1/*
2 * sys-bsd.c - System-dependent procedures for setting up
3 * PPP interfaces on bsd-4.4-ish systems (including 386BSD, NetBSD, etc.)
4 *
5 * SPDX-License-Identifier: BSD-1-Clause
6 *
7 * Copyright (c) 1989 Carnegie Mellon University.
8 * All rights reserved.
9 *
10 * Redistribution and use in source and binary forms are permitted
11 * provided that the above copyright notice and this paragraph are
12 * duplicated in all such forms and that any documentation,
13 * advertising materials, and other materials related to such
14 * distribution and use acknowledge that the software was developed
15 * by Carnegie Mellon University.  The name of the
16 * University may not be used to endorse or promote products derived
17 * from this software without specific prior written permission.
18 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
20 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
21 *
22 * $FreeBSD$
23 *
24 */
25
26/*
27 * TODO:
28 */
29
30#include <sys/param.h>
31#include <sys/socket.h>
32#include <net/if.h>
33#include <net/route.h>
34#include <net/if_dl.h>
35#include <netinet/in.h>
36#include <netinet/if_ether.h>
37#include <arpa/inet.h>
38#include <netinet/in_systm.h>
39#include <netinet/ip.h>
40#include <sys/un.h>
41
42#include <errno.h>
43#include <stdio.h>
44#include <stdlib.h>
45#include <string.h>
46#include <sys/sysctl.h>
47#include <termios.h>
48#include <unistd.h>
49
50#include "layer.h"
51#include "mbuf.h"
52#include "log.h"
53#include "id.h"
54#include "timer.h"
55#include "fsm.h"
56#include "defs.h"
57#include "iplist.h"
58#include "throughput.h"
59#include "slcompress.h"
60#include "lqr.h"
61#include "hdlc.h"
62#include "ncpaddr.h"
63#include "ipcp.h"
64#include "ipv6cp.h"
65#include "descriptor.h"
66#include "lcp.h"
67#include "ccp.h"
68#include "link.h"
69#include "mp.h"
70#include "ncp.h"
71#include "filter.h"
72#ifndef NORADIUS
73#include "radius.h"
74#endif
75#include "bundle.h"
76#include "iface.h"
77#include "arp.h"
78
79/*
80 * SET_SA_FAMILY - set the sa_family field of a struct sockaddr,
81 * if it exists.
82 */
83#define SET_SA_FAMILY(addr, family)		\
84    memset((char *) &(addr), '\0', sizeof(addr));	\
85    addr.sa_family = (family); 			\
86    addr.sa_len = sizeof(addr);
87
88
89#if RTM_VERSION >= 3
90
91/*
92 * arp_SetProxy - Make a proxy ARP entry for the peer.
93 */
94static struct {
95  struct rt_msghdr hdr;
96  struct sockaddr_in dst;
97  struct sockaddr_dl hwa;
98  char extra[128];
99} arpmsg;
100
101static int
102arp_ProxySub(struct bundle *bundle, struct in_addr addr, int add)
103{
104  int routes;
105
106  /*
107   * Get the hardware address of an interface on the same subnet as our local
108   * address.
