WIP: Volte support for outgoing SIP registration

configure.ac

@@ -582,6 +582,7 @@ AST_EXT_LIB_SETUP([BEANSTALK], [Beanstalk Job Queue], [beanstalk])
 #FIXME
 AST_EXT_LIB_SETUP([VEVS], [Vocal EVS Audio Decoder/Encoder], [bluetooth])
 #AST_EXT_LIB_SETUP([VEVS], [Vocal EVS Audio Decoder/Encoder], [vocal-evs])
+AST_EXT_LIB_SETUP([LIBMNL], [MNL library], [mnl])
 
 if test "x${PBX_PJPROJECT}" != "x1" ; then
 AST_EXT_LIB_SETUP([PJPROJECT], [PJPROJECT], [pjproject])
@@ -2414,6 +2415,7 @@ AST_EXT_LIB_CHECK([BEANSTALK], [beanstalk], [bs_version], [beanstalk.h])
 
 #FIXME
 AST_EXT_LIB_CHECK([VEVS], [bluetooth], [ba2str], [bluetooth/bluetooth.h])
+AST_EXT_LIB_CHECK([LIBMNL], [mnl], [mnl_socket_open], [libmnl/libmnl.h])
 #AST_EXT_LIB_CHECK([VEVS], [vocal-evs], [vevs_enc], [vocal-evs/evs.h])
 
 PG_CONFIG=":"

include/asterisk/res_pjsip.h

@@ -563,7 +563,9 @@ enum ast_sip_auth_type {
 	/*! Google Oauth */
 	AST_SIP_AUTH_TYPE_GOOGLE_OAUTH,
 	/*! Credentials not stored this is a fake auth */
-	AST_SIP_AUTH_TYPE_ARTIFICIAL
+	AST_SIP_AUTH_TYPE_ARTIFICIAL,
+	/*! Credentials stored as a username and RES combination */
+	AST_SIP_AUTH_TYPE_IMS_AKA
 };
 
 #define SIP_SORCERY_AUTH_TYPE "auth"
@@ -586,7 +588,14 @@ struct ast_sip_auth {
 		AST_STRING_FIELD(oauth_clientid);
 		/*! Secret to use for OAuth authentication */
 		AST_STRING_FIELD(oauth_secret);
+		/*! Use USIM emulation with these parameters */
+		AST_STRING_FIELD(usim_opc);
+		AST_STRING_FIELD(usim_k);
+		AST_STRING_FIELD(usim_amf);
+		AST_STRING_FIELD(usim_sqn);
 	);
+	/*! Use AMI interface for communication with USIM (instead of emulation) */
+	unsigned int usim_ami;
 	/*! The time period (in seconds) that a nonce may be reused */
 	unsigned int nonce_lifetime;
 	/*! Used to determine what to use when authenticating */

makeopts.in

@@ -354,4 +354,7 @@ BEANSTALK_LIB=@BEANSTALK_LIB@
 VEVS_INCLUDE=@VEVS_INCLUDE@
 VEVS_LIB=@VEVS_LIB@
 
+LIBMNL_INCLUDE=@LIBMNL_INCLUDE@
+LIBMNL_LIB=@LIBMNL_LIB@
+
 HAVE_SBIN_LAUNCHD=@PBX_LAUNCHD@

res/res_pjsip/config_auth.c

@@ -63,6 +63,8 @@ static int auth_type_handler(const struct aco_option *opt, struct ast_variable *
 		ast_log(LOG_WARNING, "OAuth support is not available in the version of PJSIP in use\n");
 		return -1;
 #endif
+	} else if (!strcasecmp(var->value, "ims_aka")) {
+		auth->type = AST_SIP_AUTH_TYPE_IMS_AKA;
 	} else {
 		ast_log(LOG_WARNING, "Unknown authentication storage type '%s' specified for %s\n",
 				var->value, var->name);
@@ -74,7 +76,8 @@ static int auth_type_handler(const struct aco_option *opt, struct ast_variable *
 static const char *auth_types_map[] = {
 	[AST_SIP_AUTH_TYPE_USER_PASS] = "userpass",
 	[AST_SIP_AUTH_TYPE_MD5] = "md5",
-	[AST_SIP_AUTH_TYPE_GOOGLE_OAUTH] = "google_oauth"
+	[AST_SIP_AUTH_TYPE_GOOGLE_OAUTH] = "google_oauth",
+	[AST_SIP_AUTH_TYPE_IMS_AKA] = "ims_aka"
 };
 
 const char *ast_sip_auth_type_to_str(enum ast_sip_auth_type type)
@@ -126,6 +129,7 @@ static int auth_apply(const struct ast_sorcery *sorcery, void *obj)
 		break;
 	case AST_SIP_AUTH_TYPE_USER_PASS:
 	case AST_SIP_AUTH_TYPE_ARTIFICIAL:
+	case AST_SIP_AUTH_TYPE_IMS_AKA:
 		break;
 	}
 
@@ -395,6 +399,16 @@ int ast_sip_initialize_sorcery_auth(void)
 			"", OPT_STRINGFIELD_T, 0, STRFLDSET(struct ast_sip_auth, realm));
 	ast_sorcery_object_field_register(sorcery, SIP_SORCERY_AUTH_TYPE, "nonce_lifetime",
 			"32", OPT_UINT_T, 0, FLDSET(struct ast_sip_auth, nonce_lifetime));
+	ast_sorcery_object_field_register(sorcery, SIP_SORCERY_AUTH_TYPE, "usim_ami",
+			"no", OPT_BOOL_T, 0, FLDSET(struct ast_sip_auth, usim_ami));
+	ast_sorcery_object_field_register(sorcery, SIP_SORCERY_AUTH_TYPE, "usim_opc",
+			"", OPT_STRINGFIELD_T, 0, STRFLDSET(struct ast_sip_auth, usim_opc));
+	ast_sorcery_object_field_register(sorcery, SIP_SORCERY_AUTH_TYPE, "usim_k",
+			"", OPT_STRINGFIELD_T, 0, STRFLDSET(struct ast_sip_auth, usim_k));
+	ast_sorcery_object_field_register(sorcery, SIP_SORCERY_AUTH_TYPE, "usim_amf",
+			"", OPT_STRINGFIELD_T, 0, STRFLDSET(struct ast_sip_auth, usim_amf));
+	ast_sorcery_object_field_register(sorcery, SIP_SORCERY_AUTH_TYPE, "usim_sqn",
+			"", OPT_STRINGFIELD_T, 0, STRFLDSET(struct ast_sip_auth, usim_sqn));
 	ast_sorcery_object_field_register_custom(sorcery, SIP_SORCERY_AUTH_TYPE, "auth_type",
 			"userpass", auth_type_handler, auth_type_to_str, NULL, 0, 0);
 

