firstHEADmain

17 files changed, 2288 insertions, 0 deletions

diff --git a/src/client/addr.c b/src/client/addr.c
new file mode 100644
index 0000000..82f0e2e
--- /dev/null
+++ b/src/client/addr.c
@@ -0,0 +1,254 @@
+#include <errno.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <netdb.h>
+#include <poll.h>
+
+#include "addr.h"
+
+void create_ip_addr(uint8_t* domain, IpAddr* addr) {
+    addr->type = V4;
+    memcpy(&addr->data.v4, domain, 4);
+}
+
+void create_ip_addr6(uint8_t* domain, IpAddr* addr) {
+    addr->type = V6;
+    memcpy(&addr->data.v6, domain, 16);
+}
+
+void ip_addr_any(IpAddr* addr) {
+    addr->type = V4;
+    addr->data.v4.s_addr = htonl(INADDR_ANY);
+}
+
+void ip_addr_any6(IpAddr* addr) {
+    addr->type = V6;
+    addr->data.v6 = in6addr_any;
+}
+
+bool ip_addr_name(const char* hostname, IpAddr* addr) {
+
+    struct hostent *he;
+	struct in_addr **addr_list;
+	int i;
+		
+	if ((he = gethostbyname(hostname)) == NULL) {
+		return false;
+	}
+
+	addr_list = (struct in_addr **) he->h_addr_list;
+	
+	for(i = 0; addr_list[i] != NULL; i++) {
+		addr->data.v4 = *addr_list[i];
+        addr->type = V4;
+		return true;
+	}
+
+	return false;
+}
+
+static struct sockaddr_in create_socket_addr_v4(IpAddr addr, uint16_t port) {
+    struct sockaddr_in socketaddr;
+    memset(&socketaddr, 0, sizeof(socketaddr));
+    socketaddr.sin_family = AF_INET;
+    socketaddr.sin_port = htons(port);
+    socketaddr.sin_addr = addr.data.v4;
+    return socketaddr;
+}
+
+static struct sockaddr_in6 create_socket_addr_v6(IpAddr addr, uint16_t port) {
+    struct sockaddr_in6 socketaddr;
+    memset(&socketaddr, 0, sizeof(socketaddr));
+    socketaddr.sin6_family = AF_INET6;
+    socketaddr.sin6_port = htons(port);
+    socketaddr.sin6_addr = addr.data.v6;
+    return socketaddr;
+}
+
+static size_t get_addr_len(AddrType type) {
+    if (type == V4) {
+        return sizeof(struct sockaddr_in);
+    } else if (type == V6) {
+        return sizeof(struct sockaddr_in6);
+    } else {
+        return 0;
+    }
+}
+
+void create_socket_addr(uint16_t port, IpAddr addr, SocketAddr* socket) {
+    socket->type = addr.type;
+    if (addr.type == V4) {
+        socket->data.v4 = create_socket_addr_v4(addr, port);
+    } else if(addr.type == V6) {
+        socket->data.v6 = create_socket_addr_v6(addr, port);
+    } else {
+        exit(EXIT_FAILURE);
+    }
+    socket->len = get_addr_len(addr.type);
+}
+
+#define ADDR_DOMAIN(addr, var) \
+    struct sockaddr* var; \
+    if (addr->type == V4) { \
+        var = (struct sockaddr*) &addr->data.v4; \
+    } else if (addr->type == V6) { \
+        var = (struct sockaddr*) &addr->data.v6; \
+    } else { \
+        return -1; \
+    }
+
+#define ADDR_AFNET(type, var) \
+    int var; \
+    if (type == V4) { \
+        var = AF_INET; \
+    } else if (type == V6) { \
+        var = AF_INET6; \
+    } else { \
+        return -1; \
+    }
+
+int32_t create_udp_socket(AddrType type, UdpSocket* sock) {
+    ADDR_AFNET(type, __domain)
+    sock->type = type;
+    sock->sockfd = socket(__domain, SOCK_DGRAM, 0);
+    return sock->sockfd;
+}
+
+int32_t bind_udp_socket(SocketAddr* addr, UdpSocket* sock) {
+    if (addr->type == V6) {
+        int v6OnlyEnabled = 0;
+        int32_t res = setsockopt(
+            sock->sockfd, 
+            IPPROTO_IPV6, 
+            IPV6_V6ONLY, 
+            &v6OnlyEnabled, 
+            sizeof(v6OnlyEnabled)
+        );
+        if (res < 0) return res;
+    }
+    ADDR_DOMAIN(addr, __addr)
+    return bind(sock->sockfd, __addr, addr->len);
+}
+
+static bool timeout (int connfd, int ms) {
+    struct pollfd fd;
+    int res;
+
+    fd.fd = connfd;
+    fd.events = POLLIN;
+    res = poll(&fd, 1, ms);
+    return res == 0;
+}
+
+int32_t read_udp_socket(UdpSocket* socket, void* buffer, uint16_t len, SocketAddr* clientaddr) {
+    clientaddr->type = socket->type;
+    clientaddr->len = get_addr_len(socket->type); 
+    ADDR_DOMAIN(clientaddr, __addr)
+    if (timeout(socket->sockfd, 1000)) {
+        errno = ETIMEDOUT;
+        return -1;
+    }
+    return recvfrom(
+        socket->sockfd, 
+        buffer, 
+        (size_t) len,
+        MSG_WAITALL, 
+        __addr,
+        (uint32_t*) &clientaddr->len
+    );
+}
+
+int32_t write_udp_socket(UdpSocket* socket, void* buffer, uint16_t len, SocketAddr* clientaddr) {
+    ADDR_DOMAIN(clientaddr, __addr)
+    return sendto(
+        socket->sockfd, 
+        buffer,
+        (size_t) len,
+		MSG_CONFIRM,
+        __addr, 
+        (uint32_t) clientaddr->len
+    );
+}
+
+int32_t close_udp_socket(UdpSocket* socket) {
+    return close(socket->sockfd);
+}
+
+int32_t create_tcp_socket(AddrType type, TcpSocket* sock) {
+    ADDR_AFNET(type, __domain)
+    sock->type = type;
+    sock->sockfd = socket(__domain, SOCK_STREAM, 0);
+    return sock->sockfd;
+}
+
+int32_t bind_tcp_socket(SocketAddr* addr, TcpSocket* sock) {
+    if (addr->type == V6) {
+        int v6OnlyEnabled = 0;
+        int32_t res = setsockopt(
+            sock->sockfd, 
+            IPPROTO_IPV6, 
+            IPV6_V6ONLY, 
+            &v6OnlyEnabled, 
+            sizeof(v6OnlyEnabled)
+        );
+        if (res < 0) return res;
+    }
+    ADDR_DOMAIN(addr, __addr)
+    return bind(sock->sockfd, __addr, addr->len);
+}
+
+int32_t listen_tcp_socket(TcpSocket* socket, uint32_t max) {
+    return listen(socket->sockfd, max);
+}
+
+int32_t accept_tcp_socket(TcpSocket* socket, TcpStream* stream) {
+    stream->clientaddr.type = socket->type;
+    memset(&stream->clientaddr, 0, sizeof(SocketAddr));
+    SocketAddr* addr = &stream->clientaddr;
+    ADDR_DOMAIN(addr, __addr)
+    stream->streamfd = accept(
+        socket->sockfd,
+        __addr,
+        (uint32_t*) &stream->clientaddr.len
+    );
+    return stream->streamfd;
+}
+
+int32_t close_tcp_socket(TcpSocket* socket) {
+    return close(socket->sockfd);
+}
+
+int32_t connect_tcp_stream(SocketAddr* servaddr, TcpStream* stream) {
+    TcpSocket socket;    
+    int32_t res = create_tcp_socket(servaddr->type, &socket);
+    if (res < 0) return res;
+    stream->clientaddr = *servaddr;
+    stream->streamfd = socket.sockfd;
+    ADDR_DOMAIN(servaddr, __addr)
+    return connect(
+        socket.sockfd, 
+        __addr, 
+        servaddr->len
+    );
+}
+
+int32_t read_tcp_stream(TcpStream* stream, void* buffer, uint16_t len) {
+    if (timeout(stream->streamfd, 3000)) {
+        errno = ETIMEDOUT;
+        return -1;
+    }
+    return recv(stream->streamfd, buffer, len, MSG_WAITALL);
+}
+
+int32_t write_tcp_stream(TcpStream* stream, void* buffer, uint16_t len) {
+    return send(stream->streamfd, buffer, len, MSG_NOSIGNAL);
+}
+
+int32_t close_tcp_stream(TcpStream* stream) {
+    return close(stream->streamfd);
+}
diff --git a/src/client/addr.h b/src/client/addr.h
new file mode 100644
index 0000000..28c6066
--- /dev/null
+++ b/src/client/addr.h
@@ -0,0 +1,69 @@
+#pragma once
+
+#include "../packet/record.h"
+
+#include <string.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+
+typedef enum {
+    V4,
+    V6
+} AddrType;
+
+typedef struct {
+    AddrType type;
+    union {
+        struct in_addr v4;
+        struct in6_addr v6;
+    } data;
+} IpAddr;
+
+void create_ip_addr(uint8_t* domain, IpAddr* addr);
+void create_ip_addr6(uint8_t* domain, IpAddr* addr);
+void ip_addr_any(IpAddr* addr);
+void ip_addr_any6(IpAddr* addr);
+bool ip_addr_name(const char* name, IpAddr* addr);
+
+typedef struct {
+    AddrType type;
+    union {
+        struct sockaddr_in v4;
+        struct sockaddr_in6 v6;
+    } data;
+    size_t len;
+} SocketAddr;
+
+void create_socket_addr(uint16_t port, IpAddr addr, SocketAddr* socket);
+
+typedef struct {
+    AddrType type;
+    uint32_t sockfd;
+} UdpSocket;
+
+int32_t create_udp_socket(AddrType type, UdpSocket* socket);
+int32_t bind_udp_socket(SocketAddr* addr, UdpSocket* socket);
+int32_t read_udp_socket(UdpSocket* socket, void* buffer, uint16_t len, SocketAddr* clientaddr);
