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b45ac5f5c6
config.h (or, transitively, zebra.h) must be the first include file listed for autoconf things like _GNU_SOURCE and _POSIX_C_SOURCE to work correctly. Signed-off-by: David Lamparter <equinox@diac24.net>
103 lines
2.5 KiB
C
103 lines
2.5 KiB
C
/*
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* Multicast Traceroute for FRRouting
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* Copyright (C) 2018 Mladen Sablic
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; see the file COPYING; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#ifdef __linux__
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#include <asm/types.h>
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#include <linux/netlink.h>
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#include <linux/rtnetlink.h>
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#include <sys/types.h>
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#include <stdio.h>
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#include <arpa/inet.h>
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#include <string.h>
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#include "mtracebis_netlink.h"
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#include "mtracebis_routeget.h"
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static int find_dst(struct nlmsghdr *n, struct in_addr *src, struct in_addr *gw)
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{
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struct rtmsg *r = NLMSG_DATA(n);
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int len = n->nlmsg_len;
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struct rtattr *tb[RTA_MAX + 1];
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len -= NLMSG_LENGTH(sizeof(*r));
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if (len < 0) {
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fprintf(stderr, "BUG: wrong nlmsg len %d\n", len);
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return -1;
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}
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parse_rtattr(tb, RTA_MAX, RTM_RTA(r), len);
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if (tb[RTA_PREFSRC])
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src->s_addr = *(uint32_t *)RTA_DATA(tb[RTA_PREFSRC]);
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if (tb[RTA_GATEWAY])
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gw->s_addr = *(uint32_t *)RTA_DATA(tb[RTA_GATEWAY]);
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if (tb[RTA_OIF])
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return *(int *)RTA_DATA(tb[RTA_OIF]);
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return 0;
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}
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int routeget(struct in_addr dst, struct in_addr *src, struct in_addr *gw)
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{
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struct {
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struct nlmsghdr n;
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struct rtmsg r;
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char buf[1024];
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} req;
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int ret;
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struct rtnl_handle rth = {.fd = -1};
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memset(&req, 0, sizeof(req));
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req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
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req.n.nlmsg_flags = NLM_F_REQUEST;
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req.n.nlmsg_type = RTM_GETROUTE;
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req.r.rtm_family = AF_INET;
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req.r.rtm_table = 0;
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req.r.rtm_protocol = 0;
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req.r.rtm_scope = 0;
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req.r.rtm_type = 0;
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req.r.rtm_src_len = 0;
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req.r.rtm_dst_len = 0;
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req.r.rtm_tos = 0;
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addattr_l(&req.n, sizeof(req), RTA_DST, &dst.s_addr, 4);
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req.r.rtm_dst_len = 32;
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ret = rtnl_open(&rth, 0);
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if (ret < 0 || rth.fd <= 0)
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return ret;
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if (rtnl_talk(&rth, &req.n, 0, 0, &req.n, NULL, NULL) < 0) {
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ret = -1;
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goto close_rth;
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}
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ret = find_dst(&req.n, src, gw);
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close_rth:
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rtnl_close(&rth);
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return ret;
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}
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#endif /* __linux__ */
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