109   */
110
111  memset(&arpmsg, 0, sizeof arpmsg);
112  if (!arp_EtherAddr(addr, &arpmsg.hwa, 0)) {
113    log_Printf(LogWARN, "%s: Cannot determine ethernet address for proxy ARP\n",
114	       inet_ntoa(addr));
115    return 0;
116  }
117  routes = ID0socket(PF_ROUTE, SOCK_RAW, AF_INET);
118  if (routes < 0) {
119    log_Printf(LogERROR, "arp_SetProxy: opening routing socket: %s\n",
120	      strerror(errno));
121    return 0;
122  }
123  arpmsg.hdr.rtm_type = add ? RTM_ADD : RTM_DELETE;
124  arpmsg.hdr.rtm_flags = RTF_ANNOUNCE | RTF_HOST | RTF_STATIC | RTF_LLDATA;
125  arpmsg.hdr.rtm_version = RTM_VERSION;
126  arpmsg.hdr.rtm_seq = ++bundle->routing_seq;
127  arpmsg.hdr.rtm_addrs = RTA_DST | RTA_GATEWAY;
128  arpmsg.hdr.rtm_inits = RTV_EXPIRE;
129  arpmsg.dst.sin_len = sizeof(struct sockaddr_in);
130  arpmsg.dst.sin_family = AF_INET;
131  arpmsg.dst.sin_addr.s_addr = addr.s_addr;
132
133  arpmsg.hdr.rtm_msglen = (char *) &arpmsg.hwa - (char *) &arpmsg
134    + arpmsg.hwa.sdl_len;
135
136
137  if (ID0write(routes, &arpmsg, arpmsg.hdr.rtm_msglen) < 0 &&
138      !(!add && errno == ESRCH)) {
139    log_Printf(LogERROR, "%s proxy arp entry %s: %s\n",
140	add ? "Add" : "Delete", inet_ntoa(addr), strerror(errno));
141    close(routes);
142    return 0;
143  }
144  close(routes);
145  return 1;
146}
147
148int
149arp_SetProxy(struct bundle *bundle, struct in_addr addr)
150{
151  return (arp_ProxySub(bundle, addr, 1));
152}
153
154/*
155 * arp_ClearProxy - Delete the proxy ARP entry for the peer.
156 */
157int
158arp_ClearProxy(struct bundle *bundle, struct in_addr addr)
159{
160  return (arp_ProxySub(bundle, addr, 0));
161}
162
163#else				/* RTM_VERSION */
164
165/*
166 * arp_SetProxy - Make a proxy ARP entry for the peer.
167 */
168int
169arp_SetProxy(struct bundle *bundle, struct in_addr addr, int s)
170{
171  struct arpreq arpreq;
172  struct {
173    struct sockaddr_dl sdl;
174    char space[128];
175  }      dls;
176
177  memset(&arpreq, '\0', sizeof arpreq);
178
179  /*
180   * Get the hardware address of an interface on the same subnet as our local
181   * address.
182   */
183  if (!arp_EtherAddr(addr, &dls.sdl, 1)) {
184    log_Printf(LOG_PHASE_BIT, "Cannot determine ethernet address for "
185               "proxy ARP\n");
186    return 0;
187  }
188  arpreq.arp_ha.sa_len = sizeof(struct sockaddr);
189  arpreq.arp_ha.sa_family = AF_UNSPEC;
190  memcpy(arpreq.arp_ha.sa_data, LLADDR(&dls.sdl), dls.sdl.sdl_alen);
191  SET_SA_FAMILY(arpreq.arp_pa, AF_INET);
192  ((struct sockaddr_in *)&arpreq.arp_pa)->sin_addr.s_addr = addr.s_addr;
193  arpreq.arp_flags = ATF_PERM | ATF_PUBL;
194  if (ID0ioctl(s, SIOCSARP, (caddr_t) & arpreq) < 0) {
195    log_Printf(LogERROR, "arp_SetProxy: ioctl(SIOCSARP): %s\n",
196               strerror(errno));
197    return 0;
198  }
199  return 1;
200}
201
202/*
203 * arp_ClearProxy - Delete the proxy ARP entry for the peer.
204 */
205int
206arp_ClearProxy(struct bundle *bundle, struct in_addr addr, int s)
207{
208  struct arpreq arpreq;
209
210  memset(&arpreq, '\0', sizeof arpreq);
211  SET_SA_FAMILY(arpreq.arp_pa, AF_INET);
212  ((struct sockaddr_in *)&arpreq.arp_pa)->sin_addr.s_addr = addr.s_addr;
213  if (ID0ioctl(s, SIOCDARP, (caddr_t) & arpreq) < 0) {
214    log_Printf(LogERROR, "arp_ClearProxy: ioctl(SIOCDARP): %s\n",
215               strerror(errno));
216    return 0;
217  }
218  return 1;
219}
220
221#endif				/* RTM_VERSION */
222
223
224/*
225 * arp_EtherAddr - get the hardware address of an interface on the
226 * the same subnet as ipaddr.
