view src/stream/ngx_stream_script.c @ 8971:1e2f4e9c8195 quic

QUIC: reworked migration handling. The quic connection now holds active, backup and probe paths instead of sockets. The number of migration paths is now limited and cannot be inflated by a bad client or an attacker. The client id is now associated with path rather than socket. This allows to simplify processing of output and connection ids handling. New migration abandons any previously started migrations. This allows to free consumed client ids and request new for use in future migrations and make progress in case when connection id limit is hit during migration. A path now can be revalidated without losing its state. The patch also fixes various issues with NAT rebinding case handling: - paths are now validated (previously, there was no validation and paths were left in limited state) - attempt to reuse id on different path is now again verified (this was broken in 40445fc7c403) - former path is now validated in case of apparent migration
author Vladimir Homutov <vl@nginx.com>
date Wed, 19 Jan 2022 22:39:24 +0300
parents 3ab8e1e2f0f7
children
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_stream.h>


static ngx_int_t ngx_stream_script_init_arrays(
    ngx_stream_script_compile_t *sc);
static ngx_int_t ngx_stream_script_done(ngx_stream_script_compile_t *sc);
static ngx_int_t ngx_stream_script_add_copy_code(
    ngx_stream_script_compile_t *sc, ngx_str_t *value, ngx_uint_t last);
static ngx_int_t ngx_stream_script_add_var_code(
    ngx_stream_script_compile_t *sc, ngx_str_t *name);
#if (NGX_PCRE)
static ngx_int_t ngx_stream_script_add_capture_code(
    ngx_stream_script_compile_t *sc, ngx_uint_t n);
#endif
static ngx_int_t ngx_stream_script_add_full_name_code(
    ngx_stream_script_compile_t *sc);
static size_t ngx_stream_script_full_name_len_code(
    ngx_stream_script_engine_t *e);
static void ngx_stream_script_full_name_code(ngx_stream_script_engine_t *e);


#define ngx_stream_script_exit  (u_char *) &ngx_stream_script_exit_code

static uintptr_t ngx_stream_script_exit_code = (uintptr_t) NULL;


void
ngx_stream_script_flush_complex_value(ngx_stream_session_t *s,
    ngx_stream_complex_value_t *val)
{
    ngx_uint_t *index;

    index = val->flushes;

    if (index) {
        while (*index != (ngx_uint_t) -1) {

            if (s->variables[*index].no_cacheable) {
                s->variables[*index].valid = 0;
                s->variables[*index].not_found = 0;
            }

            index++;
        }
    }
}


ngx_int_t
ngx_stream_complex_value(ngx_stream_session_t *s,
    ngx_stream_complex_value_t *val, ngx_str_t *value)
{
    size_t                         len;
    ngx_stream_script_code_pt      code;
    ngx_stream_script_engine_t     e;
    ngx_stream_script_len_code_pt  lcode;

    if (val->lengths == NULL) {
        *value = val->value;
        return NGX_OK;
    }

    ngx_stream_script_flush_complex_value(s, val);

    ngx_memzero(&e, sizeof(ngx_stream_script_engine_t));

    e.ip = val->lengths;
    e.session = s;
    e.flushed = 1;

    len = 0;

    while (*(uintptr_t *) e.ip) {
        lcode = *(ngx_stream_script_len_code_pt *) e.ip;
        len += lcode(&e);
    }

    value->len = len;
    value->data = ngx_pnalloc(s->connection->pool, len);
    if (value->data == NULL) {
        return NGX_ERROR;
    }

    e.ip = val->values;
    e.pos = value->data;
    e.buf = *value;

    while (*(uintptr_t *) e.ip) {
        code = *(ngx_stream_script_code_pt *) e.ip;
        code((ngx_stream_script_engine_t *) &e);
    }

