// 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; }