Annotation of embedaddon/dnsmasq/src/bpf.c, revision 1.1.1.5
1.1.1.5 ! misho 1: /* dnsmasq is Copyright (c) 2000-2022 Simon Kelley
1.1 misho 2:
3: This program is free software; you can redistribute it and/or modify
4: it under the terms of the GNU General Public License as published by
5: the Free Software Foundation; version 2 dated June, 1991, or
6: (at your option) version 3 dated 29 June, 2007.
7:
8: This program is distributed in the hope that it will be useful,
9: but WITHOUT ANY WARRANTY; without even the implied warranty of
10: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11: GNU General Public License for more details.
12:
13: You should have received a copy of the GNU General Public License
14: along with this program. If not, see <http://www.gnu.org/licenses/>.
15: */
16:
17: #include "dnsmasq.h"
18:
19: #if defined(HAVE_BSD_NETWORK) || defined(HAVE_SOLARIS_NETWORK)
20: #include <ifaddrs.h>
21:
22: #include <sys/param.h>
1.1.1.3 misho 23: #if defined(HAVE_BSD_NETWORK) && !defined(__APPLE__)
1.1 misho 24: #include <sys/sysctl.h>
1.1.1.3 misho 25: #endif
1.1.1.2 misho 26: #include <net/if.h>
1.1 misho 27: #include <net/route.h>
28: #include <net/if_dl.h>
29: #include <netinet/if_ether.h>
1.1.1.2 misho 30: #if defined(__FreeBSD__)
31: # include <net/if_var.h>
32: #endif
33: #include <netinet/in_var.h>
1.1.1.4 misho 34: #include <netinet6/in6_var.h>
1.1 misho 35:
36: #ifndef SA_SIZE
37: #define SA_SIZE(sa) \
38: ( (!(sa) || ((struct sockaddr *)(sa))->sa_len == 0) ? \
39: sizeof(long) : \
40: 1 + ( (((struct sockaddr *)(sa))->sa_len - 1) | (sizeof(long) - 1) ) )
41: #endif
42:
1.1.1.2 misho 43: #ifdef HAVE_BSD_NETWORK
44: static int del_family = 0;
1.1.1.4 misho 45: static union all_addr del_addr;
1.1.1.2 misho 46: #endif
47:
48: #if defined(HAVE_BSD_NETWORK) && !defined(__APPLE__)
49:
1.1 misho 50: int arp_enumerate(void *parm, int (*callback)())
51: {
52: int mib[6];
53: size_t needed;
54: char *next;
55: struct rt_msghdr *rtm;
56: struct sockaddr_inarp *sin2;
57: struct sockaddr_dl *sdl;
58: struct iovec buff;
59: int rc;
60:
61: buff.iov_base = NULL;
62: buff.iov_len = 0;
63:
64: mib[0] = CTL_NET;
65: mib[1] = PF_ROUTE;
66: mib[2] = 0;
67: mib[3] = AF_INET;
68: mib[4] = NET_RT_FLAGS;
69: #ifdef RTF_LLINFO
70: mib[5] = RTF_LLINFO;
71: #else
72: mib[5] = 0;
73: #endif
74: if (sysctl(mib, 6, NULL, &needed, NULL, 0) == -1 || needed == 0)
75: return 0;
76:
77: while (1)
78: {
79: if (!expand_buf(&buff, needed))
80: return 0;
81: if ((rc = sysctl(mib, 6, buff.iov_base, &needed, NULL, 0)) == 0 ||
82: errno != ENOMEM)
83: break;
84: needed += needed / 8;
85: }
86: if (rc == -1)
87: return 0;
88:
89: for (next = buff.iov_base ; next < (char *)buff.iov_base + needed; next += rtm->rtm_msglen)
90: {
91: rtm = (struct rt_msghdr *)next;
92: sin2 = (struct sockaddr_inarp *)(rtm + 1);
