* implement a "minimal" mode

* add configure option to allow building of nss-mdns without legacy mDNS queries


git-svn-id: file:///home/lennart/svn/public/nss-mdns/trunk@91 0ee8848e-81ea-0310-a63a-f631d1a40d77

6 files changed, 252 insertions, 81 deletions

diff --git a/configure.ac b/configure.ac
index 1b7034a..cafaa15 100644
--- a/configure.ac
+++ b/configure.ac
@@ -39,6 +39,32 @@ AC_PROG_INSTALL
 AC_PROG_LN_S
 AC_PROG_MAKE_SET
 
+test_gcc_flag() {
+    AC_LANG_CONFTEST([int main() {}])
+    $CC -c conftest.c $CFLAGS $@ > /dev/null 2> /dev/null
+    ret=$?
+    rm -f conftest.o
+    return $ret
+}
+
+# If using GCC specify some additional parameters
+if test "x$GCC" = "xyes" ; then
+
+    # We use gnu99 instead of c99 because many have interpreted the standard
+    # in a way that int64_t isn't defined on non-64 bit platforms.
+    DESIRED_FLAGS="-std=gnu99 -Wall -W -Wextra -pedantic -pipe -Wformat -Wold-style-definition -Wdeclaration-after-statement -Wfloat-equal -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wredundant-decls -Wmissing-noreturn -Wshadow -Wendif-labels -Wpointer-arith -Wbad-function-cast -Wcast-qual -Wcast-align -Wwrite-strings -Winline -Wno-unused-parameter"
+
+    for flag in $DESIRED_FLAGS ; do
+        AC_MSG_CHECKING([whether $CC accepts $flag])
+        if test_gcc_flag $flag ; then 
+           CFLAGS="$CFLAGS $flag"
+           AC_MSG_RESULT([yes])
+        else
+           AC_MSG_RESULT([no])
+        fi
+    done 
+fi
+
 # libtool stuff
 AC_DISABLE_STATIC
 AC_PROG_LIBTOOL
@@ -79,14 +105,23 @@ if test x$lynx = xyes ; then
    AC_CHECK_PROG(have_lynx, lynx, yes, no)
 
    if test x$have_lynx = xno ; then
-     AC_MSG_WARN([*** lynx not found, plain text README will not be built ***])
+     lynx=no
+     AC_CHECK_PROG(have_links, links, yes, no)
+     if test x$have_links = xno ; then
+       AC_MSG_WARN([*** neither lynx nor links found, plain text README will not be built ***])
+     else
+       links=yes
+     fi
    fi
 fi
 
 AM_CONDITIONAL([USE_LYNX], [test "x$lynx" = xyes])
+AM_CONDITIONAL([USE_LINKS], [test "x$links" = xyes])
+
+### Enable avahi support?
 
 AC_ARG_ENABLE(avahi,
-        AC_HELP_STRING([--enable-avahi],[use Avahi (default=yes)]),
+        AC_HELP_STRING([--enable-avahi],[Enable lookups with Avahi (default=yes)]),
         [case "${enableval}" in
                 yes) ENABLE_AVAHI=yes ;;
                 no)  ENABLE_AVAHI=no ;;
@@ -94,13 +129,32 @@ AC_ARG_ENABLE(avahi,
         esac],
         [ENABLE_AVAHI=yes]) dnl Default value
 
-
 AM_CONDITIONAL([ENABLE_AVAHI], [test "x$ENABLE_AVAHI" = "xyes"])
 
 if test "x$ENABLE_AVAHI" = "xyes" ; then
    AC_DEFINE(ENABLE_AVAHI, [1], [Try to make use of a running avahi mDNS server before resolving on our own behalf])
 fi
 
