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404 lines
8.5 KiB
404 lines
8.5 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* Server address list management |
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* |
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* Copyright (C) 2017 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/slab.h> |
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#include <linux/ctype.h> |
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#include <linux/dns_resolver.h> |
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#include <linux/inet.h> |
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#include <keys/rxrpc-type.h> |
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#include "internal.h" |
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#include "afs_fs.h" |
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/* |
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* Release an address list. |
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*/ |
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void afs_put_addrlist(struct afs_addr_list *alist) |
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{ |
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if (alist && refcount_dec_and_test(&alist->usage)) |
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kfree_rcu(alist, rcu); |
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} |
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/* |
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* Allocate an address list. |
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*/ |
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struct afs_addr_list *afs_alloc_addrlist(unsigned int nr, |
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unsigned short service, |
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unsigned short port) |
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{ |
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struct afs_addr_list *alist; |
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unsigned int i; |
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_enter("%u,%u,%u", nr, service, port); |
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if (nr > AFS_MAX_ADDRESSES) |
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nr = AFS_MAX_ADDRESSES; |
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alist = kzalloc(struct_size(alist, addrs, nr), GFP_KERNEL); |
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if (!alist) |
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return NULL; |
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refcount_set(&alist->usage, 1); |
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alist->max_addrs = nr; |
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for (i = 0; i < nr; i++) { |
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struct sockaddr_rxrpc *srx = &alist->addrs[i]; |
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srx->srx_family = AF_RXRPC; |
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srx->srx_service = service; |
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srx->transport_type = SOCK_DGRAM; |
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srx->transport_len = sizeof(srx->transport.sin6); |
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srx->transport.sin6.sin6_family = AF_INET6; |
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srx->transport.sin6.sin6_port = htons(port); |
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} |
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return alist; |
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} |
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/* |
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* Parse a text string consisting of delimited addresses. |
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*/ |
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struct afs_vlserver_list *afs_parse_text_addrs(struct afs_net *net, |
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const char *text, size_t len, |
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char delim, |
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unsigned short service, |
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unsigned short port) |
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{ |
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struct afs_vlserver_list *vllist; |
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struct afs_addr_list *alist; |
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const char *p, *end = text + len; |
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const char *problem; |
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unsigned int nr = 0; |
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int ret = -ENOMEM; |
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_enter("%*.*s,%c", (int)len, (int)len, text, delim); |
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if (!len) { |
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_leave(" = -EDESTADDRREQ [empty]"); |
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return ERR_PTR(-EDESTADDRREQ); |
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} |
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if (delim == ':' && (memchr(text, ',', len) || !memchr(text, '.', len))) |
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delim = ','; |
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/* Count the addresses */ |
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p = text; |
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do { |
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if (!*p) { |
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problem = "nul"; |
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goto inval; |
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} |
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if (*p == delim) |
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continue; |
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nr++; |
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if (*p == '[') { |
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p++; |
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if (p == end) { |
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problem = "brace1"; |
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goto inval; |
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} |
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p = memchr(p, ']', end - p); |
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if (!p) { |
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problem = "brace2"; |
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goto inval; |
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} |
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p++; |
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if (p >= end) |
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break; |
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} |
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p = memchr(p, delim, end - p); |
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if (!p) |
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break; |
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p++; |
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} while (p < end); |
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_debug("%u/%u addresses", nr, AFS_MAX_ADDRESSES); |
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vllist = afs_alloc_vlserver_list(1); |
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if (!vllist) |
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return ERR_PTR(-ENOMEM); |
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vllist->nr_servers = 1; |
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vllist->servers[0].server = afs_alloc_vlserver("<dummy>", 7, AFS_VL_PORT); |
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if (!vllist->servers[0].server) |
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goto error_vl; |
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alist = afs_alloc_addrlist(nr, service, AFS_VL_PORT); |
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if (!alist) |
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goto error; |
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/* Extract the addresses */ |
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p = text; |
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do { |
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const char *q, *stop; |
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unsigned int xport = port; |
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__be32 x[4]; |
