Gb: add a second NS implementation
Reimplement NS with FSM.
Change-Id: I3525beef205588dfab9d3880a34115f1a2676e48
diff --git a/src/gb/gprs_ns2_frgre.c b/src/gb/gprs_ns2_frgre.c
new file mode 100644
index 0000000..2b19157
--- /dev/null
+++ b/src/gb/gprs_ns2_frgre.c
@@ -0,0 +1,596 @@
+/*! \file gprs_ns2_frgre.c
+ * NS-over-FR-over-GRE implementation.
+ * GPRS Networks Service (NS) messages on the Gb interface.
+ * 3GPP TS 08.16 version 8.0.1 Release 1999 / ETSI TS 101 299 V8.0.1 (2002-05)
+ * as well as its successor 3GPP TS 48.016 */
+
+/* (C) 2009-2010,2014,2017 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2020 sysmocom - s.f.m.c. GmbH
+ * Author: Alexander Couzens <lynxis@fe80.eu>
+ *
+ * All Rights Reserved
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as 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. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <netinet/ip6.h>
+#include <arpa/inet.h>
+
+#include <osmocom/core/byteswap.h>
+#include <osmocom/core/logging.h>
+#include <osmocom/core/msgb.h>
+#include <osmocom/core/select.h>
+#include <osmocom/core/socket.h>
+#include <osmocom/core/talloc.h>
+#include <osmocom/gprs/gprs_ns2.h>
+
+#include "gprs_ns2_internal.h"
+
+#define GRE_PTYPE_FR 0x6559
+#define GRE_PTYPE_IPv4 0x0800
+#define GRE_PTYPE_IPv6 0x86dd
+#define GRE_PTYPE_KAR 0x0000 /* keepalive response */
+
+#ifndef IPPROTO_GRE
+# define IPPROTO_GRE 47
+#endif
+
+struct gre_hdr {
+ uint16_t flags;
+ uint16_t ptype;
+} __attribute__ ((packed));
+
+#if defined(__FreeBSD__) || defined(__APPLE__) || defined(__CYGWIN__)
+/**
+ * On BSD the IPv4 struct is called struct ip and instead of iXX
+ * the members are called ip_XX. One could change this code to use
+ * struct ip but that would require to define _BSD_SOURCE and that
+ * might have other complications. Instead make sure struct iphdr
+ * is present on FreeBSD. The below is taken from GLIBC.
+ *
+ * The GNU C Library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ */
+struct iphdr
+ {
+#if BYTE_ORDER == LITTLE_ENDIAN
+ unsigned int ihl:4;
+ unsigned int version:4;
+#elif BYTE_ORDER == BIG_ENDIAN
+ unsigned int version:4;
+ unsigned int ihl:4;
+#endif
+ u_int8_t tos;
+ u_int16_t tot_len;
+ u_int16_t id;
+ u_int16_t frag_off;
+ u_int8_t ttl;
+ u_int8_t protocol;
+ u_int16_t check;
+ u_int32_t saddr;
+ u_int32_t daddr;
+ /*The options start here. */
+ };
+#endif
+
+
+static void free_bind(struct gprs_ns2_vc_bind *bind);
+static inline int frgre_sendmsg(struct gprs_ns2_vc_bind *bind,
+ struct msgb *msg,
+ struct osmo_sockaddr *dest);
+
+struct gprs_ns2_vc_driver vc_driver_frgre = {
+ .name = "GB frame relay over GRE",
+ .free_bind = free_bind,
+};
+
+struct priv_bind {
+ struct osmo_fd fd;
+ struct osmo_sockaddr addr;
