Hi,
After struggling with various userland VPN solutions for a while (and
failing to make IPSEC tunnel mode do what I want), I decided to just
implement ethernet-in-IP tunneling in the kernel and let IPSEC transport
mode handle the rest.
There appeared to be an RFC for ethernet-in-IP already, RFC 3378, so I
just implemented that. It's very simple -- slap a 16-bit header (0x3000,
which is 4 bits of etherip version number and 12 bits of padding) onto
the beginning of the ethernet packet, and then wrap it in an IP packet.
Below is what I came up with, against the latest Fedora Core 3 kernel,
which is 2.6.10-something. It survives some fairly basic testing between
a number of different machines, UP and SMP. (Corresponding iproute2
patch is available from http://www.wantstofly.org/~buytenh/etherip/ )
Notes:
- daddr=0 tunnel mode is meaningless for generic ethernet tunneling,
so I didn't implement that. Packets are just dropped on the floor
if daddr==0 at the time of sending, which is the default mode for
the etherip0 device.
Issues and TODO:
- Implement MULTICAST(daddr) tunnel mode, seems useful to have.
- Perhaps we should always present a MTU=1500 device to the user and
deal with fragmentation issues ourselves.
- Don't take TTL of outer packet from inner packet.
- Figure out what to do with DF.
- Check whether ECN bits are correctly {en,de}capsulated.
- Check out iffy-looking '2 * sizeof(struct etheriphdr)' construct
(same problem in ip_gre.c?)
Comments? I would like to see this upstream when the remaining issues
have been sorted out.
cheers,
Lennert
diff -urN linux-2.6.10.orig/include/linux/in.h linux-2.6.10/include/linux/in.h
--- linux-2.6.10.orig/include/linux/in.h 2005-01-12 21:44:31.000000000
+0100
+++ linux-2.6.10/include/linux/in.h 2005-01-12 21:44:28.000000000 +0100
@@ -39,6 +39,7 @@
IPPROTO_ESP = 50, /* Encapsulation Security Payload protocol */
IPPROTO_AH = 51, /* Authentication Header protocol */
+ IPPROTO_ETHERIP = 97, /* Ethernet-in-IP tunneling (rfc 3378)
*/
IPPROTO_PIM = 103, /* Protocol Independent Multicast
*/
IPPROTO_COMP = 108, /* Compression Header protocol */
diff -urN linux-2.6.10.orig/net/ipv4/etherip.c linux-2.6.10/net/ipv4/etherip.c
--- linux-2.6.10.orig/net/ipv4/etherip.c 1970-01-01 01:00:00.000000000
+0100
+++ linux-2.6.10/net/ipv4/etherip.c 2005-01-12 22:09:51.699077165 +0100
@@ -0,0 +1,758 @@
+/*
+ * Linux NET3: Ethernet over IP protocol decoder.
+ *
+ * Authors: Alexey Kuznetsov (kuznet@xxxxxxxxxxxxx)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ */
+
+/*
+ This version of net/ipv4/etherip.c created by Lennert Buytenhek
+ by mashing net/ipv4/ip_gre.c and net/ipv4/ipip.c together.
