1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
2 /***
3 Copyright © 2014 Intel Corporation. All rights reserved.
4 ***/
5
6 #include <errno.h>
7 #include <netinet/icmp6.h>
8 #include <netinet/in.h>
9 #include <netinet/ip6.h>
10 #include <stdio.h>
11 #include <string.h>
12 #include <sys/types.h>
13 #include <unistd.h>
14 #include <net/if.h>
15 #include <linux/if_packet.h>
16
17 #include "fd-util.h"
18 #include "icmp6-util.h"
19 #include "in-addr-util.h"
20 #include "io-util.h"
21 #include "socket-util.h"
22
23 #define IN6ADDR_ALL_ROUTERS_MULTICAST_INIT \
24 { { { 0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
25 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02 } } }
26
27 #define IN6ADDR_ALL_NODES_MULTICAST_INIT \
28 { { { 0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
29 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 } } }
30
icmp6_bind_router_message(const struct icmp6_filter * filter,const struct ipv6_mreq * mreq)31 static int icmp6_bind_router_message(const struct icmp6_filter *filter,
32 const struct ipv6_mreq *mreq) {
33 int ifindex = mreq->ipv6mr_interface;
34 _cleanup_close_ int s = -1;
35 int r;
36
37 assert(filter);
38 assert(mreq);
39
40 s = socket(AF_INET6, SOCK_RAW | SOCK_CLOEXEC | SOCK_NONBLOCK, IPPROTO_ICMPV6);
41 if (s < 0)
42 return -errno;
43
44 if (setsockopt(s, IPPROTO_ICMPV6, ICMP6_FILTER, filter, sizeof(*filter)) < 0)
45 return -errno;
46
47 if (setsockopt(s, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, mreq, sizeof(*mreq)) < 0)
48 return -errno;
49
50 /* RFC 3315, section 6.7, bullet point 2 may indicate that an
51 IPV6_PKTINFO socket option also applies for ICMPv6 multicast.
52 Empirical experiments indicates otherwise and therefore an
53 IPV6_MULTICAST_IF socket option is used here instead */
54 r = setsockopt_int(s, IPPROTO_IPV6, IPV6_MULTICAST_IF, ifindex);
55 if (r < 0)
56 return r;
57
58 r = setsockopt_int(s, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, false);
59 if (r < 0)
60 return r;
61
62 r = setsockopt_int(s, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, 255);
63 if (r < 0)
64 return r;
65
66 r = setsockopt_int(s, IPPROTO_IPV6, IPV6_UNICAST_HOPS, 255);
67 if (r < 0)
68 return r;
69
70 r = setsockopt_int(s, SOL_IPV6, IPV6_RECVHOPLIMIT, true);
71 if (r < 0)
72 return r;
73
74 r = setsockopt_int(s, SOL_SOCKET, SO_TIMESTAMP, true);
75 if (r < 0)
76 return r;
77
78 r = socket_bind_to_ifindex(s, ifindex);
79 if (r < 0)
80 return r;
81
82 return TAKE_FD(s);
83 }
84
icmp6_bind_router_solicitation(int ifindex)85 int icmp6_bind_router_solicitation(int ifindex) {
86 struct icmp6_filter filter = {};
87 struct ipv6_mreq mreq = {
88 .ipv6mr_multiaddr = IN6ADDR_ALL_NODES_MULTICAST_INIT,
89 .ipv6mr_interface = ifindex,
90 };
91
92 ICMP6_FILTER_SETBLOCKALL(&filter);
93 ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT, &filter);
94
95 return icmp6_bind_router_message(&filter, &mreq);
96 }
97
icmp6_bind_router_advertisement(int ifindex)98 int icmp6_bind_router_advertisement(int ifindex) {
99 struct icmp6_filter filter = {};
100 struct ipv6_mreq mreq = {
101 .ipv6mr_multiaddr = IN6ADDR_ALL_ROUTERS_MULTICAST_INIT,
