Make gateway objects also detect routes with missing RTF_GATEWAY flag

This was a bug, not a feature. From the FreeBSD manpage rtentry(9):

| Vt struct sockaddr *rt_gateway;
|
| The "target" of the route, which can either represent a destination in
| its own right (some protocols will put a link-layer address here), or
| some intermediate stop on the way to that destination (if the
| RTF_GATEWAY flag is set).

So for a default route with "dest" and "mask" both zero, either
RTF_GATEWAY is present, or "gate" is zero.

diff --git a/ChangeLog b/ChangeLog
index a87fc90..297b821 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,6 @@
+2008-12-17
+       * Make gateway objects also detect routes with missing RTF_GATEWAY flag
+
 2008-12-15
        * Have a maximum width for all variable length mpd vars
 

diff --git a/src/linux.c b/src/linux.c
index 57b6f59..e1dbfe1 100644 (file)
--- a/src/linux.c
+++ b/src/linux.c
@@ -272,6 +272,10 @@ void update_gateway_info_failure(const char *reason)
        info.gw_info.ip = strndup("failed", text_buffer_size);
 }
 
+
+/* Iface Destination Gateway Flags RefCnt Use Metric Mask MTU Window IRTT */
+#define RT_ENTRY_FORMAT "%63s %lx %lx %x %*d %*d %*d %lx %*d %*d %*d\n"
+
 void update_gateway_info(void)
 {
        FILE *fp;
@@ -279,7 +283,6 @@ void update_gateway_info(void)
        char iface[64];
        unsigned long dest, gate, mask;
        unsigned int flags;
-       short ref, use, metric, mtu, win, irtt;
 
        struct gateway_info *gw_info = &info.gw_info;
 
@@ -289,27 +292,22 @@ void update_gateway_info(void)
 
        if ((fp = fopen("/proc/net/route", "r")) == NULL) {
                update_gateway_info_failure("fopen()");
-               return;
-       }
-       if (fscanf(fp, "%*[^\n]\n") == EOF) {
-               //NULL because a empty table is not a error
-               update_gateway_info_failure(NULL);
-               fclose(fp);
                return;
        }
+
+       /* skip over the table header line, which is always present */
+       fscanf(fp, "%*[^\n]\n");
+
        while (!feof(fp)) {
-               // Iface Destination Gateway Flags RefCnt Use Metric Mask MTU Window IRTT
-               if(fscanf(fp, "%63s %lx %lx %x %hd %hd %hd %lx %hd %hd %hd\n",
-                                       iface, &dest, &gate, &flags, &ref, &use,
-                                       &metric, &mask, &mtu, &win, &irtt) != 11) {
+               if(fscanf(fp, RT_ENTRY_FORMAT,
+                         iface, &dest, &gate, &flags, &mask) != 5) {
                        update_gateway_info_failure("fscanf()");
-                       fclose(fp);
-                       return;
+                       break;
                }
-               if (flags & RTF_GATEWAY && dest == 0 && mask == 0) {
+               if (!(dest || mask) && ((flags & RTF_GATEWAY) || !gate) ) {
                        gw_info->count++;
                        SAVE_SET_STRING(gw_info->iface, iface)
-                               ina.s_addr = gate;
+                       ina.s_addr = gate;
                        SAVE_SET_STRING(gw_info->ip, inet_ntoa(ina))
                }
        }