[2/9] pohmelfs: configuration interface.

[Evgeniy Polyakov]

This patch includes POHMELFS configuration interface based
on netlink kernel connector. This interface allows to create
configuration groups in the kerenel indexed by mount ID option.

Each configuration group can include multiple servers to work
with and various operation parameters.

Signed-off-by: Evgeniy Polyakov <zbr@xxxxxxxxxxx>

diff --git a/fs/pohmelfs/config.c b/fs/pohmelfs/config.c
new file mode 100644
index 0000000..941ab02
--- /dev/null
+++ b/fs/pohmelfs/config.c
@@ -0,0 +1,478 @@
+/*
+ * 2007+ Copyright (c) Evgeniy Polyakov <zbr@xxxxxxxxxxx>
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/connector.h>
+#include <linux/crypto.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/string.h>
+#include <linux/in.h>
+
+#include "netfs.h"
+
+/*
+ * Global configuration list.
+ * Each client can be asked to get one of them.
+ *
+ * Allows to provide remote server address (ipv4/v6/whatever), port
+ * and so on via kernel connector.
+ */
+
+static struct cb_id pohmelfs_cn_id = {.idx = POHMELFS_CN_IDX, .val = POHMELFS_CN_VAL};
+static LIST_HEAD(pohmelfs_config_list);
+static DEFINE_MUTEX(pohmelfs_config_lock);
+
+static inline int pohmelfs_config_eql(struct pohmelfs_ctl *sc, struct pohmelfs_ctl *ctl)
+{
+	if (sc->idx == ctl->idx && sc->type == ctl->type &&
+			sc->proto == ctl->proto &&
+			sc->addrlen == ctl->addrlen &&
+			!memcmp(&sc->addr, &ctl->addr, ctl->addrlen))
+		return 1;
+
+	return 0;
+}
+
+static struct pohmelfs_config_group *pohmelfs_find_config_group(unsigned int idx)
+{
+	struct pohmelfs_config_group *g, *group = NULL;
+
+	list_for_each_entry(g, &pohmelfs_config_list, group_entry) {
+		if (g->idx == idx) {
+			group = g;
+			break;
+		}
+	}
+
+	return group;
+}
+
+static struct pohmelfs_config_group *pohmelfs_find_create_config_group(unsigned int idx)
+{
+	struct pohmelfs_config_group *g;
+	
+	g = pohmelfs_find_config_group(idx);
+	if (g)
+		return g;
+
+	g = kzalloc(sizeof(struct pohmelfs_config_group), GFP_KERNEL);
+	if (!g)
+		return NULL;
+
+	INIT_LIST_HEAD(&g->config_list);
+	g->idx = idx;
+	g->num_entry = 0;
+
+	list_add_tail(&g->group_entry, &pohmelfs_config_list);
+
+	return g;
+}
+
+int pohmelfs_copy_config(struct pohmelfs_sb *psb)
+{
+	struct pohmelfs_config_group *g;
+	struct pohmelfs_config *c, *dst;
+	int err = -ENODEV;
+
+	mutex_lock(&pohmelfs_config_lock);
+
+	g = pohmelfs_find_config_group(psb->idx);
+	if (!g)
+		goto out_unlock;
+
+	/*
+	 * Run over all entries in given config group and try to crate and
+	 * initialize those, which do not exist in superblock list.
+	 * Skip all existing entries.
