| Message ID | 1471545435-15543-1-git-send-email-steved@redhat.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
> On Aug 18, 2016, at 2:37 PM, Steve Dickson <SteveD@redhat.com> wrote: > > In domain_from_dns(), when at the hostname is a FQHN > query the DNS server for the _nfsv4idmapdomain TXT > record. If the record exists, use that as the > NFSv4 domain. > > Note, this query will only happen if the domain name > is not set in the /etc/idmapd.conf > > Signed-off-by: Steve Dickson <steved@redhat.com> All three: Reviewed-by: Chuck Lever <chuck.lever@oracle.com> > --- > libnfsidmap.c | 104 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 103 insertions(+), 1 deletion(-) > > diff --git a/libnfsidmap.c b/libnfsidmap.c > index 2db4d13..7b8c0ed 100644 > --- a/libnfsidmap.c > +++ b/libnfsidmap.c > @@ -53,6 +53,10 @@ > #include <stdarg.h> > #include <dlfcn.h> > #include <ctype.h> > +#include <resolv.h> > +#include <arpa/nameser.h> > +#include <arpa/nameser_compat.h> > + > #include "nfsidmap.h" > #include "nfsidmap_internal.h" > #include "cfg.h" > @@ -79,6 +83,11 @@ gid_t nobody_gid = (gid_t)-1; > #define IDMAPD_DEFAULT_DOMAIN "localdomain" > #endif > > +#ifndef NFS4DNSTXTREC > +#define NFS4DNSTXTREC "_nfsv4idmapdomain" > +#endif > + > + > /* Default logging fuction */ > static void default_logger(const char *fmt, ...) > { > @@ -114,6 +123,93 @@ static int id_as_chars(char *name, uid_t *id) > return 1; > } > > +static int dns_txt_query(char *domain, char **nfs4domain) > +{ > + char *txtname = NFS4DNSTXTREC; > + char *msg, *answ, *eom, *mptr; > + int len, status = -1; > + HEADER *hdr; > + > + msg = calloc(1, NS_MAXMSG); > + if (msg == NULL) > + return -1; > + > + answ = calloc(1, NS_MAXMSG); > + if (answ == NULL) { > + free(msg); > + return -1; > + } > + > + if (res_init() < 0) { > + IDMAP_LOG(2, ("libnfsidmap: res_init() failed for %s.%s: %s\n", > + txtname, domain, hstrerror(h_errno))); > + goto freemem; > + } > + len = res_querydomain(txtname, domain, C_IN, T_TXT, msg, NS_MAXMSG); > + if (len < 0) { > + IDMAP_LOG(2, ("libnfsidmap: res_querydomain() failed for %s.%s: %s\n", > + txtname, domain, hstrerror(h_errno))); > + goto freemem; > + } > + hdr = (HEADER *)msg; > + > + /* See if there is an answer */ > + if (ntohs(hdr->ancount) < 1) { > + IDMAP_LOG(2, ("libnfsidmap: No TXT record for %s.%s\n", > + txtname, domain)); > + goto freemem; > + } > + /* find the EndOfMessage */ > + eom = msg + len; > + > + /* skip header */ > + mptr = &msg[HFIXEDSZ]; > + > + /* skip name field in question section */ > + mptr += dn_skipname(mptr, eom) + QFIXEDSZ; > + > + /* read in the question */ > + len = dn_expand(msg, eom, mptr, answ, NS_MAXDNAME); > + if (len < 0) { /* does this really matter?? */ > + IDMAP_LOG(2, ("libnfsidmap: No question section for %s.%s: %s\n", > + txtname, domain, hstrerror(h_errno))); > + goto freemem; > + } > + > + /* > + * Now, dissect the answer section, Note: if there > + * are more than one answer only the first > + * one will be used. > + */ > + > + /* skip passed the name field */ > + mptr += dn_skipname(mptr, eom); > + /* skip pass the type class and ttl fields */ > + mptr += 2 + 2 + 4; > + > + /* make sure there is some data */ > + GETSHORT(len, mptr); > + if (len < 0) { > + IDMAP_LOG(2, ("libnfsidmap: No data in answer for %s.%s\n", > + txtname, domain)); > + goto freemem; > + } > + /* get the lenght field */ > + len = (int)*mptr++; > + /* copy the data */ > + memcpy(answ, mptr, len); > + answ[len] = '\0'; > + > + *nfs4domain = strdup(answ); > + status = 0; > + > +freemem: > + free(msg); > + free(answ); > + > + return (status); > +} > + > static int domain_from_dns(char **domain) > { > struct hostent *he; > @@ -125,7 +221,13 @@ static int domain_from_dns(char **domain) > return -1; > if ((c = strchr(he->h_name, '.')) == NULL || *++c == '\0') > return -1; > - *domain = strdup(c); > + /* > + * Query DNS to see if the _nfsv4idmapdomain TXT record exists > + * If so use it... > + */ > + if (dns_txt_query(c, domain) < 0) > + *domain = strdup(c); > + > return 0; > } > > -- > 2.7.