1 /*
2 * Copyright 2012 Daniel Drown <dan-android@drown.org>
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 *
16 * setif.c - network interface configuration
17 */
18 #include <errno.h>
19 #include <net/if.h>
20 #include <netinet/in.h>
21
22 #include <linux/rtnetlink.h>
23 #include <netlink/handlers.h>
24 #include <netlink/msg.h>
25
26 #include "logging.h"
27 #include "netlink_msg.h"
28
29 #define DEBUG_OPTNAME(a) \
30 case (a): { \
31 optname = #a; \
32 break; \
33 }
34
35 /* function: add_address
36 * adds an IP address to/from an interface, returns 0 on success and <0 on failure
37 * ifname - name of interface to change
38 * family - address family (AF_INET, AF_INET6)
39 * address - pointer to a struct in_addr or in6_addr
40 * prefixlen - bitlength of network (example: 24 for AF_INET's 255.255.255.0)
41 * broadcast - broadcast address (only for AF_INET, ignored for AF_INET6)
42 */
add_address(const char * ifname,int family,const void * address,int prefixlen,const void * broadcast)43 int add_address(const char *ifname, int family, const void *address, int prefixlen,
44 const void *broadcast) {
45 int retval;
46 size_t addr_size;
47 struct ifaddrmsg ifa;
48 struct nl_msg *msg = NULL;
49
50 addr_size = inet_family_size(family);
51 if (addr_size == 0) {
52 retval = -EAFNOSUPPORT;
53 goto cleanup;
54 }
55
56 memset(&ifa, 0, sizeof(ifa));
57 if (!(ifa.ifa_index = if_nametoindex(ifname))) {
58 retval = -ENODEV;
59 goto cleanup;
60 }
61 ifa.ifa_family = family;
62 ifa.ifa_prefixlen = prefixlen;
63 ifa.ifa_scope = RT_SCOPE_UNIVERSE;
64
65 msg =
66 nlmsg_alloc_ifaddr(RTM_NEWADDR, NLM_F_ACK | NLM_F_REQUEST | NLM_F_CREATE | NLM_F_REPLACE, &ifa);
67 if (!msg) {
68 retval = -ENOMEM;
69 goto cleanup;
70 }
71
72 if (nla_put(msg, IFA_LOCAL, addr_size, address) < 0) {
73 retval = -ENOMEM;
74 goto cleanup;
75 }
76 if (family == AF_INET6) {
77 // AF_INET6 gets IFA_LOCAL + IFA_ADDRESS
78 if (nla_put(msg, IFA_ADDRESS, addr_size, address) < 0) {
79 retval = -ENOMEM;
80 goto cleanup;
81 }
82 } else if (family == AF_INET) {
83 // AF_INET gets IFA_LOCAL + IFA_BROADCAST
84 if (nla_put(msg, IFA_BROADCAST, addr_size, broadcast) < 0) {
85 retval = -ENOMEM;
86 goto cleanup;
87 }
88 } else {
89 retval = -EAFNOSUPPORT;
90 goto cleanup;
91 }
92
93 retval = netlink_sendrecv(msg);
94
95 cleanup:
96 if (msg) nlmsg_free(msg);
97
98 return retval;
99 }
100
101 /* function: if_up
102 * sets interface link state to up and sets mtu, returns 0 on success and <0 on failure
103 * ifname - interface name to change
104 * mtu - new mtu
105 */
if_up(const char * ifname,int mtu)106 int if_up(const char *ifname, int mtu) {
107 int retval = -1;
108 struct ifinfomsg ifi;
109 struct nl_msg *msg = NULL;
110
111 memset(&ifi, 0, sizeof(ifi));
112 if (!(ifi.ifi_index = if_nametoindex(ifname))) {
113 retval = -ENODEV;
114 goto cleanup;
115 }
116 ifi.ifi_change = IFF_UP;
117 ifi.ifi_flags = IFF_UP;
118
119 msg = nlmsg_alloc_ifinfo(RTM_SETLINK, NLM_F_ACK | NLM_F_REQUEST | NLM_F_ROOT, &ifi);
120 if (!msg) {
121 retval = -ENOMEM;
122 goto cleanup;
123 }
124
125 if (nla_put(msg, IFLA_MTU, 4, &mtu) < 0) {
126 retval = -ENOMEM;
127 goto cleanup;
128 }
129
130 retval = netlink_sendrecv(msg);
131
132 cleanup:
133 if (msg) nlmsg_free(msg);
134
135 return retval;
136 }
137
do_anycast_setsockopt(int sock,int what,struct in6_addr * addr,int ifindex)138 static int do_anycast_setsockopt(int sock, int what, struct in6_addr *addr, int ifindex) {
139 struct ipv6_mreq mreq = { *addr, ifindex };
140 char *optname;
141 int ret;
142
143 switch (what) {
144 DEBUG_OPTNAME(IPV6_JOIN_ANYCAST)
145 DEBUG_OPTNAME(IPV6_LEAVE_ANYCAST)
146 default:
147 optname = "???";
148 break;
149 }
150
151 ret = setsockopt(sock, SOL_IPV6, what, &mreq, sizeof(mreq));
152 if (ret) {
153 logmsg(ANDROID_LOG_ERROR, "%s: setsockopt(%s): %s", __func__, optname, strerror(errno));
154 }
155
156 return ret;
157 }
158
159 /* function: add_anycast_address
160 * adds an anycast IPv6 address to an interface, returns 0 on success and <0 on failure
161 * sock - the socket to add the address to
162 * addr - the IP address to add
163 * ifname - name of interface to add the address to
164 */
add_anycast_address(int sock,struct in6_addr * addr,const char * ifname)165 int add_anycast_address(int sock, struct in6_addr *addr, const char *ifname) {
166 int ifindex;
167
168 ifindex = if_nametoindex(ifname);
169 if (!ifindex) {
170 logmsg(ANDROID_LOG_ERROR, "%s: unknown ifindex for interface %s", __func__, ifname);
171 return -ENODEV;
172 }
173
174 return do_anycast_setsockopt(sock, IPV6_JOIN_ANYCAST, addr, ifindex);
175 }
176
177 /* function: del_anycast_address
178 * removes an anycast IPv6 address from the system, returns 0 on success and <0 on failure
179 * sock - the socket to remove from, must have had the address added via add_anycast_address
180 * addr - the IP address to remove
181 */
del_anycast_address(int sock,struct in6_addr * addr)182 int del_anycast_address(int sock, struct in6_addr *addr) {
183 return do_anycast_setsockopt(sock, IPV6_LEAVE_ANYCAST, addr, 0);
184 }
185