ar-accept.c

Go to the documentation of this file.

/* incoming call handling
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 *
 * 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.
 */

#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 <net/sock.h>
#include <net/af_rxrpc.h>
#include <net/ip.h>
#include "ar-internal.h"

/*
 * generate a connection-level abort
 */
static int rxrpc_busy(struct rxrpc_local *local, struct sockaddr_rxrpc *srx,
              struct rxrpc_header *hdr)
{
    struct msghdr msg;
    struct kvec iov[1];
    size_t len;
    int ret;

    _enter("%d,,", local->debug_id);

    msg.msg_name    = &srx->transport.sin;
    msg.msg_namelen = sizeof(srx->transport.sin);
    msg.msg_control = NULL;
    msg.msg_controllen = 0;
    msg.msg_flags   = 0;

    hdr->seq    = 0;
    hdr->type   = RXRPC_PACKET_TYPE_BUSY;
    hdr->flags  = 0;
    hdr->userStatus = 0;
    hdr->_rsvd  = 0;

    iov[0].iov_base = hdr;
    iov[0].iov_len  = sizeof(*hdr);

    len = iov[0].iov_len;

    hdr->serial = htonl(1);
    _proto("Tx BUSY %%%u", ntohl(hdr->serial));

    ret = kernel_sendmsg(local->socket, &msg, iov, 1, len);
    if (ret < 0) {
        _leave(" = -EAGAIN [sendmsg failed: %d]", ret);
        return -EAGAIN;
    }

    _leave(" = 0");
    return 0;
}

/*
 * accept an incoming call that needs peer, transport and/or connection setting
 * up
 */
static int rxrpc_accept_incoming_call(struct rxrpc_local *local,
                      struct rxrpc_sock *rx,
                      struct sk_buff *skb,
                      struct sockaddr_rxrpc *srx)
{
    struct rxrpc_connection *conn;
    struct rxrpc_transport *trans;
    struct rxrpc_skb_priv *sp, *nsp;
    struct rxrpc_peer *peer;
    struct rxrpc_call *call;
    struct sk_buff *notification;
    int ret;

    _enter("");

    sp = rxrpc_skb(skb);

    /* get a notification message to send to the server app */
    notification = alloc_skb(0, GFP_NOFS);
    if (!notification) {
        _debug("no memory");
        ret = -ENOMEM;
        goto error_nofree;
    }
    rxrpc_new_skb(notification);
    notification->mark = RXRPC_SKB_MARK_NEW_CALL;

    peer = rxrpc_get_peer(srx, GFP_NOIO);
    if (IS_ERR(peer)) {
        _debug("no peer");
        ret = -EBUSY;
        goto error;
    }

    trans = rxrpc_get_transport(local, peer, GFP_NOIO);
    rxrpc_put_peer(peer);
    if (IS_ERR(trans)) {
        _debug("no trans");
        ret = -EBUSY;
        goto error;
    }

    conn = rxrpc_incoming_connection(trans, &sp->hdr, GFP_NOIO);
    rxrpc_put_transport(trans);
    if (IS_ERR(conn)) {
        _debug("no conn");
        ret = PTR_ERR(conn);
        goto error;
    }

    call = rxrpc_incoming_call(rx, conn, &sp->hdr, GFP_NOIO);
    rxrpc_put_connection(conn);
    if (IS_ERR(call)) {
        _debug("no call");
        ret = PTR_ERR(call);
        goto error;
    }

    /* attach the call to the socket */
    read_lock_bh(&local->services_lock);
    if (rx->sk.sk_state == RXRPC_CLOSE)
        goto invalid_service;

    write_lock(&rx->call_lock);
    if (!test_and_set_bit(RXRPC_CALL_INIT_ACCEPT, &call->flags)) {
        rxrpc_get_call(call);

        spin_lock(&call->conn->state_lock);
        if (sp->hdr.securityIndex > 0 &&
            call->conn->state == RXRPC_CONN_SERVER_UNSECURED) {
            _debug("await conn sec");
            list_add_tail(&call->accept_link, &rx->secureq);
            call->conn->state = RXRPC_CONN_SERVER_CHALLENGING;
            atomic_inc(&call->conn->usage);
            set_bit(RXRPC_CONN_CHALLENGE, &call->conn->events);
            rxrpc_queue_conn(call->conn);
        } else {
            _debug("conn ready");
            call->state = RXRPC_CALL_SERVER_ACCEPTING;
            list_add_tail(&call->accept_link, &rx->acceptq);
            rxrpc_get_call(call);
            nsp = rxrpc_skb(notification);
            nsp->call = call;

