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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /net/bridge/br_input.c | |
parent | Initial commit. (diff) | |
download | linux-upstream/5.10.209.tar.xz linux-upstream/5.10.209.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'net/bridge/br_input.c')
-rw-r--r-- | net/bridge/br_input.c | 389 |
1 files changed, 389 insertions, 0 deletions
diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c new file mode 100644 index 000000000..52dd0708f --- /dev/null +++ b/net/bridge/br_input.c @@ -0,0 +1,389 @@ +// 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; + 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); + + /* 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 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, 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_mdb_entry *mdst; + bool local_rcv, mcast_hit = false; + struct net_bridge *br; + u16 vid = 0; + u8 state; + + if (!p || p->state == BR_STATE_DISABLED) + goto drop; + + state = p->state; + if (!br_allowed_ingress(p->br, nbp_vlan_group_rcu(p), skb, &vid, + &state)) + 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, 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(br, p, 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(br, skb, vid); + if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) && + br_multicast_querier_exists(br, eth_hdr(skb))) { + if ((mdst && mdst->host_joined) || + br_multicast_is_router(br)) { + 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); + 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, 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 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) { + if (br_handle_ingress_vlan_tunnel(skb, p, + nbp_vlan_group_rcu(p))) + goto drop; + } + + 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_mrp_process(p, skb))) + return RX_HANDLER_PASS; + +forward: + switch (p->state) { + case BR_STATE_FORWARDING: + case BR_STATE_LEARNING: + 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; +} |