commit 7d650d5d9bcba940ae312657d51e366e7401fd6b Author: Tyler Murphy Date: Mon Apr 17 22:49:49 2023 -0400 first diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..ba077a4 --- /dev/null +++ b/.gitignore @@ -0,0 +1 @@ +bin diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..f288702 --- /dev/null +++ b/LICENSE @@ -0,0 +1,674 @@ + GNU GENERAL PUBLIC LICENSE + Version 3, 29 June 2007 + + Copyright (C) 2007 Free Software Foundation, Inc. + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The GNU General Public License is a free, copyleft license for +software and other kinds of works. + + The licenses for most software and other practical works are designed +to take away your freedom to share and change the works. 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Interpretation of Sections 15 and 16. + + If the disclaimer of warranty and limitation of liability provided +above cannot be given local legal effect according to their terms, +reviewing courts shall apply local law that most closely approximates +an absolute waiver of all civil liability in connection with the +Program, unless a warranty or assumption of liability accompanies a +copy of the Program in return for a fee. + + END OF TERMS AND CONDITIONS + + How to Apply These Terms to Your New Programs + + If you develop a new program, and you want it to be of the greatest +possible use to the public, the best way to achieve this is to make it +free software which everyone can redistribute and change under these terms. + + To do so, attach the following notices to the program. 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If not, see . + +Also add information on how to contact you by electronic and paper mail. + + If the program does terminal interaction, make it output a short +notice like this when it starts in an interactive mode: + + Copyright (C) + This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands `show w' and `show c' should show the appropriate +parts of the General Public License. Of course, your program's commands +might be different; for a GUI interface, you would use an "about box". + + You should also get your employer (if you work as a programmer) or school, +if any, to sign a "copyright disclaimer" for the program, if necessary. +For more information on this, and how to apply and follow the GNU GPL, see +. + + The GNU General Public License does not permit incorporating your program +into proprietary programs. If your program is a subroutine library, you +may consider it more useful to permit linking proprietary applications with +the library. If this is what you want to do, use the GNU Lesser General +Public License instead of this License. But first, please read +. diff --git a/Makefile b/Makefile new file mode 100644 index 0000000..a767001 --- /dev/null +++ b/Makefile @@ -0,0 +1,42 @@ +CC = gcc + +INCFLAGS = -Isrc + +CCFLAGS = -std=gnu99 -Wall -Wextra -pedantic -O2 +CCFLAGS += $(INCFLAGS) + +LDFLAGS += $(INCFLAGS) + +BIN = bin +APP = $(BIN)/app +SRC = $(shell find src -name "*.c") +OBJ = $(SRC:%.c=$(BIN)/%.o) + +.PHONY: dirs run clean build install uninstall + +EOF: clean build + +dirs: + mkdir -p ./$(BIN) + mkdir -p ./$(BIN)/src + mkdir -p ./$(BIN)/src/packet + mkdir -p ./$(BIN)/src/client + +run: build + $(APP) + +build: dirs ${OBJ} + ${CC} -o $(APP) $(filter %.o,$^) $(LDFLAGS) + +$(BIN)/%.o: %.c + $(CC) -o $@ -c $< $(CCFLAGS) + +clean: + rm -rf $(APP) + rm -rf $(BIN) + +install: + cp $(APP) /usr/local/bin/wig + +uninstall: + rm /usr/local/bin/wig diff --git a/readme.md b/readme.md new file mode 100644 index 0000000..0e31dc6 --- /dev/null +++ b/readme.md @@ -0,0 +1,37 @@ + +# Wig + +A simple and lightweight dns client written in C + +## How to + +`usage: wig [@server] [options] domain [qtype]` + +For simple usage, just type the domain name followed by the record type: `example.com AAAA`. Or you can just type the domain, `example.com`, and it will default to the A record. + +If you want to use a custom dns server, just specify the ip or domain after the @ like `@1.1.1.1` or `@ns1.google.com`. + +If you want to specify a port, you can add `-p port_num`. + +Finally, if you want to force tcp, you can add `-t`. + +## License + +This project is Licensed under the [GPLv3](https://www.gnu.org/licenses/gpl-3.0.en.html) + +## Compilation + +Wig only runs on Linux systems that are Posix 1995 compliant + +Make sure to have `gcc` and `make` installed, and then run + +```shell +$ make # compiles the program +$ sudo make install # installs the binary +``` + +If you wish to remove the program, you can run + +```shell +$ sudo make uninstall # removes the binary +``` 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#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 +#include +#include +#include + +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 +#include +#include +#include +#include +#include +#include + +#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 + +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 +#include +#include +#include +#include +#include +#include +#include + +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 +#include +#include +#include + +#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 +#include +#include + +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 + +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 +#include +#include +#include +#include + +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 + +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 +#include +#include +#include + +#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 + +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 +#include +#include +#include + +#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 +#include +#include +#include +#include + +#undef _POSIX_C_SOURCE +#include + +#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 +#include + +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);