ar-input.c

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/* RxRPC packet reception
 *
 * 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 <net/udp.h>
#include <net/net_namespace.h>
#include "ar-internal.h"

unsigned long rxrpc_ack_timeout = 1;

const char *rxrpc_pkts[] = {
    "?00",
    "DATA", "ACK", "BUSY", "ABORT", "ACKALL", "CHALL", "RESP", "DEBUG",
    "?09", "?10", "?11", "?12", "?13", "?14", "?15"
};

/*
 * queue a packet for recvmsg to pass to userspace
 * - the caller must hold a lock on call->lock
 * - must not be called with interrupts disabled (sk_filter() disables BH's)
 * - eats the packet whether successful or not
 * - there must be just one reference to the packet, which the caller passes to
 *   this function
 */
int rxrpc_queue_rcv_skb(struct rxrpc_call *call, struct sk_buff *skb,
            bool force, bool terminal)
{
    struct rxrpc_skb_priv *sp;
    struct rxrpc_sock *rx = call->socket;
    struct sock *sk;
    int skb_len, ret;

    _enter(",,%d,%d", force, terminal);

    ASSERT(!irqs_disabled());

    sp = rxrpc_skb(skb);
    ASSERTCMP(sp->call, ==, call);

    /* if we've already posted the terminal message for a call, then we
     * don't post any more */
    if (test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags)) {
        _debug("already terminated");
        ASSERTCMP(call->state, >=, RXRPC_CALL_COMPLETE);
        skb->destructor = NULL;
        sp->call = NULL;
        rxrpc_put_call(call);
        rxrpc_free_skb(skb);
        return 0;
    }

    sk = &rx->sk;

    if (!force) {
        /* cast skb->rcvbuf to unsigned...  It's pointless, but
         * reduces number of warnings when compiling with -W
         * --ANK */
//      ret = -ENOBUFS;
//      if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
//          (unsigned int) sk->sk_rcvbuf)
//          goto out;

        ret = sk_filter(sk, skb);
        if (ret < 0)
            goto out;
    }

    spin_lock_bh(&sk->sk_receive_queue.lock);
    if (!test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags) &&
        !test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
        call->socket->sk.sk_state != RXRPC_CLOSE) {
        skb->destructor = rxrpc_packet_destructor;
        skb->dev = NULL;
        skb->sk = sk;
        atomic_add(skb->truesize, &sk->sk_rmem_alloc);

        if (terminal) {
            _debug("<<<< TERMINAL MESSAGE >>>>");
            set_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags);
        }

        /* allow interception by a kernel service */
        if (rx->interceptor) {
            rx->interceptor(sk, call->user_call_ID, skb);
            spin_unlock_bh(&sk->sk_receive_queue.lock);
        } else {

            /* Cache the SKB length before we tack it onto the
             * receive queue.  Once it is added it no longer
             * belongs to us and may be freed by other threads of
             * control pulling packets from the queue */
            skb_len = skb->len;

            _net("post skb %p", skb);
            __skb_queue_tail(&sk->sk_receive_queue, skb);
            spin_unlock_bh(&sk->sk_receive_queue.lock);

            if (!sock_flag(sk, SOCK_DEAD))
                sk->sk_data_ready(sk, skb_len);
        }
        skb = NULL;
    } else {
        spin_unlock_bh(&sk->sk_receive_queue.lock);
    }
    ret = 0;

out:
    /* release the socket buffer */
    if (skb) {
        skb->destructor = NULL;
        sp->call = NULL;
        rxrpc_put_call(call);
        rxrpc_free_skb(skb);
    }

    _leave(" = %d", ret);
    return ret;
}

/*
 * process a DATA packet, posting the packet to the appropriate queue
 * - eats the packet if successful
 */
static int rxrpc_fast_process_data(struct rxrpc_call *call,
                   struct sk_buff *skb, u32 seq)
{
    struct rxrpc_skb_priv *sp;
    bool terminal;
    int ret, ackbit, ack;

    _enter("{%u,%u},,{%u}", call->rx_data_post, call->rx_first_oos, seq);

    sp = rxrpc_skb(skb);
    ASSERTCMP(sp->call, ==, NULL);

    spin_lock(&call->lock);

    if (call->state > RXRPC_CALL_COMPLETE)
        goto discard;