+int32_t write_udp_socket(UdpSocket* socket, void* buffer, uint16_t len, SocketAddr* clientaddr);
+int32_t close_udp_socket(UdpSocket* socket);
+
+typedef struct {
+    AddrType type;
+    uint32_t sockfd;
+} TcpSocket;
+
+typedef struct {
+    SocketAddr clientaddr;
+    uint32_t streamfd;
+} TcpStream;
+
+int32_t create_tcp_socket(AddrType type, TcpSocket* socket);
+int32_t bind_tcp_socket(SocketAddr* addr, TcpSocket* socket);
+int32_t listen_tcp_socket(TcpSocket* socket, uint32_t max);
+int32_t accept_tcp_socket(TcpSocket* socket, TcpStream* stream);
+int32_t close_tcp_socket(TcpSocket* socket);
+int32_t connect_tcp_stream(SocketAddr* servaddr, TcpStream* stream);
+int32_t read_tcp_stream(TcpStream* stream, void* buffer, uint16_t len);
+int32_t write_tcp_stream(TcpStream* stream, void* buffer, uint16_t len);
+int32_t close_tcp_stream(TcpStream* stream);
diff --git a/src/client/binding.c b/src/client/binding.c
new file mode 100644
index 0000000..9917a50
--- /dev/null
+++ b/src/client/binding.c
@@ -0,0 +1,167 @@
+#include <ctype.h>
+#include <netinet/in.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include "addr.h"
+#include "binding.h"
+
+static void read_to_packet(uint8_t* buf, uint16_t len, Packet* packet) {
+    PacketBuffer* pkbuffer = buffer_create(len);
+    for (int i = 0; i < len; i++) { 
+        buffer_write(pkbuffer, buf[i]);
+    }
+    buffer_seek(pkbuffer, 0);
+    read_packet(pkbuffer, packet);
+    buffer_free(pkbuffer);
+}
+
+static bool read_udp(Connection* connection, Packet* packet) {
+    uint8_t buffer[512];
+    int32_t n = read_udp_socket(
+        &connection->sock.udp.udp, 
+        buffer,
+        512, 
+        &connection->sock.udp.clientaddr
+    );
+    if (n < 0) {
+        return false;
+    }
+    read_to_packet(buffer, n, packet);
+    return true;
+}
+
+static bool read_tcp(Connection* connection, Packet* packet) {
+    uint16_t len;
+    if ( read_tcp_stream(
+        &connection->sock.tcp, 
+        &len, 
+        sizeof(uint16_t)
+    ) < 2) {
+        return false;
+    }
+    len = ntohs(len);
+
+    uint8_t buffer[len];
+    if (read_tcp_stream(
+        &connection->sock.tcp, 
+        buffer, 
+        len
+    ) < len) {
+        return false;
+    }
+
+    read_to_packet(buffer, len, packet);
+    return true;
+}
+
+static bool read_connection(Connection* connection, Packet* packet) {
+    if (connection->type == UDP) {
+        return read_udp(connection, packet);
+    } else if (connection->type == TCP) {
+        return read_tcp(connection, packet);
+    }
+    return false;
+}
+
+static bool write_udp(Connection* connection, uint8_t* buf, uint16_t len) {
+    if (len > 512) {
+        buf[2] = buf[2] | 0x03;
+        len = 512;
+    }
+    return write_udp_socket(
+        &connection->sock.udp.udp, 
+        buf, 
+        len, 
+        &connection->sock.udp.clientaddr
+    ) == len;
+}
+
+static bool write_tcp(Connection* connection, uint8_t* buf, uint16_t len) {
+    uint16_t net_len = htons(len);
+    if (write_tcp_stream(
+        &connection->sock.tcp, 
+        &net_len, 
+        sizeof(uint16_t)
+    ) < 0) {
+        return false;
+    }
+    
+    if (write_tcp_stream(
+        &connection->sock.tcp, 
+        buf, 
+        len
+    ) < 0) {
+        return false;
+    }
+
+    return true;
+}
+
+static bool write_connection(Connection* connection, Packet* packet) {
+    PacketBuffer* pkbuffer = buffer_create(64);
+    write_packet(pkbuffer, packet);
+    uint16_t len = buffer_get_size(pkbuffer);
+    uint8_t* buffer = buffer_get_ptr(pkbuffer);
+    bool success = false;
+    if(connection->type == UDP) {
+        success = write_udp(connection, buffer, len);
+    } else if(connection->type == TCP) {
+        success = write_tcp(connection, buffer, len);
+    };
+    buffer_free(pkbuffer);
+    return success;
+}
+
+void free_connection(Connection* connection) {
+    if (connection->type == TCP) {
+        close_tcp_stream(&connection->sock.tcp);
+    }
+}
+
+static bool create_udp_request(SocketAddr* addr, Connection* request) {
+    if ( create_udp_socket(addr->type, &request->sock.udp.udp) < 0) {
+        return false;
+    }
+    request->sock.udp.clientaddr = *addr;
+    return true;
+}
+
+static bool create_tcp_request(SocketAddr* addr, Connection* request) {
+    if( connect_tcp_stream(addr, &request->sock.tcp) < 0) {
+        return false;
+    }
+    return true;
+}
+
+bool create_request(BindingType type, SocketAddr* addr, Connection* request) {
+    request->type = type;
+    if (type == UDP) {
+        return create_udp_request(addr, request);
+    } else if (type == TCP) {
+        return create_tcp_request(addr, request);
+    } else {
+        return true;
+    }
+}
+
+bool request_packet(Connection* request, Packet* in, Packet* out) {
+    if (!write_connection(request, in)) {
+        return false;
+    }
+    if (!read_connection(request, out)) {
+        return false;
+    }
+    return true;
+}
+
+void free_request(Connection* connection) {
+    if (connection->type == UDP) {
+        close_udp_socket(&connection->sock.udp.udp);
+    } else if (connection->type == TCP) {
+        close_tcp_stream(&connection->sock.tcp);
+    }
+}
diff --git a/src/client/binding.h b/src/client/binding.h
new file mode 100644
index 0000000..ea02c98
--- /dev/null
+++ b/src/client/binding.h
@@ -0,0 +1,26 @@
+#pragma once
+
+#include "../packet/packet.h"
+#include "addr.h"
+
+#include <netinet/in.h>
+
+typedef enum {
+    UDP,
+    TCP
+} BindingType;
+
+typedef struct {
+    BindingType type;
+    union {
+        struct {
+            UdpSocket udp;
+            SocketAddr clientaddr;
+        } udp;
+        TcpStream tcp;
+    } sock;
+} Connection;
+
+bool create_request(BindingType type, SocketAddr* addr, Connection* request);
+bool request_packet(Connection* request, Packet* in, Packet* out);
+void free_request(Connection* connection);
diff --git a/src/client/client.c b/src/client/client.c
new file mode 100644
index 0000000..31ef589
--- /dev/null
+++ b/src/client/client.c
@@ -0,0 +1,177 @@
+#include "client.h"
+#include "../packet/question.h"
+#include "addr.h"
+#include "binding.h"
+
+#include <resolv.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <string.h>
+#include <time.h>
+#include <errno.h>
+#include <sys/time.h>
+
+void resolve_default_server(IpAddr* addr) {
+    res_init();
+    addr->data.v4 = _res.nsaddr_list[0].sin_addr;
+    addr->type = V4;
+}
+
+static void push_question(Question** buf, Question q, uint8_t* amount, uint8_t* capacity) {
+    if (*amount >= *capacity) {
+        *capacity *= 2;
+        *buf = realloc(*buf, sizeof(Question) * *capacity);
+    }
+    (*buf)[*amount] = q;
+    (*amount)++;
+}
+
+void resolve_questions(int argc, char** argv, uint8_t* len, Question** questions) {
+    assert(argc > 0);
+
+    uint8_t amount = 0;
+    uint8_t capacity = 1;
+    Question* buf = malloc(sizeof(Question) * capacity);
+
+    Question q;
+    RecordType t;
+    if (argc == 1 && str_to_qtype(argv[0], &t)) {
+        create_question("", NS, &q);
+        push_question(&buf, q, &amount, &capacity);
+        *questions = buf;
+        *len = 1;
+        return;
+    }
+
+    for (int i = 0; i < argc; i++) {
+        if (str_to_qtype(argv[i], &t)) {
+            if (i + 1 == argc) break;
+            create_question(argv[i+1], t, &q);
+            i++;
+        } else if (i + 1 < argc && str_to_qtype(argv[i+1], &t)){
+            create_question(argv[i], t, &q); 
+            i++;
+        } else {
+            create_question(argv[i], A, &q);
+        }
+        push_question(&buf, q, &amount, &capacity);
+    }
+
+    *questions = buf;
+    *len = amount;
+}
+
+static void print_result(Packet* packet, const char* type, uint32_t ms) {
+    printf(">> Recieved response\n");
+    printf("Id: %hu, Code: %s\n", 
+        packet->header.id,
+        str_from_code(packet->header.rescode)
+    );
+    printf("Questions: %hu, Answers: %hu, Authorities: %hu, Resources: %hu\n",
+        packet->header.questions,
