xfrm security context support

In the Linux kernel, ipsec policy and SAs can include a
security context to support MAC networking. This feature
is often referred to as "labeled ipsec".

This patchset adds security context support into ip xfrm
such that a security context can be included when
add/delete/display SAs and policies with the ip command.
The user provides the security context when adding
SAs and policies. If a policy or SA contains a security
context, the changes allow the security context to be displayed.

For example,
ip xfrm state
src 10.1.1.6 dst 10.1.1.2
	proto esp spi 0x00000301 reqid 0 mode transport
	replay-window 0
	auth hmac(digest_null) 0x3078
	enc cbc(des3_ede) 0x6970763672656164796c6f676f33646573636263696e3031
	security context root:system_r:unconfined_t:s0

Please  let me know if all is ok with the patchset.
Thanks!!

regards,
Joy
Signed-off-by: Joy Latten <latten@austin.ibm.com>

ip/ipxfrm.c

@@ -850,6 +850,20 @@ void xfrm_state_info_print(struct xfrm_usersa_info *xsinfo,
 		xfrm_lifetime_print(&xsinfo->lft, &xsinfo->curlft, fp, buf);
 		xfrm_stats_print(&xsinfo->stats, fp, buf);
 	}
+
+	if (tb[XFRMA_SEC_CTX]) {
+		struct xfrm_user_sec_ctx *sctx;
+
+		fprintf(fp, "\tsecurity context ");
+
+		if (RTA_PAYLOAD(tb[XFRMA_SEC_CTX]) < sizeof(*sctx))
+			fprintf(fp, "(ERROR truncated)");
+
+		sctx = (struct xfrm_user_sec_ctx *)RTA_DATA(tb[XFRMA_SEC_CTX]);
+
+		fprintf(fp, "%s %s", (char *)(sctx + 1), _SL_);
+	}
+
 }
 
 void xfrm_policy_info_print(struct xfrm_userpolicy_info *xpinfo,
@@ -862,6 +876,20 @@ void xfrm_policy_info_print(struct xfrm_userpolicy_info *xpinfo,
 
 	xfrm_selector_print(&xpinfo->sel, preferred_family, fp, title);
 
+	if (tb[XFRMA_SEC_CTX]) {
+		struct xfrm_user_sec_ctx *sctx;
+
+		fprintf(fp, "\tsecurity context ");
+
+		if (RTA_PAYLOAD(tb[XFRMA_SEC_CTX]) < sizeof(*sctx))
+			fprintf(fp, "(ERROR truncated)");
+
+		sctx = (struct xfrm_user_sec_ctx *)RTA_DATA(tb[XFRMA_SEC_CTX]);
+
+		fprintf(fp, "%s ", (char *)(sctx + 1));
+		fprintf(fp, "%s", _SL_);
+	}
+
 	if (prefix)
 		STRBUF_CAT(buf, prefix);
 	STRBUF_CAT(buf, "\t");

ip/xfrm.h

@@ -154,5 +154,6 @@ int xfrm_reqid_parse(__u32 *reqid, int *argcp, char ***argvp);
 int xfrm_selector_parse(struct xfrm_selector *sel, int *argcp, char ***argvp);
 int xfrm_lifetime_cfg_parse(struct xfrm_lifetime_cfg *lft,
 			    int *argcp, char ***argvp);
-
+int xfrm_sctx_parse(char *ctxstr, char *context,
+		    struct xfrm_user_sec_ctx *sctx);
 #endif