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root/net/rxrpc/ar-error.c

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DEFINITIONS

This source file includes following definitions.
  1. rxrpc_UDP_error_report
  2. rxrpc_UDP_error_handler

/* Error message handling (ICMP)
 *
 * 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.
 */

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

/*
 * handle an error received on the local endpoint
 */
void rxrpc_UDP_error_report(struct sock *sk)
{
        struct sock_exterr_skb *serr;
        struct rxrpc_transport *trans;
        struct rxrpc_local *local = sk->sk_user_data;
        struct rxrpc_peer *peer;
        struct sk_buff *skb;
        __be32 addr;
        __be16 port;

        _enter("%p{%d}", sk, local->debug_id);

        skb = skb_dequeue(&sk->sk_error_queue);
        if (!skb) {
                _leave("UDP socket errqueue empty");
                return;
        }

        rxrpc_new_skb(skb);

        serr = SKB_EXT_ERR(skb);
        addr = *(__be32 *)(skb_network_header(skb) + serr->addr_offset);
        port = serr->port;

        _net("Rx UDP Error from "NIPQUAD_FMT":%hu",
             NIPQUAD(addr), ntohs(port));
        _debug("Msg l:%d d:%d", skb->len, skb->data_len);

        peer = rxrpc_find_peer(local, addr, port);
        if (IS_ERR(peer)) {
                rxrpc_free_skb(skb);
                _leave(" [no peer]");
                return;
        }

        trans = rxrpc_find_transport(local, peer);
        if (!trans) {
                rxrpc_put_peer(peer);
                rxrpc_free_skb(skb);
                _leave(" [no trans]");
                return;
        }

        if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
            serr->ee.ee_type == ICMP_DEST_UNREACH &&
            serr->ee.ee_code == ICMP_FRAG_NEEDED
            ) {
                u32 mtu = serr->ee.ee_info;

                _net("Rx Received ICMP Fragmentation Needed (%d)", mtu);

                /* wind down the local interface MTU */
                if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {
                        peer->if_mtu = mtu;
                        _net("I/F MTU %u", mtu);
                }

                /* ip_rt_frag_needed() may have eaten the info */
                if (mtu == 0)
                        mtu = ntohs(icmp_hdr(skb)->un.frag.mtu);

                if (mtu == 0) {
                        /* they didn't give us a size, estimate one */
                        if (mtu > 1500) {
                                mtu >>= 1;
                                if (mtu < 1500)
                                        mtu = 1500;
                        } else {
                                mtu -= 100;
                                if (mtu < peer->hdrsize)
                                        mtu = peer->hdrsize + 4;
                        }
                }

                if (mtu < peer->mtu) {
                        spin_lock_bh(&peer->lock);
                        peer->mtu = mtu;
                        peer->maxdata = peer->mtu - peer->hdrsize;
                        spin_unlock_bh(&peer->lock);
                        _net("Net MTU %u (maxdata %u)",
                             peer->mtu, peer->maxdata);
                }
        }

        rxrpc_put_peer(peer);

        /* pass the transport ref to error_handler to release */
        skb_queue_tail(&trans->error_queue, skb);
        rxrpc_queue_work(&trans->error_handler);

        /* reset and regenerate socket error */
        spin_lock_bh(&sk->sk_error_queue.lock);
        sk->sk_err = 0;
        skb = skb_peek(&sk->sk_error_queue);
        if (skb) {
                sk->sk_err = SKB_EXT_ERR(skb)->ee.ee_errno;
                spin_unlock_bh(&sk->sk_error_queue.lock);
                sk->sk_error_report(sk);
        } else {
                spin_unlock_bh(&sk->sk_error_queue.lock);
        }

        _leave("");
}

/*
 * deal with UDP error messages
 */
void rxrpc_UDP_error_handler(struct work_struct *work)
{
        struct sock_extended_err *ee;
        struct sock_exterr_skb *serr;
        struct rxrpc_transport *trans =
                container_of(work, struct rxrpc_transport, error_handler);
        struct sk_buff *skb;
        int local, err;

        _enter("");

        skb = skb_dequeue(&trans->error_queue);
        if (!skb)
                return;

        serr = SKB_EXT_ERR(skb);
        ee = &serr->ee;

        _net("Rx Error o=%d t=%d c=%d e=%d",
             ee->ee_origin, ee->ee_type, ee->ee_code, ee->ee_errno);

        err = ee->ee_errno;

        switch (ee->ee_origin) {
        case SO_EE_ORIGIN_ICMP:
                local = 0;
                switch (ee->ee_type) {
                case ICMP_DEST_UNREACH:
                        switch (ee->ee_code) {
                        case ICMP_NET_UNREACH:
                                _net("Rx Received ICMP Network Unreachable");
                                err = ENETUNREACH;
                                break;
                        case ICMP_HOST_UNREACH:
                                _net("Rx Received ICMP Host Unreachable");
                                err = EHOSTUNREACH;
                                break;
                        case ICMP_PORT_UNREACH:
                                _net("Rx Received ICMP Port Unreachable");
                                err = ECONNREFUSED;
                                break;
                        case ICMP_FRAG_NEEDED:
                                _net("Rx Received ICMP Fragmentation Needed (%d)",
                                     ee->ee_info);
                                err = 0; /* dealt with elsewhere */
                                break;
                        case ICMP_NET_UNKNOWN:
                                _net("Rx Received ICMP Unknown Network");
                                err = ENETUNREACH;
                                break;
                        case ICMP_HOST_UNKNOWN:
                                _net("Rx Received ICMP Unknown Host");
                                err = EHOSTUNREACH;
                                break;
                        default:
                                _net("Rx Received ICMP DestUnreach code=%u",
                                     ee->ee_code);
                                break;
                        }
                        break;

                case ICMP_TIME_EXCEEDED:
                        _net("Rx Received ICMP TTL Exceeded");
                        break;

                default:
                        _proto("Rx Received ICMP error { type=%u code=%u }",
                               ee->ee_type, ee->ee_code);
                        break;
                }
                break;

        case SO_EE_ORIGIN_LOCAL:
                _proto("Rx Received local error { error=%d }",
                       ee->ee_errno);
                local = 1;
                break;

        case SO_EE_ORIGIN_NONE:
        case SO_EE_ORIGIN_ICMP6:
        default:
                _proto("Rx Received error report { orig=%u }",
                       ee->ee_origin);
                local = 0;
                break;
        }

        /* terminate all the affected calls if there's an unrecoverable
         * error */
        if (err) {
                struct rxrpc_call *call, *_n;

                _debug("ISSUE ERROR %d", err);

                spin_lock_bh(&trans->peer->lock);
                trans->peer->net_error = err;

                list_for_each_entry_safe(call, _n, &trans->peer->error_targets,
                                         error_link) {
                        write_lock(&call->state_lock);
                        if (call->state != RXRPC_CALL_COMPLETE &&
                            call->state < RXRPC_CALL_NETWORK_ERROR) {
                                call->state = RXRPC_CALL_NETWORK_ERROR;
                                set_bit(RXRPC_CALL_RCVD_ERROR, &call->events);
                                rxrpc_queue_call(call);
                        }
                        write_unlock(&call->state_lock);
                        list_del_init(&call->error_link);
                }

                spin_unlock_bh(&trans->peer->lock);
        }

        if (!skb_queue_empty(&trans->error_queue))
                rxrpc_queue_work(&trans->error_handler);

        rxrpc_free_skb(skb);
        rxrpc_put_transport(trans);
        _leave("");
}

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