src/bpf.c - thekelleys/dnsmasq - Gitiles

 /* dnsmasq is Copyright (c) 2000-2012 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)
 #include <ifaddrs.h>

 #if defined(HAVE_BSD_NETWORK) && !defined(__APPLE__)
 #include <sys/param.h>
 #include <sys/sysctl.h>
 #include <net/route.h>
 #include <net/if_dl.h>
 #include <netinet/if_ether.h>

 #ifndef SA_SIZE
 #define SA_SIZE(sa)                                             \
     (  (!(sa) || ((struct sockaddr *)(sa))->sa_len == 0) ?      \
         sizeof(long)            :                               \
         1 + ( (((struct sockaddr *)(sa))->sa_len - 1) | (sizeof(long) - 1) ) )
 #endif

 int arp_enumerate(void *parm, int (*callback)())
 {
   int mib[6];
   size_t needed;
   char *next;
   struct rt_msghdr *rtm;
   struct sockaddr_inarp *sin2;
   struct sockaddr_dl *sdl;
   struct iovec buff;
   int rc;

   buff.iov_base = NULL;
   buff.iov_len = 0;

   mib[0] = CTL_NET;
   mib[1] = PF_ROUTE;
   mib[2] = 0;
   mib[3] = AF_INET;
   mib[4] = NET_RT_FLAGS;
 #ifdef RTF_LLINFO
   mib[5] = RTF_LLINFO;
 #else
   mib[5] = 0;
 #endif
   if (sysctl(mib, 6, NULL, &needed, NULL, 0) == -1 || needed == 0)
     return 0;

   while (1)
     {
       if (!expand_buf(&buff, needed))
 	return 0;
       if ((rc = sysctl(mib, 6, buff.iov_base, &needed, NULL, 0)) == 0 ||
 	  errno != ENOMEM)
 	break;
       needed += needed / 8;
     }
   if (rc == -1)
     return 0;

   for (next = buff.iov_base ; next < (char *)buff.iov_base + needed; next += rtm->rtm_msglen)
     {
       rtm = (struct rt_msghdr *)next;
       sin2 = (struct sockaddr_inarp *)(rtm + 1);
       sdl = (struct sockaddr_dl *)((char *)sin2 + SA_SIZE(sin2));
       if (!(*callback)(AF_INET, &sin2->sin_addr, LLADDR(sdl), sdl->sdl_alen, parm))
 	return 0;
     }

   return 1;
 }
 #endif


 int iface_enumerate(int family, void *parm, int (*callback)())
 {
   struct ifaddrs *head, *addrs;
   int errsav, ret = 0;

   if (family == AF_UNSPEC)
 #if defined(HAVE_BSD_NETWORK) && !defined(__APPLE__)
     return  arp_enumerate(parm, callback);
 #else
   return 0; /* need code for Solaris and MacOS*/
 #endif

   /* AF_LINK doesn't exist in Linux, so we can't use it in our API */
   if (family == AF_LOCAL)
     family = AF_LINK;

   if (getifaddrs(&head) == -1)
     return 0;

   for (addrs = head; addrs; addrs = addrs->ifa_next)
     {
       if (addrs->ifa_addr->sa_family == family)
 	{
 	  int iface_index = if_nametoindex(addrs->ifa_name);

 	  if (iface_index == 0)
 	    continue;

 	  if (family == AF_INET)
 	    {
 	      struct in_addr addr, netmask, broadcast;
 	      addr = ((struct sockaddr_in *) addrs->ifa_addr)->sin_addr;
 	      netmask = ((struct sockaddr_in *) addrs->ifa_netmask)->sin_addr;
 	      broadcast = ((struct sockaddr_in *) addrs->ifa_broadaddr)->sin_addr;
 	      if (!((*callback)(addr, iface_index, netmask, broadcast, parm)))
 		goto err;
 	    }
 #ifdef HAVE_IPV6
 	  else if (family == AF_INET6)
 	    {
 	      struct in6_addr *addr = &((struct sockaddr_in6 *) addrs->ifa_addr)->sin6_addr;
 	      unsigned char *netmask = (unsigned char *) &((struct sockaddr_in6 *) addrs->ifa_netmask)->sin6_addr;
 	      int scope_id = ((struct sockaddr_in6 *) addrs->ifa_addr)->sin6_scope_id;
 	      int i, j, prefix = 0;