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int family; |
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if (*p == delim) { |
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p++; |
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continue; |
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} |
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if (*p == '[') { |
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p++; |
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q = memchr(p, ']', end - p); |
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} else { |
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for (q = p; q < end; q++) |
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if (*q == '+' || *q == delim) |
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break; |
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} |
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if (in4_pton(p, q - p, (u8 *)&x[0], -1, &stop)) { |
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family = AF_INET; |
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} else if (in6_pton(p, q - p, (u8 *)x, -1, &stop)) { |
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family = AF_INET6; |
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} else { |
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problem = "family"; |
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goto bad_address; |
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} |
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p = q; |
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if (stop != p) { |
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problem = "nostop"; |
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goto bad_address; |
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} |
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if (q < end && *q == ']') |
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p++; |
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if (p < end) { |
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if (*p == '+') { |
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/* Port number specification "+1234" */ |
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xport = 0; |
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p++; |
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if (p >= end || !isdigit(*p)) { |
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problem = "port"; |
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goto bad_address; |
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} |
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do { |
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xport *= 10; |
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xport += *p - '0'; |
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if (xport > 65535) { |
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problem = "pval"; |
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goto bad_address; |
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} |
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p++; |
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} while (p < end && isdigit(*p)); |
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} else if (*p == delim) { |
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p++; |
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} else { |
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problem = "weird"; |
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goto bad_address; |
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} |
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} |
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if (family == AF_INET) |
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afs_merge_fs_addr4(alist, x[0], xport); |
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else |
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afs_merge_fs_addr6(alist, x, xport); |
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} while (p < end); |
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rcu_assign_pointer(vllist->servers[0].server->addresses, alist); |
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_leave(" = [nr %u]", alist->nr_addrs); |
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return vllist; |
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inval: |
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_leave(" = -EINVAL [%s %zu %*.*s]", |
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problem, p - text, (int)len, (int)len, text); |
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return ERR_PTR(-EINVAL); |
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bad_address: |
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_leave(" = -EINVAL [%s %zu %*.*s]", |
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problem, p - text, (int)len, (int)len, text); |
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ret = -EINVAL; |
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error: |
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afs_put_addrlist(alist); |
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error_vl: |
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afs_put_vlserverlist(net, vllist); |
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return ERR_PTR(ret); |
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} |
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/* |
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* Compare old and new address lists to see if there's been any change. |
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* - How to do this in better than O(Nlog(N)) time? |
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* - We don't really want to sort the address list, but would rather take the |
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* list as we got it so as not to undo record rotation by the DNS server. |
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*/ |
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#if 0 |
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static int afs_cmp_addr_list(const struct afs_addr_list *a1, |
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const struct afs_addr_list *a2) |
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{ |
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} |
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#endif |
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/* |
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* Perform a DNS query for VL servers and build a up an address list. |
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*/ |
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struct afs_vlserver_list *afs_dns_query(struct afs_cell *cell, time64_t *_expiry) |
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{ |
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struct afs_vlserver_list *vllist; |
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char *result = NULL; |
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int ret; |
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_enter("%s", cell->name); |
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ret = dns_query(cell->net->net, "afsdb", cell->name, cell->name_len, |
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"srv=1", &result, _expiry, true); |
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if (ret < 0) { |
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_leave(" = %d [dns]", ret); |
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return ERR_PTR(ret); |
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} |
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if (*_expiry == 0) |
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*_expiry = ktime_get_real_seconds() + 60; |
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if (ret > 1 && result[0] == 0) |
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vllist = afs_extract_vlserver_list(cell, result, ret); |
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else |
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vllist = afs_parse_text_addrs(cell->net, result, ret, ',', |
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VL_SERVICE, AFS_VL_PORT); |
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kfree(result); |
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if (IS_ERR(vllist) && vllist != ERR_PTR(-ENOMEM)) |
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pr_err("Failed to parse DNS data %ld\n", PTR_ERR(vllist)); |
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return vllist; |
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} |
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/* |
