loudmouth/src/asyncns.c
changeset 0 d0f3a028347a
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/loudmouth/src/asyncns.c	Tue Feb 02 01:10:06 2010 +0200
@@ -0,0 +1,1143 @@
+/* $Id: asyncns.c 27 2007-02-16 13:51:03Z lennart $ */
+
+/***
+  This file is part of libasyncns.
+  Copyright (C) 2006 Collabora Ltd.
+  
+  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 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
+  General Public License for more details.
+ 
+  You should have received a copy of the GNU Lesser General Public
+  License along with libasyncns; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+/*#undef HAVE_PTHREAD */
+
+#include <assert.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <unistd.h>
+#include <sys/select.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/wait.h>
+#include <sys/types.h>
+#include <pwd.h>
+#include <netinet/in.h>
+#include <arpa/nameser.h>
+#include <resolv.h>
+
+#ifdef HAVE_SYS_PRCTL_H
+#include <sys/prctl.h>
+#endif
+
+#if HAVE_PTHREAD
+#include <pthread.h>
+#endif
+
+#include "asyncns.h"
+
+#define MAX_WORKERS 16
+#define MAX_QUERIES 256
+#define BUFSIZE (10240)
+
+typedef enum {
+    REQUEST_ADDRINFO,
+    RESPONSE_ADDRINFO,
+    REQUEST_NAMEINFO,
+    RESPONSE_NAMEINFO,
+    REQUEST_RES_QUERY,
+    REQUEST_RES_SEARCH,
+    RESPONSE_RES,
+    REQUEST_TERMINATE
+} query_type_t;
+
+enum {
+    REQUEST_RECV_FD = 0,
+    REQUEST_SEND_FD = 1,
+    RESPONSE_RECV_FD = 2,
+    RESPONSE_SEND_FD = 3
+};
+
+struct asyncns {
+    int fds[4];
+
+#ifndef HAVE_PTHREAD    
+    pid_t workers[MAX_WORKERS];
+#else
+    pthread_t workers[MAX_WORKERS];
+#endif
+    unsigned valid_workers;
+
+    unsigned current_id, current_index;
+    asyncns_query_t* queries[MAX_QUERIES];
+
+    asyncns_query_t *done_head, *done_tail;
+
+    int n_queries;
+};
+
+struct asyncns_query {
+    asyncns_t *asyncns;
+    int done;
+    unsigned id;
+    query_type_t type;
+    asyncns_query_t *done_next, *done_prev;
+    int ret;
+    struct addrinfo *addrinfo;
+    char *serv, *host;
+    void *userdata;
+};
+
+typedef struct rheader {
+    query_type_t type;
+    unsigned id;
+    size_t length;
+} rheader_t;
+
+typedef struct addrinfo_request {
+    struct rheader header;
+    int hints_is_null;
+    int ai_flags;
+    int ai_family;
+    int ai_socktype;
+    int ai_protocol;
+    size_t node_len, service_len;
+} addrinfo_request_t;
+
+typedef struct addrinfo_response {
+    struct rheader header;
+    int ret;
+} addrinfo_response_t;
+
+typedef struct addrinfo_serialization {
+    int ai_flags;
+    int ai_family;
+    int ai_socktype;
+    int ai_protocol;
+    size_t ai_addrlen;
+    size_t canonname_len;
+} addrinfo_serialization_t;
+
+typedef struct nameinfo_request {
+    struct rheader header;
+    int flags;
+    socklen_t sockaddr_len;
+    int gethost, getserv;
+} nameinfo_request_t;
+
+typedef struct nameinfo_response {
+    struct rheader header;
+    size_t hostlen, servlen;
+    int ret;
+} nameinfo_response_t;
+
+typedef struct res_query_request {
+    struct rheader header;
+    int class;
+    int type;
+    size_t dlen;
+} res_request_t;
+
+typedef struct res_query_response {
+    struct rheader header;
+    int ret;
+} res_response_t;
+
+#ifndef HAVE_STRNDUP
+
+static char *strndup(const char *s, size_t l) {
+    size_t a;
+    char *n;
+
+    a = strlen(s);
+    if (a > l)
+        a = l;
+
+    if (!(n = malloc(a+1)))
+        return NULL;
+
+    strncpy(n, s, a);
+    n[a] = 0;
+
+    return n;
+}
+
+#endif
+
+static int fd_nonblock(int fd) {
+    int i;
+    assert(fd >= 0);
+
+    if ((i = fcntl(fd, F_GETFL, 0)) < 0)
+        return -1;
+
+    if (i & O_NONBLOCK)
+        return 0;
