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gre: Add Transparent Ethernet Bridging
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This patch adds support for Ethernet over GRE encapsulation.
This is exposed to user-space with a new link type of "gretap"
instead of "gre".  It will create an ARPHRD_ETHER device in
lieu of the usual ARPHRD_IPGRE.

Note that to preserver backwards compatibility all Transparent
Ethernet Bridging packets are passed to an ARPHRD_IPGRE tunnel
if its key matches and there is no ARPHRD_ETHER device whose
key matches more closely.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Herbert Xu authored and David S. Miller committed Oct 9, 2008
1 parent c19e654 commit e1a8000
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Showing 2 changed files with 175 additions and 32 deletions.
1 change: 1 addition & 0 deletions include/linux/if_ether.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -56,6 +56,7 @@
#define ETH_P_DIAG 0x6005 /* DEC Diagnostics */
#define ETH_P_CUST 0x6006 /* DEC Customer use */
#define ETH_P_SCA 0x6007 /* DEC Systems Comms Arch */
#define ETH_P_TEB 0x6558 /* Trans Ether Bridging */
#define ETH_P_RARP 0x8035 /* Reverse Addr Res packet */
#define ETH_P_ATALK 0x809B /* Appletalk DDP */
#define ETH_P_AARP 0x80F3 /* Appletalk AARP */
Expand Down
206 changes: 174 additions & 32 deletions net/ipv4/ip_gre.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@
#include <linux/inetdevice.h>
#include <linux/igmp.h>
#include <linux/netfilter_ipv4.h>
#include <linux/etherdevice.h>
#include <linux/if_ether.h>

#include <net/sock.h>
Expand Down Expand Up @@ -166,38 +167,64 @@ static DEFINE_RWLOCK(ipgre_lock);
/* Given src, dst and key, find appropriate for input tunnel. */

static struct ip_tunnel * ipgre_tunnel_lookup(struct net *net,
__be32 remote, __be32 local, __be32 key)
__be32 remote, __be32 local,
__be32 key, __be16 gre_proto)
{
unsigned h0 = HASH(remote);
unsigned h1 = HASH(key);
struct ip_tunnel *t;
struct ip_tunnel *t2 = NULL;
struct ipgre_net *ign = net_generic(net, ipgre_net_id);
int dev_type = (gre_proto == htons(ETH_P_TEB)) ?
ARPHRD_ETHER : ARPHRD_IPGRE;

for (t = ign->tunnels_r_l[h0^h1]; t; t = t->next) {
if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr) {
if (t->parms.i_key == key && (t->dev->flags&IFF_UP))
return t;
if (t->parms.i_key == key && t->dev->flags & IFF_UP) {
if (t->dev->type == dev_type)
return t;
if (t->dev->type == ARPHRD_IPGRE && !t2)
t2 = t;
}
}
}

for (t = ign->tunnels_r[h0^h1]; t; t = t->next) {
if (remote == t->parms.iph.daddr) {
if (t->parms.i_key == key && (t->dev->flags&IFF_UP))
return t;
if (t->parms.i_key == key && t->dev->flags & IFF_UP) {
if (t->dev->type == dev_type)
return t;
if (t->dev->type == ARPHRD_IPGRE && !t2)
t2 = t;
}
}
}

for (t = ign->tunnels_l[h1]; t; t = t->next) {
if (local == t->parms.iph.saddr ||
(local == t->parms.iph.daddr &&
ipv4_is_multicast(local))) {
if (t->parms.i_key == key && (t->dev->flags&IFF_UP))
return t;
if (t->parms.i_key == key && t->dev->flags & IFF_UP) {
if (t->dev->type == dev_type)
return t;
if (t->dev->type == ARPHRD_IPGRE && !t2)
t2 = t;
}
}
}

for (t = ign->tunnels_wc[h1]; t; t = t->next) {
if (t->parms.i_key == key && (t->dev->flags&IFF_UP))
return t;
if (t->parms.i_key == key && t->dev->flags & IFF_UP) {
if (t->dev->type == dev_type)
return t;
if (t->dev->type == ARPHRD_IPGRE && !t2)
t2 = t;
}
}

if (t2)
return t2;

if (ign->fb_tunnel_dev->flags&IFF_UP)
return netdev_priv(ign->fb_tunnel_dev);
return NULL;
Expand Down Expand Up @@ -252,25 +279,37 @@ static void ipgre_tunnel_unlink(struct ipgre_net *ign, struct ip_tunnel *t)
}
}

static struct ip_tunnel * ipgre_tunnel_locate(struct net *net,
struct ip_tunnel_parm *parms, int create)
static struct ip_tunnel *ipgre_tunnel_find(struct net *net,
struct ip_tunnel_parm *parms,
int type)
{
__be32 remote = parms->iph.daddr;
__be32 local = parms->iph.saddr;
__be32 key = parms->i_key;
struct ip_tunnel *t, **tp, *nt;
struct ip_tunnel *t, **tp;
struct ipgre_net *ign = net_generic(net, ipgre_net_id);