 	      for (i = 0; i < IN6ADDRSZ; i++, prefix += 8)
                 if (netmask[i] != 0xff)
 		  break;

 	      if (i != IN6ADDRSZ && netmask[i])
                 for (j = 7; j > 0; j--, prefix++)
 		  if ((netmask[i] & (1 << j)) == 0)
 		    break;

 	      /* voodoo to clear interface field in address */
 	      if (!option_bool(OPT_NOWILD) && IN6_IS_ADDR_LINKLOCAL(addr))
 		{
 		  addr->s6_addr[2] = 0;
 		  addr->s6_addr[3] = 0;
 		}

 	      /* preferred and valid times == forever until we known how to dtermine them. */
 	      if (!((*callback)(addr, prefix, scope_id, iface_index, 0, -1, -1, parm)))
 		goto err;
 	}
 #endif
 #ifdef HAVE_DHCP6
 	  else if (family == AF_LINK)
 	    {
 	      /* Assume ethernet again here */
 	      struct sockaddr_dl *sdl = (struct sockaddr_dl *) addrs->ifa_addr;
 	      if (sdl->sdl_alen != 0 &&
 		  !((*callback)(iface_index, ARPHRD_ETHER, LLADDR(sdl), sdl->sdl_alen, parm)))
 		goto err;
 	    }
 #endif
 	}
     }

   ret = 1;

  err:
   errsav = errno;
   freeifaddrs(head);
   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)
     {
       sprintf(daemon->dhcp_buff, "/dev/bpf%d", i++);
       if ((daemon->dhcp_raw_fd = open(daemon->dhcp_buff, 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 = &ether;
   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
	/* dnsmasq is Copyright (c) 2000-2012 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)
	#include <ifaddrs.h>

	#if defined(HAVE_BSD_NETWORK) && !defined(__APPLE__)
	#include <sys/param.h>
	#include <sys/sysctl.h>
	#include <net/route.h>
	#include <net/if_dl.h>
	#include <netinet/if_ether.h>

	#ifndef SA_SIZE
	#define SA_SIZE(sa) \
	( (!(sa) \|\| ((struct sockaddr *)(sa))->sa_len == 0) ? \
	sizeof(long) : \
	1 + ( (((struct sockaddr *)(sa))->sa_len - 1) \| (sizeof(long) - 1) ) )
	#endif

	int arp_enumerate(void parm, int (callback)())
	{
	int mib[6];
	size_t needed;
	char *next;
	struct rt_msghdr *rtm;
	struct sockaddr_inarp *sin2;
	struct sockaddr_dl *sdl;
	struct iovec buff;
	int rc;

	buff.iov_base = NULL;
	buff.iov_len = 0;

	mib[0] = CTL_NET;
	mib[1] = PF_ROUTE;
	mib[2] = 0;
	mib[3] = AF_INET;
	mib[4] = NET_RT_FLAGS;
	#ifdef RTF_LLINFO
	mib[5] = RTF_LLINFO;
	#else
	mib[5] = 0;
	#endif
	if (sysctl(mib, 6, NULL, &needed, NULL, 0) == -1 \|\| needed == 0)
	return 0;

	while (1)
	{
	if (!expand_buf(&buff, needed))
	return 0;
	if ((rc = sysctl(mib, 6, buff.iov_base, &needed, NULL, 0)) == 0 \|\|
	errno != ENOMEM)
	break;
	needed += needed / 8;
	}
	if (rc == -1)
	return 0;