+ uint16_t dlci;
+ int dscp;
+};
+
+struct priv_vc {
+ struct osmo_sockaddr remote;
+ uint16_t dlci;
+};
+
+static void free_vc(struct gprs_ns2_vc *nsvc)
+{
+ OSMO_ASSERT(nsvc);
+
+ if (!nsvc->priv)
+ return;
+
+ talloc_free(nsvc->priv);
+ nsvc->priv = NULL;
+}
+
+
+/*! clean up all private driver state. Should be only called by gprs_ns2_free_bind() */
+static void free_bind(struct gprs_ns2_vc_bind *bind)
+{
+ struct priv_bind *priv;
+
+ if (!bind)
+ return;
+
+ priv = bind->priv;
+
+ OSMO_ASSERT(llist_empty(&bind->nsvc));
+
+ osmo_fd_close(&priv->fd);
+ talloc_free(priv);
+}
+
+static struct priv_vc *frgre_alloc_vc(struct gprs_ns2_vc_bind *bind,
+ struct gprs_ns2_vc *nsvc,
+ struct osmo_sockaddr *remote,
+ uint16_t dlci)
+{
+ struct priv_vc *priv = talloc_zero(bind, struct priv_vc);
+ if (!priv)
+ return NULL;
+
+ nsvc->priv = priv;
+ priv->remote = *remote;
+ priv->dlci = dlci;
+
+ return priv;
+}
+
+static int handle_rx_gre_ipv6(struct osmo_fd *bfd, struct msgb *msg,
+ struct ip6_hdr *ip6hdr, struct gre_hdr *greh)
+{
+ /* RFC 7676 IPv6 Support for Generic Routing Encapsulation (GRE) */
+ struct gprs_ns2_vc_bind *bind = bfd->data;
+ struct priv_bind *priv = bind->priv;
+ int gre_payload_len;
+ struct ip6_hdr *inner_ip6h;
+ struct gre_hdr *inner_greh;
+ struct sockaddr_in6 daddr;
+ struct in6_addr ia6;
+
+ gre_payload_len = msg->len - (sizeof(*ip6hdr) + sizeof(*greh));
+
+ inner_ip6h = (struct ip6_hdr *) ((uint8_t *)greh + sizeof(*greh));
+
+ if (gre_payload_len < sizeof(*ip6hdr) + sizeof(*inner_greh)) {
+ LOGP(DLNS, LOGL_ERROR, "GRE keepalive too short\n");
+ return -EIO;
+ }
+
+ if (!memcmp(&inner_ip6h->ip6_src, &ip6hdr->ip6_src, sizeof(struct in6_addr)) ||
+ !memcmp(&inner_ip6h->ip6_dst, &ip6hdr->ip6_dst, sizeof(struct in6_addr))) {
+ LOGP(DLNS, LOGL_ERROR,
+ "GRE keepalive with wrong tunnel addresses\n");
+ return -EIO;
+ }
+
+ /* Are IPv6 extensions header are allowed in the *inner*? In the outer they are */
+ if (inner_ip6h->ip6_ctlun.ip6_un1.ip6_un1_nxt != IPPROTO_GRE) {
+ LOGP(DLNS, LOGL_ERROR, "GRE keepalive with wrong protocol\n");
+ return -EIO;
+ }
+
+ inner_greh = (struct gre_hdr *) ((uint8_t *)inner_ip6h + sizeof(struct ip6_hdr));
+ if (inner_greh->ptype != osmo_htons(GRE_PTYPE_KAR)) {
+ LOGP(DLNS, LOGL_ERROR, "GRE keepalive inner GRE type != 0\n");
+ return -EIO;
+ }
+
+ /* Actually send the response back */
+
+ daddr.sin6_family = AF_INET6;
+ daddr.sin6_addr = inner_ip6h->ip6_dst;
+ daddr.sin6_port = IPPROTO_GRE;
+
+ ia6 = ip6hdr->ip6_src;
+ char ip6str[INET6_ADDRSTRLEN] = {};
+ inet_ntop(AF_INET6, &ia6, ip6str, INET6_ADDRSTRLEN);
+ LOGP(DLNS, LOGL_DEBUG, "GRE keepalive from %s, responding\n", ip6str);
+
+ /* why does it reduce the gre_payload_len by the ipv6 header?
