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328 lines
7.9 KiB
328 lines
7.9 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* AFS vlserver list management. |
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* |
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* Copyright (C) 2018 Red Hat, Inc. All Rights Reserved. |
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* Written by David Howells ([email protected]) |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/slab.h> |
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#include "internal.h" |
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struct afs_vlserver *afs_alloc_vlserver(const char *name, size_t name_len, |
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unsigned short port) |
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{ |
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struct afs_vlserver *vlserver; |
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vlserver = kzalloc(struct_size(vlserver, name, name_len + 1), |
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GFP_KERNEL); |
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if (vlserver) { |
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refcount_set(&vlserver->ref, 1); |
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rwlock_init(&vlserver->lock); |
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init_waitqueue_head(&vlserver->probe_wq); |
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spin_lock_init(&vlserver->probe_lock); |
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vlserver->rtt = UINT_MAX; |
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vlserver->name_len = name_len; |
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vlserver->port = port; |
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memcpy(vlserver->name, name, name_len); |
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} |
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return vlserver; |
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} |
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static void afs_vlserver_rcu(struct rcu_head *rcu) |
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{ |
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struct afs_vlserver *vlserver = container_of(rcu, struct afs_vlserver, rcu); |
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afs_put_addrlist(rcu_access_pointer(vlserver->addresses)); |
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kfree_rcu(vlserver, rcu); |
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} |
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void afs_put_vlserver(struct afs_net *net, struct afs_vlserver *vlserver) |
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{ |
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if (vlserver && |
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refcount_dec_and_test(&vlserver->ref)) |
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call_rcu(&vlserver->rcu, afs_vlserver_rcu); |
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} |
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struct afs_vlserver_list *afs_alloc_vlserver_list(unsigned int nr_servers) |
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{ |
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struct afs_vlserver_list *vllist; |
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vllist = kzalloc(struct_size(vllist, servers, nr_servers), GFP_KERNEL); |
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if (vllist) { |
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refcount_set(&vllist->ref, 1); |
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rwlock_init(&vllist->lock); |
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} |
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return vllist; |
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} |
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void afs_put_vlserverlist(struct afs_net *net, struct afs_vlserver_list *vllist) |
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{ |
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if (vllist) { |
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if (refcount_dec_and_test(&vllist->ref)) { |
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int i; |
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for (i = 0; i < vllist->nr_servers; i++) { |
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afs_put_vlserver(net, vllist->servers[i].server); |
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} |
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kfree_rcu(vllist, rcu); |
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} |
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} |
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} |
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static u16 afs_extract_le16(const u8 **_b) |
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{ |
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u16 val; |
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val = (u16)*(*_b)++ << 0; |
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val |= (u16)*(*_b)++ << 8; |
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return val; |
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} |
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/* |
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* Build a VL server address list from a DNS queried server list. |
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*/ |
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static struct afs_addr_list *afs_extract_vl_addrs(const u8 **_b, const u8 *end, |
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u8 nr_addrs, u16 port) |
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{ |
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struct afs_addr_list *alist; |
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const u8 *b = *_b; |
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int ret = -EINVAL; |
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alist = afs_alloc_addrlist(nr_addrs, VL_SERVICE, port); |
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if (!alist) |
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return ERR_PTR(-ENOMEM); |
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if (nr_addrs == 0) |
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return alist; |
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for (; nr_addrs > 0 && end - b >= nr_addrs; nr_addrs--) { |
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struct dns_server_list_v1_address hdr; |
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__be32 x[4]; |
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hdr.address_type = *b++; |
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switch (hdr.address_type) { |
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case DNS_ADDRESS_IS_IPV4: |
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if (end - b < 4) { |
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_leave(" = -EINVAL [short inet]"); |
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goto error; |
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} |
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memcpy(x, b, 4); |
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afs_merge_fs_addr4(alist, x[0], port); |
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b += 4; |
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break; |
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case DNS_ADDRESS_IS_IPV6: |
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if (end - b < 16) { |
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_leave(" = -EINVAL [short inet6]"); |
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goto error; |
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} |
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memcpy(x, b, 16); |
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afs_merge_fs_addr6(alist, x, port); |
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b += 16; |
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break; |
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default: |
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_leave(" = -EADDRNOTAVAIL [unknown af %u]", |
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hdr.address_type); |
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ret = -EADDRNOTAVAIL; |
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goto error; |
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} |
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} |
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/* Start with IPv6 if available. */ |
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if (alist->nr_ipv4 < alist->nr_addrs) |
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alist->preferred = alist->nr_ipv4; |
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*_b = b; |
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return alist; |
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error: |
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*_b = b; |
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afs_put_addrlist(alist); |
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return ERR_PTR(ret); |
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} |
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/* |
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* Build a VL server list from a DNS queried server list. |
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*/ |
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struct afs_vlserver_list *afs_extract_vlserver_list(struct afs_cell *cell, |
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const void *buffer, |
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size_t buffer_size) |
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{ |
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const struct dns_server_list_v1_header *hdr = buffer; |
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struct dns_server_list_v1_server bs; |
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struct afs_vlserver_list *vllist, *previous; |
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struct afs_addr_list *addrs; |
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struct afs_vlserver *server; |
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const u8 *b = buffer, *end = buffer + buffer_size; |
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int ret = -ENOMEM, nr_servers, i, j; |
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_enter(""); |
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/* Check that it's a server list, v1 */ |
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if (end - b < sizeof(*hdr) || |
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hdr->hdr.content != DNS_PAYLOAD_IS_SERVER_LIST || |
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hdr->hdr.version != 1) { |
