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osmo-bsc/src/gprs/gprs_sndcp.c

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/* GPRS SNDCP protocol implementation as per 3GPP TS 04.65 */
/* (C) 2010 by Harald Welte <laforge@gnumonks.org>
* (C) 2010 by On-Waves
*
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation; either version 3 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include <errno.h>
#include <stdint.h>
#include <stdbool.h>
#include <osmocom/core/msgb.h>
#include <osmocom/core/linuxlist.h>
#include <osmocom/core/timer.h>
#include <osmocom/core/talloc.h>
#include <osmocom/gprs/gprs_bssgp.h>
#include <openbsc/gsm_data.h>
#include <openbsc/debug.h>
#include <openbsc/gprs_llc.h>
#include <openbsc/sgsn.h>
#include <openbsc/gprs_sndcp.h>
#include <openbsc/gprs_llc_xid.h>
#include <openbsc/gprs_sndcp_xid.h>
#include <openbsc/gprs_sndcp_pcomp.h>
#include <openbsc/gprs_sndcp_dcomp.h>
#include <openbsc/gprs_sndcp_comp.h>
#define DEBUG_IP_PACKETS 0 /* 0=Disabled, 1=Enabled */
#if DEBUG_IP_PACKETS == 1
/* Calculate TCP/IP checksum */
static uint16_t calc_ip_csum(uint8_t *data, int len)
{
int i;
uint32_t accumulator = 0;
uint16_t *pointer = (uint16_t *) data;
for (i = len; i > 1; i -= 2) {
accumulator += *pointer;
pointer++;
}
if (len % 2)
accumulator += *pointer;
accumulator = (accumulator & 0xffff) + ((accumulator >> 16) & 0xffff);
accumulator += (accumulator >> 16) & 0xffff;
return (~accumulator);
}
/* Calculate TCP/IP checksum */
static uint16_t calc_tcpip_csum(const void *ctx, uint8_t *packet, int len)
{
uint8_t *buf;
uint16_t csum;
buf = talloc_zero_size(ctx, len);
memset(buf, 0, len);
memcpy(buf, packet + 12, 8);
buf[9] = packet[9];
buf[11] = (len - 20) & 0xFF;
buf[10] = (len - 20) >> 8 & 0xFF;
memcpy(buf + 12, packet + 20, len - 20);
csum = calc_ip_csum(buf, len - 20 + 12);
talloc_free(buf);
return csum;
}
/* Show some ip packet details */
static void debug_ip_packet(uint8_t *data, int len, int dir, char *info)
{
uint8_t tcp_flags;
char flags_debugmsg[256];
int len_short;
static unsigned int packet_count = 0;
static unsigned int tcp_csum_err_count = 0;
static unsigned int ip_csum_err_count = 0;
packet_count++;
if (len > 80)
len_short = 80;
else
len_short = len;
if (dir)
DEBUGP(DSNDCP, "%s: MS => SGSN: %s\n", info,
osmo_hexdump_nospc(data, len_short));
else
DEBUGP(DSNDCP, "%s: MS <= SGSN: %s\n", info,
osmo_hexdump_nospc(data, len_short));
DEBUGP(DSNDCP, "%s: Length.: %d\n", info, len);
DEBUGP(DSNDCP, "%s: NO.: %d\n", info, packet_count);
if (len < 20) {
DEBUGP(DSNDCP, "%s: Error: Short IP packet!\n", info);
return;
}
if (calc_ip_csum(data, 20) != 0) {
DEBUGP(DSNDCP, "%s: Bad IP-Header checksum!\n", info);
ip_csum_err_count++;
} else
DEBUGP(DSNDCP, "%s: IP-Header checksum ok.\n", info);
if (data[9] == 0x06) {
if (len < 40) {
DEBUGP(DSNDCP, "%s: Error: Short TCP packet!\n", info);
return;
}
DEBUGP(DSNDCP, "%s: Protocol type: TCP\n", info);
tcp_flags = data[33];
if (calc_tcpip_csum(NULL, data, len) != 0) {
DEBUGP(DSNDCP, "%s: Bad TCP checksum!\n", info);
tcp_csum_err_count++;
} else
DEBUGP(DSNDCP, "%s: TCP checksum ok.\n", info);
memset(flags_debugmsg, 0, sizeof(flags_debugmsg));
if (tcp_flags & 1)
strcat(flags_debugmsg, "FIN ");
if (tcp_flags & 2)
strcat(flags_debugmsg, "SYN ");
if (tcp_flags & 4)
strcat(flags_debugmsg, "RST ");
if (tcp_flags & 8)
strcat(flags_debugmsg, "PSH ");
if (tcp_flags & 16)
strcat(flags_debugmsg, "ACK ");
if (tcp_flags & 32)
strcat(flags_debugmsg, "URG ");
DEBUGP(DSNDCP, "%s: FLAGS: %s\n", info, flags_debugmsg);
} else if (data[9] == 0x11) {
DEBUGP(DSNDCP, "%s: Protocol type: UDP\n", info);
} else {
DEBUGP(DSNDCP, "%s: Protocol type: (%02x)\n", info, data[9]);
}
DEBUGP(DSNDCP, "%s: IP-Header checksum errors: %d\n", info,
ip_csum_err_count);
DEBUGP(DSNDCP, "%s: TCP-Checksum errors: %d\n", info,
tcp_csum_err_count);
}
#endif
/* Chapter 7.2: SN-PDU Formats */
struct sndcp_common_hdr {
/* octet 1 */
uint8_t nsapi:4;
uint8_t more:1;
uint8_t type:1;
uint8_t first:1;
uint8_t spare:1;
} __attribute__((packed));
/* PCOMP / DCOMP only exist in first fragment */
struct sndcp_comp_hdr {
/* octet 2 */
uint8_t pcomp:4;
uint8_t dcomp:4;
} __attribute__((packed));
