12874c5fdSThomas Gleixner // SPDX-License-Identifier: GPL-2.0-or-later
20a5143f2SDavid Howells /* AFS vlserver list management.
30a5143f2SDavid Howells *
40a5143f2SDavid Howells * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
50a5143f2SDavid Howells * Written by David Howells (dhowells@redhat.com)
60a5143f2SDavid Howells */
70a5143f2SDavid Howells
80a5143f2SDavid Howells #include <linux/kernel.h>
90a5143f2SDavid Howells #include <linux/slab.h>
100a5143f2SDavid Howells #include "internal.h"
110a5143f2SDavid Howells
afs_alloc_vlserver(const char * name,size_t name_len,unsigned short port)120a5143f2SDavid Howells struct afs_vlserver *afs_alloc_vlserver(const char *name, size_t name_len,
130a5143f2SDavid Howells unsigned short port)
140a5143f2SDavid Howells {
150a5143f2SDavid Howells struct afs_vlserver *vlserver;
160a5143f2SDavid Howells
170a5143f2SDavid Howells vlserver = kzalloc(struct_size(vlserver, name, name_len + 1),
180a5143f2SDavid Howells GFP_KERNEL);
190a5143f2SDavid Howells if (vlserver) {
20*c56f9ec8SDavid Howells refcount_set(&vlserver->ref, 1);
210a5143f2SDavid Howells rwlock_init(&vlserver->lock);
223bf0fb6fSDavid Howells init_waitqueue_head(&vlserver->probe_wq);
233bf0fb6fSDavid Howells spin_lock_init(&vlserver->probe_lock);
24b95b3094SDavid Howells vlserver->rtt = UINT_MAX;
250a5143f2SDavid Howells vlserver->name_len = name_len;
260a5143f2SDavid Howells vlserver->port = port;
270a5143f2SDavid Howells memcpy(vlserver->name, name, name_len);
280a5143f2SDavid Howells }
290a5143f2SDavid Howells return vlserver;
300a5143f2SDavid Howells }
310a5143f2SDavid Howells
afs_vlserver_rcu(struct rcu_head * rcu)320a5143f2SDavid Howells static void afs_vlserver_rcu(struct rcu_head *rcu)
330a5143f2SDavid Howells {
340a5143f2SDavid Howells struct afs_vlserver *vlserver = container_of(rcu, struct afs_vlserver, rcu);
350a5143f2SDavid Howells
360a5143f2SDavid Howells afs_put_addrlist(rcu_access_pointer(vlserver->addresses));
370a5143f2SDavid Howells kfree_rcu(vlserver, rcu);
380a5143f2SDavid Howells }
390a5143f2SDavid Howells
afs_put_vlserver(struct afs_net * net,struct afs_vlserver * vlserver)400a5143f2SDavid Howells void afs_put_vlserver(struct afs_net *net, struct afs_vlserver *vlserver)
410a5143f2SDavid Howells {
42*c56f9ec8SDavid Howells if (vlserver &&
43*c56f9ec8SDavid Howells refcount_dec_and_test(&vlserver->ref))
440a5143f2SDavid Howells call_rcu(&vlserver->rcu, afs_vlserver_rcu);
450a5143f2SDavid Howells }
460a5143f2SDavid Howells
afs_alloc_vlserver_list(unsigned int nr_servers)470a5143f2SDavid Howells struct afs_vlserver_list *afs_alloc_vlserver_list(unsigned int nr_servers)
480a5143f2SDavid Howells {
490a5143f2SDavid Howells struct afs_vlserver_list *vllist;
500a5143f2SDavid Howells
510a5143f2SDavid Howells vllist = kzalloc(struct_size(vllist, servers, nr_servers), GFP_KERNEL);
520a5143f2SDavid Howells if (vllist) {
53*c56f9ec8SDavid Howells refcount_set(&vllist->ref, 1);
540a5143f2SDavid Howells rwlock_init(&vllist->lock);
550a5143f2SDavid Howells }
560a5143f2SDavid Howells
570a5143f2SDavid Howells return vllist;
580a5143f2SDavid Howells }
590a5143f2SDavid Howells
afs_put_vlserverlist(struct afs_net * net,struct afs_vlserver_list * vllist)600a5143f2SDavid Howells void afs_put_vlserverlist(struct afs_net *net, struct afs_vlserver_list *vllist)
610a5143f2SDavid Howells {
620a5143f2SDavid Howells if (vllist) {
63*c56f9ec8SDavid Howells if (refcount_dec_and_test(&vllist->ref)) {
640a5143f2SDavid Howells int i;
650a5143f2SDavid Howells
660a5143f2SDavid Howells for (i = 0; i < vllist->nr_servers; i++) {
670a5143f2SDavid Howells afs_put_vlserver(net, vllist->servers[i].server);
680a5143f2SDavid Howells }
690a5143f2SDavid Howells kfree_rcu(vllist, rcu);
700a5143f2SDavid Howells }
710a5143f2SDavid Howells }
720a5143f2SDavid Howells }
730a5143f2SDavid Howells
afs_extract_le16(const u8 ** _b)740a5143f2SDavid Howells static u16 afs_extract_le16(const u8 **_b)
750a5143f2SDavid Howells {
760a5143f2SDavid Howells u16 val;
770a5143f2SDavid Howells
780a5143f2SDavid Howells val = (u16)*(*_b)++ << 0;
790a5143f2SDavid Howells val |= (u16)*(*_b)++ << 8;
800a5143f2SDavid Howells return val;
810a5143f2SDavid Howells }
820a5143f2SDavid Howells
830a5143f2SDavid Howells /*
840a5143f2SDavid Howells * Build a VL server address list from a DNS queried server list.
