afs: Make use of the YFS service upgrade to fully support IPv6

YFS VL servers offer an upgraded Volume Location service that can return
IPv6 addresses to fileservers and volume servers in addition to IPv4
addresses using the YFSVL.GetEndpoints operation which we should use if
it's available.

To this end:

 (1) Make rxrpc_kernel_recv_data() return the call's current service ID so
     that the caller can detect service upgrade and see what the service
     was upgraded to.

 (2) When we see a VL server address we haven't seen before, send a
     VL.GetCapabilities operation to it with the service upgrade bit set.

     If we get an upgrade to the YFS VL service, change the service ID in
     the address list for that address to use the upgraded service and set
     a flag to note that this appears to be a YFS-compatible server.

 (3) If, when a server's addresses are being looked up, we note that we
     previously detected a YFS-compatible server, then send the
     YFSVL.GetEndpoints operation rather than VL.GetAddrsU.

 (4) Build a fileserver address list from the reply of YFSVL.GetEndpoints,
     including both IPv4 and IPv6 addresses.  Volume server addresses are
     discarded.

 (5) The address list is sorted by address and port now, instead of just
     address.  This allows multiple servers on the same host sitting on
     different ports.

Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 48 insertions, 6 deletions

diff --git a/fs/afs/addr_list.c b/fs/afs/addr_list.c
index b91e59a77f0e..a537368ba0db 100644
--- a/fs/afs/addr_list.c
+++ b/fs/afs/addr_list.c
@@ -17,9 +17,10 @@
 #include "internal.h"
 #include "afs_fs.h"
 
-#define AFS_MAX_ADDRESSES						\
-	((unsigned int)((PAGE_SIZE - sizeof(struct afs_addr_list)) /	\
-			sizeof(struct sockaddr_rxrpc)))
+//#define AFS_MAX_ADDRESSES
+//	((unsigned int)((PAGE_SIZE - sizeof(struct afs_addr_list)) /
+//			sizeof(struct sockaddr_rxrpc)))
+#define AFS_MAX_ADDRESSES ((unsigned int)(sizeof(unsigned long) * 8))
 
 /*
  * Release an address list.
@@ -230,15 +231,20 @@ struct afs_addr_list *afs_dns_query(struct afs_cell *cell, time64_t *_expiry)
 /*
  * Merge an IPv4 entry into a fileserver address list.
  */
-void afs_merge_fs_addr4(struct afs_addr_list *alist, __be32 xdr)
+void afs_merge_fs_addr4(struct afs_addr_list *alist, __be32 xdr, u16 port)
 {
 	struct sockaddr_in6 *a;
+	__be16 xport = htons(port);
 	int i;
 
 	for (i = 0; i < alist->nr_ipv4; i++) {
 		a = &alist->addrs[i].transport.sin6;
-		if (xdr == a->sin6_addr.s6_addr32[3])
+		if (xdr == a->sin6_addr.s6_addr32[3] &&
+		    xport == a->sin6_port)
 			return;
+		if (xdr == a->sin6_addr.s6_addr32[3] &&
+		    xport < a->sin6_port)
+			break;
 		if (xdr < a->sin6_addr.s6_addr32[3])
 			break;
 	}
@@ -249,7 +255,7 @@ void afs_merge_fs_addr4(struct afs_addr_list *alist, __be32 xdr)
 			sizeof(alist->addrs[0]) * (alist->nr_addrs - i));
 
 	a = &alist->addrs[i].transport.sin6;
-	a->sin6_port		  = htons(AFS_FS_PORT);
+	a->sin6_port		  = xport;
 	a->sin6_addr.s6_addr32[0] = 0;
 	a->sin6_addr.s6_addr32[1] = 0;
 	a->sin6_addr.s6_addr32[2] = htonl(0xffff);
@@ -259,6 +265,42 @@ void afs_merge_fs_addr4(struct afs_addr_list *alist, __be32 xdr)
 }
 
 /*
+ * Merge an IPv6 entry into a fileserver address list.
+ */
+void afs_merge_fs_addr6(struct afs_addr_list *alist, __be32 *xdr, u16 port)
+{
+	struct sockaddr_in6 *a;
+	__be16 xport = htons(port);
+	int i, diff;
+
+	for (i = alist->nr_ipv4; i < alist->nr_addrs; i++) {
+		a = &alist->addrs[i].transport.sin6;
+		diff = memcmp(xdr, &a->sin6_addr, 16);
+		if (diff == 0 &&
+		    xport == a->sin6_port)
+			return;
+		if (diff == 0 &&
+		    xport < a->sin6_port)
+			break;
+		if (diff < 0)
+			break;
+	}
+
+	if (i < alist->nr_addrs)
+		memmove(alist->addrs + i + 1,
+			alist->addrs + i,
+			sizeof(alist->addrs[0]) * (alist->nr_addrs - i));
+
+	a = &alist->addrs[i].transport.sin6;
+	a->sin6_port		  = xport;
+	a->sin6_addr.s6_addr32[0] = xdr[0];
+	a->sin6_addr.s6_addr32[1] = xdr[1];
+	a->sin6_addr.s6_addr32[2] = xdr[2];
+	a->sin6_addr.s6_addr32[3] = xdr[3];
+	alist->nr_addrs++;
+}
+
+/*
  * Get an address to try.
  */
 bool afs_iterate_addresses(struct afs_addr_cursor *ac)