93: sdl = (struct sockaddr_dl *)((char *)sin2 + SA_SIZE(sin2));
94: if (!(*callback)(AF_INET, &sin2->sin_addr, LLADDR(sdl), sdl->sdl_alen, parm))
95: return 0;
96: }
97:
98: return 1;
99: }
1.1.1.2 misho 100: #endif /* defined(HAVE_BSD_NETWORK) && !defined(__APPLE__) */
1.1 misho 101:
102:
103: int iface_enumerate(int family, void *parm, int (*callback)())
104: {
105: struct ifaddrs *head, *addrs;
1.1.1.4 misho 106: int errsave, fd = -1, ret = 0;
1.1 misho 107:
108: if (family == AF_UNSPEC)
109: #if defined(HAVE_BSD_NETWORK) && !defined(__APPLE__)
110: return arp_enumerate(parm, callback);
111: #else
112: return 0; /* need code for Solaris and MacOS*/
113: #endif
114:
115: /* AF_LINK doesn't exist in Linux, so we can't use it in our API */
116: if (family == AF_LOCAL)
117: family = AF_LINK;
118:
119: if (getifaddrs(&head) == -1)
120: return 0;
121:
1.1.1.4 misho 122: #if defined(HAVE_BSD_NETWORK)
1.1.1.2 misho 123: if (family == AF_INET6)
124: fd = socket(PF_INET6, SOCK_DGRAM, 0);
125: #endif
126:
1.1 misho 127: for (addrs = head; addrs; addrs = addrs->ifa_next)
128: {
129: if (addrs->ifa_addr->sa_family == family)
130: {
131: int iface_index = if_nametoindex(addrs->ifa_name);
132:
1.1.1.2 misho 133: if (iface_index == 0 || !addrs->ifa_addr ||
134: (!addrs->ifa_netmask && family != AF_LINK))
1.1 misho 135: continue;
136:
137: if (family == AF_INET)
138: {
139: struct in_addr addr, netmask, broadcast;
140: addr = ((struct sockaddr_in *) addrs->ifa_addr)->sin_addr;
1.1.1.2 misho 141: #ifdef HAVE_BSD_NETWORK
1.1.1.4 misho 142: if (del_family == AF_INET && del_addr.addr4.s_addr == addr.s_addr)
1.1.1.2 misho 143: continue;
144: #endif
1.1 misho 145: netmask = ((struct sockaddr_in *) addrs->ifa_netmask)->sin_addr;
146: if (addrs->ifa_broadaddr)
147: broadcast = ((struct sockaddr_in *) addrs->ifa_broadaddr)->sin_addr;
148: else
149: broadcast.s_addr = 0;
1.1.1.2 misho 150: if (!((*callback)(addr, iface_index, NULL, netmask, broadcast, parm)))
1.1 misho 151: goto err;
152: }
153: else if (family == AF_INET6)
154: {
155: struct in6_addr *addr = &((struct sockaddr_in6 *) addrs->ifa_addr)->sin6_addr;
156: unsigned char *netmask = (unsigned char *) &((struct sockaddr_in6 *) addrs->ifa_netmask)->sin6_addr;
157: int scope_id = ((struct sockaddr_in6 *) addrs->ifa_addr)->sin6_scope_id;
158: int i, j, prefix = 0;
1.1.1.2 misho 159: u32 valid = 0xffffffff, preferred = 0xffffffff;
160: int flags = 0;
161: #ifdef HAVE_BSD_NETWORK
1.1.1.4 misho 162: if (del_family == AF_INET6 && IN6_ARE_ADDR_EQUAL(&del_addr.addr6, addr))
1.1.1.2 misho 163: continue;
164: #endif
165: #if defined(HAVE_BSD_NETWORK) && !defined(__APPLE__)
166: struct in6_ifreq ifr6;
167:
168: memset(&ifr6, 0, sizeof(ifr6));
1.1.1.4 misho 169: safe_strncpy(ifr6.ifr_name, addrs->ifa_name, sizeof(ifr6.ifr_name));
1.1.1.2 misho 170:
171: ifr6.ifr_addr = *((struct sockaddr_in6 *) addrs->ifa_addr);