+
+ For comments look at net/ipv4/ip_gre.c
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <asm/uaccess.h>
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <linux/in.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
+#include <linux/if_arp.h>
+#include <linux/mroute.h>
+#include <linux/init.h>
+#include <linux/in6.h>
+#include <linux/inetdevice.h>
+#include <linux/igmp.h>
+#include <linux/netfilter_ipv4.h>
+#include <linux/etherdevice.h>
+
+#include <net/sock.h>
+#include <net/ip.h>
+#include <net/icmp.h>
+#include <net/protocol.h>
+#include <net/ipip.h>
+#include <net/arp.h>
+#include <net/checksum.h>
+#include <net/dsfield.h>
+#include <net/inet_ecn.h>
+#include <net/xfrm.h>
+
+#ifdef CONFIG_IPV6
+#include <net/ipv6.h>
+#include <net/ip6_fib.h>
+#include <net/ip6_route.h>
+#endif
+
+struct etheriphdr
+{
+ struct iphdr iph;
+ u16 version;
+} __attribute__((packed));
+
+#define HASH_SIZE 16
+#define HASH(addr) ((addr^(addr>>4))&0xF)
+
+#define ETHERIP_VERSION 0x3000
+
+static int etherip_fb_tunnel_init(struct net_device *dev);
+static int etherip_tunnel_init(struct net_device *dev);
+static void etherip_tunnel_setup(struct net_device *dev);
+
+static struct net_device *etherip_fb_tunnel_dev;
+
+static struct ip_tunnel *tunnels_r_l[HASH_SIZE];
+static struct ip_tunnel *tunnels_r[HASH_SIZE];
+static struct ip_tunnel *tunnels_l[HASH_SIZE];
+static struct ip_tunnel *tunnels_wc[1];
+
+static struct ip_tunnel **tunnels[4] = { tunnels_wc, tunnels_l, tunnels_r,
tunnels_r_l };
+
+static rwlock_t etherip_lock = RW_LOCK_UNLOCKED;
+
+static struct ip_tunnel * etherip_tunnel_lookup(u32 remote, u32 local)
+{
+ unsigned h0 = HASH(remote);
+ unsigned h1 = HASH(local);
+ struct ip_tunnel *t;
+
+ for (t = tunnels_r_l[h0^h1]; t; t = t->next) {
+ if (local == t->parms.iph.saddr &&
+ remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
+ return t;
+ }
+ for (t = tunnels_r[h0]; t; t = t->next) {
+ if (remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
+ return t;
+ }
+ for (t = tunnels_l[h1]; t; t = t->next) {
+ if (local == t->parms.iph.saddr && (t->dev->flags&IFF_UP))
+ return t;
+ }
+ if ((t = tunnels_wc[0]) != NULL && (t->dev->flags&IFF_UP))
+ return t;
+ return NULL;
+}
+
+static struct ip_tunnel **etherip_bucket(struct ip_tunnel *t)
+{
+ u32 remote = t->parms.iph.daddr;
+ u32 local = t->parms.iph.saddr;
+ unsigned h = 0;
+ int prio = 0;
+
+ if (remote) {
+ prio |= 2;
+ h ^= HASH(remote);
+ }
+ if (local) {
+ prio |= 1;
+ h ^= HASH(local);
+ }
+ return &tunnels[prio][h];
+}
+
+static void etherip_tunnel_unlink(struct ip_tunnel *t)
+{
+ struct ip_tunnel **tp;
+
+ for (tp = etherip_bucket(t); *tp; tp = &(*tp)->next) {
+ if (t == *tp) {
+ write_lock_bh(ðerip_lock);
+ *tp = t->next;
+ write_unlock_bh(ðerip_lock);
+ break;
+ }
+ }
+}
+
+static void etherip_tunnel_link(struct ip_tunnel *t)
+{
+ struct ip_tunnel **tp = etherip_bucket(t);
+
+ t->next = *tp;
+ write_lock_bh(ðerip_lock);
+ *tp = t;
+ write_unlock_bh(ðerip_lock);
+}
+
+static struct ip_tunnel * etherip_tunnel_locate(struct ip_tunnel_parm *parms,
int create)
+{
+ u32 remote = parms->iph.daddr;
+ u32 local = parms->iph.saddr;
+ struct ip_tunnel *t, **tp, *nt;