struct sndcp_udata_hdr {
/* octet 3 */
uint8_t npdu_high:4;
uint8_t seg_nr:4;
/* octet 4 */
uint8_t npdu_low;
} __attribute__((packed));
static void *tall_sndcp_ctx;
/* A fragment queue entry, containing one framgent of a N-PDU */
struct defrag_queue_entry {
struct llist_head list;
/* segment number of this fragment */
uint32_t seg_nr;
/* length of the data area of this fragment */
uint32_t data_len;
/* pointer to the data of this fragment */
uint8_t *data;
};
LLIST_HEAD(gprs_sndcp_entities);
/* Check if any compression parameters are set in the sgsn configuration */
static inline int any_pcomp_or_dcomp_active(struct sgsn_instance *sgsn) {
if (sgsn->cfg.pcomp_rfc1144.active || sgsn->cfg.pcomp_rfc1144.passive ||
sgsn->cfg.dcomp_v42bis.active || sgsn->cfg.dcomp_v42bis.passive)
return true;
else
return false;
}
/* Enqueue a fragment into the defragment queue */
static int defrag_enqueue(struct gprs_sndcp_entity *sne, uint8_t seg_nr,
uint8_t *data, uint32_t data_len)
{
struct defrag_queue_entry *dqe;
dqe = talloc_zero(tall_sndcp_ctx, struct defrag_queue_entry);
if (!dqe)
return -ENOMEM;
dqe->data = talloc_zero_size(dqe, data_len);
if (!dqe->data) {
talloc_free(dqe);
return -ENOMEM;
}
dqe->seg_nr = seg_nr;
dqe->data_len = data_len;
llist_add(&dqe->list, &sne->defrag.frag_list);
if (seg_nr > sne->defrag.highest_seg)
sne->defrag.highest_seg = seg_nr;
sne->defrag.seg_have |= (1 << seg_nr);
sne->defrag.tot_len += data_len;
memcpy(dqe->data, data, data_len);
return 0;
}
/* return if we have all segments of this N-PDU */
static int defrag_have_all_segments(struct gprs_sndcp_entity *sne)
{
uint32_t seg_needed = 0;
unsigned int i;
/* create a bitmask of needed segments */
for (i = 0; i <= sne->defrag.highest_seg; i++)
seg_needed |= (1 << i);
if (seg_needed == sne->defrag.seg_have)
return 1;
return 0;
}
static struct defrag_queue_entry *defrag_get_seg(struct gprs_sndcp_entity *sne,
uint32_t seg_nr)
{
struct defrag_queue_entry *dqe;
llist_for_each_entry(dqe, &sne->defrag.frag_list, list) {
if (dqe->seg_nr == seg_nr) {
llist_del(&dqe->list);
return dqe;
}
}
return NULL;
}
/* Perform actual defragmentation and create an output packet */
static int defrag_segments(struct gprs_sndcp_entity *sne)
{
struct msgb *msg;
unsigned int seg_nr;
uint8_t *npdu;
int npdu_len;
int rc;
uint8_t *expnd = NULL;
LOGP(DSNDCP, LOGL_DEBUG, "TLLI=0x%08x NSAPI=%u: Defragment output PDU %u "
"num_seg=%u tot_len=%u\n", sne->lle->llme->tlli, sne->nsapi,
sne->defrag.npdu, sne->defrag.highest_seg, sne->defrag.tot_len);
msg = msgb_alloc_headroom(sne->defrag.tot_len+256, 128, "SNDCP Defrag");
if (!msg)
return -ENOMEM;
/* FIXME: message headers + identifiers */
npdu = msg->data;
for (seg_nr = 0; seg_nr <= sne->defrag.highest_seg; seg_nr++) {
struct defrag_queue_entry *dqe;
uint8_t *data;
dqe = defrag_get_seg(sne, seg_nr);
if (!dqe) {
LOGP(DSNDCP, LOGL_ERROR, "Segment %u missing\n", seg_nr);
msgb_free(msg);
return -EIO;
}
/* actually append the segment to the N-PDU */
data = msgb_put(msg, dqe->data_len);
memcpy(data, dqe->data, dqe->data_len);
/* release memory for the fragment queue entry */
talloc_free(dqe);
}
npdu_len = sne->defrag.tot_len;
/* FIXME: cancel timer */
/* actually send the N-PDU to the SGSN core code, which then
* hands it off to the correct GTP tunnel + GGSN via gtp_data_req() */
/* Decompress packet */
#if DEBUG_IP_PACKETS == 1
DEBUGP(DSNDCP, " \n");
DEBUGP(DSNDCP, ":::::::::::::::::::::::::::::::::::::::::::::::::::\n");
DEBUGP(DSNDCP, "===================================================\n");
#endif
if (any_pcomp_or_dcomp_active(sgsn)) {
expnd = talloc_zero_size(msg, npdu_len * MAX_DATADECOMPR_FAC +
MAX_HDRDECOMPR_INCR);
memcpy(expnd, npdu, npdu_len);
/* Apply data decompression */
rc = gprs_sndcp_dcomp_expand(expnd, npdu_len, sne->defrag.dcomp,
sne->defrag.data);
if (rc < 0) {
LOGP(DSNDCP, LOGL_ERROR,
"Data decompression failed!\n");
talloc_free(expnd);
return -EIO;
}
/* Apply header decompression */
rc = gprs_sndcp_pcomp_expand(expnd, rc, sne->defrag.pcomp,
sne->defrag.proto);
if (rc < 0) {
LOGP(DSNDCP, LOGL_ERROR,
"TCP/IP Header decompression failed!\n");
talloc_free(expnd);
return -EIO;
}
/* Modify npu length, expnd is handed directly handed
