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-rw-r--r--net/ipv6/sit.c833
1 files changed, 833 insertions, 0 deletions
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
new file mode 100644
index 000000000000..b788f55e139b
--- /dev/null
+++ b/net/ipv6/sit.c
@@ -0,0 +1,833 @@
+/*
+ * IPv6 over IPv4 tunnel device - Simple Internet Transition (SIT)
+ * Linux INET6 implementation
+ *
+ * Authors:
+ * Pedro Roque <roque@di.fc.ul.pt>
+ * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
+ *
+ * $Id: sit.c,v 1.53 2001/09/25 05:09:53 davem Exp $
+ *
+ * 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.
+ *
+ * Changes:
+ * Roger Venning <r.venning@telstra.com>: 6to4 support
+ * Nate Thompson <nate@thebog.net>: 6to4 support
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/sockios.h>
+#include <linux/sched.h>
+#include <linux/net.h>
+#include <linux/in6.h>
+#include <linux/netdevice.h>
+#include <linux/if_arp.h>
+#include <linux/icmp.h>
+#include <asm/uaccess.h>
+#include <linux/init.h>
+#include <linux/netfilter_ipv4.h>
+
+#include <net/sock.h>
+#include <net/snmp.h>
+
+#include <net/ipv6.h>
+#include <net/protocol.h>
+#include <net/transp_v6.h>
+#include <net/ip6_fib.h>
+#include <net/ip6_route.h>
+#include <net/ndisc.h>
+#include <net/addrconf.h>
+#include <net/ip.h>
+#include <net/udp.h>
+#include <net/icmp.h>
+#include <net/ipip.h>
+#include <net/inet_ecn.h>
+#include <net/xfrm.h>
+#include <net/dsfield.h>
+
+/*
+ This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c
+
+ For comments look at net/ipv4/ip_gre.c --ANK
+ */
+
+#define HASH_SIZE 16
+#define HASH(addr) ((addr^(addr>>4))&0xF)
+
+static int ipip6_fb_tunnel_init(struct net_device *dev);
+static int ipip6_tunnel_init(struct net_device *dev);
+static void ipip6_tunnel_setup(struct net_device *dev);
+
+static struct net_device *ipip6_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 DEFINE_RWLOCK(ipip6_lock);
+
+static struct ip_tunnel * ipip6_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 ** ipip6_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 ipip6_tunnel_unlink(struct ip_tunnel *t)
+{
+ struct ip_tunnel **tp;
+
+ for (tp = ipip6_bucket(t); *tp; tp = &(*tp)->next) {
+ if (t == *tp) {
+ write_lock_bh(&ipip6_lock);
+ *tp = t->next;
+ write_unlock_bh(&ipip6_lock);
+ break;
+ }
+ }
+}
+
+static void ipip6_tunnel_link(struct ip_tunnel *t)
+{
+ struct ip_tunnel **tp = ipip6_bucket(t);
+
+ t->next = *tp;
+ write_lock_bh(&ipip6_lock);
+ *tp = t;
+ write_unlock_bh(&ipip6_lock);
+}
+
+static struct ip_tunnel * ipip6_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)
+ goto failed;
+
+ if (parms->name[0])
+ strlcpy(name, parms->name, IFNAMSIZ);
+ else {
+ int i;
+ for (i=1; i<100; i++) {
+ sprintf(name, "sit%d", i);
+ if (__dev_get_by_name(name) == NULL)
+ break;
+ }
+ if (i==100)
+ goto failed;
+ }
+
+ dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
+ if (dev == NULL)
+ return NULL;
+
+ nt = dev->priv;
