443 lines
12 KiB
C
443 lines
12 KiB
C
/* dnsmasq is Copyright (c) 2000-2024 Simon Kelley
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 dated June, 1991, or
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(at your option) version 3 dated 29 June, 2007.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "dnsmasq.h"
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#if defined(HAVE_BSD_NETWORK) || defined(HAVE_SOLARIS_NETWORK)
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#include <ifaddrs.h>
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#include <sys/param.h>
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#if defined(HAVE_BSD_NETWORK) && !defined(__APPLE__)
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#include <sys/sysctl.h>
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#endif
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#include <net/if.h>
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#include <net/route.h>
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#include <net/if_dl.h>
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#include <netinet/if_ether.h>
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#if defined(__FreeBSD__)
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# include <net/if_var.h>
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#endif
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#include <netinet/in_var.h>
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#include <netinet6/in6_var.h>
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#ifndef SA_SIZE
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#define SA_SIZE(sa) \
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( (!(sa) || ((struct sockaddr *)(sa))->sa_len == 0) ? \
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sizeof(long) : \
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1 + ( (((struct sockaddr *)(sa))->sa_len - 1) | (sizeof(long) - 1) ) )
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#endif
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#ifdef HAVE_BSD_NETWORK
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static int del_family = 0;
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static union all_addr del_addr;
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#endif
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#if defined(HAVE_BSD_NETWORK) && !defined(__APPLE__)
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int arp_enumerate(void *parm, int (*callback)())
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{
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int mib[6];
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size_t needed;
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char *next;
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struct rt_msghdr *rtm;
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struct sockaddr_inarp *sin2;
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struct sockaddr_dl *sdl;
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struct iovec buff;
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int rc;
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buff.iov_base = NULL;
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buff.iov_len = 0;
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mib[0] = CTL_NET;
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mib[1] = PF_ROUTE;
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mib[2] = 0;
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mib[3] = AF_INET;
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mib[4] = NET_RT_FLAGS;
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#ifdef RTF_LLINFO
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mib[5] = RTF_LLINFO;
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#else
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mib[5] = 0;
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#endif
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if (sysctl(mib, 6, NULL, &needed, NULL, 0) == -1 || needed == 0)
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return 0;
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while (1)
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{
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if (!expand_buf(&buff, needed))
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return 0;
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if ((rc = sysctl(mib, 6, buff.iov_base, &needed, NULL, 0)) == 0 ||
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errno != ENOMEM)
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break;
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needed += needed / 8;
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}
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if (rc == -1)
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return 0;
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for (next = buff.iov_base ; next < (char *)buff.iov_base + needed; next += rtm->rtm_msglen)
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{
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rtm = (struct rt_msghdr *)next;
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sin2 = (struct sockaddr_inarp *)(rtm + 1);
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sdl = (struct sockaddr_dl *)((char *)sin2 + SA_SIZE(sin2));
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if (!(*callback)(AF_INET, &sin2->sin_addr, LLADDR(sdl), sdl->sdl_alen, parm))
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return 0;
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}
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return 1;
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}
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#endif /* defined(HAVE_BSD_NETWORK) && !defined(__APPLE__) */
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int iface_enumerate(int family, void *parm, int (*callback)())
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{
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struct ifaddrs *head, *addrs;
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int errsave, fd = -1, ret = 0;
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if (family == AF_UNSPEC)
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#if defined(HAVE_BSD_NETWORK) && !defined(__APPLE__)
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return arp_enumerate(parm, callback);
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#else
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return 0; /* need code for Solaris and MacOS*/
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#endif
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/* AF_LINK doesn't exist in Linux, so we can't use it in our API */
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if (family == AF_LOCAL)
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family = AF_LINK;
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if (getifaddrs(&head) == -1)
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return 0;
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#if defined(HAVE_BSD_NETWORK)
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if (family == AF_INET6)
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fd = socket(PF_INET6, SOCK_DGRAM, 0);