+
+    return fcntl(fd, F_SETFL, i | O_NONBLOCK);
+}
+
+static int fd_cloexec(int fd) {
+    int v;
+    assert(fd >= 0);
+
+    if ((v = fcntl(fd, F_GETFD, 0)) < 0)
+        return -1;
+
+    if (v & FD_CLOEXEC)
+        return 0;
+    
+    return fcntl(fd, F_SETFD, v | FD_CLOEXEC);
+}
+
+
+static void *serialize_addrinfo(void *p, const struct addrinfo *ai, size_t *length, size_t maxlength) {
+    addrinfo_serialization_t *s = p;
+    size_t cnl, l;
+    assert(p);
+    assert(ai);
+    assert(length);
+    assert(*length <= maxlength);
+
+    cnl = (ai->ai_canonname ? strlen(ai->ai_canonname)+1 : 0);
+    l = sizeof(addrinfo_serialization_t) + ai->ai_addrlen + cnl;
+
+    if (*length + l > maxlength)
+        return NULL;
+
+    s->ai_flags = ai->ai_flags;
+    s->ai_family = ai->ai_family;
+    s->ai_socktype = ai->ai_socktype;
+    s->ai_protocol = ai->ai_protocol;
+    s->ai_addrlen = ai->ai_addrlen;
+    s->canonname_len = cnl;
+
+    memcpy((uint8_t*) p + sizeof(addrinfo_serialization_t), ai->ai_addr, ai->ai_addrlen);
+
+    if (ai->ai_canonname)
+        strcpy((char*) p + sizeof(addrinfo_serialization_t) + ai->ai_addrlen, ai->ai_canonname);
+
+    *length += l;
+    return (uint8_t*) p + l;
+}
+
+static int send_addrinfo_reply(int out_fd, unsigned id, int ret, struct addrinfo *ai) {
+    uint8_t data[BUFSIZE];
+    addrinfo_response_t *resp = (addrinfo_response_t*) data;
+    assert(out_fd >= 0);
+
+    resp->header.type = RESPONSE_ADDRINFO;
+    resp->header.id = id;
+    resp->header.length = sizeof(addrinfo_response_t);
+    resp->ret = ret;
+
+    if (ret == 0 && ai) {
+        void *p = data + sizeof(addrinfo_response_t);
+
+        while (ai && p) {
+            p = serialize_addrinfo(p, ai, &resp->header.length, BUFSIZE);
+            ai = ai->ai_next;
+        }
+    }
+
+    if (ai)
+        freeaddrinfo(ai);
+
+    return send(out_fd, resp, resp->header.length, 0);
+}
+
+static int send_nameinfo_reply(int out_fd, unsigned id, int ret, const char *host, const char *serv) {
+    uint8_t data[BUFSIZE];
+    size_t hl, sl;
+    nameinfo_response_t *resp = (nameinfo_response_t*) data;
+
+    assert(out_fd >= 0);
+    
+    sl = serv ? strlen(serv)+1 : 0;
+    hl = host ? strlen(host)+1 : 0;
+
+    resp->header.type = RESPONSE_NAMEINFO;
+    resp->header.id = id;
+    resp->header.length = sizeof(nameinfo_response_t) + hl + sl;
+    resp->ret = ret;
+    resp->hostlen = hl;
+    resp->servlen = sl;
+
+    assert(sizeof(data) >= resp->header.length);
+    
+    if (host)
+        memcpy(data + sizeof(nameinfo_response_t), host, hl);
+
+    if (serv)
+        memcpy(data + sizeof(nameinfo_response_t) + hl, serv, sl);
+    
+    return send(out_fd, resp, resp->header.length, 0);
+}
+
+static int send_res_reply(int out_fd, unsigned id, const unsigned char *answer, int ret) {
+    uint8_t data[BUFSIZE];
+    res_response_t *resp = (res_response_t *) data;
+
+    assert(out_fd >= 0);
+    
+    resp->header.type = RESPONSE_RES;
+    resp->header.id = id;
+    resp->header.length = sizeof(res_response_t) + (ret < 0 ? 0 : ret);
+    resp->ret = (ret < 0) ? -errno : ret;
+
+    assert(sizeof(data) >= resp->header.length);
+    
+    if (ret > 0)
+        memcpy(data + sizeof(res_response_t), answer, ret);
+
+    return send(out_fd, resp, resp->header.length, 0);
+}
+
+static int handle_request(int out_fd, const rheader_t *req, size_t length) {
+    assert(out_fd >= 0);
+    assert(req);
+    assert(length >= sizeof(rheader_t));
+    assert(length == req->length);
+
+    switch (req->type) {
+        case REQUEST_ADDRINFO: {
+            struct addrinfo ai, *result = NULL;
+            const addrinfo_request_t *ai_req = (const addrinfo_request_t*) req;