+        packet->header.answers,
+        packet->header.authoritative_entries,
+        packet->header.resource_entries
+    );
+    
+    if (packet->header.questions > 0) {
+        printf("\n>> Question Section\n");
+        for (uint16_t i = 0; i < packet->header.questions; i++) {
+            print_question(&packet->questions[i]);
+        }
+    }
+
+    if (packet->header.answers > 0) {
+        printf("\n>> Answer Section\n");
+        for (uint16_t i = 0; i < packet->header.answers; i++) {
+            print_record(&packet->answers[i]);
+        }
+    }  
+
+    if (packet->header.authoritative_entries > 0) {
+        printf("\n>> Authority Section\n");
+        for (uint16_t i = 0; i < packet->header.authoritative_entries; i++) {
+            print_record(&packet->authorities[i]);
+        }
+    }  
+
+    if (packet->header.resource_entries > 0) {
+        printf("\n>> Resource Section\n");
+        for (uint16_t i = 0; i < packet->header.resource_entries; i++) {
+            print_record(&packet->resources[i]);
+        }
+    }
+
+    printf("\n>> Query time: %ums (%s)\n", ms, type);
+}
+
+void resolve(IpAddr server, Options options, Question* questions, uint8_t len) {
+    struct timeval stop, start;
+    gettimeofday(&start, NULL);
+
+    SocketAddr addr;
+    create_socket_addr(options.port, server, &addr); 
+
+    Packet req;
+    memset(&req, 0, sizeof(Packet));
+    srand(time(NULL));
+    req.header.id = rand() % 65536;
+    req.header.questions = len;
+    req.header.recursion_desired = true;
+    req.questions = questions;
+
+    Connection conn;
+    if (options.force_tcp) goto tcp;
+
+    if (!create_request(UDP, &addr, &conn)) {
+        printf("error: failed to create udp request: %s\n", strerror(errno));
+        exit(EXIT_FAILURE);
+    }
+
+    Packet res;
+    if (!request_packet(&conn, &req, &res)) {
+        free_request(&conn);
+        free_packet(&req);
+        printf("error: failed to request udp packet: %s\n", strerror(errno));
+        exit(EXIT_FAILURE);
+    }
+
+    free_request(&conn);
+
+    if (!res.header.truncated_message) {
+        gettimeofday(&stop, NULL);
+        uint32_t ms = (stop.tv_sec - start.tv_sec) * 1000000 + stop.tv_usec - start.tv_usec;
+
+        print_result(&res, "UDP", ms / 1000);
+        free_packet(&req);
+        free_packet(&res);
+        return;
+    }
+
+    free_packet(&res);
+    printf("Response truncated, retrying in TCP...\n");
+    
+tcp:
+
+    if (!create_request(TCP, &addr, &conn)) {
+        printf("error: failed to create tcp request: %s\n", strerror(errno));
+        exit(EXIT_FAILURE);
+    }
+
+    if (!request_packet(&conn, &req, &res)) {
+        free_request(&conn);
+        printf("error: failed to request tcp packet: %s\n", strerror(errno));
+        exit(EXIT_FAILURE);
+    }
+
+    gettimeofday(&stop, NULL);
+    uint32_t ms = (stop.tv_sec - start.tv_sec) * 1000000 + stop.tv_usec - start.tv_usec;
+
+    print_result(&res, "TCP", ms / 1000);
+
+    free_request(&conn);
+    free_packet(&req);
+    free_packet(&res);
+}
+
diff --git a/src/client/client.h b/src/client/client.h
new file mode 100644
index 0000000..7e0e391
--- /dev/null
+++ b/src/client/client.h
@@ -0,0 +1,15 @@
+#pragma once
+
+#include "addr.h"
+#include "../packet/packet.h"
+
+typedef struct {
+    uint16_t port;
+    bool force_tcp;
+} Options;
+
+void resolve_default_server(IpAddr* addr);
+
+void resolve_questions(int argc, char** argv, uint8_t* len, Question** questions);
+
+void resolve(IpAddr server, Options options, Question* questions, uint8_t lem);
diff --git a/src/main.c b/src/main.c
new file mode 100644
index 0000000..454a8e8
--- /dev/null
+++ b/src/main.c
@@ -0,0 +1,112 @@
+#include "client/addr.h"
+#include "client/client.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/select.h>
+
+#define DEFAULT_PORT 53
+
+static void help() {
+    printf("wig: a simple dns client\n");
+    printf("usage: wig [@server] [options] domain [qtype]\n");
+    printf("arguments: \n");
+    printf("\t@server\t specify a dns server (@example.com)\n");
+    printf("\t-p\t specify a port (-p 2000)\n");
+    printf("\t-t\t force dns request to do tcp first\n");
+    exit(EXIT_SUCCESS);
+}
+
+static void parse_server (char* argv, char** server) {
+    if (*server != NULL) {
+        printf("error: only one dns server argument is allowed\n");
+        exit(EXIT_FAILURE);
+    }
+    if (strlen(argv) < 1) {
+        printf("error: dns server argument cannot be empty\n");
+        exit(EXIT_FAILURE);
+    }
+    *server = argv;
+}
+
+static int parse_arguent (int argc, char** argv, Options* options) {
+    if (strlen(argv[0]) < 2) {
+        printf("error: expected option after -\n");
+        exit(EXIT_FAILURE);
+    }
+
+    if (strcmp(argv[0], "-p") == 0) {
+        if (argc < 2) {
+            printf("error: expected port after -p\n");
+            exit(EXIT_FAILURE);
+        }
+        if ((options->port = strtoul(argv[1], NULL, 10)) == 0) {
+            printf("error: %s is not a valid port\n", argv[1]);
+            exit(EXIT_FAILURE);
+        }
+        return 1;
+    } else if (strcmp(argv[0], "-t") == 0) {
+        options->force_tcp = true;
+        return 0;
+    } else if (
+        strcmp(argv[0], "-h") == 0 ||
+        strcmp(argv[0], "--help") == 0
+    ) {
+        help();
+    }
+
+    printf("error: unkown option %s\n", argv[0]);
+    exit(EXIT_FAILURE);
+}
+
+int main(int argc, char** argv) {
+
+    if (argc < 1) return EXIT_FAILURE;
+
+    int dargs = 1;
+   
+    char* server = NULL;
+    Options options;
+    options.port = DEFAULT_PORT;
+    options.force_tcp = false;
+    
+    for (int i = 1; i < argc; i++) {
+        char s = argv[i][0];
+        if (s == '@') {
+            dargs++;
+            parse_server(argv[i] + 1, &server);
+        } else if (s == '-') {
+            int o = parse_arguent(argc - i, &argv[i], &options);
+            dargs++;
+            dargs += o;
+            i += o;
+        } else {
+            break;
+        }
+    }
+
+    if (argc - dargs < 1) {
+        printf("usage: wig [@server] [options] domain [qtype]\n");
+        return EXIT_FAILURE;
+    }
+
+    IpAddr addr;
+
+    if (server != NULL) {
+        if (!ip_addr_name(server, &addr)) {
+            printf("error: %s is not a valid domain\n", server);
+            exit(EXIT_FAILURE);
+        } 
+    } else {
+        resolve_default_server(&addr);
+    }
+
+    Question* arr;
+    uint8_t len;
+
+    resolve_questions(argc - dargs, &argv[dargs], &len, &arr);
+    resolve(addr, options, arr, len);
+
+    return EXIT_SUCCESS;
+}
diff --git a/src/packet/buffer.c b/src/packet/buffer.c
new file mode 100644
index 0000000..2d9386d
--- /dev/null
+++ b/src/packet/buffer.c
@@ -0,0 +1,247 @@
+#include "buffer.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+struct PacketBuffer {
+    uint8_t* arr;
+    int capacity;
+    int index;
+    int size;
+};
+
+PacketBuffer* buffer_create(int capacity) {
+    PacketBuffer* buffer = malloc(sizeof(PacketBuffer));
+    buffer->arr = malloc(capacity);
+    memset(buffer->arr, 0, capacity);
+    buffer->capacity = capacity;
+    buffer->size = 0;
+    buffer->index = 0;
+    return buffer;
+}
+
+void buffer_free(PacketBuffer* buffer) {
+    free(buffer->arr);
+    free(buffer);
+}
+
+void buffer_seek(PacketBuffer* buffer, int index) {
+    buffer->index = index;
+}
+
+uint8_t buffer_read(PacketBuffer* buffer) {
+    if (buffer->index >= buffer->size) {
+        return 0;
+    }
+    uint8_t data = buffer->arr[buffer->index];
+    buffer->index++;
+    return data;
+}
+
+uint16_t buffer_read_short(PacketBuffer* buffer) {
+    return
+        (uint16_t) buffer_read(buffer) << 8 |
+        (uint16_t) buffer_read(buffer);
+}
+
+uint32_t buffer_read_int(PacketBuffer* buffer) {
+    return
+        (uint32_t) buffer_read(buffer) << 24 |
+        (uint32_t) buffer_read(buffer) << 16 |
+        (uint32_t) buffer_read(buffer) << 8 |
+        (uint32_t) buffer_read(buffer);
+}
+