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#endif
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for (addrs = head; addrs; addrs = addrs->ifa_next)
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{
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if (addrs->ifa_addr->sa_family == family)
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{
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int iface_index = if_nametoindex(addrs->ifa_name);
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if (iface_index == 0 || !addrs->ifa_addr ||
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(!addrs->ifa_netmask && family != AF_LINK))
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continue;
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if (family == AF_INET)
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{
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struct in_addr addr, netmask, broadcast;
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addr = ((struct sockaddr_in *) addrs->ifa_addr)->sin_addr;
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#ifdef HAVE_BSD_NETWORK
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if (del_family == AF_INET && del_addr.addr4.s_addr == addr.s_addr)
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continue;
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#endif
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netmask = ((struct sockaddr_in *) addrs->ifa_netmask)->sin_addr;
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if (addrs->ifa_broadaddr)
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broadcast = ((struct sockaddr_in *) addrs->ifa_broadaddr)->sin_addr;
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else
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broadcast.s_addr = 0;
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if (!((*callback)(addr, iface_index, NULL, netmask, broadcast, parm)))
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goto err;
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}
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else if (family == AF_INET6)
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{
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struct in6_addr *addr = &((struct sockaddr_in6 *) addrs->ifa_addr)->sin6_addr;
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unsigned char *netmask = (unsigned char *) &((struct sockaddr_in6 *) addrs->ifa_netmask)->sin6_addr;
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int scope_id = ((struct sockaddr_in6 *) addrs->ifa_addr)->sin6_scope_id;
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int i, j, prefix = 0;
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u32 valid = 0xffffffff, preferred = 0xffffffff;
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int flags = 0;
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#ifdef HAVE_BSD_NETWORK
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if (del_family == AF_INET6 && IN6_ARE_ADDR_EQUAL(&del_addr.addr6, addr))
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continue;
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#endif
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#if defined(HAVE_BSD_NETWORK) && !defined(__APPLE__)
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struct in6_ifreq ifr6;
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memset(&ifr6, 0, sizeof(ifr6));
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safe_strncpy(ifr6.ifr_name, addrs->ifa_name, sizeof(ifr6.ifr_name));
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ifr6.ifr_addr = *((struct sockaddr_in6 *) addrs->ifa_addr);
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if (fd != -1 && ioctl(fd, SIOCGIFAFLAG_IN6, &ifr6) != -1)
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{
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if (ifr6.ifr_ifru.ifru_flags6 & IN6_IFF_TENTATIVE)
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flags |= IFACE_TENTATIVE;
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if (ifr6.ifr_ifru.ifru_flags6 & IN6_IFF_DEPRECATED)
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flags |= IFACE_DEPRECATED;
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#ifdef IN6_IFF_TEMPORARY
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if (!(ifr6.ifr_ifru.ifru_flags6 & (IN6_IFF_AUTOCONF | IN6_IFF_TEMPORARY)))
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flags |= IFACE_PERMANENT;
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#endif
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#ifdef IN6_IFF_PRIVACY
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if (!(ifr6.ifr_ifru.ifru_flags6 & (IN6_IFF_AUTOCONF | IN6_IFF_PRIVACY)))
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flags |= IFACE_PERMANENT;
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#endif
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}
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ifr6.ifr_addr = *((struct sockaddr_in6 *) addrs->ifa_addr);
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if (fd != -1 && ioctl(fd, SIOCGIFALIFETIME_IN6, &ifr6) != -1)
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{
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valid = ifr6.ifr_ifru.ifru_lifetime.ia6t_vltime;
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preferred = ifr6.ifr_ifru.ifru_lifetime.ia6t_pltime;
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}
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#endif
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for (i = 0; i < IN6ADDRSZ; i++, prefix += 8)
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if (netmask[i] != 0xff)
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break;
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if (i != IN6ADDRSZ && netmask[i])
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for (j = 7; j > 0; j--, prefix++)
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if ((netmask[i] & (1 << j)) == 0)
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break;
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/* voodoo to clear interface field in address */
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if (!option_bool(OPT_NOWILD) && IN6_IS_ADDR_LINKLOCAL(addr))
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{
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addr->s6_addr[2] = 0;
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addr->s6_addr[3] = 0;
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}
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if (!((*callback)(addr, prefix, scope_id, iface_index, flags,
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(int) preferred, (int)valid, parm)))
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goto err;
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}
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#ifdef HAVE_DHCP6
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else if (family == AF_LINK)
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{
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/* Assume ethernet again here */
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struct sockaddr_dl *sdl = (struct sockaddr_dl *) addrs->ifa_addr;
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if (sdl->sdl_alen != 0 &&
