Add support for (managed) prefixes of length 65-96

5 files changed, 44 insertions, 40 deletions

diff --git a/src/dhcpv6-ia.c b/src/dhcpv6-ia.c
index 4d68258..cca6664 100644
--- a/src/dhcpv6-ia.c
+++ b/src/dhcpv6-ia.c
@@ -233,7 +233,7 @@ void dhcpv6_write_statefile(void)
 
 					struct in6_addr addr;
 					for (size_t i = 0; i < iface->ia_addr_len; ++i) {
-						if (iface->ia_addr[i].prefix > 64)
+						if (iface->ia_addr[i].prefix > 96)
 							continue;
 
 						addr = iface->ia_addr[i].addr;
@@ -451,7 +451,6 @@ static void update(struct interface *iface)
 		if (addr[i].prefix > minprefix)
 			minprefix = addr[i].prefix;
 
-		addr[i].addr.s6_addr32[2] = 0;
 		addr[i].addr.s6_addr32[3] = 0;
 
 		if (addr[i].preferred < UINT32_MAX - now)
@@ -604,7 +603,7 @@ static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 				uint32_t prefix_pref = iface->ia_addr[i].preferred - now;
 				uint32_t prefix_valid = iface->ia_addr[i].valid - now;
 
-				if (iface->ia_addr[i].prefix > 64 ||
+				if (iface->ia_addr[i].prefix > 96 ||
 						iface->ia_addr[i].preferred <= (uint32_t)now)
 					continue;
 
@@ -712,7 +711,7 @@ static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 				bool found = false;
 				if (a) {
 					for (size_t i = 0; i < iface->ia_addr_len; ++i) {
-						if (iface->ia_addr[i].prefix > 64 ||
+						if (iface->ia_addr[i].prefix > 96 ||
 								iface->ia_addr[i].preferred <= (uint32_t)now)
 							continue;
 
diff --git a/src/ndp.c b/src/ndp.c
index 02c2dbd..6d18bb5 100644
--- a/src/ndp.c
+++ b/src/ndp.c
@@ -364,41 +364,12 @@ static void free_neighbor(struct ndp_neighbor *n)
 	--neighbor_count;
 }
 
-
-static bool match_neighbor(struct ndp_neighbor *n, struct in6_addr *addr)
-{
-	if (n->len <= 32)
-		return ntohl(n->addr.s6_addr32[0]) >> (32 - n->len) ==
-				ntohl(addr->s6_addr32[0]) >> (32 - n->len);
-
-	if (n->addr.s6_addr32[0] != addr->s6_addr32[0])
-		return false;
-
-	if (n->len <= 64)
-		return ntohl(n->addr.s6_addr32[1]) >> (64 - n->len) ==
-				ntohl(addr->s6_addr32[1]) >> (64 - n->len);
-
-	if (n->addr.s6_addr32[1] != addr->s6_addr32[1])
-		return false;
-
-	if (n->len <= 96)
-		return ntohl(n->addr.s6_addr32[2]) >> (96 - n->len) ==
-				ntohl(addr->s6_addr32[2]) >> (96 - n->len);
-
-	if (n->addr.s6_addr32[2] != addr->s6_addr32[2])
-		return false;
-
-	return ntohl(n->addr.s6_addr32[3]) >> (128 - n->len) ==
-			ntohl(addr->s6_addr32[3]) >> (128 - n->len);
-}
-
-
 static struct ndp_neighbor* find_neighbor(struct in6_addr *addr, bool strict)
 {
 	time_t now = time(NULL);
 	struct ndp_neighbor *n, *e;
 	list_for_each_entry_safe(n, e, &neighbors, head) {
-		if ((!strict && match_neighbor(n, addr)) ||
+		if ((!strict && !odhcpd_bmemcmp(&n->addr, addr, n->len)) ||
 				(n->len == 128 && IN6_ARE_ADDR_EQUAL(&n->addr, addr)))
 			return n;
 
