treewide: rework code to get rid of fixed IPv6 address arrays

Rework code to get rid of RELAYD_MAX_PREFIXES and RELAYD_MAX_ADDRS
by using dynamic IPv6 address array allocation.

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>

6 files changed, 73 insertions, 45 deletions

diff --git a/src/config.c b/src/config.c
index 9ce20ef..1276b6f 100644
--- a/src/config.c
+++ b/src/config.c
@@ -237,6 +237,7 @@ static void close_interface(struct interface *iface)
 	setup_dhcpv4_interface(iface, false);
 
 	clean_interface(iface);
+	free(iface->ia_addr);
 	free(iface->ifname);
 	free(iface);
 }
diff --git a/src/dhcpv6.c b/src/dhcpv6.c
index ebb0c80..3128968 100644
--- a/src/dhcpv6.c
+++ b/src/dhcpv6.c
@@ -335,14 +335,15 @@ static void handle_client_request(void *addr, void *data, size_t len,
 			iov[IOV_CERID].iov_len = sizeof(cerid);
 
 			if (IN6_IS_ADDR_UNSPECIFIED(&cerid.addr)) {
-				struct odhcpd_ipaddr addrs[32];
-				ssize_t len = odhcpd_get_interface_addresses(0, addrs,
-						ARRAY_SIZE(addrs));
+				struct odhcpd_ipaddr *addrs;
+				ssize_t len = odhcpd_get_interface_addresses(0, &addrs);
 
 				for (ssize_t i = 0; i < len; ++i)
 					if (IN6_IS_ADDR_UNSPECIFIED(&cerid.addr)
 							|| memcmp(&addrs[i].addr, &cerid.addr, sizeof(cerid.addr)) < 0)
 						cerid.addr = addrs[i].addr;
+
+				free(addrs);
 			}
 #endif
 		}
@@ -521,17 +522,18 @@ static void relay_client_request(struct sockaddr_in6 *source,
 	memcpy(&hdr.interface_id_data, &ifindex, sizeof(ifindex));
 
 	// Detect public IP of slave interface to use as link-address
-	struct odhcpd_ipaddr ip;
-	if (odhcpd_get_interface_addresses(iface->ifindex, &ip, 1) < 1) {
+	struct odhcpd_ipaddr *ip = NULL;
+	if (odhcpd_get_interface_addresses(iface->ifindex, &ip) < 1) {
 		// No suitable address! Is the slave not configured yet?
 		// Detect public IP of master interface and use it instead
 		// This is WRONG and probably violates the RFC. However
 		// otherwise we have a hen and egg problem because the
 		// slave-interface cannot be auto-configured.
-		if (odhcpd_get_interface_addresses(master->ifindex, &ip, 1) < 1)
+		if (odhcpd_get_interface_addresses(master->ifindex, &ip) < 1)
 			return; // Could not obtain a suitable address
 	}
-	memcpy(&hdr.link_address, &ip.addr, sizeof(hdr.link_address));
+	memcpy(&hdr.link_address, &ip[0].addr, sizeof(hdr.link_address));
+	free(ip);
 
 	struct sockaddr_in6 dhcpv6_servers = {AF_INET6,
 			htons(DHCPV6_SERVER_PORT), 0, ALL_DHCPV6_SERVERS, 0};
diff --git a/src/ndp.c b/src/ndp.c
index b686262..8488fc5 100644
--- a/src/ndp.c
+++ b/src/ndp.c
@@ -352,9 +352,9 @@ static int prefixcmp(const void *va, const void *vb)
 // Check address update
 static void check_addr_updates(struct interface *iface)
 {
-	struct odhcpd_ipaddr addr[RELAYD_MAX_ADDRS] = {{IN6ADDR_ANY_INIT, 0, 0, 0, 0}};
+	struct odhcpd_ipaddr *addr = NULL;
 	time_t now = odhcpd_time();
-	ssize_t len = odhcpd_get_interface_addresses(iface->ifindex, addr, ARRAY_SIZE(addr));
+	ssize_t len = odhcpd_get_interface_addresses(iface->ifindex, &addr);
 
 	if (len < 0)
 		return;
@@ -380,7 +380,8 @@ static void check_addr_updates(struct interface *iface)
 	if (change)
 		dhcpv6_ia_preupdate(iface);
 
