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add DOVE extensions for VXLAN
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This patch provides extensions to VXLAN for supporting Distributed
Overlay Virtual Ethernet (DOVE) networks. The patch includes:

	+ a dove flag per VXLAN device to enable DOVE extensions
	+ ARP reduction, whereby a bridge-connected VXLAN tunnel endpoint
		answers ARP requests from the local bridge on behalf of
		remote DOVE clients
	+ route short-circuiting (aka L3 switching). Known destination IP
		addresses use the corresponding destination MAC address for
		switching rather than going to a (possibly remote) router first.
	+ netlink notification messages for forwarding table and L3 switching
		misses

Changes since v2
	- combined bools into "u32 flags"
	- replaced loop with !is_zero_ether_addr()

Signed-off-by: David L Stevens <dlstevens@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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David Stevens authored and David S. Miller committed Nov 20, 2012
1 parent ff33c0e commit e4f67ad
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Showing 2 changed files with 235 additions and 25 deletions.
256 changes: 231 additions & 25 deletions drivers/net/vxlan.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,8 @@
#include <linux/etherdevice.h>
#include <linux/if_ether.h>
#include <linux/hash.h>
#include <net/arp.h>
#include <net/ndisc.h>
#include <net/ip.h>
#include <net/icmp.h>
#include <net/udp.h>
Expand Down Expand Up @@ -110,7 +112,7 @@ struct vxlan_dev {
__u16 port_max;
__u8 tos; /* TOS override */
__u8 ttl;
bool learn;
u32 flags; /* VXLAN_F_* below */

unsigned long age_interval;
struct timer_list age_timer;
Expand All @@ -121,6 +123,12 @@ struct vxlan_dev {
struct hlist_head fdb_head[FDB_HASH_SIZE];
};

#define VXLAN_F_LEARN 0x01
#define VXLAN_F_PROXY 0x02
#define VXLAN_F_RSC 0x04
#define VXLAN_F_L2MISS 0x08
#define VXLAN_F_L3MISS 0x10

/* salt for hash table */
static u32 vxlan_salt __read_mostly;

Expand Down Expand Up @@ -154,23 +162,32 @@ static int vxlan_fdb_info(struct sk_buff *skb, struct vxlan_dev *vxlan,
struct nda_cacheinfo ci;
struct nlmsghdr *nlh;
struct ndmsg *ndm;
bool send_ip, send_eth;

nlh = nlmsg_put(skb, portid, seq, type, sizeof(*ndm), flags);
if (nlh == NULL)
return -EMSGSIZE;

ndm = nlmsg_data(nlh);
memset(ndm, 0, sizeof(*ndm));
ndm->ndm_family = AF_BRIDGE;

send_eth = send_ip = true;

if (type == RTM_GETNEIGH) {
ndm->ndm_family = AF_INET;
send_ip = fdb->remote_ip != 0;
send_eth = !is_zero_ether_addr(fdb->eth_addr);
} else
ndm->ndm_family = AF_BRIDGE;
ndm->ndm_state = fdb->state;
ndm->ndm_ifindex = vxlan->dev->ifindex;
ndm->ndm_flags = NTF_SELF;
ndm->ndm_type = NDA_DST;

if (nla_put(skb, NDA_LLADDR, ETH_ALEN, &fdb->eth_addr))
if (send_eth && nla_put(skb, NDA_LLADDR, ETH_ALEN, &fdb->eth_addr))
goto nla_put_failure;

if (nla_put_be32(skb, NDA_DST, fdb->remote_ip))
if (send_ip && nla_put_be32(skb, NDA_DST, fdb->remote_ip))
goto nla_put_failure;

ci.ndm_used = jiffies_to_clock_t(now - fdb->used);
Expand Down Expand Up @@ -222,6 +239,29 @@ static void vxlan_fdb_notify(struct vxlan_dev *vxlan,
rtnl_set_sk_err(net, RTNLGRP_NEIGH, err);
}

static void vxlan_ip_miss(struct net_device *dev, __be32 ipa)
{
struct vxlan_dev *vxlan = netdev_priv(dev);
struct vxlan_fdb f;

memset(&f, 0, sizeof f);
f.state = NUD_STALE;
f.remote_ip = ipa; /* goes to NDA_DST */

vxlan_fdb_notify(vxlan, &f, RTM_GETNEIGH);
}

static void vxlan_fdb_miss(struct vxlan_dev *vxlan, const u8 eth_addr[ETH_ALEN])
{
struct vxlan_fdb f;

memset(&f, 0, sizeof f);
f.state = NUD_STALE;
memcpy(f.eth_addr, eth_addr, ETH_ALEN);

vxlan_fdb_notify(vxlan, &f, RTM_GETNEIGH);
}

/* Hash Ethernet address */
static u32 eth_hash(const unsigned char *addr)
{
Expand Down Expand Up @@ -551,6 +591,8 @@ static int vxlan_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
goto drop;
}

skb_reset_mac_header(skb);

