diff options
Diffstat (limited to 'resolv')
| -rw-r--r-- | resolv/res_mkquery.c | 284 |
1 files changed, 140 insertions, 144 deletions
diff --git a/resolv/res_mkquery.c b/resolv/res_mkquery.c index 2e3aa39cf0..a601b69885 100644 --- a/resolv/res_mkquery.c +++ b/resolv/res_mkquery.c @@ -97,172 +97,168 @@ # define RANDOM_BITS(Var) { uint64_t v64; HP_TIMING_NOW (v64); Var = v64; } #endif -/* - * Form all types of queries. - * Returns the size of the result or -1. - */ +/* Form all types of queries. Returns the size of the result or -1 on + error. + + STATP points to an initialized resolver state. OP is the opcode of + the query. DNAME is the domain. CLASS and TYPE are the DNS query + class and type. DATA can be NULL; otherwise, it is a pointer to a + domain name which is included in the generated packet (if op == + NS_NOTIFY_OP). BUF must point to the out buffer of BUFLEN bytes. + + DATALEN and NEWRR_IN are currently ignored. */ int -res_nmkquery(res_state statp, - int op, /* opcode of query */ - const char *dname, /* domain name */ - int class, int type, /* class and type of query */ - const u_char *data, /* resource record data */ - int datalen, /* length of data */ - const u_char *newrr_in, /* new rr for modify or append */ - u_char *buf, /* buffer to put query */ - int buflen) /* size of buffer */ +res_nmkquery (res_state statp, int op, const char *dname, + int class, int type, + const unsigned char *data, int datalen, + const unsigned char *newrr_in, + unsigned char *buf, int buflen) { - HEADER *hp; - u_char *cp; - int n; - u_char *dnptrs[20], **dpp, **lastdnptr; + HEADER *hp; + unsigned char *cp; + int n; + unsigned char *dnptrs[20], **dpp, **lastdnptr; - if (class < 0 || class > 65535 - || type < 0 || type > 65535) - return -1; + if (class < 0 || class > 65535 || type < 0 || type > 65535) + return -1; - /* - * Initialize header fields. - */ - if ((buf == NULL) || (buflen < HFIXEDSZ)) - return (-1); - memset(buf, 0, HFIXEDSZ); - hp = (HEADER *) buf; - /* We randomize the IDs every time. The old code just - incremented by one after the initial randomization which - still predictable if the application does multiple - requests. */ - int randombits; - do - { + /* Initialize header fields. */ + if ((buf == NULL) || (buflen < HFIXEDSZ)) + return -1; + memset (buf, 0, HFIXEDSZ); + hp = (HEADER *) buf; + /* We randomize the IDs every time. The old code just incremented + by one after the initial randomization which still predictable if + the application does multiple requests. */ + int randombits; + do + { #ifdef RANDOM_BITS - RANDOM_BITS (randombits); + RANDOM_BITS (randombits); #else - struct timeval tv; - __gettimeofday (&tv, NULL); - randombits = (tv.tv_sec << 8) ^ tv.tv_usec; + struct timeval tv; + __gettimeofday (&tv, NULL); + randombits = (tv.tv_sec << 8) ^ tv.tv_usec; #endif - } - while ((randombits & 0xffff) == 0); - statp->id = (statp->id + randombits) & 0xffff; - hp->id = statp->id; - hp->opcode = op; - hp->rd = (statp->options & RES_RECURSE) != 0; - hp->rcode = NOERROR; - cp = buf + HFIXEDSZ; - buflen -= HFIXEDSZ; - dpp = dnptrs; - *dpp++ = buf; - *dpp++ = NULL; - lastdnptr = dnptrs + sizeof dnptrs / sizeof dnptrs[0]; - /* - * perform opcode specific processing - */ - switch (op) { - case NS_NOTIFY_OP: - if ((buflen -= QFIXEDSZ + (data == NULL ? 0 : RRFIXEDSZ)) < 0) - return (-1); - goto compose; + } + while ((randombits & 0xffff) == 0); + + statp->id = (statp->id + randombits) & 0xffff; + hp->id = statp->id; + hp->opcode = op; + hp->rd = (statp->options & RES_RECURSE) != 0; + hp->rcode = NOERROR; + cp = buf + HFIXEDSZ; + buflen -= HFIXEDSZ; + dpp = dnptrs; + *dpp++ = buf; + *dpp++ = NULL; + lastdnptr = dnptrs + sizeof dnptrs / sizeof dnptrs[0]; - case QUERY: - if ((buflen -= QFIXEDSZ) < 0) - return (-1); - compose: - n = ns_name_compress(dname, cp, buflen, - (const u_char **) dnptrs, - (const u_char **) lastdnptr); - if (n < 0) - return (-1); - cp += n; - buflen -= n; - NS_PUT16 (type, cp); - NS_PUT16 (class, cp); - hp->qdcount = htons(1); - if (op == QUERY || data == NULL) - break; - /* - * Make an additional record for completion domain. - */ - n = ns_name_compress((char *)data, cp, buflen, - (const u_char **) dnptrs, - (const u_char **) lastdnptr); - if (__glibc_unlikely (n < 0)) - return (-1); - cp += n; - buflen -= n; - NS_PUT16 (T_NULL, cp); - NS_PUT16 (class, cp); - NS_PUT32 (0, cp); - NS_PUT16 (0, cp); - hp->arcount = htons(1); - break; + /* Perform opcode specific processing. */ + switch (op) + { + case NS_NOTIFY_OP: + if ((buflen -= QFIXEDSZ + (data == NULL ? 