3
BPF socket interface code, originally contributed by Archie Cobbs. */
6
* Copyright (c) 2004,2007 by Internet Systems Consortium, Inc. ("ISC")
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* Copyright (c) 1996-2003 by Internet Software Consortium
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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* Internet Systems Consortium, Inc.
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* Redwood City, CA 94063
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* This software was contributed to Internet Systems Consortium
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* Patches for FDDI support on Digital Unix were written by Bill
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* Stapleton, and maintained for a while by Mike Meredith before he
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* managed to get me to integrate them.
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#if defined (USE_BPF_SEND) || defined (USE_BPF_RECEIVE) \
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|| defined (USE_LPF_RECEIVE)
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# if defined (USE_LPF_RECEIVE)
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# include <asm/types.h>
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# include <linux/filter.h>
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# define bpf_insn sock_filter /* Linux: dare to be gratuitously different. */
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# include <sys/ioctl.h>
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# include <net/if_types.h>
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# if defined (NEED_OSF_PFILT_HACKS)
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# include <net/pfilt.h>
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#include <netinet/in_systm.h>
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#include "includes/netinet/ip.h"
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#include "includes/netinet/udp.h"
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#include "includes/netinet/if_ether.h"
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#ifdef USE_BPF_RECEIVE
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/* Reinitializes the specified interface after an address change. This
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is not required for packet-filter APIs. */
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void if_reinitialize_send (info)
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struct interface_info *info;
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#ifdef USE_BPF_RECEIVE
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void if_reinitialize_receive (info)
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struct interface_info *info;
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/* Called by get_interface_list for each interface that's discovered.
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Opens a packet filter for each interface and adds it to the select
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#if defined (USE_BPF_SEND) || defined (USE_BPF_RECEIVE)
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int if_register_bpf (info)
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struct interface_info *info;
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/* Open a BPF device */
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/* %Audit% 31 bytes max. %2004.06.17,Safe% */
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sprintf(filename, BPF_FORMAT, b);
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sock = open (filename, O_RDWR, 0);
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log_fatal ("No bpf devices.%s%s%s",
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" Please read the README",
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" section for your operating",
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log_fatal ("Can't find free bpf: %m");
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/* Set the BPF device to point at this interface. */
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if (ioctl (sock, BIOCSETIF, info -> ifp) < 0)
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log_fatal ("Can't attach interface %s to bpf device %s: %m",
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info -> name, filename);
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get_hw_addr(info->name, &info->hw_address);
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#endif /* USE_BPF_SEND || USE_BPF_RECEIVE */
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void if_register_send (info)
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struct interface_info *info;
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/* If we're using the bpf API for sending and receiving,
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we don't need to register this interface twice. */
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#ifndef USE_BPF_RECEIVE
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info -> wfdesc = if_register_bpf (info, interface);
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info -> wfdesc = info -> rfdesc;
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if (!quiet_interface_discovery)
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log_info ("Sending on BPF/%s/%s%s%s",
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print_hw_addr (info -> hw_address.hbuf [0],
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info -> hw_address.hlen - 1,
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&info -> hw_address.hbuf [1]),
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(info -> shared_network ? "/" : ""),
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(info -> shared_network ?
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info -> shared_network -> name : ""));
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void if_deregister_send (info)
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struct interface_info *info;
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/* If we're using the bpf API for sending and receiving,
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we don't need to register this interface twice. */
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#ifndef USE_BPF_RECEIVE
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close (info -> wfdesc);
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if (!quiet_interface_discovery)
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log_info ("Disabling output on BPF/%s/%s%s%s",
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print_hw_addr (info -> hw_address.hbuf [0],
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info -> hw_address.hlen - 1,
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&info -> hw_address.hbuf [1]),
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(info -> shared_network ? "/" : ""),
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(info -> shared_network ?
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info -> shared_network -> name : ""));
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#endif /* USE_BPF_SEND */
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#if defined (USE_BPF_RECEIVE) || defined (USE_LPF_RECEIVE)
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/* Packet filter program...
