sd-dns: initial commit

Origin: <http://0pointer.de/lennart/projects/libasyncns/>

[tomegun: renamed some more files asyncns -> sd-dns and moved to libsystemd-bus as
requested by Lennart]

.gitignore

@@ -134,6 +134,7 @@
 /test-device-nodes
 /test-dhcp-client
 /test-dhcp-option
+/test-dns
 /test-ellipsize
 /test-engine
 /test-env-replace

Makefile.am

@@ -665,6 +665,35 @@ test_rtnl_LDADD = \
 tests += \
 	test-rtnl
 
+# ------------------------------------------------------------------------------
+noinst_LTLIBRARIES += \
+	libsystemd-dns.la
+
+libsystemd_dns_la_SOURCES = \
+	src/systemd/sd-dns.h \
+	src/libsystemd-bus/sd-dns.c \
+	src/libsystemd-bus/dns-util.h
+
+libsystemd_dns_la_LIBADD = \
+	libsystemd-shared.la
+
+libsystemd_dns_la_CFLAGS = \
+	-pthread
+
+test_dns_SOURCES = \
+	src/libsystemd-bus/test-dns.c \
+	src/systemd/sd-dns.h
+
+test_dns_LDADD = \
+	libsystemd-dns.la
+
+test_dns_LDFLAGS = \
+	-lresolv \
+	-pthread
+
+tests += \
+	 test-dns
+
 # ------------------------------------------------------------------------------
 noinst_LTLIBRARIES += \
 	libsystemd-shared.la

src/libsystemd-bus/dns-util.h

@@ -0,0 +1,8 @@
+#pragma once
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(asyncns_t*, asyncns_free);
+DEFINE_TRIVIAL_CLEANUP_FUNC(unsigned char *, asyncns_freeanswer);
+DEFINE_TRIVIAL_CLEANUP_FUNC(struct addrinfo*, asyncns_freeaddrinfo);
+#define _cleanup_asyncns_free_ _cleanup_(asyncns_freep)
+#define _cleanup_asyncns_answer_free_ _cleanup_(asyncns_freeanswerp)
+#define _cleanup_asyncns_addrinfo_free_ _cleanup_(asyncns_freeaddrinfop)

