/*

 *   mnlg.c	Generic Netlink helpers for libmnl

 *

 *              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.

 *

 * Authors:     Jiri Pirko <jiri@mellanox.com>

 */

#include <stdlib.h>

#include <stdbool.h>

#include <string.h>

#include <errno.h>

#include <unistd.h>

#include <time.h>

#include <libmnl/libmnl.h>

#include <linux/genetlink.h>

#include "libnetlink.h"

#include "utils.h"

#include "mnlg.h"

struct mnlg_socket {

	struct mnl_socket *nl;

	char *buf;

	uint32_t id;

	uint8_t version;

	unsigned int seq;

	unsigned int portid;

};

static struct nlmsghdr *__mnlg_msg_prepare(struct mnlg_socket *nlg, uint8_t cmd,

					   uint16_t flags, uint32_t id,

					   uint8_t version)

{

	struct nlmsghdr *nlh;

	struct genlmsghdr *genl;

	nlh = mnl_nlmsg_put_header(nlg->buf);

	nlh->nlmsg_type	= id;

	nlh->nlmsg_flags = flags;

	nlg->seq = time(NULL);

	nlh->nlmsg_seq = nlg->seq;

	genl = mnl_nlmsg_put_extra_header(nlh, sizeof(struct genlmsghdr));

	genl->cmd = cmd;

	genl->version = version;

	return nlh;

}

struct nlmsghdr *mnlg_msg_prepare(struct mnlg_socket *nlg, uint8_t cmd,

				  uint16_t flags)

{

	return __mnlg_msg_prepare(nlg, cmd, flags, nlg->id, nlg->version);

}

int mnlg_socket_send(struct mnlg_socket *nlg, const struct nlmsghdr *nlh)

{

	return mnl_socket_sendto(nlg->nl, nlh, nlh->nlmsg_len);

}

static int mnlg_cb_noop(const struct nlmsghdr *nlh, void *data)

{

	return MNL_CB_OK;

}

static int mnlg_cb_error(const struct nlmsghdr *nlh, void *data)

{

	const struct nlmsgerr *err = mnl_nlmsg_get_payload(nlh);

	/* Netlink subsystems returns the errno value with different signess */

	if (err->error < 0)

		errno = -err->error;

	else

		errno = err->error;

	if (nl_dump_ext_ack(nlh, NULL))

		return MNL_CB_ERROR;

	return err->error == 0 ? MNL_CB_STOP : MNL_CB_ERROR;

}

static int mnlg_cb_stop(const struct nlmsghdr *nlh, void *data)

{

	int len = *(int *)NLMSG_DATA(nlh);

	if (len < 0) {

		errno = -len;

		nl_dump_ext_ack_done(nlh, len);

		return MNL_CB_ERROR;

	}

	return MNL_CB_STOP;

}

static mnl_cb_t mnlg_cb_array[NLMSG_MIN_TYPE] = {

	[NLMSG_NOOP]	= mnlg_cb_noop,

	[NLMSG_ERROR]	= mnlg_cb_error,

	[NLMSG_DONE]	= mnlg_cb_stop,

	[NLMSG_OVERRUN]	= mnlg_cb_noop,

};

int mnlg_socket_recv_run(struct mnlg_socket *nlg, mnl_cb_t data_cb, void *data)

{

	int err;

	do {

		err = mnl_socket_recvfrom(nlg->nl, nlg->buf,

					  MNL_SOCKET_BUFFER_SIZE);

		if (err <= 0)

			break;

		err = mnl_cb_run2(nlg->buf, err, nlg->seq, nlg->portid,

				  data_cb, data, mnlg_cb_array,

				  ARRAY_SIZE(mnlg_cb_array));

	} while (err > 0);

	return err;

}

struct group_info {

	bool found;

	uint32_t id;

	const char *name;

};

static int parse_mc_grps_cb(const struct nlattr *attr, void *data)

{

	const struct nlattr **tb = data;

	int type = mnl_attr_get_type(attr);

	if (mnl_attr_type_valid(attr, CTRL_ATTR_MCAST_GRP_MAX) < 0)

		return MNL_CB_OK;

	switch (type) {

	case CTRL_ATTR_MCAST_GRP_ID:

		if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)

			return MNL_CB_ERROR;

		break;

	case CTRL_ATTR_MCAST_GRP_NAME:

		if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)

			return MNL_CB_ERROR;

		break;

	}

	tb[type] = attr;

	return MNL_CB_OK;

}

static void parse_genl_mc_grps(struct nlattr *nested,

			       struct group_info *group_info)

{

	struct nlattr *pos;

	const char *name;

	mnl_attr_for_each_nested(pos, nested) {

		struct nlattr *tb[CTRL_ATTR_MCAST_GRP_MAX + 1] = {};

		mnl_attr_parse_nested(pos, parse_mc_grps_cb, tb);

		if (!tb[CTRL_ATTR_MCAST_GRP_NAME] ||

		    !tb[CTRL_ATTR_MCAST_GRP_ID])

			continue;

		name = mnl_attr_get_str(tb[CTRL_ATTR_MCAST_GRP_NAME]);

		if (strcmp(name, group_info->name) != 0)

			continue;

		group_info->id = mnl_attr_get_u32(tb[CTRL_ATTR_MCAST_GRP_ID]);

		group_info->found = true;

	}

}

static int get_group_id_attr_cb(const struct nlattr *attr, void *data)

