linux/net/ipv6/seg6.c
David Lebrun d1df6fd8a1 ipv6: sr: define core operations for seg6local lightweight tunnel
This patch implements a new type of lightweight tunnel named seg6local.
A seg6local lwt is defined by a type of action and a set of parameters.
The action represents the operation to perform on the packets matching the
lwt's route, and is not necessarily an encapsulation. The set of parameters
are arguments for the processing function.

Each action is defined in a struct seg6_action_desc within
seg6_action_table[]. This structure contains the action, mandatory
attributes, the processing function, and a static headroom size required by
the action. The mandatory attributes are encoded as a bitmask field. The
static headroom is set to a non-zero value when the processing function
always add a constant number of bytes to the skb (e.g. the header size for
encapsulations).

To facilitate rtnetlink-related operations such as parsing, fill_encap,
and cmp_encap, each type of action parameter is associated to three
function pointers, in seg6_action_params[].

All actions defined in seg6_local.h are detailed in [1].

[1] https://tools.ietf.org/html/draft-filsfils-spring-srv6-network-programming-01

Signed-off-by: David Lebrun <david.lebrun@uclouvain.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-07 14:16:22 -07:00

502 lines
9.9 KiB
C

/*
* SR-IPv6 implementation
*
* Author:
* David Lebrun <david.lebrun@uclouvain.be>
*
*
* 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.
*/
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/net.h>
#include <linux/in6.h>
#include <linux/slab.h>
#include <net/ipv6.h>
#include <net/protocol.h>
#include <net/seg6.h>
#include <net/genetlink.h>
#include <linux/seg6.h>
#include <linux/seg6_genl.h>
#ifdef CONFIG_IPV6_SEG6_HMAC
#include <net/seg6_hmac.h>
#endif
bool seg6_validate_srh(struct ipv6_sr_hdr *srh, int len)
{
int trailing;
unsigned int tlv_offset;
if (srh->type != IPV6_SRCRT_TYPE_4)
return false;
if (((srh->hdrlen + 1) << 3) != len)
return false;
if (srh->segments_left > srh->first_segment)
return false;
tlv_offset = sizeof(*srh) + ((srh->first_segment + 1) << 4);
trailing = len - tlv_offset;
if (trailing < 0)
return false;
while (trailing) {
struct sr6_tlv *tlv;
unsigned int tlv_len;
if (trailing < sizeof(*tlv))
return false;
tlv = (struct sr6_tlv *)((unsigned char *)srh + tlv_offset);
tlv_len = sizeof(*tlv) + tlv->len;
trailing -= tlv_len;
if (trailing < 0)
return false;
tlv_offset += tlv_len;
}
return true;
}
static struct genl_family seg6_genl_family;
static const struct nla_policy seg6_genl_policy[SEG6_ATTR_MAX + 1] = {
[SEG6_ATTR_DST] = { .type = NLA_BINARY,
.len = sizeof(struct in6_addr) },
[SEG6_ATTR_DSTLEN] = { .type = NLA_S32, },
[SEG6_ATTR_HMACKEYID] = { .type = NLA_U32, },
[SEG6_ATTR_SECRET] = { .type = NLA_BINARY, },
[SEG6_ATTR_SECRETLEN] = { .type = NLA_U8, },
[SEG6_ATTR_ALGID] = { .type = NLA_U8, },
[SEG6_ATTR_HMACINFO] = { .type = NLA_NESTED, },
};
#ifdef CONFIG_IPV6_SEG6_HMAC
static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
{
struct net *net = genl_info_net(info);
struct seg6_pernet_data *sdata;
struct seg6_hmac_info *hinfo;
u32 hmackeyid;
char *secret;
int err = 0;
u8 algid;
u8 slen;
sdata = seg6_pernet(net);
if (!info->attrs[SEG6_ATTR_HMACKEYID] ||
!info->attrs[SEG6_ATTR_SECRETLEN] ||
!info->attrs[SEG6_ATTR_ALGID])
return -EINVAL;
hmackeyid = nla_get_u32(info->attrs[SEG6_ATTR_HMACKEYID]);
slen = nla_get_u8(info->attrs[SEG6_ATTR_SECRETLEN]);
algid = nla_get_u8(info->attrs[SEG6_ATTR_ALGID]);
