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 */
39int 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
89cleanup:
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 */
101int 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
127cleanup:
128  if(msg)
129    nlmsg_free(msg);
130
131  return retval;
132}
133
134static 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 */
161int add_anycast_address(int sock, struct in6_addr *addr, const char *ifname) {
162  int ifindex, s, ret;
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 */
178int del_anycast_address(int sock, struct in6_addr *addr) {
179  return do_anycast_setsockopt(sock, IPV6_LEAVE_ANYCAST, addr, 0);
180}
181