Move kernel GTP support from ggsn/ to lib/

This way, the IP address / route handling between TUN devices and kernel
GTP can be shared, which will provide not only a unified codebase but
also a more consistent behavior.

This also paves the road for to use kernel GTP from sgsnemu in the future.

Related: OS#3214
Change-Id: Ic53a971136edd0d8871fbd6746d7b0090ce3a188

4 files changed, 74 insertions, 306 deletions

diff --git a/ggsn/Makefile.am b/ggsn/Makefile.am
index 6b2232f..eca385f 100644
--- a/ggsn/Makefile.am
+++ b/ggsn/Makefile.am
@@ -12,8 +12,4 @@ osmo_ggsn_LDADD += $(LIBGTPNL_LIBS)
 endif
 
 osmo_ggsn_DEPENDENCIES = ../gtp/libgtp.la ../lib/libmisc.a
-osmo_ggsn_SOURCES = ggsn_vty.c ggsn.c ggsn.h gtp-kernel.h icmpv6.c icmpv6.h checksum.c checksum.h
-
-if ENABLE_GTP_KERNEL
-osmo_ggsn_SOURCES += gtp-kernel.c
-endif
+osmo_ggsn_SOURCES = ggsn_vty.c ggsn.c ggsn.h icmpv6.c icmpv6.h checksum.c checksum.h
diff --git a/ggsn/ggsn.c b/ggsn/ggsn.c
index 85a2211..2b0581e 100644
--- a/ggsn/ggsn.c
+++ b/ggsn/ggsn.c
@@ -63,9 +63,9 @@
 #include "../lib/ippool.h"
 #include "../lib/syserr.h"
 #include "../lib/in46_addr.h"
+#include "../lib/gtp-kernel.h"
 #include "../gtp/pdp.h"
 #include "../gtp/gtp.h"
-#include "gtp-kernel.h"
 #include "icmpv6.h"
 #include "ggsn.h"
 
@@ -125,13 +125,14 @@ int apn_stop(struct apn_ctx *apn, bool force)
 			LOGPAPN( LOGL_INFO, apn, "Running %s\n", apn->tun.cfg.ipdown_script);
 			tun_runscript(apn->tun.tun, apn->tun.cfg.ipdown_script);
 		}
-		/* release tun device */
-		LOGPAPN(LOGL_INFO, apn, "Closing TUN device %s\n", apn->tun.tun->devname);
-		osmo_fd_unregister(&apn->tun.fd);
+		if (apn->cfg.gtpu_mode == APN_GTPU_MODE_TUN) {
+			/* release tun device */
+			LOGPAPN(LOGL_INFO, apn, "Closing TUN device %s\n", apn->tun.tun->devname);
+			osmo_fd_unregister(&apn->tun.fd);
+		}
 		tun_free(apn->tun.tun);
 		apn->tun.tun = NULL;
 	}
-	gtp_kernel_stop(apn->tun.cfg.dev_name);
 
 	if (apn->v4.pool) {
 		LOGPAPN(LOGL_INFO, apn, "Releasing IPv4 pool\n");
@@ -195,6 +196,7 @@ int apn_start(struct apn_ctx *apn)
 	struct in46_prefix ipv6_tun_linklocal_ip;
 	struct in46_prefix *blacklist;
 	int blacklist_size;
+	struct gsn_t *gsn = apn->ggsn->gsn;
 	int rc;
 
 	if (apn->started)
@@ -204,7 +206,7 @@ int apn_start(struct apn_ctx *apn)
 	switch (apn->cfg.gtpu_mode) {
 	case APN_GTPU_MODE_TUN:
 		LOGPAPN(LOGL_INFO, apn, "Opening TUN device %s\n", apn->tun.cfg.dev_name);
-		if (tun_new(&apn->tun.tun, apn->tun.cfg.dev_name)) {
+		if (tun_new(&apn->tun.tun, apn->tun.cfg.dev_name, -1, -1, false)) {
 			LOGPAPN(LOGL_ERROR, apn, "Failed to configure tun device\n");
 			return -1;
 		}
@@ -216,66 +218,6 @@ int apn_start(struct apn_ctx *apn)
 
