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-rw-r--r--fs/afs/addr_list.c404
1 files changed, 404 insertions, 0 deletions
diff --git a/fs/afs/addr_list.c b/fs/afs/addr_list.c
new file mode 100644
index 000000000..de1ae0bea
--- /dev/null
+++ b/fs/afs/addr_list.c
@@ -0,0 +1,404 @@
+// 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"
+
+/*
+ * Release an address list.
+ */
+void afs_put_addrlist(struct afs_addr_list *alist)
+{
+ if (alist && refcount_dec_and_test(&alist->usage))
+ kfree_rcu(alist, rcu);
+}
+
+/*
+ * Allocate an address list.
+ */
+struct afs_addr_list *afs_alloc_addrlist(unsigned int nr,
+ unsigned short service,
+ unsigned short port)
+{
+ struct afs_addr_list *alist;
+ unsigned int i;
+
+ _enter("%u,%u,%u", nr, service, port);
+
+ 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;
+
+ for (i = 0; i < nr; i++) {
+ struct sockaddr_rxrpc *srx = &alist->addrs[i];
+ srx->srx_family = AF_RXRPC;
+ srx->srx_service = service;
+ 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);
+ }
+
+ 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, service, AFS_VL_PORT);
+ 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)
+ afs_merge_fs_addr4(alist, x[0], xport);
+ else
+ afs_merge_fs_addr6(alist, x, xport);
+
+ } 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);
+error_vl:
+ afs_put_vlserverlist(net, vllist);
+ return ERR_PTR(ret);
+}
+
+/*
+ * Compare old and new address lists to see if there's been any change.
+ * - How to do this in better than O(Nlog(N)) time?
+ * - We don't really want to sort the address list, but would rather take the
+ * list as we got it so as not to undo record rotation by the DNS server.
+ */
+#if 0
+static int afs_cmp_addr_list(const struct afs_addr_list *a1,
+ const struct afs_addr_list *a2)
+{
+}
+#endif
+
+/*
+ * 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.
+ */
+void afs_merge_fs_addr4(struct afs_addr_list *alist, __be32 xdr, u16 port)
+{
+ struct sockaddr_rxrpc *srx;
+ u32 addr = ntohl(xdr);
+ int i;
+
+ if (alist->nr_addrs >= alist->max_addrs)
+ return;
+
+ for (i = 0; i < alist->nr_ipv4; i++) {
+ struct sockaddr_in *a = &alist->addrs[i].transport.sin;
+ u32 a_addr = ntohl(a->sin_addr.s_addr);
+ u16 a_port = ntohs(a->sin_port);
+
+ if (addr == a_addr && port == a_port)
+ return;
+ if (addr == a_addr && port < a_port)
+ break;
+ if (addr < a_addr)
+ break;
+ }
+
+ if (i < alist->nr_addrs)
+ memmove(alist->addrs + i + 1,
+ alist->addrs + i,
+ sizeof(alist->addrs[0]) * (alist->nr_addrs - i));
+
+ srx = &alist->addrs[i];
+ 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;
+ alist->nr_ipv4++;
+ alist->nr_addrs++;
+}
+
+/*
+ * Merge an IPv6 entry into a fileserver address list.
+ */
+void afs_merge_fs_addr6(struct afs_addr_list *alist, __be32 *xdr, u16 port)
+{
+ struct sockaddr_rxrpc *srx;
+ int i, diff;
+
+ if (alist->nr_addrs >= alist->max_addrs)
+ return;
+
+ for (i = alist->nr_ipv4; i < alist->nr_addrs; i++) {
+ struct sockaddr_in6 *a = &alist->addrs[i].transport.sin6;
+ u16 a_port = ntohs(a->sin6_port);
+
+ diff = memcmp(xdr, &a->sin6_addr, 16);
+ if (diff == 0 && port == a_port)
+ return;
+ if (diff == 0 && port < a_port)
+ break;
+ if (diff < 0)
+ break;
+ }
+
+ if (i < alist->nr_addrs)
+ memmove(alist->addrs + i + 1,
+ alist->addrs + i,
+ sizeof(alist->addrs[0]) * (alist->nr_addrs - i));
+
+ srx = &alist->addrs[i];
+ 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);
+ alist->nr_addrs++;
+}
+
+/*
+ * Get an address to try.
+ */
+bool afs_iterate_addresses(struct afs_addr_cursor *ac)
+{
+ unsigned long set, failed;
+ int index;
+
+ if (!ac->alist)
+ return false;
+
+ set = ac->alist->responded;
+ failed = ac->alist->failed;
+ _enter("%lx-%lx-%lx,%d", set, failed, ac->tried, ac->index);
+
+ ac->nr_iterations++;
+
+ set &= ~(failed | ac->tried);
+
+ if (!set)
+ return false;
+
+ index = READ_ONCE(ac->alist->preferred);
+ if (test_bit(index, &set))
+ goto selected;
+
+ index = __ffs(set);
+
+selected:
+ ac->index = index;
+ set_bit(index, &ac->tried);
+ ac->responded = false;
+ return true;
+}
+
+/*
+ * Release an address list cursor.
+ */
+int afs_end_cursor(struct afs_addr_cursor *ac)
+{
+ struct afs_addr_list *alist;
+
+ alist = ac->alist;
+ if (alist) {
+ if (ac->responded &&
+ ac->index != alist->preferred &&
+ test_bit(ac->alist->preferred, &ac->tried))
+ WRITE_ONCE(alist->preferred, ac->index);
+ afs_put_addrlist(alist);
+ ac->alist = NULL;
+ }
+
+ return ac->error;
+}