+### Enable legacy support?
+
+AC_ARG_ENABLE(legacy,
+        AC_HELP_STRING([--enable-legacy],[Enable legacy lookups when Avahi isn't available (default=yes)]),
+        [case "${enableval}" in
+                yes) ENABLE_LEGACY=yes ;;
+                no)  ENABLE_LEGACY=no ;;
+                *) AC_MSG_ERROR(bad value ${enableval} for --enable-legacy) ;;
+        esac],
+        [ENABLE_LEGACY=yes]) dnl Default value
+
+if test "x$ENABLE_AVAHI" = "xno" -a "x$ENABLE_LEGACY" = "xno"; then
+	AC_MSG_ERROR(Can't disable legacy lookups if Avahi support is disabled)
+fi
+
+if test "x$ENABLE_LEGACY" = "xyes" ; then
+   AC_DEFINE(ENABLE_LEGACY, [1], [Enable legacy lookups when Avahi isn't available])
+fi
+
+AM_CONDITIONAL([ENABLE_LEGACY], [test "x$ENABLE_LEGACY" = "xyes"])
 
 AC_CONFIG_FILES([Makefile src/Makefile doc/Makefile doc/README.html ])
 AC_OUTPUT
diff --git a/doc/Makefile.am b/doc/Makefile.am
index 752b2d6..a122244 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -29,6 +29,13 @@ README: README.html
 CLEANFILES += README
 endif
 
+if USE_LINKS
+README: README.html
+	links -dump $^ | sed 's,file://localhost/.*/doc/README.html,README,' > $@
+
+CLEANFILES += README
+endif
+
 tidy: README.html
 	tidy -qe < README.html ; true
 
diff --git a/src/Makefile.am b/src/Makefile.am
index e9d5f91..7633c37 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -27,38 +27,85 @@ AM_CFLAGS = \
 # This cool debug trap works on i386/gcc only
 AM_CFLAGS+='-DDEBUG_TRAP=__asm__("int $$3")'
 
-noinst_PROGRAMS = nss-test mdns-test
-lib_LTLIBRARIES = libnss_mdns.la libnss_mdns4.la libnss_mdns6.la
+lib_LTLIBRARIES= \
+	libnss_mdns.la \
+	libnss_mdns4.la \
+	libnss_mdns6.la \
+	libnss_mdns_minimal.la \
+	libnss_mdns4_minimal.la \
+	libnss_mdns6_minimal.la
 
-mdns_test_SOURCES = query.c dns.c util.c mdns-test.c \
-		    query.h dns.h util.h
+noinst_PROGRAMS= \
+	nss-test
 
-nss_test_SOURCES = nss-test.c
+libnss_mdns_la_SOURCES= \
+	nss.c \
+	util.c util.h
 
-libnss_mdns_la_SOURCES = query.c dns.c util.c nss.c query.h dns.h util.h
 libnss_mdns_la_CFLAGS=$(AM_CFLAGS) 
 libnss_mdns_la_LDFLAGS=-avoid-version -module -export-dynamic -shrext .so.2
 
 if ENABLE_AVAHI
+libnss_mdns_la_SOURCES += \
+	avahi.c	avahi.h
+
 noinst_PROGRAMS += avahi-test
-avahi_test_SOURCES = avahi.c util.c avahi.h util.h avahi-test.c
-libnss_mdns_la_SOURCES += avahi.c avahi.h
 endif
 
+if ENABLE_LEGACY
+libnss_mdns_la_SOURCES += \
+	query.c query.h \
+	dns.c dns.h
+
+noinst_PROGRAMS += mdns-test
+endif
+
+libnss_mdns_minimal_la_SOURCES=$(libnss_mdns_la_SOURCES)
+libnss_mdns_minimal_la_CFLAGS=$(libnss_mdns_la_CFLAGS) -DMDNS_MINIMAL
+libnss_mdns_minimal_la_LDFLAGS=$(libnss_mdns_la_LDFLAGS)
+
 libnss_mdns4_la_SOURCES=$(libnss_mdns_la_SOURCES)
 libnss_mdns4_la_CFLAGS=$(libnss_mdns_la_CFLAGS) -DNSS_IPV4_ONLY=1
 libnss_mdns4_la_LDFLAGS=$(libnss_mdns_la_LDFLAGS)
 
