--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/**
+ * Authors:
+ * (C) 2020 Alexander Aring <alex.aring@gmail.com>
+ */
+
+#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 {
+ struct ipv6_rpl_sr_hdr srh[0];
+};
+
+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 = kzalloc(ipv6_rpl_srh_alloc_size(srh->segments_left - 1) * 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))
+ 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;
+ int err = 0;
+
+ if (skb->protocol != htons(ETH_P_IPV6))
+ return -EINVAL;
+
+ tinfo = rpl_encap_lwtunnel(dst->lwtstate);
+
+ err = rpl_do_srh_inline(skb, rlwt, tinfo->srh);
+ if (err)
+ return err;
+
+ return 0;
+}
+
+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 = -EINVAL;
+
+ rlwt = rpl_lwt_lwtunnel(orig_dst->lwtstate);
+
+ err = rpl_do_srh(skb, rlwt);
+ if (unlikely(err))
+ goto drop;
+
+ preempt_disable();
+ dst = dst_cache_get(&rlwt->cache);
+ preempt_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;
+ }
+
+ preempt_disable();
+ dst_cache_set_ip6(&rlwt->cache, dst, &fl6.saddr);
+ preempt_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)) {
+ kfree_skb(skb);
+ return err;
+ }
+
+ preempt_disable();
+ dst = dst_cache_get(&rlwt->cache);
+ preempt_enable();
+
+ skb_dst_drop(skb);
+
+ if (!dst) {
+ ip6_route_input(skb);
+ dst = skb_dst(skb);
+ if (!dst->error) {
+ preempt_disable();
+ dst_cache_set_ip6(&rlwt->cache, dst,
+ &ipv6_hdr(skb)->saddr);
+ preempt_enable();
+ }
+ } else {
+ skb_dst_set(skb, dst);
+ }
+
+ err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
+ if (unlikely(err))
+ return err;
+
+ return dst_input(skb);
+}
+
+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);
+}
projects / openwrt / staging / blogic.git / commitdiff