ipoe: add dhcp link selection sub-option

Add the support of DHCP option 82 "Agent Information" sub-option 5
"link selection". The IPv4 value can be specified in the [ipoe]
"link-selection" configuration option.

Link: https://www.rfc-editor.org/rfc/rfc3527.html
Signed-off-by: Philippe Guibert <philippe.guibert@6wind.com>
Signed-off-by: Louis Scalbert <louis.scalbert@6wind.com>

4 files changed, 101 insertions, 30 deletions

diff --git a/accel-pppd/ctrl/ipoe/dhcpv4.c b/accel-pppd/ctrl/ipoe/dhcpv4.c
index 5218a73..466dfee 100644
--- a/accel-pppd/ctrl/ipoe/dhcpv4.c
+++ b/accel-pppd/ctrl/ipoe/dhcpv4.c
@@ -430,7 +430,7 @@ void dhcpv4_packet_free(struct dhcpv4_packet *pack)
 	mempool_free(pack);
 }
 
-int dhcpv4_parse_opt82(struct dhcpv4_option *opt, uint8_t **agent_circuit_id, uint8_t **agent_remote_id)
+int dhcpv4_parse_opt82(struct dhcpv4_option *opt, uint8_t **agent_circuit_id, uint8_t **agent_remote_id, uint8_t **link_selection)
 {
 	uint8_t *ptr = opt->data;
 	uint8_t *endptr = ptr + opt->len;
@@ -450,6 +450,8 @@ int dhcpv4_parse_opt82(struct dhcpv4_option *opt, uint8_t **agent_circuit_id, ui
 			*agent_circuit_id = ptr - 1;
 		else if (type == 2)
 			*agent_remote_id = ptr - 1;
+		else if (type == 5)
+			*link_selection = ptr - 1;
 
 		ptr += len;
 	}
@@ -457,25 +459,51 @@ int dhcpv4_parse_opt82(struct dhcpv4_option *opt, uint8_t **agent_circuit_id, ui
 	return 0;
 }
 
-int dhcpv4_packet_insert_opt82(struct dhcpv4_packet *pack, const char *agent_circuit_id, const char *agent_remote_id)
+int dhcpv4_packet_insert_opt82(struct dhcpv4_packet *pack, const char *agent_circuit_id, const char *agent_remote_id, const char *link_selection)
 {
 	int len1 = strlen(agent_circuit_id);
-	int len2 = strlen(agent_remote_id);
-	uint8_t *data = _malloc(4 + len1 + len2);
-	uint8_t *ptr = data;
+	int len2 = 0;
+	int len5 = 0;
+	int opt82_len;
+	uint8_t *data;
+	uint8_t *ptr;
 	int r;
+	struct in_addr link_select = {0};
 
 	pack->ptr--;
 
-	*ptr++ = 1;
+	opt82_len = len1 + 2;
+	if (agent_remote_id) {
+		len2 = strlen(agent_remote_id);
+		opt82_len += len2 + 2;
+	}
+	if (link_selection && inet_pton(AF_INET, link_selection, &link_select) > 0) {
+		len5 = sizeof(struct in_addr);
+		opt82_len += len5 + 2;
+	}
+
+	data = _malloc(opt82_len);
+	ptr = data;
+
+	/* Agent Circuit ID */
+	*ptr++ = 1; /* Sub-Option 1 */
 	*ptr++ = len1;
 	memcpy(ptr, agent_circuit_id, len1); ptr += len1;
 
-	*ptr++ = 2;
-	*ptr++ = len2;
-	memcpy(ptr, agent_remote_id, len2); ptr += len2;
+	/* Agent Remote ID */
+	if (len2 > 0) {
+		*ptr++ = 2; /* Sub-Option 2 */
+		*ptr++ = len2;
+		memcpy(ptr, agent_remote_id, len2); ptr += len2;
+	}
+	/* Link-Selection */
+	if (len5 > 0) {
+		*ptr++ = 5; /* Sub-Option 5 */
+		*ptr++ = len5;
+		memcpy(ptr, &link_select, len5); ptr += len5;
+	}
 
-	r = dhcpv4_packet_add_opt(pack, 82, data, 4 + len1 + len2);
+	r = dhcpv4_packet_add_opt(pack, 82, data, opt82_len);
 	_free(data);
 
 	*pack->ptr++ = 255;
@@ -1055,7 +1083,7 @@ void dhcpv4_relay_free(struct dhcpv4_relay *r, struct triton_context_t *ctx)
 	pthread_mutex_unlock(&relay_lock);
 }
 
