v4.19.13 snapshot.
diff --git a/net/ipv6/seg6_iptunnel.c b/net/ipv6/seg6_iptunnel.c
new file mode 100644
index 0000000..8181ee7
--- /dev/null
+++ b/net/ipv6/seg6_iptunnel.c
@@ -0,0 +1,516 @@
+/*
+ * 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/types.h>
+#include <linux/skbuff.h>
+#include <linux/net.h>
+#include <linux/module.h>
+#include <net/ip.h>
+#include <net/ip_tunnels.h>
+#include <net/lwtunnel.h>
+#include <net/netevent.h>
+#include <net/netns/generic.h>
+#include <net/ip6_fib.h>
+#include <net/route.h>
+#include <net/seg6.h>
+#include <linux/seg6.h>
+#include <linux/seg6_iptunnel.h>
+#include <net/addrconf.h>
+#include <net/ip6_route.h>
+#include <net/dst_cache.h>
+#ifdef CONFIG_IPV6_SEG6_HMAC
+#include <net/seg6_hmac.h>
+#endif
+
+struct seg6_lwt {
+ struct dst_cache cache;
+ struct seg6_iptunnel_encap tuninfo[0];
+};
+
+static inline struct seg6_lwt *seg6_lwt_lwtunnel(struct lwtunnel_state *lwt)
+{
+ return (struct seg6_lwt *)lwt->data;
+}
+
+static inline struct seg6_iptunnel_encap *
+seg6_encap_lwtunnel(struct lwtunnel_state *lwt)
+{
+ return seg6_lwt_lwtunnel(lwt)->tuninfo;
+}
+
+static const struct nla_policy seg6_iptunnel_policy[SEG6_IPTUNNEL_MAX + 1] = {
+ [SEG6_IPTUNNEL_SRH] = { .type = NLA_BINARY },
+};
+
+static int nla_put_srh(struct sk_buff *skb, int attrtype,
+ struct seg6_iptunnel_encap *tuninfo)
+{
+ struct seg6_iptunnel_encap *data;
+ struct nlattr *nla;
+ int len;
+
+ len = SEG6_IPTUN_ENCAP_SIZE(tuninfo);
+
+ nla = nla_reserve(skb, attrtype, len);
+ if (!nla)
+ return -EMSGSIZE;
+
+ data = nla_data(nla);
+ memcpy(data, tuninfo, len);
+
+ return 0;
+}
+
+static void set_tun_src(struct net *net, struct net_device *dev,
+ struct in6_addr *daddr, struct in6_addr *saddr)
+{
+ struct seg6_pernet_data *sdata = seg6_pernet(net);
+ struct in6_addr *tun_src;
+
+ rcu_read_lock();
+
+ tun_src = rcu_dereference(sdata->tun_src);
+
+ if (!ipv6_addr_any(tun_src)) {
+ memcpy(saddr, tun_src, sizeof(struct in6_addr));
+ } else {
+ ipv6_dev_get_saddr(net, dev, daddr, IPV6_PREFER_SRC_PUBLIC,
+ saddr);
+ }
+
+ rcu_read_unlock();
+}
+
+/* Compute flowlabel for outer IPv6 header */
+static __be32 seg6_make_flowlabel(struct net *net, struct sk_buff *skb,
+ struct ipv6hdr *inner_hdr)
+{
+ int do_flowlabel = net->ipv6.sysctl.seg6_flowlabel;
+ __be32 flowlabel = 0;
+ u32 hash;
+
+ if (do_flowlabel > 0) {
+ hash = skb_get_hash(skb);
+ hash = rol32(hash, 16);
+ flowlabel = (__force __be32)hash & IPV6_FLOWLABEL_MASK;
+ } else if (!do_flowlabel && skb->protocol == htons(ETH_P_IPV6)) {
+ flowlabel = ip6_flowlabel(inner_hdr);
+ }
+ return flowlabel;
+}
+
+/* encapsulate an IPv6 packet within an outer IPv6 header with a given SRH */
+int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int proto)
+{
+ struct dst_entry *dst = skb_dst(skb);
+ struct net *net = dev_net(dst->dev);
+ struct ipv6hdr *hdr, *inner_hdr;
+ struct ipv6_sr_hdr *isrh;
+ int hdrlen, tot_len, err;
+ __be32 flowlabel;
+
+ hdrlen = (osrh->hdrlen + 1) << 3;
+ tot_len = hdrlen + sizeof(*hdr);
+
+ err = skb_cow_head(skb, tot_len + skb->mac_len);
+ if (unlikely(err))
+ return err;
+
+ inner_hdr = ipv6_hdr(skb);
+ flowlabel = seg6_make_flowlabel(net, skb, inner_hdr);
+
+ skb_push(skb, tot_len);
+ skb_reset_network_header(skb);
+ skb_mac_header_rebuild(skb);
+ hdr = ipv6_hdr(skb);
+
+ /* inherit tc, flowlabel and hlim
+ * hlim will be decremented in ip6_forward() afterwards and
+ * decapsulation will overwrite inner hlim with outer hlim
+ */
+
+ if (skb->protocol == htons(ETH_P_IPV6)) {
+ ip6_flow_hdr(hdr, ip6_tclass(ip6_flowinfo(inner_hdr)),