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Chuck Lever -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 08/18/2016 02:37 PM, Steve Dickson wrote: > In domain_from_dns(), when at the hostname is a FQHN > query the DNS server for the _nfsv4idmapdomain TXT > record. If the record exists, use that as the > NFSv4 domain. > > Note, this query will only happen if the domain name > is not set in the /etc/idmapd.conf > > Signed-off-by: Steve Dickson <steved@redhat.com> Committed... steved. > --- > libnfsidmap.c | 104 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 103 insertions(+), 1 deletion(-) > > diff --git a/libnfsidmap.c b/libnfsidmap.c > index 2db4d13..7b8c0ed 100644 > --- a/libnfsidmap.c > +++ b/libnfsidmap.c > @@ -53,6 +53,10 @@ > #include <stdarg.h> > #include <dlfcn.h> > #include <ctype.h> > +#include <resolv.h> > +#include <arpa/nameser.h> > +#include <arpa/nameser_compat.h> > + > #include "nfsidmap.h" > #include "nfsidmap_internal.h" > #include "cfg.h" > @@ -79,6 +83,11 @@ gid_t nobody_gid = (gid_t)-1; > #define IDMAPD_DEFAULT_DOMAIN "localdomain" > #endif > > +#ifndef NFS4DNSTXTREC > +#define NFS4DNSTXTREC "_nfsv4idmapdomain" > +#endif > + > + > /* Default logging fuction */ > static void default_logger(const char *fmt, ...) > { > @@ -114,6 +123,93 @@ static int id_as_chars(char *name, uid_t *id) > return 1; > } > > +static int dns_txt_query(char *domain, char **nfs4domain) > +{ > + char *txtname = NFS4DNSTXTREC; > + char *msg, *answ, *eom, *mptr; > + int len, status = -1; > + HEADER *hdr; > + > + msg = calloc(1, NS_MAXMSG); > + if (msg == NULL) > + return -1; > + > + answ = calloc(1, NS_MAXMSG); > + if (answ == NULL) { > + free(msg); > + return -1; > + } > + > + if (res_init() < 0) { > + IDMAP_LOG(2, ("libnfsidmap: res_init() failed for %s.%s: %s\n", > + txtname, domain, hstrerror(h_errno))); > + goto freemem; > + } > + len = res_querydomain(txtname, domain, C_IN, T_TXT, msg, NS_MAXMSG); > + if (len < 0) { > + IDMAP_LOG(2, ("libnfsidmap: res_querydomain() failed for %s.%s: %s\n", > + txtname, domain, hstrerror(h_errno))); > + goto freemem; > + } > + hdr = (HEADER *)msg; > + > + /* See if there is an answer */ > + if (ntohs(hdr->ancount) < 1) { > + IDMAP_LOG(2, ("libnfsidmap: No TXT record for %s.%s\n", > + txtname, domain)); > + goto freemem; > + } > + /* find the EndOfMessage */ > + eom = msg + len; > + > + /* skip header */ > + mptr = &msg[HFIXEDSZ]; > + > + /* skip name field in question section */ > + mptr += dn_skipname(mptr, eom) + QFIXEDSZ; > + > + /* read in the question */ > + len = dn_expand(msg, eom, mptr, answ, NS_MAXDNAME); > + if (len < 0) { /* does this really matter?? */ > + IDMAP_LOG(2, ("libnfsidmap: No question section for %s.%s: %s\n", > + txtname, domain, hstrerror(h_errno))); > + goto freemem; > + } > + > + /* > + * Now, dissect the answer section, Note: if there > + * are more than one answer only the first > + * one will be used. > + */ > + > + /* skip passed the name field */ > + mptr += dn_skipname(mptr, eom); > + /* skip pass the type class and ttl fields */ > + mptr += 2 + 2 + 4; > + > + /* make sure there is some data */ > + GETSHORT(len, mptr); > + if (len < 0) { > + IDMAP_LOG(2, ("libnfsidmap: No data in answer for %s.