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// SPDX-License-Identifier: GPL-2.0+
/*
* IPv6 IOAM Lightweight Tunnel implementation
*
* Author:
* Justin Iurman <justin.iurman@uliege.be>
*/
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/net.h>
#include <linux/in6.h>
#include <linux/ioam6.h>
#include <linux/ioam6_iptunnel.h>
#include <net/dst.h>
#include <net/sock.h>
#include <net/lwtunnel.h>
#include <net/ioam6.h>
#include <net/netlink.h>
#define IOAM6_MASK_SHORT_FIELDS 0xff100000
#define IOAM6_MASK_WIDE_FIELDS 0xe00000
struct ioam6_lwt_encap {
struct ipv6_hopopt_hdr eh;
u8 pad[2]; /* 2-octet padding for 4n-alignment */
struct ioam6_hdr ioamh;
struct ioam6_trace_hdr traceh;
} __packed;
struct ioam6_lwt {
struct ioam6_lwt_encap tuninfo;
};
static struct ioam6_lwt *ioam6_lwt_state(struct lwtunnel_state *lwt)
{
return (struct ioam6_lwt *)lwt->data;
}
static struct ioam6_lwt_encap *ioam6_lwt_info(struct lwtunnel_state *lwt)
{
return &ioam6_lwt_state(lwt)->tuninfo;
}
static struct ioam6_trace_hdr *ioam6_lwt_trace(struct lwtunnel_state *lwt)
{
return &(ioam6_lwt_state(lwt)->tuninfo.traceh);
}
static const struct nla_policy ioam6_iptunnel_policy[IOAM6_IPTUNNEL_MAX + 1] = {
[IOAM6_IPTUNNEL_TRACE] = NLA_POLICY_EXACT_LEN(sizeof(struct ioam6_trace_hdr)),
};
static bool ioam6_validate_trace_hdr(struct ioam6_trace_hdr *trace)
{
u32 fields;
if (!trace->type_be32 || !trace->remlen ||
trace->remlen > IOAM6_TRACE_DATA_SIZE_MAX / 4)
return false;
trace->nodelen = 0;
fields = be32_to_cpu(trace->type_be32);
trace->nodelen += hweight32(fields & IOAM6_MASK_SHORT_FIELDS)
* (sizeof(__be32) / 4);
trace->nodelen += hweight32(fields & IOAM6_MASK_WIDE_FIELDS)
* (sizeof(__be64) / 4);
return true;
}
static int ioam6_build_state(struct net *net, struct nlattr *nla,
unsigned int family, const void *cfg,
struct lwtunnel_state **ts,
struct netlink_ext_ack *extack)
{
struct nlattr *tb[IOAM6_IPTUNNEL_MAX + 1];
struct ioam6_lwt_encap *tuninfo;
struct ioam6_trace_hdr *trace;
struct lwtunnel_state *s;
int len_aligned;
int len, err;
if (family != AF_INET6)
return -EINVAL;
err = nla_parse_nested(tb, IOAM6_IPTUNNEL_MAX, nla,
ioam6_iptunnel_policy, extack);
if (err < 0)
return err;
if (!tb[IOAM6_IPTUNNEL_TRACE]) {
NL_SET_ERR_MSG(extack, "missing trace");
return -EINVAL;
}
trace = nla_data(tb[IOAM6_IPTUNNEL_TRACE]);
if (!ioam6_validate_trace_hdr(trace)) {
NL_SET_ERR_MSG_ATTR(extack, tb[IOAM6_IPTUNNEL_TRACE],
"invalid trace validation");
return -EINVAL;
}
len = sizeof(*tuninfo) + trace->remlen * 4;
len_aligned = ALIGN(len, 8);
s = lwtunnel_state_alloc(len_aligned);
if (!s)
return -ENOMEM;
tuninfo = ioam6_lwt_info(s);
tuninfo->eh.hdrlen = (len_aligned >> 3) - 1;
tuninfo->pad[0] = IPV6_TLV_PADN;
tuninfo->ioamh.type = IOAM6_TYPE_PREALLOC;
tuninfo->ioamh.opt_type = IPV6_TLV_IOAM;
tuninfo->ioamh.opt_len = sizeof(tuninfo->ioamh) - 2 + sizeof(*trace)
+ trace->remlen * 4;
memcpy(&tuninfo->traceh, trace, sizeof(*trace));
len = len_aligned - len;
if (len == 1) {
tuninfo->traceh.data[trace->remlen * 4] = IPV6_TLV_PAD1;
} else if (len > 0) {