-	memcpy(iface->ia_addr, addr, len * sizeof(*addr));
+	free(iface->ia_addr);
+	iface->ia_addr = addr;
 	iface->ia_addr_len = len;
 
 	if (change)
diff --git a/src/odhcpd.c b/src/odhcpd.c
index 8a1c66e..ee628a5 100644
--- a/src/odhcpd.c
+++ b/src/odhcpd.c
@@ -25,6 +25,7 @@
 #include <signal.h>
 #include <stdbool.h>
 #include <syslog.h>
+#include <alloca.h>
 
 #include <arpa/inet.h>
 #include <net/if.h>
@@ -221,8 +222,7 @@ ssize_t odhcpd_send(int socket, struct sockaddr_in6 *dest,
 
 struct addr_info {
 	int ifindex;
-	struct odhcpd_ipaddr *addrs;
-	size_t addrs_sz;
+	struct odhcpd_ipaddr **addrs;
 	int pending;
 	ssize_t ret;
 };
@@ -230,11 +230,12 @@ struct addr_info {
 static int cb_valid_handler(struct nl_msg *msg, void *arg)
 {
 	struct addr_info *ctxt = (struct addr_info *)arg;
+	struct odhcpd_ipaddr *addrs = *(ctxt->addrs);
 	struct nlmsghdr *hdr = nlmsg_hdr(msg);
 	struct ifaddrmsg *ifa;
 	struct nlattr *nla[__IFA_MAX];
 
-	if (hdr->nlmsg_type != RTM_NEWADDR || ctxt->ret >= (ssize_t)ctxt->addrs_sz)
+	if (hdr->nlmsg_type != RTM_NEWADDR)
 		return NL_SKIP;
 
 	ifa = NLMSG_DATA(hdr);
@@ -246,23 +247,28 @@ static int cb_valid_handler(struct nl_msg *msg, void *arg)
 	if (!nla[IFA_ADDRESS])
 		return NL_SKIP;
 
-	memset(&ctxt->addrs[ctxt->ret], 0, sizeof(ctxt->addrs[ctxt->ret]));
-	ctxt->addrs[ctxt->ret].prefix = ifa->ifa_prefixlen;
+	addrs = realloc(addrs, sizeof(*addrs)*(ctxt->ret + 1));
+	if (!addrs)
+		return NL_SKIP;
+
+	memset(&addrs[ctxt->ret], 0, sizeof(addrs[ctxt->ret]));
+	addrs[ctxt->ret].prefix = ifa->ifa_prefixlen;
 
-	nla_memcpy(&ctxt->addrs[ctxt->ret].addr, nla[IFA_ADDRESS],
-			sizeof(ctxt->addrs[ctxt->ret].addr));
+	nla_memcpy(&addrs[ctxt->ret].addr, nla[IFA_ADDRESS],
+			sizeof(addrs[ctxt->ret].addr));
 
 	if (nla[IFA_CACHEINFO]) {
 		struct ifa_cacheinfo *ifc = nla_data(nla[IFA_CACHEINFO]);
 
-		ctxt->addrs[ctxt->ret].preferred = ifc->ifa_prefered;
-		ctxt->addrs[ctxt->ret].valid = ifc->ifa_valid;
+		addrs[ctxt->ret].preferred = ifc->ifa_prefered;
+		addrs[ctxt->ret].valid = ifc->ifa_valid;
 	}
 
 	if (ifa->ifa_flags & IFA_F_DEPRECATED)
-		ctxt->addrs[ctxt->ret].preferred = 0;
+		addrs[ctxt->ret].preferred = 0;
 
 	ctxt->ret++;
+	*(ctxt->addrs) = addrs;
 
 	return NL_OK;
 }
@@ -288,8 +294,7 @@ static int cb_error_handler(_unused struct sockaddr_nl *nla, struct nlmsgerr *er
 }
 
 // Detect an IPV6-address currently assigned to the given interface
-ssize_t odhcpd_get_interface_addresses(int ifindex,
-		struct odhcpd_ipaddr *addrs, size_t cnt)
+ssize_t odhcpd_get_interface_addresses(int ifindex, struct odhcpd_ipaddr **addrs)
 {
 	struct nl_msg *msg;
 	struct ifaddrmsg ifa = {
@@ -302,7 +307,6 @@ ssize_t odhcpd_get_interface_addresses(int ifindex,
 	struct addr_info ctxt = {
 		.ifindex = ifindex,
 		.addrs = addrs,
-		.addrs_sz = cnt,
 		.ret = 0,
 		.pending = 1,
 	};
diff --git a/src/odhcpd.h b/src/odhcpd.h
index 93adca6..8a196ea 100644
--- a/src/odhcpd.h
+++ b/src/odhcpd.h
@@ -41,8 +41,6 @@
 #define ND_OPT_DNS_SEARCH 31
 
