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ip6_tunnel: add collect_md mode to IPv6 tunnels
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Similar to gre, vxlan, geneve tunnels allow IPIP6 and IP6IP6 tunnels
to operate in 'collect metadata' mode.
Unlike ipv4 code here it's possible to reuse ip6_tnl_xmit() function
for both collect_md and traditional tunnels.
bpf_skb_[gs]et_tunnel_key() helpers and ovs (in the future) are the users.

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 cfc7381 commit 8d79266
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Showing 2 changed files with 134 additions and 45 deletions.
1 change: 1 addition & 0 deletions include/net/ip6_tunnel.h
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@ struct __ip6_tnl_parm {
__u8 proto; /* tunnel protocol */
__u8 encap_limit; /* encapsulation limit for tunnel */
__u8 hop_limit; /* hop limit for tunnel */
bool collect_md;
__be32 flowinfo; /* traffic class and flowlabel for tunnel */
__u32 flags; /* tunnel flags */
struct in6_addr laddr; /* local tunnel end-point address */
Expand Down
178 changes: 133 additions & 45 deletions net/ipv6/ip6_tunnel.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -57,6 +57,7 @@
#include <net/inet_ecn.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <net/dst_metadata.h>

MODULE_AUTHOR("Ville Nuorvala");
MODULE_DESCRIPTION("IPv6 tunneling device");
Expand Down Expand Up @@ -90,6 +91,7 @@ struct ip6_tnl_net {
struct ip6_tnl __rcu *tnls_r_l[IP6_TUNNEL_HASH_SIZE];
struct ip6_tnl __rcu *tnls_wc[1];
struct ip6_tnl __rcu **tnls[2];
struct ip6_tnl __rcu *collect_md_tun;
};

static struct net_device_stats *ip6_get_stats(struct net_device *dev)
Expand Down Expand Up @@ -166,6 +168,10 @@ ip6_tnl_lookup(struct net *net, const struct in6_addr *remote, const struct in6_
return t;
}

t = rcu_dereference(ip6n->collect_md_tun);
if (t)
return t;

t = rcu_dereference(ip6n->tnls_wc[0]);
if (t && (t->dev->flags & IFF_UP))
return t;
Expand Down Expand Up @@ -209,6 +215,8 @@ ip6_tnl_link(struct ip6_tnl_net *ip6n, struct ip6_tnl *t)
{
struct ip6_tnl __rcu **tp = ip6_tnl_bucket(ip6n, &t->parms);

if (t->parms.collect_md)
rcu_assign_pointer(ip6n->collect_md_tun, t);
rcu_assign_pointer(t->next , rtnl_dereference(*tp));
rcu_assign_pointer(*tp, t);
}
Expand All @@ -224,6 +232,9 @@ ip6_tnl_unlink(struct ip6_tnl_net *ip6n, struct ip6_tnl *t)
struct ip6_tnl __rcu **tp;
struct ip6_tnl *iter;

if (t->parms.collect_md)
rcu_assign_pointer(ip6n->collect_md_tun, NULL);

for (tp = ip6_tnl_bucket(ip6n, &t->parms);
(iter = rtnl_dereference(*tp)) != NULL;
tp = &iter->next) {
Expand Down Expand Up @@ -829,6 +840,9 @@ static int __ip6_tnl_rcv(struct ip6_tnl *tunnel, struct sk_buff *skb,

skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(tunnel->dev)));

if (tun_dst)
skb_dst_set(skb, (struct dst_entry *)tun_dst);

gro_cells_receive(&tunnel->gro_cells, skb);
return 0;

Expand Down Expand Up @@ -865,6 +879,7 @@ static int ipxip6_rcv(struct sk_buff *skb, u8 ipproto,
{
struct ip6_tnl *t;
const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
struct metadata_dst *tun_dst = NULL;
int ret = -1;

rcu_read_lock();
Expand All @@ -881,7 +896,12 @@ static int ipxip6_rcv(struct sk_buff *skb, u8 ipproto,
goto drop;
if (iptunnel_pull_header(skb, 0, tpi->proto, false))
goto drop;
ret = __ip6_tnl_rcv(t, skb, tpi, NULL, dscp_ecn_decapsulate,
if (t->parms.collect_md) {
tun_dst = ipv6_tun_rx_dst(skb, 0, 0, 0);
if (!tun_dst)
return 0;
}
ret = __ip6_tnl_rcv(t, skb, tpi, tun_dst, dscp_ecn_decapsulate,
log_ecn_error);
}