/* Re-examine inner Ethernet packet */
oip = ip_hdr(skb);
skb->protocol = eth_type_trans(skb, vxlan->dev);
Expand All @@ -560,7 +602,7 @@ static int vxlan_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
vxlan->dev->dev_addr) == 0)
goto drop;

if (vxlan->learn)
if (vxlan->flags & VXLAN_F_LEARN)
vxlan_snoop(skb->dev, oip->saddr, eth_hdr(skb)->h_source);

__skb_tunnel_rx(skb, vxlan->dev);
Expand Down Expand Up @@ -599,6 +641,117 @@ static int vxlan_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
return 0;
}

static int arp_reduce(struct net_device *dev, struct sk_buff *skb)
{
struct vxlan_dev *vxlan = netdev_priv(dev);
struct arphdr *parp;
u8 *arpptr, *sha;
__be32 sip, tip;
struct neighbour *n;

if (dev->flags & IFF_NOARP)
goto out;

if (!pskb_may_pull(skb, arp_hdr_len(dev))) {
dev->stats.tx_dropped++;
goto out;
}
parp = arp_hdr(skb);

if ((parp->ar_hrd != htons(ARPHRD_ETHER) &&
parp->ar_hrd != htons(ARPHRD_IEEE802)) ||
parp->ar_pro != htons(ETH_P_IP) ||
parp->ar_op != htons(ARPOP_REQUEST) ||
parp->ar_hln != dev->addr_len ||
parp->ar_pln != 4)
goto out;
arpptr = (u8 *)parp + sizeof(struct arphdr);
sha = arpptr;
arpptr += dev->addr_len; /* sha */
memcpy(&sip, arpptr, sizeof(sip));
arpptr += sizeof(sip);
arpptr += dev->addr_len; /* tha */
memcpy(&tip, arpptr, sizeof(tip));

if (ipv4_is_loopback(tip) ||
ipv4_is_multicast(tip))
goto out;

n = neigh_lookup(&arp_tbl, &tip, dev);

if (n) {
struct vxlan_dev *vxlan = netdev_priv(dev);
struct vxlan_fdb *f;
struct sk_buff *reply;

if (!(n->nud_state & NUD_CONNECTED)) {
neigh_release(n);
goto out;
}

f = vxlan_find_mac(vxlan, n->ha);
if (f && f->remote_ip == 0) {
/* bridge-local neighbor */
neigh_release(n);
goto out;
}

reply = arp_create(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, sha,
n->ha, sha);

neigh_release(n);

skb_reset_mac_header(reply);
__skb_pull(reply, skb_network_offset(reply));
reply->ip_summed = CHECKSUM_UNNECESSARY;
reply->pkt_type = PACKET_HOST;

if (netif_rx_ni(reply) == NET_RX_DROP)
dev->stats.rx_dropped++;
} else if (vxlan->flags & VXLAN_F_L3MISS)
vxlan_ip_miss(dev, tip);
out:
consume_skb(skb);
return NETDEV_TX_OK;
}

static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb)
{
struct vxlan_dev *vxlan = netdev_priv(dev);
struct neighbour *n;
struct iphdr *pip;

if (is_multicast_ether_addr(eth_hdr(skb)->h_dest))
return false;

n = NULL;
switch (ntohs(eth_hdr(skb)->h_proto)) {
case ETH_P_IP:
if (!pskb_may_pull(skb, sizeof(struct iphdr)))
return false;
pip = ip_hdr(skb);
n = neigh_lookup(&arp_tbl, &pip->daddr, dev);
break;
default:
return false;
}

if (n) {
bool diff;

diff = compare_ether_addr(eth_hdr(skb)->h_dest, n->ha) != 0;
if (diff) {
memcpy(eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
dev->addr_len);
memcpy(eth_hdr(skb)->h_dest, n->ha, dev->addr_len);
}
neigh_release(n);
return diff;
} else if (vxlan->flags & VXLAN_F_L3MISS)
vxlan_ip_miss(dev, pip->daddr);
return false;
}