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!((*callback)(iface_index, ARPHRD_ETHER, LLADDR(sdl), sdl->sdl_alen, parm)))
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goto err;
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}
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#endif
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}
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}
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ret = 1;
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err:
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errsave = errno;
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freeifaddrs(head);
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if (fd != -1)
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close(fd);
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errno = errsave;
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return ret;
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}
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#endif /* defined(HAVE_BSD_NETWORK) || defined(HAVE_SOLARIS_NETWORK) */
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#if defined(HAVE_BSD_NETWORK) && defined(HAVE_DHCP)
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#include <net/bpf.h>
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void init_bpf(void)
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{
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int i = 0;
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while (1)
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{
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sprintf(daemon->dhcp_buff, "/dev/bpf%d", i++);
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if ((daemon->dhcp_raw_fd = open(daemon->dhcp_buff, O_RDWR, 0)) != -1)
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return;
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if (errno != EBUSY)
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die(_("cannot create DHCP BPF socket: %s"), NULL, EC_BADNET);
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}
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}
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void send_via_bpf(struct dhcp_packet *mess, size_t len,
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struct in_addr iface_addr, struct ifreq *ifr)
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{
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/* Hairy stuff, packet either has to go to the
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net broadcast or the destination can't reply to ARP yet,
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but we do know the physical address.
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Build the packet by steam, and send directly, bypassing
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the kernel IP stack */
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struct ether_header ether;
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struct ip ip;
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struct udphdr {
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u16 uh_sport; /* source port */
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u16 uh_dport; /* destination port */
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u16 uh_ulen; /* udp length */
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u16 uh_sum; /* udp checksum */
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} udp;
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u32 i, sum;
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struct iovec iov[4];
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/* Only know how to do ethernet on *BSD */
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if (mess->htype != ARPHRD_ETHER || mess->hlen != ETHER_ADDR_LEN)
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{
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my_syslog(MS_DHCP | LOG_WARNING, _("DHCP request for unsupported hardware type (%d) received on %s"),
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mess->htype, ifr->ifr_name);
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return;
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}
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ifr->ifr_addr.sa_family = AF_LINK;
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if (ioctl(daemon->dhcpfd, SIOCGIFADDR, ifr) < 0)
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return;
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memcpy(ether.ether_shost, LLADDR((struct sockaddr_dl *)&ifr->ifr_addr), ETHER_ADDR_LEN);
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ether.ether_type = htons(ETHERTYPE_IP);
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if (ntohs(mess->flags) & 0x8000)
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{
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memset(ether.ether_dhost, 255, ETHER_ADDR_LEN);
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ip.ip_dst.s_addr = INADDR_BROADCAST;
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}
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else
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{
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memcpy(ether.ether_dhost, mess->chaddr, ETHER_ADDR_LEN);
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ip.ip_dst.s_addr = mess->yiaddr.s_addr;
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}
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ip.ip_p = IPPROTO_UDP;
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ip.ip_src.s_addr = iface_addr.s_addr;
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ip.ip_len = htons(sizeof(struct ip) +
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sizeof(struct udphdr) +
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len) ;
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ip.ip_hl = sizeof(struct ip) / 4;
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ip.ip_v = IPVERSION;
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ip.ip_tos = 0;
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ip.ip_id = htons(0);
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ip.ip_off = htons(0x4000); /* don't fragment */
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ip.ip_ttl = IPDEFTTL;
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ip.ip_sum = 0;
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for (sum = 0, i = 0; i < sizeof(struct ip) / 2; i++)
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sum += ((u16 *)&ip)[i];
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while (sum>>16)
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sum = (sum & 0xffff) + (sum >> 16);
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ip.ip_sum = (sum == 0xffff) ? sum : ~sum;
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udp.uh_sport = htons(daemon->dhcp_server_port);
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udp.uh_dport = htons(daemon->dhcp_client_port);
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if (len & 1)
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((char *)mess)[len] = 0; /* for checksum, in case length is odd. */
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udp.uh_sum = 0;
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udp.uh_ulen = sum = htons(sizeof(struct udphdr) + len);