850a5143f2SDavid Howells */
afs_extract_vl_addrs(const u8 ** _b,const u8 * end,u8 nr_addrs,u16 port)860a5143f2SDavid Howells static struct afs_addr_list *afs_extract_vl_addrs(const u8 **_b, const u8 *end,
870a5143f2SDavid Howells u8 nr_addrs, u16 port)
880a5143f2SDavid Howells {
890a5143f2SDavid Howells struct afs_addr_list *alist;
900a5143f2SDavid Howells const u8 *b = *_b;
910a5143f2SDavid Howells int ret = -EINVAL;
920a5143f2SDavid Howells
930a5143f2SDavid Howells alist = afs_alloc_addrlist(nr_addrs, VL_SERVICE, port);
940a5143f2SDavid Howells if (!alist)
950a5143f2SDavid Howells return ERR_PTR(-ENOMEM);
960a5143f2SDavid Howells if (nr_addrs == 0)
970a5143f2SDavid Howells return alist;
980a5143f2SDavid Howells
990a5143f2SDavid Howells for (; nr_addrs > 0 && end - b >= nr_addrs; nr_addrs--) {
1000a5143f2SDavid Howells struct dns_server_list_v1_address hdr;
1010a5143f2SDavid Howells __be32 x[4];
1020a5143f2SDavid Howells
1030a5143f2SDavid Howells hdr.address_type = *b++;
1040a5143f2SDavid Howells
1050a5143f2SDavid Howells switch (hdr.address_type) {
1060a5143f2SDavid Howells case DNS_ADDRESS_IS_IPV4:
1070a5143f2SDavid Howells if (end - b < 4) {
1080a5143f2SDavid Howells _leave(" = -EINVAL [short inet]");
1090a5143f2SDavid Howells goto error;
1100a5143f2SDavid Howells }
1110a5143f2SDavid Howells memcpy(x, b, 4);
1120a5143f2SDavid Howells afs_merge_fs_addr4(alist, x[0], port);
1130a5143f2SDavid Howells b += 4;
1140a5143f2SDavid Howells break;
1150a5143f2SDavid Howells
1160a5143f2SDavid Howells case DNS_ADDRESS_IS_IPV6:
1170a5143f2SDavid Howells if (end - b < 16) {
1180a5143f2SDavid Howells _leave(" = -EINVAL [short inet6]");
1190a5143f2SDavid Howells goto error;
1200a5143f2SDavid Howells }
1210a5143f2SDavid Howells memcpy(x, b, 16);
1220a5143f2SDavid Howells afs_merge_fs_addr6(alist, x, port);
1230a5143f2SDavid Howells b += 16;
1240a5143f2SDavid Howells break;
1250a5143f2SDavid Howells
1260a5143f2SDavid Howells default:
1270a5143f2SDavid Howells _leave(" = -EADDRNOTAVAIL [unknown af %u]",
1280a5143f2SDavid Howells hdr.address_type);
1290a5143f2SDavid Howells ret = -EADDRNOTAVAIL;
1300a5143f2SDavid Howells goto error;
1310a5143f2SDavid Howells }
1320a5143f2SDavid Howells }
1330a5143f2SDavid Howells
1340a5143f2SDavid Howells /* Start with IPv6 if available. */
1350a5143f2SDavid Howells if (alist->nr_ipv4 < alist->nr_addrs)
1363bf0fb6fSDavid Howells alist->preferred = alist->nr_ipv4;
1370a5143f2SDavid Howells
1380a5143f2SDavid Howells *_b = b;
1390a5143f2SDavid Howells return alist;
1400a5143f2SDavid Howells
1410a5143f2SDavid Howells error:
1420a5143f2SDavid Howells *_b = b;
1430a5143f2SDavid Howells afs_put_addrlist(alist);
1440a5143f2SDavid Howells return ERR_PTR(ret);
1450a5143f2SDavid Howells }
1460a5143f2SDavid Howells
1470a5143f2SDavid Howells /*
1480a5143f2SDavid Howells * Build a VL server list from a DNS queried server list.
