netifd: Make interface identifier of delegated IPv6 address configurable

The ip6ifaceid UCI interface parameter makes the interface identifier of the delegated IPv6 address configurable.
The parameter can have the following values:
    eui64 : Interface identifier is generated from the interface's MAC address
    random : Interface identifier is generated randomly
    fixed value : Interface identifier is a fixed value (eg ::1:2)

The latter is the default value with a fixed value of ::1 for backwards compatibility

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>
Signed-off-by: Joeri Barbarien <joeri.barbarien@gmail.com>

4 files changed, 107 insertions, 3 deletions

diff --git a/interface-ip.c b/interface-ip.c
index 6659f8b..1a22ce6 100644
--- a/interface-ip.c
+++ b/interface-ip.c
@@ -648,6 +648,56 @@ interface_update_host_route(struct vlist_tree *tree,
 	}
 }
 
+static void
+random_ifaceid(struct in6_addr *addr)
+{
+	static bool initialized = false;
+	struct timeval t;
+
+	if (!initialized) {
+		long int seed = 0;
+		gettimeofday(&t, NULL);
+		seed = t.tv_sec ^ t.tv_usec ^ getpid();
+		srand48(seed);
+		initialized = true;
+	}
+	addr->s6_addr32[2] = (uint32_t)mrand48();
+	addr->s6_addr32[3] = (uint32_t)mrand48();
+}
+
+static void
+eui64_ifaceid(struct interface *iface, struct in6_addr *addr)
+{
+	/* get mac address */
+	uint8_t *macaddr = iface->l3_dev.dev->settings.macaddr;
+	uint8_t *ifaceid = addr->s6_addr + 8;
+	memcpy(ifaceid,macaddr,3);
+	memcpy(ifaceid + 5,macaddr + 3, 3);
+	ifaceid[3] = 0xff;
+	ifaceid[4] = 0xfe;
+	ifaceid[0] ^= 0x02;
+}
+
+static void
+generate_ifaceid(struct interface *iface, struct in6_addr *addr)
+{
+	/* generate new iface id */
+	switch (iface->assignment_iface_id_selection) {
+	case IFID_FIXED:
+		/* fixed */
+		/* copy host part from assignment_fixed_iface_id */
+		memcpy(addr->s6_addr + 8, iface->assignment_fixed_iface_id.s6_addr + 8, 8);
+		break;
+	case IFID_RANDOM:
+		/* randomize last 64 bits */
+		random_ifaceid(addr);
+		break;
+	case IFID_EUI64:
+		/* eui64 */
+		eui64_ifaceid(iface, addr);
+		break;
+	}
+}
 
 static void
 interface_set_prefix_address(struct device_prefix_assignment *assignment,
@@ -661,9 +711,16 @@ interface_set_prefix_address(struct device_prefix_assignment *assignment,
 
 	struct device_addr addr;
 	memset(&addr, 0, sizeof(addr));
-	addr.addr.in6 = prefix->addr;
-	addr.addr.in6.s6_addr32[1] |= htonl(assignment->assigned);
-	addr.addr.in6.s6_addr[15] += 1;
+
+	if (IN6_IS_ADDR_UNSPECIFIED(&assignment->addr)) {
+		addr.addr.in6 = prefix->addr;
+		addr.addr.in6.s6_addr32[1] |= htonl(assignment->assigned);
+		generate_ifaceid(iface, &addr.addr.in6);
+		assignment->addr = addr.addr.in6;
+	}
+	else
+		addr.addr.in6 = assignment->addr;
+
 	addr.mask = assignment->length;
 	addr.flags = DEVADDR_INET6;
 	addr.preferred_until = prefix->preferred_until;
@@ -775,6 +832,7 @@ static void interface_update_prefix_assignments(struct device_prefix *prefix, bo
 	c->assigned = 1 << (64 - prefix->length);
 	c->length = 64;
 	c->name[0] = 0;
+	c->addr = in6addr_any;
 	list_add(&c->head, &prefix->assignments);
 
 	// Excluded prefix
@@ -784,6 +842,7 @@ static void interface_update_prefix_assignments(struct device_prefix *prefix, bo
 		c->assigned = ntohl(prefix->excl_addr.s6_addr32[1]) &
 				((1 << (64 - prefix->length)) - 1);
 		c->length = prefix->excl_length;
+		c->addr = in6addr_any;
 		memcpy(c->name, name, sizeof(name));
 		list_add(&c->head, &prefix->assignments);
 	}
@@ -815,6 +874,7 @@ static void interface_update_prefix_assignments(struct device_prefix *prefix, bo
 		c = malloc(sizeof(*c) + namelen);
 		c->length = iface->assignment_length;
 		c->assigned = iface->assignment_hint;
+		c->addr = in6addr_any;
 		c->enabled = false;
 		memcpy(c->name, iface->name, namelen);
 
