diff options
| -rw-r--r-- | CHANGES | 3 | ||||
| -rw-r--r-- | Makefile.inc | 1 | ||||
| -rw-r--r-- | RELEASE-NOTES | 3 | ||||
| -rw-r--r-- | ares.h | 11 | ||||
| -rw-r--r-- | ares_parse_srv_reply.3 | 78 | ||||
| -rw-r--r-- | ares_parse_srv_reply.c | 159 |
6 files changed, 253 insertions, 2 deletions
@@ -1,5 +1,8 @@ Changelog for the c-ares project +* 4 Sep 2009 (Daniel Stenberg) +- Jakub Hrozek added ares_parse_srv_reply() for SRV parsing + * 3 Aug 2009 (Daniel Stenberg) - Joshua Kwan fixed the init routine to fill in the defaults for stuff that fails to get inited by other means. This fixes a case of when the c-ares diff --git a/Makefile.inc b/Makefile.inc index a701ed6..de3be27 100644 --- a/Makefile.inc +++ b/Makefile.inc @@ -22,6 +22,7 @@ CSOURCES = ares__close_sockets.c \ ares_parse_aaaa_reply.c \ ares_parse_ns_reply.c \ ares_parse_ptr_reply.c \ + ares_parse_srv_reply.c \ ares_process.c \ ares_query.c \ ares_search.c \ diff --git a/RELEASE-NOTES b/RELEASE-NOTES index cfd4a95..4eef954 100644 --- a/RELEASE-NOTES +++ b/RELEASE-NOTES @@ -10,6 +10,7 @@ Changed: o new ares_library_init() and ares_library_cleanup() functions o new --enable-curldebug configure option o ARES_ECANCELLED is now sent as reason for ares_cancel() + o added ares_parse_srv_reply() Fixed: @@ -22,6 +23,6 @@ Fixed: Thanks go to these friendly people for their efforts and contributions: Phil Blundell, Japheth Cleaver, Yang Tse, Gregor Jasny, Joshua Kwan, - Timo Teras + Timo Teras, Jakub Hrozek Have fun! @@ -1,6 +1,6 @@ /* $Id$ */ -/* Copyright 1998 by the Massachusetts Institute of Technology. +/* Copyright 1998, 2009 by the Massachusetts Institute of Technology. * Copyright (C) 2007-2009 by Daniel Stenberg * * Permission to use, copy, modify, and distribute this @@ -322,6 +322,13 @@ struct addr6ttl { int ttl; }; +struct srv_reply { + u_int16_t weight; + u_int16_t priority; + u_int16_t port; + char *host; +}; + /* ** Parse the buffer, starting at *abuf and of length alen bytes, previously ** obtained from an ares_search call. Put the results in *host, if nonnull. @@ -339,6 +346,8 @@ int ares_parse_ptr_reply(const unsigned char *abuf, int alen, const void *addr, int addrlen, int family, struct hostent **host); int ares_parse_ns_reply(const unsigned char *abuf, int alen, struct hostent **host); +int ares_parse_srv_reply(const unsigned char* abuf, int alen, + struct srv_reply** srv_out, int *nsrvreply); void ares_free_string(void *str); void ares_free_hostent(struct hostent *host); const char *ares_strerror(int code); diff --git a/ares_parse_srv_reply.3 b/ares_parse_srv_reply.3 new file mode 100644 index 0000000..8f3edf4 --- /dev/null +++ b/ares_parse_srv_reply.3 @@ -0,0 +1,78 @@ +.\" +.\" Copyright 1998 by the Massachusetts Institute of Technology. +.\" +.\" Permission to use, copy, modify, and distribute this +.\" software and its documentation for any purpose and without +.\" fee is hereby granted, provided that the above copyright +.\" notice appear in all copies and that both that copyright +.\" notice and this permission notice appear in supporting +.\" documentation, and that the name of M.I.T. not be used in +.\" advertising or publicity pertaining to distribution of the +.\" software without specific, written prior permission. +.\" M.I.T. makes no representations about the suitability of +.\" this software for any purpose. It is provided "as is" +.\" without express or implied warranty. +.\" +.TH ARES_PARSE_SRV_REPLY 3 "4 August 2009" +.SH NAME +ares_parse_srv_reply \- Parse a reply to a DNS query of type SRV into a +struct srv_reply +.SH SYNOPSIS +.nf +.B #include <ares.h> +.PP +.B int ares_parse_srv_reply(const unsigned char* \fIabuf\fP, int \fIalen\fP, +.B struct srv_reply** \fIsrv_out\fP, int *\fInsrvreply\fP); +.fi +.SH DESCRIPTION +The +.B ares_parse_srv_reply +function parses the response to a query of type SRV into a +.I struct srv_reply +The parameters +.I abuf +and +.I alen +give the contents of the response. The result is stored in allocated +memory and a pointer to it stored into the variable pointed to by +.IR srv_out . +The number of responses is stored into the variable pointed to by +.IR nsrvreply . +It is the caller's responsibility to free the resulting +.IR srv_out +structure when it is no longer needed. +.PP +The structure +.I srv_reply +contains the following fields: +.sp +.in +4n +.nf +struct srv_reply { + u_int16_t weight; + u_int16_t priority; + u_int16_t port; + char *host; +}; +.fi +.in +.PP +.SH RETURN VALUES +.B ares_parse_srv_reply +can return any of the following values: +.TP 15 +.B ARES_SUCCESS +The response was successfully parsed. +.TP 15 +.B ARES_EBADRESP +The response was malformatted. +.TP 15 +.B ARES_ENODATA +The response did not contain an answer to the query. +.TP 15 +.B ARES_ENOMEM +Memory was exhausted. +.SH SEE ALSO +.BR ares_query (3) +.SH AUTHOR +Written by Jakub Hrozek <jhrozek@redhat.com>, on behalf of Red Hat, Inc http://www.redhat.com diff --git a/ares_parse_srv_reply.c b/ares_parse_srv_reply.c new file mode 100644 index 0000000..1d1b98d --- /dev/null +++ b/ares_parse_srv_reply.c @@ -0,0 +1,159 @@ +/* Copyright 1998 by the Massachusetts Institute of Technology. + * + * Permission to use, copy, modify, and distribute this + * software and its documentation for any purpose and without + * fee is hereby granted, provided that the above copyright + * notice appear in all copies and that both that copyright + * notice and this permission notice appear in supporting + * documentation, and that the name of M.I.T. not be used in + * advertising or publicity pertaining to distribution of the + * software without specific, written prior permission. + * M.I.T. makes no representations about the suitability of + * this software for any purpose. It is provided "as is" + * without express or implied warranty. + */ + +/* + * ares_parse_srv_reply created by Jakub Hrozek <jhrozek@redhat.com> + * on behalf of Red Hat - http://www.redhat.com + */ + +#include "setup.h" + +#if defined(WIN32) && !defined(WATT32) +#include "nameser.h" +#else +#include <sys/socket.h> +#include <netinet/in.h> +#include <arpa/inet.h> +#include <netdb.h> +#include <arpa/nameser.h> +#ifdef HAVE_ARPA_NAMESER_COMPAT_H +#include <arpa/nameser_compat.h> +#endif +#endif + +#include <stdlib.h> +#include <string.h> +#include "ares.h" +#include "ares_dns.h" +#include "ares_private.h" + +int +ares_parse_srv_reply (const unsigned char *abuf, int alen, + struct srv_reply **srv_out, int *nsrvreply) +{ + unsigned int qdcount, ancount; + const unsigned char *aptr; + int status, i, rr_type, rr_class, rr_len; + long len; + char *hostname = NULL, *rr_name = NULL; + struct srv_reply *srv = NULL; + + /* Set *srv_out to NULL for all failure cases. */ + if (srv_out) + *srv_out = NULL; + /* Same with *nsrvreply. */ + if (nsrvreply) + *nsrvreply = 0; + + /* Give up if abuf doesn't have room for a header. */ + if (alen < HFIXEDSZ) + return ARES_EBADRESP; + + /* Fetch the question and answer count from the header. */ + qdcount = DNS_HEADER_QDCOUNT (abuf); + ancount = DNS_HEADER_ANCOUNT (abuf); + if (qdcount != 1) + return ARES_EBADRESP; + if (ancount == 0) + return ARES_ENODATA; + + /* Expand the name from the question, and skip past the question. */ + aptr = abuf + HFIXEDSZ; + status = ares_expand_name (aptr, abuf, alen, &hostname, &len); + if (status != ARES_SUCCESS) + return status; + + if (aptr + len + QFIXEDSZ > abuf + alen) + { + free (hostname); + return ARES_EBADRESP; + } + aptr += len + QFIXEDSZ; + + /* Allocate srv_reply array; ancount gives an upper bound */ + srv = malloc ((ancount) * sizeof (struct srv_reply)); + if (!srv) + { + free (hostname); + return ARES_ENOMEM; + } + + /* Examine each answer resource record (RR) in turn. */ + for (i = 0; i < (int) ancount; i++) + { + /* Decode the RR up to the data field. */ + status = ares_expand_name (aptr, abuf, alen, &rr_name, &len); + if (status != ARES_SUCCESS) + { + break; + } + aptr += len; + if (aptr + RRFIXEDSZ > abuf + alen) + { + status = ARES_EBADRESP; + break; + } + rr_type = DNS_RR_TYPE (aptr); + rr_class = DNS_RR_CLASS (aptr); + rr_len = DNS_RR_LEN (aptr); + aptr += RRFIXEDSZ; + + /* Check if we are really looking at a SRV record */ + if (rr_class == C_IN && rr_type == T_SRV) + { + /* parse the SRV record itself */ + if (rr_len < 6) + { + status = ARES_EBADRESP; + break; + } + + srv[i].priority = ntohs (*((uint16_t *)aptr)); + aptr += sizeof(uint16_t); + srv[i].weight = ntohs (*((uint16_t *)aptr)); + aptr += sizeof(uint16_t); + srv[i].port = ntohs (*((uint16_t *)aptr)); + aptr += sizeof(uint16_t); + + status = ares_expand_name (aptr, abuf, alen, &srv[i].host, &len); + if (status != ARES_SUCCESS) + break; + + /* Move on to the next record */ + aptr += len; + + /* Don't lose memory in the next iteration */ + free (rr_name); + rr_name = NULL; + } + } + + /* clean up on error */ + if (status != ARES_SUCCESS) + { + free (srv); + free (hostname); + free (rr_name); + return status; + } + + /* everything looks fine, return the data */ + *srv_out = srv; + *nsrvreply = ancount; + + free (hostname); + free (rr_name); + return status; +} |