+ struct net_device *dev;
+ unsigned h = 0;
+ int prio = 0;
+ char name[IFNAMSIZ];
+
+ if (remote) {
+ prio |= 2;
+ h ^= HASH(remote);
+ }
+ if (local) {
+ prio |= 1;
+ h ^= HASH(local);
+ }
+ for (tp = &tunnels[prio][h]; (t = *tp) != NULL; tp = &t->next) {
+ if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr)
+ return t;
+ }
+ if (!create)
+ return NULL;
+
+ if (parms->name[0])
+ strlcpy(name, parms->name, IFNAMSIZ);
+ else {
+ int i;
+ for (i=1; i<100; i++) {
+ sprintf(name, "etherip%d", i);
+ if (__dev_get_by_name(name) == NULL)
+ break;
+ }
+ if (i==100)
+ goto failed;
+ }
+
+ dev = alloc_netdev(sizeof(*t), name, etherip_tunnel_setup);
+ if (!dev)
+ return NULL;
+
+ nt = dev->priv;
+ SET_MODULE_OWNER(dev);
+ dev->init = etherip_tunnel_init;
+ nt->parms = *parms;
+
+ if (register_netdevice(dev) < 0) {
+ free_netdev(dev);
+ goto failed;
+ }
+
+ dev_hold(dev);
+ etherip_tunnel_link(nt);
+ /* Do not decrement MOD_USE_COUNT here. */
+ return nt;
+
+failed:
+ return NULL;
+}
+
+static void etherip_tunnel_uninit(struct net_device *dev)
+{
+ if (dev == etherip_fb_tunnel_dev) {
+ write_lock_bh(ðerip_lock);
+ tunnels_wc[0] = NULL;
+ write_unlock_bh(ðerip_lock);
+ } else
+ etherip_tunnel_unlink((struct ip_tunnel*)dev->priv);
+ dev_put(dev);
+}
+
+
+void etherip_err(struct sk_buff *skb, u32 info)
+{
+#ifndef I_WISH_WORLD_WERE_PERFECT
+/* It is not :-( All the routers (except for Linux) return only
+ 8 bytes of packet payload. It means, that precise relaying of
+ ICMP in the real Internet is absolutely infeasible.
+ */
+
+ struct iphdr *iph = (struct iphdr*)skb->data;
+ int type = skb->h.icmph->type;
+ int code = skb->h.icmph->code;
+ struct ip_tunnel *t;
+
+ switch (type) {
+ default:
+ case ICMP_PARAMETERPROB:
+ return;
+
+ case ICMP_DEST_UNREACH:
+ switch (code) {
+ case ICMP_SR_FAILED:
+ case ICMP_PORT_UNREACH:
+ /* Impossible event. */
+ return;
+ case ICMP_FRAG_NEEDED:
+ /* Soft state for pmtu is maintained by IP core. */
+ return;
+ default:
+ /* All others are translated to HOST_UNREACH.
+ rfc2003 contains "deep thoughts" about NET_UNREACH,
+ I believe they are just ether pollution. --ANK
+ */
+ break;
+ }
+ break;
+ case ICMP_TIME_EXCEEDED:
+ if (code != ICMP_EXC_TTL)
+ return;
+ break;
+ }
+
+ read_lock(ðerip_lock);
+ t = etherip_tunnel_lookup(iph->daddr, iph->saddr);
+ if (t == NULL || t->parms.iph.daddr == 0)
+ goto out;
+ if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
+ goto out;
+
+ if (jiffies - t->err_time < IPTUNNEL_ERR_TIMEO)
+ t->err_count++;
+ else
+ t->err_count = 1;
+ t->err_time = jiffies;
+out:
+ read_unlock(ðerip_lock);
+ return;
+#endif
+}
+
+static inline void etherip_ecn_decapsulate(struct iphdr *iph, struct sk_buff
*skb)
+{
+ if (INET_ECN_is_ce(iph->tos)) {
+ if (skb->protocol == htons(ETH_P_IP)) {
+ IP_ECN_set_ce(skb->nh.iph);
+ } else if (skb->protocol == htons(ETH_P_IPV6)) {
+ IP6_ECN_set_ce(skb->nh.ipv6h);
+ }
+ }
+}
+
+static inline u8
+etherip_ecn_encapsulate(u8 tos, struct iphdr *old_iph, struct sk_buff *skb)
+{
+ u8 inner = 0;
+ if (skb->protocol == htons(ETH_P_IP))
+ inner = old_iph->tos;
+ else if (skb->protocol == htons(ETH_P_IPV6))
+ inner = ipv6_get_dsfield((struct ipv6hdr *)old_iph);