+            const char *node, *service;
+            int ret;
+
+            assert(length >= sizeof(addrinfo_request_t));
+            assert(length == sizeof(addrinfo_request_t) + ai_req->node_len + ai_req->service_len);
+
+            memset(&ai, 0, sizeof(ai));
+            ai.ai_flags = ai_req->ai_flags;
+            ai.ai_family = ai_req->ai_family;
+            ai.ai_socktype = ai_req->ai_socktype;
+            ai.ai_protocol = ai_req->ai_protocol;
+
+            node = ai_req->node_len ? (const char*) req + sizeof(addrinfo_request_t) : NULL;
+            service = ai_req->service_len ? (const char*) req + sizeof(addrinfo_request_t) + ai_req->node_len : NULL;
+
+            /*printf("[getaddrinfo for '%s']\n", node);*/
+            ret = getaddrinfo(node, service,
+                              ai_req->hints_is_null ? NULL : &ai,
+                              &result);
+            /*printf("[return value: %d: '%s']\n", ret, gai_strerror(ret));*/
+
+            /* send_addrinfo_reply() frees result */
+            return send_addrinfo_reply(out_fd, req->id, ret, result);
+        }
+
+        case REQUEST_NAMEINFO: {
+            int ret;
+            const nameinfo_request_t *ni_req = (const nameinfo_request_t*) req;
+            char hostbuf[NI_MAXHOST], servbuf[NI_MAXSERV];
+            const struct sockaddr *sa;
+            
+            assert(length >= sizeof(nameinfo_request_t));
+            assert(length == sizeof(nameinfo_request_t) + ni_req->sockaddr_len);
+
+            sa = (const struct sockaddr*) ((const char*) req + sizeof(nameinfo_request_t));
+            
+            ret = getnameinfo(sa, ni_req->sockaddr_len,
+                              ni_req->gethost ? hostbuf : NULL, ni_req->gethost ? sizeof(hostbuf) : 0,
+                              ni_req->getserv ? servbuf : NULL, ni_req->getserv ? sizeof(servbuf) : 0,
+                              ni_req->flags);
+
+            return send_nameinfo_reply(out_fd, req->id, ret,
+                                       ret == 0 && ni_req->gethost ? hostbuf : NULL,
+                                       ret == 0 && ni_req->getserv ? servbuf : NULL);
+        }
+
+        case REQUEST_RES_QUERY: 
+        case REQUEST_RES_SEARCH: {
+            int ret;
+            unsigned char answer[BUFSIZE];
+            const res_request_t *res_req = (const res_request_t *)req;
+            const char *dname;
+
+            assert(length >= sizeof(res_request_t));
+            assert(length == sizeof(res_request_t) + res_req->dlen + 1);
+
+            dname = (const char *) req + sizeof(res_request_t);
+
+            if (req->type == REQUEST_RES_QUERY) { 
+                /*printf("[res query for '%s']\n", dname);*/
+                ret = res_query(dname, res_req->class, res_req->type, 
+                                answer, BUFSIZE);
+                /*printf("[return value: %d]\n", ret);*/
+            } else {
+                ret = res_search(dname, res_req->class, res_req->type, 
+                                 answer, BUFSIZE);
+            }
+            return send_res_reply(out_fd, req->id, answer, ret);
+        }
+
+        case REQUEST_TERMINATE: {
+            /* Quit */
+            return -1;
+        }
+
+        default:
+            ;
+    }
+
+    return 0;
+}
+
+#ifndef HAVE_PTHREAD
+
+static int process_worker(int in_fd, int out_fd) {
+    int have_death_sig = 0;
+    assert(in_fd > 2);
+    assert(out_fd > 2);
+    
+    close(0);
+    close(1);
+    close(2);
+
+    open("/dev/null", O_RDONLY);
+    open("/dev/null", O_WRONLY);
+    open("/dev/null", O_WRONLY);
+
+    chdir("/");
+
+    if (geteuid() == 0) {
