Add support for SGSN role via IFLA_GTP_ROLE

This patch corresponds to a Linux kernel patch extending the kernel GTP
to also cover the SGSN role, not just the GGSN role.  In order to keep
the API/behavior compatible, gtp_dev_create() will continue to create
GGSN-side tunnels, while a new gtp_dev_create_sgsn() is introduced to
create SGSN-side tunnels.

Signed-off-by: Harald Welte <laforge@gnumonks.org>

5 files changed, 33 insertions, 4 deletions

diff --git a/include/libgtpnl/gtpnl.h b/include/libgtpnl/gtpnl.h
index 49ba03d..33bb275 100644
--- a/include/libgtpnl/gtpnl.h
+++ b/include/libgtpnl/gtpnl.h
@@ -17,6 +17,7 @@ int genl_lookup_family(struct mnl_socket *nl, const char *family);
 struct in_addr;
 
 int gtp_dev_create(int dest_ns, const char *gtp_ifname, int fd0, int fd1);
+int gtp_dev_create_sgsn(int dest_ns, const char *gtp_ifname, int fd0, int fd1);
 int gtp_dev_config(const char *iface, struct in_addr *net, uint32_t prefix);
 int gtp_dev_destroy(const char *gtp_ifname);
 
diff --git a/include/linux/if_link.h b/include/linux/if_link.h
index a3f53c9..c66ebbd 100644
--- a/include/linux/if_link.h
+++ b/include/linux/if_link.h
@@ -518,11 +518,18 @@ enum {
 #define IFLA_GENEVE_MAX	(__IFLA_GENEVE_MAX - 1)
 
 /* GTP section */
+
+enum ifla_gtp_role {
+	GTP_ROLE_GGSN = 0,
+	GTP_ROLE_SGSN,
+};
+
 enum {
 	IFLA_GTP_UNSPEC,
 	IFLA_GTP_FD0,
 	IFLA_GTP_FD1,
 	IFLA_GTP_PDP_HASHSIZE,
+	IFLA_GTP_ROLE,
 	__IFLA_GTP_MAX,
 };
 #define IFLA_GTP_MAX (__IFLA_GTP_MAX - 1)
diff --git a/src/gtp-rtnl.c b/src/gtp-rtnl.c
index 6bfec65..1dfd125 100644
--- a/src/gtp-rtnl.c
+++ b/src/gtp-rtnl.c
@@ -105,7 +105,8 @@ static int gtp_dev_talk(struct nlmsghdr *nlh, uint32_t seq)
 	return ret;
 }
 
-int gtp_dev_create(int dest_ns, const char *gtp_ifname, int fd0, int fd1)
+static int _gtp_dev_create(int dest_ns, const char *gtp_ifname, int fd0,
+			   int fd1, enum ifla_gtp_role role)
 {
 	char buf[MNL_SOCKET_BUFFER_SIZE];
 	struct nlmsghdr *nlh;
@@ -129,13 +130,26 @@ int gtp_dev_create(int dest_ns, const char *gtp_ifname, int fd0, int fd1)
 	mnl_attr_put_u32(nlh, IFLA_GTP_FD0, fd0);
 	mnl_attr_put_u32(nlh, IFLA_GTP_FD1, fd1);
 	mnl_attr_put_u32(nlh, IFLA_GTP_PDP_HASHSIZE, 131072);
+	if (role != GTP_ROLE_GGSN)
+		mnl_attr_put_u32(nlh, IFLA_GTP_ROLE, role);
 	mnl_attr_nest_end(nlh, nest2);
 	mnl_attr_nest_end(nlh, nest);
 
 	return gtp_dev_talk(nlh, seq);
 }
+
+int gtp_dev_create(int dest_ns, const char *gtp_ifname, int fd0, int fd1)
+{
+	return _gtp_dev_create(dest_ns, gtp_ifname, fd0, fd1, GTP_ROLE_GGSN);
+}
 EXPORT_SYMBOL(gtp_dev_create);
 
+int gtp_dev_create_sgsn(int dest_ns, const char *gtp_ifname, int fd0, int fd1)
+{
+	return _gtp_dev_create(dest_ns, gtp_ifname, fd0, fd1, GTP_ROLE_SGSN);
+}
+EXPORT_SYMBOL(gtp_dev_create_sgsn);
+
 int gtp_dev_destroy(const char *gtp_ifname)
 {
 	char buf[MNL_SOCKET_BUFFER_SIZE];
diff --git a/src/libgtpnl.map b/src/libgtpnl.map
index 9ca83c7..9ce465d 100644
--- a/src/libgtpnl.map
+++ b/src/libgtpnl.map
@@ -6,6 +6,7 @@ global:
   genl_lookup_family;
 
   gtp_dev_create;
+  gtp_dev_create_sgsn;
   gtp_dev_config;
   gtp_dev_destroy;
 
diff --git a/tools/gtp-link.c b/tools/gtp-link.c
index 97dfa45..8367c6e 100644
--- a/tools/gtp-link.c
+++ b/tools/gtp-link.c
@@ -43,9 +43,9 @@
 int main(int argc, char *argv[])
 {
 	char buf[MNL_SOCKET_BUFFER_SIZE];
-	int ret;
+	int ret, sgsn_mode = 0;
 
-	if (argc != 3) {
+	if (argc < 3) {
 		printf("Usage: %s <add|del> <device>\n", argv[0]);
 		exit(EXIT_FAILURE);
 	}
@@ -58,6 +58,9 @@ int main(int argc, char *argv[])
 		return 0;
 	}
 
+	if (argc > 3 && !strcmp(argv[3], "--sgsn"))
+		sgsn_mode = 1;
+
 	int fd1 = socket(AF_INET, SOCK_DGRAM, 0);
 	int fd2 = socket(AF_INET, SOCK_DGRAM, 0);
 	struct sockaddr_in sockaddr_fd1 = {
@@ -86,7 +89,10 @@ int main(int argc, char *argv[])
 		exit(EXIT_FAILURE);
 	}
 
-	ret = gtp_dev_create(-1, argv[2], fd1, fd2);
+	if (sgsn_mode)
+		ret = gtp_dev_create_sgsn(-1, argv[2], fd1, fd2);
+	else
+		ret = gtp_dev_create(-1, argv[2], fd1, fd2);
 	if (ret < 0) {
 		perror("cannot create GTP device\n");
 		exit(EXIT_FAILURE);