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sum += htons(IPPROTO_UDP);
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sum += ip.ip_src.s_addr & 0xffff;
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sum += (ip.ip_src.s_addr >> 16) & 0xffff;
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sum += ip.ip_dst.s_addr & 0xffff;
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sum += (ip.ip_dst.s_addr >> 16) & 0xffff;
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for (i = 0; i < sizeof(struct udphdr)/2; i++)
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sum += ((u16 *)&udp)[i];
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for (i = 0; i < (len + 1) / 2; i++)
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sum += ((u16 *)mess)[i];
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while (sum>>16)
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sum = (sum & 0xffff) + (sum >> 16);
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udp.uh_sum = (sum == 0xffff) ? sum : ~sum;
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ioctl(daemon->dhcp_raw_fd, BIOCSETIF, ifr);
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iov[0].iov_base = ðer;
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iov[0].iov_len = sizeof(ether);
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iov[1].iov_base = &ip;
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iov[1].iov_len = sizeof(ip);
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iov[2].iov_base = &udp;
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iov[2].iov_len = sizeof(udp);
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iov[3].iov_base = mess;
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iov[3].iov_len = len;
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while (retry_send(writev(daemon->dhcp_raw_fd, iov, 4)));
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}
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#endif /* defined(HAVE_BSD_NETWORK) && defined(HAVE_DHCP) */
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#ifdef HAVE_BSD_NETWORK
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void route_init(void)
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{
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/* AF_UNSPEC: all addr families */
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daemon->routefd = socket(PF_ROUTE, SOCK_RAW, AF_UNSPEC);
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if (daemon->routefd == -1 || !fix_fd(daemon->routefd))
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die(_("cannot create PF_ROUTE socket: %s"), NULL, EC_BADNET);
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}
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void route_sock(void)
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{
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struct if_msghdr *msg;
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int rc = recv(daemon->routefd, daemon->packet, daemon->packet_buff_sz, 0);
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if (rc < 4)
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return;
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msg = (struct if_msghdr *)daemon->packet;
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if (rc < msg->ifm_msglen)
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return;
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if (msg->ifm_version != RTM_VERSION)
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{
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static int warned = 0;
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if (!warned)
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{
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my_syslog(LOG_WARNING, _("Unknown protocol version from route socket"));
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warned = 1;
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}
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}
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else if (msg->ifm_type == RTM_NEWADDR)
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{
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del_family = 0;
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queue_event(EVENT_NEWADDR);
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}
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else if (msg->ifm_type == RTM_DELADDR)
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{
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/* There's a race in the kernel, such that if we run iface_enumerate() immediately
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we get a DELADDR event, the deleted address still appears. Here we store the deleted address
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in a static variable, and omit it from the set returned by iface_enumerate() */
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int mask = ((struct ifa_msghdr *)msg)->ifam_addrs;
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int maskvec[] = { RTA_DST, RTA_GATEWAY, RTA_NETMASK, RTA_GENMASK,
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RTA_IFP, RTA_IFA, RTA_AUTHOR, RTA_BRD };
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int of;
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unsigned int i;
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for (i = 0, of = sizeof(struct ifa_msghdr); of < rc && i < sizeof(maskvec)/sizeof(maskvec[0]); i++)
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if (mask & maskvec[i])
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{
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struct sockaddr *sa = (struct sockaddr *)((char *)msg + of);
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size_t diff = (sa->sa_len != 0) ? sa->sa_len : sizeof(long);
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if (maskvec[i] == RTA_IFA)
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{
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del_family = sa->sa_family;
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if (del_family == AF_INET)
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del_addr.addr4 = ((struct sockaddr_in *)sa)->sin_addr;
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else if (del_family == AF_INET6)
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del_addr.addr6 = ((struct sockaddr_in6 *)sa)->sin6_addr;
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else
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del_family = 0;
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}
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of += diff;
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/* round up as needed */
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if (diff & (sizeof(long) - 1))
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of += sizeof(long) - (diff & (sizeof(long) - 1));
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}
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queue_event(EVENT_NEWADDR);
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}
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}
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#endif /* HAVE_BSD_NETWORK */
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