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491 lines
14 KiB
491 lines
14 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* incoming call handling |
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* |
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. |
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* Written by David Howells ([email protected]) |
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*/ |
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|
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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|
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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/errqueue.h> |
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#include <linux/udp.h> |
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#include <linux/in.h> |
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#include <linux/in6.h> |
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#include <linux/icmp.h> |
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#include <linux/gfp.h> |
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#include <linux/circ_buf.h> |
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#include <net/sock.h> |
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#include <net/af_rxrpc.h> |
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#include <net/ip.h> |
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#include "ar-internal.h" |
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static void rxrpc_dummy_notify(struct sock *sk, struct rxrpc_call *call, |
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unsigned long user_call_ID) |
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{ |
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} |
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|
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/* |
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* Preallocate a single service call, connection and peer and, if possible, |
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* give them a user ID and attach the user's side of the ID to them. |
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*/ |
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static int rxrpc_service_prealloc_one(struct rxrpc_sock *rx, |
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struct rxrpc_backlog *b, |
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rxrpc_notify_rx_t notify_rx, |
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rxrpc_user_attach_call_t user_attach_call, |
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unsigned long user_call_ID, gfp_t gfp, |
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unsigned int debug_id) |
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{ |
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const void *here = __builtin_return_address(0); |
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struct rxrpc_call *call, *xcall; |
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struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk)); |
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struct rb_node *parent, **pp; |
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int max, tmp; |
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unsigned int size = RXRPC_BACKLOG_MAX; |
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unsigned int head, tail, call_head, call_tail; |
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max = rx->sk.sk_max_ack_backlog; |
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tmp = rx->sk.sk_ack_backlog; |
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if (tmp >= max) { |
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_leave(" = -ENOBUFS [full %u]", max); |
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return -ENOBUFS; |
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} |
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max -= tmp; |
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/* We don't need more conns and peers than we have calls, but on the |
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* other hand, we shouldn't ever use more peers than conns or conns |
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* than calls. |
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*/ |
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call_head = b->call_backlog_head; |
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call_tail = READ_ONCE(b->call_backlog_tail); |
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tmp = CIRC_CNT(call_head, call_tail, size); |
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if (tmp >= max) { |
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_leave(" = -ENOBUFS [enough %u]", tmp); |
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return -ENOBUFS; |
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} |
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max = tmp + 1; |
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head = b->peer_backlog_head; |
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tail = READ_ONCE(b->peer_backlog_tail); |
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if (CIRC_CNT(head, tail, size) < max) { |
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struct rxrpc_peer *peer = rxrpc_alloc_peer(rx->local, gfp); |
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if (!peer) |
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return -ENOMEM; |
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b->peer_backlog[head] = peer; |
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smp_store_release(&b->peer_backlog_head, |
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(head + 1) & (size - 1)); |
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} |
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head = b->conn_backlog_head; |
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tail = READ_ONCE(b->conn_backlog_tail); |
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if (CIRC_CNT(head, tail, size) < max) { |
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struct rxrpc_connection *conn; |
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conn = rxrpc_prealloc_service_connection(rxnet, gfp); |
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if (!conn) |
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return -ENOMEM; |
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b->conn_backlog[head] = conn; |
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smp_store_release(&b->conn_backlog_head, |
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(head + 1) & (size - 1)); |
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trace_rxrpc_conn(conn->debug_id, rxrpc_conn_new_service, |
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atomic_read(&conn->usage), here); |
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} |
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/* Now it gets complicated, because calls get registered with the |
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* socket here, with a user ID preassigned by the user. |
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*/ |
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call = rxrpc_alloc_call(rx, gfp, debug_id); |
