--- /dev/null
+#include <linux/errno.h>
+#include <linux/ip.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/socket.h>
+#include <linux/types.h>
+#include <net/checksum.h>
+#include <net/ip.h>
+#include <net/ip6_fib.h>
+#include <net/lwtunnel.h>
+#include <net/protocol.h>
+#include <uapi/linux/ila.h>
+
+struct ila_params {
+ __be64 locator;
+ __be64 locator_match;
+ __wsum csum_diff;
+};
+
+static inline struct ila_params *ila_params_lwtunnel(
+ struct lwtunnel_state *lwstate)
+{
+ return (struct ila_params *)lwstate->data;
+}
+
+static inline __wsum compute_csum_diff8(const __be32 *from, const __be32 *to)
+{
+ __be32 diff[] = {
+ ~from[0], ~from[1], to[0], to[1],
+ };
+
+ return csum_partial(diff, sizeof(diff), 0);
+}
+
+static inline __wsum get_csum_diff(struct ipv6hdr *ip6h, struct ila_params *p)
+{
+ if (*(__be64 *)&ip6h->daddr == p->locator_match)
+ return p->csum_diff;
+ else
+ return compute_csum_diff8((__be32 *)&ip6h->daddr,
+ (__be32 *)&p->locator);
+}
+
+static void update_ipv6_locator(struct sk_buff *skb, struct ila_params *p)
+{
+ __wsum diff;
+ struct ipv6hdr *ip6h = ipv6_hdr(skb);
+ size_t nhoff = sizeof(struct ipv6hdr);
+
+ /* First update checksum */
+ switch (ip6h->nexthdr) {
+ case NEXTHDR_TCP:
+ if (likely(pskb_may_pull(skb, nhoff + sizeof(struct tcphdr)))) {
+ struct tcphdr *th = (struct tcphdr *)
+ (skb_network_header(skb) + nhoff);
+
+ diff = get_csum_diff(ip6h, p);
+ inet_proto_csum_replace_by_diff(&th->check, skb,
+ diff, true);
+ }
+ break;
+ case NEXTHDR_UDP:
+ if (likely(pskb_may_pull(skb, nhoff + sizeof(struct udphdr)))) {
+ struct udphdr *uh = (struct udphdr *)
+ (skb_network_header(skb) + nhoff);
+
+ if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
+ diff = get_csum_diff(ip6h, p);
+ inet_proto_csum_replace_by_diff(&uh->check, skb,
+ diff, true);
+ if (!uh->check)
+ uh->check = CSUM_MANGLED_0;
+ }
+ }
+ break;
+ case NEXTHDR_ICMP:
+ if (likely(pskb_may_pull(skb,
+ nhoff + sizeof(struct icmp6hdr)))) {
+ struct icmp6hdr *ih = (struct icmp6hdr *)
+ (skb_network_header(skb) + nhoff);
+
+ diff = get_csum_diff(ip6h, p);
+ inet_proto_csum_replace_by_diff(&ih->icmp6_cksum, skb,
+ diff, true);
+ }
+ break;
+ }
+
+ /* Now change destination address */
+ *(__be64 *)&ip6h->daddr = p->locator;
+}
+
+static int ila_output(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+ struct dst_entry *dst = skb_dst(skb);
+
+ if (skb->protocol != htons(ETH_P_IPV6))
+ goto drop;
+
+ update_ipv6_locator(skb, ila_params_lwtunnel(dst->lwtstate));
+
+ return dst->lwtstate->orig_output(net, sk, skb);
+
+drop:
+ kfree_skb(skb);
+ return -EINVAL;
+}
+
+static int ila_input(struct sk_buff *skb)
+{
+ struct dst_entry *dst = skb_dst(skb);
+
+ if (skb->protocol != htons(ETH_P_IPV6))
+ goto drop;
+
+ update_ipv6_locator(skb, ila_params_lwtunnel(dst->lwtstate));
+
+ return dst->lwtstate->orig_input(skb);
+
+drop:
+ kfree_skb(skb);
+ return -EINVAL;
+}
+
+static struct nla_policy ila_nl_policy[ILA_ATTR_MAX + 1] = {
+ [ILA_ATTR_LOCATOR] = { .type = NLA_U64, },
+};
+
+static int ila_build_state(struct net_device *dev, struct nlattr *nla,
+ unsigned int family, const void *cfg,
+ struct lwtunnel_state **ts)
+{
+ struct ila_params *p;
+ struct nlattr *tb[ILA_ATTR_MAX + 1];
+ size_t encap_len = sizeof(*p);
+ struct lwtunnel_state *newts;
+ const struct fib6_config *cfg6 = cfg;
+ int ret;
+
+ if (family != AF_INET6)
+ return -EINVAL;
+
+ ret = nla_parse_nested(tb, ILA_ATTR_MAX, nla,
+ ila_nl_policy);
+ if (ret < 0)
+ return ret;
+
+ if (!tb[ILA_ATTR_LOCATOR])
+ return -EINVAL;
+
+ newts = lwtunnel_state_alloc(encap_len);
+ if (!newts)
+ return -ENOMEM;
+
+ newts->len = encap_len;
+ p = ila_params_lwtunnel(newts);
+
+ p->locator = (__force __be64)nla_get_u64(tb[ILA_ATTR_LOCATOR]);
+
+ if (cfg6->fc_dst_len > sizeof(__be64)) {
+ /* Precompute checksum difference for translation since we
+ * know both the old locator and the new one.
+ */
+ p->locator_match = *(__be64 *)&cfg6->fc_dst;
+ p->csum_diff = compute_csum_diff8(
+ (__be32 *)&p->locator_match, (__be32 *)&p->locator);
+ }
+
+ newts->type = LWTUNNEL_ENCAP_ILA;
+ newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT |
+ LWTUNNEL_STATE_INPUT_REDIRECT;
+
+ *ts = newts;
+
+ return 0;
+}
+
+static int ila_fill_encap_info(struct sk_buff *skb,
+ struct lwtunnel_state *lwtstate)
+{
+ struct ila_params *p = ila_params_lwtunnel(lwtstate);
+
+ if (nla_put_u64(skb, ILA_ATTR_LOCATOR, (__force u64)p->locator))
+ goto nla_put_failure;
+
+ return 0;
+
+nla_put_failure:
+ return -EMSGSIZE;
+}
+
+static int ila_encap_nlsize(struct lwtunnel_state *lwtstate)
+{
+ /* No encapsulation overhead */
+ return 0;
+}
+
+static int ila_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
+{
+ struct ila_params *a_p = ila_params_lwtunnel(a);
+ struct ila_params *b_p = ila_params_lwtunnel(b);
+
+ return (a_p->locator != b_p->locator);
+}
+
+static const struct lwtunnel_encap_ops ila_encap_ops = {
+ .build_state = ila_build_state,
+ .output = ila_output,
+ .input = ila_input,
+ .fill_encap = ila_fill_encap_info,
+ .get_encap_size = ila_encap_nlsize,
+ .cmp_encap = ila_encap_cmp,
+};
+
+static int __init ila_init(void)
+{
+ return lwtunnel_encap_add_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
+}
+
+static void __exit ila_fini(void)
+{
+ lwtunnel_encap_del_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
+}
+
+module_init(ila_init);
+module_exit(ila_fini);
+MODULE_AUTHOR("Tom Herbert <tom@herbertland.com>");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff