| /* incoming call handling |
| * |
| * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. |
| * Written by David Howells (dhowells@redhat.com) |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version |
| * 2 of the License, or (at your option) any later version. |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include <linux/module.h> |
| #include <linux/net.h> |
| #include <linux/skbuff.h> |
| #include <linux/errqueue.h> |
| #include <linux/udp.h> |
| #include <linux/in.h> |
| #include <linux/in6.h> |
| #include <linux/icmp.h> |
| #include <linux/gfp.h> |
| #include <linux/circ_buf.h> |
| #include <net/sock.h> |
| #include <net/af_rxrpc.h> |
| #include <net/ip.h> |
| #include "ar-internal.h" |
| |
| /* |
| * Preallocate a single service call, connection and peer and, if possible, |
| * give them a user ID and attach the user's side of the ID to them. |
| */ |
| static int rxrpc_service_prealloc_one(struct rxrpc_sock *rx, |
| struct rxrpc_backlog *b, |
| rxrpc_notify_rx_t notify_rx, |
| rxrpc_user_attach_call_t user_attach_call, |
| unsigned long user_call_ID, gfp_t gfp) |
| { |
| const void *here = __builtin_return_address(0); |
| struct rxrpc_call *call; |
| int max, tmp; |
| unsigned int size = RXRPC_BACKLOG_MAX; |
| unsigned int head, tail, call_head, call_tail; |
| |
| max = rx->sk.sk_max_ack_backlog; |
| tmp = rx->sk.sk_ack_backlog; |
| if (tmp >= max) { |
| _leave(" = -ENOBUFS [full %u]", max); |
| return -ENOBUFS; |
| } |
| max -= tmp; |
| |
| /* We don't need more conns and peers than we have calls, but on the |
| * other hand, we shouldn't ever use more peers than conns or conns |
| * than calls. |
| */ |
| call_head = b->call_backlog_head; |
| call_tail = READ_ONCE(b->call_backlog_tail); |
| tmp = CIRC_CNT(call_head, call_tail, size); |
| if (tmp >= max) { |
| _leave(" = -ENOBUFS [enough %u]", tmp); |
| return -ENOBUFS; |
| } |
| max = tmp + 1; |
| |
| head = b->peer_backlog_head; |
| tail = READ_ONCE(b->peer_backlog_tail); |
| if (CIRC_CNT(head, tail, size) < max) { |
| struct rxrpc_peer *peer = rxrpc_alloc_peer(rx->local, gfp); |
| if (!peer) |
| return -ENOMEM; |
| b->peer_backlog[head] = peer; |
| smp_store_release(&b->peer_backlog_head, |
| (head + 1) & (size - 1)); |
| } |
| |
| head = b->conn_backlog_head; |
| tail = READ_ONCE(b->conn_backlog_tail); |
| if (CIRC_CNT(head, tail, size) < max) { |
| struct rxrpc_connection *conn; |
| |
| conn = rxrpc_prealloc_service_connection(gfp); |
| if (!conn) |
| return -ENOMEM; |
| b->conn_backlog[head] = conn; |
| smp_store_release(&b->conn_backlog_head, |
| (head + 1) & (size - 1)); |
| |
| trace_rxrpc_conn(conn, rxrpc_conn_new_service, |
| atomic_read(&conn->usage), here); |
| } |
| |
| /* Now it gets complicated, because calls get registered with the |
| * socket here, particularly if a user ID is preassigned by the user. |
| */ |
| call = rxrpc_alloc_call(gfp); |
| if (!call) |
| return -ENOMEM; |
| call->flags |= (1 << RXRPC_CALL_IS_SERVICE); |
| call->state = RXRPC_CALL_SERVER_PREALLOC; |
| |
