1/*	$OpenBSD: reply.c,v 1.5 2016/09/02 16:46:29 renato Exp $ */
2
3/*
4 * Copyright (c) 2015 Renato Westphal <renato@openbsd.org>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19#include <sys/types.h>
20#include <netinet/in.h>
21#include <netinet/ip.h>
22#include <netinet/ip6.h>
23
24#include <stdlib.h>
25
26#include "eigrpd.h"
27#include "eigrpe.h"
28#include "log.h"
29
30/* reply packet handling */
31
32void
33send_reply(struct nbr *nbr, struct rinfo_head *rinfo_list, int siareply)
34{
35	struct eigrp		*eigrp = nbr->ei->eigrp;
36	struct ibuf		*buf;
37	uint16_t		 opcode;
38	struct rinfo_entry	*re;
39	int			 size;
40	int			 route_len;
41
42	if (rinfo_list == NULL || TAILQ_EMPTY(rinfo_list))
43		return;
44
45	do {
46		if ((buf = ibuf_dynamic(PKG_DEF_SIZE,
47		    IP_MAXPACKET - sizeof(struct ip))) == NULL)
48			fatal("send_reply");
49
50		if (!siareply)
51			 opcode = EIGRP_OPC_REPLY;
52		else
53			 opcode = EIGRP_OPC_SIAREPLY;
54
55		/* EIGRP header */
56		if (gen_eigrp_hdr(buf, opcode, 0, eigrp->seq_num, eigrp->as))
57			goto fail;
58
59		switch (eigrp->af) {
60		case AF_INET:
61			size = sizeof(struct ip);
62			break;
63		case AF_INET6:
64			size = sizeof(struct ip6_hdr);
65			break;
66		default:
67			fatalx("send_reply: unknown af");
68		}
69		size += sizeof(struct eigrp_hdr);
70
71		while ((re = TAILQ_FIRST(rinfo_list)) != NULL) {
72			route_len = len_route_tlv(&re->rinfo);
73			/* don't exceed the MTU to avoid IP fragmentation */
74			if (size + route_len > nbr->ei->iface->mtu) {
75				rtp_send_ucast(nbr, buf);
76				break;
77			}
78			size += route_len;
79
80			if (gen_route_tlv(buf, &re->rinfo))
81				goto fail;
82			TAILQ_REMOVE(rinfo_list, re, entry);
83			free(re);
84		}
85	} while (!TAILQ_EMPTY(rinfo_list));
86
87	/* reply packets are always unicast */
88	rtp_send_ucast(nbr, buf);
89	return;
90fail:
91	log_warnx("%s: failed to send message", __func__);
92	if (rinfo_list)
93		message_list_clr(rinfo_list);
94	ibuf_free(buf);
95	return;
96}
97
98void
99recv_reply(struct nbr *nbr, struct rinfo_head *rinfo_list, int siareply)
100{
101	int			 type;
102	struct rinfo_entry	*re;
103
104	/*
105	 * draft-savage-eigrp-02 - Section 4.3:
106	 * "When a REPLY packet is received, there is no reason to process
107	 * the packet before an acknowledgment is sent. Therefore, an Ack
108	 * packet is sent immediately and then the packet is processed."
109	 */
110	rtp_send_ack(nbr);
111
112	if (!siareply)
113		type = IMSG_RECV_REPLY;
114	else
115		type = IMSG_RECV_SIAREPLY;
116
117	TAILQ_FOREACH(re, rinfo_list, entry)
118		eigrpe_imsg_compose_rde(type, nbr->peerid, 0, &re->rinfo,
119		    sizeof(re->rinfo));
120}
121