net.c

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/*
 * net.c
 *
 * Network implementation
 * All network related functions are grouped here
 *
 * a Net::DNS like library for C
 *
 * (c) NLnet Labs, 2004-2006
 *
 * See the file LICENSE for the license
 */
 
#include <ldns/config.h>
 
#include <ldns/ldns.h>
 
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#include <sys/time.h>
#include <errno.h>
#include <fcntl.h>
#ifdef HAVE_POLL
#include <poll.h>
#endif
 
ldns_status
ldns_send(ldns_pkt **result_packet, ldns_resolver *r, const ldns_pkt *query_pkt)
{
        ldns_buffer *qb;
        ldns_status result;
        ldns_rdf *tsig_mac = NULL;
 
        qb = ldns_buffer_new(LDNS_MIN_BUFLEN);
 
        if (query_pkt && ldns_pkt_tsig(query_pkt)) {
                tsig_mac = ldns_rr_rdf(ldns_pkt_tsig(query_pkt), 3);
        }
 
        if (!query_pkt ||
            ldns_pkt2buffer_wire(qb, query_pkt) != LDNS_STATUS_OK) {
                result = LDNS_STATUS_ERR;
        } else {
                result = ldns_send_buffer(result_packet, r, qb, tsig_mac);
        }
 
        ldns_buffer_free(qb);
 
        return result;
}
 
/* code from rdata.c */
static struct sockaddr_storage *
ldns_rdf2native_sockaddr_storage_port(
                const ldns_rdf *rd, uint16_t port, size_t *size)
{
        struct sockaddr_storage *data;
        struct sockaddr_in  *data_in;
        struct sockaddr_in6 *data_in6;
 
        data = LDNS_MALLOC(struct sockaddr_storage);
        if (!data) {
                return NULL;
        }
        /* zero the structure for portability */
        memset(data, 0, sizeof(struct sockaddr_storage));
 
        switch(ldns_rdf_get_type(rd)) {
                case LDNS_RDF_TYPE_A:
#ifndef S_SPLINT_S
                        data->ss_family = AF_INET;
#endif
                        data_in = (struct sockaddr_in*) data;
                        data_in->sin_port = (in_port_t)htons(port);
                        memcpy(&(data_in->sin_addr), ldns_rdf_data(rd), ldns_rdf_size(rd));
                        *size = sizeof(struct sockaddr_in);
                        return data;
                case LDNS_RDF_TYPE_AAAA:
#ifndef S_SPLINT_S
                        data->ss_family = AF_INET6;
#endif
                        data_in6 = (struct sockaddr_in6*) data;
                        data_in6->sin6_port = (in_port_t)htons(port);
                        memcpy(&data_in6->sin6_addr, ldns_rdf_data(rd), ldns_rdf_size(rd));
                        *size = sizeof(struct sockaddr_in6);
                        return data;
                default:
                        LDNS_FREE(data);
                        return NULL;
        }
}
 
struct sockaddr_storage *
ldns_rdf2native_sockaddr_storage(
                const ldns_rdf *rd, uint16_t port, size_t *size)
{
        return ldns_rdf2native_sockaddr_storage_port(
                        rd, (port == 0 ? (uint16_t)LDNS_PORT : port), size);
}
 
static void
ldns_sock_nonblock(int sockfd)
{
#ifdef HAVE_FCNTL
        int flag;
        if((flag = fcntl(sockfd, F_GETFL)) != -1) {
                flag |= O_NONBLOCK;
                if(fcntl(sockfd, F_SETFL, flag) == -1) {
                        /* ignore error, continue blockingly */
                }
        }
#elif defined(HAVE_IOCTLSOCKET)
        unsigned long on = 1;
        if(ioctlsocket(sockfd, FIONBIO, &on) != 0) {
                /* ignore error, continue blockingly */
        }
#endif
}
 
