Blame devlink/mnlg.c

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/*
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 *   mnlg.c	Generic Netlink helpers for libmnl
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 *
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 *              This program is free software; you can redistribute it and/or
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 *              modify it under the terms of the GNU General Public License
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 *              as published by the Free Software Foundation; either version
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 *              2 of the License, or (at your option) any later version.
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 *
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 * Authors:     Jiri Pirko <jiri@mellanox.com>
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 */
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#include <stdlib.h>
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#include <stdbool.h>
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#include <string.h>
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#include <errno.h>
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#include <unistd.h>
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#include <time.h>
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#include <libmnl/libmnl.h>
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#include <linux/genetlink.h>
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#include "libnetlink.h"
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#include "utils.h"
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#include "mnlg.h"
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struct mnlg_socket {
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	struct mnl_socket *nl;
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	char *buf;
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	uint32_t id;
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	uint8_t version;
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	unsigned int seq;
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	unsigned int portid;
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};
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static struct nlmsghdr *__mnlg_msg_prepare(struct mnlg_socket *nlg, uint8_t cmd,
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					   uint16_t flags, uint32_t id,
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					   uint8_t version)
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{
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	struct nlmsghdr *nlh;
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	struct genlmsghdr *genl;
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	nlh = mnl_nlmsg_put_header(nlg->buf);
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	nlh->nlmsg_type	= id;
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	nlh->nlmsg_flags = flags;
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	nlg->seq = time(NULL);
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	nlh->nlmsg_seq = nlg->seq;
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	genl = mnl_nlmsg_put_extra_header(nlh, sizeof(struct genlmsghdr));
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	genl->cmd = cmd;
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	genl->version = version;
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	return nlh;
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}
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struct nlmsghdr *mnlg_msg_prepare(struct mnlg_socket *nlg, uint8_t cmd,
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				  uint16_t flags)
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{
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	return __mnlg_msg_prepare(nlg, cmd, flags, nlg->id, nlg->version);
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}
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int mnlg_socket_send(struct mnlg_socket *nlg, const struct nlmsghdr *nlh)
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{
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	return mnl_socket_sendto(nlg->nl, nlh, nlh->nlmsg_len);
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}
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static int mnlg_cb_noop(const struct nlmsghdr *nlh, void *data)
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{
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	return MNL_CB_OK;
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}
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static int mnlg_cb_error(const struct nlmsghdr *nlh, void *data)
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{
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	const struct nlmsgerr *err = mnl_nlmsg_get_payload(nlh);
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	/* Netlink subsystems returns the errno value with different signess */
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	if (err->error < 0)
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		errno = -err->error;
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	else
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		errno = err->error;
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	if (nl_dump_ext_ack(nlh, NULL))
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		return MNL_CB_ERROR;
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	return err->error == 0 ? MNL_CB_STOP : MNL_CB_ERROR;
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}
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static int mnlg_cb_stop(const struct nlmsghdr *nlh, void *data)
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{
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	int len = *(int *)NLMSG_DATA(nlh);
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	if (len < 0) {
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		errno = -len;
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		nl_dump_ext_ack_done(nlh, len);
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		return MNL_CB_ERROR;
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	}
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	return MNL_CB_STOP;
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}
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static mnl_cb_t mnlg_cb_array[NLMSG_MIN_TYPE] = {
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	[NLMSG_NOOP]	= mnlg_cb_noop,
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	[NLMSG_ERROR]	= mnlg_cb_error,
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	[NLMSG_DONE]	= mnlg_cb_stop,
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	[NLMSG_OVERRUN]	= mnlg_cb_noop,
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};
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int mnlg_socket_recv_run(struct mnlg_socket *nlg, mnl_cb_t data_cb, void *data)
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{
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	int err;
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	do {