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if (!call) |
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return -ENOMEM; |
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call->flags |= (1 << RXRPC_CALL_IS_SERVICE); |
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call->state = RXRPC_CALL_SERVER_PREALLOC; |
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trace_rxrpc_call(call->debug_id, rxrpc_call_new_service, |
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atomic_read(&call->usage), |
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here, (const void *)user_call_ID); |
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write_lock(&rx->call_lock); |
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/* Check the user ID isn't already in use */ |
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pp = &rx->calls.rb_node; |
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parent = NULL; |
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while (*pp) { |
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parent = *pp; |
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xcall = rb_entry(parent, struct rxrpc_call, sock_node); |
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if (user_call_ID < xcall->user_call_ID) |
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pp = &(*pp)->rb_left; |
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else if (user_call_ID > xcall->user_call_ID) |
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pp = &(*pp)->rb_right; |
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else |
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goto id_in_use; |
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} |
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call->user_call_ID = user_call_ID; |
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call->notify_rx = notify_rx; |
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if (user_attach_call) { |
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rxrpc_get_call(call, rxrpc_call_got_kernel); |
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user_attach_call(call, user_call_ID); |
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} |
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rxrpc_get_call(call, rxrpc_call_got_userid); |
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rb_link_node(&call->sock_node, parent, pp); |
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rb_insert_color(&call->sock_node, &rx->calls); |
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set_bit(RXRPC_CALL_HAS_USERID, &call->flags); |
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list_add(&call->sock_link, &rx->sock_calls); |
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write_unlock(&rx->call_lock); |
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rxnet = call->rxnet; |
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write_lock(&rxnet->call_lock); |
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list_add_tail(&call->link, &rxnet->calls); |
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write_unlock(&rxnet->call_lock); |
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b->call_backlog[call_head] = call; |
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smp_store_release(&b->call_backlog_head, (call_head + 1) & (size - 1)); |
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_leave(" = 0 [%d -> %lx]", call->debug_id, user_call_ID); |
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return 0; |
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id_in_use: |
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write_unlock(&rx->call_lock); |
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rxrpc_cleanup_call(call); |
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_leave(" = -EBADSLT"); |
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return -EBADSLT; |
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} |
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/* |
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* Allocate the preallocation buffers for incoming service calls. These must |
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* be charged manually. |
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*/ |
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int rxrpc_service_prealloc(struct rxrpc_sock *rx, gfp_t gfp) |
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{ |
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struct rxrpc_backlog *b = rx->backlog; |
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if (!b) { |
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b = kzalloc(sizeof(struct rxrpc_backlog), gfp); |
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if (!b) |
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return -ENOMEM; |
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rx->backlog = b; |
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} |
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return 0; |
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} |
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/* |
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* Discard the preallocation on a service. |
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*/ |
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void rxrpc_discard_prealloc(struct rxrpc_sock *rx) |
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{ |
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struct rxrpc_backlog *b = rx->backlog; |
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struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk)); |
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unsigned int size = RXRPC_BACKLOG_MAX, head, tail; |
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if (!b) |
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return; |
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rx->backlog = NULL; |
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/* Make sure that there aren't any incoming calls in progress before we |
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* clear the preallocation buffers. |
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*/ |
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spin_lock_bh(&rx->incoming_lock); |
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spin_unlock_bh(&rx->incoming_lock); |
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head = b->peer_backlog_head; |
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tail = b->peer_backlog_tail; |
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while (CIRC_CNT(head, tail, size) > 0) { |
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struct rxrpc_peer *peer = b->peer_backlog[tail]; |
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rxrpc_put_local(peer->local); |
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kfree(peer); |
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tail = (tail + 1) & (size - 1); |
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} |
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head = b->conn_backlog_head; |
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tail = b->conn_backlog_tail; |