static void
ldns_sock_block(int sockfd)
{
#ifdef HAVE_FCNTL
        int flag;
        if((flag = fcntl(sockfd, F_GETFL)) != -1) {
                flag &= ~O_NONBLOCK;
                if(fcntl(sockfd, F_SETFL, flag) == -1) {
                        /* ignore error, continue */
                }
        }
#elif defined(HAVE_IOCTLSOCKET)
        unsigned long off = 0;
        if(ioctlsocket(sockfd, FIONBIO, &off) != 0) {
                /* ignore error, continue */
        }
#endif
}
 
static int
ldns_sock_wait(int sockfd, struct timeval timeout, int write)
{
        int ret;
#ifndef HAVE_POLL
#ifndef S_SPLINT_S
        fd_set fds;
        FD_ZERO(&fds);
        FD_SET(FD_SET_T sockfd, &fds);
        if(write)
                ret = select(sockfd+1, NULL, &fds, NULL, &timeout);
        else
                ret = select(sockfd+1, &fds, NULL, NULL, &timeout);
#endif
#else
        struct pollfd pfds[2];
 
        memset(&pfds[0], 0, sizeof(pfds[0]) * 2);
 
        pfds[0].fd = sockfd;
        pfds[0].events = POLLIN|POLLERR;
 
        if (write) {
                pfds[0].events |= POLLOUT;
        }
        
        ret = poll(pfds, 1, (int)(timeout.tv_sec * 1000
                                + timeout.tv_usec / 1000));
#endif
        if(ret == 0)
                /* timeout expired */
                return 0;
        else if(ret == -1)
                /* error */
                return 0;
        return 1;
}
 
 
static int
ldns_tcp_connect_from(const struct sockaddr_storage *to, socklen_t tolen, 
                const struct sockaddr_storage *from, socklen_t fromlen,
                struct timeval timeout)
{
        int sockfd;
 
#ifndef S_SPLINT_S
        if ((sockfd = socket((int)((struct sockaddr*)to)->sa_family, SOCK_STREAM, 
                                        IPPROTO_TCP)) == SOCK_INVALID) {
                return 0;
        }
#endif
        if (from && bind(sockfd, (const struct sockaddr*)from, fromlen) == SOCK_INVALID){
                return 0;
        }
 
        /* perform nonblocking connect, to be able to wait with select() */
        ldns_sock_nonblock(sockfd);
        if (connect(sockfd, (struct sockaddr*)to, tolen) == SOCK_INVALID) {
#ifndef USE_WINSOCK
#ifdef EINPROGRESS
                if(errno != EINPROGRESS) {
#else
                if(1) {
#endif
                        close_socket(sockfd);
                        return 0;
                }
#else /* USE_WINSOCK */
                if(WSAGetLastError() != WSAEINPROGRESS &&
                        WSAGetLastError() != WSAEWOULDBLOCK) {
                        close_socket(sockfd);
                        return 0;
                }
#endif
                /* error was only telling us that it would block */
        }
 
        /* wait(write) until connected or error */
        while(1) {
                int error = 0;
                socklen_t len = (socklen_t)sizeof(error);
 
                if(!ldns_sock_wait(sockfd, timeout, 1)) {
                        close_socket(sockfd);
                        return 0;
                }
 
                /* check if there is a pending error for nonblocking connect */
                if(getsockopt(sockfd, SOL_SOCKET, SO_ERROR, (void*)&error,
                        &len) < 0) {
#ifndef USE_WINSOCK
                        error = errno; /* on solaris errno is error */
#else
                        error = WSAGetLastError();
#endif
                }
#ifndef USE_WINSOCK
#if defined(EINPROGRESS) && defined(EWOULDBLOCK)
                if(error == EINPROGRESS || error == EWOULDBLOCK)
                        continue; /* try again */
#endif
                else if(error != 0) {
                        close_socket(sockfd);
                        /* error in errno for our user */
                        errno = error;
                        return 0;
                }
#else /* USE_WINSOCK */
                if(error == WSAEINPROGRESS)
                        continue;
                else if(error == WSAEWOULDBLOCK)
                        continue;
                else if(error != 0) {
                        close_socket(sockfd);
                        errno = error;
                        return 0;
                }
#endif /* USE_WINSOCK */
                /* connected */
                break;
        }
 
