neels has uploaded this change for review. (
https://gerrit.osmocom.org/c/osmo-upf/+/28312 )
Change subject: implement GTPv1-U ECHO response
......................................................................
implement GTPv1-U ECHO response
Accept data on the GTPv1-U socket and respond to GTPv1-U ECHO REQUEST
messages.
We should keep a deterministic recovery counter that increases with
every restart. As a quick and dirty way just use the current time at
startup for now, until osmo-upf reaches production maturity.
Related: OS#5599
Change-Id: I135370a7723e2c667ec681f50c21107cde63ea5b
---
M include/osmocom/upf/Makefile.am
M include/osmocom/upf/upf.h
A include/osmocom/upf/upf_gtpu_echo.h
M src/osmo-upf/Makefile.am
M src/osmo-upf/upf.c
M src/osmo-upf/upf_gtp.c
A src/osmo-upf/upf_gtpu_echo.c
7 files changed, 169 insertions(+), 0 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/osmo-upf refs/changes/12/28312/1
diff --git a/include/osmocom/upf/Makefile.am b/include/osmocom/upf/Makefile.am
index 333132c..127e03e 100644
--- a/include/osmocom/upf/Makefile.am
+++ b/include/osmocom/upf/Makefile.am
@@ -4,6 +4,7 @@
up_session.h \
upf.h \
upf_gtp.h \
+ upf_gtpu_echo.h \
upf_nft.h \
up_gtp_action.h \
$(NULL)
diff --git a/include/osmocom/upf/upf.h b/include/osmocom/upf/upf.h
index 49217c6..6f4d01c 100644
--- a/include/osmocom/upf/upf.h
+++ b/include/osmocom/upf/upf.h
@@ -84,6 +84,8 @@
struct mnl_socket *nl;
int32_t genl_id;
+
+ uint8_t recovery_count;
} gtp;
/* Tunnel forwarding via linux netfilter */
diff --git a/include/osmocom/upf/upf_gtpu_echo.h
b/include/osmocom/upf/upf_gtpu_echo.h
new file mode 100644
index 0000000..2575424
--- /dev/null
+++ b/include/osmocom/upf/upf_gtpu_echo.h
@@ -0,0 +1,4 @@
+/* GTP-U ECHO implementation for osmo-upf */
+#pragma once
+
+int upf_gtpu_echo_setup(struct upf_gtp_dev *dev);
diff --git a/src/osmo-upf/Makefile.am b/src/osmo-upf/Makefile.am
index 1265051..1d43ee8 100644
--- a/src/osmo-upf/Makefile.am
+++ b/src/osmo-upf/Makefile.am
@@ -37,6 +37,7 @@
up_session.c \
upf.c \
upf_gtp.c \
+ upf_gtpu_echo.c \
upf_nft.c \
upf_vty.c \
$(NULL)
diff --git a/src/osmo-upf/upf.c b/src/osmo-upf/upf.c
index 9677147..2faa558 100644
--- a/src/osmo-upf/upf.c
+++ b/src/osmo-upf/upf.c
@@ -53,6 +53,10 @@
.nft = {
.priority = -300,
},
+ .gtp = {
+ /* TODO: recovery count state file; use lower byte of
current time, poor person's random. */
+ .recovery_count = time(NULL),
+ },
};
INIT_LLIST_HEAD(&g_upf->gtp.vty_cfg.devs);
diff --git a/src/osmo-upf/upf_gtp.c b/src/osmo-upf/upf_gtp.c
index 84d74d1..4524795 100644
--- a/src/osmo-upf/upf_gtp.c
+++ b/src/osmo-upf/upf_gtp.c
@@ -36,6 +36,7 @@
#include <osmocom/upf/upf.h>
#include <osmocom/upf/upf_gtp.h>
+#include <osmocom/upf/upf_gtpu_echo.h>
#define LOG_GTP_TUN(TUN, LEVEL, FMT, ARGS...) \
LOGP(DGTP, LEVEL, "%s: " FMT, upf_gtp_tun_to_str_c(OTC_SELECT, (TUN)),
##ARGS)
@@ -221,6 +222,8 @@
return -EIO;
}
+ upf_gtpu_echo_setup(dev);
+
return 0;
}
diff --git a/src/osmo-upf/upf_gtpu_echo.c b/src/osmo-upf/upf_gtpu_echo.c
new file mode 100644
index 0000000..24452b7
--- /dev/null
+++ b/src/osmo-upf/upf_gtpu_echo.c
@@ -0,0 +1,154 @@
+/* GTP-U ECHO implementation for osmo-upf */
+
+#include <stdint.h>
+#include <errno.h>
+
+#include <osmocom/core/endian.h>
+#include <osmocom/core/socket.h>
+#include <osmocom/core/msgb.h>
+
+#include <osmocom/upf/upf.h>
+#include <osmocom/upf/upf_gtp.h>
+
+#define GTP1U_PORT 2152
+
+enum gtp1u_msgt {
+ GTP1U_MSGTYPE_ECHO_REQ = 1,
+ GTP1U_MSGTYPE_ECHO_RSP = 2,
+};
+
+enum gtp1u_iei {
+ GTP1U_IEI_RECOVERY = 14,
+};
+
+/* 3GPP TS 29.281 */
+struct gtp1u_hdr {
+#if OSMO_IS_LITTLE_ENDIAN
+ uint8_t pn:1, /*< N-PDU Number flag */
+ s:1, /*< Sequence number flag */
+ e:1, /*< Extension header flag */
+ spare:1,
+ pt:1, /*< Protocol Type: GTP=1, GTP'=0 */