+	 */
+
+	list_for_each_entry(c, &g->config_list, config_entry) {
+		err = 0;
+		list_for_each_entry(dst, &psb->state_list, config_entry) {
+			if (pohmelfs_config_eql(&dst->state.ctl, &c->state.ctl)) {
+				err = -EEXIST;
+				break;
+			}
+		}
+
+		if (err)
+			continue;
+
+		dst = kzalloc(sizeof(struct pohmelfs_config), GFP_KERNEL);
+		if (!dst) {
+			err = -ENOMEM;
+			break;
+		}
+
+		memcpy(&dst->state.ctl, &c->state.ctl, sizeof(struct pohmelfs_ctl));
+
+		list_add_tail(&dst->config_entry, &psb->state_list);
+
+		err = pohmelfs_state_init_one(psb, dst);
+		if (err) {
+			list_del(&dst->config_entry);
+			kfree(dst);
+		}
+
+		err = 0;
+	}
+
+out_unlock:
+	mutex_unlock(&pohmelfs_config_lock);
+
+	return err;
+}
+
+int pohmelfs_copy_crypto(struct pohmelfs_sb *psb)
+{
+	struct pohmelfs_config_group *g;
+	int err = -ENOENT;
+
+	mutex_lock(&pohmelfs_config_lock);
+	g = pohmelfs_find_config_group(psb->idx);
+	if (!g)
+		goto err_out_exit;
+
+	if (g->hash_string) {
+		err = -ENOMEM;
+		psb->hash_string = kstrdup(g->hash_string, GFP_KERNEL);
+		if (!psb->hash_string)
+			goto err_out_exit;
+		psb->hash_strlen = g->hash_strlen;
+	}
+
+	if (g->cipher_string) {
+		psb->cipher_string = kstrdup(g->cipher_string, GFP_KERNEL);
+		if (!psb->cipher_string)
+			goto err_out_free_hash_string;
+		psb->cipher_strlen = g->cipher_strlen;
+	}
+
+	if (g->hash_keysize) {
+		psb->hash_key = kmalloc(g->hash_keysize, GFP_KERNEL);
+		if (!psb->hash_key)
+			goto err_out_free_cipher_string;
+		memcpy(psb->hash_key, g->hash_key, g->hash_keysize);
+		psb->hash_keysize = g->hash_keysize;
+	}
+
+	if (g->cipher_keysize) {
+		psb->cipher_key = kmalloc(g->cipher_keysize, GFP_KERNEL);
+		if (!psb->cipher_key)
+			goto err_out_free_hash;
+		memcpy(psb->cipher_key, g->cipher_key, g->cipher_keysize);
+		psb->cipher_keysize = g->cipher_keysize;
+	}
+
+	mutex_unlock(&pohmelfs_config_lock);
+
+	return 0;
+
+err_out_free_hash:
+	kfree(psb->hash_key);
+err_out_free_cipher_string:
+	kfree(psb->cipher_string);
+err_out_free_hash_string:
+	kfree(psb->hash_string);
+err_out_exit:
+	mutex_unlock(&pohmelfs_config_lock);
+	return err;
+}
+
+static int pohmelfs_send_reply(int err, int msg_num, int action, struct cn_msg *msg, struct pohmelfs_ctl *ctl)
+{
+	struct pohmelfs_cn_ack *ack;
+
+	ack = kmalloc(sizeof(struct pohmelfs_cn_ack), GFP_KERNEL);
+	if (!ack)
+		return -ENOMEM;
+
+	memset(ack, 0, sizeof(struct pohmelfs_cn_ack));
+	memcpy(&ack->msg, msg, sizeof(struct cn_msg));
+
+	if (action == POHMELFS_CTLINFO_ACK)
+		memcpy(&ack->ctl, ctl, sizeof(struct pohmelfs_ctl));
+
+	ack->msg.len = sizeof(struct pohmelfs_cn_ack) - sizeof(struct cn_msg);
+	ack->msg.ack = msg->ack + 1;
+	ack->error = err;
+	ack->msg_num = msg_num;
+
+	cn_netlink_send(&ack->msg, 0, GFP_KERNEL);
+	kfree(ack);
+	return 0;
+}
+
+static int pohmelfs_cn_disp(struct cn_msg *msg)
+{
+	struct pohmelfs_config_group *g;
+	struct pohmelfs_ctl *ctl = (struct pohmelfs_ctl *)msg->data;
