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-rw-r--r--fs/afs/vl_list.c336
1 files changed, 336 insertions, 0 deletions
diff --git a/fs/afs/vl_list.c b/fs/afs/vl_list.c
new file mode 100644
index 000000000000..c1e316ba105a
--- /dev/null
+++ b/fs/afs/vl_list.c
@@ -0,0 +1,336 @@
+/* AFS vlserver list management.
+ *
+ * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include "internal.h"
+
+struct afs_vlserver *afs_alloc_vlserver(const char *name, size_t name_len,
+ unsigned short port)
+{
+ struct afs_vlserver *vlserver;
+
+ vlserver = kzalloc(struct_size(vlserver, name, name_len + 1),
+ GFP_KERNEL);
+ if (vlserver) {
+ atomic_set(&vlserver->usage, 1);
+ rwlock_init(&vlserver->lock);
+ vlserver->name_len = name_len;
+ vlserver->port = port;
+ memcpy(vlserver->name, name, name_len);
+ }
+ return vlserver;
+}
+
+static void afs_vlserver_rcu(struct rcu_head *rcu)
+{
+ struct afs_vlserver *vlserver = container_of(rcu, struct afs_vlserver, rcu);
+
+ afs_put_addrlist(rcu_access_pointer(vlserver->addresses));
+ kfree_rcu(vlserver, rcu);
+}
+
+void afs_put_vlserver(struct afs_net *net, struct afs_vlserver *vlserver)
+{
+ if (vlserver) {
+ unsigned int u = atomic_dec_return(&vlserver->usage);
+ //_debug("VL PUT %p{%u}", vlserver, u);
+
+ if (u == 0)
+ call_rcu(&vlserver->rcu, afs_vlserver_rcu);
+ }
+}
+
+struct afs_vlserver_list *afs_alloc_vlserver_list(unsigned int nr_servers)
+{
+ struct afs_vlserver_list *vllist;
+
+ vllist = kzalloc(struct_size(vllist, servers, nr_servers), GFP_KERNEL);
+ if (vllist) {
+ atomic_set(&vllist->usage, 1);
+ rwlock_init(&vllist->lock);
+ }
+
+ return vllist;
+}
+
+void afs_put_vlserverlist(struct afs_net *net, struct afs_vlserver_list *vllist)
+{
+ if (vllist) {
+ unsigned int u = atomic_dec_return(&vllist->usage);
+
+ //_debug("VLLS PUT %p{%u}", vllist, u);
+ if (u == 0) {
+ int i;
+
+ for (i = 0; i < vllist->nr_servers; i++) {
+ afs_put_vlserver(net, vllist->servers[i].server);
+ }
+ kfree_rcu(vllist, rcu);
+ }
+ }
+}
+
+static u16 afs_extract_le16(const u8 **_b)
+{
+ u16 val;
+
+ val = (u16)*(*_b)++ << 0;
+ val |= (u16)*(*_b)++ << 8;
+ return val;
+}
+
+/*
+ * Build a VL server address list from a DNS queried server list.