+ flowlabel);
+ hdr->hop_limit = inner_hdr->hop_limit;
+ } else {
+ ip6_flow_hdr(hdr, 0, flowlabel);
+ hdr->hop_limit = ip6_dst_hoplimit(skb_dst(skb));
+ }
+
+ hdr->nexthdr = NEXTHDR_ROUTING;
+
+ isrh = (void *)hdr + sizeof(*hdr);
+ memcpy(isrh, osrh, hdrlen);
+
+ isrh->nexthdr = proto;
+
+ hdr->daddr = isrh->segments[isrh->first_segment];
+ set_tun_src(net, dst->dev, &hdr->daddr, &hdr->saddr);
+
+#ifdef CONFIG_IPV6_SEG6_HMAC
+ if (sr_has_hmac(isrh)) {
+ err = seg6_push_hmac(net, &hdr->saddr, isrh);
+ if (unlikely(err))
+ return err;
+ }
+#endif
+
+ skb_postpush_rcsum(skb, hdr, tot_len);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(seg6_do_srh_encap);
+
+/* insert an SRH within an IPv6 packet, just after the IPv6 header */
+int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh)
+{
+ struct ipv6hdr *hdr, *oldhdr;
+ struct ipv6_sr_hdr *isrh;
+ int hdrlen, err;
+
+ hdrlen = (osrh->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(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, osrh, hdrlen);
+
+ isrh->nexthdr = hdr->nexthdr;
+ hdr->nexthdr = NEXTHDR_ROUTING;
+
+ isrh->segments[0] = hdr->daddr;
+ hdr->daddr = isrh->segments[isrh->first_segment];
+
+#ifdef CONFIG_IPV6_SEG6_HMAC
+ if (sr_has_hmac(isrh)) {
+ struct net *net = dev_net(skb_dst(skb)->dev);
+
+ err = seg6_push_hmac(net, &hdr->saddr, isrh);
+ if (unlikely(err))
+ return err;
+ }
+#endif
+
+ skb_postpush_rcsum(skb, hdr, sizeof(struct ipv6hdr) + hdrlen);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(seg6_do_srh_inline);
+
+static int seg6_do_srh(struct sk_buff *skb)
+{
+ struct dst_entry *dst = skb_dst(skb);
+ struct seg6_iptunnel_encap *tinfo;
+ int proto, err = 0;
+
+ tinfo = seg6_encap_lwtunnel(dst->lwtstate);
+
+ switch (tinfo->mode) {
+ case SEG6_IPTUN_MODE_INLINE:
+ if (skb->protocol != htons(ETH_P_IPV6))
+ return -EINVAL;
+
+ err = seg6_do_srh_inline(skb, tinfo->srh);
+ if (err)
+ return err;
+ break;
+ case SEG6_IPTUN_MODE_ENCAP:
+ err = iptunnel_handle_offloads(skb, SKB_GSO_IPXIP6);
+ if (err)
+ return err;
+
+ if (skb->protocol == htons(ETH_P_IPV6))
+ proto = IPPROTO_IPV6;
+ else if (skb->protocol == htons(ETH_P_IP))
+ proto = IPPROTO_IPIP;
+ else
+ return -EINVAL;
+
+ err = seg6_do_srh_encap(skb, tinfo->srh, proto);
+ if (err)
+ return err;
+
+ skb_set_inner_transport_header(skb, skb_transport_offset(skb));
+ skb_set_inner_protocol(skb, skb->protocol);
+ skb->protocol = htons(ETH_P_IPV6);
+ break;
+ case SEG6_IPTUN_MODE_L2ENCAP:
+ if (!skb_mac_header_was_set(skb))
+ return -EINVAL;
+
+ if (pskb_expand_head(skb, skb->mac_len, 0, GFP_ATOMIC) < 0)
+ return -ENOMEM;
+
+ skb_mac_header_rebuild(skb);
+ skb_push(skb, skb->mac_len);
+
+ err = seg6_do_srh_encap(skb, tinfo->srh, NEXTHDR_NONE);
+ if (err)
+ return err;
+
+ skb->protocol = htons(ETH_P_IPV6);
+ break;
+ }
+
+ ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
+ skb_set_transport_header(skb, sizeof(struct ipv6hdr));
+
+ return 0;
+}
+
+static int seg6_input(struct sk_buff *skb)
+{
+ struct dst_entry *orig_dst = skb_dst(skb);
+ struct dst_entry *dst = NULL;
+ struct seg6_lwt *slwt;
+ int err;
+
+ err = seg6_do_srh(skb);
+ if (unlikely(err)) {
+ kfree_skb(skb);
+ return err;
+ }
+
+ slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);
+
+ preempt_disable();
+ dst = dst_cache_get(&slwt->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(&slwt->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 seg6_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 seg6_lwt *slwt;
+ int err = -EINVAL;
+
+ err = seg6_do_srh(skb);
