75 lines
1.7 KiB
C
75 lines
1.7 KiB
C
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/*
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* This file Copyright (C) 2016 Mnemosyne LLC
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*
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* It may be used under the GNU GPL versions 2 or 3
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* or any future license endorsed by Mnemosyne LLC.
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*
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*/
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#include <string.h>
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#include <time.h>
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#include "transmission.h"
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#include "crypto-utils.h"
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#include "session-id.h"
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#include "utils.h"
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#define SESSION_ID_SIZE 48
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#define SESSION_ID_DURATION_SEC (60 * 60) /* expire in an hour */
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struct tr_session_id
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{
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char * current_value;
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char * previous_value;
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time_t expires_at;
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};
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static char *
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generate_new_session_id_value (void)
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{
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const char pool[] = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
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const size_t pool_size = sizeof (pool) - 1;
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char * buf = tr_new (char, SESSION_ID_SIZE + 1);
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tr_rand_buffer (buf, SESSION_ID_SIZE);
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for (size_t i = 0; i < SESSION_ID_SIZE; ++i)
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buf[i] = pool[(unsigned char) buf[i] % pool_size];
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buf[SESSION_ID_SIZE] = '\0';
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return buf;
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}
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tr_session_id_t
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tr_session_id_new (void)
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{
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return tr_new0 (struct tr_session_id, 1);
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}
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void
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tr_session_id_free (tr_session_id_t session_id)
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{
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if (session_id == NULL)
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return;
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tr_free (session_id->previous_value);
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tr_free (session_id->current_value);
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tr_free (session_id);
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}
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const char *
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tr_session_id_get_current (tr_session_id_t session_id)
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{
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const time_t now = tr_time ();
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if (session_id->current_value == NULL || now >= session_id->expires_at)
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{
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tr_free (session_id->previous_value);
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session_id->previous_value = session_id->current_value;
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session_id->current_value = generate_new_session_id_value ();
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session_id->expires_at = now + SESSION_ID_DURATION_SEC;
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}
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return session_id->current_value;
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}
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