    ASSERTCMP(call->rx_data_expect, >=, call->rx_data_post);
    ASSERTCMP(call->rx_data_post, >=, call->rx_data_recv);
    ASSERTCMP(call->rx_data_recv, >=, call->rx_data_eaten);

    if (seq < call->rx_data_post) {
        _debug("dup #%u [-%u]", seq, call->rx_data_post);
        ack = RXRPC_ACK_DUPLICATE;
        ret = -ENOBUFS;
        goto discard_and_ack;
    }

    /* we may already have the packet in the out of sequence queue */
    ackbit = seq - (call->rx_data_eaten + 1);
    ASSERTCMP(ackbit, >=, 0);
    if (__test_and_set_bit(ackbit, call->ackr_window)) {
        _debug("dup oos #%u [%u,%u]",
               seq, call->rx_data_eaten, call->rx_data_post);
        ack = RXRPC_ACK_DUPLICATE;
        goto discard_and_ack;
    }

    if (seq >= call->ackr_win_top) {
        _debug("exceed #%u [%u]", seq, call->ackr_win_top);
        __clear_bit(ackbit, call->ackr_window);
        ack = RXRPC_ACK_EXCEEDS_WINDOW;
        goto discard_and_ack;
    }

    if (seq == call->rx_data_expect) {
        clear_bit(RXRPC_CALL_EXPECT_OOS, &call->flags);
        call->rx_data_expect++;
    } else if (seq > call->rx_data_expect) {
        _debug("oos #%u [%u]", seq, call->rx_data_expect);
        call->rx_data_expect = seq + 1;
        if (test_and_set_bit(RXRPC_CALL_EXPECT_OOS, &call->flags)) {
            ack = RXRPC_ACK_OUT_OF_SEQUENCE;
            goto enqueue_and_ack;
        }
        goto enqueue_packet;
    }

    if (seq != call->rx_data_post) {
        _debug("ahead #%u [%u]", seq, call->rx_data_post);
        goto enqueue_packet;
    }

    if (test_bit(RXRPC_CALL_RCVD_LAST, &call->flags))
        goto protocol_error;

    /* if the packet need security things doing to it, then it goes down
     * the slow path */
    if (call->conn->security)
        goto enqueue_packet;

    sp->call = call;
    rxrpc_get_call(call);
    terminal = ((sp->hdr.flags & RXRPC_LAST_PACKET) &&
            !(sp->hdr.flags & RXRPC_CLIENT_INITIATED));
    ret = rxrpc_queue_rcv_skb(call, skb, false, terminal);
    if (ret < 0) {
        if (ret == -ENOMEM || ret == -ENOBUFS) {
            __clear_bit(ackbit, call->ackr_window);
            ack = RXRPC_ACK_NOSPACE;
            goto discard_and_ack;
        }
        goto out;
    }

    skb = NULL;

    _debug("post #%u", seq);
    ASSERTCMP(call->rx_data_post, ==, seq);
    call->rx_data_post++;

    if (sp->hdr.flags & RXRPC_LAST_PACKET)
        set_bit(RXRPC_CALL_RCVD_LAST, &call->flags);

    /* if we've reached an out of sequence packet then we need to drain
     * that queue into the socket Rx queue now */
    if (call->rx_data_post == call->rx_first_oos) {
        _debug("drain rx oos now");
        read_lock(&call->state_lock);
        if (call->state < RXRPC_CALL_COMPLETE &&
            !test_and_set_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events))
            rxrpc_queue_call(call);
        read_unlock(&call->state_lock);
    }

    spin_unlock(&call->lock);
    atomic_inc(&call->ackr_not_idle);
    rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, sp->hdr.serial, false);
    _leave(" = 0 [posted]");
    return 0;

protocol_error:
    ret = -EBADMSG;
out:
    spin_unlock(&call->lock);
    _leave(" = %d", ret);
    return ret;

discard_and_ack:
    _debug("discard and ACK packet %p", skb);
    __rxrpc_propose_ACK(call, ack, sp->hdr.serial, true);
discard:
    spin_unlock(&call->lock);
    rxrpc_free_skb(skb);
    _leave(" = 0 [discarded]");
    return 0;

enqueue_and_ack:
    __rxrpc_propose_ACK(call, ack, sp->hdr.serial, true);
enqueue_packet:
    _net("defer skb %p", skb);
    spin_unlock(&call->lock);
    skb_queue_tail(&call->rx_queue, skb);
    atomic_inc(&call->ackr_not_idle);
    read_lock(&call->state_lock);
    if (call->state < RXRPC_CALL_DEAD)
        rxrpc_queue_call(call);
    read_unlock(&call->state_lock);
    _leave(" = 0 [queued]");
    return 0;
}