%s\n", > + txtname, domain)); > + goto freemem; > + } > + /* get the lenght field */ > + len = (int)*mptr++; > + /* copy the data */ > + memcpy(answ, mptr, len); > + answ[len] = '\0'; > + > + *nfs4domain = strdup(answ); > + status = 0; > + > +freemem: > + free(msg); > + free(answ); > + > + return (status); > +} > + > static int domain_from_dns(char **domain) > { > struct hostent *he; > @@ -125,7 +221,13 @@ static int domain_from_dns(char **domain) > return -1; > if ((c = strchr(he->h_name, '.')) == NULL || *++c == '\0') > return -1; > - *domain = strdup(c); > + /* > + * Query DNS to see if the _nfsv4idmapdomain TXT record exists > + * If so use it... > + */ > + if (dns_txt_query(c, domain) < 0) > + *domain = strdup(c); > + > return 0; > } > > -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/libnfsidmap.c b/libnfsidmap.c index 2db4d13..7b8c0ed 100644 --- a/libnfsidmap.c +++ b/libnfsidmap.c @@ -53,6 +53,10 @@ #include <stdarg.h> #include <dlfcn.h> #include <ctype.h> +#include <resolv.h> +#include <arpa/nameser.h> +#include <arpa/nameser_compat.h> + #include "nfsidmap.h" #include "nfsidmap_internal.h" #include "cfg.h" @@ -79,6 +83,11 @@ gid_t nobody_gid = (gid_t)-1; #define IDMAPD_DEFAULT_DOMAIN "localdomain" #endif +#ifndef NFS4DNSTXTREC +#define NFS4DNSTXTREC "_nfsv4idmapdomain" +#endif + + /* Default logging fuction */ static void default_logger(const char *fmt, ...) { @@ -114,6 +123,93 @@ static int id_as_chars(char *name, uid_t *id) return 1; } +static int dns_txt_query(char *domain, char **nfs4domain) +{ + char *txtname = NFS4DNSTXTREC; + char *msg, *answ, *eom, *mptr; + int len, status = -1; + HEADER *hdr; + + msg = calloc(1, NS_MAXMSG); + if (msg == NULL) + return -1; + + answ = calloc(1, NS_MAXMSG); + if (answ == NULL) { + free(msg); + return -1; + } + + if (res_init() < 0) { + IDMAP_LOG(2, ("libnfsidmap: res_init() failed for %s.%s: %s\n", + txtname, domain, hstrerror(h_errno))); + goto freemem; + } + len = res_querydomain(txtname, domain, C_IN, T_TXT, msg, NS_MAXMSG); + if (len < 0) { + IDMAP_LOG(2, ("libnfsidmap: res_querydomain() failed for %s.%s: %s\n", + txtname, domain, hstrerror(h_errno))); + goto freemem; + } + hdr = (HEADER *)msg; + + /* See if there is an answer */ + if (ntohs(hdr->ancount) < 1) { + IDMAP_LOG(2, ("libnfsidmap: No TXT record for %s.%s\n", + txtname, domain)); + goto freemem; + } + /* find the EndOfMessage */ + eom = msg + len; + + /* skip header */ + mptr = &msg[HFIXEDSZ]; + + /* skip name field in question section */ + mptr += dn_skipname(mptr, eom) + QFIXEDSZ; + + /* read in the question */ + len = dn_expand(msg, eom, mptr, answ, NS_MAXDNAME); + if (len < 0) { /* does this really matter?? */ + IDMAP_LOG(2, ("libnfsidmap: No question section for %s.%s: %s\n", + txtname, domain, hstrerror(h_errno))); + goto freemem; + } + + /* + * Now, dissect the answer section, Note: if there + * are more than one answer only the first + * one will be used. + */ + + /* skip passed the name field */ + mptr += dn_skipname(mptr, eom); + /* skip pass the type class and ttl fields */ + mptr += 2 + 2 + 4; + + /* make sure there is some data */ + GETSHORT(len, mptr); + if (len < 0) { + IDMAP_LOG(2, ("libnfsidmap: No data in answer for %s.%s\n", + txtname, domain)); + goto freemem; + } + /* get the lenght field */ + len = (int)*mptr++; + /* copy the data */ + memcpy(answ, mptr, len); + answ[len] = '\0'; + + *nfs4domain = strdup(answ); + status = 0; + +freemem: + free(msg); + free(answ); + + return (status); +} + static int domain_from_dns(char **domain) { struct hostent *he; @@ -125,7 +221,13 @@ static int domain_from_dns(char **domain) return -1; if ((c = strchr(he->h_name, '.')) == NULL || *++c == '\0') return -1; - *domain = strdup(c); + /* + * Query DNS to see if the _nfsv4idmapdomain TXT record exists + * If so use it... + */ + if (dns_txt_query(c, domain) < 0) + *domain = strdup(c); + return 0; }
In domain_from_dns(), when at the hostname is a FQHN query the DNS server for the _nfsv4idmapdomain TXT record. If the record exists, use that as the NFSv4 domain. Note, this query will only happen if the domain name is not set in the /etc/idmapd.conf Signed-off-by: Steve Dickson <steved@redhat.com> --- libnfsidmap.c | 104 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 103 insertions(+), 1 deletion(-)