src/libsystemd-bus/test-dns.c

@@ -0,0 +1,164 @@
+/***
+  This file is part of libasyncns.
+
+  Copyright 2005-2008 Lennart Poettering
+
+  libasyncns is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Lesser General Public License as
+  published by the Free Software Foundation, either version 2.1 of the
+  License, or (at your option) any later version.
+
+  libasyncns is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with libasyncns. If not, see
+  <http://www.gnu.org/licenses/>.
+ ***/
+
+#if HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <netinet/in.h>
+#include <arpa/nameser.h>
+#include <resolv.h>
+#include <assert.h>
+#include <signal.h>
+#include <errno.h>
+
+#include "sd-dns.h"
+#include "dns-util.h"
+#include "macro.h"
+
+int main(int argc, char *argv[]) {
+        int r = 1, ret;
+        _cleanup_asyncns_free_ asyncns_t *asyncns = NULL;
+        _cleanup_asyncns_addrinfo_free_ struct addrinfo *ai = NULL;
+        _cleanup_asyncns_answer_free_ unsigned char *srv = NULL;
+        asyncns_query_t *q1, *q2, *q3;
+        struct addrinfo hints = {};
+        struct sockaddr_in sa = {};
+        char host[NI_MAXHOST] = "", serv[NI_MAXSERV] = "";
+
+        signal(SIGCHLD, SIG_IGN);
+
+        asyncns = asyncns_new(2);
+        if (!asyncns)
+                log_oom();
+
+        /* Make a name -> address query */
+        hints.ai_family = PF_UNSPEC;
+        hints.ai_socktype = SOCK_STREAM;
+
+        q1 = asyncns_getaddrinfo(asyncns, argc >= 2 ? argv[1] : "www.heise.de", NULL, &hints);
+
+        if (!q1)
+                fprintf(stderr, "asyncns_getaddrinfo(): %s\n", strerror(errno));
+
+        /* Make an address -> name query */
+        sa.sin_family = AF_INET;
+        sa.sin_addr.s_addr = inet_addr(argc >= 3 ? argv[2] : "193.99.144.71");
+        sa.sin_port = htons(80);
+
+        q2 = asyncns_getnameinfo(asyncns, (struct sockaddr*) &sa, sizeof(sa), 0, 1, 1);
+
+        if (!q2)
+                fprintf(stderr, "asyncns_getnameinfo(): %s\n", strerror(errno));
+
+        /* Make a res_query() call */
+        q3 = asyncns_res_query(asyncns, "_xmpp-client._tcp.gmail.com", C_IN, T_SRV);
+
+        if (!q3)
+                fprintf(stderr, "asyncns_res_query(): %s\n", strerror(errno));
+
+        /* Wait until the three queries are completed */
+        while (!asyncns_isdone(asyncns, q1)
+                        || !asyncns_isdone(asyncns, q2)
+                        || !asyncns_isdone(asyncns, q3)) {
+                if (asyncns_wait(asyncns, 1) < 0) {
+                        fprintf(stderr, "asyncns_wait(): %s\n", strerror(errno));
+                }
+        }
+
+        /* Interpret the result of the name -> addr query */
+        if ((ret = asyncns_getaddrinfo_done(asyncns, q1, &ai)))
+                fprintf(stderr, "error: %s %i\n", gai_strerror(ret), ret);
+        else {
+                struct addrinfo *i;
+
+                for (i = ai; i; i = i->ai_next) {
+                        char t[256];
+                        const char *p = NULL;
+
+                        if (i->ai_family == PF_INET)
+                                p = inet_ntop(AF_INET, &((struct sockaddr_in*) i->ai_addr)->sin_addr, t, sizeof(t));
+                        else if (i->ai_family == PF_INET6)
+                                p = inet_ntop(AF_INET6, &((struct sockaddr_in6*) i->ai_addr)->sin6_addr, t, sizeof(t));
+
+                        printf("%s\n", p);
+                }
+        }
+
+        /* Interpret the result of the addr -> name query */
+        if ((ret = asyncns_getnameinfo_done(asyncns, q2, host, sizeof(host), serv, sizeof(serv))))
+                fprintf(stderr, "error: %s %i\n", gai_strerror(ret), ret);
+        else
+                printf("%s -- %s\n", host, serv);
+
+        /* Interpret the result of the SRV lookup */
+        if ((ret = asyncns_res_done(asyncns, q3, &srv)) < 0) {
+                fprintf(stderr, "error: %s %i\n", strerror(errno), ret);
+        } else if (ret == 0) {
+                fprintf(stderr, "No reply for SRV lookup\n");
+        } else {
+                int qdcount;
+                int ancount;
+                int len;
+                const unsigned char *pos = srv + sizeof(HEADER);
+                unsigned char *end = srv + ret;
+                HEADER *head = (HEADER *)srv;
+                char name[256];
+
+                qdcount = ntohs(head->qdcount);
+                ancount = ntohs(head->ancount);
+
+                printf("%d answers for srv lookup:\n", ancount);
+
+                /* Ignore the questions */
+                while (qdcount-- > 0 && (len = dn_expand(srv, end, pos, name, 255)) >= 0) {
+                        assert(len >= 0);
+                        pos += len + QFIXEDSZ;
+                }
+
+                /* Parse the answers */
+                while (ancount-- > 0 && (len = dn_expand(srv, end, pos, name, 255)) >= 0) {
+                        /* Ignore the initial string */
+                        uint16_t pref, weight, port;
+                        assert(len >= 0);
+                        pos += len;
+                        /* Ignore type, ttl, class and dlen */
+                        pos += 10;
+
+                        GETSHORT(pref, pos);
+                        GETSHORT(weight, pos);
+                        GETSHORT(port, pos);
+                        len = dn_expand(srv, end, pos, name, 255);
+                        printf("\tpreference: %2d weight: %2d port: %d host: %s\n",
+                                        pref, weight, port, name);
+
+                        pos += len;
+                }
+        }
+
+        r = 0;
+
+        return r;
+}

