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Date: Mon, 16 Jan 2012 15:05:43 +0100
From: Štefan Gula <steweg@...il.com>
To: Eric Dumazet <eric.dumazet@...il.com>
Cc: Alexey Kuznetsov <kuznet@....inr.ac.ru>,
"David S. Miller" <davem@...emloft.net>,
James Morris <jmorris@...ei.org>,
Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
Patrick McHardy <kaber@...sh.net>, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [patch v1, kernel version 3.2.1] net/ipv4/ip_gre: Ethernet
multipoint GRE over IP
Dňa 16. januára 2012 14:19, Eric Dumazet <eric.dumazet@...il.com> napísal/a:
> Le lundi 16 janvier 2012 à 13:13 +0100, Štefan Gula a écrit :
>> From: Stefan Gula <steweg@...il.com
>>
>> This patch is an extension for current Ethernet over GRE
>> implementation, which allows user to create virtual bridge (multipoint
>> VPN) and forward traffic based on Ethernet MAC address informations in
>> it. It simulates the Bridge bahaviour learing mechanism, but instead
>> of learning port ID from which given MAC address comes, it learns IP
>> address of peer which encapsulated given packet. Multicast, Broadcast
>> and unknown-multicast traffic is send over network as multicast
>> enacapsulated GRE packet, so one Ethernet multipoint GRE tunnel can be
>> represented as one single virtual switch on logical level and be also
>> represented as one multicast IPv4 address on network level.
>>
>> Signed-off-by: Stefan Gula <steweg@...il.com>
>>
>> ---
>>
>> Patch was tested for more than one year in real network infrastructure
>> consisting of 98 Linux based access-points
>>
>
> OK, but please always send new patches on top on net-next tree.
>
>> diff -uprN -X linux-3.2.1-orig/Documentation/dontdiff
>> linux-3.2.1-orig/Documentation/dontdiff
>> linux-3.2.1-my/Documentation/dontdiff
>> --- linux-3.2.1-orig/Documentation/dontdiff 2012-01-16 12:32:18.000000000 +0100
>> +++ linux-3.2.1-my/Documentation/dontdiff 2012-01-12 20:42:45.000000000 +0100
>> @@ -260,5 +260,3 @@ wakeup.lds
>> zImage*
>> zconf.hash.c
>> zoffset.h
>> -mkpiggy
>> -mdp
>
> Hmm, what is this ?
Sorry, this one is not related to my patch, I have follwed the
guideline and those 2 files always end-up in my diff file even I
didn't modify them, so I have added them into dontdiff file assuming
that that file will not pop-up in my diff file. Apparently wrong
assumption, so please ignore those lines
>
>> diff -uprN -X linux-3.2.1-orig/Documentation/dontdiff
>> linux-3.2.1-orig/include/net/ipip.h linux-3.2.1-my/include/net/ipip.h
>> --- linux-3.2.1-orig/include/net/ipip.h 2012-01-12 20:42:45.000000000 +0100
>> +++ linux-3.2.1-my/include/net/ipip.h 2012-01-16 11:17:01.000000000 +0100
>> @@ -27,6 +27,14 @@ struct ip_tunnel {
>> __u32 o_seqno; /* The last output seqno */
>> int hlen; /* Precalculated GRE header length */
>> int mlink;
>> +#ifdef CONFIG_NET_IPGRE_BRIDGE
>> +#define GRETAP_BR_HASH_BITS 8
>> +#define GRETAP_BR_HASH_SIZE (1 << GRETAP_BR_HASH_BITS)
>> + struct hlist_head hash[GRETAP_BR_HASH_SIZE];
>> + spinlock_t hash_lock;
>> + unsigned long ageing_time;
>> + struct timer_list gc_timer;
>> +#endif
>>
>> struct ip_tunnel_parm parms;
>>
>> diff -uprN -X linux-3.2.1-orig/Documentation/dontdiff
>> linux-3.2.1-orig/net/ipv4/Kconfig linux-3.2.1-my/net/ipv4/Kconfig
>> --- linux-3.2.1-orig/net/ipv4/Kconfig 2012-01-12 20:42:45.000000000 +0100
>> +++ linux-3.2.1-my/net/ipv4/Kconfig 2012-01-16 12:37:00.000000000 +0100
>> @@ -211,6 +211,15 @@ config NET_IPGRE_BROADCAST
>> Network), but can be distributed all over the Internet. If you want
>> to do that, say Y here and to "IP multicast routing" below.
