| /* 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); |
| init_waitqueue_head(&vlserver->probe_wq); |
| spin_lock_init(&vlserver->probe_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->preferred = 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; |
| |
| /* See if we can update an old server record */ |
| server = NULL; |
| 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)); |
| } |
| |
| clear_bit(AFS_VLSERVER_FL_PROBED, &server->flags); |
| |
| 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); |
| } |