    *value = e.buf;

    return NGX_OK;
}


size_t
ngx_stream_complex_value_size(ngx_stream_session_t *s,
    ngx_stream_complex_value_t *val, size_t default_value)
{
    size_t     size;
    ngx_str_t  value;

    if (val == NULL) {
        return default_value;
    }

    if (val->lengths == NULL) {
        return val->u.size;
    }

    if (ngx_stream_complex_value(s, val, &value) != NGX_OK) {
        return default_value;
    }

    size = ngx_parse_size(&value);

    if (size == (size_t) NGX_ERROR) {
        ngx_log_error(NGX_LOG_ERR, s->connection->log, 0,
                      "invalid size \"%V\"", &value);
        return default_value;
    }

    return size;
}


ngx_int_t
ngx_stream_compile_complex_value(ngx_stream_compile_complex_value_t *ccv)
{
    ngx_str_t                    *v;
    ngx_uint_t                    i, n, nv, nc;
    ngx_array_t                   flushes, lengths, values, *pf, *pl, *pv;
    ngx_stream_script_compile_t   sc;

    v = ccv->value;

    nv = 0;
    nc = 0;

    for (i = 0; i < v->len; i++) {
        if (v->data[i] == '$') {
            if (v->data[i + 1] >= '1' && v->data[i + 1] <= '9') {
                nc++;

            } else {
                nv++;
            }
        }
    }

    if ((v->len == 0 || v->data[0] != '$')
        && (ccv->conf_prefix || ccv->root_prefix))
    {
        if (ngx_conf_full_name(ccv->cf->cycle, v, ccv->conf_prefix) != NGX_OK) {
            return NGX_ERROR;
        }

        ccv->conf_prefix = 0;
        ccv->root_prefix = 0;
    }

    ccv->complex_value->value = *v;
    ccv->complex_value->flushes = NULL;
    ccv->complex_value->lengths = NULL;
    ccv->complex_value->values = NULL;

    if (nv == 0 && nc == 0) {
        return NGX_OK;
    }

    n = nv + 1;

    if (ngx_array_init(&flushes, ccv->cf->pool, n, sizeof(ngx_uint_t))
        != NGX_OK)
    {
        return NGX_ERROR;
    }

    n = nv * (2 * sizeof(ngx_stream_script_copy_code_t)
                  + sizeof(ngx_stream_script_var_code_t))
        + sizeof(uintptr_t);

    if (ngx_array_init(&lengths, ccv->cf->pool, n, 1) != NGX_OK) {
        return NGX_ERROR;
    }

    n = (nv * (2 * sizeof(ngx_stream_script_copy_code_t)
                   + sizeof(ngx_stream_script_var_code_t))
                + sizeof(uintptr_t)
                + v->len
                + sizeof(uintptr_t) - 1)
            & ~(sizeof(uintptr_t) - 1);

    if (ngx_array_init(&values, ccv->cf->pool, n, 1) != NGX_OK) {
        return NGX_ERROR;
    }

    pf = &flushes;
    pl = &lengths;
    pv = &values;

    ngx_memzero(&sc, sizeof(ngx_stream_script_compile_t));

    sc.cf = ccv->cf;
    sc.source = v;
    sc.flushes = &pf;
    sc.lengths = &pl;
    sc.values = &pv;
    sc.complete_lengths = 1;
    sc.complete_values = 1;
    sc.zero = ccv->zero;
    sc.conf_prefix = ccv->conf_prefix;
    sc.root_prefix = ccv->root_prefix;

    if (ngx_stream_script_compile(&sc) != NGX_OK) {
        return NGX_ERROR;
    }

    if (flushes.nelts) {
        ccv->complex_value->flushes = flushes.elts;
        ccv->complex_value->flushes[flushes.nelts] = (ngx_uint_t) -1;
    }

    ccv->complex_value->lengths = lengths.elts;
    ccv->complex_value->values = values.elts;

    return NGX_OK;
}


char *
ngx_stream_set_complex_value_slot(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf)
{
    char  *p = conf;

    ngx_str_t                            *value;
    ngx_stream_complex_value_t          **cv;
    ngx_stream_compile_complex_value_t    ccv;

    cv = (ngx_stream_complex_value_t **) (p + cmd->offset);

    if (*cv != NGX_CONF_UNSET_PTR && *cv != NULL) {
        return "is duplicate";
    }

