Adding upstream version 5.6.0.upstream/5.6.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 524 insertions, 0 deletions

diff --git a/modules/dnstap/dnstap.c b/modules/dnstap/dnstap.c
new file mode 100644
index 0000000..7572667
--- /dev/null
+++ b/modules/dnstap/dnstap.c
@@ -0,0 +1,524 @@
+/*
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ * @file dnstap.c
+ * @brief dnstap based query logging support
+ *
+ */
+
+#include "lib/module.h"
+#include "modules/dnstap/dnstap.pb-c.h"
+
+#include "contrib/cleanup.h"
+#include "daemon/session.h"
+#include "daemon/worker.h"
+#include "lib/layer.h"
+#include "lib/resolve.h"
+
+#include <ccan/json/json.h>
+#include <fstrm.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <uv.h>
+
+#define DEBUG_MSG(fmt, ...) kr_log_debug(DNSTAP, fmt, ##__VA_ARGS__);
+#define ERROR_MSG(fmt, ...) kr_log_error(DNSTAP, fmt, ##__VA_ARGS__);
+#define CFG_SOCK_PATH "socket_path"
+#define CFG_IDENTITY_STRING "identity"
+#define CFG_VERSION_STRING "version"
+#define CFG_LOG_CLIENT_PKT "client"
+#define CFG_LOG_QR_PKT "log_queries"
+#define CFG_LOG_RESP_PKT "log_responses"
+#define CFG_LOG_TCP_RTT "log_tcp_rtt"
+#define DEFAULT_SOCK_PATH "/tmp/dnstap.sock"
+#define DNSTAP_CONTENT_TYPE "protobuf:dnstap.Dnstap"
+#define DNSTAP_INITIAL_BUF_SIZE         256
+
+#define auto_destroy_uopts __attribute__((cleanup(fstrm_unix_writer_options_destroy)))
+#define auto_destroy_wopts __attribute__((cleanup(fstrm_writer_options_destroy)))
+
+/*
+ * Internal processing phase
+ * Distinguishes whether query or response should be processed
+ */
+enum dnstap_log_phase {
+	CLIENT_QUERY_PHASE = 0,
+	CLIENT_RESPONSE_PHASE,
+};
+
+/* Internal data structure */
+struct dnstap_data {
+	char *identity;
+	size_t identity_len;
+	char *version;
+	size_t version_len;
+	bool log_qr_pkt;
+	bool log_resp_pkt;
+	bool log_tcp_rtt;
+	struct fstrm_iothr *iothread;
+	struct fstrm_iothr_queue *ioq;
+};
+
+/*
+ * dt_pack packs the dnstap message for transport
+ * https://gitlab.nic.cz/knot/knot-dns/blob/master/src/contrib/dnstap/dnstap.c#L24
+ * */
+uint8_t* dt_pack(const Dnstap__Dnstap *d, uint8_t **buf, size_t *sz)
+{
+	ProtobufCBufferSimple sbuf = { { NULL } };
+
+	sbuf.base.append = protobuf_c_buffer_simple_append;
+	sbuf.len = 0;
+	sbuf.alloced = DNSTAP_INITIAL_BUF_SIZE;
+	sbuf.data = malloc(sbuf.alloced);
+	if (sbuf.data == NULL) {
+		return NULL;
+	}
+	sbuf.must_free_data = true;
+
+	*sz = dnstap__dnstap__pack_to_buffer(d, (ProtobufCBuffer *) &sbuf);
+	*buf = sbuf.data;
+	return *buf;
+}
+
+/* set_address fills in address detail in dnstap_message
+ * https://gitlab.nic.cz/knot/knot-dns/blob/master/src/contrib/dnstap/message.c#L28
+ */
+static void set_address(const struct sockaddr *sockaddr,
+		ProtobufCBinaryData   *addr,
+		protobuf_c_boolean    *has_addr,
+		uint32_t              *port,
+		protobuf_c_boolean    *has_port) {
+	const char *saddr = kr_inaddr(sockaddr);
+	if (saddr == NULL) {
+		*has_addr = false;
+		*has_port = false;