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while (CIRC_CNT(head, tail, size) > 0) { |
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struct rxrpc_connection *conn = b->conn_backlog[tail]; |
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write_lock(&rxnet->conn_lock); |
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list_del(&conn->link); |
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list_del(&conn->proc_link); |
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write_unlock(&rxnet->conn_lock); |
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kfree(conn); |
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if (atomic_dec_and_test(&rxnet->nr_conns)) |
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wake_up_var(&rxnet->nr_conns); |
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tail = (tail + 1) & (size - 1); |
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} |
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head = b->call_backlog_head; |
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tail = b->call_backlog_tail; |
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while (CIRC_CNT(head, tail, size) > 0) { |
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struct rxrpc_call *call = b->call_backlog[tail]; |
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rcu_assign_pointer(call->socket, rx); |
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if (rx->discard_new_call) { |
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_debug("discard %lx", call->user_call_ID); |
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rx->discard_new_call(call, call->user_call_ID); |
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if (call->notify_rx) |
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call->notify_rx = rxrpc_dummy_notify; |
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rxrpc_put_call(call, rxrpc_call_put_kernel); |
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} |
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rxrpc_call_completed(call); |
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rxrpc_release_call(rx, call); |
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rxrpc_put_call(call, rxrpc_call_put); |
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tail = (tail + 1) & (size - 1); |
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} |
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kfree(b); |
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} |
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/* |
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* Ping the other end to fill our RTT cache and to retrieve the rwind |
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* and MTU parameters. |
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*/ |
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static void rxrpc_send_ping(struct rxrpc_call *call, struct sk_buff *skb) |
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{ |
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struct rxrpc_skb_priv *sp = rxrpc_skb(skb); |
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ktime_t now = skb->tstamp; |
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if (call->peer->rtt_count < 3 || |
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ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000), now)) |
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rxrpc_propose_ACK(call, RXRPC_ACK_PING, sp->hdr.serial, |
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true, true, |
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rxrpc_propose_ack_ping_for_params); |
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} |
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/* |
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* Allocate a new incoming call from the prealloc pool, along with a connection |
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* and a peer as necessary. |
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*/ |
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static struct rxrpc_call *rxrpc_alloc_incoming_call(struct rxrpc_sock *rx, |
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struct rxrpc_local *local, |
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struct rxrpc_peer *peer, |
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struct rxrpc_connection *conn, |
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const struct rxrpc_security *sec, |
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struct sk_buff *skb) |
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{ |
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struct rxrpc_backlog *b = rx->backlog; |
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struct rxrpc_call *call; |
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unsigned short call_head, conn_head, peer_head; |
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unsigned short call_tail, conn_tail, peer_tail; |
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unsigned short call_count, conn_count; |
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/* #calls >= #conns >= #peers must hold true. */ |
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call_head = smp_load_acquire(&b->call_backlog_head); |
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call_tail = b->call_backlog_tail; |
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call_count = CIRC_CNT(call_head, call_tail, RXRPC_BACKLOG_MAX); |
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conn_head = smp_load_acquire(&b->conn_backlog_head); |
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conn_tail = b->conn_backlog_tail; |
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conn_count = CIRC_CNT(conn_head, conn_tail, RXRPC_BACKLOG_MAX); |
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ASSERTCMP(conn_count, >=, call_count); |
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peer_head = smp_load_acquire(&b->peer_backlog_head); |
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peer_tail = b->peer_backlog_tail; |
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ASSERTCMP(CIRC_CNT(peer_head, peer_tail, RXRPC_BACKLOG_MAX), >=, |
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conn_count); |
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if (call_count == 0) |
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return NULL; |
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if (!conn) { |
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if (peer && !rxrpc_get_peer_maybe(peer)) |
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peer = NULL; |
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if (!peer) { |
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peer = b->peer_backlog[peer_tail]; |
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if (rxrpc_extract_addr_from_skb(&peer->srx, skb) < 0) |
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return NULL; |
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b->peer_backlog[peer_tail] = NULL; |
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smp_store_release(&b->peer_backlog_tail, |
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(peer_tail + 1) & |
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(RXRPC_BACKLOG_MAX - 1)); |
