1 /* $OpenBSD: hello.c,v 1.6 2022/12/28 21:30:16 jmc 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
23 #include <arpa/inet.h>
24 #include <string.h>
25
26 #include "eigrpd.h"
27 #include "eigrpe.h"
28 #include "log.h"
29
30 /* hello packet handling */
31
32 void
send_hello(struct eigrp_iface * ei,struct seq_addr_head * seq_addr_list,uint32_t mcast_seq)33 send_hello(struct eigrp_iface *ei, struct seq_addr_head *seq_addr_list,
34 uint32_t mcast_seq)
35 {
36 struct eigrp *eigrp = ei->eigrp;
37 struct ibuf *buf;
38 uint8_t flags = 0;
39
40 if ((buf = ibuf_dynamic(PKG_DEF_SIZE,
41 IP_MAXPACKET - sizeof(struct ip))) == NULL)
42 fatal("send_hello");
43
44 /* EIGRP header */
45 if (gen_eigrp_hdr(buf, EIGRP_OPC_HELLO, flags, 0, eigrp->as))
46 goto fail;
47
48 if (gen_parameter_tlv(buf, ei, 0))
49 goto fail;
50
51 if (gen_sw_version_tlv(buf))
52 goto fail;
53
54 if (seq_addr_list && !TAILQ_EMPTY(seq_addr_list) &&
55 gen_sequence_tlv(buf, seq_addr_list))
56 goto fail;
57
58 if (mcast_seq && gen_mcast_seq_tlv(buf, mcast_seq))
59 goto fail;
60
61 /* send unreliably */
62 send_packet(ei, NULL, 0, buf);
63 ibuf_free(buf);
64 return;
65 fail:
66 log_warnx("%s: failed to send message", __func__);
67 ibuf_free(buf);
68 }
69
70 void
send_peerterm(struct nbr * nbr)71 send_peerterm(struct nbr *nbr)
72 {
73 struct eigrp *eigrp = nbr->ei->eigrp;
74 struct ibuf *buf;
75 uint8_t flags = 0;
76
77 if ((buf = ibuf_dynamic(PKG_DEF_SIZE,
78 IP_MAXPACKET - sizeof(struct ip))) == NULL)
79 fatal("send_hello");
80
81 /* EIGRP header */
82 if (gen_eigrp_hdr(buf, EIGRP_OPC_HELLO, flags, 0, eigrp->as))
83 goto fail;
84
85 if (gen_parameter_tlv(buf, nbr->ei, 1))
86 goto fail;
87
88 /* send unreliably */
89 send_packet(nbr->ei, nbr, 0, buf);
90 ibuf_free(buf);
91 return;
92 fail:
93 log_warnx("%s: failed to send message", __func__);
94 ibuf_free(buf);
95 }
96
97
98 void
recv_hello(struct eigrp_iface * ei,union eigrpd_addr * src,struct nbr * nbr,struct tlv_parameter * tp)99 recv_hello(struct eigrp_iface *ei, union eigrpd_addr *src, struct nbr *nbr,
100 struct tlv_parameter *tp)
101 {
102 /*
103 * Some old Cisco routers seems to use the "parameters tlv" with all
104 * K-values set to 255 (except k6) to inform that the neighbor has been
105 * reset. The "peer termination" tlv described in the draft for the same
106 * purpose is probably something introduced recently. Let's check for
107 * this case to maintain backward compatibility.
108 */
109 if (tp->kvalues[0] == 255 && tp->kvalues[1] == 255 &&
110 tp->kvalues[2] == 255 && tp->kvalues[3] == 255 &&
111 tp->kvalues[4] == 255 && tp->kvalues[5] == 0) {
112 if (nbr) {
113 log_debug("%s: peer termination", __func__);
114 nbr_del(nbr);
115 }
116 return;
117 }
118
119 if (nbr == NULL) {
120 if (memcmp(ei->eigrp->kvalues, tp->kvalues, 6) != 0) {
121 log_debug("%s: k-values don't match (nbr %s)",
122 __func__, log_addr(ei->eigrp->af, src));
123 return;
124 }
125
126 nbr = nbr_new(ei, src, ntohs(tp->holdtime), 0);
127
128 /* send an expedited hello */
129 send_hello(ei, NULL, 0);
130
131 send_update(nbr->ei, nbr, EIGRP_HDR_FLAG_INIT, NULL);
132 }
133 }
134