+		return;
+	}
+
+	addr->data = (uint8_t *)(saddr);
+	addr->len = kr_inaddr_len(sockaddr);
+	*has_addr = true;
+	*port = kr_inaddr_port(sockaddr);
+	*has_port = true;
+}
+
+#ifndef HAS_TCP_INFO
+	/* TCP RTT: not portable; not sure where else it might work. */
+	#define HAS_TCP_INFO __linux__
+#endif
+#if HAS_TCP_INFO
+/** Fill a tcp_info or return kr_error(). */
+static int get_tcp_info(const struct kr_request *req, struct tcp_info *info)
+{
+	if(kr_fails_assert(req && info))
+		return kr_error(EINVAL);
+	if (!req->qsource.dst_addr || !req->qsource.flags.tcp) /* not TCP-based */
+		return -abs(ENOENT);
+	/* First obtain the file-descriptor. */
+	uv_handle_t *h = session_get_handle(worker_request_get_source_session(req));
+	uv_os_fd_t fd;
+	int ret = uv_fileno(h, &fd);
+	if (ret)
+		return kr_error(ret);
+
+	socklen_t tcp_info_length = sizeof(*info);
+	if (getsockopt(fd, SOL_TCP, TCP_INFO, info, &tcp_info_length))
+		return kr_error(errno);
+	return kr_ok();
+}
+#endif
+
+/* dnstap_log prepares dnstap message and sends it to fstrm
+ *
+ * Return codes are kr_error(E*) and unused for now.
+ */
+static int dnstap_log(kr_layer_t *ctx, enum dnstap_log_phase phase) {
+	const struct kr_request *req = ctx->req;
+	const struct kr_module *module = ctx->api->data;
+	const struct kr_rplan *rplan = &req->rplan;
+	const struct dnstap_data *dnstap_dt = module->data;
+
+	if (!req->qsource.addr) {
+		return kr_ok();
+	}
+
+	/* check if we have a valid iothread */
+	if (!dnstap_dt->iothread || !dnstap_dt->ioq) {
+		DEBUG_MSG("dnstap_dt->iothread or dnstap_dt->ioq is NULL\n");
+		return kr_error(EFAULT);
+	}
+
+	/* Create dnstap message */
+	Dnstap__Message m;
+	Dnstap__Dnstap dnstap = DNSTAP__DNSTAP__INIT;
+	dnstap.type = DNSTAP__DNSTAP__TYPE__MESSAGE;
+	dnstap.message = &m;
+
+	memset(&m, 0, sizeof(m));
+
+	m.base.descriptor = &dnstap__message__descriptor;
+
+	if (req->qsource.addr) {
+		set_address(req->qsource.addr,
+				&m.query_address,
+				&m.has_query_address,
+				&m.query_port,
+				&m.has_query_port);
+	}
+
+	if (req->qsource.dst_addr) {
+		if (req->qsource.flags.http) {
+			m.socket_protocol = DNSTAP__SOCKET_PROTOCOL__DOH;
+		} else if (req->qsource.flags.tls) {
+			m.socket_protocol = DNSTAP__SOCKET_PROTOCOL__DOT;
+		} else if (req->qsource.flags.tcp) {
+			m.socket_protocol = DNSTAP__SOCKET_PROTOCOL__TCP;
+		} else {
+			m.socket_protocol = DNSTAP__SOCKET_PROTOCOL__UDP;
+		}
+		m.has_socket_protocol = true;
+
+		set_address(req->qsource.dst_addr,
+				&m.response_address,
+				&m.has_response_address,
+				&m.response_port,
+				&m.has_response_port);
+		switch (req->qsource.dst_addr->sa_family) {
+			case AF_INET:
+				m.socket_family = DNSTAP__SOCKET_FAMILY__INET;
+				m.has_socket_family = true;
+				break;
+			case AF_INET6:
+				m.socket_family = DNSTAP__SOCKET_FAMILY__INET6;
+				m.has_socket_family = true;
+				break;
+		}
+	}
+
+	char dnstap_extra_buf[24];
+	if (phase == CLIENT_QUERY_PHASE) {
+		m.type = DNSTAP__MESSAGE__TYPE__CLIENT_QUERY;