+ return INET_ECN_encapsulate(tos, inner);
+}
+
+int etherip_rcv(struct sk_buff *skb)
+{
+ struct iphdr *iph;
+ struct ip_tunnel *tunnel;
+ struct etheriphdr *ethiph;
+
+ if (!pskb_may_pull(skb, sizeof(struct etheriphdr)))
+ goto out;
+
+ ethiph = (struct etheriphdr *)skb->nh.raw;
+ if (ethiph->version != htons(ETHERIP_VERSION)) {
+ kfree_skb(skb);
+ return 0;
+ }
+
+ iph = skb->nh.iph;
+
+ read_lock(ðerip_lock);
+ if ((tunnel = etherip_tunnel_lookup(iph->saddr, iph->daddr)) != NULL) {
+ secpath_reset(skb);
+
+ /* Pull etherip header. */
+ skb_pull(skb, 2);
+ skb->protocol = eth_type_trans(skb, tunnel->dev);
+
+ memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
+
+ tunnel->stat.rx_packets++;
+ tunnel->stat.rx_bytes += skb->len;
+ skb->dev = tunnel->dev;
+ dst_release(skb->dst);
+ skb->dst = NULL;
+ nf_reset(skb);
+ etherip_ecn_decapsulate(iph, skb);
+ netif_rx(skb);
+ read_unlock(ðerip_lock);
+ return 0;
+ }
+ read_unlock(ðerip_lock);
+
+out:
+ return -1;
+}
+
+static int etherip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+ struct ip_tunnel *tunnel = (struct ip_tunnel*)dev->priv;
+ struct net_device_stats *stats = &tunnel->stat;
+ struct iphdr *old_iph = skb->nh.iph;
+ struct iphdr *tiph = &tunnel->parms.iph;
+ u8 tos;
+ u16 df;
+ struct rtable *rt; /* Route to the other host */
+ struct net_device *tdev; /* Device to other host */
+ struct etheriphdr *ethiph;
+ struct iphdr *iph; /* Our new IP header */
+ int max_headroom; /* The extra header space needed */
+ int mtu;
+
+ if (tunnel->recursion++) {
+ stats->collisions++;
+ goto tx_error;
+ }
+
+ /* Need valid non-multicast daddr. */
+ if (tiph->daddr == 0 || MULTICAST(tiph->daddr))
+ goto tx_error;
+
+ tos = tiph->tos;
+ if (tos&1) {
+ if (skb->protocol == htons(ETH_P_IP))
+ tos = old_iph->tos;
+ tos &= ~1;
+ }
+
+ {
+ struct flowi fl = { .oif = tunnel->parms.link,
+ .nl_u = { .ip4_u =
+ { .daddr = tiph->daddr,
+ .saddr = tiph->saddr,
+ .tos = RT_TOS(tos) } },
+ .proto = IPPROTO_ETHERIP };
+ if (ip_route_output_key(&rt, &fl)) {
+ stats->tx_carrier_errors++;
+ goto tx_error_icmp;
+ }
+ }
+ tdev = rt->u.dst.dev;
+
+ if (tdev == dev) {
+ ip_rt_put(rt);
+ stats->collisions++;
+ goto tx_error;
+ }
+
+ df = tiph->frag_off;
+ if (df)
+ mtu = dst_pmtu(&rt->u.dst) - sizeof(struct etheriphdr);
+ else
+ mtu = skb->dst ? dst_pmtu(skb->dst) : dev->mtu;
+
+ if (skb->dst)
+ skb->dst->ops->update_pmtu(skb->dst, mtu);
+
+ if (skb->protocol == htons(ETH_P_IP)) {
+ df |= (old_iph->frag_off&htons(IP_DF));
+
+ if ((old_iph->frag_off & htons(IP_DF)) &&
+ mtu < ntohs(old_iph->tot_len)) {
+ icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
htonl(mtu));
+ ip_rt_put(rt);
+ goto tx_error;
+ }
+ }
+#ifdef CONFIG_IPV6
+ else if (skb->protocol == htons(ETH_P_IPV6)) {
+ struct rt6_info *rt6 = (struct rt6_info*)skb->dst;
+
+ if (rt6 && mtu < dst_pmtu(skb->dst) && mtu >= IPV6_MIN_MTU) {
+ if (tiph->daddr || rt6->rt6i_dst.plen == 128) {
+ rt6->rt6i_flags |= RTF_MODIFIED;
+ skb->dst->metrics[RTAX_MTU-1] = mtu;
+ }
+ }
+
+ /* @@@ Is this correct? */
+ if (mtu >= IPV6_MIN_MTU && mtu < skb->len - 2 * sizeof(struct
etheriphdr)) {
+ icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
+ ip_rt_put(rt);
