Implement basic lease management

1 files changed, 210 insertions, 0 deletions

diff --git a/lease.c b/lease.c
new file mode 100644
index 0000000..936a4a8
--- /dev/null
+++ b/lease.c
@@ -0,0 +1,210 @@
+#define _POSIX_C_SOURCE 200809L
+
+#include <arpa/inet.h>
+#include <inttypes.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <time.h>
+
+#include "dbg.h"
+#include "khash.h"
+#include "lease.h"
+#include "netlink.h"
+#include "radix-trie.h"
+#include "random.h"
+
+static struct ip_pool pools;
+static time_t gexpires;
+
+KHASH_MAP_INIT_WGKEY(leaseht, struct wg_dynamic_lease *)
+khash_t(leaseht) * leases_ht;
+
+static uint64_t totall_ipv6;
+static uint32_t totalh_ipv6, total_ipv4;
+
+static time_t get_monotonic_time()
+{
+	struct timespec monotime;
+#ifdef __linux__
+	/* in linux 4.17, CLOCK_MONOTONIC was changed to be like CLOCK_BOOTTIME,
+	 * see https://git.kernel.org/torvalds/c/d6ed449, but glibc's wrapper
+	 * seems to still have the old behavior
+	 */
+	if (clock_gettime(CLOCK_BOOTTIME, &monotime))
+		fatal("clock_gettime(CLOCK_BOOTTIME)");
+#else
+	/* CLOCK_MONOTONIC works on openbsd, but apparently not (yet) on
+	 * freebsd: https://lists.freebsd.org/pipermail/freebsd-hackers/2018-June/052899.html
+	 */
+	if (clock_gettime(CLOCK_MONOTONIC, &monotime))
+		fatal("clock_gettime(CLOCK_MONOTONIC)");
+
+#endif
+	/* TODO: what about darwin? */
+
+	return monotime.tv_sec;
+}
+
+void leases_init(char *fname)
+{
+	UNUSED(fname); /* TODO: open file and initialize from it */
+
+	leases_ht = kh_init(leaseht);
+
+	ipp_init(&pools);
+
+	/* TODO: initialize pools properly from routes */
+	struct in_addr pool1_v4, pool2_v4;
+	struct in6_addr pool1_v6, pool2_v6;
+	inet_pton(AF_INET, "192.168.4.0", &pool1_v4);
+	inet_pton(AF_INET, "192.168.73.0", &pool2_v4);
+	inet_pton(AF_INET6, "2001:db8:1234::", &pool1_v6);
+	inet_pton(AF_INET6, "2001:db8:7777::", &pool2_v6);
+
+	ipp_addpool_v4(&pools, &pool1_v4, 28);
+	ipp_addpool_v4(&pools, &pool2_v4, 27);
+	ipp_addpool_v6(&pools, &pool1_v6, 124);
+	ipp_addpool_v6(&pools, &pool2_v6, 124);
+
+	total_ipv4 = ipp_gettotal_v4(&pools);
+	totall_ipv6 = ipp_gettotal_v6(&pools, &totalh_ipv6);
+}
+
+void leases_free()
+{
+	kh_destroy(leaseht, leases_ht);
+	ipp_free(&pools);
+}
+
+struct wg_dynamic_lease *new_lease(wg_key pubkey, uint32_t leasetime,
+				   struct in_addr *ipv4, struct in6_addr *ipv6,
+				   time_t *expires)
+{
+	struct wg_dynamic_lease *lease, *parent;
+	uint64_t index_low;
+	uint32_t index, index_high;
+	struct timespec tp;
+	khiter_t k;
+	int ret;
+
+	lease = malloc(sizeof *lease);
+	if (!lease)
+		fatal("malloc()");
+
+	if (!ipv4 || ipv4->s_addr) {
+		if (total_ipv4 == 0)
+			return NULL;
+
+		--total_ipv4;
+	}
+	if (!ipv6 || !IN6_IS_ADDR_UNSPECIFIED(ipv6)) {
+		if (totalh_ipv6 == 0 && totall_ipv6 == 0) {
+			if (!ipv4 || ipv4->s_addr)
+				++total_ipv4;
+
+			return NULL;
+		}
+
+		if (totall_ipv6 == 0)
+			--totalh_ipv6;
+
+		--totall_ipv6;
+	}
+
+	if (!ipv4 || ipv4->s_addr) {
+		if (!ipv4) {
+			index = random_bounded(total_ipv4);
+			debug("new_lease(v4): %u of %u\n", index, total_ipv4);
+			ipp_addnth_v4(&pools, &lease->ipv4, index);
+		} else {
+			if (ipp_add_v4(&pools, ipv4, 32))
+				return NULL;
+			memcpy(&lease->ipv4, ipv4, sizeof *ipv4);
+		}
+	}
+	if (!ipv6 || !IN6_IS_ADDR_UNSPECIFIED(ipv6)) {
+		if (!ipv6) {
+			if (totalh_ipv6 > 0) {
+				index_low = random_bounded(UINT64_MAX);
+				if (totall_ipv6 - index_low > totall_ipv6)
+					--totalh_ipv6;
+
+				index_high = random_bounded(totalh_ipv6);
+			} else {
+				index_low = random_bounded(totall_ipv6);
+				index_high = 0;
+			}
+			debug("new_lease(v6): %u:%ju of %u:%ju\n", index_high,
+			      index_low, totalh_ipv6, totall_ipv6);
+
+			ipp_addnth_v6(&pools, &lease->ipv6, index_low,
+				      index_high);
+		} else {
+			if (ipp_add_v6(&pools, ipv6, 128))
+				return NULL; /* TODO: free ipv4 addr */
+			memcpy(&lease->ipv6, ipv6, sizeof *ipv6);
+		}
+	}
+
+	if (clock_gettime(CLOCK_REALTIME, &tp))
+		fatal("clock_gettime(CLOCK_REALTIME)");
+
+	lease->start_real = tp.tv_sec;
+	lease->start_mono = get_monotonic_time();
+	lease->leasetime = leasetime;
+	lease->next = NULL;
+
+	k = kh_put(leaseht, leases_ht, pubkey, &ret);
+	if (ret < 0) {
+		die("kh_put()");
+	} else if (ret == 0) {
+		parent = kh_value(leases_ht, k);
+		while (parent->next)
+			parent = parent->next;
+
+		parent->next = lease;
+	} else {
+		kh_value(leases_ht, k) = lease;
+	}
+
+	if (lease->start_mono < gexpires)
+		gexpires = lease->start_mono;
+
+	*expires = gexpires;
+
+	/* TODO: add record to file */
+
+	return lease;
+}
+
+struct wg_dynamic_lease *get_leases(wg_key pubkey)
+{
+	khiter_t k = kh_get(leaseht, leases_ht, pubkey);
+
+	if (k == kh_end(leases_ht))
+		return NULL;
+	else
+		return kh_val(leases_ht, k);
+}
+
+bool extend_lease(struct wg_dynamic_lease *lease, uint32_t leasetime,
+		  time_t *expires)
+{
+	UNUSED(lease);
+	UNUSED(leasetime);
+	UNUSED(expires);
+	return false;
+}
+
+time_t leases_refresh()
+{
+	/* TODO: remove expired leases */
+	return gexpires;
+}
+
+void leases_update_pools(int fd)
+{
+	UNUSED(fd);
+}