1490a5143f2SDavid Howells */
afs_extract_vlserver_list(struct afs_cell * cell,const void * buffer,size_t buffer_size)1500a5143f2SDavid Howells struct afs_vlserver_list *afs_extract_vlserver_list(struct afs_cell *cell,
1510a5143f2SDavid Howells const void *buffer,
1520a5143f2SDavid Howells size_t buffer_size)
1530a5143f2SDavid Howells {
1540a5143f2SDavid Howells const struct dns_server_list_v1_header *hdr = buffer;
1550a5143f2SDavid Howells struct dns_server_list_v1_server bs;
1560a5143f2SDavid Howells struct afs_vlserver_list *vllist, *previous;
1570a5143f2SDavid Howells struct afs_addr_list *addrs;
1580a5143f2SDavid Howells struct afs_vlserver *server;
1590a5143f2SDavid Howells const u8 *b = buffer, *end = buffer + buffer_size;
1600a5143f2SDavid Howells int ret = -ENOMEM, nr_servers, i, j;
1610a5143f2SDavid Howells
1620a5143f2SDavid Howells _enter("");
1630a5143f2SDavid Howells
1640a5143f2SDavid Howells /* Check that it's a server list, v1 */
1650a5143f2SDavid Howells if (end - b < sizeof(*hdr) ||
1660a5143f2SDavid Howells hdr->hdr.content != DNS_PAYLOAD_IS_SERVER_LIST ||
1670a5143f2SDavid Howells hdr->hdr.version != 1) {
1680a5143f2SDavid Howells pr_notice("kAFS: Got DNS record [%u,%u] len %zu\n",
1690a5143f2SDavid Howells hdr->hdr.content, hdr->hdr.version, end - b);
1700a5143f2SDavid Howells ret = -EDESTADDRREQ;
1710a5143f2SDavid Howells goto dump;
1720a5143f2SDavid Howells }
1730a5143f2SDavid Howells
1740a5143f2SDavid Howells nr_servers = hdr->nr_servers;
1750a5143f2SDavid Howells
1760a5143f2SDavid Howells vllist = afs_alloc_vlserver_list(nr_servers);
1770a5143f2SDavid Howells if (!vllist)
1780a5143f2SDavid Howells return ERR_PTR(-ENOMEM);
1790a5143f2SDavid Howells
1800a5143f2SDavid Howells vllist->source = (hdr->source < NR__dns_record_source) ?
1810a5143f2SDavid Howells hdr->source : NR__dns_record_source;
1820a5143f2SDavid Howells vllist->status = (hdr->status < NR__dns_lookup_status) ?
