swh:1:snp:0424f14fb59df2ee63d8659da5115ce9de06a349
Tip revision: 4fe89d07dcc2804c8b562f6c7896a45643d34b2f authored by Linus Torvalds on 02 October 2022, 21:09:07 UTC
Linux 6.0
Linux 6.0
Tip revision: 4fe89d0
seg6.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* SR-IPv6 implementation
*
* Author:
* David Lebrun <david.lebrun@uclouvain.be>
*/
#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 <linux/rhashtable.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, bool reduced)
{
unsigned int tlv_offset;
int max_last_entry;
int trailing;
if (srh->type != IPV6_SRCRT_TYPE_4)
return false;
if (((srh->hdrlen + 1) << 3) != len)
return false;
if (!reduced && srh->segments_left > srh->first_segment) {
return false;
} else {
max_last_entry = (srh->hdrlen / 2) - 1;
if (srh->first_segment > max_last_entry)
return false;
if (srh->segments_left > srh->first_segment + 1)
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;
}
struct ipv6_sr_hdr *seg6_get_srh(struct sk_buff *skb, int flags)
{
struct ipv6_sr_hdr *srh;
int len, srhoff = 0;
if (ipv6_find_hdr(skb, &srhoff, IPPROTO_ROUTING, NULL, &flags) < 0)
return NULL;
if (!pskb_may_pull(skb, srhoff + sizeof(*srh)))
return NULL;
srh = (struct ipv6_sr_hdr *)(skb->data + srhoff);
len = (srh->hdrlen + 1) << 3;
if (!pskb_may_pull(skb, srhoff + len))
return NULL;
/* note that pskb_may_pull may change pointers in header;
* for this reason it is necessary to reload them when needed.
*/
srh = (struct ipv6_sr_hdr *)(skb->data + srhoff);
if (!seg6_validate_srh(srh, len, true))
return NULL;
return srh;
}
/* Determine if an ICMP invoking packet contains a segment routing
* header. If it does, extract the offset to the true destination
* address, which is in the first segment address.
*/
void seg6_icmp_srh(struct sk_buff *skb, struct inet6_skb_parm *opt)
{
__u16 network_header = skb->network_header;
struct ipv6_sr_hdr *srh;
/* Update network header to point to the invoking packet
* inside the ICMP packet, so we can use the seg6_get_srh()
* helper.
*/
skb_reset_network_header(skb);
srh = seg6_get_srh(skb, 0);
if (!srh)
goto out;
if (srh->type != IPV6_SRCRT_TYPE_4)
goto out;
opt->flags |= IP6SKB_SEG6;
opt->srhoff = (unsigned char *)srh - skb->data;
out:
/* Restore the network header back to the ICMP packet */
skb->network_header = network_header;
}
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) {
err = seg6_hmac_info_del(net, hmackeyid);
goto out_unlock;
}
if (!info->attrs[SEG6_ATTR_SECRET]) {
err = -EINVAL;
goto out_unlock;
}
if (slen > nla_len(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);
return genlmsg_reply(msg, info);
nla_put_failure:
rcu_read_unlock();
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;
rhashtable_walk_start(iter);
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
if (seg6_hmac_net_init(net)) {
kfree(rcu_dereference_raw(sdata->tun_src));
kfree(sdata);
return -ENOMEM;
}
#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(rcu_dereference_raw(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,
.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
.doit = seg6_genl_sethmac,
.flags = GENL_ADMIN_PERM,
},
{
.cmd = SEG6_CMD_DUMPHMAC,
.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
.start = seg6_genl_dumphmac_start,
.dumpit = seg6_genl_dumphmac,
.done = seg6_genl_dumphmac_done,
.flags = GENL_ADMIN_PERM,
},
{
.cmd = SEG6_CMD_SET_TUNSRC,
.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
.doit = seg6_genl_set_tunsrc,
.flags = GENL_ADMIN_PERM,
},
{
.cmd = SEG6_CMD_GET_TUNSRC,
.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
.doit = seg6_genl_get_tunsrc,
.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,
.policy = seg6_genl_policy,
.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;
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);
}