    *cv = ngx_palloc(cf->pool, sizeof(ngx_stream_complex_value_t));
    if (*cv == NULL) {
        return NGX_CONF_ERROR;
    }

    value = cf->args->elts;

    ngx_memzero(&ccv, sizeof(ngx_stream_compile_complex_value_t));

    ccv.cf = cf;
    ccv.value = &value[1];
    ccv.complex_value = *cv;

    if (ngx_stream_compile_complex_value(&ccv) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    return NGX_CONF_OK;
}


char *
ngx_stream_set_complex_value_zero_slot(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf)
{
    char  *p = conf;

    ngx_str_t                            *value;
    ngx_stream_complex_value_t          **cv;
    ngx_stream_compile_complex_value_t    ccv;

    cv = (ngx_stream_complex_value_t **) (p + cmd->offset);

    if (*cv != NGX_CONF_UNSET_PTR) {
        return "is duplicate";
    }

    *cv = ngx_palloc(cf->pool, sizeof(ngx_stream_complex_value_t));
    if (*cv == NULL) {
        return NGX_CONF_ERROR;
    }

    value = cf->args->elts;

    ngx_memzero(&ccv, sizeof(ngx_stream_compile_complex_value_t));

    ccv.cf = cf;
    ccv.value = &value[1];
    ccv.complex_value = *cv;
    ccv.zero = 1;

    if (ngx_stream_compile_complex_value(&ccv) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    return NGX_CONF_OK;
}


char *
ngx_stream_set_complex_value_size_slot(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf)
{
    char  *p = conf;

    char                        *rv;
    ngx_stream_complex_value_t  *cv;

    rv = ngx_stream_set_complex_value_slot(cf, cmd, conf);

    if (rv != NGX_CONF_OK) {
        return rv;
    }

    cv = *(ngx_stream_complex_value_t **) (p + cmd->offset);

    if (cv->lengths) {
        return NGX_CONF_OK;
    }

    cv->u.size = ngx_parse_size(&cv->value);
    if (cv->u.size == (size_t) NGX_ERROR) {
        return "invalid value";
    }

    return NGX_CONF_OK;
}


ngx_uint_t
ngx_stream_script_variables_count(ngx_str_t *value)
{
    ngx_uint_t  i, n;

    for (n = 0, i = 0; i < value->len; i++) {
        if (value->data[i] == '$') {
            n++;
        }
    }

    return n;
}


ngx_int_t
ngx_stream_script_compile(ngx_stream_script_compile_t *sc)
{
    u_char       ch;
    ngx_str_t    name;
    ngx_uint_t   i, bracket;

    if (ngx_stream_script_init_arrays(sc) != NGX_OK) {
        return NGX_ERROR;
    }

    for (i = 0; i < sc->source->len; /* void */ ) {

        name.len = 0;

        if (sc->source->data[i] == '$') {

            if (++i == sc->source->len) {
                goto invalid_variable;
            }

            if (sc->source->data[i] >= '1' && sc->source->data[i] <= '9') {
#if (NGX_PCRE)
                ngx_uint_t  n;

                n = sc->source->data[i] - '0';

                if (ngx_stream_script_add_capture_code(sc, n) != NGX_OK) {
                    return NGX_ERROR;
                }

                i++;

                continue;
#else
                ngx_conf_log_error(NGX_LOG_EMERG, sc->cf, 0,
                                   "using variable \"$%c\" requires "
                                   "PCRE library", sc->source->data[i]);
                return NGX_ERROR;
#endif
            }

            if (sc->source->data[i] == '{') {
                bracket = 1;

                if (++i == sc->source->len) {
                    goto invalid_variable;
                }

                name.data = &sc->source->data[i];

