path: root/net/tipc/netlink_compat.c

/*
 * Copyright (c) 2014, Ericsson AB
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the names of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "core.h"
#include "config.h"
#include "bearer.h"
#include "link.h"
#include "name_table.h"
#include "socket.h"
#include "node.h"
#include "net.h"
#include <net/genetlink.h>
#include <linux/tipc_config.h>

/* The legacy API had an artificial message length limit called
 * ULTRA_STRING_MAX_LEN.
 */
#define ULTRA_STRING_MAX_LEN 32768

#define TIPC_SKB_MAX TLV_SPACE(ULTRA_STRING_MAX_LEN)

#define REPLY_TRUNCATED "<truncated>\n"

struct tipc_nl_compat_msg {
	u16 cmd;
	int rep_type;
	int rep_size;
	int req_type;
	struct sk_buff *rep;
	struct tlv_desc *req;
	struct sock *dst_sk;
};

struct tipc_nl_compat_cmd_dump {
	int (*header)(struct tipc_nl_compat_msg *);
	int (*dumpit)(struct sk_buff *, struct netlink_callback *);
	int (*format)(struct tipc_nl_compat_msg *msg, struct nlattr **attrs);
};

struct tipc_nl_compat_cmd_doit {
	int (*doit)(struct sk_buff *skb, struct genl_info *info);
	int (*transcode)(struct sk_buff *skb, struct tipc_nl_compat_msg *msg);
};

static int tipc_skb_tailroom(struct sk_buff *skb)
{
	int tailroom;
	int limit;

	tailroom = skb_tailroom(skb);
	limit = TIPC_SKB_MAX - skb->len;

	if (tailroom < limit)
		return tailroom;

	return limit;
}

static int tipc_add_tlv(struct sk_buff *skb, u16 type, void *data, u16 len)
{
	struct tlv_desc *tlv = (struct tlv_desc *)skb_tail_pointer(skb);

	if (tipc_skb_tailroom(skb) < TLV_SPACE(len))
		return -EMSGSIZE;

	skb_put(skb, TLV_SPACE(len));
	tlv->tlv_type = htons(type);
	tlv->tlv_len = htons(TLV_LENGTH(len));
	if (len && data)
		memcpy(TLV_DATA(tlv), data, len);

	return 0;
}

static void tipc_tlv_init(struct sk_buff *skb, u16 type)
{
	struct tlv_desc *tlv = (struct tlv_desc *)skb->data;

	TLV_SET_LEN(tlv, 0);
	TLV_SET_TYPE(tlv, type);
	skb_put(skb, sizeof(struct tlv_desc));
}

static int tipc_tlv_sprintf(struct sk_buff *skb, const char *fmt, ...)
{
	int n;
	u16 len;
	u32 rem;
	char *buf;
	struct tlv_desc *tlv;
	va_list args;

	rem = tipc_skb_tailroom(skb);

	tlv = (struct tlv_desc *)skb->data;
	len = TLV_GET_LEN(tlv);
	buf = TLV_DATA(tlv) + len;

	va_start(args, fmt);
	n = vscnprintf(buf, rem, fmt, args);
	va_end(args);

	TLV_SET_LEN(tlv, n + len);
	skb_put(skb, n);

	return n;
}

static struct sk_buff *tipc_tlv_alloc(int size)
{
	int hdr_len;
	struct sk_buff *buf;

	size = TLV_SPACE(size);
	hdr_len = nlmsg_total_size(GENL_HDRLEN + TIPC_GENL_HDRLEN);

	buf = alloc_skb(hdr_len + size, GFP_KERNEL);
	if (!buf)
		return NULL;

	skb_reserve(buf, hdr_len);

	return buf;
}

static struct sk_buff *tipc_get_err_tlv(char *str)
{
	int str_len = strlen(str) + 1;
	struct sk_buff *buf;

	buf = tipc_tlv_alloc(TLV_SPACE(str_len));
	if (buf)
		tipc_add_tlv(buf, TIPC_TLV_ERROR_STRING, str, str_len);

	return buf;
}

static int __tipc_nl_compat_dumpit(struct tipc_nl_compat_cmd_dump *cmd,
				   struct tipc_nl_compat_m