        /* set the socket blocking again */
        ldns_sock_block(sockfd);
 
        return sockfd;
}
 
int
ldns_tcp_connect(const struct sockaddr_storage *to, socklen_t tolen, 
                struct timeval timeout)
{
        return ldns_tcp_connect_from(to, tolen, NULL, 0, timeout);
}
 
static int
ldns_tcp_bgsend_from(ldns_buffer *qbin,
                const struct sockaddr_storage *to, socklen_t tolen, 
                const struct sockaddr_storage *from, socklen_t fromlen,
                struct timeval timeout)
{
        int sockfd;
        
        sockfd = ldns_tcp_connect_from(to, tolen, from, fromlen, timeout);
        
        if (sockfd == 0) {
                return 0;
        }
        
        if (ldns_tcp_send_query(qbin, sockfd, to, tolen) == 0) {
                close_socket(sockfd);
                return 0;
        }
        
        return sockfd;
}
 
int
ldns_tcp_bgsend(ldns_buffer *qbin,
                const struct sockaddr_storage *to, socklen_t tolen, 
                struct timeval timeout)
{
        return ldns_tcp_bgsend_from(qbin, to, tolen, NULL, 0, timeout);
}
 
 
/* keep in mind that in DNS tcp messages the first 2 bytes signal the
 * amount data to expect
 */
static ldns_status
ldns_tcp_send_from(uint8_t **result,  ldns_buffer *qbin,
                const struct sockaddr_storage *to, socklen_t tolen,
                const struct sockaddr_storage *from, socklen_t fromlen,
                struct timeval timeout, size_t *answer_size)
{
        int sockfd;
        uint8_t *answer;
        
        sockfd = ldns_tcp_bgsend_from(qbin, to, tolen, from, fromlen, timeout);
        
        if (sockfd == 0) {
                return LDNS_STATUS_ERR;
        }
 
        answer = ldns_tcp_read_wire_timeout(sockfd, answer_size, timeout);
        close_socket(sockfd);
 
        if (*answer_size == 0) {
                /* oops */
                return LDNS_STATUS_NETWORK_ERR;
        }
 
        /* resize accordingly */
        *result = LDNS_XREALLOC(answer, uint8_t, (size_t)*answer_size);
        if(!*result) {
                LDNS_FREE(answer);
                return LDNS_STATUS_MEM_ERR;
        }
        return LDNS_STATUS_OK;
}
 
ldns_status
ldns_tcp_send(uint8_t **result,  ldns_buffer *qbin,
                const struct sockaddr_storage *to, socklen_t tolen,
                struct timeval timeout, size_t *answer_size)
{
        return ldns_tcp_send_from(result, qbin,
                        to, tolen, NULL, 0, timeout, answer_size);
}
 
int
ldns_udp_connect(const struct sockaddr_storage *to, struct timeval ATTR_UNUSED(timeout))
{
        int sockfd;
 
#ifndef S_SPLINT_S
        if ((sockfd = socket((int)((struct sockaddr*)to)->sa_family, SOCK_DGRAM, 
                                        IPPROTO_UDP)) 
                        == -1) {
                return 0;
        }
#endif
        return sockfd;
}
 
static int
ldns_udp_bgsend_from(ldns_buffer *qbin,
                const struct sockaddr_storage *to  , socklen_t tolen, 
                const struct sockaddr_storage *from, socklen_t fromlen, 
                struct timeval timeout)
{
        int sockfd;
 
        sockfd = ldns_udp_connect(to, timeout);
 
        if (sockfd == 0) {
                return 0;
        }
 
        if (from && bind(sockfd, (const struct sockaddr*)from, fromlen) == -1){
                return 0;
        }
 
        if (ldns_udp_send_query(qbin, sockfd, to, tolen) == 0) {
                close_socket(sockfd);
                return 0;
        }
        return sockfd;
}
 
int
ldns_udp_bgsend(ldns_buffer *qbin,
                const struct sockaddr_storage *to  , socklen_t tolen, 
                struct timeval timeout)
{
        return ldns_udp_bgsend_from(qbin, to, tolen, NULL, 0, timeout);
}
 
