mirror of
https://github.com/rofl0r/proxychains-ng.git
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af5c6f0c6a
the central dns resolver function proxy_gethostbyname() used to iterate over the gethostent() db (/etc/hosts) on each dns request. since this is not threadsafe, we synchronized access to it previously using mutexes. the parsing of this file is slow, and blocking all threads to do it even moreso. since gethostent_r() is only available on a few platforms, i decided to read the hostent db once and then use a quick in-memory lookup on further usage. + some further refactoring.
61 lines
1.7 KiB
C
61 lines
1.7 KiB
C
#include <netdb.h>
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#include <stdio.h>
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#include <errno.h>
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#include "../src/common.h"
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/*
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int gethostent_r(
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struct hostent *ret, char *buf, size_t buflen,
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struct hostent **result, int *h_errnop);
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Glibc2 also has reentrant versions gethostent_r(), gethostbyaddr_r(),
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gethostbyname_r() and gethostbyname2_r().
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The caller supplies a hostent structure ret which will be filled in on success,
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and a temporary work buffer buf of size buflen.
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After the call, result will point to the result on success.
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In case of an error or if no entry is found result will be NULL.
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The functions return 0 on success and a nonzero error number on failure.
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In addition to the errors returned by the nonreentrant versions of these functions,
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if buf is too small, the functions will return ERANGE, and the call should be retried
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with a larger buffer.
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The global variable h_errno is not modified, but the address of a variable in which
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to store error numbers is passed in h_errnop.
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*/
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void printhostent(struct hostent *hp) {
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char ipbuf[16];
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pc_stringfromipv4(hp->h_addr_list[0], ipbuf);
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printf("alias: %p, len: %d, name: %s, addrlist: %p, addrtype: %d, ip: %s\n",
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hp->h_aliases,
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hp->h_length,
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hp->h_name,
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hp->h_addr_list,
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hp->h_addrtype,
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ipbuf
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);
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}
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int main(int argc, char** argv) {
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struct hostent he_buf;
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struct hostent *he_res;
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char h_buf[1024];
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int ch_errno;
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int ret;
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do {
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ret = gethostent_r(&he_buf, h_buf, sizeof(h_buf), &he_res, &ch_errno);
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printf("ret: %d, h_errno: %d\n", ret, ch_errno);
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if(ret != 0) {
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errno = ret;
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ret = -1;
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}
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if(ret == -1) {
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perror("gethostent_r");
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break;
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}
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if(he_res) {
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printhostent(he_res);
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}
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} while (he_res);
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return 0;
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} |