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/* dnsmasq is Copyright (c) 2000-2009 Simon Kelley
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 dated June, 1991, or
(at your option) version 3 dated 29 June, 2007.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "dnsmasq.h"
#if defined(HAVE_BSD_NETWORK) || defined(HAVE_SOLARIS_NETWORK)
static struct iovec ifconf = {
.iov_base = NULL,
.iov_len = 0
};
static struct iovec ifreq = {
.iov_base = NULL,
.iov_len = 0
};
int iface_enumerate(void *parm, int (*ipv4_callback)(), int (*ipv6_callback)())
{
char *ptr;
struct ifreq *ifr;
struct ifconf ifc;
int fd, errsav, ret = 0;
int lastlen = 0;
size_t len = 0;
if ((fd = socket(PF_INET, SOCK_DGRAM, 0)) == -1)
return 0;
while(1)
{
len += 10*sizeof(struct ifreq);
if (!expand_buf(&ifconf, len))
goto err;
ifc.ifc_len = len;
ifc.ifc_buf = ifconf.iov_base;
if (ioctl(fd, SIOCGIFCONF, &ifc) == -1)
{
if (errno != EINVAL || lastlen != 0)
goto err;
}
else
{
if (ifc.ifc_len == lastlen)
break; /* got a big enough buffer now */
lastlen = ifc.ifc_len;
}
}
for (ptr = ifc.ifc_buf; ptr < (char *)(ifc.ifc_buf + ifc.ifc_len); ptr += len)
{
/* subsequent entries may not be aligned, so copy into
an aligned buffer to avoid nasty complaints about
unaligned accesses. */
len = sizeof(struct ifreq);
#ifdef HAVE_SOCKADDR_SA_LEN
ifr = (struct ifreq *)ptr;
if (ifr->ifr_addr.sa_len > sizeof(ifr->ifr_ifru))
len = ifr->ifr_addr.sa_len + offsetof(struct ifreq, ifr_ifru);
#endif
if (!expand_buf(&ifreq, len))
goto err;
ifr = (struct ifreq *)ifreq.iov_base;
memcpy(ifr, ptr, len);
if (ifr->ifr_addr.sa_family == AF_INET && ipv4_callback)
{
struct in_addr addr, netmask, broadcast;
broadcast.s_addr = 0;
addr = ((struct sockaddr_in *) &ifr->ifr_addr)->sin_addr;
if (ioctl(fd, SIOCGIFNETMASK, ifr) == -1)
continue;
netmask = ((struct sockaddr_in *) &ifr->ifr_addr)->sin_addr;
if (ioctl(fd, SIOCGIFBRDADDR, ifr) != -1)
broadcast = ((struct sockaddr_in *) &ifr->ifr_addr)->sin_addr;
if (!((*ipv4_callback)(addr,
(int)if_nametoindex(ifr->ifr_name),
netmask, broadcast,
parm)))
goto err;
}
#ifdef HAVE_IPV6
else if (ifr->ifr_addr.sa_family == AF_INET6 && ipv6_callback)
{
struct in6_addr *addr = &((struct sockaddr_in6 *)&ifr->ifr_addr)->sin6_addr;
/* voodoo to clear interface field in address */
if (!(daemon->options & OPT_NOWILD) && IN6_IS_ADDR_LINKLOCAL(addr))
{
addr->s6_addr[2] = 0;
addr->s6_addr[3] = 0;
}
if (!((*ipv6_callback)(addr,
(int)((struct sockaddr_in6 *)&ifr->ifr_addr)->sin6_scope_id,
(int)if_nametoindex(ifr->ifr_name),
parm)))
goto err;
}
#endif
}
ret = 1;
err:
errsav = errno;
close(fd);
errno = errsav;
return ret;
}
#endif
#if defined(HAVE_BSD_NETWORK) && defined(HAVE_DHCP)
#include <net/bpf.h>
void init_bpf(void)
{
int i = 0;
while (1)
{
/* useful size which happens to be sufficient */
if (expand_buf(&ifreq, sizeof(struct ifreq)))
{
sprintf(ifreq.iov_base, "/dev/bpf%d", i++);
if ((daemon->dhcp_raw_fd = open(ifreq.iov_base, O_RDWR, 0)) != -1)
return;
}
if (errno != EBUSY)
die(_("cannot create DHCP BPF socket: %s"), NULL, EC_BADNET);
}
}
void send_via_bpf(struct dhcp_packet *mess, size_t len,
struct in_addr iface_addr, struct ifreq *ifr)
{
/* Hairy stuff, packet either has to go to the
net broadcast or the destination can't reply to ARP yet,
but we do know the physical address.