            ASSERTCMP(atomic_read(&call->usage), >=, 3);

            _debug("notify");
            spin_lock(&call->lock);
            ret = rxrpc_queue_rcv_skb(call, notification, true,
                          false);
            spin_unlock(&call->lock);
            notification = NULL;
            BUG_ON(ret < 0);
        }
        spin_unlock(&call->conn->state_lock);

        _debug("queued");
    }
    write_unlock(&rx->call_lock);

    _debug("process");
    rxrpc_fast_process_packet(call, skb);

    _debug("done");
    read_unlock_bh(&local->services_lock);
    rxrpc_free_skb(notification);
    rxrpc_put_call(call);
    _leave(" = 0");
    return 0;

invalid_service:
    _debug("invalid");
    read_unlock_bh(&local->services_lock);

    read_lock_bh(&call->state_lock);
    if (!test_bit(RXRPC_CALL_RELEASE, &call->flags) &&
        !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events)) {
        rxrpc_get_call(call);
        rxrpc_queue_call(call);
    }
    read_unlock_bh(&call->state_lock);
    rxrpc_put_call(call);
    ret = -ECONNREFUSED;
error:
    rxrpc_free_skb(notification);
error_nofree:
    _leave(" = %d", ret);
    return ret;
}

/*
 * accept incoming calls that need peer, transport and/or connection setting up
 * - the packets we get are all incoming client DATA packets that have seq == 1
 */
void rxrpc_accept_incoming_calls(struct work_struct *work)
{
    struct rxrpc_local *local =
        container_of(work, struct rxrpc_local, acceptor);
    struct rxrpc_skb_priv *sp;
    struct sockaddr_rxrpc srx;
    struct rxrpc_sock *rx;
    struct sk_buff *skb;
    __be16 service_id;
    int ret;

    _enter("%d", local->debug_id);

    read_lock_bh(&rxrpc_local_lock);
    if (atomic_read(&local->usage) > 0)
        rxrpc_get_local(local);
    else
        local = NULL;
    read_unlock_bh(&rxrpc_local_lock);
    if (!local) {
        _leave(" [local dead]");
        return;
    }

process_next_packet:
    skb = skb_dequeue(&local->accept_queue);
    if (!skb) {
        rxrpc_put_local(local);
        _leave("\n");
        return;
    }

    _net("incoming call skb %p", skb);

    sp = rxrpc_skb(skb);

    /* determine the remote address */
    memset(&srx, 0, sizeof(srx));
    srx.srx_family = AF_RXRPC;
    srx.transport.family = local->srx.transport.family;
    srx.transport_type = local->srx.transport_type;
    switch (srx.transport.family) {
    case AF_INET:
        srx.transport_len = sizeof(struct sockaddr_in);
        srx.transport.sin.sin_port = udp_hdr(skb)->source;
        srx.transport.sin.sin_addr.s_addr = ip_hdr(skb)->saddr;
        break;
    default:
        goto busy;
    }

    /* get the socket providing the service */
    service_id = sp->hdr.serviceId;
    read_lock_bh(&local->services_lock);
    list_for_each_entry(rx, &local->services, listen_link) {
        if (rx->service_id == service_id &&
            rx->sk.sk_state != RXRPC_CLOSE)
            goto found_service;
    }
    read_unlock_bh(&local->services_lock);
    goto invalid_service;

found_service:
    _debug("found service %hd", ntohs(rx->service_id));
    if (sk_acceptq_is_full(&rx->sk))
        goto backlog_full;
    sk_acceptq_added(&rx->sk);
    sock_hold(&rx->sk);
    read_unlock_bh(&local->services_lock);

    ret = rxrpc_accept_incoming_call(local, rx, skb, &srx);
    if (ret < 0)
        sk_acceptq_removed(&rx->sk);
    sock_put(&rx->sk);
    switch (ret) {
    case -ECONNRESET: /* old calls are ignored */
    case -ECONNABORTED: /* aborted calls are reaborted or ignored */
    case 0:
        goto process_next_packet;
    case -ECONNREFUSED:
        goto invalid_service;
    case -EBUSY:
        goto busy;
    case -EKEYREJECTED:
        goto security_mismatch;
    default:
        BUG();
    }

backlog_full:
    read_unlock_bh(&local->services_lock);
busy:
    rxrpc_busy(local, &srx, &sp->hdr);
    rxrpc_free_skb(skb);
    goto process_next_packet;

invalid_service:
    skb->priority = RX_INVALID_OPERATION;
    rxrpc_reject_packet(local, skb);
    goto process_next_packet;

