diff options
Diffstat (limited to 'kernel/net/ipv4/ipip.c')
| -rw-r--r-- | kernel/net/ipv4/ipip.c | 569 |
1 files changed, 569 insertions, 0 deletions
diff --git a/kernel/net/ipv4/ipip.c b/kernel/net/ipv4/ipip.c new file mode 100644 index 000000000..ff96396eb --- /dev/null +++ b/kernel/net/ipv4/ipip.c @@ -0,0 +1,569 @@ +/* + * Linux NET3: IP/IP protocol decoder. + * + * Authors: + * Sam Lantinga (slouken@cs.ucdavis.edu) 02/01/95 + * + * Fixes: + * Alan Cox : Merged and made usable non modular (its so tiny its silly as + * a module taking up 2 pages). + * Alan Cox : Fixed bug with 1.3.18 and IPIP not working (now needs to set skb->h.iph) + * to keep ip_forward happy. + * Alan Cox : More fixes for 1.3.21, and firewall fix. Maybe this will work soon 8). + * Kai Schulte : Fixed #defines for IP_FIREWALL->FIREWALL + * David Woodhouse : Perform some basic ICMP handling. + * IPIP Routing without decapsulation. + * Carlos Picoto : GRE over IP support + * Alexey Kuznetsov: Reworked. Really, now it is truncated version of ipv4/ip_gre.c. + * I do not want to merge them together. + * + * 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. + * + */ + +/* tunnel.c: an IP tunnel driver + + The purpose of this driver is to provide an IP tunnel through + which you can tunnel network traffic transparently across subnets. + + This was written by looking at Nick Holloway's dummy driver + Thanks for the great code! + + -Sam Lantinga (slouken@cs.ucdavis.edu) 02/01/95 + + Minor tweaks: + Cleaned up the code a little and added some pre-1.3.0 tweaks. + dev->hard_header/hard_header_len changed to use no headers. + Comments/bracketing tweaked. + Made the tunnels use dev->name not tunnel: when error reporting. + Added tx_dropped stat + + -Alan Cox (alan@lxorguk.ukuu.org.uk) 21 March 95 + + Reworked: + Changed to tunnel to destination gateway in addition to the + tunnel's pointopoint address + Almost completely rewritten + Note: There is currently no firewall or ICMP handling done. + + -Sam Lantinga (slouken@cs.ucdavis.edu) 02/13/96 + +*/ + +/* Things I wish I had known when writing the tunnel driver: + + When the tunnel_xmit() function is called, the skb contains the + packet to be sent (plus a great deal of extra info), and dev + contains the tunnel device that _we_ are. + + When we are passed a packet, we are expected to fill in the + source address with our source IP address. + + What is the proper way to allocate, copy and free a buffer? + After you allocate it, it is a "0 length" chunk of memory + starting at zero. If you want to add headers to the buffer + later, you'll have to call "skb_reserve(skb, amount)" with + the amount of memory you want reserved. Then, you call + "skb_put(skb, amount)" with the amount of space you want in + the buffer. skb_put() returns a pointer to the top (#0) of + that buffer. skb->len is set to the amount of space you have + "allocated" with skb_put(). You can then write up to skb->len + bytes to that buffer. If you need more, you can call skb_put() + again with the additional amount of space you need. You can + find out how much more space you can allocate by calling + "skb_tailroom(skb)". + Now, to add header space, call "skb_push(skb, header_len)". + This creates space at the beginning of the buffer and returns + a pointer to this new space. If later you need to strip a + header from a buffer, call "skb_pull(skb, header_len)". + skb_headroom() will return how much space is left at the top + of the buffer (before the main data). Remember, this headroom + space must be reserved before the skb_put() function is called. + */ + +/* + This version of net/ipv4/ipip.c is cloned of net/ipv4/ip_gre.c + + For comments look at net/ipv4/ip_gre.c --ANK + */ + + +#include <linux/capability.h> +#include <linux/module.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/slab.