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* Merge an IPv4 entry into a fileserver address list. |
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*/ |
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void afs_merge_fs_addr4(struct afs_addr_list *alist, __be32 xdr, u16 port) |
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{ |
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struct sockaddr_rxrpc *srx; |
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u32 addr = ntohl(xdr); |
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int i; |
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if (alist->nr_addrs >= alist->max_addrs) |
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return; |
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for (i = 0; i < alist->nr_ipv4; i++) { |
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struct sockaddr_in *a = &alist->addrs[i].transport.sin; |
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u32 a_addr = ntohl(a->sin_addr.s_addr); |
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u16 a_port = ntohs(a->sin_port); |
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if (addr == a_addr && port == a_port) |
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return; |
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if (addr == a_addr && port < a_port) |
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break; |
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if (addr < a_addr) |
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break; |
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} |
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if (i < alist->nr_addrs) |
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memmove(alist->addrs + i + 1, |
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alist->addrs + i, |
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sizeof(alist->addrs[0]) * (alist->nr_addrs - i)); |
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srx = &alist->addrs[i]; |
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srx->srx_family = AF_RXRPC; |
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srx->transport_type = SOCK_DGRAM; |
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srx->transport_len = sizeof(srx->transport.sin); |
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srx->transport.sin.sin_family = AF_INET; |
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srx->transport.sin.sin_port = htons(port); |
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srx->transport.sin.sin_addr.s_addr = xdr; |
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alist->nr_ipv4++; |
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alist->nr_addrs++; |
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} |
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/* |
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* Merge an IPv6 entry into a fileserver address list. |
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*/ |
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void afs_merge_fs_addr6(struct afs_addr_list *alist, __be32 *xdr, u16 port) |
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{ |
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struct sockaddr_rxrpc *srx; |
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int i, diff; |
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if (alist->nr_addrs >= alist->max_addrs) |
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return; |
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for (i = alist->nr_ipv4; i < alist->nr_addrs; i++) { |
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struct sockaddr_in6 *a = &alist->addrs[i].transport.sin6; |
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u16 a_port = ntohs(a->sin6_port); |
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diff = memcmp(xdr, &a->sin6_addr, 16); |
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if (diff == 0 && port == a_port) |
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return; |
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if (diff == 0 && port < a_port) |
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break; |
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if (diff < 0) |
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break; |
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} |
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if (i < alist->nr_addrs) |
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memmove(alist->addrs + i + 1, |
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alist->addrs + i, |
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sizeof(alist->addrs[0]) * (alist->nr_addrs - i)); |
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srx = &alist->addrs[i]; |
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srx->srx_family = AF_RXRPC; |
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srx->transport_type = SOCK_DGRAM; |
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srx->transport_len = sizeof(srx->transport.sin6); |
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srx->transport.sin6.sin6_family = AF_INET6; |
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srx->transport.sin6.sin6_port = htons(port); |
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memcpy(&srx->transport.sin6.sin6_addr, xdr, 16); |
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alist->nr_addrs++; |
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} |
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/* |
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* Get an address to try. |
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*/ |
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bool afs_iterate_addresses(struct afs_addr_cursor *ac) |
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{ |
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unsigned long set, failed; |
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int index; |
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if (!ac->alist) |
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return false; |
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set = ac->alist->responded; |
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failed = ac->alist->failed; |
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_enter("%lx-%lx-%lx,%d", set, failed, ac->tried, ac->index); |
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ac->nr_iterations++; |
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set &= ~(failed | ac->tried); |
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if (!set) |
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return false; |
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index = READ_ONCE(ac->alist->preferred); |
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if (test_bit(index, &set)) |
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goto selected; |
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index = __ffs(set); |
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selected: |
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ac->index = index; |
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set_bit(index, &ac->tried); |
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ac->responded = false; |
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return true; |
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} |
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/* |
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* Release an address list cursor. |
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*/ |
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int afs_end_cursor(struct afs_addr_cursor *ac) |
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{ |
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struct afs_addr_list *alist; |
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alist = ac->alist; |
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if (alist) { |
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if (ac->responded && |
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ac->index != alist->preferred && |
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test_bit(ac->alist->preferred, &ac->tried)) |
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WRITE_ONCE(alist->preferred, ac->index); |
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afs_put_addrlist(alist); |
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ac->alist = NULL; |
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} |
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return ac->error; |
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}
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