diff options
Diffstat (limited to 'openbsc/src/gprs/gprs_ns_frgre.c')
| -rw-r--r-- | openbsc/src/gprs/gprs_ns_frgre.c | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/openbsc/src/gprs/gprs_ns_frgre.c b/openbsc/src/gprs/gprs_ns_frgre.c new file mode 100644 index 00000000..d58c1d9d --- /dev/null +++ b/openbsc/src/gprs/gprs_ns_frgre.c @@ -0,0 +1,222 @@ +/* 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) */ + +/* NS-over-FR-over-GRE implementation */ + +/* (C) 2009-2010 by Harald Welte <laforge@gnumonks.org> + * + * All Rights Reserved + * + * 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, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + * + */ + +#include <errno.h> +#include <string.h> +#include <unistd.h> + +#include <sys/socket.h> +#include <netinet/in.h> +#include <arpa/inet.h> + +#include <osmocore/select.h> +#include <osmocore/msgb.h> +#include <osmocore/talloc.h> + +#include <openbsc/socket.h> +#include <openbsc/debug.h> +#include <openbsc/gprs_ns.h> + +#define GRE_PTYPE_FR 0x6559 + +struct gre_hdr { + uint16_t flags; + uint16_t ptype; +} __attribute__ ((packed)); + +static struct msgb *read_nsfrgre_msg(struct bsc_fd *bfd, int *error, + struct sockaddr_in *saddr) +{ + struct msgb *msg = msgb_alloc(NS_ALLOC_SIZE, "Gb/NS/FR/GRE Rx"); + int ret = 0; + socklen_t saddr_len = sizeof(*saddr); + struct gre_hdr *greh; + uint8_t *frh; + uint32_t dlci; + + if (!msg) { + *error = -ENOMEM; + return NULL; + } + + ret = recvfrom(bfd->fd, msg->data, NS_ALLOC_SIZE, 0, + (struct sockaddr *)saddr, &saddr_len); + if (ret < 0) { + LOGP(DNS, LOGL_ERROR, "recv error %s during NS-FR-GRE recv\n", + strerror(errno)); + *error = ret; + return NULL; + } else if (ret == 0) { + msgb_free(msg); + *error = ret; + return NULL; + } + + msgb_put(msg, ret); + + if (msg->len < sizeof(*greh)) { + LOGP(DNS, LOGL_ERROR, "Short GRE packet: %u bytes\n", msg->len); + *error = -EIO; + goto out_err; + } + + greh = (struct gre_hdr *) msg->data; + if (greh->flags) { + LOGP(DNS, LOGL_NOTICE, "Unknown GRE flags 0x%04x\n", + ntohs(greh->flags)); + } + if (greh->ptype != htons(GRE_PTYPE_FR)) { + LOGP(DNS, LOGL_NOTICE, "Unknown GRE protocol 0x%04x != FR\n", + ntohs(greh->ptype)); + *error = -EIO; + goto out_err; + } + + if (msg->len < sizeof(*greh) + 2) { + LOGP(DNS, LOGL_ERROR, "Short FR header: %u bytes\n", msg->len); + *error = -EIO; + goto out_err; + } + + frh = msg->data + sizeof(*greh); + if (frh[0] & 0x01) { + LOGP(DNS, LOGL_NOTICE, "Unsupported single-byte FR address\n"); + *error = -EIO; + goto out_err; + } + dlci = (frh[0] & 0xfc << 2); + if ((frh[1] & 0x0f) != 0x01) { + LOGP(DNS, LOGL_NOTICE, "Unknown second FR octet 0x%02x\n", + frh[1]); + *error = -EIO; + goto out_err; + } + dlci |= frh[1] >> 4; + if (dlci > 0xffff) { + LOGP(DNS, LOGL_ERROR, "We don't support DLCI > 65535 (%u)\n", + dlci); + *error = -EINVAL; + goto out_err; + } + + msg->l2h = msg->data + sizeof(*greh) + 2; + + /* Store DLCI in NETWORK BYTEORDER in sockaddr port member */ + saddr->sin_port = htons(dlci & 0xffff); + + return msg; + +out_err: + msgb_free(msg); + return NULL; +} + +int gprs_ns_rcvmsg(struct gprs_ns_inst *nsi, struct msgb *msg, + struct sockaddr_in *saddr, enum gprs_ns_ll ll); + +static int handle_nsfrgre_read(struct bsc_fd *bfd) +{ + int error; + struct sockaddr_in saddr; + struct gprs_ns_inst *nsi = bfd->data; + struct msgb *msg = read_nsfrgre_msg(bfd, &error, &saddr); + + if (!msg) + return error; + + error = gprs_ns_rcvmsg(nsi, msg, &saddr, GPRS_NS_LL_FR_GRE); + + msgb_free(msg); + + return error; +} + +static int handle_nsfrgre_write(struct bsc_fd *bfd) +{ + /* FIXME: actually send the data here instead of nsip_sendmsg() */ + return -EIO; +} + +int gprs_ns_frgre_sendmsg(struct gprs_nsvc *nsvc, struct msgb *msg) +{ + int rc; + struct gprs_ns_inst *nsi = nsvc->nsi; + struct sockaddr_in daddr; + uint16_t dlci = ntohs(nsvc->frgre.bts_addr.sin_port); + uint8_t *frh; + struct gre_hdr *greh; + + /* Build socket address for the packet destionation */ + daddr.sin_addr = nsvc->frgre.bts_addr.sin_addr; + daddr.sin_port = IPPROTO_GRE; + + /* Prepend the FR header */ + frh = msgb_push(msg, sizeof(frh)); + frh[0] = (dlci >> 2) & 0xfc; + frh[1] = (dlci & 0xf0) | 0x01; + + /* Prepend the GRE header */ + greh = (struct gre_hdr *) msgb_push(msg, sizeof(*greh)); + greh->flags = 0; + greh->ptype = GRE_PTYPE_FR; + + rc = sendto(nsi->frgre.fd.fd, msg->data, msg->len, 0, + (struct sockaddr *)&daddr, sizeof(daddr)); + + talloc_free(msg); + + return rc; +} + +static int nsfrgre_fd_cb(struct bsc_fd *bfd, unsigned int what) +{ + int rc = 0; + + if (what & BSC_FD_READ) + rc = handle_nsfrgre_read(bfd); + if (what & BSC_FD_WRITE) + rc = handle_nsfrgre_write(bfd); + + return rc; +} + +int gprs_ns_frgre_listen(struct gprs_ns_inst *nsi, uint32_t ip) +{ + int rc; + + /* Make sure we close any existing socket before changing it */ + if (nsi->frgre.fd.fd) + close(nsi->frgre.fd.fd); + + rc = make_sock(&nsi->frgre.fd, IPPROTO_GRE, ip, 0, nsfrgre_fd_cb); + if (rc < 0) { + LOGP(DNS, LOGL_ERROR, "Error creating GRE socket (%s)\n", + strerror(errno)); + return rc; + } + nsi->frgre.fd.data = nsi; + + return rc; +} |