diff options
Diffstat (limited to 'fs/afs/addr_list.c')
| -rw-r--r-- | fs/afs/addr_list.c | 414 |
1 files changed, 414 insertions, 0 deletions
diff --git a/fs/afs/addr_list.c b/fs/afs/addr_list.c new file mode 100644 index 000000000000..e941da5b6dd9 --- /dev/null +++ b/fs/afs/addr_list.c @@ -0,0 +1,414 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Server address list management + * + * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include <linux/slab.h> +#include <linux/ctype.h> +#include <linux/dns_resolver.h> +#include <linux/inet.h> +#include <keys/rxrpc-type.h> +#include "internal.h" +#include "afs_fs.h" + +static void afs_free_addrlist(struct rcu_head *rcu) +{ + struct afs_addr_list *alist = container_of(rcu, struct afs_addr_list, rcu); + unsigned int i; + + for (i = 0; i < alist->nr_addrs; i++) + rxrpc_kernel_put_peer(alist->addrs[i].peer); + trace_afs_alist(alist->debug_id, refcount_read(&alist->usage), afs_alist_trace_free); + kfree(alist); +} + +/* + * Release an address list. + */ +void afs_put_addrlist(struct afs_addr_list *alist, enum afs_alist_trace reason) +{ + unsigned int debug_id; + bool dead; + int r; + + if (!alist) + return; + debug_id = alist->debug_id; + dead = __refcount_dec_and_test(&alist->usage, &r); + trace_afs_alist(debug_id, r - 1, reason); + if (dead) + call_rcu(&alist->rcu, afs_free_addrlist); +} + +struct afs_addr_list *afs_get_addrlist(struct afs_addr_list *alist, enum afs_alist_trace reason) +{ + int r; + + if (alist) { + __refcount_inc(&alist->usage, &r); + trace_afs_alist(alist->debug_id, r + 1, reason); + } + return alist; +} + +/* + * Allocate an address list. + */ +struct afs_addr_list *afs_alloc_addrlist(unsigned int nr) +{ + struct afs_addr_list *alist; + static atomic_t debug_id; + + _enter("%u", nr); + + if (nr > AFS_MAX_ADDRESSES) + nr = AFS_MAX_ADDRESSES; + + alist = kzalloc(struct_size(alist, addrs, nr), GFP_KERNEL); + if (!alist) + return NULL; + + refcount_set(&alist->usage, 1); + alist->max_addrs = nr; + alist->debug_id = atomic_inc_return(&debug_id); + trace_afs_alist(alist->debug_id, 1, afs_alist_trace_alloc); + return alist; +} + +/* + * Parse a text string consisting of delimited addresses. + */ +struct afs_vlserver_list *afs_parse_text_addrs(struct afs_net *net, + const char *text, size_t len, + char delim, + unsigned short service, + unsigned short port) +{ + struct afs_vlserver_list *vllist; + struct afs_addr_list *alist; + const char *p, *end = text + len; + const char *problem; + unsigned int nr = 0; + int ret = -ENOMEM; + + _enter("%*.*s,%c", (int)len, (int)len, text, delim); + + if (!len) { + _leave(" = -EDESTADDRREQ [empty]"); + return ERR_PTR(-EDESTADDRREQ); + } + + if (delim == ':' && (memchr(text, ',', len) || !memchr(text, '.', len))) + delim = ','; + + /* Count the addresses */ + p = text; + do { + if (!