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-rw-r--r--isisd/isis_pfpacket.c424
1 files changed, 424 insertions, 0 deletions
diff --git a/isisd/isis_pfpacket.c b/isisd/isis_pfpacket.c
new file mode 100644
index 0000000..af69fac
--- /dev/null
+++ b/isisd/isis_pfpacket.c
@@ -0,0 +1,424 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * IS-IS Rout(e)ing protocol - isis_pfpacket.c
+ *
+ * Copyright (C) 2001,2002 Sampo Saaristo
+ * Tampere University of Technology
+ * Institute of Communications Engineering
+ */
+
+#include <zebra.h>
+#if ISIS_METHOD == ISIS_METHOD_PFPACKET
+#include <net/ethernet.h> /* the L2 protocols */
+#include <netpacket/packet.h>
+
+#include <linux/filter.h>
+
+#include "log.h"
+#include "network.h"
+#include "stream.h"
+#include "if.h"
+#include "lib_errors.h"
+#include "vrf.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 "privs.h"
+
+/* tcpdump -i eth0 'isis' -dd */
+static const struct sock_filter isisfilter[] = {
+ /* NB: we're in SOCK_DGRAM, so src/dst mac + length are stripped
+ * off! */
+ /* The following BPF filter accepts IS-IS over LLC and IS-IS over
+ * ethertype 0x00fe.
+ * BPF assembly:
+ * l0: ldh [0]
+ * l1: jeq #0xfefe, l2, l4
+ * l2: ldb [3]
+ * l3: jmp l7
+ * l4: ldh proto
+ * l5: jeq #0x00fe, l6, l9
+ * l6: ldb [0]
+ * l7: jeq #0x83, l8, l9
+ * l8: ret #0x40000
+ * l9: ret #0 */
+ {0x28, 0, 0, 0000000000}, {0x15, 0, 2, 0x0000fefe},
+ {0x30, 0, 0, 0x00000003}, {0x05, 0, 0, 0x00000003},
+ {0x28, 0, 0, 0xfffff000}, {0x15, 0, 3, 0x000000fe},
+ {0x30, 0, 0, 0000000000}, {0x15, 0, 1, 0x00000083},
+ {0x06, 0, 0, 0x00040000}, {0x06, 0, 0, 0000000000},
+};
+
+static const struct sock_fprog bpf = {
+ .len = array_size(isisfilter),
+ .filter = (struct sock_filter *)isisfilter,
+};
+
+/*
+ * 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 const uint8_t ALL_ISS[6] = {0x09, 0x00, 0x2B, 0x00, 0x00, 0x05};
+static const uint8_t ALL_ESS[6] = {0x09, 0x00, 0x2B, 0x00, 0x00, 0x04};
+
+static uint8_t discard_buff[8192];
+
+/*
+ * if level is 0 we are joining p2p multicast
+ * FIXME: and the p2p multicast being ???
