From 2f11edb447bf9905ea1ccade2abb31a6a43801b7 Mon Sep 17 00:00:00 2001 From: xHire Date: Tue, 16 May 2017 09:07:45 +0200 Subject: [PATCH] Dropped deprecated dnsproxy --- src/dnsproxy.c | 477 ------------------------------------------------- 1 file changed, 477 deletions(-) delete mode 100644 src/dnsproxy.c diff --git a/src/dnsproxy.c b/src/dnsproxy.c deleted file mode 100644 index 8bf245f..0000000 --- a/src/dnsproxy.c +++ /dev/null @@ -1,477 +0,0 @@ -/* - * WrapSix - * Copyright (C) 2008-2010 xHire - * - * This program is free software: you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation, either version 3 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program. If not, see . - */ - -#include -#include -#include /* inet_pton */ -#include /* close */ -#include /* memcpy */ -#include /* malloc */ - -struct s_dns_header { - unsigned short id; /* 16 b; identifier of a request */ - unsigned short flags; /* 16 b */ - unsigned short question; /* 16 b; num of data in question sec */ - unsigned short answer; /* 16 b; num of RRs in answer sec */ - unsigned short auth; /* 16 b; num of RRs in authority sec */ - unsigned short add; /* 16 b; num of RRs in additional sec */ -} __attribute__ ((__packed__)); - -struct s_dns_answer { - char *fqdn; /* domain name of the record */ - unsigned short dnlength; /* length of the domain name */ - unsigned short type; /* 16 b; RR type code */ - unsigned short class; /* 16 b; class of the data in rdata */ - unsigned int ttl; /* 32 b; RR caching interval */ - unsigned short rdlength; /* 16 b; length of the rdata section */ - char *rdata; /* describes the resource */ -} __attribute__ ((__packed__)); - -#define BUFFER_SIZE 512 /* maximum of a DNS packet */ -#define IP "::2" -#define RESOLVER "::1" -#define PORT 53 -#define PREFIX "::" - -unsigned short id = 0; - -int resolver_connect(int *sock, struct sockaddr_in6 *sock_addr); -int udp_receive(int *sock, struct sockaddr_in6 *sock_addr, char *buffer, int *length); -int udp_send(int *sock, struct sockaddr_in6 *sock_addr, char *data, int length); -int lookup(unsigned short qtype, char *data, struct s_dns_answer **answer, unsigned short *answer_count); -int get_fqdn(char *fqdn, char *data, unsigned short *length); - -int resolver_connect(int *sock, struct sockaddr_in6 *sock_addr) -{ - int tmp_sock; - struct sockaddr_in6 tmp_sock_addr; - char resolver[] = RESOLVER; - - /* create a socket */ - if ((tmp_sock = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP)) == -1) { - fprintf(stderr, "[Error] Unable to create UDP socket for outgoing connections\n"); - return 1; - } - - /* setup the socket */ - tmp_sock_addr.sin6_family = AF_INET6; - tmp_sock_addr.sin6_port = htons(PORT); - inet_pton(AF_INET6, (char *) &resolver, &(tmp_sock_addr.sin6_addr)); - - /* return correct data */ - memcpy(sock, &tmp_sock, sizeof(int)); - memcpy(sock_addr, &tmp_sock_addr, sizeof(struct sockaddr_in6)); - - return 0; -} - -int udp_receive(int *sock, struct sockaddr_in6 *sock_addr, char *buffer, int *length) -{ - int tmp_length; - int addrlen; - - addrlen = sizeof(struct sockaddr_in6); - if ((tmp_length = recvfrom(*sock, buffer, BUFFER_SIZE, 0, (struct sockaddr *) sock_addr, (socklen_t *) &addrlen)) == -1) { - char str_ip[128]; - inet_ntop(AF_INET6, &(sock_addr->sin6_addr), (char *) &str_ip, 128); - - fprintf(stderr, "[Error] Unable to read from UDP socket [%s]:%d\n", str_ip, PORT); - - return 1; - } - - memcpy(length, &tmp_length, sizeof(int)); - - return 0; -} - -int