 		/* Set TUN library callback */
 		tun_set_cb_ind(apn->tun.tun, cb_tun_ind);
-
-		if (apn->v4.cfg.ifconfig_prefix.addr.len) {
-			LOGPAPN(LOGL_INFO, apn, "Setting tun IP address %s\n",
-				in46p_ntoa(&apn->v4.cfg.ifconfig_prefix));
-			if (tun_addaddr(apn->tun.tun, &apn->v4.cfg.ifconfig_prefix.addr, NULL,
-					apn->v4.cfg.ifconfig_prefix.prefixlen)) {
-				LOGPAPN(LOGL_ERROR, apn, "Failed to set tun IPv4 address %s: %s\n",
-					in46p_ntoa(&apn->v4.cfg.ifconfig_prefix), strerror(errno));
-				apn_stop(apn, false);
-				return -1;
-			}
-		}
-
-		if (apn->v6.cfg.ifconfig_prefix.addr.len) {
-			LOGPAPN(LOGL_INFO, apn, "Setting tun IPv6 address %s\n",
-				in46p_ntoa(&apn->v6.cfg.ifconfig_prefix));
-			if (tun_addaddr(apn->tun.tun, &apn->v6.cfg.ifconfig_prefix.addr, NULL,
-					apn->v6.cfg.ifconfig_prefix.prefixlen)) {
-				LOGPAPN(LOGL_ERROR, apn, "Failed to set tun IPv6 address %s: %s. "
-					"Ensure you have ipv6 support and not used the disable_ipv6 sysctl?\n",
-					in46p_ntoa(&apn->v6.cfg.ifconfig_prefix), strerror(errno));
-				apn_stop(apn, false);
-				return -1;
-			}
-		}
-
-		if (apn->v6.cfg.ll_prefix.addr.len) {
-			LOGPAPN(LOGL_INFO, apn, "Setting tun IPv6 link-local address %s\n",
-				in46p_ntoa(&apn->v6.cfg.ll_prefix));
-			if (tun_addaddr(apn->tun.tun, &apn->v6.cfg.ll_prefix.addr, NULL,
-					apn->v6.cfg.ll_prefix.prefixlen)) {
-				LOGPAPN(LOGL_ERROR, apn, "Failed to set tun IPv6 link-local address %s: %s. "
-					"Ensure you have ipv6 support and not used the disable_ipv6 sysctl?\n",
-					in46p_ntoa(&apn->v6.cfg.ll_prefix), strerror(errno));
-				apn_stop(apn, false);
-				return -1;
-			}
-			apn->v6_lladdr = apn->v6.cfg.ll_prefix.addr.v6;
-		}
-
-		if (apn->tun.cfg.ipup_script) {
-			LOGPAPN(LOGL_INFO, apn, "Running ip-up script %s\n",
-				apn->tun.cfg.ipup_script);
-			tun_runscript(apn->tun.tun, apn->tun.cfg.ipup_script);
-		}
-
-		if (apn->cfg.apn_type_mask & (APN_TYPE_IPv6|APN_TYPE_IPv4v6) &&
-		    apn->v6.cfg.ll_prefix.addr.len == 0) {
-			rc = tun_ip_local_get(apn->tun.tun, &ipv6_tun_linklocal_ip, 1, IP_TYPE_IPv6_LINK);
-			if (rc < 1) {
-				LOGPAPN(LOGL_ERROR, apn, "Cannot obtain IPv6 link-local address of interface: %s\n",
-					rc ? strerror(errno) : "tun interface has no link-local IP assigned");
-				apn_stop(apn, false);
-				return -1;
-			}
-			apn->v6_lladdr = ipv6_tun_linklocal_ip.addr.v6;
-		}
-
-		/* set back-pointer from TUN device to APN */
-		apn->tun.tun->priv = apn;
 		break;
 	case APN_GTPU_MODE_KERNEL_GTP:
 		LOGPAPN(LOGL_INFO, apn, "Opening Kernel GTP device %s\n", apn->tun.cfg.dev_name);
@@ -284,7 +226,7 @@ int apn_start(struct apn_ctx *apn)
 			apn_stop(apn, false);
 			return -1;
 		}
-		if (apn->ggsn->gsn == NULL) {
+		if (gsn == NULL) {
 			/* skip bringing up the APN now if the GSN is not initialized yet.
 			 * This happens during initial load of the config file, as the
 			 * "no shutdown" in the ggsn node only happens after the "apn" nodes
@@ -293,8 +235,8 @@ int apn_start(struct apn_ctx *apn)
 			return 0;
 		}
 		/* use GTP kernel module for data packet encapsulation */
-		if (gtp_kernel_init(apn->ggsn->gsn, apn->tun.cfg.dev_name,
-				    &apn->v4.cfg.ifconfig_prefix, apn->tun.cfg.ipup_script) < 0) {
+		if (tun_new(&apn->tun.tun, apn->tun.cfg.dev_name, gsn->fd0, gsn->fd1u, true)) {
+			LOGPAPN(LOGL_ERROR, apn, "Failed to configure Kernel GTP device\n");
 			return -1;
 		}
 		break;
@@ -303,6 +245,68 @@ int apn_start(struct apn_ctx *apn)
 		return -1;
 	}
 