+ */
+static struct afs_addr_list *afs_extract_vl_addrs(const u8 **_b, const u8 *end,
+ u8 nr_addrs, u16 port)
+{
+ struct afs_addr_list *alist;
+ const u8 *b = *_b;
+ int ret = -EINVAL;
+
+ alist = afs_alloc_addrlist(nr_addrs, VL_SERVICE, port);
+ if (!alist)
+ return ERR_PTR(-ENOMEM);
+ if (nr_addrs == 0)
+ return alist;
+
+ for (; nr_addrs > 0 && end - b >= nr_addrs; nr_addrs--) {
+ struct dns_server_list_v1_address hdr;
+ __be32 x[4];
+
+ hdr.address_type = *b++;
+
+ switch (hdr.address_type) {
+ case DNS_ADDRESS_IS_IPV4:
+ if (end - b < 4) {
+ _leave(" = -EINVAL [short inet]");
+ goto error;
+ }
+ memcpy(x, b, 4);
+ afs_merge_fs_addr4(alist, x[0], port);
+ b += 4;
+ break;
+
+ case DNS_ADDRESS_IS_IPV6:
+ if (end - b < 16) {
+ _leave(" = -EINVAL [short inet6]");
+ goto error;
+ }
+ memcpy(x, b, 16);
+ afs_merge_fs_addr6(alist, x, port);
+ b += 16;
+ break;
+
+ default:
+ _leave(" = -EADDRNOTAVAIL [unknown af %u]",
+ hdr.address_type);
+ ret = -EADDRNOTAVAIL;
+ goto error;
+ }
+ }
+
+ /* Start with IPv6 if available. */
+ if (alist->nr_ipv4 < alist->nr_addrs)
+ alist->index = alist->nr_ipv4;
+
+ *_b = b;
+ return alist;
+
+error:
+ *_b = b;
+ afs_put_addrlist(alist);
+ return ERR_PTR(ret);
+}
+
+/*
+ * Build a VL server list from a DNS queried server list.
+ */
+struct afs_vlserver_list *afs_extract_vlserver_list(struct afs_cell *cell,
+ const void *buffer,
+ size_t buffer_size)
+{
+ const struct dns_server_list_v1_header *hdr = buffer;
+ struct dns_server_list_v1_server bs;
+ struct afs_vlserver_list *vllist, *previous;
+ struct afs_addr_list *addrs;
+ struct afs_vlserver *server;
+ const u8 *b = buffer, *end = buffer + buffer_size;
+ int ret = -ENOMEM, nr_servers, i, j;
+
+ _enter("");
+
+ /* Check that it's a server list, v1 */
+ if (end - b < sizeof(*hdr) ||
+ hdr->hdr.content != DNS_PAYLOAD_IS_SERVER_LIST ||
+ hdr->hdr.version != 1) {
+ pr_notice("kAFS: Got DNS record [%u,%u] len %zu\n",
+ hdr->hdr.content, hdr->hdr.version, end - b);
+ ret = -EDESTADDRREQ;
+ goto dump;
+ }
+
+ nr_servers = hdr->nr_servers;
+
+ vllist = afs_alloc_vlserver_list(nr_servers);
+ if (!vllist)
+ return ERR_PTR(-ENOMEM);
+
+ vllist->source = (hdr->source < NR__dns_record_source) ?
+ hdr->source : NR__dns_record_source;
+ vllist->status = (hdr->status < NR__dns_lookup_status) ?
+ hdr->status : NR__dns_lookup_status;
+
+ read_lock(&cell->vl_servers_lock);
+ previous = afs_get_vlserverlist(
+ rcu_dereference_protected(cell->vl_servers,
+ lockdep_is_held(&cell->vl_servers_lock)));
+ read_unlock(&cell->vl_servers_lock);
+
+ b += sizeof(*hdr);
+ while (end - b >= sizeof(bs)) {
+ bs.name_len = afs_extract_le16(&b);
+ bs.priority = afs_extract_le16(&b);
+ bs.weight = afs_extract_le16(&b);
+ bs.port = afs_extract_le16(&b);
+ bs.source = *b++;
+ bs.status = *b++;
+ bs.protocol = *b++;
+ bs.nr_addrs = *b++;
+
+ _debug("extract %u %u %u %u %u %u %*.*s",
+ bs.name_len, bs.priority, bs.weight,
+ bs.port, bs.protocol, bs.nr_addrs,
+ bs.name_len, bs.name_len, b);
+
+ if (end - b < bs.name_len)
