/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <stdlib.h>
#include <assert.h>
#include <ctype.h>
#include <pthread.h>
#include <strings.h>
#include <sip.h>

#include "sip_miscdefs.h"

/*
 * Local version of case insensitive strstr().
 */
static char *
sip_reass_strstr(const char *as1, const char *as2)
{
        const char      *s1;
        const char      *s2;
        const char      *tptr;
        char    c;

        s1 = as1;
        s2 = as2;

        if (s2 == NULL || *s2 == '\0')
                return ((char *)s1);
        c = *s2;

        while (*s1)
                if (tolower(*s1++) == c) {
                        tptr = s1;
                        while ((c = *++s2) == tolower(*s1++) && c)
                                ;
                        if (c == 0)
                                return ((char *)tptr - 1);
                        s1 = tptr;
                        s2 = as2;
                        c = *s2;
                }

        return (NULL);
}

/*
 * Get the value in the content-length field and add it to the header length
 * and return the total length. returns -1 if the length cannot be determined
 * or if the message does not contain the entire message.
 */
static int
sip_get_msglen(char *p, size_t msglen)
{
        int     value = 0;
        int     hlen;
        char    *c;
        char    *e;
        int     base = 10;
        char    *edge;
        int     digits = 0;

        edge = p + msglen;
        if ((c = sip_reass_strstr(p, "content-length")) == NULL)
                return (-1);
        hlen = c - p;
        if ((hlen +  strlen("content-length")) >= msglen)
                return (-1);
        c += strlen("content-length");
        e = c + 1;
        while (*e == ' ' || *e == ':') {
                e++;
                if (e == edge)
                        return (-1);
        }
        while (*e  != '\r' && *e != ' ') {
                if (e == edge)
                        return (-1);
                if (*e >= '0' && *e <= '9')
                        digits = *e - '0';
                else
                        return (-1);
                value = (value * base) + digits;
                e++;
        }
        while (*e != '\r') {
                e++;
                if (e == edge)
                        return (-1);
        }
        hlen = e - p + 4;       /* 4 for 2 CRLFs ?? */
        value += hlen;

        return (value);
}

/*
 * We have determined that msg does not contain a *single* complete message.
 * Add it to the reassembly list and check if we have a complete message.
 * a NULL 'msg' means we are just checking if there are more complete
 * messages in the list that can be passed up.
 */
char *
sip_get_tcp_msg(sip_conn_object_t obj, char *msg, size_t *msglen)
{
        int                     value;
        sip_conn_obj_pvt_t      *pvt_data;
        sip_reass_entry_t       *reass;
        void                    **obj_val;
        char                    *msgbuf = NULL;
        int                     splitlen;
        char                    *splitbuf;

        if (msg != NULL) {
                assert(*msglen > 0);
                msgbuf = (char *)malloc(*msglen + 1);
                if (msgbuf == NULL)
                        return (NULL);
                (void) strncpy(msgbuf, msg, *msglen);
                msgbuf[*msglen] = '\0';
                msg = msgbuf;
        }
        obj_val = (void *)obj;
        pvt_data = (sip_conn_obj_pvt_t *)*obj_val;
        /*
         * connection object not initialized
         */
        if (pvt_data == NULL) {
                if (msg == NULL)
                        return (NULL);
                value = sip_get_msglen(msg, *msglen);
                if (value == *msglen) {
                        return (msg);
                } else {
                        if (msgbuf != NULL)
                                free(msgbuf);
                        return (NULL);
                }
        }
        (void) pthread_mutex_lock(&pvt_data->sip_conn_obj_reass_lock);
        reass = pvt_data->sip_conn_obj_reass;
        assert(reass != NULL);
        if (reass->sip_reass_msg == NULL) {
                assert(reass->sip_reass_msglen == 0);
                if (msg == NULL) {
                        (void) pthread_mutex_unlock(
                            &pvt_data->sip_conn_obj_reass_lock);
                        return (NULL);
                }
                value = sip_get_msglen(msg, *msglen);
                if (value == *msglen) {
                        (void) pthread_mutex_unlock(
                            &pvt_data->sip_conn_obj_reass_lock);
                        return (msg);
                }
                reass->sip_reass_msg = msg;
                reass->sip_reass_msglen = *msglen;
                if (value != -1 && value < reass->sip_reass_msglen)
                        goto tryone;
                (void) pthread_mutex_unlock(&pvt_data->sip_conn_obj_reass_lock);
                return (NULL);
        } else if (msg != NULL) {
                /*
                 * Resize, not optimal
                 */
                int     newlen = reass->sip_reass_msglen + *msglen;
                char    *newmsg;

                assert(strlen(reass->sip_reass_msg) == reass->sip_reass_msglen);
                newmsg = malloc(newlen + 1);
                if (newmsg == NULL) {
                        (void) pthread_mutex_unlock(
                            &pvt_data->sip_conn_obj_reass_lock);
                        if (msgbuf != NULL)
                                free(msgbuf);
                        return (NULL);
                }
                (void) strncpy(newmsg, reass->sip_reass_msg,
                    reass->sip_reass_msglen);
                newmsg[reass->sip_reass_msglen] = '\0';
                (void) strncat(newmsg, msg, *msglen);
                newmsg[newlen] = '\0';
                assert(strlen(newmsg) == newlen);
                reass->sip_reass_msglen = newlen;
                free(msg);
                free(reass->sip_reass_msg);
                reass->sip_reass_msg = newmsg;
        }
        value = sip_get_msglen(reass->sip_reass_msg, reass->sip_reass_msglen);
        if (value == -1 || value >  reass->sip_reass_msglen) {
                (void) pthread_mutex_unlock(&pvt_data->sip_conn_obj_reass_lock);
                return (NULL);
        }
tryone:
        if (value == reass->sip_reass_msglen) {
                msg = reass->sip_reass_msg;
                *msglen = reass->sip_reass_msglen;
                reass->sip_reass_msg = NULL;
                reass->sip_reass_msglen = 0;
                (void) pthread_mutex_unlock(&pvt_data->sip_conn_obj_reass_lock);
                return (msg);
        }
        splitlen = reass->sip_reass_msglen - value;
        msg = (char *)malloc(value + 1);
        splitbuf = (char *)malloc(splitlen + 1);
        if (msg == NULL || splitbuf == NULL) {
                if (msg != NULL)
                        free(msg);
                if (splitbuf != NULL)
                        free(splitbuf);
                (void) pthread_mutex_unlock(&pvt_data->sip_conn_obj_reass_lock);
                return (NULL);
        }
        (void) strncpy(msg, reass->sip_reass_msg, value);
        msg[value] = '\0';
        (void) strncpy(splitbuf, reass->sip_reass_msg + value, splitlen);
        splitbuf[splitlen] = '\0';
        free(reass->sip_reass_msg);
        reass->sip_reass_msg = splitbuf;
        reass->sip_reass_msglen = splitlen;
        (void) pthread_mutex_unlock(&pvt_data->sip_conn_obj_reass_lock);
        *msglen = value;
        return (msg);
}