+uint8_t buffer_get(PacketBuffer* buffer, int index) {
+    if (index >= buffer->size) {
+        return 0;
+    }
+    uint8_t data = buffer->arr[index];
+    return data;
+}
+
+uint8_t* buffer_get_range(PacketBuffer* buffer, int start, int len) {
+    uint8_t* arr = malloc(len);
+    for (int i = 0; i < len; i++) {
+        arr[i] = buffer_get(buffer, start + i);
+    }
+    return arr;
+}
+
+uint16_t buffer_get_size(PacketBuffer* buffer) {
+    return (uint16_t) buffer->size + 1;
+}
+
+static void write(uint8_t** buffer, uint8_t* size, uint8_t* capacity, uint8_t data) {
+    if (*size >= *capacity) {
+        if (*capacity >= 128) {
+            *capacity = 255;
+        } else {
+            *capacity *= 2;
+        }
+        *buffer = realloc(*buffer, *capacity); 
+    }
+    (*buffer)[*size] = data;
+    (*size)++; 
+}
+
+void buffer_read_qname(PacketBuffer* buffer, uint8_t** out) {
+    int index = buffer->index;
+    int jumped = 0;
+
+    int max_jumps = 5;
+    int jumps_performed = 0;
+
+    uint8_t length = 0;
+    uint8_t capacity = 8;
+    *out = malloc(capacity);
+    write(out, &length, &capacity, 0);
+
+    while(1) {
+        if (jumps_performed > max_jumps) {
+            break;
+        }
+
+        uint8_t len = buffer_get(buffer, index);
+
+        if ((len & 0xC0) == 0xC0) {
+            if (jumped == 0) {
+                buffer_seek(buffer, index + 2);
+            } 
+
+            uint16_t b2 = (uint16_t) buffer_get(buffer, index + 1);
+            uint16_t offset = ((((uint16_t) len) ^ 0xC0) << 8) | b2;
+            index = (int) offset;
+            jumped = 1;
+            jumps_performed++;
+            continue;         
+        }
+
+        index++;
+
+        if (len == 0) {
+            break;
+        }
+
+        if (length > 1) {
+            write(out, &length, &capacity, '.');
+        }
+
+        uint8_t* range = buffer_get_range(buffer, index, len);
+        for (uint8_t i = 0; i < len; i++) {
+            write(out, &length, &capacity, range[i]);
+        } 
+        free(range);
+
+        index += (int) len;
+    }
+
+    if (jumped == 0) {
+        buffer_seek(buffer, index);
+    }
+    
+    (*out)[0] = length - 1;
+}
+
+void buffer_read_string(PacketBuffer* buffer, uint8_t** out) {
+    uint8_t len = buffer_read(buffer);
+    buffer_read_n(buffer, out, len);
+}
+
+static void buffer_expand(PacketBuffer* buffer, int capacity) {
+    if (buffer->capacity >= capacity) return;
+
+    buffer->arr = realloc(buffer->arr, capacity);
+    memset(buffer->arr + buffer->capacity, 0, capacity - buffer->capacity);
+    buffer->capacity = capacity;
+}
+
+void buffer_read_n(PacketBuffer* buffer, uint8_t** out, uint8_t len) {
+    buffer_expand(buffer, buffer->index + len + 1);
+    *out = malloc(len + 1);
+    *out[0] = len;
+    memcpy(*out + 1, buffer->arr + buffer->index, len);
+    buffer->index += len;
+}
+
+void buffer_write(PacketBuffer* buffer, uint8_t data) {
+    buffer_expand(buffer, buffer->index);
+    if (buffer->size < buffer->index + 1) {
+        buffer->size = buffer->index + 1;
+    }
+    buffer->arr[buffer->index] = data;
+    buffer->index++;
+}
+
+void buffer_write_short(PacketBuffer* buffer, uint16_t data) {
+    buffer_write(buffer, (uint8_t)(data >> 8));
+    buffer_write(buffer, (uint8_t)(data & 0xFF));
+}
+
+void buffer_write_int(PacketBuffer* buffer, uint32_t data) {
+    buffer_write(buffer, (uint8_t)(data >> 24));
+    buffer_write(buffer, (uint8_t)(data >> 16));
+    buffer_write(buffer, (uint8_t)(data >> 8));
+    buffer_write(buffer, (uint8_t)(data & 0xFF));
+}
+
+void buffer_write_qname(PacketBuffer* buffer, uint8_t* in) {
+    uint8_t part = 0;
+    uint8_t len = in[0];
+    
+    buffer_write(buffer, 0);
+    
+    if (len == 0) {
+        return;
+    }    
+
+    for(uint8_t i = 0; i < len; i ++) {
+        if (in[i+1] == '.') {
+            buffer_set(buffer, part, buffer->index - (int)part - 1);
+            buffer_write(buffer, 0);
+            part = 0;
+        } else {
+            buffer_write(buffer, in[i+1]);
+            part++;
+        }
+    }
+    buffer_set(buffer, part, buffer->index - (int)part - 1);
+    buffer_write(buffer, 0);
+}
+
+void buffer_write_string(PacketBuffer* buffer, uint8_t* in) {
+    buffer_write(buffer, in[0]);
+    buffer_write_n(buffer, in + 1, in[0]);
+}
+
+void buffer_write_n(PacketBuffer* buffer, uint8_t* in, int len) {
+    buffer_expand(buffer, buffer->size + len);
+    memcpy(buffer->arr + buffer->index, in, len);
+    buffer->size += len;
+    buffer->index += len;
+}
+
+void buffer_set(PacketBuffer* buffer, uint8_t data, int index) {
+    if (index > buffer->size) {
+        return;
+    }
+    buffer->arr[index] = data;
+}
+
+void buffer_set_uint16_t(PacketBuffer* buffer, uint16_t data, int index) {
+    buffer_set(buffer, (uint8_t)(data >> 8), index);
+    buffer_set(buffer, (uint8_t)(data & 0xFF), index + 1);
+}
+
+int buffer_get_index(PacketBuffer* buffer) {
+    return buffer->index;
+}
+
+void buffer_step(PacketBuffer* buffer, int len) {
+    buffer->index += len;
+}
+
+uint8_t* buffer_get_ptr(PacketBuffer* buffer) {
+    return buffer->arr;
+}
diff --git a/src/packet/buffer.h b/src/packet/buffer.h
new file mode 100644
index 0000000..ad3145d
--- /dev/null
+++ b/src/packet/buffer.h
@@ -0,0 +1,51 @@
+#pragma once
+
+#include <stdint.h>
+
+typedef struct PacketBuffer PacketBuffer;
+
+PacketBuffer* buffer_create(int capacity);
+
+void buffer_free(PacketBuffer* buffer);
+
+void buffer_seek(PacketBuffer* buffer, int index);
+
+uint8_t buffer_read(PacketBuffer* buffer);
+
+uint16_t buffer_read_short(PacketBuffer* buffer);
+
+uint32_t buffer_read_int(PacketBuffer* buffer);
+
+uint8_t buffer_get(PacketBuffer* buffer, int index);
+
+uint8_t* buffer_get_range(PacketBuffer* buffer, int start, int len);
+
+uint16_t buffer_get_size(PacketBuffer* buffer);
+
+void buffer_read_qname(PacketBuffer* buffer, uint8_t** out);
+
+void buffer_read_string(PacketBuffer* buffer, uint8_t** out);
+
+void buffer_read_n(PacketBuffer* buffer, uint8_t** out, uint8_t len);
+
+void buffer_write(PacketBuffer* buffer, uint8_t data);
+
+void buffer_write_short(PacketBuffer* buffer, uint16_t data);
+
+void buffer_write_int(PacketBuffer* buffer, uint32_t data);
+
+void buffer_write_qname(PacketBuffer* buffer, uint8_t* in);
+
+void buffer_write_string(PacketBuffer* buffer, uint8_t* in);
+
+void buffer_write_n(PacketBuffer* buffer, uint8_t* in, int len);
+
+void buffer_set(PacketBuffer* buffer, uint8_t data, int index);
+
+void buffer_set_uint16_t(PacketBuffer* buffer, uint16_t data, int index);
+
+int buffer_get_index(PacketBuffer* buffer);
+
+void buffer_step(PacketBuffer* buffer, int len);
+
+uint8_t* buffer_get_ptr(PacketBuffer* buffer);
diff --git a/src/packet/header.c b/src/packet/header.c
new file mode 100644
index 0000000..b74ebb1
--- /dev/null
+++ b/src/packet/header.c
@@ -0,0 +1,108 @@
+#include "header.h"
+#include "buffer.h"
+
+#include <netinet/in.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <arpa/inet.h>
+
+uint8_t rescode_to_id(ResultCode code) {
+    switch(code) {
+        case NOERROR:
+            return 0;
+        case FORMERR:
+            return 1;
+        case SERVFAIL:
+            return 2;
+        case NXDOMAIN:
+            return 3;
+        case NOTIMP:
+            return 4;
+        case REFUSED:
+            return 5;
+        default:
+            return 2;
+    }
+}
+
+ResultCode rescode_from_id(uint8_t id) {
+    switch(id) {
+        case 0:
+            return NOERROR;
+        case 1:
+            return FORMERR;
+        case 2:
+            return SERVFAIL;
+        case 3:
+            return NXDOMAIN;
+        case 4:
+            return NOTIMP;
+        case 5:
+            return REFUSED;
+        default:
+            return FORMERR;
+    }
+}
+
+const char* str_from_code(ResultCode code) {
+    switch(code) {
+        case NOERROR: return "NOERROR";
+        case FORMERR: return "FORMERR";
+        case SERVFAIL: return "SERVFAIL";
+        case NXDOMAIN: return "NXDOMAIN";
