[Bridge] [PATCH 1/6] bridge: lwtunnel support in FDB
David Lamparter
equinox at diac24.net
Mon Aug 21 17:15:18 UTC 2017
This implements holding tunnel config in the form of metadata_dst
information in the bridge layer, though only for unicast right now.
Multicast is still left to design and implement.
While struct lwtunnel_state might seem the more appropriate structure to
use here, there are two problems with that:
- I haven't found a good way to stuff it onto a SKB
(there's dst_entry->lwtstate, but if we're adding a dst, we might as
well go with a metadata_dst)
- it also needs to propagate upwards on received packets, which is
already in place for tunnel metadata collection
[v2: fixed race in fdb update with atomic_xchg]
[v3: consistently use metadata_dst pointer]
[v4: patch renamed]
Signed-off-by: David Lamparter <equinox at diac24.net>
---
include/net/dst_metadata.h | 27 ++++++++++++++++++---------
net/bridge/br_device.c | 4 ++++
net/bridge/br_fdb.c | 46 ++++++++++++++++++++++++++++++++--------------
net/bridge/br_input.c | 6 ++++--
net/bridge/br_private.h | 5 ++++-
5 files changed, 62 insertions(+), 26 deletions(-)
diff --git a/include/net/dst_metadata.h b/include/net/dst_metadata.h
index a803129a4849..4bcc0f314853 100644
--- a/include/net/dst_metadata.h
+++ b/include/net/dst_metadata.h
@@ -24,7 +24,7 @@ struct metadata_dst {
} u;
};
-static inline struct metadata_dst *skb_metadata_dst(struct sk_buff *skb)
+static inline struct metadata_dst *skb_metadata_dst(const struct sk_buff *skb)
{
struct metadata_dst *md_dst = (struct metadata_dst *) skb_dst(skb);
@@ -34,6 +34,11 @@ static inline struct metadata_dst *skb_metadata_dst(struct sk_buff *skb)
return NULL;
}
+static inline struct metadata_dst *metadata_dst_clone(struct metadata_dst *md_dst)
+{
+ return (struct metadata_dst *)dst_clone(&md_dst->dst);
+}
+
static inline struct ip_tunnel_info *skb_tunnel_info(struct sk_buff *skb)
{
struct metadata_dst *md_dst = skb_metadata_dst(skb);
@@ -56,17 +61,12 @@ static inline bool skb_valid_dst(const struct sk_buff *skb)
return dst && !(dst->flags & DST_METADATA);
}
-static inline int skb_metadata_dst_cmp(const struct sk_buff *skb_a,
- const struct sk_buff *skb_b)
+static inline int metadata_dst_cmp(const struct metadata_dst *a,
+ const struct metadata_dst *b)
{
- const struct metadata_dst *a, *b;
-
- if (!(skb_a->_skb_refdst | skb_b->_skb_refdst))
+ if (!(a || b))
return 0;
- a = (const struct metadata_dst *) skb_dst(skb_a);
- b = (const struct metadata_dst *) skb_dst(skb_b);
-
if (!a != !b || a->type != b->type)
return 1;
@@ -83,6 +83,15 @@ static inline int skb_metadata_dst_cmp(const struct sk_buff *skb_a,
}
}
+static inline int skb_metadata_dst_cmp(const struct sk_buff *skb_a,
+ const struct sk_buff *skb_b)
+{
+ if (!(skb_a->_skb_refdst | skb_b->_skb_refdst))
+ return 0;
+ return metadata_dst_cmp(skb_metadata_dst(skb_a),
+ skb_metadata_dst(skb_b));
+}
+
void metadata_dst_free(struct metadata_dst *);
struct metadata_dst *metadata_dst_alloc(u8 optslen, enum metadata_type type,
gfp_t flags);
diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index 861ae2a165f4..f98bc2016ddd 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -53,6 +53,7 @@ netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
brstats->tx_bytes += skb->len;
u64_stats_update_end(&brstats->syncp);
+ skb_dst_drop(skb);
BR_INPUT_SKB_CB(skb)->brdev = dev;
skb_reset_mac_header(skb);
@@ -81,6 +82,9 @@ netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
else
br_flood(br, skb, BR_PKT_MULTICAST, false, true);
} else if ((dst = br_fdb_find_rcu(br, dest, vid)) != NULL) {
+ struct metadata_dst *md_dst = rcu_dereference(dst->md_dst);
+ if (md_dst)
+ skb_dst_set_noref(skb, &md_dst->dst);
br_forward(dst->dst, skb, false, true);
} else {
br_flood(br, skb, BR_PKT_UNICAST, false, true);
diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index a79b648aac88..6ac3b916c39b 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -25,11 +25,13 @@
#include <asm/unaligned.h>
#include <linux/if_vlan.h>
#include <net/switchdev.h>
+#include <net/dst_metadata.h>
#include "br_private.h"
static struct kmem_cache *br_fdb_cache __read_mostly;
static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
- const unsigned char *addr, u16 vid);
+ struct metadata_dst *md_dst, const unsigned char *addr,
+ u16 vid);
static void fdb_notify(struct net_bridge *br,
const struct net_bridge_fdb_entry *, int);
@@ -174,6 +176,8 @@ static void fdb_delete(struct net_bridge *br, struct net_bridge_fdb_entry *f)
if (f->is_static)
fdb_del_hw_addr(br, f->addr.addr);
+ dst_release(&(rcu_access_pointer(f->md_dst)->dst));
+
hlist_del_init_rcu(&f->hlist);
fdb_notify(br, f, RTM_DELNEIGH);
call_rcu(&f->rcu, fdb_rcu_free);
@@ -260,7 +264,7 @@ void br_fdb_changeaddr(struct net_bridge_port *p, const unsigned char *newaddr)
insert:
/* insert new address, may fail if invalid address or dup. */
- fdb_insert(br, p, newaddr, 0);
+ fdb_insert(br, p, NULL, newaddr, 0);
if (!vg || !vg->num_vlans)
goto done;
@@ -270,7 +274,7 @@ void br_fdb_changeaddr(struct net_bridge_port *p, const unsigned char *newaddr)
* from under us.
*/
list_for_each_entry(v, &vg->vlan_list, vlist)
- fdb_insert(br, p, newaddr, v->vid);
+ fdb_insert(br, p, NULL, newaddr, v->vid);
done:
spin_unlock_bh(&br->hash_lock);
@@ -289,10 +293,11 @@ void br_fdb_change_mac_address(struct net_bridge *br, const u8 *newaddr)
if (f && f->is_local && !f->dst && !f->added_by_user)
fdb_delete_local(br, NULL, f);
- fdb_insert(br, NULL, newaddr, 0);
+ fdb_insert(br, NULL, NULL, newaddr, 0);
vg = br_vlan_group(br);
if (!vg || !vg->num_vlans)
goto out;
+
/* Now remove and add entries for every VLAN configured on the
* bridge. This function runs under RTNL so the bitmap will not
* change from under us.
@@ -303,7 +308,7 @@ void br_fdb_change_mac_address(struct net_bridge *br, const u8 *newaddr)
f = br_fdb_find(br, br->dev->dev_addr, v->vid);
if (f && f->is_local && !f->dst && !f->added_by_user)
fdb_delete_local(br, NULL, f);
- fdb_insert(br, NULL, newaddr, v->vid);
+ fdb_insert(br, NULL, NULL, newaddr, v->vid);
}
out:
spin_unlock_bh(&br->hash_lock);
@@ -477,6 +482,7 @@ int br_fdb_fillbuf(struct net_bridge *br, void *buf,
static struct net_bridge_fdb_entry *fdb_create(struct hlist_head *head,
struct net_bridge_port *source,
+ struct metadata_dst *md_dst,
const unsigned char *addr,
__u16 vid,
unsigned char is_local,
@@ -488,6 +494,7 @@ static struct net_bridge_fdb_entry *fdb_create(struct hlist_head *head,
if (fdb) {
memcpy(fdb->addr.addr, addr, ETH_ALEN);
fdb->dst = source;
+ rcu_assign_pointer(fdb->md_dst, metadata_dst_clone(md_dst));
fdb->vlan_id = vid;
fdb->is_local = is_local;
fdb->is_static = is_static;
@@ -501,7 +508,8 @@ static struct net_bridge_fdb_entry *fdb_create(struct hlist_head *head,
}
static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
- const unsigned char *addr, u16 vid)
+ struct metadata_dst *md_dst, const unsigned char *addr,
+ u16 vid)
{
struct hlist_head *head = &br->hash[br_mac_hash(addr, vid)];
struct net_bridge_fdb_entry *fdb;
@@ -521,7 +529,7 @@ static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
fdb_delete(br, fdb);
}
- fdb = fdb_create(head, source, addr, vid, 1, 1);
+ fdb = fdb_create(head, source, md_dst, addr, vid, 1, 1);
if (!fdb)
return -ENOMEM;
@@ -537,13 +545,14 @@ int br_fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
int ret;
spin_lock_bh(&br->hash_lock);
- ret = fdb_insert(br, source, addr, vid);
+ ret = fdb_insert(br, source, NULL, addr, vid);
spin_unlock_bh(&br->hash_lock);
return ret;
}
void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
- const unsigned char *addr, u16 vid, bool added_by_user)