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XXX Changes to the filter program may require changes to the constant
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offsets used in if_register_send to patch the BPF program! XXX */
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struct bpf_insn dhcp_bpf_filter [] = {
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/* Make sure this is an IP packet... */
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BPF_STMT (BPF_LD + BPF_H + BPF_ABS, 12),
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BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_IP, 0, 8),
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/* Make sure it's a UDP packet... */
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BPF_STMT (BPF_LD + BPF_B + BPF_ABS, 23),
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BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 0, 6),
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/* Make sure this isn't a fragment... */
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BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 20),
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BPF_JUMP(BPF_JMP + BPF_JSET + BPF_K, 0x1fff, 4, 0),
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/* Get the IP header length... */
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BPF_STMT (BPF_LDX + BPF_B + BPF_MSH, 14),
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/* Make sure it's to the right port... */
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BPF_STMT (BPF_LD + BPF_H + BPF_IND, 16),
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BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, 67, 0, 1), /* patch */
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/* If we passed all the tests, ask for the whole packet. */
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BPF_STMT(BPF_RET+BPF_K, (u_int)-1),
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/* Otherwise, drop it. */
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BPF_STMT(BPF_RET+BPF_K, 0),
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#if defined (DEC_FDDI)
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struct bpf_insn *bpf_fddi_filter;
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int dhcp_bpf_filter_len = sizeof dhcp_bpf_filter / sizeof (struct bpf_insn);
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#if defined (HAVE_TR_SUPPORT)
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struct bpf_insn dhcp_bpf_tr_filter [] = {
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/* accept all token ring packets due to variable length header */
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/* if we want to get clever, insert the program here */
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/* If we passed all the tests, ask for the whole packet. */
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BPF_STMT(BPF_RET+BPF_K, (u_int)-1),
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/* Otherwise, drop it. */
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BPF_STMT(BPF_RET+BPF_K, 0),
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int dhcp_bpf_tr_filter_len = (sizeof dhcp_bpf_tr_filter /
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sizeof (struct bpf_insn));
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#endif /* HAVE_TR_SUPPORT */
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#endif /* USE_LPF_RECEIVE || USE_BPF_RECEIVE */
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#if defined (USE_BPF_RECEIVE)
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void if_register_receive (info)
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struct interface_info *info;
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struct bpf_version v;
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struct bpf_program p;
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#ifdef NEED_OSF_PFILT_HACKS
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#endif /* DEC_FDDI */
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/* Open a BPF device and hang it on this interface... */
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info -> rfdesc = if_register_bpf (info);
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/* Make sure the BPF version is in range... */
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if (ioctl (info -> rfdesc, BIOCVERSION, &v) < 0)
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log_fatal ("Can't get BPF version: %m");
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if (v.bv_major != BPF_MAJOR_VERSION ||
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v.bv_minor < BPF_MINOR_VERSION)
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log_fatal ("BPF version mismatch - recompile DHCP!");
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/* Set immediate mode so that reads return as soon as a packet
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comes in, rather than waiting for the input buffer to fill with
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if (ioctl (info -> rfdesc, BIOCIMMEDIATE, &flag) < 0)
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log_fatal ("Can't set immediate mode on bpf device: %m");
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#ifdef NEED_OSF_PFILT_HACKS
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/* Allow the copyall flag to be set... */
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if (ioctl(info -> rfdesc, EIOCALLOWCOPYALL, &flag) < 0)
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log_fatal ("Can't set ALLOWCOPYALL: %m");
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/* Clear all the packet filter mode bits first... */
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if (ioctl (info -> rfdesc, EIOCMBIS, &bits) < 0)
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log_fatal ("Can't clear pfilt bits: %m");
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/* Set the ENBATCH, ENCOPYALL, ENBPFHDR bits... */
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bits = ENBATCH | ENCOPYALL | ENBPFHDR;
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if (ioctl (info -> rfdesc, EIOCMBIS, &bits) < 0)
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log_fatal ("Can't set ENBATCH|ENCOPYALL|ENBPFHDR: %m");
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/* Get the required BPF buffer length from the kernel. */
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if (ioctl (info -> rfdesc, BIOCGBLEN, &info -> rbuf_max) < 0)
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log_fatal ("Can't get bpf buffer length: %m");
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info -> rbuf = dmalloc (info -> rbuf_max, MDL);
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log_fatal ("Can't allocate %ld bytes for bpf input buffer.",
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(long)(info -> rbuf_max));
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info -> rbuf_offset = 0;
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info -> rbuf_len = 0;
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/* Set up the bpf filter program structure. */
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p.bf_len = dhcp_bpf_filter_len;
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/* See if this is an FDDI interface, flag it for later. */
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if (ioctl(info -> rfdesc, BIOCGDLT, &link_layer) >= 0 &&
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link_layer == DLT_FDDI) {
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if (!bpf_fddi_filter) {
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bpf_fddi_filter = dmalloc (sizeof bpf_fddi_filter,
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if (!bpf_fddi_filter)
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log_fatal ("No memory for FDDI filter.");
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memcpy (bpf_fddi_filter,
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dhcp_bpf_filter, sizeof dhcp_bpf_filter);
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/* Patch the BPF program to account for the difference
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in length between ethernet headers (14), FDDI and
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802.2 headers (16 +8=24, +10).
