+static int config_xfrm_policy(int sd, struct sock_args *args)
+{
+ struct xfrm_userpolicy_info policy = {};
+ int type = UDP_ENCAP_ESPINUDP;
+ int xfrm_af = IP_XFRM_POLICY;
+ int level = SOL_IP;
+
+ if (args->type != SOCK_DGRAM) {
+ log_error("Invalid socket type. Only DGRAM could be used for XFRM\n");
+ return 1;
+ }
+
+ policy.action = XFRM_POLICY_ALLOW;
+ policy.sel.family = args->version;
+ if (args->version == AF_INET6) {
+ xfrm_af = IPV6_XFRM_POLICY;
+ level = SOL_IPV6;
+ }
+
+ policy.dir = XFRM_POLICY_OUT;
+ if (setsockopt(sd, level, xfrm_af, &policy, sizeof(policy)) < 0)
+ return 1;
+
+ policy.dir = XFRM_POLICY_IN;
+ if (setsockopt(sd, level, xfrm_af, &policy, sizeof(policy)) < 0)
+ return 1;
+
+ if (setsockopt(sd, IPPROTO_UDP, UDP_ENCAP, &type, sizeof(type)) < 0) {
+ log_err_errno("Failed to set xfrm encap");
+ return 1;
+ }
+
+ return 0;
+}
+