            } else {
                bracket = 0;
                name.data = &sc->source->data[i];
            }

            for ( /* void */ ; i < sc->source->len; i++, name.len++) {
                ch = sc->source->data[i];

                if (ch == '}' && bracket) {
                    i++;
                    bracket = 0;
                    break;
                }

                if ((ch >= 'A' && ch <= 'Z')
                    || (ch >= 'a' && ch <= 'z')
                    || (ch >= '0' && ch <= '9')
                    || ch == '_')
                {
                    continue;
                }

                break;
            }

            if (bracket) {
                ngx_conf_log_error(NGX_LOG_EMERG, sc->cf, 0,
                                   "the closing bracket in \"%V\" "
                                   "variable is missing", &name);
                return NGX_ERROR;
            }

            if (name.len == 0) {
                goto invalid_variable;
            }

            sc->variables++;

            if (ngx_stream_script_add_var_code(sc, &name) != NGX_OK) {
                return NGX_ERROR;
            }

            continue;
        }

        name.data = &sc->source->data[i];

        while (i < sc->source->len) {

            if (sc->source->data[i] == '$') {
                break;
            }

            i++;
            name.len++;
        }

        sc->size += name.len;

        if (ngx_stream_script_add_copy_code(sc, &name, (i == sc->source->len))
            != NGX_OK)
        {
            return NGX_ERROR;
        }
    }

    return ngx_stream_script_done(sc);

invalid_variable:

    ngx_conf_log_error(NGX_LOG_EMERG, sc->cf, 0, "invalid variable name");

    return NGX_ERROR;
}


u_char *
ngx_stream_script_run(ngx_stream_session_t *s, ngx_str_t *value,
    void *code_lengths, size_t len, void *code_values)
{
    ngx_uint_t                      i;
    ngx_stream_script_code_pt       code;
    ngx_stream_script_engine_t      e;
    ngx_stream_core_main_conf_t    *cmcf;
    ngx_stream_script_len_code_pt   lcode;

    cmcf = ngx_stream_get_module_main_conf(s, ngx_stream_core_module);

    for (i = 0; i < cmcf->variables.nelts; i++) {
        if (s->variables[i].no_cacheable) {
            s->variables[i].valid = 0;
            s->variables[i].not_found = 0;
        }
    }

    ngx_memzero(&e, sizeof(ngx_stream_script_engine_t));

    e.ip = code_lengths;
    e.session = s;
    e.flushed = 1;

    while (*(uintptr_t *) e.ip) {
        lcode = *(ngx_stream_script_len_code_pt *) e.ip;
        len += lcode(&e);
    }


    value->len = len;
    value->data = ngx_pnalloc(s->connection->pool, len);
    if (value->data == NULL) {
        return NULL;
    }

    e.ip = code_values;
    e.pos = value->data;

    while (*(uintptr_t *) e.ip) {
        code = *(ngx_stream_script_code_pt *) e.ip;
        code((ngx_stream_script_engine_t *) &e);
    }

    return e.pos;
}


void
ngx_stream_script_flush_no_cacheable_variables(ngx_stream_session_t *s,
    ngx_array_t *indices)
{
    ngx_uint_t  n, *index;

    if (indices) {
        index = indices->elts;
        for (n = 0; n < indices->nelts; n++) {
            if (s->variables[index[n]].no_cacheable) {
                s->variables[index[n]].valid = 0;
                s->variables[index[n]].not_found = 0;
            }
        }
    }
}


static ngx_int_t
ngx_stream_script_init_arrays(ngx_stream_script_compile_t *sc)
{
    ngx_uint_t   n;

    if (sc->flushes && *sc->flushes == NULL) {
        n = sc->variables ? sc->variables : 1;
        *sc->flushes = ngx_array_create(sc->cf->pool, n, sizeof(ngx_uint_t));
        if (*sc->flushes == NULL) {
            return NGX_ERROR;
        }
    }

    if (*sc->lengths == NULL) {
        n = sc->variables * (2 * sizeof(ngx_stream_script_copy_code_t)
                             + sizeof(ngx_stream_script_var_code_t))
            + sizeof(uintptr_t);