>>
>> +config NET_IPGRE_BRIDGE
>> + bool "IP: Ethernet over multipoint GRE over IP"
>> + depends on IP_MULTICAST && NET_IPGRE && NET_IPGRE_BROADCAST
>> + help
>> + Allows you to use multipoint GRE VPN as virtual switch and interconnect
>> + several L2 endpoints over L3 routed infrastructure. It is useful for
>> + creating multipoint L2 VPNs which can be later used inside bridge
>> + interfaces If you want to use. GRE multipoint L2 VPN feature say Y.
>> +
>> config IP_MROUTE
>> bool "IP: multicast routing"
>> depends on IP_MULTICAST
>> diff -uprN -X linux-3.2.1-orig/Documentation/dontdiff
>> linux-3.2.1-orig/net/ipv4/ip_gre.c linux-3.2.1-my/net/ipv4/ip_gre.c
>> --- linux-3.2.1-orig/net/ipv4/ip_gre.c 2012-01-12 20:42:45.000000000 +0100
>> +++ linux-3.2.1-my/net/ipv4/ip_gre.c 2012-01-16 12:29:03.000000000 +0100
>> @@ -52,6 +52,11 @@
>> #include <net/ip6_route.h>
>> #endif
>>
>> +#ifdef CONFIG_NET_IPGRE_BRIDGE
>> +#include <linux/jhash.h>
>> +#include <asm/unaligned.h>
>> +#endif
>> +
>> /*
>> Problems & solutions
>> --------------------
>> @@ -134,6 +139,199 @@ struct ipgre_net {
>> struct net_device *fb_tunnel_dev;
>> };
>>
>> +#ifdef CONFIG_NET_IPGRE_BRIDGE
>> + /*
>> + * This part of code includes codes to enable L2 ethernet
>> + * switch virtualization over IP routed infrastructure with
>> + * utilization of multicast capable endpoint using Ethernet
>> + * over GRE
>> + *
>> + * Author: Stefan Gula
>> + * Signed-off-by: Stefan Gula <steweg@...il.com>
>> + */
>> +struct mac_addr {
>> + unsigned char addr[6];
>
> Not sure if you need a 'struct mac_addr' for this...
>
> unsigned char mac_addr[ETH_ALEN] ?
not sure either, but I used in that time when I developed the code. Do
I have to change that to make this patch to kernel?
>> +};
>> +
>> +struct ipgre_tap_bridge_entry {
>> + struct hlist_node hlist;
>> + u32 raddr;
>> + struct mac_addr addr;
>> + struct net_device *dev;
>> + struct rcu_head rcu;
>> + atomic_t use_count;
>> + unsigned long ageing_timer;
>
>
>> +};
>> +
>> +static struct kmem_cache *ipgre_tap_bridge_cache __read_mostly;
>> +static u32 ipgre_salt __read_mostly;
>> +
>> +static inline int ipgre_tap_bridge_hash(const unsigned char *mac)
>> +{
>> + u32 key = get_unaligned((u32 *)(mac + 2));
>> + return jhash_1word(key, ipgre_salt) & (GRETAP_BR_HASH_SIZE - 1);
>> +}
>> +
>> +static inline int ipgre_tap_bridge_has_expired(const struct ip_tunnel *tunnel,
>> + const struct ipgre_tap_bridge_entry *entry)
>> +{
>> + return time_before_eq(entry->ageing_timer + tunnel->ageing_time,
>> + jiffies);
>> +}
>> +
>> +static void ipgre_tap_bridge_rcu_free(struct rcu_head *head)
>> +{
>> + struct ipgre_tap_bridge_entry *entry
>> + = container_of(head, struct ipgre_tap_bridge_entry, rcu);
>> + kmem_cache_free(ipgre_tap_bridge_cache, entry);
>> +}
>> +
>> +void ipgre_tap_bridge_put(struct ipgre_tap_bridge_entry *entry)
>> +{
>> + if (atomic_dec_and_test(&entry->use_count))
>> + call_rcu(&entry->rcu, ipgre_tap_bridge_rcu_free);
>
> You can now use kfree_rcu() and get rid of ipgre_tap_bridge_rcu_free()
hmm... for that part of code was copy & pasted from linux bridge code
from version 2.6.26. Do I have to change that or is it optional?
