fs/afs/addr_list.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* Server address list management
   3  *
   4  * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
   5  * Written by David Howells (dhowells@redhat.com)
   6  */
   7
   8 #include <linux/slab.h>
   9 #include <linux/ctype.h>
  10 #include <linux/dns_resolver.h>
  11 #include <linux/inet.h>
  12 #include <keys/rxrpc-type.h>
  13 #include "internal.h"
  14 #include "afs_fs.h"
  15
  16 static void afs_free_addrlist(struct rcu_head *rcu)
  17 {
  18         struct afs_addr_list *alist = container_of(rcu, struct afs_addr_list, rcu);
  19         unsigned int i;
  20
  21         for (i = 0; i < alist->nr_addrs; i++)
  22                 rxrpc_kernel_put_peer(alist->addrs[i].peer);
  23         trace_afs_alist(alist->debug_id, refcount_read(&alist->usage), afs_alist_trace_free);
  24         kfree(alist);
  25 }
  26
  27 /*
  28  * Release an address list.
  29  */
  30 void afs_put_addrlist(struct afs_addr_list *alist, enum afs_alist_trace reason)
  31 {
  32         unsigned int debug_id;
  33         bool dead;
  34         int r;
  35
  36         if (!alist)
  37                 return;
  38         debug_id = alist->debug_id;
  39         dead = __refcount_dec_and_test(&alist->usage, &r);
  40         trace_afs_alist(debug_id, r - 1, reason);
  41         if (dead)
  42                 call_rcu(&alist->rcu, afs_free_addrlist);
  43 }
  44
  45 struct afs_addr_list *afs_get_addrlist(struct afs_addr_list *alist, enum afs_alist_trace reason)
  46 {
  47         int r;
  48
  49         if (alist) {
  50                 __refcount_inc(&alist->usage, &r);
  51                 trace_afs_alist(alist->debug_id, r + 1, reason);
  52         }
  53         return alist;
  54 }
  55
  56 /*
  57  * Allocate an address list.
  58  */
  59 struct afs_addr_list *afs_alloc_addrlist(unsigned int nr)
  60 {
  61         struct afs_addr_list *alist;
  62         static atomic_t debug_id;
  63
  64         _enter("%u", nr);
  65
  66         if (nr > AFS_MAX_ADDRESSES)
  67                 nr = AFS_MAX_ADDRESSES;
  68
  69         alist = kzalloc(struct_size(alist, addrs, nr), GFP_KERNEL);
  70         if (!alist)
  71                 return NULL;
  72
  73         refcount_set(&alist->usage, 1);
  74         alist->max_addrs = nr;
  75         alist->debug_id = atomic_inc_return(&debug_id);
  76         trace_afs_alist(alist->debug_id, 1, afs_alist_trace_alloc);
  77         return alist;
  78 }
  79
  80 /*
  81  * Parse a text string consisting of delimited addresses.
  82  */
  83 struct afs_vlserver_list *afs_parse_text_addrs(struct afs_net *net,
  84                                                const char *text, size_t len,
  85                                                char delim,
  86                                                unsigned short service,
  87                                                unsigned short port)
  88 {
  89         struct afs_vlserver_list *vllist;
  90         struct afs_addr_list *alist;
  91         const char *p, *end = text + len;
  92         const char *problem;
  93         unsigned int nr = 0;
  94         int ret = -ENOMEM;
  95
  96         _enter("%*.*s,%c", (int)len, (int)len, text, delim);
  97
  98         if (!len) {
  99                 _leave(" = -EDESTADDRREQ [empty]");
 100                 return ERR_PTR(-EDESTADDRREQ);
 101         }
 102
 103         if (delim == ':' && (memchr(text, ',', len) || !memchr(text, '.', len)))
 104                 delim = ',';
 105
 106         /* Count the addresses */
 107         p = text;
 108         do {
 109                 if (!*p) {
 110                         problem = "nul";
 111                         goto inval;
 112                 }
 113                 if (*p == delim)
 114                         continue;
 115                 nr++;
 116                 if (*p == '[') {
 117                         p++;
 118                         if (p == end) {
 119                                 problem = "brace1";
 120                                 goto inval;
 121                         }
 122                         p = memchr(p, ']', end - p);
 123                         if (!p) {
 124                                 problem = "brace2";
 125                                 goto inval;
 126                         }
 127                         p++;
 128                         if (p >= end)
 129                                 break;
 130                 }
 131