* over to gsn_rx_sndcp_ud_ind(), see below */
npdu_len = rc;
} else
expnd = npdu;
#if DEBUG_IP_PACKETS == 1
debug_ip_packet(expnd, npdu_len, 1, "defrag_segments()");
DEBUGP(DSNDCP, "===================================================\n");
DEBUGP(DSNDCP, ":::::::::::::::::::::::::::::::::::::::::::::::::::\n");
DEBUGP(DSNDCP, " \n");
#endif
/* Hand off packet to gtp */
rc = sgsn_rx_sndcp_ud_ind(&sne->ra_id, sne->lle->llme->tlli,
sne->nsapi, msg, npdu_len, expnd);
if (any_pcomp_or_dcomp_active(sgsn))
talloc_free(expnd);
return rc;
}
static int defrag_input(struct gprs_sndcp_entity *sne, struct msgb *msg,
uint8_t *hdr, unsigned int len)
{
struct sndcp_common_hdr *sch;
struct sndcp_udata_hdr *suh;
uint16_t npdu_num;
uint8_t *data;
int rc;
sch = (struct sndcp_common_hdr *) hdr;
if (sch->first) {
suh = (struct sndcp_udata_hdr *) (hdr + 1 + sizeof(struct sndcp_common_hdr));
} else
suh = (struct sndcp_udata_hdr *) (hdr + sizeof(struct sndcp_common_hdr));
data = (uint8_t *)suh + sizeof(struct sndcp_udata_hdr);
npdu_num = (suh->npdu_high << 8) | suh->npdu_low;
LOGP(DSNDCP, LOGL_DEBUG, "TLLI=0x%08x NSAPI=%u: Input PDU %u Segment %u "
"Length %u %s %s\n", sne->lle->llme->tlli, sne->nsapi, npdu_num,
suh->seg_nr, len, sch->first ? "F " : "", sch->more ? "M" : "");
if (sch->first) {
/* first segment of a new packet. Discard all leftover fragments of
* previous packet */
if (!llist_empty(&sne->defrag.frag_list)) {
struct defrag_queue_entry *dqe, *dqe2;
LOGP(DSNDCP, LOGL_INFO, "TLLI=0x%08x NSAPI=%u: Dropping "
"SN-PDU %u due to insufficient segments (%04x)\n",
sne->lle->llme->tlli, sne->nsapi, sne->defrag.npdu,
sne->defrag.seg_have);
llist_for_each_entry_safe(dqe, dqe2, &sne->defrag.frag_list, list) {
llist_del(&dqe->list);
talloc_free(dqe);
}
}
/* store the currently de-fragmented PDU number */
sne->defrag.npdu = npdu_num;
/* Re-set fragmentation state */
sne->defrag.no_more = sne->defrag.highest_seg = sne->defrag.seg_have = 0;
sne->defrag.tot_len = 0;
/* FIXME: (re)start timer */
}
if (sne->defrag.npdu != npdu_num) {
LOGP(DSNDCP, LOGL_INFO, "Segment for different SN-PDU "
"(%u != %u)\n", npdu_num, sne->defrag.npdu);
/* FIXME */
}
/* FIXME: check if seg_nr already exists */
/* make sure to subtract length of SNDCP header from 'len' */
rc = defrag_enqueue(sne, suh->seg_nr, data, len - (data - hdr));
if (rc < 0)
return rc;
if (!sch->more) {
/* this is suppsed to be the last segment of the N-PDU, but it
* might well be not the last to arrive */
sne->defrag.no_more = 1;
}
if (sne->defrag.no_more) {
/* we have already received the last segment before, let's check
* if all the previous segments exist */
if (defrag_have_all_segments(sne))
return defrag_segments(sne);
}
return 0;
}
static struct gprs_sndcp_entity *gprs_sndcp_entity_by_lle(const struct gprs_llc_lle *lle,
uint8_t nsapi)
{
struct gprs_sndcp_entity *sne;
llist_for_each_entry(sne, &gprs_sndcp_entities, list) {
if (sne->lle == lle && sne->nsapi == nsapi)
return sne;
}
return NULL;
}
static struct gprs_sndcp_entity *gprs_sndcp_entity_alloc(struct gprs_llc_lle *lle,
uint8_t nsapi)
{
struct gprs_sndcp_entity *sne;
sne = talloc_zero(tall_sndcp_ctx, struct gprs_sndcp_entity);
if (!sne)
return NULL;
sne->lle = lle;
sne->nsapi = nsapi;
sne->defrag.timer.data = sne;
//sne->fqueue.timer.cb = FIXME;
sne->rx_state = SNDCP_RX_S_FIRST;
INIT_LLIST_HEAD(&sne->defrag.frag_list);
llist_add(&sne->list, &gprs_sndcp_entities);
return sne;
}
/* Entry point for the SNSM-ACTIVATE.indication */
int sndcp_sm_activate_ind(struct gprs_llc_lle *lle, uint8_t nsapi)
{
LOGP(DSNDCP, LOGL_INFO, "SNSM-ACTIVATE.ind (lle=%p TLLI=%08x, "
"SAPI=%u, NSAPI=%u)\n", lle, lle->llme->tlli, lle->sapi, nsapi);
if (gprs_sndcp_entity_by_lle(lle, nsapi)) {
LOGP(DSNDCP, LOGL_ERROR, "Trying to ACTIVATE "
"already-existing entity (TLLI=%08x, NSAPI=%u)\n",
lle->llme->tlli, nsapi);
return -EEXIST;
}
if (!gprs_sndcp_entity_alloc(lle, nsapi)) {
LOGP(DSNDCP, LOGL_ERROR, "Out of memory during ACTIVATE\n");
return -ENOMEM;
}
return 0;
}
/* Entry point for the SNSM-DEACTIVATE.indication */
int sndcp_sm_deactivate_ind(struct gprs_llc_lle *lle, uint8_t nsapi)
{
struct gprs_sndcp_entity *sne;
LOGP(DSNDCP, LOGL_INFO, "SNSM-DEACTIVATE.ind (lle=%p, TLLI=%08x, "