-int dhcpv4_relay_send(struct dhcpv4_relay *relay, struct dhcpv4_packet *request, uint32_t server_id, const char *agent_circuit_id, const char *agent_remote_id)
+int dhcpv4_relay_send(struct dhcpv4_relay *relay, struct dhcpv4_packet *request, uint32_t server_id, const char *agent_circuit_id, const char *agent_remote_id, const char *link_selection)
 {
 	int n;
 	int len = request->ptr - request->data;
@@ -1063,7 +1091,8 @@ int dhcpv4_relay_send(struct dhcpv4_relay *relay, struct dhcpv4_packet *request,
 	struct dhcpv4_option *opt = NULL;
 	uint32_t _server_id;
 
-	if (!request->relay_agent && agent_remote_id && dhcpv4_packet_insert_opt82(request, agent_circuit_id, agent_remote_id))
+	if (!request->relay_agent && (agent_remote_id || link_selection) &&
+	    dhcpv4_packet_insert_opt82(request, agent_circuit_id, agent_remote_id, link_selection))
 		return -1;
 
 	request->hdr->giaddr = relay->giaddr;
@@ -1104,7 +1133,8 @@ int dhcpv4_relay_send(struct dhcpv4_relay *relay, struct dhcpv4_packet *request,
 
 int dhcpv4_relay_send_release(struct dhcpv4_relay *relay, uint8_t *chaddr, uint32_t xid, uint32_t ciaddr,
 	struct dhcpv4_option *client_id, struct dhcpv4_option *relay_agent,
-	const char *agent_circuit_id, const char *agent_remote_id)
+        const char *agent_circuit_id, const char *agent_remote_id,
+        const char *link_selection)
 {
 	struct dhcpv4_packet *pack;
 	int n, len;
@@ -1135,9 +1165,10 @@ int dhcpv4_relay_send_release(struct dhcpv4_relay *relay, uint8_t *chaddr, uint3
 
 	if (relay_agent && dhcpv4_packet_add_opt(pack, 82, relay_agent->data, relay_agent->len))
 		goto out_err;
-	else if (!relay_agent && agent_remote_id) {
+	else if (!relay_agent && (agent_remote_id || link_selection)) {
 		pack->ptr++;
-		if (dhcpv4_packet_insert_opt82(pack, agent_circuit_id, agent_remote_id))
+		if (dhcpv4_packet_insert_opt82(pack, agent_circuit_id, agent_remote_id,
+                                               link_selection))
 			goto out_err;
 		pack->ptr--;
 	}
diff --git a/accel-pppd/ctrl/ipoe/dhcpv4.h b/accel-pppd/ctrl/ipoe/dhcpv4.h
index 796b858..f5859f7 100644
--- a/accel-pppd/ctrl/ipoe/dhcpv4.h
+++ b/accel-pppd/ctrl/ipoe/dhcpv4.h
@@ -114,11 +114,12 @@ void dhcpv4_free(struct dhcpv4_serv *);
 struct dhcpv4_relay *dhcpv4_relay_create(const char *addr, in_addr_t giaddr, struct triton_context_t *ctx, triton_event_func recv);
 void dhcpv4_relay_free(struct dhcpv4_relay *, struct triton_context_t *);
 int dhcpv4_relay_send(struct dhcpv4_relay *relay, struct dhcpv4_packet *request, uint32_t server_id,
-	const char *agent_circuit_id, const char *agent_remote_id);
+        const char *agent_circuit_id, const char *agent_remote_id,
+        const char *link_selection);
 int dhcpv4_relay_send_release(struct dhcpv4_relay *relay, uint8_t *chaddr, uint32_t xid, uint32_t ciaddr,
 	struct dhcpv4_option *client_id, struct dhcpv4_option *relay_agent,
-	const char *agent_circuit_id, const char *agent_remote_id);
-
+        const char *agent_circuit_id, const char *agent_remote_id,
+        const char *link_selection);
 int dhcpv4_send_reply(int msg_type, struct dhcpv4_serv *serv, struct dhcpv4_packet *req,
 	uint32_t yiaddr, uint32_t siaddr, uint32_t router, uint32_t mask,
 	int lease_time, int renew_time, int rebind_time, struct dhcpv4_packet *relay_reply);
@@ -128,7 +129,7 @@ void dhcpv4_send_notify(struct dhcpv4_serv *serv, struct dhcpv4_packet *req, uns
 
 void dhcpv4_packet_ref(struct dhcpv4_packet *pack);
 struct dhcpv4_option *dhcpv4_packet_find_opt(struct dhcpv4_packet *pack, int type);
-int dhcpv4_packet_insert_opt82(struct dhcpv4_packet *pack, const char *agent_circuit_id, const char *agent_remote_id);
+int dhcpv4_packet_insert_opt82(struct dhcpv4_packet *pack, const char *agent_circuit_id, const char *agent_remote_id, const char *link_selection);
 void dhcpv4_packet_free(struct dhcpv4_packet *pack);
 struct dhcpv4_packet *dhcpv4_clone_radius(struct rad_packet_t *);
 