1830a5143f2SDavid Howells hdr->status : NR__dns_lookup_status;
1840a5143f2SDavid Howells
1850a5143f2SDavid Howells read_lock(&cell->vl_servers_lock);
1860a5143f2SDavid Howells previous = afs_get_vlserverlist(
1870a5143f2SDavid Howells rcu_dereference_protected(cell->vl_servers,
1880a5143f2SDavid Howells lockdep_is_held(&cell->vl_servers_lock)));
1890a5143f2SDavid Howells read_unlock(&cell->vl_servers_lock);
1900a5143f2SDavid Howells
1910a5143f2SDavid Howells b += sizeof(*hdr);
1920a5143f2SDavid Howells while (end - b >= sizeof(bs)) {
1930a5143f2SDavid Howells bs.name_len = afs_extract_le16(&b);
1940a5143f2SDavid Howells bs.priority = afs_extract_le16(&b);
1950a5143f2SDavid Howells bs.weight = afs_extract_le16(&b);
1960a5143f2SDavid Howells bs.port = afs_extract_le16(&b);
1970a5143f2SDavid Howells bs.source = *b++;
1980a5143f2SDavid Howells bs.status = *b++;
1990a5143f2SDavid Howells bs.protocol = *b++;
2000a5143f2SDavid Howells bs.nr_addrs = *b++;
2010a5143f2SDavid Howells
2020a5143f2SDavid Howells _debug("extract %u %u %u %u %u %u %*.*s",
2030a5143f2SDavid Howells bs.name_len, bs.priority, bs.weight,
2040a5143f2SDavid Howells bs.port, bs.protocol, bs.nr_addrs,
2050a5143f2SDavid Howells bs.name_len, bs.name_len, b);
2060a5143f2SDavid Howells
2070a5143f2SDavid Howells if (end - b < bs.name_len)
2080a5143f2SDavid Howells break;
2090a5143f2SDavid Howells
2100a5143f2SDavid Howells ret = -EPROTONOSUPPORT;
2110a5143f2SDavid Howells if (bs.protocol == DNS_SERVER_PROTOCOL_UNSPECIFIED) {
2120a5143f2SDavid Howells bs.protocol = DNS_SERVER_PROTOCOL_UDP;
2130a5143f2SDavid Howells } else if (bs.protocol != DNS_SERVER_PROTOCOL_UDP) {
2140a5143f2SDavid Howells _leave(" = [proto %u]", bs.protocol);
2150a5143f2SDavid Howells goto error;
2160a5143f2SDavid Howells }
2170a5143f2SDavid Howells
2180a5143f2SDavid Howells if (bs.port == 0)
2190a5143f2SDavid Howells bs.port = AFS_VL_PORT;
2200a5143f2SDavid Howells if (bs.source > NR__dns_record_source)
2210a5143f2SDavid Howells bs.source = NR__dns_record_source;
2220a5143f2SDavid Howells if (bs.status > NR__dns_lookup_status)
2230a5143f2SDavid Howells bs.status = NR__dns_lookup_status;
2240a5143f2SDavid Howells
2250a5143f2SDavid Howells /* See if we can update an old server record */
226ca1cbbdcSDavid Howells server = NULL;
2270a5143f2SDavid Howells for (i = 0; i < previous->nr_servers; i++) {
2280a5143f2SDavid Howells struct afs_vlserver *p = previous->servers[i].server;
2290a5143f2SDavid Howells
2300a5143f2SDavid Howells if (p->name_len == bs.name_len &&
2310a5143f2SDavid Howells p->port == bs.port &&
2320a5143f2SDavid Howells strncasecmp(b, p->name, bs.name_len) == 0) {
2330a5143f2SDavid Howells server = afs_get_vlserver(p);
2340a5143f2SDavid Howells break;
2350a5143f2SDavid Howells }
2360a5143f2SDavid Howells }
2370a5143f2SDavid Howells
2380a5143f2SDavid Howells if (!server) {
2390a5143f2SDavid Howells ret = -ENOMEM;
2400a5143f2SDavid Howells server = afs_alloc_vlserver(b, bs.name_len, bs.port);
2410a5143f2SDavid Howells if (!server)
2420a5143f2SDavid Howells goto error;
2430a5143f2SDavid Howells }
2440a5143f2SDavid Howells
2450a5143f2SDavid Howells b += bs.name_len;
2460a5143f2SDavid Howells
2470a5143f2SDavid Howells /* Extract the addresses - note that we can't skip this as we
2480a5143f2SDavid Howells * have to advance the payload pointer.