	for (next = buff.iov_base ; next < (char *)buff.iov_base + needed; next += rtm->rtm_msglen)
	{
	rtm = (struct rt_msghdr *)next;
	sin2 = (struct sockaddr_inarp *)(rtm + 1);
	sdl = (struct sockaddr_dl )((char )sin2 + SA_SIZE(sin2));
	if (!(*callback)(AF_INET, &sin2->sin_addr, LLADDR(sdl), sdl->sdl_alen, parm))
	return 0;
	}

	return 1;
	}
	#endif


	int iface_enumerate(int family, void parm, int (callback)())
	{
	struct ifaddrs head, addrs;
	int errsav, ret = 0;

	if (family == AF_UNSPEC)
	#if defined(HAVE_BSD_NETWORK) && !defined(__APPLE__)
	return arp_enumerate(parm, callback);
	#else
	return 0; /* need code for Solaris and MacOS*/
	#endif

	/* AF_LINK doesn't exist in Linux, so we can't use it in our API */
	if (family == AF_LOCAL)
	family = AF_LINK;

	if (getifaddrs(&head) == -1)
	return 0;

	for (addrs = head; addrs; addrs = addrs->ifa_next)
	{
	if (addrs->ifa_addr->sa_family == family)
	{
	int iface_index = if_nametoindex(addrs->ifa_name);

	if (iface_index == 0)
	continue;

	if (family == AF_INET)
	{
	struct in_addr addr, netmask, broadcast;
	addr = ((struct sockaddr_in *) addrs->ifa_addr)->sin_addr;
	netmask = ((struct sockaddr_in *) addrs->ifa_netmask)->sin_addr;
	broadcast = ((struct sockaddr_in *) addrs->ifa_broadaddr)->sin_addr;
	if (!((*callback)(addr, iface_index, netmask, broadcast, parm)))
	goto err;
	}
	#ifdef HAVE_IPV6
	else if (family == AF_INET6)
	{
	struct in6_addr addr = &((struct sockaddr_in6 ) addrs->ifa_addr)->sin6_addr;
	unsigned char netmask = (unsigned char ) &((struct sockaddr_in6 *) addrs->ifa_netmask)->sin6_addr;
	int scope_id = ((struct sockaddr_in6 *) addrs->ifa_addr)->sin6_scope_id;
	int i, j, prefix = 0;

	for (i = 0; i < IN6ADDRSZ; i++, prefix += 8)
	if (netmask[i] != 0xff)
	break;

	if (i != IN6ADDRSZ && netmask[i])
	for (j = 7; j > 0; j--, prefix++)
	if ((netmask[i] & (1 << j)) == 0)
	break;

	/* voodoo to clear interface field in address */
	if (!option_bool(OPT_NOWILD) && IN6_IS_ADDR_LINKLOCAL(addr))
	{
	addr->s6_addr[2] = 0;
	addr->s6_addr[3] = 0;
	}

	/* preferred and valid times == forever until we known how to dtermine them. */
	if (!((*callback)(addr, prefix, scope_id, iface_index, 0, -1, -1, parm)))
	goto err;
	}
	#endif
	#ifdef HAVE_DHCP6
	else if (family == AF_LINK)
	{
	/* Assume ethernet again here */
	struct sockaddr_dl sdl = (struct sockaddr_dl ) addrs->ifa_addr;
	if (sdl->sdl_alen != 0 &&
	!((*callback)(iface_index, ARPHRD_ETHER, LLADDR(sdl), sdl->sdl_alen, parm)))
	goto err;
	}
	#endif
	}
	}

	ret = 1;

	err:
	errsav = errno;
	freeifaddrs(head);
	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)
	{
	sprintf(daemon->dhcp_buff, "/dev/bpf%d", i++);
	if ((daemon->dhcp_raw_fd = open(daemon->dhcp_buff, 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 = &ether;
	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