[PATCH iproute2-next v2 0/2] GTP support for ip link and tc flower

[PATCH iproute2-next v2 0/2] GTP support for ip link and tc flower

[Wojciech Drewek]

This patch series introduces GTP support to iproute2. Since this patch
series it is possible to create net devices of GTP type. Then, those
devices can be used in tc in order to offload GTP packets. New field
in tc flower (gtp_opts) can be used to match on QFI and PDU type.

Kernel changes:
https://lore.kernel.org/netdev/20220204164929.10356-1-marcin.szycik@linux.intel.com/T/#t

Wojciech Drewek (2):
  ip: GTP support in ip link
  f_flower: Implement gtp options support

 include/uapi/linux/if_link.h |   1 +
 include/uapi/linux/pkt_cls.h |  16 +++++
 ip/Makefile                  |   2 +-
 ip/iplink.c                  |   2 +-
 ip/iplink_gtp.c              | 123 +++++++++++++++++++++++++++++++++++
 man/man8/ip-link.8.in        |  29 ++++++++-
 man/man8/tc-flower.8         |  10 +++
 tc/f_flower.c                | 113 ++++++++++++++++++++++++++++++++
 8 files changed, 293 insertions(+), 3 deletions(-)
 create mode 100644 ip/iplink_gtp.c

-- 
2.31.1

[PATCH iproute2-next v2 1/2] ip: GTP support in ip link

[Wojciech Drewek]

Support for creating GTP devices through ip link. Two arguments
can be specified by the user when adding device of the GTP type.
 - role (sgsn or ggsn) - indicates whether we are on the GGSN or SGSN
 - hsize - indicates the size of the hash table where PDP sessions
   are stored

IFLA_GTP_FD0 and IFLA_GTP_FD1 arguments would not be provided. Those
are file descriptores to the sockets created in the userspace. Since
we are not going to create sockets in ip link, we don't have to
provide them.

Signed-off-by: Wojciech Drewek <wojciech.drewek@intel.com>
---
v2: use SPDX tag, use strcmp() instead of matches(), parse
    IFLA_GTP_RESTART_COUNT arg
---
 include/uapi/linux/if_link.h |   1 +
 ip/Makefile                  |   2 +-
 ip/iplink.c                  |   2 +-
 ip/iplink_gtp.c              | 123 +++++++++++++++++++++++++++++++++++
 man/man8/ip-link.8.in        |  29 ++++++++-
 5 files changed, 154 insertions(+), 3 deletions(-)
 create mode 100644 ip/iplink_gtp.c

diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 41708e26a3c9..c6713aecfa85 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -820,6 +820,7 @@ enum {
 	IFLA_GTP_FD1,
 	IFLA_GTP_PDP_HASHSIZE,
 	IFLA_GTP_ROLE,
+	IFLA_GTP_RESTART_COUNT,
 	__IFLA_GTP_MAX,
 };
 #define IFLA_GTP_MAX (__IFLA_GTP_MAX - 1)
diff --git a/ip/Makefile b/ip/Makefile
index 2a7a51c313c6..06ba60b341af 100644
--- a/ip/Makefile
+++ b/ip/Makefile
@@ -12,7 +12,7 @@ IPOBJ=ip.o ipaddress.o ipaddrlabel.o iproute.o iprule.o ipnetns.o \
     iplink_geneve.o iplink_vrf.o iproute_lwtunnel.o ipmacsec.o ipila.o \
     ipvrf.o iplink_xstats.o ipseg6.o iplink_netdevsim.o iplink_rmnet.o \
     ipnexthop.o ipmptcp.o iplink_bareudp.o iplink_wwan.o ipioam6.o \
-    iplink_amt.o
+    iplink_amt.o iplink_gtp.o
 