/*
 * assume an implicit ACKALL of the transmission phase of a client socket upon
 * reception of the first reply packet
 */
static void rxrpc_assume_implicit_ackall(struct rxrpc_call *call, u32 serial)
{
    write_lock_bh(&call->state_lock);

    switch (call->state) {
    case RXRPC_CALL_CLIENT_AWAIT_REPLY:
        call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
        call->acks_latest = serial;

        _debug("implicit ACKALL %%%u", call->acks_latest);
        set_bit(RXRPC_CALL_RCVD_ACKALL, &call->events);
        write_unlock_bh(&call->state_lock);

        if (try_to_del_timer_sync(&call->resend_timer) >= 0) {
            clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
            clear_bit(RXRPC_CALL_RESEND, &call->events);
            clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
        }
        break;

    default:
        write_unlock_bh(&call->state_lock);
        break;
    }
}

/*
 * post an incoming packet to the nominated call to deal with
 * - must get rid of the sk_buff, either by freeing it or by queuing it
 */
void rxrpc_fast_process_packet(struct rxrpc_call *call, struct sk_buff *skb)
{
    struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
    __be32 _abort_code;
    u32 serial, hi_serial, seq, abort_code;

    _enter("%p,%p", call, skb);

    ASSERT(!irqs_disabled());

#if 0 // INJECT RX ERROR
    if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
        static int skip = 0;
        if (++skip == 3) {
            printk("DROPPED 3RD PACKET!!!!!!!!!!!!!\n");
            skip = 0;
            goto free_packet;
        }
    }
#endif

    /* track the latest serial number on this connection for ACK packet
     * information */
    serial = ntohl(sp->hdr.serial);
    hi_serial = atomic_read(&call->conn->hi_serial);
    while (serial > hi_serial)
        hi_serial = atomic_cmpxchg(&call->conn->hi_serial, hi_serial,
                       serial);

    /* request ACK generation for any ACK or DATA packet that requests
     * it */
    if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
        _proto("ACK Requested on %%%u", serial);
        rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED, sp->hdr.serial,
                  !(sp->hdr.flags & RXRPC_MORE_PACKETS));
    }

    switch (sp->hdr.type) {
    case RXRPC_PACKET_TYPE_ABORT:
        _debug("abort");

        if (skb_copy_bits(skb, 0, &_abort_code,
                  sizeof(_abort_code)) < 0)
            goto protocol_error;

        abort_code = ntohl(_abort_code);
        _proto("Rx ABORT %%%u { %x }", serial, abort_code);

        write_lock_bh(&call->state_lock);
        if (call->state < RXRPC_CALL_COMPLETE) {
            call->state = RXRPC_CALL_REMOTELY_ABORTED;
            call->abort_code = abort_code;
            set_bit(RXRPC_CALL_RCVD_ABORT, &call->events);
            rxrpc_queue_call(call);
        }
        goto free_packet_unlock;

    case RXRPC_PACKET_TYPE_BUSY:
        _proto("Rx BUSY %%%u", serial);

        if (call->conn->out_clientflag)
            goto protocol_error;

        write_lock_bh(&call->state_lock);
        switch (call->state) {
        case RXRPC_CALL_CLIENT_SEND_REQUEST:
            call->state = RXRPC_CALL_SERVER_BUSY;
            set_bit(RXRPC_CALL_RCVD_BUSY, &call->events);
            rxrpc_queue_call(call);
        case RXRPC_CALL_SERVER_BUSY:
            goto free_packet_unlock;
        default:
            goto protocol_error_locked;
        }

    default:
        _proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], serial);
        goto protocol_error;

    case RXRPC_PACKET_TYPE_DATA:
        seq = ntohl(sp->hdr.seq);