Expand Down Expand Up @@ -1012,8 +1032,16 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield,
int mtu;
unsigned int psh_hlen = sizeof(struct ipv6hdr) + t->encap_hlen;
unsigned int max_headroom = psh_hlen;
u8 hop_limit;
int err = -1;

if (t->parms.collect_md) {
hop_limit = skb_tunnel_info(skb)->key.ttl;
goto route_lookup;
} else {
hop_limit = t->parms.hop_limit;
}

/* NBMA tunnel */
if (ipv6_addr_any(&t->parms.raddr)) {
struct in6_addr *addr6;
Expand Down Expand Up @@ -1043,6 +1071,7 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield,
goto tx_err_link_failure;

if (!dst) {
route_lookup:
dst = ip6_route_output(net, NULL, fl6);

if (dst->error)
Expand All @@ -1053,6 +1082,10 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield,
dst = NULL;
goto tx_err_link_failure;
}
if (t->parms.collect_md &&
ipv6_dev_get_saddr(net, ip6_dst_idev(dst)->dev,
&fl6->daddr, 0, &fl6->saddr))
goto tx_err_link_failure;
ndst = dst;
}

Expand All @@ -1071,7 +1104,7 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield,
}
if (mtu < IPV6_MIN_MTU)
mtu = IPV6_MIN_MTU;
if (skb_dst(skb))
if (skb_dst(skb) && !t->parms.collect_md)
skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
if (skb->len > mtu && !skb_is_gso(skb)) {
*pmtu = mtu;
Expand Down Expand Up @@ -1111,8 +1144,13 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield,
skb = new_skb;
}

if (!fl6->flowi6_mark && ndst)
dst_cache_set_ip6(&t->dst_cache, ndst, &fl6->saddr);
if (t->parms.collect_md) {
if (t->encap.type != TUNNEL_ENCAP_NONE)
goto tx_err_dst_release;
} else {
if (!fl6->flowi6_mark && ndst)
dst_cache_set_ip6(&t->dst_cache, ndst, &fl6->saddr);
}
skb_dst_set(skb, dst);

if (encap_limit >= 0) {
Expand All @@ -1137,7 +1175,7 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield,
ipv6h = ipv6_hdr(skb);
ip6_flow_hdr(ipv6h, INET_ECN_encapsulate(0, dsfield),
ip6_make_flowlabel(net, skb, fl6->flowlabel, true, fl6));
ipv6h->hop_limit = t->parms.hop_limit;
ipv6h->hop_limit = hop_limit;
ipv6h->nexthdr = proto;
ipv6h->saddr = fl6->saddr;
ipv6h->daddr = fl6->daddr;
Expand Down Expand Up @@ -1170,19 +1208,34 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
if (tproto != IPPROTO_IPIP && tproto != 0)
return -1;

if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
encap_limit = t->parms.encap_limit;
dsfield = ipv4_get_dsfield(iph);

memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));
fl6.flowi6_proto = IPPROTO_IPIP;
if (t->parms.collect_md) {
struct ip_tunnel_info *tun_info;
const struct ip_tunnel_key *key;

dsfield = ipv4_get_dsfield(iph);
tun_info = skb_tunnel_info(skb);
if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) ||
ip_tunnel_info_af(tun_info) != AF_INET6))
return -1;
key = &tun_info->key;
memset(&fl6, 0, sizeof(fl6));
fl6.flowi6_proto = IPPROTO_IPIP;
fl6.daddr = key->u.ipv6.dst;
fl6.flowlabel = key->label;
} else {
if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
encap_limit = t->parms.encap_limit;

if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)
fl6.flowlabel |= htonl((__u32)iph->tos << IPV6_TCLASS_SHIFT)
& IPV6_TCLASS_MASK;
if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
fl6.flowi6_mark = skb->mark;
memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));
fl6.flowi6_proto = IPPROTO_IPIP;

if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)
fl6.flowlabel |= htonl((__u32)iph->tos << IPV6_TCLASS_SHIFT)
& IPV6_TCLASS_MASK;
if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
fl6.flowi6_mark = skb->mark;
}

if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP6))
return -1;
Expand Down Expand Up @@ -1220,29 +1273,47 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
ip6_tnl_addr_conflict(t, ipv6h))
return -1;

offset = ip6_tnl_parse_tlv_enc_lim(skb, skb_network_header(skb));
if (offset > 0) {
struct ipv6_tlv_tnl_enc_lim *tel;
tel = (struct ipv6_tlv_tnl_enc_lim *)&skb_network_header(skb)[offset];
if (tel->encap_limit == 0) {
icmpv6_send(skb, ICMPV6_PARAMPROB,
ICMPV6_HDR_FIELD, offset + 2);
dsfield = ipv6_get_dsfield(ipv6h);

