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/* SPDX-License-Identifier: LGPL-2.1-only */
/*
* Copyright (c) 2018 Avast software
*/
#include <netlink/cli/utils.h>
#include <netlink/cli/ct.h>
#include <linux/netlink.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_conntrack.h>
struct private_nl_object
{
int ce_refcnt;
struct nl_object_ops * ce_ops;
struct nl_cache * ce_cache;
struct nl_list_head ce_list;
int ce_msgtype;
int ce_flags;
uint64_t ce_mask;
};
static void nf_conntrack_parse_callback(struct nl_object *obj, void *opaque)
{
struct nl_dump_params params = {
.dp_fd = stdout,
.dp_type = NL_DUMP_DETAILS,
};
nl_object_dump(obj, ¶ms);
}
static int nf_conntrack_event_callback(struct nl_msg *msg, void *opaque)
{
int err;
struct nlmsghdr *hdr = nlmsg_hdr(msg);
enum cntl_msg_types type = (enum cntl_msg_types) NFNL_MSG_TYPE(hdr->nlmsg_type);
int flags = hdr->nlmsg_flags;
if (type == IPCTNL_MSG_CT_DELETE) {
printf("DELETE ");
} else if (type == IPCTNL_MSG_CT_NEW) {
if (flags & (NLM_F_CREATE|NLM_F_EXCL)) {
printf("NEW ");
} else {
printf("UPDATE ");
}
} else {
printf("UNKNOWN ");
}
if ((err = nl_msg_parse(msg, &nf_conntrack_parse_callback, opaque)) < 0) {
nl_cli_fatal(err, "nl_msg_parse: %s", nl_geterror(err));
}
/* Continue with next event */
return NL_OK;
}
int main(int argc, char *argv[])
{
struct nl_sock *socket;
int err;
socket = nl_cli_alloc_socket();
if (socket == NULL) {
nl_cli_fatal(ENOBUFS, "Unable to allocate netlink socket");
}
/*
* Disable sequence number checking.
* This is required to allow messages to be processed which were not requested by
* a preceding request message, e.g. netlink events.
*/
nl_socket_disable_seq_check(socket);
/* subscribe conntrack events */
nl_join_groups(socket, NF_NETLINK_CONNTRACK_NEW |
NF_NETLINK_CONNTRACK_UPDATE |
NF_NETLINK_CONNTRACK_DESTROY |
NF_NETLINK_CONNTRACK_EXP_NEW |
NF_NETLINK_CONNTRACK_EXP_UPDATE |
NF_NETLINK_CONNTRACK_EXP_DESTROY);
nl_cli_connect(socket, NETLINK_NETFILTER);
nl_socket_modify_cb(socket, NL_CB_VALID, NL_CB_CUSTOM, &nf_conntrack_event_callback, 0);
while (1) {
errno = 0;
if ((err = nl_recvmsgs_default(socket)) < 0) {
switch (errno) {
case ENOBUFS:
// just print warning
fprintf(stderr, "Lost events because of ENOBUFS\n");
break;
case EAGAIN:
case EINTR:
// continue reading
break;
default:
nl_cli_fatal(err, "Failed to receive: %s", nl_geterror(err));
}
}
}
}
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