+ dev->init = ipip6_tunnel_init;
+ nt->parms = *parms;
+
+ if (register_netdevice(dev) < 0) {
+ free_netdev(dev);
+ goto failed;
+ }
+
+ dev_hold(dev);
+
+ ipip6_tunnel_link(nt);
+ /* Do not decrement MOD_USE_COUNT here. */
+ return nt;
+
+failed:
+ return NULL;
+}
+
+static void ipip6_tunnel_uninit(struct net_device *dev)
+{
+ if (dev == ipip6_fb_tunnel_dev) {
+ write_lock_bh(&ipip6_lock);
+ tunnels_wc[0] = NULL;
+ write_unlock_bh(&ipip6_lock);
+ dev_put(dev);
+ } else {
+ ipip6_tunnel_unlink((struct ip_tunnel*)dev->priv);
+ dev_put(dev);
+ }
+}
+
+
+static void ipip6_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(&ipip6_lock);
+ t = ipip6_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(&ipip6_lock);
+ return;
+#else
+ struct iphdr *iph = (struct iphdr*)dp;
+ int hlen = iph->ihl<<2;
+ struct ipv6hdr *iph6;
+ int type = skb->h.icmph->type;
+ int code = skb->h.icmph->code;
+ int rel_type = 0;
+ int rel_code = 0;
+ int rel_info = 0;
+ struct sk_buff *skb2;
+ struct rt6_info *rt6i;
+
+ if (len < hlen + sizeof(struct ipv6hdr))
+ return;
+ iph6 = (struct ipv6hdr*)(dp + hlen);
+
+ switch (type) {
+ default:
+ return;
+ case ICMP_PARAMETERPROB:
+ if (skb->h.icmph->un.gateway < hlen)
+ return;
+
+ /* So... This guy found something strange INSIDE encapsulated
+ packet. Well, he is fool, but what can we do ?
+ */
+ rel_type = ICMPV6_PARAMPROB;
+ rel_info = skb->h.icmph->un.gateway - hlen;
+ break;
+
+ case ICMP_DEST_UNREACH:
+ switch (code) {
+ case ICMP_SR_FAILED:
+ case ICMP_PORT_UNREACH:
+ /* Impossible event. */
+ return;
+ case ICMP_FRAG_NEEDED:
+ /* Too complicated case ... */
+ return;
+ default:
+ /* All others are translated to HOST_UNREACH.
+ rfc2003 contains "deep thoughts" about NET_UNREACH,
+ I believe, it is just ether pollution. --ANK
+ */
+ rel_type = ICMPV6_DEST_UNREACH;
+ rel_code = ICMPV6_ADDR_UNREACH;
+ break;
+ }
+ break;
+ case ICMP_TIME_EXCEEDED:
+ if (code != ICMP_EXC_TTL)
+ return;
+ rel_type = ICMPV6_TIME_EXCEED;
+ rel_code = ICMPV6_EXC_HOPLIMIT;
+ break;
+ }
+
+ /* Prepare fake skb to feed it to icmpv6_send */
+ skb2 = skb_clone(skb, GFP_ATOMIC);
+ if (skb2 == NULL)
+ return;
+ dst_release(skb2->dst);
+ skb2->dst = NULL;
+ skb_pull(skb2, skb->data - (u8*)iph6);
+ skb2->nh.raw = skb2->data;
+
+ /* Try to guess incoming interface */
+ rt6i = rt6_lookup(&iph6->saddr, NULL, NULL, 0);
+ if (rt6i && rt6i->rt6i_dev) {
+ skb2->dev = rt6i->rt6i_dev;
+
+ rt6i = rt6_lookup(&iph6->daddr, &iph6->saddr, NULL, 0);
+
+ if (rt6i && rt6i->rt6i_dev && rt6i->rt6i_dev->type == ARPHRD_SIT) {
+ struct ip_tunnel * t = (struct ip_tunnel*)rt6i->rt6i_dev->priv;
+ if (rel_type == ICMPV6_TIME_EXCEED && t->parms.iph.ttl) {
+ rel_type = ICMPV6_DEST_UNREACH;
+ rel_code = ICMPV6_ADDR_UNREACH;
+ }
+ icmpv6_send(skb2, rel_type, rel_code, rel_info, skb2->dev);
+ }
+ }
+ kfree_skb(skb2);
+ return;
+#endif
+}
+
+static inline void ipip6_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
+{