"SAPI=%u, NSAPI=%u)\n", lle, lle->llme->tlli, lle->sapi, nsapi);
sne = gprs_sndcp_entity_by_lle(lle, nsapi);
if (!sne) {
LOGP(DSNDCP, LOGL_ERROR, "SNSM-DEACTIVATE.ind for non-"
"existing TLLI=%08x SAPI=%u NSAPI=%u\n", lle->llme->tlli,
lle->sapi, nsapi);
return -ENOENT;
}
llist_del(&sne->list);
/* frag queue entries are hierarchically allocated, so no need to
* free them explicitly here */
talloc_free(sne);
return 0;
}
/* Fragmenter state */
struct sndcp_frag_state {
uint8_t frag_nr;
struct msgb *msg; /* original message */
uint8_t *next_byte; /* first byte of next fragment */
struct gprs_sndcp_entity *sne;
void *mmcontext;
};
/* returns '1' if there are more fragments to send, '0' if none */
static int sndcp_send_ud_frag(struct sndcp_frag_state *fs,
uint8_t pcomp, uint8_t dcomp)
{
struct gprs_sndcp_entity *sne = fs->sne;
struct gprs_llc_lle *lle = sne->lle;
struct sndcp_common_hdr *sch;
struct sndcp_comp_hdr *scomph;
struct sndcp_udata_hdr *suh;
struct msgb *fmsg;
unsigned int max_payload_len;
unsigned int len;
uint8_t *data;
int rc, more;
fmsg = msgb_alloc_headroom(fs->sne->lle->params.n201_u+256, 128,
"SNDCP Frag");
if (!fmsg) {
msgb_free(fs->msg);
return -ENOMEM;
}
/* make sure lower layers route the fragment like the original */
msgb_tlli(fmsg) = msgb_tlli(fs->msg);
msgb_bvci(fmsg) = msgb_bvci(fs->msg);
msgb_nsei(fmsg) = msgb_nsei(fs->msg);
/* prepend common SNDCP header */
sch = (struct sndcp_common_hdr *) msgb_put(fmsg, sizeof(*sch));
sch->nsapi = sne->nsapi;
/* Set FIRST bit if we are the first fragment in a series */
if (fs->frag_nr == 0)
sch->first = 1;
sch->type = 1;
/* append the compression header for first fragment */
if (sch->first) {
scomph = (struct sndcp_comp_hdr *)
msgb_put(fmsg, sizeof(*scomph));
scomph->pcomp = pcomp;
scomph->dcomp = dcomp;
}
/* append the user-data header */
suh = (struct sndcp_udata_hdr *) msgb_put(fmsg, sizeof(*suh));
suh->npdu_low = sne->tx_npdu_nr & 0xff;
suh->npdu_high = (sne->tx_npdu_nr >> 8) & 0xf;
suh->seg_nr = fs->frag_nr % 0xf;
/* calculate remaining length to be sent */
len = (fs->msg->data + fs->msg->len) - fs->next_byte;
/* how much payload can we actually send via LLC? */
max_payload_len = lle->params.n201_u - (sizeof(*sch) + sizeof(*suh));
if (sch->first)
max_payload_len -= sizeof(*scomph);
/* check if we're exceeding the max */
if (len > max_payload_len)
len = max_payload_len;
/* copy the actual fragment data into our fmsg */
data = msgb_put(fmsg, len);
memcpy(data, fs->next_byte, len);
/* Increment fragment number and data pointer to next fragment */
fs->frag_nr++;
fs->next_byte += len;
/* determine if we have more fragemnts to send */
if ((fs->msg->data + fs->msg->len) <= fs->next_byte)
more = 0;
else
more = 1;
/* set the MORE bit of the SNDCP header accordingly */
sch->more = more;
rc = gprs_llc_tx_ui(fmsg, lle->sapi, 0, fs->mmcontext, true);
/* abort in case of error, do not advance frag_nr / next_byte */
if (rc < 0) {
msgb_free(fs->msg);
return rc;
}
if (!more) {
/* we've sent all fragments */
msgb_free(fs->msg);
memset(fs, 0, sizeof(*fs));
/* increment NPDU number for next frame */
sne->tx_npdu_nr = (sne->tx_npdu_nr + 1) % 0xfff;
return 0;
}
/* default: more fragments to send */
return 1;
}
/* Request transmission of a SN-PDU over specified LLC Entity + SAPI */
int sndcp_unitdata_req(struct msgb *msg, struct gprs_llc_lle *lle, uint8_t nsapi,
void *mmcontext)
{
struct gprs_sndcp_entity *sne;
struct sndcp_common_hdr *sch;
struct sndcp_comp_hdr *scomph;
struct sndcp_udata_hdr *suh;
struct sndcp_frag_state fs;
uint8_t pcomp = 0;
uint8_t dcomp = 0;
int rc;
/* Identifiers from UP: (TLLI, SAPI) + (BVCI, NSEI) */
/* Compress packet */
#if DEBUG_IP_PACKETS == 1
DEBUGP(DSNDCP, " \n");
DEBUGP(DSNDCP, ":::::::::::::::::::::::::::::::::::::::::::::::::::\n");
DEBUGP(DSNDCP, "===================================================\n");
debug_ip_packet(msg->data, msg->len, 0, "sndcp_initdata_req()");
#endif
if (any_pcomp_or_dcomp_active(sgsn)) {
/* Apply header compression */
rc = gprs_sndcp_pcomp_compress(msg->data, msg->len, &pcomp,
lle->llme->comp.proto, nsapi);
if (rc < 0) {
LOGP(DSNDCP, LOGL_ERROR,
"TCP/IP Header compression failed!\n");
