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8484a5af60
If eg. PCRF or AAA diameter link is not yet ready (eg. PCRF crashed), and a client sends a CreateSessionRequest announcing its ow F-TEID, then open5gs-smfd answers with Create Session Response Cause= "Remote peer not responding", but it is not setting the received F-TEID in the header of the response, instead it sends with TEI=0. As a result, the peer cannot match the CreateSessionResponse, and needs to rely on its own timeout timer to figure out that specific request failed. To address this issue, I modified the GTP Response message to check the Sender F-TEID and send it accordingly, setting the destination TEID to the value of the Sender F-TEID. I've made this modification only for SMF, but MME and SGW-C have not done so; if you need to, you can work from the examples in SMF. Similarly, the same situation can happen with PFCP. If anyone needs to do this in the future, I think you can work on it this way.
248 lines
8.1 KiB
C
248 lines
8.1 KiB
C
/*
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* Copyright (C) 2019 by Sukchan Lee <acetcom@gmail.com>
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*
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* This file is part of Open5GS.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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#include "ogs-gtp.h"
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int ogs_gtpu_parse_header(
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ogs_gtp2_header_desc_t *header_desc, ogs_pkbuf_t *pkbuf)
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{
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ogs_gtp2_header_t *gtp_h = NULL;
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ogs_gtp2_extension_header_t ext_hdesc;
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uint8_t *ext_h = NULL;
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uint16_t len = 0;
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int i;
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ogs_assert(pkbuf);
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ogs_assert(pkbuf->data);
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gtp_h = (ogs_gtp2_header_t *)pkbuf->data;
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if (header_desc) {
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memset(header_desc, 0, sizeof(*header_desc));
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header_desc->flags = gtp_h->flags;
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header_desc->type = gtp_h->type;
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header_desc->teid = be32toh(gtp_h->teid);
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}
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len = OGS_GTPV1U_HEADER_LEN;
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if (pkbuf->len < len) {
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ogs_error("the length of the packet is insufficient[%d:%d]",
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pkbuf->len, len);
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return -1;
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}
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if (gtp_h->flags & OGS_GTPU_FLAGS_E) {
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len += OGS_GTPV1U_EXTENSION_HEADER_LEN;
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if (pkbuf->len < len) {
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ogs_error("the length of the packet is insufficient[%d:%d]",
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pkbuf->len, len);
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return -1;
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}
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/*
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* TS29.281
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* 5.2.1 General format of the GTP-U Extension Header
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*
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* If no such Header follows,
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* then the value of the Next Extension Header Type shall be 0. */
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i = 0;
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while (*(ext_h = (((uint8_t *)gtp_h) + len - 1)) &&
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i < OGS_GTP2_NUM_OF_EXTENSION_HEADER) {
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/*
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* The length of the Extension header shall be defined
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* in a variable length of 4 octets, i.e. m+1 = n*4 octets,
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* where n is a positive integer.
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*/
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len += (*(++ext_h)) * 4;
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if (*ext_h == 0) {
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ogs_error("No length in the Extension header");
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return -1;
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}
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if (((*ext_h) * 4) > OGS_GTP2_MAX_EXTENSION_HEADER_LEN) {
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ogs_error("Overflow length : %d", (*ext_h));
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return -1;
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}
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if (pkbuf->len < len) {
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ogs_error("the length of the packet is insufficient[%d:%d]",
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pkbuf->len, len);
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return -1;
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}
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if (!header_desc) /* Skip to extract header content */
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continue;
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/* Copy Header Content */
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memcpy(&ext_hdesc.array[i], ext_h-1, (*ext_h) * 4);
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switch (ext_hdesc.array[i].type) {
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case OGS_GTP2_EXTENSION_HEADER_TYPE_PDU_SESSION_CONTAINER:
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header_desc->pdu_type = ext_hdesc.array[i].pdu_type;
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if (ext_hdesc.array[i].pdu_type ==
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OGS_GTP2_EXTENSION_HEADER_PDU_TYPE_UL_PDU_SESSION_INFORMATION) {
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header_desc->qos_flow_identifier =
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ext_hdesc.array[i].qos_flow_identifier;
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ogs_trace(" QFI [0x%x]",
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header_desc->qos_flow_identifier);
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}
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break;
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case OGS_GTP2_EXTENSION_HEADER_TYPE_UDP_PORT:
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header_desc->udp.presence = true;
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header_desc->udp.port = be16toh(ext_hdesc.array[i].udp_port);
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ogs_trace(" UDP Port [%d]", header_desc->udp.port);
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break;
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case OGS_GTP2_EXTENSION_HEADER_TYPE_PDCP_NUMBER:
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header_desc->pdcp_number_presence = true;
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header_desc->pdcp_number =
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be16toh(ext_hdesc.array[i].pdcp_number);
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ogs_trace(" PDCP Number [%d]", header_desc->pdcp_number);
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break;
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default:
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break;
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}
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i++;
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}
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if (i >= OGS_GTP2_NUM_OF_EXTENSION_HEADER) {
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ogs_error("The number of extension headers is limited to [%d]", i);
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return -1;
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}
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} else if (gtp_h->flags & (OGS_GTPU_FLAGS_S|OGS_GTPU_FLAGS_PN)) {
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/*
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* If and only if one or more of these three flags are set,
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* the fields Sequence Number, N-PDU and Extension Header
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* shall be present. The sender shall set all the bits of
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* the unused fields to zero. The receiver shall not evaluate
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* the unused fields.