+	struct pohmelfs_config *c, *tmp;
+	int err = 0, i = 1;
+
+	if (msg->len != sizeof(struct pohmelfs_ctl))
+		return -EBADMSG;
+
+	mutex_lock(&pohmelfs_config_lock);
+
+	g = pohmelfs_find_config_group(ctl->idx);
+	if (!g) {
+		pohmelfs_send_reply(err, 0, POHMELFS_NOINFO_ACK, msg, NULL);
+		goto out_unlock;
+	}
+
+	list_for_each_entry_safe(c, tmp, &g->config_list, config_entry) {
+		struct pohmelfs_ctl *sc = &c->state.ctl;
+		if (pohmelfs_send_reply(err, g->num_entry - i, POHMELFS_CTLINFO_ACK, msg, sc)) {
+			err = -ENOMEM;
+			goto out_unlock;
+		}
+		i += 1;
+	}
+
+out_unlock:
+        mutex_unlock(&pohmelfs_config_lock);
+        return err;
+}
+
+static int pohmelfs_cn_ctl(struct cn_msg *msg, int action)
+{
+	struct pohmelfs_config_group *g;
+	struct pohmelfs_ctl *ctl = (struct pohmelfs_ctl *)msg->data;
+	struct pohmelfs_config *c, *tmp;
+	int err = 0;
+
+	if (msg->len != sizeof(struct pohmelfs_ctl))
+		return -EBADMSG;
+
+	mutex_lock(&pohmelfs_config_lock);
+
+	g = pohmelfs_find_create_config_group(ctl->idx);
+	if (!g) {
+		err = -ENOMEM;
+		goto out_unlock;
+	}
+
+	list_for_each_entry_safe(c, tmp, &g->config_list, config_entry) {
+		struct pohmelfs_ctl *sc = &c->state.ctl;
+
+		if (pohmelfs_config_eql(sc, ctl)) {
+			if (action == POHMELFS_FLAGS_ADD) {
+				err = -EEXIST;
+				goto out_unlock;
+			} else if (action == POHMELFS_FLAGS_DEL) {
+				list_del(&c->config_entry);
+				g->num_entry--;
+				kfree(c);
+				goto out_unlock;
+			} else {
+				err = -EEXIST;
+				goto out_unlock;
+			}
+		}
+	}
+	if (action == POHMELFS_FLAGS_DEL) {
+		err = -EBADMSG;
+		goto out_unlock;
+	}
+
+	c = kzalloc(sizeof(struct pohmelfs_config), GFP_KERNEL);
+	if (!c) {
+		err = -ENOMEM;
+		goto out_unlock;
+	}
+	memcpy(&c->state.ctl, ctl, sizeof(struct pohmelfs_ctl));
+	g->num_entry++;
+	list_add_tail(&c->config_entry, &g->config_list);
+
+out_unlock:
+	mutex_unlock(&pohmelfs_config_lock);
+	if (pohmelfs_send_reply(err, 0, POHMELFS_NOINFO_ACK, msg, NULL))
+		err = -ENOMEM;
+
+	return err;
+}
+
+static int pohmelfs_crypto_hash_init(struct pohmelfs_config_group *g, struct pohmelfs_crypto *c)
+{
+	char *algo = (char *)c->data;
+	u8 *key = (u8 *)(algo + c->strlen);
+
+	if (g->hash_string)
+		return -EEXIST;
+
+	g->hash_string = kstrdup(algo, GFP_KERNEL);
+	if (!g->hash_string)
+		return -ENOMEM;
+	g->hash_strlen = c->strlen;
+	g->hash_keysize = c->keysize;
+
+	g->hash_key = kmalloc(c->keysize, GFP_KERNEL);
+	if (!g->hash_key) {
+		kfree(g->hash_string);
+		return -ENOMEM;
+	}
+
+	memcpy(g->hash_key, key, c->keysize);
+
+	return 0;
+}
+
+static int pohmelfs_crypto_cipher_init(struct pohmelfs_config_group *g, struct pohmelfs_crypto *c)
+{
+	char *algo = (char *)c->data;
+	u8 *key = (u8 *)(algo + c->strlen);
+
+	if (g->cipher_string)
+		return -EEXIST;
+
+	g->cipher_string = kstrdup(algo, GFP_KERNEL);
+	if (!g->cipher_string)
+		return -ENOMEM;
+	g->cipher_strlen = c->strlen;
+	g->cipher_keysize = c->keysize;