+ * make it similiar to ipv4 even this seems to be wrong */
+ return sendto(priv->fd.fd, inner_greh,
+ gre_payload_len - sizeof(*inner_ip6h), 0,
+ (struct sockaddr *)&daddr, sizeof(daddr));
+}
+
+/* IPv4 messages inside the GRE tunnel might be GRE keepalives */
+static int handle_rx_gre_ipv4(struct osmo_fd *bfd, struct msgb *msg,
+ struct iphdr *iph, struct gre_hdr *greh)
+{
+ struct gprs_ns2_vc_bind *bind = bfd->data;
+ struct priv_bind *priv = bind->priv;
+ int gre_payload_len;
+ struct iphdr *inner_iph;
+ struct gre_hdr *inner_greh;
+ struct sockaddr_in daddr;
+ struct in_addr ia;
+
+ gre_payload_len = msg->len - (iph->ihl*4 + sizeof(*greh));
+
+ inner_iph = (struct iphdr *) ((uint8_t *)greh + sizeof(*greh));
+
+ if (gre_payload_len < inner_iph->ihl*4 + sizeof(*inner_greh)) {
+ LOGP(DLNS, LOGL_ERROR, "GRE keepalive too short\n");
+ return -EIO;
+ }
+
+ if (inner_iph->saddr != iph->daddr ||
+ inner_iph->daddr != iph->saddr) {
+ LOGP(DLNS, LOGL_ERROR,
+ "GRE keepalive with wrong tunnel addresses\n");
+ return -EIO;
+ }
+
+ if (inner_iph->protocol != IPPROTO_GRE) {
+ LOGP(DLNS, LOGL_ERROR, "GRE keepalive with wrong protocol\n");
+ return -EIO;
+ }
+
+ inner_greh = (struct gre_hdr *) ((uint8_t *)inner_iph + iph->ihl*4);
+ if (inner_greh->ptype != osmo_htons(GRE_PTYPE_KAR)) {
+ LOGP(DLNS, LOGL_ERROR, "GRE keepalive inner GRE type != 0\n");
+ return -EIO;
+ }
+
+ /* Actually send the response back */
+
+ daddr.sin_family = AF_INET;
+ daddr.sin_addr.s_addr = inner_iph->daddr;
+ daddr.sin_port = IPPROTO_GRE;
+
+ ia.s_addr = iph->saddr;
+ LOGP(DLNS, LOGL_DEBUG, "GRE keepalive from %s, responding\n",
+ inet_ntoa(ia));
+
+ /* why does it reduce the gre_payload_len by the ipv4 header? */
+ return sendto(priv->fd.fd, inner_greh,
+ gre_payload_len - inner_iph->ihl*4, 0,
+ (struct sockaddr *)&daddr, sizeof(daddr));
+}
+
+static struct msgb *read_nsfrgre_msg(struct osmo_fd *bfd, int *error,
+ struct osmo_sockaddr *saddr, uint16_t *dlci)
+{
+ struct msgb *msg = msgb_alloc(NS_ALLOC_SIZE, "Gb/NS/FR/GRE Rx");
+ int ret = 0;
+ socklen_t saddr_len = sizeof(*saddr);
+ struct iphdr *iph = NULL;
+ struct ip6_hdr *ip6h = NULL;
+ size_t ip46hdr;
+ struct gre_hdr *greh;
+ uint8_t *frh;
+
+ if (!msg) {
+ *error = -ENOMEM;
+ return NULL;
+ }
+
+ ret = recvfrom(bfd->fd, msg->data, NS_ALLOC_SIZE, 0,
+ &saddr->u.sa, &saddr_len);
+ if (ret < 0) {
+ LOGP(DLNS, LOGL_ERROR, "recv error %s during NS-FR-GRE recv\n",
+ strerror(errno));
+ *error = ret;
+ goto out_err;
+ } else if (ret == 0) {
+ *error = ret;
+ goto out_err;
+ }
+
+ msgb_put(msg, ret);
+
+ /* we've received a raw packet including the IPv4 or IPv6 header */
+ switch (saddr->u.sa.sa_family) {
+ case AF_INET:
+ ip46hdr = sizeof(struct iphdr);
+ break;
+ case AF_INET6:
+ ip46hdr = sizeof(struct ip6_hdr);
+ default:
+ *error = -EIO;
+ goto out_err;
+ break;
+ }
+
+ /* TODO: add support for the extension headers */
+ if (msg->len < ip46hdr + sizeof(*greh) + 2) {