for (tp = __ipgre_bucket(ign, parms); (t = *tp) != NULL; tp = &t->next)
if (local == t->parms.iph.saddr &&
remote == t->parms.iph.daddr &&
key == t->parms.i_key &&
type == t->dev->type)
break;

return t;
}

static struct ip_tunnel * ipgre_tunnel_locate(struct net *net,
struct ip_tunnel_parm *parms, int create)
{
struct ip_tunnel *t, *nt;
struct net_device *dev;
char name[IFNAMSIZ];
struct ipgre_net *ign = net_generic(net, ipgre_net_id);

for (tp = __ipgre_bucket(ign, parms); (t = *tp) != NULL; tp = &t->next) {
if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr) {
if (key == t->parms.i_key)
return t;
}
}
if (!create)
return NULL;
t = ipgre_tunnel_find(net, parms, ARPHRD_IPGRE);
if (t || !create)
return t;

if (parms->name[0])
strlcpy(name, parms->name, IFNAMSIZ);
Expand Down Expand Up @@ -385,8 +424,9 @@ static void ipgre_err(struct sk_buff *skb, u32 info)

read_lock(&ipgre_lock);
t = ipgre_tunnel_lookup(dev_net(skb->dev), iph->daddr, iph->saddr,
(flags&GRE_KEY) ?
*(((__be32*)p) + (grehlen>>2) - 1) : 0);
flags & GRE_KEY ?
*(((__be32 *)p) + (grehlen / 4) - 1) : 0,
p[1]);
if (t == NULL || t->parms.iph.daddr == 0 ||
ipv4_is_multicast(t->parms.iph.daddr))
goto out;
Expand Down Expand Up @@ -436,6 +476,7 @@ static int ipgre_rcv(struct sk_buff *skb)
u32 seqno = 0;
struct ip_tunnel *tunnel;
int offset = 4;
__be16 gre_proto;

if (!pskb_may_pull(skb, 16))
goto drop_nolock;
Expand Down Expand Up @@ -475,28 +516,29 @@ static int ipgre_rcv(struct sk_buff *skb)
}
}

gre_proto = *(__be16 *)(h + 2);

read_lock(&ipgre_lock);
if ((tunnel = ipgre_tunnel_lookup(dev_net(skb->dev),
iph->saddr, iph->daddr, key)) != NULL) {
iph->saddr, iph->daddr, key,
gre_proto))) {
struct net_device_stats *stats = &tunnel->dev->stats;

secpath_reset(skb);

skb->protocol = *(__be16*)(h + 2);
skb->protocol = gre_proto;
/* WCCP version 1 and 2 protocol decoding.
* - Change protocol to IP
* - When dealing with WCCPv2, Skip extra 4 bytes in GRE header
*/
if (flags == 0 &&
skb->protocol == htons(ETH_P_WCCP)) {
if (flags == 0 && gre_proto == htons(ETH_P_WCCP)) {
skb->protocol = htons(ETH_P_IP);
if ((*(h + offset) & 0xF0) != 0x40)
offset += 4;
}

skb->mac_header = skb->network_header;
__pskb_pull(skb, offset);
skb_reset_network_header(skb);
skb_postpull_rcsum(skb, skb_transport_header(skb), offset);
skb->pkt_type = PACKET_HOST;
#ifdef CONFIG_NET_IPGRE_BROADCAST
Expand Down Expand Up @@ -524,13 +566,30 @@ static int ipgre_rcv(struct sk_buff *skb)
}
tunnel->i_seqno = seqno + 1;
}

/* Warning: All skb pointers will be invalidated! */
if (tunnel->dev->type == ARPHRD_ETHER) {
if (!pskb_may_pull(skb, ETH_HLEN)) {
stats->rx_length_errors++;
stats->rx_errors++;
goto drop;
}

iph = ip_hdr(skb);
skb->protocol = eth_type_trans(skb, tunnel->dev);
skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
}

stats->rx_packets++;
stats->rx_bytes += skb->len;
skb->dev = tunnel->dev;
dst_release(skb->dst);
skb->dst = NULL;
nf_reset(skb);

skb_reset_network_header(skb);
ipgre_ecn_decapsulate(iph, skb);

netif_rx(skb);
read_unlock(&ipgre_lock);
return(0);
Expand Down Expand Up @@ -565,7 +624,10 @@ static int ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
goto tx_error;
}

if (dev->header_ops) {
if (dev->type == ARPHRD_ETHER)
IPCB(skb)->flags = 0;

if (dev->header_ops && dev->type == ARPHRD_IPGRE) {
gre_hlen = 0;
tiph = (struct iphdr*)skb->data;
} else {
Expand Down Expand Up @@ -741,8 +803,9 @@ static int ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
iph->ttl = dst_metric(&rt->u.dst, RTAX_HOPLIMIT);
}