    /* can't change connection security type mid-flow */
security_mismatch:
    skb->priority = RX_PROTOCOL_ERROR;
    rxrpc_reject_packet(local, skb);
    goto process_next_packet;
}

/*
 * 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)
{
    struct rxrpc_call *call;
    struct rb_node *parent, **pp;
    int ret;

    _enter(",%lx", user_call_ID);

    ASSERT(!irqs_disabled());

    write_lock(&rx->call_lock);

    ret = -ENODATA;
    if (list_empty(&rx->acceptq))
        goto out;

    /* check the user ID isn't already in use */
    ret = -EBADSLT;
    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 out;
    }

    /* dequeue the first call and check it's still valid */
    call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
    list_del_init(&call->accept_link);
    sk_acceptq_removed(&rx->sk);

    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_REMOTELY_ABORTED:
    case RXRPC_CALL_LOCALLY_ABORTED:
        ret = -ECONNABORTED;
        goto out_release;
    case RXRPC_CALL_NETWORK_ERROR:
        ret = call->conn->error;
        goto out_release;
    case RXRPC_CALL_DEAD:
        ret = -ETIME;
        goto out_discard;
    default:
        BUG();
    }

    /* formalise the acceptance */
    call->user_call_ID = user_call_ID;
    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();
    if (test_and_set_bit(RXRPC_CALL_ACCEPTED, &call->events))
        BUG();
    rxrpc_queue_call(call);

    rxrpc_get_call(call);
    write_unlock_bh(&call->state_lock);
    write_unlock(&rx->call_lock);
    _leave(" = %p{%d}", call, call->debug_id);
    return call;

    /* if the call is already dying or dead, then we leave the socket's ref
     * on it to be released by rxrpc_dead_call_expired() as induced by
     * rxrpc_release_call() */
out_release:
    _debug("release %p", call);
    if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
        !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
        rxrpc_queue_call(call);
out_discard:
    write_unlock_bh(&call->state_lock);
    _debug("discard %p", call);
out:
    write_unlock(&rx->call_lock);
    _leave(" = %d", ret);
    return ERR_PTR(ret);
}

/*
 * handle rejectance 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;
    int ret;

    _enter("");

    ASSERT(!irqs_disabled());

    write_lock(&rx->call_lock);

    ret = -ENODATA;
    if (list_empty(&rx->acceptq))
        goto out;

    /* dequeue the first call and check it's still valid */
    call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
    list_del_init(&call->accept_link);
    sk_acceptq_removed(&rx->sk);

    write_lock_bh(&call->state_lock);
    switch (call->state) {
    case RXRPC_CALL_SERVER_ACCEPTING:
        call->state = RXRPC_CALL_SERVER_BUSY;
        if (test_and_set_bit(RXRPC_CALL_REJECT_BUSY, &call->events))
            rxrpc_queue_call(call);
        ret = 0;
        goto out_release;
    case RXRPC_CALL_REMOTELY_ABORTED:
    case RXRPC_CALL_LOCALLY_ABORTED:
        ret = -ECONNABORTED;
        goto out_release;
    case RXRPC_CALL_NETWORK_ERROR:
        ret = call->conn->error;
        goto out_release;
    case RXRPC_CALL_DEAD:
        ret = -ETIME;
        goto out_discard;
    default:
        BUG();
    }

    /* if the call is already dying or dead, then we leave the socket's ref
     * on it to be released by rxrpc_dead_call_expired() as induced by
     * rxrpc_release_call() */
out_release:
    _debug("release %p", call);
    if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
        !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
        rxrpc_queue_call(call);
out_discard:
    write_unlock_bh(&call->state_lock);
    _debug("discard %p", call);
out:
    write_unlock(&rx->call_lock);
    _leave(" = %d", ret);
    return ret;
}

struct rxrpc_call *rxrpc_kernel_accept_call(struct socket *sock,
                        unsigned long user_call_ID)
{
    struct rxrpc_call *call;

    _enter(",%lx", user_call_ID);
    call = rxrpc_accept_call(rxrpc_sk(sock->sk), user_call_ID);
    _leave(" = %p", call);
    return call;
}

EXPORT_SYMBOL(rxrpc_kernel_accept_call);

int rxrpc_kernel_reject_call(struct socket *sock)
{
    int ret;

    _enter("");
    ret = rxrpc_reject_call(rxrpc_sk(sock->sk));
    _leave(" = %d", ret);
    return ret;
}

EXPORT_SYMBOL(rxrpc_kernel_reject_call);