res/res_pjsip_outbound_authenticator_digest.c

@@ -313,12 +313,8 @@ static pj_status_t set_outbound_authentication_credentials(pjsip_auth_clt_sess *
 		pj_cstr(&auth_cred.scheme, "digest");
 		switch (auth->type) {
 		case AST_SIP_AUTH_TYPE_USER_PASS:
-			if (volte_auth == (void *)0x1)
-				pj_cstr(&auth_cred.data, "");
-			else if (volte_auth)
-				pj_strset(&auth_cred.data, (char *)volte_auth, 8);
-			else
-				pj_cstr(&auth_cred.data, auth->auth_pass);
+		case AST_SIP_AUTH_TYPE_IMS_AKA:
+			pj_cstr(&auth_cred.data, auth->auth_pass);
 			auth_cred.data_type = PJSIP_CRED_DATA_PLAIN_PASSWD;
 			break;
 		case AST_SIP_AUTH_TYPE_MD5:

res/res_pjsip_outbound_registration.c

@@ -17,6 +17,7 @@
  */
 
 /*** MODULEINFO
+	<depend>libmnl</depend>
 	<depend>pjproject</depend>
 	<depend>res_pjsip</depend>
 	<use type="module">res_statsd</use>
@@ -213,7 +214,7 @@
 				<configOption name="user_agent">
 					<synopsis>Overrides the User-Agent header that should be used for outbound REGISTER requests.</synopsis>
 				</configOption>
-				<configOption name="volte">
+				<configOption name="ims_aka">
 					<synopsis>Perform Voice over LTE SIP registration process.</synopsis>
 				</configOption>
 			</configObject>
@@ -272,6 +273,8 @@
 /* forward declarations */
 static int set_outbound_initial_authentication_credentials(pjsip_regc *regc,
 		const struct ast_sip_auth_vector *auth_vector);
+static int add_outbound_initial_authorization(pjsip_tx_data *tdata, const char *fromdomain,
+					      const struct ast_sip_auth_vector *auth_vector);
 
 /*! \brief Some thread local storage used to determine if the running thread invoked the callback */
 AST_THREADSTORAGE(register_callback_invoked);
@@ -378,7 +381,7 @@ struct sip_outbound_registration {
 	/*! \brief Whether Outbound support is enabled */
 	unsigned int support_outbound;
 	/*! \brief VoLTE support */
-	unsigned int volte;
+	unsigned int ims_aka;
 };
 
 /*! \brief Outbound registration client state information (persists for lifetime of regc) */
@@ -447,7 +450,7 @@ struct sip_outbound_registration_client_state {
 	/*! \brief The value for the User-Agent header sent in requests */
 	char *user_agent;
 	/*! \brief VoLTE support */
-	unsigned int volte;
+	unsigned int ims_aka;
 };
 
 /*! \brief Outbound registration state information (persists for lifetime that registration should exist) */
@@ -896,6 +899,22 @@ static int handle_client_registration(void *data)
 		return -1;
 	}
 
+	/* Create initial authorization header. */
+	if (client_state->ims_aka) {
+		struct sip_outbound_registration *reg = NULL;
+		struct ast_sip_endpoint *endpt = NULL;
+		reg = ast_sorcery_retrieve_by_id(ast_sip_get_sorcery(), "registration",client_state->registration_name);
+		endpt = ast_sorcery_retrieve_by_id(ast_sip_get_sorcery(), "endpoint", reg->endpoint);
+		if ((reg = ast_sorcery_retrieve_by_id(ast_sip_get_sorcery(), "registration",
+						     client_state->registration_name)) &&
+		    reg->endpoint &&
+		    (endpt = ast_sorcery_retrieve_by_id(ast_sip_get_sorcery(), "endpoint", reg->endpoint)) &&
+		    add_outbound_initial_authorization(tdata, endpt->fromdomain, &client_state->outbound_auths)) {
+			ast_log(LOG_WARNING, "Failed to add initial authorization header.\n");
+			return -1;
+		}
+	}
+
 	registration_client_send(client_state, tdata);
 
 	return 0;
@@ -1292,6 +1311,11 @@ static int handle_registration_response(void *data)
 		pjsip_cseq_hdr *cseq_hdr;
 		pjsip_tx_data *tdata;
 
+		/* Remove initial autorization header. */
+		if (response->client_state->ims_aka) {
+			volte_del_authorization(response->old_request);
+		}
+
 		if (response->client_state->security_negotiation == AST_SIP_SECURITY_NEG_MEDIASEC) {
 			struct sip_outbound_registration *reg = NULL;
 			struct ast_sip_endpoint *endpt = NULL;
@@ -1586,7 +1610,7 @@ static struct sip_outbound_registration_state *sip_outbound_registration_state_a
 	state->client_state->registration_name =
 		ast_strdup(ast_sorcery_object_get_id(registration));
 	state->client_state->user_agent = ast_strdup(registration->user_agent);
-	state->client_state->volte = registration->volte;
+	state->client_state->ims_aka = registration->ims_aka;
 
 	ast_statsd_log_string("PJSIP.registrations.count", AST_STATSD_GAUGE, "+1", 1.0);
 	ast_statsd_log_string_va("PJSIP.registrations.state.%s", AST_STATSD_GAUGE, "+1", 1.0,
@@ -1854,6 +1878,44 @@ cleanup:
 	return res;
 }
 
+/* Add intial authorization header for IMS AKA */
+static int add_outbound_initial_authorization(pjsip_tx_data *tdata, const char *fromdomain,
+					      const struct ast_sip_auth_vector *auth_vector)
+{
+	size_t auth_size = AST_VECTOR_SIZE(auth_vector);
+	struct ast_sip_auth *auths[auth_size];
+	int res = 0;
+	int idx;
+	const char *username;
+
+puts("1");
+	memset(auths, 0, sizeof(auths));
+	if (ast_sip_retrieve_auths(auth_vector, auths)) {
+		res = -1;
+		goto cleanup;
+	}
+
+puts("2");
+	for (idx = 0; idx < auth_size; ++idx) {
+		if (auths[idx]->type == AST_SIP_AUTH_TYPE_IMS_AKA)
+			break;
+	}
+
+	if (idx == auth_size) {
+		res = -1;
+		goto cleanup;
+	}
+
+puts("3");
+	username = auths[idx]->auth_user;
+
+	volte_init_authorization(tdata, fromdomain, username);
+
+cleanup:
+	ast_sip_cleanup_auths(auths, auth_size);
+	return res;
+}
+
 /*! \brief Helper function that allocates a pjsip registration client and configures it */
 static int sip_outbound_registration_regc_alloc(void *data)
 {
@@ -2027,8 +2089,12 @@ static int sip_outbound_registration_apply(const struct ast_sorcery *sorcery, vo
 		ast_log(LOG_ERROR, "Line support has been enabled on outbound registration '%s' without providing an endpoint\n",
 			ast_sorcery_object_get_id(applied));
 		return -1;
-	} else if (!ast_strlen_zero(applied->endpoint) && !applied->line) {
-		ast_log(LOG_ERROR, "An endpoint has been specified on outbound registration '%s' without enabling line support\n",
+	} else if (applied->ims_aka && ast_strlen_zero(applied->endpoint)) {
+		ast_log(LOG_ERROR, "IMS AKA support has been enabled on outbound registration '%s' without providing an endpoint\n",
+			ast_sorcery_object_get_id(applied));
+		return -1;
+	} else if (!ast_strlen_zero(applied->endpoint) && !applied->line && !applied->ims_aka) {
+		ast_log(LOG_ERROR, "An endpoint has been specified on outbound registration '%s' without enabling line or IMS AKA support\n",
 			ast_sorcery_object_get_id(applied));
 		return -1;
 	}
@@ -2845,7 +2911,7 @@ static int load_module(void)
 	ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "line", "no", OPT_BOOL_T, 1, FLDSET(struct sip_outbound_registration, line));
 	ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "endpoint", "", OPT_STRINGFIELD_T, 0, STRFLDSET(struct sip_outbound_registration, endpoint));
 	ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "user_agent", "", OPT_STRINGFIELD_T, 0, STRFLDSET(struct sip_outbound_registration, user_agent));
-	ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "volte", "no", OPT_BOOL_T, 1, FLDSET(struct sip_outbound_registration, volte));
+	ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "ims_aka", "no", OPT_BOOL_T, 1, FLDSET(struct sip_outbound_registration, ims_aka));
 