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rxrpc_new_incoming_peer(rx, local, peer); |
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} |
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/* Now allocate and set up the connection */ |
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conn = b->conn_backlog[conn_tail]; |
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b->conn_backlog[conn_tail] = NULL; |
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smp_store_release(&b->conn_backlog_tail, |
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(conn_tail + 1) & (RXRPC_BACKLOG_MAX - 1)); |
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conn->params.local = rxrpc_get_local(local); |
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conn->params.peer = peer; |
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rxrpc_see_connection(conn); |
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rxrpc_new_incoming_connection(rx, conn, sec, skb); |
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} else { |
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rxrpc_get_connection(conn); |
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} |
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/* And now we can allocate and set up a new call */ |
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call = b->call_backlog[call_tail]; |
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b->call_backlog[call_tail] = NULL; |
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smp_store_release(&b->call_backlog_tail, |
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(call_tail + 1) & (RXRPC_BACKLOG_MAX - 1)); |
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rxrpc_see_call(call); |
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call->conn = conn; |
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call->security = conn->security; |
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call->security_ix = conn->security_ix; |
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call->peer = rxrpc_get_peer(conn->params.peer); |
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call->cong_cwnd = call->peer->cong_cwnd; |
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return call; |
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} |
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/* |
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* Set up a new incoming call. Called in BH context with the RCU read lock |
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* held. |
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* |
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* If this is for a kernel service, when we allocate the call, it will have |
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* three refs on it: (1) the kernel service, (2) the user_call_ID tree, (3) the |
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* retainer ref obtained from the backlog buffer. Prealloc calls for userspace |
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* services only have the ref from the backlog buffer. We want to pass this |
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* ref to non-BH context to dispose of. |
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* |
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* If we want to report an error, we mark the skb with the packet type and |
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* abort code and return NULL. |
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* |
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* The call is returned with the user access mutex held. |
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*/ |
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struct rxrpc_call *rxrpc_new_incoming_call(struct rxrpc_local *local, |
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struct rxrpc_sock *rx, |
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struct sk_buff *skb) |
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{ |
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struct rxrpc_skb_priv *sp = rxrpc_skb(skb); |
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const struct rxrpc_security *sec = NULL; |
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struct rxrpc_connection *conn; |
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struct rxrpc_peer *peer = NULL; |
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struct rxrpc_call *call = NULL; |
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_enter(""); |
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spin_lock(&rx->incoming_lock); |
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if (rx->sk.sk_state == RXRPC_SERVER_LISTEN_DISABLED || |
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rx->sk.sk_state == RXRPC_CLOSE) { |
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trace_rxrpc_abort(0, "CLS", sp->hdr.cid, sp->hdr.callNumber, |
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sp->hdr.seq, RX_INVALID_OPERATION, ESHUTDOWN); |
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skb->mark = RXRPC_SKB_MARK_REJECT_ABORT; |
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skb->priority = RX_INVALID_OPERATION; |
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goto no_call; |
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} |
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/* The peer, connection and call may all have sprung into existence due |
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* to a duplicate packet being handled on another CPU in parallel, so |
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* we have to recheck the routing. However, we're now holding |
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* rx->incoming_lock, so the values should remain stable. |
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*/ |
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conn = rxrpc_find_connection_rcu(local, skb, &peer); |
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if (!conn) { |
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sec = rxrpc_get_incoming_security(rx, skb); |
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if (!sec) |
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goto no_call; |
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} |
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call = rxrpc_alloc_incoming_call(rx, local, peer, conn, sec, skb); |
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if (!call) { |
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skb->mark = RXRPC_SKB_MARK_REJECT_BUSY; |
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goto no_call; |
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} |
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trace_rxrpc_receive(call, rxrpc_receive_incoming, |
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sp->hdr.serial, sp->hdr.seq); |
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/* Make the call live. */ |
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rxrpc_incoming_call(rx, call, skb); |
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conn = call->conn; |
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if (rx->notify_new_call) |
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rx->notify_new_call(&rx->sk, call, call->user_call_ID); |