return -EIO;
}
/* Fixup pointer locations and sizes in message buffer to match
* the new, compressed buffer size */
msgb_get(msg, msg->len);
msgb_put(msg, rc);
/* Apply data compression */
rc = gprs_sndcp_dcomp_compress(msg->data, msg->len, &dcomp,
lle->llme->comp.data, nsapi);
if (rc < 0) {
LOGP(DSNDCP, LOGL_ERROR, "Data compression failed!\n");
return -EIO;
}
/* Fixup pointer locations and sizes in message buffer to match
* the new, compressed buffer size */
msgb_get(msg, msg->len);
msgb_put(msg, rc);
}
#if DEBUG_IP_PACKETS == 1
DEBUGP(DSNDCP, "===================================================\n");
DEBUGP(DSNDCP, ":::::::::::::::::::::::::::::::::::::::::::::::::::\n");
DEBUGP(DSNDCP, " \n");
#endif
sne = gprs_sndcp_entity_by_lle(lle, nsapi);
if (!sne) {
LOGP(DSNDCP, LOGL_ERROR, "Cannot find SNDCP Entity\n");
msgb_free(msg);
return -EIO;
}
/* Check if we need to fragment this N-PDU into multiple SN-PDUs */
if (msg->len > lle->params.n201_u -
(sizeof(*sch) + sizeof(*suh) + sizeof(*scomph))) {
/* initialize the fragmenter state */
fs.msg = msg;
fs.frag_nr = 0;
fs.next_byte = msg->data;
fs.sne = sne;
fs.mmcontext = mmcontext;
/* call function to generate and send fragments until all
* of the N-PDU has been sent */
while (1) {
int rc = sndcp_send_ud_frag(&fs,pcomp,dcomp);
if (rc == 0)
return 0;
if (rc < 0)
return rc;
}
/* not reached */
return 0;
}
/* this is the non-fragmenting case where we only build 1 SN-PDU */
/* prepend the user-data header */
suh = (struct sndcp_udata_hdr *) msgb_push(msg, sizeof(*suh));
suh->npdu_low = sne->tx_npdu_nr & 0xff;
suh->npdu_high = (sne->tx_npdu_nr >> 8) & 0xf;
suh->seg_nr = 0;
sne->tx_npdu_nr = (sne->tx_npdu_nr + 1) % 0xfff;
scomph = (struct sndcp_comp_hdr *) msgb_push(msg, sizeof(*scomph));
scomph->pcomp = pcomp;
scomph->dcomp = dcomp;
/* prepend common SNDCP header */
sch = (struct sndcp_common_hdr *) msgb_push(msg, sizeof(*sch));
sch->first = 1;
sch->type = 1;
sch->nsapi = nsapi;
return gprs_llc_tx_ui(msg, lle->sapi, 0, mmcontext, true);
}
/* Section 5.1.2.17 LL-UNITDATA.ind */
int sndcp_llunitdata_ind(struct msgb *msg, struct gprs_llc_lle *lle,
uint8_t *hdr, uint16_t len)
{
struct gprs_sndcp_entity *sne;
struct sndcp_common_hdr *sch = (struct sndcp_common_hdr *)hdr;
struct sndcp_comp_hdr *scomph = NULL;
struct sndcp_udata_hdr *suh;
uint8_t *npdu;
uint16_t npdu_num __attribute__((unused));
int npdu_len;
int rc;
uint8_t *expnd = NULL;
sch = (struct sndcp_common_hdr *) hdr;
if (sch->first) {
scomph = (struct sndcp_comp_hdr *) (hdr + 1);
suh = (struct sndcp_udata_hdr *) (hdr + 1 + sizeof(struct sndcp_common_hdr));
} else
suh = (struct sndcp_udata_hdr *) (hdr + sizeof(struct sndcp_common_hdr));
if (sch->type == 0) {
LOGP(DSNDCP, LOGL_ERROR, "SN-DATA PDU at unitdata_ind() function\n");
return -EINVAL;
}
if (len < sizeof(*sch) + sizeof(*suh)) {
LOGP(DSNDCP, LOGL_ERROR, "SN-UNITDATA PDU too short (%u)\n", len);
return -EIO;
}
sne = gprs_sndcp_entity_by_lle(lle, sch->nsapi);
if (!sne) {
LOGP(DSNDCP, LOGL_ERROR, "Message for non-existing SNDCP Entity "
"(lle=%p, TLLI=%08x, SAPI=%u, NSAPI=%u)\n", lle,
lle->llme->tlli, lle->sapi, sch->nsapi);
return -EIO;
}
/* FIXME: move this RA_ID up to the LLME or even higher */
bssgp_parse_cell_id(&sne->ra_id, msgb_bcid(msg));
if (scomph) {
sne->defrag.pcomp = scomph->pcomp;
sne->defrag.dcomp = scomph->dcomp;
sne->defrag.proto = lle->llme->comp.proto;
sne->defrag.data = lle->llme->comp.data;
}
/* any non-first segment is by definition something to defragment
* as is any segment that tells us there are more segments */
if (!sch->first || sch->more)
return defrag_input(sne, msg, hdr, len);
npdu_num = (suh->npdu_high << 8) | suh->npdu_low;
npdu = (uint8_t *)suh + sizeof(*suh);
npdu_len = (msg->data + msg->len) - npdu - 3; /* -3 'removes' the FCS */
if (npdu_len <= 0) {
LOGP(DSNDCP, LOGL_ERROR, "Short SNDCP N-PDU: %d\n", npdu_len);
return -EIO;
}
/* actually send the N-PDU to the SGSN core code, which then
* hands it off to the correct GTP tunnel + GGSN via gtp_data_req() */
/* Decompress packet */
#if DEBUG_IP_PACKETS == 1
DEBUGP(DSNDCP, " \n");
DEBUGP(DSNDCP, ":::::::::::::::::::::::::::::::::::::::::::::::::::\n");