+        struct passwd *pw;
+
+        if ((pw = getpwnam("nobody"))) {
+#ifdef HAVE_SETRESUID            
+            setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid);
+#elif HAVE_SETREUID
+            setreuid(pw->pw_uid, pw->pw_uid);
+#else
+            setuid(pw->pw_uid);
+            seteuid(pw->pw_uid);
+#endif
+        }
+    }
+
+    signal(SIGTERM, SIG_DFL);
+
+    signal(SIGINT, SIG_IGN);
+    signal(SIGHUP, SIG_IGN);
+    signal(SIGPIPE, SIG_IGN);
+    signal(SIGUSR1, SIG_IGN);
+    signal(SIGUSR2, SIG_IGN);
+
+#ifdef PR_SET_PDEATHSIG
+    if (prctl(PR_SET_PDEATHSIG, SIGTERM) >= 0)
+        have_death_sig = 1;
+#endif
+
+    if (!have_death_sig)
+        fd_nonblock(in_fd);
+    
+    while (getppid() > 1) { /* if the parent PID is 1 our parent process died. */
+        char buf[BUFSIZE];
+        ssize_t length;
+
+        if (!have_death_sig) {
+            fd_set fds;
+            struct timeval tv = { 0, 500000 } ;
+            
+            FD_ZERO(&fds);
+            FD_SET(in_fd, &fds);
+            
+            if (select(in_fd+1, &fds, NULL, NULL, &tv) < 0)
+                break;
+            
+            if (getppid() == 1)
+                break;
+        }
+        
+        if ((length = recv(in_fd, buf, sizeof(buf), 0)) <= 0) {
+
+            if (length < 0 && errno == EAGAIN)
+                continue;
+
+            break;
+        }
+
+        if (handle_request(out_fd, (rheader_t*) buf, (size_t) length) < 0)
+            break;
+    }
+
+    close(in_fd);
+    close(out_fd);
+    
+    return 0;
+}
+
+#else
+
+static void* thread_worker(void *p) {
+    sigset_t fullset;
+    int *fds = p;
+    pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, NULL);
+
+    /* No signals in this thread please */
+    sigfillset(&fullset);
+    pthread_sigmask(SIG_BLOCK, &fullset, NULL);
+    
+    for (;;) {
+        char buf[BUFSIZE];
+        ssize_t length;
+
+        if ((length = recv(fds[REQUEST_RECV_FD], buf, sizeof(buf), 0)) <= 0)
+            break;
+
+        if (handle_request(fds[RESPONSE_SEND_FD], (rheader_t*) buf, (size_t) length) < 0)
+            break;
+        
+    }
+
+    return NULL;
+}
+
+#endif
+
+asyncns_t* asyncns_new(unsigned n_proc) {
+    asyncns_t *asyncns = NULL;
+    int i;
+    unsigned p;
+    assert(n_proc >= 1);
+
+    if (n_proc > MAX_WORKERS)
+        n_proc = MAX_WORKERS;
+
+    if (!(asyncns = malloc(sizeof(asyncns_t))))
+        goto fail;
+
+    asyncns->valid_workers = 0;
+
+    for (i = 0; i < 4; i++) 
+        asyncns->fds[i] = -1;
+        
+    for (p = 0; p < MAX_QUERIES; p++)
+        asyncns->queries[p] = NULL;
+    
+    if (socketpair(PF_UNIX, SOCK_DGRAM, 0, asyncns->fds) < 0 ||
+        socketpair(PF_UNIX, SOCK_DGRAM, 0, asyncns->fds+2) < 0)
+        goto fail;
+    
+    for (i = 0; i < 4; i++) 
+        fd_cloexec(asyncns->fds[i]);
+
+    for (asyncns->valid_workers = 0; asyncns->valid_workers < n_proc; asyncns->valid_workers++) {
+
+#ifndef HAVE_PTHREAD
+        if ((asyncns->workers[asyncns->valid_workers] = fork()) < 0)
+            goto fail;
+        else if (asyncns->workers[asyncns->valid_workers] == 0) {
+            close(asyncns->fds[REQUEST_SEND_FD]);
+            close(asyncns->fds[RESPONSE_RECV_FD]);
+            _exit(process_worker(asyncns->fds[REQUEST_RECV_FD], asyncns->fds[RESPONSE_SEND_FD]));
+        }
+#else
+        if (pthread_create(&asyncns->workers[asyncns->valid_workers], NULL, thread_worker, asyncns->fds) != 0)
+            goto fail;
+#endif
+    }
+
+#ifndef HAVE_PTHREAD
+    close(asyncns->fds[REQUEST_RECV_FD]);
+    close(asyncns->fds[RESPONSE_SEND_FD]);
+    asyncns->fds[REQUEST_RECV_FD] = asyncns->fds[RESPONSE_SEND_FD] = -1;