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spin_lock(&conn->state_lock); |
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switch (conn->state) { |
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case RXRPC_CONN_SERVICE_UNSECURED: |
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conn->state = RXRPC_CONN_SERVICE_CHALLENGING; |
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set_bit(RXRPC_CONN_EV_CHALLENGE, &call->conn->events); |
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rxrpc_queue_conn(call->conn); |
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break; |
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case RXRPC_CONN_SERVICE: |
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write_lock(&call->state_lock); |
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if (call->state < RXRPC_CALL_COMPLETE) |
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call->state = RXRPC_CALL_SERVER_RECV_REQUEST; |
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write_unlock(&call->state_lock); |
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break; |
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case RXRPC_CONN_REMOTELY_ABORTED: |
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rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED, |
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conn->abort_code, conn->error); |
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break; |
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case RXRPC_CONN_LOCALLY_ABORTED: |
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rxrpc_abort_call("CON", call, sp->hdr.seq, |
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conn->abort_code, conn->error); |
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break; |
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default: |
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BUG(); |
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} |
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spin_unlock(&conn->state_lock); |
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spin_unlock(&rx->incoming_lock); |
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rxrpc_send_ping(call, skb); |
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|
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/* We have to discard the prealloc queue's ref here and rely on a |
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* combination of the RCU read lock and refs held either by the socket |
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* (recvmsg queue, to-be-accepted queue or user ID tree) or the kernel |
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* service to prevent the call from being deallocated too early. |
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*/ |
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rxrpc_put_call(call, rxrpc_call_put); |
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_leave(" = %p{%d}", call, call->debug_id); |
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return call; |
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no_call: |
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spin_unlock(&rx->incoming_lock); |
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_leave(" = NULL [%u]", skb->mark); |
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return NULL; |
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} |
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/* |
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* Charge up socket with preallocated calls, attaching user call IDs. |
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*/ |
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int rxrpc_user_charge_accept(struct rxrpc_sock *rx, unsigned long user_call_ID) |
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{ |
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struct rxrpc_backlog *b = rx->backlog; |
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if (rx->sk.sk_state == RXRPC_CLOSE) |
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return -ESHUTDOWN; |
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return rxrpc_service_prealloc_one(rx, b, NULL, NULL, user_call_ID, |
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GFP_KERNEL, |
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atomic_inc_return(&rxrpc_debug_id)); |
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} |
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/* |
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* rxrpc_kernel_charge_accept - Charge up socket with preallocated calls |
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* @sock: The socket on which to preallocate |
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* @notify_rx: Event notification function for the call |
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* @user_attach_call: Func to attach call to user_call_ID |
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* @user_call_ID: The tag to attach to the preallocated call |
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* @gfp: The allocation conditions. |
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* @debug_id: The tracing debug ID. |
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* |
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* Charge up the socket with preallocated calls, each with a user ID. A |
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* function should be provided to effect the attachment from the user's side. |
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* The user is given a ref to hold on the call. |
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* |
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* Note that the call may be come connected before this function returns. |
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*/ |
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int rxrpc_kernel_charge_accept(struct socket *sock, |
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rxrpc_notify_rx_t notify_rx, |
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rxrpc_user_attach_call_t user_attach_call, |
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unsigned long user_call_ID, gfp_t gfp, |
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unsigned int debug_id) |
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{ |
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struct rxrpc_sock *rx = rxrpc_sk(sock->sk); |
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struct rxrpc_backlog *b = rx->backlog; |
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|
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if (sock->sk->sk_state == RXRPC_CLOSE) |
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return -ESHUTDOWN; |
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return rxrpc_service_prealloc_one(rx, b, notify_rx, |
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user_attach_call, user_call_ID, |
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gfp, debug_id); |
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} |
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EXPORT_SYMBOL(rxrpc_kernel_charge_accept);
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