/* Extract dsfield from inner protocol */
static inline u8 vxlan_get_dsfield(const struct iphdr *iph,
const struct sk_buff *skb)
Expand All @@ -621,22 +774,6 @@ static inline u8 vxlan_ecn_encap(u8 tos,
return INET_ECN_encapsulate(tos, inner);
}

static __be32 vxlan_find_dst(struct vxlan_dev *vxlan, struct sk_buff *skb)
{
const struct ethhdr *eth = (struct ethhdr *) skb->data;
const struct vxlan_fdb *f;

if (is_multicast_ether_addr(eth->h_dest))
return vxlan->gaddr;

f = vxlan_find_mac(vxlan, eth->h_dest);
if (f)
return f->remote_ip;
else
return vxlan->gaddr;

}

static void vxlan_sock_free(struct sk_buff *skb)
{
sock_put(skb->sk);
Expand Down Expand Up @@ -683,6 +820,7 @@ static netdev_tx_t vxlan_xmit(struct sk_buff *skb, struct net_device *dev)
struct vxlan_dev *vxlan = netdev_priv(dev);
struct rtable *rt;
const struct iphdr *old_iph;
struct ethhdr *eth;
struct iphdr *iph;
struct vxlanhdr *vxh;
struct udphdr *uh;
Expand All @@ -693,10 +831,50 @@ static netdev_tx_t vxlan_xmit(struct sk_buff *skb, struct net_device *dev)
__be16 df = 0;
__u8 tos, ttl;
int err;
bool did_rsc = false;
const struct vxlan_fdb *f;

skb_reset_mac_header(skb);
eth = eth_hdr(skb);

if ((vxlan->flags & VXLAN_F_PROXY) && ntohs(eth->h_proto) == ETH_P_ARP)
return arp_reduce(dev, skb);
else if ((vxlan->flags&VXLAN_F_RSC) && ntohs(eth->h_proto) == ETH_P_IP)
did_rsc = route_shortcircuit(dev, skb);

dst = vxlan_find_dst(vxlan, skb);
if (!dst)
f = vxlan_find_mac(vxlan, eth->h_dest);
if (f == NULL) {
did_rsc = false;
dst = vxlan->gaddr;
if (!dst && (vxlan->flags & VXLAN_F_L2MISS) &&
!is_multicast_ether_addr(eth->h_dest))
vxlan_fdb_miss(vxlan, eth->h_dest);
} else
dst = f->remote_ip;

if (!dst) {
if (did_rsc) {
__skb_pull(skb, skb_network_offset(skb));
skb->ip_summed = CHECKSUM_NONE;
skb->pkt_type = PACKET_HOST;

/* short-circuited back to local bridge */
if (netif_rx(skb) == NET_RX_SUCCESS) {
struct vxlan_stats *stats =
this_cpu_ptr(vxlan->stats);

u64_stats_update_begin(&stats->syncp);
stats->tx_packets++;
stats->tx_bytes += pkt_len;
u64_stats_update_end(&stats->syncp);
} else {
dev->stats.tx_errors++;
dev->stats.tx_aborted_errors++;
}
return NETDEV_TX_OK;
}
goto drop;
}

/* Need space for new headers (invalidates iph ptr) */
if (skb_cow_head(skb, VXLAN_HEADROOM))
Expand Down Expand Up @@ -1019,6 +1197,10 @@ static const struct nla_policy vxlan_policy[IFLA_VXLAN_MAX + 1] = {
[IFLA_VXLAN_AGEING] = { .type = NLA_U32 },
[IFLA_VXLAN_LIMIT] = { .type = NLA_U32 },
[IFLA_VXLAN_PORT_RANGE] = { .len = sizeof(struct ifla_vxlan_port_range) },
[IFLA_VXLAN_PROXY] = { .type = NLA_U8 },
[IFLA_VXLAN_RSC] = { .type = NLA_U8 },
[IFLA_VXLAN_L2MISS] = { .type = NLA_U8 },
[IFLA_VXLAN_L3MISS] = { .type = NLA_U8 },
};

static int vxlan_validate(struct nlattr *tb[], struct nlattr *data[])
Expand Down Expand Up @@ -1114,13 +1296,25 @@ static int vxlan_newlink(struct net *net, struct net_device *dev,
vxlan->ttl = nla_get_u8(data[IFLA_VXLAN_TTL]);