+ goto tx_error;
+ }
+ }
+#endif
+
+ if (tunnel->err_count > 0) {
+ if (jiffies - tunnel->err_time < IPTUNNEL_ERR_TIMEO) {
+ tunnel->err_count--;
+ dst_link_failure(skb);
+ } else
+ tunnel->err_count = 0;
+ }
+
+ max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct etheriphdr);
+
+ if (skb_headroom(skb) < max_headroom || skb_cloned(skb) ||
skb_shared(skb)) {
+ struct sk_buff *new_skb = skb_realloc_headroom(skb,
max_headroom);
+ if (!new_skb) {
+ ip_rt_put(rt);
+ stats->tx_dropped++;
+ dev_kfree_skb(skb);
+ tunnel->recursion--;
+ return 0;
+ }
+ if (skb->sk)
+ skb_set_owner_w(new_skb, skb->sk);
+ dev_kfree_skb(skb);
+ skb = new_skb;
+ old_iph = skb->nh.iph;
+ }
+
+ skb->h.raw = skb->nh.raw;
+ skb->nh.raw = skb_push(skb, sizeof(struct etheriphdr));
+ memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
+ dst_release(skb->dst);
+ skb->dst = &rt->u.dst;
+
+ /*
+ * Push down and install the etherip header.
+ */
+
+ ethiph = (struct etheriphdr *)skb->nh.iph;
+
+ iph = ðiph->iph;
+ iph->version = 4;
+ iph->ihl = sizeof(struct iphdr) >> 2;
+ iph->frag_off = df;
+ iph->protocol = IPPROTO_ETHERIP;
+ iph->tos = etherip_ecn_encapsulate(tos, old_iph,
skb);
+ iph->daddr = rt->rt_dst;
+ iph->saddr = rt->rt_src;
+
+ ethiph->version = htons(ETHERIP_VERSION);
+
+ if ((ethiph->iph.ttl = tiph->ttl) == 0) {
+ if (skb->protocol == htons(ETH_P_IP))
+ ethiph->iph.ttl = old_iph->ttl;
+#ifdef CONFIG_IPV6
+ else if (skb->protocol == htons(ETH_P_IPV6))
+ ethiph->iph.ttl = ((struct ipv6hdr*)old_iph)->hop_limit;
+#endif
+ else
+ ethiph->iph.ttl = dst_metric(&rt->u.dst, RTAX_HOPLIMIT);
+ }
+
+ nf_reset(skb);
+
+ IPTUNNEL_XMIT();
+ tunnel->recursion--;
+ return 0;
+
+tx_error_icmp:
+ dst_link_failure(skb);
+
+tx_error:
+ stats->tx_errors++;
+ dev_kfree_skb(skb);
+ tunnel->recursion--;
+ return 0;
+}
+
+static int
+etherip_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
+{
+ int err = 0;
+ struct ip_tunnel_parm p;
+ struct ip_tunnel *t;
+
+ switch (cmd) {
+ case SIOCGETTUNNEL:
+ t = NULL;
+ if (dev == etherip_fb_tunnel_dev) {
+ if (copy_from_user(&p, ifr->ifr_ifru.ifru_data,
sizeof(p))) {
+ err = -EFAULT;
+ break;
+ }
+ t = etherip_tunnel_locate(&p, 0);
+ }
+ if (t == NULL)
+ t = (struct ip_tunnel*)dev->priv;
+ memcpy(&p, &t->parms, sizeof(p));
+ if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
+ err = -EFAULT;
+ break;
+
+ case SIOCADDTUNNEL:
+ case SIOCCHGTUNNEL:
+ err = -EPERM;
+ if (!capable(CAP_NET_ADMIN))
+ goto done;
+
+ err = -EFAULT;
+ if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
+ goto done;
+
+ err = -EINVAL;
+ if (p.iph.version != 4 || p.iph.protocol != IPPROTO_ETHERIP ||
+ p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
+ goto done;
+ if (p.iph.ttl)
+ p.iph.frag_off |= htons(IP_DF);
+
+ t = etherip_tunnel_locate(&p, cmd == SIOCADDTUNNEL);
+
+ if (dev != etherip_fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
+ if (t != NULL) {
+ if (t->dev != dev) {
+ err = -EEXIST;
+ break;
+ }
+ } else {
+ if (!p.iph.daddr) {
+ err = -EINVAL;
+ break;
+ }
+
+ t = (struct ip_tunnel*)dev->priv;
+ etherip_tunnel_unlink(t);
+ t->parms.iph.saddr = p.iph.saddr;
+ t->parms.iph.daddr = p.iph.daddr;
+ etherip_tunnel_link(t);