udp_send(int *sock, struct sockaddr_in6 *sock_addr, char *data, int length) -{ - int addrlen; - - addrlen = sizeof(struct sockaddr_in6); - if (sendto(*sock, data, length, 0, (struct sockaddr *) sock_addr, addrlen) != length) { - char str_ip[128]; - inet_ntop(AF_INET6, &(sock_addr->sin6_addr), (char *) &str_ip, 128); - - fprintf(stderr, "[Error] Unable to write to UDP socket [%s]:%d\n", str_ip, PORT); - return 1; - } - - return 0; -} - -int lookup(unsigned short qtype, char *data, struct s_dns_answer **answer, unsigned short *answer_count) -{ - int i, j; - unsigned short length; - unsigned short qclass; - - int resolver_sock; - struct sockaddr_in6 resolver_sock_addr; - - char buffer[BUFFER_SIZE]; - struct s_dns_header *header; - struct s_dns_answer *answers; - - header = (struct s_dns_header *) &buffer; - - /* create the request */ - header->id = htons(++id); - header->flags = htons(0x0100); /* recursion desired */ - header->question = htons(1); - header->answer = 0; - header->auth = 0; - header->add = 0; - - /* copy the fqdn from 'data' */ - for (i = sizeof(struct s_dns_header), length = i, j = 0;; i++, j++) { - buffer[i] = data[j]; - - if (length == i) { - length += buffer[i] + 1; - - if (buffer[i] == 0x0) { - break; - } - } - } - - /* set the rest fields of the question section */ - qtype = htons(qtype); - qclass = htons(0x1); - memcpy(&buffer[i + 1], &qtype, 2); - memcpy(&buffer[i + 3], &qclass, 2); - - /* create a connection socket */ - resolver_connect(&resolver_sock, &resolver_sock_addr); - - /* send the request */ - udp_send(&resolver_sock, &resolver_sock_addr, (char *) &buffer, i + 5); - - /* fetch the answer */ - udp_receive(&resolver_sock, &resolver_sock_addr, (char *) &buffer, (int *) &length); - - /* close the socket */ - close(resolver_sock); - - /* process the answer */ - header = (struct s_dns_header *) &buffer; - header->answer = htons(header->answer); - if (htons(header->id) == id && header->answer > 0) { - if ((answers = (struct s_dns_answer *) malloc(header->answer * sizeof(struct s_dns_answer))) == NULL) { - fprintf(stderr, "[Error] Lack of free memory\n"); - return 1; - } - - /* save the count of the answers */ - memcpy(answer_count, &header->answer, sizeof(unsigned short)); - - /* first go over the question section */ - j = sizeof(struct s_dns_header); - if (htons(header->question) > 0) { - while (buffer[j] != 0x0) { - j += buffer[j] + 1; - } - - /* set the position of answer section */ - j += 5; - } - - /* go through all answers and process them */ - for (i = 0; i < header->answer; i++) { - /* is the answer compressed? save the fqdn in both cases */ - if (buffer[j] & 0xc0) { - get_fqdn((char *) &(answers[i].fqdn), &buffer[(int) buffer[j + 1]], &(answers[i].dnlength)); - j += 2; - } else { - get_fqdn((char *) &(answers[i].fqdn), &buffer[j], &(answers[i].dnlength)); - j += answers[i].dnlength; - } - - /* save the rest of the answer */ - memcpy(&(answers[i].type), &buffer[j], 2); - memcpy(&(answers[i].class), &buffer[j + 2], 2); - memcpy(&(answers[i].ttl), &buffer[j + 4], 4); - memcpy(&(answers[i].rdlength), &buffer[j + 8], 2); - answers[i].rdlength = htons(answers[i].rdlength); - - if ((answers[i].rdata = (char *) malloc(answers[i].rdlength)) == NULL) { - fprintf(stderr, "[Error] Lack of free memory\n"); - return 1; - } - - memcpy(answers[i].rdata, &buffer[j + 10], answers[i].rdlength); - - j += 10 + answers[i].rdlength; - } - - /* return address of array of answers */ - memcpy(answer, &answers, sizeof(struct