tuninfo->traceh.data[trace->remlen * 4] = IPV6_TLV_PADN;
tuninfo->traceh.data[trace->remlen * 4 + 1] = len - 2;
}
s->type = LWTUNNEL_ENCAP_IOAM6;
s->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT;
*ts = s;
return 0;
}
static int ioam6_do_inline(struct sk_buff *skb, struct ioam6_lwt_encap *tuninfo)
{
struct ioam6_trace_hdr *trace;
struct ipv6hdr *oldhdr, *hdr;
struct ioam6_namespace *ns;
int hdrlen, err;
hdrlen = (tuninfo->eh.hdrlen + 1) << 3;
err = skb_cow_head(skb, hdrlen + skb->mac_len);
if (unlikely(err))
return err;
oldhdr = ipv6_hdr(skb);
skb_pull(skb, sizeof(*oldhdr));
skb_postpull_rcsum(skb, skb_network_header(skb), sizeof(*oldhdr));
skb_push(skb, sizeof(*oldhdr) + hdrlen);
skb_reset_network_header(skb);
skb_mac_header_rebuild(skb);
hdr = ipv6_hdr(skb);
memmove(hdr, oldhdr, sizeof(*oldhdr));
tuninfo->eh.nexthdr = hdr->nexthdr;
skb_set_transport_header(skb, sizeof(*hdr));
skb_postpush_rcsum(skb, hdr, sizeof(*hdr) + hdrlen);
memcpy(skb_transport_header(skb), (u8 *)tuninfo, hdrlen);
hdr->nexthdr = NEXTHDR_HOP;
hdr->payload_len = cpu_to_be16(skb->len - sizeof(*hdr));
trace = (struct ioam6_trace_hdr *)(skb_transport_header(skb)
+ sizeof(struct ipv6_hopopt_hdr) + 2
+ sizeof(struct ioam6_hdr));
ns = ioam6_namespace(dev_net(skb_dst(skb)->dev), trace->namespace_id);
if (ns)
ioam6_fill_trace_data(skb, ns, trace);
return 0;
}
static int ioam6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
struct lwtunnel_state *lwt = skb_dst(skb)->lwtstate;
int err = -EINVAL;
if (skb->protocol != htons(ETH_P_IPV6))
goto drop;
/* Only for packets we send and
* that do not contain a Hop-by-Hop yet
*/
if (skb->dev || ipv6_hdr(skb)->nexthdr == NEXTHDR_HOP)
goto out;
err = ioam6_do_inline(skb, ioam6_lwt_info(lwt));
if (unlikely(err))
goto drop;
err = skb_cow_head(skb, LL_RESERVED_SPACE(skb_dst(skb)->dev));
if (unlikely(err))
goto drop;
out:
return lwt->orig_output(net, sk, skb);
drop:
kfree_skb(skb);
return err;
}
static int ioam6_fill_encap_info(struct sk_buff *skb,
struct lwtunnel_state *lwtstate)
{
struct ioam6_trace_hdr *trace;
int err;
trace = ioam6_lwt_trace(lwtstate);
err = nla_put(skb, IOAM6_IPTUNNEL_TRACE, sizeof(*trace), trace);
if (err)
return err;
return 0;
}
static int ioam6_encap_nlsize(struct lwtunnel_state *lwtstate)
{
struct ioam6_trace_hdr *trace = ioam6_lwt_trace(lwtstate);
return nla_total_size(sizeof(*trace));
}
static int ioam6_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
{
struct ioam6_trace_hdr *a_hdr = ioam6_lwt_trace(a);
struct ioam6_trace_hdr *b_hdr = ioam6_lwt_trace(b);
return (a_hdr->namespace_id != b_hdr->namespace_id);
}
static const struct lwtunnel_encap_ops ioam6_iptun_ops = {
.build_state = ioam6_build_state,
.output = ioam6_output,
.fill_encap = ioam6_fill_encap_info,
.get_encap_size = ioam6_encap_nlsize,
.cmp_encap = ioam6_encap_cmp,
.owner = THIS_MODULE,
};
int __init ioam6_iptunnel_init(void)
{
return lwtunnel_encap_add_ops(&ioam6_iptun_ops, LWTUNNEL_ENCAP_IOAM6);
}
void ioam6_iptunnel_exit(void)
{
lwtunnel_encap_del_ops(&ioam6_iptun_ops, LWTUNNEL_ENCAP_IOAM6);
}
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