((__be16*)(iph+1))[0] = tunnel->parms.o_flags;
((__be16*)(iph+1))[1] = skb->protocol;
((__be16 *)(iph + 1))[0] = tunnel->parms.o_flags;
((__be16 *)(iph + 1))[1] = (dev->type == ARPHRD_ETHER) ?
htons(ETH_P_TEB) : skb->protocol;

if (tunnel->parms.o_flags&(GRE_KEY|GRE_CSUM|GRE_SEQ)) {
__be32 *ptr = (__be32*)(((u8*)iph) + tunnel->hlen - 4);
Expand Down Expand Up @@ -804,7 +867,9 @@ static int ipgre_tunnel_bind_dev(struct net_device *dev)
tdev = rt->u.dst.dev;
ip_rt_put(rt);
}
dev->flags |= IFF_POINTOPOINT;

if (dev->type != ARPHRD_ETHER)
dev->flags |= IFF_POINTOPOINT;
}

if (!tdev && tunnel->parms.link)
Expand Down Expand Up @@ -1250,6 +1315,30 @@ static int ipgre_tunnel_validate(struct nlattr *tb[], struct nlattr *data[])
return 0;
}

static int ipgre_tap_validate(struct nlattr *tb[], struct nlattr *data[])
{
__be32 daddr;

if (tb[IFLA_ADDRESS]) {
if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
return -EINVAL;
if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
return -EADDRNOTAVAIL;
}

if (!data)
goto out;

if (data[IFLA_GRE_REMOTE]) {
memcpy(&daddr, nla_data(data[IFLA_GRE_REMOTE]), 4);
if (!daddr)
return -EINVAL;
}

out:
return ipgre_tunnel_validate(tb, data);
}

static void ipgre_netlink_parms(struct nlattr *data[],
struct ip_tunnel_parm *parms)
{
Expand Down Expand Up @@ -1291,6 +1380,35 @@ static void ipgre_netlink_parms(struct nlattr *data[],
parms->iph.frag_off = htons(IP_DF);
}

static int ipgre_tap_init(struct net_device *dev)
{
struct ip_tunnel *tunnel;

tunnel = netdev_priv(dev);

tunnel->dev = dev;
strcpy(tunnel->parms.name, dev->name);

ipgre_tunnel_bind_dev(dev);

return 0;
}

static void ipgre_tap_setup(struct net_device *dev)
{

ether_setup(dev);

dev->init = ipgre_tap_init;
dev->uninit = ipgre_tunnel_uninit;
dev->destructor = free_netdev;
dev->hard_start_xmit = ipgre_tunnel_xmit;
dev->change_mtu = ipgre_tunnel_change_mtu;

dev->iflink = 0;
dev->features |= NETIF_F_NETNS_LOCAL;
}

static int ipgre_newlink(struct net_device *dev, struct nlattr *tb[],
struct nlattr *data[])
{
Expand All @@ -1303,9 +1421,12 @@ static int ipgre_newlink(struct net_device *dev, struct nlattr *tb[],
nt = netdev_priv(dev);
ipgre_netlink_parms(data, &nt->parms);

if (ipgre_tunnel_locate(net, &nt->parms, 0))
if (ipgre_tunnel_find(net, &nt->parms, dev->type))
return -EEXIST;

if (dev->type == ARPHRD_ETHER && !tb[IFLA_ADDRESS])
random_ether_addr(dev->dev_addr);

mtu = ipgre_tunnel_bind_dev(dev);
if (!tb[IFLA_MTU])
dev->mtu = mtu;
Expand Down Expand Up @@ -1455,6 +1576,19 @@ static struct rtnl_link_ops ipgre_link_ops __read_mostly = {
.fill_info = ipgre_fill_info,
};

static struct rtnl_link_ops ipgre_tap_ops __read_mostly = {
.kind = "gretap",
.maxtype = IFLA_GRE_MAX,
.policy = ipgre_policy,
.priv_size = sizeof(struct ip_tunnel),
.setup = ipgre_tap_setup,
.validate = ipgre_tap_validate,
.newlink = ipgre_newlink,
.changelink = ipgre_changelink,
.get_size = ipgre_get_size,
.fill_info = ipgre_fill_info,
};

/*
* And now the modules code and kernel interface.
*/
Expand All @@ -1478,9 +1612,15 @@ static int __init ipgre_init(void)
if (err < 0)
goto rtnl_link_failed;

err = rtnl_link_register(&ipgre_tap_ops);
if (err < 0)
goto tap_ops_failed;

out:
return err;

tap_ops_failed:
rtnl_link_unregister(&ipgre_link_ops);
rtnl_link_failed:
unregister_pernet_gen_device(ipgre_net_id, &ipgre_net_ops);
gen_device_failed:
Expand All @@ -1490,6 +1630,7 @@ static int __init ipgre_init(void)

static void __exit ipgre_fini(void)
{
rtnl_link_unregister(&ipgre_tap_ops);
rtnl_link_unregister(&ipgre_link_ops);
unregister_pernet_gen_device(ipgre_net_id, &ipgre_net_ops);
if (inet_del_protocol(&ipgre_protocol, IPPROTO_GRE) < 0)
Expand All @@ -1500,3 +1641,4 @@ module_init(ipgre_init);
module_exit(ipgre_fini);
MODULE_LICENSE("GPL");
MODULE_ALIAS("rtnl-link-gre");
MODULE_ALIAS("rtnl-link-gretap");

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