        _proto("Rx DATA %%%u { #%u }", serial, seq);

        if (seq == 0)
            goto protocol_error;

        call->ackr_prev_seq = sp->hdr.seq;

        /* received data implicitly ACKs all of the request packets we
         * sent when we're acting as a client */
        if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
            rxrpc_assume_implicit_ackall(call, serial);

        switch (rxrpc_fast_process_data(call, skb, seq)) {
        case 0:
            skb = NULL;
            goto done;

        default:
            BUG();

            /* data packet received beyond the last packet */
        case -EBADMSG:
            goto protocol_error;
        }

    case RXRPC_PACKET_TYPE_ACKALL:
    case RXRPC_PACKET_TYPE_ACK:
        /* ACK processing is done in process context */
        read_lock_bh(&call->state_lock);
        if (call->state < RXRPC_CALL_DEAD) {
            skb_queue_tail(&call->rx_queue, skb);
            rxrpc_queue_call(call);
            skb = NULL;
        }
        read_unlock_bh(&call->state_lock);
        goto free_packet;
    }

protocol_error:
    _debug("protocol error");
    write_lock_bh(&call->state_lock);
protocol_error_locked:
    if (call->state <= RXRPC_CALL_COMPLETE) {
        call->state = RXRPC_CALL_LOCALLY_ABORTED;
        call->abort_code = RX_PROTOCOL_ERROR;
        set_bit(RXRPC_CALL_ABORT, &call->events);
        rxrpc_queue_call(call);
    }
free_packet_unlock:
    write_unlock_bh(&call->state_lock);
free_packet:
    rxrpc_free_skb(skb);
done:
    _leave("");
}

/*
 * split up a jumbo data packet
 */
static void rxrpc_process_jumbo_packet(struct rxrpc_call *call,
                       struct sk_buff *jumbo)
{
    struct rxrpc_jumbo_header jhdr;
    struct rxrpc_skb_priv *sp;
    struct sk_buff *part;

    _enter(",{%u,%u}", jumbo->data_len, jumbo->len);

    sp = rxrpc_skb(jumbo);

    do {
        sp->hdr.flags &= ~RXRPC_JUMBO_PACKET;

        /* make a clone to represent the first subpacket in what's left
         * of the jumbo packet */
        part = skb_clone(jumbo, GFP_ATOMIC);
        if (!part) {
            /* simply ditch the tail in the event of ENOMEM */
            pskb_trim(jumbo, RXRPC_JUMBO_DATALEN);
            break;
        }
        rxrpc_new_skb(part);

        pskb_trim(part, RXRPC_JUMBO_DATALEN);

        if (!pskb_pull(jumbo, RXRPC_JUMBO_DATALEN))
            goto protocol_error;

        if (skb_copy_bits(jumbo, 0, &jhdr, sizeof(jhdr)) < 0)
            goto protocol_error;
        if (!pskb_pull(jumbo, sizeof(jhdr)))
            BUG();

        sp->hdr.seq = htonl(ntohl(sp->hdr.seq) + 1);
        sp->hdr.serial  = htonl(ntohl(sp->hdr.serial) + 1);
        sp->hdr.flags   = jhdr.flags;
        sp->hdr._rsvd   = jhdr._rsvd;

        _proto("Rx DATA Jumbo %%%u", ntohl(sp->hdr.serial) - 1);

        rxrpc_fast_process_packet(call, part);
        part = NULL;

    } while (sp->hdr.flags & RXRPC_JUMBO_PACKET);

    rxrpc_fast_process_packet(call, jumbo);
    _leave("");
    return;

protocol_error:
    _debug("protocol error");
    rxrpc_free_skb(part);
    rxrpc_free_skb(jumbo);
    write_lock_bh(&call->state_lock);
    if (call->state <= RXRPC_CALL_COMPLETE) {
        call->state = RXRPC_CALL_LOCALLY_ABORTED;
        call->abort_code = RX_PROTOCOL_ERROR;
        set_bit(RXRPC_CALL_ABORT, &call->events);
        rxrpc_queue_call(call);
    }
    write_unlock_bh(&call->state_lock);
    _leave("");
}

