diff options
Diffstat (limited to 'kernel/net/ipv6/ila.c')
| -rw-r--r-- | kernel/net/ipv6/ila.c | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/kernel/net/ipv6/ila.c b/kernel/net/ipv6/ila.c new file mode 100644 index 000000000..1a6852e1a --- /dev/null +++ b/kernel/net/ipv6/ila.c @@ -0,0 +1,229 @@ +#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"); |