ssl_engine_io.c

        if (e == APR_BRIGADE_SENTINEL(bb) || !APR_BUCKET_IS_EOS(e)) {
            e = apr_bucket_eos_create(f->c->bucket_alloc);
            APR_BRIGADE_INSERT_TAIL(bb, e);
        }

        ap_log_cerror(APLOG_MARK, APLOG_TRACE4, 0, f->c,
                      "buffered SSL brigade exhausted");
        /* Note that the filter must *not* be removed here; it may be
         * invoked again, see comment above. */
    }

    return APR_SUCCESS;
}

/* The request_rec pointer is passed in here only to ensure that the
 * filter chain is modified correctly when doing a TLS upgrade.  It
 * must *not* be used otherwise. */
static void ssl_io_input_add_filter(ssl_filter_ctx_t *filter_ctx, conn_rec *c,
                                    request_rec *r, SSL *ssl)
{
    bio_filter_in_ctx_t *inctx;

    inctx = apr_palloc(c->pool, sizeof(*inctx));

    filter_ctx->pInputFilter = ap_add_input_filter(ssl_io_filter, inctx, r, c);

#if MODSSL_USE_OPENSSL_PRE_1_1_API
    filter_ctx->pbioRead = BIO_new(&bio_filter_in_method);
#else
    filter_ctx->pbioRead = BIO_new(bio_filter_in_method);
#endif
    BIO_set_data(filter_ctx->pbioRead, (void *)inctx);

    inctx->ssl = ssl;
    inctx->bio_out = filter_ctx->pbioWrite;
    inctx->f = filter_ctx->pInputFilter;
    inctx->rc = APR_SUCCESS;
    inctx->mode = AP_MODE_READBYTES;
    inctx->cbuf.length = 0;
    inctx->bb = apr_brigade_create(c->pool, c->bucket_alloc);
    inctx->block = APR_BLOCK_READ;
    inctx->pool = c->pool;
    inctx->filter_ctx = filter_ctx;
}

/* The request_rec pointer is passed in here only to ensure that the
 * filter chain is modified correctly when doing a TLS upgrade.  It
 * must *not* be used otherwise. */
void ssl_io_filter_init(conn_rec *c, request_rec *r, SSL *ssl)
{
    ssl_filter_ctx_t *filter_ctx;

    filter_ctx = apr_palloc(c->pool, sizeof(ssl_filter_ctx_t));

    filter_ctx->config          = myConnConfig(c);

    ap_add_output_filter(ssl_io_coalesce, NULL, r, c);

    filter_ctx->pOutputFilter   = ap_add_output_filter(ssl_io_filter,
                                                       filter_ctx, r, c);

#if MODSSL_USE_OPENSSL_PRE_1_1_API
    filter_ctx->pbioWrite       = BIO_new(&bio_filter_out_method);
#else
    filter_ctx->pbioWrite       = BIO_new(bio_filter_out_method);
#endif
    BIO_set_data(filter_ctx->pbioWrite, (void *)bio_filter_out_ctx_new(filter_ctx, c));

    /* write is non blocking for the benefit of async mpm */
    if (c->cs) {
        BIO_set_nbio(filter_ctx->pbioWrite, 1);
    }

    ssl_io_input_add_filter(filter_ctx, c, r, ssl);

    SSL_set_bio(ssl, filter_ctx->pbioRead, filter_ctx->pbioWrite);
    filter_ctx->pssl            = ssl;

    apr_pool_cleanup_register(c->pool, (void*)filter_ctx,
                              ssl_io_filter_cleanup, apr_pool_cleanup_null);

    if (APLOG_CS_IS_LEVEL(c, mySrvFromConn(c), APLOG_TRACE4)) {
        BIO *rbio = SSL_get_rbio(ssl),
            *wbio = SSL_get_wbio(ssl);
        BIO_set_callback(rbio, ssl_io_data_cb);
        BIO_set_callback_arg(rbio, (void *)ssl);
        if (wbio && wbio != rbio) {
            BIO_set_callback(wbio, ssl_io_data_cb);
            BIO_set_callback_arg(wbio, (void *)ssl);
        }
    }

    return;
}

void ssl_io_filter_register(apr_pool_t *p)
{
    ap_register_input_filter  (ssl_io_filter, ssl_io_filter_input,  NULL, AP_FTYPE_CONNECTION + 5);
    ap_register_output_filter (ssl_io_coalesce, ssl_io_filter_coalesce, NULL, AP_FTYPE_CONNECTION + 4);
    ap_register_output_filter (ssl_io_filter, ssl_io_filter_output, NULL, AP_FTYPE_CONNECTION + 5);

    ap_register_input_filter  (ssl_io_buffer, ssl_io_filter_buffer, NULL, AP_FTYPE_PROTOCOL);

    return;
}

/*  _________________________________________________________________
**
**  I/O Data Debugging
**  _________________________________________________________________
*/

#define DUMP_WIDTH 16

static void ssl_io_data_dump(server_rec *s,
                             const char *b,
                             long len)
{
    char buf[256];
    char tmp[64];
    int i, j, rows, trunc;
    unsigned char ch;

    trunc = 0;
    for(; (len > 0) && ((b[len-1] == ' ') || (b[len-1] == '\0')); len--)
        trunc++;
    rows = (len / DUMP_WIDTH);
    if ((rows * DUMP_WIDTH) < len)
        rows++;
    ap_log_error(APLOG_MARK, APLOG_TRACE7, 0, s,
            "+-------------------------------------------------------------------------+");
    for(i = 0 ; i< rows; i++) {
#if APR_CHARSET_EBCDIC
        char ebcdic_text[DUMP_WIDTH];
        j = DUMP_WIDTH;
        if ((i * DUMP_WIDTH + j) > len)
            j = len % DUMP_WIDTH;
        if (j == 0)
            j = DUMP_WIDTH;
        memcpy(ebcdic_text,(char *)(b) + i * DUMP_WIDTH, j);
        ap_xlate_proto_from_ascii(ebcdic_text, j);
#endif /* APR_CHARSET_EBCDIC */
        apr_snprintf(tmp, sizeof(tmp), "| %04x: ", i * DUMP_WIDTH);
        apr_cpystrn(buf, tmp, sizeof(buf));
        for (j = 0; j < DUMP_WIDTH; j++) {
            if (((i * DUMP_WIDTH) + j) >= len)
                apr_cpystrn(buf+strlen(buf), "   ", sizeof(buf)-strlen(buf));
            else {
                ch = ((unsigned char)*((char *)(b) + i * DUMP_WIDTH + j)) & 0xff;
                apr_snprintf(tmp, sizeof(tmp), "%02x%c", ch , j==7 ? '-' : ' ');
                apr_cpystrn(buf+strlen(buf), tmp, sizeof(buf)-strlen(buf));
            }
        }
        apr_cpystrn(buf+strlen(buf), " ", sizeof(buf)-strlen(buf));
        for (j = 0; j < DUMP_WIDTH; j++) {
            if (((i * DUMP_WIDTH) + j) >= len)
                apr_cpystrn(buf+strlen(buf), " ", sizeof(buf)-strlen(buf));
            else {
                ch = ((unsigned char)*((char *)(b) + i * DUMP_WIDTH + j)) & 0xff;
#if APR_CHARSET_EBCDIC
                apr_snprintf(tmp, sizeof(tmp), "%c", (ch >= 0x20 && ch <= 0x7F) ? ebcdic_text[j] : '.');
#else /* APR_CHARSET_EBCDIC */
                apr_snprintf(tmp, sizeof(tmp), "%c", ((ch >= ' ') && (ch <= '~')) ? ch : '.');
#endif /* APR_CHARSET_EBCDIC */
                apr_cpystrn(buf+strlen(buf), tmp, sizeof(buf)-strlen(buf));
            }
        }
        apr_cpystrn(buf+strlen(buf), " |", sizeof(buf)-strlen(buf));
        ap_log_error(APLOG_MARK, APLOG_TRACE7, 0, s, "%s", buf);
    }
    if (trunc > 0)
        ap_log_error(APLOG_MARK, APLOG_TRACE7, 0, s,
                "| %04ld - <SPACES/NULS>", len + trunc);
    ap_log_error(APLOG_MARK, APLOG_TRACE7, 0, s,
            "+-------------------------------------------------------------------------+");
    return;
}

long ssl_io_data_cb(BIO *bio, int cmd,
                    const char *argp,
                    int argi, long argl, long rc)
{
    SSL *ssl;
    conn_rec *c;
    server_rec *s;

    if ((ssl = (SSL *)BIO_get_callback_arg(bio)) == NULL)
        return rc;
    if ((c = (conn_rec *)SSL_get_app_data(ssl)) == NULL)
        return rc;
    s = mySrvFromConn(c);

    if (   cmd == (BIO_CB_WRITE|BIO_CB_RETURN)
        || cmd == (BIO_CB_READ |BIO_CB_RETURN) ) {
        if (rc >= 0) {
            ap_log_cserror(APLOG_MARK, APLOG_TRACE4, 0, c, s,
                    "%s: %s %ld/%d bytes %s BIO#%pp [mem: %pp] %s",
                    MODSSL_LIBRARY_NAME,
                    (cmd == (BIO_CB_WRITE|BIO_CB_RETURN) ? "write" : "read"),
                    rc, argi, (cmd == (BIO_CB_WRITE|BIO_CB_RETURN) ? "to" : "from"),
                    bio, argp,
                    (argp != NULL ? "(BIO dump follows)" : "(Oops, no memory buffer?)"));
            if ((argp != NULL) && APLOG_CS_IS_LEVEL(c, s, APLOG_TRACE7))
                ssl_io_data_dump(s, argp, rc);
        }
        else {
            ap_log_cserror(APLOG_MARK, APLOG_TRACE4, 0, c, s,
                    "%s: I/O error, %d bytes expected to %s on BIO#%pp [mem: %pp]",
                    MODSSL_LIBRARY_NAME, argi,
                    (cmd == (BIO_CB_WRITE|BIO_CB_RETURN) ? "write" : "read"),
                    bio, argp);
        }
    }
    return rc;
}