| trace_rxrpc_call(call, rxrpc_call_new_service, |
| atomic_read(&call->usage), |
| here, (const void *)user_call_ID); |
| |
| write_lock(&rx->call_lock); |
| if (user_attach_call) { |
| struct rxrpc_call *xcall; |
| struct rb_node *parent, **pp; |
| |
| /* Check the user ID isn't already in use */ |
| pp = &rx->calls.rb_node; |
| parent = NULL; |
| while (*pp) { |
| parent = *pp; |
| xcall = rb_entry(parent, struct rxrpc_call, sock_node); |
| if (user_call_ID < call->user_call_ID) |
| pp = &(*pp)->rb_left; |
| else if (user_call_ID > call->user_call_ID) |
| pp = &(*pp)->rb_right; |
| else |
| goto id_in_use; |
| } |
| |
| call->user_call_ID = user_call_ID; |
| call->notify_rx = notify_rx; |
| rxrpc_get_call(call, rxrpc_call_got_kernel); |
| user_attach_call(call, user_call_ID); |
| rxrpc_get_call(call, rxrpc_call_got_userid); |
| rb_link_node(&call->sock_node, parent, pp); |
| rb_insert_color(&call->sock_node, &rx->calls); |
| set_bit(RXRPC_CALL_HAS_USERID, &call->flags); |
| } |
| |
| list_add(&call->sock_link, &rx->sock_calls); |
| |
| write_unlock(&rx->call_lock); |
| |
| write_lock(&rxrpc_call_lock); |
| list_add_tail(&call->link, &rxrpc_calls); |
| write_unlock(&rxrpc_call_lock); |
| |
| b->call_backlog[call_head] = call; |
| smp_store_release(&b->call_backlog_head, (call_head + 1) & (size - 1)); |
| _leave(" = 0 [%d -> %lx]", call->debug_id, user_call_ID); |
| return 0; |
| |
| id_in_use: |
| write_unlock(&rx->call_lock); |
| rxrpc_cleanup_call(call); |
| _leave(" = -EBADSLT"); |
| return -EBADSLT; |
| } |
| |
| /* |
| * Preallocate sufficient service connections, calls and peers to cover the |
| * entire backlog of a socket. When a new call comes in, if we don't have |
| * sufficient of each available, the call gets rejected as busy or ignored. |
| * |
| * The backlog is replenished when a connection is accepted or rejected. |
| */ |
| int rxrpc_service_prealloc(struct rxrpc_sock *rx, gfp_t gfp) |
| { |
| struct rxrpc_backlog *b = rx->backlog; |
| |
| if (!b) { |
| b = kzalloc(sizeof(struct rxrpc_backlog), gfp); |
| if (!b) |
| return -ENOMEM; |
| rx->backlog = b; |
| } |
| |
| if (rx->discard_new_call) |
| return 0; |
| |
| while (rxrpc_service_prealloc_one(rx, b, NULL, NULL, 0, gfp) == 0) |
| ; |
| |
| return 0; |
| } |
| |
| /* |
| * Discard the preallocation on a service. |
| */ |
| void rxrpc_discard_prealloc(struct rxrpc_sock *rx) |
| { |
| struct rxrpc_backlog *b = rx->backlog; |
| unsigned int size = RXRPC_BACKLOG_MAX, head, tail; |
| |
| if (!b) |
| return; |
| rx->backlog = NULL; |
| |
| /* Make sure that there aren't any incoming calls in progress before we |
| * clear the preallocation buffers. |
| */ |
| spin_lock_bh(&rx->incoming_lock); |
| spin_unlock_bh(&rx->incoming_lock); |
| |
| head = b->peer_backlog_head; |
| tail = b->peer_backlog_tail; |
| while (CIRC_CNT(head, tail, size) > 0) { |
| struct rxrpc_peer *peer = b->peer_backlog[tail]; |
| kfree(peer); |
| tail = (tail + 1) & (size - 1); |
| } |
| |
| head = b->conn_backlog_head; |
| tail = b->conn_backlog_tail; |
