feat.c

linux 内核源代码

	}

	switch (type) {
	case DCCPO_CHANGE_L:
		opt->dccpop_type = DCCPO_CONFIRM_R;
		break;
	case DCCPO_CHANGE_R:
		opt->dccpop_type = DCCPO_CONFIRM_L;
		break;
	default:
		DCCP_WARN("invalid type %d\n", type);
		kfree(opt);
		return;
	}
	opt->dccpop_feat = feature;
	opt->dccpop_val	 = NULL;
	opt->dccpop_len	 = 0;

	/* change feature */
	dccp_pr_debug("Empty %s(%d)\n", dccp_feat_typename(type), feature);

	list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
}

static void dccp_feat_flush_confirm(struct sock *sk)
{
	struct dccp_minisock *dmsk = dccp_msk(sk);
	/* Check if there is anything to confirm in the first place */
	int yes = !list_empty(&dmsk->dccpms_conf);

	if (!yes) {
		struct dccp_opt_pend *opt;

		list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
			if (opt->dccpop_conf) {
				yes = 1;
				break;
			}
		}
	}

	if (!yes)
		return;

	/* OK there is something to confirm... */
	/* XXX check if packet is in flight?  Send delayed ack?? */
	if (sk->sk_state == DCCP_OPEN)
		dccp_send_ack(sk);
}

int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
{
	int rc;

	dccp_feat_debug(type, feature, *val);

	/* figure out if it's SP or NN feature */
	switch (feature) {
	/* deal with SP features */
	case DCCPF_CCID:
		rc = dccp_feat_sp(sk, type, feature, val, len);
		break;

	/* deal with NN features */
	case DCCPF_ACK_RATIO:
		rc = dccp_feat_nn(sk, type, feature, val, len);
		break;

	/* XXX implement other features */
	default:
		dccp_pr_debug("UNIMPLEMENTED: not handling %s(%d, ...)\n",
			      dccp_feat_typename(type), feature);
		rc = -EFAULT;
		break;
	}

	/* check if there were problems changing features */
	if (rc) {
		/* If we don't agree on SP, we sent a confirm for old value.
		 * However we propagate rc to caller in case option was
		 * mandatory
		 */
		if (rc != DCCP_FEAT_SP_NOAGREE)
			dccp_feat_empty_confirm(dccp_msk(sk), type, feature);
	}

	/* generate the confirm [if required] */
	dccp_feat_flush_confirm(sk);

	return rc;
}

EXPORT_SYMBOL_GPL(dccp_feat_change_recv);

int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
			   u8 *val, u8 len)
{
	u8 t;
	struct dccp_opt_pend *opt;
	struct dccp_minisock *dmsk = dccp_msk(sk);
	int found = 0;
	int all_confirmed = 1;

	dccp_feat_debug(type, feature, *val);

	/* locate our change request */
	switch (type) {
	case DCCPO_CONFIRM_L: t = DCCPO_CHANGE_R; break;
	case DCCPO_CONFIRM_R: t = DCCPO_CHANGE_L; break;
	default:	      DCCP_WARN("invalid type %d\n", type);
			      return 1;

	}
	/* XXX sanity check feature value */

	list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
		if (!opt->dccpop_conf && opt->dccpop_type == t &&
		    opt->dccpop_feat == feature) {
			found = 1;
			dccp_pr_debug("feature %d found\n", opt->dccpop_feat);

			/* XXX do sanity check */

			opt->dccpop_conf = 1;

			/* We got a confirmation---change the option */
			dccp_feat_update(sk, opt->dccpop_type,
					 opt->dccpop_feat, *val);

			/* XXX check the return value of dccp_feat_update */
			break;
		}

		if (!opt->dccpop_conf)
			all_confirmed = 0;
	}

	/* fix re-transmit timer */
	/* XXX gotta make sure that no option negotiation occurs during
	 * connection shutdown.  Consider that the CLOSEREQ is sent and timer is
	 * on.  if all options are confirmed it might kill timer which should
	 * remain alive until close is received.
	 */
	if (all_confirmed) {
		dccp_pr_debug("clear feat negotiation timer %p\n", sk);
		inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
	}

	if (!found)
		dccp_pr_debug("%s(%d, ...) never requested\n",
			      dccp_feat_typename(type), feature);
	return 0;
}

EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv);

void dccp_feat_clean(struct dccp_minisock *dmsk)
{
	struct dccp_opt_pend *opt, *next;

	list_for_each_entry_safe(opt, next, &dmsk->dccpms_pending,
				 dccpop_node) {
		BUG_ON(opt->dccpop_val == NULL);
		kfree(opt->dccpop_val);

		if (opt->dccpop_sc != NULL) {
			BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
			kfree(opt->dccpop_sc->dccpoc_val);
			kfree(opt->dccpop_sc);
		}

		kfree(opt);
	}
	INIT_LIST_HEAD(&dmsk->dccpms_pending);

	list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
		BUG_ON(opt == NULL);
		if (opt->dccpop_val != NULL)
			kfree(opt->dccpop_val);
		kfree(opt);
	}
	INIT_LIST_HEAD(&dmsk->dccpms_conf);
}