+ LOGP(DLNS, LOGL_ERROR, "Short IP packet: %u bytes\n", msg->len);
+ *error = -EIO;
+ goto out_err;
+ }
+
+ switch (saddr->u.sa.sa_family) {
+ case AF_INET:
+ iph = (struct iphdr *) msg->data;
+ if (msg->len < (iph->ihl*4 + sizeof(*greh) + 2)) {
+ LOGP(DLNS, LOGL_ERROR, "Short IP packet: %u bytes\n", msg->len);
+ *error = -EIO;
+ goto out_err;
+ }
+ break;
+ case AF_INET6:
+ ip6h = (struct ip6_hdr *) msg->data;
+ break;
+ }
+
+ greh = (struct gre_hdr *) (msg->data + iph->ihl*4);
+ if (greh->flags) {
+ LOGP(DLNS, LOGL_NOTICE, "Unknown GRE flags 0x%04x\n",
+ osmo_ntohs(greh->flags));
+ }
+
+ switch (osmo_ntohs(greh->ptype)) {
+ case GRE_PTYPE_IPv4:
+ /* IPv4 messages might be GRE keepalives */
+ *error = handle_rx_gre_ipv4(bfd, msg, iph, greh);
+ goto out_err;
+ break;
+ case GRE_PTYPE_IPv6:
+ *error = handle_rx_gre_ipv6(bfd, msg, ip6h, greh);
+ goto out_err;
+ break;
+ case GRE_PTYPE_FR:
+ /* continue as usual */
+ break;
+ default:
+ LOGP(DLNS, LOGL_NOTICE, "Unknown GRE protocol 0x%04x != FR\n",
+ osmo_ntohs(greh->ptype));
+ *error = -EIO;
+ goto out_err;
+ break;
+ }
+
+ if (msg->len < sizeof(*greh) + 2) {
+ LOGP(DLNS, LOGL_ERROR, "Short FR header: %u bytes\n", msg->len);
+ *error = -EIO;
+ goto out_err;
+ }
+
+ frh = (uint8_t *)greh + sizeof(*greh);
+ if (frh[0] & 0x01) {
+ LOGP(DLNS, LOGL_NOTICE, "Unsupported single-byte FR address\n");
+ *error = -EIO;
+ goto out_err;
+ }
+ *dlci = ((frh[0] & 0xfc) << 2);
+ if ((frh[1] & 0x0f) != 0x01) {
+ LOGP(DLNS, LOGL_NOTICE, "Unknown second FR octet 0x%02x\n",
+ frh[1]);
+ *error = -EIO;
+ goto out_err;
+ }
+ *dlci |= (frh[1] >> 4);
+
+ msg->l2h = frh+2;
+
+ return msg;
+
+out_err:
+ msgb_free(msg);
+ return NULL;
+}
+
+static int gprs_ns2_find_vc_by_dlci(struct gprs_ns2_vc_bind *bind,
+ uint16_t dlci,
+ struct gprs_ns2_vc **result)
+{
+ struct gprs_ns2_vc *nsvc;
+ struct priv_vc *vcpriv;
+
+ if (!result)
+ return -EINVAL;
+
+ llist_for_each_entry(nsvc, &bind->nsvc, blist) {
+ vcpriv = nsvc->priv;
+ if (vcpriv->dlci != dlci) {
+ *result = nsvc;
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
+static int handle_nsfrgre_read(struct osmo_fd *bfd)
+{
+ int rc;
+ struct osmo_sockaddr saddr;
+ struct gprs_ns2_vc *nsvc;
+ struct gprs_ns2_vc_bind *bind = bfd->data;
+ struct msgb *msg;
+ struct msgb *reject;
+ uint16_t dlci;
+
+ msg = read_nsfrgre_msg(bfd, &rc, &saddr, &dlci);
+ if (!msg)
+ return rc;
+
+ if (dlci == 0 || dlci == 1023) {
+ LOGP(DLNS, LOGL_INFO, "Received FR on LMI DLCI %u - ignoring\n",
+ dlci);
+ rc = 0;
+ goto out;
+ }
+
+ rc = gprs_ns2_find_vc_by_dlci(bind, dlci, &nsvc);
+ if (rc) {
+ /* VC not found */
+ rc = ns2_create_vc(bind, msg, "newconnection", &reject, &nsvc);
+ switch (rc) {
+ case GPRS_NS2_CS_FOUND:
+ rc = ns2_recv_vc(bind->nsi, nsvc, msg);
+ break;
+ case GPRS_NS2_CS_ERROR:
+ case GPRS_NS2_CS_SKIPPED:
+ rc = 0;
+ break;
+ case GPRS_NS2_CS_REJECTED:
+ /* nsip_sendmsg will free reject */
+ frgre_sendmsg(bind, reject, &saddr);
+ return 0;
+ case GPRS_NS2_CS_CREATED:
+ frgre_alloc_vc(bind, nsvc, &saddr, dlci);
+ gprs_ns2_vc_fsm_start(nsvc);
+ rc = ns2_recv_vc(bind->nsi, nsvc, msg);
+ break;
+ }
+ } else {
+ /* VC found */
+ rc = ns2_recv_vc(bind->nsi, nsvc, msg);
+ }
+out:
+ msgb_free(msg);
+
+ return rc;
+}
+
+static int handle_nsfrgre_write(struct osmo_fd *bfd)
+{
+ /* FIXME: actually send the data here instead of nsip_sendmsg() */
+ return -EIO;
+}
+
+static inline int frgre_sendmsg(struct gprs_ns2_vc_bind *bind,
+ struct msgb *msg,
+ struct osmo_sockaddr *dest)
+{
+ int rc;
+ struct priv_bind *priv = bind->priv;
+
+ rc = sendto(priv->fd.fd, msg->data, msg->len, 0,
+ &dest->u.sa, sizeof(*dest));
+
+ msgb_free(msg);
+
+ return rc;
+}
+
+static int frgre_vc_sendmsg(struct gprs_ns2_vc *nsvc, struct msgb *msg)
+{
+ struct gprs_ns2_vc_bind *bind = nsvc->bind;
+ struct priv_vc *vcpriv = nsvc->priv;
+ struct priv_bind *bindpriv = bind->priv;
+
+ uint16_t dlci = osmo_htons(bindpriv->dlci);
+ uint8_t *frh;
+ struct gre_hdr *greh;
+
+ /* Prepend the FR header */
+ frh = msgb_push(msg, 2);
+ frh[0] = (dlci >> 2) & 0xfc;
+ frh[1] = ((dlci & 0xf)<<4) | 0x01;
+
+ /* Prepend the GRE header */
+ greh = (struct gre_hdr *) msgb_push(msg, sizeof(*greh));
+ greh->flags = 0;
+ greh->ptype = osmo_htons(GRE_PTYPE_FR);
+
+ return frgre_sendmsg(bind, msg, &vcpriv->remote);
+}
+
+static int frgre_fd_cb(struct osmo_fd *bfd, unsigned int what)
+{
+ int rc = 0;
+
+ if (what & OSMO_FD_READ)
+ rc = handle_nsfrgre_read(bfd);
+ if (what & OSMO_FD_WRITE)
+ rc = handle_nsfrgre_write(bfd);
+
+ return rc;
+}
+
+int gprs_ns2_is_frgre_bind(struct gprs_ns2_vc_bind *bind)
+{
+ return (bind->driver == &vc_driver_frgre);
+}
+
+int gprs_ns2_frgre_bind(struct gprs_ns2_inst *nsi,
+ struct osmo_sockaddr *local,
+ int dscp,
+ struct gprs_ns2_vc_bind **result)
+{
+ struct gprs_ns2_vc_bind *bind = talloc_zero(nsi, struct gprs_ns2_vc_bind);
+ struct priv_bind *priv;
+ int rc;
+
+ if (!bind)
+ return -ENOSPC;
+
+ if (local->u.sa.sa_family != AF_INET && local->u.sa.sa_family != AF_INET6) {
+ talloc_free(bind);
+ return -EINVAL;
+ }
+
+ bind->driver = &vc_driver_frgre;
+ bind->send_vc = frgre_vc_sendmsg;
+ bind->free_vc = free_vc;
+ bind->nsi = nsi;
+
+ priv = bind->priv = talloc_zero(bind, struct priv_bind);
+ if (!priv) {
+ talloc_free(bind);
+ return -ENOSPC;
+ }
+ priv->fd.cb = frgre_fd_cb;
+ priv->fd.data = bind;
+ priv->addr = *local;
+ INIT_LLIST_HEAD(&bind->nsvc);
+
+ llist_add(&bind->list, &nsi->binding);
+
+ rc = osmo_sock_init_osa_ofd(&priv->fd, SOCK_RAW, IPPROTO_GRE,
+ local, NULL,
+ OSMO_SOCK_F_BIND);
+ if (rc < 0) {
+ talloc_free(priv);
+ talloc_free(bind);
+ return rc;
+ }
+
+ if (dscp > 0) {
+ priv->dscp = dscp;
+
+ rc = setsockopt(priv->fd.fd, IPPROTO_IP, IP_TOS,
+ &dscp, sizeof(dscp));
+ if (rc < 0)
+ LOGP(DLNS, LOGL_ERROR,
+ "Failed to set the DSCP to %d with ret(%d) errno(%d)\n",
+ dscp, rc, errno);
+ }
+
+ ns2_vty_bind_apply(bind);
+
+ if (result)
+ *result = bind;
+
+ return rc;
+}