| while (CIRC_CNT(head, tail, size) > 0) { |
| struct rxrpc_connection *conn = b->conn_backlog[tail]; |
| write_lock(&rxrpc_connection_lock); |
| list_del(&conn->link); |
| list_del(&conn->proc_link); |
| write_unlock(&rxrpc_connection_lock); |
| kfree(conn); |
| tail = (tail + 1) & (size - 1); |
| } |
| |
| head = b->call_backlog_head; |
| tail = b->call_backlog_tail; |
| while (CIRC_CNT(head, tail, size) > 0) { |
| struct rxrpc_call *call = b->call_backlog[tail]; |
| if (rx->discard_new_call) { |
| _debug("discard %lx", call->user_call_ID); |
| rx->discard_new_call(call, call->user_call_ID); |
| rxrpc_put_call(call, rxrpc_call_put_kernel); |
| } |
| rxrpc_call_completed(call); |
| rxrpc_release_call(rx, call); |
| rxrpc_put_call(call, rxrpc_call_put); |
| tail = (tail + 1) & (size - 1); |
| } |
| |
| kfree(b); |
| } |
| |
| /* |
| * Allocate a new incoming call from the prealloc pool, along with a connection |
| * and a peer as necessary. |
| */ |
| static struct rxrpc_call *rxrpc_alloc_incoming_call(struct rxrpc_sock *rx, |
| struct rxrpc_local *local, |
| struct rxrpc_connection *conn, |
| struct sk_buff *skb) |
| { |
| struct rxrpc_backlog *b = rx->backlog; |
| struct rxrpc_peer *peer, *xpeer; |
| struct rxrpc_call *call; |
| unsigned short call_head, conn_head, peer_head; |
| unsigned short call_tail, conn_tail, peer_tail; |
| unsigned short call_count, conn_count; |
| |
| /* #calls >= #conns >= #peers must hold true. */ |
| call_head = smp_load_acquire(&b->call_backlog_head); |
| call_tail = b->call_backlog_tail; |
| call_count = CIRC_CNT(call_head, call_tail, RXRPC_BACKLOG_MAX); |
| conn_head = smp_load_acquire(&b->conn_backlog_head); |
| conn_tail = b->conn_backlog_tail; |
| conn_count = CIRC_CNT(conn_head, conn_tail, RXRPC_BACKLOG_MAX); |
| ASSERTCMP(conn_count, >=, call_count); |
| peer_head = smp_load_acquire(&b->peer_backlog_head); |
| peer_tail = b->peer_backlog_tail; |
| ASSERTCMP(CIRC_CNT(peer_head, peer_tail, RXRPC_BACKLOG_MAX), >=, |
| conn_count); |
| |
| if (call_count == 0) |
| return NULL; |
| |
| if (!conn) { |
| /* No connection. We're going to need a peer to start off |
| * with. If one doesn't yet exist, use a spare from the |
| * preallocation set. We dump the address into the spare in |
| * anticipation - and to save on stack space. |
| */ |
| xpeer = b->peer_backlog[peer_tail]; |
| if (rxrpc_extract_addr_from_skb(&xpeer->srx, skb) < 0) |
| return NULL; |
| |
| peer = rxrpc_lookup_incoming_peer(local, xpeer); |
| if (peer == xpeer) { |
| b->peer_backlog[peer_tail] = NULL; |
| smp_store_release(&b->peer_backlog_tail, |
| (peer_tail + 1) & |
| (RXRPC_BACKLOG_MAX - 1)); |
| } |
| |
| /* Now allocate and set up the connection */ |
| conn = b->conn_backlog[conn_tail]; |
| b->conn_backlog[conn_tail] = NULL; |
| smp_store_release(&b->conn_backlog_tail, |
| (conn_tail + 1) & (RXRPC_BACKLOG_MAX - 1)); |
| rxrpc_get_local(local); |
| conn->params.local = local; |
| conn->params.peer = peer; |
| rxrpc_see_connection(conn); |
| rxrpc_new_incoming_connection(conn, skb); |
| } else { |
