ipcp.c

Go to the documentation of this file.

/*
 * Copyright (c) 2008 Jiri Svoboda
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdio.h>
#include <stdlib.h>
#include <adt/hash_table.h>
#include <sys/typefmt.h>

#include "ipc_desc.h"
#include "proto.h"
#include "trace.h"
#include "ipcp.h"

#define IPCP_CALLID_SYNC 0

typedef struct {
        sysarg_t phone_hash;
        ipc_call_t question;
        oper_t *oper;

        ipc_callid_t call_hash;

        link_t link;
} pending_call_t;

typedef struct {
        int server;
        proto_t *proto;
} connection_t;

#define MAX_PHONE 64
connection_t connections[MAX_PHONE];
int have_conn[MAX_PHONE];

#define PCALL_TABLE_CHAINS 32
hash_table_t pending_calls;

/*
 * Pseudo-protocols
 */
proto_t *proto_system;          
proto_t *proto_unknown;         
static hash_index_t pending_call_hash(unsigned long key[]);
static int pending_call_compare(unsigned long key[], hash_count_t keys,
    link_t *item);
static void pending_call_remove_callback(link_t *item);

hash_table_operations_t pending_call_ops = {
        .hash = pending_call_hash,
        .compare = pending_call_compare,
        .remove_callback = pending_call_remove_callback
};


static hash_index_t pending_call_hash(unsigned long key[])
{
//      printf("pending_call_hash\n");
        return key[0] % PCALL_TABLE_CHAINS;
}

static int pending_call_compare(unsigned long key[], hash_count_t keys,
    link_t *item)
{
        pending_call_t *hs;

//      printf("pending_call_compare\n");
        hs = hash_table_get_instance(item, pending_call_t, link);

        // FIXME: this will fail if sizeof(long) < sizeof(void *).
        return key[0] == hs->call_hash;
}

static void pending_call_remove_callback(link_t *item)
{
//      printf("pending_call_remove_callback\n");
}


void ipcp_connection_set(int phone, int server, proto_t *proto)
{
        if (phone <0 || phone >= MAX_PHONE) return;
        connections[phone].server = server;
        connections[phone].proto = proto;
        have_conn[phone] = 1;
}

void ipcp_connection_clear(int phone)
{
        have_conn[phone] = 0;
        connections[phone].server = 0;
        connections[phone].proto = NULL;
}

static void ipc_m_print(proto_t *proto, sysarg_t method)
{
        oper_t *oper;

        /* Try system methods first */
        oper = proto_get_oper(proto_system, method);

        if (oper == NULL && proto != NULL) {
                /* Not a system method, try the user protocol. */
                oper = proto_get_oper(proto, method);
        }

        if (oper != NULL) {
                printf("%s (%" PRIun ")", oper->name, method);
                return;
        }

        printf("%" PRIun, method);
}

void ipcp_init(void)
{
        ipc_m_desc_t *desc;
        oper_t *oper;

        val_type_t arg_def[OPER_MAX_ARGS] = {
                V_INTEGER,
                V_INTEGER,
                V_INTEGER,
                V_INTEGER,
                V_INTEGER               
        };

        /*
         * Create a pseudo-protocol 'unknown' that has no known methods.
         */
        proto_unknown = proto_new("unknown");

        /*
         * Create a pseudo-protocol 'system' defining names of system IPC
         * methods.
         */
        proto_system = proto_new("system");

        desc = ipc_methods;
        while (desc->number != 0) {
                oper = oper_new(desc->name, OPER_MAX_ARGS, arg_def, V_INTEGER,
                        OPER_MAX_ARGS, arg_def);
                proto_add_oper(proto_system, desc->number, oper);

                ++desc;
        }

        hash_table_create(&pending_calls, PCALL_TABLE_CHAINS, 1, &pending_call_ops);
}

void ipcp_cleanup(void)
{
        proto_delete(proto_system);
        hash_table_destroy(&pending_calls);
}

void ipcp_call_out(int phone, ipc_call_t *call, ipc_callid_t hash)
{
        pending_call_t *pcall;
        proto_t *proto;
        unsigned long key[1];
        oper_t *oper;
        sysarg_t *args;
        int i;

        if (have_conn[phone]) proto = connections[phone].proto;
        else proto = NULL;

        args = call->args;

        if ((display_mask & DM_IPC) != 0) {
                printf("Call ID: %p, phone: %d, proto: %s, method: ",
                    (void *) hash, phone,
                    (proto ? proto->name : "n/a"));
                ipc_m_print(proto, IPC_GET_IMETHOD(*call));
                printf(" args: (%" PRIun ", %" PRIun ", %" PRIun ", "
                    "%" PRIun ", %" PRIun ")\n",
                    args[1], args[2], args[3], args[4], args[5]);
        }


        if ((display_mask & DM_USER) != 0) {

                if (proto != NULL) {
                        oper = proto_get_oper(proto, IPC_GET_IMETHOD(*call));
                } else {
                        oper = NULL;
                }

                if (oper != NULL) {

                        printf("%s(%d).%s", (proto ? proto->name : "n/a"),
                            phone, (oper ? oper->name : "unknown"));