+
+		if (dnstap_dt->log_qr_pkt) {
+			const knot_pkt_t *qpkt = req->qsource.packet;
+			m.has_query_message = qpkt != NULL;
+			if (qpkt != NULL) {
+				m.query_message.len = qpkt->size;
+				m.query_message.data = qpkt->wire;
+			}
+		}
+
+		/* set query time to the timestamp of the first kr_query */
+		if (rplan->initial) {
+			struct kr_query *first = rplan->initial;
+
+			m.query_time_sec = first->timestamp.tv_sec;
+			m.has_query_time_sec = true;
+			m.query_time_nsec = first->timestamp.tv_usec * 1000;
+			m.has_query_time_nsec = true;
+		}
+#if HAS_TCP_INFO
+		struct tcp_info ti = { 0 };
+		if (dnstap_dt->log_tcp_rtt && get_tcp_info(req, &ti) == kr_ok()) {
+			int len = snprintf(dnstap_extra_buf, sizeof(dnstap_extra_buf),
+						"rtt=%u\n", (unsigned)ti.tcpi_rtt);
+			if (len < sizeof(dnstap_extra_buf)) {
+				dnstap.extra.data = (uint8_t *)dnstap_extra_buf;
+				dnstap.extra.len = len;
+				dnstap.has_extra = true;
+			}
+		}
+#else
+		(void)dnstap_extra_buf;
+#endif
+	} else if (phase == CLIENT_RESPONSE_PHASE) {
+		m.type = DNSTAP__MESSAGE__TYPE__CLIENT_RESPONSE;
+
+		/* current time */
+		struct timeval now;
+		gettimeofday(&now, NULL);
+
+		if (dnstap_dt->log_resp_pkt) {
+			const knot_pkt_t *rpkt = req->answer;
+			m.has_response_message = rpkt != NULL;
+			if (rpkt != NULL) {
+				m.response_message.len = rpkt->size;
+				m.response_message.data = rpkt->wire;
+			}
+		}
+
+		/* Set response time to now */
+		m.response_time_sec = now.tv_sec;
+		m.has_response_time_sec = true;
+		m.response_time_nsec = now.tv_usec * 1000;
+		m.has_response_time_nsec = true;
+	}
+
+	if (dnstap_dt->identity) {
+		dnstap.identity.data = (uint8_t*)dnstap_dt->identity;
+		dnstap.identity.len = dnstap_dt->identity_len;
+		dnstap.has_identity = true;
+	}
+
+	if (dnstap_dt->version) {
+		dnstap.version.data = (uint8_t*)dnstap_dt->version;
+		dnstap.version.len = dnstap_dt->version_len;
+		dnstap.has_version = true;
+	}
+
+	/* Pack the message */
+	uint8_t *frame = NULL;
+	size_t size = 0;
+	dt_pack(&dnstap, &frame, &size);
+	if (!frame) {
+		return kr_error(ENOMEM);
+	}
+
+	/* Submit a request to send message to fstrm_iothr*/
+	fstrm_res res = fstrm_iothr_submit(dnstap_dt->iothread, dnstap_dt->ioq, frame, size,
+			fstrm_free_wrapper, NULL);
+	if (res != fstrm_res_success) {
+		DEBUG_MSG("Error submitting dnstap message to iothr\n");
+		free(frame);
+		return kr_error(EBUSY);
+	}
+
+	return kr_ok();
+}
+
+/* dnstap_log_query prepares dnstap CLIENT_QUERY message and sends it to fstrm */
+static int dnstap_log_query(kr_layer_t *ctx) {
+	dnstap_log(ctx, CLIENT_QUERY_PHASE);
+	return ctx->state;
+}
+
+/* dnstap_log_response prepares dnstap CLIENT_RESPONSE message and sends it to fstrm */
+static int dnstap_log_response(kr_layer_t *ctx) {
+	dnstap_log(ctx, CLIENT_RESPONSE_PHASE);
+	return ctx->state;
+}
+
+KR_EXPORT
+int dnstap_init(struct kr_module *module) {
+	static kr_layer_api_t layer = {
+		.begin = &dnstap_log_query,