if (t->parms.collect_md) {
struct ip_tunnel_info *tun_info;
const struct ip_tunnel_key *key;

tun_info = skb_tunnel_info(skb);
if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) ||
ip_tunnel_info_af(tun_info) != AF_INET6))
return -1;
key = &tun_info->key;
memset(&fl6, 0, sizeof(fl6));
fl6.flowi6_proto = IPPROTO_IPV6;
fl6.daddr = key->u.ipv6.dst;
fl6.flowlabel = key->label;
} else {
offset = ip6_tnl_parse_tlv_enc_lim(skb, skb_network_header(skb));
if (offset > 0) {
struct ipv6_tlv_tnl_enc_lim *tel;

tel = (void *)&skb_network_header(skb)[offset];
if (tel->encap_limit == 0) {
icmpv6_send(skb, ICMPV6_PARAMPROB,
ICMPV6_HDR_FIELD, offset + 2);
return -1;
}
encap_limit = tel->encap_limit - 1;
} else if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT)) {
encap_limit = t->parms.encap_limit;
}
encap_limit = tel->encap_limit - 1;
} else if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
encap_limit = t->parms.encap_limit;

memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));
fl6.flowi6_proto = IPPROTO_IPV6;
memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));
fl6.flowi6_proto = IPPROTO_IPV6;

dsfield = ipv6_get_dsfield(ipv6h);
if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)
fl6.flowlabel |= (*(__be32 *) ipv6h & IPV6_TCLASS_MASK);
if (t->parms.flags & IP6_TNL_F_USE_ORIG_FLOWLABEL)
fl6.flowlabel |= ip6_flowlabel(ipv6h);
if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
fl6.flowi6_mark = skb->mark;
if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)
fl6.flowlabel |= (*(__be32 *)ipv6h & IPV6_TCLASS_MASK);
if (t->parms.flags & IP6_TNL_F_USE_ORIG_FLOWLABEL)
fl6.flowlabel |= ip6_flowlabel(ipv6h);
if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
fl6.flowi6_mark = skb->mark;
}

if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP6))
return -1;
Expand Down Expand Up @@ -1741,6 +1812,10 @@ static int ip6_tnl_dev_init(struct net_device *dev)
if (err)
return err;
ip6_tnl_link_config(t);
if (t->parms.collect_md) {
dev->features |= NETIF_F_NETNS_LOCAL;
netif_keep_dst(dev);
}
return 0;
}

Expand Down Expand Up @@ -1811,6 +1886,9 @@ static void ip6_tnl_netlink_parms(struct nlattr *data[],

if (data[IFLA_IPTUN_PROTO])
parms->proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);

if (data[IFLA_IPTUN_COLLECT_METADATA])
parms->collect_md = true;
}

static bool ip6_tnl_netlink_encap_parms(struct nlattr *data[],
Expand Down Expand Up @@ -1850,6 +1928,7 @@ static int ip6_tnl_newlink(struct net *src_net, struct net_device *dev,
struct nlattr *tb[], struct nlattr *data[])
{
struct net *net = dev_net(dev);
struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
struct ip6_tnl *nt, *t;
struct ip_tunnel_encap ipencap;

Expand All @@ -1864,9 +1943,14 @@ static int ip6_tnl_newlink(struct net *src_net, struct net_device *dev,

ip6_tnl_netlink_parms(data, &nt->parms);

t = ip6_tnl_locate(net, &nt->parms, 0);
if (!IS_ERR(t))
return -EEXIST;
if (nt->parms.collect_md) {
if (rtnl_dereference(ip6n->collect_md_tun))
return -EEXIST;
} else {
t = ip6_tnl_locate(net, &nt->parms, 0);
if (!IS_ERR(t))
return -EEXIST;
}

return ip6_tnl_create2(dev);
}
Expand All @@ -1890,6 +1974,8 @@ static int ip6_tnl_changelink(struct net_device *dev, struct nlattr *tb[],
return err;
}
ip6_tnl_netlink_parms(data, &p);
if (p.collect_md)
return -EINVAL;

t = ip6_tnl_locate(net, &p, 0);
if (!IS_ERR(t)) {
Expand Down Expand Up @@ -1937,6 +2023,8 @@ static size_t ip6_tnl_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 All @@ -1955,16 +2043,15 @@ static int ip6_tnl_fill_info(struct sk_buff *skb, const struct net_device *dev)
nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->proto))
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))
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;

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

nla_put_failure:
Expand Down Expand Up @@ -1992,6 +2079,7 @@ static const struct nla_policy ip6_tnl_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 ip6_link_ops __read_mostly = {
Expand Down

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