diff options
Diffstat (limited to 'net/ipv4/ip_gre.c')
| -rw-r--r-- | net/ipv4/ip_gre.c | 1366 |
1 files changed, 1366 insertions, 0 deletions
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c new file mode 100644 index 000000000000..900ee28bda99 --- /dev/null +++ b/net/ipv4/ip_gre.c @@ -0,0 +1,1366 @@ +/* + * Linux NET3: GRE over IP protocol decoder. + * + * Authors: Alexey Kuznetsov (kuznet@ms2.inr.ac.ru) + * + * 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. + * + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#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/if_vlan.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 <linux/if_ether.h> + +#include <net/sock.h> +#include <net/ip.h> +#include <net/icmp.h> +#include <net/protocol.h> +#include <net/ip_tunnels.h> +#include <net/arp.h> +#include <net/checksum.h> +#include <net/dsfield.h> +#include <net/inet_ecn.h> +#include <net/xfrm.h> +#include <net/net_namespace.h> +#include <net/netns/generic.h> +#include <net/rtnetlink.h> +#include <net/gre.h> +#include <net/dst_metadata.h> + +#if IS_ENABLED(CONFIG_IPV6) +#include <net/ipv6.h> +#include <net/ip6_fib.h> +#include <net/ip6_route.h> +#endif + +/* + Problems & solutions + -------------------- + + 1. The most important issue is detecting local dead loops. + They would cause complete host lockup in transmit, which + would be "resolved" by stack overflow or, if queueing is enabled, + with infinite looping in net_bh. + + We cannot track such dead loops during route installation, + it is infeasible task. The most general solutions would be + to keep skb->encapsulation counter (sort of local ttl), + and silently drop packet when it expires. It is a good + solution, but it supposes maintaining new variable in ALL + skb, even if no tunneling is used. + + Current solution: xmit_recursion breaks dead loops. This is a percpu + counter, since when we enter the first ndo_xmit(), cpu migration is + forbidden. We force an exit if this counter reaches RECURSION_LIMIT + + 2. Networking dead loops would not kill routers, but would really + kill network. IP hop limit plays role of "t->recursion" in this case, + if we copy it from packet being encapsulated to upper header. + It is very good solution, but it introduces two problems: + + - Routing protocols, using packets with ttl=1 (OSPF, RIP2), + do not work over tunnels. + - traceroute does not work. I planned to relay ICMP from tunnel, + so that this problem would be solved and traceroute output + would even more informative. This idea appeared to be wrong: + only Linux complies to rfc1812 now (yes, guys, Linux is the only + true router now :-)), all routers (at least, in neighbourhood of mine) + return only 8 bytes of payload. It is the end. + + Hence, if we want that OSPF worked or traceroute said something reasonable, + we should search for another solution. + + One of them is to parse packet trying to detect inner encapsulation + made by our node. It is difficult or even impossible, especially, + taking into account fragmentation. TO be short, ttl is not solution at all. + + Current solution: The solution was UNEXPECTEDLY SIMPLE. + We force DF flag on tunnels with preconfigured hop limit, + that is ALL. :-) Well, it does not remove the problem completely, + but exponential growth of network traffic is changed to linear + (branches, that exceed pmtu are pruned) and tunnel mtu + rapidly degrades to value <68, where looping stops. + Yes, it is not good if there exists a router in the loop, + which does not force DF, even when encapsulating packets have DF set. + But it is not our problem! Nobody could accuse us, we made + all that we could make. Even if it is your gated who injected + fatal route to network, even if it were you who configured + fatal static route: you are innocent. :-) + + Alexey Kuznetsov. + */ + +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 struct rtnl_link_ops ipgre_link_ops __read_mostly; +static int ipgre_tunnel_init(struct net_device *dev); + +static int ipgre_net_id __read_mostly; +static int gre_tap_net_id __read_mostly; + +static int ip_gre_calc_hlen(__be16 o_flags) +{ + int addend = 4; + + if (o_flags & TUNNEL_CSUM) + addend += 4; + if (o_flags & TUNNEL_KEY) + addend += 4; + if (o_flags & TUNNEL_SEQ) + addend += 4; + return addend; +} + +static __be16 gre_flags_to_tnl_flags(__be16 flags) +{ + __be16 tflags = 0; + + if (flags & GRE_CSUM) + tflags |= TUNNEL_CSUM; + if (flags & GRE_ROUTING) + tflags |= TUNNEL_ROUTING; + if (flags & GRE_KEY) + tflags |= TUNNEL_KEY; + if (flags & GRE_SEQ) + tflags |= TUNNEL_SEQ; + if (flags & GRE_STRICT) + tflags |= TUNNEL_STRICT; + if (flags & GRE_REC) + tflags |= TUNNEL_REC; + if (flags & GRE_VERSION) + tflags |= TUNNEL_VERSION; + + return tflags; +} + +static __be16 tnl_flags_to_gre_flags(__be16 tflags) +{ + __be16 flags = 0; + + if (tflags & TUNNEL_CSUM) + flags |= GRE_CSUM; + if (tflags & TUNNEL_ROUTING) + flags |= GRE_ROUTING; + if (tflags & TUNNEL_KEY) + flags |= GRE_KEY; + if (tflags & TUNNEL_SEQ) + flags |= GRE_SEQ; + if (tflags & TUNNEL_STRICT) + flags |= GRE_STRICT; + if (tflags & TUNNEL_REC) + flags |= GRE_REC; + if (tflags & TUNNEL_VERSION) + flags |= GRE_VERSION; + + return flags; +} + +/* Fills in tpi and returns header length to be pulled. */ +static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi, + bool *csum_err) +{ + const struct gre_base_hdr *greh; + __be32 *options; + int hdr_len; + + if (unlikely(!pskb_may_pull(skb, sizeof(struct gre_base_hdr)))) + return -EINVAL; + + greh = (struct gre_base_hdr *)skb_transport_header(skb); + if (unlikely(greh->flags & (GRE_VERSION | GRE_ROUTING))) + return -EINVAL; + + tpi->flags = gre_flags_to_tnl_flags(greh->flags); + hdr_len = ip_gre_calc_hlen(tpi->flags); + + if (!pskb_may_pull(skb, hdr_len)) + return -EINVAL; + + greh = (struct gre_base_hdr *)skb_transport_header(skb); + tpi->proto = greh->protocol; + + options = (__be32 *)(greh + 1); + if (greh->flags & GRE_CSUM) { + if (skb_checksum_simple_validate(skb)) { + *csum_err = true; + return -EINVAL; + } + + skb_checksum_try_convert(skb, IPPROTO_GRE, 0, + null_compute_pseudo); + options++; + } + + if (greh->flags & GRE_KEY) { + tpi->key = *options; + options++; + } else { + tpi->key = 0; + } + if (unlikely(greh->flags & GRE_SEQ)) { + tpi->seq = *options; + options++; + } else { + tpi->seq = 0; + } + /* WCCP version 1 and 2 protocol decoding. + * - Change protocol to IP + * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header + */ + if (greh->flags == 0 && tpi->proto == htons(ETH_P_WCCP)) { + tpi->proto = htons(ETH_P_IP); + if ((*(u8 *)options & 0xF0) != 0x40) { + hdr_len += 4; + if (!pskb_may_pull(skb, hdr_len)) + return -EINVAL; + } + } + return hdr_len; +} + +static void ipgre_err(struct sk_buff *skb, u32 info, + const struct tnl_ptk_info *tpi) +{ + + /* 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. + + Moreover, Cisco "wise men" put GRE key to the third word + in GRE header. It makes impossible maintaining even soft + state for keyed GRE tunnels with enabled checksum. Tell + them "thank you". + + Well, I wonder, rfc1812 was written by Cisco employee, + what the hell these idiots break standards established + by themselves??? + */ + struct net *net = dev_net(skb->dev); + struct ip_tunnel_net *itn; + const struct iphdr *iph; + const int type = icmp_hdr(skb)->type; + const int code = icmp_hdr(skb)->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; + 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; + + case ICMP_REDIRECT: + break; + } + + if (tpi->proto == htons(ETH_P_TEB)) + itn = net_generic(net, gre_tap_net_id); + else + itn = net_generic(net, ipgre_net_id); + + iph = (const struct iphdr *)(icmp_hdr(skb) + 1); + t = ip_tunnel_lookup(itn, skb->dev->ifindex, tpi->flags, + iph->daddr, iph->saddr, tpi->key); + + if (!t) + return; + + if (t->parms.iph.daddr == 0 || + ipv4_is_multicast(t->parms.iph.daddr)) + return; + + if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED) + return; + + if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO)) + t->err_count++; + else + t->err_count = 1; + t->err_time = jiffies; +} + +static void gre_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. + * + * Moreover, Cisco "wise men" put GRE key to the third word + * in GRE header. It makes impossible maintaining even soft + * state for keyed + * GRE tunnels with enabled checksum. Tell them "thank you". + * + * Well, I wonder, rfc1812 was written by Cisco employee, + * what the hell these idiots break standards established + * by themselves??? + */ + + const int type = icmp_hdr(skb)->type; + const int code = icmp_hdr(skb)->code; + struct tnl_ptk_info tpi; + bool csum_err = false; + + if (parse_gre_header(skb, &tpi, &csum_err) < 0) { + if (!csum_err) /* ignore csum errors. */ + return; + } + + if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) { + ipv4_update_pmtu(skb, dev_net(skb->dev), info, + skb->dev->ifindex, 0, IPPROTO_GRE, 0); + return; + } + if (type == ICMP_REDIRECT) { + ipv4_redirect(skb, dev_net(skb->dev), skb->dev->ifindex, 0, + IPPROTO_GRE, 0); + return; + } + + ipgre_err(skb, info, &tpi); +} + +static __be64 key_to_tunnel_id(__be32 key) +{ +#ifdef __BIG_ENDIAN + return (__force __be64)((__force u32)key); +#else + return (__force __be64)((__force u64)key << 32); +#endif +} + +/* Returns the least-significant 32 bits of a __be64. */ +static __be32 tunnel_id_to_key(__be64 x) +{ +#ifdef __BIG_ENDIAN + return (__force __be32)x; +#else + return (__force __be32)((__force u64)x >> 32); +#endif +} + +static int ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi) +{ + struct net *net = dev_net(skb->dev); + struct metadata_dst *tun_dst = NULL; + struct ip_tunnel_net *itn; + const struct iphdr *iph; + struct ip_tunnel *tunnel; + + if (tpi->proto == htons(ETH_P_TEB)) + itn = net_generic(net, gre_tap_net_id); + else + itn = net_generic(net, ipgre_net_id); + + iph = ip_hdr(skb); + tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, tpi->flags, + iph->saddr, iph->daddr, tpi->key); + + if (tunnel) { + if (tunnel->dev->type != ARPHRD_NONE) + skb_pop_mac_header(skb); + else + skb_reset_mac_header(skb); + if (tunnel->collect_md) { + __be16 flags; + __be64 tun_id; + + flags = tpi->flags & (TUNNEL_CSUM | TUNNEL_KEY); + tun_id = key_to_tunnel_id(tpi->key); + tun_dst = ip_tun_rx_dst(skb, flags, tun_id, 0); + if (!tun_dst) + return PACKET_REJECT; + } + + ip_tunnel_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error); + return PACKET_RCVD; + } + return PACKET_REJECT; +} + +static int gre_rcv(struct sk_buff *skb) +{ + struct tnl_ptk_info tpi; + bool csum_err = false; + int hdr_len; + +#ifdef CONFIG_NET_IPGRE_BROADCAST + if (ipv4_is_multicast(ip_hdr(skb)->daddr)) { + /* Looped back packet, drop it! */ + if (rt_is_output_route(skb_rtable(skb))) + goto drop; + } +#endif + + hdr_len = parse_gre_header(skb, &tpi, &csum_err); + if (hdr_len < 0) + goto drop; + if (iptunnel_pull_header(skb, hdr_len, tpi.proto) < 0) + goto drop; + + if (ipgre_rcv(skb, &tpi) == PACKET_RCVD) + return 0; + + icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0); +drop: + kfree_skb(skb); + return 0; +} + +static void build_header(struct sk_buff *skb, int hdr_len, __be16 flags, + __be16 proto, __be32 key, __be32 seq) +{ + struct gre_base_hdr *greh; + + skb_push(skb, hdr_len); + + skb_reset_transport_header(skb); + greh = (struct gre_base_hdr *)skb->data; + greh->flags = tnl_flags_to_gre_flags(flags); + greh->protocol = proto; + + if (flags & (TUNNEL_KEY | TUNNEL_CSUM | TUNNEL_SEQ)) { + __be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4); + + if (flags & TUNNEL_SEQ) { + *ptr = seq; + ptr--; + } + if (flags & TUNNEL_KEY) { + *ptr = key; + ptr--; + } + if (flags & TUNNEL_CSUM && + !(skb_shinfo(skb)->gso_type & + (SKB_GSO_GRE | SKB_GSO_GRE_CSUM))) { + *ptr = 0; + *(__sum16 *)ptr = csum_fold(skb_checksum(skb, 0, + skb->len, 0)); + } + } +} + +static void __gre_xmit(struct sk_buff *skb, struct net_device *dev, + const struct iphdr *tnl_params, + __be16 proto) +{ + struct ip_tunnel *tunnel = netdev_priv(dev); + + if (tunnel->parms.o_flags & TUNNEL_SEQ) + tunnel->o_seqno++; + + /* Push GRE header. */ + build_header(skb, tunnel->tun_hlen, tunnel->parms.o_flags, + proto, tunnel->parms.o_key, htonl(tunnel->o_seqno)); + + skb_set_inner_protocol(skb, proto); + ip_tunnel_xmit(skb, dev, tnl_params, tnl_params->protocol); +} + +static struct sk_buff *gre_handle_offloads(struct sk_buff *skb, + bool csum) +{ + return iptunnel_handle_offloads(skb, csum, + csum ? SKB_GSO_GRE_CSUM : SKB_GSO_GRE); +} + +static struct rtable *gre_get_rt(struct sk_buff *skb, + struct net_device *dev, + struct flowi4 *fl, + const struct ip_tunnel_key *key) +{ + struct net *net = dev_net(dev); + + memset(fl, 0, sizeof(*fl)); + fl->daddr = key->u.ipv4.dst; + fl->saddr = key->u.ipv4.src; + fl->flowi4_tos = RT_TOS(key->tos); + fl->flowi4_mark = skb->mark; + fl->flowi4_proto = IPPROTO_GRE; + + return ip_route_output_key(net, fl); +} + +static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev, + __be16 proto) +{ + struct ip_tunnel_info *tun_info; + const struct ip_tunnel_key *key; + struct flowi4 fl; + struct rtable *rt; + int min_headroom; + int tunnel_hlen; + __be16 df, flags; + int err; + + tun_info = skb_tunnel_info(skb); + if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) || + ip_tunnel_info_af(tun_info) != AF_INET)) + goto err_free_skb; + + key = &tun_info->key; + rt = gre_get_rt(skb, dev, &fl, key); + if (IS_ERR(rt)) + goto err_free_skb; + + tunnel_hlen = ip_gre_calc_hlen(key->tun_flags); + + min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len + + tunnel_hlen + sizeof(struct iphdr); + if (skb_headroom(skb) < min_headroom || skb_header_cloned(skb)) { + int head_delta = SKB_DATA_ALIGN(min_headroom - + skb_headroom(skb) + + 16); + err = pskb_expand_head(skb, max_t(int, head_delta, 0), + 0, GFP_ATOMIC); + if (unlikely(err)) + goto err_free_rt; + } + + /* Push Tunnel header. */ + skb = gre_handle_offloads(skb, !!(tun_info->key.tun_flags & TUNNEL_CSUM)); + if (IS_ERR(skb)) { + skb = NULL; + goto err_free_rt; + } + + flags = tun_info->key.tun_flags & (TUNNEL_CSUM | TUNNEL_KEY); + build_header(skb, tunnel_hlen, flags, proto, + tunnel_id_to_key(tun_info->key.tun_id), 0); + + df = key->tun_flags & TUNNEL_DONT_FRAGMENT ? htons(IP_DF) : 0; + err = iptunnel_xmit(skb->sk, rt, skb, fl.saddr, + key->u.ipv4.dst, IPPROTO_GRE, + key->tos, key->ttl, df, false); + iptunnel_xmit_stats(err, &dev->stats, dev->tstats); + return; + +err_free_rt: + ip_rt_put(rt); +err_free_skb: + kfree_skb(skb); + dev->stats.tx_dropped++; +} + +static int gre_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb) +{ + struct ip_tunnel_info *info = skb_tunnel_info(skb); + struct rtable *rt; + struct flowi4 fl4; + + if (ip_tunnel_info_af(info) != AF_INET) + return -EINVAL; + + rt = gre_get_rt(skb, dev, &fl4, &info->key); + if (IS_ERR(rt)) + return PTR_ERR(rt); + + ip_rt_put(rt); + info->key.u.ipv4.src = fl4.saddr; + return 0; +} + +static netdev_tx_t ipgre_xmit(struct sk_buff *skb, + struct net_device *dev) +{ + struct ip_tunnel *tunnel = netdev_priv(dev); + const struct iphdr *tnl_params; + + if (tunnel->collect_md) { + gre_fb_xmit(skb, dev, skb->protocol); + return NETDEV_TX_OK; + } + + if (dev->header_ops) { + /* Need space for new headers */ + if (skb_cow_head(skb, dev->needed_headroom - + (tunnel->hlen + sizeof(struct iphdr)))) + goto free_skb; + + tnl_params = (const struct iphdr *)skb->data; + + /* Pull skb since ip_tunnel_xmit() needs skb->data pointing + * to gre header. + */ + skb_pull(skb, tunnel->hlen + sizeof(struct iphdr)); + skb_reset_mac_header(skb); + } else { + if (skb_cow_head(skb, dev->needed_headroom)) + goto free_skb; + + tnl_params = &tunnel->parms.iph; + } + + skb = gre_handle_offloads(skb, !!(tunnel->parms.o_flags&TUNNEL_CSUM)); + if (IS_ERR(skb)) + goto out; + + __gre_xmit(skb, dev, tnl_params, skb->protocol); + return NETDEV_TX_OK; + +free_skb: + kfree_skb(skb); +out: + dev->stats.tx_dropped++; + return NETDEV_TX_OK; +} + +static netdev_tx_t gre_tap_xmit(struct sk_buff *skb, + struct net_device *dev) +{ + struct ip_tunnel *tunnel = netdev_priv(dev); + + if (tunnel->collect_md) { + gre_fb_xmit(skb, dev, htons(ETH_P_TEB)); + return NETDEV_TX_OK; + } + + skb = gre_handle_offloads(skb, !!(tunnel->parms.o_flags&TUNNEL_CSUM)); + if (IS_ERR(skb)) + goto out; + + if (skb_cow_head(skb, dev->needed_headroom)) + goto free_skb; + + __gre_xmit(skb, dev, &tunnel->parms.iph, htons(ETH_P_TEB)); + return NETDEV_TX_OK; + +free_skb: + kfree_skb(skb); +out: + dev->stats.tx_dropped++; + return NETDEV_TX_OK; +} + +static int ipgre_tunnel_ioctl(struct net_device *dev, + struct ifreq *ifr, int cmd) +{ + int err; + 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_GRE || + p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)) || + ((p.i_flags|p.o_flags)&(GRE_VERSION|GRE_ROUTING))) + return -EINVAL; + } + p.i_flags = gre_flags_to_tnl_flags(p.i_flags); + p.o_flags = gre_flags_to_tnl_flags(p.o_flags); + + err = ip_tunnel_ioctl(dev, &p, cmd); + if (err) + return err; + + p.i_flags = tnl_flags_to_gre_flags(p.i_flags); + p.o_flags = tnl_flags_to_gre_flags(p.o_flags); + + if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p))) + return -EFAULT; + return 0; +} + +/* Nice toy. Unfortunately, useless in real life :-) + It allows to construct virtual multiprotocol broadcast "LAN" + over the Internet, provided multicast routing is tuned. + + + I have no idea was this bicycle invented before me, + so that I had to set ARPHRD_IPGRE to a random value. + I have an impression, that Cisco could make something similar, + but this feature is apparently missing in IOS<=11.2(8). + + I set up 10.66.66/24 and fec0:6666:6666::0/96 as virtual networks + with broadcast 224.66.66.66. If you have access to mbone, play with me :-) + + ping -t 255 224.66.66.66 + + If nobody answers, mbone does not work. + + ip tunnel add Universe mode gre remote 224.66.66.66 local <Your_real_addr> ttl 255 + ip addr add 10.66.66.<somewhat>/24 dev Universe + ifconfig Universe up + ifconfig Universe add fe80::<Your_real_addr>/10 + ifconfig Universe add fec0:6666:6666::<Your_real_addr>/96 + ftp 10.66.66.66 + ... + ftp fec0:6666:6666::193.233.7.65 + ... + */ +static int ipgre_header(struct sk_buff *skb, struct net_device *dev, + unsigned short type, + const void *daddr, const void *saddr, unsigned int len) +{ + struct ip_tunnel *t = netdev_priv(dev); + struct iphdr *iph; + struct gre_base_hdr *greh; + + iph = (struct iphdr *)skb_push(skb, t->hlen + sizeof(*iph)); + greh = (struct gre_base_hdr *)(iph+1); + greh->flags = tnl_flags_to_gre_flags(t->parms.o_flags); + greh->protocol = htons(type); + + memcpy(iph, &t->parms.iph, sizeof(struct iphdr)); + + /* Set the source hardware address. */ + if (saddr) + memcpy(&iph->saddr, saddr, 4); + if (daddr) + memcpy(&iph->daddr, daddr, 4); + if (iph->daddr) + return t->hlen + sizeof(*iph); + + return -(t->hlen + sizeof(*iph)); +} + +static int ipgre_header_parse(const struct sk_buff *skb, unsigned char *haddr) +{ + const struct iphdr *iph = (const struct iphdr *) skb_mac_header(skb); + memcpy(haddr, &iph->saddr, 4); + return 4; +} + +static const struct header_ops ipgre_header_ops = { + .create = ipgre_header, + .parse = ipgre_header_parse, +}; + +#ifdef CONFIG_NET_IPGRE_BROADCAST +static int ipgre_open(struct net_device *dev) +{ + struct ip_tunnel *t = netdev_priv(dev); + + if (ipv4_is_multicast(t->parms.iph.daddr)) { + struct flowi4 fl4; + struct rtable *rt; + + rt = ip_route_output_gre(t->net, &fl4, + t->parms.iph.daddr, + t->parms.iph.saddr, + t->parms.o_key, + RT_TOS(t->parms.iph.tos), + t->parms.link); + if (IS_ERR(rt)) + return -EADDRNOTAVAIL; + dev = rt->dst.dev; + ip_rt_put(rt); + if (!__in_dev_get_rtnl(dev)) + return -EADDRNOTAVAIL; + t->mlink = dev->ifindex; + ip_mc_inc_group(__in_dev_get_rtnl(dev), t->parms.iph.daddr); + } + return 0; +} + +static int ipgre_close(struct net_device *dev) +{ + struct ip_tunnel *t = netdev_priv(dev); + + if (ipv4_is_multicast(t->parms.iph.daddr) && t->mlink) { + struct in_device *in_dev; + in_dev = inetdev_by_index(t->net, t->mlink); + if (in_dev) + ip_mc_dec_group(in_dev, t->parms.iph.daddr); + } + return 0; +} +#endif + +static const struct net_device_ops ipgre_netdev_ops = { + .ndo_init = ipgre_tunnel_init, + .ndo_uninit = ip_tunnel_uninit, +#ifdef CONFIG_NET_IPGRE_BROADCAST + .ndo_open = ipgre_open, + .ndo_stop = ipgre_close, +#endif + .ndo_start_xmit = ipgre_xmit, + .ndo_do_ioctl = ipgre_tunnel_ioctl, + .ndo_change_mtu = ip_tunnel_change_mtu, + .ndo_get_stats64 = ip_tunnel_get_stats64, + .ndo_get_iflink = ip_tunnel_get_iflink, +}; + +#define GRE_FEATURES (NETIF_F_SG | \ + NETIF_F_FRAGLIST | \ + NETIF_F_HIGHDMA | \ + NETIF_F_HW_CSUM) + +static void ipgre_tunnel_setup(struct net_device *dev) +{ + dev->netdev_ops = &ipgre_netdev_ops; + dev->type = ARPHRD_IPGRE; + ip_tunnel_setup(dev, ipgre_net_id); +} + +static void __gre_tunnel_init(struct net_device *dev) +{ + struct ip_tunnel *tunnel; + int t_hlen; + + tunnel = netdev_priv(dev); + tunnel->tun_hlen = ip_gre_calc_hlen(tunnel->parms.o_flags); + tunnel->parms.iph.protocol = IPPROTO_GRE; + + tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen; + + t_hlen = tunnel->hlen + sizeof(struct iphdr); + + dev->needed_headroom = LL_MAX_HEADER + t_hlen + 4; + dev->mtu = ETH_DATA_LEN - t_hlen - 4; + + dev->features |= GRE_FEATURES; + dev->hw_features |= GRE_FEATURES; + + if (!