+ if (unlikely(err))
+ goto drop;
+
+ slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);
+
+ preempt_disable();
+ dst = dst_cache_get(&slwt->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(&slwt->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 seg6_build_state(struct nlattr *nla,
+ unsigned int family, const void *cfg,
+ struct lwtunnel_state **ts,
+ struct netlink_ext_ack *extack)
+{
+ struct nlattr *tb[SEG6_IPTUNNEL_MAX + 1];
+ struct seg6_iptunnel_encap *tuninfo;
+ struct lwtunnel_state *newts;
+ int tuninfo_len, min_size;
+ struct seg6_lwt *slwt;
+ int err;
+
+ if (family != AF_INET && family != AF_INET6)
+ return -EINVAL;
+
+ err = nla_parse_nested(tb, SEG6_IPTUNNEL_MAX, nla,
+ seg6_iptunnel_policy, extack);
+
+ if (err < 0)
+ return err;
+
+ if (!tb[SEG6_IPTUNNEL_SRH])
+ return -EINVAL;
+
+ tuninfo = nla_data(tb[SEG6_IPTUNNEL_SRH]);
+ tuninfo_len = nla_len(tb[SEG6_IPTUNNEL_SRH]);
+
+ /* tuninfo must contain at least the iptunnel encap structure,
+ * the SRH and one segment
+ */
+ min_size = sizeof(*tuninfo) + sizeof(struct ipv6_sr_hdr) +
+ sizeof(struct in6_addr);
+ if (tuninfo_len < min_size)
+ return -EINVAL;
+
+ switch (tuninfo->mode) {
+ case SEG6_IPTUN_MODE_INLINE:
+ if (family != AF_INET6)
+ return -EINVAL;
+
+ break;
+ case SEG6_IPTUN_MODE_ENCAP:
+ break;
+ case SEG6_IPTUN_MODE_L2ENCAP:
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ /* verify that SRH is consistent */
+ if (!seg6_validate_srh(tuninfo->srh, tuninfo_len - sizeof(*tuninfo)))
+ return -EINVAL;
+
+ newts = lwtunnel_state_alloc(tuninfo_len + sizeof(*slwt));
+ if (!newts)
+ return -ENOMEM;
+
+ slwt = seg6_lwt_lwtunnel(newts);
+
+ err = dst_cache_init(&slwt->cache, GFP_ATOMIC);
+ if (err) {
+ kfree(newts);
+ return err;
+ }
+
+ memcpy(&slwt->tuninfo, tuninfo, tuninfo_len);
+
+ newts->type = LWTUNNEL_ENCAP_SEG6;
+ newts->flags |= LWTUNNEL_STATE_INPUT_REDIRECT;
+
+ if (tuninfo->mode != SEG6_IPTUN_MODE_L2ENCAP)
+ newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT;
+
+ newts->headroom = seg6_lwt_headroom(tuninfo);
+
+ *ts = newts;
+
+ return 0;
+}
+
+static void seg6_destroy_state(struct lwtunnel_state *lwt)
+{
+ dst_cache_destroy(&seg6_lwt_lwtunnel(lwt)->cache);
+}
+
+static int seg6_fill_encap_info(struct sk_buff *skb,
+ struct lwtunnel_state *lwtstate)
+{
+ struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);
+
+ if (nla_put_srh(skb, SEG6_IPTUNNEL_SRH, tuninfo))
+ return -EMSGSIZE;
+
+ return 0;
+}
+
+static int seg6_encap_nlsize(struct lwtunnel_state *lwtstate)
+{
+ struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);
+
+ return nla_total_size(SEG6_IPTUN_ENCAP_SIZE(tuninfo));
+}
+
+static int seg6_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
+{
+ struct seg6_iptunnel_encap *a_hdr = seg6_encap_lwtunnel(a);
+ struct seg6_iptunnel_encap *b_hdr = seg6_encap_lwtunnel(b);
+ int len = SEG6_IPTUN_ENCAP_SIZE(a_hdr);
+
+ if (len != SEG6_IPTUN_ENCAP_SIZE(b_hdr))
+ return 1;
+
+ return memcmp(a_hdr, b_hdr, len);
+}
+
+static const struct lwtunnel_encap_ops seg6_iptun_ops = {
+ .build_state = seg6_build_state,
+ .destroy_state = seg6_destroy_state,
+ .output = seg6_output,
+ .input = seg6_input,
+ .fill_encap = seg6_fill_encap_info,
+ .get_encap_size = seg6_encap_nlsize,
+ .cmp_encap = seg6_encap_cmp,
+ .owner = THIS_MODULE,
+};
+
+int __init seg6_iptunnel_init(void)
+{
+ return lwtunnel_encap_add_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);
+}
+
+void seg6_iptunnel_exit(void)
+{
+ lwtunnel_encap_del_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);
+}