@@ -137,7 +138,7 @@ void dhcpv4_print_options(struct dhcpv4_packet *, void (*)(const char *, ...));
 
 void dhcpv4_print_packet(struct dhcpv4_packet *pack, int relay, void (*print)(const char *fmt, ...));
 
-int dhcpv4_parse_opt82(struct dhcpv4_option *opt, uint8_t **agent_circuit_id, uint8_t **agent_remote_id);
+int dhcpv4_parse_opt82(struct dhcpv4_option *opt, uint8_t **agent_circuit_id, uint8_t **agent_remote_id, uint8_t **link_selection);
 
 int dhcpv4_get_ip(struct dhcpv4_serv *serv, uint32_t *yiaddr, uint32_t *siaddr, int *mask);
 void dhcpv4_put_ip(struct dhcpv4_serv *serv, uint32_t ip);
diff --git a/accel-pppd/ctrl/ipoe/ipoe.c b/accel-pppd/ctrl/ipoe/ipoe.c
index b6ca46c..4a4f95d 100644
--- a/accel-pppd/ctrl/ipoe/ipoe.c
+++ b/accel-pppd/ctrl/ipoe/ipoe.c
@@ -173,6 +173,7 @@ static int conf_renew_time = LEASE_TIME/2;
 static int conf_rebind_time = LEASE_TIME/2 + LEASE_TIME/4 + LEASE_TIME/8;
 static int conf_verbose;
 static const char *conf_agent_remote_id;
+static const char *conf_link_selection;
 static int conf_proto;
 static LIST_HEAD(conf_offer_delay);
 static const char *conf_vlan_name;
@@ -258,6 +259,7 @@ static struct ipoe_session *ipoe_session_lookup(struct ipoe_serv *serv, struct d
 
 	uint8_t *agent_circuit_id = NULL;
 	uint8_t *agent_remote_id = NULL;
+	uint8_t *link_selection = NULL;
 	int opt82_match;
 
 	if (opt82_ses)
@@ -274,9 +276,10 @@ static struct ipoe_session *ipoe_session_lookup(struct ipoe_serv *serv, struct d
 		return ses;
 	}
 
-	if (!conf_check_mac_change || (pack->relay_agent && dhcpv4_parse_opt82(pack->relay_agent, &agent_circuit_id, &agent_remote_id))) {
+	if (!conf_check_mac_change || (pack->relay_agent && dhcpv4_parse_opt82(pack->relay_agent, &agent_circuit_id, &agent_remote_id, &link_selection))) {
 		agent_circuit_id = NULL;
 		agent_remote_id = NULL;
+		link_selection = NULL;
 	}
 
 	list_for_each_entry(ses, &serv->sessions, entry) {
@@ -288,12 +291,18 @@ static struct ipoe_session *ipoe_session_lookup(struct ipoe_serv *serv, struct d
 		if (opt82_match && agent_remote_id && !ses->agent_remote_id)
 			opt82_match = 0;
 
+		if (opt82_match && link_selection && !ses->link_selection)
+			opt82_match = 0;
+
 		if (opt82_match && !agent_circuit_id && ses->agent_circuit_id)
 			opt82_match = 0;
 
 		if (opt82_match && !agent_remote_id && ses->agent_remote_id)
 			opt82_match = 0;
 
+		if (opt82_match && !link_selection && ses->link_selection)
+			opt82_match = 0;
+
 		if (opt82_match && agent_circuit_id) {
 			if (*agent_circuit_id != *ses->agent_circuit_id)
 				opt82_match = 0;
@@ -310,6 +319,14 @@ static struct ipoe_session *ipoe_session_lookup(struct ipoe_serv *serv, struct d
 				opt82_match = 0;
 		}
 
+		if (opt82_match && link_selection) {
+			if (*link_selection != *ses->link_selection)
+				opt82_match = 0;
+
+			if (memcmp(link_selection + 1, ses->link_selection + 1, *link_selection))
+				opt82_match = 0;
+		}
+
 		if (opt82_match && opt82_ses)
 			*opt82_ses = ses;
 
@@ -350,12 +367,18 @@ static struct ipoe_session *ipoe_session_lookup(struct ipoe_serv *serv, struct d
 		if (opt82_match && agent_remote_id && !ses->agent_remote_id)
 			continue;
 