+        case NOTIMP: return "NOTIMP";
+        case REFUSED: return "REFUSED";
+        default: return "????";
+    }
+}
+
+#define MAX(var, max) var = var > max ? max : var;
+
+void read_header(PacketBuffer* buffer, Header* header) {
+    // memset(header, 0, sizeof(Header));
+    header->id = buffer_read_short(buffer);
+
+    uint8_t a = buffer_read(buffer);
+    header->recursion_desired = (a & (1 << 0)) > 0;
+    header->truncated_message = (a & (1 << 1)) > 0;
+    header->authorative_answer = (a & (1 << 2)) > 0;
+    header->opcode = (a >> 3) & 0x0F;
+    header->response = (a & (1 << 7)) > 0;
+
+    uint8_t b = buffer_read(buffer);
+    header->rescode = rescode_from_id(b & 0x0F);
+    header->checking_disabled = (b & (1 << 4)) > 0;
+    header->authed_data = (b& (1 << 4)) > 0;
+    header->z = (b & (1 << 6)) > 0;
+    header->recursion_available = (b & (1 << 7)) > 0;
+    header->questions = buffer_read_short(buffer);
+    header->answers = buffer_read_short(buffer);
+    header->authoritative_entries = buffer_read_short(buffer);
+    header->resource_entries = buffer_read_short(buffer);
+}
+
+void write_header(PacketBuffer* buffer, Header* header) {
+    buffer_write_short(buffer, header->id);
+
+    buffer_write(buffer,
+        ((uint8_t) header->recursion_desired) |
+        ((uint8_t) header->truncated_message << 1) |
+        ((uint8_t) header->authorative_answer << 2) |
+        (header->opcode << 3) |
+        ((uint8_t) header->response << 7) 
+    );
+
+    buffer_write(buffer, 
+        (rescode_to_id(header->rescode)) |
+        ((uint8_t) header->checking_disabled << 4) |
+        ((uint8_t) header->authed_data << 5) |
+        ((uint8_t) header->z << 6) |
+        ((uint8_t) header->recursion_available << 7) 
+    );
+
+    buffer_write_short(buffer, header->questions);
+    buffer_write_short(buffer, header->answers);
+    buffer_write_short(buffer, header->authoritative_entries);
+    buffer_write_short(buffer, header->resource_entries);
+}
diff --git a/src/packet/header.h b/src/packet/header.h
new file mode 100644
index 0000000..a824ec3
--- /dev/null
+++ b/src/packet/header.h
@@ -0,0 +1,42 @@
+#pragma once
+
+#include "buffer.h"
+
+#include <stdbool.h>
+
+typedef enum {
+    NOERROR,    // 0
+    FORMERR,    // 1
+    SERVFAIL,   // 2
+    NXDOMAIN,   // 3,
+    NOTIMP,     // 4
+    REFUSED,    // 5
+} ResultCode;
+
+uint8_t rescode_to_id(ResultCode code);
+ResultCode rescode_from_id(uint8_t id);
+
+typedef struct {
+    uint16_t id;
+
+    bool recursion_desired;     // 1 bit
+    bool truncated_message;     // 1 bit
+    bool authorative_answer;    // 1 bit
+    uint8_t opcode;               // 4 bits
+    bool response;              // 1 bit
+
+    ResultCode rescode;         // 4 bits
+    bool checking_disabled;     // 1 bit
+    bool authed_data;           // 1 bit
+    bool z;                     // 1 bit
+    bool recursion_available;   // 1 bit
+
+    uint16_t questions;               // 16 bits
+    uint16_t answers;                 // 16 bits
+    uint16_t authoritative_entries;   // 16 bits
+    uint16_t resource_entries;        // 16 bits
+} Header;
+
+void read_header(PacketBuffer* buffer, Header* header);
+void write_header(PacketBuffer* buffer, Header* header);
+const char* str_from_code(ResultCode code);
diff --git a/src/packet/packet.c b/src/packet/packet.c
new file mode 100644
index 0000000..83dc5c3
--- /dev/null
+++ b/src/packet/packet.c
@@ -0,0 +1,184 @@
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include "packet.h"
+#include "buffer.h"
+#include "header.h"
+#include "question.h"
+#include "record.h"
+
+void read_packet(PacketBuffer* buffer, Packet* packet) {
+    read_header(buffer, &packet->header);
+    
+    packet->questions = malloc(sizeof(Question) * packet->header.questions);
+    for(uint16_t i = 0; i < packet->header.questions; i++) {
+        if (!read_question(buffer, &packet->questions[i])) {
+            i--;
+            packet->header.questions--;
+        }
+    }
+
+    packet->answers = malloc(sizeof(Record) * packet->header.answers);
+    for(uint16_t i = 0; i < packet->header.answers; i++) {
+        if (!read_record(buffer, &packet->answers[i])) {
+            i--;
+            packet->header.answers--;
+        }
+    }
+
+    packet->authorities = malloc(sizeof(Record) * packet->header.authoritative_entries);
+    for(uint16_t i = 0; i < packet->header.authoritative_entries; i++) {
+        if (!read_record(buffer, &packet->authorities[i])) {
+            i--;
+            packet->header.authoritative_entries--;
+        }
+    }
+
+    packet->resources = malloc(sizeof(Record) * packet->header.resource_entries);
+    for(uint16_t i = 0; i < packet->header.resource_entries; i++) {
+        if (!read_record(buffer, &packet->resources[i])) {
+            i--;
+            packet->header.resource_entries--;
+        }
+    }
+}
+
+void write_packet(PacketBuffer* buffer, Packet* packet) {
+    write_header(buffer, &packet->header);
+    
+    for(uint16_t i = 0; i < packet->header.questions; i++) {
+        write_question(buffer, &packet->questions[i]);
+    }
+
+    for(uint16_t i = 0; i < packet->header.answers; i++) {
+        write_record(buffer, &packet->answers[i]);
+    }
+
+    for(uint16_t i = 0; i < packet->header.authoritative_entries; i++) {
+        write_record(buffer, &packet->authorities[i]);
+    }
+
+    for(uint16_t i = 0; i < packet->header.resource_entries; i++) {
+        write_record(buffer, &packet->resources[i]);
+    }
+}
+
+void free_packet(Packet* packet) {
+    
+    for(uint16_t i = 0; i < packet->header.questions; i++) {
+        free_question(&packet->questions[i]);
+    }
+    free(packet->questions);
+
+    for(uint16_t i = 0; i < packet->header.answers; i++) {
+        free_record(&packet->answers[i]);
+    }
+    free(packet->answers);
+
+    for(uint16_t i = 0; i < packet->header.authoritative_entries; i++) {
+        free_record(&packet->authorities[i]);
+    }
+    free(packet->authorities);
+
+    for(uint16_t i = 0; i < packet->header.resource_entries; i++) {
+        free_record(&packet->resources[i]);
+    }
+    free(packet->resources);
+}
+
+bool get_random_a(Packet* packet, IpAddr* addr) {
+    for (uint16_t i = 0; i < packet->header.answers; i++) {
+        Record record = packet->answers[i];
+        if (record.type == A) {
+            create_ip_addr(record.data.a.addr, addr);
+            return true;
+        } else if (record.type == AAAA) {
+            create_ip_addr6(record.data.aaaa.addr, addr);
+            return true;
+        }
+    }
+    return false;
+}
+
+static bool ends_with(uint8_t* full, uint8_t* end) {
+    uint8_t check = end[0];
+    uint8_t len = full[0];
+
+    if (check > len) {
+        return false;
+    }
+
+    for(uint8_t i = 0; i < check; i++) {
+        if (end[check - 1 - i] != full[len - 1 - i]) {
+            return false;
+        }
+    }
+    
+    return true;
+}
+
+static bool equals(uint8_t* a, uint8_t* b) {
+    if (a[0] != b[0]) {
+        return false;
+    }
+
+    for(uint8_t i = 1; i < a[0] + 1; i++) {
+        if(a[i] != b[i]) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+bool get_resolved_ns(Packet* packet, uint8_t* qname, IpAddr* addr) {
+    for (uint16_t i = 0; i < packet->header.authoritative_entries; i++) {
+        Record record = packet->authorities[i];
+        if (record.type != NS) {
+            continue;
+        }
+
+        if(!ends_with(qname, record.domain)) {
+            continue;
+        }
+
+        for (uint16_t i = 0; i < packet->header.resource_entries; i++) {
+            Record resource = packet->resources[i];
+            if (!equals(record.data.ns.host, resource.domain)) {
+                continue;
+            }
+
+            if (resource.type == A) {
+                create_ip_addr(record.data.a.addr, addr);
+                return true;
+            } else if (resource.type == AAAA) {
+                create_ip_addr6(record.data.aaaa.addr, addr);