+ break;
+
+ ret = -EPROTONOSUPPORT;
+ if (bs.protocol == DNS_SERVER_PROTOCOL_UNSPECIFIED) {
+ bs.protocol = DNS_SERVER_PROTOCOL_UDP;
+ } else if (bs.protocol != DNS_SERVER_PROTOCOL_UDP) {
+ _leave(" = [proto %u]", bs.protocol);
+ goto error;
+ }
+
+ if (bs.port == 0)
+ bs.port = AFS_VL_PORT;
+ if (bs.source > NR__dns_record_source)
+ bs.source = NR__dns_record_source;
+ if (bs.status > NR__dns_lookup_status)
+ bs.status = NR__dns_lookup_status;
+
+ server = NULL;
+ if (previous) {
+ /* See if we can update an old server record */
+ for (i = 0; i < previous->nr_servers; i++) {
+ struct afs_vlserver *p = previous->servers[i].server;
+
+ if (p->name_len == bs.name_len &&
+ p->port == bs.port &&
+ strncasecmp(b, p->name, bs.name_len) == 0) {
+ server = afs_get_vlserver(p);
+ break;
+ }
+ }
+ }
+
+ if (!server) {
+ ret = -ENOMEM;
+ server = afs_alloc_vlserver(b, bs.name_len, bs.port);
+ if (!server)
+ goto error;
+ }
+
+ b += bs.name_len;
+
+ /* Extract the addresses - note that we can't skip this as we
+ * have to advance the payload pointer.
+ */
+ addrs = afs_extract_vl_addrs(&b, end, bs.nr_addrs, bs.port);
+ if (IS_ERR(addrs)) {
+ ret = PTR_ERR(addrs);
+ goto error_2;
+ }
+
+ if (vllist->nr_servers >= nr_servers) {
+ _debug("skip %u >= %u", vllist->nr_servers, nr_servers);
+ afs_put_addrlist(addrs);
+ afs_put_vlserver(cell->net, server);
+ continue;
+ }
+
+ addrs->source = bs.source;
+ addrs->status = bs.status;
+
+ if (addrs->nr_addrs == 0) {
+ afs_put_addrlist(addrs);
+ if (!rcu_access_pointer(server->addresses)) {
+ afs_put_vlserver(cell->net, server);
+ continue;
+ }
+ } else {
+ struct afs_addr_list *old = addrs;
+
+ write_lock(&server->lock);
+ rcu_swap_protected(server->addresses, old,
+ lockdep_is_held(&server->lock));
+ write_unlock(&server->lock);
+ afs_put_addrlist(old);
+ }
+
+
+ /* TODO: Might want to check for duplicates */
+
+ /* Insertion-sort by priority and weight */
+ for (j = 0; j < vllist->nr_servers; j++) {
+ if (bs.priority < vllist->servers[j].priority)
+ break; /* Lower preferable */
+ if (bs.priority == vllist->servers[j].priority &&
+ bs.weight > vllist->servers[j].weight)
+ break; /* Higher preferable */
+ }
+
+ if (j < vllist->nr_servers) {
+ memmove(vllist->servers + j + 1,
+ vllist->servers + j,
+ (vllist->nr_servers - j) * sizeof(struct afs_vlserver_entry));
+ }
+
+ vllist->servers[j].priority = bs.priority;
+ vllist->servers[j].weight = bs.weight;
+ vllist->servers[j].server = server;
+ vllist->nr_servers++;
+ }
+
+ if (b != end) {
+ _debug("parse error %zd", b - end);
+ goto error;
+ }
+
+ afs_put_vlserverlist(cell->net, previous);
+ _leave(" = ok [%u]", vllist->nr_servers);
+ return vllist;
+
+error_2:
+ afs_put_vlserver(cell->net, server);
+error:
+ afs_put_vlserverlist(cell->net, vllist);
+ afs_put_vlserverlist(cell->net, previous);
+dump:
+ if (ret != -ENOMEM) {
+ printk(KERN_DEBUG "DNS: at %zu\n", (const void *)b - buffer);
+ print_hex_dump_bytes("DNS: ", DUMP_PREFIX_NONE, buffer, buffer_size);
+ }
+ return ERR_PTR(ret);
+}