DEBUGP(DSNDCP, "===================================================\n");
#endif
if (any_pcomp_or_dcomp_active(sgsn)) {
expnd = talloc_zero_size(msg, npdu_len * MAX_DATADECOMPR_FAC +
MAX_HDRDECOMPR_INCR);
memcpy(expnd, npdu, npdu_len);
/* Apply data decompression */
rc = gprs_sndcp_dcomp_expand(expnd, npdu_len, sne->defrag.dcomp,
sne->defrag.data);
if (rc < 0) {
LOGP(DSNDCP, LOGL_ERROR,
"Data decompression failed!\n");
talloc_free(expnd);
return -EIO;
}
/* Apply header decompression */
rc = gprs_sndcp_pcomp_expand(expnd, rc, sne->defrag.pcomp,
sne->defrag.proto);
if (rc < 0) {
LOGP(DSNDCP, LOGL_ERROR,
"TCP/IP Header decompression failed!\n");
talloc_free(expnd);
return -EIO;
}
/* Modify npu length, expnd is handed directly handed
* over to gsn_rx_sndcp_ud_ind(), see below */
npdu_len = rc;
} else
expnd = npdu;
#if DEBUG_IP_PACKETS == 1
debug_ip_packet(expnd, npdu_len, 1, "sndcp_llunitdata_ind()");
DEBUGP(DSNDCP, "===================================================\n");
DEBUGP(DSNDCP, ":::::::::::::::::::::::::::::::::::::::::::::::::::\n");
DEBUGP(DSNDCP, " \n");
#endif
/* Hand off packet to gtp */
rc = sgsn_rx_sndcp_ud_ind(&sne->ra_id, lle->llme->tlli,
sne->nsapi, msg, npdu_len, expnd);
if (any_pcomp_or_dcomp_active(sgsn))
talloc_free(expnd);
return rc;
}
#if 0
/* Section 5.1.2.1 LL-RESET.ind */
static int sndcp_ll_reset_ind(struct gprs_sndcp_entity *se)
{
/* treat all outstanding SNDCP-LLC request type primitives as not sent */
/* reset all SNDCP XID parameters to default values */
LOGP(DSNDCP, LOGL_NOTICE, "not implemented.\n");
return 0;
}
static int sndcp_ll_status_ind()
{
/* inform the SM sub-layer by means of SNSM-STATUS.req */
LOGP(DSNDCP, LOGL_NOTICE, "not implemented.\n");
return 0;
}
static struct sndcp_state_list {{
uint32_t states;
unsigned int type;
int (*rout)(struct gprs_sndcp_entity *se, struct msgb *msg);
} sndcp_state_list[] = {
{ ALL_STATES,
LL_RESET_IND, sndcp_ll_reset_ind },
{ ALL_STATES,
LL_ESTABLISH_IND, sndcp_ll_est_ind },
{ SBIT(SNDCP_S_EST_RQD),
LL_ESTABLISH_RESP, sndcp_ll_est_ind },
{ SBIT(SNDCP_S_EST_RQD),
LL_ESTABLISH_CONF, sndcp_ll_est_conf },
{ SBIT(SNDCP_S_
};
static int sndcp_rx_llc_prim()
{
case LL_ESTABLISH_REQ:
case LL_RELEASE_REQ:
case LL_XID_REQ:
case LL_DATA_REQ:
LL_UNITDATA_REQ, /* TLLI, SN-PDU, Ref, QoS, Radio Prio, Ciph */
switch (prim) {
case LL_RESET_IND:
case LL_ESTABLISH_IND:
case LL_ESTABLISH_RESP:
case LL_ESTABLISH_CONF:
case LL_RELEASE_IND:
case LL_RELEASE_CONF:
case LL_XID_IND:
case LL_XID_RESP:
case LL_XID_CONF:
case LL_DATA_IND:
case LL_DATA_CONF:
case LL_UNITDATA_IND:
case LL_STATUS_IND:
}
}
#endif
/* Generate SNDCP-XID message */
static int gprs_llc_gen_sndcp_xid(uint8_t *bytes, int bytes_len, uint8_t nsapi)
{
int entity = 0;
LLIST_HEAD(comp_fields);
struct gprs_sndcp_pcomp_rfc1144_params rfc1144_params;
struct gprs_sndcp_comp_field rfc1144_comp_field;
struct gprs_sndcp_dcomp_v42bis_params v42bis_params;
struct gprs_sndcp_comp_field v42bis_comp_field;
memset(&rfc1144_comp_field, 0, sizeof(struct gprs_sndcp_comp_field));
memset(&v42bis_comp_field, 0, sizeof(struct gprs_sndcp_comp_field));
/* Setup rfc1144 */
if (sgsn->cfg.pcomp_rfc1144.active) {
rfc1144_params.nsapi[0] = nsapi;
rfc1144_params.nsapi_len = 1;
rfc1144_params.s01 = sgsn->cfg.pcomp_rfc1144.s01;
rfc1144_comp_field.p = 1;
rfc1144_comp_field.entity = entity;
rfc1144_comp_field.algo = RFC_1144;
rfc1144_comp_field.comp[RFC1144_PCOMP1] = 1;
rfc1144_comp_field.comp[RFC1144_PCOMP2] = 2;
rfc1144_comp_field.comp_len = RFC1144_PCOMP_NUM;
rfc1144_comp_field.rfc1144_params = &rfc1144_params;
entity++;
llist_add(&rfc1144_comp_field.list, &comp_fields);
}
/* Setup V.42bis */
if (sgsn->cfg.dcomp_v42bis.active) {
v42bis_params.nsapi[0] = nsapi;
v42bis_params.nsapi_len = 1;
v42bis_params.p0 = sgsn->cfg.dcomp_v42bis.p0;
v42bis_params.p1 = sgsn->cfg.dcomp_v42bis.p1;
v42bis_params.p2 = sgsn->cfg.dcomp_v42bis.p2;
v42bis_comp_field.p = 1;
v42bis_comp_field.entity = entity;
v42bis_comp_field.algo = V42BIS;
v42bis_comp_field.comp[V42BIS_DCOMP1] = 1;
v42bis_comp_field.comp_len = V42BIS_DCOMP_NUM;
v42bis_comp_field.v42bis_params = &v42bis_params;
entity++;
llist_add(&v42bis_comp_field.list, &comp_fields);
}
/* Do not attempt to compile anything if there is no data in the list */