+                return true;
+            }
+        }
+    }
+    return false;
+}
+
+bool get_unresoled_ns(Packet* packet, uint8_t* qname, Question* question) {
+    for (uint16_t i = 0; i < packet->header.authoritative_entries; i++) {
+        Record record = packet->authorities[i];
+        if (record.type != NS) {
+            continue;
+        }
+
+        if(!ends_with(qname, record.domain)) {
+            continue;
+        }
+
+        uint8_t* host = record.data.ns.host;
+
+        question->qtype = NS;
+        question->domain = malloc(host[0] + 1);
+        memcpy(question->domain, host, host[0] + 1);
+        return true;
+    }
+    return false;
+}
diff --git a/src/packet/packet.h b/src/packet/packet.h
new file mode 100644
index 0000000..12845b9
--- /dev/null
+++ b/src/packet/packet.h
@@ -0,0 +1,25 @@
+#pragma once
+
+#include "buffer.h"
+#include "question.h"
+#include "header.h"
+#include "record.h"
+#include "../client/addr.h"
+
+#include <stdbool.h>
+
+typedef struct {
+    Header header;
+    Question* questions;
+    Record* answers;
+    Record* authorities;
+    Record* resources;
+} Packet;
+
+void read_packet(PacketBuffer* buffer, Packet* packet);
+void write_packet(PacketBuffer* buffer, Packet* packet);
+void free_packet(Packet* packet);
+
+bool get_random_a(Packet* packet, IpAddr* addr);
+bool get_resolved_ns(Packet* packet, uint8_t* qname, IpAddr* addr);
+bool get_unresoled_ns(Packet* packet, uint8_t* qname, Question* question);
diff --git a/src/packet/question.c b/src/packet/question.c
new file mode 100644
index 0000000..8159a07
--- /dev/null
+++ b/src/packet/question.c
@@ -0,0 +1,79 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+
+#include "question.h"
+#include "buffer.h"
+#include "record.h"
+
+void create_question(const char* domain, RecordType qtype, Question* question) {
+    uint8_t len = strlen(domain);
+    question->domain = malloc(len + 1);
+    question->qtype = qtype;
+    question->domain[0] = len;
+    question->cls = 1;
+    memcpy(question->domain + 1, domain, len);
+}
+
+bool read_question(PacketBuffer* buffer, Question* question) {
+    buffer_read_qname(buffer, &question->domain);
+    
+    uint16_t qtype_num = buffer_read_short(buffer);
+    record_from_id(qtype_num, &question->qtype);
+    question->cls = buffer_read_short(buffer);
+
+    if (question->qtype == UNKOWN) {
+        free(question->domain);
+        return false;
+    }
+
+    return true;
+}
+
+void write_question(PacketBuffer* buffer, Question* question) {
+    buffer_write_qname(buffer, question->domain);
+    
+    uint16_t id = record_to_id(question->qtype);
+    buffer_write_short(buffer, id);
+
+    buffer_write_short(buffer, question->cls);
+}
+
+void free_question(Question* question) {
+    free(question->domain);
+}
+
+static const char* class_to_str(Question* question) {
+    switch(question->cls) {
+        case 1: return "IN";
+        case 3: return "CH";
+        case 4: return "HS";
+        default: return "??";
+    }
+}
+
+static const char* qtype_to_str(Question* question) {
+    switch(question->qtype) {
+        case A: return "A";
+        case NS: return "NS";
+        case CNAME: return "CNAME";
+        case SOA: return "SOA";
+        case PTR: return "PTR";
+        case MX: return "MX";
+        case TXT: return "TXT";
+        case AAAA: return "AAAA";
+        case SRV: return "SRV";
+        case CAA: return "CAA";
+        default: return "UNKOWN";
+    }
+}
+
+void print_question(Question* question) {
+    printf("%.*s.\t%s %s\n",
+        question->domain[0],
+        question->domain + 1,
+        class_to_str(question),
+        qtype_to_str(question)
+    );
+}
diff --git a/src/packet/question.h b/src/packet/question.h
new file mode 100644
index 0000000..9f5dde7
--- /dev/null
+++ b/src/packet/question.h
@@ -0,0 +1,16 @@
+#pragma once
+
+#include "buffer.h"
+#include "record.h"
+
+typedef struct {
+    uint8_t* domain;
+    RecordType qtype;
+    uint16_t cls;
+} Question;
+
+void create_question(const char* domain, RecordType qtype, Question* question);
+bool read_question(PacketBuffer* buffer, Question* question);
+void write_question(PacketBuffer* buffer, Question* question);
+void free_question(Question* question);
+void print_question(Question* question);
diff --git a/src/packet/record.c b/src/packet/record.c
new file mode 100644
index 0000000..ba3186a
--- /dev/null
+++ b/src/packet/record.c
@@ -0,0 +1,608 @@
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#undef _POSIX_C_SOURCE
+#include <stdio.h>
+
+#include "record.h"
+#include "buffer.h"
+
+uint16_t record_to_id(RecordType type) {
+    switch (type) {
+        case A:
+            return 1;
+        case NS:
+            return 2;
+        case CNAME:
+            return 5;
+        case SOA:
+            return 6;
+        case PTR:
+            return 12;
+        case MX:
+            return 15;
+        case TXT:
+            return 16;
+        case AAAA:
+            return 28;
+        case SRV:
+            return 33;
+        case CAA:
+            return 257;
+        default:
+            return 0;
+    }
+}
+
+void record_from_id(uint16_t i, RecordType* type) {
+    switch (i) {
+        case 1:
+            *type = A;
+            break;
+        case 2:
+            *type = NS;
+            break;
+        case 5:
+            *type = CNAME;
+            break;
+        case 6:
+            *type = SOA;
+            break;
+        case 12:
+            *type = PTR;
+            break;
+        case 15:
+            *type = MX;
+            break;
+        case 16:
+            *type = TXT;
+            break;
+        case 28:
+            *type = AAAA;
+            break;
+        case 33:
+            *type = SRV;
+            break;
+        case 257:
+            *type = CAA;
+            break;
+        default:
+            *type = UNKOWN;
+    }
+}
+
+bool str_to_qtype(const char* qstr, RecordType* qtype) {
+    if (strcasecmp(qstr, "A") == 0) {
+        *qtype = A;
+        return true;
+    } else if (strcasecmp(qstr, "NS") == 0) {
+        *qtype = NS;
+        return true;
+    } else if (strcasecmp(qstr, "CNAME") == 0) {
+        *qtype = CNAME;
+        return true;
+    } else if (strcasecmp(qstr, "SOA") == 0) {
+        *qtype = SOA;
+        return true;
+    } else if (strcasecmp(qstr, "PTR") == 0) {
+        *qtype = PTR;
+        return true;
+    } else if (strcasecmp(qstr, "MX") == 0) {
+        *qtype = MX;
+        return true;
+    } else if (strcasecmp(qstr, "TXT") == 0) {
+        *qtype = TXT;
+        return true;
+    } else if (strcasecmp(qstr, "AAAA") == 0) {
+        *qtype = AAAA;
+        return true;
+    } else if (strcasecmp(qstr, "SRV") == 0) {
+        *qtype = SRV;
+        return true;
+    } else if (strcasecmp(qstr, "CAA") == 0) {
+        *qtype = CAA;
+        return true;
+    } else { 
+        return false;
+    }
+    return false;
+}
+
+static void read_a_record(PacketBuffer* buffer, Record* record) {
+    ARecord data;
+    data.addr[0] = buffer_read(buffer);
+    data.addr[1] = buffer_read(buffer);
+    data.addr[2] = buffer_read(buffer);
+    data.addr[3] = buffer_read(buffer);
+
+    record->data.a = data;
+}
+
+static void read_ns_record(PacketBuffer* buffer, Record* record) {
+    NSRecord data;
+    buffer_read_qname(buffer, &data.host);
+
+    record->data.ns = data;
+}
+
+static void read_cname_record(PacketBuffer* buffer, Record* record) {
+    CNAMERecord data;
+    buffer_read_qname(buffer, &data.host);
+
+    record->data.cname = data;
+}
+
+static void read_soa_record(PacketBuffer* buffer, Record* record) {
+    SOARecord data;
+    buffer_read_qname(buffer, &data.mname);
+    buffer_read_qname(buffer, &data.nname);
+    data.serial = buffer_read_int(buffer);
+    data.refresh = buffer_read_int(buffer);
+    data.retry = buffer_read_int(buffer);
+    data.expire = buffer_read_int(buffer);
+    data.minimum = buffer_read_int(buffer);
+
+    record->data.soa = data;
+}
+
