--- /dev/null
+/*
+ * rrdns - Rapid Reverse DNS lookup plugin for the UBUS RPC server
+ *
+ * Copyright (C) 2016 Jo-Philipp Wich <jow@openwrt.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <arpa/nameser.h>
+#include <arpa/inet.h>
+
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include <resolv.h>
+
+#include <libubox/avl.h>
+#include <libubox/usock.h>
+#include <libubox/uloop.h>
+
+#include <rpcd/plugin.h>
+
+#include "rrdns.h"
+
+
+enum {
+ RPC_L_ADDRS,
+ RPC_L_TIMEOUT,
+ RPC_L_SERVER,
+ RPC_L_PORT,
+ RPC_L_LIMIT,
+ __RPC_L_MAX,
+};
+
+static const struct blobmsg_policy rpc_lookup_policy[__RPC_L_MAX] = {
+ [RPC_L_ADDRS] = { .name = "addrs", .type = BLOBMSG_TYPE_ARRAY },
+ [RPC_L_TIMEOUT] = { .name = "timeout", .type = BLOBMSG_TYPE_INT32 },
+ [RPC_L_SERVER] = { .name = "server", .type = BLOBMSG_TYPE_STRING },
+ [RPC_L_PORT] = { .name = "port", .type = BLOBMSG_TYPE_INT16 },
+ [RPC_L_LIMIT] = { .name = "limit", .type = BLOBMSG_TYPE_INT32 },
+};
+
+
+static int
+rrdns_cmp_id(const void *k1, const void *k2, void *ptr)
+{
+ const uint16_t *id1 = k1, *id2 = k2;
+ return (*id1 - *id2);
+}
+
+static int
+rrdns_cmp_addr(const void *k1, const void *k2, void *ptr)
+{
+ const struct in6_addr *a1 = k1, *a2 = k2;
+ return memcmp(a1, a2, sizeof(*a1));
+}
+
+static int
+rrdns_parse_response(struct rrdns_context *rctx)
+{
+ int n, len;
+ uint16_t id;
+ struct rrdns_request *req;
+ unsigned char res[512];
+ char buf[INET6_ADDRSTRLEN], dname[MAXDNAME];
+ HEADER *hdr;
+ ns_msg handle;
+ ns_rr rr;
+
+ len = recv(rctx->socket.fd, res, sizeof(res), 0);
+
+ if (len < sizeof(*hdr))
+ return -ENODATA;
+
+ hdr = (HEADER *)res;
+ id = hdr->id;
+ req = avl_find_element(&rctx->request_ids, &id, req, by_id);
+
+ if (!req)
+ return -ENOENT;
+
+ avl_delete(&rctx->request_ids, &req->by_id);
+
+ if (ns_initparse(res, len, &handle))
+ return -EINVAL;
+
+ for (n = 0; n < ns_msg_count(handle, ns_s_an); n++) {
+ if (ns_parserr(&handle, ns_s_an, n, &rr))
+ return -EINVAL;
+
+ if (ns_rr_type(rr) != ns_t_ptr)
+ continue;
+
+ if (ns_name_uncompress(ns_msg_base(handle), ns_msg_end(handle),
+ ns_rr_rdata(rr), dname, sizeof(dname)) < 0)
+ return -EINVAL;
+
+ inet_ntop(req->family, &req->addr, buf, sizeof(buf));
+ blobmsg_add_string(&rctx->blob, buf, dname);
+ }
+
+ return 0;
+}
+
+static int
+rrdns_next_query(struct rrdns_context *rctx)
+{
+ const char *addr = NULL, *hex = "0123456789abcdef";
+ struct rrdns_request *req;
+ int i, alen, family;
+ char *p, dname[73];
+
+ union {
+ unsigned char uchar[4];
+ struct in6_addr in6;
+ struct in_addr in;
+ } a = { };
+
+ union {
+ unsigned char buf[512];
+ HEADER hdr;
+ } msg;
+
+ if (rctx->addr_rem > 0 &&
+ blob_pad_len(rctx->addr_cur) <= rctx->addr_rem &&
+ blob_pad_len(rctx->addr_cur) >= sizeof(struct blob_attr)) {