227 */
228
229int
230arp_EtherAddr(struct in_addr ipaddr, struct sockaddr_dl *hwaddr,
231              int verbose)
232{
233  int mib[6], skip;
234  size_t needed;
235  char *buf, *ptr, *end;
236  struct if_msghdr *ifm;
237  struct ifa_msghdr *ifam;
238  struct sockaddr_dl *dl;
239  struct sockaddr *sa[RTAX_MAX];
240
241  mib[0] = CTL_NET;
242  mib[1] = PF_ROUTE;
243  mib[2] = 0;
244  mib[3] = 0;
245  mib[4] = NET_RT_IFLIST;
246  mib[5] = 0;
247
248  if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) {
249    log_Printf(LogERROR, "arp_EtherAddr: sysctl: estimate: %s\n",
250              strerror(errno));
251    return 0;
252  }
253
254  if ((buf = malloc(needed)) == NULL)
255    return 0;
256
257  if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
258    free(buf);
259    return 0;
260  }
261  end = buf + needed;
262
263  ptr = buf;
264  while (ptr < end) {
265    ifm = (struct if_msghdr *)ptr;		/* On if_msghdr */
266    if (ifm->ifm_type != RTM_IFINFO)
267      break;
268    dl = (struct sockaddr_dl *)(ifm + 1);	/* Single _dl at end */
269    skip = (ifm->ifm_flags & (IFF_UP | IFF_BROADCAST | IFF_POINTOPOINT |
270            IFF_NOARP | IFF_LOOPBACK)) != (IFF_UP | IFF_BROADCAST);
271    ptr += ifm->ifm_msglen;			/* First ifa_msghdr */
272    while (ptr < end) {
273      ifam = (struct ifa_msghdr *)ptr;	/* Next ifa_msghdr (alias) */
274      if (ifam->ifam_type != RTM_NEWADDR)	/* finished ? */
275        break;
276      ptr += ifam->ifam_msglen;
277      if (skip || (ifam->ifam_addrs & (RTA_NETMASK|RTA_IFA)) !=
278          (RTA_NETMASK|RTA_IFA))
279        continue;
280      /* Found a candidate.  Do the addresses match ? */
281      if (log_IsKept(LogDEBUG) &&
282          ptr == (char *)ifm + ifm->ifm_msglen + ifam->ifam_msglen)
283        log_Printf(LogDEBUG, "%.*s interface is a candidate for proxy\n",
284                  dl->sdl_nlen, dl->sdl_data);
285
286      iface_ParseHdr(ifam, sa);
287
288      if (sa[RTAX_IFA]->sa_family == AF_INET) {
289        struct sockaddr_in *ifa, *netmask;
290
291        ifa = (struct sockaddr_in *)sa[RTAX_IFA];
292        netmask = (struct sockaddr_in *)sa[RTAX_NETMASK];
293
294        if (log_IsKept(LogDEBUG)) {
295          char a[16];
296
297          strncpy(a, inet_ntoa(netmask->sin_addr), sizeof a - 1);
298          a[sizeof a - 1] = '\0';
299          log_Printf(LogDEBUG, "Check addr %s, mask %s\n",
300                     inet_ntoa(ifa->sin_addr), a);
301        }
302
303        if ((ifa->sin_addr.s_addr & netmask->sin_addr.s_addr) ==
304            (ipaddr.s_addr & netmask->sin_addr.s_addr)) {
305          log_Printf(verbose ? LogPHASE : LogDEBUG,
306                     "Found interface %.*s for %s\n", dl->sdl_nlen,
307                     dl->sdl_data, inet_ntoa(ipaddr));
308          memcpy(hwaddr, dl, dl->sdl_len);
309          free(buf);
310          return 1;
311        }
312      }
313    }
314  }
315  free(buf);
316
317  return 0;
318}
319