 #define RELAYD_BUFFER_SIZE 8192
-#define RELAYD_MAX_PREFIXES 8
-#define RELAYD_MAX_ADDRS 8
 
 #define INFINITE_VALID(x) ((x) == 0)
 
@@ -123,7 +121,7 @@ struct interface {
 	// Runtime data
 	struct uloop_timeout timer_rs;
 	struct list_head ia_assignments;
-	struct odhcpd_ipaddr ia_addr[RELAYD_MAX_ADDRS];
+	struct odhcpd_ipaddr *ia_addr;
 	size_t ia_addr_len;
 
 	// DHCPv4
@@ -206,7 +204,7 @@ ssize_t odhcpd_send(int socket, struct sockaddr_in6 *dest,
 		struct iovec *iov, size_t iov_len,
 		const struct interface *iface);
 ssize_t odhcpd_get_interface_addresses(int ifindex,
-		struct odhcpd_ipaddr *addrs, size_t cnt);
+		struct odhcpd_ipaddr **addrs);
 int odhcpd_get_interface_dns_addr(const struct interface *iface,
 		struct in6_addr *addr);
 struct interface* odhcpd_get_interface_by_name(const char *name);
diff --git a/src/router.c b/src/router.c
index f08a7b0..85ca6b0 100644
--- a/src/router.c
+++ b/src/router.c
@@ -38,7 +38,7 @@ static void sigusr1_refresh(int signal);
 static struct odhcpd_event router_event = {.uloop = {.fd = -1}, .handle_dgram = handle_icmpv6, };
 
 static FILE *fp_route = NULL;
-#define RA_IOV_LEN 6
+#define RA_IOV_LEN 7
 
 #define TIME_LEFT(t1, now) ((t1) != UINT32_MAX ? (t1) - (now) : UINT32_MAX)
 
@@ -275,7 +275,6 @@ static uint64_t send_router_advert(struct interface *iface, const struct in6_add
 		struct nd_router_advert h;
 		struct icmpv6_opt lladdr;
 		struct nd_opt_mtu mtu;
-		struct nd_opt_prefix_info prefix[sizeof(iface->ia_addr) / sizeof(*iface->ia_addr)];
 	} adv = {
 		.h = {{.icmp6_type = ND_ROUTER_ADVERT, .icmp6_code = 0}, 0, 0},
 		.lladdr = {ND_OPT_SOURCE_LINKADDR, 1, {0}},
@@ -302,7 +301,7 @@ static uint64_t send_router_advert(struct interface *iface, const struct in6_add
 	odhcpd_get_mac(iface, adv.lladdr.data);
 
 	// If not currently shutting down
-	struct odhcpd_ipaddr addrs[RELAYD_MAX_ADDRS];
+	struct odhcpd_ipaddr *addrs = NULL;
 	ssize_t ipcnt = 0;
 	uint32_t minvalid = UINT32_MAX;
 	bool default_route = false;
@@ -310,8 +309,11 @@ static uint64_t send_router_advert(struct interface *iface, const struct in6_add
 
 	// If not shutdown
 	if (iface->timer_rs.cb) {
+		size_t size = sizeof(*addrs) * iface->ia_addr_len;
+		addrs = alloca(size);
+		memcpy(addrs, iface->ia_addr, size);
+
 		ipcnt = iface->ia_addr_len;
-		memcpy(addrs, iface->ia_addr, ipcnt * sizeof(*addrs));
 
 		// Check default route
 		if (iface->default_router) {
@@ -323,14 +325,16 @@ static uint64_t send_router_advert(struct interface *iface, const struct in6_add
 			default_route = true;
 	}
 
-	// Construct Prefix Information options
-	size_t cnt = 0;
 
 	struct in6_addr dns_pref, *dns_addr = &dns_pref;
 	size_t dns_cnt = 1;
 
 	odhcpd_get_interface_dns_addr(iface, &dns_pref);
 