+libnss_mdns4_minimal_la_SOURCES=$(libnss_mdns_la_SOURCES)
+libnss_mdns4_minimal_la_CFLAGS=$(libnss_mdns_la_CFLAGS) -DNSS_IPV4_ONLY=1 -DMDNS_MINIMAL
+libnss_mdns4_minimal_la_LDFLAGS=$(libnss_mdns_la_LDFLAGS)
+
 libnss_mdns6_la_SOURCES=$(libnss_mdns_la_SOURCES)
 libnss_mdns6_la_CFLAGS=$(libnss_mdns_la_CFLAGS) -DNSS_IPV6_ONLY=1
 libnss_mdns6_la_LDFLAGS=$(libnss_mdns_la_LDFLAGS)
 
+libnss_mdns6_minimal_la_SOURCES=$(libnss_mdns_la_SOURCES)
+libnss_mdns6_minimal_la_CFLAGS=$(libnss_mdns_la_CFLAGS) -DNSS_IPV6_ONLY=1 -DMDNS_MINIMAL
+libnss_mdns6_minimal_la_LDFLAGS=$(libnss_mdns_la_LDFLAGS)
+
+avahi_test_SOURCES = \
+	avahi.c avahi.h \
+	util.c util.h \
+	avahi-test.c
+
+mdns_test_SOURCES = \
+	query.c query.h \
+	dns.c dns.h \
+	util.c util.h \
+	mdns-test.c
+
+nss_test_SOURCES = \
+	nss-test.c
+
 install-exec-hook:
 	rm -f $(DESTDIR)$(libdir)/libnss_mdns.la 
+	rm -f $(DESTDIR)$(libdir)/libnss_mdns_minimal.la 
 	rm -f $(DESTDIR)$(libdir)/libnss_mdns4.la 
+	rm -f $(DESTDIR)$(libdir)/libnss_mdns4_minimal.la 
 	rm -f $(DESTDIR)$(libdir)/libnss_mdns6.la 
+	rm -f $(DESTDIR)$(libdir)/libnss_mdns6_minimal.la 
 
 uninstall-hook:
 	rm -f $(DESTDIR)$(libdir)/libnss_mdns.so.2 
+	rm -f $(DESTDIR)$(libdir)/libnss_mdns_minimal.so.2 
 	rm -f $(DESTDIR)$(libdir)/libnss_mdns4.so.2 
-	rm -f $(DESTDIR)$(libdir)/libnss_mdns6.so.2
+	rm -f $(DESTDIR)$(libdir)/libnss_mdns4_minimal.so.2 
+	rm -f $(DESTDIR)$(libdir)/libnss_mdns6.so.2 
+	rm -f $(DESTDIR)$(libdir)/libnss_mdns6_minimal.so.2 
diff --git a/src/nss.c b/src/nss.c
index 5b5579a..50e710c 100644
--- a/src/nss.c
+++ b/src/nss.c
@@ -39,19 +39,32 @@
 #include "avahi.h"
 #endif
 