 RTMONOBJ=rtmon.o
 
diff --git a/ip/iplink.c b/ip/iplink.c
index a3ea775d2b23..3d1127f437e4 100644
--- a/ip/iplink.c
+++ b/ip/iplink.c
@@ -57,7 +57,7 @@ void iplink_types_usage(void)
 		"          macsec | macvlan | macvtap |\n"
 		"          netdevsim | nlmon | rmnet | sit | team | team_slave |\n"
 		"          vcan | veth | vlan | vrf | vti | vxcan | vxlan | wwan |\n"
-		"          xfrm }\n");
+		"          xfrm | gtp }\n");
 }
 
 void iplink_usage(void)
diff --git a/ip/iplink_gtp.c b/ip/iplink_gtp.c
new file mode 100644
index 000000000000..79ef0da92fb3
--- /dev/null
+++ b/ip/iplink_gtp.c
@@ -0,0 +1,123 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <stdio.h>
+
+#include "rt_names.h"
+#include "utils.h"
+#include "ip_common.h"
+
+#define GTP_ATTRSET(attrs, type) (((attrs) & (1L << (type))) != 0)
+
+static void print_explain(FILE *f)
+{
+	fprintf(f,
+		"Usage: ... gtp role ROLE\n"
+		"		[ hsize HSIZE ]\n"
+		"		[ restart_count RESTART_COUNT ]\n"
+		"\n"
+		"Where:	ROLE		:= { sgsn | ggsn }\n"
+		"	HSIZE		:= 1-131071\n"
+		"	RESTART_COUNT	:= 0-255\n"
+	);
+}
+
+static void check_duparg(__u32 *attrs, int type, const char *key,
+			 const char *argv)
+{
+	if (!GTP_ATTRSET(*attrs, type)) {
+		*attrs |= (1L << type);
+		return;
+	}
+	duparg2(key, argv);
+}
+
+static int gtp_parse_opt(struct link_util *lu, int argc, char **argv,
+			 struct nlmsghdr *n)
+{
+	__u32 attrs = 0;
+
+	while (argc > 0) {
+		if (!strcmp(*argv, "role")) {
+			NEXT_ARG();
+			check_duparg(&attrs, IFLA_GTP_ROLE, "role", *argv);
+			if (!strcmp(*argv, "sgsn"))
+				addattr32(n, 1024, IFLA_GTP_ROLE, GTP_ROLE_SGSN);
+			else if (!strcmp(*argv, "ggsn"))
+				addattr32(n, 1024, IFLA_GTP_ROLE, GTP_ROLE_GGSN);
+			else
+				invarg("invalid role, use sgsn or ggsn", *argv);
+		} else if (!strcmp(*argv, "hsize")) {
+			__u32 hsize;
+
+			NEXT_ARG();
+			check_duparg(&attrs, IFLA_GTP_PDP_HASHSIZE, "hsize", *argv);
+
+			if (get_u32(&hsize, *argv, 0))
+				invarg("invalid PDP hash size", *argv);
+			if (hsize >= 1u << 17)
+				invarg("PDP hash size too big", *argv);
+			addattr32(n, 1024, IFLA_GTP_PDP_HASHSIZE, hsize);
+		} else if (!strcmp(*argv, "restart_count")) {
+			__u8 restart_count;
+
+			NEXT_ARG();
+			check_duparg(&attrs, IFLA_GTP_RESTART_COUNT, "restart_count", *argv);
+
+			if (get_u8(&restart_count, *argv, 10))
+				invarg("invalid restart_count", *argv);
+			addattr8(n, 1024, IFLA_GTP_RESTART_COUNT, restart_count);
+		} else if (!strcmp(*argv, "help")) {
+			print_explain(stderr);
+			return -1;
+		}
+		argc--, argv++;
+	}
+
+	if (!GTP_ATTRSET(attrs, IFLA_GTP_ROLE)) {
+		fprintf(stderr, "gtp: role of the gtp device was not specified\n");
+		return -1;
+	}
+
+	if (!GTP_ATTRSET(attrs, IFLA_GTP_PDP_HASHSIZE))
+		addattr32(n, 1024, IFLA_GTP_PDP_HASHSIZE, 1024);
+
+	return 0;
+}
+
+static void gtp_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
+{
+
+	if (tb[IFLA_GTP_ROLE]) {
+		__u32 role = rta_getattr_u32(tb[IFLA_GTP_ROLE]);
+
+		print_string(PRINT_ANY, "role", "role %s ",
+			     role == GTP_ROLE_SGSN ? "sgsn" : "ggsn");
+	}
+
+	if (tb[IFLA_GTP_PDP_HASHSIZE]) {
+		__u32 hsize = rta_getattr_u32(tb[IFLA_GTP_PDP_HASHSIZE]);
+
+		print_uint(PRINT_ANY, "hsize", "hsize %u ", hsize);
+	}
+
+	if (tb[IFLA_GTP_RESTART_COUNT]) {
+		__u8 restart_count = rta_getattr_u8(tb[IFLA_GTP_RESTART_COUNT]);
+
+		print_uint(PRINT_ANY, "restart_count",
+			   "restart_count %u ", restart_count);
+	}
+}
+
+static void gtp_print_help(struct link_util *lu, int argc, char **argv,
+			   FILE *f)
+{
+	print_explain(f);
+}
+
+struct link_util gtp_link_util = {
+	.id		= "gtp",
+	.maxattr	= IFLA_GTP_MAX,
+	.parse_opt	= gtp_parse_opt,
+	.print_opt	= gtp_print_opt,
+	.print_help	= gtp_print_help,
+};
diff --git a/man/man8/ip-link.8.in b/man/man8/ip-link.8.in
index 19a0c9cab811..9c754c4b99cf 100644
--- a/man/man8/ip-link.8.in
+++ b/man/man8/ip-link.8.in
@@ -233,7 +233,8 @@ ip-link \- network device configuration
 .BR macsec " |"
 .BR netdevsim " |"
 .BR rmnet " |"
-.BR xfrm " ]"
+.BR xfrm " |"
+.BR gtp " ]"
 
