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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2022 Felix Fietkau <nbd@nbd.name>
*/
#define _GNU_SOURCE
#include <sys/types.h>
#include <sys/socket.h>
#include <netlink/msg.h>
#include <netlink/attr.h>
#include <netlink/socket.h>
#include <linux/rtnetlink.h>
#include "unetd.h"
static struct nl_sock *rtnl;
bool rtnl_ignore_errors;
static int
unetd_nl_error_cb(struct sockaddr_nl *nla, struct nlmsgerr *err,
void *arg)
{
struct nlmsghdr *nlh = (struct nlmsghdr *) err - 1;
struct nlattr *tb[NLMSGERR_ATTR_MAX + 1];
struct nlattr *attrs;
int ack_len = sizeof(*nlh) + sizeof(int) + sizeof(*nlh);
int len = nlh->nlmsg_len;
const char *errstr = "(unknown)";
if (rtnl_ignore_errors)
return NL_STOP;
if (!(nlh->nlmsg_flags & NLM_F_ACK_TLVS))
return NL_STOP;
if (!(nlh->nlmsg_flags & NLM_F_CAPPED))
ack_len += err->msg.nlmsg_len - sizeof(*nlh);
attrs = (void *) ((unsigned char *) nlh + ack_len);
len -= ack_len;
nla_parse(tb, NLMSGERR_ATTR_MAX, attrs, len, NULL);
if (tb[NLMSGERR_ATTR_MSG])
errstr = nla_data(tb[NLMSGERR_ATTR_MSG]);
D("Netlink error(%d): %s\n", err->error, errstr);
return NL_STOP;
}
int rtnl_call(struct nl_msg *msg)
{
int ret;
ret = nl_send_auto_complete(rtnl, msg);
nlmsg_free(msg);
if (ret < 0)
return ret;
return nl_wait_for_ack(rtnl);
}
int rtnl_init(void)
{
int fd, opt;
if (rtnl)
return 0;
rtnl = nl_socket_alloc();
if (!rtnl)
return -1;
if (nl_connect(rtnl, NETLINK_ROUTE))
goto free;
nl_socket_disable_seq_check(rtnl);
nl_socket_set_buffer_size(rtnl, 65536, 0);
nl_cb_err(nl_socket_get_cb(rtnl), NL_CB_CUSTOM, unetd_nl_error_cb, NULL);
fd = nl_socket_get_fd(rtnl);
opt = 1;
setsockopt(fd, SOL_NETLINK, NETLINK_EXT_ACK, &opt, sizeof(opt));
opt = 1;
setsockopt(fd, SOL_NETLINK, NETLINK_CAP_ACK, &opt, sizeof(opt));
return 0;
free:
nl_socket_free(rtnl);
rtnl = NULL;
return -1;
}
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