+ if (INET_ECN_is_ce(iph->tos))
+ IP6_ECN_set_ce(skb->nh.ipv6h);
+}
+
+static int ipip6_rcv(struct sk_buff *skb)
+{
+ struct iphdr *iph;
+ struct ip_tunnel *tunnel;
+
+ if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
+ goto out;
+
+ iph = skb->nh.iph;
+
+ read_lock(&ipip6_lock);
+ if ((tunnel = ipip6_tunnel_lookup(iph->saddr, iph->daddr)) != NULL) {
+ secpath_reset(skb);
+ skb->mac.raw = skb->nh.raw;
+ skb->nh.raw = skb->data;
+ memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
+ skb->protocol = htons(ETH_P_IPV6);
+ skb->pkt_type = PACKET_HOST;
+ tunnel->stat.rx_packets++;
+ tunnel->stat.rx_bytes += skb->len;
+ skb->dev = tunnel->dev;
+ dst_release(skb->dst);
+ skb->dst = NULL;
+ nf_reset(skb);
+ ipip6_ecn_decapsulate(iph, skb);
+ netif_rx(skb);
+ read_unlock(&ipip6_lock);
+ return 0;
+ }
+
+ icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PROT_UNREACH, 0);
+ kfree_skb(skb);
+ read_unlock(&ipip6_lock);
+out:
+ return 0;
+}
+
+/* Returns the embedded IPv4 address if the IPv6 address
+ comes from 6to4 (RFC 3056) addr space */
+
+static inline u32 try_6to4(struct in6_addr *v6dst)
+{
+ u32 dst = 0;
+
+ if (v6dst->s6_addr16[0] == htons(0x2002)) {
+ /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
+ memcpy(&dst, &v6dst->s6_addr16[1], 4);
+ }
+ return dst;
+}
+
+/*
+ * This function assumes it is being called from dev_queue_xmit()
+ * and that skb is filled properly by that function.
+ */
+
+static int ipip6_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 *tiph = &tunnel->parms.iph;
+ struct ipv6hdr *iph6 = skb->nh.ipv6h;
+ u8 tos = tunnel->parms.iph.tos;
+ struct rtable *rt; /* Route to the other host */
+ struct net_device *tdev; /* Device to other host */
+ struct iphdr *iph; /* Our new IP header */
+ int max_headroom; /* The extra header space needed */
+ u32 dst = tiph->daddr;
+ int mtu;
+ struct in6_addr *addr6;
+ int addr_type;
+
+ if (tunnel->recursion++) {
+ tunnel->stat.collisions++;
+ goto tx_error;
+ }
+
+ if (skb->protocol != htons(ETH_P_IPV6))
+ goto tx_error;
+
+ if (!dst)
+ dst = try_6to4(&iph6->daddr);
+
+ if (!dst) {
+ struct neighbour *neigh = NULL;
+
+ if (skb->dst)
+ neigh = skb->dst->neighbour;
+
+ if (neigh == NULL) {
+ if (net_ratelimit())
+ printk(KERN_DEBUG "sit: nexthop == NULL\n");
+ goto tx_error;
+ }
+
+ addr6 = (struct in6_addr*)&neigh->primary_key;
+ addr_type = ipv6_addr_type(addr6);
+
+ if (addr_type == IPV6_ADDR_ANY) {
+ addr6 = &skb->nh.ipv6h->daddr;
+ addr_type = ipv6_addr_type(addr6);
+ }
+
+ if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
+ goto tx_error_icmp;
+
+ dst = addr6->s6_addr32[3];
+ }
+
+ {
+ struct flowi fl = { .nl_u = { .ip4_u =
+ { .daddr = dst,
+ .saddr = tiph->saddr,
+ .tos = RT_TOS(tos) } },
+ .oif = tunnel->parms.link,
+ .proto = IPPROTO_IPV6 };
+ if (ip_route_output_key(&rt, &fl)) {
+ tunnel->stat.tx_carrier_errors++;
+ goto tx_error_icmp;
+ }
+ }
+ if (rt->rt_type != RTN_UNICAST) {
+ ip_rt_put(rt);
