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ip_tunnel: add collect_md mode to IPIP tunnel
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Similar to gre, vxlan, geneve tunnels allow IPIP tunnels to
operate in 'collect metadata' mode.
bpf_skb_[gs]et_tunnel_key() helpers can make use of it right away.
ovs can use it as well in the future (once appropriate ovs-vport
abstractions and user apis are added).
Note that just like in other tunnels we cannot cache the dst,
since tunnel_info metadata can be different for every packet.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Alexei Starovoitov authored and David S. Miller committed Sep 17, 2016
1 parent eb94737 commit cfc7381
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Showing 4 changed files with 108 additions and 6 deletions.
2 changes: 2 additions & 0 deletions include/net/ip_tunnels.h
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Original file line number Diff line number Diff line change
Expand Up @@ -255,6 +255,8 @@ void ip_tunnel_delete_net(struct ip_tunnel_net *itn, struct rtnl_link_ops *ops);

void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
const struct iphdr *tnl_params, const u8 protocol);
void ip_md_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
const u8 proto);
int ip_tunnel_ioctl(struct net_device *dev, struct ip_tunnel_parm *p, int cmd);
int __ip_tunnel_change_mtu(struct net_device *dev, int new_mtu, bool strict);
int ip_tunnel_change_mtu(struct net_device *dev, int new_mtu);
Expand Down
1 change: 1 addition & 0 deletions include/uapi/linux/if_tunnel.h
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Original file line number Diff line number Diff line change
Expand Up @@ -73,6 +73,7 @@ enum {
IFLA_IPTUN_ENCAP_FLAGS,
IFLA_IPTUN_ENCAP_SPORT,
IFLA_IPTUN_ENCAP_DPORT,
IFLA_IPTUN_COLLECT_METADATA,
__IFLA_IPTUN_MAX,
};
#define IFLA_IPTUN_MAX (__IFLA_IPTUN_MAX - 1)
Expand Down
76 changes: 76 additions & 0 deletions net/ipv4/ip_tunnel.c
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Original file line number Diff line number Diff line change
Expand Up @@ -55,6 +55,7 @@
#include <net/netns/generic.h>
#include <net/rtnetlink.h>
#include <net/udp.h>
#include <net/dst_metadata.h>

#if IS_ENABLED(CONFIG_IPV6)
#include <net/ipv6.h>
Expand Down Expand Up @@ -546,6 +547,81 @@ static int tnl_update_pmtu(struct net_device *dev, struct sk_buff *skb,
return 0;
}

void ip_md_tunnel_xmit(struct sk_buff *skb, struct net_device *dev, u8 proto)
{
struct ip_tunnel *tunnel = netdev_priv(dev);
u32 headroom = sizeof(struct iphdr);
struct ip_tunnel_info *tun_info;
const struct ip_tunnel_key *key;
const struct iphdr *inner_iph;
struct rtable *rt;
struct flowi4 fl4;
__be16 df = 0;
u8 tos, ttl;

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 tx_error;
key = &tun_info->key;
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
inner_iph = (const struct iphdr *)skb_inner_network_header(skb);
tos = key->tos;
if (tos == 1) {
if (skb->protocol == htons(ETH_P_IP))
tos = inner_iph->tos;
else if (skb->protocol == htons(ETH_P_IPV6))
tos = ipv6_get_dsfield((const struct ipv6hdr *)inner_iph);
}
init_tunnel_flow(&fl4, proto, key->u.ipv4.dst, key->u.ipv4.src, 0,
RT_TOS(tos), tunnel->parms.link);
if (tunnel->encap.type != TUNNEL_ENCAP_NONE)
goto tx_error;
rt = ip_route_output_key(tunnel->net, &fl4);
if (IS_ERR(rt)) {
dev->stats.tx_carrier_errors++;
goto tx_error;
}
if (rt->dst.dev == dev) {
ip_rt_put(rt);
dev->stats.collisions++;
goto tx_error;
}
tos = ip_tunnel_ecn_encap(tos, inner_iph, skb);
ttl = key->ttl;
if (ttl == 0) {
if (skb->protocol == htons(ETH_P_IP))
ttl = inner_iph->ttl;
else if (skb->protocol == htons(ETH_P_IPV6))
ttl = ((const struct ipv6hdr *)inner_iph)->hop_limit;
else
ttl = ip4_dst_hoplimit(&rt->dst);
}
if (key->tun_flags & TUNNEL_DONT_FRAGMENT)
df = htons(IP_DF);
else if (skb->protocol == htons(ETH_P_IP))
df = inner_iph->frag_off & htons(IP_DF);
headroom += LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len;
if (headroom > dev->needed_headroom)
dev->needed_headroom = headroom;

if (skb_cow_head(skb, dev->needed_headroom)) {
ip_rt_put(rt);
goto tx_dropped;
}
iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, proto, key->tos,
key->ttl, df, !net_eq(tunnel->net, dev_net(dev)));
return;
tx_error:
dev->stats.tx_errors++;
goto kfree;
tx_dropped:
dev->stats.tx_dropped++;
kfree:
kfree_skb(skb);
}
EXPORT_SYMBOL_GPL(ip_md_tunnel_xmit);

void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
const struct iphdr *tnl_params, u8 protocol)
{
Expand Down
35 changes: 29 additions & 6 deletions net/ipv4/ipip.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -115,6 +115,7 @@
#include <net/xfrm.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <net/dst_metadata.h>

static bool log_ecn_error = true;
module_param(log_ecn_error, bool, 0644);
Expand Down Expand Up @@ -193,6 +194,7 @@ static int ipip_tunnel_rcv(struct sk_buff *skb, u8 ipproto)
{
struct net *net = dev_net(skb->dev);
struct ip_tunnel_net *itn = net_generic(net, ipip_net_id);
struct metadata_dst *tun_dst = NULL;
struct ip_tunnel *tunnel;
const struct iphdr *iph;