 132                 p = memchr(p, delim, end - p);
 133                 if (!p)
 134                         break;
 135                 p++;
 136         } while (p < end);
 137
 138         _debug("%u/%u addresses", nr, AFS_MAX_ADDRESSES);
 139
 140         vllist = afs_alloc_vlserver_list(1);
 141         if (!vllist)
 142                 return ERR_PTR(-ENOMEM);
 143
 144         vllist->nr_servers = 1;
 145         vllist->servers[0].server = afs_alloc_vlserver("<dummy>", 7, AFS_VL_PORT);
 146         if (!vllist->servers[0].server)
 147                 goto error_vl;
 148
 149         alist = afs_alloc_addrlist(nr);
 150         if (!alist)
 151                 goto error;
 152
 153         /* Extract the addresses */
 154         p = text;
 155         do {
 156                 const char *q, *stop;
 157                 unsigned int xport = port;
 158                 __be32 x[4];
 159                 int family;
 160
 161                 if (*p == delim) {
 162                         p++;
 163                         continue;
 164                 }
 165
 166                 if (*p == '[') {
 167                         p++;
 168                         q = memchr(p, ']', end - p);
 169                 } else {
 170                         for (q = p; q < end; q++)
 171                                 if (*q == '+' || *q == delim)
 172                                         break;
 173                 }
 174
 175                 if (in4_pton(p, q - p, (u8 *)&x[0], -1, &stop)) {
 176                         family = AF_INET;
 177                 } else if (in6_pton(p, q - p, (u8 *)x, -1, &stop)) {
 178                         family = AF_INET6;
 179                 } else {
 180                         problem = "family";
 181                         goto bad_address;
 182                 }
 183
 184                 p = q;
 185                 if (stop != p) {
 186                         problem = "nostop";
 187                         goto bad_address;
 188                 }
 189
 190                 if (q < end && *q == ']')
 191                         p++;
 192
 193                 if (p < end) {
 194                         if (*p == '+') {
 195                                 /* Port number specification "+1234" */
 196                                 xport = 0;
 197                                 p++;
 198                                 if (p >= end || !isdigit(*p)) {
 199                                         problem = "port";
 200                                         goto bad_address;
 201                                 }
 202                                 do {
 203                                         xport *= 10;
 204                                         xport += *p - '0';
 205                                         if (xport > 65535) {
 206                                                 problem = "pval";
 207                                                 goto bad_address;
 208                                         }
 209                                         p++;
 210                                 } while (p < end && isdigit(*p));
 211                         } else if (*p == delim) {
 212                                 p++;
 213                         } else {
 214                                 problem = "weird";
 215                                 goto bad_address;
 216                         }
 217                 }
 218
 219                 if (family == AF_INET)
 220                         ret = afs_merge_fs_addr4(net, alist, x[0], xport);
 221                 else
 222                         ret = afs_merge_fs_addr6(net, alist, x, xport);
 223                 if (ret < 0)
 224                         goto error;
 225
 226         } while (p < end);
 227
 228         rcu_assign_pointer(vllist->servers[0].server->addresses, alist);
 229         _leave(" = [nr %u]", alist->nr_addrs);
 230         return vllist;
 231
 232 inval:
 233         _leave(" = -EINVAL [%s %zu %*.*s]",
 234                problem, p - text, (int)len, (int)len, text);
 235         return ERR_PTR(-EINVAL);
 236 bad_address:
 237         _leave(" = -EINVAL [%s %zu %*.*s]",
 238                problem, p - text, (int)len, (int)len, text);
 239         ret = -EINVAL;
 240 error:
 241         afs_put_addrlist(alist, afs_alist_trace_put_parse_error);
 242 error_vl:
 243         afs_put_vlserverlist(net, vllist);
 244         return ERR_PTR(ret);
 245 }
 246
 247 /*
 248  * Perform a DNS query for VL servers and build a up an address list.
