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 <netinet/in.h>
20 #include <net/if.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) case (a): { optname = #a; break; }
30
31 /* function: add_address
32 * adds an IP address to/from an interface, returns 0 on success and <0 on failure
33 * ifname - name of interface to change
34 * family - address family (AF_INET, AF_INET6)
35 * address - pointer to a struct in_addr or in6_addr
36 * prefixlen - bitlength of network (example: 24 for AF_INET's 255.255.255.0)
37 * broadcast - broadcast address (only for AF_INET, ignored for AF_INET6)
38 */
add_address(const char * ifname,int family,const void * address,int prefixlen,const void * broadcast)39 int add_address(const char *ifname, int family, const void *address, int prefixlen, const void *broadcast) {
40 int retval;
41 size_t addr_size;
42 struct ifaddrmsg ifa;
43 struct nl_msg *msg = NULL;
44
45 addr_size = inet_family_size(family);
46 if(addr_size == 0) {
47 retval = -EAFNOSUPPORT;
48 goto cleanup;
49 }
50
51 memset(&ifa, 0, sizeof(ifa));
52 if (!(ifa.ifa_index = if_nametoindex(ifname))) {
53 retval = -ENODEV;
54 goto cleanup;
55 }
56 ifa.ifa_family = family;
57 ifa.ifa_prefixlen = prefixlen;
58 ifa.ifa_scope = RT_SCOPE_UNIVERSE;
59
60 msg = nlmsg_alloc_ifaddr(RTM_NEWADDR, NLM_F_ACK | NLM_F_REQUEST | NLM_F_CREATE | NLM_F_REPLACE, &ifa);
61 if(!msg) {
62 retval = -ENOMEM;
63 goto cleanup;
64 }
65
66 if(nla_put(msg, IFA_LOCAL, addr_size, address) < 0) {
67 retval = -ENOMEM;
68 goto cleanup;
69 }
70 if(family == AF_INET6) {
71 // AF_INET6 gets IFA_LOCAL + IFA_ADDRESS
72 if(nla_put(msg, IFA_ADDRESS, addr_size, address) < 0) {
73 retval = -ENOMEM;
74 goto cleanup;
75 }
76 } else if(family == AF_INET) {
77 // AF_INET gets IFA_LOCAL + IFA_BROADCAST
78 if(nla_put(msg, IFA_BROADCAST, addr_size, broadcast) < 0) {
79 retval = -ENOMEM;
80 goto cleanup;
81 }
82 } else {
83 retval = -EAFNOSUPPORT;
84 goto cleanup;
85 }
86
87 retval = netlink_sendrecv(msg);
88
89 cleanup:
90 if(msg)
91 nlmsg_free(msg);
92
93 return retval;
94 }
95
96 /* function: if_up
97 * sets interface link state to up and sets mtu, returns 0 on success and <0 on failure
98 * ifname - interface name to change
99 * mtu - new mtu
100 */
if_up(const char * ifname,int mtu)101 int if_up(const char *ifname, int mtu) {
102 int retval = -1;
103 struct ifinfomsg ifi;
104 struct nl_msg *msg = NULL;
105
106 memset(&ifi, 0, sizeof(ifi));
107 if (!(ifi.ifi_index = if_nametoindex(ifname))) {
108 retval = -ENODEV;
109 goto cleanup;
110 }
111 ifi.ifi_change = IFF_UP;
112 ifi.ifi_flags = IFF_UP;
113
114 msg = nlmsg_alloc_ifinfo(RTM_SETLINK, NLM_F_ACK | NLM_F_REQUEST | NLM_F_ROOT, &ifi);
115 if(!msg) {
116 retval = -ENOMEM;
117 goto cleanup;
118 }
119
120 if(nla_put(msg, IFLA_MTU, 4, &mtu) < 0) {
121 retval = -ENOMEM;
122 goto cleanup;
123 }
124
125 retval = netlink_sendrecv(msg);
126
127 cleanup:
128 if(msg)
129 nlmsg_free(msg);
130
131 return retval;
132 }
133
do_anycast_setsockopt(int sock,int what,struct in6_addr * addr,int ifindex)134 static int do_anycast_setsockopt(int sock, int what, struct in6_addr *addr, int ifindex) {
135 struct ipv6_mreq mreq = { *addr, ifindex };
136 char *optname;
137 int ret;
138
139 switch (what) {
140 DEBUG_OPTNAME(IPV6_JOIN_ANYCAST)
141 DEBUG_OPTNAME(IPV6_LEAVE_ANYCAST)
142 default:
143 optname = "???";
144 break;
145 }
146
147 ret = setsockopt(sock, SOL_IPV6, what, &mreq, sizeof(mreq));
148 if (ret) {
149 logmsg(ANDROID_LOG_ERROR, "%s: setsockopt(%s): %s", __func__, optname, strerror(errno));
150 }
151
152 return ret;
153 }
154
155 /* function: add_anycast_address
156 * adds an anycast IPv6 address to an interface, returns 0 on success and <0 on failure
157 * sock - the socket to add the address to
158 * addr - the IP address to add
159 * ifname - name of interface to add the address to
160 */
add_anycast_address(int sock,struct in6_addr * addr,const char * ifname)161 int add_anycast_address(int sock, struct in6_addr *addr, const char *ifname) {
162 int ifindex;
163
164 ifindex = if_nametoindex(ifname);
165 if (!ifindex) {
166 logmsg(ANDROID_LOG_ERROR, "%s: unknown ifindex for interface %s", __func__, ifname);
167 return -ENODEV;
168 }
169
170 return do_anycast_setsockopt(sock, IPV6_JOIN_ANYCAST, addr, ifindex);
171 }
172
173 /* function: del_anycast_address
174 * removes an anycast IPv6 address from the system, returns 0 on success and <0 on failure
175 * sock - the socket to remove from, must have had the address added via add_anycast_address
176 * addr - the IP address to remove
177 */
del_anycast_address(int sock,struct in6_addr * addr)178 int del_anycast_address(int sock, struct in6_addr *addr) {
179 return do_anycast_setsockopt(sock, IPV6_LEAVE_ANYCAST, addr, 0);
180 }
181