Expand All @@ -216,7 +218,12 @@ static int ipip_tunnel_rcv(struct sk_buff *skb, u8 ipproto)
tpi = &ipip_tpi;
if (iptunnel_pull_header(skb, 0, tpi->proto, false))
goto drop;
return ip_tunnel_rcv(tunnel, skb, tpi, NULL, log_ecn_error);
if (tunnel->collect_md) {
tun_dst = ip_tun_rx_dst(skb, 0, 0, 0);
if (!tun_dst)
return 0;
}
return ip_tunnel_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error);
}

return -1;
Expand Down Expand Up @@ -270,7 +277,10 @@ static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb,

skb_set_inner_ipproto(skb, ipproto);

ip_tunnel_xmit(skb, dev, tiph, ipproto);
if (tunnel->collect_md)
ip_md_tunnel_xmit(skb, dev, ipproto);
else
ip_tunnel_xmit(skb, dev, tiph, ipproto);
return NETDEV_TX_OK;

tx_error:
Expand Down Expand Up @@ -380,13 +390,14 @@ static int ipip_tunnel_validate(struct nlattr *tb[], struct nlattr *data[])
}

static void ipip_netlink_parms(struct nlattr *data[],
struct ip_tunnel_parm *parms)
struct ip_tunnel_parm *parms, bool *collect_md)
{
memset(parms, 0, sizeof(*parms));

parms->iph.version = 4;
parms->iph.protocol = IPPROTO_IPIP;
parms->iph.ihl = 5;
*collect_md = false;

if (!data)
return;
Expand Down Expand Up @@ -414,6 +425,9 @@ static void ipip_netlink_parms(struct nlattr *data[],

if (!data[IFLA_IPTUN_PMTUDISC] || nla_get_u8(data[IFLA_IPTUN_PMTUDISC]))
parms->iph.frag_off = htons(IP_DF);

if (data[IFLA_IPTUN_COLLECT_METADATA])
*collect_md = true;
}

/* This function returns true when ENCAP attributes are present in the nl msg */
Expand Down Expand Up @@ -453,18 +467,18 @@ static bool ipip_netlink_encap_parms(struct nlattr *data[],
static int ipip_newlink(struct net *src_net, struct net_device *dev,
struct nlattr *tb[], struct nlattr *data[])
{
struct ip_tunnel *t = netdev_priv(dev);
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);
ipip_netlink_parms(data, &p, &t->collect_md);
return ip_tunnel_newlink(dev, tb, &p);
}

Expand All @@ -473,6 +487,7 @@ static int ipip_changelink(struct net_device *dev, struct nlattr *tb[],
{
struct ip_tunnel_parm p;
struct ip_tunnel_encap ipencap;
bool collect_md;

if (ipip_netlink_encap_parms(data, &ipencap)) {
struct ip_tunnel *t = netdev_priv(dev);
Expand All @@ -482,7 +497,9 @@ static int ipip_changelink(struct net_device *dev, struct nlattr *tb[],
return err;
}

ipip_netlink_parms(data, &p);
ipip_netlink_parms(data, &p, &collect_md);
if (collect_md)
return -EINVAL;

if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) ||
(!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr))
Expand Down Expand Up @@ -516,6 +533,8 @@ static size_t ipip_get_size(const struct net_device *dev)
nla_total_size(2) +
/* IFLA_IPTUN_ENCAP_DPORT */
nla_total_size(2) +
/* IFLA_IPTUN_COLLECT_METADATA */
nla_total_size(0) +
0;
}

Expand Down Expand Up @@ -544,6 +563,9 @@ static int ipip_fill_info(struct sk_buff *skb, const struct net_device *dev)
tunnel->encap.flags))
goto nla_put_failure;

if (tunnel->collect_md)
if (nla_put_flag(skb, IFLA_IPTUN_COLLECT_METADATA))
goto nla_put_failure;
return 0;

nla_put_failure:
Expand All @@ -562,6 +584,7 @@ static const struct nla_policy ipip_policy[IFLA_IPTUN_MAX + 1] = {
[IFLA_IPTUN_ENCAP_FLAGS] = { .type = NLA_U16 },
[IFLA_IPTUN_ENCAP_SPORT] = { .type = NLA_U16 },
[IFLA_IPTUN_ENCAP_DPORT] = { .type = NLA_U16 },
[IFLA_IPTUN_COLLECT_METADATA] = { .type = NLA_FLAG },
};

static struct rtnl_link_ops ipip_link_ops __read_mostly = {
Expand Down

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