+	/* common initialization below */
+
+	/* set back-pointer from TUN device to APN */
+	apn->tun.tun->priv = apn;
+
+	if (apn->v4.cfg.ifconfig_prefix.addr.len) {
+		LOGPAPN(LOGL_INFO, apn, "Setting tun IP address %s\n",
+			in46p_ntoa(&apn->v4.cfg.ifconfig_prefix));
+		if (tun_addaddr(apn->tun.tun, &apn->v4.cfg.ifconfig_prefix.addr, NULL,
+				apn->v4.cfg.ifconfig_prefix.prefixlen)) {
+			LOGPAPN(LOGL_ERROR, apn, "Failed to set tun IPv4 address %s: %s\n",
+				in46p_ntoa(&apn->v4.cfg.ifconfig_prefix), strerror(errno));
+			apn_stop(apn, false);
+			return -1;
+		}
+	}
+
+	if (apn->v6.cfg.ifconfig_prefix.addr.len) {
+		LOGPAPN(LOGL_INFO, apn, "Setting tun IPv6 address %s\n",
+			in46p_ntoa(&apn->v6.cfg.ifconfig_prefix));
+		if (tun_addaddr(apn->tun.tun, &apn->v6.cfg.ifconfig_prefix.addr, NULL,
+				apn->v6.cfg.ifconfig_prefix.prefixlen)) {
+			LOGPAPN(LOGL_ERROR, apn, "Failed to set tun IPv6 address %s: %s. "
+				"Ensure you have ipv6 support and not used the disable_ipv6 sysctl?\n",
+				in46p_ntoa(&apn->v6.cfg.ifconfig_prefix), strerror(errno));
+			apn_stop(apn, false);
+			return -1;
+		}
+	}
+
+	if (apn->v6.cfg.ll_prefix.addr.len) {
+		LOGPAPN(LOGL_INFO, apn, "Setting tun IPv6 link-local address %s\n",
+			in46p_ntoa(&apn->v6.cfg.ll_prefix));
+		if (tun_addaddr(apn->tun.tun, &apn->v6.cfg.ll_prefix.addr, NULL,
+				apn->v6.cfg.ll_prefix.prefixlen)) {
+			LOGPAPN(LOGL_ERROR, apn, "Failed to set tun IPv6 link-local address %s: %s. "
+				"Ensure you have ipv6 support and not used the disable_ipv6 sysctl?\n",
+				in46p_ntoa(&apn->v6.cfg.ll_prefix), strerror(errno));
+			apn_stop(apn, false);
+			return -1;
+		}
+		apn->v6_lladdr = apn->v6.cfg.ll_prefix.addr.v6;
+	}
+
+	if (apn->tun.cfg.ipup_script) {
+		LOGPAPN(LOGL_INFO, apn, "Running ip-up script %s\n",
+			apn->tun.cfg.ipup_script);
+		tun_runscript(apn->tun.tun, apn->tun.cfg.ipup_script);
+	}
+
+	if (apn->cfg.apn_type_mask & (APN_TYPE_IPv6|APN_TYPE_IPv4v6) &&
+	    apn->v6.cfg.ll_prefix.addr.len == 0) {
+		rc = tun_ip_local_get(apn->tun.tun, &ipv6_tun_linklocal_ip, 1, IP_TYPE_IPv6_LINK);
+		if (rc < 1) {
+			LOGPAPN(LOGL_ERROR, apn, "Cannot obtain IPv6 link-local address of interface: %s\n",
+				rc ? strerror(errno) : "tun interface has no link-local IP assigned");
+			apn_stop(apn, false);
+			return -1;
+		}
+		apn->v6_lladdr = ipv6_tun_linklocal_ip.addr.v6;
+	}
+
 	/* Create IPv4 pool */
 	if (apn->v4.cfg.dynamic_prefix.addr.len) {
 		LOGPAPN(LOGL_INFO, apn, "Creating IPv4 pool %s\n",
diff --git a/ggsn/gtp-kernel.c b/ggsn/gtp-kernel.c
deleted file mode 100644
index 4564d9a..0000000
--- a/ggsn/gtp-kernel.c
+++ /dev/null
@@ -1,196 +0,0 @@
-#ifdef __linux__
-#define _GNU_SOURCE 1		/* strdup() prototype, broken arpa/inet.h */
-#endif
-
-#include "../config.h"
-
-#ifdef HAVE_STDINT_H
-#include <stdint.h>
-#endif
-
-#include <stdio.h>