+
+ addr = blobmsg_get_string(rctx->addr_cur);
+ rctx->addr_rem -= blob_pad_len(rctx->addr_cur);
+ rctx->addr_cur = blob_next(rctx->addr_cur);
+ }
+
+ if (!addr)
+ return 0;
+
+ if (inet_pton(AF_INET6, addr, &a.in6)) {
+ memset(dname, 0, sizeof(dname));
+
+ for (i = 0, p = dname; i < 16; i++) {
+ *p++ = hex[a.in6.s6_addr[15-i] % 16];
+ *p++ = '.';
+ *p++ = hex[a.in6.s6_addr[15-i] / 16];
+ *p++ = '.';
+ }
+
+ p += snprintf(p, p - dname - 1, "ip6.arpa");
+
+ family = AF_INET6;
+ alen = p - dname;
+ }
+ else if (inet_pton(AF_INET, addr, &a.in)) {
+ family = AF_INET;
+ alen = snprintf(dname, sizeof(dname), "%u.%u.%u.%u.in-addr.arpa",
+ a.uchar[3], a.uchar[2], a.uchar[1], a.uchar[0]);
+ }
+ else {
+ return -EINVAL;
+ }
+
+ alen = res_mkquery(QUERY, dname, C_IN, T_PTR, NULL, 0, NULL,
+ msg.buf, sizeof(msg.buf));
+
+ if (alen < 0)
+ return alen;
+
+ if (avl_find(&rctx->request_addrs, &a.in6))
+ return -ENOTUNIQ;
+
+ if (send(rctx->socket.fd, msg.buf, alen, 0) != alen)
+ return -errno;
+
+ req = calloc(1, sizeof(*req));
+
+ if (!req)
+ return -ENOMEM;
+
+ req->id = msg.hdr.id;
+ req->by_id.key = &req->id;
+ avl_insert(&rctx->request_ids, &req->by_id);
+
+ req->family = family;
+ req->addr.in6 = a.in6;
+ req->by_addr.key = &req->addr.in6;
+ avl_insert(&rctx->request_addrs, &req->by_addr);
+
+ return 0;
+}
+
+static void
+rdns_shutdown(struct rrdns_context *rctx)
+{
+ struct rrdns_request *req, *tmp;
+
+ uloop_timeout_cancel(&rctx->timeout);
+ uloop_fd_delete(&rctx->socket);
+
+ close(rctx->socket.fd);
+
+ ubus_send_reply(rctx->context, &rctx->request, rctx->blob.head);
+ ubus_complete_deferred_request(rctx->context, &rctx->request,
+ UBUS_STATUS_OK);
+
+ avl_remove_all_elements(&rctx->request_addrs, req, by_addr, tmp)
+ free(req);
+
+ blob_buf_free(&rctx->blob);
+ free(rctx);
+}
+
+static void
+rrdns_handle_timeout(struct uloop_timeout *utm)
+{
+ struct rrdns_context *rctx =
+ container_of(utm, struct rrdns_context, timeout);
+
+ rdns_shutdown(rctx);
+}
+
+static void
+rrdns_handle_response(struct uloop_fd *ufd, unsigned int ev)
+{
+ struct rrdns_context *rctx =
+ container_of(ufd, struct rrdns_context, socket);
+
+ int err = rrdns_parse_response(rctx);
+
+ if (err != -ENODATA && err != -ENOENT)
+ rrdns_next_query(rctx);
+
+ if (avl_is_empty(&rctx->request_ids))
+ rdns_shutdown(rctx);
+}
+
+static char *
+rrdns_find_nameserver(void)
+{
+ static char line[2*INET6_ADDRSTRLEN];
+ struct in6_addr in6;
+ FILE *resolvconf;
+ char *p;
+
+ resolvconf = fopen("/etc/resolv.conf", "r");
+
+ if (!resolvconf)
+ return NULL;
+
+ while (fgets(line, sizeof(line), resolvconf)) {
+ p = strtok(line, " \t");
+
+ if (!p || strcmp(p, "nameserver"))
+ continue;
+
+ p = strtok(NULL, " \t\r\n");
+
+ if (!p)
+ continue;