172: if (fd != -1 && ioctl(fd, SIOCGIFAFLAG_IN6, &ifr6) != -1)
173: {
174: if (ifr6.ifr_ifru.ifru_flags6 & IN6_IFF_TENTATIVE)
175: flags |= IFACE_TENTATIVE;
176:
177: if (ifr6.ifr_ifru.ifru_flags6 & IN6_IFF_DEPRECATED)
178: flags |= IFACE_DEPRECATED;
179:
180: #ifdef IN6_IFF_TEMPORARY
181: if (!(ifr6.ifr_ifru.ifru_flags6 & (IN6_IFF_AUTOCONF | IN6_IFF_TEMPORARY)))
182: flags |= IFACE_PERMANENT;
183: #endif
184:
185: #ifdef IN6_IFF_PRIVACY
186: if (!(ifr6.ifr_ifru.ifru_flags6 & (IN6_IFF_AUTOCONF | IN6_IFF_PRIVACY)))
187: flags |= IFACE_PERMANENT;
188: #endif
189: }
1.1 misho 190:
1.1.1.2 misho 191: ifr6.ifr_addr = *((struct sockaddr_in6 *) addrs->ifa_addr);
192: if (fd != -1 && ioctl(fd, SIOCGIFALIFETIME_IN6, &ifr6) != -1)
193: {
194: valid = ifr6.ifr_ifru.ifru_lifetime.ia6t_vltime;
195: preferred = ifr6.ifr_ifru.ifru_lifetime.ia6t_pltime;
196: }
197: #endif
198:
1.1 misho 199: for (i = 0; i < IN6ADDRSZ; i++, prefix += 8)
200: if (netmask[i] != 0xff)
201: break;
1.1.1.2 misho 202:
1.1 misho 203: if (i != IN6ADDRSZ && netmask[i])
204: for (j = 7; j > 0; j--, prefix++)
205: if ((netmask[i] & (1 << j)) == 0)
206: break;
207:
208: /* voodoo to clear interface field in address */
209: if (!option_bool(OPT_NOWILD) && IN6_IS_ADDR_LINKLOCAL(addr))
210: {
211: addr->s6_addr[2] = 0;
212: addr->s6_addr[3] = 0;
1.1.1.2 misho 213: }
214:
215: if (!((*callback)(addr, prefix, scope_id, iface_index, flags,
216: (int) preferred, (int)valid, parm)))
217: goto err;
218: }
219:
1.1 misho 220: #ifdef HAVE_DHCP6
221: else if (family == AF_LINK)
222: {
223: /* Assume ethernet again here */
224: struct sockaddr_dl *sdl = (struct sockaddr_dl *) addrs->ifa_addr;
225: if (sdl->sdl_alen != 0 &&
226: !((*callback)(iface_index, ARPHRD_ETHER, LLADDR(sdl), sdl->sdl_alen, parm)))
227: goto err;
228: }
229: #endif
230: }
231: }
232:
233: ret = 1;
234:
235: err:
1.1.1.4 misho 236: errsave = errno;
1.1.1.2 misho 237: freeifaddrs(head);
238: if (fd != -1)
239: close(fd);
1.1.1.4 misho 240: errno = errsave;
1.1 misho 241:
242: return ret;
243: }
1.1.1.2 misho 244: #endif /* defined(HAVE_BSD_NETWORK) || defined(HAVE_SOLARIS_NETWORK) */
1.1 misho 245:
246:
247: #if defined(HAVE_BSD_NETWORK) && defined(HAVE_DHCP)
248: #include <net/bpf.h>
249:
250: void init_bpf(void)
251: {
252: int i = 0;
253:
254: while (1)
255: {
256: sprintf(daemon->dhcp_buff, "/dev/bpf%d", i++);
257: if ((daemon->dhcp_raw_fd = open(daemon->dhcp_buff, O_RDWR, 0)) != -1)
258: return;
259:
260: if (errno != EBUSY)
261: die(_("cannot create DHCP BPF socket: %s"), NULL, EC_BADNET);
262: }
263: }
264:
265: void send_via_bpf(struct dhcp_packet *mess, size_t len,
266: struct in_addr iface_addr, struct ifreq *ifr)
267: {
268: /* Hairy stuff, packet either has to go to the
269: net broadcast or the destination can't reply to ARP yet,
270: but we do know the physical address.