 	/*
 	 * Register sorcery observers.

res/res_pjsip_outbound_registration/netlink_xfrm.c

@@ -0,0 +1,436 @@
+/* Linux kernel IPsec interfacing via netlink XFRM
+ *
+ * Copyright (C) 2021 Harald Welte <laforge@osmocom.org>
+ *
+ * DOUBANGO is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * DOUBANGO is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with DOUBANGO.
+ */
+
+#include <errno.h>
+#include <string.h>
+#include <stdio.h>
+#include <netinet/in.h>
+
+#include <libmnl/libmnl.h>
+#include <linux/xfrm.h>
+#include <arpa/inet.h>
+
+#include "netlink_xfrm.h"
+
+#define XFRM_USER_ID	0x240299 /* some random number; let's use TS 24.299 */
+
+struct mnl_socket *xfrm_init_mnl_socket(void)
+{
+	struct mnl_socket *mnl_socket = mnl_socket_open(NETLINK_XFRM);
+	if (!mnl_socket) {
+		fprintf(stderr, "ERR: Could not open XFRM netlink socket: %s", strerror(errno));
+		return NULL;
+	}
+
+	if (mnl_socket_bind(mnl_socket, 0, MNL_SOCKET_AUTOPID) < 0) {
+		fprintf(stderr, "ERR: Could not open XFRM netlink socket: %s", strerror(errno));
+		mnl_socket_close(mnl_socket);
+		return NULL;
+	}
+
+	return mnl_socket;
+}
+
+void xfrm_exit_mnl_socket(struct mnl_socket *mnl_socket)
+{
+	mnl_socket_close(mnl_socket);
+}
+
+static unsigned int get_next_nlmsg_seq(void)
+{
+	static unsigned int next_seq;
+	return next_seq++;
+}
+
+
+/* this is just a simple call-back which returns the nlmsghdr via 'data' */
+static int data_cb(const struct nlmsghdr *nlh, void *data)
+{
+	const struct nlmsghdr **rx = data;
+
+	*rx = nlh;
+
+	/* FIXME: is there a situation in which we'd want to return OK and not STOP? */
+	return MNL_CB_STOP;
+}
+
+/* send 'tx' via 'mnl_sock' and receive messages from kernel, using caller-provided
+ * rx_buf/rx_buf_size as temporary storage buffer; return response nlmsghdr in 'rx' */
+static int transceive_mnl(struct mnl_socket *mnl_sock, const struct nlmsghdr *tx,
+			  uint8_t *rx_buf, size_t rx_buf_size, struct nlmsghdr **rx)
+{
+	int rc;
+
+	rc = mnl_socket_sendto(mnl_sock, tx, tx->nlmsg_len);
+	if (rc < 0) {
+		fprintf(stderr, "ERR: cannot create IPsec SA: %s\n", strerror(errno));
+		return -1;
+	}
+	puts("sent");
+
+	/* iterate until it is our answer, handing to mnl_cb_run, ... */
+	while (1) {
+		rc = mnl_socket_recvfrom(mnl_sock, rx_buf, rx_buf_size);
+		if (rc == -1) {
+			perror("mnl_socket_recvfrom");
+			return -EIO;
+		}
+
+		rc = mnl_cb_run(rx_buf, rc, tx->nlmsg_seq, mnl_socket_get_portid(mnl_sock), data_cb, rx);
+		if (rc == -1) {
+			perror("mnl_cb_run");
+			return -EIO;
+		} else if (rc <= MNL_CB_STOP)
+			break;
+	}
+
+	return 0;
+}
+
+static int sockaddrs2xfrm_sel(struct xfrm_selector *sel, const struct sockaddr *src,
+			      const struct sockaddr *dst)
+{
+	const struct sockaddr_in *sin;
+	const struct sockaddr_in6 *sin6;
+
+	switch (src->sa_family) {
+	case AF_INET:
+		sin = (const struct sockaddr_in *) src;
+		sel->saddr.a4 = sin->sin_addr.s_addr;
+		sel->prefixlen_s = 32;
+		sel->sport = sin->sin_port;
+		sin = (const struct sockaddr_in *) dst;
+		sel->daddr.a4 = sin->sin_addr.s_addr;
+		sel->prefixlen_d = 32;
+		sel->dport = sin->sin_port;
+		break;
+	case AF_INET6:
+		sin6 = (const struct sockaddr_in6 *) src;
+		memcpy(sel->saddr.a6, &sin6->sin6_addr, sizeof(sel->saddr.a6));
+		sel->prefixlen_s = 128;
+		sel->sport = sin6->sin6_port;
+		sin6 = (const struct sockaddr_in6 *) dst;
+		memcpy(sel->daddr.a6, &sin6->sin6_addr, sizeof(sel->daddr.a6));
+		sel->prefixlen_d = 128;
+		sel->dport = sin6->sin6_port;
+		break;
+	default:
+		return -EINVAL;
+	}
+	sel->dport_mask = 0xffff;
+	sel->sport_mask = 0xffff;
+	sel->family = src->sa_family;
+
+	return 0;
+}
+
+
+/***********************************************************************
+ * SPI Allocation
+ ***********************************************************************/
+
+/* allocate a local SPI for ESP between given src+dst address */
+int xfrm_spi_alloc(struct mnl_socket *mnl_sock, uint32_t reqid, uint32_t *spi_out,
+		   const struct sockaddr *src, const struct sockaddr *dst)
+{
+	uint8_t msg_buf[MNL_SOCKET_BUFFER_SIZE];
+	uint8_t rx_buf[MNL_SOCKET_BUFFER_SIZE];
+	struct xfrm_userspi_info *xui, *rx_xui;
+	struct nlmsghdr *nlh, *rx_nlh = NULL;
+	const struct sockaddr_in *sin;
+	const struct sockaddr_in6 *sin6;
+	int rc;
+
+	memset(msg_buf, 0, sizeof(msg_buf));
+
+	if (src->sa_family != dst->sa_family)
+		return -EINVAL;
+
+	nlh = mnl_nlmsg_put_header(msg_buf);
+	nlh->nlmsg_flags = NLM_F_REQUEST,
+	nlh->nlmsg_type = XFRM_MSG_ALLOCSPI,
+	nlh->nlmsg_seq = get_next_nlmsg_seq();
+	//nlh->nlmsg_pid = reqid; //FIXME
+
+	xui = (struct xfrm_userspi_info *) mnl_nlmsg_put_extra_header(nlh, sizeof(*xui));
+
+	xui->info.family = src->sa_family;
+
+	/* RFC4303 reserves 0..255 */
+	xui->min = 0x100;
+	xui->max = 0xffffffff;
+
+	/* ID src, dst, proto */
+	switch (src->sa_family) {
+	case AF_INET:
+		sin = (const struct sockaddr_in *) src;
+		xui->info.saddr.a4 = sin->sin_addr.s_addr;
+		sin = (const struct sockaddr_in *) dst;
+		xui->info.id.daddr.a4 = sin->sin_addr.s_addr;
+		//xui->info.sel.prefixlen_d = 32;
+		break;
+	case AF_INET6:
+		sin6 = (const struct sockaddr_in6 *) src;
+		memcpy(xui->info.saddr.a6, &sin6->sin6_addr, sizeof(xui->info.saddr.a6));
+		//xui->info.sel.prefixlen_s = 128;
+		sin6 = (const struct sockaddr_in6 *) dst;
+		memcpy(xui->info.id.daddr.a6, &sin6->sin6_addr, sizeof(xui->info.id.daddr.a6));
+		//xui->info.sel.prefixlen_d = 128;
+		break;
+	default:
+		fprintf(stderr, "ERR: unsupported address family %u\n", src->sa_family);
+		return -1;
+	}
+
+	xui->info.id.proto = IPPROTO_ESP;
+	xui->info.reqid = reqid;
+	xui->info.mode = XFRM_MODE_TRANSPORT;
+	//xui->info.replay_window = 32; // TODO: check spec
+
+	rc = transceive_mnl(mnl_sock, nlh, rx_buf, MNL_SOCKET_BUFFER_SIZE, &rx_nlh);
+	if (rc < 0) {
+		fprintf(stderr, "ERR: cannot create IPsec SA: %s\n", strerror(errno));
+		return -1;
+	}
+
+	/* parse response */
+	rx_xui = (void *)rx_nlh + sizeof(*rx_nlh);
+	//printf("Allocated SPI=0x%08x\n", ntohl(xui->info.id.spi));
+	*spi_out = ntohl(rx_xui->info.id.spi);
+
+	return 0;
+}
+
+/***********************************************************************
+ * SA (Security Association)
+ ***********************************************************************/
+
+int xfrm_sa_del(struct mnl_socket *mnl_sock,