| rxrpc_get_connection(conn); |
| } |
| |
| /* And now we can allocate and set up a new call */ |
| call = b->call_backlog[call_tail]; |
| b->call_backlog[call_tail] = NULL; |
| smp_store_release(&b->call_backlog_tail, |
| (call_tail + 1) & (RXRPC_BACKLOG_MAX - 1)); |
| |
| rxrpc_see_call(call); |
| call->conn = conn; |
| call->peer = rxrpc_get_peer(conn->params.peer); |
| return call; |
| } |
| |
| /* |
| * Set up a new incoming call. Called in BH context with the RCU read lock |
| * held. |
| * |
| * If this is for a kernel service, when we allocate the call, it will have |
| * three refs on it: (1) the kernel service, (2) the user_call_ID tree, (3) the |
| * retainer ref obtained from the backlog buffer. Prealloc calls for userspace |
| * services only have the ref from the backlog buffer. We want to pass this |
| * ref to non-BH context to dispose of. |
| * |
| * If we want to report an error, we mark the skb with the packet type and |
| * abort code and return NULL. |
| */ |
| struct rxrpc_call *rxrpc_new_incoming_call(struct rxrpc_local *local, |
| struct rxrpc_connection *conn, |
| struct sk_buff *skb) |
| { |
| struct rxrpc_skb_priv *sp = rxrpc_skb(skb); |
| struct rxrpc_sock *rx; |
| struct rxrpc_call *call; |
| u16 service_id = sp->hdr.serviceId; |
| |
| _enter(""); |
| |
| /* Get the socket providing the service */ |
| rx = rcu_dereference(local->service); |
| if (service_id == rx->srx.srx_service) |
| goto found_service; |
| |
| trace_rxrpc_abort("INV", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq, |
| RX_INVALID_OPERATION, EOPNOTSUPP); |
| skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT; |
| skb->priority = RX_INVALID_OPERATION; |
| _leave(" = NULL [service]"); |
| return NULL; |
| |
| found_service: |
| spin_lock(&rx->incoming_lock); |
| if (rx->sk.sk_state == RXRPC_CLOSE) { |
| trace_rxrpc_abort("CLS", sp->hdr.cid, sp->hdr.callNumber, |
| sp->hdr.seq, RX_INVALID_OPERATION, ESHUTDOWN); |
| skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT; |
| skb->priority = RX_INVALID_OPERATION; |
| _leave(" = NULL [close]"); |
| call = NULL; |
| goto out; |
| } |
| |
| call = rxrpc_alloc_incoming_call(rx, local, conn, skb); |
| if (!call) { |
| skb->mark = RXRPC_SKB_MARK_BUSY; |
| _leave(" = NULL [busy]"); |
| call = NULL; |
| goto out; |
| } |
| |
| trace_rxrpc_receive(call, rxrpc_receive_incoming, |
| sp->hdr.serial, sp->hdr.seq); |
| |
| /* Make the call live. */ |
| rxrpc_incoming_call(rx, call, skb); |
| conn = call->conn; |
| |
| if (rx->notify_new_call) |
| rx->notify_new_call(&rx->sk, call, call->user_call_ID); |
| else |
| sk_acceptq_added(&rx->sk); |
| |
| spin_lock(&conn->state_lock); |
| switch (conn->state) { |
| case RXRPC_CONN_SERVICE_UNSECURED: |
| conn->state = RXRPC_CONN_SERVICE_CHALLENGING; |
| set_bit(RXRPC_CONN_EV_CHALLENGE, &call->conn->events); |
| rxrpc_queue_conn(call->conn); |
| break; |
| |
| case RXRPC_CONN_SERVICE: |
| write_lock(&call->state_lock); |
| if (rx->discard_new_call) |
| call->state = RXRPC_CALL_SERVER_RECV_REQUEST; |
| else |