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		err = mnl_socket_recvfrom(nlg->nl, nlg->buf,
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					  MNL_SOCKET_BUFFER_SIZE);
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		if (err <= 0)
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			break;
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		err = mnl_cb_run2(nlg->buf, err, nlg->seq, nlg->portid,
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				  data_cb, data, mnlg_cb_array,
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				  ARRAY_SIZE(mnlg_cb_array));
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	} while (err > 0);
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	return err;
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}
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struct group_info {
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	bool found;
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	uint32_t id;
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	const char *name;
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};
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static int parse_mc_grps_cb(const struct nlattr *attr, void *data)
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{
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	const struct nlattr **tb = data;
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	int type = mnl_attr_get_type(attr);
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	if (mnl_attr_type_valid(attr, CTRL_ATTR_MCAST_GRP_MAX) < 0)
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		return MNL_CB_OK;
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	switch (type) {
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	case CTRL_ATTR_MCAST_GRP_ID:
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		if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
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			return MNL_CB_ERROR;
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		break;
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	case CTRL_ATTR_MCAST_GRP_NAME:
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		if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
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			return MNL_CB_ERROR;
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		break;
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	}
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	tb[type] = attr;
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	return MNL_CB_OK;
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}
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static void parse_genl_mc_grps(struct nlattr *nested,
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			       struct group_info *group_info)
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{
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	struct nlattr *pos;
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	const char *name;
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	mnl_attr_for_each_nested(pos, nested) {
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		struct nlattr *tb[CTRL_ATTR_MCAST_GRP_MAX + 1] = {};
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		mnl_attr_parse_nested(pos, parse_mc_grps_cb, tb);
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		if (!tb[CTRL_ATTR_MCAST_GRP_NAME] ||
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		    !tb[CTRL_ATTR_MCAST_GRP_ID])
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			continue;
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		name = mnl_attr_get_str(tb[CTRL_ATTR_MCAST_GRP_NAME]);
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		if (strcmp(name, group_info->name) != 0)
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			continue;
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		group_info->id = mnl_attr_get_u32(tb[CTRL_ATTR_MCAST_GRP_ID]);
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		group_info->found = true;
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	}
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}
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static int get_group_id_attr_cb(const struct nlattr *attr, void *data)
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{
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	const struct nlattr **tb = data;
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	int type = mnl_attr_get_type(attr);
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	if (mnl_attr_type_valid(attr, CTRL_ATTR_MAX) < 0)
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		return MNL_CB_ERROR;
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	if (type == CTRL_ATTR_MCAST_GROUPS &&
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	    mnl_attr_validate(attr, MNL_TYPE_NESTED) < 0)
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		return MNL_CB_ERROR;
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	tb[type] = attr;
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	return MNL_CB_OK;
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}
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static int get_group_id_cb(const struct nlmsghdr *nlh, void *data)
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{
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	struct group_info *group_info = data;
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	struct nlattr *tb[CTRL_ATTR_MAX + 1] = {};
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	struct genlmsghdr *genl = mnl_nlmsg_get_payload(nlh);
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	mnl_attr_parse(nlh, sizeof(*genl), get_group_id_attr_cb, tb);
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	if (!tb[CTRL_ATTR_MCAST_GROUPS])
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		return MNL_CB_ERROR;
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	parse_genl_mc_grps(tb[CTRL_ATTR_MCAST_GROUPS], group_info);
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	return MNL_CB_OK;
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}
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int mnlg_socket_group_add(struct mnlg_socket *nlg, const char *group_name)
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{
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	struct nlmsghdr *nlh;
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	struct group_info group_info;
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	int err;
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	nlh = __mnlg_msg_prepare(nlg, CTRL_CMD_GETFAMILY,
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				 NLM_F_REQUEST | NLM_F_ACK, GENL_ID_CTRL, 1);
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	mnl_attr_put_u16(nlh, CTRL_ATTR_FAMILY_ID, nlg->id);
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	err = mnlg_socket_send(nlg, nlh);
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	if (err < 0)
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		return err;
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	group_info.found = false;
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	group_info.name = group_name;