>
>> +}
>> +
>> +static inline void ipgre_tap_bridge_delete(struct
>> ipgre_tap_bridge_entry *entry)
>> +{
>> + hlist_del_rcu(&entry->hlist);
>> + ipgre_tap_bridge_put(entry);
>> +}
>> +
>> +static struct ipgre_tap_bridge_entry *ipgre_tap_bridge_create(
>> + struct hlist_head *head,
>> + u32 source,
>> + const unsigned char *addr, struct net_device *dev)
>> +{
>> + struct ipgre_tap_bridge_entry *entry;
>> + entry = kmem_cache_alloc(ipgre_tap_bridge_cache, GFP_ATOMIC);
>> + if (entry) {
>> + memcpy(entry->addr.addr, addr, ETH_ALEN);
>> + atomic_set(&entry->use_count, 1);
>> + hlist_add_head_rcu(&entry->hlist, head);
>> + entry->raddr = source;
>> + entry->ageing_timer = jiffies;
>> + entry->dev = dev;
>> + }
>> + return entry;
>> +}
>> +
>> +struct ipgre_tap_bridge_entry *__ipgre_tap_bridge_get(struct ip_tunnel *tunnel,
>> + const unsigned char *addr)
>> +{
>> + struct hlist_node *h;
>> + struct ipgre_tap_bridge_entry *entry;
>> + hlist_for_each_entry_rcu(entry, h,
>> + &tunnel->hash[ipgre_tap_bridge_hash(addr)], hlist)
>> + {
>> + if (!compare_ether_addr(entry->addr.addr, addr)) {
>> + if (unlikely(ipgre_tap_bridge_has_expired(tunnel,
>> + entry)))
>> + break;
>> + return entry;
>> + }
>> + }
>> +
>> + return NULL;
>> +}
>> +
>> +struct ipgre_tap_bridge_entry *ipgre_tap_bridge_get(struct ip_tunnel *tunnel,
>> + const unsigned char *addr)
>> +{
>> + struct ipgre_tap_bridge_entry *entry;
>> + rcu_read_lock();
>> + entry = __ipgre_tap_bridge_get(tunnel, addr);
>> + if (entry && !atomic_inc_not_zero(&entry->use_count))
>> + entry = NULL;
>> + rcu_read_unlock();
>> + return entry;
>> +}
>> +
>
> Unfortunately you call ipgre_tap_bridge_get() from
> ipgre_tap_bridge_get_raddr() but you dont release the refcount on
> use_count. Leak in ipgre_tunnel_xmit()
>
>
>> +__be32 ipgre_tap_bridge_get_raddr(struct ip_tunnel *tunnel,
>> + const unsigned char *addr)
>> +{
>> + struct ipgre_tap_bridge_entry *entry;
>> + entry = ipgre_tap_bridge_get(tunnel, addr);
>
> So maybe you want __ipgre_tap_bridge_get(tunnel, addr); here ?
>
Hmmm.. I am sorry, I am maybe not that expert on C coding, as most of
the codes were copied from linux bridge code. Can you give me a hint
how should I change that?
>> + if (entry == NULL)
>> + return 0;
>> + else
>> + return entry->raddr;
>> +}
>> +
>> +
>> +static inline struct ipgre_tap_bridge_entry *ipgre_tap_bridge_find(
>> + struct hlist_head *head,
>> + const unsigned char *addr)
>> +{
>> + struct hlist_node *h;
>> + struct ipgre_tap_bridge_entry *entry;
>> + hlist_for_each_entry_rcu(entry, h, head, hlist) {
>> + if (!compare_ether_addr(entry->addr.addr, addr))
>
>
>
>> + return entry;
>> + }
>> + return NULL;
>> +}
>> +
>> +int ipgre_tap_bridge_init(void)
>> +{
>> + ipgre_tap_bridge_cache = kmem_cache_create("ipgre_tap_bridge_cache",
>> + sizeof(struct ipgre_tap_bridge_entry),
>> + 0,
>> + SLAB_HWCACHE_ALIGN, NULL);
>> + if (!ipgre_tap_bridge_cache)
>> + return -ENOMEM;
>> + get_random_bytes(&ipgre_salt, sizeof(ipgre_salt));
>> + return 0;
>> +}
>> +
>> +void ipgre_tap_bridge_fini(void)
>> +{
>> + kmem_cache_destroy(ipgre_tap_bridge_cache);
>> +}
>> +
>> +void ipgre_tap_bridge_cleanup(unsigned long _data)
>> +{
>> + struct ip_tunnel *tunnel = (struct ip_tunnel *)_data;
>> + unsigned long delay = tunnel->ageing_time;
>> + unsigned long next_timer = jiffies + tunnel->ageing_time;
>> + int i;
>> + spin_lock_bh(&tunnel->hash_lock);
>
> Since you are called from timer, no need to use _bh() variant.