 249  */
 250 struct afs_vlserver_list *afs_dns_query(struct afs_cell *cell, time64_t *_expiry)
 251 {
 252         struct afs_vlserver_list *vllist;
 253         char *result = NULL;
 254         int ret;
 255
 256         _enter("%s", cell->name);
 257
 258         ret = dns_query(cell->net->net, "afsdb", cell->name, cell->name_len,
 259                         "srv=1", &result, _expiry, true);
 260         if (ret < 0) {
 261                 _leave(" = %d [dns]", ret);
 262                 return ERR_PTR(ret);
 263         }
 264
 265         if (*_expiry == 0)
 266                 *_expiry = ktime_get_real_seconds() + 60;
 267
 268         if (ret > 1 && result[0] == 0)
 269                 vllist = afs_extract_vlserver_list(cell, result, ret);
 270         else
 271                 vllist = afs_parse_text_addrs(cell->net, result, ret, ',',
 272                                               VL_SERVICE, AFS_VL_PORT);
 273         kfree(result);
 274         if (IS_ERR(vllist) && vllist != ERR_PTR(-ENOMEM))
 275                 pr_err("Failed to parse DNS data %ld\n", PTR_ERR(vllist));
 276
 277         return vllist;
 278 }
 279
 280 /*
 281  * Merge an IPv4 entry into a fileserver address list.
 282  */
 283 int afs_merge_fs_addr4(struct afs_net *net, struct afs_addr_list *alist,
 284                        __be32 xdr, u16 port)
 285 {
 286         struct sockaddr_rxrpc srx;
 287         struct rxrpc_peer *peer;
 288         int i;
 289
 290         if (alist->nr_addrs >= alist->max_addrs)
 291                 return 0;
 292
 293         srx.srx_family = AF_RXRPC;
 294         srx.transport_type = SOCK_DGRAM;
 295         srx.transport_len = sizeof(srx.transport.sin);
 296         srx.transport.sin.sin_family = AF_INET;
 297         srx.transport.sin.sin_port = htons(port);
 298         srx.transport.sin.sin_addr.s_addr = xdr;
 299
 300         peer = rxrpc_kernel_lookup_peer(net->socket, &srx, GFP_KERNEL);
 301         if (!peer)
 302                 return -ENOMEM;
 303
 304         for (i = 0; i < alist->nr_ipv4; i++) {
 305                 if (peer == alist->addrs[i].peer) {
 306                         rxrpc_kernel_put_peer(peer);
 307                         return 0;
 308                 }
 309                 if (peer <= alist->addrs[i].peer)
 310                         break;
 311         }
 312
 313         if (i < alist->nr_addrs)
 314                 memmove(alist->addrs + i + 1,
 315                         alist->addrs + i,
 316                         sizeof(alist->addrs[0]) * (alist->nr_addrs - i));
 317
 318         alist->addrs[i].peer = peer;
 319         alist->nr_ipv4++;
 320         alist->nr_addrs++;
 321         return 0;
 322 }
 323
 324 /*
 325  * Merge an IPv6 entry into a fileserver address list.
 326  */
 327 int afs_merge_fs_addr6(struct afs_net *net, struct afs_addr_list *alist,
 328                        __be32 *xdr, u16 port)
 329 {
 330         struct sockaddr_rxrpc srx;
 331         struct rxrpc_peer *peer;
 332         int i;
 333
 334         if (alist->nr_addrs >= alist->max_addrs)
 335                 return 0;
 336
 337         srx.srx_family = AF_RXRPC;
 338         srx.transport_type = SOCK_DGRAM;
 339         srx.transport_len = sizeof(srx.transport.sin6);
 340         srx.transport.sin6.sin6_family = AF_INET6;
 341         srx.transport.sin6.sin6_port = htons(port);
 342         memcpy(&srx.transport.sin6.sin6_addr, xdr, 16);
 343
 344         peer = rxrpc_kernel_lookup_peer(net->socket, &srx, GFP_KERNEL);
 345         if (!peer)
 346                 return -ENOMEM;
 347
 348         for (i = alist->nr_ipv4; i < alist->nr_addrs; i++) {
 349                 if (peer == alist->addrs[i].peer) {
 350                         rxrpc_kernel_put_peer(peer);
 351                         return 0;
 352                 }
 353                 if (peer <= alist->addrs[i].peer)
 354                         break;
 355         }
 356
 357         if (i < alist->nr_addrs)
 358                 memmove(alist->addrs + i + 1,
 359                         alist->addrs + i,
 360                         sizeof(alist->addrs[0]) * (alist->nr_addrs - i));
 361         alist->addrs[i].peer = peer;
 362         alist->nr_addrs++;
 363         return 0;
 364 }