+ struct metadata_dst *md_dst, const unsigned char *addr,
+ u16 vid, bool added_by_user)
{
struct hlist_head *head = &br->hash[br_mac_hash(addr, vid)];
struct net_bridge_fdb_entry *fdb;
@@ -567,10 +576,19 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
source->dev->name, addr, vid);
} else {
unsigned long now = jiffies;
+ struct metadata_dst *md_ref;
+
+ md_ref = rcu_access_pointer(fdb->md_dst);
/* fastpath: update of existing entry */
- if (unlikely(source != fdb->dst)) {
+ if (unlikely(source != fdb->dst ||
+ metadata_dst_cmp(md_dst, md_ref))) {
fdb->dst = source;
+
+ md_ref = xchg(&fdb->md_dst,
+ metadata_dst_clone(md_dst));
+ dst_release(&md_ref->dst);
+
fdb_modified = true;
/* Take over HW learned entry */
if (unlikely(fdb->added_by_external_learn))
@@ -586,7 +604,7 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
} else {
spin_lock(&br->hash_lock);
if (likely(!fdb_find_rcu(head, addr, vid))) {
- fdb = fdb_create(head, source, addr, vid, 0, 0);
+ fdb = fdb_create(head, source, md_dst, addr, vid, 0, 0);
if (fdb) {
if (unlikely(added_by_user))
fdb->added_by_user = 1;
@@ -781,7 +799,7 @@ static int fdb_add_entry(struct net_bridge *br, struct net_bridge_port *source,
if (!(flags & NLM_F_CREATE))
return -ENOENT;
- fdb = fdb_create(head, source, addr, vid, 0, 0);
+ fdb = fdb_create(head, source, NULL, addr, vid, 0, 0);
if (!fdb)
return -ENOMEM;
@@ -844,7 +862,7 @@ static int __br_fdb_add(struct ndmsg *ndm, struct net_bridge *br,
}
local_bh_disable();
rcu_read_lock();
- br_fdb_update(br, p, addr, vid, true);
+ br_fdb_update(br, p, NULL, addr, vid, true);
rcu_read_unlock();
local_bh_enable();
} else if (ndm->ndm_flags & NTF_EXT_LEARNED) {
@@ -1071,7 +1089,7 @@ int br_fdb_external_learn_add(struct net_bridge *br, struct net_bridge_port *p,
head = &br->hash[br_mac_hash(addr, vid)];
fdb = br_fdb_find(br, addr, vid);
if (!fdb) {
- fdb = fdb_create(head, p, addr, vid, 0, 0);
+ fdb = fdb_create(head, p, NULL, addr, vid, 0, 0);
if (!fdb) {
err = -ENOMEM;
goto err_unlock;
diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index 7637f58c1226..3fd0fab49de2 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -150,7 +150,8 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *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);
+ br_fdb_update(br, p, skb_metadata_dst(skb),
+ eth_hdr(skb)->h_source, vid, false);
local_rcv = !!(br->dev->flags & IFF_PROMISC);
dest = eth_hdr(skb)->h_dest;
@@ -230,7 +231,8 @@ static void __br_handle_local_finish(struct sk_buff *skb)
/* 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);
+ br_fdb_update(p->br, p, skb_metadata_dst(skb),
+ eth_hdr(skb)->h_source, vid, false);
}
/* note: already called with rcu_read_lock */
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index fd9ee73e0a6d..66d33352681f 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -22,6 +22,7 @@
#include <linux/if_vlan.h>
#include <linux/rhashtable.h>
#include <linux/refcount.h>
+#include <net/dst_metadata.h>
#define BR_HASH_BITS 8
#define BR_HASH_SIZE (1 << BR_HASH_BITS)
@@ -164,6 +165,7 @@ struct net_bridge_vlan_group {
struct net_bridge_fdb_entry {
struct hlist_node hlist;
struct net_bridge_port *dst;
+ struct metadata_dst __rcu *md_dst;
mac_addr addr;
__u16 vlan_id;
@@ -524,7 +526,8 @@ int br_fdb_fillbuf(struct net_bridge *br, void *buf, unsigned long count,
int br_fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
const unsigned char *addr, u16 vid);
void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
- const unsigned char *addr, u16 vid, bool added_by_user);
+ struct metadata_dst *md_dst, const unsigned char *addr,
+ u16 vid, bool added_by_user);
int br_fdb_delete(struct ndmsg *ndm, struct nlattr *tb[],
struct net_device *dev, const unsigned char *addr, u16 vid);
--
2.13.0
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