        *sc->lengths = ngx_array_create(sc->cf->pool, n, 1);
        if (*sc->lengths == NULL) {
            return NGX_ERROR;
        }
    }

    if (*sc->values == NULL) {
        n = (sc->variables * (2 * sizeof(ngx_stream_script_copy_code_t)
                              + sizeof(ngx_stream_script_var_code_t))
                + sizeof(uintptr_t)
                + sc->source->len
                + sizeof(uintptr_t) - 1)
            & ~(sizeof(uintptr_t) - 1);

        *sc->values = ngx_array_create(sc->cf->pool, n, 1);
        if (*sc->values == NULL) {
            return NGX_ERROR;
        }
    }

    sc->variables = 0;

    return NGX_OK;
}


static ngx_int_t
ngx_stream_script_done(ngx_stream_script_compile_t *sc)
{
    ngx_str_t    zero;
    uintptr_t   *code;

    if (sc->zero) {

        zero.len = 1;
        zero.data = (u_char *) "\0";

        if (ngx_stream_script_add_copy_code(sc, &zero, 0) != NGX_OK) {
            return NGX_ERROR;
        }
    }

    if (sc->conf_prefix || sc->root_prefix) {
        if (ngx_stream_script_add_full_name_code(sc) != NGX_OK) {
            return NGX_ERROR;
        }
    }

    if (sc->complete_lengths) {
        code = ngx_stream_script_add_code(*sc->lengths, sizeof(uintptr_t),
                                          NULL);
        if (code == NULL) {
            return NGX_ERROR;
        }

        *code = (uintptr_t) NULL;
    }

    if (sc->complete_values) {
        code = ngx_stream_script_add_code(*sc->values, sizeof(uintptr_t),
                                          &sc->main);
        if (code == NULL) {
            return NGX_ERROR;
        }

        *code = (uintptr_t) NULL;
    }

    return NGX_OK;
}


void *
ngx_stream_script_add_code(ngx_array_t *codes, size_t size, void *code)
{
    u_char  *elts, **p;
    void    *new;

    elts = codes->elts;

    new = ngx_array_push_n(codes, size);
    if (new == NULL) {
        return NULL;
    }

    if (code) {
        if (elts != codes->elts) {
            p = code;
            *p += (u_char *) codes->elts - elts;
        }
    }

    return new;
}


static ngx_int_t
ngx_stream_script_add_copy_code(ngx_stream_script_compile_t *sc,
    ngx_str_t *value, ngx_uint_t last)
{
    u_char                         *p;
    size_t                          size, len, zero;
    ngx_stream_script_copy_code_t  *code;

    zero = (sc->zero && last);
    len = value->len + zero;

    code = ngx_stream_script_add_code(*sc->lengths,
                                      sizeof(ngx_stream_script_copy_code_t),
                                      NULL);
    if (code == NULL) {
        return NGX_ERROR;
    }

    code->code = (ngx_stream_script_code_pt) (void *)
                                               ngx_stream_script_copy_len_code;
    code->len = len;

    size = (sizeof(ngx_stream_script_copy_code_t) + len + sizeof(uintptr_t) - 1)
            & ~(sizeof(uintptr_t) - 1);

    code = ngx_stream_script_add_code(*sc->values, size, &sc->main);
    if (code == NULL) {
        return NGX_ERROR;
    }

    code->code = ngx_stream_script_copy_code;
    code->len = len;

    p = ngx_cpymem((u_char *) code + sizeof(ngx_stream_script_copy_code_t),
                   value->data, value->len);

    if (zero) {
        *p = '\0';
        sc->zero = 0;
    }

    return NGX_OK;
}


size_t
ngx_stream_script_copy_len_code(ngx_stream_script_engine_t *e)
{
    ngx_stream_script_copy_code_t  *code;

    code = (ngx_stream_script_copy_code_t *) e->ip;

    e->ip += sizeof(ngx_stream_script_copy_code_t);

    return code->len;
}


void
ngx_stream_script_copy_code(ngx_stream_script_engine_t *e)
{
    u_char                         *p;
    ngx_stream_script_copy_code_t  *code;

    code = (ngx_stream_script_copy_code_t *) e->ip;

    p = e->pos;