diff --git a/src/odhcpd.c b/src/odhcpd.c
index f40cea0..25a6047 100644
--- a/src/odhcpd.c
+++ b/src/odhcpd.c
@@ -427,3 +427,33 @@ void odhcpd_hexlify(char *dst, const uint8_t *src, size_t len)
 	}
 	*dst = 0;
 }
+
+
+int odhcpd_bmemcmp(const void *av, const void *bv, size_t bits)
+{
+	const uint8_t *a = av, *b = bv;
+	size_t bytes = bits / 8;
+	bits %= 8;
+
+	int res = memcmp(a, b, bytes);
+	if (res == 0 && bits > 0)
+		res = (a[bytes] >> (8 - bits)) - (b[bytes] >> (8 - bits));
+
+	return res;
+}
+
+
+void odhcpd_bmemcpy(void *av, const void *bv, size_t bits)
+{
+	uint8_t *a = av;
+	const uint8_t *b = bv;
+
+	size_t bytes = bits / 8;
+	bits %= 8;
+	memcpy(a, b, bytes);
+
+	if (bits > 0) {
+		uint8_t mask = (1 << (8 - bits)) - 1;
+		a[bytes] = (a[bytes] & mask) | ((~mask) & b[bytes]);
+	}
+}
diff --git a/src/odhcpd.h b/src/odhcpd.h
index 789f696..010cd9e 100644
--- a/src/odhcpd.h
+++ b/src/odhcpd.h
@@ -188,6 +188,9 @@ time_t odhcpd_time(void);
 ssize_t odhcpd_unhexlify(uint8_t *dst, size_t len, const char *src);
 void odhcpd_hexlify(char *dst, const uint8_t *src, size_t len);
 
+int odhcpd_bmemcmp(const void *av, const void *bv, size_t bits);
+void odhcpd_bmemcpy(void *av, const void *bv, size_t bits);
+
 int config_parse_interface(void *data, size_t len, const char *iname, bool overwrite);
 
 #ifdef WITH_UBUS
diff --git a/src/router.c b/src/router.c
index 372c400..907011a 100644
--- a/src/router.c
+++ b/src/router.c
@@ -296,7 +296,7 @@ static void send_router_advert(struct uloop_timeout *event)
 
 	for (ssize_t i = 0; i < ipcnt; ++i) {
 		struct odhcpd_ipaddr *addr = &addrs[i];
-		if (addr->prefix > 64 || addr->has_class)
+		if (addr->prefix > 96 || addr->has_class)
 			continue; // Address not suitable
 
 		if (addr->preferred > MaxPreferredTime)
@@ -307,8 +307,9 @@ static void send_router_advert(struct uloop_timeout *event)
 
 		struct nd_opt_prefix_info *p = NULL;
 		for (size_t i = 0; i < cnt; ++i) {
-			if (!memcmp(&adv.prefix[i].nd_opt_pi_prefix,
-					&addr->addr, 8))
+			if (addr->prefix == adv.prefix[i].nd_opt_pi_prefix_len &&
+					!odhcpd_bmemcmp(&adv.prefix[i].nd_opt_pi_prefix,
+					&addr->addr, addr->prefix))
 				p = &adv.prefix[i];
 		}
 
@@ -326,14 +327,14 @@ static void send_router_advert(struct uloop_timeout *event)
 				maxpreferred = 1000 * addr->preferred;
 		}
 
-		memcpy(&p->nd_opt_pi_prefix, &addr->addr, 8);
+		odhcpd_bmemcpy(&p->nd_opt_pi_prefix, &addr->addr, addr->prefix);
 		p->nd_opt_pi_type = ND_OPT_PREFIX_INFORMATION;
 		p->nd_opt_pi_len = 4;
-		p->nd_opt_pi_prefix_len = 64;
+		p->nd_opt_pi_prefix_len = (addr->prefix < 64) ? 64 : addr->prefix;
 		p->nd_opt_pi_flags_reserved = 0;
 		if (!iface->ra_not_onlink)
 			p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_ONLINK;
-		if (iface->managed < RELAYD_MANAGED_NO_AFLAG)
+		if (iface->managed < RELAYD_MANAGED_NO_AFLAG && addr->prefix <= 64)
 			p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_AUTO;
 		p->nd_opt_pi_valid_time = htonl(addr->valid);
 		p->nd_opt_pi_preferred_time = htonl(addr->preferred);