dest, 0); if (dst && (!test_bit(BR_FDB_LOCAL, &dst->flags) || test_bit(BR_FDB_ADDED_BY_USER, &dst->flags))) dst = NULL; } break; default: break; }
if (dst) { unsigned long now = jiffies;
if (test_bit(BR_FDB_LOCAL, &dst->flags)) return br_pass_frame_up(skb, false);
if (now != READ_ONCE(dst->used)) WRITE_ONCE(dst->used, now); br_forward(READ_ONCE(dst->dst), skb, local_rcv, false); } else { if (!mcast_hit) br_flood(br, skb, pkt_type, local_rcv, false, vid); else br_multicast_flood(mdst, skb, brmctx, local_rcv, false); }
if (local_rcv) return br_pass_frame_up(skb, promisc);
out: return 0;drop: kfree_skb_reason(skb, reason); 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 (test_bit(BR_LEARNING_BIT, &p->flags) && 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 CONFIG_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){ enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED; 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)) { reason = SKB_DROP_REASON_MAC_INVALID_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)); br_tc_skb_miss_set(skb, false);
p = br_port_get_rcu(skb->dev); if (test_bit(BR_VLAN_TUNNEL_BIT, &p->flags)) 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) */ reason = SKB_DROP_REASON_MAC_IEEE_MAC_CONTROL; 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; }
BR_INPUT_SKB_CB(skb)->promisc = false;
/* 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)) 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: reason = SKB_DROP_REASON_BRIDGE_INGRESS_STP_STATE;drop: kfree_skb_reason(skb, reason); } 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; }}