1#include <linux/errno.h>
  2#include <linux/ip.h>
  3#include <linux/kernel.h>
  4#include <linux/module.h>
  5#include <linux/skbuff.h>
  6#include <linux/socket.h>
  7#include <linux/types.h>
  8#include <net/checksum.h>
  9#include <net/ip.h>
 10#include <net/ip6_fib.h>
 11#include <net/lwtunnel.h>
 12#include <net/protocol.h>
 13#include <uapi/linux/ila.h>
 14#include "ila.h"
 15
 16static __wsum get_csum_diff(struct ipv6hdr *ip6h, struct ila_params *p)
 17{
 18	struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
 19
 20	if (p->locator_match.v64)
 21		return p->csum_diff;
 22	else
 23		return compute_csum_diff8((__be32 *)&iaddr->loc,
 24					  (__be32 *)&p->locator);
 25}
 26
 27static void ila_csum_do_neutral(struct ila_addr *iaddr,
 28				struct ila_params *p)
 29{
 30	__sum16 *adjust = (__force __sum16 *)&iaddr->ident.v16[3];
 31	__wsum diff, fval;
 32
 33	/* Check if checksum adjust value has been cached */
 34	if (p->locator_match.v64) {
 35		diff = p->csum_diff;
 36	} else {
 37		diff = compute_csum_diff8((__be32 *)&p->locator,
 38					  (__be32 *)iaddr);
 39	}
 40
 41	fval = (__force __wsum)(ila_csum_neutral_set(iaddr->ident) ?
 42			CSUM_NEUTRAL_FLAG : ~CSUM_NEUTRAL_FLAG);
 43
 44	diff = csum_add(diff, fval);
 45
 46	*adjust = ~csum_fold(csum_add(diff, csum_unfold(*adjust)));
 47
 48	/* Flip the csum-neutral bit. Either we are doing a SIR->ILA
 49	 * translation with ILA_CSUM_NEUTRAL_MAP as the csum_method
 50	 * and the C-bit is not set, or we are doing an ILA-SIR
 51	 * tranlsation and the C-bit is set.
 52	 */
 53	iaddr->ident.csum_neutral ^= 1;
 54}
 55
 56static void ila_csum_adjust_transport(struct sk_buff *skb,
 57				      struct ila_params *p)
 58{
 59	__wsum diff;
 60	struct ipv6hdr *ip6h = ipv6_hdr(skb);
 61	struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
 62	size_t nhoff = sizeof(struct ipv6hdr);
 63
 64	switch (ip6h->nexthdr) {
 65	case NEXTHDR_TCP:
 66		if (likely(pskb_may_pull(skb, nhoff + sizeof(struct tcphdr)))) {
 67			struct tcphdr *th = (struct tcphdr *)
 68					(skb_network_header(skb) + nhoff);
 69
 70			diff = get_csum_diff(ip6h, p);
 71			inet_proto_csum_replace_by_diff(&th->check, skb,
 72							diff, true);
 73		}
 74		break;
 75	case NEXTHDR_UDP:
 76		if (likely(pskb_may_pull(skb, nhoff + sizeof(struct udphdr)))) {
 77			struct udphdr *uh = (struct udphdr *)
 78					(skb_network_header(skb) + nhoff);
 79
 80			if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
 81				diff = get_csum_diff(ip6h, p);
 82				inet_proto_csum_replace_by_diff(&uh->check, skb,
 83								diff, true);
 84				if (!uh->check)
 85					uh->check = CSUM_MANGLED_0;
 86			}
 87		}
 88		break;
 89	case NEXTHDR_ICMP:
 90		if (likely(pskb_may_pull(skb,
 91					 nhoff + sizeof(struct icmp6hdr)))) {
 92			struct icmp6hdr *ih = (struct icmp6hdr *)
 93					(skb_network_header(skb) + nhoff);
 94
 95			diff = get_csum_diff(ip6h, p);
 96			inet_proto_csum_replace_by_diff(&ih->icmp6_cksum, skb,
 97							diff, true);
 98		}
 99		break;
100	}
101
102	/* Now change destination address */
103	iaddr->loc = p->locator;
104}
105
106void ila_update_ipv6_locator(struct sk_buff *skb, struct ila_params *p,
107			     bool set_csum_neutral)
108{
109	struct ipv6hdr *ip6h = ipv6_hdr(skb);
110	struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
111
112	/* First deal with the transport checksum */
113	if (ila_csum_neutral_set(iaddr->ident)) {
114		/* C-bit is set in the locator indicating that this
115		 * is a locator being translated to a SIR address.
116		 * Perform (receiver) checksum-neutral translation.
117		 */
118		if (!set_csum_neutral)
119			ila_csum_do_neutral(iaddr, p);
120	} else {
121		switch (p->csum_mode) {
122		case ILA_CSUM_ADJUST_TRANSPORT:
123			ila_csum_adjust_transport(skb, p);
124			break;
125		case ILA_CSUM_NEUTRAL_MAP:
126			ila_csum_do_neutral(iaddr, p);
127			break;
128		case ILA_CSUM_NO_ACTION:
129			break;
130		}
131	}
132
133	/* Now change destination address */
134	iaddr->loc = p->locator;
135}
136
137void ila_init_saved_csum(struct ila_params *p)
138{
139	if (!p->locator_match.v64)
140		return;
141
142	p->csum_diff = compute_csum_diff8(
143				(__be32 *)&p->locator,
144				(__be32 *)&p->locator_match);
145}
146
147static int __init ila_init(void)
148{
149	int ret;
150
151	ret = ila_lwt_init();
152
153	if (ret)
154		goto fail_lwt;
155
156	ret = ila_xlat_init();
157	if (ret)
158		goto fail_xlat;
159
160	return 0;
161fail_xlat:
162	ila_lwt_fini();
163fail_lwt:
164	return ret;
165}
166
167static void __exit ila_fini(void)
168{
169	ila_xlat_fini();
170	ila_lwt_fini();
171}
172
173module_init(ila_init);
174module_exit(ila_fini);
175MODULE_AUTHOR("Tom Herbert <tom@herbertland.com>");
176MODULE_LICENSE("GPL");