/* * IPv6 tunneling device * Linux INET6 implementation * * Authors: * Ville Nuorvala <vnuorval@tcs.hut.fi> * Yasuyuki Kozakai <kozakai@linux-ipv6.org> * * Based on: * linux/net/ipv6/sit.c and linux/net/ipv4/ipip.c * * RFC 2473 * * 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. * */ #include <linux/module.h> #include <linux/capability.h> #include <linux/errno.h> #include <linux/types.h> #include <linux/sockios.h> #include <linux/icmp.h> #include <linux/if.h> #include <linux/in.h> #include <linux/ip.h> #include <linux/if_tunnel.h> #include <linux/net.h> #include <linux/in6.h> #include <linux/netdevice.h> #include <linux/if_arp.h> #include <linux/icmpv6.h> #include <linux/init.h> #include <linux/route.h> #include <linux/rtnetlink.h> #include <linux/netfilter_ipv6.h> #include <linux/slab.h> #include <asm/uaccess.h> #include <linux/atomic.h> #include <net/icmp.h> #include <net/ip.h> #include <net/ipv6.h> #include <net/ip6_route.h> #include <net/addrconf.h> #include <net/ip6_tunnel.h> #include <net/xfrm.h> #include <net/dsfield.h> #include <net/inet_ecn.h> #include <net/net_namespace.h> #include <net/netns/generic.h> MODULE_AUTHOR("Ville Nuorvala"); MODULE_DESCRIPTION("IPv6 tunneling device"); MODULE_LICENSE("GPL"); MODULE_ALIAS_NETDEV("ip6tnl0"); #ifdef IP6_TNL_DEBUG #define IP6_TNL_TRACE(x...) printk(KERN_DEBUG "%s:" x "\n", __func__) #else #define IP6_TNL_TRACE(x...) do {;} while(0) #endif #define IPV6_TCLASS_MASK (IPV6_FLOWINFO_MASK & ~IPV6_FLOWLABEL_MASK) #define IPV6_TCLASS_SHIFT 20 #define HASH_SIZE 32 #define HASH(addr) ((__force u32)((addr)->s6_addr32[0] ^ (addr)->s6_addr32[1] ^ \ (addr)->s6_addr32[2] ^ (addr)->s6_addr32[3]) & \ (HASH_SIZE - 1)) static int ip6_tnl_dev_init(struct net_device *dev); static void ip6_tnl_dev_setup(struct net_device *dev); static int ip6_tnl_net_id __read_mostly; struct ip6_tnl_net { /* the IPv6 tunnel fallback device */ struct net_device *fb_tnl_dev; /* lists for storing tunnels in use */ struct ip6_tnl __rcu *tnls_r_l[HASH_SIZE]; struct ip6_tnl __rcu *tnls_wc[1]; struct ip6_tnl __rcu **tnls[2]; }; /* often modified stats are per cpu, other are shared (netdev->stats) */ struct pcpu_tstats { unsigned long rx_packets; unsigned long rx_bytes; unsigned long tx_packets; unsigned long tx_bytes; }; static struct net_device_stats *ip6_get_stats(struct net_device *dev) { struct pcpu_tstats sum = { 0 }; int i; for_each_possible_cpu(i) { const struct pcpu_tstats *tstats = per_cpu_ptr(dev->tstats, i); sum.rx_packets += tstats->rx_packets; sum.rx_bytes += tstats->rx_bytes; sum.tx_packets += tstats->tx_packets; sum.tx_bytes += tstats->tx_bytes; } dev->stats.rx_packets = sum.rx_packets; dev->stats.rx_bytes = sum.rx_bytes; dev->stats.tx_packets = sum.tx_packets; dev->stats.tx_bytes = sum.tx_bytes; return &dev->stats; } /* * Locking : hash tables are protected by RCU and RTNL */ static inline struct dst_entry *ip6_tnl_dst_check(struct ip6_tnl *t) { struct dst_entry *dst = t->dst_cache; if (dst && dst->obsolete && dst->ops->check(dst, t->dst_cookie) == NULL) { t->dst_cache = NULL; dst_release(dst); return NULL; } return dst; } static inline void ip6_tnl_dst_reset(struct ip6_tnl *t) { dst_release(t->dst_cache); t->dst_cache = NULL; } static inline void ip6_tnl_dst_store(struct ip6_tnl *t, struct dst_entry *dst) { struct rt6_info *rt = (struct rt6_info *) dst; t->dst_cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0; dst_release(t->dst_cache); t->dst_cache = dst; } /** * ip6_tnl_lookup - fetch tunnel matching the end-point addresses * @remote: the address of the tunnel exit-point * @local: the address of the tunnel entry-point * * Return: * tunnel matching given end-points if found, * else fallback tunnel if its device is up, * else %NULL **/ #define for_each_ip6_tunnel_rcu(start) \ for (t = rcu_dereference(start); t; t = rcu_dereference(t->next)) static struct ip6_tnl * ip6_tnl_lookup(struct net *net, const struct in6_addr *remote, const struct in6_addr *local) { unsigned int h0 = HASH(remote); unsigned int h1 = HASH(local); struct ip6_tnl *t; struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id); for_each_ip6_tunnel_rcu(ip6n->tnls_r_l[h0 ^ h1]) { if (ipv6_addr_equal(local, &t->parms.laddr) && ipv6_addr_equal(remote, &t->parms.raddr) && (t->dev->flags & IFF_UP)) return t; } t = rcu_dereference(ip6n->tnls_wc[0]); if (t && (t->dev->flags & IFF_UP)) return