-#include <string.h>
-#include <stdlib.h>
-#include <inttypes.h>
-#include <sys/types.h>
-#include <arpa/inet.h>
-#include <net/if.h>
-
-#include <libgtpnl/gtp.h>
-#include <libgtpnl/gtpnl.h>
-#include <libmnl/libmnl.h>
-
-#include <errno.h>
-
-#include <time.h>
-
-#include "../lib/tun.h"
-#include "../lib/syserr.h"
-#include "../gtp/pdp.h"
-#include "../gtp/gtp.h"
-
-#include <libgtpnl/gtp.h>
-#include <libgtpnl/gtpnl.h>
-#include <libmnl/libmnl.h>
-
-#include "gtp-kernel.h"
-
-static void pdp_debug(const char *prefix, const char *devname, struct pdp_t *pdp)
-{
-	struct in46_addr ia46;
-	struct in_addr ia;
-
-	in46a_from_eua(&pdp->eua, &ia46);
-	gsna2in_addr(&ia, &pdp->gsnrc);
-
-	LOGPDPX(DGGSN, LOGL_DEBUG, pdp, "%s %s v%u TEID %"PRIx64" EUA=%s SGSN=%s\n", prefix,
-		devname, pdp->version,
-		pdp->version == 0 ? pdp_gettid(pdp->imsi, pdp->nsapi) : pdp->teid_gn,
-		in46a_ntoa(&ia46), inet_ntoa(ia));
-}
-
-static struct {
-	int			genl_id;
-	struct mnl_socket	*nl;
-} gtp_nl;
-
-static int gtp_kernel_init_once(void)
-{
-	/* only initialize once */
-	if (gtp_nl.nl)
-		return 0;
-
-	gtp_nl.nl = genl_socket_open();
-	if (gtp_nl.nl == NULL) {
-		LOGP(DGGSN, LOGL_ERROR, "cannot create genetlink socket\n");
-		return -1;
-	}
-	gtp_nl.genl_id = genl_lookup_family(gtp_nl.nl, "gtp");
-	if (gtp_nl.genl_id < 0) {
-		LOGP(DGGSN, LOGL_ERROR, "cannot lookup GTP genetlink ID\n");
-		genl_socket_close(gtp_nl.nl);
-		gtp_nl.nl = NULL;
-		return -1;
-	}
-	LOGP(DGGSN, LOGL_NOTICE, "Initialized GTP kernel mode (genl ID is %d)\n", gtp_nl.genl_id);
-
-	return 0;
-}
-
-int gtp_kernel_init(struct gsn_t *gsn, const char *devname, struct in46_prefix *prefix, const char *ipup)
-{
-	struct in_addr net;
-	const char *net_arg;
-
-	if (!gtp_nl.nl)
-		gtp_kernel_init_once();
-
-	if (prefix->addr.len != 4) {
-		LOGP(DGGSN, LOGL_ERROR, "we only support IPv4 in this path :/");
-		return -1;
-	}
-	net = prefix->addr.v4;
-
-	if (gtp_dev_create(-1, devname, gsn->fd0, gsn->fd1u) < 0) {
-		LOGP(DGGSN, LOGL_ERROR, "cannot create GTP tunnel device: %s\n",
-			strerror(errno));
-		return -1;
-	}
-
-	net_arg = in46p_ntoa(prefix);
-
-	DEBUGP(DGGSN, "Setting route to reach %s via %s\n", net_arg, devname);
-
-	if (gtp_dev_config(devname, &net, prefix->prefixlen) < 0) {
-		LOGP(DGGSN, LOGL_ERROR, "Cannot add route to reach network %s\n", net_arg);
-	}
-
-	/* launch script if it is set to bring up the route to reach
-	 * the MS, eg. ip ro add 10.0.0.0/8 dev gtp0. Better add this
-	 * using native rtnetlink interface given that we know the
-	 * MS network mask, later.
-	 */
-	if (ipup) {
-		char cmd[1024];
-		int err;
-
-		/* eg. /home/ggsn/ipup gtp0 10.0.0.0/8 */
-		snprintf(cmd, sizeof(cmd), "%s %s %s", ipup, devname, net_arg);
-		cmd[sizeof(cmd)-1] = '\0';
-
-		err = system(cmd);
-		if (err < 0) {