(tunnel->parms.o_flags & TUNNEL_SEQ)) { + /* TCP offload with GRE SEQ is not supported, nor + * can we support 2 levels of outer headers requiring + * an update. + */ + if (!(tunnel->parms.o_flags & TUNNEL_CSUM) || + (tunnel->encap.type == TUNNEL_ENCAP_NONE)) { + dev->features |= NETIF_F_GSO_SOFTWARE; + dev->hw_features |= NETIF_F_GSO_SOFTWARE; + } + + /* Can use a lockless transmit, unless we generate + * output sequences + */ + dev->features |= NETIF_F_LLTX; + } +} + +static int ipgre_tunnel_init(struct net_device *dev) +{ + struct ip_tunnel *tunnel = netdev_priv(dev); + struct iphdr *iph = &tunnel->parms.iph; + + __gre_tunnel_init(dev); + + memcpy(dev->dev_addr, &iph->saddr, 4); + memcpy(dev->broadcast, &iph->daddr, 4); + + dev->flags = IFF_NOARP; + netif_keep_dst(dev); + dev->addr_len = 4; + + if (iph->daddr && !tunnel->collect_md) { +#ifdef CONFIG_NET_IPGRE_BROADCAST + if (ipv4_is_multicast(iph->daddr)) { + if (!iph->saddr) + return -EINVAL; + dev->flags = IFF_BROADCAST; + dev->header_ops = &ipgre_header_ops; + } +#endif + } else if (!tunnel->collect_md) { + dev->header_ops = &ipgre_header_ops; + } + + return ip_tunnel_init(dev); +} + +static const struct gre_protocol ipgre_protocol = { + .handler = gre_rcv, + .err_handler = gre_err, +}; + +static int __net_init ipgre_init_net(struct net *net) +{ + return ip_tunnel_init_net(net, ipgre_net_id, &ipgre_link_ops, NULL); +} + +static void __net_exit ipgre_exit_net(struct net *net) +{ + struct ip_tunnel_net *itn = net_generic(net, ipgre_net_id); + ip_tunnel_delete_net(itn, &ipgre_link_ops); +} + +static struct pernet_operations ipgre_net_ops = { + .init = ipgre_init_net, + .exit = ipgre_exit_net, + .id = &ipgre_net_id, + .size = sizeof(struct ip_tunnel_net), +}; + +static int ipgre_tunnel_validate(struct nlattr *tb[], struct nlattr *data[]) +{ + __be16 flags; + + if (!data) + return 0; + + flags = 0; + if (data[IFLA_GRE_IFLAGS]) + flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]); + if (data[IFLA_GRE_OFLAGS]) + flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]); + if (flags & (GRE_VERSION|GRE_ROUTING)) + return -EINVAL; + + if (data[IFLA_GRE_COLLECT_METADATA] && + data[IFLA_GRE_ENCAP_TYPE] && + nla_get_u16(data[IFLA_GRE_ENCAP_TYPE]) != TUNNEL_ENCAP_NONE) + return -EINVAL; + + return 0; +} + +static int ipgre_tap_validate(struct nlattr *tb[], struct nlattr *data[]) +{ + __be32 daddr; + + if (tb[IFLA_ADDRESS]) { + if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN) + return -EINVAL; + if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) + return -EADDRNOTAVAIL; + } + + if (!data) + goto out; + + if (data[IFLA_GRE_REMOTE]) { + memcpy(&daddr, nla_data(data[IFLA_GRE_REMOTE]), 4); + if (!daddr) + return -EINVAL; + } + +out: + return ipgre_tunnel_validate(tb, data); +} + +static void ipgre_netlink_parms(struct net_device *dev, + struct nlattr *data[], + struct nlattr *tb[], + struct ip_tunnel_parm *parms) +{ + memset(parms, 0, sizeof(*parms)); + + parms->iph.protocol = IPPROTO_GRE; + + if (!data) + return; + + if (data[IFLA_GRE_LINK]) + parms->link = nla_get_u32(data[IFLA_GRE_LINK]); + + if (data[IFLA_GRE_IFLAGS]) + parms->i_flags = gre_flags_to_tnl_flags(nla_get_be16(data[IFLA_GRE_IFLAGS])); + + if (data[IFLA_GRE_OFLAGS]) + parms->o_flags = gre_flags_to_tnl_flags(nla_get_be16(data[IFLA_GRE_OFLAGS])); + + if (data[IFLA_GRE_IKEY]) + parms->i_key = nla_get_be32(data[IFLA_GRE_IKEY]); + + if (data[IFLA_GRE_OKEY]) + parms->o_key = nla_get_be32(data[IFLA_GRE_OKEY]); + + if (data[IFLA_GRE_LOCAL]) + parms->iph.saddr = nla_get_in_addr(data[IFLA_GRE_LOCAL]); + + if (data[IFLA_GRE_REMOTE]) + parms->iph.daddr = nla_get_in_addr(data[IFLA_GRE_REMOTE]); + + if (data[IFLA_GRE_TTL]) + parms->iph.ttl = nla_get_u8(data[IFLA_GRE_TTL]); + + if (data[IFLA_GRE_TOS]) + parms->iph.tos = nla_get_u8(data[IFLA_GRE_TOS]); + + if (!data[IFLA_GRE_PMTUDISC] || nla_get_u8(data[IFLA_GRE_PMTUDISC])) + parms->iph.frag_off = htons(IP_DF); + + if (data[IFLA_GRE_COLLECT_METADATA]) { + struct ip_tunnel *t = netdev_priv(dev); + + t->collect_md = true; + if (dev->type == ARPHRD_IPGRE) + dev->type = ARPHRD_NONE; + } +} + +/* This function