+		if (opt82_match && link_selection && !ses->link_selection)
+			continue;
+
 		if (opt82_match && !agent_circuit_id && ses->agent_circuit_id)
 			continue;
 
 		if (opt82_match && !agent_remote_id && ses->agent_remote_id)
 			continue;
 
+		if (opt82_match && !link_selection && ses->link_selection)
+			continue;
+
 		if (opt82_match && agent_circuit_id) {
 			if (*agent_circuit_id != *ses->agent_circuit_id)
 				continue;
@@ -372,6 +395,14 @@ static struct ipoe_session *ipoe_session_lookup(struct ipoe_serv *serv, struct d
 				continue;
 		}
 
+		if (opt82_match && link_selection) {
+			if (*link_selection != *ses->link_selection)
+				continue;
+
+			if (memcmp(link_selection + 1, ses->link_selection + 1, *link_selection))
+				continue;
+		}
+
 		*opt82_ses = ses;
 		break;
 	}
@@ -417,7 +448,7 @@ static void ipoe_relay_timeout(struct triton_timer_t *t)
 
 		ap_session_terminate(&ses->ses, TERM_LOST_CARRIER, 1);
 	} else
-		dhcpv4_relay_send(ses->serv->dhcpv4_relay, ses->dhcpv4_request, ses->relay_server_id, ses->serv->ifname, conf_agent_remote_id);
+		dhcpv4_relay_send(ses->serv->dhcpv4_relay, ses->dhcpv4_request, ses->relay_server_id, ses->serv->ifname, conf_agent_remote_id, conf_link_selection);
 }
 
 
@@ -684,7 +715,7 @@ cont:
 	ap_session_set_ifindex(&ses->ses);
 
 	if (ses->dhcpv4_request && ses->serv->dhcpv4_relay) {
-		dhcpv4_relay_send(ses->serv->dhcpv4_relay, ses->dhcpv4_request, ses->relay_server_id, ses->serv->ifname, conf_agent_remote_id);
+		dhcpv4_relay_send(ses->serv->dhcpv4_relay, ses->dhcpv4_request, ses->relay_server_id, ses->serv->ifname, conf_agent_remote_id, conf_link_selection);
 
 		ses->timer.expire = ipoe_relay_timeout;
 		ses->timer.period = conf_relay_timeout * 1000;
@@ -1077,7 +1108,7 @@ static void ipoe_session_activate(struct dhcpv4_packet *pack)
 	ses->dhcpv4_request = pack;
 
 	if (ses->serv->dhcpv4_relay)
-		dhcpv4_relay_send(ses->serv->dhcpv4_relay, ses->dhcpv4_request, ses->relay_server_id, ses->serv->ifname, conf_agent_remote_id);
+		dhcpv4_relay_send(ses->serv->dhcpv4_relay, ses->dhcpv4_request, ses->relay_server_id, ses->serv->ifname, conf_agent_remote_id, conf_link_selection);
 	else
 		__ipoe_session_activate(ses);
 }
@@ -1097,7 +1128,7 @@ static void ipoe_session_keepalive(struct dhcpv4_packet *pack)
 	ses->xid = ses->dhcpv4_request->hdr->xid;
 
 	if (/*ses->ses.state == AP_STATE_ACTIVE &&*/ ses->serv->dhcpv4_relay) {
-		dhcpv4_relay_send(ses->serv->dhcpv4_relay, ses->dhcpv4_request, ses->relay_server_id, ses->serv->ifname, conf_agent_remote_id);
+		dhcpv4_relay_send(ses->serv->dhcpv4_relay, ses->dhcpv4_request, ses->relay_server_id, ses->serv->ifname, conf_agent_remote_id, conf_link_selection);
 		return;
 	}
 
@@ -1121,7 +1152,7 @@ static void ipoe_session_decline(struct dhcpv4_packet *pack)
 	}
 
 	if (pack->msg_type == DHCPDECLINE && ses->serv->dhcpv4_relay)
-		dhcpv4_relay_send(ses->serv->dhcpv4_relay, pack, 0, ses->serv->ifname, conf_agent_remote_id);
+		dhcpv4_relay_send(ses->serv->dhcpv4_relay, pack, 0, ses->serv->ifname, conf_agent_remote_id, conf_link_selection);
 
 	dhcpv4_packet_free(pack);
 