271: Build the packet by steam, and send directly, bypassing
272: the kernel IP stack */
273:
274: struct ether_header ether;
275: struct ip ip;
276: struct udphdr {
277: u16 uh_sport; /* source port */
278: u16 uh_dport; /* destination port */
279: u16 uh_ulen; /* udp length */
280: u16 uh_sum; /* udp checksum */
281: } udp;
282:
283: u32 i, sum;
284: struct iovec iov[4];
285:
286: /* Only know how to do ethernet on *BSD */
287: if (mess->htype != ARPHRD_ETHER || mess->hlen != ETHER_ADDR_LEN)
288: {
289: my_syslog(MS_DHCP | LOG_WARNING, _("DHCP request for unsupported hardware type (%d) received on %s"),
290: mess->htype, ifr->ifr_name);
291: return;
292: }
293:
294: ifr->ifr_addr.sa_family = AF_LINK;
295: if (ioctl(daemon->dhcpfd, SIOCGIFADDR, ifr) < 0)
296: return;
297:
298: memcpy(ether.ether_shost, LLADDR((struct sockaddr_dl *)&ifr->ifr_addr), ETHER_ADDR_LEN);
299: ether.ether_type = htons(ETHERTYPE_IP);
300:
301: if (ntohs(mess->flags) & 0x8000)
302: {
303: memset(ether.ether_dhost, 255, ETHER_ADDR_LEN);
304: ip.ip_dst.s_addr = INADDR_BROADCAST;
305: }
306: else
307: {
308: memcpy(ether.ether_dhost, mess->chaddr, ETHER_ADDR_LEN);
309: ip.ip_dst.s_addr = mess->yiaddr.s_addr;
310: }
311:
312: ip.ip_p = IPPROTO_UDP;
313: ip.ip_src.s_addr = iface_addr.s_addr;
314: ip.ip_len = htons(sizeof(struct ip) +
315: sizeof(struct udphdr) +
316: len) ;
317: ip.ip_hl = sizeof(struct ip) / 4;
318: ip.ip_v = IPVERSION;
319: ip.ip_tos = 0;
320: ip.ip_id = htons(0);
321: ip.ip_off = htons(0x4000); /* don't fragment */
322: ip.ip_ttl = IPDEFTTL;
323: ip.ip_sum = 0;
324: for (sum = 0, i = 0; i < sizeof(struct ip) / 2; i++)
325: sum += ((u16 *)&ip)[i];
326: while (sum>>16)
327: sum = (sum & 0xffff) + (sum >> 16);
328: ip.ip_sum = (sum == 0xffff) ? sum : ~sum;
329:
330: udp.uh_sport = htons(daemon->dhcp_server_port);
331: udp.uh_dport = htons(daemon->dhcp_client_port);
332: if (len & 1)
333: ((char *)mess)[len] = 0; /* for checksum, in case length is odd. */
334: udp.uh_sum = 0;
335: udp.uh_ulen = sum = htons(sizeof(struct udphdr) + len);
336: sum += htons(IPPROTO_UDP);
337: sum += ip.ip_src.s_addr & 0xffff;
338: sum += (ip.ip_src.s_addr >> 16) & 0xffff;
339: sum += ip.ip_dst.s_addr & 0xffff;
340: sum += (ip.ip_dst.s_addr >> 16) & 0xffff;
341: for (i = 0; i < sizeof(struct udphdr)/2; i++)
342: sum += ((u16 *)&udp)[i];
343: for (i = 0; i < (len + 1) / 2; i++)
344: sum += ((u16 *)mess)[i];
345: while (sum>>16)
346: sum = (sum & 0xffff) + (sum >> 16);
347: udp.uh_sum = (sum == 0xffff) ? sum : ~sum;
348:
349: ioctl(daemon->dhcp_raw_fd, BIOCSETIF, ifr);
350:
351: iov[0].iov_base = ðer;
352: iov[0].iov_len = sizeof(ether);
353: iov[1].iov_base = &ip;
354: iov[1].iov_len = sizeof(ip);
355: iov[2].iov_base = &udp;
