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+/* nit.c
+
+ Network Interface Tap (NIT) network interface code, by Ted Lemon
+ with one crucial tidbit of help from Stu Grossmen. */
+
+/*
+ * Copyright (c) 2004,2007,2009 by Internet Systems Consortium, Inc. ("ISC")
+ * Copyright (c) 1996-2003 by Internet Software Consortium
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
+ * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Internet Systems Consortium, Inc.
+ * 950 Charter Street
+ * Redwood City, CA 94063
+ * <info@isc.org>
+ * https://www.isc.org/
+ *
+ * This software has been written for Internet Systems Consortium
+ * by Ted Lemon in cooperation with Vixie Enterprises and Nominum, Inc.
+ * To learn more about Internet Systems Consortium, see
+ * ``https://www.isc.org/''. To learn more about Vixie Enterprises,
+ * see ``http://www.vix.com''. To learn more about Nominum, Inc., see
+ * ``http://www.nominum.com''.
+ */
+
+#include "dhcpd.h"
+#if defined (USE_NIT_SEND) || defined (USE_NIT_RECEIVE)
+#include <sys/ioctl.h>
+#include <sys/uio.h>
+
+#include <sys/time.h>
+#include <net/nit.h>
+#include <net/nit_if.h>
+#include <net/nit_pf.h>
+#include <net/nit_buf.h>
+#include <sys/stropts.h>
+#include <net/packetfilt.h>
+
+#include <netinet/in_systm.h>
+#include "includes/netinet/ip.h"
+#include "includes/netinet/udp.h"
+#include "includes/netinet/if_ether.h"
+
+/* Reinitializes the specified interface after an address change. This
+ is not required for packet-filter APIs. */
+
+#ifdef USE_NIT_SEND
+void if_reinitialize_send (info)
+ struct interface_info *info;
+{
+}
+#endif
+
+#ifdef USE_NIT_RECEIVE
+void if_reinitialize_receive (info)
+ struct interface_info *info;
+{
+}
+#endif
+
+/* Called by get_interface_list for each interface that's discovered.
+ Opens a packet filter for each interface and adds it to the select
+ mask. */
+
+int if_register_nit (info)
+ struct interface_info *info;
+{
+ int sock;
+ char filename[50];
+ struct ifreq ifr;
+ struct strioctl sio;
+
+ /* Open a NIT device */
+ sock = open ("/dev/nit", O_RDWR);
+ if (sock < 0)
+ log_fatal ("Can't open NIT device for %s: %m", info -> name);
+
+ /* Set the NIT device to point at this interface. */
+ sio.ic_cmd = NIOCBIND;
+ sio.ic_len = sizeof *(info -> ifp);
+ sio.ic_dp = (char *)(info -> ifp);
+ sio.ic_timout = INFTIM;
+ if (ioctl (sock, I_STR, &sio) < 0)
+ log_fatal ("Can't attach interface %s to nit device: %m",
+ info -> name);
+
+ /* Get the low-level address... */
+ sio.ic_cmd = SIOCGIFADDR;
+ sio.ic_len = sizeof ifr;
+ sio.ic_dp = (char *)&ifr;
+ sio.ic_timout = INFTIM;
+ if (ioctl (sock, I_STR, &sio) < 0)
+ log_fatal ("Can't get physical layer address for %s: %m",
+ info -> name);
+
+ /* XXX code below assumes ethernet interface! */
+ info -> hw_address.hlen = 7;
+ info -> hw_address.hbuf [0] = ARPHRD_ETHER;
+ memcpy (&info -> hw_address.hbuf [1],
+ ifr.ifr_ifru.ifru_addr.sa_data, 6);
+
+ if (ioctl (sock, I_PUSH, "pf") < 0)
+ log_fatal ("Can't push packet filter onto NIT for %s: %m",
+ info -> name);
+
+ return sock;
+}
+#endif /* USE_NIT_SEND || USE_NIT_RECEIVE */
+
+#ifdef USE_NIT_SEND
+void if_register_send (info)
+ struct interface_info *info;
+{
+ /* If we're using the nit API for sending and receiving,
+ we don't need to register this interface twice. */
+#ifndef USE_NIT_RECEIVE
+ struct packetfilt pf;
+ struct strioctl sio;
+
+ info -> wfdesc = if_register_nit (info);
+
+ pf.Pf_Priority = 0;
+ pf.Pf_FilterLen = 1;
+ pf.Pf_Filter [0] = ENF_PUSHZERO;
+
+ /* Set up an NIT filter that rejects everything... */
+ sio.ic_cmd = NIOCSETF;
+ sio.ic_len = sizeof pf;
+ sio.ic_dp = (char *)&pf;
+ sio.ic_timout = INFTIM;
+ if (ioctl (info -> wfdesc, I_STR, &sio) < 0)
+ log_fatal ("Can't set NIT filter: %m");
+#else
+ info -> wfdesc = info -> rfdesc;
+#endif
+ if (!quiet_interface_discovery)
+ log_info ("Sending on NIT/%s%s%s",
+ print_hw_addr (info -> hw_address.hbuf [0],
+ info -> hw_address.hlen - 1,
+ &info -> hw_address.hbuf [1]),
+ (info -> shared_network ? "/" : ""),
+ (info -> shared_network ?