+ version:3; /*< Version: 1 */
+#elif OSMO_IS_BIG_ENDIAN
+ uint8_t version:3, pt:1, spare:1, e:1, s:1, pn:1;
+#endif
+ uint8_t msg_type;
+ uint16_t length;
+ uint32_t tei; /*< 05 - 08 Tunnel Endpoint ID */
+ union {
+ uint8_t data1[0];
+ struct {
+ uint16_t seq_nr;
+ uint8_t n_pdu_nr;
+ uint8_t next_ext_type;
+ } ext;
+ };
+ uint8_t data2[0];
+} __attribute__((packed));
+
+static int rx_echo_req(struct upf_gtp_dev *dev, const struct osmo_sockaddr
*remote, const struct gtp1u_hdr *rx_h)
+{
+ struct msgb *msg;
+ struct gtp1u_hdr *tx_h;
+ int rc;
+
+ if (!rx_h->s) {
+ LOG_GTP_DEV(dev, LOGL_ERROR, "rx GTPv1-U ECHO REQ without
sequence nr\n");
+ return -1;
+ }
+
+ msg = msgb_alloc_headroom(1024, 128, "GTP-echo-resp");
+ tx_h = (void*)msgb_put(msg, sizeof(*tx_h));
+
+ *tx_h = (struct gtp1u_hdr){
+ /* 3GPP TS 29.281 5.1 defines that the ECHO REQ & RESP shall
contain a sequence nr */
+ .s = 1,
+ .pt = 1,
+ .version = 1,
+ .msg_type = GTP1U_MSGTYPE_ECHO_RSP,
+ .ext = {
+ .seq_nr = rx_h->ext.seq_nr,
+ },
+ };
+
+ OSMO_ASSERT(msg->tail == tx_h->data2);
+
+ /* ECHO RESPONSE shall contain a recovery counter */
+ msgb_put_u8(msg, GTP1U_IEI_RECOVERY);
+ msgb_put_u8(msg, g_upf->gtp.recovery_count);
+
+ osmo_store16be(msg->tail - tx_h->data1, &tx_h->length);
+
+ rc = sendto(dev->gtpv1.ofd.fd, msgb_data(msg), msgb_length(msg), 0,
&remote->u.sa, sizeof(*remote));
+ if (rc < 0) {
+ int err = errno;
+ LOG_GTP_DEV(dev, LOGL_ERROR, "GTP1-U sendto(len=%d, to=%s):
%s\n", msgb_length(msg),
+ osmo_sockaddr_to_str(remote), strerror(err));
+ }
+ return rc;
+}
+
+int upf_gtpu_echo_read_cb(struct osmo_fd *ofd, unsigned int what)
+{
+ struct upf_gtp_dev *dev = ofd->data;
+
+ ssize_t sz;
+ uint8_t buf[4096];
+ struct osmo_sockaddr remote;
+ socklen_t remote_len = sizeof(remote);
+ const struct gtp1u_hdr *h;
+ uint16_t h_length;
+
+ if ((sz = recvfrom(dev->gtpv1.ofd.fd, buf, sizeof(buf), 0,
&remote.u.sa, &remote_len)) < 0) {
+ LOG_GTP_DEV(dev, LOGL_ERROR, "recvfrom() failed: %s\n",
strerror(errno));
+ return -1;
+ }
+ if (sz == 0) {
+ LOG_GTP_DEV(dev, LOGL_ERROR, "recvfrom() yields zero bytes\n");
+ return -1;
+ }
+
+ /* A GTPv1-U header of size 8 is valid, but this code expects to handle
only ECHO REQUEST messages. These are
+ * required to have a sequence number, hence this check here
consciously uses the full sizeof(*h) == 12. */
+ if (sz < sizeof(*h)) {
+ LOG_GTP_DEV(dev, LOGL_ERROR, "rx GTP packet smaller than the
GTPv1-U header + sequence nr: %zd < %zu\n",
+ sz, sizeof(*h));
+ return -1;
+ }
+
+ h = (const struct gtp1u_hdr *)buf;
+ if (h->version != 1) {
+ LOG_GTP_DEV(dev, LOGL_ERROR, "rx GTP v%u: only GTP version 1
supported\n", h->version);
+ return -1;
+ }
+
+ h_length = osmo_load16be(&h->length);
+ if (offsetof(struct gtp1u_hdr, data1) + h_length > sz) {
+ LOG_GTP_DEV(dev, LOGL_ERROR, "rx GTP: header + h.length = %zu >
received bytes = %zd\n",
+ offsetof(struct gtp1u_hdr, data1) + h_length, sz);
+ return -1;
+ }
+
+ switch (h->msg_type) {
+ case GTP1U_MSGTYPE_ECHO_REQ:
+ return rx_echo_req(dev, &remote, h);
+ default:
+ LOG_GTP_DEV(dev, LOGL_ERROR, "rx: GTPv1-U message type %u not
supported\n", h->msg_type);
+ return -1;
+ }
+
+ return 0;
+}
+
+int upf_gtpu_echo_setup(struct upf_gtp_dev *dev)
+{
+ if (dev->gtpv1.ofd.fd == -1) {
+ LOGP(DGTP, LOGL_ERROR, "Cannot setup GTP-U ECHO: GTP-v1 socket
not initialized\n");
+ return -EINVAL;
+ }
+
+ dev->gtpv1.ofd.cb = upf_gtpu_echo_read_cb;
+ dev->gtpv1.ofd.data = dev;
+ return osmo_fd_register(&dev->gtpv1.ofd);
+}
--
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Gerrit-Project: osmo-upf
Gerrit-Branch: master
Gerrit-Change-Id: I135370a7723e2c667ec681f50c21107cde63ea5b
Gerrit-Change-Number: 28312
Gerrit-PatchSet: 1
Gerrit-Owner: neels <[email protected]>
Gerrit-MessageType: newchange