-#define MAX_ENTRIES 16
-
-#ifdef NSS_IPV4_ONLY
+#if defined(NSS_IPV4_ONLY) && ! defined(MDNS_MINIMAL)
 #define _nss_mdns_gethostbyname2_r _nss_mdns4_gethostbyname2_r
-#define _nss_mdns_gethostbyname_r _nss_mdns4_gethostbyname_r
-#define _nss_mdns_gethostbyaddr_r _nss_mdns4_gethostbyaddr_r
-#elif NSS_IPV6_ONLY
+#define _nss_mdns_gethostbyname_r  _nss_mdns4_gethostbyname_r
+#define _nss_mdns_gethostbyaddr_r  _nss_mdns4_gethostbyaddr_r
+#elif defined(NSS_IPV4_ONLY) && defined(MDNS_MINIMAL)
+#define _nss_mdns_gethostbyname2_r _nss_mdns4_minimal_gethostbyname2_r
+#define _nss_mdns_gethostbyname_r  _nss_mdns4_minimal_gethostbyname_r
+#define _nss_mdns_gethostbyaddr_r  _nss_mdns4_minimal_gethostbyaddr_r
+#elif defined(NSS_IPV6_ONLY) && ! defined(MDNS_MINIMAL)
 #define _nss_mdns_gethostbyname2_r _nss_mdns6_gethostbyname2_r
-#define _nss_mdns_gethostbyname_r _nss_mdns6_gethostbyname_r
-#define _nss_mdns_gethostbyaddr_r _nss_mdns6_gethostbyaddr_r
+#define _nss_mdns_gethostbyname_r  _nss_mdns6_gethostbyname_r
+#define _nss_mdns_gethostbyaddr_r  _nss_mdns6_gethostbyaddr_r
+#elif defined(NSS_IPV6_ONLY) && defined(MDNS_MINIMAL)
+#define _nss_mdns_gethostbyname2_r _nss_mdns6_minimal_gethostbyname2_r
+#define _nss_mdns_gethostbyname_r  _nss_mdns6_minimal_gethostbyname_r
+#define _nss_mdns_gethostbyaddr_r  _nss_mdns6_minimal_gethostbyaddr_r
+#elif defined(MDNS_MINIMAL)
+#define _nss_mdns_gethostbyname2_r _nss_mdns_minimal_gethostbyname2_r
+#define _nss_mdns_gethostbyname_r  _nss_mdns_minimal_gethostbyname_r
+#define _nss_mdns_gethostbyaddr_r  _nss_mdns_minimal_gethostbyaddr_r
 #endif
 
-/* the resolv conf page states that they only support 6 domains */
+/* Maximum number of entries to return */
+#define MAX_ENTRIES 16
+
+/* The resolv.conf page states that they only support 6 domains */
 #define MAX_SEARCH_DOMAINS 6
 
 struct userdata {
@@ -113,44 +126,50 @@ static int ends_with(const char *name, const char* suffix) {
 }
 
 static int verify_name_allowed(const char *name) {
+#ifndef MDNS_MINIMAL
     FILE *f;
-    int valid = 0;
+#endif
     
     assert(name);
 
-    if (!(f = fopen(MDNS_ALLOW_FILE, "r")))
-        return ends_with(name, ".local") || ends_with(name, ".local."); 
-
-    while (!feof(f)) {
-        char ln[128], ln2[128], *t;
+#ifndef MDNS_MINIMAL
+    if ((f = fopen(MDNS_ALLOW_FILE, "r"))) {
+        int valid = 0;
         
-        if (!fgets(ln, sizeof(ln), f))
-            break;
-
-        ln[strcspn(ln, "#\t\n\r ")] = 0;
-
-        if (ln[0] == 0)
-            continue;
-
-        if (strcmp(ln, "*") == 0) {
-            valid = 1;
-            break;
-        }
-
-        if (ln[0] != '.')
-            snprintf(t = ln2, sizeof(ln2), ".%s", ln);
-        else
-            t = ln;
-
-        if (ends_with(name, t)) {
-            valid = 1;
-            break;
+        
+        while (!feof(f)) {
+            char ln[128], ln2[128], *t;
+            
+            if (!fgets(ln, sizeof(ln), f))
+                break;
+            
+            ln[strcspn(ln, "#\t\n\r ")] = 0;
+            
+            if (ln[0] == 0)
+                continue;
+            
+            if (strcmp(ln, "*") == 0) {
+                valid = 1;
+                break;
+            }
+            
+            if (ln[0] != '.')
+                snprintf(t = ln2, sizeof(ln2), ".%s", ln);
+            else
+                t = ln;
+            
+            if (ends_with(name, t)) {
+                valid = 1;
+                break;
+            }
         }
+        
+        fclose(f);
+        return valid;
     }
+#endif
 