t; return NULL; } /** * ip6_tnl_bucket - get head of list matching given tunnel parameters * @p: parameters containing tunnel end-points * * Description: * ip6_tnl_bucket() returns the head of the list matching the * &struct in6_addr entries laddr and raddr in @p. * * Return: head of IPv6 tunnel list **/ static struct ip6_tnl __rcu ** ip6_tnl_bucket(struct ip6_tnl_net *ip6n, const struct ip6_tnl_parm *p) { const struct in6_addr *remote = &p->raddr; const struct in6_addr *local = &p->laddr; unsigned h = 0; int prio = 0; if (!ipv6_addr_any(remote) || !ipv6_addr_any(local)) { prio = 1; h = HASH(remote) ^ HASH(local); } return &ip6n->tnls[prio][h]; } /** * ip6_tnl_link - add tunnel to hash table * @t: tunnel to be added **/ static void ip6_tnl_link(struct ip6_tnl_net *ip6n, struct ip6_tnl *t) { struct ip6_tnl __rcu **tp = ip6_tnl_bucket(ip6n, &t->parms); RCU_INIT_POINTER(t->next , rtnl_dereference(*tp)); RCU_INIT_POINTER(*tp, t); } /** * ip6_tnl_unlink - remove tunnel from hash table * @t: tunnel to be removed **/ static void ip6_tnl_unlink(struct ip6_tnl_net *ip6n, struct ip6_tnl *t) { struct ip6_tnl __rcu **tp; struct ip6_tnl *iter; for (tp = ip6_tnl_bucket(ip6n, &t->parms); (iter = rtnl_dereference(*tp)) != NULL; tp = &iter->next) { if (t == iter) { RCU_INIT_POINTER(*tp, t->next); break; } } } static void ip6_dev_free(struct net_device *dev) { free_percpu(dev->tstats); free_netdev(dev); } /** * ip6_tnl_create() - create a new tunnel * @p: tunnel parameters * @pt: pointer to new tunnel * * Description: * Create tunnel matching given parameters. * * Return: * created tunnel or NULL **/ static struct ip6_tnl *ip6_tnl_create(struct net *net, struct ip6_tnl_parm *p) { struct net_device *dev; struct ip6_tnl *t; char name[IFNAMSIZ]; int err; struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id); if (p->name[0]) strlcpy(name, p->name, IFNAMSIZ); else sprintf(name, "ip6tnl%%d"); dev = alloc_netdev(sizeof (*t), name, ip6_tnl_dev_setup); if (dev == NULL) goto failed; dev_net_set(dev, net); t = netdev_priv(dev); t->parms = *p; err = ip6_tnl_dev_init(dev); if (err < 0) goto failed_free; if ((err = register_netdevice(dev)) < 0) goto failed_free; dev_hold(dev); ip6_tnl_link(ip6n, t); return t; failed_free: ip6_dev_free(dev); failed: return NULL; } /** * ip6_tnl_locate - find or create tunnel matching given parameters * @p: tunnel parameters * @create: != 0 if allowed to create new tunnel if no match found * * Description: * ip6_tnl_locate() first tries to locate an existing tunnel * based on @parms. If this is unsuccessful, but @create is set a new * tunnel device is created and registered for use. * * Return: * matching tunnel or NULL **/ static struct ip6_tnl *ip6_tnl_locate(struct net *net, struct ip6_tnl_parm *p, int create) { const struct in6_addr *remote = &p->raddr; const struct in6_addr *local = &p->laddr; struct ip6_tnl __rcu **tp; struct ip6_tnl *t; struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id); for (tp = ip6_tnl_bucket(ip6n, p); (t = rtnl_dereference(*tp)) != NULL; tp = &t->next) { if (ipv6_addr_equal(local, &t->parms.laddr) && ipv6_addr_equal(remote, &t->parms.raddr)) return t; } if (!create) return NULL; return ip6_tnl_create(net, p); } /** * ip6_tnl_dev_uninit - tunnel device uninitializer * @dev: the device to be destroyed * * Description: * ip6_tnl_dev_uninit() removes tunnel from its list **/ static void ip6_tnl_dev_uninit(struct net_device *dev) { struct ip6_tnl *t = netdev_priv(dev); struct net *net = dev_net(dev); struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id); if (dev == ip6n->fb_tnl_dev) RCU_INIT_POINTER(ip6n->tnls_wc[0], NULL); else ip6_tnl_unlink(ip6n, t); ip6_tnl_dst_reset(t); dev_put(dev); } /** * parse_tvl_tnl_enc_lim - handle encapsulation limit option * @skb: received socket buffer * * Return: * 0 if none was found, * else index to encapsulation limit **/ static __u16 parse_tlv_tnl_enc_lim(struct sk_buff *skb, __u8 * raw) { const struct ipv6hdr *ipv6h = (const struct ipv6hdr *) raw; __u8 nexthdr = ipv6h->nexthdr; __u16 off = sizeof (*ipv6h); while (ipv6_ext_hdr(nexthdr) && nexthdr != NEXTHDR_NONE) { __u16 optlen = 0; struct ipv6_opt_hdr *hdr; if (raw + off + sizeof (*hdr) > skb->data && !pskb_may_pull(skb, raw - skb->data + off + sizeof (*hdr))) break; hdr = (struct ipv6_opt_hdr *) (raw + off); if (nexthdr == NEXTHDR_FRAGMENT) { struct