if (llist_empty(&comp_fields))
return 0;
/* Compile bytestream */
return gprs_sndcp_compile_xid(bytes, bytes_len, &comp_fields,
DEFAULT_SNDCP_VERSION);
}
/* Set of SNDCP-XID bnegotiation (See also: TS 144 065,
* Section 6.8 XID parameter negotiation) */
int sndcp_sn_xid_req(struct gprs_llc_lle *lle, uint8_t nsapi)
{
/* Note: The specification requires the SNDCP-User to set of an
* SNDCP xid request. See also 3GPP TS 44.065, 6.8 XID parameter
* negotiation, Figure 11: SNDCP XID negotiation procedure. In
* our case the SNDCP-User is sgsn_libgtp.c, which calls
* sndcp_sn_xid_req directly. */
uint8_t l3params[1024];
int xid_len;
struct gprs_llc_xid_field xid_field_request;
/* Wipe off all compression entities and their states to
* get rid of possible leftovers from a previous session */
gprs_sndcp_comp_free(lle->llme->comp.proto);
gprs_sndcp_comp_free(lle->llme->comp.data);
lle->llme->comp.proto = gprs_sndcp_comp_alloc(lle->llme);
lle->llme->comp.data = gprs_sndcp_comp_alloc(lle->llme);
talloc_free(lle->llme->xid);
lle->llme->xid = NULL;
/* Generate compression parameter bytestream */
xid_len = gprs_llc_gen_sndcp_xid(l3params, sizeof(l3params), nsapi);
/* Send XID with the SNDCP-XID bytetsream included */
if (xid_len > 0) {
xid_field_request.type = GPRS_LLC_XID_T_L3_PAR;
xid_field_request.data = l3params;
xid_field_request.data_len = xid_len;
return gprs_ll_xid_req(lle, &xid_field_request);
}
/* When bytestream can not be generated, proceed without SNDCP-XID */
return gprs_ll_xid_req(lle, NULL);
}
/* Handle header compression entites */
static int handle_pcomp_entities(struct gprs_sndcp_comp_field *comp_field,
struct gprs_llc_lle *lle)
{
/* Note: This functions also transforms the comp_field into its
* echo form (strips comp values, resets propose bit etc...)
* the processed comp_fields can then be sent back as XID-
* Response without further modification. */
/* Delete propose bit */
comp_field->p = 0;
/* Process proposed parameters */
switch (comp_field->algo) {
case RFC_1144:
if (sgsn->cfg.pcomp_rfc1144.passive
&& comp_field->rfc1144_params->nsapi_len > 0) {
DEBUGP(DSNDCP,
"Accepting RFC1144 header compression...\n");
gprs_sndcp_comp_add(lle->llme, lle->llme->comp.proto,
comp_field);
} else {
DEBUGP(DSNDCP,
"Rejecting RFC1144 header compression...\n");
gprs_sndcp_comp_delete(lle->llme->comp.proto,
comp_field->entity);
comp_field->rfc1144_params->nsapi_len = 0;
}
break;
case RFC_2507:
/* RFC 2507 is not yet supported,
* so we set applicable nsapis to zero */
DEBUGP(DSNDCP, "Rejecting RFC2507 header compression...\n");
comp_field->rfc2507_params->nsapi_len = 0;
gprs_sndcp_comp_delete(lle->llme->comp.proto,
comp_field->entity);
break;
case ROHC:
/* ROHC is not yet supported,
* so we set applicable nsapis to zero */
DEBUGP(DSNDCP, "Rejecting ROHC header compression...\n");
comp_field->rohc_params->nsapi_len = 0;
gprs_sndcp_comp_delete(lle->llme->comp.proto,
comp_field->entity);
break;
}
return 0;
}
/* Hanle data compression entites */
static int handle_dcomp_entities(struct gprs_sndcp_comp_field *comp_field,
struct gprs_llc_lle *lle)
{
/* See note in handle_pcomp_entities() */
/* Delete propose bit */
comp_field->p = 0;
/* Process proposed parameters */
switch (comp_field->algo) {
case V42BIS:
if (sgsn->cfg.dcomp_v42bis.passive &&
comp_field->v42bis_params->nsapi_len > 0) {
DEBUGP(DSNDCP,
"Accepting V.42bis data compression...\n");
gprs_sndcp_comp_add(lle->llme, lle->llme->comp.data,
comp_field);
} else {
LOGP(DSNDCP, LOGL_DEBUG,
"Rejecting V.42bis data compression...\n");
gprs_sndcp_comp_delete(lle->llme->comp.data,
comp_field->entity);
comp_field->v42bis_params->nsapi_len = 0;
}
break;
case V44:
/* V44 is not yet supported,
* so we set applicable nsapis to zero */
DEBUGP(DSNDCP, "Rejecting V.44 data compression...\n");
comp_field->v44_params->nsapi_len = 0;
gprs_sndcp_comp_delete(lle->llme->comp.data,
comp_field->entity);
break;
}
return 0;
}
/* Process SNDCP-XID indication
* (See also: TS 144 065, Section 6.8 XID parameter negotiation) */
int sndcp_sn_xid_ind(struct gprs_llc_xid_field *xid_field_indication,
struct gprs_llc_xid_field *xid_field_response,
struct gprs_llc_lle *lle)
{