+ tunnel->stat.tx_carrier_errors++;
+ goto tx_error_icmp;
+ }
+ tdev = rt->u.dst.dev;
+
+ if (tdev == dev) {
+ ip_rt_put(rt);
+ tunnel->stat.collisions++;
+ goto tx_error;
+ }
+
+ if (tiph->frag_off)
+ mtu = dst_mtu(&rt->u.dst) - sizeof(struct iphdr);
+ else
+ mtu = skb->dst ? dst_mtu(skb->dst) : dev->mtu;
+
+ if (mtu < 68) {
+ tunnel->stat.collisions++;
+ ip_rt_put(rt);
+ goto tx_error;
+ }
+ if (mtu < IPV6_MIN_MTU)
+ mtu = IPV6_MIN_MTU;
+ if (tunnel->parms.iph.daddr && skb->dst)
+ skb->dst->ops->update_pmtu(skb->dst, mtu);
+
+ if (skb->len > mtu) {
+ icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
+ ip_rt_put(rt);
+ goto tx_error;
+ }
+
+ 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;
+ }
+
+ /*
+ * Okay, now see if we can stuff it in the buffer as-is.
+ */
+ max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
+
+ 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;
+ iph6 = skb->nh.ipv6h;
+ }
+
+ skb->h.raw = skb->nh.raw;
+ skb->nh.raw = skb_push(skb, sizeof(struct iphdr));
+ memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
+ dst_release(skb->dst);
+ skb->dst = &rt->u.dst;
+
+ /*
+ * Push down and install the IPIP header.
+ */
+
+ iph = skb->nh.iph;
+ iph->version = 4;
+ iph->ihl = sizeof(struct iphdr)>>2;
+ if (mtu > IPV6_MIN_MTU)
+ iph->frag_off = htons(IP_DF);
+ else
+ iph->frag_off = 0;
+
+ iph->protocol = IPPROTO_IPV6;
+ iph->tos = INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
+ iph->daddr = rt->rt_dst;
+ iph->saddr = rt->rt_src;
+
+ if ((iph->ttl = tiph->ttl) == 0)
+ iph->ttl = iph6->hop_limit;
+
+ 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
+ipip6_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 == ipip6_fb_tunnel_dev) {
+ if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
+ err = -EFAULT;
+ break;
+ }
+ t = ipip6_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_IPV6 ||
+ 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 = ipip6_tunnel_locate(&p, cmd == SIOCADDTUNNEL);
+
+ if (dev != ipip6_fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
+ if (t != NULL) {
+ if (t->dev != dev) {
+ err = -EEXIST;
+ break;
+ }
+ } else {
+ if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
+ (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
+ err = -EINVAL;
+ break;
+ }
+ t = (struct ip_tunnel*)dev->priv;
+ ipip6_tunnel_unlink(t);
+ t->parms.iph.saddr = p.iph.saddr;
+ t->parms.iph.daddr = p.iph.daddr;
+ memcpy(dev->dev_addr, &p.iph.saddr, 4);
+ memcpy(dev->broadcast, &p.iph.daddr, 4);
+ ipip6_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;
+ }
+ 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 == ipip6_fb_tunnel_dev) {
+ err = -EFAULT;
+ if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
+ goto done;
+ err = -ENOENT;
+ if ((t = ipip6_tunnel_locate(&p, 0)) == NULL)
+ goto done;
+ err = -EPERM;
+ if (t == ipip6_fb_tunnel_dev->priv)
+ goto done;
+ dev = t->dev;
+ }
+ err = unregister_netdevice(dev);
+ break;
+
+ default:
+ err = -EINVAL;
+ }
+
+done:
+ return err;
+}
+
+static struct net_device_stats *ipip6_tunnel_get_stats(struct net_device *dev)
+{
+ return &(((struct ip_tunnel*)dev->priv)->stat);
+}
+
+static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
+{
+ if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
+ return -EINVAL;
+ dev->mtu = new_mtu;
+ return 0;
+}
+
+static void ipip6_tunnel_setup(struct net_device *dev)
+{
+ SET_MODULE_OWNER(dev);
+ dev->uninit = ipip6_tunnel_uninit;
+ dev->destructor = free_netdev;
+ dev->hard_start_xmit = ipip6_tunnel_xmit;
+ dev->get_stats = ipip6_tunnel_get_stats;
+ dev->do_ioctl = ipip6_tunnel_ioctl;
+ dev->change_mtu = ipip6_tunnel_change_mtu;
+
+ dev->type = ARPHRD_SIT;
+ dev->hard_header_len = LL_MAX_HEADER + sizeof(struct iphdr);
+ dev->mtu = 1500 - sizeof(struct iphdr);
+ dev->flags = IFF_NOARP;
+ dev->iflink = 0;
+ dev->addr_len = 4;
+}
+
+static int ipip6_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);
+
+ memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
+ memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
+
+ if (iph->daddr) {
+ struct flowi fl = { .nl_u = { .ip4_u =
+ { .daddr = iph->daddr,
+ .saddr = iph->saddr,
+ .tos = RT_TOS(iph->tos) } },
+ .oif = tunnel->parms.link,
+ .proto = IPPROTO_IPV6 };
+ struct rtable *rt;
+ if (!ip_route_output_key(&rt, &fl)) {
+ tdev = rt->u.dst.dev;
+ ip_rt_put(rt);
+ }
+ dev->flags |= IFF_POINTOPOINT;
+ }
+
+ 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 iphdr);
+ dev->mtu = tdev->mtu - sizeof(struct iphdr);
+ if (dev->mtu < IPV6_MIN_MTU)
+ dev->mtu = IPV6_MIN_MTU;
+ }
+ dev->iflink = tunnel->parms.link;
+
+ return 0;
+}
+
+int __init ipip6_fb_tunnel_init(struct net_device *dev)
+{
+ struct ip_tunnel *tunnel = dev->priv;
+ struct iphdr *iph = &tunnel->parms.iph;
+
+ tunnel->dev = dev;
+ strcpy(tunnel->parms.name, dev->name);
+
+ iph->version = 4;
+ iph->protocol = IPPROTO_IPV6;
+ iph->ihl = 5;
+ iph->ttl = 64;
+
+ dev_hold(dev);
+ tunnels_wc[0] = tunnel;
+ return 0;
+}
+
+static struct net_protocol sit_protocol = {
+ .handler = ipip6_rcv,
+ .err_handler = ipip6_err,
+};
+
+void __exit sit_cleanup(void)
+{
+ inet_del_protocol(&sit_protocol, IPPROTO_IPV6);
+ unregister_netdev(ipip6_fb_tunnel_dev);
+}
+
+int __init sit_init(void)
+{
+ int err;
+
+ printk(KERN_INFO "IPv6 over IPv4 tunneling driver\n");
+
+ if (inet_add_protocol(&sit_protocol, IPPROTO_IPV6) < 0) {
+ printk(KERN_INFO "sit init: Can't add protocol\n");
+ return -EAGAIN;
+ }
+
+ ipip6_fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
+ ipip6_tunnel_setup);
+ if (!ipip6_fb_tunnel_dev) {
+ err = -ENOMEM;
+ goto err1;
+ }
+
+ ipip6_fb_tunnel_dev->init = ipip6_fb_tunnel_init;
+
+ if ((err = register_netdev(ipip6_fb_tunnel_dev)))
+ goto err2;
+
+ out:
+ return err;
+ err2:
+ free_netdev(ipip6_fb_tunnel_dev);
+ err1:
+ inet_del_protocol(&sit_protocol, IPPROTO_IPV6);
+ goto out;
+}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.