again copied structure from linux bridge code
>
>
> spin_lock(&tunnel->hash_lock);
>
>> + for (i = 0; i < GRETAP_BR_HASH_SIZE; i++) {
>> + struct ipgre_tap_bridge_entry *entry;
>> + struct hlist_node *h, *n;
>> + hlist_for_each_entry_safe(entry, h, n,
>> + &tunnel->hash[i], hlist)
>> + {
>> + unsigned long this_timer;
>> + this_timer = entry->ageing_timer + delay;
>> + if (time_before_eq(this_timer, jiffies))
>> + ipgre_tap_bridge_delete(entry);
>> + else if (time_before(this_timer, next_timer))
>> + next_timer = this_timer;
>> + }
>> + }
>> + spin_unlock_bh(&tunnel->hash_lock);
>> + mod_timer(&tunnel->gc_timer, round_jiffies(next_timer + HZ/4));
>
> wow... why setup a 250 ms timer, if entries are valid 300 seconds ?
no idea, it was in original linux bridge code
>
>
>
>> +}
>> +
>> +void ipgre_tap_bridge_flush(struct ip_tunnel *tunnel)
>> +{
>> + int i;
>> + spin_lock_bh(&tunnel->hash_lock);
>> + for (i = 0; i < GRETAP_BR_HASH_SIZE; i++) {
>> + struct ipgre_tap_bridge_entry *entry;
>> + struct hlist_node *h, *n;
>> + hlist_for_each_entry_safe(entry, h, n,
>> + &tunnel->hash[i], hlist)
>> + {
>> + ipgre_tap_bridge_delete(entry);
>> + }
>> + }
>> + spin_unlock_bh(&tunnel->hash_lock);
>> +}
>> +
>> +#endif
>> +
>> /* Tunnel hash table */
>>
>> /*
>> @@ -563,6 +761,13 @@ static int ipgre_rcv(struct sk_buff *skb
>> int offset = 4;
>> __be16 gre_proto;
>>
>> +#ifdef CONFIG_NET_IPGRE_BRIDGE
>> + u32 orig_source;
>> + struct hlist_head *head;
>> + struct ipgre_tap_bridge_entry *entry;
>> + struct ethhdr *tethhdr;
>> +#endif
>> +
>> if (!pskb_may_pull(skb, 16))
>> goto drop_nolock;
>>
>> @@ -659,10 +864,38 @@ static int ipgre_rcv(struct sk_buff *skb
>> tunnel->dev->stats.rx_errors++;
>> goto drop;
>> }
>> -
>> +#ifdef CONFIG_NET_IPGRE_BRIDGE
>> + orig_source = iph->saddr;
>> +#endif
>> iph = ip_hdr(skb);
>> skb->protocol = eth_type_trans(skb, tunnel->dev);
>> skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
>> +#ifdef CONFIG_NET_IPGRE_BRIDGE
>> + if (ipv4_is_multicast(tunnel->parms.iph.daddr)) {
>> + tethhdr = eth_hdr(skb);
>
>> + if ((tethhdr->h_source[0]&1) == 0) {
>
> if (!is_multicast_ether_addr(tethhdr->h_source)) ?