 .ti -8
 .IR ETYPE " := [ " TYPE " |"
@@ -382,6 +383,9 @@ Link types:
 .sp
 .BR xfrm
 - Virtual xfrm interface
+.sp
+.BR gtp
+- GPRS Tunneling Protocol
 .in -8
 
 .TP
@@ -1926,6 +1930,29 @@ policies. Policies must be configured with the same key. If not set, the key def
 
 .in -8
 
+.TP
+GTP Type Support
+For a link of type
+.I GTP
+the following additional arguments are supported:
+
+.BI "ip link add " DEVICE " type gtp role " ROLE " hsize " HSIZE
+
+.in +8
+.sp
+.BI role " ROLE "
+- specifies the role of the GTP device, either sgsn or ggsn
+
+.sp
+.BI hsize " HSIZE "
+- specifies size of the hashtable which stores PDP contexts
+
+.sp
+.BI restart_count " RESTART_COUNT "
+- GTP instance restart counter
+
+.in -8
+
 .SS ip link delete - delete virtual link
 
 .TP
-- 
2.31.1

[PATCH iproute2-next v2 2/2] f_flower: Implement gtp options support

[Wojciech Drewek]

Add support for parsing TCA_FLOWER_KEY_ENC_OPTS_GTP.
Options are as follows: PDU_TYPE:QFI where each
option is represented as 8-bit hexadecimal value.

e.g.
  # ip link add gtp_dev type gtp role sgsn
  # tc qdisc add dev gtp_dev ingress
  # tc filter add dev gtp_dev protocol ip parent ffff: \
      flower \
        enc_key_id 11 \
        gtp_opts 1:8/ff:ff \
      action mirred egress redirect dev eth0

