[PATCHv4 net-next-2.6 2/5] XFRM,IPv6: Introduce receive sockopts to access IRO remapped src/dst addresses

Arnaud Ebalard
2010-10-04T06:25:14Z

This patch introduces IRO recv sockopts, in order for userland processes
(e.g. UMIP) to access on-wire source or destination addresses found in
incoming (IPsec-protected) packets as they were before remapping by IRO.
The socket options are respectively IPV6_RECVIROSRC and IPV6_RECVIRODST.

Basically, the two recv socket options are similar in their purpose to
their generic RH2/HAO counterparts defined in RFC 3542 (IPV6_RECVIROSRC
<-> IPV6_RECVDSTOPTS, IPV6_RECVIRODST <-> IPV6_RECVRTHDR). They differ
on the following aspects:

- IRO reporting sockopts only work on incoming IPsec-protected packets
Userspace will never get IRO remapped address report for common
(non protected) packets.
- The receiver gets the original source/desination address (IRO
remapping) from its IPsec stack.
- as IRO sockopts only deal with addresses, no specific structure is
defined, i.e. struct in6_addr is used to pass info.

As we only interact with IPsec protected packets, struct sec_path is
used to carry information (addresses) for incoming packets that have
undergone remapping process.

Signed-off-by: Arnaud Ebalard <arno@natisbad.org>
---
include/linux/in6.h | 7 +++++++
include/linux/ipv6.h | 4 +++-
include/net/xfrm.h | 5 +++++
net/ipv6/datagram.c | 18 ++++++++++++++++++
net/ipv6/ipv6_sockglue.c | 26 ++++++++++++++++++++++++++
5 files changed, 59 insertions(+), 1 deletions(-)

diff --git a/include/linux/in6.h b/include/linux/in6.h
index c4bf46f..52a98ab 100644
--- a/include/linux/in6.h
+++ b/include/linux/in6.h
@@ -283,4 +283,11 @@ struct in6_flowlabel_req {
* MRT6_PIM 208
* (reserved) 209
*/
+
+/* IRO (IPsec Route Optimization) sockopts */
+#define IPV6_RECVIROSRC 74
+#define IPV6_IROSRC 75
+#define IPV6_RECVIRODST 76
+#define IPV6_IRODST 77
+
#endif
diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index e62683b..55289ee 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -341,7 +341,9 @@ struct ipv6_pinfo {
odstopts:1,
rxflow:1,
rxtclass:1,
- rxpmtu:1;
+ rxpmtu:1,
+ irosrc:1,
+ irodst:1;
} bits;
__u16 all;
} rxopt;
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 4f53532..e6a753c 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -909,6 +909,11 @@ struct sec_path {
atomic_t refcnt;
int len;
struct xfrm_state *xvec[XFRM_MAX_DEPTH];
+
+#ifdef CONFIG_XFRM_SUB_POLICY
+ struct in6_addr irosrc;
+ struct in6_addr irodst;
+#endif
};

static inline struct sec_path *
diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index ef371aa..2952c9e 100644
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -29,6 +29,7 @@
#include <net/transp_v6.h>
#include <net/ip6_route.h>
#include <net/tcp_states.h>
+#include <net/xfrm.h>

#include <linux/errqueue.h>
#include <asm/uaccess.h>
@@ -504,6 +505,23 @@ int datagram_recv_ctl(struct sock *sk, struct msghdr *msg, struct sk_buff *skb)
put_cmsg(msg, SOL_IPV6, IPV6_HOPOPTS, (ptr[1]+1)<<3, ptr);
}

+#ifdef CONFIG_XFRM_SUB_POLICY
+ /* If access to IRO-remapped source or destination address has been
+ * requested and it has indeed been remapped, provide the on-wire
+ * address to userland */
+ if (skb_sec_path(skb)) {
+ struct sec_path *sp = skb_sec_path(skb);
+
+ if (np->rxopt.bits.irosrc && !ipv6_addr_any(&sp->irosrc))
+ put_cmsg(msg, SOL_IPV6, IPV6_IROSRC,
+ sizeof(sp->irosrc), &sp->irosrc);
+
+ if (np->rxopt.bits.irodst && !ipv6_addr_any(&sp->irodst))
+ put_cmsg(msg, SOL_IPV6, IPV6_IRODST,
+ sizeof(sp->irodst), &sp->irodst);
+ }
+#endif
+
if (opt->lastopt &&
(np->rxopt.bits.dstopts || np->rxopt.bits.srcrt)) {
/*
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index a7f66bc..722a49f 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -302,6 +302,22 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
retv = 0;
break;

+#ifdef CONFIG_XFRM_SUB_POLICY
+ case IPV6_RECVIROSRC:
+ if (optlen < sizeof(int))
+ goto e_inval;
+ np->rxopt.bits.irosrc = valbool;
+ retv = 0;
+ break;
+
+ case IPV6_RECVIRODST:
+ if (optlen < sizeof(int))
+ goto e_inval;
+ np->rxopt.bits.irodst = valbool;
+ retv = 0;
+ break;
+#endif
+
case IPV6_2292DSTOPTS:
if (optlen < sizeof(int))
goto e_inval;
@@ -1056,6 +1072,16 @@ static int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
val = np->rxopt.bits.dstopts;
break;

+#ifdef CONFIG_XFRM_SUB_POLICY
+ case IPV6_RECVIROSRC:
+ val = np->rxopt.bits.irosrc;
+ break;
+
+ case IPV6_RECVIRODST:
+ val = np->rxopt.bits.irodst;
+ break;
+#endif
+
case IPV6_2292DSTOPTS:
val = np->rxopt.bits.odstopts;
break;
--
1.7.1