{

	const struct nlattr **tb = data;

	int type = mnl_attr_get_type(attr);

	if (mnl_attr_type_valid(attr, CTRL_ATTR_MAX) < 0)

		return MNL_CB_ERROR;

	if (type == CTRL_ATTR_MCAST_GROUPS &&

	    mnl_attr_validate(attr, MNL_TYPE_NESTED) < 0)

		return MNL_CB_ERROR;

	tb[type] = attr;

	return MNL_CB_OK;

}

static int get_group_id_cb(const struct nlmsghdr *nlh, void *data)

{

	struct group_info *group_info = data;

	struct nlattr *tb[CTRL_ATTR_MAX + 1] = {};

	struct genlmsghdr *genl = mnl_nlmsg_get_payload(nlh);

	mnl_attr_parse(nlh, sizeof(*genl), get_group_id_attr_cb, tb);

	if (!tb[CTRL_ATTR_MCAST_GROUPS])

		return MNL_CB_ERROR;

	parse_genl_mc_grps(tb[CTRL_ATTR_MCAST_GROUPS], group_info);

	return MNL_CB_OK;

}

int mnlg_socket_group_add(struct mnlg_socket *nlg, const char *group_name)

{

	struct nlmsghdr *nlh;

	struct group_info group_info;

	int err;

	nlh = __mnlg_msg_prepare(nlg, CTRL_CMD_GETFAMILY,

				 NLM_F_REQUEST | NLM_F_ACK, GENL_ID_CTRL, 1);

	mnl_attr_put_u16(nlh, CTRL_ATTR_FAMILY_ID, nlg->id);

	err = mnlg_socket_send(nlg, nlh);

	if (err < 0)

		return err;

	group_info.found = false;

	group_info.name = group_name;

	err = mnlg_socket_recv_run(nlg, get_group_id_cb, &group_info);

	if (err < 0)

		return err;

	if (!group_info.found) {

		errno = ENOENT;

		return -1;

	}

	err = mnl_socket_setsockopt(nlg->nl, NETLINK_ADD_MEMBERSHIP,

				    &group_info.id, sizeof(group_info.id));

	if (err < 0)

		return err;

	return 0;

}

static int get_family_id_attr_cb(const struct nlattr *attr, void *data)

{

	const struct nlattr **tb = data;

	int type = mnl_attr_get_type(attr);

	if (mnl_attr_type_valid(attr, CTRL_ATTR_MAX) < 0)

		return MNL_CB_ERROR;

	if (type == CTRL_ATTR_FAMILY_ID &&

	    mnl_attr_validate(attr, MNL_TYPE_U16) < 0)

		return MNL_CB_ERROR;

	tb[type] = attr;

	return MNL_CB_OK;

}

static int get_family_id_cb(const struct nlmsghdr *nlh, void *data)

{

	uint32_t *p_id = data;

	struct nlattr *tb[CTRL_ATTR_MAX + 1] = {};

	struct genlmsghdr *genl = mnl_nlmsg_get_payload(nlh);

	mnl_attr_parse(nlh, sizeof(*genl), get_family_id_attr_cb, tb);

	if (!tb[CTRL_ATTR_FAMILY_ID])

		return MNL_CB_ERROR;

	*p_id = mnl_attr_get_u16(tb[CTRL_ATTR_FAMILY_ID]);

	return MNL_CB_OK;

}

struct mnlg_socket *mnlg_socket_open(const char *family_name, uint8_t version)

{

	struct mnlg_socket *nlg;

	struct nlmsghdr *nlh;

	int one = 1;

	int err;

	nlg = malloc(sizeof(*nlg));

	if (!nlg)

		return NULL;

	nlg->buf = malloc(MNL_SOCKET_BUFFER_SIZE);

	if (!nlg->buf)

		goto err_buf_alloc;

	nlg->nl = mnl_socket_open(NETLINK_GENERIC);

	if (!nlg->nl)

		goto err_mnl_socket_open;

	/* Older kernels may no support capped/extended ACK reporting */

	mnl_socket_setsockopt(nlg->nl, NETLINK_CAP_ACK, &one, sizeof(one));

	mnl_socket_setsockopt(nlg->nl, NETLINK_EXT_ACK, &one, sizeof(one));

	err = mnl_socket_bind(nlg->nl, 0, MNL_SOCKET_AUTOPID);

	if (err < 0)

		goto err_mnl_socket_bind;

	nlg->portid = mnl_socket_get_portid(nlg->nl);

	nlh = __mnlg_msg_prepare(nlg, CTRL_CMD_GETFAMILY,

				 NLM_F_REQUEST | NLM_F_ACK, GENL_ID_CTRL, 1);

	mnl_attr_put_strz(nlh, CTRL_ATTR_FAMILY_NAME, family_name);

	err = mnlg_socket_send(nlg, nlh);

	if (err < 0)

		goto err_mnlg_socket_send;

	err = mnlg_socket_recv_run(nlg, get_family_id_cb, &nlg->id);

	if (err < 0)

		goto err_mnlg_socket_recv_run;

	nlg->version = version;

	return nlg;

err_mnlg_socket_recv_run:

err_mnlg_socket_send:

err_mnl_socket_bind:

	mnl_socket_close(nlg->nl);

err_mnl_socket_open:

	free(nlg->buf);

err_buf_alloc:

	free(nlg);

	return NULL;

}

void mnlg_socket_close(struct mnlg_socket *nlg)

{

	mnl_socket_close(nlg->nl);

	free(nlg->buf);

	free(nlg);

}