Signed-off-by: Wojciech Drewek <wojciech.drewek@intel.com>
---
v2: get rid of JSON specific code
---
 include/uapi/linux/pkt_cls.h |  16 +++++
 man/man8/tc-flower.8         |  10 ++++
 tc/f_flower.c                | 113 +++++++++++++++++++++++++++++++++++
 3 files changed, 139 insertions(+)

diff --git a/include/uapi/linux/pkt_cls.h b/include/uapi/linux/pkt_cls.h
index ee38b35c3f57..30ff8da0631b 100644
--- a/include/uapi/linux/pkt_cls.h
+++ b/include/uapi/linux/pkt_cls.h
@@ -616,6 +616,10 @@ enum {
 					 * TCA_FLOWER_KEY_ENC_OPT_ERSPAN_
 					 * attributes
 					 */
+	TCA_FLOWER_KEY_ENC_OPTS_GTP,	/* Nested
+					 * TCA_FLOWER_KEY_ENC_OPT_GTP_
+					 * attributes
+					 */
 	__TCA_FLOWER_KEY_ENC_OPTS_MAX,
 };
 
@@ -654,6 +658,18 @@ enum {
 #define TCA_FLOWER_KEY_ENC_OPT_ERSPAN_MAX \
 		(__TCA_FLOWER_KEY_ENC_OPT_ERSPAN_MAX - 1)
 
+enum {
+	TCA_FLOWER_KEY_ENC_OPT_GTP_UNSPEC,
+	TCA_FLOWER_KEY_ENC_OPT_GTP_PDU_TYPE,		/* u8 */
+	TCA_FLOWER_KEY_ENC_OPT_GTP_QFI,			/* u8 */
+
+	__TCA_FLOWER_KEY_ENC_OPT_GTP_MAX,
+};
+
+#define TCA_FLOWER_KEY_ENC_OPT_GTP_MAX \
+		(__TCA_FLOWER_KEY_ENC_OPT_GTP_MAX - 1)
+
+
 enum {
 	TCA_FLOWER_KEY_MPLS_OPTS_UNSPEC,
 	TCA_FLOWER_KEY_MPLS_OPTS_LSE,
diff --git a/man/man8/tc-flower.8 b/man/man8/tc-flower.8
index 4541d9372684..f918a06d2927 100644
--- a/man/man8/tc-flower.8
+++ b/man/man8/tc-flower.8
@@ -89,6 +89,8 @@ flower \- flow based traffic control filter
 .B vxlan_opts
 |
 .B erspan_opts
+|
+.B gtp_opts
 }
 .IR OPTIONS " | "
 .BR ip_flags
@@ -411,6 +413,8 @@ Match the connection zone, and can be masked.
 .BI vxlan_opts " OPTIONS"
 .TQ
 .BI erspan_opts " OPTIONS"
+.TQ
+.BI gtp_opts " OPTIONS"
 Match on IP tunnel metadata. Key id
 .I NUMBER
 is a 32 bit tunnel key id (e.g. VNI for VXLAN tunnel).
@@ -446,6 +450,12 @@ VERSION:INDEX:DIR:HWID/VERSION:INDEX_MASK:DIR_MASK:HWID_MASK, where VERSION is
 represented as a 8bit number, INDEX as an 32bit number, DIR and HWID as a 8bit
 number. Multiple options is not supported. Note INDEX/INDEX_MASK is used when
 VERSION is 1, and DIR/DIR_MASK and HWID/HWID_MASK are used when VERSION is 2.
+gtp_opts
+.I OPTIONS
+doesn't support multiple options, and it consists of a key followed by a slash
+and corresponding mask. If the mask is missing, \fBtc\fR assumes a full-length
+match. The option can be described in the form PDU_TYPE:QFI/PDU_TYPE_MASK:QFI_MASK
+where both PDU_TYPE and QFI are represented as a 8bit hexadecimal values.
 .TP
 .BI ip_flags " IP_FLAGS"
 .I IP_FLAGS
diff --git a/tc/f_flower.c b/tc/f_flower.c
index d3f79bdf4252..168ff1e5e07e 100644
--- a/tc/f_flower.c
+++ b/tc/f_flower.c
@@ -1028,6 +1028,52 @@ static int flower_parse_erspan_opt(char *str, struct nlmsghdr *n)
 	return 0;
 }
 