+		const struct sockaddr *src, const struct sockaddr *dst, uint32_t spi)
+{
+	uint8_t msg_buf[MNL_SOCKET_BUFFER_SIZE];
+	uint8_t rx_buf[MNL_SOCKET_BUFFER_SIZE];
+	struct xfrm_usersa_id *said;
+	struct nlmsghdr *nlh, *rx_nlh;
+	const struct sockaddr_in *sin;
+	const struct sockaddr_in6 *sin6;
+	xfrm_address_t saddr;
+	int rc;
+
+	memset(&saddr, 0, sizeof(saddr));
+
+	nlh = mnl_nlmsg_put_header(msg_buf);
+	nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
+	nlh->nlmsg_type = XFRM_MSG_DELSA;
+	nlh->nlmsg_seq = get_next_nlmsg_seq();
+	//nlh->nlmsg_pid = reqid; //FIXME
+
+	said = (struct xfrm_usersa_id *) mnl_nlmsg_put_extra_header(nlh, sizeof(*said));
+	said->spi = htonl(spi);
+	said->proto = IPPROTO_ESP;
+
+	said->family = src->sa_family;
+	switch (src->sa_family) {
+	case AF_INET:
+		sin = (const struct sockaddr_in *) src;
+		saddr.a4 = sin->sin_addr.s_addr;
+		sin = (const struct sockaddr_in *) dst;
+		said->daddr.a4 = sin->sin_addr.s_addr;
+		break;
+	case AF_INET6:
+		sin6 = (const struct sockaddr_in6 *) src;
+		memcpy(saddr.a6, &sin6->sin6_addr, sizeof(saddr.a6));
+		sin6 = (const struct sockaddr_in6 *) dst;
+		memcpy(said->daddr.a6, &sin6->sin6_addr, sizeof(said->daddr.a6));
+		break;
+	default:
+		fprintf(stderr, "ERR: unsupported address family %u\n", src->sa_family);
+		return -1;
+	}
+
+	mnl_attr_put(nlh, XFRMA_SRCADDR, sizeof(saddr), (void *)&saddr);
+
+	rc = transceive_mnl(mnl_sock, nlh, rx_buf, MNL_SOCKET_BUFFER_SIZE, &rx_nlh);
+	if (rc < 0) {
+		fprintf(stderr, "ERR: cannot delete IPsec SA: %s\n", strerror(errno));
+		return -1;
+	}
+
+	/* FIXME: parse response */
+
+	return 0;
+}
+
+int xfrm_sa_add(struct mnl_socket *mnl_sock, uint32_t reqid,
+		const struct sockaddr *src, const struct sockaddr *dst, uint32_t spi,
+		const struct xfrm_algo *auth_algo, const struct xfrm_algo *ciph_algo)
+{
+	uint8_t msg_buf[MNL_SOCKET_BUFFER_SIZE];
+	uint8_t rx_buf[MNL_SOCKET_BUFFER_SIZE];
+	struct xfrm_usersa_info *sainfo;
+	struct nlmsghdr *nlh, *rx_nlh;
+	int rc;
+
+	nlh = mnl_nlmsg_put_header(msg_buf);
+	nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL | NLM_F_ACK;
+	nlh->nlmsg_type = XFRM_MSG_NEWSA;
+	nlh->nlmsg_seq = get_next_nlmsg_seq();
+	//nlh->nlmsg_pid = reqid; //FIXME
+
+	sainfo = (struct xfrm_usersa_info *) mnl_nlmsg_put_extra_header(nlh, sizeof(*sainfo));
+	sainfo->sel.family = src->sa_family;
+	rc = sockaddrs2xfrm_sel(&sainfo->sel, src, dst);
+	if (rc < 0)
+		return -EINVAL;
+
+	sainfo->sel.user = htonl(XFRM_USER_ID);
+
+	sainfo->saddr = sainfo->sel.saddr;
+	sainfo->id.daddr = sainfo->sel.daddr;
+
+	sainfo->id.spi = htonl(spi);
+	sainfo->id.proto = IPPROTO_ESP;
+
+	sainfo->lft.soft_byte_limit = XFRM_INF;
+	sainfo->lft.hard_byte_limit = XFRM_INF;
+	sainfo->lft.soft_packet_limit = XFRM_INF;
+	sainfo->lft.hard_packet_limit = XFRM_INF;
+	sainfo->reqid = reqid;
+	sainfo->family = src->sa_family;
+	sainfo->mode = XFRM_MODE_TRANSPORT;
+	sainfo->replay_window = 32;
+
+	mnl_attr_put(nlh, XFRMA_ALG_AUTH, sizeof(struct xfrm_algo) + auth_algo->alg_key_len, auth_algo);
+
+	mnl_attr_put(nlh, XFRMA_ALG_CRYPT, sizeof(struct xfrm_algo) + ciph_algo->alg_key_len, ciph_algo);
+
+	rc = transceive_mnl(mnl_sock, nlh, rx_buf, MNL_SOCKET_BUFFER_SIZE, &rx_nlh);
+	if (rc < 0) {
+		fprintf(stderr, "ERR: cannot create IPsec SA: %s\n", strerror(errno));
+		return -1;
+	}
+
+	/* FIXME: parse response */
+
+	return 0;
+}
+
+/***********************************************************************
+ * Security Policy
+ ***********************************************************************/
+
+int xfrm_policy_add(struct mnl_socket *mnl_sock,
+		    const struct sockaddr *src, const struct sockaddr *dst, uint32_t spi, bool dir_in)
+{
+	uint8_t msg_buf[MNL_SOCKET_BUFFER_SIZE];
+	uint8_t rx_buf[MNL_SOCKET_BUFFER_SIZE];
+	struct xfrm_userpolicy_info *pinfo;
+	struct xfrm_user_tmpl tmpl;
+	struct nlmsghdr *nlh, *rx_nlh;
+	int rc;
+
+	memset(&tmpl, 0, sizeof(tmpl));
+
+	nlh = mnl_nlmsg_put_header(msg_buf);
+	nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL | NLM_F_ACK;
+	nlh->nlmsg_type = XFRM_MSG_NEWPOLICY;
+	nlh->nlmsg_seq = get_next_nlmsg_seq();
+	//nlh->nlmsg_pid = reqid; //FIXME
+
+	pinfo = (struct xfrm_userpolicy_info *) mnl_nlmsg_put_extra_header(nlh, sizeof(*pinfo));
+
+	rc = sockaddrs2xfrm_sel(&pinfo->sel, src, dst);
+	if (rc < 0)
+		return -EINVAL;
+
+	pinfo->sel.user = htonl(XFRM_USER_ID);
+
+	pinfo->lft.soft_byte_limit = XFRM_INF;
+	pinfo->lft.hard_byte_limit = XFRM_INF;
+	pinfo->lft.soft_packet_limit = XFRM_INF;
+	pinfo->lft.hard_packet_limit = XFRM_INF;
+	pinfo->priority = 2342; // FIXME
+	pinfo->action = XFRM_POLICY_ALLOW;
+	pinfo->share = XFRM_SHARE_ANY;
+
+	if (dir_in)
+		pinfo->dir = XFRM_POLICY_IN;
+	else
+		pinfo->dir = XFRM_POLICY_OUT;
+
+	tmpl.id.proto = IPPROTO_ESP;
+	tmpl.id.daddr = pinfo->sel.daddr;
+	tmpl.saddr = pinfo->sel.saddr;
+	tmpl.family = pinfo->sel.family;
+	tmpl.reqid = spi;
+	tmpl.mode = XFRM_MODE_TRANSPORT;
+	tmpl.aalgos = 0xffffffff;
+	tmpl.ealgos = 0xffffffff;
+	tmpl.calgos = 0xffffffff;
+	mnl_attr_put(nlh, XFRMA_TMPL, sizeof(tmpl), &tmpl);
+
+	rc = transceive_mnl(mnl_sock, nlh, rx_buf, MNL_SOCKET_BUFFER_SIZE, &rx_nlh);
+	if (rc < 0) {
+		fprintf(stderr, "ERR: cannot create IPsec policy: %s\n", strerror(errno));
+		return -1;
+	}
+
+	/* FIXME: parse response */
+
+	return 0;
+}
+
+
+int xfrm_policy_del(struct mnl_socket *mnl_sock,
+		    const struct sockaddr *src, const struct sockaddr *dst, bool dir_in)
+{
+	uint8_t msg_buf[MNL_SOCKET_BUFFER_SIZE];
+	uint8_t rx_buf[MNL_SOCKET_BUFFER_SIZE];
+	struct xfrm_userpolicy_id *pid;
+	struct nlmsghdr *nlh, *rx_nlh;
+	int rc;
+
+	nlh = mnl_nlmsg_put_header(msg_buf);
+	nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
+	nlh->nlmsg_type = XFRM_MSG_DELPOLICY;
+	nlh->nlmsg_seq = get_next_nlmsg_seq();
+	//nlh->nlmsg_pid = reqid; //FIXME
+
+	pid = (struct xfrm_userpolicy_id *) mnl_nlmsg_put_extra_header(nlh, sizeof(*pid));
+
+	rc = sockaddrs2xfrm_sel(&pid->sel, src, dst);
+	if (rc < 0)
+		return -EINVAL;
+
+	pid->sel.user = htonl(XFRM_USER_ID);
+
+	if (dir_in)
+		pid->dir = XFRM_POLICY_IN;
+	else
+		pid->dir = XFRM_POLICY_OUT;
+
+	rc = transceive_mnl(mnl_sock, nlh, rx_buf, MNL_SOCKET_BUFFER_SIZE, &rx_nlh);
+	if (rc < 0) {
+		fprintf(stderr, "ERR: cannot delete IPsec policy: %s\n", strerror(errno));
+		return -1;
+	}
+
+	/* FIXME: parse response */
+
+	return 0;
+}