+ netdev_state_change(dev);
+ }
+ }
+
+ if (t) {
+ err = 0;
+ if (cmd == SIOCCHGTUNNEL) {
+ t->parms.iph.ttl = p.iph.ttl;
+ t->parms.iph.tos = p.iph.tos;
+ t->parms.iph.frag_off = p.iph.frag_off;
+ }
+ if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms,
sizeof(p)))
+ err = -EFAULT;
+ } else
+ err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
+ break;
+
+ case SIOCDELTUNNEL:
+ err = -EPERM;
+ if (!capable(CAP_NET_ADMIN))
+ goto done;
+
+ if (dev == etherip_fb_tunnel_dev) {
+ err = -EFAULT;
+ if (copy_from_user(&p, ifr->ifr_ifru.ifru_data,
sizeof(p)))
+ goto done;
+ err = -ENOENT;
+ if ((t = etherip_tunnel_locate(&p, 0)) == NULL)
+ goto done;
+ err = -EPERM;
+ if (t->dev == etherip_fb_tunnel_dev)
+ goto done;
+ dev = t->dev;
+ }
+ err = unregister_netdevice(dev);
+ break;
+
+ default:
+ err = -EINVAL;
+ }
+
+done:
+ return err;
+}
+
+static struct net_device_stats *etherip_tunnel_get_stats(struct net_device
*dev)
+{
+ return &(((struct ip_tunnel*)dev->priv)->stat);
+}
+
+static int etherip_tunnel_change_mtu(struct net_device *dev, int new_mtu)
+{
+ if (new_mtu < 68 || new_mtu > 0xFFF8 - sizeof(struct etheriphdr))
+ return -EINVAL;
+ dev->mtu = new_mtu;
+ return 0;
+}
+
+static void etherip_tunnel_setup(struct net_device *dev)
+{
+ SET_MODULE_OWNER(dev);
+ ether_setup(dev);
+
+ dev->uninit = etherip_tunnel_uninit;
+ dev->destructor = free_netdev;
+ dev->hard_start_xmit = etherip_tunnel_xmit;
+ dev->get_stats = etherip_tunnel_get_stats;
+ dev->do_ioctl = etherip_tunnel_ioctl;
+ dev->change_mtu = etherip_tunnel_change_mtu;
+
+ dev->hard_header_len = ETH_HLEN; // + sizeof(struct etheriphdr);
+ dev->tx_queue_len = 0;
+ random_ether_addr(dev->dev_addr);
+
+ dev->iflink = 0;
+}
+
+static int etherip_tunnel_init(struct net_device *dev)
+{
+ struct net_device *tdev = NULL;
+ struct ip_tunnel *tunnel;
+ struct iphdr *iph;
+
+ tunnel = (struct ip_tunnel*)dev->priv;
+ iph = &tunnel->parms.iph;
+
+ tunnel->dev = dev;
+ strcpy(tunnel->parms.name, dev->name);
+
+ /* Guess output device to choose reasonable mtu and hard_header_len */
+ if (iph->daddr) {
+ struct flowi fl = { .oif = tunnel->parms.link,
+ .nl_u = { .ip4_u =
+ { .daddr = iph->daddr,
+ .saddr = iph->saddr,
+ .tos = RT_TOS(iph->tos) } },
+ .proto = IPPROTO_ETHERIP };
+ struct rtable *rt;
+ if (!ip_route_output_key(&rt, &fl)) {
+ tdev = rt->u.dst.dev;
+ ip_rt_put(rt);
+ }
+ }
+
+ if (!tdev && tunnel->parms.link)
+ tdev = __dev_get_by_index(tunnel->parms.link);
+
+ if (tdev) {
+ dev->hard_header_len = tdev->hard_header_len + sizeof(struct
etheriphdr);
+ dev->mtu = tdev->mtu - sizeof(struct etheriphdr);
+ }
+ dev->iflink = tunnel->parms.link;
+
+ return 0;
+}
+
+int __init etherip_fb_tunnel_init(struct net_device *dev)
+{
+ struct ip_tunnel *tunnel = (struct ip_tunnel*)dev->priv;
+ struct iphdr *iph = &tunnel->parms.iph;
+
+ tunnel->dev = dev;
+ strcpy(tunnel->parms.name, dev->name);
+
+ iph->version = 4;
+ iph->protocol = IPPROTO_ETHERIP;
+ iph->ihl = 5;
+
+ dev_hold(dev);
+ tunnels_wc[0] = tunnel;
+ return 0;
+}
+
+
+static struct net_protocol etherip_protocol = {
+ .handler = etherip_rcv,
+ .err_handler = etherip_err,
+};
+
+
+/*
+ * And now the modules code and kernel interface.