2490a5143f2SDavid Howells */
2500a5143f2SDavid Howells addrs = afs_extract_vl_addrs(&b, end, bs.nr_addrs, bs.port);
2510a5143f2SDavid Howells if (IS_ERR(addrs)) {
2520a5143f2SDavid Howells ret = PTR_ERR(addrs);
2530a5143f2SDavid Howells goto error_2;
2540a5143f2SDavid Howells }
2550a5143f2SDavid Howells
2560a5143f2SDavid Howells if (vllist->nr_servers >= nr_servers) {
2570a5143f2SDavid Howells _debug("skip %u >= %u", vllist->nr_servers, nr_servers);
2580a5143f2SDavid Howells afs_put_addrlist(addrs);
2590a5143f2SDavid Howells afs_put_vlserver(cell->net, server);
2600a5143f2SDavid Howells continue;
2610a5143f2SDavid Howells }
2620a5143f2SDavid Howells
2630a5143f2SDavid Howells addrs->source = bs.source;
2640a5143f2SDavid Howells addrs->status = bs.status;
2650a5143f2SDavid Howells
2660a5143f2SDavid Howells if (addrs->nr_addrs == 0) {
2670a5143f2SDavid Howells afs_put_addrlist(addrs);
2680a5143f2SDavid Howells if (!rcu_access_pointer(server->addresses)) {
2690a5143f2SDavid Howells afs_put_vlserver(cell->net, server);
2700a5143f2SDavid Howells continue;
2710a5143f2SDavid Howells }
2720a5143f2SDavid Howells } else {
2730a5143f2SDavid Howells struct afs_addr_list *old = addrs;
2740a5143f2SDavid Howells
2750a5143f2SDavid Howells write_lock(&server->lock);
27662860da7SPaul E. McKenney old = rcu_replace_pointer(server->addresses, old,
2770a5143f2SDavid Howells lockdep_is_held(&server->lock));
2780a5143f2SDavid Howells write_unlock(&server->lock);
2790a5143f2SDavid Howells afs_put_addrlist(old);
2800a5143f2SDavid Howells }
2810a5143f2SDavid Howells
2820a5143f2SDavid Howells
2830a5143f2SDavid Howells /* TODO: Might want to check for duplicates */
2840a5143f2SDavid Howells
2850a5143f2SDavid Howells /* Insertion-sort by priority and weight */
2860a5143f2SDavid Howells for (j = 0; j < vllist->nr_servers; j++) {
2870a5143f2SDavid Howells if (bs.priority < vllist->servers[j].priority)
2880a5143f2SDavid Howells break; /* Lower preferable */
2890a5143f2SDavid Howells if (bs.priority == vllist->servers[j].priority &&
2900a5143f2SDavid Howells bs.weight > vllist->servers[j].weight)
2910a5143f2SDavid Howells break; /* Higher preferable */
2920a5143f2SDavid Howells }
2930a5143f2SDavid Howells
2940a5143f2SDavid Howells if (j < vllist->nr_servers) {
2950a5143f2SDavid Howells memmove(vllist->servers + j + 1,
2960a5143f2SDavid Howells vllist->servers + j,
2970a5143f2SDavid Howells (vllist->nr_servers - j) * sizeof(struct afs_vlserver_entry));
2980a5143f2SDavid Howells }
2990a5143f2SDavid Howells
3003bf0fb6fSDavid Howells clear_bit(AFS_VLSERVER_FL_PROBED, &server->flags);
3013bf0fb6fSDavid Howells
3020a5143f2SDavid Howells vllist->servers[j].priority = bs.priority;
3030a5143f2SDavid Howells vllist->servers[j].weight = bs.weight;
3040a5143f2SDavid Howells vllist->servers[j].server = server;
3050a5143f2SDavid Howells vllist->nr_servers++;
3060a5143f2SDavid Howells }
3070a5143f2SDavid Howells
3080a5143f2SDavid Howells if (b != end) {
3090a5143f2SDavid Howells _debug("parse error %zd", b - end);
3100a5143f2SDavid Howells goto error;
3110a5143f2SDavid Howells }
3120a5143f2SDavid Howells
3130a5143f2SDavid Howells afs_put_vlserverlist(cell->net, previous);
3140a5143f2SDavid Howells _leave(" = ok [%u]", vllist->nr_servers);
3150a5143f2SDavid Howells return vllist;
3160a5143f2SDavid Howells
3170a5143f2SDavid Howells error_2:
3180a5143f2SDavid Howells afs_put_vlserver(cell->net, server);
3190a5143f2SDavid Howells error:
3200a5143f2SDavid Howells afs_put_vlserverlist(cell->net, vllist);
3210a5143f2SDavid Howells afs_put_vlserverlist(cell->net, previous);
3220a5143f2SDavid Howells dump:
3230a5143f2SDavid Howells if (ret != -ENOMEM) {
3240a5143f2SDavid Howells printk(KERN_DEBUG "DNS: at %zu\n", (const void *)b - buffer);
3250a5143f2SDavid Howells print_hex_dump_bytes("DNS: ", DUMP_PREFIX_NONE, buffer, buffer_size);
3260a5143f2SDavid Howells }
3270a5143f2SDavid Howells return ERR_PTR(ret);
3280a5143f2SDavid Howells }
329