res/res_pjsip_outbound_registration/netlink_xfrm.h

@@ -0,0 +1,33 @@
+#pragma once
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <sys/socket.h>
+#include <linux/xfrm.h>
+
+struct mnl_socket;
+
+struct xfrm_algobuf {
+	struct xfrm_algo algo;
+	uint8_t buf[128];
+};
+
+struct mnl_socket *xfrm_init_mnl_socket(void);
+
+void xfrm_exit_mnl_socket(struct mnl_socket *mnl_socket);
+
+int xfrm_spi_alloc(struct mnl_socket *mnl_sock, uint32_t reqid, uint32_t *spi_out,
+		   const struct sockaddr *src, const struct sockaddr *dst);
+
+int xfrm_sa_add(struct mnl_socket *mnl_sock, uint32_t reqid,
+		const struct sockaddr *src, const struct sockaddr *dst, uint32_t spi,
+		const struct xfrm_algo *auth_algo, const struct xfrm_algo *ciph_algo);
+
+int xfrm_sa_del(struct mnl_socket *mnl_sock,
+		const struct sockaddr *src, const struct sockaddr *dst, uint32_t spi);
+
+int xfrm_policy_add(struct mnl_socket *mnl_sock,
+		    const struct sockaddr *src, const struct sockaddr *dst, uint32_t spi, bool dir_in);
+
+int xfrm_policy_del(struct mnl_socket *mnl_sock,
+		    const struct sockaddr *src, const struct sockaddr *dst, bool dir_in);