356: iov[2].iov_len = sizeof(udp);
357: iov[3].iov_base = mess;
358: iov[3].iov_len = len;
359:
1.1.1.3 misho 360: while (retry_send(writev(daemon->dhcp_raw_fd, iov, 4)));
1.1 misho 361: }
362:
1.1.1.2 misho 363: #endif /* defined(HAVE_BSD_NETWORK) && defined(HAVE_DHCP) */
364:
365:
366: #ifdef HAVE_BSD_NETWORK
367:
368: void route_init(void)
369: {
370: /* AF_UNSPEC: all addr families */
371: daemon->routefd = socket(PF_ROUTE, SOCK_RAW, AF_UNSPEC);
372:
373: if (daemon->routefd == -1 || !fix_fd(daemon->routefd))
374: die(_("cannot create PF_ROUTE socket: %s"), NULL, EC_BADNET);
375: }
376:
1.1.1.3 misho 377: void route_sock(void)
1.1.1.2 misho 378: {
379: struct if_msghdr *msg;
380: int rc = recv(daemon->routefd, daemon->packet, daemon->packet_buff_sz, 0);
381:
382: if (rc < 4)
383: return;
384:
385: msg = (struct if_msghdr *)daemon->packet;
386:
387: if (rc < msg->ifm_msglen)
388: return;
389:
390: if (msg->ifm_version != RTM_VERSION)
391: {
392: static int warned = 0;
393: if (!warned)
394: {
395: my_syslog(LOG_WARNING, _("Unknown protocol version from route socket"));
396: warned = 1;
397: }
398: }
399: else if (msg->ifm_type == RTM_NEWADDR)
400: {
401: del_family = 0;
1.1.1.3 misho 402: queue_event(EVENT_NEWADDR);
1.1.1.2 misho 403: }
404: else if (msg->ifm_type == RTM_DELADDR)
405: {
406: /* There's a race in the kernel, such that if we run iface_enumerate() immediately
407: we get a DELADDR event, the deleted address still appears. Here we store the deleted address
408: in a static variable, and omit it from the set returned by iface_enumerate() */
409: int mask = ((struct ifa_msghdr *)msg)->ifam_addrs;
410: int maskvec[] = { RTA_DST, RTA_GATEWAY, RTA_NETMASK, RTA_GENMASK,
411: RTA_IFP, RTA_IFA, RTA_AUTHOR, RTA_BRD };
412: int of;
413: unsigned int i;
414:
415: for (i = 0, of = sizeof(struct ifa_msghdr); of < rc && i < sizeof(maskvec)/sizeof(maskvec[0]); i++)
416: if (mask & maskvec[i])
417: {
418: struct sockaddr *sa = (struct sockaddr *)((char *)msg + of);
419: size_t diff = (sa->sa_len != 0) ? sa->sa_len : sizeof(long);
420:
421: if (maskvec[i] == RTA_IFA)
422: {
423: del_family = sa->sa_family;
424: if (del_family == AF_INET)
1.1.1.4 misho 425: del_addr.addr4 = ((struct sockaddr_in *)sa)->sin_addr;
1.1.1.2 misho 426: else if (del_family == AF_INET6)
1.1.1.4 misho 427: del_addr.addr6 = ((struct sockaddr_in6 *)sa)->sin6_addr;
1.1.1.2 misho 428: else
429: del_family = 0;
430: }
431:
432: of += diff;
433: /* round up as needed */
434: if (diff & (sizeof(long) - 1))
435: of += sizeof(long) - (diff & (sizeof(long) - 1));
436: }
437:
1.1.1.3 misho 438: queue_event(EVENT_NEWADDR);
1.1.1.2 misho 439: }
440: }
441:
442: #endif /* HAVE_BSD_NETWORK */
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