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/*
* IS-IS Rout(e)ing protocol - isis_bpf.c
*
* Copyright (C) 2001,2002 Sampo Saaristo
* Tampere University of Technology
* Institute of Communications Engineering
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public Licenseas published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* 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; see the file COPYING; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <zebra.h>
#if ISIS_METHOD == ISIS_METHOD_BPF
#include <net/if.h>
#include <netinet/if_ether.h>
#include <sys/time.h>
#include <sys/ioctl.h>
#include <net/bpf.h>
#include "log.h"
#include "network.h"
#include "stream.h"
#include "if.h"
#include "lib_errors.h"
#include "isisd/dict.h"
#include "isisd/isis_constants.h"
#include "isisd/isis_common.h"
#include "isisd/isis_circuit.h"
#include "isisd/isis_flags.h"
#include "isisd/isisd.h"
#include "isisd/isis_constants.h"
#include "isisd/isis_circuit.h"
#include "isisd/isis_network.h"
#include "isisd/isis_pdu.h"
#include "privs.h"
struct bpf_insn llcfilter[] = {
BPF_STMT(BPF_LD + BPF_B + BPF_ABS,
ETHER_HDR_LEN), /* check first byte */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ISO_SAP, 0, 5),
BPF_STMT(BPF_LD + BPF_B + BPF_ABS, ETHER_HDR_LEN + 1),
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ISO_SAP, 0,
3), /* check second byte */
BPF_STMT(BPF_LD + BPF_B + BPF_ABS, ETHER_HDR_LEN + 2),
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x03, 0, 1), /* check third byte */
BPF_STMT(BPF_RET + BPF_K, (unsigned int)-1),
BPF_STMT(BPF_RET + BPF_K, 0)};
unsigned int readblen = 0;
uint8_t *readbuff = NULL;
/*
* Table 9 - Architectural constants for use with ISO 8802 subnetworks
* ISO 10589 - 8.4.8
*/
uint8_t ALL_L1_ISS[6] = {0x01, 0x80, 0xC2, 0x00, 0x00, 0x14};
uint8_t ALL_L2_ISS[6] = {0x01, 0x80, 0xC2, 0x00, 0x00, 0x15};
uint8_t ALL_ISS[6] = {0x09, 0x00, 0x2B, 0x00, 0x00, 0x05};
uint8_t ALL_ESS[6] = {0x09, 0x00, 0x2B, 0x00, 0x00, 0x04};
static char sock_buff[8192];
static int open_bpf_dev(struct isis_circuit *circuit)
{
int i = 0, fd;
char bpfdev[128];
struct ifreq ifr;
unsigned int blen, immediate;
#ifdef BIOCSSEESENT
unsigned int seesent;
#endif
struct timeval timeout;
struct bpf_program bpf_prog;
do {
(void)snprintf(bpfdev, sizeof(bpfdev), "/dev/bpf%d", i++);
fd = open(bpfdev, O_RDWR);
} while (fd < 0 && errno == EBUSY);
if (fd < 0) {
zlog_warn("open_bpf_dev(): failed to create bpf socket: %s",
safe_strerror(errno));
return ISIS_WARNING;
}
zlog_debug("Opened BPF device %s", bpfdev);
memcpy(ifr.ifr_name, circuit->interface->name, sizeof(ifr.ifr_name));
if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) < 0) {
zlog_warn("open_bpf_dev(): failed to bind to interface: %s",
safe_strerror(errno));
return ISIS_WARNING;
}
if (ioctl(fd, BIOCGBLEN, (caddr_t)&blen) < 0) {
zlog_warn("failed to get BPF buffer len");
blen = circuit->interface->mtu;
}
readblen = blen;
if (readbuff == NULL)
readbuff = malloc(blen);
zlog_debug("BPF buffer len = %u", blen);
/* BPF(4): reads return immediately upon packet reception.
* Otherwise, a read will block until either the kernel
* buffer becomes full or a timeout occurs.