+		.finish = &dnstap_log_response,
+	};
+	/* Store module reference */
+	layer.data = module;
+	module->layer = &layer;
+
+	/* allocated memory for internal data */
+	struct dnstap_data *data = calloc(1, sizeof(*data));
+	if (!data) {
+		return kr_error(ENOMEM);
+	}
+
+	/* save pointer to internal struct in module for future reference */
+	module->data = data;
+	return kr_ok();
+}
+
+/** Clear, i.e. get to state as after the first dnstap_init(). */
+static void dnstap_clear(struct kr_module *module) {
+	struct dnstap_data *data = module->data;
+	if (data) {
+		free(data->identity);
+		free(data->version);
+
+		fstrm_iothr_destroy(&data->iothread);
+		DEBUG_MSG("fstrm iothread destroyed\n");
+	}
+}
+
+KR_EXPORT
+int dnstap_deinit(struct kr_module *module) {
+	dnstap_clear(module);
+	free(module->data);
+	return kr_ok();
+}
+
+/* dnstap_unix_writer returns a unix fstream writer
+ * https://gitlab.nic.cz/knot/knot-dns/blob/master/src/knot/modules/dnstap.c#L159
+ */
+static struct fstrm_writer* dnstap_unix_writer(const char *path) {
+
+	auto_destroy_uopts struct fstrm_unix_writer_options *opt = fstrm_unix_writer_options_init();
+	if (!opt) {
+		return NULL;
+	}
+	fstrm_unix_writer_options_set_socket_path(opt, path);
+
+	auto_destroy_wopts struct fstrm_writer_options *wopt = fstrm_writer_options_init();
+	if (!wopt) {
+		fstrm_unix_writer_options_destroy(&opt);
+		return NULL;
+	}
+	fstrm_writer_options_add_content_type(wopt, DNSTAP_CONTENT_TYPE,
+			strlen(DNSTAP_CONTENT_TYPE));
+
+	struct fstrm_writer *writer = fstrm_unix_writer_init(opt, wopt);
+	fstrm_unix_writer_options_destroy(&opt);
+	fstrm_writer_options_destroy(&wopt);
+	if (!writer) {
+		return NULL;
+	}
+
+	fstrm_res res = fstrm_writer_open(writer);
+	if (res != fstrm_res_success) {
+		DEBUG_MSG("fstrm_writer_open returned %d\n", res);
+		fstrm_writer_destroy(&writer);
+		return NULL;
+	}
+
+	return writer;
+}
+
+/* find_string
+ * create a new string from json
+ * *var is set to pointer of new string
+ * node must of type JSON_STRING
+ * new string can be at most len bytes
+ */
+static int find_string(const JsonNode *node, char **val, size_t len) {
+	if (!node || !node->key)
+		return kr_error(EINVAL);
+	if (kr_fails_assert(node->tag == JSON_STRING))
+		return kr_error(EINVAL);
+	*val = strndup(node->string_, len);
+	if (kr_fails_assert(*val != NULL))
+		return kr_error(errno);
+	return kr_ok();
+}
+
+/* find_bool returns bool from json */
+static bool find_bool(const JsonNode *node) {
+	if (!node || !node->key)
+		return false;
+	if (kr_fails_assert(node->tag == JSON_BOOL))
+		return false;
+	return node->bool_;
+}
+
+/* parse config */
+KR_EXPORT
+int dnstap_config(struct kr_module *module, const char *conf) {
+	dnstap_clear(module);
+	if (!conf) return kr_ok(); /* loaded module without configuring */
+	struct dnstap_data *data = module->data;
+	auto_free char *sock_path = NULL;
+
+	/* Empty conf passed, set default */
+	if (strlen(conf) < 1) {
+		sock_path = strdup(DEFAULT_SOCK_PATH);
