1 files changed, 117 insertions, 3 deletions

diff --git a/src/dhcpv6-ia.c b/src/dhcpv6-ia.c
index 41c9f30..1fbed44 100644
--- a/src/dhcpv6-ia.c
+++ b/src/dhcpv6-ia.c
@@ -288,6 +288,26 @@ struct write_ctxt {
 	int buf_idx;
 };
 
+static void dhcpv6_write_ia_addrhosts(struct in6_addr *addr, int prefix, _unused uint32_t pref,
+				_unused uint32_t valid, void *arg)
+{
+	struct write_ctxt *ctxt = (struct write_ctxt *)arg;
+	char ipbuf[INET6_ADDRSTRLEN];
+
+	if ((ctxt->c->flags & OAF_DHCPV6_NA) && ctxt->c->hostname &&
+	    !(ctxt->c->flags & OAF_BROKEN_HOSTNAME)) {
+		inet_ntop(AF_INET6, addr, ipbuf, sizeof(ipbuf) - 1);
+		fputs(ipbuf, ctxt->fp);
+
+		char b[256];
+		if (dn_expand(ctxt->iface->search, ctxt->iface->search + ctxt->iface->search_len,
+				ctxt->iface->search, b, sizeof(b)) > 0)
+			fprintf(ctxt->fp, "\t%s.%s", ctxt->c->hostname, b);
+
+		fprintf(ctxt->fp, "\t%s\n", ctxt->c->hostname);
+	}
+}
+
 static void dhcpv6_write_ia_addr(struct in6_addr *addr, int prefix, _unused uint32_t pref,
 				_unused uint32_t valid, void *arg)
 {
@@ -314,6 +334,98 @@ static void dhcpv6_write_ia_addr(struct in6_addr *addr, int prefix, _unused uint
 					"%s/%d ", ipbuf, prefix);
 }
 
+static void dhcpv6_ia_write_hostsfile(time_t now)
+{
+	struct write_ctxt ctxt;
+
+	unsigned hostsfile_strlen = strlen(config.dhcp_hostsfile) + 1;
+	unsigned tmp_hostsfile_strlen = hostsfile_strlen + 1; /* space for . */
+	char *tmp_hostsfile = alloca(tmp_hostsfile_strlen);
+
+	char *dir_hostsfile;
+	char *base_hostsfile;
+	char *pdir_hostsfile;
+	char *pbase_hostsfile;
+
+	int fd, ret;
+
+	dir_hostsfile = strndup(config.dhcp_hostsfile, hostsfile_strlen);
+	base_hostsfile = strndup(config.dhcp_hostsfile, hostsfile_strlen);
+
+	pdir_hostsfile = dirname(dir_hostsfile);
+	pbase_hostsfile = basename(base_hostsfile);
+
+	snprintf(tmp_hostsfile, tmp_hostsfile_strlen, "%s/.%s", pdir_hostsfile, pbase_hostsfile);
+
+	free(dir_hostsfile);
+	free(base_hostsfile);
+
+	fd = open(tmp_hostsfile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
+	if (fd < 0)
+		return;
+
+	ret = lockf(fd, F_LOCK, 0);
+	if (ret < 0) {
+		close(fd);
+		return;
+	}
+
+	if (ftruncate(fd, 0) < 0) {}
+
+	ctxt.fp = fdopen(fd, "w");
+	if (!ctxt.fp) {
+		close(fd);
+		return;
+	}
+
+	avl_for_each_element(&interfaces, ctxt.iface, avl) {
+		if (ctxt.iface->dhcpv6 != MODE_SERVER &&
+				ctxt.iface->dhcpv4 != MODE_SERVER)
+			continue;
+
+		if (ctxt.iface->dhcpv6 == MODE_SERVER) {
+			list_for_each_entry(ctxt.c, &ctxt.iface->ia_assignments, head) {
+				if (!(ctxt.c->flags & OAF_BOUND) || ctxt.c->managed_size < 0)
+					continue;
+
+				if (INFINITE_VALID(ctxt.c->valid_until) || ctxt.c->valid_until > now)
+					dhcpv6_ia_enum_addrs(ctxt.iface, ctxt.c, now,
+								dhcpv6_write_ia_addrhosts, &ctxt);
+			}
+		}
+
+		if (ctxt.iface->dhcpv4 == MODE_SERVER) {
+			struct dhcp_assignment *c;
+
+			list_for_each_entry(c, &ctxt.iface->dhcpv4_assignments, head) {
+				if (!(c->flags & OAF_BOUND))
+					continue;
+
+				char ipbuf[INET6_ADDRSTRLEN];
+				struct in_addr addr = {.s_addr = c->addr};
+				inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
+
+				if (c->hostname && !(c->flags & OAF_BROKEN_HOSTNAME)) {
+					fputs(ipbuf, ctxt.fp);
+
+					char b[256];
+
+					if (dn_expand(ctxt.iface->search,
+							ctxt.iface->search + ctxt.iface->search_len,
+							ctxt.iface->search, b, sizeof(b)) > 0)
+						fprintf(ctxt.fp, "\t%s.%s", c->hostname, b);
+
+					fprintf(ctxt.fp, "\t%s\n", c->hostname);
+				}
+			}
+		}
+	}
+
+	fclose(ctxt.fp);
+
+	rename(tmp_hostsfile, config.dhcp_hostsfile);
+}
+
 void dhcpv6_ia_write_statefile(void)
 {
 	struct write_ctxt ctxt;
@@ -457,9 +569,13 @@ void dhcpv6_ia_write_statefile(void)
 		uint8_t newmd5[16];
 		md5_end(newmd5, &ctxt.md5);
 
+		rename(tmp_statefile, config.dhcp_statefile);
+
 		if (memcmp(newmd5, statemd5, sizeof(newmd5))) {
 			memcpy(statemd5, newmd5, sizeof(statemd5));
-			rename(tmp_statefile, config.dhcp_statefile);
+
+			if (config.dhcp_hostsfile)
+				dhcpv6_ia_write_hostsfile(now);
 
 			if (config.dhcp_cb) {
 				char *argv[2] = {config.dhcp_cb, NULL};
@@ -468,8 +584,6 @@ void dhcpv6_ia_write_statefile(void)
 					_exit(128);
 				}
 			}
-		} else {
-			unlink(tmp_statefile);
 		}
 	}
 }