393 lines
8.6 KiB
C
393 lines
8.6 KiB
C
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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 (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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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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//#define AFS_MAX_ADDRESSES
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// ((unsigned int)((PAGE_SIZE - sizeof(struct afs_addr_list)) /
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// sizeof(struct sockaddr_rxrpc)))
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#define AFS_MAX_ADDRESSES ((unsigned int)(sizeof(unsigned long) * 8))
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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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call_rcu(&alist->rcu, (rcu_callback_t)kfree);
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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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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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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_addr_list *afs_parse_text_addrs(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_addr_list *alist;
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const char *p, *end = text + len;
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unsigned int nr = 0;
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_enter("%*.*s,%c", (int)len, (int)len, text, delim);
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if (!len)
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return ERR_PTR(-EDESTADDRREQ);
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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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return ERR_PTR(-EINVAL);
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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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return ERR_PTR(-EINVAL);
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p = memchr(p, ']', end - p);
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if (!p)
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return ERR_PTR(-EINVAL);
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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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if (nr > AFS_MAX_ADDRESSES)
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nr = AFS_MAX_ADDRESSES;
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alist = afs_alloc_addrlist(nr, service, port);
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if (!alist)
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return ERR_PTR(-ENOMEM);
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/* Extract the addresses */
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p = text;
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do {
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struct sockaddr_rxrpc *srx = &alist->addrs[alist->nr_addrs];
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const char *q, *stop;
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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,
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(u8 *)&srx->transport.sin6.sin6_addr.s6_addr32[3],
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-1, &stop)) {
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srx->transport.sin6.sin6_addr.s6_addr32[0] = 0;
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srx->transport.sin6.sin6_addr.s6_addr32[1] = 0;
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srx->transport.sin6.sin6_addr.s6_addr32[2] = htonl(0xffff);
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} else if (in6_pton(p, q - p,
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srx->transport.sin6.sin6_addr.s6_addr,
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-1, &stop)) {
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/* Nothing to do */
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} else {
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goto bad_address;
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}
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if (stop != q)
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goto bad_address;
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p = q;
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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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unsigned int xport = 0;
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p++;
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if (p >= end || !isdigit(*p))
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goto bad_address;
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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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goto bad_address;
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p++;
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} while (p < end && isdigit(*p));
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srx->transport.sin6.sin6_port = htons(xport);
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} else if (*p == delim) {
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p++;
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} else {
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goto bad_address;
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}
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}
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alist->nr_addrs++;
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} while (p < end && alist->nr_addrs < AFS_MAX_ADDRESSES);
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_leave(" = [nr %u]", alist->nr_addrs);
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return alist;
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bad_address:
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kfree(alist);
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return ERR_PTR(-EINVAL);
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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_addr_list *afs_dns_query(struct afs_cell *cell, time64_t *_expiry)
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{
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struct afs_addr_list *alist;
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char *vllist = NULL;
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int ret;
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_enter("%s", cell->name);
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ret = dns_query("afsdb", cell->name, cell->name_len,
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"", &vllist, _expiry);
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if (ret < 0)
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return ERR_PTR(ret);
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alist = afs_parse_text_addrs(vllist, strlen(vllist), ',',
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VL_SERVICE, AFS_VL_PORT);
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if (IS_ERR(alist)) {
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kfree(vllist);
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if (alist != ERR_PTR(-ENOMEM))
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pr_err("Failed to parse DNS data\n");
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return alist;
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}
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kfree(vllist);
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return alist;
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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_in6 *a;
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__be16 xport = htons(port);
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int i;
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for (i = 0; i < alist->nr_ipv4; i++) {
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a = &alist->addrs[i].transport.sin6;
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if (xdr == a->sin6_addr.s6_addr32[3] &&
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xport == a->sin6_port)
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return;
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if (xdr == a->sin6_addr.s6_addr32[3] &&
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(u16 __force)xport < (u16 __force)a->sin6_port)
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break;
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if ((u32 __force)xdr < (u32 __force)a->sin6_addr.s6_addr32[3])
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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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a = &alist->addrs[i].transport.sin6;
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a->sin6_port = xport;
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a->sin6_addr.s6_addr32[0] = 0;
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a->sin6_addr.s6_addr32[1] = 0;
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a->sin6_addr.s6_addr32[2] = htonl(0xffff);
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a->sin6_addr.s6_addr32[3] = 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_in6 *a;
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__be16 xport = htons(port);
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int i, diff;
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for (i = alist->nr_ipv4; i < alist->nr_addrs; i++) {
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a = &alist->addrs[i].transport.sin6;
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diff = memcmp(xdr, &a->sin6_addr, 16);
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if (diff == 0 &&
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xport == a->sin6_port)
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return;
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if (diff == 0 &&
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(u16 __force)xport < (u16 __force)a->sin6_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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a = &alist->addrs[i].transport.sin6;
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a->sin6_port = xport;
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a->sin6_addr.s6_addr32[0] = xdr[0];
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a->sin6_addr.s6_addr32[1] = xdr[1];
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a->sin6_addr.s6_addr32[2] = xdr[2];
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a->sin6_addr.s6_addr32[3] = xdr[3];
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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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_enter("%hu+%hd", ac->start, (short)ac->index);
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if (!ac->alist)
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return false;
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if (ac->begun) {
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ac->index++;
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if (ac->index == ac->alist->nr_addrs)
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ac->index = 0;
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if (ac->index == ac->start) {
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ac->error = -EDESTADDRREQ;
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return false;
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}
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}
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ac->begun = true;
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ac->responded = false;
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ac->addr = &ac->alist->addrs[ac->index];
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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 && ac->index != ac->start)
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WRITE_ONCE(alist->index, ac->index);
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afs_put_addrlist(alist);
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}
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ac->addr = NULL;
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ac->alist = NULL;
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ac->begun = false;
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return ac->error;
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}
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/*
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* Set the address cursor for iterating over VL servers.
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*/
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int afs_set_vl_cursor(struct afs_addr_cursor *ac, struct afs_cell *cell)
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{
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struct afs_addr_list *alist;
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int ret;
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if (!rcu_access_pointer(cell->vl_addrs)) {
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ret = wait_on_bit(&cell->flags, AFS_CELL_FL_NO_LOOKUP_YET,
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TASK_INTERRUPTIBLE);
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if (ret < 0)
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return ret;
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if (!rcu_access_pointer(cell->vl_addrs) &&
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ktime_get_real_seconds() < cell->dns_expiry)
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return cell->error;
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}
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read_lock(&cell->vl_addrs_lock);
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alist = rcu_dereference_protected(cell->vl_addrs,
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lockdep_is_held(&cell->vl_addrs_lock));
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if (alist->nr_addrs > 0)
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afs_get_addrlist(alist);
|
||
|
|
else
|
||
|
|
alist = NULL;
|
||
|
|
read_unlock(&cell->vl_addrs_lock);
|
||
|
|
|
||
|
|
if (!alist)
|
||
|
|
return -EDESTADDRREQ;
|
||
|
|
|
||
|
|
ac->alist = alist;
|
||
|
|
ac->addr = NULL;
|
||
|
|
ac->start = READ_ONCE(alist->index);
|
||
|
|
ac->index = ac->start;
|
||
|
|
ac->error = 0;
|
||
|
|
ac->begun = false;
|
||
|
|
return 0;
|
||
|
|
}
|