+#endif    
+    
+    asyncns->current_index = asyncns->current_id = 0;
+    asyncns->done_head = asyncns->done_tail = NULL;
+    asyncns->n_queries = 0;
+
+    fd_nonblock(asyncns->fds[RESPONSE_RECV_FD]);
+
+    return asyncns;
+
+fail:
+    if (asyncns) 
+        asyncns_free(asyncns);
+
+    return NULL;
+}
+
+void asyncns_free(asyncns_t *asyncns) {
+    unsigned p;
+    int i;
+    rheader_t req;
+    assert(asyncns);
+
+    req.type = REQUEST_TERMINATE;
+    req.length = sizeof(req);
+    req.id = 0;
+    
+    /* Send one termiantion packet for each worker */
+    for (p = 0; p < asyncns->valid_workers; p++)
+        send(asyncns->fds[REQUEST_SEND_FD], &req, req.length, 0);
+
+    /* No terminate them forcibly*/
+    for (p = 0; p < asyncns->valid_workers; p++) {
+#ifndef HAVE_PTHREAD
+        kill(asyncns->workers[p], SIGTERM);
+        waitpid(asyncns->workers[p], NULL, 0);
+#else
+        pthread_cancel(asyncns->workers[p]);
+        pthread_join(asyncns->workers[p], NULL);
+#endif        
+    }
+
+    /* Due to Solaris' broken thread cancelation we first send an
+     * termination request and then cancel th thread. */
+
+    
+    for (i = 0; i < 4; i++)
+        if (asyncns->fds[i] >= 0)
+            close(asyncns->fds[i]);
+    
+    for (p = 0; p < MAX_QUERIES; p++)
+        if (asyncns->queries[p])
+            asyncns_cancel(asyncns, asyncns->queries[p]);
+    
+    free(asyncns);
+}
+
+int asyncns_fd(asyncns_t *asyncns) {
+    assert(asyncns);
+
+    return asyncns->fds[RESPONSE_RECV_FD];
+}
+
+static asyncns_query_t *lookup_query(asyncns_t *asyncns, unsigned id) {
+    asyncns_query_t *q;
+    assert(asyncns);
+
+    if ((q = asyncns->queries[id % MAX_QUERIES]))
+        if (q->id == id)
+            return q;
+
+    return NULL;
+}
+
+static void complete_query(asyncns_t *asyncns, asyncns_query_t *q) {
+    assert(asyncns);
+    assert(q);
+    assert(!q->done);
+
+    q->done = 1;
+    
+    if ((q->done_prev = asyncns->done_tail))
+        asyncns->done_tail->done_next = q;
+    else
+        asyncns->done_head = q;
+
+    asyncns->done_tail = q;
+    q->done_next = NULL;
+}
+
+static void *unserialize_addrinfo(void *p, struct addrinfo **ret_ai, size_t *length) {
+    addrinfo_serialization_t *s = p;
+    size_t l;
+    struct addrinfo *ai;
+    assert(p);
+    assert(ret_ai);
+    assert(length);
+
+    if (*length < sizeof(addrinfo_serialization_t))
+        return NULL;
+
+    l = sizeof(addrinfo_serialization_t) + s->ai_addrlen + s->canonname_len;
+    if (*length < l)
+        return NULL;
+
+    if (!(ai = malloc(sizeof(struct addrinfo))))
+        goto fail;
+    
+    ai->ai_addr = NULL;
+    ai->ai_canonname = NULL;
+    ai->ai_next = NULL;
+
+    if (s->ai_addrlen && !(ai->ai_addr = malloc(s->ai_addrlen)))
+        goto fail;
+    
+    if (s->canonname_len && !(ai->ai_canonname = malloc(s->canonname_len)))
+        goto fail;
+
+    ai->ai_flags = s->ai_flags;
+    ai->ai_family = s->ai_family;
+    ai->ai_socktype = s->ai_socktype;
+    ai->ai_protocol = s->ai_protocol;
+    ai->ai_addrlen = s->ai_addrlen;
+
+    if (ai->ai_addr)
+        memcpy(ai->ai_addr, (uint8_t*) p + sizeof(addrinfo_serialization_t), s->ai_addrlen);
+
+    if (ai->ai_canonname)
+        memcpy(ai->ai_canonname, (uint8_t*) p + sizeof(addrinfo_serialization_t) + s->ai_addrlen, s->canonname_len);
+
+    *length -= l;
+    *ret_ai = ai;
+    
+    return (uint8_t*) p + l;
+
+
+fail:
+    if (ai)
+        asyncns_freeaddrinfo(ai);
+
+    return NULL;
+}
+
+static int handle_response(asyncns_t *asyncns, rheader_t *resp, size_t length) {
+    asyncns_query_t *q;
+    assert(asyncns);
+    assert(resp);
+    assert(length >= sizeof(rheader_t));