*p) { + problem = "nul"; + goto inval; + } + if (*p == delim) + continue; + nr++; + if (*p == '[') { + p++; + if (p == end) { + problem = "brace1"; + goto inval; + } + p = memchr(p, ']', end - p); + if (!p) { + problem = "brace2"; + goto inval; + } + p++; + if (p >= end) + break; + } + + p = memchr(p, delim, end - p); + if (!p) + break; + p++; + } while (p < end); + + _debug("%u/%u addresses", nr, AFS_MAX_ADDRESSES); + + vllist = afs_alloc_vlserver_list(1); + if (!vllist) + return ERR_PTR(-ENOMEM); + + vllist->nr_servers = 1; + vllist->servers[0].server = afs_alloc_vlserver("<dummy>", 7, AFS_VL_PORT); + if (!vllist->servers[0].server) + goto error_vl; + + alist = afs_alloc_addrlist(nr); + if (!alist) + goto error; + + /* Extract the addresses */ + p = text; + do { + const char *q, *stop; + unsigned int xport = port; + __be32 x[4]; + int family; + + if (*p == delim) { + p++; + continue; + } + + if (*p == '[') { + p++; + q = memchr(p, ']', end - p); + } else { + for (q = p; q < end; q++) + if (*q == '+' || *q == delim) + break; + } + + if (in4_pton(p, q - p, (u8 *)&x[0], -1, &stop)) { + family = AF_INET; + } else if (in6_pton(p, q - p, (u8 *)x, -1, &stop)) { + family = AF_INET6; + } else { + problem = "family"; + goto bad_address; + } + + p = q; + if (stop != p) { + problem = "nostop"; + goto bad_address; + } + + if (q < end && *q == ']') + p++; + + if (p < end) { + if (*p == '+') { + /* Port number specification "+1234" */ + xport = 0; + p++; + if (p >= end || !isdigit(*p)) { + problem = "port"; + goto bad_address; + } + do { + xport *= 10; + xport += *p - '0'; + if (xport > 65535) { + problem = "pval"; + goto bad_address; + } + p++; + } while (p < end && isdigit(*p)); + } else if (*p == delim) { + p++; + } else { + problem = "weird"; + goto bad_address; + } + } + + if (family == AF_INET) + ret = afs_merge_fs_addr4(net, alist, x[0], xport); + else + ret = afs_merge_fs_addr6(net, alist, x, xport); + if (ret < 0) + goto error; + + } while (p < end); + + rcu_assign_pointer(vllist->servers[0].server->addresses, alist); + _leave(" = [nr %u]", alist->nr_addrs); + return vllist; + +inval: + _leave(" = -EINVAL [%s %zu %*.*s]", + problem, p - text, (int)len, (int)len, text); + return ERR_PTR(-EINVAL); +bad_address: + _leave(" = -EINVAL [%s %zu %*.*s]", + problem, p - text, (int)len, (int)len, text); + ret = -EINVAL; +error: + afs_put_addrlist(alist, afs_alist_trace_put_parse_error); +error_vl: + afs_put_vlserverlist(net, vllist); + return ERR_PTR(ret); +} + +/* + * Perform a DNS query for VL servers and build a up an address list. + */ +struct afs_vlserver_list *afs_dns_query(struct afs_cell *cell, time64_t *_expiry) +{ + struct afs_vlserver_list *vllist; + char *result = NULL; + int ret; + + _enter("%s", cell->name); + + ret = dns_query(cell->net->net, "afsdb", cell->name, cell->name_len, + "srv=1", &result, _expiry, true); + if (ret < 0) { + _leave(" = %d [dns]", ret); + return ERR_PTR(ret); + } + + if (*_expiry == 0) + *_expiry = ktime_get_real_seconds() + 60; + + if (ret > 1 && result[0] == 0) + vllist = afs_extract_vlserver_list(cell, result, ret); + else + vllist = afs_parse_text_addrs(cell->net, result, ret, ',', + VL_SERVICE, AFS_VL_PORT); + kfree(result); + if (IS_ERR(vllist) && vllist != ERR_PTR(-ENOMEM)) + pr_err("Failed to parse DNS data %ld\n", PTR_ERR(vllist)); + + return vllist; +} + +/* + * Merge an IPv4 entry into a fileserver address list. + */ +int afs_merge_fs_addr4(struct afs_net *net, struct afs_addr_list *alist, + __be32 xdr, u16 port) +{ + struct sockaddr_rxrpc srx; + struct rxrpc_peer *peer; + int