>
fixed
>> + head = &tunnel->hash[
>> + ipgre_tap_bridge_hash(
>> + tethhdr->h_source)];
>> + entry = ipgre_tap_bridge_find(head,
>> + tethhdr->h_source);
>> + if (likely(entry)) {
>> + entry->raddr = orig_source;
>> + entry->ageing_timer = jiffies;
>> + } else {
>> + spin_lock(&tunnel->hash_lock);
>> + if (!ipgre_tap_bridge_find(head,
>> + tethhdr->h_source))
>> + ipgre_tap_bridge_create(
>> + head,
>> + orig_source,
>> + tethhdr->h_source,
>> + tunnel->dev);
>> + spin_unlock(&tunnel->hash_lock);
>> + }
>> + }
>> + }
>> +#endif
>> }
>>
>> tstats = this_cpu_ptr(tunnel->dev->tstats);
>> @@ -716,7 +949,17 @@ static netdev_tx_t ipgre_tunnel_xmit(str
>> tiph = &tunnel->parms.iph;
>> }
>>
>> +#ifdef CONFIG_NET_IPGRE_BRIDGE
>> + if ((dev->type == ARPHRD_ETHER) && ipv4_is_multicast(
>
> please format like this :
>
> if ((dev->type == ARPHRD_ETHER) &&
> ipv4_is_multicast(tunnel->parms.iph.daddr))
>
fixed
>> + tunnel->parms.iph.daddr))
>> + dst = ipgre_tap_bridge_get_raddr(tunnel,
>> + ((struct ethhdr *)skb->data)->h_dest);
>> + if (dst == 0)
>> + dst = tiph->daddr;
>> + if (dst == 0) {
>> +#else
>> if ((dst = tiph->daddr) == 0) {
>> +#endif
>> /* NBMA tunnel */
>>
>> if (skb_dst(skb) == NULL) {
>> @@ -1209,6 +1452,16 @@ static int ipgre_open(struct net_device
>> return -EADDRNOTAVAIL;
>> t->mlink = dev->ifindex;
>> ip_mc_inc_group(__in_dev_get_rtnl(dev), t->parms.iph.daddr);
>> +#ifdef CONFIG_NET_IPGRE_BRIDGE
>> + if (t->dev->type == ARPHRD_ETHER) {
>> + INIT_HLIST_HEAD(t->hash);
>> + spin_lock_init(&t->hash_lock);
>> + t->ageing_time = 300 * HZ;
>> + setup_timer(&t->gc_timer, ipgre_tap_bridge_cleanup,
>> + (unsigned long) t);
>> + mod_timer(&t->gc_timer, jiffies + t->ageing_time);
>
>
>> + }
>> +#endif
>> }
>> return 0;
>> }
>> @@ -1219,6 +1472,12 @@ static int ipgre_close(struct net_device
>>
>> if (ipv4_is_multicast(t->parms.iph.daddr) && t->mlink) {
>> struct in_device *in_dev;
>> +#ifdef CONFIG_NET_IPGRE_BRIDGE
>> + if (t->dev->type == ARPHRD_ETHER) {
>> + ipgre_tap_bridge_flush(t);
>> + del_timer_sync(&t->gc_timer);
>> + }
>> +#endif
>> in_dev = inetdev_by_index(dev_net(dev), t->mlink);
>> if (in_dev)
>> ip_mc_dec_group(in_dev, t->parms.iph.daddr);
>> @@ -1341,6 +1600,12 @@ static int __net_init ipgre_init_net(str
>> struct ipgre_net *ign = net_generic(net, ipgre_net_id);
>> int err;
>>
>> +#ifdef CONFIG_NET_IPGRE_BRIDGE
>> + err = ipgre_tap_bridge_init();
>> + if (err)
>> + goto err_out;
>> +#endif
>> +
>> ign->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "gre0",
>> ipgre_tunnel_setup);
>> if (!ign->fb_tunnel_dev) {
>> @@ -1362,6 +1627,10 @@ static int __net_init ipgre_init_net(str
>> err_reg_dev:
>> ipgre_dev_free(ign->fb_tunnel_dev);
>> err_alloc_dev:
>> +#ifdef CONFIG_NET_IPGRE_BRIDGE
>> + ipgre_tap_bridge_fini();
>> +err_out:
>> +#endif
>> return err;
>> }
>>
>> @@ -1375,6 +1644,9 @@ static void __net_exit ipgre_exit_net(st
>> ipgre_destroy_tunnels(ign, &list);
>> unregister_netdevice_many(&list);
>> rtnl_unlock();
>> +#ifdef CONFIG_NET_IPGRE_BRIDGE
>> + ipgre_tap_bridge_fini();
>> +#endif
>> }
>>
>> static struct pernet_operations ipgre_net_ops = {
>>
>
>
--
Stefan Gula
CCNP, CCIP
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