/* * $Id$ * * Low level DNS protocol routines * AUTHOR: Amos Jeffries, Rafael Martinez Torres * * SQUID Web Proxy Cache http://www.squid-cache.org/ * ---------------------------------------------------------- * * Squid is the result of efforts by numerous individuals from * the Internet community; see the CONTRIBUTORS file for full * details. Many organizations have provided support for Squid's * development; see the SPONSORS file for full details. Squid is * Copyrighted (C) 2001 by the Regents of the University of * California; see the COPYRIGHT file for full details. Squid * incorporates software developed and/or copyrighted by other * sources; see the CREDITS file for full details. * * This code is copyright (C) 2007 by Treehouse Networks Ltd of * New Zealand. It is published and Lisenced as an extension of * squid under the same conditions as the main squid application. * * 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 2 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, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA. * */ /* * KNOWN BUGS: * * UDP replies with TC set should be retried via TCP */ /** * April 2007 * * Provides RFC3596 functions to handle purely IPv6 DNS. * Adds AAAA and IPv6 PTR records. * Other IPv6 records are not mentioned by this RFC. * * IPv4 equivalents are taken care of by the RFC1035 library. * Where one protocol lookup must be followed by another, the caller * is resposible for the order and handling of the lookups. * */ #include "config.h" #include "util.h" #if HAVE_STDIO_H #include #endif #if HAVE_UNISTD_H #include #endif #if HAVE_STDLIB_H #include #endif #if HAVE_MEMORY_H #include #endif #if HAVE_SYS_TYPES_H #include #endif #if HAVE_ASSERT_H #include #endif #if HAVE_NETINET_IN_H #include #endif #if HAVE_STRINGS_H #include #endif #include "rfc3596.h" #ifndef SQUID_RFC1035_H #error RFC3596 Library depends on RFC1035 #endif /** * Builds a message buffer with a QUESTION to lookup records * for a hostname. Caller must allocate 'buf' which should * probably be at least 512 octets. The 'szp' initially * specifies the size of the buffer, on return it contains * the size of the message (i.e. how much to write). * Returns the size of the query */ ssize_t rfc3596BuildHostQuery(const char *hostname, char *buf, size_t sz, unsigned short qid, rfc1035_query * query, int qtype) { static rfc1035_message h; size_t offset = 0; memset(&h, '\0', sizeof(h)); h.id = qid; h.qr = 0; h.rd = 1; h.opcode = 0; /* QUERY */ h.qdcount = (unsigned int) 1; offset += rfc1035HeaderPack(buf + offset, sz - offset, &h); offset += rfc1035QuestionPack(buf + offset, sz - offset, hostname, qtype, RFC1035_CLASS_IN); if (query) { query->qtype = qtype; query->qclass = RFC1035_CLASS_IN; xstrncpy(query->name, hostname, sizeof(query->name)); } assert(offset <= sz); return offset; } /** * Builds a message buffer with a QUESTION to lookup A records * for a hostname. Caller must allocate 'buf' which should * probably be at least 512 octets. The 'szp' initially * specifies the size of the buffer, on return it contains * the size of the message (i.e. how much to write). * \return the size of the query */ ssize_t rfc3596BuildAQuery(const char *hostname, char *buf, size_t sz, unsigned short qid, rfc1035_query * query) { return rfc3596BuildHostQuery(hostname, buf, sz, qid, query, RFC1035_TYPE_A); } /** * Builds a message buffer with a QUESTION to lookup AAAA records * for a hostname. Caller must allocate 'buf' which should * probably be at least 512 octets. The 'szp' initially * specifies the size of the buffer, on return it contains * the size of the message (i.e. how much to write). * \return the size of the query */ ssize_t rfc3596BuildAAAAQuery(const char *hostname, char *buf, size_t sz, unsigned short qid, rfc1035_query * query) { return rfc3596BuildHostQuery(hostname, buf, sz, qid, query, RFC1035_TYPE_AAAA); } /** * Builds a message buffer with a QUESTION to lookup PTR records * for an address. Caller must allocate 'buf' which should * probably be at least 512 octets. The 'szp' initially * specifies the size of the buffer, on return it contains * the size of the message (i.e. how much to write). * \return the size of the query */ ssize_t rfc3596BuildPTRQuery4(const struct in_addr addr, char *buf, size_t sz, unsigned short qid, rfc1035_query * query) { static char rev[RFC1035_MAXHOSTNAMESZ]; unsigned int i; i = (unsigned int) ntohl(addr.s_addr); snprintf(rev, RFC1035_MAXHOSTNAMESZ, "%u.