res/res_pjsip_outbound_registration/volte.c

@@ -0,0 +1,425 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * (C) 2024 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+ *
+ * Author: Andreas Eversberg
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+#include "asterisk.h"
+#include "asterisk/utils.h"
+
+#include <pjsip.h>
+
+#include "volte.h"
+
+/* Socket for transform configuration */ 
+static struct mnl_socket *g_mnl_socket = NULL;
+
+/* Security address and SPI settings */
+static pj_sockaddr g_local_addr_c, g_remote_addr_s;
+static pj_sockaddr g_remote_addr_c, g_local_addr_s;
+static uint32_t g_local_spi_c, g_remote_spi_s;
+static uint32_t g_remote_spi_c, g_local_spi_s;
+static pj_bool_t g_local_sa_c_set = PJ_FALSE, g_remote_sa_s_set = PJ_FALSE;
+static pj_bool_t g_remote_sa_c_set = PJ_FALSE, g_local_sa_s_set = PJ_FALSE;
+static pj_bool_t g_local_sp_c_set = PJ_FALSE, g_remote_sp_s_set = PJ_FALSE;
+static pj_bool_t g_remote_sp_c_set = PJ_FALSE, g_local_sp_s_set = PJ_FALSE;
+
+/* Supported authentication and encryption algorithms. */
+struct ipsec_alg {
+	const char *sip_name;
+	const char *kernel_name;
+};
+
+const struct ipsec_alg ipsec_alg[] = {
+	{ "hmac-md5-96", "md5" },
+	{ "hmac-sha-1-96", "sha1" },
+	{ NULL, NULL }
+};
+
+const struct ipsec_alg ipsec_ealg[] = {
+	{ "null", "cipher_null" },
+	{ NULL, NULL }
+};
+
+/* Convert from pj_sockaddr to sockaddr_storage. */
+static void copy_pj_sockaddr_to_sockaddr_storage(const pj_sockaddr *src, struct sockaddr_storage *dst)
+{
+	memset(dst, 0, sizeof(struct sockaddr_storage));
+
+	dst->ss_family = (src->addr.sa_family == PJ_AF_INET) ? AF_INET : AF_INET6;
+
+	if (dst->ss_family == AF_INET) {
+		struct sockaddr_in *dst_in = (struct sockaddr_in *)dst;
+		const pj_sockaddr_in *src_in = (const pj_sockaddr_in *)src;
+		dst_in->sin_port = src_in->sin_port;
+		memcpy(&dst_in->sin_addr, &src_in->sin_addr, sizeof(struct in_addr));
+	} else if (dst->ss_family == AF_INET6) {
+		struct sockaddr_in6 *dst_in6 = (struct sockaddr_in6 *)dst;
+		const pj_sockaddr_in6 *src_in6 = (const pj_sockaddr_in6 *)src;
+		dst_in6->sin6_port = src_in6->sin6_port;
+		memcpy(&dst_in6->sin6_addr, &src_in6->sin6_addr, sizeof(struct in6_addr));
+	}
+}
+
+/* Convert sockaddr_storage IP to string. */
+static char *sockaddr_storage_to_string(const struct sockaddr_storage *addr, char *ip_string, size_t ip_string_len)
+{
+	if (addr->ss_family == AF_INET) {
+		const struct sockaddr_in *addr_in = (const struct sockaddr_in *)addr;
+		inet_ntop(AF_INET, &addr_in->sin_addr, ip_string, ip_string_len);
+	} else if (addr->ss_family == AF_INET6) {
+		const struct sockaddr_in6 *addr_in6 = (const struct sockaddr_in6 *)addr;
+		inet_ntop(AF_INET6, &addr_in6->sin6_addr, ip_string, ip_string_len);
+	} else {
+		snprintf(ip_string, ip_string_len, "<Unknown AF>");
+	}
+
+	return ip_string;
+}
+
+/* Delete old SA and SP entries upon new registration or module exit. */
+void volte_cleanup_xfrm(void)
+{
+	struct sockaddr_storage local_addr_c, local_addr_s;
+	struct sockaddr_storage remote_addr_c, remote_addr_s;
+
+	/* Convert from pj_sockaddr to sockaddr_storage. */
+	copy_pj_sockaddr_to_sockaddr_storage(&g_local_addr_c, &local_addr_c);
+	copy_pj_sockaddr_to_sockaddr_storage(&g_remote_addr_c, &remote_addr_c);
+	copy_pj_sockaddr_to_sockaddr_storage(&g_local_addr_s, &local_addr_s);
+	copy_pj_sockaddr_to_sockaddr_storage(&g_remote_addr_s, &remote_addr_s);
+
+	if (g_local_sa_c_set || g_local_sa_s_set || g_remote_sa_c_set || g_remote_sa_s_set ||
+	    g_local_sp_c_set || g_local_sp_s_set || g_remote_sp_c_set || g_remote_sp_s_set)
+		ast_log(LOG_DEBUG, "Remove old security associations/policies\n");
+
+	/* Remove current security associations and policies. */
+	if (g_local_sa_c_set) {
+		xfrm_sa_del(g_mnl_socket, (const struct sockaddr *)&local_addr_c,
+			    (const struct sockaddr *)&remote_addr_s, g_remote_spi_s);
+		g_local_sa_c_set = PJ_FALSE;
+	}
+	if (g_local_sa_s_set) {
+		xfrm_sa_del(g_mnl_socket, (const struct sockaddr *)&local_addr_s,
+			    (const struct sockaddr *)&remote_addr_c, g_remote_spi_c);
+		g_local_sa_s_set = PJ_FALSE;
+	}
+	if (g_remote_sa_c_set) {
+		xfrm_sa_del(g_mnl_socket, (const struct sockaddr *)&remote_addr_c,
+			    (const struct sockaddr *)&local_addr_s, g_local_spi_s);
+		g_remote_sa_c_set = PJ_FALSE;
+	}
+	if (g_remote_sa_s_set) {
+		xfrm_sa_del(g_mnl_socket, (const struct sockaddr *)&remote_addr_s,
+			    (const struct sockaddr *)&local_addr_c, g_local_spi_c);
+		g_remote_sa_s_set = PJ_FALSE;
+	}
+	if (g_local_sp_c_set) {
+		xfrm_policy_del(g_mnl_socket, (const struct sockaddr *)&local_addr_c,
+			    (const struct sockaddr *)&remote_addr_s, false);
+		g_local_sp_c_set = PJ_FALSE;
+	}
+	if (g_local_sp_s_set) {
+		xfrm_policy_del(g_mnl_socket, (const struct sockaddr *)&local_addr_s,
+			    (const struct sockaddr *)&remote_addr_c, false);
+		g_local_sp_s_set = PJ_FALSE;
+	}
+	if (g_remote_sp_c_set) {
+		xfrm_policy_del(g_mnl_socket, (const struct sockaddr *)&remote_addr_c,
+			    (const struct sockaddr *)&local_addr_s, true);
+		g_remote_sp_c_set = PJ_FALSE;
+	}
+	if (g_remote_sp_s_set) {
+		xfrm_policy_del(g_mnl_socket, (const struct sockaddr *)&remote_addr_s,
+			    (const struct sockaddr *)&local_addr_c, true);
+		g_remote_sp_s_set = PJ_FALSE;