i; + + if (alist->nr_addrs >= alist->max_addrs) + return 0; + + srx.srx_family = AF_RXRPC; + srx.transport_type = SOCK_DGRAM; + srx.transport_len = sizeof(srx.transport.sin); + srx.transport.sin.sin_family = AF_INET; + srx.transport.sin.sin_port = htons(port); + srx.transport.sin.sin_addr.s_addr = xdr; + + peer = rxrpc_kernel_lookup_peer(net->socket, &srx, GFP_KERNEL); + if (!peer) + return -ENOMEM; + + for (i = 0; i < alist->nr_ipv4; i++) { + if (peer == alist->addrs[i].peer) { + rxrpc_kernel_put_peer(peer); + return 0; + } + if (peer <= alist->addrs[i].peer) + break; + } + + if (i < alist->nr_addrs) + memmove(alist->addrs + i + 1, + alist->addrs + i, + sizeof(alist->addrs[0]) * (alist->nr_addrs - i)); + + alist->addrs[i].peer = peer; + alist->nr_ipv4++; + alist->nr_addrs++; + return 0; +} + +/* + * Merge an IPv6 entry into a fileserver address list. + */ +int afs_merge_fs_addr6(struct afs_net *net, struct afs_addr_list *alist, + __be32 *xdr, u16 port) +{ + struct sockaddr_rxrpc srx; + struct rxrpc_peer *peer; + int i; + + if (alist->nr_addrs >= alist->max_addrs) + return 0; + + srx.srx_family = AF_RXRPC; + srx.transport_type = SOCK_DGRAM; + srx.transport_len = sizeof(srx.transport.sin6); + srx.transport.sin6.sin6_family = AF_INET6; + srx.transport.sin6.sin6_port = htons(port); + memcpy(&srx.transport.sin6.sin6_addr, xdr, 16); + + peer = rxrpc_kernel_lookup_peer(net->socket, &srx, GFP_KERNEL); + if (!peer) + return -ENOMEM; + + for (i = alist->nr_ipv4; i < alist->nr_addrs; i++) { + if (peer == alist->addrs[i].peer) { + rxrpc_kernel_put_peer(peer); + return 0; + } + if (peer <= alist->addrs[i].peer) + break; + } + + if (i < alist->nr_addrs) + memmove(alist->addrs + i + 1, + alist->addrs + i, + sizeof(alist->addrs[0]) * (alist->nr_addrs - i)); + alist->addrs[i].peer = peer; + alist->nr_addrs++; + return 0; +} + +/* + * Set the app data on the rxrpc peers an address list points to + */ +void afs_set_peer_appdata(struct afs_server *server, + struct afs_addr_list *old_alist, + struct afs_addr_list *new_alist) +{ + unsigned long data = (unsigned long)server; + int n = 0, o = 0; + + if (!old_alist) { + /* New server. Just set all. */ + for (; n < new_alist->nr_addrs; n++) + rxrpc_kernel_set_peer_data(new_alist->addrs[n].peer, data); + return; + } + if (!new_alist) { + /* Dead server. Just remove all. */ + for (; o < old_alist->nr_addrs; o++) + rxrpc_kernel_set_peer_data(old_alist->addrs[o].peer, 0); + return; + } + + /* Walk through the two lists simultaneously, setting new peers and + * clearing old ones. The two lists are ordered by pointer to peer + * record. + */ + while (n < new_alist->nr_addrs && o < old_alist->nr_addrs) { + struct rxrpc_peer *pn = new_alist->addrs[n].peer; + struct rxrpc_peer *po = old_alist->addrs[o].peer; + + if (pn == po) + continue; + if (pn < po) { + rxrpc_kernel_set_peer_data(pn, data); + n++; + } else { + rxrpc_kernel_set_peer_data(po, 0); + o++; + } + } + + if (n < new_alist->nr_addrs) + for (; n < new_alist->nr_addrs; n++) + rxrpc_kernel_set_peer_data(new_alist->addrs[n].peer, data); + if (o < old_alist->nr_addrs) + for (; o < old_alist->nr_addrs; o++) + rxrpc_kernel_set_peer_data(old_alist->addrs[o].peer, 0); +} |