| call->state = RXRPC_CALL_SERVER_ACCEPTING; |
| write_unlock(&call->state_lock); |
| break; |
| |
| case RXRPC_CONN_REMOTELY_ABORTED: |
| rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED, |
| conn->remote_abort, ECONNABORTED); |
| break; |
| case RXRPC_CONN_LOCALLY_ABORTED: |
| rxrpc_abort_call("CON", call, sp->hdr.seq, |
| conn->local_abort, ECONNABORTED); |
| break; |
| default: |
| BUG(); |
| } |
| spin_unlock(&conn->state_lock); |
| |
| if (call->state == RXRPC_CALL_SERVER_ACCEPTING) |
| rxrpc_notify_socket(call); |
| |
| /* We have to discard the prealloc queue's ref here and rely on a |
| * combination of the RCU read lock and refs held either by the socket |
| * (recvmsg queue, to-be-accepted queue or user ID tree) or the kernel |
| * service to prevent the call from being deallocated too early. |
| */ |
| rxrpc_put_call(call, rxrpc_call_put); |
| |
| _leave(" = %p{%d}", call, call->debug_id); |
| out: |
| spin_unlock(&rx->incoming_lock); |
| return call; |
| } |
| |
| /* |
| * handle acceptance of a call by userspace |
| * - assign the user call ID to the call at the front of the queue |
| */ |
| struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx, |
| unsigned long user_call_ID, |
| rxrpc_notify_rx_t notify_rx) |
| { |
| struct rxrpc_call *call; |
| struct rb_node *parent, **pp; |
| int ret; |
| |
| _enter(",%lx", user_call_ID); |
| |
| ASSERT(!irqs_disabled()); |
| |
| write_lock(&rx->call_lock); |
| |
| if (list_empty(&rx->to_be_accepted)) { |
| write_unlock(&rx->call_lock); |
| kleave(" = -ENODATA [empty]"); |
| return ERR_PTR(-ENODATA); |
| } |
| |
| /* check the user ID isn't already in use */ |
| pp = &rx->calls.rb_node; |
| parent = NULL; |
| while (*pp) { |
| parent = *pp; |
| call = rb_entry(parent, struct rxrpc_call, sock_node); |
| |
| if (user_call_ID < call->user_call_ID) |
| pp = &(*pp)->rb_left; |
| else if (user_call_ID > call->user_call_ID) |
| pp = &(*pp)->rb_right; |
| else |
| goto id_in_use; |
| } |
| |
| /* Dequeue the first call and check it's still valid. We gain |
| * responsibility for the queue's reference. |
| */ |
| call = list_entry(rx->to_be_accepted.next, |
| struct rxrpc_call, accept_link); |
| list_del_init(&call->accept_link); |
| sk_acceptq_removed(&rx->sk); |
| rxrpc_see_call(call); |
| |
| write_lock_bh(&call->state_lock); |
| switch (call->state) { |
| case RXRPC_CALL_SERVER_ACCEPTING: |
| call->state = RXRPC_CALL_SERVER_RECV_REQUEST; |
| break; |
| case RXRPC_CALL_COMPLETE: |
| ret = call->error; |
| goto out_release; |
| default: |
| BUG(); |
| } |
| |
| /* formalise the acceptance */ |
| call->notify_rx = notify_rx; |
| call->user_call_ID = user_call_ID; |
| rxrpc_get_call(call, rxrpc_call_got_userid); |
| rb_link_node(&call->sock_node, parent, pp); |
| rb_insert_color(&call->sock_node, &rx->calls); |
| if (test_and_set_bit(RXRPC_CALL_HAS_USERID, &call->flags)) |
| BUG(); |
| |
| write_unlock_bh(&call->state_lock); |
| write_unlock(&rx->call_lock); |
| rxrpc_notify_socket(call); |
| rxrpc_service_prealloc(rx, GFP_KERNEL); |