+	}
+
+}
+
+pj_status_t volte_alloc_spi(void)
+{
+	struct sockaddr_storage local_addr_c, local_addr_s;
+	struct sockaddr_storage remote_addr_c, remote_addr_s;
+	char src_str[64], dst_str[64];
+	pj_status_t status;
+
+	/* Convert from pj_sockaddr to sockaddr_storage. */
+	copy_pj_sockaddr_to_sockaddr_storage(&g_local_addr_c, &local_addr_c);
+	copy_pj_sockaddr_to_sockaddr_storage(&g_remote_addr_c, &remote_addr_c);
+	copy_pj_sockaddr_to_sockaddr_storage(&g_local_addr_s, &local_addr_s);
+	copy_pj_sockaddr_to_sockaddr_storage(&g_remote_addr_s, &remote_addr_s);
+
+	ast_log(LOG_DEBUG, "SPI allocation: local client: %s:%d remote server: %s:%d\n",
+		sockaddr_storage_to_string(&local_addr_c, src_str, sizeof(src_str)),
+		pj_sockaddr_get_port(&g_local_addr_c),
+		sockaddr_storage_to_string(&remote_addr_s, dst_str, sizeof(dst_str)),
+		pj_sockaddr_get_port(&g_remote_addr_s));
+	ast_log(LOG_DEBUG, "SPI allocation: remote client: %s:%d local server: %s:%d\n",
+		sockaddr_storage_to_string(&remote_addr_c, src_str, sizeof(src_str)),
+		pj_sockaddr_get_port(&g_remote_addr_s),
+		sockaddr_storage_to_string(&local_addr_c, dst_str, sizeof(dst_str)),
+		pj_sockaddr_get_port(&g_local_addr_s));
+
+	/* Allocate SPI-C and SPI-S towards remote peer. */
+	status = xfrm_spi_alloc(g_mnl_socket, 2342, &g_local_spi_c, (const struct sockaddr *)&local_addr_c,
+			    (const struct sockaddr *)&remote_addr_c);
+	if (status) {
+spi_alloc_failed:
+		ast_log(LOG_ERROR, "Failed to allocate SPI.\n");
+		return status;
+	}
+	g_local_sa_s_set = PJ_TRUE;
+	status = xfrm_spi_alloc(g_mnl_socket, 2342, &g_local_spi_s, (const struct sockaddr *)&local_addr_s,
+			    (const struct sockaddr *)&remote_addr_s);
+	if (status)
+		goto spi_alloc_failed;
+	g_local_sa_c_set = PJ_TRUE;
+	ast_log(LOG_DEBUG, "SPI allocation: SPI-C=0x%08x SPI-S=0x%08x\n", g_local_spi_s, g_local_spi_c);
+
+	return PJ_TRUE;
+}
+
+/* Set new SA and SP entries upon secuirty handshake. */
+pj_status_t volte_set_xfrm(const pj_str_t *alg, const pj_str_t *ealg, uint8_t *ik)
+{
+	struct xfrm_algobuf auth_algo, ciph_algo;
+	int i, j;
+	struct sockaddr_storage local_addr_c, local_addr_s;
+	struct sockaddr_storage remote_addr_c, remote_addr_s;
+	char src_str[64], dst_str[64];
+	pj_status_t sa_add_failed = PJ_SUCCESS, sp_add_failed = PJ_SUCCESS;
+	pj_status_t status;
+
+	/* Set authentication and encryption algorithms and key. */ 
+	for (i = 0; ipsec_alg[i].sip_name; i++) {
+		if (!pj_strncmp2(alg, ipsec_alg[i].sip_name, strlen(ipsec_alg[i].sip_name)))
+			break;
+	}
+	if (!ipsec_alg[i].kernel_name) {
+		ast_log(LOG_ERROR, "Given 'alg' not supported.\n");
+		return -EINVAL;
+	}
+	for (j = 0; ipsec_ealg[j].sip_name; j++) {
+		if (!pj_strncmp2(ealg, ipsec_ealg[j].sip_name, strlen(ipsec_ealg[j].sip_name)))
+			break;
+	}
+	if (!ipsec_ealg[i].kernel_name) {
+		ast_log(LOG_ERROR, "Given 'ealg' not supported.\n");
+		return -EINVAL;
+	}
+	strcpy(auth_algo.algo.alg_name, ipsec_alg[i].kernel_name);
+	switch (i) {
+	case 0:
+		memcpy(auth_algo.algo.alg_key, ik, 16);
+		auth_algo.algo.alg_key_len = 128;
+		break;
+	case 1:
+		memcpy(auth_algo.algo.alg_key, ik, 16);
+		memset(auth_algo.algo.alg_key + 16, 0x00, 4);
+		auth_algo.algo.alg_key_len = 160;
+		break;
+	}
+	strcpy(ciph_algo.algo.alg_name, ipsec_ealg[j].kernel_name);
+	switch (j) {
+	case 0:
+		ciph_algo.algo.alg_key_len = 0;
+		break;
+	}
+
+	copy_pj_sockaddr_to_sockaddr_storage(&g_local_addr_c, &local_addr_c);
+	copy_pj_sockaddr_to_sockaddr_storage(&g_remote_addr_c, &remote_addr_c);
+	copy_pj_sockaddr_to_sockaddr_storage(&g_local_addr_s, &local_addr_s);
+	copy_pj_sockaddr_to_sockaddr_storage(&g_remote_addr_s, &remote_addr_s);
+
+	ast_log(LOG_DEBUG, "xfrm: local client: %s:%d (SPI=0x%08x) remote server: %s:%d (SPI=0x%08x)\n",
+		sockaddr_storage_to_string(&local_addr_c, src_str, sizeof(src_str)),
+		pj_sockaddr_get_port(&g_local_addr_c), g_local_spi_c,
+		sockaddr_storage_to_string(&remote_addr_s, dst_str, sizeof(dst_str)),
+		pj_sockaddr_get_port(&g_remote_addr_s), g_remote_spi_s);
+	ast_log(LOG_DEBUG, "xfrm: remote client: %s:%d (SPI=0x%08x) local server: %s:%d (SPI=0x%08x)\n",
+		sockaddr_storage_to_string(&remote_addr_c, src_str, sizeof(src_str)),
+		pj_sockaddr_get_port(&g_remote_addr_s), g_remote_spi_c,
+		sockaddr_storage_to_string(&local_addr_c, dst_str, sizeof(dst_str)),
+		pj_sockaddr_get_port(&g_local_addr_s), g_local_spi_s);
+	ast_log(LOG_DEBUG, "xfrm: alg: %s ealg: %s\n", auth_algo.algo.alg_name, ciph_algo.algo.alg_name);
+
+	status = xfrm_sa_add(g_mnl_socket, g_remote_spi_s, (const struct sockaddr *)&local_addr_c,
+			 (const struct sockaddr *)&remote_addr_s, g_remote_spi_s, &auth_algo.algo, &ciph_algo.algo);
+	if (status)
+		sa_add_failed = status;
+	else
+		g_local_sa_c_set = PJ_TRUE;
+	status = xfrm_sa_add(g_mnl_socket, g_remote_spi_c, (const struct sockaddr *)&local_addr_s,
+			 (const struct sockaddr *)&remote_addr_c, g_remote_spi_c, &auth_algo.algo, &ciph_algo.algo);
+	if (status)
+		sa_add_failed = status;
+	else
+		g_local_sa_s_set = PJ_TRUE;
+	status = xfrm_sa_add(g_mnl_socket, g_local_spi_s, (const struct sockaddr *)&remote_addr_c,
+			 (const struct sockaddr *)&local_addr_s, g_local_spi_s, &auth_algo.algo, &ciph_algo.algo);
+	if (status)
+		sa_add_failed = status;
+	else
+		g_remote_sa_c_set = PJ_TRUE;
