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ip6_tun: Add infrastructure for doing encapsulation
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Add encap_hlen and ip_tunnel_encap structure to ip6_tnl. Add functions
for getting encap hlen, setting up encap on a tunnel, performing
encapsulation operation.

Signed-off-by: Tom Herbert <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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@tomratbert @davem330
tomratbert authored and davem330 committed May 20, 2016
1 parent 5f914b6 commit 058214a
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Showing 3 changed files with 144 additions and 13 deletions.
58 changes: 58 additions & 0 deletions include/net/ip6_tunnel.h
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Original file line number Diff line number Diff line change
Expand Up @@ -52,10 +52,68 @@ struct ip6_tnl {
__u32 o_seqno; /* The last output seqno */
int hlen; /* tun_hlen + encap_hlen */
int tun_hlen; /* Precalculated header length */
int encap_hlen; /* Encap header length (FOU,GUE) */
struct ip_tunnel_encap encap;
int mlink;
};

struct ip6_tnl_encap_ops {
size_t (*encap_hlen)(struct ip_tunnel_encap *e);
int (*build_header)(struct sk_buff *skb, struct ip_tunnel_encap *e,
u8 *protocol, struct flowi6 *fl6);
};

extern const struct ip6_tnl_encap_ops __rcu *
ip6tun_encaps[MAX_IPTUN_ENCAP_OPS];

int ip6_tnl_encap_add_ops(const struct ip6_tnl_encap_ops *ops,
unsigned int num);
int ip6_tnl_encap_del_ops(const struct ip6_tnl_encap_ops *ops,
unsigned int num);
int ip6_tnl_encap_setup(struct ip6_tnl *t,
struct ip_tunnel_encap *ipencap);

static inline int ip6_encap_hlen(struct ip_tunnel_encap *e)
{
const struct ip6_tnl_encap_ops *ops;
int hlen = -EINVAL;

if (e->type == TUNNEL_ENCAP_NONE)
return 0;

if (e->type >= MAX_IPTUN_ENCAP_OPS)
return -EINVAL;

rcu_read_lock();
ops = rcu_dereference(ip6tun_encaps[e->type]);
if (likely(ops && ops->encap_hlen))
hlen = ops->encap_hlen(e);
rcu_read_unlock();

return hlen;
}

static inline int ip6_tnl_encap(struct sk_buff *skb, struct ip6_tnl *t,
u8 *protocol, struct flowi6 *fl6)
{
const struct ip6_tnl_encap_ops *ops;
int ret = -EINVAL;

if (t->encap.type == TUNNEL_ENCAP_NONE)
return 0;

if (t->encap.type >= MAX_IPTUN_ENCAP_OPS)
return -EINVAL;

rcu_read_lock();
ops = rcu_dereference(ip6tun_encaps[t->encap.type]);
if (likely(ops && ops->build_header))
ret = ops->build_header(skb, &t->encap, protocol, fl6);
rcu_read_unlock();

return ret;
}

/* Tunnel encapsulation limit destination sub-option */

struct ipv6_tlv_tnl_enc_lim {
Expand Down
5 changes: 5 additions & 0 deletions net/ipv4/ip_tunnel_core.c
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Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,7 @@
#include <net/icmp.h>
#include <net/protocol.h>
#include <net/ip_tunnels.h>
#include <net/ip6_tunnel.h>
#include <net/arp.h>
#include <net/checksum.h>
#include <net/dsfield.h>
Expand All @@ -51,6 +52,10 @@ const struct ip_tunnel_encap_ops __rcu *
iptun_encaps[MAX_IPTUN_ENCAP_OPS] __read_mostly;
EXPORT_SYMBOL(iptun_encaps);

const struct ip6_tnl_encap_ops __rcu *
ip6tun_encaps[MAX_IPTUN_ENCAP_OPS] __read_mostly;
EXPORT_SYMBOL(ip6tun_encaps);

void iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
__be32 src, __be32 dst, __u8 proto,
__u8 tos, __u8 ttl, __be16 df, bool xnet)
Expand Down
94 changes: 81 additions & 13 deletions net/ipv6/ip6_tunnel.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1010,7 +1010,8 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield,
struct dst_entry *dst = NULL, *ndst = NULL;
struct net_device *tdev;
int mtu;
unsigned int max_headroom = sizeof(struct ipv6hdr);
unsigned int psh_hlen = sizeof(struct ipv6hdr) + t->encap_hlen;
unsigned int max_headroom = psh_hlen;
int err = -1;

/* NBMA tunnel */
Expand Down Expand Up @@ -1063,7 +1064,7 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield,
t->parms.name);
goto tx_err_dst_release;
}
mtu = dst_mtu(dst) - sizeof(*ipv6h);
mtu = dst_mtu(dst) - psh_hlen;
if (encap_limit >= 0) {
max_headroom += 8;
mtu -= 8;
Expand Down Expand Up @@ -1124,11 +1125,18 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield,
skb->encapsulation = 1;
}