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	err = mnlg_socket_recv_run(nlg, get_group_id_cb, &group_info);
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	if (err < 0)
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		return err;
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	if (!group_info.found) {
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		errno = ENOENT;
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		return -1;
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	}
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	err = mnl_socket_setsockopt(nlg->nl, NETLINK_ADD_MEMBERSHIP,
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				    &group_info.id, sizeof(group_info.id));
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	if (err < 0)
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		return err;
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	return 0;
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}
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static int get_family_id_attr_cb(const struct nlattr *attr, void *data)
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{
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	const struct nlattr **tb = data;
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	int type = mnl_attr_get_type(attr);
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	if (mnl_attr_type_valid(attr, CTRL_ATTR_MAX) < 0)
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		return MNL_CB_ERROR;
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	if (type == CTRL_ATTR_FAMILY_ID &&
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	    mnl_attr_validate(attr, MNL_TYPE_U16) < 0)
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		return MNL_CB_ERROR;
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	tb[type] = attr;
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	return MNL_CB_OK;
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}
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static int get_family_id_cb(const struct nlmsghdr *nlh, void *data)
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{
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	uint32_t *p_id = data;
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	struct nlattr *tb[CTRL_ATTR_MAX + 1] = {};
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	struct genlmsghdr *genl = mnl_nlmsg_get_payload(nlh);
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	mnl_attr_parse(nlh, sizeof(*genl), get_family_id_attr_cb, tb);
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	if (!tb[CTRL_ATTR_FAMILY_ID])
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		return MNL_CB_ERROR;
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	*p_id = mnl_attr_get_u16(tb[CTRL_ATTR_FAMILY_ID]);
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	return MNL_CB_OK;
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}
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struct mnlg_socket *mnlg_socket_open(const char *family_name, uint8_t version)
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{
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	struct mnlg_socket *nlg;
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	struct nlmsghdr *nlh;
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	int one = 1;
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	int err;
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	nlg = malloc(sizeof(*nlg));
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	if (!nlg)
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		return NULL;
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	nlg->buf = malloc(MNL_SOCKET_BUFFER_SIZE);
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	if (!nlg->buf)
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		goto err_buf_alloc;
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	nlg->nl = mnl_socket_open(NETLINK_GENERIC);
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	if (!nlg->nl)
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		goto err_mnl_socket_open;
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	/* Older kernels may no support capped/extended ACK reporting */
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	mnl_socket_setsockopt(nlg->nl, NETLINK_CAP_ACK, &one, sizeof(one));
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	mnl_socket_setsockopt(nlg->nl, NETLINK_EXT_ACK, &one, sizeof(one));
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	err = mnl_socket_bind(nlg->nl, 0, MNL_SOCKET_AUTOPID);
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	if (err < 0)
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		goto err_mnl_socket_bind;
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	nlg->portid = mnl_socket_get_portid(nlg->nl);
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	nlh = __mnlg_msg_prepare(nlg, CTRL_CMD_GETFAMILY,
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				 NLM_F_REQUEST | NLM_F_ACK, GENL_ID_CTRL, 1);
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	mnl_attr_put_strz(nlh, CTRL_ATTR_FAMILY_NAME, family_name);
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	err = mnlg_socket_send(nlg, nlh);
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	if (err < 0)
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		goto err_mnlg_socket_send;
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	err = mnlg_socket_recv_run(nlg, get_family_id_cb, &nlg->id);
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	if (err < 0)
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		goto err_mnlg_socket_recv_run;
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	nlg->version = version;
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	return nlg;
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err_mnlg_socket_recv_run:
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err_mnlg_socket_send:
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err_mnl_socket_bind:
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	mnl_socket_close(nlg->nl);
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err_mnl_socket_open:
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	free(nlg->buf);
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err_buf_alloc:
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	free(nlg);
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	return NULL;
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}
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void mnlg_socket_close(struct mnlg_socket *nlg)
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{
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	mnl_socket_close(nlg->nl);
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	free(nlg->buf);
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	free(nlg);
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}
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int mnlg_socket_get_fd(struct mnlg_socket *nlg)
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{
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	return mnl_socket_get_fd(nlg->nl);
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}