frag_hdr *frag_hdr = (struct frag_hdr *) hdr; if (frag_hdr->frag_off) break; optlen = 8; } else if (nexthdr == NEXTHDR_AUTH) { optlen = (hdr->hdrlen + 2) << 2; } else { optlen = ipv6_optlen(hdr); } if (nexthdr == NEXTHDR_DEST) { __u16 i = off + 2; while (1) { struct ipv6_tlv_tnl_enc_lim *tel; /* No more room for encapsulation limit */ if (i + sizeof (*tel) > off + optlen) break; tel = (struct ipv6_tlv_tnl_enc_lim *) &raw[i]; /* return index of option if found and valid */ if (tel->type == IPV6_TLV_TNL_ENCAP_LIMIT && tel->length == 1) return i; /* else jump to next option */ if (tel->type) i += tel->length + 2; else i++; } } nexthdr = hdr->nexthdr; off += optlen; } return 0; } /** * ip6_tnl_err - tunnel error handler * * Description: * ip6_tnl_err() should handle errors in the tunnel according * to the specifications in RFC 2473. **/ static int ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt, u8 *type, u8 *code, int *msg, __u32 *info, int offset) { const struct ipv6hdr *ipv6h = (const struct ipv6hdr *) skb->data; struct ip6_tnl *t; int rel_msg = 0; u8 rel_type = ICMPV6_DEST_UNREACH; u8 rel_code = ICMPV6_ADDR_UNREACH; __u32 rel_info = 0; __u16 len; int err = -ENOENT; /* If the packet doesn't contain the original IPv6 header we are in trouble since we might need the source address for further processing of the error. */ rcu_read_lock(); if ((t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->daddr, &ipv6h->saddr)) == NULL) goto out; if (t->parms.proto != ipproto && t->parms.proto != 0) goto out; err = 0; switch (*type) { __u32 teli; struct ipv6_tlv_tnl_enc_lim *tel; __u32 mtu; case ICMPV6_DEST_UNREACH: if (net_ratelimit()) printk(KERN_WARNING "%s: Path to destination invalid " "or inactive!\n", t->parms.name); rel_msg = 1; break; case ICMPV6_TIME_EXCEED: if ((*code) == ICMPV6_EXC_HOPLIMIT) { if (net_ratelimit()) printk(KERN_WARNING "%s: Too small hop limit or " "routing loop in tunnel!\n", t->parms.name); rel_msg = 1; } break; case ICMPV6_PARAMPROB: teli = 0; if ((*code) == ICMPV6_HDR_FIELD) teli = parse_tlv_tnl_enc_lim(skb, skb->data); if (teli && teli == *info - 2) { tel = (struct ipv6_tlv_tnl_enc_lim *) &skb->data[teli]; if (tel->encap_limit == 0) { if (net_ratelimit()) printk(KERN_WARNING "%s: Too small encapsulation " "limit or routing loop in " "tunnel!\n", t->parms.name); rel_msg = 1; } } else if (net_ratelimit()) { printk(KERN_WARNING "%s: Recipient unable to parse tunneled " "packet!\n ", t->parms.name); } break; case ICMPV6_PKT_TOOBIG: mtu = *info - offset; if (mtu < IPV6_MIN_MTU) mtu = IPV6_MIN_MTU; t->dev->mtu = mtu; if ((len = sizeof (*ipv6h) + ntohs(ipv6h->payload_len)) > mtu) { rel_type = ICMPV6_PKT_TOOBIG; rel_code = 0; rel_info = mtu; rel_msg = 1; } break; } *type = rel_type; *code = rel_code; *info = rel_info; *msg = rel_msg; out: rcu_read_unlock(); return err; } static int ip4ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, u8 type, u8 code, int offset, __be32 info) { int rel_msg = 0; u8 rel_type = type; u8 rel_code = code; __u32 rel_info = ntohl(info); int err; struct sk_buff *skb2; const struct iphdr *eiph; struct rtable *rt; struct flowi4 fl4; err = ip6_tnl_err(skb, IPPROTO_IPIP, opt, &rel_type, &rel_code, &rel_msg, &rel_info, offset); if (err < 0) return err; if (rel_msg == 0) return 0; switch (rel_type) { case ICMPV6_DEST_UNREACH: if (rel_code != ICMPV6_ADDR_UNREACH) return 0; rel_type = ICMP_DEST_UNREACH; rel_code = ICMP_HOST_UNREACH; break; case ICMPV6_PKT_TOOBIG: if (rel_code != 0) return 0; rel_type = ICMP_DEST_UNREACH; rel_code = ICMP_FRAG_NEEDED; break; default: return 0; } if (!pskb_may_pull(skb, offset + sizeof(struct iphdr))) return 0; skb2 = skb_clone(skb, GFP_ATOMIC); if (!skb2) return 0; skb_dst_drop(skb2); skb_pull(skb2, offset); skb_reset_network_header(skb2); eiph = ip_hdr(skb2); /* Try to guess incoming interface */ rt = ip_route_output_ports(dev_net(skb->dev), &fl4, NULL, eiph->saddr, 0, 0, 0, IPPROTO_IPIP, RT_TOS(eiph->tos), 0); if (IS_ERR(rt)) goto out; skb2->dev = rt->dst.dev; /* route "incoming" packet */ if (rt->rt_flags & RTCF_LOCAL) { ip_rt_put(rt); rt = NULL; rt = ip_route_output_ports(dev_net(skb->dev), &fl4, NULL, eiph->daddr, eiph->saddr, 0, 0, IPPROTO_IPIP, RT_TOS(eiph->tos), 0); if (IS_ERR(rt) || rt->dst.dev->type != ARPHRD_TUNNEL) { if (!IS_ERR(rt)) ip_rt_put(rt); goto out; } skb_dst_set(skb2, &rt->dst); } else { ip_rt_put(rt); if (ip_route_input(skb2, eiph->daddr, eiph->saddr, eiph->tos, skb2->dev) || skb_dst(skb2)->dev->type != ARPHRD_TUNNEL) goto out; } /* change mtu on this route */ if (rel_type == ICMP_DEST_UNREACH && rel_code == ICMP_FRAG_NEEDED) { if (rel_info > dst_mtu(skb_dst(skb2))) goto out; skb_dst(skb2)->ops->update_pmtu(skb_dst(skb2), rel_info); } icmp_send(skb2, rel_type, rel_code, htonl(rel_info)); out: kfree_skb(skb2); return 0; } static int ip6ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, u8 type, u8 code, int offset, __be32 info) { int rel_msg = 0; u8 rel_type = type; u8 rel_code = code; __u32 rel_info = ntohl(info); int err; err = ip6_tnl_err(skb, IPPROTO_IPV6, opt, &rel_type, &rel_code, &rel_msg, &rel_info, offset); if (err < 0) return err; if (rel_msg && pskb_may_pull(skb, offset + sizeof(struct ipv6hdr))) { struct rt6_info *rt; struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC); if (!skb2) return 0; skb_dst_drop(skb2); skb_pull(skb2, offset); skb_reset_network_header(skb2); /* Try to guess incoming interface */ rt = rt6_lookup(dev_net(skb->dev), &ipv6_hdr(skb2)->saddr, NULL, 0, 0); if (rt && rt->rt6i_dev) skb2->dev = rt->rt6i_dev; icmpv6_send(skb2, rel_type, rel_code, rel_info); if (rt) dst_release(&rt->dst); kfree_skb(skb2); } return 0; } static void ip4ip6_dscp_ecn_decapsulate(const struct ip6_tnl *t, const struct ipv6hdr *ipv6h, struct sk_buff *skb) { __u8 dsfield = ipv6_get_dsfield(ipv6h) & ~INET_ECN_MASK; if (t->parms.flags & IP6_TNL_F_RCV_DSCP_COPY) ipv4_change_dsfield(ip_hdr(skb), INET_ECN_MASK, dsfield); if (INET_ECN_is_ce(dsfield)) IP_ECN_set_ce(ip_hdr(skb)); } static void ip6ip6_dscp_ecn_decapsulate(const struct ip6_tnl *t, const struct ipv6hdr *ipv6h, struct sk_buff *skb) { if (t->parms.flags & IP6_TNL_F_RCV_DSCP_COPY) ipv6_copy_dscp(ipv6_get_dsfield(ipv6h), ipv6_hdr(skb)); if (INET_ECN_is_ce(ipv6_get_dsfield(ipv6h))) IP6_ECN_set_ce(ipv6_hdr(skb)); } /* called with rcu_read_lock() */ static inline int ip6_tnl_rcv_ctl(struct ip6_tnl *t) { struct ip6_tnl_parm *p = &t->parms; int ret = 0; struct net *net = dev_net(t->dev); if (p->flags & IP6_TNL_F_CAP_RCV) { struct net_device *ldev = NULL; if (p->link) ldev = dev_get_by_index_rcu(net, p->link); if ((ipv6_addr_is_multicast(&p->laddr) || likely(ipv6_chk_addr(net, &p->laddr, ldev, 0))) && likely(!ipv6_chk_addr(net, &p->raddr, NULL, 0))) ret = 1; } return ret; } /** * ip6_tnl_rcv - decapsulate IPv6 packet and retransmit it locally * @skb: received socket buffer * @protocol: ethernet protocol ID * @dscp_ecn_decapsulate: the function to decapsulate DSCP code and ECN * * Return: 0 **/ static int ip6_tnl_rcv(struct sk_buff *skb, __u16 protocol, __u8 ipproto, void (*dscp_ecn_decapsulate)(const struct ip6_tnl *t, const struct ipv6hdr *ipv6h, struct sk_buff *skb)) { struct ip6_tnl *t; const struct ipv6hdr *ipv6h = ipv6_hdr(skb); rcu_read_lock(); if ((t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->saddr, &ipv6h->daddr)) != NULL) { struct pcpu_tstats *tstats; if (t->parms.proto != ipproto && t->parms.proto != 0) { rcu_read_unlock(); goto discard; } if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { rcu_read_unlock(); goto discard; } if (!ip6_tnl_rcv_ctl(t)) { t->dev->stats.rx_dropped++; rcu_read_unlock(); goto discard; } secpath_reset(skb); skb->mac_header = skb->network_header; skb_reset_network_header(skb); skb->protocol = htons(protocol); skb->pkt_type = PACKET_HOST; memset(skb->cb, 0, sizeof(struct inet6_skb_parm)); tstats = this_cpu_ptr(t->dev->tstats); tstats->rx_packets++; tstats->rx_bytes += skb->len; __skb_tunnel_rx(skb, t->dev); dscp_ecn_decapsulate(t, ipv6h, skb); netif_rx(skb); rcu_read_unlock(); return 0; } rcu_read_unlock(); return 1; discard: kfree_skb(skb); return 0; } static int ip4ip6_rcv(struct sk_buff *skb) { return ip6_tnl_rcv(skb, ETH_P_IP, IPPROTO_IPIP, ip4ip6_dscp_ecn_decapsulate); } static int ip6ip6_rcv(struct sk_buff *skb) { return ip6_tnl_rcv(skb, ETH_P_IPV6, IPPROTO_IPV6, ip6ip6_dscp_ecn_decapsulate); } struct ipv6_tel_txoption { struct ipv6_txoptions ops; __u8 dst_opt[8]; }; static void init_tel_txopt(struct ipv6_tel_txoption *opt, __u8 encap_limit) { memset(opt, 0, sizeof(struct ipv6_tel_txoption)); opt->dst_opt[2] = IPV6_TLV_TNL_ENCAP_LIMIT; opt->dst_opt[3] = 1; opt->dst_opt[4] = encap_limit; opt->dst_opt[5] = IPV6_TLV_PADN; opt->dst_opt[6] = 