-			LOGP(DGGSN, LOGL_ERROR, "Failed to launch script `%s'\n", ipup);
-			return -1;
-		}
-	}
-	LOGP(DGGSN, LOGL_NOTICE, "GTP kernel configured\n");
-
-	return 0;
-}
-
-void gtp_kernel_stop(const char *devname)
-{
-	gtp_dev_destroy(devname);
-}
-
-int gtp_kernel_tunnel_add(struct pdp_t *pdp, const char *devname)
-{
-	struct in_addr ms, sgsn;
-	struct gtp_tunnel *t;
-	int ret;
-
-	pdp_debug(__func__, devname, pdp);
-
-	t = gtp_tunnel_alloc();
-	if (t == NULL)
-		return -1;
-
-	memcpy(&ms, &pdp->eua.v[2], sizeof(struct in_addr));
-	memcpy(&sgsn, &pdp->gsnrc.v[0], sizeof(struct in_addr));
-
-	gtp_tunnel_set_ifidx(t, if_nametoindex(devname));
-	gtp_tunnel_set_version(t, pdp->version);
-	gtp_tunnel_set_ms_ip4(t, &ms);
-	gtp_tunnel_set_sgsn_ip4(t, &sgsn);
-	if (pdp->version == 0) {
-		gtp_tunnel_set_tid(t, pdp_gettid(pdp->imsi, pdp->nsapi));
-		gtp_tunnel_set_flowid(t, pdp->flru);
-	} else {
-		gtp_tunnel_set_i_tei(t, pdp->teid_own);
-		/* use the TEI advertised by SGSN when sending packets
-		 * towards the SGSN */
-		gtp_tunnel_set_o_tei(t, pdp->teid_gn);
-	}
-
-	ret = gtp_add_tunnel(gtp_nl.genl_id, gtp_nl.nl, t);
-	gtp_tunnel_free(t);
-
-	return ret;
-}
-
-int gtp_kernel_tunnel_del(struct pdp_t *pdp, const char *devname)
-{
-	struct gtp_tunnel *t;
-	int ret;
-
-	pdp_debug(__func__, devname, pdp);
-
-	t = gtp_tunnel_alloc();
-	if (t == NULL)
-		return -1;
-
-	gtp_tunnel_set_ifidx(t, if_nametoindex(devname));
-	gtp_tunnel_set_version(t, pdp->version);
-	if (pdp->version == 0) {
-		gtp_tunnel_set_tid(t, pdp_gettid(pdp->imsi, pdp->nsapi));
-		gtp_tunnel_set_flowid(t, pdp->flru);
-	} else {
-		gtp_tunnel_set_i_tei(t, pdp->teid_own);
-	}
-
-	ret = gtp_del_tunnel(gtp_nl.genl_id, gtp_nl.nl, t);
-	gtp_tunnel_free(t);
-
-	return ret;
-}
diff --git a/ggsn/gtp-kernel.h b/ggsn/gtp-kernel.h
deleted file mode 100644
index e2da55a..0000000
--- a/ggsn/gtp-kernel.h
+++ /dev/null
@@ -1,36 +0,0 @@
-#ifndef _GTP_KERNEL_H_
-#define _GTP_KERNEL_H_
-
-struct gengetopt_args_info;
-
-extern int debug;
-extern char *ipup;
-
-#ifdef GTP_KERNEL
-int gtp_kernel_init(struct gsn_t *gsn, const char *devname, struct in46_prefix *prefix, const char *ipup);
-void gtp_kernel_stop(const char *devname);
-
-int gtp_kernel_tunnel_add(struct pdp_t *pdp, const char *devname);
-int gtp_kernel_tunnel_del(struct pdp_t *pdp, const char *devname);
-
-#else
-static inline int gtp_kernel_init(struct gsn_t *gsn, const char *devname, struct in46_prefix *prefix, const char *ipup)
-{
-	SYS_ERR(DGGSN, LOGL_ERROR, 0, "ggsn compiled without GTP kernel support!\n");
-	return -1;
-}
-
-static inline void gtp_kernel_stop(const char *devname) {}
-
-static inline int gtp_kernel_tunnel_add(struct pdp_t *pdp, const char *devname)
-{
-	return 0;
-}
-
-static inline int gtp_kernel_tunnel_del(struct pdp_t *pdp, const char *devname)
-{
-	return 0;
-}
-
-#endif
-#endif /* _GTP_KERNEL_H_ */