/*
 * post an incoming packet to the appropriate call/socket to deal with
 * - must get rid of the sk_buff, either by freeing it or by queuing it
 */
static void rxrpc_post_packet_to_call(struct rxrpc_connection *conn,
                      struct sk_buff *skb)
{
    struct rxrpc_skb_priv *sp;
    struct rxrpc_call *call;
    struct rb_node *p;
    __be32 call_id;

    _enter("%p,%p", conn, skb);

    read_lock_bh(&conn->lock);

    sp = rxrpc_skb(skb);

    /* look at extant calls by channel number first */
    call = conn->channels[ntohl(sp->hdr.cid) & RXRPC_CHANNELMASK];
    if (!call || call->call_id != sp->hdr.callNumber)
        goto call_not_extant;

    _debug("extant call [%d]", call->state);
    ASSERTCMP(call->conn, ==, conn);

    read_lock(&call->state_lock);
    switch (call->state) {
    case RXRPC_CALL_LOCALLY_ABORTED:
        if (!test_and_set_bit(RXRPC_CALL_ABORT, &call->events))
            rxrpc_queue_call(call);
    case RXRPC_CALL_REMOTELY_ABORTED:
    case RXRPC_CALL_NETWORK_ERROR:
    case RXRPC_CALL_DEAD:
        goto free_unlock;
    default:
        break;
    }

    read_unlock(&call->state_lock);
    rxrpc_get_call(call);
    read_unlock_bh(&conn->lock);

    if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
        sp->hdr.flags & RXRPC_JUMBO_PACKET)
        rxrpc_process_jumbo_packet(call, skb);
    else
        rxrpc_fast_process_packet(call, skb);

    rxrpc_put_call(call);
    goto done;

call_not_extant:
    /* search the completed calls in case what we're dealing with is
     * there */
    _debug("call not extant");

    call_id = sp->hdr.callNumber;
    p = conn->calls.rb_node;
    while (p) {
        call = rb_entry(p, struct rxrpc_call, conn_node);

        if (call_id < call->call_id)
            p = p->rb_left;
        else if (call_id > call->call_id)
            p = p->rb_right;
        else
            goto found_completed_call;
    }

dead_call:
    /* it's a either a really old call that we no longer remember or its a
     * new incoming call */
    read_unlock_bh(&conn->lock);

    if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
        sp->hdr.seq == cpu_to_be32(1)) {
        _debug("incoming call");
        skb_queue_tail(&conn->trans->local->accept_queue, skb);
        rxrpc_queue_work(&conn->trans->local->acceptor);
        goto done;
    }

    _debug("dead call");
    skb->priority = RX_CALL_DEAD;
    rxrpc_reject_packet(conn->trans->local, skb);
    goto done;

    /* resend last packet of a completed call
     * - client calls may have been aborted or ACK'd
     * - server calls may have been aborted
     */
found_completed_call:
    _debug("completed call");

    if (atomic_read(&call->usage) == 0)
        goto dead_call;

    /* synchronise any state changes */
    read_lock(&call->state_lock);
    ASSERTIFCMP(call->state != RXRPC_CALL_CLIENT_FINAL_ACK,
            call->state, >=, RXRPC_CALL_COMPLETE);

    if (call->state == RXRPC_CALL_LOCALLY_ABORTED ||
        call->state == RXRPC_CALL_REMOTELY_ABORTED ||
        call->state == RXRPC_CALL_DEAD) {
        read_unlock(&call->state_lock);
        goto dead_call;
    }

    if (call->conn->in_clientflag) {
        read_unlock(&call->state_lock);
        goto dead_call; /* complete server call */
    }

    _debug("final ack again");
    rxrpc_get_call(call);
    set_bit(RXRPC_CALL_ACK_FINAL, &call->events);
    rxrpc_queue_call(call);

free_unlock:
    read_unlock(&call->state_lock);
    read_unlock_bh(&conn->lock);
    rxrpc_free_skb(skb);
done:
    _leave("");
}

/*
 * post connection-level events to the connection
 * - this includes challenges, responses and some aborts
 */
static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
                      struct sk_buff *skb)
{
    _enter("%p,%p", conn, skb);

    atomic_inc(&conn->usage);
    skb_queue_tail(&conn->rx_queue, skb);
    rxrpc_queue_conn(conn);
}