1; opt->ops.dst0opt = (struct ipv6_opt_hdr *) opt->dst_opt; opt->ops.opt_nflen = 8; } /** * ip6_tnl_addr_conflict - compare packet addresses to tunnel's own * @t: the outgoing tunnel device * @hdr: IPv6 header from the incoming packet * * Description: * Avoid trivial tunneling loop by checking that tunnel exit-point * doesn't match source of incoming packet. * * Return: * 1 if conflict, * 0 else **/ static inline int ip6_tnl_addr_conflict(const struct ip6_tnl *t, const struct ipv6hdr *hdr) { return ipv6_addr_equal(&t->parms.raddr, &hdr->saddr); } static inline int ip6_tnl_xmit_ctl(struct ip6_tnl *t) { struct ip6_tnl_parm *p = &t->parms; int ret = 0; struct net *net = dev_net(t->dev); if (p->flags & IP6_TNL_F_CAP_XMIT) { struct net_device *ldev = NULL; rcu_read_lock(); if (p->link) ldev = dev_get_by_index_rcu(net, p->link); if (unlikely(!ipv6_chk_addr(net, &p->laddr, ldev, 0))) printk(KERN_WARNING "%s xmit: Local address not yet configured!\n", p->name); else if (!ipv6_addr_is_multicast(&p->raddr) && unlikely(ipv6_chk_addr(net, &p->raddr, NULL, 0))) printk(KERN_WARNING "%s xmit: Routing loop! " "Remote address found on this node!\n", p->name); else ret = 1; rcu_read_unlock(); } return ret; } /** * ip6_tnl_xmit2 - encapsulate packet and send * @skb: the outgoing socket buffer * @dev: the outgoing tunnel device * @dsfield: dscp code for outer header * @fl: flow of tunneled packet * @encap_limit: encapsulation limit * @pmtu: Path MTU is stored if packet is too big * * Description: * Build new header and do some sanity checks on the packet before sending * it. * * Return: * 0 on success * -1 fail * %-EMSGSIZE message too big. return mtu in this case. **/ static int ip6_tnl_xmit2(struct sk_buff *skb, struct net_device *dev, __u8 dsfield, struct flowi6 *fl6, int encap_limit, __u32 *pmtu) { struct net *net = dev_net(dev); struct ip6_tnl *t = netdev_priv(dev); struct net_device_stats *stats = &t->dev->stats; struct ipv6hdr *ipv6h = ipv6_hdr(skb); struct ipv6_tel_txoption opt; struct dst_entry *dst = NULL, *ndst = NULL; struct net_device *tdev; int mtu; unsigned int max_headroom = sizeof(struct ipv6hdr); u8 proto; int err = -1; int pkt_len; if (!fl6->flowi6_mark) dst = ip6_tnl_dst_check(t); if (!dst) { ndst = ip6_route_output(net, NULL, fl6); if (ndst->error) goto tx_err_link_failure; ndst = xfrm_lookup(net, ndst, flowi6_to_flowi(fl6), NULL, 0); if (IS_ERR(ndst)) { err = PTR_ERR(ndst); ndst = NULL; goto tx_err_link_failure; } dst = ndst; } tdev = dst->dev; if (tdev == dev) { stats->collisions++; if (net_ratelimit()) printk(KERN_WARNING "%s: Local routing loop detected!\n", t->parms.name); goto tx_err_dst_release; } mtu = dst_mtu(dst) - sizeof (*ipv6h); if (encap_limit >= 0) { max_headroom += 8; mtu -= 8; } if (mtu < IPV6_MIN_MTU) mtu = IPV6_MIN_MTU; if (skb_dst(skb)) skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu); if (skb->len > mtu) { *pmtu = mtu; err = -EMSGSIZE; goto tx_err_dst_release; } /* * Okay, now see if we can stuff it in the buffer as-is. */ max_headroom += LL_RESERVED_SPACE(tdev); if (skb_headroom(skb) < max_headroom || skb_shared(skb) || (skb_cloned(skb) && !skb_clone_writable(skb, 0))) { struct sk_buff *new_skb; if (!(new_skb = skb_realloc_headroom(skb, max_headroom))) goto tx_err_dst_release; if (skb->sk) skb_set_owner_w(new_skb, skb->sk); kfree_skb(skb); skb = new_skb; } skb_dst_drop(skb); if (fl6->flowi6_mark) { skb_dst_set(skb, dst); ndst = NULL; } else { skb_dst_set_noref(skb, dst); } skb->transport_header = skb->network_header; proto = fl6->flowi6_proto; if (encap_limit >= 0) { init_tel_txopt(&opt, encap_limit); ipv6_push_nfrag_opts(skb, &opt.ops, &proto, NULL); } skb_push(skb, sizeof(struct ipv6hdr)); skb_reset_network_header(skb); ipv6h = ipv6_hdr(skb); *(__be32*)ipv6h = fl6->flowlabel | htonl(0x60000000); dsfield = INET_ECN_encapsulate(0, dsfield); ipv6_change_dsfield(ipv6h, ~INET_ECN_MASK, dsfield); ipv6h->hop_limit = t->parms.hop_limit; ipv6h->nexthdr = proto; ipv6_addr_copy(&ipv6h->saddr, &fl6->saddr); ipv6_addr_copy(&ipv6h->daddr, &fl6->daddr); nf_reset(skb); pkt_len = skb->len; err = ip6_local_out(skb); if (net_xmit_eval(err) == 0) { struct pcpu_tstats *tstats = this_cpu_ptr(t->dev->tstats); tstats->tx_bytes += pkt_len; tstats->tx_packets++; } else { stats->tx_errors++; stats->tx_aborted_errors++; } if (ndst) ip6_tnl_dst_store(t, ndst); return 