| _leave(" = %p{%d}", call, call->debug_id); |
| return call; |
| |
| out_release: |
| _debug("release %p", call); |
| write_unlock_bh(&call->state_lock); |
| write_unlock(&rx->call_lock); |
| rxrpc_release_call(rx, call); |
| rxrpc_put_call(call, rxrpc_call_put); |
| goto out; |
| |
| id_in_use: |
| ret = -EBADSLT; |
| write_unlock(&rx->call_lock); |
| out: |
| rxrpc_service_prealloc(rx, GFP_KERNEL); |
| _leave(" = %d", ret); |
| return ERR_PTR(ret); |
| } |
| |
| /* |
| * Handle rejection of a call by userspace |
| * - reject the call at the front of the queue |
| */ |
| int rxrpc_reject_call(struct rxrpc_sock *rx) |
| { |
| struct rxrpc_call *call; |
| bool abort = false; |
| int ret; |
| |
| _enter(""); |
| |
| ASSERT(!irqs_disabled()); |
| |
| write_lock(&rx->call_lock); |
| |
| if (list_empty(&rx->to_be_accepted)) { |
| write_unlock(&rx->call_lock); |
| return -ENODATA; |
| } |
| |
| /* Dequeue the first call and check it's still valid. We gain |
| * responsibility for the queue's reference. |
| */ |
| call = list_entry(rx->to_be_accepted.next, |
| struct rxrpc_call, accept_link); |
| list_del_init(&call->accept_link); |
| sk_acceptq_removed(&rx->sk); |
| rxrpc_see_call(call); |
| |
| write_lock_bh(&call->state_lock); |
| switch (call->state) { |
| case RXRPC_CALL_SERVER_ACCEPTING: |
| __rxrpc_abort_call("REJ", call, 1, RX_USER_ABORT, ECONNABORTED); |
| abort = true; |
| /* fall through */ |
| case RXRPC_CALL_COMPLETE: |
| ret = call->error; |
| goto out_discard; |
| default: |
| BUG(); |
| } |
| |
| out_discard: |
| write_unlock_bh(&call->state_lock); |
| write_unlock(&rx->call_lock); |
| if (abort) { |
| rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ABORT); |
| rxrpc_release_call(rx, call); |
| rxrpc_put_call(call, rxrpc_call_put); |
| } |
| rxrpc_service_prealloc(rx, GFP_KERNEL); |
| _leave(" = %d", ret); |
| return ret; |
| } |
| |
| /* |
| * rxrpc_kernel_charge_accept - Charge up socket with preallocated calls |
| * @sock: The socket on which to preallocate |
| * @notify_rx: Event notification function for the call |
| * @user_attach_call: Func to attach call to user_call_ID |
| * @user_call_ID: The tag to attach to the preallocated call |
| * @gfp: The allocation conditions. |
| * |
| * Charge up the socket with preallocated calls, each with a user ID. A |
| * function should be provided to effect the attachment from the user's side. |
| * The user is given a ref to hold on the call. |
| * |
| * Note that the call may be come connected before this function returns. |
| */ |
| int rxrpc_kernel_charge_accept(struct socket *sock, |
| rxrpc_notify_rx_t notify_rx, |
| rxrpc_user_attach_call_t user_attach_call, |
| unsigned long user_call_ID, gfp_t gfp) |
| { |
| struct rxrpc_sock *rx = rxrpc_sk(sock->sk); |
| struct rxrpc_backlog *b = rx->backlog; |
| |
| if (sock->sk->sk_state == RXRPC_CLOSE) |
| return -ESHUTDOWN; |
| |
| return rxrpc_service_prealloc_one(rx, b, notify_rx, |
| user_attach_call, user_call_ID, |
| gfp); |
| } |
| EXPORT_SYMBOL(rxrpc_kernel_charge_accept); |