static ldns_status
ldns_udp_send_from(uint8_t **result, ldns_buffer *qbin,
                const struct sockaddr_storage *to  , socklen_t tolen,
                const struct sockaddr_storage *from, socklen_t fromlen,
                struct timeval timeout, size_t *answer_size)
{
        int sockfd;
        uint8_t *answer;
 
        sockfd = ldns_udp_bgsend_from(qbin, to, tolen, from, fromlen, timeout);
 
        if (sockfd == 0) {
                return LDNS_STATUS_SOCKET_ERROR;
        }
 
        /* wait for an response*/
        if(!ldns_sock_wait(sockfd, timeout, 0)) {
                close_socket(sockfd);
                return LDNS_STATUS_NETWORK_ERR;
        }
 
        /* set to nonblocking, so if the checksum is bad, it becomes
         * an EGAIN error and the ldns_udp_send function does not block,
         * but returns a 'NETWORK_ERROR' much like a timeout. */
        ldns_sock_nonblock(sockfd);
 
        answer = ldns_udp_read_wire(sockfd, answer_size, NULL, NULL);
        close_socket(sockfd);
 
        if (*answer_size == 0) {
                /* oops */
                return LDNS_STATUS_NETWORK_ERR;
        }
 
        *result = answer;
        return LDNS_STATUS_OK;
}
 
ldns_status
ldns_udp_send(uint8_t **result, ldns_buffer *qbin,
                const struct sockaddr_storage *to  , socklen_t tolen,
                struct timeval timeout, size_t *answer_size)
{
        return ldns_udp_send_from(result, qbin, to, tolen, NULL, 0,
                        timeout, answer_size);
}
 
ldns_status
ldns_send_buffer(ldns_pkt **result, ldns_resolver *r, ldns_buffer *qb, ldns_rdf *tsig_mac)
{
        uint8_t i;
 
        struct sockaddr_storage *src = NULL;
        size_t src_len;
        struct sockaddr_storage *ns;
        size_t ns_len;
        struct timeval tv_s;
        struct timeval tv_e;
 
        ldns_rdf **ns_array;
        size_t *rtt;
        ldns_pkt *reply;
        bool all_servers_rtt_inf;
        uint8_t retries;
 
        uint8_t *reply_bytes = NULL;
        size_t reply_size = 0;
        ldns_status status, send_status;
 
        assert(r != NULL);
 
        /* The query should at least have one question */
        if(ldns_buffer_limit(qb) < 6 || ldns_buffer_read_u16_at(qb, 4) != 1)
                return LDNS_STATUS_QDCOUNT_MUST_BE_ONE;
 
        status = LDNS_STATUS_OK;
        rtt = ldns_resolver_rtt(r);
        ns_array = ldns_resolver_nameservers(r);
        reply = NULL; 
        ns_len = 0;
 
        all_servers_rtt_inf = true;
 
        if (ldns_resolver_random(r)) {
                ldns_resolver_nameservers_randomize(r);
        }
 
        if(ldns_resolver_source(r)) {
                src = ldns_rdf2native_sockaddr_storage_port(
                                ldns_resolver_source(r), 0, &src_len);
        }
 
        /* loop through all defined nameservers */
        for (i = 0; i < ldns_resolver_nameserver_count(r); i++) {
                if (rtt[i] == LDNS_RESOLV_RTT_INF) {
                        /* not reachable nameserver! */
                        continue;
                }
 
                /* maybe verbosity setting?
                printf("Sending to ");
                ldns_rdf_print(stdout, ns_array[i]);
                printf("\n");
                */
                ns = ldns_rdf2native_sockaddr_storage(ns_array[i],
                                ldns_resolver_port(r), &ns_len);
 
 
#ifndef S_SPLINT_S
                if ((ns->ss_family == AF_INET) &&
                                (ldns_resolver_ip6(r) == LDNS_RESOLV_INET6)) {
                        /* not reachable */
                        LDNS_FREE(ns);
                        continue;
                }
 
                if ((ns->ss_family == AF_INET6) &&
                                 (ldns_resolver_ip6(r) == LDNS_RESOLV_INET)) {
                        /* not reachable */
                        LDNS_FREE(ns);
                        continue;
                }
#endif
 
                all_servers_rtt_inf = false;
 
                gettimeofday(&tv_s, NULL);
 
                send_status = LDNS_STATUS_ERR;
 