returns true when ENCAP attributes are present in the nl msg */ +static bool ipgre_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_GRE_ENCAP_TYPE]) { + ret = true; + ipencap->type = nla_get_u16(data[IFLA_GRE_ENCAP_TYPE]); + } + + if (data[IFLA_GRE_ENCAP_FLAGS]) { + ret = true; + ipencap->flags = nla_get_u16(data[IFLA_GRE_ENCAP_FLAGS]); + } + + if (data[IFLA_GRE_ENCAP_SPORT]) { + ret = true; + ipencap->sport = nla_get_be16(data[IFLA_GRE_ENCAP_SPORT]); + } + + if (data[IFLA_GRE_ENCAP_DPORT]) { + ret = true; + ipencap->dport = nla_get_be16(data[IFLA_GRE_ENCAP_DPORT]); + } + + return ret; +} + +static int gre_tap_init(struct net_device *dev) +{ + __gre_tunnel_init(dev); + dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; + + return ip_tunnel_init(dev); +} + +static const struct net_device_ops gre_tap_netdev_ops = { + .ndo_init = gre_tap_init, + .ndo_uninit = ip_tunnel_uninit, + .ndo_start_xmit = gre_tap_xmit, + .ndo_set_mac_address = eth_mac_addr, + .ndo_validate_addr = eth_validate_addr, + .ndo_change_mtu = ip_tunnel_change_mtu, + .ndo_get_stats64 = ip_tunnel_get_stats64, + .ndo_get_iflink = ip_tunnel_get_iflink, + .ndo_fill_metadata_dst = gre_fill_metadata_dst, +}; + +static void ipgre_tap_setup(struct net_device *dev) +{ + ether_setup(dev); + dev->netdev_ops = &gre_tap_netdev_ops; + dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; + ip_tunnel_setup(dev, gre_tap_net_id); +} + +static int ipgre_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 (ipgre_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; + } + + ipgre_netlink_parms(dev, data, tb, &p); + return ip_tunnel_newlink(dev, tb, &p); +} + +static int ipgre_changelink(struct net_device *dev, struct nlattr *tb[], + struct nlattr *data[]) +{ + struct ip_tunnel_parm p; + struct ip_tunnel_encap ipencap; + + if (ipgre_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; + } + + ipgre_netlink_parms(dev, data, tb, &p); + return ip_tunnel_changelink(dev, tb, &p); +} + +static size_t ipgre_get_size(const struct net_device *dev) +{ + return + /* IFLA_GRE_LINK */ + nla_total_size(4) + + /* IFLA_GRE_IFLAGS */ + nla_total_size(2) + + /* IFLA_GRE_OFLAGS */ + nla_total_size(2) + + /* IFLA_GRE_IKEY */ + nla_total_size(4) + + /* IFLA_GRE_OKEY */ + nla_total_size(4) + + /* IFLA_GRE_LOCAL */ + nla_total_size(4) + + /* IFLA_GRE_REMOTE */ + nla_total_size(4) + + /* IFLA_GRE_TTL */ + nla_total_size(1) + + /* IFLA_GRE_TOS */ + nla_total_size(1) + + /* IFLA_GRE_PMTUDISC */ + nla_total_size(1) + + /* IFLA_GRE_ENCAP_TYPE */ + nla_total_size(2) + + /* IFLA_GRE_ENCAP_FLAGS */ + nla_total_size(2) + + /* IFLA_GRE_ENCAP_SPORT */ + nla_total_size(2) + + /* IFLA_GRE_ENCAP_DPORT */ + nla_total_size(2) + + /* IFLA_GRE_COLLECT_METADATA */ + nla_total_size(0) + + 0; +} + +static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev) +{ + struct ip_tunnel *t = netdev_priv(dev); + struct ip_tunnel_parm *p = &t->parms; + + if (nla_put_u32(skb, IFLA_GRE_LINK, p->link) || + nla_put_be16(skb, IFLA_GRE_IFLAGS, tnl_flags_to_gre_flags(p->i_flags)) || + nla_put_be16(skb, IFLA_GRE_OFLAGS, tnl_flags_to_gre_flags(p->o_flags)) || + nla_put_be32(skb, IFLA_GRE_IKEY, p->i_key) || + nla_put_be32(skb, IFLA_GRE_OKEY, p->o_key) || + nla_put_in_addr(skb, IFLA_GRE_LOCAL, p->iph.saddr) || + nla_put_in_addr(skb, IFLA_GRE_REMOTE, p->iph.daddr) || + nla_put_u8(skb, IFLA_GRE_TTL, p->iph.ttl) || + nla_put_u8(skb, IFLA_GRE_TOS, p->iph.tos) || + nla_put_u8(skb, IFLA_GRE_PMTUDISC, + !!(p->iph.frag_off & htons(IP_DF)))) + goto nla_put_failure; + + if (nla_put_u16(skb, IFLA_GRE_ENCAP_TYPE, + t->encap.type) || + nla_put_be16(skb, IFLA_GRE_ENCAP_SPORT, + t->encap.sport) || + nla_put_be16(skb, IFLA_GRE_ENCAP_DPORT, + t->encap.dport) || + nla_put_u16(skb, IFLA_GRE_ENCAP_FLAGS, + t->encap.flags)) + goto nla_put_failure; + + if (t->collect_md) { + if (nla_put_flag(skb, IFLA_GRE_COLLECT_METADATA)) + goto nla_put_failure; + } + + return 0; + +nla_put_failure: + return -EMSGSIZE; +} + +static const struct nla_policy ipgre_policy[IFLA_GRE_MAX + 1] = { + [IFLA_GRE_LINK] = { .type = NLA_U32 }, + [IFLA_GRE_IFLAGS] = { .type = NLA_U16 }, + [IFLA_GRE_OFLAGS] = { .type = NLA_U16 }, + [IFLA_GRE_IKEY] = { .type = NLA_U32 }, + [IFLA_GRE_OKEY] = { .type = NLA_U32 }, + [IFLA_GRE_LOCAL] = { .len = FIELD_SIZEOF(struct iphdr, saddr) }, + [IFLA_GRE_REMOTE] = { .len = FIELD_SIZEOF(struct iphdr, daddr) }, + [IFLA_GRE_TTL] = { .type = NLA_U8 }, + [IFLA_GRE_TOS] = { .type = NLA_U8 }, + [IFLA_GRE_PMTUDISC] = { .type = NLA_U8 }, + [IFLA_GRE_ENCAP_TYPE] = { .type = NLA_U16 }, + [IFLA_GRE_ENCAP_FLAGS] = { .type = NLA_U16 }, + [IFLA_GRE_ENCAP_SPORT] = { .type = NLA_U16 }, + [IFLA_GRE_ENCAP_DPORT] = { .type = NLA_U16 }, + [IFLA_GRE_COLLECT_METADATA] = { .type = NLA_FLAG }, +}; + +static struct rtnl_link_ops ipgre_link_ops __read_mostly = { + .kind = "gre", + .maxtype = IFLA_GRE_MAX, + .policy = ipgre_policy, + .priv_size = sizeof(struct ip_tunnel), + .setup = ipgre_tunnel_setup, + .validate = ipgre_tunnel_validate, + .newlink = ipgre_newlink, + .changelink = ipgre_changelink, + .dellink = ip_tunnel_dellink, + .get_size = ipgre_get_size, + .fill_info = ipgre_fill_info, + .get_link_net = ip_tunnel_get_link_net, +}; + +static struct rtnl_link_ops ipgre_tap_ops __read_mostly = { + .kind = "gretap", + .maxtype = IFLA_GRE_MAX, + .policy = ipgre_policy, + .priv_size = sizeof(struct ip_tunnel), + .setup = ipgre_tap_setup, + .validate = ipgre_tap_validate, + .newlink = ipgre_newlink, + .changelink = ipgre_changelink, + .dellink = ip_tunnel_dellink, + .get_size = ipgre_get_size, + .fill_info = ipgre_fill_info, + .get_link_net = ip_tunnel_get_link_net, +}; + +struct net_device *gretap_fb_dev_create(struct net *net, const char *name, + u8 name_assign_type) +{ + struct nlattr *tb[IFLA_MAX + 1]; + struct net_device *dev; + LIST_HEAD(list_kill); + struct ip_tunnel *t; + int err; + + memset(&tb, 0, sizeof(tb)); + + dev = rtnl_create_link(net, name, name_assign_type, + &ipgre_tap_ops, tb); + if (IS_ERR(dev)) + return dev; + + /* Configure flow based GRE device. */ + t = netdev_priv(dev); + t->collect_md = true; + + err = ipgre_newlink(net, dev, tb, NULL); + if (err < 0) { + free_netdev(dev); + return ERR_PTR(err); + } + + /* openvswitch users expect packet sizes to be unrestricted, + * so set the largest MTU we can. + */ + err = __ip_tunnel_change_mtu(dev, IP_MAX_MTU, false); + if (err) + goto out; + + err = rtnl_configure_link(dev, NULL); + if (err < 0) + goto out; + + return dev; +out: + ip_tunnel_dellink(dev, &list_kill); + unregister_netdevice_many(&list_kill); + return ERR_PTR(err); +} +EXPORT_SYMBOL_GPL(gretap_fb_dev_create); + +static int __net_init ipgre_tap_init_net(struct net *net) +{ + return ip_tunnel_init_net(net, gre_tap_net_id, &ipgre_tap_ops, "gretap0"); +} + +static void __net_exit ipgre_tap_exit_net(struct net *net) +{ + struct ip_tunnel_net *itn = net_generic(net, gre_tap_net_id); + ip_tunnel_delete_net(itn, &ipgre_tap_ops); +} + +static struct pernet_operations ipgre_tap_net_ops = { + .init = ipgre_tap_init_net, + .exit = ipgre_tap_exit_net, + .id = &gre_tap_net_id, + .size = sizeof(struct ip_tunnel_net), +}; + +static int __init ipgre_init(void) +{ + int err; + + pr_info("GRE over IPv4 tunneling driver\n"); + + err = register_pernet_device(&ipgre_net_ops); + if (err < 0) + return err; + + err = register_pernet_device(&ipgre_tap_net_ops); + if (err < 0) + goto pnet_tap_faied; + + err = gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO); + if (err < 0) { + pr_info("%s: can't add protocol\n", __func__); + goto add_proto_failed; + } + + err = rtnl_link_register(&ipgre_link_ops); + if (err < 0) + goto rtnl_link_failed; + + err = rtnl_link_register(&ipgre_tap_ops); + if (err < 0) + goto tap_ops_failed; + + return 0; + +tap_ops_failed: + rtnl_link_unregister(&ipgre_link_ops); +rtnl_link_failed: + gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO); +add_proto_failed: + unregister_pernet_device(&ipgre_tap_net_ops); +pnet_tap_faied: + unregister_pernet_device(&ipgre_net_ops); + return err; +} + +static void __exit ipgre_fini(void) +{ + rtnl_link_unregister(&ipgre_tap_ops); + rtnl_link_unregister(&ipgre_link_ops); + gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO); + unregister_pernet_device(&ipgre_tap_net_ops); + unregister_pernet_device(&ipgre_net_ops); +} + +module_init(ipgre_init); +module_exit(ipgre_fini); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_RTNL_LINK("gre"); +MODULE_ALIAS_RTNL_LINK("gretap"); +MODULE_ALIAS_NETDEV("gre0"); +MODULE_ALIAS_NETDEV("gretap0"); |