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* For example, if only the E flag is set to 1, then
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* the N-PDU Number and Sequence Number fields shall also be present,
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* but will not have meaningful values and shall not be evaluated.
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*/
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len += 4;
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}
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if (pkbuf->len < len) {
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ogs_error("the length of the packet is insufficient[%d:%d]",
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pkbuf->len, len);
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return -1;
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}
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return len;
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}
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uint16_t ogs_in_cksum(uint16_t *addr, int len)
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{
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int nleft = len;
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uint32_t sum = 0;
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uint16_t *w = addr;
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uint16_t answer = 0;
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// Adding 16 bits sequentially in sum
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while (nleft > 1) {
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sum += *w;
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nleft -= 2;
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w++;
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}
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// If an odd byte is left
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if (nleft == 1) {
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*(uint8_t *) (&answer) = *(uint8_t *) w;
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sum += answer;
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}
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sum = (sum >> 16) + (sum & 0xffff);
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sum += (sum >> 16);
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answer = ~sum;
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return answer;
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}
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void ogs_gtp2_sender_f_teid(
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ogs_gtp2_sender_f_teid_t *sender_f_teid, ogs_gtp2_message_t *message)
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{
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ogs_gtp2_tlv_f_teid_t *tlv_f_teid = NULL;
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ogs_gtp2_f_teid_t *f_teid = NULL;
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ogs_assert(sender_f_teid);
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ogs_assert(message);
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memset(sender_f_teid, 0, sizeof(*sender_f_teid));
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switch (message->h.type) {
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case OGS_GTP2_CREATE_SESSION_REQUEST_TYPE:
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tlv_f_teid = &message->create_session_request.
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sender_f_teid_for_control_plane;
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break;
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case OGS_GTP2_CREATE_SESSION_RESPONSE_TYPE:
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tlv_f_teid = &message->create_session_response.
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sender_f_teid_for_control_plane;
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break;
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case OGS_GTP2_MODIFY_BEARER_REQUEST_TYPE:
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tlv_f_teid = &message->modify_bearer_request.
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sender_f_teid_for_control_plane;
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break;
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case OGS_GTP2_DELETE_SESSION_REQUEST_TYPE:
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tlv_f_teid = &message->delete_session_request.
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sender_f_teid_for_control_plane;
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break;
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case OGS_GTP2_MODIFY_BEARER_COMMAND_TYPE:
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tlv_f_teid = &message->modify_bearer_command.
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sender_f_teid_for_control_plane;
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break;
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case OGS_GTP2_DELETE_BEARER_COMMAND_TYPE:
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tlv_f_teid = &message->delete_bearer_command.
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sender_f_teid_for_control_plane;
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break;
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case OGS_GTP2_BEARER_RESOURCE_COMMAND_TYPE:
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tlv_f_teid = &message->bearer_resource_command.
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sender_f_teid_for_control_plane;
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break;
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case OGS_GTP2_CREATE_INDIRECT_DATA_FORWARDING_TUNNEL_REQUEST_TYPE:
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tlv_f_teid = &message->create_indirect_data_forwarding_tunnel_request.
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sender_f_teid_for_control_plane;
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break;
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case OGS_GTP2_CREATE_INDIRECT_DATA_FORWARDING_TUNNEL_RESPONSE_TYPE:
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tlv_f_teid = &message->create_indirect_data_forwarding_tunnel_response.
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sender_f_teid_for_control_plane;
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break;
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case OGS_GTP2_DOWNLINK_DATA_NOTIFICATION_TYPE:
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tlv_f_teid = &message->downlink_data_notification.
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sender_f_teid_for_control_plane;
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break;
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case OGS_GTP2_MODIFY_ACCESS_BEARERS_REQUEST_TYPE:
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tlv_f_teid = &message->modify_access_bearers_request.
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sender_f_teid_for_control_plane;
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default:
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break;
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}
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if (tlv_f_teid && tlv_f_teid->presence && (f_teid = tlv_f_teid->data)) {
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sender_f_teid->teid_presence = true;
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sender_f_teid->teid = be32toh(f_teid->teid);
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}
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}
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