+static void read_ptr_record(PacketBuffer* buffer, Record* record) {
+    PTRRecord data;
+    buffer_read_qname(buffer, &data.pointer);
+
+    record->data.ptr = data;
+}
+
+static void read_mx_record(PacketBuffer* buffer, Record* record) {
+    MXRecord data;
+    data.priority = buffer_read_short(buffer);
+    buffer_read_qname(buffer, &data.host);
+
+    record->data.mx = data;
+}
+
+static void read_txt_record(PacketBuffer* buffer, Record* record) {
+    TXTRecord data;
+    data.len = 0;
+    data.text = malloc(sizeof(uint8_t*) * 2);
+    uint8_t capacity = 2;
+    uint8_t total = record->len;
+    while (1) {
+        if (data.len >= capacity) {
+            if (capacity >= 128) {
+                capacity = 255;
+            } else {
+                capacity *= 2;
+            }
+            data.text = realloc(data.text, sizeof(uint8_t*) * capacity);
+        }
+
+        buffer_read_string(buffer, &data.text[data.len]);
+        if(data.text[data.len][0] == 0) {
+            free(data.text[data.len]);
+            break;
+        }
+
+        data.len++;
+
+        total -= data.text[data.len - 1][0] + 1;
+        if (total == 0) break;
+    }
+
+    record->data.txt = data;
+}
+
+static void read_aaaa_record(PacketBuffer* buffer, Record* record) {
+    AAAARecord data;
+    for (int i = 0; i < 16; i++) {
+        data.addr[i] = buffer_read(buffer);
+    }
+
+    record->data.aaaa = data;
+}
+
+static void read_srv_record(PacketBuffer* buffer, Record* record) {
+    SRVRecord data;
+    data.priority = buffer_read_short(buffer);
+    data.weight = buffer_read_short(buffer);
+    data.port = buffer_read_short(buffer);
+    buffer_read_qname(buffer, &data.target);
+
+    record->data.srv = data;
+}
+
+static void read_caa_record(PacketBuffer* buffer, Record* record, int header_pos) {
+    CAARecord data;
+    data.flags = buffer_read(buffer);
+    data.length = buffer_read(buffer);
+    buffer_read_n(buffer, &data.tag, data.length);
+    int value_len = ((int)record->len) + header_pos - buffer_get_index(buffer);
+    buffer_read_n(buffer, &data.value, (uint8_t)value_len);
+
+    record->data.caa = data;
+}
+
+bool read_record(PacketBuffer* buffer, Record* record) {
+    buffer_read_qname(buffer, &record->domain);
+
+    uint16_t qtype_num = buffer_read_short(buffer);
+    record_from_id(qtype_num, &record->type);
+
+    record->cls = buffer_read_short(buffer);
+    record->ttl = buffer_read_int(buffer);
+    record->len = buffer_read_short(buffer);
+
+    int header_pos = buffer_get_index(buffer);
+
+    switch (record->type) {
+        case A:
+            read_a_record(buffer, record);
+            break;
+        case NS:
+            read_ns_record(buffer, record);
+            break;
+        case CNAME:
+            read_cname_record(buffer, record);
+            break;
+        case SOA:
+            read_soa_record(buffer, record);
+            break;
+        case PTR:
+            read_ptr_record(buffer, record);
+            break;
+        case MX:
+            read_mx_record(buffer, record);
+            break;
+        case TXT:
+            read_txt_record(buffer, record);
+            break;
+        case AAAA:
+            read_aaaa_record(buffer, record);
+            break;
+        case SRV:
+            read_srv_record(buffer, record);
+            break;
+        case CAA:
+            read_caa_record(buffer, record, header_pos);
+            break;
+        default:
+            buffer_step(buffer, record->len);
+            free(record->domain);
+            return false;
+    }
+
+    return true;
+}
+
+static void write_a_record(PacketBuffer* buffer, ARecord* data) {
+    buffer_write_short(buffer, 4);
+    buffer_write(buffer, data->addr[0]);
+    buffer_write(buffer, data->addr[1]);
+    buffer_write(buffer, data->addr[2]);
+    buffer_write(buffer, data->addr[3]);
+}
+
+static void write_ns_record(PacketBuffer* buffer, NSRecord* data) {
+    int pos = buffer_get_index(buffer);
+    buffer_write_short(buffer, 0);
+
+    buffer_write_qname(buffer, data->host);
+
+    int size = buffer_get_index(buffer) - pos - 2;
+    buffer_set_uint16_t(buffer, (uint16_t)size, pos);
+}
+
+static void write_cname_record(PacketBuffer* buffer, CNAMERecord* data) {
+    int pos = buffer_get_index(buffer);
+    buffer_write_short(buffer, 0);
+
+    buffer_write_qname(buffer, data->host);
+
+    int size = buffer_get_index(buffer) - pos - 2;
+    buffer_set_uint16_t(buffer, (uint16_t)size, pos);
+}
+
+static void write_soa_record(PacketBuffer* buffer, SOARecord* data) {
+    int pos = buffer_get_index(buffer);
+    buffer_write_short(buffer, 0);
+
+    buffer_write_qname(buffer, data->mname);
+    buffer_write_qname(buffer, data->nname);
+    buffer_write_int(buffer, data->serial);
+    buffer_write_int(buffer, data->refresh);
+    buffer_write_int(buffer, data->retry);
+    buffer_write_int(buffer, data->expire);
+    buffer_write_int(buffer, data->minimum);
+
+    int size = buffer_get_index(buffer) - pos - 2;
+    buffer_set_uint16_t(buffer, (uint16_t)size, pos);
+}
+
+static void write_ptr_record(PacketBuffer* buffer, PTRRecord* data) {
+    int pos = buffer_get_index(buffer);
+    buffer_write_short(buffer, 0);
+
+    buffer_write_qname(buffer, data->pointer);
+
+    int size = buffer_get_index(buffer) - pos - 2;
+    buffer_set_uint16_t(buffer, (uint16_t)size, pos);
+}
+
+static void write_mx_record(PacketBuffer* buffer, MXRecord* data) {
+    int pos = buffer_get_index(buffer);
+    buffer_write_short(buffer, 0);
+
+    buffer_write_short(buffer, data->priority);
+    buffer_write_qname(buffer, data->host);
+
+    int size = buffer_get_index(buffer) - pos - 2;
+    buffer_set_uint16_t(buffer, (uint16_t)size, pos);
+}
+
+static void write_txt_record(PacketBuffer* buffer, TXTRecord* data) {
+    int pos = buffer_get_index(buffer);
+    buffer_write_short(buffer, 0);
+
+    if(data->len == 0) {
+        return;
+    }
+
+    for(uint8_t i = 0; i < data->len; i++) {
+        buffer_write_string(buffer, data->text[i]);
+    }
+
+    int size = buffer_get_index(buffer) - pos - 2;
+    buffer_set_uint16_t(buffer, (uint16_t)size, pos);
+}
+
+static void write_aaaa_record(PacketBuffer* buffer, AAAARecord* data) {
+    buffer_write_short(buffer, 16);
+
+    for (int i = 0; i < 16; i++) {
+        buffer_write(buffer, data->addr[i]);
+    }
+}
+
+static void write_srv_record(PacketBuffer* buffer, SRVRecord* data) {
+    int pos = buffer_get_index(buffer);
+    buffer_write_short(buffer, 0);
+
+    buffer_write_short(buffer, data->priority);
+    buffer_write_short(buffer, data->weight);
+    buffer_write_short(buffer, data->port);
+    buffer_write_qname(buffer, data->target);
+
+    int size = buffer_get_index(buffer) - pos - 2;
+    buffer_set_uint16_t(buffer, (uint16_t)size, pos);
+}
+
+static void write_caa_record(PacketBuffer* buffer, CAARecord* data) {
+    int pos = buffer_get_index(buffer);
+    buffer_write_short(buffer, 0);
+    buffer_write(buffer, data->flags);
+    buffer_write(buffer, data->length);
+    buffer_write_n(buffer, data->tag + 1, data->tag[0]);
+    buffer_write_n(buffer, data->value + 1, data->value[0]);
+
+    int size = buffer_get_index(buffer) - pos - 2;
+    buffer_set_uint16_t(buffer, (uint16_t)size, pos);
+}
+
+static void write_record_header(PacketBuffer* buffer, Record* record) {
+    buffer_write_qname(buffer, record->domain);
+    uint16_t id = record_to_id(record->type);
+    buffer_write_short(buffer, id);
+    buffer_write_short(buffer, record->cls);
+    buffer_write_int(buffer, record->ttl);
+}
+
+void write_record(PacketBuffer* buffer, Record* record) {
+    switch(record->type) {
+        case A:
+            write_record_header(buffer, record);
+            write_a_record(buffer, &record->data.a);
+            break; 
+        case NS:
+            write_record_header(buffer, record);
+            write_ns_record(buffer, &record->data.ns);
+            break;
+        case CNAME:
+            write_record_header(buffer, record);
