[PATCH net-next] add DOVE extensions for VXLAN
From: David L Stevens <hidden>
Date: 2012-11-13 20:28:02
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 Signed-off-by: David L Stevens <redacted>
diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 8aca888..42ccd54 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c@@ -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>
@@ -111,6 +113,7 @@ struct vxlan_dev { __u8 tos; /* TOS override */ __u8 ttl; bool learn; + bool dove; unsigned long age_interval; struct timer_list age_timer;
@@ -155,6 +158,7 @@ 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)
@@ -162,16 +166,28 @@ static int vxlan_fdb_info(struct sk_buff *skb, struct vxlan_dev *vxlan, ndm = nlmsg_data(nlh); memset(ndm, 0, sizeof(*ndm)); - ndm->ndm_family = AF_BRIDGE; + + send_eth = send_ip = true; + + if (type == RTM_GETNEIGH) { + int i; + + ndm->ndm_family = AF_INET; + send_ip = fdb->remote_ip != 0; + send_eth = 0; + for (i=0; i<ETH_ALEN; ++i) + send_eth |= !!fdb->eth_addr[i]; + } 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);
@@ -223,6 +239,29 @@ errout: 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) {
@@ -552,6 +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);
@@ -600,6 +641,115 @@ drop: return 0; } +static int arp_reduce(struct net_device *dev, struct sk_buff *skb) +{ + 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 + 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 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 + 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)
@@ -622,22 +772,6 @@ 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);
@@ -684,6 +818,7 @@ 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;
@@ -694,10 +829,57 @@ static netdev_tx_t vxlan_xmit(struct sk_buff *skb, struct net_device *dev) __be16 df = 0; __u8 tos, ttl; int err; + bool rsc = false; + const struct vxlan_fdb *f; - dst = vxlan_find_dst(vxlan, skb); - if (!dst) + skb_reset_mac_header(skb); + eth = eth_hdr(skb); + + if (vxlan->dove) { + switch (ntohs(eth->h_proto)) { + case ETH_P_ARP: + return arp_reduce(dev, skb); + case ETH_P_IP: + rsc = route_shortcircuit(dev, skb); + break; + default: + break; + } + } + + f = vxlan_find_mac(vxlan, eth->h_dest); + if (f == NULL) { + rsc = false; + dst = vxlan->gaddr; + if (!dst && vxlan->dove && + !is_multicast_ether_addr(eth->h_dest)) + vxlan_fdb_miss(vxlan, eth->h_dest); + } else + dst = f->remote_ip; + + if (!dst) { + if (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))
@@ -1020,6 +1202,7 @@ 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_DOVE] = { .type = NLA_U8 }, }; static int vxlan_validate(struct nlattr *tb[], struct nlattr *data[])
@@ -1118,6 +1301,9 @@ static int vxlan_newlink(struct net *net, struct net_device *dev, else vxlan->age_interval = FDB_AGE_DEFAULT; + if (data[IFLA_VXLAN_DOVE] && nla_get_u8(data[IFLA_VXLAN_DOVE])) + vxlan->dove = true; + if (data[IFLA_VXLAN_LIMIT]) vxlan->addrmax = nla_get_u32(data[IFLA_VXLAN_LIMIT]);
@@ -1154,6 +1340,7 @@ 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(__u32)) + /* IFLA_VXLAN_DOVE */ 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)) +
@@ -1183,6 +1370,7 @@ 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_DOVE, vxlan->dove) || nla_put_u32(skb, IFLA_VXLAN_AGEING, vxlan->age_interval) || nla_put_u32(skb, IFLA_VXLAN_LIMIT, vxlan->addrmax)) goto nla_put_failure;
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 5c80cb1..740b636 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h@@ -285,6 +285,7 @@ enum { IFLA_VXLAN_AGEING, IFLA_VXLAN_LIMIT, IFLA_VXLAN_PORT_RANGE, + IFLA_VXLAN_DOVE, __IFLA_VXLAN_MAX }; #define IFLA_VXLAN_MAX (__IFLA_VXLAN_MAX - 1)