+
+	status = xfrm_sa_add(g_mnl_socket, g_local_spi_c, (const struct sockaddr *)&remote_addr_s,
+			 (const struct sockaddr *)&local_addr_c, g_local_spi_c, &auth_algo.algo, &ciph_algo.algo);
+	if (status)
+		sa_add_failed = status;
+	else
+		g_remote_sa_s_set = PJ_TRUE;
+	status = xfrm_policy_add(g_mnl_socket, (const struct sockaddr *)&local_addr_c,
+			     (const struct sockaddr *)&remote_addr_s, g_remote_spi_s, false);
+	if (status)
+		sp_add_failed = status;
+	else
+		g_local_sp_c_set = PJ_TRUE;
+	status = xfrm_policy_add(g_mnl_socket, (const struct sockaddr *)&local_addr_s,
+			     (const struct sockaddr *)&remote_addr_c, g_remote_spi_c, false);
+	if (status)
+		sp_add_failed = status;
+	else
+		g_local_sp_s_set = PJ_TRUE;
+	status = xfrm_policy_add(g_mnl_socket, (const struct sockaddr *)&remote_addr_c,
+			     (const struct sockaddr *)&local_addr_s, g_local_spi_s, true);
+	if (status)
+		sp_add_failed = status;
+	else
+		g_remote_sp_c_set = PJ_TRUE;
+	status = xfrm_policy_add(g_mnl_socket, (const struct sockaddr *)&remote_addr_s,
+			     (const struct sockaddr *)&local_addr_c, g_local_spi_c, true);
+	if (status)
+		sp_add_failed = status;
+	else
+		g_remote_sp_s_set = PJ_TRUE;
+
+	if (sa_add_failed)
+		ast_log(LOG_ERROR, "Failed to add IPSec SA.\n");
+	if (sp_add_failed)
+		ast_log(LOG_ERROR, "Failed to add IPSec SP.\n");
+
+	return (sa_add_failed) ? sa_add_failed : sp_add_failed;
+}
+
+/* Header field names. */
+const pj_str_t STR_SUPPORTED = { "Supported", 9 };
+const pj_str_t STR_REQUIRE = { "Require", 7 };
+const pj_str_t STR_PROXY_REQUIRE = { "Proxy-Require", 13 };
+const pj_str_t STR_PATH = { "path", 4 };
+const pj_str_t STR_SEC_AGREE = { "sec-agree", 9 };
+const pj_str_t STR_AUTHORIZATION = { "Authorization", 13 };
+const pj_str_t STR_AUTS = { "auts", 4 };
+
+/* Create string header and add given value. */
+static pj_status_t add_value_string_hdr(pjsip_tx_data *tdata, const pj_str_t *name, const pj_str_t *value)
+{
+	pjsip_generic_string_hdr *hdr;
+
+	/* Add Proxy-Require header. */
+	hdr = pjsip_generic_string_hdr_create(tdata->pool, name, value);
+	if (!hdr) {
+		ast_log(LOG_ERROR, "Failed to create string header.");
+		return -ENOMEM;
+	}
+
+	/* Append header */
+	pjsip_msg_add_hdr(tdata->msg, (pjsip_hdr *)hdr);
+
+	return PJ_SUCCESS;
+}
+
+/* Add a value to an array header. If the header does not exist, it is created. */
+static pj_status_t add_value_array_hdr(pjsip_tx_data *tdata, const pj_str_t *name, const pj_str_t *value)
+{
+	pjsip_generic_array_hdr *hdr;
+	pj_bool_t created = PJ_FALSE;
+
+	/* Create header, if not yet created. */
+	hdr = pjsip_msg_find_hdr_by_name(tdata->msg, name, NULL);
+	if (!hdr) {
+		hdr = pjsip_generic_array_hdr_create(tdata->pool, name);
+		created = PJ_TRUE;
+	}
+	if (!hdr) {
+		ast_log(LOG_ERROR, "Failed to create array header.");
+		return -ENOMEM;
+	}
+	if (hdr->count == PJSIP_GENERIC_ARRAY_MAX_COUNT) {
+		ast_log(LOG_ERROR, "Too many evalue in array, skipping %s.", value->ptr);
+		return -E2BIG;
+	}
+	pj_strdup(tdata->pool, &hdr->values[hdr->count++], value);
+
+	/* Append header, if created. */
+	if (created)
+		pjsip_msg_add_hdr(tdata->msg, (pjsip_hdr *)hdr);
+
+	return PJ_SUCCESS;
+}
+
+/* Add Sec-Agree to header. */
+pj_status_t volte_add_sec_agree(pjsip_tx_data *tdata)
+{
+	pj_status_t status;
+
+	/* "Require: sec-agree" */
+	status = add_value_array_hdr(tdata, &STR_REQUIRE, &STR_SEC_AGREE);
+	if (status)
+		return status;
+	/* "Proxy-Require: sec-agree" */
+	status = add_value_string_hdr(tdata, &STR_PROXY_REQUIRE, &STR_SEC_AGREE);
+	if (status)
+		return status;
+	/* "Supported: path,sec-agree" */
+	status = add_value_array_hdr(tdata, &STR_SUPPORTED, &STR_PATH);
+	if (status)
+		return status;
+	status = add_value_array_hdr(tdata, &STR_SUPPORTED, &STR_SEC_AGREE);
+	if (status)
+		return status;
+
+	return PJ_SUCCESS;
+}
+
+/* Add initial Authorization header. */
+pj_status_t volte_init_authorization(pjsip_tx_data *tdata, const char *fromdomain, const char *username)
+{
+	char authorization[1024];
+	pj_status_t status;
+
+	snprintf(authorization, sizeof(authorization), "Digest uri=\"sip:%s\",usernmame=\"%s@%s\",response=\"\",realm=\"%s\",nonce=\"\"", fromdomain, username, fromdomain, fromdomain);
+
+	const pj_str_t authorization_str = {authorization, strlen(authorization)};
+	status = add_value_string_hdr(tdata, &STR_AUTHORIZATION, &authorization_str);
+	if (status)
+		return status;
+
+	return PJ_SUCCESS;
+}
+
+/* Remove initial Authorization header. */
+pj_status_t volte_del_authorization(pjsip_tx_data *tdata)
+{
+	pjsip_authorization_hdr *auth_hdr;
+
+	/* remove double authentication header */
+	auth_hdr = pjsip_msg_find_hdr_by_name(tdata->msg, &STR_AUTHORIZATION, NULL);
+	if (auth_hdr) {
+		pj_list_erase(auth_hdr);
+	}
+
+	return PJ_SUCCESS;
+}

res/res_pjsip_outbound_registration/volte.h

@@ -0,0 +1,11 @@
+#pragma once
+
+#include "netlink_xfrm.h"
+
+void volte_cleanup_xfrm(void);
+pj_status_t volte_alloc_spi(void);
+pj_status_t volte_set_xfrm(const pj_str_t *alg, const pj_str_t *ealg, uint8_t *ik);
+
+pj_status_t volte_add_sec_agree(pjsip_tx_data *tdata);
+pj_status_t volte_init_authorization(pjsip_tx_data *tdata, const char *fromdomain, const char *username);
+pj_status_t volte_del_authorization(pjsip_tx_data *tdata);