                /* reply_bytes implicitly handles our error */
                if (ldns_resolver_usevc(r)) {
                        for (retries = ldns_resolver_retry(r); retries > 0; retries--) {
                                send_status = 
                                        ldns_tcp_send_from(&reply_bytes, qb, 
                                                ns, (socklen_t)ns_len,
                                                src, (socklen_t)src_len,
                                                ldns_resolver_timeout(r),
                                                &reply_size);
                                if (send_status == LDNS_STATUS_OK) {
                                        break;
                                }
                        }
                } else {
                        for (retries = ldns_resolver_retry(r); retries > 0; retries--) {
                                /* ldns_rdf_print(stdout, ns_array[i]); */
                                send_status = 
                                        ldns_udp_send_from(&reply_bytes, qb,
                                                ns,  (socklen_t)ns_len,
                                                src, (socklen_t)src_len,
                                                ldns_resolver_timeout(r),
                                                &reply_size);
                                if (send_status == LDNS_STATUS_OK) {
                                        break;
                                }
                        }
                }
 
                if (send_status != LDNS_STATUS_OK) {
                        ldns_resolver_set_nameserver_rtt(r, i, LDNS_RESOLV_RTT_INF);
                        status = send_status;
                }
                
                /* obey the fail directive */
                if (!reply_bytes) {
                        /* the current nameserver seems to have a problem, blacklist it */
                        if (ldns_resolver_fail(r)) {
                                LDNS_FREE(ns);
                                return status ? status : LDNS_STATUS_ERR;
                        } else {
                                LDNS_FREE(ns);
                                continue;
                        }
                } 
                
                status = ldns_wire2pkt(&reply, reply_bytes, reply_size);
                if (status != LDNS_STATUS_OK) {
                        LDNS_FREE(reply_bytes);
                        LDNS_FREE(ns);
                        return status;
                }
                
                LDNS_FREE(ns);
                gettimeofday(&tv_e, NULL);
 
                if (reply) {
                        ldns_pkt_set_querytime(reply, (uint32_t)
                                ((tv_e.tv_sec - tv_s.tv_sec) * 1000) +
                                (tv_e.tv_usec - tv_s.tv_usec) / 1000);
                        ldns_pkt_set_answerfrom(reply,
                                        ldns_rdf_clone(ns_array[i]));
                        ldns_pkt_set_timestamp(reply, tv_s);
                        ldns_pkt_set_size(reply, reply_size);
                        break;
                } else {
                        if (ldns_resolver_fail(r)) {
                                /* if fail is set bail out, after the first
                                 * one */
                                break;
                        }
                }
 
                /* wait retrans seconds... */
                sleep((unsigned int) ldns_resolver_retrans(r));
        }
 
        if(src) {
                LDNS_FREE(src);
        }
        if (all_servers_rtt_inf) {
                LDNS_FREE(reply_bytes);
                return LDNS_STATUS_RES_NO_NS;
        }
#ifdef HAVE_SSL
        if (tsig_mac && reply && reply_bytes) {
                if (!ldns_pkt_tsig_verify(reply,
                                          reply_bytes,
                                          reply_size,
                                          ldns_resolver_tsig_keyname(r),
                                          ldns_resolver_tsig_keydata(r), tsig_mac)) {
                        status = LDNS_STATUS_CRYPTO_TSIG_BOGUS;
                }
        }
#else
        (void)tsig_mac;
#endif /* HAVE_SSL */
 
        LDNS_FREE(reply_bytes);
        if (reply) {
                ldns_pkt *query = NULL;
 
                if(ldns_pkt_qdcount(reply) != 1) {
                        status = LDNS_STATUS_QDCOUNT_MUST_BE_ONE;
                        ldns_pkt_free(reply);
                        reply = NULL;
 