+	} else {
+
+		JsonNode *root_node = json_decode(conf);
+		if (!root_node) {
+			ERROR_MSG("error parsing json\n");
+			return kr_error(EINVAL);
+		}
+
+		JsonNode *node;
+		/* dnstapPath key */
+		node = json_find_member(root_node, CFG_SOCK_PATH);
+		if (!node || find_string(node, &sock_path, PATH_MAX) != kr_ok()) {
+			sock_path = strdup(DEFAULT_SOCK_PATH);
+		}
+
+		/* identity string key */
+		node = json_find_member(root_node, CFG_IDENTITY_STRING);
+		if (!node || find_string(node, &data->identity, KR_EDNS_PAYLOAD) != kr_ok()) {
+			data->identity = NULL;
+			data->identity_len = 0;
+		} else {
+			data->identity_len = strlen(data->identity);
+		}
+
+		/* version string key */
+		node = json_find_member(root_node, CFG_VERSION_STRING);
+		if (!node || find_string(node, &data->version, KR_EDNS_PAYLOAD) != kr_ok()) {
+			data->version = strdup("Knot Resolver " PACKAGE_VERSION);
+			if (data->version) {
+				data->version_len = strlen(data->version);
+			}
+		} else {
+			data->version_len = strlen(data->version);
+		}
+
+		node = json_find_member(root_node, CFG_LOG_CLIENT_PKT);
+		if (node) {
+			JsonNode *subnode;
+			/* logRespPkt key */
+			subnode = json_find_member(node, CFG_LOG_RESP_PKT);
+			if (subnode) {
+				data->log_resp_pkt = find_bool(subnode);
+			} else {
+				data->log_resp_pkt = false;
+			}
+
+			/* logQrPkt key */
+			subnode = json_find_member(node, CFG_LOG_QR_PKT);
+			if (subnode) {
+				data->log_qr_pkt = find_bool(subnode);
+			} else {
+				data->log_qr_pkt = false;
+			}
+
+			subnode = json_find_member(node, CFG_LOG_TCP_RTT);
+			if (subnode) {
+				data->log_tcp_rtt = find_bool(subnode);
+			} else {
+				data->log_tcp_rtt = false;
+			}
+		} else {
+			data->log_qr_pkt = false;
+			data->log_resp_pkt = false;
+			data->log_tcp_rtt = false;
+		}
+
+		/* clean up json, we don't need it no more */
+		json_delete(root_node);
+	}
+
+	DEBUG_MSG("opening sock file %s\n",sock_path);
+	struct fstrm_writer *writer = dnstap_unix_writer(sock_path);
+	if (!writer) {
+		ERROR_MSG("failed to open socket %s\n"
+			"Please ensure that it exists beforehand and has appropriate access permissions.\n",
+			sock_path);
+		return kr_error(EINVAL);
+	}
+
+	struct fstrm_iothr_options *opt = fstrm_iothr_options_init();
+	if (!opt) {
+		ERROR_MSG("can't init fstrm options\n");
+		fstrm_writer_destroy(&writer);
+		return kr_error(EINVAL);
+	}
+
+	/* Create the I/O thread. */
+	data->iothread = fstrm_iothr_init(opt, &writer);
+	fstrm_iothr_options_destroy(&opt);
+	if (!data->iothread) {
+		ERROR_MSG("can't init fstrm_iothr\n");
+		fstrm_writer_destroy(&writer);
+		return kr_error(ENOMEM);
+	}
+
+	/* Get fstrm thread handle
+	 * We only have one input queue, hence idx=0
+	 */
+	data->ioq = fstrm_iothr_get_input_queue_idx(data->iothread, 0);
+	if (!data->ioq) {
+		fstrm_iothr_destroy(&data->iothread);
+		ERROR_MSG("can't get fstrm queue\n");
+		return kr_error(EBUSY);
+	}
+
+	return kr_ok();
+}
+
+KR_MODULE_EXPORT(dnstap)
+