/*
 * handle data received on the local endpoint
 * - may be called in interrupt context
 */
void rxrpc_data_ready(struct sock *sk, int count)
{
    struct rxrpc_connection *conn;
    struct rxrpc_transport *trans;
    struct rxrpc_skb_priv *sp;
    struct rxrpc_local *local;
    struct rxrpc_peer *peer;
    struct sk_buff *skb;
    int ret;

    _enter("%p, %d", sk, count);

    ASSERT(!irqs_disabled());

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

    skb = skb_recv_datagram(sk, 0, 1, &ret);
    if (!skb) {
        rxrpc_put_local(local);
        if (ret == -EAGAIN)
            return;
        _debug("UDP socket error %d", ret);
        return;
    }

    rxrpc_new_skb(skb);

    _net("recv skb %p", skb);

    /* we'll probably need to checksum it (didn't call sock_recvmsg) */
    if (skb_checksum_complete(skb)) {
        rxrpc_free_skb(skb);
        rxrpc_put_local(local);
        UDP_INC_STATS_BH(&init_net, UDP_MIB_INERRORS, 0);
        _leave(" [CSUM failed]");
        return;
    }

    UDP_INC_STATS_BH(&init_net, UDP_MIB_INDATAGRAMS, 0);

    /* the socket buffer we have is owned by UDP, with UDP's data all over
     * it, but we really want our own */
    skb_orphan(skb);
    sp = rxrpc_skb(skb);
    memset(sp, 0, sizeof(*sp));

    _net("Rx UDP packet from %08x:%04hu",
         ntohl(ip_hdr(skb)->saddr), ntohs(udp_hdr(skb)->source));

    /* dig out the RxRPC connection details */
    if (skb_copy_bits(skb, sizeof(struct udphdr), &sp->hdr,
              sizeof(sp->hdr)) < 0)
        goto bad_message;
    if (!pskb_pull(skb, sizeof(struct udphdr) + sizeof(sp->hdr)))
        BUG();

    _net("Rx RxRPC %s ep=%x call=%x:%x",
         sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
         ntohl(sp->hdr.epoch),
         ntohl(sp->hdr.cid),
         ntohl(sp->hdr.callNumber));

    if (sp->hdr.type == 0 || sp->hdr.type >= RXRPC_N_PACKET_TYPES) {
        _proto("Rx Bad Packet Type %u", sp->hdr.type);
        goto bad_message;
    }

    if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
        (sp->hdr.callNumber == 0 || sp->hdr.seq == 0))
        goto bad_message;

    peer = rxrpc_find_peer(local, ip_hdr(skb)->saddr, udp_hdr(skb)->source);
    if (IS_ERR(peer))
        goto cant_route_call;

    trans = rxrpc_find_transport(local, peer);
    rxrpc_put_peer(peer);
    if (!trans)
        goto cant_route_call;

    conn = rxrpc_find_connection(trans, &sp->hdr);
    rxrpc_put_transport(trans);
    if (!conn)
        goto cant_route_call;

    _debug("CONN %p {%d}", conn, conn->debug_id);

    if (sp->hdr.callNumber == 0)
        rxrpc_post_packet_to_conn(conn, skb);
    else
        rxrpc_post_packet_to_call(conn, skb);
    rxrpc_put_connection(conn);
    rxrpc_put_local(local);
    return;

cant_route_call:
    _debug("can't route call");
    if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
        sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
        if (sp->hdr.seq == cpu_to_be32(1)) {
            _debug("first packet");
            skb_queue_tail(&local->accept_queue, skb);
            rxrpc_queue_work(&local->acceptor);
            rxrpc_put_local(local);
            _leave(" [incoming]");
            return;
        }
        skb->priority = RX_INVALID_OPERATION;
    } else {
        skb->priority = RX_CALL_DEAD;
    }

    _debug("reject");
    rxrpc_reject_packet(local, skb);
    rxrpc_put_local(local);
    _leave(" [no call]");
    return;

bad_message:
    skb->priority = RX_PROTOCOL_ERROR;
    rxrpc_reject_packet(local, skb);
    rxrpc_put_local(local);
    _leave(" [badmsg]");
}