                } else if(ldns_wire2pkt(&query
                                , ldns_buffer_begin(qb)
                                , ldns_buffer_position(qb)) != LDNS_STATUS_OK
                || ldns_pkt_qdcount(query) != 1
                || ldns_rr_compare(ldns_rr_list_rr(ldns_pkt_question(query),0)
                                  ,ldns_rr_list_rr(ldns_pkt_question(reply),0))){
                        status = LDNS_STATUS_QUERY_DID_NOT_MATCH;
                        ldns_pkt_free(reply);
                        reply = NULL;
                }
                ldns_pkt_free(query);
        }
        if (result) {
                *result = reply;
        }
 
        return status;
}
 
ssize_t
ldns_tcp_send_query(ldns_buffer *qbin, int sockfd, 
                    const struct sockaddr_storage *to, socklen_t tolen)
{
        uint8_t *sendbuf;
        ssize_t bytes;
 
        /* add length of packet */
        sendbuf = LDNS_XMALLOC(uint8_t, ldns_buffer_position(qbin) + 2);
        if(!sendbuf) return 0;
        ldns_write_uint16(sendbuf, ldns_buffer_position(qbin));
        memcpy(sendbuf + 2, ldns_buffer_begin(qbin), ldns_buffer_position(qbin));
 
        bytes = sendto(sockfd, (void*)sendbuf,
                        ldns_buffer_position(qbin) + 2, 0, (struct sockaddr *)to, tolen);
 
        LDNS_FREE(sendbuf);
 
        if (bytes == -1 || (size_t) bytes != ldns_buffer_position(qbin) + 2 ) {
                return 0;
        }
        return bytes;
}
 
/* don't wait for an answer */
ssize_t
ldns_udp_send_query(ldns_buffer *qbin, int sockfd, const struct sockaddr_storage *to, 
                socklen_t tolen)
{
        ssize_t bytes;
 
        bytes = sendto(sockfd, (void*)ldns_buffer_begin(qbin),
                        ldns_buffer_position(qbin), 0, (struct sockaddr *)to, tolen);
 
        if (bytes == -1 || (size_t)bytes != ldns_buffer_position(qbin)) {
                return 0;
        }
        if ((size_t) bytes != ldns_buffer_position(qbin)) {
                return 0;
        }
        return bytes;
}
 
uint8_t *
ldns_udp_read_wire(int sockfd, size_t *size, struct sockaddr_storage *from,
                socklen_t *fromlen)
{
        uint8_t *wire, *wireout;
        ssize_t wire_size;
 
        wire = LDNS_XMALLOC(uint8_t, LDNS_MAX_PACKETLEN);
        if (!wire) {
                *size = 0;
                return NULL;
        }
 
        wire_size = recvfrom(sockfd, (void*)wire, LDNS_MAX_PACKETLEN, 0, 
                        (struct sockaddr *)from, fromlen);
 
        /* recvfrom can also return 0 */
        if (wire_size == -1 || wire_size == 0) {
                *size = 0;
                LDNS_FREE(wire);
                return NULL;
        }
 
        *size = (size_t)wire_size;
        wireout = LDNS_XREALLOC(wire, uint8_t, (size_t)wire_size);
        if(!wireout) LDNS_FREE(wire);
 
        return wireout;
}
 
uint8_t *
ldns_tcp_read_wire_timeout(int sockfd, size_t *size, struct timeval timeout)
{
        uint8_t *wire;
        uint16_t wire_size;
        ssize_t bytes = 0, rc = 0;
 
        wire = LDNS_XMALLOC(uint8_t, 2);
        if (!wire) {
                *size = 0;
                return NULL;
        }
        
        while (bytes < 2) {
                if(!ldns_sock_wait(sockfd, timeout, 0)) {
                        *size = 0;
                        LDNS_FREE(wire);
                        return NULL;
                }
                rc = recv(sockfd, (void*) (wire + bytes), 
                                (size_t) (2 - bytes), 0);
                if (rc == -1 || rc == 0) {
                        *size = 0;
                        LDNS_FREE(wire);
                        return NULL;
                }
                bytes += rc;
        }
 
        wire_size = ldns_read_uint16(wire);
        