0; tx_err_link_failure: stats->tx_carrier_errors++; dst_link_failure(skb); tx_err_dst_release: dst_release(ndst); return err; } static inline int ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) { struct ip6_tnl *t = netdev_priv(dev); const struct iphdr *iph = ip_hdr(skb); int encap_limit = -1; struct flowi6 fl6; __u8 dsfield; __u32 mtu; int err; if ((t->parms.proto != IPPROTO_IPIP && t->parms.proto != 0) || !ip6_tnl_xmit_ctl(t)) return -1; if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT)) encap_limit = t->parms.encap_limit; memcpy(&fl6, &t->fl.u.ip6, sizeof (fl6)); fl6.flowi6_proto = IPPROTO_IPIP; dsfield = ipv4_get_dsfield(iph); if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS) fl6.flowlabel |= htonl((__u32)iph->tos << IPV6_TCLASS_SHIFT) & IPV6_TCLASS_MASK; if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK) fl6.flowi6_mark = skb->mark; err = ip6_tnl_xmit2(skb, dev, dsfield, &fl6, encap_limit, &mtu); if (err != 0) { /* XXX: send ICMP error even if DF is not set. */ if (err == -EMSGSIZE) icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu)); return -1; } return 0; } static inline int ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) { struct ip6_tnl *t = netdev_priv(dev); struct ipv6hdr *ipv6h = ipv6_hdr(skb); int encap_limit = -1; __u16 offset; struct flowi6 fl6; __u8 dsfield; __u32 mtu; int err; if ((t->parms.proto != IPPROTO_IPV6 && t->parms.proto != 0) || !ip6_tnl_xmit_ctl(t) || ip6_tnl_addr_conflict(t, ipv6h)) return -1; offset = parse_tlv_tnl_enc_lim(skb, skb_network_header(skb)); if (offset > 0) { struct ipv6_tlv_tnl_enc_lim *tel; tel = (struct ipv6_tlv_tnl_enc_lim *)&skb_network_header(skb)[offset]; if (tel->encap_limit == 0) { icmpv6_send(skb, ICMPV6_PARAMPROB, ICMPV6_HDR_FIELD, offset + 2); return -1; } encap_limit = tel->encap_limit - 1; } else if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT)) encap_limit = t->parms.encap_limit; memcpy(&fl6, &t->fl.u.ip6, sizeof (fl6)); fl6.flowi6_proto = IPPROTO_IPV6; dsfield = ipv6_get_dsfield(ipv6h); if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS) fl6.flowlabel |= (*(__be32 *) ipv6h & IPV6_TCLASS_MASK); if (t->parms.flags & IP6_TNL_F_USE_ORIG_FLOWLABEL) fl6.flowlabel |= (*(__be32 *) ipv6h & IPV6_FLOWLABEL_MASK); if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK) fl6.flowi6_mark = skb->mark; err = ip6_tnl_xmit2(skb, dev, dsfield, &fl6, encap_limit, &mtu); if (err != 0) { if (err == -EMSGSIZE) icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); return -1; } return 0; } static netdev_tx_t ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) { struct ip6_tnl *t = netdev_priv(dev); struct net_device_stats *stats = &t->dev->stats; int ret; switch (skb->protocol) { case htons(ETH_P_IP): ret = ip4ip6_tnl_xmit(skb, dev); break; case htons(ETH_P_IPV6): ret = ip6ip6_tnl_xmit(skb, dev); break; default: goto tx_err; } if (ret < 0) goto tx_err; return NETDEV_TX_OK; tx_err: stats->tx_errors++; stats->tx_dropped++; kfree_skb(skb); return NETDEV_TX_OK; } static void ip6_tnl_set_cap(struct ip6_tnl *t) { struct ip6_tnl_parm *p = &t->parms; int ltype = ipv6_addr_type(&p->laddr); int rtype = ipv6_addr_type(&p->raddr); p->flags &= ~(IP6_TNL_F_CAP_XMIT|IP6_TNL_F_CAP_RCV); if (ltype & (IPV6_ADDR_UNICAST|IPV6_ADDR_MULTICAST) && rtype & (IPV6_ADDR_UNICAST|IPV6_ADDR_MULTICAST) && !((ltype|rtype) & IPV6_ADDR_LOOPBACK) && (!((ltype|rtype) & IPV6_ADDR_LINKLOCAL) || p->link)) { if (ltype&IPV6_ADDR_UNICAST) p->flags |= IP6_TNL_F_CAP_XMIT; if (rtype&IPV6_ADDR_UNICAST) p->flags |= IP6_TNL_F_CAP_RCV; } } static void ip6_tnl_link_config(struct ip6_tnl *t) { struct net_device *dev = t->dev; struct ip6_tnl_parm *p = &t->parms; struct flowi6 *fl6 = &t->fl.u.ip6; memcpy(dev->dev_addr, &p->laddr, sizeof(struct in6_addr)); memcpy(dev->broadcast, &p->raddr, sizeof(struct in6_addr)); /* Set up flowi template */ ipv6_addr_copy(&fl6->saddr, &p->laddr); ipv6_addr_copy(&fl6->daddr, &p->raddr); fl6->flowi6_oif = p->link; fl6->flowlabel = 0; if (!(p->flags&IP6_TNL_F_USE_ORIG_TCLASS)) fl6->flowlabel |= IPV6_TCLASS_MASK & p->flowinfo; if (!