0 : RRFIXEDSZ)) < 0) + return -1; + goto compose; - default: - return (-1); - } - return (cp - buf); + case QUERY: + if ((buflen -= QFIXEDSZ) < 0) + return -1; + compose: + n = ns_name_compress (dname, cp, buflen, + (const unsigned char **) dnptrs, + (const unsigned char **) lastdnptr); + if (n < 0) + return -1; + cp += n; + buflen -= n; + NS_PUT16 (type, cp); + NS_PUT16 (class, cp); + hp->qdcount = htons (1); + if (op == QUERY || data == NULL) + break; + + /* Make an additional record for completion domain. */ + n = ns_name_compress ((char *)data, cp, buflen, + (const unsigned char **) dnptrs, + (const unsigned char **) lastdnptr); + if (__glibc_unlikely (n < 0)) + return -1; + cp += n; + buflen -= n; + NS_PUT16 (T_NULL, cp); + NS_PUT16 (class, cp); + NS_PUT32 (0, cp); + NS_PUT16 (0, cp); + hp->arcount = htons (1); + break; + + default: + return -1; + } + return cp - buf; } libresolv_hidden_def (res_nmkquery) +/* Create an OPT resource record. Return the length of the final + packet, or -1 on error. -/* attach OPT pseudo-RR, as documented in RFC2671 (EDNS0). */ -#ifndef T_OPT -#define T_OPT 41 -#endif - + STATP must be an initialized resolver state. N0 is the current + number of bytes of the packet (already written to BUF by the + aller). BUF is the packet being constructed. The array it + pointers to must be BUFLEN bytes long. ANSLEN is the advertised + EDNS buffer size (to be included in the OPT resource record). */ int -__res_nopt(res_state statp, - int n0, /* current offset in buffer */ - u_char *buf, /* buffer to put query */ - int buflen, /* size of buffer */ - int anslen) /* UDP answer buffer size */ +__res_nopt (res_state statp, int n0, unsigned char *buf, int buflen, + int anslen) { - u_int16_t flags = 0; - - HEADER *hp = (HEADER *) buf; - u_char *cp = buf + n0; - u_char *ep = buf + buflen; + uint16_t flags = 0; + HEADER *hp = (HEADER *) buf; + unsigned char *cp = buf + n0; + unsigned char *ep = buf + buflen; - if ((ep - cp) < 1 + RRFIXEDSZ) - return -1; + if ((ep - cp) < 1 + RRFIXEDSZ) + return -1; - *cp++ = 0; /* "." */ + /* Add the root label. */ + *cp++ = 0; - NS_PUT16(T_OPT, cp); /* TYPE */ + NS_PUT16 (T_OPT, cp); /* Record type. */ - /* Lowering the advertised buffer size based on the actual - answer buffer size is desirable because the server will - minimize the reply to fit into the UDP packet (and A - non-minimal response might not fit the buffer). + /* Lowering the advertised buffer size based on the actual + answer buffer size is desirable because the server will + minimize the reply to fit into the UDP packet (and A + non-minimal response might not fit the buffer). - The RESOLV_EDNS_BUFFER_SIZE limit could still result in TCP - fallback and a non-minimal response which has to be - hard-truncated in the stub resolver, but this is price to - pay for avoiding fragmentation. (This issue does not - affect the nss_dns functions because they use the stub - resolver in such a way that it allocates a properly sized - response buffer.) */ - { - uint16_t buffer_size; - if (anslen < 512) - buffer_size = 512; - else if (anslen > RESOLV_EDNS_BUFFER_SIZE) - buffer_size = RESOLV_EDNS_BUFFER_SIZE; - else - buffer_size = anslen; - NS_PUT16 (buffer_size, cp); - } + The RESOLV_EDNS_BUFFER_SIZE limit could still result in TCP + fallback and a non-minimal response which has to be + hard-truncated in the stub resolver, but this is price to + pay for avoiding fragmentation. (This issue does not + affect the nss_dns functions because they use the stub + resolver in such a way that it allocates a properly sized + response buffer.) */ + { + uint16_t buffer_size; + if (anslen < 512) + buffer_size = 512; + else if (anslen > RESOLV_EDNS_BUFFER_SIZE) + buffer_size = RESOLV_EDNS_BUFFER_SIZE; + else + buffer_size = anslen; + NS_PUT16 (buffer_size, cp); + } - *cp++ = NOERROR; /* extended RCODE */ - *cp++ = 0; /* EDNS version */ + *cp++ = NOERROR; /* Extended RCODE. */ + *cp++ = 0; /* EDNS version. */ - if (statp->options & RES_USE_DNSSEC) { - flags |= NS_OPT_DNSSEC_OK; - } + if (statp->options & RES_USE_DNSSEC) + flags |= NS_OPT_DNSSEC_OK; - NS_PUT16(flags, cp); - NS_PUT16(0, cp); /* RDLEN */ - hp->arcount = htons(ntohs(hp->arcount) + 1); + NS_PUT16 (flags, cp); + NS_PUT16 (0, cp); /* RDATA length (no options are preent). */ + hp->arcount = htons (ntohs (hp->arcount) + 1); - return cp - buf; + return cp - buf; } |