+ info -> shared_network -> name : ""));
+}
+
+void if_deregister_send (info)
+ struct interface_info *info;
+{
+ /* If we're using the nit API for sending and receiving,
+ we don't need to register this interface twice. */
+#ifndef USE_NIT_RECEIVE
+ close (info -> wfdesc);
+#endif
+ info -> wfdesc = -1;
+ if (!quiet_interface_discovery)
+ log_info ("Disabling output on NIT/%s%s%s",
+ print_hw_addr (info -> hw_address.hbuf [0],
+ info -> hw_address.hlen - 1,
+ &info -> hw_address.hbuf [1]),
+ (info -> shared_network ? "/" : ""),
+ (info -> shared_network ?
+ info -> shared_network -> name : ""));
+}
+#endif /* USE_NIT_SEND */
+
+#ifdef USE_NIT_RECEIVE
+/* Packet filter program...
+ XXX Changes to the filter program may require changes to the constant
+ offsets used in if_register_send to patch the NIT program! XXX */
+
+void if_register_receive (info)
+ struct interface_info *info;
+{
+ int flag = 1;
+ u_int32_t x;
+ struct packetfilt pf;
+ struct strioctl sio;
+ u_int16_t addr [2];
+ struct timeval t;
+
+ /* Open a NIT device and hang it on this interface... */
+ info -> rfdesc = if_register_nit (info);
+
+ /* Set the snap length to 0, which means always take the whole
+ packet. */
+ x = 0;
+ if (ioctl (info -> rfdesc, NIOCSSNAP, &x) < 0)
+ log_fatal ("Can't set NIT snap length on %s: %m", info -> name);
+
+ /* Set the stream to byte stream mode */
+ if (ioctl (info -> rfdesc, I_SRDOPT, RMSGN) != 0)
+ log_info ("I_SRDOPT failed on %s: %m", info -> name);
+
+#if 0
+ /* Push on the chunker... */
+ if (ioctl (info -> rfdesc, I_PUSH, "nbuf") < 0)
+ log_fatal ("Can't push chunker onto NIT STREAM: %m");
+
+ /* Set the timeout to zero. */
+ t.tv_sec = 0;
+ t.tv_usec = 0;
+ if (ioctl (info -> rfdesc, NIOCSTIME, &t) < 0)
+ log_fatal ("Can't set chunk timeout: %m");
+#endif
+
+ /* Ask for no header... */
+ x = 0;
+ if (ioctl (info -> rfdesc, NIOCSFLAGS, &x) < 0)
+ log_fatal ("Can't set NIT flags on %s: %m", info -> name);
+
+ /* Set up the NIT filter program. */
+ /* XXX Unlike the BPF filter program, this one won't work if the
+ XXX IP packet is fragmented or if there are options on the IP
+ XXX header. */
+ pf.Pf_Priority = 0;
+ pf.Pf_FilterLen = 0;
+
+ pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHWORD + 6;
+ pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHLIT + ENF_CAND;
+ pf.Pf_Filter [pf.Pf_FilterLen++] = htons (ETHERTYPE_IP);
+ pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHLIT;
+ pf.Pf_Filter [pf.Pf_FilterLen++] = htons (IPPROTO_UDP);
+ pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHWORD + 11;
+ pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHLIT + ENF_AND;
+ pf.Pf_Filter [pf.Pf_FilterLen++] = htons (0xFF);
+ pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_CAND;
+ pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHWORD + 18;
+ pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHLIT + ENF_CAND;
+ pf.Pf_Filter [pf.Pf_FilterLen++] = local_port;
+
+ /* Install the filter... */
+ sio.ic_cmd = NIOCSETF;
+ sio.ic_len = sizeof pf;
+ sio.ic_dp = (char *)&pf;
+ sio.ic_timout = INFTIM;
+ if (ioctl (info -> rfdesc, I_STR, &sio) < 0)
+ log_fatal ("Can't set NIT filter on %s: %m", info -> name);
+
+ if (!quiet_interface_discovery)
+ log_info ("Listening on NIT/%s%s%s",
+ print_hw_addr (info -> hw_address.hbuf [0],
+ info -> hw_address.hlen - 1,
+ &info -> hw_address.hbuf [1]),
+ (info -> shared_network ? "/" : ""),
+ (info -> shared_network ?
+ info -> shared_network -> name : ""));
+}
+
+void if_deregister_receive (info)
+ struct interface_info *info;
+{
+ /* If we're using the nit API for sending and receiving,
+ we don't need to register this interface twice. */
+ close (info -> rfdesc);
+ info -> rfdesc = -1;
+
+ if (!quiet_interface_discovery)
+ log_info ("Disabling input on NIT/%s%s%s",
+ print_hw_addr (info -> hw_address.hbuf [0],
+ info -> hw_address.hlen - 1,
+ &info -> hw_address.hbuf [1]),
+ (info -> shared_network ? "/" : ""),
+ (info -> shared_network ?
