![David Howells](/assets/img/avatar_default.png)
AF_RXRPC tries to turn on IP_RECVERR and IP_MTU_DISCOVER on the UDP socket
it just opened for communications with the outside world, regardless of the
type of socket. Unfortunately, this doesn't work with an AF_INET6 socket.
Fix this by turning on IPV6_RECVERR and IPV6_MTU_DISCOVER instead if the
socket is of the AF_INET6 family.
Without this, kAFS server and address rotation doesn't work correctly
because the algorithm doesn't detect received network errors.
Fixes: 75b54cb57c
("rxrpc: Add IPv6 support")
Signed-off-by: David Howells <dhowells@redhat.com>
469 lines
11 KiB
C
469 lines
11 KiB
C
/* Local endpoint object management
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*
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* Copyright (C) 2016 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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/net.h>
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#include <linux/skbuff.h>
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#include <linux/slab.h>
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#include <linux/udp.h>
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#include <linux/ip.h>
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#include <linux/hashtable.h>
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#include <net/sock.h>
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#include <net/af_rxrpc.h>
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#include "ar-internal.h"
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static void rxrpc_local_processor(struct work_struct *);
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static void rxrpc_local_rcu(struct rcu_head *);
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/*
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* Compare a local to an address. Return -ve, 0 or +ve to indicate less than,
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* same or greater than.
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*
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* We explicitly don't compare the RxRPC service ID as we want to reject
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* conflicting uses by differing services. Further, we don't want to share
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* addresses with different options (IPv6), so we don't compare those bits
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* either.
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*/
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static long rxrpc_local_cmp_key(const struct rxrpc_local *local,
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const struct sockaddr_rxrpc *srx)
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{
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long diff;
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diff = ((local->srx.transport_type - srx->transport_type) ?:
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(local->srx.transport_len - srx->transport_len) ?:
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(local->srx.transport.family - srx->transport.family));
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if (diff != 0)
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return diff;
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switch (srx->transport.family) {
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case AF_INET:
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/* If the choice of UDP port is left up to the transport, then
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* the endpoint record doesn't match.
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*/
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return ((u16 __force)local->srx.transport.sin.sin_port -
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(u16 __force)srx->transport.sin.sin_port) ?:
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memcmp(&local->srx.transport.sin.sin_addr,
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&srx->transport.sin.sin_addr,
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sizeof(struct in_addr));
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#ifdef CONFIG_AF_RXRPC_IPV6
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case AF_INET6:
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/* If the choice of UDP6 port is left up to the transport, then
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* the endpoint record doesn't match.
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*/
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return ((u16 __force)local->srx.transport.sin6.sin6_port -
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(u16 __force)srx->transport.sin6.sin6_port) ?:
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memcmp(&local->srx.transport.sin6.sin6_addr,
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&srx->transport.sin6.sin6_addr,
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sizeof(struct in6_addr));
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#endif
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default:
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BUG();
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}
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}
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/*
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* Allocate a new local endpoint.
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*/
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static struct rxrpc_local *rxrpc_alloc_local(struct rxrpc_net *rxnet,
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const struct sockaddr_rxrpc *srx)
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{
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struct rxrpc_local *local;
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local = kzalloc(sizeof(struct rxrpc_local), GFP_KERNEL);
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if (local) {
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atomic_set(&local->usage, 1);
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local->rxnet = rxnet;
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INIT_LIST_HEAD(&local->link);
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INIT_WORK(&local->processor, rxrpc_local_processor);
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init_rwsem(&local->defrag_sem);
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skb_queue_head_init(&local->reject_queue);
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skb_queue_head_init(&local->event_queue);
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local->client_conns = RB_ROOT;
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spin_lock_init(&local->client_conns_lock);
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spin_lock_init(&local->lock);
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rwlock_init(&local->services_lock);
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local->debug_id = atomic_inc_return(&rxrpc_debug_id);
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memcpy(&local->srx, srx, sizeof(*srx));
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local->srx.srx_service = 0;
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trace_rxrpc_local(local, rxrpc_local_new, 1, NULL);
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}
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_leave(" = %p", local);
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return local;
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}
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/*
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* create the local socket
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* - must be called with rxrpc_local_mutex locked
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*/
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static int rxrpc_open_socket(struct rxrpc_local *local, struct net *net)
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{
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struct sock *sock;
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int ret, opt;
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_enter("%p{%d,%d}",
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local, local->srx.transport_type, local->srx.transport.family);
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/* create a socket to represent the local endpoint */
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ret = sock_create_kern(net, local->srx.transport.family,
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local->srx.transport_type, 0, &local->socket);
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if (ret < 0) {
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_leave(" = %d [socket]", ret);
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return ret;
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}
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/* if a local address was supplied then bind it */
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if (local->srx.transport_len > sizeof(sa_family_t)) {
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_debug("bind");
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ret = kernel_bind(local->socket,
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(struct sockaddr *)&local->srx.transport,
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local->srx.transport_len);
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if (ret < 0) {
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_debug("bind failed %d", ret);
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goto error;
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}
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}
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switch (local->srx.transport.family) {
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case AF_INET:
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/* we want to receive ICMP errors */
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opt = 1;
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ret = kernel_setsockopt(local->socket, SOL_IP, IP_RECVERR,