102 .ipv6mr_interface = ifindex,
103 };
104
105 ICMP6_FILTER_SETBLOCKALL(&filter);
106 ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT, &filter);
107
108 return icmp6_bind_router_message(&filter, &mreq);
109 }
110
icmp6_send_router_solicitation(int s,const struct ether_addr * ether_addr)111 int icmp6_send_router_solicitation(int s, const struct ether_addr *ether_addr) {
112 struct sockaddr_in6 dst = {
113 .sin6_family = AF_INET6,
114 .sin6_addr = IN6ADDR_ALL_ROUTERS_MULTICAST_INIT,
115 };
116 struct {
117 struct nd_router_solicit rs;
118 struct nd_opt_hdr rs_opt;
119 struct ether_addr rs_opt_mac;
120 } _packed_ rs = {
121 .rs.nd_rs_type = ND_ROUTER_SOLICIT,
122 .rs_opt.nd_opt_type = ND_OPT_SOURCE_LINKADDR,
123 .rs_opt.nd_opt_len = 1,
124 };
125 struct iovec iov = {
126 .iov_base = &rs,
127 .iov_len = sizeof(rs),
128 };
129 struct msghdr msg = {
130 .msg_name = &dst,
131 .msg_namelen = sizeof(dst),
132 .msg_iov = &iov,
133 .msg_iovlen = 1,
134 };
135
136 assert(s >= 0);
137 assert(ether_addr);
138
139 rs.rs_opt_mac = *ether_addr;
140
141 if (sendmsg(s, &msg, 0) < 0)
142 return -errno;
143
144 return 0;
145 }
146
icmp6_receive(int fd,void * buffer,size_t size,struct in6_addr * ret_dst,triple_timestamp * ret_timestamp)147 int icmp6_receive(int fd, void *buffer, size_t size, struct in6_addr *ret_dst,
148 triple_timestamp *ret_timestamp) {
149
150 /* This needs to be initialized with zero. See #20741. */
151 CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(int)) + /* ttl */
152 CMSG_SPACE_TIMEVAL) control = {};
153 struct iovec iov = {};
154 union sockaddr_union sa = {};
155 struct msghdr msg = {
156 .msg_name = &sa.sa,
157 .msg_namelen = sizeof(sa),
158 .msg_iov = &iov,
159 .msg_iovlen = 1,
160 .msg_control = &control,
161 .msg_controllen = sizeof(control),
162 };
163 struct cmsghdr *cmsg;
164 struct in6_addr addr = {};
165 triple_timestamp t = {};
166 ssize_t len;
167
168 iov = IOVEC_MAKE(buffer, size);
169
170 len = recvmsg_safe(fd, &msg, MSG_DONTWAIT);
171 if (len < 0)
172 return (int) len;
173
174 if ((size_t) len != size)
175 return -EINVAL;
176
177 if (msg.msg_namelen == sizeof(struct sockaddr_in6) &&
178 sa.in6.sin6_family == AF_INET6) {
179
180 addr = sa.in6.sin6_addr;
181 if (!in6_addr_is_link_local(&addr))
182 return -EADDRNOTAVAIL;
183
184 } else if (msg.msg_namelen > 0)
185 return -EPFNOSUPPORT;
186
187 /* namelen == 0 only happens when running the test-suite over a socketpair */
188
189 assert(!(msg.msg_flags & MSG_TRUNC));
190
191 CMSG_FOREACH(cmsg, &msg) {
192 if (cmsg->cmsg_level == SOL_IPV6 &&
193 cmsg->cmsg_type == IPV6_HOPLIMIT &&
194 cmsg->cmsg_len == CMSG_LEN(sizeof(int))) {
195 int hops = *(int*) CMSG_DATA(cmsg);
196
197 if (hops != 255)
198 return -EMULTIHOP;
199 }
200
201 if (cmsg->cmsg_level == SOL_SOCKET &&
202 cmsg->cmsg_type == SO_TIMESTAMP &&
203 cmsg->cmsg_len == CMSG_LEN(sizeof(struct timeval)))
204 triple_timestamp_from_realtime(&t, timeval_load((struct timeval*) CMSG_DATA(cmsg)));
205 }
206
207 if (!triple_timestamp_is_set(&t))
208 triple_timestamp_get(&t);
209
210 *ret_dst = addr;
211 *ret_timestamp = t;
212 return 0;
213 }
214