if (hmackeyid == 0)
return -EINVAL;
if (slen > SEG6_HMAC_SECRET_LEN)
return -EINVAL;
mutex_lock(&sdata->lock);
hinfo = seg6_hmac_info_lookup(net, hmackeyid);
if (!slen) {
if (!hinfo)
err = -ENOENT;
err = seg6_hmac_info_del(net, hmackeyid);
goto out_unlock;
}
if (!info->attrs[SEG6_ATTR_SECRET]) {
err = -EINVAL;
goto out_unlock;
}
if (hinfo) {
err = seg6_hmac_info_del(net, hmackeyid);
if (err)
goto out_unlock;
}
secret = (char *)nla_data(info->attrs[SEG6_ATTR_SECRET]);
hinfo = kzalloc(sizeof(*hinfo), GFP_KERNEL);
if (!hinfo) {
err = -ENOMEM;
goto out_unlock;
}
memcpy(hinfo->secret, secret, slen);
hinfo->slen = slen;
hinfo->alg_id = algid;
hinfo->hmackeyid = hmackeyid;
err = seg6_hmac_info_add(net, hmackeyid, hinfo);
if (err)
kfree(hinfo);
out_unlock:
mutex_unlock(&sdata->lock);
return err;
}
#else
static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
{
return -ENOTSUPP;
}
#endif
static int seg6_genl_set_tunsrc(struct sk_buff *skb, struct genl_info *info)
{
struct net *net = genl_info_net(info);
struct in6_addr *val, *t_old, *t_new;
struct seg6_pernet_data *sdata;
sdata = seg6_pernet(net);
if (!info->attrs[SEG6_ATTR_DST])
return -EINVAL;
val = nla_data(info->attrs[SEG6_ATTR_DST]);
t_new = kmemdup(val, sizeof(*val), GFP_KERNEL);
if (!t_new)
return -ENOMEM;
mutex_lock(&sdata->lock);
t_old = sdata->tun_src;
rcu_assign_pointer(sdata->tun_src, t_new);
mutex_unlock(&sdata->lock);
synchronize_net();
kfree(t_old);
return 0;
}
static int seg6_genl_get_tunsrc(struct sk_buff *skb, struct genl_info *info)
{
struct net *net = genl_info_net(info);
struct in6_addr *tun_src;
struct sk_buff *msg;
void *hdr;
msg = genlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
if (!msg)
return -ENOMEM;
hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
&seg6_genl_family, 0, SEG6_CMD_GET_TUNSRC);
if (!hdr)
goto free_msg;
rcu_read_lock();
tun_src = rcu_dereference(seg6_pernet(net)->tun_src);
if (nla_put(msg, SEG6_ATTR_DST, sizeof(struct in6_addr), tun_src))
goto nla_put_failure;
rcu_read_unlock();
genlmsg_end(msg, hdr);
genlmsg_reply(msg, info);
return 0;
nla_put_failure:
rcu_read_unlock();
genlmsg_cancel(msg, hdr);
free_msg:
nlmsg_free(msg);
return -ENOMEM;
}
#ifdef CONFIG_IPV6_SEG6_HMAC
static int __seg6_hmac_fill_info(struct seg6_hmac_info *hinfo,
struct sk_buff *msg)
{
if (nla_put_u32(msg, SEG6_ATTR_HMACKEYID, hinfo->hmackeyid) ||
nla_put_u8(msg, SEG6_ATTR_SECRETLEN, hinfo->slen) ||
nla_put(msg, SEG6_ATTR_SECRET, hinfo->slen, hinfo->secret) ||
nla_put_u8(msg, SEG6_ATTR_ALGID, hinfo->alg_id))
return -1;
return 0;
}
static int __seg6_genl_dumphmac_element(struct seg6_hmac_info *hinfo,
u32 portid, u32 seq, u32 flags,
struct sk_buff *skb, u8 cmd)
{
void *hdr;
hdr = genlmsg_put(skb, portid, seq, &seg6_genl_family, flags, cmd);
if (!hdr)
return -ENOMEM;
if (__seg6_hmac_fill_info(hinfo, skb) < 0)
goto nla_put_failure;
genlmsg_end(skb, hdr);
return 0;
nla_put_failure:
genlmsg_cancel(skb, hdr);
return -EMSGSIZE;
}
static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
{
struct net *net = sock_net(cb->skb->sk);
struct seg6_pernet_data *sdata;
struct rhashtable_iter *iter;
sdata = seg6_pernet(net);
iter = (struct rhashtable_iter *)cb->args[0];
if (!iter) {
iter = kmalloc(sizeof(*iter), GFP_KERNEL);
if (!iter)
return -ENOMEM;
cb->args[0] = (long)iter;
}
rhashtable_walk_enter(&sdata->hmac_infos, iter);
return 0;
}
static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
{
struct rhashtable_iter *iter = (struct rhashtable_iter *)cb->args[0];
rhashtable_walk_exit(iter);
kfree(iter);
return 0;