(p->flags&IP6_TNL_F_USE_ORIG_FLOWLABEL)) fl6->flowlabel |= IPV6_FLOWLABEL_MASK & p->flowinfo; ip6_tnl_set_cap(t); if (p->flags&IP6_TNL_F_CAP_XMIT && p->flags&IP6_TNL_F_CAP_RCV) dev->flags |= IFF_POINTOPOINT; else dev->flags &= ~IFF_POINTOPOINT; dev->iflink = p->link; if (p->flags & IP6_TNL_F_CAP_XMIT) { int strict = (ipv6_addr_type(&p->raddr) & (IPV6_ADDR_MULTICAST|IPV6_ADDR_LINKLOCAL)); struct rt6_info *rt = rt6_lookup(dev_net(dev), &p->raddr, &p->laddr, p->link, strict); if (rt == NULL) return; if (rt->rt6i_dev) { dev->hard_header_len = rt->rt6i_dev->hard_header_len + sizeof (struct ipv6hdr); dev->mtu = rt->rt6i_dev->mtu - sizeof (struct ipv6hdr); if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT)) dev->mtu-=8; if (dev->mtu < IPV6_MIN_MTU) dev->mtu = IPV6_MIN_MTU; } dst_release(&rt->dst); } } /** * ip6_tnl_change - update the tunnel parameters * @t: tunnel to be changed * @p: tunnel configuration parameters * * Description: * ip6_tnl_change() updates the tunnel parameters **/ static int ip6_tnl_change(struct ip6_tnl *t, struct ip6_tnl_parm *p) { ipv6_addr_copy(&t->parms.laddr, &p->laddr); ipv6_addr_copy(&t->parms.raddr, &p->raddr); t->parms.flags = p->flags; t->parms.hop_limit = p->hop_limit; t->parms.encap_limit = p->encap_limit; t->parms.flowinfo = p->flowinfo; t->parms.link = p->link; t->parms.proto = p->proto; ip6_tnl_dst_reset(t); ip6_tnl_link_config(t); return 0; } /** * ip6_tnl_ioctl - configure ipv6 tunnels from userspace * @dev: virtual device associated with tunnel * @ifr: parameters passed from userspace * @cmd: command to be performed * * Description: * ip6_tnl_ioctl() is used for managing IPv6 tunnels * from userspace. * * The possible commands are the following: * %SIOCGETTUNNEL: get tunnel parameters for device * %SIOCADDTUNNEL: add tunnel matching given tunnel parameters * %SIOCCHGTUNNEL: change tunnel parameters to those given * %SIOCDELTUNNEL: delete tunnel * * The fallback device "ip6tnl0", created during module * initialization, can be used for creating other tunnel devices. * * Return: * 0 on success, * %-EFAULT if unable to copy data to or from userspace, * %-EPERM if current process hasn't %CAP_NET_ADMIN set * %-EINVAL if passed tunnel parameters are invalid, * %-EEXIST if changing a tunnel's parameters would cause a conflict * %-ENODEV if attempting to change or delete a nonexisting device **/ static int ip6_tnl_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) { int err = 0; struct ip6_tnl_parm p; struct ip6_tnl *t = NULL; struct net *net = dev_net(dev); struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id); switch (cmd) { case SIOCGETTUNNEL: if (dev == ip6n->fb_tnl_dev) { if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof (p))) { err = -EFAULT; break; } t = ip6_tnl_locate(net, &p, 0); } if (t == NULL) t = netdev_priv(dev); 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)) break; err = -EFAULT; if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof (p))) break; err = -EINVAL; if (p.proto != IPPROTO_IPV6 && p.proto != IPPROTO_IPIP && p.proto != 0) break; t = ip6_tnl_locate(net, &p, cmd == SIOCADDTUNNEL); if (dev != ip6n->fb_tnl_dev && cmd == SIOCCHGTUNNEL) { if (t != NULL) { if (t->dev != dev) { err = -EEXIST; break; } } else t = netdev_priv(dev); ip6_tnl_unlink(ip6n, t); synchronize_net(); err = ip6_tnl_change(t, &p); ip6_tnl_link(ip6n, t); netdev_state_change(dev); } if (t) { err = 0; 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)) break; if (dev == ip6n->fb_tnl_dev) { err = -EFAULT; if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof (p))) break; err = -ENOENT; if ((t = ip6_tnl_locate(net, &p, 0)) == NULL) break; err = -EPERM; if (t->dev == ip6n->fb_tnl_dev) break; dev = t->dev; } err = 0; unregister_netdevice(dev); break; default: err = -EINVAL; } return err; } /** * ip6_tnl_change_mtu - change mtu manually for tunnel device * @dev: virtual device associated with tunnel * @new_mtu: the new mtu * * Return: * 0 on success, * %-EINVAL if mtu too small **/ static int ip6_tnl_change_mtu(struct net_device *dev, int new_mtu) { if (new_mtu < IPV6_MIN_MTU) { return -EINVAL; } dev->mtu = new_mtu; return 0; } static const struct net_device_ops ip6_tnl_netdev_ops = { .ndo_uninit = ip6_tnl_dev_uninit, .ndo_start_xmit = ip6_tnl_xmit, .ndo_do_ioctl = ip6_tnl_ioctl, .ndo_change_mtu = ip6_tnl_change_mtu, .ndo_get_stats = ip6_get_stats, }; /** * ip6_tnl_dev_setup - setup virtual tunnel device * @dev: virtual device associated with tunnel * * Description: * Initialize function pointers and device parameters **/ static void ip6_tnl_dev_setup(struct net_device *dev) { struct ip6_tnl *t; dev->netdev_ops = &ip6_tnl_netdev_ops; dev->destructor = ip6_dev_free; dev->type = ARPHRD_TUNNEL6; dev->hard_header_len = LL_MAX_HEADER + sizeof (struct ipv6hdr); dev->mtu = ETH_DATA_LEN - sizeof (struct ipv6hdr); t = netdev_priv(dev); if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT)) dev->mtu-=8; dev->flags |= IFF_NOARP; dev->addr_len = sizeof(struct in6_addr); dev->features |= NETIF_F_NETNS_LOCAL; dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; } /** * ip6_tnl_dev_init_gen - general initializer for all tunnel devices * @dev: virtual device associated with tunnel **/ static inline int ip6_tnl_dev_init_gen(struct net_device *dev) { struct ip6_tnl *t = netdev_priv(dev); t->dev = dev; strcpy(t->parms.name, dev->name); dev->tstats = alloc_percpu(struct pcpu_tstats); if (!dev->tstats) return -ENOMEM; return 0; } /** * ip6_tnl_dev_init - initializer for all non fallback tunnel devices * @dev: virtual device associated with tunnel **/ static int ip6_tnl_dev_init(struct net_device *dev) { struct ip6_tnl *t = netdev_priv(dev); int err = ip6_tnl_dev_init_gen(dev); if (err) return err; ip6_tnl_link_config(t); return 0; } /** * ip6_fb_tnl_dev_init - initializer for fallback tunnel device * @dev: fallback device * * Return: 0 **/ static int __net_init ip6_fb_tnl_dev_init(struct net_device *dev) { struct ip6_tnl *t = netdev_priv(dev); struct net *net = dev_net(dev); struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id); int err = ip6_tnl_dev_init_gen(dev); if (err) return err; t->parms.proto = IPPROTO_IPV6; dev_hold(dev); RCU_INIT_POINTER(ip6n->tnls_wc[0], t); return 0; } static struct xfrm6_tunnel ip4ip6_handler __read_mostly = { .handler = ip4ip6_rcv, .err_handler = ip4ip6_err, .priority = 1, }; static struct xfrm6_tunnel ip6ip6_handler __read_mostly = { .handler = ip6ip6_rcv, .err_handler = ip6ip6_err, .priority = 1, }; static void __net_exit ip6_tnl_destroy_tunnels(struct ip6_tnl_net *ip6n) { int h; struct ip6_tnl *t; LIST_HEAD(list); for (h = 0; h < HASH_SIZE; h++) { t = rtnl_dereference(ip6n->tnls_r_l[h]); while (t != NULL) { unregister_netdevice_queue(t->dev, &list); t = rtnl_dereference(t->next); } } t = rtnl_dereference(ip6n->tnls_wc[0]); unregister_netdevice_queue(t->dev, &list); unregister_netdevice_many(&list); } static int __net_init ip6_tnl_init_net(struct net *net) { struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id); int err; ip6n->tnls[0] = ip6n->tnls_wc; ip6n->tnls[1] = ip6n->tnls_r_l; err = -ENOMEM; ip6n->fb_tnl_dev = alloc_netdev(sizeof(struct ip6_tnl), "ip6tnl0", ip6_tnl_dev_setup); if (!ip6n->fb_tnl_dev) goto err_alloc_dev; dev_net_set(ip6n->fb_tnl_dev, net); err = ip6_fb_tnl_dev_init(ip6n->fb_tnl_dev); if (err < 0) goto err_register; err = register_netdev(ip6n->fb_tnl_dev); if (err < 0) goto err_register; return 0; err_register: ip6_dev_free(ip6n->fb_tnl_dev); err_alloc_dev: return err; } static void __net_exit ip6_tnl_exit_net(struct net *net) { struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id); rtnl_lock(); ip6_tnl_destroy_tunnels(ip6n); rtnl_unlock(); } static struct pernet_operations ip6_tnl_net_ops = { .init = ip6_tnl_init_net, .exit = ip6_tnl_exit_net, .id = &ip6_tnl_net_id, .size = sizeof(struct ip6_tnl_net), }; /** * ip6_tunnel_init - register protocol and reserve needed resources * * Return: 0 on success **/ static int __init ip6_tunnel_init(void) { int err; err = register_pernet_device(&ip6_tnl_net_ops); if (err < 0) goto out_pernet; err = xfrm6_tunnel_register(&ip4ip6_handler, AF_INET); if (err < 0) { printk(KERN_ERR "ip6_tunnel init: can't register ip4ip6\n"); goto out_ip4ip6; } err = xfrm6_tunnel_register(&ip6ip6_handler, AF_INET6); if (err < 0) { printk(KERN_ERR "ip6_tunnel init: can't register ip6ip6\n"); goto out_ip6ip6; } return 0; out_ip6ip6: xfrm6_tunnel_deregister(&ip4ip6_handler, AF_INET); out_ip4ip6: unregister_pernet_device(&ip6_tnl_net_ops); out_pernet: return err; } /** * ip6_tunnel_cleanup - free resources and unregister protocol **/ static void __exit ip6_tunnel_cleanup(void) { if (xfrm6_tunnel_deregister(&ip4ip6_handler, AF_INET)) printk(KERN_INFO "ip6_tunnel close: can't deregister ip4ip6\n"); if (xfrm6_tunnel_deregister(&ip6ip6_handler, AF_INET6)) printk(KERN_INFO "ip6_tunnel close: can't deregister ip6ip6\n"); unregister_pernet_device(&ip6_tnl_net_ops); } module_init(ip6_tunnel_init); module_exit(ip6_tunnel_cleanup);