// SPDX-License-Identifier: GPL-2.0-only
/*
* Authors:
* (C) 2020 Alexander Aring <[email protected]>
*/
#include <linux/rpl_iptunnel.h>
#include <net/dst_cache.h>
#include <net/ip6_route.h>
#include <net/lwtunnel.h>
#include <net/ipv6.h>
#include <net/rpl.h>
struct rpl_iptunnel_encap {
DECLARE_FLEX_ARRAY(struct ipv6_rpl_sr_hdr, srh);
};
struct rpl_lwt {
struct dst_cache cache;
struct rpl_iptunnel_encap tuninfo;
};
static inline struct rpl_lwt *rpl_lwt_lwtunnel(struct lwtunnel_state *lwt)
{
return (struct rpl_lwt *)lwt->data;
}
static inline struct rpl_iptunnel_encap *
rpl_encap_lwtunnel(struct lwtunnel_state *lwt)
{
return &rpl_lwt_lwtunnel(lwt)->tuninfo;
}
static const struct nla_policy rpl_iptunnel_policy[RPL_IPTUNNEL_MAX + 1] = {
[RPL_IPTUNNEL_SRH] = { .type = NLA_BINARY },
};
static bool rpl_validate_srh(struct net *net, struct ipv6_rpl_sr_hdr *srh,
size_t seglen)
{
int err;
if ((srh->hdrlen << 3) != seglen)
return false;
/* check at least one segment and seglen fit with segments_left */
if (!srh->segments_left ||
(srh->segments_left * sizeof(struct in6_addr)) != seglen)
return false;
if (srh->cmpri || srh->cmpre)
return false;
err = ipv6_chk_rpl_srh_loop(net, srh->rpl_segaddr,
srh->segments_left);
if (err)
return false;
if (ipv6_addr_type(&srh->rpl_segaddr[srh->segments_left - 1]) &
IPV6_ADDR_MULTICAST)
return false;
return true;
}
static int rpl_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[RPL_IPTUNNEL_MAX + 1];
struct lwtunnel_state *newts;
struct ipv6_rpl_sr_hdr *srh;
struct rpl_lwt *rlwt;
int err, srh_len;
if (family != AF_INET6)
return -EINVAL;
err = nla_parse_nested(tb, RPL_IPTUNNEL_MAX, nla,
rpl_iptunnel_policy, extack);
if (err < 0)
return err;
if (!tb[RPL_IPTUNNEL_SRH])
return -EINVAL;
srh = nla_data(tb[RPL_IPTUNNEL_SRH]);
srh_len = nla_len(tb[RPL_IPTUNNEL_SRH]);
if (srh_len < sizeof(*srh))
return -EINVAL;
/* verify that SRH is consistent */
if (!rpl_validate_srh(net, srh, srh_len - sizeof(*srh)))
return -EINVAL;
newts = lwtunnel_state_alloc(srh_len + sizeof(*rlwt));
if (!newts)
return -ENOMEM;
rlwt = rpl_lwt_lwtunnel(newts);
err = dst_cache_init(&rlwt->cache, GFP_ATOMIC);
if (err) {
kfree(newts);
return err;
}
memcpy(&rlwt->tuninfo.srh, srh, srh_len);
newts->type = LWTUNNEL_ENCAP_RPL;
newts->flags |= LWTUNNEL_STATE_INPUT_REDIRECT;
newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT;
*ts = newts;
return 0;
}
static void rpl_destroy_state(struct lwtunnel_state *lwt)
{
dst_cache_destroy(&rpl_lwt_lwtunnel(lwt)->cache);
}
static int rpl_do_srh_inline(struct sk_buff *skb, const struct rpl_lwt *rlwt,
const struct ipv6_rpl_sr_hdr *srh)
{
struct ipv6_rpl_sr_hdr *isrh, *csrh;
const struct ipv6hdr *oldhdr;
struct ipv6hdr *hdr;
unsigned char *buf;
size_t hdrlen;
int err;
oldhdr = ipv6_hdr(skb);
buf = kcalloc(struct_size(srh, segments.addr, srh->segments_left), 2, GFP_ATOMIC);
if (!buf)
return -ENOMEM;
isrh = (struct ipv6_rpl_sr_hdr *)buf;
csrh = (struct ipv6_rpl_sr_hdr *)(buf + ((srh->hdrlen + 1) << 3));
memcpy(isrh, srh, sizeof(*isrh));
memcpy(isrh->rpl_segaddr, &srh->rpl_segaddr[1],
(srh->segments_left - 1) * 16);
isrh->rpl_segaddr[srh->segments_left - 1] = oldhdr->daddr;
ipv6_rpl_srh_compress(csrh, isrh, &srh->rpl_segaddr[0],
isrh->segments_left - 1);
hdrlen = ((csrh->hdrlen + 1) << 3);
err = skb_cow_head(skb, hdrlen + skb->mac_len);
if (unlikely(err)) {
kfree(buf);
return err;
}
skb_pull(skb, sizeof(struct ipv6hdr));
skb_postpull_rcsum(skb, skb_network_header(skb),
sizeof(struct ipv6hdr));
skb_push(skb, sizeof(struct ipv6hdr) + hdrlen);
skb_reset_network_header(skb);
skb_mac_header_rebuild(skb);
hdr = ipv6_hdr(skb);
memmove(hdr, oldhdr, sizeof(*hdr));
isrh = (void *)hdr + sizeof(*hdr);
memcpy(isrh, csrh, hdrlen);
isrh->nexthdr = hdr->nexthdr;
hdr->nexthdr = NEXTHDR_ROUTING;
hdr->daddr = srh->rpl_segaddr[0];
ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
skb_set_transport_header(skb, sizeof(struct ipv6hdr));
skb_postpush_rcsum(skb, hdr, sizeof(struct ipv6hdr) + hdrlen);
kfree(buf);
return 0;
}
static int rpl_do_srh(struct sk_buff *skb, const struct rpl_lwt *rlwt)
{
struct dst_entry *dst = skb_dst(skb);
struct rpl_iptunnel_encap *tinfo;
if (skb->protocol != htons(ETH_P_IPV6))
return -EINVAL;
tinfo = rpl_encap_lwtunnel(dst->lwtstate);
return rpl_do_srh_inline(skb, rlwt, tinfo->srh);
}
static int rpl_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
struct dst_entry *orig_dst = skb_dst(skb);
struct dst_entry *dst = NULL;
struct rpl_lwt *rlwt;
int err;
rlwt = rpl_lwt_lwtunnel(orig_dst->lwtstate);
err = rpl_do_srh(skb, rlwt);
if (unlikely(err))
goto drop;
local_bh_disable();
dst = dst_cache_get(&rlwt->cache);
local_bh_enable();
if (unlikely(!dst)) {
struct ipv6hdr *hdr = ipv6_hdr(skb);
struct flowi6 fl6;
memset(&fl6, 0, sizeof(fl6));
fl6.daddr = hdr->daddr;
fl6.saddr = hdr->saddr;
fl6.flowlabel = ip6_flowinfo(hdr);
fl6.flowi6_mark = skb->mark;
fl6.flowi6_proto = hdr->nexthdr;
dst = ip6_route_output(net, NULL, &fl6);
if (dst->error) {
err = dst->error;
dst_release(dst);
goto drop;
}
local_bh_disable();
dst_cache_set_ip6(&rlwt->cache, dst, &fl6.saddr);
local_bh_enable();
}
skb_dst_drop(skb);
skb_dst_set(skb, dst);
err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
if (unlikely(err))
goto drop;
return dst_output(net, sk, skb);
drop:
kfree_skb(skb);
return err;
}
static int rpl_input(struct sk_buff *skb)
{
struct dst_entry *orig_dst = skb_dst(skb);
struct dst_entry *dst = NULL;
struct rpl_lwt *rlwt;
int err;
rlwt = rpl_lwt_lwtunnel(orig_dst->lwtstate);
err = rpl_do_srh(skb, rlwt);
if (unlikely(err))
goto drop;
local_bh_disable();
dst = dst_cache_get(&rlwt->cache);
if (!dst) {
ip6_route_input(skb);
dst = skb_dst(skb);
if (!dst->error) {
dst_cache_set_ip6(&rlwt->cache, dst,
&ipv6_hdr(skb)->saddr);
}
} else {
skb_dst_drop(skb);
skb_dst_set(skb, dst);
}
local_bh_enable();
err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
if (unlikely(err))
goto drop;
return dst_input(skb);
drop:
kfree_skb(skb);
return err;
}
static int nla_put_rpl_srh(struct sk_buff *skb, int attrtype,
struct rpl_iptunnel_encap *tuninfo)
{
struct rpl_iptunnel_encap *data;
struct nlattr *nla;
int len;
len = RPL_IPTUNNEL_SRH_SIZE(tuninfo->srh);
nla = nla_reserve(skb, attrtype, len);
if (!nla)
return -EMSGSIZE;
data = nla_data(nla);
memcpy(data, tuninfo->srh, len);
return 0;
}
static int rpl_fill_encap_info(struct sk_buff *skb,
struct lwtunnel_state *lwtstate)
{
struct rpl_iptunnel_encap *tuninfo = rpl_encap_lwtunnel(lwtstate);
if (nla_put_rpl_srh(skb, RPL_IPTUNNEL_SRH, tuninfo))
return -EMSGSIZE;
return 0;
}
static int rpl_encap_nlsize(struct lwtunnel_state *lwtstate)
{
struct rpl_iptunnel_encap *tuninfo = rpl_encap_lwtunnel(lwtstate);
return nla_total_size(RPL_IPTUNNEL_SRH_SIZE(tuninfo->srh));
}
static int rpl_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
{
struct rpl_iptunnel_encap *a_hdr = rpl_encap_lwtunnel(a);
struct rpl_iptunnel_encap *b_hdr = rpl_encap_lwtunnel(b);
int len = RPL_IPTUNNEL_SRH_SIZE(a_hdr->srh);
if (len != RPL_IPTUNNEL_SRH_SIZE(b_hdr->srh))
return 1;
return memcmp(a_hdr, b_hdr, len);
}
static const struct lwtunnel_encap_ops rpl_ops = {
.build_state = rpl_build_state,
.destroy_state = rpl_destroy_state,
.output = rpl_output,
.input = rpl_input,
.fill_encap = rpl_fill_encap_info,
.get_encap_size = rpl_encap_nlsize,
.cmp_encap = rpl_encap_cmp,
.owner = THIS_MODULE,
};
int __init rpl_init(void)
{
int err;
err = lwtunnel_encap_add_ops(&rpl_ops, LWTUNNEL_ENCAP_RPL);
if (err)
goto out;
pr_info("RPL Segment Routing with IPv6\n");
return 0;
out:
return err;
}
void rpl_exit(void)
{
lwtunnel_encap_del_ops(&rpl_ops, LWTUNNEL_ENCAP_RPL);
}
Codebase Browser
linux