+ */
+static int isis_multicast_join(int fd, int registerto, int if_num)
+{
+ struct packet_mreq mreq;
+
+ memset(&mreq, 0, sizeof(mreq));
+ mreq.mr_ifindex = if_num;
+ if (registerto) {
+ mreq.mr_type = PACKET_MR_MULTICAST;
+ mreq.mr_alen = ETH_ALEN;
+ if (registerto == 1)
+ memcpy(&mreq.mr_address, ALL_L1_ISS, ETH_ALEN);
+ else if (registerto == 2)
+ memcpy(&mreq.mr_address, ALL_L2_ISS, ETH_ALEN);
+ else if (registerto == 3)
+ memcpy(&mreq.mr_address, ALL_ISS, ETH_ALEN);
+ else
+ memcpy(&mreq.mr_address, ALL_ESS, ETH_ALEN);
+
+ } else {
+ mreq.mr_type = PACKET_MR_ALLMULTI;
+ }
+#ifdef EXTREME_DEBUG
+ if (IS_DEBUG_EVENTS)
+ zlog_debug(
+ "%s: fd=%d, reg_to=%d, if_num=%d, address = %02x:%02x:%02x:%02x:%02x:%02x",
+ __func__, fd, registerto, if_num, mreq.mr_address[0],
+ mreq.mr_address[1], mreq.mr_address[2],
+ mreq.mr_address[3], mreq.mr_address[4],
+ mreq.mr_address[5]);
+#endif /* EXTREME_DEBUG */
+ if (setsockopt(fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq,
+ sizeof(struct packet_mreq))) {
+ zlog_warn("%s: setsockopt(): %s", __func__,
+ safe_strerror(errno));
+ return ISIS_WARNING;
+ }
+
+ return ISIS_OK;
+}
+
+static int open_packet_socket(struct isis_circuit *circuit)
+{
+ struct sockaddr_ll s_addr;
+ int fd, retval = ISIS_OK;
+ struct vrf *vrf = NULL;
+
+ vrf = circuit->interface->vrf;
+
+ fd = vrf_socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_ALL), vrf->vrf_id,
+ vrf->name);
+
+ if (fd < 0) {
+ zlog_warn("%s: socket() failed %s", __func__,
+ safe_strerror(errno));
+ return ISIS_WARNING;
+ }
+
+ if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &bpf, sizeof(bpf))) {
+ zlog_warn("%s: SO_ATTACH_FILTER failed: %s", __func__,
+ safe_strerror(errno));
+ }
+
+ /*
+ * Bind to the physical interface
+ */
+ memset(&s_addr, 0, sizeof(s_addr));
+ s_addr.sll_family = AF_PACKET;
+ s_addr.sll_protocol = htons(ETH_P_ALL);
+ s_addr.sll_ifindex = circuit->interface->ifindex;
+
+ if (bind(fd, (struct sockaddr *)(&s_addr), sizeof(struct sockaddr_ll))
+ < 0) {
+ zlog_warn("%s: bind() failed: %s", __func__,
+ safe_strerror(errno));
+ close(fd);
+ return ISIS_WARNING;
+ }
+
+ circuit->fd = fd;
+
+ if (if_is_broadcast(circuit->interface)) {
+ /*
+ * Join to multicast groups
+ * according to
+ * 8.4.2 - Broadcast subnetwork IIH PDUs
+ * FIXME: is there a case only one will fail??
+ */
+ /* joining ALL_L1_ISS */
+ retval |= isis_multicast_join(circuit->fd, 1,
+ circuit->interface->ifindex);
+ /* joining ALL_L2_ISS */
+ retval |= isis_multicast_join(circuit->fd, 2,
+ circuit->interface->ifindex);
+ /* joining ALL_ISS (used in RFC 5309 p2p-over-lan as well) */
+ retval |= isis_multicast_join(circuit->fd, 3,
+ circuit->interface->ifindex);
+ } else {
+ retval = isis_multicast_join(circuit->fd, 0,
+ circuit->interface->ifindex);
+ }
+
+ return retval;
+}
+
+/*
+ * 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_packet_socket(circuit);
+
+ if (retval != ISIS_OK) {
+ zlog_warn("%s: could not initialize the socket",
+ __func__);
+ break;
+ }
+