+static int flower_parse_gtp_opt(char *str, struct nlmsghdr *n)
+{
+	struct rtattr *nest;
+	char *token;
+	int arg, err;
+
+	nest = addattr_nest(n, MAX_MSG, TCA_FLOWER_KEY_ENC_OPTS_GTP | NLA_F_NESTED);
+
+	token = strsep(&str, ":");
+	for (arg = 1; arg <= TCA_FLOWER_KEY_ENC_OPT_GTP_MAX; arg++) {
+		switch (arg) {
+		case TCA_FLOWER_KEY_ENC_OPT_GTP_PDU_TYPE:
+		{
+			__u8 pdu_type;
+
+			if (!strlen(token))
+				break;
+			err = get_u8(&pdu_type, token, 16);
+			if (err)
+				return err;
+			addattr8(n, MAX_MSG, arg, pdu_type);
+			break;
+		}
+		case TCA_FLOWER_KEY_ENC_OPT_GTP_QFI:
+		{
+			__u8 qfi;
+
+			if (!strlen(token))
+				break;
+			err = get_u8(&qfi, token, 16);
+			if (err)
+				return err;
+			addattr8(n, MAX_MSG, arg, qfi);
+			break;
+		}
+		default:
+			fprintf(stderr, "Unknown \"gtp_opts\" type\n");
+			return -1;
+		}
+		token = strsep(&str, ":");
+	}
+	addattr_nest_end(n, nest);
+
+	return 0;
+}
+
 static int flower_parse_geneve_opts(char *str, struct nlmsghdr *n)
 {
 	char *token;
@@ -1211,6 +1257,41 @@ static int flower_parse_enc_opts_erspan(char *str, struct nlmsghdr *n)
 	return 0;
 }
 
+static int flower_parse_enc_opts_gtp(char *str, struct nlmsghdr *n)
+{
+	char key[XATTR_SIZE_MAX], mask[XATTR_SIZE_MAX];
+	struct rtattr *nest;
+	char *slash;
+	int err;
+
+	slash = strchr(str, '/');
+	if (slash) {
+		*slash++ = '\0';
+		if (strlen(slash) > XATTR_SIZE_MAX)
+			return -1;
+		strcpy(mask, slash);
+	} else
+		strcpy(mask, "ff:ff");
+
+	if (strlen(str) > XATTR_SIZE_MAX)
+		return -1;
+	strcpy(key, str);
+
+	nest = addattr_nest(n, MAX_MSG, TCA_FLOWER_KEY_ENC_OPTS | NLA_F_NESTED);
+	err = flower_parse_gtp_opt(key, n);
+	if (err)
+		return err;
+	addattr_nest_end(n, nest);
+
+	nest = addattr_nest(n, MAX_MSG, TCA_FLOWER_KEY_ENC_OPTS_MASK | NLA_F_NESTED);
+	err = flower_parse_gtp_opt(mask, n);
+	if (err)
+		return err;
+	addattr_nest_end(n, nest);
+
+	return 0;
+}
+
 static int flower_parse_mpls_lse(int *argc_p, char ***argv_p,
 				 struct nlmsghdr *nlh)
 {
@@ -1863,6 +1944,13 @@ static int flower_parse_opt(struct filter_util *qu, char *handle,
 				fprintf(stderr, "Illegal \"erspan_opts\"\n");
 				return -1;
 			}
+		} else if (matches(*argv, "gtp_opts") == 0) {
+			NEXT_ARG();
+			ret = flower_parse_enc_opts_gtp(*argv, n);
+			if (ret < 0) {
+				fprintf(stderr, "Illegal \"gtp_opts\"\n");
+				return -1;
+			}
 		} else if (matches(*argv, "action") == 0) {
 			NEXT_ARG();
 			ret = parse_action(&argc, &argv, TCA_FLOWER_ACT, n);
@@ -2332,6 +2420,21 @@ static void flower_print_erspan_opts(const char *name, struct rtattr *attr,
 	sprintf(strbuf, "%u:%u:%u:%u", ver, idx, dir, hwid);
 }
 