diff --git a/interface-ip.h b/interface-ip.h
index a5612e5..7c4a8ae 100644
--- a/interface-ip.h
+++ b/interface-ip.h
@@ -59,6 +59,7 @@ struct device_prefix_assignment {
 	struct list_head head;
 	int32_t assigned;
 	uint8_t length;
+	struct in6_addr addr;
 	bool enabled;
 	char name[];
 };
diff --git a/interface.c b/interface.c
index 83d7f94..4ab2431 100644
--- a/interface.c
+++ b/interface.c
@@ -43,6 +43,7 @@ enum {
 	IFACE_ATTR_IP6TABLE,
 	IFACE_ATTR_IP6CLASS,
 	IFACE_ATTR_DELEGATE,
+	IFACE_ATTR_IP6IFACEID,
 	IFACE_ATTR_FORCE_LINK,
 	IFACE_ATTR_MAX
 };
@@ -63,6 +64,7 @@ static const struct blobmsg_policy iface_attrs[IFACE_ATTR_MAX] = {
 	[IFACE_ATTR_IP6TABLE] = { .name = "ip6table", .type = BLOBMSG_TYPE_STRING },
 	[IFACE_ATTR_IP6CLASS] = { .name = "ip6class", .type = BLOBMSG_TYPE_ARRAY },
 	[IFACE_ATTR_DELEGATE] = { .name = "delegate", .type = BLOBMSG_TYPE_BOOL },
+	[IFACE_ATTR_IP6IFACEID] = { .name = "ip6ifaceid", .type = BLOBMSG_TYPE_STRING },
 	[IFACE_ATTR_FORCE_LINK] = { .name = "force_link", .type = BLOBMSG_TYPE_BOOL },
 };
 
@@ -423,6 +425,10 @@ interface_merge_assignment_data(struct interface *old, struct interface *new)
 {
 	bool changed = (old->assignment_hint != new->assignment_hint ||
 			old->assignment_length != new->assignment_length ||
+			old->assignment_iface_id_selection != new->assignment_iface_id_selection ||
+			(old->assignment_iface_id_selection == IFID_FIXED &&
+			 memcmp(&old->assignment_fixed_iface_id, &new->assignment_fixed_iface_id,
+				sizeof(old->assignment_fixed_iface_id))) ||
 			list_empty(&old->assignment_classes) != list_empty(&new->assignment_classes));
 
 	struct interface_assignment_class *c;
@@ -455,6 +461,8 @@ interface_merge_assignment_data(struct interface *old, struct interface *new)
 	if (changed) {
 		old->assignment_hint = new->assignment_hint;
 		old->assignment_length = new->assignment_length;
+		old->assignment_iface_id_selection = new->assignment_iface_id_selection;
+		old->assignment_fixed_iface_id = new->assignment_fixed_iface_id;
 		interface_refresh_assignments(true);
 	}
 }
@@ -703,6 +711,33 @@ interface_alloc(const char *name, struct blob_attr *config)
 	if ((cur = tb[IFACE_ATTR_IP6ASSIGN]))
 		iface->assignment_length = blobmsg_get_u32(cur);
 
+	/* defaults */
+	iface->assignment_iface_id_selection = IFID_FIXED;
+	iface->assignment_fixed_iface_id = in6addr_any;
+	iface->assignment_fixed_iface_id.s6_addr[15] = 1;
+
+	if ((cur = tb[IFACE_ATTR_IP6IFACEID])) {
+		const char *ifaceid = blobmsg_data(cur);
+		if (!strcmp(ifaceid, "random")) {
+			iface->assignment_iface_id_selection = IFID_RANDOM;
+		}
+		else if (!strcmp(ifaceid, "eui64")) {
+			iface->assignment_iface_id_selection = IFID_EUI64;
+		}
+		else {
+			/* we expect an IPv6 address with network id zero here -> fixed iface id
+			   if we cannot parse -> revert to iface id 1 */
+			if (inet_pton(AF_INET6,ifaceid,&iface->assignment_fixed_iface_id) != 1 ||
+					iface->assignment_fixed_iface_id.s6_addr32[0] != 0 ||
+					iface->assignment_fixed_iface_id.s6_addr32[1] != 0) {
+				iface->assignment_fixed_iface_id = in6addr_any;
+				iface->assignment_fixed_iface_id.s6_addr[15] = 1;
+				netifd_log_message(L_WARNING, "Failed to parse ip6ifaceid for interface '%s', \
+							falling back to iface id 1.\n", iface->name);
+			}
+		}
+	}
+
 	iface->assignment_hint = -1;
 	if ((cur = tb[IFACE_ATTR_IP6HINT]))
 		iface->assignment_hint = strtol(blobmsg_get_string(cur), NULL, 16) &
diff --git a/interface.h b/interface.h
index 90087fc..8eeb7db 100644
--- a/interface.h
+++ b/interface.h
@@ -41,6 +41,12 @@ enum interface_config_state {
 	IFC_REMOVE
 };
 
+enum interface_id_selection_type {
+	IFID_FIXED,
+	IFID_RANDOM,
+	IFID_EUI64
+};
+
 enum interface_update_flags {
 	IUF_ADDRESS	= (1 << 0),
 	IUF_ROUTE	= (1 << 1),
@@ -139,6 +145,8 @@ struct interface {
 	unsigned int ip6table;
 
 	/* IPv6 assignment parameters */
+	enum interface_id_selection_type assignment_iface_id_selection;
+	struct in6_addr assignment_fixed_iface_id;
 	uint8_t assignment_length;
 	int32_t assignment_hint;
 	struct list_head assignment_classes;