    if (!e->skip) {
        e->pos = ngx_copy(p, e->ip + sizeof(ngx_stream_script_copy_code_t),
                          code->len);
    }

    e->ip += sizeof(ngx_stream_script_copy_code_t)
          + ((code->len + sizeof(uintptr_t) - 1) & ~(sizeof(uintptr_t) - 1));

    ngx_log_debug2(NGX_LOG_DEBUG_STREAM, e->session->connection->log, 0,
                   "stream script copy: \"%*s\"", e->pos - p, p);
}


static ngx_int_t
ngx_stream_script_add_var_code(ngx_stream_script_compile_t *sc, ngx_str_t *name)
{
    ngx_int_t                      index, *p;
    ngx_stream_script_var_code_t  *code;

    index = ngx_stream_get_variable_index(sc->cf, name);

    if (index == NGX_ERROR) {
        return NGX_ERROR;
    }

    if (sc->flushes) {
        p = ngx_array_push(*sc->flushes);
        if (p == NULL) {
            return NGX_ERROR;
        }

        *p = index;
    }

    code = ngx_stream_script_add_code(*sc->lengths,
                                      sizeof(ngx_stream_script_var_code_t),
                                      NULL);
    if (code == NULL) {
        return NGX_ERROR;
    }

    code->code = (ngx_stream_script_code_pt) (void *)
                                           ngx_stream_script_copy_var_len_code;
    code->index = (uintptr_t) index;

    code = ngx_stream_script_add_code(*sc->values,
                                      sizeof(ngx_stream_script_var_code_t),
                                      &sc->main);
    if (code == NULL) {
        return NGX_ERROR;
    }

    code->code = ngx_stream_script_copy_var_code;
    code->index = (uintptr_t) index;

    return NGX_OK;
}


size_t
ngx_stream_script_copy_var_len_code(ngx_stream_script_engine_t *e)
{
    ngx_stream_variable_value_t   *value;
    ngx_stream_script_var_code_t  *code;

    code = (ngx_stream_script_var_code_t *) e->ip;

    e->ip += sizeof(ngx_stream_script_var_code_t);

    if (e->flushed) {
        value = ngx_stream_get_indexed_variable(e->session, code->index);

    } else {
        value = ngx_stream_get_flushed_variable(e->session, code->index);
    }

    if (value && !value->not_found) {
        return value->len;
    }

    return 0;
}


void
ngx_stream_script_copy_var_code(ngx_stream_script_engine_t *e)
{
    u_char                        *p;
    ngx_stream_variable_value_t   *value;
    ngx_stream_script_var_code_t  *code;

    code = (ngx_stream_script_var_code_t *) e->ip;

    e->ip += sizeof(ngx_stream_script_var_code_t);

    if (!e->skip) {

        if (e->flushed) {
            value = ngx_stream_get_indexed_variable(e->session, code->index);

        } else {
            value = ngx_stream_get_flushed_variable(e->session, code->index);
        }

        if (value && !value->not_found) {
            p = e->pos;
            e->pos = ngx_copy(p, value->data, value->len);

            ngx_log_debug2(NGX_LOG_DEBUG_STREAM,
                           e->session->connection->log, 0,
                           "stream script var: \"%*s\"", e->pos - p, p);
        }
    }
}


#if (NGX_PCRE)

static ngx_int_t
ngx_stream_script_add_capture_code(ngx_stream_script_compile_t *sc,
    ngx_uint_t n)
{
    ngx_stream_script_copy_capture_code_t  *code;

    code = ngx_stream_script_add_code(*sc->lengths,
                                  sizeof(ngx_stream_script_copy_capture_code_t),
                                  NULL);
    if (code == NULL) {
        return NGX_ERROR;
    }

    code->code = (ngx_stream_script_code_pt) (void *)
                                       ngx_stream_script_copy_capture_len_code;
    code->n = 2 * n;


    code = ngx_stream_script_add_code(*sc->values,
                                  sizeof(ngx_stream_script_copy_capture_code_t),
                                  &sc->main);
    if (code == NULL) {
        return NGX_ERROR;
    }

