[Swan-dev] clanger: ikev2_crypto_start

[D. Hugh Redelmeier]

In front of this function, the following comment appears:

/*
 * We need an md because the crypto continuation mechanism requires one
 * but we don't have one because we are not responding to an
 * incoming packet.
 * Solution: build a fake one.  How much do we need to fake?
 * Note: almost identical code appears at the end of aggr_outI1.
 *
 * XXX: This code does a crypto continue using an indirect dispatch
 * through the FSM.  Beyond making the code flow confusing is this
 * useful?  For instance, since SA_INIT has only one code path, it can
 * directly request ke and nonce with its dedicated continue function
 * - no need to jump through all these hoops.
 */

And yet, two cases look into the md to get a v2KE (key exchange
payload).  This seems contradictory.

Which is right?  Can someone improve the comments to reflect the
resolution.

	case STATE_V2_CREATE_R:
		/*
		 * ??? if we don't have an md (see above) why are we referencing it?
		 * ??? clang 6.0.0 warns md might be NULL
		 */
		if (md->chain[ISAKMP_NEXT_v2KE] != NULL) {
			request_ke_and_nonce("Child Responder KE and nonce nr",
					     st, st->st_oakley.ta_dh,
					     ikev2_crypto_continue);
		} else {
			request_nonce("Child Responder nonce nr",
				      st, ikev2_crypto_continue);
		}
		return STF_SUSPEND;

	case STATE_V2_REKEY_CHILD_R:
		/*
		 * ??? if we don't have an md (see above) why are we referencing it?
		 * ??? clang 6.0.0 warns md might be NULL
		 */
		if (md->chain[ISAKMP_NEXT_v2KE] != NULL) {
			request_ke_and_nonce("Child Rekey Responder KE and nonce nr",
					     st, st->st_oakley.ta_dh,
					     ikev2_crypto_continue);
		} else {
			request_nonce("Child Rekey Responder nonce nr",
				      st, ikev2_crypto_continue);
		}
		return STF_SUSPEND;