*/
immediate = 1;
if (ioctl(fd, BIOCIMMEDIATE, (caddr_t)&immediate) < 0) {
zlog_warn("failed to set BPF dev to immediate mode");
}
#ifdef BIOCSSEESENT
/*
* We want to see only incoming packets
*/
seesent = 0;
if (ioctl(fd, BIOCSSEESENT, (caddr_t)&seesent) < 0) {
zlog_warn("failed to set BPF dev to incoming only mode");
}
#endif
/*
* ...but all of them
*/
if (ioctl(fd, BIOCPROMISC) < 0) {
zlog_warn("failed to set BPF dev to promiscuous mode");
}
/*
* If the buffer length is smaller than our mtu, lets try to increase it
*/
if (blen < circuit->interface->mtu) {
if (ioctl(fd, BIOCSBLEN, &circuit->interface->mtu) < 0) {
zlog_warn("failed to set BPF buffer len (%u to %u)",
blen, circuit->interface->mtu);
}
}
/*
* Set a timeout parameter - hope this helps select()
*/
timeout.tv_sec = 600;
timeout.tv_usec = 0;
if (ioctl(fd, BIOCSRTIMEOUT, (caddr_t)&timeout) < 0) {
zlog_warn("failed to set BPF device timeout");
}
/*
* And set the filter
*/
memset(&bpf_prog, 0, sizeof(struct bpf_program));
bpf_prog.bf_len = 8;
bpf_prog.bf_insns = &(llcfilter[0]);
if (ioctl(fd, BIOCSETF, (caddr_t)&bpf_prog) < 0) {
zlog_warn("open_bpf_dev(): failed to install filter: %s",
safe_strerror(errno));
return ISIS_WARNING;
}
assert(fd > 0);
circuit->fd = fd;
return ISIS_OK;
}
/*
* Create the socket and set the tx/rx funcs
*/
int isis_sock_init(struct isis_circuit *circuit)
{
int retval = ISIS_OK;
frr_elevate_privs(&isisd_privs) {
retval = open_bpf_dev(circuit);
if (retval != ISIS_OK) {
zlog_warn("%s: could not initialize the socket",
__func__);
break;
}
if (if_is_broadcast(circuit->interface)) {
circuit->tx = isis_send_pdu_bcast;
circuit->rx = isis_recv_pdu_bcast;
} else {
zlog_warn("isis_sock_init(): unknown circuit type");
retval = ISIS_WARNING;
break;
}
}
return retval;
}
int isis_recv_pdu_bcast(struct isis_circuit *circuit, uint8_t *ssnpa)
{
int bytesread = 0, bytestoread, offset, one = 1;
uint8_t *buff_ptr;
struct bpf_hdr *bpf_hdr;
assert(circuit->fd > 0);
if (ioctl(circuit->fd, FIONREAD, (caddr_t)&bytestoread) < 0) {
zlog_warn("ioctl() FIONREAD failed: %s", safe_strerror(errno));
}
if (bytestoread) {
bytesread = read(circuit->fd, readbuff, readblen);
}
if (bytesread < 0) {
zlog_warn("isis_recv_pdu_bcast(): read() failed: %s",
safe_strerror(errno));
return ISIS_WARNING;
}
if (bytesread == 0)
return ISIS_WARNING;
buff_ptr = readbuff;
while (buff_ptr < readbuff + bytesread) {
bpf_hdr = (struct bpf_hdr *) buff_ptr;
assert(bpf_hdr->bh_caplen == bpf_hdr->bh_datalen);
offset = bpf_hdr->bh_hdrlen + LLC_LEN + ETHER_HDR_LEN;
/* then we lose the BPF, LLC and ethernet headers */
stream_write(circuit->rcv_stream, buff_ptr + offset,
bpf_hdr->bh_caplen - LLC_LEN - ETHER_HDR_LEN);
stream_set_getp(circuit->rcv_stream, 0);
memcpy(ssnpa, buff_ptr + bpf_hdr->bh_hdrlen + ETHER_ADDR_LEN,
ETHER_ADDR_LEN);
isis_handle_pdu(circuit, ssnpa);
stream_reset(circuit->rcv_stream);
buff_ptr += BPF_WORDALIGN(bpf_hdr->bh_hdrlen +
bpf_hdr->bh_datalen);
}
if (ioctl(circuit->fd, BIOCFLUSH, &one) < 0)
zlog_warn("Flushing failed: %s", safe_strerror(errno));
return ISIS_OK;
}
int isis_send_pdu_bcast(struct isis_circuit *circuit, int level)
{
struct ether_header *eth;
ssize_t written;
size_t buflen;
buflen = stream_get_endp(circuit->snd_stream) + LLC_LEN + ETHER_HDR_LEN;
if (buflen > sizeof(sock_buff)) {
zlog_warn(
"isis_send_pdu_bcast: sock_buff size %zu is less than "
"output pdu size %zu on circuit %s",
sizeof(sock_buff), buflen, circuit->interface->name);
return ISIS_WARNING;
}
stream_set_getp(circuit->snd_stream, 0);
/*
* First the eth header
*/
eth = (struct ether_header *)sock_buff;
if (level == 1)
memcpy(eth->ether_dhost, ALL_L1_ISS, ETH_ALEN);
else
memcpy(eth->ether_dhost, ALL_L2_ISS, ETH_ALEN);
memcpy(eth->ether_shost, circuit->u.bc.snpa, ETH_ALEN);
size_t frame_size = stream_get_endp(circuit->snd_stream) + LLC_LEN;
eth->ether_type = htons(isis_ethertype(frame_size));
/*
* Then the LLC
*/
sock_buff[ETHER_HDR_LEN] = ISO_SAP;
sock_buff[ETHER_HDR_LEN + 1] = ISO_SAP;
sock_buff[ETHER_HDR_LEN + 2] = 0x03;
/* then we copy the data */
memcpy(sock_buff + (LLC_LEN + ETHER_HDR_LEN), circuit->snd_stream->data,
stream_get_endp(circuit->snd_stream));
/* now we can send this */
written = write(circuit->fd, sock_buff, buflen);
if (written < 0) {
zlog_warn("IS-IS bpf: could not transmit packet on %s: %s",
circuit->interface->name, safe_strerror(errno));
if (ERRNO_IO_RETRY(errno))
return ISIS_WARNING;
return ISIS_ERROR;
}
return ISIS_OK;
}
#endif /* ISIS_METHOD == ISIS_METHOD_BPF */
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