                        putchar('(');
                        for (i = 1; i <= oper->argc; ++i) {
                                if (i > 1) printf(", ");
                                val_print(args[i], oper->arg_type[i - 1]);
                        }
                        putchar(')');

                        if (oper->rv_type == V_VOID && oper->respc == 0) {
                                /*
                                 * No response data (typically the task will
                                 * not be interested in the response).
                                 * We will not display response.
                                 */
                                putchar('.');
                        }

                        putchar('\n');
                }
        } else {
                oper = NULL;
        }

        /* Store call in hash table for response matching */

        pcall = malloc(sizeof(pending_call_t));
        pcall->phone_hash = phone;
        pcall->question = *call;
        pcall->call_hash = hash;
        pcall->oper = oper;

        key[0] = hash;

        hash_table_insert(&pending_calls, key, &pcall->link);
}

static void parse_answer(ipc_callid_t hash, pending_call_t *pcall,
    ipc_call_t *answer)
{
        sysarg_t phone;
        sysarg_t method;
        sysarg_t service;
        sysarg_t retval;
        proto_t *proto;
        int cphone;

        sysarg_t *resp;
        oper_t *oper;
        int i;

//      printf("parse_answer\n");

        phone = pcall->phone_hash;
        method = IPC_GET_IMETHOD(pcall->question);
        retval = IPC_GET_RETVAL(*answer);

        resp = answer->args;

        if ((display_mask & DM_IPC) != 0) {
                printf("Response to %p: retval=%" PRIdn ", args = (%" PRIun ", "
                    "%" PRIun ", %" PRIun ", %" PRIun ", %" PRIun ")\n",
                    (void *) hash, retval, IPC_GET_ARG1(*answer),
                    IPC_GET_ARG2(*answer), IPC_GET_ARG3(*answer),
                    IPC_GET_ARG4(*answer), IPC_GET_ARG5(*answer));
        }

        if ((display_mask & DM_USER) != 0) {
                oper = pcall->oper;

                if (oper != NULL && (oper->rv_type != V_VOID || oper->respc > 0)) {
                        printf("->");

                        if (oper->rv_type != V_VOID) {
                                putchar(' ');
                                val_print(retval, oper->rv_type);
                        }
                        
                        if (oper->respc > 0) {
                                putchar(' ');
                                putchar('(');
                                for (i = 1; i <= oper->respc; ++i) {
                                        if (i > 1) printf(", ");
                                        val_print(resp[i], oper->resp_type[i - 1]);
                                }
                                putchar(')');
                        }

                        putchar('\n');
                }
        }

        if (phone == 0 && method == IPC_M_CONNECT_ME_TO && retval == 0) {
                /* Connected to a service (through NS) */
                service = IPC_GET_ARG1(pcall->question);
                proto = proto_get_by_srv(service);
                if (proto == NULL) proto = proto_unknown;

                cphone = IPC_GET_ARG5(*answer);
                if ((display_mask & DM_SYSTEM) != 0) {
                        printf("Registering connection (phone %d, protocol: %s)\n", cphone,
                                proto->name);
                }
                ipcp_connection_set(cphone, 0, proto);
        }
}

void ipcp_call_in(ipc_call_t *call, ipc_callid_t hash)
{
        link_t *item;
        pending_call_t *pcall;
        unsigned long key[1];

//      printf("ipcp_call_in()\n");

        if ((hash & IPC_CALLID_ANSWERED) == 0 && hash != IPCP_CALLID_SYNC) {
                /* Not a response */
                if ((display_mask & DM_IPC) != 0) {
                        printf("Not a response (hash %p)\n", (void *) hash);
                }
                return;
        }

        hash = hash & ~IPC_CALLID_ANSWERED;
        key[0] = hash;

        item = hash_table_find(&pending_calls, key);
        if (item == NULL) return; // No matching question found

        /*
         * Response matched to question.
         */
        
        pcall = hash_table_get_instance(item, pending_call_t, link);
        hash_table_remove(&pending_calls, key, 1);

        parse_answer(hash, pcall, call);
        free(pcall);
}

void ipcp_call_sync(int phone, ipc_call_t *call, ipc_call_t *answer)
{
        ipcp_call_out(phone, call, IPCP_CALLID_SYNC);
        ipcp_call_in(answer, IPCP_CALLID_SYNC);
}

void ipcp_hangup(int phone, int rc)
{
        if ((display_mask & DM_SYSTEM) != 0) {
                printf("Hang phone %d up -> %d\n", phone, rc);
                ipcp_connection_clear(phone);
        }
}

---