+
+	g->cipher_key = kmalloc(c->keysize, GFP_KERNEL);
+	if (!g->cipher_key) {
+		kfree(g->cipher_string);
+		return -ENOMEM;
+	}
+
+	memcpy(g->cipher_key, key, c->keysize);
+
+	return 0;
+}
+
+
+static int pohmelfs_cn_crypto(struct cn_msg *msg)
+{
+	struct pohmelfs_crypto *crypto = (struct pohmelfs_crypto *)msg->data;
+	struct pohmelfs_config_group *g;
+	int err = 0;
+
+	dprintk("%s: idx: %u, strlen: %u, type: %u, keysize: %u, algo: %s.\n",
+			__func__, crypto->idx, crypto->strlen, crypto->type,
+			crypto->keysize, (char *)crypto->data);
+
+	mutex_lock(&pohmelfs_config_lock);
+	g = pohmelfs_find_create_config_group(crypto->idx);
+	if (!g) {
+		err = -ENOMEM;
+		goto out_unlock;
+	}
+
+	switch (crypto->type) {
+		case POHMELFS_CRYPTO_HASH:
+			err = pohmelfs_crypto_hash_init(g, crypto);
+			break;
+		case POHMELFS_CRYPTO_CIPHER:
+			err = pohmelfs_crypto_cipher_init(g, crypto);
+			break;
+		default:
+			err = -ENOTSUPP;
+			break;
+	}
+
+out_unlock:
+	mutex_unlock(&pohmelfs_config_lock);
+	if (pohmelfs_send_reply(err, 0, POHMELFS_NOINFO_ACK, msg, NULL))
+		err = -ENOMEM;
+
+	return err;
+}
+
+static void pohmelfs_cn_callback(void *data)
+{
+	struct cn_msg *msg = data;
+	int err;
+	
+	switch (msg->flags) {
+		case POHMELFS_FLAGS_ADD:
+			err = pohmelfs_cn_ctl(msg, POHMELFS_FLAGS_ADD);
+			break;
+		case POHMELFS_FLAGS_DEL:
+			err = pohmelfs_cn_ctl(msg, POHMELFS_FLAGS_DEL);
+			break;
+		case POHMELFS_FLAGS_SHOW:
+			err = pohmelfs_cn_disp(msg);
+			break;
+		case POHMELFS_FLAGS_CRYPTO:
+			err = pohmelfs_cn_crypto(msg);
+			break;
+		default:
+			err = -ENOSYS;
+			break;
+	}
+}
+
+int pohmelfs_config_check(struct pohmelfs_config *config, int idx)
+{
+	struct pohmelfs_ctl *ctl = &config->state.ctl;
+	struct pohmelfs_config *tmp;
+	int err = -ENOENT;
+	struct pohmelfs_ctl *sc;
+	struct pohmelfs_config_group *g;
+
+	mutex_lock(&pohmelfs_config_lock);
+
+	g = pohmelfs_find_config_group(ctl->idx);
+	if (g) {
+		list_for_each_entry(tmp, &g->config_list, config_entry) {
+			sc = &tmp->state.ctl;
+
+			if (pohmelfs_config_eql(sc, ctl)) {
+				err = 0;
+				break;
+			}
+		}
+	}
+
+	mutex_unlock(&pohmelfs_config_lock);
+
+	return err;
+}
+
+int __init pohmelfs_config_init(void)
+{
+	return cn_add_callback(&pohmelfs_cn_id, "pohmelfs", pohmelfs_cn_callback);
+}
+
+void pohmelfs_config_exit(void)
+{
+	struct pohmelfs_config *c, *tmp;
+	struct pohmelfs_config_group *g, *gtmp;
+
+	cn_del_callback(&pohmelfs_cn_id);
+
+	mutex_lock(&pohmelfs_config_lock);
+	list_for_each_entry_safe(g, gtmp, &pohmelfs_config_list, group_entry) {
+		list_for_each_entry_safe(c, tmp, &g->config_list, config_entry) {
+			list_del(&c->config_entry);
+			kfree(c);
+		}
+
+		list_del(&g->group_entry);
+
+		if (g->hash_string)
+			kfree(g->hash_string);
+
+		if (g->cipher_string)
+			kfree(g->cipher_string);
+
+		kfree(g);
+	}
+	mutex_unlock(&pohmelfs_config_lock);
+}
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