add libgtpnl
This patch adds the libgtpnl library. Harald mentioned that he wanted
that the specific code that is added is well encapsulated, so let's
start a small library to interact with the GTP kernel module via netlink
interface.
This was done a bit while in the rush, so the interfaces are not nice
at all and the tools need to be ported on top of this library.
This library will be used to integrate openggsn with the GTP kernel
module.
diff --git a/src/gtp-genl.c b/src/gtp-genl.c
new file mode 100644
index 0000000..0dd5473
--- /dev/null
+++ b/src/gtp-genl.c
@@ -0,0 +1,177 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <time.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <inttypes.h>
+
+#include <libmnl/libmnl.h>
+#include <linux/genetlink.h>
+
+#include <libgtpnl/gtpnl.h>
+
+#include <net/if.h>
+#include <linux/gtp_nl.h>
+
+#include "internal.h"
+
+static void gtp_build_payload(struct nlmsghdr *nlh, uint64_t tid,
+ uint32_t ifidx, uint32_t sgsn_addr,
+ uint32_t ms_addr, uint32_t version)
+{
+ mnl_attr_put_u32(nlh, GTPA_VERSION, version);
+ mnl_attr_put_u32(nlh, GTPA_LINK, ifidx);
+ mnl_attr_put_u32(nlh, GTPA_SGSN_ADDRESS, sgsn_addr);
+ mnl_attr_put_u32(nlh, GTPA_MS_ADDRESS, ms_addr);
+ mnl_attr_put_u64(nlh, GTPA_TID, tid);
+}
+
+int gtp_add_tunnel(int genl_id, struct mnl_socket *nl, const char *ifname,
+ const char *ms_addr, const char *sgsn_addr, uint64_t tid,
+ int gtp_version)
+{
+ uint32_t gtp_ifidx;
+ struct in_addr ms, sgsn;
+ struct nlmsghdr *nlh;
+ char buf[MNL_SOCKET_BUFFER_SIZE];
+ uint32_t seq = time(NULL);
+
+ gtp_ifidx = if_nametoindex(ifname);
+ if (gtp_ifidx == 0){
+ fprintf(stderr, "wrong GTP interface %s\n", ifname);
+ return -1;
+ }
+
+ if (inet_aton(ms_addr, &ms) < 0) {
+ perror("bad address for ms");
+ return -1;
+ }
+
+ if (inet_aton(sgsn_addr, &sgsn) < 0) {
+ perror("bad address for sgsn");
+ return -1;
+ }
+
+ if (gtp_version > GTP_V1) {
+ fprintf(stderr, "wrong GTP version %u, use v0 or v1\n",
+ gtp_version);
+ return -1;
+ }
+
+ nlh = genl_nlmsg_build_hdr(buf, genl_id, NLM_F_EXCL | NLM_F_ACK, ++seq,
+ GTP_CMD_TUNNEL_NEW);
+ gtp_build_payload(nlh, tid, gtp_ifidx, sgsn.s_addr,
+ ms.s_addr, gtp_version);
+
+ if (genl_socket_talk(nl, nlh, seq, NULL, NULL) < 0)
+ perror("genl_socket_talk");
+
+ return 0;
+}
+EXPORT_SYMBOL(gtp_add_tunnel);
+
+int gtp_del_tunnel(int genl_id, struct mnl_socket *nl, const char *ifname,
+ uint64_t tid, uint32_t gtp_version)
+{
+ uint32_t gtp_ifidx;
+ char buf[MNL_SOCKET_BUFFER_SIZE];
+ struct nlmsghdr *nlh;
+ uint32_t seq = time(NULL);
+
+ gtp_ifidx = if_nametoindex(ifname);
+
+ nlh = genl_nlmsg_build_hdr(buf, genl_id, NLM_F_ACK, ++seq,
+ GTP_CMD_TUNNEL_DELETE);
+ gtp_build_payload(nlh, tid, gtp_ifidx, 0, 0, gtp_version);
+
+ if (genl_socket_talk(nl, nlh, seq, NULL, NULL) < 0)
+ perror("genl_socket_talk");
+
+ return 0;
+}
+EXPORT_SYMBOL(gtp_del_tunnel);
+
+struct gtp_pdp {
+ uint32_t version;
+ uint64_t tid;
+ struct in_addr sgsn_addr;
+ struct in_addr ms_addr;
+};
+
+static int genl_gtp_validate_cb(const struct nlattr *attr, void *data)
+{
+ const struct nlattr **tb = data;
+ int type = mnl_attr_get_type(attr);
+
+ if (mnl_attr_type_valid(attr, CTRL_ATTR_MAX) < 0)
+ return MNL_CB_OK;
+
+ switch(type) {
+ case GTPA_TID:
+ if (mnl_attr_validate(attr, MNL_TYPE_U64) < 0) {
+ perror("mnl_attr_validate");
+ return MNL_CB_ERROR;
+ }
+ break;
+ case GTPA_SGSN_ADDRESS:
+ case GTPA_MS_ADDRESS:
+ case GTPA_VERSION:
+ if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {
+ perror("mnl_attr_validate");
+ return MNL_CB_ERROR;
+ }
+ break;
+ default:
+ break;
+ }
+ tb[type] = attr;
+ return MNL_CB_OK;
+}
+
+static int genl_gtp_attr_cb(const struct nlmsghdr *nlh, void *data)
+{
+ struct nlattr *tb[GTPA_MAX + 1] = {};
+ struct gtp_pdp pdp;
+ struct genlmsghdr *genl;
+
+ mnl_attr_parse(nlh, sizeof(*genl), genl_gtp_validate_cb, tb);
+ if (tb[GTPA_TID])
+ pdp.tid = mnl_attr_get_u64(tb[GTPA_TID]);
+ if (tb[GTPA_SGSN_ADDRESS]) {
+ pdp.sgsn_addr.s_addr =
+ mnl_attr_get_u32(tb[GTPA_SGSN_ADDRESS]);
+ }
+ if (tb[GTPA_MS_ADDRESS]) {
+ pdp.ms_addr.s_addr = mnl_attr_get_u32(tb[GTPA_MS_ADDRESS]);
+ }
+ if (tb[GTPA_VERSION]) {
+ pdp.version = mnl_attr_get_u32(tb[GTPA_VERSION]);
+ }
+
+ printf("version %u ", pdp.version);
+ printf("tid %"PRIu64" ms_addr %s ", pdp.tid, inet_ntoa(pdp.sgsn_addr));
+ printf("sgsn_addr %s\n", inet_ntoa(pdp.ms_addr));
+
+ return MNL_CB_OK;
+}
+
+int gtp_list_tunnel(int genl_id, struct mnl_socket *nl)
+{
+ char buf[MNL_SOCKET_BUFFER_SIZE];
+ struct nlmsghdr *nlh;
+ uint32_t seq = time(NULL);
+
+ nlh = genl_nlmsg_build_hdr(buf, genl_id, NLM_F_DUMP, 0,
+ GTP_CMD_TUNNEL_GET);
+
+ if (genl_socket_talk(nl, nlh, seq, genl_gtp_attr_cb, NULL) < 0) {
+ perror("genl_socket_talk");
+ return 0;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(gtp_list_tunnel);