        LDNS_FREE(wire);
        wire = LDNS_XMALLOC(uint8_t, wire_size);
        if (!wire) {
                *size = 0;
                return NULL;
        }
        bytes = 0;
 
        while (bytes < (ssize_t) wire_size) {
                if(!ldns_sock_wait(sockfd, timeout, 0)) {
                        *size = 0;
                        LDNS_FREE(wire);
                        return NULL;
                }
                rc = recv(sockfd, (void*) (wire + bytes), 
                                (size_t) (wire_size - bytes), 0);
                if (rc == -1 || rc == 0) {
                        LDNS_FREE(wire);
                        *size = 0;
                        return NULL;
                }
                bytes += rc;
        }
        
        *size = (size_t) bytes;
        return wire;
}
 
uint8_t *
ldns_tcp_read_wire(int sockfd, size_t *size)
{
        uint8_t *wire;
        uint16_t wire_size;
        ssize_t bytes = 0, rc = 0;
 
        wire = LDNS_XMALLOC(uint8_t, 2);
        if (!wire) {
                *size = 0;
                return NULL;
        }
        
        while (bytes < 2) {
                rc = recv(sockfd, (void*) (wire + bytes), 
                                (size_t) (2 - bytes), 0);
                if (rc == -1 || rc == 0) {
                        *size = 0;
                        LDNS_FREE(wire);
                        return NULL;
                }
                bytes += rc;
        }
 
        wire_size = ldns_read_uint16(wire);
        
        LDNS_FREE(wire);
        wire = LDNS_XMALLOC(uint8_t, wire_size);
        if (!wire) {
                *size = 0;
                return NULL;
        }
        bytes = 0;
 
        while (bytes < (ssize_t) wire_size) {
                rc = recv(sockfd, (void*) (wire + bytes), 
                                (size_t) (wire_size - bytes), 0);
                if (rc == -1 || rc == 0) {
                        LDNS_FREE(wire);
                        *size = 0;
                        return NULL;
                }
                bytes += rc;
        }
        
        *size = (size_t) bytes;
        return wire;
}
 
#ifndef S_SPLINT_S
ldns_rdf *
ldns_sockaddr_storage2rdf(const struct sockaddr_storage *sock, uint16_t *port)
{
        ldns_rdf *addr;
        struct sockaddr_in *data_in;
        struct sockaddr_in6 *data_in6;
 
        switch(sock->ss_family) {
                case AF_INET:
                        data_in = (struct sockaddr_in*)sock;
                        if (port) {
                                *port = ntohs((uint16_t)data_in->sin_port);
                        }
                        addr = ldns_rdf_new_frm_data(LDNS_RDF_TYPE_A,
                                        LDNS_IP4ADDRLEN, &data_in->sin_addr);
                        break;
                case AF_INET6:
                        data_in6 = (struct sockaddr_in6*)sock;
                        if (port) {
                                *port = ntohs((uint16_t)data_in6->sin6_port);
                        }
                        addr = ldns_rdf_new_frm_data(LDNS_RDF_TYPE_AAAA,
                                        LDNS_IP6ADDRLEN, &data_in6->sin6_addr);
                        break;
                default:
                        if (port) {
                                *port = 0;
                        }
                        return NULL;
        }
        return addr;
}
#endif
 
/* code from resolver.c */
ldns_status
ldns_axfr_start(ldns_resolver *resolver, const ldns_rdf *domain, ldns_rr_class class) 
{
        ldns_pkt *query;
        ldns_buffer *query_wire;
 
        struct sockaddr_storage *src = NULL;
        size_t src_len = 0;
        struct sockaddr_storage *ns = NULL;
        size_t ns_len = 0;
        size_t ns_i;
        ldns_status status;
 
        if (!resolver || ldns_resolver_nameserver_count(resolver) < 1) {
                return LDNS_STATUS_ERR;
        }
 
        query = ldns_pkt_query_new(ldns_rdf_clone(domain), LDNS_RR_TYPE_AXFR, class, 0);
 