+
+ if (!inet_pton(AF_INET6, p, &in6) && !inet_pton(AF_INET, p, &in6))
+ continue;
+
+ fclose(resolvconf);
+ return p;
+ }
+
+ fclose(resolvconf);
+ return NULL;
+}
+
+static int
+rpc_rrdns_lookup(struct ubus_context *ctx, struct ubus_object *obj,
+ struct ubus_request_data *req, const char *method,
+ struct blob_attr *msg)
+{
+ int port = 53, limit = RRDNS_DEF_LIMIT, timeout = RRDNS_DEF_TIMEOUT;
+ struct blob_attr *tb[__RPC_L_MAX];
+ struct rrdns_context *rctx;
+ const char *server = NULL;
+
+ blobmsg_parse(rpc_lookup_policy, __RPC_L_MAX, tb,
+ blob_data(msg), blob_len(msg));
+
+ if (tb[RPC_L_PORT])
+ port = blobmsg_get_u16(tb[RPC_L_PORT]);
+
+ if (tb[RPC_L_LIMIT])
+ limit = blobmsg_get_u32(tb[RPC_L_LIMIT]);
+
+ if (tb[RPC_L_TIMEOUT])
+ timeout = blobmsg_get_u32(tb[RPC_L_TIMEOUT]);
+
+ if (tb[RPC_L_SERVER])
+ server = blobmsg_get_string(tb[RPC_L_SERVER]);
+
+
+ if (!tb[RPC_L_ADDRS])
+ return UBUS_STATUS_INVALID_ARGUMENT;
+
+ if (port <= 0)
+ return UBUS_STATUS_INVALID_ARGUMENT;
+
+ if (limit <= 0 || limit > RRDNS_MAX_LIMIT)
+ return UBUS_STATUS_INVALID_ARGUMENT;
+
+ if (timeout <= 0 || timeout > RRDNS_MAX_TIMEOUT)
+ return UBUS_STATUS_INVALID_ARGUMENT;
+
+
+ if (!server || !*server)
+ server = rrdns_find_nameserver();
+
+ if (!server)
+ return UBUS_STATUS_NOT_FOUND;
+
+ rctx = calloc(1, sizeof(*rctx));
+
+ if (!rctx)
+ return UBUS_STATUS_UNKNOWN_ERROR;
+
+ rctx->socket.fd = usock(USOCK_UDP, server, usock_port(port));
+
+ if (rctx->socket.fd < 0) {
+ free(rctx);
+ return UBUS_STATUS_UNKNOWN_ERROR;
+ }
+
+ rctx->context = ctx;
+ rctx->addr_cur = blobmsg_data(tb[RPC_L_ADDRS]);
+ rctx->addr_rem = blobmsg_data_len(tb[RPC_L_ADDRS]);
+
+ avl_init(&rctx->request_ids, rrdns_cmp_id, false, NULL);
+ avl_init(&rctx->request_addrs, rrdns_cmp_addr, false, NULL);
+
+ rctx->timeout.cb = rrdns_handle_timeout;
+ uloop_timeout_set(&rctx->timeout, timeout);
+
+ rctx->socket.cb = rrdns_handle_response;
+ uloop_fd_add(&rctx->socket, ULOOP_READ);
+
+ blob_buf_init(&rctx->blob, 0);
+
+ while (limit--)
+ rrdns_next_query(rctx);
+
+ ubus_defer_request(ctx, req, &rctx->request);
+
+ return UBUS_STATUS_OK;
+}
+
+
+static int
+rpc_rrdns_api_init(const struct rpc_daemon_ops *o, struct ubus_context *ctx)
+{
+ static const struct ubus_method rrdns_methods[] = {
+ UBUS_METHOD("lookup", rpc_rrdns_lookup, rpc_lookup_policy),
+ };
+
+ static struct ubus_object_type rrdns_type =
+ UBUS_OBJECT_TYPE("rpcd-rrdns", rrdns_methods);
+
+ static struct ubus_object obj = {
+ .name = "network.rrdns",
+ .type = &rrdns_type,
+ .methods = rrdns_methods,
+ .n_methods = ARRAY_SIZE(rrdns_methods),
+ };
+
+ return ubus_add_object(ctx, &obj);
+}
+
+struct rpc_plugin rpc_plugin = {
+ .init = rpc_rrdns_api_init
+};
projects / project / luci.git / commitdiff