+ /* Assign Rx and Tx callbacks are based on real if type */
+ if (if_is_broadcast(circuit->interface)) {
+ circuit->tx = isis_send_pdu_bcast;
+ circuit->rx = isis_recv_pdu_bcast;
+ } else if (if_is_pointopoint(circuit->interface)) {
+ circuit->tx = isis_send_pdu_p2p;
+ circuit->rx = isis_recv_pdu_p2p;
+ } else {
+ zlog_warn("%s: unknown circuit type", __func__);
+ retval = ISIS_WARNING;
+ break;
+ }
+ }
+
+ return retval;
+}
+
+static inline int llc_check(uint8_t *llc)
+{
+ if (*llc != ISO_SAP || *(llc + 1) != ISO_SAP || *(llc + 2) != 3)
+ return 0;
+
+ return 1;
+}
+
+int isis_recv_pdu_bcast(struct isis_circuit *circuit, uint8_t *ssnpa)
+{
+ int bytesread, addr_len;
+ struct sockaddr_ll s_addr;
+ uint8_t llc[LLC_LEN];
+
+ addr_len = sizeof(s_addr);
+
+ memset(&s_addr, 0, sizeof(s_addr));
+
+ bytesread =
+ recvfrom(circuit->fd, (void *)&llc, LLC_LEN, MSG_PEEK,
+ (struct sockaddr *)&s_addr, (socklen_t *)&addr_len);
+
+ if ((bytesread < 0)
+ || (s_addr.sll_ifindex != (int)circuit->interface->ifindex)) {
+ if (bytesread < 0) {
+ zlog_warn(
+ "%s: ifname %s, fd %d, bytesread %d, recvfrom(): %s",
+ __func__, circuit->interface->name, circuit->fd,
+ bytesread, safe_strerror(errno));
+ }
+ if (s_addr.sll_ifindex != (int)circuit->interface->ifindex) {
+ zlog_warn(
+ "packet is received on multiple interfaces: socket interface %d, circuit interface %d, packet type %u",
+ s_addr.sll_ifindex, circuit->interface->ifindex,
+ s_addr.sll_pkttype);
+ }
+
+ /* get rid of the packet */
+ bytesread = recvfrom(circuit->fd, discard_buff,
+ sizeof(discard_buff), MSG_DONTWAIT,
+ (struct sockaddr *)&s_addr,
+ (socklen_t *)&addr_len);
+
+ if (bytesread < 0)
+ zlog_warn("%s: recvfrom() failed", __func__);
+
+ return ISIS_WARNING;
+ }
+ /*
+ * Filtering by llc field, discard packets sent by this host (other
+ * circuit)
+ */
+ if (!llc_check(llc) || s_addr.sll_pkttype == PACKET_OUTGOING) {
+ /* Read the packet into discard buff */
+ bytesread = recvfrom(circuit->fd, discard_buff,
+ sizeof(discard_buff), MSG_DONTWAIT,
+ (struct sockaddr *)&s_addr,
+ (socklen_t *)&addr_len);
+ if (bytesread < 0)
+ zlog_warn("%s: recvfrom() failed", __func__);
+ return ISIS_WARNING;
+ }
+
+ /* Ensure that we have enough space for a pdu padded to fill the mtu */
+ unsigned int max_size =
+ circuit->interface->mtu > circuit->interface->mtu6
+ ? circuit->interface->mtu
+ : circuit->interface->mtu6;
+ uint8_t temp_buff[max_size];
+ bytesread =
+ recvfrom(circuit->fd, temp_buff, max_size, MSG_DONTWAIT,
+ (struct sockaddr *)&s_addr, (socklen_t *)&addr_len);
+ if (bytesread < 0) {
+ zlog_warn("%s: recvfrom() failed", __func__);
+ return ISIS_WARNING;
+ }
+ /* then we lose the LLC */
+ stream_write(circuit->rcv_stream, temp_buff + LLC_LEN,
+ bytesread - LLC_LEN);
+ memcpy(ssnpa, &s_addr.sll_addr, s_addr.sll_halen);
+
+ return ISIS_OK;
+}
+
+int isis_recv_pdu_p2p(struct isis_circuit *circuit, uint8_t *ssnpa)
+{
+ int bytesread, addr_len;
+ struct sockaddr_ll s_addr;
+
+ memset(&s_addr, 0, sizeof(s_addr));
+ addr_len = sizeof(s_addr);
+