src/systemd/sd-dns.h

@@ -0,0 +1,156 @@
+#ifndef fooasyncnshfoo
+#define fooasyncnshfoo
+
+/***
+  This file is part of libasyncns.
+
+  Copyright 2005-2008 Lennart Poettering
+
+  libasyncns is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Lesser General Public License as
+  published by the Free Software Foundation, either version 2.1 of the
+  License, or (at your option) any later version.
+
+  libasyncns is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with libasyncns. If not, see
+  <http://www.gnu.org/licenses/>.
+***/
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include "macro.h"
+#include "util.h"
+/** \mainpage
+ *
+ * \section moo Method of operation
+ *
+ * To use libasyncns allocate an asyncns_t object with
+ * asyncns_new(). This will spawn a number of worker threads (or processes, depending on what is available) which
+ * are subsequently used to process the queries the controlling
+ * program issues via asyncns_getaddrinfo() and
+ * asyncns_getnameinfo(). Use asyncns_free() to shut down the worker
+ * threads/processes.
+ *
+ * Since libasyncns may fork off new processes you have to make sure that
+ * your program is not irritated by spurious SIGCHLD signals.
+ */
+
+/** \example asyncns-test.c
+ * An example program */
+
+/** An opaque libasyncns session structure */
+typedef struct asyncns asyncns_t;
+
+/** An opaque libasyncns query structure */
+typedef struct asyncns_query asyncns_query_t;
+
+/** Allocate a new libasyncns session with n_proc worker processes/threads */
+asyncns_t* asyncns_new(unsigned n_proc);
+
+/** Free a libasyncns session. This destroys all attached
+ * asyncns_query_t objects automatically */
+void asyncns_free(asyncns_t *asyncns);
+
+/** Return the UNIX file descriptor to select() for readability
+ * on. Use this function to integrate libasyncns with your custom main
+ * loop. */
+int asyncns_fd(asyncns_t *asyncns);
+
+/** Process pending responses. After this function is called you can
+ * get the next completed query object(s) using asyncns_getnext(). If
+ * block is non-zero wait until at least one response has been
+ * processed. If block is zero, process all pending responses and
+ * return. */
+int asyncns_wait(asyncns_t *asyncns, int block);
+
+/** Issue a name to address query on the specified session. The
+ * arguments are compatible with the ones of libc's
+ * getaddrinfo(3). The function returns a new query object. When the
+ * query is completed you may retrieve the results using
+ * asyncns_getaddrinfo_done().*/
+asyncns_query_t* asyncns_getaddrinfo(asyncns_t *asyncns, const char *node, const char *service, const struct addrinfo *hints);
+
+/** Retrieve the results of a preceding asyncns_getaddrinfo()
+ * call. Returns a addrinfo structure and a return value compatible
+ * with libc's getaddrinfo(3). The query object q is destroyed by this
+ * call and may not be used any further. Make sure to free the
+ * returned addrinfo structure with asyncns_freeaddrinfo() and not
+ * libc's freeaddrinfo(3)! If the query is not completed yet EAI_AGAIN
+ * is returned.*/
+int asyncns_getaddrinfo_done(asyncns_t *asyncns, asyncns_query_t* q, struct addrinfo **ret_res);
+
+/** Issue an address to name query on the specified session. The
+ * arguments are compatible with the ones of libc's
+ * getnameinfo(3). The function returns a new query object. When the
+ * query is completed you may retrieve the results using
+ * asyncns_getnameinfo_done(). Set gethost (resp. getserv) to non-zero
+ * if you want to query the hostname (resp. the service name). */
+asyncns_query_t* asyncns_getnameinfo(asyncns_t *asyncns, const struct sockaddr *sa, socklen_t salen, int flags, int gethost, int getserv);
+
+/** Retrieve the results of a preceding asyncns_getnameinfo()
+ * call. Returns the hostname and the service name in ret_host and
+ * ret_serv. The query object q is destroyed by this call and may not
+ * be used any further. If the query is not completed yet EAI_AGAIN is
+ * returned. */
+int asyncns_getnameinfo_done(asyncns_t *asyncns, asyncns_query_t* q, char *ret_host, size_t hostlen, char *ret_serv, size_t servlen);
+
+/** Issue a resolver query on the specified session. The arguments are
+ * compatible with the ones of libc's res_query(3). The function returns a new
+ * query object. When the query is completed you may retrieve the results using
+ * asyncns_res_done().  */
+asyncns_query_t* asyncns_res_query(asyncns_t *asyncns, const char *dname, int class, int type);
+
+/** Issue an resolver query on the specified session. The arguments are
+ * compatible with the ones of libc's res_search(3). The function returns a new
+ * query object. When the query is completed you may retrieve the results using
+ * asyncns_res_done().  */
+asyncns_query_t* asyncns_res_search(asyncns_t *asyncns, const char *dname, int class, int type);
+
+/** Retrieve the results of a preceding asyncns_res_query() or
+ * asyncns_res_search call.  The query object q is destroyed by this
+ * call and may not be used any further. Returns a pointer to the
+ * answer of the res_query call. If the query is not completed yet
+ * -EAGAIN is returned, on failure -errno is returned, otherwise the
+ * length of answer is returned. Make sure to free the answer is a
+ * call to asyncns_freeanswer(). */
+int asyncns_res_done(asyncns_t *asyncns, asyncns_query_t* q, unsigned char **answer);
+
+/** Return the next completed query object. If no query has been
+ * completed yet, return NULL. Please note that you need to run
+ * asyncns_wait() before this function will return sensible data.  */
+asyncns_query_t* asyncns_getnext(asyncns_t *asyncns);
+
+/** Return the number of query objects (completed or not) attached to
+ * this session */
+int asyncns_getnqueries(asyncns_t *asyncns);
+
+/** Cancel a currently running query. q is is destroyed by this call
+ * and may not be used any futher. */
+void asyncns_cancel(asyncns_t *asyncns, asyncns_query_t* q);
+
+/** Free the addrinfo structure as returned by
+ * asyncns_getaddrinfo_done(). Make sure to use this functions instead
+ * of the libc's freeaddrinfo()! */
+void asyncns_freeaddrinfo(struct addrinfo *ai);
+
+/** Free the answer data as returned by asyncns_res_done().*/
+void asyncns_freeanswer(unsigned char *answer);
+
+/** Returns non-zero when the query operation specified by q has been completed */
+int asyncns_isdone(asyncns_t *asyncns, asyncns_query_t*q);
+
+/** Assign some opaque userdata with a query object */
+void asyncns_setuserdata(asyncns_t *asyncns, asyncns_query_t *q, void *userdata);
+
+/** Return userdata assigned to a query object. Use
+ * asyncns_setuserdata() to set this data. If no data has been set
+ * prior to this call it returns NULL. */
+void* asyncns_getuserdata(asyncns_t *asyncns, asyncns_query_t *q);
+
+#endif