        if (!query) {
                return LDNS_STATUS_ADDRESS_ERR;
        }
        if(ldns_resolver_source(resolver)) {
                src = ldns_rdf2native_sockaddr_storage_port(
                                ldns_resolver_source(resolver), 0, &src_len);
        }
        /* For AXFR, we have to make the connection ourselves */
        /* try all nameservers (which usually would mean v4 fallback if
         * @hostname is used */
        for (ns_i = 0;
             ns_i < ldns_resolver_nameserver_count(resolver) &&
             resolver->_socket == SOCK_INVALID;
             ns_i++) {
                if (ns != NULL) {
                        LDNS_FREE(ns);
                }
                ns = ldns_rdf2native_sockaddr_storage(
                        resolver->_nameservers[ns_i],
                        ldns_resolver_port(resolver), &ns_len);
#ifndef S_SPLINT_S
                if ((ns->ss_family == AF_INET) &&
                        (ldns_resolver_ip6(resolver) == LDNS_RESOLV_INET6)) {
                        /* not reachable */
                        LDNS_FREE(ns);
                        ns = NULL;
                        continue;
                }
 
                if ((ns->ss_family == AF_INET6) &&
                         (ldns_resolver_ip6(resolver) == LDNS_RESOLV_INET)) {
                        /* not reachable */
                        LDNS_FREE(ns);
                        ns = NULL;
                        continue;
                }
#endif
 
                resolver->_socket = ldns_tcp_connect_from(
                                ns, (socklen_t)ns_len,
                                src, (socklen_t)src_len,
                                ldns_resolver_timeout(resolver));
        }
 
        if (resolver->_socket == SOCK_INVALID) {
                ldns_pkt_free(query);
                LDNS_FREE(ns);
                return LDNS_STATUS_NETWORK_ERR;
        }
 
#ifdef HAVE_SSL
        if (ldns_resolver_tsig_keyname(resolver) && ldns_resolver_tsig_keydata(resolver)) {
                status = ldns_pkt_tsig_sign(query,
                                            ldns_resolver_tsig_keyname(resolver),
                                            ldns_resolver_tsig_keydata(resolver),
                                            300, ldns_resolver_tsig_algorithm(resolver), NULL);
                if (status != LDNS_STATUS_OK) {
                        /* to prevent problems on subsequent calls to 
                         * ldns_axfr_start we have to close the socket here! */
                        close_socket(resolver->_socket);
                        resolver->_socket = 0;
 
                        ldns_pkt_free(query);
                        LDNS_FREE(ns);
 
                        return LDNS_STATUS_CRYPTO_TSIG_ERR;
                }
        }
#endif /* HAVE_SSL */
 
        /* Convert the query to a buffer
         * Is this necessary?
         */
        query_wire = ldns_buffer_new(LDNS_MAX_PACKETLEN);
        if(!query_wire) {
                ldns_pkt_free(query);
                LDNS_FREE(ns);
 
                close_socket(resolver->_socket);
 
                return LDNS_STATUS_MEM_ERR;
        }
        status = ldns_pkt2buffer_wire(query_wire, query);
        if (status != LDNS_STATUS_OK) {
                ldns_pkt_free(query);
                ldns_buffer_free(query_wire);
                LDNS_FREE(ns);
 
                /* to prevent problems on subsequent calls to ldns_axfr_start
                 * we have to close the socket here! */
                close_socket(resolver->_socket);
                resolver->_socket = 0;
 
                return status;
        }
        /* Send the query */
        if (ldns_tcp_send_query(query_wire, resolver->_socket, ns,
                                (socklen_t)ns_len) == 0) {
                ldns_pkt_free(query);
                ldns_buffer_free(query_wire);
                LDNS_FREE(ns);
 
                /* to prevent problems on subsequent calls to ldns_axfr_start
                 * we have to close the socket here! */
 
 
                close_socket(resolver->_socket);
 
                return LDNS_STATUS_NETWORK_ERR;
        }
 
        ldns_pkt_free(query);
        ldns_buffer_free(query_wire);
        LDNS_FREE(ns);
 
        /*
         * The AXFR is done once the second SOA record is sent
         */
        resolver->_axfr_soa_count = 0;
        return LDNS_STATUS_OK;
}