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XXX changes to filter program may require changes to
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XXX the insn number(s) used below! */
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bpf_fddi_filter[0].k += 10;
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bpf_fddi_filter[2].k += 10;
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bpf_fddi_filter[4].k += 10;
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bpf_fddi_filter[6].k += 10;
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bpf_fddi_filter[7].k += 10;
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p.bf_insns = bpf_fddi_filter;
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#endif /* DEC_FDDI */
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p.bf_insns = dhcp_bpf_filter;
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/* Patch the server port into the BPF program...
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XXX changes to filter program may require changes
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to the insn number(s) used below! XXX */
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dhcp_bpf_filter [8].k = ntohs (local_port);
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if (ioctl (info -> rfdesc, BIOCSETF, &p) < 0)
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log_fatal ("Can't install packet filter program: %m");
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if (!quiet_interface_discovery)
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log_info ("Listening on BPF/%s/%s%s%s",
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print_hw_addr (info -> hw_address.hbuf [0],
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info -> hw_address.hlen - 1,
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&info -> hw_address.hbuf [1]),
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(info -> shared_network ? "/" : ""),
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(info -> shared_network ?
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info -> shared_network -> name : ""));
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void if_deregister_receive (info)
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struct interface_info *info;
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close (info -> rfdesc);
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if (!quiet_interface_discovery)
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log_info ("Disabling input on BPF/%s/%s%s%s",
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print_hw_addr (info -> hw_address.hbuf [0],
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info -> hw_address.hlen - 1,
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&info -> hw_address.hbuf [1]),
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(info -> shared_network ? "/" : ""),
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(info -> shared_network ?
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info -> shared_network -> name : ""));
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#endif /* USE_BPF_RECEIVE */
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ssize_t send_packet (interface, packet, raw, len, from, to, hto)
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struct interface_info *interface;
348
struct packet *packet;
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struct dhcp_packet *raw;
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struct sockaddr_in *to;
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struct hardware *hto;
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unsigned hbufp = 0, ibufp = 0;
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struct iovec iov [3];
361
if (!strcmp (interface -> name, "fallback"))
362
return send_fallback (interface, packet, raw,
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/* Assemble the headers... */
366
assemble_hw_header (interface, (unsigned char *)hw, &hbufp, hto);
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assemble_udp_ip_header (interface,
368
(unsigned char *)ip, &ibufp, from.s_addr,
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to -> sin_addr.s_addr, to -> sin_port,
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(unsigned char *)raw, len);
373
iov [0].iov_base = ((char *)hw);
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iov [0].iov_len = hbufp;
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iov [1].iov_base = ((char *)ip);
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iov [1].iov_len = ibufp;
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iov [2].iov_base = (char *)raw;
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iov [2].iov_len = len;
380
result = writev(interface -> wfdesc, iov, 3);
382
log_error ("send_packet: %m");