@@ -1233,7 +1264,7 @@ static void ipoe_session_finished(struct ap_session *s)
 		dhcpv4_put_ip(ses->serv->dhcpv4, ses->yiaddr);
 
 	if (ses->relay_addr && ses->serv->dhcpv4_relay)
-		dhcpv4_relay_send_release(ses->serv->dhcpv4_relay, ses->hwaddr, ses->xid, ses->yiaddr, ses->client_id, ses->relay_agent, ses->serv->ifname, conf_agent_remote_id);
+		dhcpv4_relay_send_release(ses->serv->dhcpv4_relay, ses->hwaddr, ses->xid, ses->yiaddr, ses->client_id, ses->relay_agent, ses->serv->ifname, conf_agent_remote_id, conf_link_selection);
 
 	if (ses->dhcpv4)
 		dhcpv4_free(ses->dhcpv4);
@@ -1382,7 +1413,7 @@ static struct ipoe_session *ipoe_session_create_dhcpv4(struct ipoe_serv *serv, s
 		ses->relay_agent->data = (uint8_t *)(ses->relay_agent + 1);
 		memcpy(ses->relay_agent->data, pack->relay_agent->data, pack->relay_agent->len);
 		ptr += sizeof(struct dhcpv4_option) + pack->relay_agent->len;
-		if (dhcpv4_parse_opt82(ses->relay_agent, &ses->agent_circuit_id, &ses->agent_remote_id))
+		if (dhcpv4_parse_opt82(ses->relay_agent, &ses->agent_circuit_id, &ses->agent_remote_id, &ses->link_selection))
 			ses->relay_agent = NULL;
 	}
 
@@ -1440,6 +1471,7 @@ static void ipoe_ses_recv_dhcpv4(struct dhcpv4_serv *dhcpv4, struct dhcpv4_packe
 	int opt82_match;
 	uint8_t *agent_circuit_id = NULL;
 	uint8_t *agent_remote_id = NULL;
+	uint8_t *link_selection = NULL;
 
 	if (conf_verbose) {
 		log_ppp_info2("recv ");
@@ -1453,9 +1485,10 @@ static void ipoe_ses_recv_dhcpv4(struct dhcpv4_serv *dhcpv4, struct dhcpv4_packe
 		return;
 	}
 
-	if (pack->relay_agent && dhcpv4_parse_opt82(pack->relay_agent, &agent_circuit_id, &agent_remote_id)) {
+	if (pack->relay_agent && dhcpv4_parse_opt82(pack->relay_agent, &agent_circuit_id, &agent_remote_id, &link_selection)) {
 		agent_circuit_id = NULL;
 		agent_remote_id = NULL;
+		link_selection = NULL;
 	}
 
 	opt82_match = pack->relay_agent != NULL;
@@ -1515,7 +1548,7 @@ static void ipoe_ses_recv_dhcpv4(struct dhcpv4_serv *dhcpv4, struct dhcpv4_packe
 			if (pack->server_id == ses->siaddr)
 				dhcpv4_send_nak(dhcpv4, pack, "Wrong session");
 			else if (ses->serv->dhcpv4_relay)
-				dhcpv4_relay_send(ses->serv->dhcpv4_relay, pack, 0, ses->serv->ifname, conf_agent_remote_id);
+				dhcpv4_relay_send(ses->serv->dhcpv4_relay, pack, 0, ses->serv->ifname, conf_agent_remote_id, conf_link_selection);
 
 			triton_context_call(ses->ctrl.ctx, (triton_event_func)__ipoe_session_terminate, &ses->ses);
 		} else {
@@ -3802,6 +3835,7 @@ static void load_config(void)
 	const char *opt;
 	struct conf_sect_t *s = conf_get_section("ipoe");
 	struct conf_option_t *opt1;
+	struct in_addr dummy;
 
 	if (!s)
 		return;
@@ -3969,6 +4003,10 @@ static void load_config(void)
 	else
 		conf_agent_remote_id = NULL;
 
+	opt = conf_get_opt("ipoe", "link-selection");
+	if (opt && inet_pton(AF_INET, opt, &dummy) > 0)
+		conf_link_selection = opt;
+
 	opt = conf_get_opt("ipoe", "ipv6");
 	if (opt)
 		conf_ipv6 = atoi(opt);
diff --git a/accel-pppd/ctrl/ipoe/ipoe.h b/accel-pppd/ctrl/ipoe/ipoe.h
index 75948b1..07dce1e 100644
--- a/accel-pppd/ctrl/ipoe/ipoe.h
+++ b/accel-pppd/ctrl/ipoe/ipoe.h
@@ -86,6 +86,7 @@ struct ipoe_session {
 	struct dhcpv4_option *relay_agent;
 	uint8_t *agent_circuit_id;
 	uint8_t *agent_remote_id;
+	uint8_t *link_selection;
 	uint32_t xid;
 	uint32_t giaddr;
 	uint32_t yiaddr;