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/netfilter_ipv4.h> +#include <linux/if_ether.h> + +#include <net/sock.h> +#include <net/ip.h> +#include <net/icmp.h> +#include <net/ip_tunnels.h> +#include <net/inet_ecn.h> +#include <net/xfrm.h> +#include <net/net_namespace.h> +#include <net/netns/generic.h> + +static bool log_ecn_error = true; +module_param(log_ecn_error, bool, 0644); +MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN"); + +static int ipip_net_id __read_mostly; + +static int ipip_tunnel_init(struct net_device *dev); +static struct rtnl_link_ops ipip_link_ops __read_mostly; + +static int ipip_err(struct sk_buff *skb, u32 info) +{ + +/* 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 net *net = dev_net(skb->dev); + struct ip_tunnel_net *itn = net_generic(net, ipip_net_id); + const struct iphdr *iph = (const struct iphdr *)skb->data; + struct ip_tunnel *t; + int err; + const int type = icmp_hdr(skb)->type; + const int code = icmp_hdr(skb)->code; + + err = -ENOENT; + t = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY, + iph->daddr, iph->saddr, 0); + if (!t) + goto out; + + if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) { + ipv4_update_pmtu(skb, dev_net(skb->dev), info, + t->parms.link, 0, IPPROTO_IPIP, 0); + err = 0; + goto out; + } + + if (type == ICMP_REDIRECT) { + ipv4_redirect(skb, dev_net(skb->dev), t->parms.link, 0, + IPPROTO_IPIP, 0); + err = 0; + goto out; + } + + if (t->parms.iph.daddr == 0) + goto out; + + err = 0; + if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED) + goto out; + + if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO)) + t->err_count++; + else + t->err_count = 1; + t->err_time = jiffies; + +out: + return err; +} + +static const struct tnl_ptk_info tpi = { + /* no tunnel info required for ipip. */ + .proto = htons(ETH_P_IP), +}; + +static int ipip_rcv(struct sk_buff *skb) +{ + struct net *net = dev_net(skb->dev); + struct ip_tunnel_net *itn = net_generic(net, ipip_net_id); + struct ip_tunnel *tunnel; + const struct iphdr *iph; + + iph = ip_hdr(skb); + tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY, + iph->saddr, iph->daddr, 0); + if (tunnel) { + if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) + goto drop; + if (iptunnel_pull_header(skb, 0, tpi.proto)) + goto drop; + return ip_tunnel_rcv(tunnel, skb, &tpi, log_ecn_error); + } + + return -1; + +drop: + kfree_skb(skb); + return 0; +} + +/* + * This function assumes it is being called from dev_queue_xmit() + * and that skb is filled properly by that function. + */ +static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev) +{ + struct ip_tunnel *tunnel = netdev_priv(dev); + const struct iphdr *tiph = &tunnel->parms.iph; + + if (unlikely(skb->protocol != htons(ETH_P_IP))) + goto tx_error; + + skb = iptunnel_handle_offloads(skb, false, SKB_GSO_IPIP); + if (IS_ERR(skb)) + goto out; + + skb_set_inner_ipproto(skb, IPPROTO_IPIP); + + ip_tunnel_xmit(skb, dev, tiph, tiph->protocol); + return NETDEV_TX_OK; + +tx_error: + kfree_skb(skb); +out: + dev->stats.tx_errors++; + return NETDEV_TX_OK; +} + +static int +ipip_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) +{ + int err = 0; + struct ip_tunnel_parm p; + + if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) + return -EFAULT; + + if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) { + if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP || + p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF))) + return -EINVAL; + } + + p.i_key = p.o_key = p.i_flags = p.o_flags = 0; + if (p.iph.ttl) + p.iph.frag_off |= htons(IP_DF); + + err = ip_tunnel_ioctl(dev, &p, cmd); + if (err) + return err; + + if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p))) + return -EFAULT; + + return 0; +} + +static const struct net_device_ops ipip_netdev_ops = { + .ndo_init = ipip_tunnel_init, + .ndo_uninit = ip_tunnel_uninit, + .ndo_start_xmit = ipip_tunnel_xmit, + .ndo_do_ioctl = ipip_tunnel_ioctl, + .ndo_change_mtu = ip_tunnel_change_mtu, + .ndo_get_stats64 = ip_tunnel_get_stats64, + .ndo_get_iflink = ip_tunnel_get_iflink, +}; + +#define IPIP_FEATURES (NETIF_F_SG | \ + NETIF_F_FRAGLIST | \ + NETIF_F_HIGHDMA | \ + NETIF_F_GSO_SOFTWARE | \ + NETIF_F_HW_CSUM) + +static void ipip_tunnel_setup(struct net_device *dev) +{ + dev->netdev_ops = &ipip_netdev_ops; + + dev->type = ARPHRD_TUNNEL; + dev->flags = IFF_NOARP; + dev->addr_len = 4; + dev->features |= NETIF_F_LLTX; + netif_keep_dst(dev); + + dev->features |= IPIP_FEATURES; + dev->hw_features |= IPIP_FEATURES; + ip_tunnel_setup(dev, ipip_net_id); +} + +static int ipip_tunnel_init(struct net_device *dev) +{ + struct ip_tunnel *tunnel = netdev_priv(dev); + + memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4); + memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4); + + tunnel->tun_hlen = 0; + tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen; + tunnel->parms.iph.protocol = IPPROTO_IPIP; + return ip_tunnel_init(dev); +} + +static void ipip_netlink_parms(struct nlattr *data[], + struct ip_tunnel_parm *parms) +{ + memset(parms, 0, sizeof(*parms)); + + parms->iph.version = 4; + parms->iph.protocol = IPPROTO_IPIP; + parms->iph.ihl = 5; + + if (!data) + return; + + if (data[IFLA_IPTUN_LINK]) + parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]); + + if (data[IFLA_IPTUN_LOCAL]) + parms->iph.saddr = nla_get_in_addr(data[IFLA_IPTUN_LOCAL]); + + if (data[IFLA_IPTUN_REMOTE]) + parms->iph.daddr = nla_get_in_addr(data[IFLA_IPTUN_REMOTE]); + + if (data[IFLA_IPTUN_TTL]) { + parms->iph.ttl = nla_get_u8(data[IFLA_IPTUN_TTL]); + if (parms->iph.ttl) + parms->iph.frag_off = htons(IP_DF); + } + + if (data[IFLA_IPTUN_TOS]) + parms->iph.tos = nla_get_u8(data[IFLA_IPTUN_TOS]); + + if (!data[IFLA_IPTUN_PMTUDISC] || nla_get_u8(data[IFLA_IPTUN_PMTUDISC])) + parms->iph.frag_off = htons(IP_DF); +} + +/* This function returns true when ENCAP attributes are present in the nl msg */ +static bool ipip_netlink_encap_parms(struct nlattr *data[], + struct ip_tunnel_encap *ipencap) +{ + bool ret = false; + + memset(ipencap, 0, sizeof(*ipencap)); + + if (!data) + return ret; + + if (data[IFLA_IPTUN_ENCAP_TYPE]) { + ret = true; + ipencap->type = nla_get_u16(data[IFLA_IPTUN_ENCAP_TYPE]); + } + + if (data[IFLA_IPTUN_ENCAP_FLAGS]) { + ret = true; + ipencap->flags = nla_get_u16(data[IFLA_IPTUN_ENCAP_FLAGS]); + } + + if (data[IFLA_IPTUN_ENCAP_SPORT]) { + ret = true; + ipencap->sport = nla_get_be16(data[IFLA_IPTUN_ENCAP_SPORT]); + } + + if (data[IFLA_IPTUN_ENCAP_DPORT]) { + ret = true; + ipencap->dport = nla_get_be16(data[IFLA_IPTUN_ENCAP_DPORT]); + } + + return ret; +} + +static int ipip_newlink(struct net *src_net, struct net_device *dev, + struct nlattr *tb[], struct nlattr *data[]) +{ + struct ip_tunnel_parm p; + struct ip_tunnel_encap ipencap; + + if (ipip_netlink_encap_parms(data, &ipencap)) { + struct ip_tunnel *t = netdev_priv(dev); + int err = ip_tunnel_encap_setup(t, &ipencap); + + if (err < 0) + return err; + } + + ipip_netlink_parms(data, &p); + return ip_tunnel_newlink(dev, tb, &p); +} + +static int ipip_changelink(struct net_device *dev, struct nlattr *tb[], + struct nlattr *data[]) +{ + struct ip_tunnel_parm p; + struct ip_tunnel_encap ipencap; + + if (ipip_netlink_encap_parms(data, &ipencap)) { + struct ip_tunnel *t = netdev_priv(dev); + int err = ip_tunnel_encap_setup(t, &ipencap); + + if (err < 0) + return err; + } + + ipip_netlink_parms(data, &p); + + if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) || + (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr)) + return -EINVAL; + + return ip_tunnel_changelink(dev, tb, &p); +} + +static size_t ipip_get_size(const struct net_device *dev) +{ + return + /* IFLA_IPTUN_LINK */ + nla_total_size(4) + + /* IFLA_IPTUN_LOCAL */ + nla_total_size(4) + + /* IFLA_IPTUN_REMOTE */ + nla_total_size(4) + + /* IFLA_IPTUN_TTL */ + nla_total_size(1) + + /* IFLA_IPTUN_TOS */ + nla_total_size(1) + + /* IFLA_IPTUN_PMTUDISC */ + nla_total_size(1) + + /* IFLA_IPTUN_ENCAP_TYPE */ + nla_total_size(2) + + /* IFLA_IPTUN_ENCAP_FLAGS */ + nla_total_size(2) + + /* IFLA_IPTUN_ENCAP_SPORT */ + nla_total_size(2) + + /* IFLA_IPTUN_ENCAP_DPORT */ + nla_total_size(2) + + 0; +} + +static int ipip_fill_info(struct sk_buff *skb, const struct net_device *dev) +{ + struct ip_tunnel *tunnel = netdev_priv(dev); + struct ip_tunnel_parm *parm = &tunnel->parms; + + if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) || + nla_put_in_addr(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) || + nla_put_in_addr(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) || + nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) || + nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) || + nla_put_u8(skb, IFLA_IPTUN_PMTUDISC, + !!(parm->iph.frag_off & htons(IP_DF)))) + goto nla_put_failure; + + if (nla_put_u16(skb, IFLA_IPTUN_ENCAP_TYPE, + tunnel->encap.type) || + nla_put_be16(skb, IFLA_IPTUN_ENCAP_SPORT, + tunnel->encap.sport) || + nla_put_be16(skb, IFLA_IPTUN_ENCAP_DPORT, + tunnel->encap.dport) || + nla_put_u16(skb, IFLA_IPTUN_ENCAP_FLAGS, + tunnel->encap.flags)) + goto nla_put_failure; + + return 0; + +nla_put_failure: + return -EMSGSIZE; +} + +static const struct nla_policy ipip_policy[IFLA_IPTUN_MAX + 1] = { + [IFLA_IPTUN_LINK] = { .type = NLA_U32 }, + [IFLA_IPTUN_LOCAL] = { .type = NLA_U32 }, + [IFLA_IPTUN_REMOTE] = { .type = NLA_U32 }, + [IFLA_IPTUN_TTL] = { .type = NLA_U8 }, + [IFLA_IPTUN_TOS] = { .type = NLA_U8 }, + [IFLA_IPTUN_PMTUDISC] = { .type = NLA_U8 }, + [IFLA_IPTUN_ENCAP_TYPE] = { .type = NLA_U16 }, + [IFLA_IPTUN_ENCAP_FLAGS] = { .type = NLA_U16 }, + [IFLA_IPTUN_ENCAP_SPORT] = { .type = NLA_U16 }, + [IFLA_IPTUN_ENCAP_DPORT] = { .type = NLA_U16 }, +}; + +static struct rtnl_link_ops ipip_link_ops __read_mostly = { + .kind = "ipip", + .maxtype = IFLA_IPTUN_MAX, + .policy = ipip_policy, + .priv_size = sizeof(struct ip_tunnel), + .setup = ipip_tunnel_setup, + .newlink = ipip_newlink, + .changelink = ipip_changelink, + .dellink = ip_tunnel_dellink, + .get_size = ipip_get_size, + .fill_info = ipip_fill_info, + .get_link_net = ip_tunnel_get_link_net, +}; + +static struct xfrm_tunnel ipip_handler __read_mostly = { + .handler = ipip_rcv, + .err_handler = ipip_err, + .priority = 1, +}; + +static int __net_init ipip_init_net(struct net *net) +{ + return ip_tunnel_init_net(net, ipip_net_id, &ipip_link_ops, "tunl0"); +} + +static void __net_exit ipip_exit_net(struct net *net) +{ + struct ip_tunnel_net *itn = net_generic(net, ipip_net_id); + ip_tunnel_delete_net(itn, &ipip_link_ops); +} + +static struct pernet_operations ipip_net_ops = { + .init = ipip_init_net, + .exit = ipip_exit_net, + .id = &ipip_net_id, + .size = sizeof(struct ip_tunnel_net), +}; + +static int __init ipip_init(void) +{ + int err; + + pr_info("ipip: IPv4 over IPv4 tunneling driver\n"); + + err = register_pernet_device(&ipip_net_ops); + if (err < 0) + return err; + err = xfrm4_tunnel_register(&ipip_handler, AF_INET); + if (err < 0) { + pr_info("%s: can't register tunnel\n", __func__); + goto xfrm_tunnel_failed; + } + err = rtnl_link_register(&ipip_link_ops); + if (err < 0) + goto rtnl_link_failed; + +out: + return err; + +rtnl_link_failed: + xfrm4_tunnel_deregister(&ipip_handler, AF_INET); +xfrm_tunnel_failed: + unregister_pernet_device(&ipip_net_ops); + goto out; +} + +static void __exit ipip_fini(void) +{ + rtnl_link_unregister(&ipip_link_ops); + if (xfrm4_tunnel_deregister(&ipip_handler, AF_INET)) + pr_info("%s: can't deregister tunnel\n", __func__); + + unregister_pernet_device(&ipip_net_ops); +} + +module_init(ipip_init); +module_exit(ipip_fini); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_RTNL_LINK("ipip"); +MODULE_ALIAS_NETDEV("tunl0"); |