+	// Construct Prefix Information options
+	size_t pfxs_cnt = 0;
+	struct nd_opt_prefix_info *pfxs = NULL;
+
 	for (ssize_t i = 0; i < ipcnt; ++i) {
 		struct odhcpd_ipaddr *addr = &addrs[i];
 		uint32_t preferred = 0;
@@ -346,18 +350,25 @@ static uint64_t send_router_advert(struct interface *iface, const struct in6_add
 		}
 
 		struct nd_opt_prefix_info *p = NULL;
-		for (size_t i = 0; i < cnt; ++i) {
-			if (addr->prefix == adv.prefix[i].nd_opt_pi_prefix_len &&
-					!odhcpd_bmemcmp(&adv.prefix[i].nd_opt_pi_prefix,
+		for (size_t i = 0; i < pfxs_cnt; ++i) {
+			if (addr->prefix == pfxs[i].nd_opt_pi_prefix_len &&
+					!odhcpd_bmemcmp(&pfxs[i].nd_opt_pi_prefix,
 					&addr->addr, addr->prefix))
-				p = &adv.prefix[i];
+				p = &pfxs[i];
 		}
 
 		if (!p) {
-			if (cnt >= ARRAY_SIZE(adv.prefix))
-				break;
+			struct nd_opt_prefix_info *tmp;
 
-			p = &adv.prefix[cnt++];
+			tmp = realloc(pfxs, sizeof(*pfxs) * (pfxs_cnt + 1));
+			if (!tmp) {
+				syslog(LOG_ERR, "Realloc failed for RA prefix option on interface %s", iface->ifname);
+				continue;
+			}
+
+			pfxs = tmp;
+			p = &pfxs[pfxs_cnt++];
+			memset(p, 0, sizeof(*p));
 		}
 
 		if (addr->preferred > (uint32_t)now) {
@@ -428,8 +439,6 @@ static uint64_t send_router_advert(struct interface *iface, const struct in6_add
 		uint32_t lifetime;
 	} dns = {ND_OPT_RECURSIVE_DNS, (1 + (2 * dns_cnt)), 0, 0, 0};
 
-
-
 	// DNS Search options
 	uint8_t search_buf[256], *search_domain = iface->search;
 	size_t search_len = iface->search_len, search_padded = 0;
@@ -471,7 +480,7 @@ static uint64_t send_router_advert(struct interface *iface, const struct in6_add
 		uint8_t flags;
 		uint32_t lifetime;
 		uint32_t addr[4];
-	} routes[RELAYD_MAX_PREFIXES];
+	} *tmp, *routes = NULL;
 
 	for (ssize_t i = 0; i < ipcnt; ++i) {
 		struct odhcpd_ipaddr *addr = &addrs[i];
@@ -485,6 +494,15 @@ static uint64_t send_router_advert(struct interface *iface, const struct in6_add
 			addr->addr.s6_addr32[1] = 0;
 		}
 
+		tmp = realloc(routes, sizeof(*routes) * (routes_cnt + 1));
+		if (!tmp) {
+			syslog(LOG_ERR, "Realloc failed for RA route option on interface %s", iface->ifname);
+			continue;
+		}
+
+		routes = tmp;
+
+		memset(&routes[routes_cnt], 0, sizeof(*routes));
 		routes[routes_cnt].type = ND_OPT_ROUTE_INFO;
 		routes[routes_cnt].len = sizeof(*routes) / 8;
 		routes[routes_cnt].prefix = addr->dprefix;
@@ -512,8 +530,9 @@ static uint64_t send_router_advert(struct interface *iface, const struct in6_add
 	};
 
 	struct iovec iov[RA_IOV_LEN] = {
-			{&adv, (uint8_t*)&adv.prefix[cnt] - (uint8_t*)&adv},
-			{&routes, routes_cnt * sizeof(*routes)},
+			{&adv, sizeof(adv)},
+			{pfxs, pfxs_cnt * sizeof(*pfxs)},
+			{routes, routes_cnt * sizeof(*routes)},
 			{&dns, (dns_cnt) ? sizeof(dns) : 0},
 			{dns_addr, dns_cnt * sizeof(*dns_addr)},
 			{search, search->len * 8},
@@ -526,6 +545,9 @@ static uint64_t send_router_advert(struct interface *iface, const struct in6_add
 	odhcpd_send(router_event.uloop.fd,
 			&dest, iov, ARRAY_SIZE(iov), iface);
 
+	free(pfxs);
+	free(routes);
+
 	return msecs;
 }