-    fclose(f);
-
-    return valid;
+    return ends_with(name, ".local") || ends_with(name, ".local."); 
 }
 
 static char **alloc_domains(unsigned ndomains) {
@@ -268,7 +287,7 @@ enum nss_status _nss_mdns_gethostbyname2_r(
 
     struct userdata u;
     enum nss_status status = NSS_STATUS_UNAVAIL;
-    int fd = -1, i;
+    int i;
     size_t address_length, l, idx, astart;
     void (*ipv4_func)(const ipv4_address_t *ipv4, void *userdata);
     void (*ipv6_func)(const ipv6_address_t *ipv6, void *userdata);
@@ -279,6 +298,10 @@ enum nss_status _nss_mdns_gethostbyname2_r(
     uint8_t data[128];
 #endif
 
+#ifdef ENABLE_LEGACY
+    int fd = -1;
+#endif
+
 /*     DEBUG_TRAP; */
 
 #ifdef NSS_IPV4_ONLY
@@ -381,11 +404,14 @@ enum nss_status _nss_mdns_gethostbyname2_r(
 	    free_domains(domains);
 	}
     }
+#endif
 
-
-    if (u.count == 0 && !avahi_works) {
+#if defined(ENABLE_LEGACY) && defined(ENABLE_AVAHI)
+    if (u.count == 0 && !avahi_works) 
 #endif
 
+#if defined(ENABLE_LEGACY)
+    {
         if ((fd = mdns_open_socket()) < 0) {
             *errnop = errno;
             *h_errnop = NO_RECOVERY;
@@ -432,14 +458,13 @@ enum nss_status _nss_mdns_gethostbyname2_r(
                 free_domains(domains);
 	    }
         }
-
-#ifdef ENABLE_AVAHI
     }
 #endif
 
     if (u.count == 0) {
         *errnop = ETIMEDOUT;
         *h_errnop = HOST_NOT_FOUND;
+        status = NSS_STATUS_NOTFOUND;
         goto finish;
     }
     
@@ -483,8 +508,10 @@ enum nss_status _nss_mdns_gethostbyname2_r(
     status = NSS_STATUS_SUCCESS;
     
 finish:
+#ifdef ENABLE_LEGACY
     if (fd >= 0)
         close(fd);
+#endif
     
     return status;
 }
@@ -523,18 +550,23 @@ enum nss_status _nss_mdns_gethostbyaddr_r(
     
     struct userdata u;
     enum nss_status status = NSS_STATUS_UNAVAIL;
-    int fd = -1, r;
+    int r;
     size_t address_length, idx, astart;
+    
 #ifdef ENABLE_AVAHI
     char t[256];
 #endif
+#ifdef ENABLE_LEGACY
+    int fd = -1;
+#endif
 
     *errnop = EINVAL;
     *h_errnop = NO_RECOVERY;
 
     u.count = 0;
     u.data_len = 0;
-    
+
+    /* Check for address types */
     address_length = af == AF_INET ? sizeof(ipv4_address_t) : sizeof(ipv6_address_t);
 
     if (len != (int) address_length ||
@@ -551,6 +583,7 @@ enum nss_status _nss_mdns_gethostbyaddr_r(
         goto finish;
     }
 
+    /* Check for buffer space */
     if (buflen <
         sizeof(char*)+      /* alias names */
         address_length) {   /* address */
@@ -562,27 +595,45 @@ enum nss_status _nss_mdns_gethostbyaddr_r(
         goto finish;
     }
 
-#ifdef ENABLE_AVAHI
+#ifdef MDNS_MINIMAL
+    /* Only query for 169.254.0.0/16 IPv4 in minimal mode */
+    if ((af == AF_INET && ((*(uint32_t*)  &addr) & 0xFFFF0000UL) != 0xA9FE0000UL) ||
+        (af == AF_INET6 && !(((uint8_t*) &addr)[0] == 0xFE && (((uint8_t*) &addr)[1] >> 6) == 2))) {
+
+        *errnop = EINVAL;
+        *h_errnop = NO_RECOVERY;
 
+        goto finish;
+    }
+#endif
+    
+#ifdef ENABLE_AVAHI
+    /* Lookup using Avahi */
     if ((r = avahi_resolve_address(af, addr, t, sizeof(t))) == 0) {
         name_callback(t, &u);
     } else if (r > 0) {
         *errnop = ETIMEDOUT;
         *h_errnop = HOST_NOT_FOUND;
+        status = NSS_STATUS_NOTFOUND;
         goto finish;
-    }
-
-#endif 
-
-    if (u.count == 0) {
+    } 
+#endif
 
