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gre: Setup and TX path for gre/UDP foo-over-udp encapsulation
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Added netlink attrs to configure FOU encapsulation for GRE, netlink
handling of these flags, and properly adjust MTU for encapsulation.
ip_tunnel_encap is called from ip_tunnel_xmit to actually perform FOU
encapsulation.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Tom Herbert authored and David S. Miller committed Sep 19, 2014
1 parent 473ab82 commit 4565e99
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Showing 2 changed files with 89 additions and 5 deletions.
4 changes: 4 additions & 0 deletions include/uapi/linux/if_tunnel.h
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Original file line number Diff line number Diff line change
Expand Up @@ -106,6 +106,10 @@ enum {
IFLA_GRE_ENCAP_LIMIT,
IFLA_GRE_FLOWINFO,
IFLA_GRE_FLAGS,
IFLA_GRE_ENCAP_TYPE,
IFLA_GRE_ENCAP_FLAGS,
IFLA_GRE_ENCAP_SPORT,
IFLA_GRE_ENCAP_DPORT,
__IFLA_GRE_MAX,
};

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90 changes: 85 additions & 5 deletions net/ipv4/ip_gre.c
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Original file line number Diff line number Diff line change
Expand Up @@ -239,7 +239,7 @@ static void __gre_xmit(struct sk_buff *skb, struct net_device *dev,
tpi.seq = htonl(tunnel->o_seqno);

/* Push GRE header. */
gre_build_header(skb, &tpi, tunnel->hlen);
gre_build_header(skb, &tpi, tunnel->tun_hlen);

ip_tunnel_xmit(skb, dev, tnl_params, tnl_params->protocol);
}
Expand Down Expand Up @@ -310,7 +310,7 @@ static netdev_tx_t gre_tap_xmit(struct sk_buff *skb,
static int ipgre_tunnel_ioctl(struct net_device *dev,
struct ifreq *ifr, int cmd)
{
int err = 0;
int err;
struct ip_tunnel_parm p;

if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
Expand Down Expand Up @@ -470,13 +470,18 @@ static void ipgre_tunnel_setup(struct net_device *dev)
static void __gre_tunnel_init(struct net_device *dev)
{
struct ip_tunnel *tunnel;
int t_hlen;

tunnel = netdev_priv(dev);
tunnel->hlen = ip_gre_calc_hlen(tunnel->parms.o_flags);
tunnel->tun_hlen = ip_gre_calc_hlen(tunnel->parms.o_flags);
tunnel->parms.iph.protocol = IPPROTO_GRE;

dev->needed_headroom = LL_MAX_HEADER + sizeof(struct iphdr) + 4;
dev->mtu = ETH_DATA_LEN - sizeof(struct iphdr) - 4;
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;
Expand Down Expand Up @@ -628,6 +633,40 @@ static void ipgre_netlink_parms(struct nlattr *data[], struct nlattr *tb[],
parms->iph.frag_off = htons(IP_DF);
}

/* 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_u16(data[IFLA_GRE_ENCAP_SPORT]);
}

if (data[IFLA_GRE_ENCAP_DPORT]) {
ret = true;
ipencap->dport = nla_get_u16(data[IFLA_GRE_ENCAP_DPORT]);
}

return ret;
}

static int gre_tap_init(struct net_device *dev)
{
__gre_tunnel_init(dev);
Expand Down Expand Up @@ -657,6 +696,15 @@ 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(data, tb, &p);
return ip_tunnel_newlink(dev, tb, &p);
Expand All @@ -666,6 +714,15 @@ 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(data, tb, &p);
return ip_tunnel_changelink(dev, tb, &p);
Expand Down Expand Up @@ -694,6 +751,14 @@ static size_t ipgre_get_size(const struct net_device *dev)
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) +
0;
}

Expand All @@ -714,6 +779,17 @@ static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)
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_u16(skb, IFLA_GRE_ENCAP_SPORT,
t->encap.sport) ||
nla_put_u16(skb, IFLA_GRE_ENCAP_DPORT,
t->encap.dport) ||
nla_put_u16(skb, IFLA_GRE_ENCAP_FLAGS,
t->encap.dport))
goto nla_put_failure;

return 0;

nla_put_failure:
Expand All @@ -731,6 +807,10 @@ static const struct nla_policy ipgre_policy[IFLA_GRE_MAX + 1] = {
[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 },
};

static struct rtnl_link_ops ipgre_link_ops __read_mostly = {
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