+    assert(length == resp->length);
+
+    if (!(q = lookup_query(asyncns, resp->id)))
+        return 0;
+    
+    switch (resp->type) {
+        case RESPONSE_ADDRINFO: {
+            const addrinfo_response_t *ai_resp = (addrinfo_response_t*) resp;
+            void *p;
+            size_t l;
+            struct addrinfo *prev = NULL;
+
+            assert(length >= sizeof(addrinfo_response_t));
+            assert(q->type == REQUEST_ADDRINFO);
+
+            q->ret = ai_resp->ret;
+            l = length - sizeof(addrinfo_response_t);
+            p = (uint8_t*) resp + sizeof(addrinfo_response_t);
+
+            while (l > 0 && p) {
+                struct addrinfo *ai = NULL;
+                p = unserialize_addrinfo(p, &ai, &l);
+
+                if (!ai)
+                    break;
+
+                if (prev)
+                    prev->ai_next = ai;
+                else
+                    q->addrinfo = ai;
+
+                prev = ai;
+            }
+
+            complete_query(asyncns, q);
+            break;
+        }
+
+        case RESPONSE_NAMEINFO: {
+            const nameinfo_response_t *ni_resp = (nameinfo_response_t*) resp;
+
+            assert(length >= sizeof(nameinfo_response_t));
+            assert(q->type == REQUEST_NAMEINFO);
+
+            q->ret = ni_resp->ret;
+
+            if (ni_resp->hostlen)
+                q->host = strndup((const char*) ni_resp + sizeof(nameinfo_response_t), ni_resp->hostlen-1);
+
+            if (ni_resp->servlen)
+                q->serv = strndup((const char*) ni_resp + sizeof(nameinfo_response_t) + ni_resp->hostlen, ni_resp->servlen-1);
+                    
+
+            complete_query(asyncns, q);
+            break;
+        }
+
+        case RESPONSE_RES: {
+            const res_response_t *res_resp = (res_response_t *)resp;
+
+            assert(length >= sizeof(res_response_t));
+            assert(q->type == REQUEST_RES_QUERY || q->type == REQUEST_RES_SEARCH);
+
+            q->ret = res_resp->ret;
+
+            if (res_resp->ret >= 0)  {
+                q->serv = malloc(res_resp->ret);
+                memcpy(q->serv, (char *)resp + sizeof(res_response_t), res_resp->ret);
+            }
+
+            complete_query(asyncns, q);
+            break;
+        }
+            
+        default:
+            ;
+    }
+    
+    return 0;
+}
+
+int asyncns_wait(asyncns_t *asyncns, int block) {
+    int handled = 0;
+    assert(asyncns);
+
+    for (;;) {
+        char buf[BUFSIZE];
+        ssize_t l;
+
+        if (((l = recv(asyncns->fds[RESPONSE_RECV_FD], buf, sizeof(buf), 0)) < 0)) {
+            fd_set fds;
+
+            if (errno != EAGAIN)
+                return -1;
+
+            if (!block || handled)
+                return 0;
+                
+            FD_ZERO(&fds);
+            FD_SET(asyncns->fds[RESPONSE_RECV_FD], &fds);
+
+            if (select(asyncns->fds[RESPONSE_RECV_FD]+1, &fds, NULL, NULL, NULL) < 0)
+                return -1;
+                
+            continue;
+        }
+
+
+        if (handle_response(asyncns, (rheader_t*) buf, (size_t) l) < 0)
+            return -1;
+
+        handled = 1;
+    }
+}
+
+static asyncns_query_t *alloc_query(asyncns_t *asyncns) {
+    asyncns_query_t *q;
+    assert(asyncns);
+
+    if (asyncns->n_queries >= MAX_QUERIES)
+        return NULL;
+
+    while (asyncns->queries[asyncns->current_index]) {
+
+        asyncns->current_index++;
+        asyncns->current_id++;
+
+        while (asyncns->current_index >= MAX_QUERIES)
+            asyncns->current_index -= MAX_QUERIES;
+    }
+        
+    if (!(q = asyncns->queries[asyncns->current_index] = malloc(sizeof(asyncns_query_t))))