/* Calculate max headroom for all the headers and adjust
* needed_headroom if necessary.
*/
max_headroom = LL_RESERVED_SPACE(dst->dev) + sizeof(struct ipv6hdr)
+ dst->header_len;
+ dst->header_len + t->hlen;
if (max_headroom > dev->needed_headroom)
dev->needed_headroom = max_headroom;

err = ip6_tnl_encap(skb, t, &proto, fl6);
if (err)
return err;

skb_push(skb, sizeof(struct ipv6hdr));
skb_reset_network_header(skb);
ipv6h = ipv6_hdr(skb);
Expand Down Expand Up @@ -1280,6 +1288,7 @@ 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;
int t_hlen;

memcpy(dev->dev_addr, &p->laddr, sizeof(struct in6_addr));
memcpy(dev->broadcast, &p->raddr, sizeof(struct in6_addr));
Expand All @@ -1303,6 +1312,10 @@ static void ip6_tnl_link_config(struct ip6_tnl *t)
else
dev->flags &= ~IFF_POINTOPOINT;

t->tun_hlen = 0;
t->hlen = t->encap_hlen + t->tun_hlen;
t_hlen = t->hlen + sizeof(struct ipv6hdr);

if (p->flags & IP6_TNL_F_CAP_XMIT) {
int strict = (ipv6_addr_type(&p->raddr) &
(IPV6_ADDR_MULTICAST|IPV6_ADDR_LINKLOCAL));
Expand All @@ -1316,9 +1329,9 @@ static void ip6_tnl_link_config(struct ip6_tnl *t)

if (rt->dst.dev) {
dev->hard_header_len = rt->dst.dev->hard_header_len +
sizeof(struct ipv6hdr);
t_hlen;

dev->mtu = rt->dst.dev->mtu - sizeof(struct ipv6hdr);
dev->mtu = rt->dst.dev->mtu - t_hlen;
if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
dev->mtu -= 8;

Expand Down Expand Up @@ -1564,6 +1577,59 @@ int ip6_tnl_get_iflink(const struct net_device *dev)
}
EXPORT_SYMBOL(ip6_tnl_get_iflink);

int ip6_tnl_encap_add_ops(const struct ip6_tnl_encap_ops *ops,
unsigned int num)
{
if (num >= MAX_IPTUN_ENCAP_OPS)
return -ERANGE;

return !cmpxchg((const struct ip6_tnl_encap_ops **)
&ip6tun_encaps[num],
NULL, ops) ? 0 : -1;
}
EXPORT_SYMBOL(ip6_tnl_encap_add_ops);

int ip6_tnl_encap_del_ops(const struct ip6_tnl_encap_ops *ops,
unsigned int num)
{
int ret;

if (num >= MAX_IPTUN_ENCAP_OPS)
return -ERANGE;

ret = (cmpxchg((const struct ip6_tnl_encap_ops **)
&ip6tun_encaps[num],
ops, NULL) == ops) ? 0 : -1;

synchronize_net();

return ret;
}
EXPORT_SYMBOL(ip6_tnl_encap_del_ops);

int ip6_tnl_encap_setup(struct ip6_tnl *t,
struct ip_tunnel_encap *ipencap)
{
int hlen;

memset(&t->encap, 0, sizeof(t->encap));

hlen = ip6_encap_hlen(ipencap);
if (hlen < 0)
return hlen;

t->encap.type = ipencap->type;
t->encap.sport = ipencap->sport;
t->encap.dport = ipencap->dport;
t->encap.flags = ipencap->flags;

t->encap_hlen = hlen;
t->hlen = t->encap_hlen + t->tun_hlen;

return 0;
}
EXPORT_SYMBOL_GPL(ip6_tnl_encap_setup);

static const struct net_device_ops ip6_tnl_netdev_ops = {
.ndo_init = ip6_tnl_dev_init,
.ndo_uninit = ip6_tnl_dev_uninit,
Expand All @@ -1585,19 +1651,13 @@ static const struct net_device_ops ip6_tnl_netdev_ops = {

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_LLTX;
netif_keep_dst(dev);
/* This perm addr will be used as interface identifier by IPv6 */
dev->addr_assign_type = NET_ADDR_RANDOM;
Expand All @@ -1615,6 +1675,7 @@ ip6_tnl_dev_init_gen(struct net_device *dev)
{
struct ip6_tnl *t = netdev_priv(dev);
int ret;
int t_hlen;

t->dev = dev;
t->net = dev_net(dev);
Expand All @@ -1630,8 +1691,15 @@ ip6_tnl_dev_init_gen(struct net_device *dev)
if (ret)
goto destroy_dst;

t->hlen = 0;
t->tun_hlen = 0;
t->hlen = t->encap_hlen + t->tun_hlen;
t_hlen = t->hlen + sizeof(struct ipv6hdr);

dev->type = ARPHRD_TUNNEL6;
dev->hard_header_len = LL_MAX_HEADER + t_hlen;
dev->mtu = ETH_DATA_LEN - t_hlen;
if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
dev->mtu -= 8;

return 0;

Expand Down

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