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(char *) &opt, sizeof(opt));
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if (ret < 0) {
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_debug("setsockopt failed");
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goto error;
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}
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/* we want to set the don't fragment bit */
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opt = IP_PMTUDISC_DO;
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ret = kernel_setsockopt(local->socket, SOL_IP, IP_MTU_DISCOVER,
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(char *) &opt, sizeof(opt));
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if (ret < 0) {
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_debug("setsockopt failed");
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goto error;
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}
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break;
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case AF_INET6:
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/* we want to receive ICMP errors */
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opt = 1;
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ret = kernel_setsockopt(local->socket, SOL_IPV6, IPV6_RECVERR,
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(char *) &opt, sizeof(opt));
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if (ret < 0) {
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_debug("setsockopt failed");
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goto error;
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}
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/* we want to set the don't fragment bit */
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opt = IPV6_PMTUDISC_DO;
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ret = kernel_setsockopt(local->socket, SOL_IPV6, IPV6_MTU_DISCOVER,
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(char *) &opt, sizeof(opt));
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if (ret < 0) {
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_debug("setsockopt failed");
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goto error;
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}
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break;
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default:
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BUG();
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}
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/* set the socket up */
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sock = local->socket->sk;
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sock->sk_user_data = local;
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sock->sk_data_ready = rxrpc_data_ready;
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sock->sk_error_report = rxrpc_error_report;
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_leave(" = 0");
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return 0;
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error:
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kernel_sock_shutdown(local->socket, SHUT_RDWR);
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local->socket->sk->sk_user_data = NULL;
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sock_release(local->socket);
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local->socket = NULL;
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_leave(" = %d", ret);
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return ret;
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}
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/*
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* Look up or create a new local endpoint using the specified local address.
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*/
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struct rxrpc_local *rxrpc_lookup_local(struct net *net,
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const struct sockaddr_rxrpc *srx)
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{
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struct rxrpc_local *local;
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struct rxrpc_net *rxnet = rxrpc_net(net);
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struct list_head *cursor;
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const char *age;
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long diff;
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int ret;
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_enter("{%d,%d,%pISp}",
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srx->transport_type, srx->transport.family, &srx->transport);
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mutex_lock(&rxnet->local_mutex);
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for (cursor = rxnet->local_endpoints.next;
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cursor != &rxnet->local_endpoints;
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cursor = cursor->next) {
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local = list_entry(cursor, struct rxrpc_local, link);
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diff = rxrpc_local_cmp_key(local, srx);
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if (diff < 0)
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continue;
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if (diff > 0)
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break;
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/* Services aren't allowed to share transport sockets, so
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* reject that here. It is possible that the object is dying -
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* but it may also still have the local transport address that
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* we want bound.
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*/
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if (srx->srx_service) {
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local = NULL;
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goto addr_in_use;
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}
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/* Found a match. We replace a dying object. Attempting to
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* bind the transport socket may still fail if we're attempting
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* to use a local address that the dying object is still using.
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*/
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if (!rxrpc_get_local_maybe(local)) {
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cursor = cursor->next;
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list_del_init(&local->link);
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break;
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}
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age = "old";
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goto found;
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}
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local = rxrpc_alloc_local(rxnet, srx);
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if (!local)
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goto nomem;
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ret = rxrpc_open_socket(local, net);
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if (ret < 0)
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goto sock_error;
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list_add_tail(&local->link, cursor);
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age = "new";
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found:
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mutex_unlock(&rxnet->local_mutex);
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_net("LOCAL %s %d {%pISp}",
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age, local->debug_id, &local->srx.transport);
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_leave(" = %p", local);
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return local;
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nomem:
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ret = -ENOMEM;
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sock_error:
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mutex_unlock(&rxnet->local_mutex);
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kfree(local);
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_leave(" = %d", ret);
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return ERR_PTR(ret);
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addr_in_use:
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mutex_unlock(&rxnet->local_mutex);
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_leave(" = -EADDRINUSE");
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return ERR_PTR(-EADDRINUSE);
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}
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/*
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* Get a ref on a local endpoint.
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*/
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struct rxrpc_local *rxrpc_get_local(struct rxrpc_local *local)
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{
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const void *here = __builtin_return_address(0);
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int n;
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n = atomic_inc_return(&local->usage);
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trace_rxrpc_local(local, rxrpc_local_got, n, here);
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return local;
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}
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/*
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* Get a ref on a local endpoint unless its usage has already reached 0.