+            write_cname_record(buffer, &record->data.cname);
+            break;
+        case SOA:
+            write_record_header(buffer, record);
+            write_soa_record(buffer, &record->data.soa);
+            break;
+        case PTR:
+            write_record_header(buffer, record);
+            write_ptr_record(buffer, &record->data.ptr);
+            break;
+        case MX:
+            write_record_header(buffer, record);
+            write_mx_record(buffer, &record->data.mx);
+            break;
+        case TXT:
+            write_record_header(buffer, record);
+            write_txt_record(buffer, &record->data.txt);
+            break;
+        case AAAA:
+            write_record_header(buffer, record);
+            write_aaaa_record(buffer, &record->data.aaaa);
+            break;
+        case SRV:
+            write_record_header(buffer, record);
+            write_srv_record(buffer, &record->data.srv);
+            break;
+        case CAA:
+            write_record_header(buffer, record);
+            write_caa_record(buffer, &record->data.caa);
+            break;
+        default:
+            break;
+    }
+
+}
+
+void free_record(Record* record) {
+    free(record->domain);
+    switch (record->type) {
+        case NS:
+            free(record->data.ns.host);
+            break;
+        case CNAME:
+            free(record->data.cname.host);
+            break;
+        case SOA:
+            free(record->data.soa.mname);
+            free(record->data.soa.nname);
+            break;
+        case PTR:
+            free(record->data.ptr.pointer);
+            break;
+        case MX:
+            free(record->data.mx.host);
+            break;
+        case TXT:
+            for (uint8_t i = 0; i < record->data.txt.len; i++) {
+                free(record->data.txt.text[i]);
+            }
+            free(record->data.txt.text);
+            break;
+        case SRV:
+            free(record->data.srv.target);
+            break;
+        case CAA:
+            free(record->data.caa.value);
+            free(record->data.caa.tag);
+            break;
+        default:
+            break;
+        }
+}
+
+static const char* class_to_str(Record* record) {
+    switch(record->cls) {
+        case 1: return "IN";
+        case 3: return "CH";
+        case 4: return "HS";
+        default: return "??";
+    }
+}
+
+static const char* qtype_to_str(Record* record) {
+    switch(record->type) {
+        case A: return "A";
+        case NS: return "NS";
+        case CNAME: return "CNAME";
+        case SOA: return "SOA";
+        case PTR: return "PTR";
+        case MX: return "MX";
+        case TXT: return "TXT";
+        case AAAA: return "AAAA";
+        case SRV: return "SRV";
+        case CAA: return "CAA";
+        default: return "UNKOWN";
+    }
+}
+
+static void print_record_data(Record* record) {
+    switch(record->type) {
+        case A:
+            printf("%hhu.%hhu.%hhu.%hhu",
+                record->data.a.addr[0],
+                record->data.a.addr[1],
+                record->data.a.addr[2],
+                record->data.a.addr[3]
+            );
+            break;
+        case NS:
+            printf("%.*s",
+                record->data.ns.host[0],
+                record->data.ns.host + 1
+            );
+            break;
+        case CNAME:
+            printf("%.*s",
+                record->data.cname.host[0],
+                record->data.cname.host + 1
+            );
+            break;
+        case SOA:
+            printf("%.*s %.*s %u %u %u %u %u",
+                record->data.soa.mname[0],
+                record->data.soa.mname + 1,
+                record->data.soa.nname[0],
+                record->data.soa.nname + 1,
+                record->data.soa.serial,
+                record->data.soa.refresh,
+                record->data.soa.retry,
+                record->data.soa.expire,
+                record->data.soa.minimum
+            );
+            break;
+        case PTR:
+            printf("%.*s",
+                record->data.ptr.pointer[0],
+                record->data.ptr.pointer + 1
+            );
+            break;
+        case MX:
+            printf("%.*s %hu",
+                record->data.mx.host[0],
+                record->data.mx.host + 1,
+                record->data.mx.priority
+            );
+            break;
+        case TXT:
+            for(uint8_t i = 0; i < record->data.txt.len; i++) {
+                printf("%.*s",
+                    record->data.txt.text[i][0],
+                    record->data.txt.text[i] + 1
+                );
+            }
+            break;
+        case AAAA:
+            for(int i = 0; i < 8; i++) {
+                printf("%02hhx%02hhx:",
+                    record->data.a.addr[i*2 + 0],
+                    record->data.a.addr[i*2 + 1]
+                );
+            }
+            printf(":");
+            break;
+        case SRV:
+            printf("SRV (%hu %hu %hu %.*s",
+                record->data.srv.priority,
+                record->data.srv.weight,
+                record->data.srv.port,
+                record->data.srv.target[0],
+                record->data.srv.target + 1
+            );
+            break;
+        case CAA:
+            printf("%hhu %.*s %.*s",
+                record->data.caa.flags,
+                record->data.caa.tag[0],
+                record->data.caa.tag + 1,
+                record->data.caa.value[0],
+                record->data.caa.value + 1
+            );
+            break;
+        default:
+            break;
+    } 
+}
+
+void print_record(Record* record) {
+    printf("%.*s.\t%s %s\t",
+        record->domain[0],
+        record->domain + 1,
+        class_to_str(record),
+        qtype_to_str(record)
+    );
+    print_record_data(record);
+    printf("\n");
+}
diff --git a/src/packet/record.h b/src/packet/record.h
new file mode 100644
index 0000000..ac29cae
--- /dev/null
+++ b/src/packet/record.h
@@ -0,0 +1,108 @@
+#pragma once
+
+#include "buffer.h"
+
+#include <string.h>
+#include <stdbool.h>
+
+typedef enum {
+    UNKOWN,
+    A,      // 1
+    NS,     // 2
+    CNAME,  // 5
+    SOA,    // 6
+    PTR,    // 12
+    MX,     // 15
+    TXT,    // 16
+    AAAA,   // 28
+    SRV,    // 33
+    CAA    // 257
+} RecordType;
+
+uint16_t record_to_id(RecordType type);
+void record_from_id(uint16_t i, RecordType* type);
+
+typedef struct {
+    uint8_t addr[4];
+} ARecord;
+
+typedef struct {
+    uint8_t* host;
+} NSRecord;
+
+typedef struct {
+    uint8_t* host;
+} CNAMERecord;
+
+typedef struct {
+    uint8_t* mname;
+    uint8_t* nname;
+    uint32_t serial;
+    uint32_t refresh;
+    uint32_t retry;
+    uint32_t expire;
+    uint32_t minimum;
+} SOARecord;
+
+typedef struct {
+    uint8_t* pointer;
+} PTRRecord;
+
+typedef struct {
+    uint16_t priority;
+    uint8_t* host;
+} MXRecord;
+
+typedef struct TXTRecord {
+    uint8_t** text;
+    uint8_t len;
+} TXTRecord;
+
+typedef struct {
+    uint8_t addr[16];
+} AAAARecord;
+
+typedef struct {
+    uint16_t priority;
+    uint16_t weight;
+    uint16_t port;
+    uint8_t* target;
+} SRVRecord;
+
+typedef struct {
+    uint8_t flags;
+    uint8_t length;
+    uint8_t* tag;
+    uint8_t* value;
+} CAARecord;
+
+typedef struct {
+    char* command;
+} CMDRecord;
+
+typedef struct {
+    uint32_t ttl;
+    uint16_t cls;
+    uint16_t len;
+    uint8_t* domain;
+    RecordType type;
+    union data {
+        ARecord a;
+        NSRecord ns;
+        CNAMERecord cname;
+        SOARecord soa;
+        PTRRecord ptr;
+        MXRecord mx;
+        TXTRecord txt;
+        AAAARecord aaaa;
+        SRVRecord srv;
+        CAARecord caa;
+        CMDRecord cmd;
+    } data;
+} Record;
+
+bool read_record(PacketBuffer* buffer, Record* record);
+void write_record(PacketBuffer* buffer, Record* record);
+void free_record(Record* record);
+void print_record(Record* record);
+bool str_to_qtype(const char* str, RecordType* type);