Build the packet by steam, and send directly, bypassing
the kernel IP stack */
struct ether_header ether;
struct ip ip;
struct udphdr {
u16 uh_sport; /* source port */
u16 uh_dport; /* destination port */
u16 uh_ulen; /* udp length */
u16 uh_sum; /* udp checksum */
} udp;
u32 i, sum;
struct iovec iov[4];
/* Only know how to do ethernet on *BSD */
if (mess->htype != ARPHRD_ETHER || mess->hlen != ETHER_ADDR_LEN)
{
my_syslog(MS_DHCP | LOG_WARNING, _("DHCP request for unsupported hardware type (%d) received on %s"),
mess->htype, ifr->ifr_name);
return;
}
ifr->ifr_addr.sa_family = AF_LINK;
if (ioctl(daemon->dhcpfd, SIOCGIFADDR, ifr) < 0)
return;
memcpy(ether.ether_shost, LLADDR((struct sockaddr_dl *)&ifr->ifr_addr), ETHER_ADDR_LEN);
ether.ether_type = htons(ETHERTYPE_IP);
if (ntohs(mess->flags) & 0x8000)
{
memset(ether.ether_dhost, 255, ETHER_ADDR_LEN);
ip.ip_dst.s_addr = INADDR_BROADCAST;
}
else
{
memcpy(ether.ether_dhost, mess->chaddr, ETHER_ADDR_LEN);
ip.ip_dst.s_addr = mess->yiaddr.s_addr;
}
ip.ip_p = IPPROTO_UDP;
ip.ip_src.s_addr = iface_addr.s_addr;
ip.ip_len = htons(sizeof(struct ip) +
sizeof(struct udphdr) +
len) ;
ip.ip_hl = sizeof(struct ip) / 4;
ip.ip_v = IPVERSION;
ip.ip_tos = 0;
ip.ip_id = htons(0);
ip.ip_off = htons(0x4000); /* don't fragment */
ip.ip_ttl = IPDEFTTL;
ip.ip_sum = 0;
for (sum = 0, i = 0; i < sizeof(struct ip) / 2; i++)
sum += ((u16 *)&ip)[i];
while (sum>>16)
sum = (sum & 0xffff) + (sum >> 16);
ip.ip_sum = (sum == 0xffff) ? sum : ~sum;
udp.uh_sport = htons(daemon->dhcp_server_port);
udp.uh_dport = htons(daemon->dhcp_client_port);
if (len & 1)
((char *)mess)[len] = 0; /* for checksum, in case length is odd. */
udp.uh_sum = 0;
udp.uh_ulen = sum = htons(sizeof(struct udphdr) + len);
sum += htons(IPPROTO_UDP);
sum += ip.ip_src.s_addr & 0xffff;
sum += (ip.ip_src.s_addr >> 16) & 0xffff;
sum += ip.ip_dst.s_addr & 0xffff;
sum += (ip.ip_dst.s_addr >> 16) & 0xffff;
for (i = 0; i < sizeof(struct udphdr)/2; i++)
sum += ((u16 *)&udp)[i];
for (i = 0; i < (len + 1) / 2; i++)
sum += ((u16 *)mess)[i];
while (sum>>16)
sum = (sum & 0xffff) + (sum >> 16);
udp.uh_sum = (sum == 0xffff) ? sum : ~sum;
ioctl(daemon->dhcp_raw_fd, BIOCSETIF, ifr);
iov[0].iov_base = ðer;
iov[0].iov_len = sizeof(ether);
iov[1].iov_base = &ip;
iov[1].iov_len = sizeof(ip);
iov[2].iov_base = &udp;
iov[2].iov_len = sizeof(udp);
iov[3].iov_base = mess;
iov[3].iov_len = len;
while (writev(daemon->dhcp_raw_fd, iov, 4) == -1 && retry_send());
}
#endif
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