if (!data[IFLA_VXLAN_LEARNING] || nla_get_u8(data[IFLA_VXLAN_LEARNING]))
vxlan->learn = true;
vxlan->flags |= VXLAN_F_LEARN;

if (data[IFLA_VXLAN_AGEING])
vxlan->age_interval = nla_get_u32(data[IFLA_VXLAN_AGEING]);
else
vxlan->age_interval = FDB_AGE_DEFAULT;

if (data[IFLA_VXLAN_PROXY] && nla_get_u8(data[IFLA_VXLAN_PROXY]))
vxlan->flags |= VXLAN_F_PROXY;

if (data[IFLA_VXLAN_RSC] && nla_get_u8(data[IFLA_VXLAN_RSC]))
vxlan->flags |= VXLAN_F_RSC;

if (data[IFLA_VXLAN_L2MISS] && nla_get_u8(data[IFLA_VXLAN_L2MISS]))
vxlan->flags |= VXLAN_F_L2MISS;

if (data[IFLA_VXLAN_L3MISS] && nla_get_u8(data[IFLA_VXLAN_L3MISS]))
vxlan->flags |= VXLAN_F_L3MISS;

if (data[IFLA_VXLAN_LIMIT])
vxlan->addrmax = nla_get_u32(data[IFLA_VXLAN_LIMIT]);

Expand Down Expand Up @@ -1157,6 +1351,10 @@ static size_t vxlan_get_size(const struct net_device *dev)
nla_total_size(sizeof(__u8)) + /* IFLA_VXLAN_TTL */
nla_total_size(sizeof(__u8)) + /* IFLA_VXLAN_TOS */
nla_total_size(sizeof(__u8)) + /* IFLA_VXLAN_LEARNING */
nla_total_size(sizeof(__u8)) + /* IFLA_VXLAN_PROXY */
nla_total_size(sizeof(__u8)) + /* IFLA_VXLAN_RSC */
nla_total_size(sizeof(__u8)) + /* IFLA_VXLAN_L2MISS */
nla_total_size(sizeof(__u8)) + /* IFLA_VXLAN_L3MISS */
nla_total_size(sizeof(__u32)) + /* IFLA_VXLAN_AGEING */
nla_total_size(sizeof(__u32)) + /* IFLA_VXLAN_LIMIT */
nla_total_size(sizeof(struct ifla_vxlan_port_range)) +
Expand Down Expand Up @@ -1185,7 +1383,15 @@ static int vxlan_fill_info(struct sk_buff *skb, const struct net_device *dev)

if (nla_put_u8(skb, IFLA_VXLAN_TTL, vxlan->ttl) ||
nla_put_u8(skb, IFLA_VXLAN_TOS, vxlan->tos) ||
nla_put_u8(skb, IFLA_VXLAN_LEARNING, vxlan->learn) ||
nla_put_u8(skb, IFLA_VXLAN_LEARNING,
!!(vxlan->flags & VXLAN_F_LEARN)) ||
nla_put_u8(skb, IFLA_VXLAN_PROXY,
!!(vxlan->flags & VXLAN_F_PROXY)) ||
nla_put_u8(skb, IFLA_VXLAN_RSC, !!(vxlan->flags & VXLAN_F_RSC)) ||
nla_put_u8(skb, IFLA_VXLAN_L2MISS,
!!(vxlan->flags & VXLAN_F_L2MISS)) ||
nla_put_u8(skb, IFLA_VXLAN_L3MISS,
!!(vxlan->flags & VXLAN_F_L3MISS)) ||
nla_put_u32(skb, IFLA_VXLAN_AGEING, vxlan->age_interval) ||
nla_put_u32(skb, IFLA_VXLAN_LIMIT, vxlan->addrmax))
goto nla_put_failure;
Expand Down
4 changes: 4 additions & 0 deletions include/uapi/linux/if_link.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -302,6 +302,10 @@ enum {
IFLA_VXLAN_AGEING,
IFLA_VXLAN_LIMIT,
IFLA_VXLAN_PORT_RANGE,
IFLA_VXLAN_PROXY,
IFLA_VXLAN_RSC,
IFLA_VXLAN_L2MISS,
IFLA_VXLAN_L3MISS,
__IFLA_VXLAN_MAX
};
#define IFLA_VXLAN_MAX (__IFLA_VXLAN_MAX - 1)
Expand Down

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