Allow the user to switch from the current per-VLAN STP mode to an MST mode.
Up to this point, per-VLAN STP states where always isolated from each other. This is in contrast to the MSTP standard (802.1Q-2018, Clause 13.5), where VLANs are grouped into MST instances (MSTIs), and the state is managed on a per-MSTI level, rather that at the per-VLAN level. Perhaps due to the prevalence of the standard, many switching ASICs are built after the same model. Therefore, add a corresponding MST mode to the bridge, which we can later add offloading support for in a straight-forward way. For now, all VLANs are fixed to MSTI 0, also called the Common Spanning Tree (CST). That is, all VLANs will follow the port-global state. Upcoming changes will make this actually useful by allowing VLANs to be mapped to arbitrary MSTIs and allow individual MSTI states to be changed. Signed-off-by: Tobias Waldekranz <[email protected]> --- include/uapi/linux/if_bridge.h | 1 + net/bridge/Makefile | 2 +- net/bridge/br.c | 5 ++ net/bridge/br_input.c | 17 ++++++- net/bridge/br_mst.c | 84 ++++++++++++++++++++++++++++++++++ net/bridge/br_private.h | 27 +++++++++++ net/bridge/br_stp.c | 3 ++ net/bridge/br_vlan.c | 20 +++++++- net/bridge/br_vlan_options.c | 5 ++ 9 files changed, 160 insertions(+), 4 deletions(-) create mode 100644 net/bridge/br_mst.c diff --git a/include/uapi/linux/if_bridge.h b/include/uapi/linux/if_bridge.h index 2711c3522010..30a242195ced 100644 --- a/include/uapi/linux/if_bridge.h +++ b/include/uapi/linux/if_bridge.h @@ -759,6 +759,7 @@ struct br_mcast_stats { enum br_boolopt_id { BR_BOOLOPT_NO_LL_LEARN, BR_BOOLOPT_MCAST_VLAN_SNOOPING, + BR_BOOLOPT_MST_ENABLE, BR_BOOLOPT_MAX }; diff --git a/net/bridge/Makefile b/net/bridge/Makefile index 7fb9a021873b..24bd1c0a9a5a 100644 --- a/net/bridge/Makefile +++ b/net/bridge/Makefile @@ -20,7 +20,7 @@ obj-$(CONFIG_BRIDGE_NETFILTER) += br_netfilter.o bridge-$(CONFIG_BRIDGE_IGMP_SNOOPING) += br_multicast.o br_mdb.o br_multicast_eht.o -bridge-$(CONFIG_BRIDGE_VLAN_FILTERING) += br_vlan.o br_vlan_tunnel.o br_vlan_options.o +bridge-$(CONFIG_BRIDGE_VLAN_FILTERING) += br_vlan.o br_vlan_tunnel.o br_vlan_options.o br_mst.o bridge-$(CONFIG_NET_SWITCHDEV) += br_switchdev.o diff --git a/net/bridge/br.c b/net/bridge/br.c index b1dea3febeea..96e91d69a9a8 100644 --- a/net/bridge/br.c +++ b/net/bridge/br.c @@ -265,6 +265,9 @@ int br_boolopt_toggle(struct net_bridge *br, enum br_boolopt_id opt, bool on, case BR_BOOLOPT_MCAST_VLAN_SNOOPING: err = br_multicast_toggle_vlan_snooping(br, on, extack); break; + case BR_BOOLOPT_MST_ENABLE: + err = br_mst_set_enabled(br, on, extack); + break; default: /* shouldn't be called with unsupported options */ WARN_ON(1); @@ -281,6 +284,8 @@ int br_boolopt_get(const struct net_bridge *br, enum br_boolopt_id opt) return br_opt_get(br, BROPT_NO_LL_LEARN); case BR_BOOLOPT_MCAST_VLAN_SNOOPING: return br_opt_get(br, BROPT_MCAST_VLAN_SNOOPING_ENABLED); + case BR_BOOLOPT_MST_ENABLE: + return br_opt_get(br, BROPT_MST_ENABLED); default: /* shouldn't be called with unsupported options */ WARN_ON(1); diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c index e0c13fcc50ed..196417859c4a 100644 --- a/net/bridge/br_input.c +++ b/net/bridge/br_input.c @@ -78,13 +78,22 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb u16 vid = 0; u8 state; - if (!p || p->state == BR_STATE_DISABLED) + 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; - state = p->state; if (!br_allowed_ingress(p->br, nbp_vlan_group_rcu(p), skb, &vid, &state, &vlan)) goto out; @@ -370,9 +379,13 @@ static rx_handler_result_t br_handle_frame(struct sk_buff **pskb) 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; diff --git a/net/bridge/br_mst.c b/net/bridge/br_mst.c new file mode 100644 index 000000000000..e1ec9d39c660 --- /dev/null +++ b/net/bridge/br_mst.c @@ -0,0 +1,84 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Bridge Multiple Spanning Tree Support + * + * Authors: + * Tobias Waldekranz <[email protected]> + */ + +#include <linux/kernel.h> + +#include "br_private.h" + +DEFINE_STATIC_KEY_FALSE(br_mst_used); + +static void br_mst_vlan_set_state(struct net_bridge_port *p, struct net_bridge_vlan *v, + u8 state) +{ + struct net_bridge_vlan_group *vg = nbp_vlan_group(p); + + if (v->state == state) + return; + + br_vlan_set_state(v, state); + + if (v->vid == vg->pvid) + br_vlan_set_pvid_state(vg, state); +} + +void br_mst_set_state(struct net_bridge_port *p, u16 msti, u8 state) +{ + struct net_bridge_vlan_group *vg; + struct net_bridge_vlan *v; + + vg = nbp_vlan_group(p); + if (!vg) + return; + + list_for_each_entry(v, &vg->vlan_list, vlist) { + if (v->brvlan->msti != msti) + continue; + + br_mst_vlan_set_state(p, v, state); + } +} + +void br_mst_vlan_init_state(struct net_bridge_vlan *v) +{ + /* VLANs always start out in MSTI 0 (CST) */ + v->msti = 0; + + if (br_vlan_is_master(v)) + v->state = BR_STATE_FORWARDING; + else + v->state = v->port->state; +} + +int br_mst_set_enabled(struct net_bridge *br, bool on, + struct netlink_ext_ack *extack) +{ + struct net_bridge_vlan_group *vg; + struct net_bridge_port *p; + + list_for_each_entry(p, &br->port_list, list) { + vg = nbp_vlan_group(p); + + if (!vg->num_vlans) + continue; + + NL_SET_ERR_MSG(extack, + "MST mode can't be changed while VLANs exist"); + return -EBUSY; + } + + if (br_opt_get(br, BROPT_MST_ENABLED) == on) + return 0; + + if (on) + static_branch_enable(&br_mst_used); + else + static_branch_disable(&br_mst_used); + + br_opt_toggle(br, BROPT_MST_ENABLED, on); + return 0; +} diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h index 48bc61ebc211..35b47f6b449a 100644 --- a/net/bridge/br_private.h +++ b/net/bridge/br_private.h @@ -178,6 +178,7 @@ enum { * @br_mcast_ctx: if MASTER flag set, this is the global vlan multicast context * @port_mcast_ctx: if MASTER flag unset, this is the per-port/vlan multicast * context + * @msti: if MASTER flag set, this holds the VLANs MST instance * @vlist: sorted list of VLAN entries * @rcu: used for entry destruction * @@ -210,6 +211,8 @@ struct net_bridge_vlan { struct net_bridge_mcast_port port_mcast_ctx; }; + u16 msti; + struct list_head vlist; struct rcu_head rcu; @@ -445,6 +448,7 @@ enum net_bridge_opts { BROPT_NO_LL_LEARN, BROPT_VLAN_BRIDGE_BINDING, BROPT_MCAST_VLAN_SNOOPING_ENABLED, + BROPT_MST_ENABLED, }; struct net_bridge { @@ -1765,6 +1769,29 @@ static inline bool br_vlan_state_allowed(u8 state, bool learn_allow) } #endif +/* br_mst.c */ +#ifdef CONFIG_BRIDGE_VLAN_FILTERING +DECLARE_STATIC_KEY_FALSE(br_mst_used); +static inline bool br_mst_is_enabled(struct net_bridge *br) +{ + return static_branch_unlikely(&br_mst_used) && + br_opt_get(br, BROPT_MST_ENABLED); +} + +void br_mst_set_state(struct net_bridge_port *p, u16 msti, u8 state); +void br_mst_vlan_init_state(struct net_bridge_vlan *v); +int br_mst_set_enabled(struct net_bridge *br, bool on, + struct netlink_ext_ack *extack); +#else +static inline bool br_mst_is_enabled(struct net_bridge *br) +{ + return false; +} + +static inline void br_mst_set_state(struct net_bridge_port *p, + u16 msti, u8 state) {} +#endif + struct nf_br_ops { int (*br_dev_xmit_hook)(struct sk_buff *skb); }; diff --git a/net/bridge/br_stp.c b/net/bridge/br_stp.c index 1d80f34a139c..82a97a021a57 100644 --- a/net/bridge/br_stp.c +++ b/net/bridge/br_stp.c @@ -43,6 +43,9 @@ void br_set_state(struct net_bridge_port *p, unsigned int state) return; p->state = state; + if (br_opt_get(p->br, BROPT_MST_ENABLED)) + br_mst_set_state(p, 0, state); + err = switchdev_port_attr_set(p->dev, &attr, NULL); if (err && err != -EOPNOTSUPP) br_warn(p->br, "error setting offload STP state on port %u(%s)\n", diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c index 7557e90b60e1..0f5e75ccac79 100644 --- a/net/bridge/br_vlan.c +++ b/net/bridge/br_vlan.c @@ -226,6 +226,24 @@ static void nbp_vlan_rcu_free(struct rcu_head *rcu) kfree(v); } +static void br_vlan_init_state(struct net_bridge_vlan *v) +{ + struct net_bridge *br; + + if (br_vlan_is_master(v)) + br = v->br; + else + br = v->port->br; + + if (br_opt_get(br, BROPT_MST_ENABLED)) { + br_mst_vlan_init_state(v); + return; + } + + v->state = BR_STATE_FORWARDING; + v->msti = 0; +} + /* This is the shared VLAN add function which works for both ports and bridge * devices. There are four possible calls to this function in terms of the * vlan entry type: @@ -322,7 +340,7 @@ static int __vlan_add(struct net_bridge_vlan *v, u16 flags, } /* set the state before publishing */ - v->state = BR_STATE_FORWARDING; + br_vlan_init_state(v); err = rhashtable_lookup_insert_fast(&vg->vlan_hash, &v->vnode, br_vlan_rht_params); diff --git a/net/bridge/br_vlan_options.c b/net/bridge/br_vlan_options.c index a6382973b3e7..09112b56e79c 100644 --- a/net/bridge/br_vlan_options.c +++ b/net/bridge/br_vlan_options.c @@ -99,6 +99,11 @@ static int br_vlan_modify_state(struct net_bridge_vlan_group *vg, return -EBUSY; } + if (br_opt_get(br, BROPT_MST_ENABLED)) { + NL_SET_ERR_MSG_MOD(extack, "Can't modify vlan state directly when MST is enabled"); + return -EBUSY; + } + if (v->state == state) return 0; -- 2.25.1