+        return NULL;
+
+    asyncns->n_queries++;
+
+    q->asyncns = asyncns;
+    q->done = 0;
+    q->id = asyncns->current_id;
+    q->done_next = q->done_prev = NULL;
+    q->ret = 0;
+    q->addrinfo = NULL;
+    q->userdata = NULL;
+    q->host = q->serv = NULL;
+
+    return q;
+}
+
+asyncns_query_t* asyncns_getaddrinfo(asyncns_t *asyncns, const char *node, const char *service, const struct addrinfo *hints) {
+    uint8_t data[BUFSIZE];
+    addrinfo_request_t *req = (addrinfo_request_t*) data;
+    asyncns_query_t *q;
+    assert(asyncns);
+    assert(node || service);
+
+    if (!(q = alloc_query(asyncns)))
+        return NULL;
+
+    memset(req, 0, sizeof(addrinfo_request_t));
+    
+    req->node_len = node ? strlen(node)+1 : 0;
+    req->service_len = service ? strlen(service)+1 : 0;
+    
+    req->header.id = q->id;
+    req->header.type = q->type = REQUEST_ADDRINFO;
+    req->header.length = sizeof(addrinfo_request_t) + req->node_len + req->service_len;
+
+    if (req->header.length > BUFSIZE)
+        goto fail;
+
+    if (!(req->hints_is_null = !hints)) {
+        req->ai_flags = hints->ai_flags; 
+        req->ai_family = hints->ai_family;
+        req->ai_socktype = hints->ai_socktype;
+        req->ai_protocol = hints->ai_protocol;
+    }
+
+    if (node)
+        strcpy((char*) req + sizeof(addrinfo_request_t), node);
+
+    if (service)
+        strcpy((char*) req + sizeof(addrinfo_request_t) + req->node_len, service);
+
+    if (send(asyncns->fds[REQUEST_SEND_FD], req, req->header.length, 0) < 0)
+        goto fail;
+    
+    return q;
+
+fail:
+    if (q)
+        asyncns_cancel(asyncns, q);
+
+    return NULL;
+}
+
+int asyncns_getaddrinfo_done(asyncns_t *asyncns, asyncns_query_t* q, struct addrinfo **ret_res) {
+    int ret;
+    assert(asyncns);
+    assert(q);
+    assert(q->asyncns == asyncns);
+    assert(q->type == REQUEST_ADDRINFO);
+
+    if (!q->done)
+        return EAI_AGAIN;
+
+    *ret_res = q->addrinfo;
+    q->addrinfo = NULL;
+    ret = q->ret;
+    asyncns_cancel(asyncns, q);
+
+    return ret;
+}
+
+asyncns_query_t* asyncns_getnameinfo(asyncns_t *asyncns, const struct sockaddr *sa, socklen_t salen, int flags, int gethost, int getserv) {
+    uint8_t data[BUFSIZE];
+    nameinfo_request_t *req = (nameinfo_request_t*) data;
+    asyncns_query_t *q;
+
+    assert(asyncns);
+    assert(sa);
+    assert(salen > 0);
+
+    if (!(q = alloc_query(asyncns)))
+        return NULL;
+
+    memset(req, 0, sizeof(nameinfo_request_t));
+    
+    req->header.id = q->id;
+    req->header.type = q->type = REQUEST_NAMEINFO;
+    req->header.length = sizeof(nameinfo_request_t) + salen;
+
+    if (req->header.length > BUFSIZE)
+        goto fail;
+
+    req->flags = flags;
+    req->sockaddr_len = salen;
+    req->gethost = gethost;
+    req->getserv = getserv;
+
+    memcpy((uint8_t*) req + sizeof(nameinfo_request_t), sa, salen);
+
+    if (send(asyncns->fds[REQUEST_SEND_FD], req, req->header.length, 0) < 0)
+        goto fail;
+    
+    return q;
+
+fail:
+    if (q)
+        asyncns_cancel(asyncns, q);
+
+    return NULL;
+}
+
+int asyncns_getnameinfo_done(asyncns_t *asyncns, asyncns_query_t* q, char *ret_host, size_t hostlen, char *ret_serv, size_t servlen) {
+    int ret;
+    assert(asyncns);
+    assert(q);
+    assert(q->asyncns == asyncns);
+    assert(q->type == REQUEST_NAMEINFO);
+    assert(!ret_host || hostlen);
+    assert(!ret_serv || servlen);
+
+    if (!q->done)
+        return EAI_AGAIN;
+
+    if (ret_host && q->host) {
+        strncpy(ret_host, q->host, hostlen);
+        ret_host[hostlen-1] = 0;
+    }
+
+    if (ret_serv && q->serv) {
+        strncpy(ret_serv, q->serv, servlen);