EXPORT_SYMBOL_GPL(dccp_feat_clean);

/* this is to be called only when a listening sock creates its child.  It is
 * assumed by the function---the confirm is not duplicated, but rather it is
 * "passed on".
 */
int dccp_feat_clone(struct sock *oldsk, struct sock *newsk)
{
	struct dccp_minisock *olddmsk = dccp_msk(oldsk);
	struct dccp_minisock *newdmsk = dccp_msk(newsk);
	struct dccp_opt_pend *opt;
	int rc = 0;

	INIT_LIST_HEAD(&newdmsk->dccpms_pending);
	INIT_LIST_HEAD(&newdmsk->dccpms_conf);

	list_for_each_entry(opt, &olddmsk->dccpms_pending, dccpop_node) {
		struct dccp_opt_pend *newopt;
		/* copy the value of the option */
		u8 *val = kmemdup(opt->dccpop_val, opt->dccpop_len, GFP_ATOMIC);

		if (val == NULL)
			goto out_clean;

		newopt = kmemdup(opt, sizeof(*newopt), GFP_ATOMIC);
		if (newopt == NULL) {
			kfree(val);
			goto out_clean;
		}

		/* insert the option */
		newopt->dccpop_val = val;
		list_add_tail(&newopt->dccpop_node, &newdmsk->dccpms_pending);

		/* XXX what happens with backlogs and multiple connections at
		 * once...
		 */
		/* the master socket no longer needs to worry about confirms */
		opt->dccpop_sc = NULL; /* it's not a memleak---new socket has it */

		/* reset state for a new socket */
		opt->dccpop_conf = 0;
	}

	/* XXX not doing anything about the conf queue */

out:
	return rc;

out_clean:
	dccp_feat_clean(newdmsk);
	rc = -ENOMEM;
	goto out;
}

EXPORT_SYMBOL_GPL(dccp_feat_clone);

static int __dccp_feat_init(struct dccp_minisock *dmsk, u8 type, u8 feat,
			    u8 *val, u8 len)
{
	int rc = -ENOMEM;
	u8 *copy = kmemdup(val, len, GFP_KERNEL);

	if (copy != NULL) {
		rc = dccp_feat_change(dmsk, type, feat, copy, len, GFP_KERNEL);
		if (rc)
			kfree(copy);
	}
	return rc;
}

int dccp_feat_init(struct dccp_minisock *dmsk)
{
	int rc;

	INIT_LIST_HEAD(&dmsk->dccpms_pending);
	INIT_LIST_HEAD(&dmsk->dccpms_conf);

	/* CCID L */
	rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_CCID,
			      &dmsk->dccpms_tx_ccid, 1);
	if (rc)
		goto out;

	/* CCID R */
	rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_R, DCCPF_CCID,
			      &dmsk->dccpms_rx_ccid, 1);
	if (rc)
		goto out;

	/* Ack ratio */
	rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_ACK_RATIO,
			      &dmsk->dccpms_ack_ratio, 1);
out:
	return rc;
}

EXPORT_SYMBOL_GPL(dccp_feat_init);

#ifdef CONFIG_IP_DCCP_DEBUG
const char *dccp_feat_typename(const u8 type)
{
	switch(type) {
	case DCCPO_CHANGE_L:  return("ChangeL");
	case DCCPO_CONFIRM_L: return("ConfirmL");
	case DCCPO_CHANGE_R:  return("ChangeR");
	case DCCPO_CONFIRM_R: return("ConfirmR");
	/* the following case must not appear in feature negotation  */
	default:	      dccp_pr_debug("unknown type %d [BUG!]\n", type);
	}
	return NULL;
}

EXPORT_SYMBOL_GPL(dccp_feat_typename);

const char *dccp_feat_name(const u8 feat)
{
	static const char *feature_names[] = {
		[DCCPF_RESERVED]	= "Reserved",
		[DCCPF_CCID]		= "CCID",
		[DCCPF_SHORT_SEQNOS]	= "Allow Short Seqnos",
		[DCCPF_SEQUENCE_WINDOW]	= "Sequence Window",
		[DCCPF_ECN_INCAPABLE]	= "ECN Incapable",
		[DCCPF_ACK_RATIO]	= "Ack Ratio",
		[DCCPF_SEND_ACK_VECTOR]	= "Send ACK Vector",
		[DCCPF_SEND_NDP_COUNT]	= "Send NDP Count",
		[DCCPF_MIN_CSUM_COVER]	= "Min. Csum Coverage",
		[DCCPF_DATA_CHECKSUM]	= "Send Data Checksum",
	};
	if (feat >= DCCPF_MIN_CCID_SPECIFIC)
		return "CCID-specific";

	if (dccp_feat_is_reserved(feat))
		return feature_names[DCCPF_RESERVED];

	return feature_names[feat];
}

EXPORT_SYMBOL_GPL(dccp_feat_name);
#endif /* CONFIG_IP_DCCP_DEBUG */