+ info -> shared_network -> name : ""));
+}
+#endif /* USE_NIT_RECEIVE */
+
+#ifdef USE_NIT_SEND
+ssize_t send_packet (interface, packet, raw, len, from, to, hto)
+ struct interface_info *interface;
+ struct packet *packet;
+ struct dhcp_packet *raw;
+ size_t len;
+ struct in_addr from;
+ struct sockaddr_in *to;
+ struct hardware *hto;
+{
+ unsigned hbufp, ibufp;
+ double hh [16];
+ double ih [1536 / sizeof (double)];
+ unsigned char *buf = (unsigned char *)ih;
+ struct sockaddr *junk;
+ struct strbuf ctl, data;
+ struct sockaddr_in foo;
+ int result;
+
+ if (!strcmp (interface -> name, "fallback"))
+ return send_fallback (interface, packet, raw,
+ len, from, to, hto);
+
+ if (hto == NULL && interface->anycast_mac_addr.hlen)
+ hto = &interface->anycast_mac_addr;
+
+ /* Start with the sockaddr struct... */
+ junk = (struct sockaddr *)&hh [0];
+ hbufp = (((unsigned char *)&junk -> sa_data [0]) -
+ (unsigned char *)&hh[0]);
+ ibufp = 0;
+
+ /* Assemble the headers... */
+ assemble_hw_header (interface, (unsigned char *)junk, &hbufp, hto);
+ assemble_udp_ip_header (interface, buf, &ibufp,
+ from.s_addr, to -> sin_addr.s_addr,
+ to -> sin_port, (unsigned char *)raw, len);
+
+ /* Copy the data into the buffer (yuk). */
+ memcpy (buf + ibufp, raw, len);
+
+ /* Set up the sockaddr structure... */
+#if USE_SIN_LEN
+ junk -> sa_len = hbufp - 2; /* XXX */
+#endif
+ junk -> sa_family = AF_UNSPEC;
+
+ /* Set up the msg_buf structure... */
+ ctl.buf = (char *)&hh [0];
+ ctl.maxlen = ctl.len = hbufp;
+ data.buf = (char *)&ih [0];
+ data.maxlen = data.len = ibufp + len;
+
+ result = putmsg (interface -> wfdesc, &ctl, &data, 0);
+ if (result < 0)
+ log_error ("send_packet: %m");
+ return result;
+}
+#endif /* USE_NIT_SEND */
+
+#ifdef USE_NIT_RECEIVE
+ssize_t receive_packet (interface, buf, len, from, hfrom)
+ struct interface_info *interface;
+ unsigned char *buf;
+ size_t len;
+ struct sockaddr_in *from;
+ struct hardware *hfrom;
+{
+ int nread;
+ int length = 0;
+ int offset = 0;
+ unsigned char ibuf [1536];
+ int bufix = 0;
+ unsigned paylen;
+
+ length = read (interface -> rfdesc, ibuf, sizeof ibuf);
+ if (length <= 0)
+ return length;
+
+ /* Decode the physical header... */
+ offset = decode_hw_header (interface, ibuf, bufix, hfrom);
+
+ /* If a physical layer checksum failed (dunno of any
+ physical layer that supports this, but WTH), skip this
+ packet. */
+ if (offset < 0) {
+ return 0;
+ }
+
+ bufix += offset;
+ length -= offset;
+
+ /* Decode the IP and UDP headers... */
+ offset = decode_udp_ip_header (interface, ibuf, bufix,
+ from, length, &paylen);
+
+ /* If the IP or UDP checksum was bad, skip the packet... */
+ if (offset < 0)
+ return 0;
+
+ bufix += offset;
+ length -= offset;
+
+ if (length < paylen)
+ log_fatal("Internal inconsistency at %s:%d.", MDL);
+
+ /* Copy out the data in the packet... */
+ memcpy(buf, &ibuf[bufix], paylen);
+ return paylen;
+}
+
+int can_unicast_without_arp (ip)
+ struct interface_info *ip;
+{
+ return 1;
+}
+
+int can_receive_unicast_unconfigured (ip)
+ struct interface_info *ip;
+{
+ return 1;
+}
+
+int supports_multiple_interfaces (ip)
+ struct interface_info *ip;
+{
+ return 1;
+}
+
+void maybe_setup_fallback ()
+{
+ isc_result_t status;
+ struct interface_info *fbi = (struct interface_info *)0;
+ if (setup_fallback (&fbi, MDL)) {
+ if_register_fallback (fbi);
+ status = omapi_register_io_object ((omapi_object_t *)fbi,
+ if_readsocket, 0,
+ fallback_discard, 0, 0);
+ if (status != ISC_R_SUCCESS)
+ log_fatal ("Can't register I/O handle for %s: %s",
+ fbi -> name, isc_result_totext (status));
+ interface_dereference (&fbi, MDL);
+ }
+}
+#endif