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*/
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struct rxrpc_local *rxrpc_get_local_maybe(struct rxrpc_local *local)
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{
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const void *here = __builtin_return_address(0);
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if (local) {
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int n = __atomic_add_unless(&local->usage, 1, 0);
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if (n > 0)
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trace_rxrpc_local(local, rxrpc_local_got, n + 1, here);
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else
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local = NULL;
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}
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return local;
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}
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/*
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* Queue a local endpoint.
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*/
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void rxrpc_queue_local(struct rxrpc_local *local)
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{
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const void *here = __builtin_return_address(0);
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if (rxrpc_queue_work(&local->processor))
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trace_rxrpc_local(local, rxrpc_local_queued,
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atomic_read(&local->usage), here);
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}
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/*
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* A local endpoint reached its end of life.
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*/
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static void __rxrpc_put_local(struct rxrpc_local *local)
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{
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_enter("%d", local->debug_id);
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rxrpc_queue_work(&local->processor);
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}
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/*
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* Drop a ref on a local endpoint.
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*/
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void rxrpc_put_local(struct rxrpc_local *local)
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{
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const void *here = __builtin_return_address(0);
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int n;
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if (local) {
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n = atomic_dec_return(&local->usage);
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trace_rxrpc_local(local, rxrpc_local_put, n, here);
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if (n == 0)
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__rxrpc_put_local(local);
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}
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}
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/*
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* Destroy a local endpoint's socket and then hand the record to RCU to dispose
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* of.
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*
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* Closing the socket cannot be done from bottom half context or RCU callback
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* context because it might sleep.
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*/
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static void rxrpc_local_destroyer(struct rxrpc_local *local)
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{
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struct socket *socket = local->socket;
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struct rxrpc_net *rxnet = local->rxnet;
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_enter("%d", local->debug_id);
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/* We can get a race between an incoming call packet queueing the
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* processor again and the work processor starting the destruction
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* process which will shut down the UDP socket.
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*/
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if (local->dead) {
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_leave(" [already dead]");
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return;
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}
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local->dead = true;
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mutex_lock(&rxnet->local_mutex);
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list_del_init(&local->link);
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mutex_unlock(&rxnet->local_mutex);
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ASSERT(RB_EMPTY_ROOT(&local->client_conns));
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ASSERT(!local->service);
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if (socket) {
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local->socket = NULL;
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kernel_sock_shutdown(socket, SHUT_RDWR);
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socket->sk->sk_user_data = NULL;
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sock_release(socket);
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}
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/* At this point, there should be no more packets coming in to the
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* local endpoint.
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*/
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rxrpc_purge_queue(&local->reject_queue);
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rxrpc_purge_queue(&local->event_queue);
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_debug("rcu local %d", local->debug_id);
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call_rcu(&local->rcu, rxrpc_local_rcu);
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}
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/*
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* Process events on an endpoint
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*/
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static void rxrpc_local_processor(struct work_struct *work)
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{
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struct rxrpc_local *local =
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container_of(work, struct rxrpc_local, processor);
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bool again;
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trace_rxrpc_local(local, rxrpc_local_processing,
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atomic_read(&local->usage), NULL);
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do {
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again = false;
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if (atomic_read(&local->usage) == 0)
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return rxrpc_local_destroyer(local);
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if (!skb_queue_empty(&local->reject_queue)) {
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rxrpc_reject_packets(local);
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again = true;
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}
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if (!skb_queue_empty(&local->event_queue)) {
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rxrpc_process_local_events(local);
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again = true;
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}
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} while (again);
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}
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/*
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* Destroy a local endpoint after the RCU grace period expires.
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*/
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static void rxrpc_local_rcu(struct rcu_head *rcu)
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{
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struct rxrpc_local *local = container_of(rcu, struct rxrpc_local, rcu);
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_enter("%d", local->debug_id);
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ASSERT(!work_pending(&local->processor));
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_net("DESTROY LOCAL %d", local->debug_id);
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kfree(local);
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_leave("");
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}
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/*
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* Verify the local endpoint list is empty by this point.
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*/
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void rxrpc_destroy_all_locals(struct rxrpc_net *rxnet)
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{
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struct rxrpc_local *local;
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_enter("");
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flush_workqueue(rxrpc_workqueue);
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if (!list_empty(&rxnet->local_endpoints)) {
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mutex_lock(&rxnet->local_mutex);
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list_for_each_entry(local, &rxnet->local_endpoints, link) {
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pr_err("AF_RXRPC: Leaked local %p {%d}\n",
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local, atomic_read(&local->usage));
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}
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mutex_unlock(&rxnet->local_mutex);
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BUG();
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}
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}
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