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#endif /* USE_BPF_SEND */
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#ifdef USE_BPF_RECEIVE
388
ssize_t receive_packet (interface, buf, len, from, hfrom)
389
struct interface_info *interface;
392
struct sockaddr_in *from;
393
struct hardware *hfrom;
400
/* All this complexity is because BPF doesn't guarantee
401
that only one packet will be returned at a time. We're
402
getting what we deserve, though - this is a terrible abuse
403
of the BPF interface. Sigh. */
405
/* Process packets until we get one we can return or until we've
406
done a read and gotten nothing we can return... */
409
/* If the buffer is empty, fill it. */
410
if (interface -> rbuf_offset == interface -> rbuf_len) {
411
length = read (interface -> rfdesc,
413
(size_t)interface -> rbuf_max);
416
if (errno == ENXIO) {
420
dhcp_interface_remove
421
((omapi_object_t *)interface,
422
(omapi_object_t *)0);
426
interface -> rbuf_offset = 0;
427
interface -> rbuf_len = BPF_WORDALIGN (length);
430
/* If there isn't room for a whole bpf header, something went
431
wrong, but we'll ignore it and hope it goes away... XXX */
432
if (interface -> rbuf_len -
433
interface -> rbuf_offset < sizeof hdr) {
434
interface -> rbuf_offset = interface -> rbuf_len;
438
/* Copy out a bpf header... */
439
memcpy (&hdr, &interface -> rbuf [interface -> rbuf_offset],
442
/* If the bpf header plus data doesn't fit in what's left
443
of the buffer, stick head in sand yet again... */
444
if (interface -> rbuf_offset +
445
hdr.bh_hdrlen + hdr.bh_caplen > interface -> rbuf_len) {
446
interface -> rbuf_offset = interface -> rbuf_len;
450
/* If the captured data wasn't the whole packet, or if
451
the packet won't fit in the input buffer, all we
452
can do is drop it. */
453
if (hdr.bh_caplen != hdr.bh_datalen) {
454
interface -> rbuf_offset =
455
BPF_WORDALIGN (interface -> rbuf_offset +
456
hdr.bh_hdrlen + hdr.bh_caplen);
460
/* Skip over the BPF header... */
461
interface -> rbuf_offset += hdr.bh_hdrlen;
463
/* Decode the physical header... */
464
offset = decode_hw_header (interface,
466
interface -> rbuf_offset,
469
/* If a physical layer checksum failed (dunno of any
470
physical layer that supports this, but WTH), skip this
473
interface -> rbuf_offset =
474
BPF_WORDALIGN (interface -> rbuf_offset +
478
interface -> rbuf_offset += offset;
479
hdr.bh_caplen -= offset;
481
/* Decode the IP and UDP headers... */
482
offset = decode_udp_ip_header (interface,
484
interface -> rbuf_offset,
485
from, hdr.bh_caplen, &paylen);
487
/* If the IP or UDP checksum was bad, skip the packet... */
489
interface -> rbuf_offset =
490
BPF_WORDALIGN (interface -> rbuf_offset +
494
interface -> rbuf_offset = interface -> rbuf_offset + offset;
495
hdr.bh_caplen -= offset;
497
/* If there's not enough room to stash the packet data,
498
we have to skip it (this shouldn't happen in real
500
if (hdr.bh_caplen > len) {
501
interface -> rbuf_offset =
502
BPF_WORDALIGN (interface -> rbuf_offset +
507
/* Copy out the data in the packet... */
508
memcpy(buf, interface->rbuf + interface->rbuf_offset, paylen);
509
interface -> rbuf_offset =
510
BPF_WORDALIGN (interface -> rbuf_offset +
517
int can_unicast_without_arp (ip)
518
struct interface_info *ip;
523
int can_receive_unicast_unconfigured (ip)
524
struct interface_info *ip;
529
int supports_multiple_interfaces (ip)
530
struct interface_info *ip;
535
void maybe_setup_fallback ()
538
struct interface_info *fbi = (struct interface_info *)0;
539
if (setup_fallback (&fbi, MDL)) {
540
if_register_fallback (fbi);
541
status = omapi_register_io_object ((omapi_object_t *)fbi,
543
fallback_discard, 0, 0);
544
if (status != ISC_R_SUCCESS)
545
log_fatal ("Can't register I/O handle for %s: %s",
546
fbi -> name, isc_result_totext (status));
547
interface_dereference (&fbi, MDL);
552
get_hw_addr(const char *name, struct hardware *hw) {
555
struct sockaddr_dl *sa;
557
if (getifaddrs(&ifa) != 0) {
558
log_fatal("Error getting interface information; %m");
562
* Loop through our interfaces finding a match.
565
for (p=ifa; (p != NULL) && (sa == NULL); p = p->ifa_next) {
566
if ((p->ifa_addr->sa_family == AF_LINK) &&
567
!strcmp(p->ifa_name, name)) {
568
sa = (struct sockaddr_dl *)p->ifa_addr;
572
log_fatal("No interface called '%s'", name);
576
* Pull out the appropriate information.
578
switch (sa->sdl_type) {
580
hw->hlen = sa->sdl_alen + 1;
581
hw->hbuf[0] = HTYPE_ETHER;
582
memcpy(&hw->hbuf[1], LLADDR(sa), sa->sdl_alen);
585
case IFT_ISO88024: /* "token ring" */
588
hw->hlen = sa->sdl_alen + 1;
589
hw->hbuf[0] = HTYPE_IEEE802;
590
memcpy(&hw->hbuf[1], LLADDR(sa), sa->sdl_alen);
594
hw->hlen = sa->sdl_alen + 1;
595
hw->hbuf[0] = HTYPE_FDDI;
596
memcpy(&hw->hbuf[1], LLADDR(sa), sa->sdl_alen);
598
#endif /* IFT_FDDI */
600
log_fatal("Unsupported device type %d for \"%s\"",
added
removed
common/bpf.c
