1 files changed, 301 insertions, 0 deletions
diff --git a/isisd/isis_bpf.c b/isisd/isis_bpf.c
new file mode 100644
index 0000000..96d6291
--- /dev/null
+++ b/isisd/isis_bpf.c
@@ -0,0 +1,301 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * IS-IS Rout(e)ing protocol - isis_bpf.c
+ *
+ * Copyright (C) 2001,2002    Sampo Saaristo
+ *                            Tampere University of Technology
+ *                            Institute of Communications Engineering
+ */
+
+#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/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
+ */
+
+static const uint8_t ALL_L1_ISS[6] = {0x01, 0x80, 0xC2, 0x00, 0x00, 0x14};
+static const uint8_t ALL_L2_ISS[6] = {0x01, 0x80, 0xC2, 0x00, 0x00, 0x15};
+static char sock_buff[16384];
+
+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(bpf_prog));
+	bpf_prog.bf_len = 8;
+	bpf_prog.bf_insns = &(llcfilter[0]);
+	if (ioctl(fd, BIOCSETF, (caddr_t)&bpf_prog) < 0) {
+		zlog_warn("%s: failed to install filter: %s", __func__,
+			  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_with_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("%s: unknown circuit type", __func__);
+			retval = ISIS_WARNING;
+			break;
+		}
+	}
+
+	return retval;
+}
+
+int isis_recv_pdu_bcast(struct isis_circuit *circuit, uint8_t *ssnpa)
+{
+	int bytesread = 0, bytestoread = 0, 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("%s: read() failed: %s", __func__,
+			  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(
+			"%s: sock_buff size %zu is less than output pdu size %zu on circuit %s",
+			__func__, 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 */