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pr_notice("kAFS: Got DNS record [%u,%u] len %zu\n", |
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hdr->hdr.content, hdr->hdr.version, end - b); |
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ret = -EDESTADDRREQ; |
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goto dump; |
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} |
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nr_servers = hdr->nr_servers; |
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vllist = afs_alloc_vlserver_list(nr_servers); |
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if (!vllist) |
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return ERR_PTR(-ENOMEM); |
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vllist->source = (hdr->source < NR__dns_record_source) ? |
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hdr->source : NR__dns_record_source; |
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vllist->status = (hdr->status < NR__dns_lookup_status) ? |
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hdr->status : NR__dns_lookup_status; |
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read_lock(&cell->vl_servers_lock); |
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previous = afs_get_vlserverlist( |
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rcu_dereference_protected(cell->vl_servers, |
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lockdep_is_held(&cell->vl_servers_lock))); |
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read_unlock(&cell->vl_servers_lock); |
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b += sizeof(*hdr); |
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while (end - b >= sizeof(bs)) { |
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bs.name_len = afs_extract_le16(&b); |
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bs.priority = afs_extract_le16(&b); |
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bs.weight = afs_extract_le16(&b); |
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bs.port = afs_extract_le16(&b); |
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bs.source = *b++; |
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bs.status = *b++; |
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bs.protocol = *b++; |
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bs.nr_addrs = *b++; |
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_debug("extract %u %u %u %u %u %u %*.*s", |
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bs.name_len, bs.priority, bs.weight, |
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bs.port, bs.protocol, bs.nr_addrs, |
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bs.name_len, bs.name_len, b); |
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if (end - b < bs.name_len) |
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break; |
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ret = -EPROTONOSUPPORT; |
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if (bs.protocol == DNS_SERVER_PROTOCOL_UNSPECIFIED) { |
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bs.protocol = DNS_SERVER_PROTOCOL_UDP; |
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} else if (bs.protocol != DNS_SERVER_PROTOCOL_UDP) { |
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_leave(" = [proto %u]", bs.protocol); |
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goto error; |
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} |
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if (bs.port == 0) |
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bs.port = AFS_VL_PORT; |
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if (bs.source > NR__dns_record_source) |
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bs.source = NR__dns_record_source; |
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if (bs.status > NR__dns_lookup_status) |
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bs.status = NR__dns_lookup_status; |
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/* See if we can update an old server record */ |
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server = NULL; |
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for (i = 0; i < previous->nr_servers; i++) { |
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struct afs_vlserver *p = previous->servers[i].server; |
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if (p->name_len == bs.name_len && |
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p->port == bs.port && |
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strncasecmp(b, p->name, bs.name_len) == 0) { |
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server = afs_get_vlserver(p); |
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break; |
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} |
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} |
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if (!server) { |
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ret = -ENOMEM; |
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server = afs_alloc_vlserver(b, bs.name_len, bs.port); |
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if (!server) |
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goto error; |
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} |
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b += bs.name_len; |
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/* Extract the addresses - note that we can't skip this as we |
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* have to advance the payload pointer. |
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*/ |
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addrs = afs_extract_vl_addrs(&b, end, bs.nr_addrs, bs.port); |
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if (IS_ERR(addrs)) { |
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ret = PTR_ERR(addrs); |
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goto error_2; |
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} |
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if (vllist->nr_servers >= nr_servers) { |
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_debug("skip %u >= %u", vllist->nr_servers, nr_servers); |
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afs_put_addrlist(addrs); |
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afs_put_vlserver(cell->net, server); |
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continue; |
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} |
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addrs->source = bs.source; |
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addrs->status = bs.status; |
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if (addrs->nr_addrs == 0) { |
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afs_put_addrlist(addrs); |
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if (!rcu_access_pointer(server->addresses)) { |
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afs_put_vlserver(cell->net, server); |
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continue; |
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} |
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} else { |
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struct afs_addr_list *old = addrs; |
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write_lock(&server->lock); |
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old = rcu_replace_pointer(server->addresses, old, |
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lockdep_is_held(&server->lock)); |
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write_unlock(&server->lock); |
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afs_put_addrlist(old); |
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} |
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/* TODO: Might want to check for duplicates */ |
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/* Insertion-sort by priority and weight */ |
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for (j = 0; j < vllist->nr_servers; j++) { |
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if (bs.priority < vllist->servers[j].priority) |
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break; /* Lower preferable */ |
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if (bs.priority == vllist->servers[j].priority && |
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bs.weight > vllist->servers[j].weight) |
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break; /* Higher preferable */ |
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} |
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if (j < vllist->nr_servers) { |
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memmove(vllist->servers + j + 1, |
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vllist->servers + j, |
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(vllist->nr_servers - j) * sizeof(struct afs_vlserver_entry)); |
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} |
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clear_bit(AFS_VLSERVER_FL_PROBED, &server->flags); |
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vllist->servers[j].priority = bs.priority; |
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vllist->servers[j].weight = bs.weight; |
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vllist->servers[j].server = server; |
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vllist->nr_servers++; |
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} |
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if (b != end) { |
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_debug("parse error %zd", b - end); |
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goto error; |
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} |
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afs_put_vlserverlist(cell->net, previous); |
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_leave(" = ok [%u]", vllist->nr_servers); |
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return vllist; |
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error_2: |
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afs_put_vlserver(cell->net, server); |
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error: |
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afs_put_vlserverlist(cell->net, vllist); |
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afs_put_vlserverlist(cell->net, previous); |
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dump: |
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if (ret != -ENOMEM) { |
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printk(KERN_DEBUG "DNS: at %zu\n", (const void *)b - buffer); |
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print_hex_dump_bytes("DNS: ", DUMP_PREFIX_NONE, buffer, buffer_size); |
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} |
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return ERR_PTR(ret); |
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}
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