s_dns_answer *)); - } else { - return 1; - } - - return 0; -} - -int get_fqdn(char *fqdn, char *data, unsigned short *length) -{ - unsigned short i, offset; - char buffer[BUFFER_SIZE]; - char *tmp; - - offset = 0; - - /* read the fqdn and save it into the buffer */ - for (i = 0; data[i] != 0x0; i++) { - buffer[i] = data[i]; - - if (i == offset) { - offset += data[i] + 1; - } - } - - /* don't forget to add the ending octet */ - buffer[offset] = 0x0; - offset++; - - /* create a storage to save the fqdn */ - if ((tmp = (char *) malloc(offset)) == NULL) { - fprintf(stderr, "[Error] Lack of free memory\n"); - return 1; - } - - /* save length of the fqdn */ - memcpy(length, &offset, sizeof(unsigned short)); - - /* save the fqdn */ - memcpy(tmp, &buffer, *length); - - /* save the address of the storage of the fqdn */ - memcpy(fqdn, &tmp, sizeof(char *)); - - return 0; -} - -int main(int argc, char **argv) -{ - int i, j; - int length, offset; - unsigned short k; - unsigned short answer_count; - - char ip[] = IP; - char buffer[BUFFER_SIZE]; - char buffer_answer[BUFFER_SIZE]; - - int sock; - struct sockaddr_in6 sock_addr, - client_sock_addr; - - int resolver_sock; - struct sockaddr_in6 resolver_sock_addr; - - struct s_dns_header *dns, *dns_answer; - unsigned short qtype, qclass; - struct s_dns_answer *answers; - - struct in6_addr ipv6_prefix; - - /* initialization */ - inet_pton(AF_INET6, PREFIX, &ipv6_prefix); - - /* create the socket */ - if ((sock = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP)) == -1) { - fprintf(stderr, "[Error] Unable to create UDP socket\n"); - return 1; - } - - /* setup the socket */ - sock_addr.sin6_family = AF_INET6; - sock_addr.sin6_port = htons(PORT); - inet_pton(AF_INET6, (char *) &ip, &(sock_addr.sin6_addr)); - - /* bind the socket to address and port */ - if (bind(sock, (struct sockaddr *) &(sock_addr), sizeof(sock_addr)) == -1) { - fprintf(stderr, "[Error] Unable to bind UDP socket to %s:%d\n", IP, PORT); - return 1; - } - - for (;;) { - /* fetch a request */ - udp_receive(&sock, &client_sock_addr, (char *) &buffer, &length); - - /* process the request */ - dns = (struct s_dns_header *) &buffer; - /* TODO: there could be more than one question */ - offset = sizeof(struct s_dns_header); - while (buffer[offset] != 0x0) { - offset += buffer[offset] + 1; - } - memcpy(&qtype, &buffer[offset + 1], 2); - memcpy(&qclass, &buffer[offset + 3], 2); - qtype = htons(qtype); - qclass = htons(qclass); - - /* this is AAAA request */ - if (qclass == 0x1 && qtype == 0x1c) { - answers = NULL; - /* first look up if some AAAA exists */ - if (lookup(0x1c, &buffer[sizeof(struct s_dns_header)], &answers, &answer_count) == 0) { - /* send back an answer */ - dns_answer = (struct s_dns_header *) &buffer_answer; - dns_answer->id = dns->id; - dns_answer->flags = htons(0x8180); - dns_answer->question = htons(1); - dns_answer->answer = htons(answer_count); - dns_answer->auth = 0; - dns_answer->add = 0; - - /* copy question section */ - i = offset - sizeof(struct s_dns_header) + 5; - memcpy(&buffer_answer[sizeof(struct s_dns_header)], &buffer[sizeof(struct s_dns_header)], i); - - /* construct answer section */ - i = offset + 5; - for (j = 0; j < answer_count; j++) { - /* copy fqdn */ - memcpy(&buffer_answer[i], answers[j].fqdn, answers[j].dnlength); - i += answers[j].dnlength; - - /* copy type, class and ttl */ - memcpy(&buffer_answer[i], &(answers[j].type), 2 * sizeof(unsigned short) + sizeof(unsigned int)); - i += 2 * sizeof(unsigned short) + sizeof(unsigned int); - - /* copy rdlength */ - k = htons(answers[j].rdlength); - memcpy(&buffer_answer[i], &k, sizeof(unsigned short)); - i += sizeof(unsigned short); - - /* copy rdata */ - memcpy(&buffer_answer[i], answers[j].rdata, answers[j].rdlength); - i += answers[j].rdlength; - - /* memory clean-up */ - free(answers[j].fqdn); - free(answers[j].rdata); - } - - /* send it */ - udp_send(&sock, &client_sock_addr, (char *) &buffer_answer, i); - - /* memory clean-up */ - free(answers); - /* second look up if some A exists & transform it */ - } else if (lookup(0x1, &buffer[sizeof(struct s_dns_header)], &answers, &answer_count) == 0) { - /* send back an answer */ - dns_answer = (struct s_dns_header *) &buffer_answer; - dns_answer->id = dns->id; - dns_answer->flags = htons(0x8180); - dns_answer->question = htons(1); - dns_answer->answer = htons(answer_count); - dns_answer->auth = 0; - dns_answer->add = 0; - - /* copy question section */ - i = offset - sizeof(struct s_dns_header) + 5; - memcpy(&buffer_answer[sizeof(struct s_dns_header)], &buffer[sizeof(struct s_dns_header)], i); - - /* construct answer section */ - i = offset + 5; - for (j = 0; j < answer_count; j++) { - /* copy fqdn */ - memcpy(&buffer_answer[i], answers[j].fqdn, answers[j].dnlength); - i += answers[j].dnlength; - - /* set type */ - k = htons(0x1c); - memcpy(&buffer_answer[i], &k, sizeof(unsigned short)); - i += sizeof(unsigned short); - - /* copy class and ttl */ - memcpy(&buffer_answer[i], &(answers[j].class), sizeof(unsigned short) + sizeof(unsigned int)); - i += sizeof(unsigned short) + sizeof(unsigned int); - - /* set rdlength */ - k = htons(sizeof(ipv6_prefix)); - memcpy(&buffer_answer[i], &k, sizeof(unsigned short)); - i += sizeof(unsigned short); - - /* copy IPv6 prefix */ - memcpy(&buffer_answer[i], &ipv6_prefix, sizeof(ipv6_prefix) - answers[j].rdlength); - i += sizeof(ipv6_prefix) - answers[j].rdlength; - - /* copy IPv4 address */ - memcpy(&buffer_answer[i], answers[j].rdata, answers[j].rdlength); - i += answers[j].rdlength; - - /* memory clean-up */ - free(answers[j].fqdn); - free(answers[j].rdata); - } - - /* send it */ - udp_send(&sock, &client_sock_addr, (char *) &buffer_answer, i); - - /* memory clean-up */ - free(answers); - /* third say we have no clue about the fqdn */ - } else { - /* send back an answer */ - dns_answer = (struct s_dns_header *) &buffer_answer; - dns_answer->id = dns->id; - dns_answer->flags = htons(0x8183); - dns_answer->question = htons(1); - dns_answer->answer = 0; - dns_answer->auth = 0; - dns_answer->add = 0; - - /* copy question section */ - i = offset - sizeof(struct s_dns_header) + 5; - memcpy(&buffer_answer[sizeof(struct s_dns_header)], &buffer[sizeof(struct s_dns_header)], i); - i += sizeof(struct s_dns_header); - - /* send it */ - udp_send(&sock, &client_sock_addr, (char *) &buffer_answer, i); - } - /* this is other than AAAA request -> just proxy it */ - } else { - /* create a connection socket */ - resolver_connect(&resolver_sock, &resolver_sock_addr); - - /* send the request */ - udp_send(&resolver_sock, &resolver_sock_addr, (char *) &buffer, length); - - /* fetch the answer */ - udp_receive(&resolver_sock, &resolver_sock_addr, (char *) &buffer, (int *) &length); - - /* close the socket */ - close(resolver_sock); - - - /* forward the answer to the client */ - udp_send(&sock, &client_sock_addr, (char *) &buffer, length); - } - } - - /* final clean-up */ - close(sock); - - return 0; -}