    code->code = ngx_stream_script_copy_capture_code;
    code->n = 2 * n;

    if (sc->ncaptures < n) {
        sc->ncaptures = n;
    }

    return NGX_OK;
}


size_t
ngx_stream_script_copy_capture_len_code(ngx_stream_script_engine_t *e)
{
    int                                    *cap;
    ngx_uint_t                              n;
    ngx_stream_session_t                   *s;
    ngx_stream_script_copy_capture_code_t  *code;

    s = e->session;

    code = (ngx_stream_script_copy_capture_code_t *) e->ip;

    e->ip += sizeof(ngx_stream_script_copy_capture_code_t);

    n = code->n;

    if (n < s->ncaptures) {
        cap = s->captures;
        return cap[n + 1] - cap[n];
    }

    return 0;
}


void
ngx_stream_script_copy_capture_code(ngx_stream_script_engine_t *e)
{
    int                                    *cap;
    u_char                                 *p, *pos;
    ngx_uint_t                              n;
    ngx_stream_session_t                   *s;
    ngx_stream_script_copy_capture_code_t  *code;

    s = e->session;

    code = (ngx_stream_script_copy_capture_code_t *) e->ip;

    e->ip += sizeof(ngx_stream_script_copy_capture_code_t);

    n = code->n;

    pos = e->pos;

    if (n < s->ncaptures) {
        cap = s->captures;
        p = s->captures_data;
        e->pos = ngx_copy(pos, &p[cap[n]], cap[n + 1] - cap[n]);
    }

    ngx_log_debug2(NGX_LOG_DEBUG_STREAM, e->session->connection->log, 0,
                   "stream script capture: \"%*s\"", e->pos - pos, pos);
}

#endif


static ngx_int_t
ngx_stream_script_add_full_name_code(ngx_stream_script_compile_t *sc)
{
    ngx_stream_script_full_name_code_t  *code;

    code = ngx_stream_script_add_code(*sc->lengths,
                                    sizeof(ngx_stream_script_full_name_code_t),
                                    NULL);
    if (code == NULL) {
        return NGX_ERROR;
    }

    code->code = (ngx_stream_script_code_pt) (void *)
                                          ngx_stream_script_full_name_len_code;
    code->conf_prefix = sc->conf_prefix;

    code = ngx_stream_script_add_code(*sc->values,
                        sizeof(ngx_stream_script_full_name_code_t), &sc->main);
    if (code == NULL) {
        return NGX_ERROR;
    }

    code->code = ngx_stream_script_full_name_code;
    code->conf_prefix = sc->conf_prefix;

    return NGX_OK;
}


static size_t
ngx_stream_script_full_name_len_code(ngx_stream_script_engine_t *e)
{
    ngx_stream_script_full_name_code_t  *code;

    code = (ngx_stream_script_full_name_code_t *) e->ip;

    e->ip += sizeof(ngx_stream_script_full_name_code_t);

    return code->conf_prefix ? ngx_cycle->conf_prefix.len:
                               ngx_cycle->prefix.len;
}


static void
ngx_stream_script_full_name_code(ngx_stream_script_engine_t *e)
{
    ngx_stream_script_full_name_code_t  *code;

    ngx_str_t  value, *prefix;

    code = (ngx_stream_script_full_name_code_t *) e->ip;

    value.data = e->buf.data;
    value.len = e->pos - e->buf.data;

    prefix = code->conf_prefix ? (ngx_str_t *) &ngx_cycle->conf_prefix:
                                 (ngx_str_t *) &ngx_cycle->prefix;

    if (ngx_get_full_name(e->session->connection->pool, prefix, &value)
        != NGX_OK)
    {
        e->ip = ngx_stream_script_exit;
        return;
    }

    e->buf = value;

    ngx_log_debug1(NGX_LOG_DEBUG_STREAM, e->session->connection->log, 0,
                   "stream script fullname: \"%V\"", &value);

    e->ip += sizeof(ngx_stream_script_full_name_code_t);
}