/* Note: This function computes the SNDCP-XID response that is sent
* back to the ms when a ms originated XID is received. The
* Input XID fields are directly processed and the result is directly
* handed back. */
int rc;
int compclass;
int version;
struct llist_head *comp_fields;
struct gprs_sndcp_comp_field *comp_field;
OSMO_ASSERT(xid_field_indication);
OSMO_ASSERT(xid_field_response);
OSMO_ASSERT(lle);
/* Parse SNDCP-CID XID-Field */
comp_fields = gprs_sndcp_parse_xid(&version, lle->llme,
xid_field_indication->data,
xid_field_indication->data_len,
NULL);
if (!comp_fields)
return -EINVAL;
/* Handle compression entites */
DEBUGP(DSNDCP, "SNDCP-XID-IND (ms):\n");
gprs_sndcp_dump_comp_fields(comp_fields, LOGL_DEBUG);
llist_for_each_entry(comp_field, comp_fields, list) {
compclass = gprs_sndcp_get_compression_class(comp_field);
if (compclass == SNDCP_XID_PROTOCOL_COMPRESSION)
rc = handle_pcomp_entities(comp_field, lle);
else if (compclass == SNDCP_XID_DATA_COMPRESSION)
rc = handle_dcomp_entities(comp_field, lle);
else {
gprs_sndcp_comp_delete(lle->llme->comp.proto,
comp_field->entity);
gprs_sndcp_comp_delete(lle->llme->comp.data,
comp_field->entity);
rc = 0;
}
if (rc < 0) {
talloc_free(comp_fields);
return -EINVAL;
}
}
DEBUGP(DSNDCP, "SNDCP-XID-RES (sgsn):\n");
gprs_sndcp_dump_comp_fields(comp_fields, LOGL_DEBUG);
/* Reserve some memory to store the modified SNDCP-XID bytes */
xid_field_response->data =
talloc_zero_size(lle->llme, xid_field_indication->data_len);
/* Set Type flag for response */
xid_field_response->type = GPRS_LLC_XID_T_L3_PAR;
/* Compile modified SNDCP-XID bytes */
rc = gprs_sndcp_compile_xid(xid_field_response->data,
xid_field_indication->data_len,
comp_fields, 0);
if (rc > 0)
xid_field_response->data_len = rc;
else {
talloc_free(xid_field_response->data);
xid_field_response->data = NULL;
xid_field_response->data_len = 0;
return -EINVAL;
}
talloc_free(comp_fields);
return 0;
}
/* Process SNDCP-XID indication
* (See also: TS 144 065, Section 6.8 XID parameter negotiation) */
int sndcp_sn_xid_conf(struct gprs_llc_xid_field *xid_field_conf,
struct gprs_llc_xid_field *xid_field_request,
struct gprs_llc_lle *lle)
{
/* Note: This function handles an incomming SNDCP-XID confirmiation.
* Since the confirmation fields may lack important parameters we
* will reconstruct these missing fields using the original request
* we have sent. After that we will create (or delete) the
* compression entites */
struct llist_head *comp_fields_req;
struct llist_head *comp_fields_conf;
struct gprs_sndcp_comp_field *comp_field;
int rc;
int compclass;
/* We need both, the confirmation that is sent back by the ms,
* and the original request we have sent. If one of this is missing
* we can not process the confirmation, the caller must check if
* request and confirmation fields are available. */
OSMO_ASSERT(xid_field_conf);
OSMO_ASSERT(xid_field_request);
/* Parse SNDCP-CID XID-Field */
comp_fields_req = gprs_sndcp_parse_xid(NULL, lle->llme,
xid_field_request->data,
xid_field_request->data_len,
NULL);
if (!comp_fields_req)
return -EINVAL;
DEBUGP(DSNDCP, "SNDCP-XID-REQ (sgsn):\n");
gprs_sndcp_dump_comp_fields(comp_fields_req, LOGL_DEBUG);
/* Parse SNDCP-CID XID-Field */
comp_fields_conf = gprs_sndcp_parse_xid(NULL, lle->llme,
xid_field_conf->data,
xid_field_conf->data_len,
comp_fields_req);
if (!comp_fields_conf)
return -EINVAL;
DEBUGP(DSNDCP, "SNDCP-XID-CONF (ms):\n");
gprs_sndcp_dump_comp_fields(comp_fields_conf, LOGL_DEBUG);
/* Handle compression entites */
llist_for_each_entry(comp_field, comp_fields_conf, list) {
compclass = gprs_sndcp_get_compression_class(comp_field);
if (compclass == SNDCP_XID_PROTOCOL_COMPRESSION)
rc = handle_pcomp_entities(comp_field, lle);
else if (compclass == SNDCP_XID_DATA_COMPRESSION)
rc = handle_dcomp_entities(comp_field, lle);
else {
gprs_sndcp_comp_delete(lle->llme->comp.proto,
comp_field->entity);
gprs_sndcp_comp_delete(lle->llme->comp.data,
comp_field->entity);
rc = 0;
}
if (rc < 0) {
talloc_free(comp_fields_req);
talloc_free(comp_fields_conf);
return -EINVAL;
}
}
talloc_free(comp_fields_req);
talloc_free(comp_fields_conf);
return 0;
}
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