}
static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
{
struct rhashtable_iter *iter = (struct rhashtable_iter *)cb->args[0];
struct seg6_hmac_info *hinfo;
int ret;
ret = rhashtable_walk_start(iter);
if (ret && ret != -EAGAIN)
goto done;
for (;;) {
hinfo = rhashtable_walk_next(iter);
if (IS_ERR(hinfo)) {
if (PTR_ERR(hinfo) == -EAGAIN)
continue;
ret = PTR_ERR(hinfo);
goto done;
} else if (!hinfo) {
break;
}
ret = __seg6_genl_dumphmac_element(hinfo,
NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq,
NLM_F_MULTI,
skb, SEG6_CMD_DUMPHMAC);
if (ret)
goto done;
}
ret = skb->len;
done:
rhashtable_walk_stop(iter);
return ret;
}
#else
static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
{
return 0;
}
static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
{
return 0;
}
static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
{
return -ENOTSUPP;
}
#endif
static int __net_init seg6_net_init(struct net *net)
{
struct seg6_pernet_data *sdata;
sdata = kzalloc(sizeof(*sdata), GFP_KERNEL);
if (!sdata)
return -ENOMEM;
mutex_init(&sdata->lock);
sdata->tun_src = kzalloc(sizeof(*sdata->tun_src), GFP_KERNEL);
if (!sdata->tun_src) {
kfree(sdata);
return -ENOMEM;
}
net->ipv6.seg6_data = sdata;
#ifdef CONFIG_IPV6_SEG6_HMAC
seg6_hmac_net_init(net);
#endif
return 0;
}
static void __net_exit seg6_net_exit(struct net *net)
{
struct seg6_pernet_data *sdata = seg6_pernet(net);
#ifdef CONFIG_IPV6_SEG6_HMAC
seg6_hmac_net_exit(net);
#endif
kfree(sdata->tun_src);
kfree(sdata);
}
static struct pernet_operations ip6_segments_ops = {
.init = seg6_net_init,
.exit = seg6_net_exit,
};
static const struct genl_ops seg6_genl_ops[] = {
{
.cmd = SEG6_CMD_SETHMAC,
.doit = seg6_genl_sethmac,
.policy = seg6_genl_policy,
.flags = GENL_ADMIN_PERM,
},
{
.cmd = SEG6_CMD_DUMPHMAC,
.start = seg6_genl_dumphmac_start,
.dumpit = seg6_genl_dumphmac,
.done = seg6_genl_dumphmac_done,
.policy = seg6_genl_policy,
.flags = GENL_ADMIN_PERM,
},
{
.cmd = SEG6_CMD_SET_TUNSRC,
.doit = seg6_genl_set_tunsrc,
.policy = seg6_genl_policy,
.flags = GENL_ADMIN_PERM,
},
{
.cmd = SEG6_CMD_GET_TUNSRC,
.doit = seg6_genl_get_tunsrc,
.policy = seg6_genl_policy,
.flags = GENL_ADMIN_PERM,
},
};
static struct genl_family seg6_genl_family __ro_after_init = {
.hdrsize = 0,
.name = SEG6_GENL_NAME,
.version = SEG6_GENL_VERSION,
.maxattr = SEG6_ATTR_MAX,
.netnsok = true,
.parallel_ops = true,
.ops = seg6_genl_ops,
.n_ops = ARRAY_SIZE(seg6_genl_ops),
.module = THIS_MODULE,
};
int __init seg6_init(void)
{
int err = -ENOMEM;
err = genl_register_family(&seg6_genl_family);
if (err)
goto out;
err = register_pernet_subsys(&ip6_segments_ops);
if (err)
goto out_unregister_genl;
#ifdef CONFIG_IPV6_SEG6_LWTUNNEL
err = seg6_iptunnel_init();
if (err)
goto out_unregister_pernet;
err = seg6_local_init();
if (err)
goto out_unregister_pernet;
#endif
#ifdef CONFIG_IPV6_SEG6_HMAC
err = seg6_hmac_init();
if (err)
goto out_unregister_iptun;
#endif
pr_info("Segment Routing with IPv6\n");
out:
return err;
#ifdef CONFIG_IPV6_SEG6_HMAC
out_unregister_iptun:
#ifdef CONFIG_IPV6_SEG6_LWTUNNEL
seg6_local_exit();
seg6_iptunnel_exit();
#endif
#endif
#ifdef CONFIG_IPV6_SEG6_LWTUNNEL
out_unregister_pernet:
unregister_pernet_subsys(&ip6_segments_ops);
#endif
out_unregister_genl:
genl_unregister_family(&seg6_genl_family);
goto out;
}
void seg6_exit(void)
{
#ifdef CONFIG_IPV6_SEG6_HMAC
seg6_hmac_exit();
#endif
#ifdef CONFIG_IPV6_SEG6_LWTUNNEL
seg6_iptunnel_exit();
#endif
unregister_pernet_subsys(&ip6_segments_ops);
genl_unregister_family(&seg6_genl_family);
}