+ /* we can read directly to the stream */
+ (void)stream_recvfrom(
+ circuit->rcv_stream, circuit->fd, circuit->interface->mtu, 0,
+ (struct sockaddr *)&s_addr, (socklen_t *)&addr_len);
+
+ if (s_addr.sll_pkttype == PACKET_OUTGOING) {
+ /* Read the packet into discard buff */
+ bytesread = recvfrom(circuit->fd, discard_buff,
+ sizeof(discard_buff), MSG_DONTWAIT,
+ (struct sockaddr *)&s_addr,
+ (socklen_t *)&addr_len);
+ if (bytesread < 0)
+ zlog_warn("%s: recvfrom() failed", __func__);
+ return ISIS_WARNING;
+ }
+
+ /* If we don't have protocol type 0x00FE which is
+ * ISO over GRE we exit with pain :)
+ */
+ if (ntohs(s_addr.sll_protocol) != 0x00FE) {
+ zlog_warn("%s: protocol mismatch(): %X", __func__,
+ ntohs(s_addr.sll_protocol));
+ return ISIS_WARNING;
+ }
+
+ memcpy(ssnpa, &s_addr.sll_addr, s_addr.sll_halen);
+
+ return ISIS_OK;
+}
+
+int isis_send_pdu_bcast(struct isis_circuit *circuit, int level)
+{
+ struct msghdr msg;
+ struct iovec iov[2];
+ char temp_buff[LLC_LEN];
+
+ /* we need to do the LLC in here because of P2P circuits, which will
+ * not need it
+ */
+ struct sockaddr_ll sa;
+
+ stream_set_getp(circuit->snd_stream, 0);
+ memset(&sa, 0, sizeof(sa));
+ sa.sll_family = AF_PACKET;
+
+ size_t frame_size = stream_get_endp(circuit->snd_stream) + LLC_LEN;
+ sa.sll_protocol = htons(isis_ethertype(frame_size));
+ sa.sll_ifindex = circuit->interface->ifindex;
+ sa.sll_halen = ETH_ALEN;
+ /* RFC5309 section 4.1 recommends ALL_ISS */
+ if (circuit->circ_type == CIRCUIT_T_P2P)
+ memcpy(&sa.sll_addr, ALL_ISS, ETH_ALEN);
+ else if (level == 1)
+ memcpy(&sa.sll_addr, ALL_L1_ISS, ETH_ALEN);
+ else
+ memcpy(&sa.sll_addr, ALL_L2_ISS, ETH_ALEN);
+
+ /* on a broadcast circuit */
+ /* first we put the LLC in */
+ temp_buff[0] = 0xFE;
+ temp_buff[1] = 0xFE;
+ temp_buff[2] = 0x03;
+
+ memset(&msg, 0, sizeof(msg));
+ msg.msg_name = &sa;
+ msg.msg_namelen = sizeof(struct sockaddr_ll);
+ msg.msg_iov = iov;
+ msg.msg_iovlen = 2;
+ iov[0].iov_base = temp_buff;
+ iov[0].iov_len = LLC_LEN;
+ iov[1].iov_base = circuit->snd_stream->data;
+ iov[1].iov_len = stream_get_endp(circuit->snd_stream);
+
+ if (sendmsg(circuit->fd, &msg, 0) < 0) {
+ zlog_warn("IS-IS pfpacket: 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;
+}
+
+int isis_send_pdu_p2p(struct isis_circuit *circuit, int level)
+{
+ struct sockaddr_ll sa;
+ ssize_t rv;
+
+ stream_set_getp(circuit->snd_stream, 0);
+ memset(&sa, 0, sizeof(sa));
+ sa.sll_family = AF_PACKET;
+ sa.sll_ifindex = circuit->interface->ifindex;
+ sa.sll_halen = ETH_ALEN;
+ if (level == 1)
+ memcpy(&sa.sll_addr, ALL_L1_ISS, ETH_ALEN);
+ else
+ memcpy(&sa.sll_addr, ALL_L2_ISS, ETH_ALEN);
+
+
+ /* lets try correcting the protocol */
+ sa.sll_protocol = htons(0x00FE);
+ rv = sendto(circuit->fd, circuit->snd_stream->data,
+ stream_get_endp(circuit->snd_stream), 0,
+ (struct sockaddr *)&sa, sizeof(struct sockaddr_ll));
+ if (rv < 0) {
+ zlog_warn("IS-IS pfpacket: 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_PFPACKET */
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