vlserver: do not perform ChangeAddr on mh entries, except for removal

Fix a long standing bug in the ChangeAddr RPC which damages the vldb,

When vos changeaddr is run with -oldaddr and -newaddr, and the -oldaddr
is present in an multi-homed entry, instead of changing the address in
the mh entry, the server slot is "downgraded" to a single homed entry
and the mh entry is orphaned in the vldb.

Instead, if the -oldaddr is in a multi-home entry, refuse to change the
address with a VL entry not found error and log the event.

Multi-homed addresses can be changed manually using the vos setaddrs
command which calls the RegisterAddrs() RPC.

Reviewed-on: http://gerrit.openafs.org/11639
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Reviewed-by: Daria Brashear <shadow@your-file-system.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
(cherry picked from commit 1cc77cd43732cca1c617db329a71693903d2b699)

Change-Id: I14a77317d582dd1cb8490e643b8fdfc86f4942c0
Reviewed-on: https://gerrit.openafs.org/12089
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>

diff --git a/src/vlserver/vlprocs.c b/src/vlserver/vlprocs.c
index cc3af1cfcd31166b3e5efd54bcb9ebe85cc78d9e..6f8be32f6a886d1a8eb0dd5d0a2aaa03f3e72e64 100644 (file)
--- a/src/vlserver/vlprocs.c
+++ b/src/vlserver/vlprocs.c
@@ -3326,7 +3326,7 @@ ChangeIPAddr(struct vl_ctx *ctx, afs_uint32 ipaddr1, afs_uint32 ipaddr2)
     int i, j;
     afs_int32 code;
     struct extentaddr *exp = NULL;
-    int base = 0;
+    int base = -1;
     int index, mhidx;
     afsUUID tuuid;
     afs_int32 blockindex, count;
@@ -3336,7 +3336,7 @@ ChangeIPAddr(struct vl_ctx *ctx, afs_uint32 ipaddr1, afs_uint32 ipaddr2)
     char addrbuf1[256];
     char addrbuf2[256];
 
-    /* Don't let addr change to 256.*.*.* : Causes internal error below */
+    /* Don't let addr change to 255.*.*.* : Causes internal error below */
     if ((ipaddr2 & 0xff000000) == 0xff000000)
        return (VL_BADSERVER);
 
@@ -3352,30 +3352,35 @@ ChangeIPAddr(struct vl_ctx *ctx, afs_uint32 ipaddr1, afs_uint32 ipaddr2)
     }
 
     for (i = 0; i <= MAXSERVERID; i++) {
+       struct extentaddr *texp = NULL;
+       int tbase;
+
        if ((ctx->hostaddress[i] & 0xff000000) == 0xff000000) {
-           base = (ctx->hostaddress[i] >> 16) & 0xff;
+           tbase = (ctx->hostaddress[i] >> 16) & 0xff;
            index = ctx->hostaddress[i] & 0x0000ffff;
-           if ((base >= VL_MAX_ADDREXTBLKS) || (index >= VL_MHSRV_PERBLK)) {
+           if ((tbase >= VL_MAX_ADDREXTBLKS) || (index >= VL_MHSRV_PERBLK)) {
                VLog(0,
                     ("Internal error: Multihome extent addr is too large. Base %d index %d\n",
-                     base, index));
+                     tbase, index));
                return -1;      /* EINVAL */
            }
-
-           exp = &ctx->ex_addr[base][index];
+           texp = &ctx->ex_addr[tbase][index];
            for (mhidx = 0; mhidx < VL_MAXIPADDRS_PERMH; mhidx++) {
-               if (!exp->ex_addrs[mhidx])
+               if (!texp->ex_addrs[mhidx])
                    continue;
-               if (ntohl(exp->ex_addrs[mhidx]) == ipaddr1) {
+               if (ntohl(texp->ex_addrs[mhidx]) == ipaddr1) {
                    ipaddr1_id = i;
+                   exp = texp;
+                   base = tbase;
                }
-               if (ipaddr2 != 0 && ntohl(exp->ex_addrs[mhidx]) == ipaddr2) {
+               if (ipaddr2 != 0 && ntohl(texp->ex_addrs[mhidx]) == ipaddr2) {
                    ipaddr2_id = i;
                }
            }
        } else {
            if (ctx->hostaddress[i] == ipaddr1) {
                exp = NULL;
+               base = -1;
                ipaddr1_id = i;
            }
            if (ipaddr2 != 0 && ctx->hostaddress[i] == ipaddr2) {
@@ -3425,6 +3430,15 @@ ChangeIPAddr(struct vl_ctx *ctx, afs_uint32 ipaddr1, afs_uint32 ipaddr2)
                }
            }
        }
+    } else if (exp) {
+       /* Do not allow changing addresses in multi-homed entries.
+          Older versions of this RPC would silently "downgrade" mh entries
+          to single-homed entries and orphan the mh enties. */
+       addrbuf1[0] = '\0';
+       append_addr(addrbuf1, ipaddr1, sizeof(addrbuf1));
+       VLog(0, ("Refusing to change address %s in multi-homed entry; "
+                "use RegisterAddrs instead.\n", addrbuf1));
+       return VL_NOENT;        /* single-homed entry not found */
     }
 
     /* Log a message saying we are changing/removing an IP address */
@@ -3446,10 +3460,10 @@ ChangeIPAddr(struct vl_ctx *ctx, afs_uint32 ipaddr1, afs_uint32 ipaddr2)
     if (ipaddr2) {
        append_addr(addrbuf2, ipaddr2, sizeof(addrbuf2));
     }
-    VLog(0, ("      entry %d: [%s] -> [%s]\n", i, addrbuf1, addrbuf2));
+    VLog(0, ("      entry %d: [%s] -> [%s]\n", ipaddr1_id, addrbuf1, addrbuf2));
 
     /* Change the registered uuuid addresses */
-    if (exp) {
+    if (exp && base != -1) {
        memset(&tuuid, 0, sizeof(afsUUID));
        afs_htonuuid(&tuuid);
        exp->ex_hostuuid = tuuid;