+        ret_serv[servlen-1] = 0;
+    }
+    
+    ret = q->ret;
+    asyncns_cancel(asyncns, q);
+
+    return ret;
+}
+
+static asyncns_query_t *
+asyncns_res(asyncns_t *asyncns, query_type_t qtype, 
+            const char *dname, int class, int type) {
+    uint8_t data[BUFSIZE];
+    res_request_t *req = (res_request_t*) data;
+    asyncns_query_t *q;
+    size_t dlen;
+
+    assert(asyncns);
+    assert(dname);
+
+    dlen = strlen(dname);
+
+    if (!(q = alloc_query(asyncns)))
+        return NULL;
+
+    memset(req, 0, sizeof(res_request_t));
+    
+    req->header.id = q->id;
+    req->header.type = q->type = qtype;
+    req->header.length = sizeof(res_request_t) + dlen + 1;
+
+    if (req->header.length > BUFSIZE)
+        goto fail;
+
+    req->class = class;
+    req->type = type;
+    req->dlen = dlen;
+
+    memcpy((uint8_t*) req + sizeof(res_request_t), dname, dlen + 1);
+
+    if (send(asyncns->fds[REQUEST_SEND_FD], req, req->header.length, 0) < 0)
+        goto fail;
+
+    return q;
+
+fail:
+    if (q)
+        asyncns_cancel(asyncns, q);
+
+    return NULL;
+}
+
+asyncns_query_t* asyncns_res_query(asyncns_t *asyncns, const char *dname, int class, int type) { 
+    return asyncns_res(asyncns, REQUEST_RES_QUERY, dname, class, type);
+}
+
+asyncns_query_t* asyncns_res_search(asyncns_t *asyncns, const char *dname, int class, int type) { 
+    return asyncns_res(asyncns, REQUEST_RES_SEARCH, dname, class, type);
+}
+
+int asyncns_res_done(asyncns_t *asyncns, asyncns_query_t* q, unsigned char **answer) {
+    int ret;
+    assert(asyncns);
+    assert(q);
+    assert(q->asyncns == asyncns);
+    assert(q->type == REQUEST_RES_QUERY || q->type == REQUEST_RES_SEARCH);
+    assert(answer);
+
+    if (!q->done)
+        return -EAGAIN;
+
+    *answer = (unsigned char *)q->serv;
+    q->serv = NULL;
+
+    ret = q->ret;
+
+    asyncns_cancel(asyncns, q);
+
+    return ret;
+}
+
+asyncns_query_t* asyncns_getnext(asyncns_t *asyncns) {
+    assert(asyncns);
+    return asyncns->done_head;
+}
+
+int asyncns_getnqueries(asyncns_t *asyncns) {
+    assert(asyncns);
+    return asyncns->n_queries;
+}
+
+void asyncns_cancel(asyncns_t *asyncns, asyncns_query_t* q) {
+    int i;
+    assert(asyncns);
+    assert(q);
+    assert(q->asyncns == asyncns);
+    assert(asyncns->n_queries > 0);
+
+    if (q->done) {
+
+        if (q->done_prev)
+            q->done_prev->done_next = q->done_next;
+        else 
+            asyncns->done_head = q->done_next;
+
+        if (q->done_next)
+            q->done_next->done_prev = q->done_prev;
+        else
+            asyncns->done_tail = q->done_prev;
+    }
+
+
+    i = q->id % MAX_QUERIES;
+    assert(asyncns->queries[i] == q);
+    asyncns->queries[i] = NULL;
+
+    asyncns_freeaddrinfo(q->addrinfo);
+    free(q->addrinfo);
+    free(q->host);
+    free(q->serv);
+
+    asyncns->n_queries--;
+    free(q);
+}
+
+void asyncns_freeaddrinfo(struct addrinfo *ai) {
+    if (!ai)
+        return;
+
+    while (ai) {
+        struct addrinfo *next = ai->ai_next;
+
+        free(ai->ai_addr);
+        free(ai->ai_canonname);
+        free(ai);
+
+        ai = next;
+    }
+}
+
+int asyncns_isdone(asyncns_t *asyncns, asyncns_query_t*q) {
+    assert(asyncns);
+    assert(q);
+    assert(q->asyncns == asyncns);
+
+    return q->done;
+}
+
+void asyncns_setuserdata(asyncns_t *asyncns, asyncns_query_t *q, void *userdata) {
+    assert(q);
+    assert(asyncns);
+    assert(q->asyncns = asyncns);
+    
+    q->userdata = userdata;
+}
+
+void* asyncns_getuserdata(asyncns_t *asyncns, asyncns_query_t *q) {
+    assert(q);
+    assert(asyncns);
+    assert(q->asyncns = asyncns);
+
+    return q->userdata;
+}
+
+