nf-queue.c

/* SPDX-License-Identifier: LGPL-2.1-only */
/*
 * Copyright (c) 2007, 2008 Patrick McHardy <kaber@trash.net>
 * Copyright (c) 2010  Karl Hiramoto <karl@hiramoto.org>
 */
 
#include <netlink/cli/utils.h>
#include <netlink/cli/link.h>
#include <netinet/in.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nfnetlink_queue.h>
#include <netlink/netfilter/nfnl.h>
#include <netlink/netfilter/queue.h>
#include <netlink/netfilter/queue_msg.h>
 
#include <linux/netlink.h>
 
static struct nl_sock *nf_sock;
 
static struct nfnl_queue *alloc_queue(void)
{
        struct nfnl_queue *queue;
 
        queue = nfnl_queue_alloc();
        if (!queue)
                nl_cli_fatal(ENOMEM, "Unable to allocate queue object");
 
        return queue;
}
 
 
static void obj_input(struct nl_object *obj, void *arg)
{
        struct nfnl_queue_msg *msg = (struct nfnl_queue_msg *) obj;
        struct nl_dump_params dp = {
                .dp_type = NL_DUMP_STATS,
                .dp_fd = stdout,
                .dp_dump_msgtype = 1,
        };
 
        nfnl_queue_msg_set_verdict(msg, NF_ACCEPT);
        nl_object_dump(obj, &dp);
        nfnl_queue_msg_send_verdict(nf_sock, msg);
}
 
static int event_input(struct nl_msg *msg, void *arg)
{
        if (nl_msg_parse(msg, &obj_input, NULL) < 0)
                fprintf(stderr, "<<EVENT>> Unknown message type\n");
 
        /* Exit nl_recvmsgs_def() and return to the main select() */
        return NL_STOP;
}
 
int main(int argc, char *argv[])
{
        struct nl_sock *rt_sock;
        struct nfnl_queue *queue;
        int copy_mode;
        uint32_t copy_range;
        int err = 1;
        int family;
 
        nf_sock = nfnl_queue_socket_alloc();
        if (nf_sock == NULL)
                nl_cli_fatal(ENOBUFS, "Unable to allocate netlink socket");
 
        nl_socket_disable_seq_check(nf_sock);
        nl_socket_modify_cb(nf_sock, NL_CB_VALID, NL_CB_CUSTOM, event_input, NULL);
 
        if ((argc > 1 && !strcasecmp(argv[1], "-h")) || argc < 3) {
                printf("Usage: nf-queue family group [ copy_mode ] "
                       "[ copy_range ]\n");
                printf("family: [ inet | inet6 | ... ] \n");
                printf("group: the --queue-num arg that you gave to iptables\n");
                printf("copy_mode: [ none | meta | packet ] \n");
                return 2;
        }
 
        nl_cli_connect(nf_sock, NETLINK_NETFILTER);
 
        if ((family = nl_str2af(argv[1])) == AF_UNSPEC)
                nl_cli_fatal(NLE_INVAL, "Unknown family \"%s\"", argv[1]);
 
        nfnl_queue_pf_unbind(nf_sock, family);
        if ((err = nfnl_queue_pf_bind(nf_sock, family)) < 0)
                nl_cli_fatal(err, "Unable to bind logger: %s",
                             nl_geterror(err));
 
        queue = alloc_queue();
        nfnl_queue_set_group(queue, atoi(argv[2]));
 
        copy_mode = NFNL_QUEUE_COPY_PACKET;
        if (argc > 3) {
                copy_mode = nfnl_queue_str2copy_mode(argv[3]);
                if (copy_mode < 0)
                        nl_cli_fatal(copy_mode,
                                     "Unable to parse copy mode \"%s\": %s",
                                     argv[3], nl_geterror(copy_mode));
        }
        nfnl_queue_set_copy_mode(queue, copy_mode);
 
        copy_range = 0xFFFF;
        if (argc > 4)
                copy_range = atoi(argv[4]);
        nfnl_queue_set_copy_range(queue, copy_range);
 
        if ((err = nfnl_queue_create(nf_sock, queue)) < 0)
                nl_cli_fatal(err, "Unable to bind queue: %s", nl_geterror(err));
 
        rt_sock = nl_cli_alloc_socket();
        nl_cli_connect(rt_sock, NETLINK_ROUTE);
        nl_cli_link_alloc_cache(rt_sock);
 
        nl_socket_set_buffer_size(nf_sock, 1024*127, 1024*127);
 
        while (1) {
                fd_set rfds;
                int nffd, rtfd, maxfd, retval;
 
                FD_ZERO(&rfds);
 
                maxfd = nffd = nl_socket_get_fd(nf_sock);
                FD_SET(nffd, &rfds);
 
                rtfd = nl_socket_get_fd(rt_sock);
                FD_SET(rtfd, &rfds);
                if (maxfd < rtfd)
                        maxfd = rtfd;
 
                /* wait for an incoming message on the netlink socket */
                retval = select(maxfd+1, &rfds, NULL, NULL, NULL);
 
                if (retval) {
                        if (FD_ISSET(nffd, &rfds))
                                nl_recvmsgs_default(nf_sock);
                        if (FD_ISSET(rtfd, &rfds))
                                nl_recvmsgs_default(rt_sock);
                }
        }
 
        return 0;
}