+#if defined(ENABLE_AVAHI) && defined(ENABLE_LEGACY)
+    else
+#endif
+    
+#ifdef ENABLE_LEGACY
+     /* Lookup using legacy mDNS queries */   
+     {
         if ((fd = mdns_open_socket()) < 0) {
-            
             *errnop = errno;
             *h_errnop = NO_RECOVERY;
             goto finish;
         }
-        
+
+	r = -1;
+
 #if ! defined(NSS_IPV6_ONLY) && ! defined(NSS_IPV4_ONLY)
         if (af == AF_INET)
 #endif
@@ -595,13 +646,14 @@ enum nss_status _nss_mdns_gethostbyaddr_r(
 #ifndef NSS_IPV4_ONLY        
             r = mdns_query_ipv6(fd, (const ipv6_address_t*) addr, name_callback, &u);
 #endif
-        
         if (r < 0) {
             *errnop = ETIMEDOUT;
             *h_errnop = HOST_NOT_FOUND;
+            status = NSS_STATUS_NOTFOUND;
             goto finish;
         }
     }
+#endif /* ENABLE_LEGACY */
 
     /* Alias names */
     *((char**) buffer) = NULL;
@@ -642,8 +694,10 @@ enum nss_status _nss_mdns_gethostbyaddr_r(
     status = NSS_STATUS_SUCCESS;
     
 finish:
+#ifdef ENABLE_LEGACY
     if (fd >= 0)
         close(fd);
+#endif
     
     return status;
 }
diff --git a/src/util.c b/src/util.c
index bf37711..1d0cd90 100644
--- a/src/util.c
+++ b/src/util.c
@@ -31,6 +31,8 @@
 
 #include "util.h"
 
+#ifdef ENABLE_LEGACY
+
 /* Calculate the difference between the two specfified timeval
  * timestamsps. */
 usec_t timeval_diff(const struct timeval *a, const struct timeval *b) {
@@ -102,19 +104,6 @@ void timeval_add(struct timeval *tv, usec_t v) {
     }
 }
 
-int set_cloexec(int fd) {
-    int n;
-    assert(fd >= 0);
-    
-    if ((n = fcntl(fd, F_GETFD)) < 0)
-        return -1;
-
-    if (n & FD_CLOEXEC)
-        return 0;
-
-    return fcntl(fd, F_SETFD, n|FD_CLOEXEC);
-}
-
 int set_nonblock(int fd) {
     int n;
     assert(fd >= 0);
@@ -203,3 +192,18 @@ int wait_for_read(int fd, struct timeval *end) {
     }
 }
 
+#endif
+
+int set_cloexec(int fd) {
+    int n;
+    assert(fd >= 0);
+    
+    if ((n = fcntl(fd, F_GETFD)) < 0)
+        return -1;
+
+    if (n & FD_CLOEXEC)
+        return 0;
+
+    return fcntl(fd, F_SETFD, n|FD_CLOEXEC);
+}
+
diff --git a/src/util.h b/src/util.h
index b227ce0..e2334ad 100644
--- a/src/util.h
+++ b/src/util.h
@@ -26,6 +26,7 @@
 #include <time.h>
 #include <inttypes.h>
 
+#ifdef ENABLE_LEGACY
 typedef uint64_t usec_t;
 
 usec_t timeval_diff(const struct timeval *a, const struct timeval *b);
@@ -34,9 +35,13 @@ usec_t timeval_age(const struct timeval *tv);
 void timeval_add(struct timeval *tv, usec_t v);
 
 int set_nonblock(int fd);
-int set_cloexec(int fd);
 
 int wait_for_write(int fd, struct timeval *end);
 int wait_for_read(int fd, struct timeval *end);
 
 #endif
+
+int set_cloexec(int fd);
+
+
+#endif