%u.%u.%u.in-addr.arpa.", i & 255, (i >> 8) & 255, (i >> 16) & 255, (i >> 24) & 255); return rfc3596BuildHostQuery(rev, buf, sz, qid, query, RFC1035_TYPE_PTR); } ssize_t rfc3596BuildPTRQuery6(const struct in6_addr addr, char *buf, size_t sz, unsigned short qid, rfc1035_query * query) { static char rev[RFC1035_MAXHOSTNAMESZ]; const uint8_t* r = addr.s6_addr; char* p = rev; int i; /* NP: MUST allow signed for loop termination. */ /* work from the raw addr field. anything else may have representation changes. */ /* The sin6_port and sin6_addr members shall be in network byte order. */ for (i = 15; i >= 0; i--, p+=4) { snprintf(p, 5, "%1x.%1x.", ((r[i])&0xf), (r[i]>>4)&0xf ); } snprintf(p,10,"ip6.arpa."); return rfc3596BuildHostQuery(rev, buf, sz, qid, query, RFC1035_TYPE_PTR); } #if DRIVER /* driver needs the rfc1035 code _without_ the main() */ # define main(a,b) rfc1035_main(a,b) # include "rfc1035.c" # undef main(a,b) #include #include int main(int argc, char *argv[]) { char input[512]; char buf[512]; char rbuf[512]; size_t sz = 512; unsigned short sid, sidb; int s; int rl; struct sockaddr* S; int var = 1; if ( argc < 3 || argc > 4) { fprintf(stderr, "usage: %s [-6|-4] ip port\n", argv[0]); return 1; } setbuf(stdout, NULL); setbuf(stderr, NULL); if (argv[var][0] == '-') { if (argv[var][1] == '4') prefer = AF_INET; else if (argv[var][1] == '6') prefer = AF_INET6; else { fprintf(stderr, "usage: %s [-6|-4] ip port\n", argv[0]); return 1; } var++; } s = socket(PF_INET, SOCK_DGRAM, 0); if (s < 0) { perror("socket"); return 1; } memset(&S, '\0', sizeof(S)); if (prefer == 6) { S = (struct sockaddr *) new sockaddr_in6; memset(S,0,sizeof(struct sockaddr_in6)); ((struct sockaddr_in6 *)S)->sin6_family = AF_INET6; ((struct sockaddr_in6 *)S)->sin6_port = htons(atoi(argv[var+1])); if ( ! xinet_pton(AF_INET6, argv[var], &((struct sockaddr_in6 *)S)->sin6_addr.s_addr) ) perror("listen address"); return 1; } s = socket(PF_INET6, SOCK_DGRAM, 0); } else { S = (struct sockaddr *) new sockaddr_in; memset(S,0,sizeof(struct sockaddr_in)); ((struct sockaddr_in *)S)->sin_family = AF_INET; ((struct sockaddr_in *)S)->sin_port = htons(atoi(argv[var+1])); if ( ! xinet_pton(AF_INET, argv[var], &((struct sockaddr_in *)S)->sin_addr.s_addr) ) perror("listen address"); return 1; } } while (fgets(input, 512, stdin)) { struct in6_addr junk6; struct in_addr junk4; strtok(input, "\r\n"); memset(buf, '\0', 512); sz = 512; if (xinet_pton(AF_INET6, input, &junk6)) { sid = rfc1035BuildPTRQuery6(junk6, buf, &sz); sidb=0; } else if (xinet_pton(AF_INET, input, &junk4)) { sid = rfc1035BuildPTRQuery4(junk4, buf, &sz); sidb=0; } else { sid = rfc1035BuildAAAAQuery(input, buf, &sz); sidb = rfc1035BuildAQuery(input, buf, &sz); } sendto(s, buf, sz, 0, S, sizeof(*S)); do { fd_set R; struct timeval to; FD_ZERO(&R); FD_SET(s, &R); to.tv_sec = 10; to.tv_usec = 0; rl = select(s + 1, &R, NULL, NULL, &to); } while (0); if (rl < 1) { printf("TIMEOUT\n"); continue; } memset(rbuf, '\0', 512); rl = recv(s, rbuf, 512, 0); { unsigned short rid = 0; int i; int n; rfc1035_rr *answers = NULL; n = rfc1035AnswersUnpack(rbuf, rl, &answers, &rid); if (n < 0) { printf("ERROR %d\n", rfc1035_errno); } else if (rid != sid && rid != sidb) { printf("ERROR, ID mismatch (%#hx, %#hx)\n", sid, rid); printf("ERROR, ID mismatch (%#hx, %#hx)\n", sidb, rid); } else { printf("%d answers\n", n); for (i = 0; i < n; i++) { if (answers[i].type == RFC1035_TYPE_A) { struct in_addr a; char tmp[16]; memcpy(&a, answers[i].rdata, 4); printf("A\t%d\t%s\n", answers[i].ttl, inet_ntop(AF_INET,&a,tmp,16)); } else if (answers[i].type == RFC1035_TYPE_AAAA) { struct in6_addr a; char tmp[INET6_ADDRSTRLEN]; memcpy(&a, answers[i].rdata, 16); printf("AAAA\t%d\t%s\n", answers[i].ttl, inet_ntop(AF_INET6,&a,tmp,sizeof(tmp))); } else if (answers[i].type == RFC1035_TYPE_PTR) { char ptr[RFC1035_MAXHOSTNAMESZ]; strncpy(ptr, answers[i].rdata, answers[i].rdlength); printf("PTR\t%d\t%s\n", answers[i].ttl, ptr); } else if (answers[i].type == RFC1035_TYPE_CNAME) { char ptr[RFC1035_MAXHOSTNAMESZ]; strncpy(ptr, answers[i].rdata, answers[i].rdlength); printf("CNAME\t%d\t%s\n", answers[i].ttl, ptr); } else { fprintf(stderr, "can't print answer type %d\n", (int) answers[i].type); } } } } } return 0; } #endif