+ */
+
+static int __init etherip_init(void)
+{
+ int err;
+
+ printk(KERN_INFO "Ethernet over IPv4 tunneling driver\n");
+
+ if (inet_add_protocol(ðerip_protocol, IPPROTO_ETHERIP) < 0) {
+ printk(KERN_INFO "etherip init: can't add protocol\n");
+ return -EAGAIN;
+ }
+
+ etherip_fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel),
+ "etherip0", etherip_tunnel_setup);
+ if (!etherip_fb_tunnel_dev) {
+ err = -ENOMEM;
+ goto err1;
+ }
+
+ etherip_fb_tunnel_dev->init = etherip_fb_tunnel_init;
+
+ if ((err = register_netdev(etherip_fb_tunnel_dev)))
+ goto err2;
+out:
+ return err;
+err2:
+ free_netdev(etherip_fb_tunnel_dev);
+err1:
+ inet_del_protocol(ðerip_protocol, IPPROTO_ETHERIP);
+ goto out;
+}
+
+void etherip_fini(void)
+{
+ if (inet_del_protocol(ðerip_protocol, IPPROTO_ETHERIP) < 0)
+ printk(KERN_INFO "etherip close: can't remove protocol\n");
+
+ unregister_netdev(etherip_fb_tunnel_dev);
+}
+
+module_init(etherip_init);
+module_exit(etherip_fini);
+MODULE_LICENSE("GPL");
diff -urN linux-2.6.10.orig/net/ipv4/Kconfig linux-2.6.10/net/ipv4/Kconfig
--- linux-2.6.10.orig/net/ipv4/Kconfig 2005-01-12 21:48:11.000000000 +0100
+++ linux-2.6.10/net/ipv4/Kconfig 2005-01-12 21:53:51.063081266 +0100
@@ -202,6 +202,15 @@
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_ETHERIP
+ tristate "IP: ethernet-in-IP tunneling"
+ depends on INET
+ help
+ Tunneling means encapsulating data of one protocol type within
+ another protocol and sending it over a channel that understands the
+ encapsulating protocol. This particular tunneling driver implements
+ the etherip Ethernet-in-IP protocol as described in RFC 3378.
+
config IP_MROUTE
bool "IP: multicast routing"
depends on IP_MULTICAST
diff -urN linux-2.6.10.orig/net/ipv4/Makefile linux-2.6.10/net/ipv4/Makefile
--- linux-2.6.10.orig/net/ipv4/Makefile 2004-12-24 22:34:26.000000000 +0100
+++ linux-2.6.10/net/ipv4/Makefile 2005-01-12 21:48:38.762364033 +0100
@@ -14,6 +14,7 @@
obj-$(CONFIG_IP_MROUTE) += ipmr.o
obj-$(CONFIG_NET_IPIP) += ipip.o
obj-$(CONFIG_NET_IPGRE) += ip_gre.o
+obj-$(CONFIG_NET_ETHERIP) += etherip.o
obj-$(CONFIG_SYN_COOKIES) += syncookies.o
obj-$(CONFIG_INET_AH) += ah4.o
obj-$(CONFIG_INET_ESP) += esp4.o
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