+static void flower_print_gtp_opts(const char *name, struct rtattr *attr,
+				  char *strbuf)
+{
+	struct rtattr *tb[TCA_FLOWER_KEY_ENC_OPT_GTP_MAX + 1];
+	__u8 pdu_type, qfi;
+
+	parse_rtattr(tb, TCA_FLOWER_KEY_ENC_OPT_GTP_MAX, RTA_DATA(attr),
+		     RTA_PAYLOAD(attr));
+
+	pdu_type = rta_getattr_u8(tb[TCA_FLOWER_KEY_ENC_OPT_GTP_PDU_TYPE]);
+	qfi = rta_getattr_u8(tb[TCA_FLOWER_KEY_ENC_OPT_GTP_QFI]);
+
+	sprintf(strbuf, "%02x:%02x", pdu_type, qfi);
+}
+
 static void __attribute__((format(printf, 2, 0)))
 flower_print_enc_parts(const char *name, const char *namefrm,
 		       struct rtattr *attr, char *key, char *mask)
@@ -2409,6 +2512,16 @@ static void flower_print_enc_opts(const char *name, struct rtattr *attr,
 
 		flower_print_enc_parts(name, "  erspan_opts %s", attr, key,
 				       msk);
+	} else if (key_tb[TCA_FLOWER_KEY_ENC_OPTS_GTP]) {
+		flower_print_gtp_opts("gtp_opt_key",
+				      key_tb[TCA_FLOWER_KEY_ENC_OPTS_GTP], key);
+
+		if (msk_tb[TCA_FLOWER_KEY_ENC_OPTS_GTP])
+			flower_print_gtp_opts("gtp_opt_mask",
+					      msk_tb[TCA_FLOWER_KEY_ENC_OPTS_GTP], msk);
+
+		flower_print_enc_parts(name, "  gtp_opts %s", attr, key,
+				       msk);
 	}
 
 	free(msk);
-- 
2.31.1

Re: [PATCH iproute2-next v2 1/2] ip: GTP support in ip link

[Stephen Hemminger]

On Fri,  4 Feb 2022 17:58:20 +0100
Wojciech Drewek <wojciech.drewek@intel.com> wrote:

> --- a/ip/iplink.c
> +++ b/ip/iplink.c
> @@ -57,7 +57,7 @@ void iplink_types_usage(void)
>  		"          macsec | macvlan | macvtap |\n"
>  		"          netdevsim | nlmon | rmnet | sit | team | team_slave |\n"
>  		"          vcan | veth | vlan | vrf | vti | vxcan | vxlan | wwan |\n"
> -		"          xfrm }\n");
> +		"          xfrm | gtp }\n");
>  }
>  

options are in alpha order, please insert in the correct place.

Re: [PATCH iproute2-next v2 2/2] f_flower: Implement gtp options support

[Stephen Hemminger]

On Fri,  4 Feb 2022 17:58:21 +0100
Wojciech Drewek <wojciech.drewek@intel.com> wrote:

> +static void flower_print_gtp_opts(const char *name, struct rtattr *attr,
> +				  char *strbuf)
> +{
> +	struct rtattr *tb[TCA_FLOWER_KEY_ENC_OPT_GTP_MAX + 1];
> +	__u8 pdu_type, qfi;
> +
> +	parse_rtattr(tb, TCA_FLOWER_KEY_ENC_OPT_GTP_MAX, RTA_DATA(attr),
> +		     RTA_PAYLOAD(attr));
> +
> +	pdu_type = rta_getattr_u8(tb[TCA_FLOWER_KEY_ENC_OPT_GTP_PDU_TYPE]);
> +	qfi = rta_getattr_u8(tb[TCA_FLOWER_KEY_ENC_OPT_GTP_QFI]);
> +
> +	sprintf(strbuf, "%02x:%02x", pdu_type, qfi);
> +}

Better to use snprintf and pass length parameter.
You are ok now, but someday this might grow.